In total, sixteen samples were manufactured—four samples per zirconia material. Additionally, the morphology, grain size area distribution, and elemental composition were analyzed in parallelepiped samples made from the selected types of zirconia in three different areas, noted as the upper, middle, and lower areas. The scanning electron microscope (SEM) analysis highlighted that the grain size area varies with respect to the researched area and the type of material. Defects such as microcracks and pores were also noted to a smaller extent. In terms of grain size area, it was observed that most of the particles in all samples were under 0.5 μm2, while the chemical composition of the investigated materials did not vary significantly. The results obtained after performing the bending tests showed that a zirconia material with fewer structural defects and an increased percentage of grain size area under 0.5 µm2, ranging from ~44% in the upper area to ~74% in the lower area, exhibited enhanced mechanical behavior. Overall, the resulting values of all investigated parameters confirm that the tested materials are suitable for clinical use.The fabrication of fixed dental prostheses using aesthetic materials has become routine in today’s dentistry. In the present study, three-unit full zirconia fixed prosthetic restorations obtained by computer-aided design/computer-aided manufacturing (CAD/CAM) technology were tested by bending trials. The prostheses were intended to replace the first mandibular left molar and were manufactured from four different types of zirconia bioceramics (KatanaTM Zirconia HTML and KatanaTM Zirconia STML/Kuraray Noritake Dental Inc.; NOVAZir One’s public image is becoming an important facet of contemporary society. Satisfying aesthetic needs complements medical treatment and, as a consequence, has become common practice in prosthetic dentistry ,2,3,4, aConcerns regarding the use of aesthetic restorations in the posterior area of the dental arches have been related to the mechanical and optical properties of the available dental materials . VeneeriMonolithic zirconia crowns in the posterior area showed optimal marginal adaptation, cervical margin integrity, and color match. Very promising clinical results were also reported regarding the influence on periodontal tissues and the wear of antagonist teeth .Analyzing the fracture resistance of 136944 zirconia restorations  in both anterior and posterior areas, Sulaiman et al.  observedThe main motivations for using the newly developed zirconia-based materials have been to improve the appearance of restorations, maintain their material strength so that they should withstand mechanical stress, and preserve their internal and marginal fit, chemical stability, and biocompatibility in the complex oral environment ,23,24,25The main objectives of the present study were to investigate the morphology, chemical composition, and fracture resistance of certain newly developed multilayered zirconia materials with augmented optical and mechanical properties. These materials were examined by means of scanning electron microscopy and energy-dispersive spectroscopy. Three-unit fixed dental prosthesis samples were afterwards manufactured from these materials and subjected to bending tests. The null hypothesis was stated as follows: the new zirconia-based ceramic materials with progressively increased translucency exhibit results comparable with conventional zirconia specimens with constant flexural strength.In the current study, four types of zirconia-based materials were investigated. TM Zirconia HTML (high-translucency multilayered) and STML (super-translucent multilayered) are produced by Kuraray Noritake Dental Inc. , providing, according to the manufacturer, a constant flexural strength of approximately 1100 MPa and 750 MPa, respectively. NOVAZir® Fusion float® ml  is a multilayered zirconia disc with a flexural strength ranging from 800 MPa in the occlusal area up to 1100 MPa in the cervical area. 3D PRO Zirconia from Bloomden Bioceramics  is also a multilayered disc, with a flexural strength varying from 650 to 1100 MPa.KATANAThe morphology and elemental composition were examined by SEM equipped with an energy-dispersive spectrometer (EDS) . These characteristics were studied on three different areas of the parallelepiped samples obtained from the zirconia discs by using CAD/CAM technology, to observe the grain modifications. Three-unit zirconia dental prostheses corresponding to the replacement of the first mandibular left molar were manufactured by computer-aided design/computer-aided manufacturing (CAD/CAM) technology and then subjected to bending tests. A Co-Cr dental alloy  abutment model, featuring the absence of the first mandibular left molar, was first obtained by CAD/CAM technology and, based on it, the zirconia samples were designed. Using Trios Design Studio software (3Shape), an STL file containing the three-unit prosthesis design was generated and imported into the CAM software. To avoid any force deflection that may be generated by the cuspal inclines, the anatomic occlusal surface was leveled into a horizontal plateau, using Meshmixer . This design can mimic the flatter occlusal surfaces, with reduced cusp inclinations, that are specific to prosthetic restorations recommended for clinical cases of old partial edentulism, for patients with bruxism or with a pattern of horizontal masticatory movements.In the nesting process, the designed prosthesis models were positioned in the entire-disc thickness, addressing all material layers .The experimental samples were obtained with a CORITEC 350i  milling machine and then sintered according to each manufacturer technical data sheet in an MIHM-VOGT HT sintering furnace .TM Zirconia HTML and KatanaTM Zirconia STML/Kuraray Noritake Dental Inc; NOVAZir® Fusion float® ml/NOVADENT/Dentaltechnik; and 3D PRO Zirconia/Bloomden Bioceramics)  . RespectThe bending resistance of the zirconia specimens was studied by applying a three-point bending test using