PFC and FRFC were characterized using compression and tension tests. FRFC exhibited enhanced mechanical properties, which were attributed to the fibers. The dynamic tests showed that U-shaped walls made of FRFC performed better than those made of PFC. The time period prior to the collapse of the FRFC U-shaped walls was longer than that of the PFC specimens, which was attributed to the enhanced specimen integrity by the fibers. Finite element simulations of the shaking table test allowed for the prediction of the stress concentration and plastic strain that may lead to the failure of the U-shaped wall. These results showed that U-shaped walls made of FRFC have the potential to perform well in seismic applications, however, these results are preliminary and further studies are needed to support the findings of this work.Fiber-reinforced foamed concrete (FRFC) is a lightweight material that has the potential to perform well in seismic applications due to its low density and improved mechanical properties. However, studies focused on the seismic assessment of this material are limited. In this work, U-shaped wall specimens, made of FRFC reinforced with henequen fibers and plain foamed concrete (PFC) with a density of 900 kg/m Unreinforced masonry (URM) structures, such as those made of adobe, clay, bricks, or blocks, are used in many parts of the world because they are inexpensive, relatively easy to build and utilize locally available materials. However, in many cases, URM structures are unregulated, and are built using simple technology and low-quality construction practices . One maj3. They found that the frames built with the reduced-density wood-concrete blocks exhibited a superior seismic-resistant behavior when compared to those built with ordinary concrete blocks. Tomaževič and Gams [3. They found that the prototype buildings exhibited adequate seismic behavior when constructed as confined masonry systems. Dunn et al. [Several techniques have been developed to reinforce adobe and URM structures, including confinement of walls , retrofiand Gams ,27 studin et al.  studied 3 [Foamed concrete is a cementitious material, in which air-voids are trapped in the mortar. Foamed concrete is classified as a lightweight concrete, and its density can vary from 400 to 1600 kg/m3 . Foamed 3 . However3 . It has 3 ,33,34, b3 . This en3 ,36. Alth3 ,38, whic3 ,40, the 3 . The int3 . In addi3 . Recent 3 , sisal [3 , and hen3  fibers, 3, reinforced with the natural fiber henequen (Agave fourcroydes Lem.), which is one of the main cultivated species of Agave used to produce fibers in the south of Mexico. For this investigation, the dynamic cyclic loading response of U-shaped wall model specimens made of FRFC was studied by means of shaking table tests with a sinusoidal excitation, and the results were compared with those of non-reinforced foam concrete specimens. The mechanical characterization of the foamed concrete was performed using compression and tension tests. Finite-element (FE) simulations of the dynamic loading of U-shaped walls were performed to predict stress concentration that may lead to failure and improve the design of the U-shaped walls.Based on the aforementioned literature, fiber-reinforced foamed concrete (FRFC) has the potential to perform well in structural and seismic applications due to its low density and improved toughness and ductility by the fibers, effectively reducing the risk of earthquake damage, however, studies focusing on the seismic assessment of this type of material are limited in the literature. Hence, the objective of the present study is to investigate the seismic performance of FRFC with a density of 900 kg/m3 was used. The mixture was prepared using the following constituents for 1 m3: Portland cement CPC 30R EXTRA  with a minimum strength of 30 MPa at 28 days (427 kg), dry sand (214 kg), water (299 kg), and foam  (24 kg). The materials were mixed in a 60-L mixer STARK  until a homogeneous mixture was obtained. The mixture without fibers is referred to as plain foamed concrete (PFC). For the fiber-reinforced foamed concrete (FRFC), henequen fibers were gradually distributed, at random, by hand in small amounts into the mixture at the end of stage 3, at a fiber volume fraction of 0.5%. Henequen fibers were supplied by local producers . A fiber length of ~4 mm was used  is the weight of the cubical specimens, measured using an analytical balance Ohaus EB6 , and V (m3) is their volume. V was calculated using the dimensions measured by a digital caliper with a resolution of 0.05 mm ..5–2 GPa ,48. The To investigate the dynamic cyclic behavior of foamed concrete walls, 1:7.5 scaled U-shaped wall models were fabricated. The scaled U-shaped wall structure is intended to represent a wall section of a typical house, in the rural areas, in the state of Oaxaca, Mexico ,50. The 2, was attached to the right flange to record its acceleration history during the test  . Figure the test b. A fastthe test a.2 and ±19.8 mm, as expected, for the abovementioned sinusoidal excitation parameters.The numerical simulations of the U-shaped wall, subjected to dynamic cyclic loading, were performed using the finite-element (FE) software Abaqus/Explicit  . The FE 3, respectively. The elastic behavior of the foamed concrete material used for the U-shaped wall was modelled using a compression elastic modulus of E = 2 GPa, Poisson’s ratio of ν = 0.05 and density of ρ = 900 kg/m3. The plastic behavior was modelled using the Crushable Foam material model with the following parameters: compression yield stress ratio k = 1 and hydrostatic yield stress ratio tk = 0.1 [Steel parts and wooden base were modelled using densities of 7800 and 500 kg/mkt = 0.1 . For thekt = 0.1 . A failu2). To simulate the dynamic cyclic loading of the shaking table, the displacement–time history curve from Gravity load was applied to the entire model as a vertical acceleration field (−9.806 m/st = 1.89 s) using different element sizes. It is noted that in A mesh sensitivity analysis was carried out using three different element sizes: 10 mm (coarse mesh), 7 mm (intermediate mesh) and 5 mm (fine mesh), resulting in 2, 3, and 4 through-thickness elements, and a total of 4374, 11,520, and 34,556 elements, respectively. 2), which indicate the collapse of the right flange. In t = 1.5 s, there is plastic strain at the top corners of the U-shaped wall with flat corners, while for the U-shaped wall with round corners, there is no plastic strain  (c strain b. At t =(0.0008) d is much(0.0008) c. These The experimental results presented here have shown that henequen fiber-reinforcement can be used to improve the mechanical performance of U-shaped wall model specimens made of FRFC. This material has the potential to perform well in structural and seismic applications, and to be used for the fabrication of precast wall panels. However, we acknowledge that our results are preliminary and further experimental and numerical research has to be carried out to support the findings of this work. Further studies should include strategies to assess the effect of different fiber volume fractions and foamed concrete densities on the mechanical properties of the FRFC, an assessment of the durability of the henequen fibers in the cement-based foamed concrete, and further mechanical testing to fully understand the toughening mechanisms of the foamed concrete reinforced with natural fibers. For the U-shaped walls, it is necessary to test large scale models with different walling configurations, such as L-shaped walls. Dynamic testing should include different cyclic loadings and earthquakes excitations, and be performed using different loading directions. Although the experimental results presented here are limited, they provide useful knowledge about the behavior of fiber-reinforced materials and structures subjected to dynamic loading. These results could also be useful to validate numerical models that are used to predict seismic and dynamic behavior.The numerical results showed that the design of the U-shaped wall is crucial to reduce stress concentration that may lead to the formation of plastic strain, cracking and subsequent failure. The FE simulations presented here are important from a design viewpoint because they show that material properties and geometrical characteristics can potentially be tailored to improve seismic performance. These FE simulations could be extended to predict the seismic response of FRFC walls with more complex geometries, including the simulation of a full-scale U-shaped wall or a complete house. However, more mechanical testing is needed to obtain a complete set of parameters for material model calibration and numerical simulation validation. Finally, robust material models, that include failure criterion, should be employed to obtain more accurate predictions.3, were characterized using compression and tensile tests. These tests showed that the fiber-reinforcement improved the mechanical properties, toughness and ductility of the foamed concrete, which was attributed to the enhanced specimen integrity produced by the inclusion of the fibers. For the dynamic testing, the U-shaped walls were subjected to a 4-Hz sinusoidal base motion with an amplitude of 20 mm. The results showed that the U-shaped wall specimens made of FRFC performed better than those made of PFC because the time period prior to the collapse of the U-shaped walls was longer for the FRFC specimens, which was attributed to enhanced integrity of the specimens by the fibers. The finite element simulations proved to be a useful tool to improve the design of the U-shaped walls and predict stress concentration and the formation of plastic strain that may lead to cracking and failure during the dynamic cyclic loading. The results presented here showed that U-shaped walls made of FRFC have the potential to perform well in structural and seismic applications. However, these results are preliminary and further experimental and numerical research should be carried out to support the findings of this work.In this work, the mechanical performance of U-shaped wall model specimens subjected to dynamic cyclic loading, by means of shaking table tests, was investigated. The U-shaped walls were made of foamed concrete without fiber-reinforcement (PFC) and with fiber-reinforcement (PFC). Both PFC and FRFC, with a target dry density of 900 kg/m


There is an increasing imperative for psychologists and other behavioral scientists to understand how people behave on social media. However, it is often very difficult to execute experimental research on actual social media platforms, or to link survey responses to online behavior in order to perform correlational analyses. Thus, there is a natural desire to use self-reported behavioral intentions in standard survey studies to gain insight into online behavior. But are such hypothetical responses hopelessly disconnected from actual sharing decisions? Or are online survey samples via sources such as Amazon Mechanical Turk (MTurk) so different from the average social media user that the survey responses of one group give little insight into the on-platform behavior of the other? Here we investigate these issues by examining 67 pieces of political news content. We evaluate whether there is a meaningful relationship between (i) the level of sharing (tweets and retweets) of a given piece of content on Twitter, and (ii) the extent to which individuals  in online surveys on MTurk reported being willing to share that same piece of content. We found that the same news headlines that were more likely to be hypothetically shared on MTurk were also shared more frequently by Twitter users, r = .44. For example, across the observed range of MTurk sharing fractions, a 20 percentage point increase in the fraction of MTurk participants who reported being willing to share a news headline on social media was associated with 10x as many actual shares on Twitter. We also found that the correlation between sharing and various features of the headline was similar using both MTurk and Twitter data. These findings suggest that self-reported sharing intentions collected in online surveys are likely to provide some meaningful insight into what content would actually be shared on social media. Social media platforms such as Facebook and Twitter are now frequented by billions of people worldwide. It is no surprise, then, that there has been an increasing interest in investigating how people behave on social media, with many recent papers using sharing data from online platforms as real-world tests of a variety of important psychological theories –4. ThereFirst, studies using social media sharing data are typically observational in nature. This makes it hard to draw clear causal inferences about the relationships observed. It also largely excludes an entire range of studies aimed at exploring the impact of experimentally manipulating various features of the content or environment–most notably, studies trying to develop interventions to address problems on social media such as misinformation and hate speech . Privacy concerns typically prevent social media platforms from making demographic or other individual difference data available to researchers. The same concerns also often interfere linking data from more traditional surveys with respondents’ social media accounts. Such linking is, for example, a violation of the terms of service on Amazon’s Mechanical Turk (MTurk)–a frequent source for participants in psychological research –11.It would therefore be desirable to be able to investigate social media sharing in more traditional lab or online survey settings, rather than on-platform–and psychologists are increasingly engaging in such studies. For example, studies on fake news and misinformation have presented individuals with news headlines and asked online participants to indicate if they would be willing to share them on social media –16. It iThere are at least three reasons to expect that self-reported sharing intentions may not be a good proxy of sharing on-platform. First, individuals may lack insight into their own sharing behavior, such that their self-report of whether they would share content in the context of a survey might diverge from their actual decisions about what to share while on social media . Second,r = .47; specifically political content, r = .45), as well as an actual quantitative agreement ; and self-reports of Facebook sharing frequency also correlated with actual sharing frequency , although quantitatively people tended to substantially over-estimate their frequency of sharing. These data do not speak directly to our question of interest, however, as they examine retrospective description of aggregate behavior, whereas we are interested in participants’ forward-looking predictions about their future behavior.Empirical evidence evaluating these concerns is, to our knowledge, largely lacking. One somewhat-related piece of evidence comes from , who exaIn the current work, therefore, we investigate the extent to which social media sharing intentions elicited on MTurk provide insight into actual sharing on social media. In particular, we conduct our analysis at the headline level, and therefore avoid any privacy-related issues that may arise by conducting the analyses at the individual level. For a set of political news headlines, we compare the fraction of MTurk workers who say they would consider sharing the headline on social media with the number of times the headline was actually shared on Twitter . Our investigation is premised on the following claim: if self-report sharing intentions on MTurk provide useful signal about actual sharing behavior of the broader public, then the headlines that MTurkers say they would share more should actually receive much shares on Twitter. Here, we test this prediction.To assess MTurk sharing intentions, we analyzed sharing data from the control conditions of the two previous experiments of ours in which participants indicated their willingness to share a series of actual news headlines from social media related to American politics , 13  from [Mage = 37; 249 female, 232 male, 7 did not answer the gender question; 65.6% preferred Hillary Clinton over Donald Trump in a forced choice) from [We had data for 505 participants (ia) from  and for ce) from ; all werAs noted, participants were presented with a series of news headlines and asked whether they would consider sharing them on social media. The headlines were presented in ‘Facebook format’ . In , particith, 2019). The full set of headlines for [https://osf.io/b5m3n/.There were a total of 64 headlines that were presented to participants in , Study 2ines for  can be fhttps://osf.io/txf46/., ExperimThe instructions leading up to the sharing intentions task were somewhat different for the two experiments. In , particiIn , particiTo calculate our MTurk sharing variable, we calculated the fraction of participants saying they would share each headline in each of the two studies. For headlines that appeared in both studies, we then averaged across subjects in both studies.To determine the extent of actual sharing for each of the headlines, we used the Twitter search feature and searched for tweet IDs of all tweets between January 1, 2016 and March 5, 2019 that contained all of the words in a given headline. This time-period covers the first appearance of the earliest headlines in our data, and goes well beyond the first appearance of the most recent headline. Using this approach, we found at least one tweet for 68 of the 75 unique headlines across the two experiments. We then used the Twitter API to retrieve the number of retweets for each tweet ID. Finally, for each headline we determined the total number of shares by summing the number of tweets containing that headline and the number of retweets that each of those tweets received. We also recorded the date of the earliest tweet for each headline, allowing us to calculate the age of the headline.Participants provided informed consent, and our studies were approved by the Yale Human Subject Committee, IRB Protocol # 1307012383, the University of Regina Research Ethics Board, Protocol #2018–116, and by the MIT COUHES, Protocol #1806400195.r(66) = .47, p = .0001, such that headlines that MTurkers were more willing to share did indeed receive substantially more shares on Twitter. As can be seen in r(66) = .43, p = .0003, or only the number of retweets, r(66) = .46, p = .0001; to excluding headlines with 10 or fewer total Twitter shares, r(52) = .36, p = .0007; and to normalizing number of Twitter shares by the age of the headline , r(66) = .43, p = .0002. We also find similar results in a linear regression controlling for headline veracity when predicting Twitter sharing using the fraction of MTurkers who consider sharing the headline, β = .40, t = 3.12, p = .003. Finally, for 57 of the headlines, we also had a measure of the extent to which participants believed they had seen the headline previously. When including this familiarity measure as a control, as well as headline veracity, we continue to observe a significant positive relationship with the fraction of MTurkers who consider sharing the headline, β = .42, t = 2.82, p = .007.We begin by considering the correlation between the fraction of MTurk subjects who would consider sharing a headline and that headline’s Twitter sharing count . As predicted, we find a significant and large correlation, z-scored MTurk sharing intentions. We find a significant positive relationship, IRR = 1.918, z = 4.63, p < .0001. This finding is again robust to considering only the number of original tweets, IRR = 2.27, z = 4.65, p < .0001, or only the number of retweets, IRR = 1.58, z = 3.43, p = .0006; to excluding headlines with 10 or fewer total Twitter shares, IRR = 1.71, z = 4.59, p < .0001; and to including controls for headline veracity and headline age, IRR = 1.77, z = 3.04, p = .002, or controls for veracity, age, and prior familiarity among the 57 headlines for which familiarity data was available, IRR = 1.94, z = 3.35, p = .001. Equivalent results are also obtained using Poisson regression instead of negative binomial regression.To further demonstrate the robustness of this association, we use negative binomial regression to predict the number of Twitter shares as a function of r(66) = -0.536, p<0.001) and Twitter (r(66) = -.343, p = 0.004) compared to true headlines; headlines containing Moral words were shared less on both on MTurk (r(66) = -0.275, p = 0.023) and Twitter (r(66) = -0.317, p = 0.009); and there was no significant correlation between any of the other headline characteristics and sharing on either MTurk or Twitter . See Additionally, we compared the correlation between various headline characteristics and the likelihood of being shared on MTurk and Twitter. In addition to examining headline veracity, we used the Linguistic Inquiry and Word Count  dictionThe findings presented here suggest that self-reported sharing intentions collected on Amazon Mechanical Turk are likely to provide reasonable insight into what content would actually be shared on social media. Headlines that more MTurkers reported that they would considering sharing did in fact receive substantially more tweets and retweets on Twitter. This is an encouraging finding for social scientists interested in studying social media sharing in the context of traditional survey experiments.individual level. Thus, future work should investigate the link between self-reported and actual sharing at the level of the individual. Be that as it may, however, many of the important questions in this space are in fact headline-level questions . Fourth, the fact that we observe a substantial correlation between unmanipulated sharing intentions on MTurk and actual sharing on Twitter does not necessarily mean that the latter will respond to experimental manipulations in the same way as the former tweets a story receives on Twitter which are missing from our survey experiment. For example, the activity of bots; the social context of who shared the news story; and the sociopolitical context of the specific time at which the story was posted. If anything, however, the absence of these factors would deflate the observed correlation–thus our estimate provides a lower bound. Third, for logistical and privacy reasons, our analyses were conducted at the level of the headline rather than the individual. Thus, we did not observe whether the specific individuals who say they would share a given headline actually share that headline. As a result, we cannot draw conclusions about how intentions predict sharing at the example, )—for exaexample, . FinallyWe hope that the results reported here will contribute to the increasing study of online behavior by psychologists and other social scientists, and will inspire future individual-level methodological work on the validity of self-reported sharing intentions. Much of our social life is now conducted online, and understanding what motives sharing decisions on social media is an extremely important area for study using the lens of behavioral science.