an Instron 8872 Universal Testing Machine  equipped with a load cell of 25 kN. The testing speed was set to 1mm/min. A custom-made support was manufactured, and the load was applied on the pontic of the zirconia dental prostheses, using a plate for the purpose of reproducing the occlusal force .The force was applied in the middle of the pontic and the test was carried out until a fracture occurred. Images and slow-motion videos were recorded for each tested sample.The SEM images of the investigated specimens at different magnifications are presented in -The K-H specimens present both large and small grains, randomly distributed;-The B specimens present larger grains in the upper region, the grain size decreasing gradually to the lower region;-The N specimens have a multilayered structure regardless of the examined area, which consists of one layer with smaller grains, followed by a layer with larger ones;-Compared to the other investigated materials, the K-S specimens present the largest grains.All samples present both large and small grains, differently distributed throughout the material. The main findings with respect to the grain dimension are presented below:2) was measured with Image J software by using the SEM images, and the results are presented in 2, in all three of the different regions of each sample, as indicated in 2.Because the morphology of zirconia consists of grains with irregular shapes, the grain size area . This layered distribution was observed in all three investigated sections of sample N.2, ranging from ~44% in the upper region  to a maximum of ~74% in the bottom region , while the percentage of larger particles (whose area is higher than 0.5 µm2) decreases when passing from the upper to the lower section. When passing to the lower area, most of the particles were below 3 µm2.It was noticed that the B and K-S zirconia samples exhibited a dissimilar particle distribution compared to the other two specimens. The B zirconia samples presented different percentages of particles whose grain size is below 0.5 µm2 (a min. of ~56% in the middle area and a max. of ~60% in the upper area).On the other hand, regardless of the investigated area, the K-S zirconia samples presented the lowest percentage of particles whose area was below 0.5 µmOverall, the distribution of the grain size follows the same trend when passing from the upper to the lower area for all four types of zirconia included in our study. Moreover, it can be noted that by advancing from the upper region to the bottom one, the percentage of particles had the same trend .The elemental distribution and chemical composition obtained on the basis of the EDS analysis performed on three different  areas of zirconia parallelepiped samples are indicated in The research revealed that elements are uniformly distributed in all investigated materials . It was Each zirconia sample corresponding to the three-unit dental prostheses was placed in the custom-made support and the steel plate was positioned on the central area of its surface, as shown in The bending test was carried out by applying a 1 mm/min crosshead speed until fracture occurred. The load–displacement curves are presented in After the bending tests, it was observed that all zirconia samples exhibited brittle failure in which the fragments perfectly fitted each other along the fracture line. Immediately after the initial fracture, total failure has occurred. In As a general observation, the zirconia materials act differently under the same experimental conditions. Thus, the highest force at failure values were recorded for the B zirconia prostheses (2.00 ± 0.14 kN), followed by K-H and N samples, while the lowest values were obtained for the K-S specimens . With respect to the mechanical tests performed, it can be assumed that the bending strength of the three-unit zirconia dental prostheses is influenced by the following critical factors: the size, shape, and distribution of particles in addition to the presence of material defects. The chemical composition of the tested materials does not appear to influence their mechanical properties as there are no significant variations in the concentration of elements, regardless of the investigated area or material.-2) and larger particles (between 1 and 5 µm2), while the lower areas are comprised of a very large number of grains whose maximum size is 2 µm2;The best results were obtained for sample B as its investigated upper and middle areas consist of smaller  benefits from transformation toughening and has demonstrated excellent mechanical properties, such as high strength (prevention of crack initiation) and toughness (damage tolerance upon the occurrence of cracks) . HoweverThe above-mentioned positive aspects related to the mechanical behavior of monolithic zirconia rely on the specific characteristics of the material, which has a polymorphic crystalline structure that varies with temperature. In contrast to other ceramic materials, zirconia can pass from one crystalline phase to another during the thermal process . The cry2O3), magnesia (MgO), ceria (CeO2), or calcia (CaO) are added, stabilized tetragonal zirconia polycrystals are obtained [The transformation toughening, which is specific to zirconia, has proved useful, especially when the initial cracks occur. The stress contraction produced by the crack dispersion in the matrix represents a triggering factor, causing the particles that were uniformly dispersed during the T phase to pass into the M phase (martensitic transformation) . This phobtained ,39,40. Tobtained . However2 and Al2O3, respectively [High flexural strength was reported for glass-infiltrated zirconia-toughened alumina (ZTA), characterized by a microstructure with large alumina grains , small zirconia grains (<1 µm in diameter), and few faceted zirconia grains (2 µm); trans-granular crack patterns and intra-granular patterns were observed for ZrOectively . The advectively .As cited in the dental literature , 3Y-TZP 2, which corresponds to the manufacturer’s