Curved steel–concrete composite box beams are widely used in urban overpasses and ramp bridges. In contrast to straight composite beams, curved composite box beams exhibit complex mechanical behavior with bending–torsion coupling, including constrained torsion, distortion, and interfacial biaxial slip. The shear-lag effect and curvature variation in the radial direction should be taken into account when the beam is sufficiently wide. Additionally, long-term deflection has been observed in curved composite box beams due to the shrinkage and creep effects of the concrete slab. In this paper, an equilibrium equation for a theoretical model of curved composite box beams is proposed according to the virtual work principle. The finite element method is adopted to obtain the element stiffness matrix and nodal load matrix. The age-adjusted effective modulus method is introduced to address the concrete creep effects. This 26-DOF finite beam element model is able to simulate the constrained torsion, distortion, interfacial biaxial slip, shear lag, and time-dependent effects of curved composite box beams and account for curvature variation in the radial direction. An elaborate finite element model of a typical curved composite box beam is established. The correctness and applicability of the proposed finite beam element model is verified by comparing the results from the proposed beam element model to those from the elaborate finite element model. The proposed beam element model is used to analyze the long-term behavior of curved composite box beams. The analysis shows that significant changes in the displacement, stress and shear-lag coefficient occur in the curved composite beams within the first year of loading, after which the variation tendency becomes gradual. Moreover, increases in the central angle and shear connection stiffness both reduce the change rates of displacement and stress with respect to time. Curved steel–concrete composite box beams have gradually become one of the main design types for urban overpasses and ramp bridges due to their light weight, high torsional rigidity, and rapid construction. However, in contrast to straight beam bridges, typical bending–torsion coupling mechanical behavior can be found in curved beam bridges . Hence, For the numerical analysis of curved beams, the use of a three-dimensional finite element model can accurately simulate its mechanical behavior. However, this modeling and analysis process is complex and requires high computer performance, and the calculation efficiency with a three-dimensional model is not as good as that with a one-dimensional model. The study of one-dimensional theoretical models of curved beams first began in the 1960s. Vlasov  establisThe time-dependent (shrinkage and creep) effects of concrete have a significant influence on the mechanical behavior in steel–concrete composite beams. Due to the effects of concrete shrinkage and creep, the deformation of the structure under long-term loads is often much greater than that under short-term loads. The long-term deflection of composite beams has become a key issue for composite beam design and analysis. The authors of Reference  developeThe shrinkage behavior of concrete is not related to its stress state; thus, shrinkage can be easily achieved by applying an initial strain to the model. The creep behavior of concrete is directly related to the stress state of concrete. Research on the long-term behavior of composite beams began in the 1970s. Bazant et al. , and theBased on the Vlasov’s one-dimensional theoretical model of curved beams, this paper introduces a torsional warping function, a distortional angle, an interfacial longitudinal and an interfacial transverse sliding function, and a shear-lag intensity function for concrete slabs and a shear-lag intensity function for steel beams and adopts the age-adjusted effective modulus method to analyze the effects of concrete creep. Moreover, this study establishes a finite beam element for curved composite box beams that can consider constrained torsion, distortion, shear lag, interfacial biaxial slip, time-dependent effects, and curvature variation in the radial direction. Finally, this study analyzes the long-term mechanical behavior of curved composite box girders by use of the developed finite beam element model.The basic hypotheses made in the derivation process in this paper are as follows: (1) The sections of the concrete slab are rectangular, and the slab’s curvature is the same as that of the undeformed structure; (2) the vertical displacements of the concrete and the steel beam are the same; (3) the curvature radius of the composite beam does not change along the length of the beam; (4) the stiffness of the shear connections of the composite beam is uniformly distributed in the longitudinal and transverse directions; (5) the shear stress produced by the distortional effect is ignored; (6) shear deformation produced by bending and distortional warping is ignored; and (7) the shear-lag effect is taken into account under vertical bending.oxyz is a three-dimensional flow coordinate system that passes through the centroid line, the ox-axis is parallel to the concrete slab and points to the curvature center of the box beam, the oy-axis is straight downward, and the oz-axis coincides with the undeformed axis of the beam. Moreover, the tangential directions of every thin-walled bar in the sections of the box beam are set as the s-axis, and the normal directions of every thin-walled bar in the sections of the box beam are set as the n-axis.The geometric dimensions and coordinate system of the curved composite box beam are shown in ox, oy, and oz axes of the centroid of the curved composite box beam are denoted u(z), v(z), and w(z), respectively. The torsion angle around the torsion center and the distortion angle around the distortion center are denoted θ(z) and θd(z), respectively. The transverse and longitudinal slip of the steel beam and concrete slab are denoted kaΩx(z) and kaΩs(z), respectively, where k is s or c, which represent the steel beam or concrete slab, respectively; as = 1 and ac = −1; and Ωx(z) and Ωs(z) are the transverse and longitudinal slip functions, respectively. According to Ullmanski’s second torsion theory, an independent function of torsional warping displacement, β(z), is introduced. Additionally, kf  is the shear-lag warping strength functions that represent the steel beam or concrete slab. Based on the coordinate system shown in zkW, tangential displacement skW, and normal displacement nkW at any point of the composite box beam can be obtained as follows:k0 = 1/R0 is the initial curvature of the centroid line of the box beam sections; R0 is the curvature radius of the centroid line of the box beam sections; α is the angle from the x-axis to the n-axis, which is anticlockwise positive; ω and ωd are the torsional warping and the distortional warping principal polar coordinates, respectively; and kψ(x) is the shape function for the shear-lag warping of the concrete slab or steel beam, the expressions of which are as shown in The displacements along the Transformed sections should be adopted for calculating geometric characteristics. For the calculation of the axial and bending characteristics of the composite beam, the thickness of the concrete slab is unchanged, whereas the width decreases. For the calculation of torsional and distortional effects of the composite beam, the width of the concrete slab remains unchanged, whereas the thickness decreases.xs, ys) and  are the coordinates of the torsion center, S, and the distortion center, D, of the transformed sections of the composite beam, respectively; h1 and h3 are the vertical distances from the distortion center to the top and bottom plates, respectively; and h2 and h4 are the vertical distances from the distortion center to the left and right webs, respectively.In addition, according to the literature ,20, in Eas is 1 for the steel beam and −1 for the concrete slab. According to Equations (1) and (2), the relative slips on the interface between the steel beam and concrete slab are expressed as follows:usp and wsp denote the transverse and longitudinal interfacial slip, respectively.Note that P, in the three-dimensional flow coordinate system is expressed as follows:Based on the abovementioned displacement mode, according to the curved shell theory and taking the curvature variation in the radial direction of the beam into consideration, the normal strain component at any point, P, of the cross-section is expressed as follows:r* denotes the vertical distance between the torsion center and the tangent line of point, P.According to Hypothesis (5), based on the curved shell theory, the shear strain component at any point, kB are 11 × 23, and its exact value is given in S and displacement vector d are expressed as follows:The equilibrium equation for a curved steel–concrete composite beam can be derived according to the virtual work principle as follows:σs and τs are the normal stress and shear stress of the steel beam, respectively; Es is the elastic modulus of steel; and μs is the Poisson’s ratio of steel.When the bridge is in use, the steel beam is in the elastic phase, and the stress–strain relationship of the steel beam is expressed as follows:To take the effects of concrete shrinkage and creep into consideration, the stress–strain relationship of the concrete slab can be expressed as follows:t0 is the initial loading age; μc is the Poisson’s ratio of concrete; J is the concrete creep function at time t; σc and τc are the normal stress and shear stress of the concrete slab, respectively; Ece is the concrete age-adjusted effective elastic modulus; and ξ is the influence factor of the creep effects. Ece and ξ can be calculated by Equations (24) and (25), respectively.Ec(t0) is the concrete elastic modulus at time t0, φ is the concrete creep coefficient, and χ is the concrete aging coefficient, which can be derived from Equation (26).R is the concrete relaxation function, which can be calculated according to the literature 23 × 26 is introduced into Equation (12), and the shape function matrix [NF]10 × 26 is introduced into Equation (36); both of the shape function matrices are shown in N and NF into Equation (9), the finite beam element equation for the curved composite box beam can be derived as follows:The shape function matrix [K]26 × 26 in Equation (39) is the element stiffness matrix, which can be calculated as follows:TR]23 × 23 is the distortion-resisting stiffness matrix of the frame, in which TR = KR and the other elements are 0, and le is the length of the finite beam elements.[F]26× 1 in Equation (39) is the equivalent load vector of the node, which can be calculated as follows:Fq is the equivalent load vector of the node caused by external loads, which can be calculated by Equation (42); Fξ is the equivalent load vector of the node caused by the concrete creep effect, which can be calculated by Equation (43); and Fsh is the equivalent load vector of the node caused by the concrete shrinkage effect, which can be calculated by Equation (44).[Notably, the calculation methods for the characteristic geometrical parameters of the section under torsion and distortion in the finite beam element model can be found in the literature ,23.ρu and ρw, are both equal to 100 N/mm3; and a vertical load of 10 kN/mm acts at the section centroid line.The proposed finite beam element model is applied to calculate the long-term behavior of a typical curved composite box beam. The cross-section and load layout of the curved composite box beam are shown in The boundary conditions of the beam element model are as follows: At the mid-span, the longitudinal displacement and the longitudinal slip between the concrete slab and steel beam are all restrained to ensure symmetrical structural boundary constraints; at both ends of the beam, the transverse displacement, transverse slip, deflection, and torsion angle are restrained; and at the position of every diaphragm, the distortion angle is restrained.The elaborate finite element model of a curved steel–concrete composite box beam is established in ANSYS. The concrete slabs, steel beams, and transverse diaphragms are modeled with Shell181 elements, whereas the shear connectors are modeled with Combin14 elements. The finite element model is shown in Es and Poisson’s ratio of steel μs are 2.06 × 105 MPa and 0.3, respectively; the calculation of the creep behavior of concrete in the two models use the age-adjusted effective modulus method; and the Poisson’s ratio of concrete μc is 0.2. The elastic modulus formula and the shrinkage creep model are obtained within CEB-FIP90 [t0 is 28 days. Using the finite beam element model and the elaborate finite element model, time-dependent changes in the deflection, transverse displacement, and stress of the curved composite box beam were calculated from the loading age to 3000 days, as shown in The parameters of the material and environment of the proposed beam element model and the elaborate finite element model established in ANSYS are as follows: The elastic modulus of steel EB-FIP90 ; the dryAccording to the three figures, the deflection and transverse displacement of the curved composite box beam increase over time due to concrete shrinkage and creep, and the compressive stress in the concrete decreases over time, whereas the tensile stress in the steel beam increases over time. Within 250 days after loading, the displacement and the stress of the curved composite box beam change significantly with respect to time, and then the growth rate slows and becomes gradual after the first year. The results show that the influence of concrete shrinkage and creep is significant in the early loading stage, whereas this influence is very small after the first year.λ, is introduced to reflect the influence of the shear-lag effect of curved composite beams. The shear-lag coefficient, λ, is defined as ratio of the stress at the intersection of the web and flange to that at the same location when the shear-lag effect is ignored. Based on the curved composite box girder in The shear-lag coefficient, The initial central angles are set as 0°, 30°, and 60°, based on the curved composite box girder in It can be concluded that the growth rate of displacement, caused by concrete shrinkage and creep effect, becomes small with the increase in the initial curvature of the curved box girder. The tensile stress growth rate of the steel girder decreases gradually with increasing initial curvature. The compressive stress reduction rate of the concrete slab decreases gradually with increasing initial curvature.3. According to the proposed finite beam element model, the deflection and transverse and longitudinal displacement distributions along the span of the curved composite box girder at the initial and ultimate loading ages are calculated, as shown in 3, respectively, due to the influence of concrete shrinkage and creep. Moreover, for shear connection stiffness values of 0.1, 1, and 10 N/mm3, the maximum growth rates of transverse displacement are 116.1%, 67.2%, and 49.2%, respectively, whereas the maximum growth rates of longitudinal displacement are 86.9%, 75.8%, and 71.3%, respectively. 3, respectively, due to the influence of concrete shrinkage and creep. Under these same stiffness values, the compressive stress reduction rates at the inside of the concrete slab are 44.6%, 59.4%, and 57.1%, respectively.The curved composite box girder in It can be concluded that the growth rate of displacement, which is caused by concrete shrinkage and creep, becomes small as the interfacial shear connection stiffness of the curved composite box girder increases. The tensile stress growth rate of the steel girder decreases with increasing interfacial shear connection stiffness. The compressive stress reduction rate of the concrete slab becomes large with increasing interfacial shear connection stiffness.(1) Based on the Vlasov’s one-dimensional theoretical model of curved beams, a torsional warping function, a distortional angle, transverse and longitudinal slip functions, a shear-lag intensity function for the concrete slab, a shear-lag intensity function for the steel beam, and constitutive relationships for concrete shrinkage and creep were introduced. The variation of the curvature in the radial direction was also taken into account. The equilibrium equation for the curved composite box beam was proposed according to the virtual work principle. Then, the stiffness matrix and equivalent nodal load vector of the two-node finite beam element with 26 DOFs, which analyzes the long-term behavior of curved composite box beams, were obtained by adopting the finite element method and the age-adjusted effective modulus method.(2) An elaborate finite element model of a typical curved composite box beam was established. The correctness and applicability of the two-node finite beam element with 26 DOFs were verified through a comparison of the results from the finite beam element model and those from the elaborate finite element model.(3) The proposed finite beam element model was adopted to analyze the influence of the concrete time-dependent effects on the long-term behavior of curved composite box beams. The analysis shows that significant changes of the displacement, stress, and shear-lag coefficient occur in the curved composite beams within the first year of loading, due to the time-dependent effects of concrete, after which the variation tendency becomes gradual.(4) The proposed finite beam element model was adopted to analyze the influence of the concrete shrinkage and creep effects on the long-term behavior of curved composite box beams under different central angles and shear connection stiffness. The results show that increases of the central angle and the shear connection stiffness reduce the change rates of both displacement and stress, with respect to time.


A wide variety of regulators have been identified in mechanistic target of rapamycin (mTOR) activation; however, the protective mechanisms of mTOR inactivation are still largely unknown, especially in tumor growth. Here, we have found the hepatocyte growth factor (HGF) receptor (MET) is required for mTOR activation‐stimulated mitochondrial oxidative phosphorylation (OXPHOS) in a phosphorylation‐dependent manner in liver cancer. Intriguingly, we observed mitochondrial quality dictates the regulatory effects of MET on mTOR and OXPHOS. Once overloaded, mitochondrial reactive oxygen species (ROS) inhibits mTOR activity and OXPHOS performance to prevent mitochondrial dysfunction‐induced tumor cell death, by disrupting MET dimerization to block its autophosphorylation and interaction with vacuolar ATP synthase (V‐ATPase). The MET‐mTOR‐ROS loop acts as a protective checkpoint in liver cancer, and thus this autoregulatory machinery is a promising combinational target for liver cancer therapy. AAamino acidsHGFhepatocyte growth factorKDkinase‐deadKOknockoutmTORmechanistic target of rapamycinMETHGF receptorNACN‐acetyl‐L‐cysteineOXPHOSoxidative phosphorylationRedoxoxidation‐reduction reactionROSreactive oxygen speciesS6K1ribosomal protein S6 kinase 1TPR‐METtranslocated promoter region fused to METV‐ATPasevacuolar ATP synthaseWTwild‐typeDear Editor,Hyperactivation of mechanistic target of rapamycin (mTOR) signaling is frequently observed in cancer and aging.We observed amino acids (AA)‐enhanced phosphorylation of the ribosomal protein S6 kinase 1 (S6K1), a biomarker of mTOR activation, was repressed in MET knockout (KO) HepG2 cells. This phenomenon could be rescued by forced expression of wild‐type (WT) MET . In support of this, the MET inhibitor Capmatinib exhibited near‐total inhibition of S6K1 phosphorylation . Furthermore, we found reintroduction of a kinase‐dead (KD) MET mutant was unable to rescue MET KO‐caused mTOR inactivation , while a constitutively active translocatedpromoter region fused to MET (TPR‐MET) mutant enhanced AA‐stimulated S6K1 phosphorylation , suggesting MET mediates AA–mTOR signaling pathway in a phosphorylation‐dependent manner.Liver‐KO) . We subsequently found HGF greatly enhanced AA‐stimulated OXPHOS , and only WT MET could restore functional defects induced by MET KO . Using the vacuolar ATP synthase (V‐ATPase) inhibitor Concanamycin A and the mTOR inhibitor Rapamycin, we further demonstrated effects of MET on OXPHOS were dependent on the V‐ATPase–mTOR axis .Interestingly, AA‐stimulated mitochondrial oxidative phosphorylation (OXPHOS), including oxidation‐reduction reaction  and ATP production , was severely compromised in MET KO cells. Parallel impairments were observed in mice with liver‐specific MET deficiency  and its phosphorylation . Consequently, OXPHOS dysfunction disrupted the MET–ATP6V1A interaction  and AA‐stimulated mTOR activation . Both HGF and TPR‐MET exacerbated OXPHOS dysfunction‐caused cell death, which could be largely rescued by the inhibition of V‐ATPase or mTOR . Reconstitution assays in MET KO cells also showed only WT MET exacerbated cell death caused by dysfunctional OXPHOS . Briefly, OXPHOS dysfunction propels a feedback to prevent persistent mTOR activation‐caused impairment.N‐acetyl‐L‐cysteine (NAC) efficiently restored the impairment of mTOR activation in a MET‐dependent manner  scavenger  Figures . NAC cou Figures . Moreove Figures . FurtherAtg5 , or chemical disruption of autophagy flux by Bafilomycin A1 , which suggested autophagy has no influences on MET‐controlled mTOR activation. We further explored the impacts of autophagy on the ROS‐driven feedback loop, and results showed even under autophagy deficiency, MET still could facilitate AA‐stimulated mTOR activation  and OXPHOS ; moreover, OXPHOS dysfunction‐caused ineffectiveness of MET regulation still could be rescued by NAC. This suggests autophagy is not involved in mitochondrial ROS suspending MET‐mTOR‐OXPHOS axis.Notably, overexpression of MET could promote AA‐stimulated mTOR activation even in autophagy deficient condition caused by genetic deletion of To investigate the pathological significance of MET‐mTOR‐ROS loop in tumor growth, we firstly analyzed the impacts of mTOR inhibition and ROS elimination on MET deficient cancer cells in vitro. WT and MET KO HepG2 cells were individually treated with NAC or NAC plus Rapamycin, and results indicated significant synergistic effects of MET and mTOR on the proliferation , viability , and colony formation  of cancer cells under ROS clearance. The similar tendencies were also found in Capmatinib‐treated MET‐driven TPRMET‐NIH3T3 cell line .To determine whether the MET‐mTOR‐ROS loop is a viable therapeutic target in liver cancer, we constructed multiple mouse models Figure . In accoLiver‐KO mice individually received Rapamycin or/and NAC . Results suggested Rapamycin significantly decreased, while NAC obviously increased, liver weight in MetLiver‐KO mice . Supporting this, the hepatocytes isolated from the mouse models showed consistent changes in cell viability . Furthermore, WT and MetLiver‐KO mice were used to investigate the impact of MET‐mTOR‐ROS loop on mice survival . Results indicated the enormous role of Rapamycin in extending, and conversely NAC in reducing, the overall survival of MetLiver‐KO mice .Additionally, to evaluate the physiological role of the MET‐mTOR‐ROS loop in liver development, WT and MetIn conclusion, we have identified herein that MET as a central component of the mTOR sensing machinery in liver cancer. MET is required for AA‐stimulated mTOR activation and mitochondrial OXPHOS in a phosphorylation‐dependent manner. Mitochondrial quality in turn dictates MET phosphorylation status and its binding to V‐ATPase. Once overloaded, mitochondrial ROS inhibits mTOR activity and OXPHOS to avoid mitochondrial dysfunction‐induced tumor cell death, by targeting MET dimerization with disruption of its phosphorylation and interaction with V‐ATPase. We provide a schematic model to illustrate the MET‐dependent homeostatic maintenance between mTOR activation and OXPHOS . Through integrating signals of AA and ROS, the MET‐mTOR‐ROS loop plays a protective checkpoint‐like role in liver cancer. We therefore propose this autoregulatory machinery is a promising combinational target for liver cancer therapy. Notably, the indeterminate influence of ROSThe authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.Xing Huang, Xueli Bai, and Tingbo Liang conceived the project and supervised the study. Xing Huang designed and conducted the major experiments, Gang Zhang helped for metabolic assay, and all authors were involved in data analysis and interpretation. Xing Huang and Gang Zhang wrote and revised the manuscript, other authors discussed and commented on the manuscript, and all authors approved the final manuscript version. Xing Huang and Gang Zhang contributed equally to the drafting process. Xing Huang, Xueli Bai, and Tingbo Liang share senior authorship.The mice experiments performed in this study were approved by Ethnics Committee of Southeast University.All the authors consent for publication.Supporting FigureClick here for additional data file.Supporting FigureClick here for additional data file.Supporting InformationClick here for additional data file.


Antibiotic-loaded polymethyl methacrylate (PMMA) has been widely applied in the treatment of knee periprosthetic joint infections. However, problems with antibiotic-loaded PMMA-based spacers, such as structural fracture and implant dislocation, remain unresolved. A novel polyethylene-based spacer, designed with an ultra-congruent articulating surface and multiple fenestrations, was introduced in the current study. Validation tests for biomechanical safety, wear performance, and efficacy of antibiotic cement were reported. During cycle fatigue testing, no tibial spacer failures were observed, and less wear debris generation was reported compared to commercial PMMA-based spacers. The volumetric wear of the novel spacer was within the safety threshold for osteolysis-free volumetric wear. An effective infection control was demonstrated despite the application of lesser antibiotic cement in the 30-day antibiotic elution test. The tube dilution test confirmed adequate inhibitory capabilities against pathogens with the loaded antibiotic option utilized in the current study. The novel polyethylene-based knee spacer may offer sufficient biomechanical safety and serve as an adequate carrier of antibiotic-loaded cement for infection control. Further clinical trials shall be conducted for more comprehensive validation of the novel spacer for practical application. Ultra-high molecular polyethylene (UHMWPE) and polymethyl methacrylate (PMMA)-based bone cement are polymers commonly utilized in joint arthroplasty surgeries. Bone cement has generally been utilized for gap filling or reinforcement of an osteoporotic structure, while UHMWPE has been widely applied in soft bearing components for artificial joint articulation. Total knee arthroplasty (TKA) is currently accepted as the most efficient and successful surgical strategy for the treatment of intracapsular disease of the knee joint, greatly enhancing patients’ quality of life ,2. HowevAlthough articulating knee spacers have demonstrated advantages in joint mobility and clinically successful rates in infection control, issues relating to biomechanical safety contributed by cement material characteristics should be carefully noted. Articulating knee spacer-related complications include squeaking during articulation , intra-aA novel polyethylene-based knee spacer, for the purpose of infection control, was developed to enhance the biomechanical safety and surgical convenience of articulating knee spacers. As an antibiotic-loaded cement carrier, the scaffold-like structures within the polyethylene component facilitate cement deposition with antibiotic-releasing properties, while a standardized metallic canal rod is prepared for intramedullary infection control. The current pre-clinical validation study has been designed to confirm the safety and efficacy of the novel device in infection control by conducting the required in vitro biomechanical fatigue, wear, and antibiotic elution testing before approval in clinical applications.The novel spacer set consists of a femoral spacer, a tibial spacer and a canal rod . The spaThe canal rod is made of a titanium alloy consisting of a 4 mm shaft, a proximal instrument adapter to facilitate the removal of the rod from the canal, and a distal umbrella-shaped hook to ensure distal support of the wrapped cement to facilitate the clean removal of the structure from the canal when infection control has been successfully accomplished .Size #1 femoral and tibial spacers were selected based on the worst-case principle (the least space spared for antibiotic-loaded cement volume among the 5 sizes) and the available dimensions of the comparative commercial spacer. Antibiotic-loaded bone cement  was applied to validate the usage of commercial cement in infection control, while regular (non-antibiotic) bone cement  was utilized as a cement baseline for antibiotic elution testing. The femoral and tibial spacers were positioned inside customized silicone molds to ensure smooth articulating surfaces during cement preparation . The cem5 cycles”, to mimic the maximum 180-day implantation period for general infection control [Fatigue testing was set in accordance with the guidance in ASTM F1800 A. Both s control . The tes5 cycles [The wear test was conducted according to the guidance in ISO 14243-1. The loading magnitudes were reduced to 50% to account for partial weight bearing conditions and the regular 180-day usage of the knee spacer . Hence, 5 cycles , as desc® knee simulator, Endolab Mechanical Engineering GmbH, Riedering, Germany, 5 cycles were conducted with loading frequency set at 1 Hz for all 6 specimen sets. All specimens were then dried in a vacuum chamber (37 °C) to facilitate the quantification of the material loss due to spacer or cement wear. The results were compared to published data on commercial knee spacers to confirm the wear safety volume [All specimens were pre-soaked in the test fluid . The specimens were then mounted onto the knee simulator  (ATCC 25923), methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 43300), coagulase-negative Staphylococci (CoNS) (ATCC 14990), Pseudomonas aeruginosa (P. aeruginosa) (ATCC 27853), and Escherichia coli (E. coli) (ATCC 25922) were selected as the pathogens. The samples were added to a tube with 105 bacterial colony forming units (CFUs)/mL in 96-well cultured dishes and incubated at 37 °C for 24 h. Visual identification of bacterial growth was used as qualitative evidence of bacterial inhibition. Clear test fluids were an indication of sufficient eluted antibiotic concentrations. A positive control (without antibiotics) and standard samples with varying antibiotic concentrations were prepared for visual comparison.The retrieved 2 mL elution samples were measured for antibiotic activities with the tube dilution method. Bacteria strains, including methicillin-sensitive 5 fatigue load cycles. The maximal displacement of material remained stable without sudden raise/drop of values recorded by the material testing system. However, one test specimen showed minor cracks on the cement region  revealed high elution behaviors at the beginning  which gradually decreased with time . The oveP. aeruginosa throughout a 30-day testing period with observations of clear tube samples. Antibiotic activities lasted for 24 days in E. coli samples, and 3 days in MRSA samples. However, the effective bacterial inhibition of CoNS samples only lasted for one day.Polymer materials have been widely applied in orthopedic surgery for the purpose of implantation or supplementation. The novel polyethylene-based knee spacer is the first design concept using scaffold-like UHMWPE structures filled with antibiotic–loaded PMMA-based bone cement, to facilitate smoother articulation and control infection of the knee joint. The current study conducted several in vitro pre-clinical validation tests to validate the safety and efficiency of the spacer set. The advantageous material characteristics of UHMWPE supported the fatigue safety of the tibial spacer and ideal anti-wear performance for spacer longevity in simulated knee motion while ensuring sufficient antibiotic elution performance.Safety is always the key issue in orthopedic implants. Commercial preformed knee PMMA cement spacers or hand-made cement spacers have been widely used in two-stage exchange arthroplasty. However, spacer dislocation and fracture are common complications. Haddad et al.  reported3. According to the wear testing results in the current study, the dry weight loss of the polyethylene-based spacers was less than that of the commercial cement spacers  [3), was only 55.92 mm3, lower than the reported osteolysis-free volumetric wear threshold. The ideal surface condition of UHMWPE spacers , which may have contributed to the volumetric wear results, demonstrated better anti-wear performance than commercial knee spacer with full-cement coverage.Component wear at the articulating surface remains an issue as there are no existing surface treatment and there remains uncontrollable complexity within the joint capsular. In addition to structural damage due to surface wear, polymer and cement wear debris morphology ,38,39,4026.0 mg) . The volE. coli. The major reason may be the bone cement used in the current study, which was loaded with specific gentamicin concentrations that may not be appropriate antibiotic options or dosages against these pathogens. This reveals an important consideration that not all commercial preformed antibiotic-loaded cement spacers or their associated antibiotic formulations may fulfill ideal antibiotic options for infection control. Therefore, flexible antibiotic options  and 71.6% of the tibial  spacers. A reduced cement volume usage can provide better cost-effectiveness. However, major concerns exist with insufficient antibiotic elution concentration associated with lesser antibiotic-loaded cement usage. However, the current study results for the novel scaffold-like UHMWPE spacer have provided sufficient confidence that lesser cement volume usage may still provide clinically effective infection control capabilities with minimum gentamicin concentrations in the antibiotic-loaded cement group (1.9 μg/mL) remaining effective (>1 μg/mL)  at the e-Concern of Bacterial BiofilmThere were several limitations with the current study:The formation of bacterial biofilm is an important concern when foreign orthopedic devices are implanted , especia-The Antibiotic-Loaded Cement AppliedThe current study has only considered a single antibiotic-loaded cement option for tibial spacer fatigue, wear, and antibiotic-elution testing. The application of the current spacer with other commercial antibiotic cements or surgeon-defined antibiotic formulations or dosages will have to be further validated for mechanical safety and biological efficacy concerns. In addition, the Palacos R + G (0.5 g gentamycin/40 g powder) is generally applied for prophylaxis use . Due to -Modified Test ConditionThe spacer is defined as a device used for temporary infection control and limb length (or soft tissue tension) maintenance. Generally, the recommended period for usage is 180 days under partial weight-bearing conditions. The load conditions in the current biomechanical test were modified with reference to an estimated partial weight-bearing condition . These t-Wear Rate CalculationDue to technical limitations, the weight or volumetric ratio of the UHMWPE and cement wear debris could not be identified. However, from wear pattern observations of the test specimens and SEM images for particle examination, most of the wear particle were determined to have originated from the UHMWPE material. Volumetric wear performance was then calculated by applying the appropriate density for UHMWPE.-Surface Condition and Material of Molding DeviceIt was observed that the cement articulation was not ideally smooth. The major cause of this rough surface was the simple silicone mold was utilized for forming the articulating surface . The sil-Unverified Canal RodThe canal rod in the current knee spacer set has only been introduced for its function and features but was not involved in the pre-clinical validation testing. Major safety and efficacy concerns exist with the utilization of the worst-case conditions, without the utilization of canal rod (wrapped with antibiotic cement). No fatigue testing was applied to the canal rods as they do not contribute to mechanical support. Antibiotic elution testing and wear testing were also not applied as the canal rods did not interfere with the antibiotic-loaded cement spacer and its articulation surface.The scientific validation conducted in the current study with a novel scaffold-like polyethylene-based knee spacer design will provide surgeons with an improved knee joint infection control solution that has sufficient mechanical properties, anti-wear performance, and antibiotic elution. As a cement carrier, this novel device may offer surgeons more flexible antibiotic options and dosage adjustments for a more precise and effective infection control. Further clinical trials should be conducted to enhance clinical confidence regarding the use of this device in practical applications. TW M465151U  Porous artificial knee joint CN203341865U Porous type artificial knee joint (patent of Mainland China)


Antibiotic resistance is an emerging problem caused due to antibiotic use. In countries with high rates of infectious diseases, antibiotic resistance is a frequent cause of mortality. The aim was to analyse antibiotic prescribing practices between 2008 and 2017 in a teaching (TH) and a non-teaching (NTH) hospital, as typical hospitals of low- and middle-income countries, and to compare antibiotic prescribing for severe infectious indications for which empiric antibiotic treatment is recommended.P-values < 0.05 were considered significant.Data from adult patients registered at two Indian private-sector hospitals with one of the following indications: epiglottitis, pneumonia, peritonitis, pyelonephritis, cellulitis, erysipelas, septic arthritis, endocarditis, meningitis or sepsis; were included and analysed. Antibiotic prescription data was analyzed using the World Health Organization’s (WHO) Anatomical Therapeutic Chemical classification system and the Defined Daily Doses. Chi-square and linear regression were used to compare the data between groups. Time series analyses were conducted using linear regression. access category of antibiotics (i.e. the first-choice of treatment according to the WHO). The WHO’s second-choice of treatment, the watch category, comprised 29 and 40% of total prescriptions in the TH and NTH, respectively. Prescribing of fixed-dose combinations (FDCs) of antibiotics was significantly higher in the NTH (18%) than in the TH . Prescribing of watch antibiotics and FDCs increased significantly in both hospitals between 2008 and 2017 among patients with pneumonia, cellulitis and peritonitis (P < 0.05).In total, 3766 patients were included, 2504 inpatients in the NTH and 1262 in the TH, of which 92 and 89% patients, respectively, were prescribed antibiotics. Sixty-one percent of total prescriptions in the TH and 40% in the NTH comprised the watch antibiotics and FDCs of antibiotics increased over time at both hospitals, indicating under prescribing of access antibiotics and more prescribing of second-choice antibiotics. The results can be used to highlight the areas of improvement in similar settings. Implementing diagnostic routines and local prescribing guidelines could improve the prescribing practices.Prescribing of  Antibiotic resistance is an emerging global threat, as it causes significant morbidity and mortality worldwide , 2. In aIn low- and middle-income countries (LMICs), the infectious disease burden is often high, and antibiotic resistance is one of the common causes of mortality among patients with infectious diseases , 5. TackImproper use of antibiotics contributes to the development of antibiotic resistance. As reported previously, antibiotics should be prescribed only for relevant indications . FurtherThe study population was inpatients admitted to the study hospitals, with severe infections for which empirical antibiotic treatment is recommended . The hosThis prospective study with time-series analyses was conducted at two tertiary care, private sector hospitals run by the same trust, located in Ujjain district of Madhya Pradesh, India, one teaching hospital (TH) and one non-teaching (NTH). The TH is in a rural area and has 800 beds and the NTH is centrally located with 400 beds. At the TH, patients are provided medical services and medicines free of charge while medical services at the NTH are charged but at a reduced level . At the access, watch and reserve antibiotic categories . J0. J015]. P < 0.01, Table P < 0.01 for both antibiotic groups, Table watch and FDCs (J01R) increased from 2008 to 2017 while prescribing of reserve antibiotics decreased. At the TH, prescribing in DDDs per 1000 patient days, of access, watch and FDCs decreased from 2008 to 2017  group was commonly prescribed, which is adherent with guidelines . In the 17 Table .access, watch and FDC of antibiotics rose in the NTH, and prescribing of watch, reserve and FDCs increased in the TH.According to our knowledge, this is the first study that compares antibiotic prescribing practices for selected infectious diagnoses over a 10 years period in two Indian private-sector hospitals. In the NTH, prescribing of antibiotics for all indications, including antibiotics specifically for cellulitis, pneumonia, peritonitis and sepsis diagnoses, increased from 2008 to 2017. In the TH, although antibiotic prescribing practices did not change during the study period, antibiotic prescribing for cellulitis, pneumonia and peritonitis increased and decreased for sepsis. Between 2008 and 2017, prescribing of In this study, we analysed adherence to various international recommendations for antibiotic prescribing: the WHO’s recommendations for empirical antibiotic treatment for cellulitis and pneumonia, the recommendations for empirical antibiotic treatment from the ‘Surviving sepsis campaign’ for sepsis and the recommendations of the World Society of Emergency Surgery for peritonitis , 18, 19.Guidelines on empirical antibiotic treatment are often based on whether an infection is healthcare associated or community acquired. As both bacterial flora and susceptibility patterns vary worldwide, the following factors are important to consider while selecting the most appropriate antibiotic: the bacterium most likely to be the cause of the infection, patient’s clinical status, allergies to specific antibiotics and current or previous antibiotic resistance and responses to antibiotic treatment , 18, 19.In the NTH, the FDCs of antibiotics (J01R) were commonly prescribed to all patients, including those with cellulitis, peritonitis, pneumonia and sepsis. In contrast, the FDCs were less frequently prescribed in the TH. Prescribing of the FDCs for all indications increased in the TH during the study period but decreased for diagnoses of pneumonia and sepsis. Prescribing FDCs of antibiotics is not recommended, as they have been shown to drive antibiotic resistance, a common consequence of unnecessarily prescribed antibiotics, often in incorrect doses . Appropraccess antibiotics should primarily be used to save, whereas watch and reserve antibiotics should be used only for specific and limited indications in critically ill patients or patients with infections caused by bacteria with known antibiotic resistance [reserve antibiotics comprised less than 1% of the total antibiotics prescribed. In the TH, access antibiotics were most commonly prescribed (61% of antibiotics prescribed), followed by watch antibiotics (29%). However, in the NTH, access and watch antibiotics were prescribed in equal numbers (40% each). These results indicated that watch antibiotics accounted for a higher proportion of antibiotics prescribed in the NTH than in the TH. Furthermore, in the TH, prescribing of watch and reserve antibiotics for cellulitis or peritonitis increased in both hospitals during the study period, whereas prescribing of these antibiotics for sepsis decreased.Regardless of the country or setting, sistance . In bothaccess, watch and reserve categorization of antibiotics provides a practical guide for proper antibiotic prescribing and can provide a basis for the development of local prescribing guidelines [As noted earlier, the lack of microbiological analyses makes it difficult to comment on the rationale underlying the antibiotic prescription practices in the two hospitals. Nevertheless, the prescribing practices can be considered in terms of international recommendations on antibiotic aimed at reducing the emergence of antibiotic resistance. Based on the results of the present study, greater adherence to international guidelines for empirical antibiotic treatment is needed at both hospitals to optimize antibiotic use. The idelines .The relatively low incidence of some infectious diseases, such as infective endocarditis, among admissions to the NTH and the TH may be explained by underdiagnosing, which is a major problem in hospitals, as described in a previous study on infective endocarditis in India . In manyaccess, watch and reserve, as well as existing guidelines on empirical prescribing for each diagnosis, the appropriateness of antibiotic prescribing practices in both hospitals could be assessed. Finally, this study included only adult patients. The reasons for this were two-fold: First, the ‘defined daily dose’ system is based on adult patients. Thus, antibiotic use among paediatric patients cannot be evaluated using the defined daily dose system. Second, the recommendations used to assess rationality in antibiotic prescribing in this study were for adults only.A strength of this study is the data collection design. The hospitals included in this study lacked computerized medial record systems, and the data were collected manually, using the same method over a long period of time. As data collection and data entry in the registry were performed manually, there was a risk of missing data. To minimize this risk, the staff who completed the forms and data entry were trained at regular intervals. Another strength of this study was that the same form was used for data collection at both hospitals, which enabled comparisons of antibiotic prescribing between the hospitals. A limitation of this study was the absence of medical records and documentation of previous medical history from the included patients. Since there were no medical records or documentation available, no predisposing factors among the patients could be evaluated. Another limitation was that none of the hospitals used microbiological analysis (cultures) consistently. Consequently, most of the diagnoses were based on clinical suspicion. As almost all antibiotic prescribing was empirical, it was not possible to assess whether the antibiotics were rationally prescribed. However, by applying the WHO’s antibiotic categories of access, watch and FDCs of antibiotics, increased in the NTH. In the TH, antibiotic prescribing practices did not change significantly, although prescribing of watch, reserve and FDCs of antibiotics increased between 2008 and 2017. Antibiotic prescribing for pneumonia, peritonitis and cellulitis increased in both hospitals between 2008 and 2017. In the TH, antibiotic prescribing for sepsis decreased but increased in the NTH. The results indicate that antibiotic prescribing practices need to be improved in both hospitals, although the TH generally prescribed more recommended antibiotics and fewer FDCs. Furthermore, the prescribing of recommended antibiotics improved over the study period in the TH. Factors contributing to extensive prescribing of watch antibiotics and FDCs in the NTH could be pressure from pharmaceutical companies and patients, as well as a lack of a local prescribing guidelines. The establishment of antibiotic stewardship programs based on the access, watch and reserve antibiotic categorization, as well as the implementation of locally adapted lists of essential medicines and prescribing guidelines could contribute to improved antibiotic prescribing practices and thus limit the development of antibiotic resistance. Furthermore, the implementation of routine diagnostic methods, such as microbiological analysis, could improve the management of infectious diseases and guide antibiotic therapy decisions for appropriate prescribing of antibiotics. The hospitals included in the present study are typical of those in similar settings in LMICs, and our results are in line with those of previously published studies in this area. The results highlight areas for improvement in antibiotic prescribing practices and same could be anticipated from other similar settings.Over the 10 years period, prescribing of all antibiotic categories, including


A total of 38, 71, and 16 genes were differentially expressed in response to the interaction between heat stress and Met isoforms in the blood, ileum, and liver, respectively. Three-tissue-specific DEGs were functionally enriched for regulation of cholesterol homeostasis and metabolism, glucose metabolism, and vascular patterning. Chicks fed with L-Met had lower immune  and intestinal angiogenic responses , and stable glucose and lipid metabolism  under heat stress conditions. In conclusion, unlike D-Met, L-Met supplementation seems to help maintain physiological homeostasis and enhances cellular defense systems against external stresses like high environmental temperature.The objective of this study was to compare the effects of supplementation with two methionine isoforms, L-methionine (L-Met) or D-methionine (D-Met), on transcriptome expression in broiler chickens under acute heat stress. A total of 240 one-day-old chicks were randomly assigned to one of four treatments in a 2 × 2 factorial arrangement: thermo-neutral vs. acute heat-stress and L-Met vs. D-Met supplementation. On day 14, the heat-stressed group was exposed to 32°C for 5 h, while the others remained at 25°C. Six chicks were randomly selected per treatment and total RNA was isolated from whole blood, ileum, and liver tissues. Two RNA samples from each tissue of each treatment group were randomly selected and pooled in equal amounts. A total of 1.87 billion raw reads obtained from 36 samples (four treatments × three tissues × three composited replicates) were mapped to the reference genome build  and used to identify differentially expressed genes (DEGs) using DESeq2. Functional enrichment of DEGs was tested using DAVID. Comparing the two isoforms of supplemented methionine, two, three, and ten genes were differentially expressed (> 1 or < -1 log Methionine plays an important role in numerous physiological processes   and aspartate aminotransferase [EC: 2.6.1.1]) [.1.5 and et al. [Recently, the average temperature during summer has risen due to climate change. High ambient temperature can cause heat stress in animals, and the deleterious effects of heat stress are more prominent in broilers with higher growth rates . Heat stet al.  examinedet al. . HoweverThe aim of the present study was to compare the effects of L-Met and D-Met supplementation on the expression of the transcriptomes of blood, ileum, and liver in broilers, using RNA-seq. We also investigated whether these effects changed under acute heat stress conditions.This study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the Korean Association For Laboratory Animals (KAFLA). The protocol was also approved by the Committee on the Ethics of Animal Experiments of the Chungnam National University . All sampling was performed after euthanasia, and all efforts were made to minimize suffering.th day, the temperature was increased to 33°C for 2 h, maintained at 33 ± 0.5°C for 3 h, and then returned back to normal temperature (25 ± 1°C). The deep-body temperature of the birds during the acute heat stress period  was measured using a thermistor probe  inserted into the bird’s rectum. Heavy panting, dispersed distribution within the cage, and significantly higher rectal temperature ensured us that the birds were sufficiently heat stressed  were obtained from a commercial hatchery . The experiment was divided into two consecutive periods, with each period (120 birds per period) being of five weeks duration within the same facility under the same experimental protocol. Ten broilers were housed in raised wire-floor pens (0.85 m × 0.55 m × 0.35 m). In the first period, the control group was kept under typical thermo-neutral conditions, with the environmental temperature at 30 ± 1°C from day 1 to 3, gradually decreasing to 25 ± 1°C until 14 d of age, and maintained at 25 ± 1°C throughout the rest of the experimental period. An acute heat-stressed group (HS) was utilized for the second period. The environmental temperatures of the HS group were the same as that of the control group from phase 1 until 14 d of age. On the 14us paper ).3) and were equipped with two nipple drinkers and a metal trough. The experimental diet and drinking water were provided ad libitum throughout the experiment. The average daily feed intake and body weight change of the birds were measured until collection at 14 days of age. There was no significant difference in feed intake and body weight gain between treatments (P > 0.05).Each group of birds was randomly allocated to one of two dietary treatments: with either L-Met or D-Met supplementation. Although DL-Met is commonly used in the field, we used 100% D-Met to compare the physiological consequences of application of its two isoforms. The experimental treatments of this study were as follows: the control group supplemented with L-Met, the control group supplemented with D-Met, the heat-stressed group supplemented with L-Met, and the heat-stressed group supplemented with D-Met based on a 2 × 2 factorial arrangement. Each treatment had six replicates with 10 birds per pen. Since the environmental temperature differed by experimental period, the temperature effect was confounded with the period effect. A basal diet composed mainly of conventional feed ingredients, such as corn, barley, and soybean meal, was formulated to maximize methionine deficiency while meeting the other nutrient requirements for Ross broilers. Either crystalline L-Met or D-Met was supplemented into the basal diet to prepare the experimental diets . Pens haAfter heat treatment, all chicks were treated with the same procedure and raised up to five weeks of age in order to investigate the effects of acute heat stress on growth performance. The detailed experimental procedure can be found in a previous study .One chick per pen for each treatment (six chicks/treatment) was randomly selected after heat stressed chicks were exposed to high temperatures (33°C for 5 h). The chicks were euthanized via cervical dislocation to collect blood, ileum, and liver samples. Blood samples were collected in EDTA tubes from the jugular vein of each chicken. Ileum and liver samples from each chick were collected in 50 ml Falcon tubes. Blood and tissue samples were immediately transported to the laboratory for total RNA isolation.Both tissues were homogenized using a mortar and pestle after being frozen in liquid nitrogen prior to RNA extraction from liver and ileum samples. Total RNA was extracted from the tissues using a RNeasy Mini Kit according to the manufacturer’s instructions . The RNA from whole blood was extracted via QIAamp RNA Blood Mini kit . Total RNA concentration and purity (OD 260/280 ratio) were determined using a Nanodrop 2000 spectrophotometer . The quality of the RNA was also checked using an Agilent Bioanalyzer 2100 . Only RNA samples with OD 260/280 between 1.8 and 2.2 and RNA Integrity Number (RIN) greater than 7 were used for RNA sequencing. The RNA samples were diluted to 50 ng/μl using RNase-free water. Two RNA samples from each treatment group were then randomly selected and pooled in equal amounts. Subsequently, a total of 36 RNA samples (triplicates per three tissues per treatment group) were obtained and stored at -80°C to minimize degradation before RNA sequencing.According to the manufacturer’s manual, the cDNA libraries were constructed using TruSeq RNA Sample Prep Kit . Constructed cDNA libraries were amplified by PCR and purified using 1% formaldehyde-agarose gel. The sequencing libraries were prepared by TruSeq 3000/4000 SBS Kit v3  and were sequenced via HiSeq4000 platform (Illumina) with 101 bp of paired ends.http://www.bioinformatics.babraham.ac.uk/projects/fastqc/) to check the quality of the raw sequence reads. The reads were mapped to the chicken reference genome build, Gallus_gallus-5.0, using TopHat v2.0.4 [First, the RNA-seq reads of each sample were differentiated  according to their indexing adaptors, and then processed with FastQC v0.10.1  [Gene-level mapped reads were counted using HTSeq-count (v.0.6.1p1) based on their alignment to the chicken reference genome build, Gallus_gallus-5.0 (.gtf.gz) . The str.gtf.gz) . For stayijk is the kth observation in the ith combination of tissue and heat stress and jth methionine supplementation, μ is the overall mean, αi is the fixed effect of the ith combination of tissue and heat stress (i = 1 to 6), τj is the fixed effect of the form of supplemented methionine (D-Met or L-Met), ατij is the fixed effect of the interaction between the combination of tissue and heat stress, as well as the form of supplemented methionine, and eijk is the unexplained random error.To see if there are apparent gene expression patterns differed by tissue, heat stress, and the form of supplemented methionine, a statistical analysis was conducted for the interaction between the combination of tissue and heat stress and the form of supplemented methionine. The linear model used for this analysis is as follows:yijk is the kth observation in the ith heat stress treatment, and jth methionine supplementation, μ is the overall mean, ρi is the fixed effect of heat stress (control or heat stress), τj is the fixed effect of the form of supplemented methionine (D-Met or L-Met), and eijk is the unexplained random error.Tissue-specific DEG between the two forms of supplemented methionine after the effect of heat stress was accounted for. The following linear model was tested for each tissue :yijk is the kth observation in the ith heat stress treatment, and jth methionine supplementation, μ is the overall mean, ρi is the fixed effect of heat stress (control or heat stress), τj is the fixed effect of the form of supplemented methionine (D-Met or L-Met), ρτij is the fixed effect of the interaction between heat stress and the form of supplemented methionine, and eijk is the unexplained random error.For each tissue , the interaction between heat stress and the form of supplemented methionine was analyzed, and the following linear model was tested:P-values were adjusted using the Benjamini-Hochberg method (BH) to correct the false positive rate (FDR) test [https://david.ncifcrf.gov/) to explain the biological function of DEGs. DAVID results with an Expression Analysis Systematic Explorer (EASE) score less than 0.05 were defined as significant.To assess the statistical significance of DEGs, generated DR) test . The DEGYF5, SLC6A20, WDR17, DACH2, and LOC417937) to verify the differential expression of DEGs identified by RNA-Seq. These genes were randomly selected from 15 DEGs that showed > 1- or < -1-fold-change differences between the two forms of supplemented methionine  before the pooling process for RNA-seq, according to the manufacturer’s instructions. All primers were designed using the web-based primer design software Primer3 . The criteria of the primer design were set as follows; annealing temperature (Tm) from 58 to 62°C, a primer size of 20–25 mer, and a product size of 100–200 bp. The qPCR amplification was performed on an ABI 7500 Fast Real-Time PCR system  using BioFACT™ 2X Real-Time PCR Master Mix . The PCR cycling conditions were as follows: uracil DNA glycosylase activation at 50°C for 3 min with an initial denaturation step at 95°C for 15 min, followed by 40 denaturation cycles at 95°C for 20 s, annealing at 60°C for 30 s, extension at 72°C for 30 s, and one final extension cycle at 72°C for 5 min. Finally, a melting curve analysis was performed by slowly cooling the reaction mixture from 95°C to 65°C to detect nonspecific amplification products. The housekeeping gene ACTB (β-actin) was used as the internal control  analysis for five genes  using the Illumina HiSeq 4000 sequencing platform  Tables. A total of 258 genes were differentially expressed in response to the interaction among tissue, heat stress, and the form of supplemented methionine (FDR < 0.05). Hierarchical clustering based on their expression clearly showed distinct gene expression patterns among tissues and between treatments . DEG exp2 fold change difference between the two dietary treatments in whole blood, ileum, and liver, respectively  selected from the DEGs identified by RNA-seq showed a good agreement between the expression patterns of RNA-seq and real-time qRT-PCR results .A total of 3, 4, and 22 genes were differentially expressed for the two supplemented methionine isoforms in whole blood, ileum, and liver, respectively (FDR < 0.05). Among them, two, three, and ten genes showed greater than 1 or less than -1 logectively . The rea results . The logATP13A5, related to the transport of inorganic cations, and uncharacterized LOC107051457 gene were higher in L-Met than in D-Met. On the contrary, LOC107057378, which performs a role in anti-microbial and anti-tumor defenses, was up-regulated in the D-Met treatment when compared with the L-Met treatment, which may indicate that anti-inflammatory responses were up-regulated in the chicks fed D-Met.In ileum, the expression of LOC417937 (regulating vitamin C transport), GRIN3B (regulating glutamate-gated ion channels), LOC100859807 (immune response), LOC107054990 (uncharacterized gene), LOC107051423 (regulating actin cytoskeleton), ZNF185L (regulating actin cytoskeleton and cellular differentiation and/or proliferation), SLC6A20 , and TLDC2 (oxidative stress resistance). DACH2 related to myogenesis, and WDR17 related to autosomal recessive retinitis, were the two genes that were up-regulated in the L-Met treatment when compared with the D-Met treatment.Expression of eight out of the ten DEG genes in the liver was downregulated in the L-Met treatment when compared with the D-Met treatment, while the expression of the remaining two genes was upregulated. The eight genes down-regulated in L-Met were: Analysis for each tissue indicated that 38, 71, and 16 genes were differentially expressed (FDR < 0.05) in response to the interaction between heat stress and the forms of supplemented methionine (L-Met vs. D-Met) in whole blood, ileum, and liver, respectively  Tables. IL4I1 (Interleukin 4 Induced 1) and SERPIN1 (serpin family I member 1) in whole blood of broiler chicks fed with D-Met, which are related to immune response and neuroprotection (PCK1 (phosphoenolpyruvate carboxykinase 1) decreased, which is a main control point for the regulation of gluconeogenesis , related to the endocytosis of low-density lipoprotein, increased in the D-Met group under acute heat stress conditions, but not in the L-Met group (FLT1 (fms related tyrosine kinase 1) and FGD , related to angiogenesis and vasculogenesis, were relatively low in the D-Met group under normal temperature when compared with the L-Met supplemented group. The expression of these genes, however, dramatically increased in the D-Met group when exposed to a high ambient temperature , and plays an important role in the regulation of electrolyte homeostasis, cell signaling, survival, and proliferation by inhibiting the activity of the thiazide-sensitive Na-Cl cotransporter (NCC), epithelial Na+ channel (ENaC), and renal outer medullary K+ channel (ROMK). This gene increases paracellular chloride permeability [YF5 gene is a major histocompatibility complex (MHC) class I gene conserved in many species including human, mouse, and zebrafish [YF5 increases with viral infections.In the blood, the expression of eability  and causeability . The YF5ebrafish . The MHCebrafish , 24, whoIn this study, results from the multi-tissue transcriptomic analysis showed that immune response, lipid  metabolism and transport, and glucose metabolism were altered by the interaction between heat stress and the isoform of supplemented methionine. Compared with the D-Met supplemented group, the L-Met supplemented group appeared to have less cellular and metabolic responses to heat stress.IL4I1 and SERPINI1) indicated that acute heat stress enhanced cellular immune responses in the D-Met supplemented group, but not in the L-Met group. When chicks were exposed to acute heat stress, the expression of IL4I1 (Interleukin 4 Induced 1), which encodes L-amino acid oxidase and catalyzes the oxidation of L-amino acids, was significantly increased in the D-Met supplemented group, but not in the L-Met group. Zhang et al. [IL4I1 enhanced the innate immune response and serum IgY concentration in chicken. The expression of IL4I1 is induced by interleukin 4 (IL-4), which also up-regulates heat shock genes and stimulates the cellular responses under heat stress [IL4I1 in the L-Met supplemented group indicates that the cellular response to heat stress, mediated by IL-4, was not induced in this group. Reduced immune response to heat stress in the L-Met supplemented group was also supported by the lowered expression of SERPINI1 (serpin family I member 1) in the L-Met supplemented group after exposure to heat stress. The SERPINI1 gene encodes neuroserpin, which has an antioxidant defense mechanism and plays an important role in protecting neurons against oxidative stress [SERPINI1 in the D-Met supplemented group implied that oxidative stress was more profound when compared with the L-Met supplemented group.The expression patterns of some DEGs  and PCKm  was significantly increased in the broiler group exposed to heat stress.Several DEGs suggest that, under acute heat stress conditions, lipid and glucose metabolism were altered in the D-Met group, but not in the L-Met group. Oxidative stress associated with high ambient temperature is known to markedly increase the concentration of plasma glucose and cholesterol in poultry , 31. It ynthesis , 35. In a et al.  reportedLDLR (low-density lipoprotein receptor) was up-regulated in the D-Met supplemented group under heat stress conditions. The LDLR uptake circulates LDL into the liver and regulates intracellular cholesterol levels [GREM2 (Gremlin 2). Wu et al. [GREM2 was significantly down-regulated by a high concentration of blood cholesterol. They reported that GREM2 inhibits adipogenesis through Wnt/β-catenin signaling. Overall, in our study the DEG expression patterns suggest that broiler chicks supplemented with D-Met had an activated cellular response to reduce circular cholesterol and glucose levels when exposed to acute heat stress conditions.In addition, several key hepatic reactions related to hypercholesterolemia were up-regulated in the D-Met supplemented group when they were exposed to acute heat stress. Serum concentrations of total cholesterol and LDL-cholesterol were generally increased in broilers that undergo heat stress . In the l levels . The actu et al.  showed tFLT1 (fms related tyrosine kinase 1) and FGD5  were lower in the D-Met group under normal conditions but were dramatically elevated under heat stress conditions. The FLT1 gene is mainly expressed in vascular epithelial cells and plays an important role in angiogenesis and vasculogenesis [FGD5 gene plays a role in the regulation of the proangiogenic action in vascular endothelial cells [FLT1 under heat stress and hypoxic conditions [Compared with the L-Met group, intestinal angiogenic responses to heat stress appeared to be induced in the D-Met supplemented group. The expression of ogenesis . The FGDal cells . Heat stal cells , and it al cells . Similarnditions , 45.IGF-1, GHR, CTSL2, and atrogin-1) that were reported to reduce protein degradation induced by heat stress [Consequently, the current multi-tissue transcriptomic analysis showed that broiler chicks supplemented with L-Met were less stressed than D-Met when acutely exposed to high temperature. Unlike D-Met, L-Met supplementation appears to help maintain physiological homeostasis and enhance the defense system against external stresses . The discrepancy between L-Met and D-Met could be due to the higher bioavailability of L-Met and increasing doses of D-Met can potentially have similar effects. The underlying mechanism by which the L-Met supplementation reduces physiological stress produced by high temperature is still unknown. It can be speculated that the antioxidant activity of methionine, which reduces ROS-induced oxidative stress , was enht stress  were notS1 Fig(TIF)Click here for additional data file.S2 FigThe genes were differentially expressed in response to the interaction among tissue, heat stress, and the form of supplemented methionine. Abbreviations: BLD, whole blood; ILM, ileum; LVR, liver; CON, control group; HS, acute heat stressed group; L, L-Met supplementation; D, D-Met supplementation.(TIF)Click here for additional data file.S1 Table(XLSX)Click here for additional data file.S2 Table(XLSX)Click here for additional data file.S3 Table(XLSX)Click here for additional data file.S4 Table(XLSX)Click here for additional data file.S5 Table(XLSX)Click here for additional data file.S6 Table(XLSX)Click here for additional data file.S7 Table(XLSX)Click here for additional data file.S8 Table(XLSX)Click here for additional data file.


Scientific work is usually quite time-intensive and frequently replete with frustrations. In the fields of mathematics and philosophy, for example, a single question might occupy one’s attention for an entire lifetime, without necessarily ever reaching a conclusion. Scientific work in the field of medicine evolves under essentially different conditions. Hippokrates therefore used the Greek term “iatrike techne” (ιατρική τέχνη) —or in Latin, “ars medica”—instead of medical science.In medicine, we want and in fact have to reach conclusions quickly, partly because this is what we demand of ourselves to fulfill our criteria for scientific work, but also partly because we are searching for practical solutions which just cannot be delayed.This is frequently the problem with translating basic science to clinical science. Basic scientists can very well focus preferably on concrete issues and demand concrete solutions, while clinical scientists must always live and work with limited knowledge and many uncertain factors for the simple reason that their studies cannot be conducted under laboratory conditions. We also must remember that we are involved with numerous premises and hypotheses which cannot be substantiated in the intermediate term, although they still determine our day-to-day work.In order to be accepted, scientific hypotheses must be testable empirically. They are then either confirmed or refuted. In clinical settings, however, there is a considerable tendency towards generalizing, and from empirical and/or clinical findings, conclusions are drawn and hypotheses are advanced without testing for their validity. When results contradict the favored hypotheses , this very often leads to these results then being fully ignored. Our work is not consistently inductive or deductive. For example, we publish case reports and generalize relatively uncritically our observations and draw conclusions for the disease as a whole (induction), or we work deductively by drawing conclusions from the general picture of a disease  regarding the concrete case  . This siIn a number of fields in clinical medicine, hypotheses build upon other hypotheses. However, even in the event that one hypothesis is disproven or is seen as no longer compelling and conclusive, the other related popular clinical hypotheses are not automatically rejected but rather continue to be accepted. For example, the Braak hypotheses are basically only reconcilable to a limited degree with other diagnostic and therapeutic routines. This all results in a rather complex situation which is interpreted by different workers in very different ways.In the clinical sciences, we tend to view disease patterns much in the way of a puzzle: the more information we have , the better we assume that we understand the entire disease. Vice versa, however, we also strongly want to form some concept of the bigger picture (even when our findings are still only insufficient) and might even be tempted to adapt our present findings accordingly: what does not match is made to match. Alternatively, at least when new findings do not fit our preliminary concept exactly, they are frequently ignored .With Parkinson’s syndrome, these aspects are particularly relevant in as much as the disorder has to be viewed multi-dimensionally. We not have only one single unified entity but rather many clusters which overlap considerably, congruent in the long run but still unique. Every new finding can essentially alter the basic concept.It is a matter of course that every scientist considers their own publication work as highly important, while not forgetting to place it in the appropriate context with that of others. This is the theme of translational science, which calls for people who have schooling in both basic science and clinical medicine. They necessarily have to occupy themselves with the disease on both the clinical and the scientific level, but because the flood of information is constantly expanding, this is becoming less and less realizable: we just cannot know all the most recent studies. We have to satisfy ourselves with only a selection of the material (selective perception). The modern day reviewing process automatically means that certain opinions are better reinforced while others are relegated to the periphery.When findings match the present day teachings and the corresponding publications are cited, they are more eagerly accepted than when the results contradict the mainstream. As a case in point, the literature on the role of the intestines in Parkinson’s syndrome was controversial in the 1990s and was accordingly viewed critically. In contrast, today, we face a large number of publications which directly postulate just such a role of the intestines and the microbiome in the pathogenesis of Parkinson’s, although, strictly speaking, the exact data do not (yet) substantiate this assumption.These considerations form the basis for our publication “Molecular and Cellular Mechanisms of Parkinson’s Disease”. Workers from the field of the basic sciences and clinicians must cooperate; they must pool their findings and knowledge so as to develop a joint view. In this pursuit, there must be a willingness to accept the limits of everyone’s own research and to recognize one’s own errors. Too often, hypotheses that are simply inaccurate are perpetuated and become perennial sources of further research. We must be prepared to return to our original situation when a disease is first being described and then validate our hypotheses with our present day knowledge. In the present Special Issue, we wish to help resolve this problem by working together, pooling our efforts, and translating them into the biomedical sciences.