specifications regarding material strength for all samples. Furthermore, a small grain size has a positive effect on the polish potential of the final prosthesis [Other studies ,42,43 poosthesis .Along with other studies which highlighted the fact that the strength of three-unit zirconia bridges is influenced by the design and connector geometry , the aimAll the investigated samples presented defects, and the stress intensity factor was affected by the defects´ shape, depth, and width. Microcracks and defects that inherently grow during the thermal and mechanical processes can significantly influence the measurement of fracture resistance ,48,49. AConsidering the recommendation of these materials for fabricating dental prostheses, special attention must be paid to the masticatory forces, which are the result of a complex interaction between the masticatory muscles, dental arches, maxillary structures, and specific masticatory movements . The evaAs already mentioned in the present study, the intraoral use of zirconia as a restorative material is also associated with, apart from possible fractures, complications such as chemical aging and the wear of antagonist teeth. Chemical aging is also known as low temperature degradation; water can destabilize the meta-stable tetragonal zirconia grains , so that the volume increase associated with phase change can cause local stresses and microcracks near the surface . This, i2), which will significantly improve the aesthetic appearance of the material, but will also produce modifications of the Young modulus, with a direct influence on the tensile strength [2) powder containing nanoparticles; however, due to the complex processing, it is difficult to obtain a homogeneous powder.Several generations of zirconia have been developed until now ,23,56, wZirconia is nowadays considered to be one of the most used bioceramic material for single- and multi-unit fixed dental restorations or for abutments and infrastructures of implant-supported prostheses.In the present study, three-unit zirconia fixed dental prostheses manufactured by CAD/CAM technology were subjected to bending strength testing. Four types of zirconia materials were purchased from different suppliers. Our findings highlighted the following aspects: according to SEM investigations, the tested materials have different particle sizes, and defects are visible in some of them; the EDS analysis showed the presence of all specific elements in the tested zirconia samples , and no major differences in regard to chemical composition were observed among the samples; the bending tests indicated that the highest forces at the failure values were registered for the B zirconia samples, followed by K-H and N samples, while the lowest values were obtained for the K-S specimens; and bending strength proved to be in correlation with the particle size and distribution, but also with the presence of certain defects in the zirconia material. Nevertheless, all investigated materials have exhibited higher fracture toughness values than the ones clinically accepted.Within the limitations of our study, we were able to confirm the hypothesis that the new zirconia-based materials with progressively increased translucency offer results comparable to those of materials with constant flexural strength when subjected to a three-point bending test. Nevertheless, additional scientific studies are required to confirm the results we have obtained.In perspective, other aspects such as phase identification and distribution within the structure, usage of different sintering temperature, or other key factors that can influence the behavior of zirconia need to be thoroughly analyzed and corroborated by finite element simulations, with the aim of gathering additional scientific information and a clearer insight on these issues.


Stiffness, the resistance to deformation due to force, has been used to model the way in which the lower body responds to landing during cyclic motions such as running and jumping. Vertical, leg, and joint stiffness provide a useful model for investigating the store and release of potential elastic energy via the musculotendinous unit in the stretch-shortening cycle and may provide insight into sport performance. This review is aimed at assessing the effect of vertical, leg, and joint stiffness on running performance as such an investigation may provide greater insight into performance during this common form of locomotion. PubMed and SPORTDiscus databases were searched resulting in 92 publications on vertical, leg, and joint stiffness and running performance. Vertical stiffness increases with running velocity and stride frequency. Higher vertical stiffness differentiated elite runners from lower-performing athletes and was also associated with a lower oxygen cost. In contrast, leg stiffness remains relatively constant with increasing velocity and is not strongly related to the aerobic demand and fatigue. Hip and knee joint stiffness are reported to increase with velocity, and a lower ankle and higher knee joint stiffness are linked to a lower oxygen cost of running; however, no relationship with performance has yet been investigated. Theoretically, there is a desired “leg-spring” stiffness value at which potential elastic energy return is maximised and this is specific to the individual. It appears that higher “leg-spring” stiffness is desirable for running performance; however, more research is needed to investigate the relationship of all three lower limb joint springs as the hip joint is often neglected. There is still no clear answer how training could affect mechanical stiffness during running. Studies including muscle activation and separate analyses of local tissues (tendons) are needed to investigate mechanical stiffness as a global variable associated with sports performance. F) and the deformation (Δl) of the body. Therefore, as a part of Hooke's law, stiffness (K) was defined as a ratio of the amount of deforming force (or force change) to the unit of deformation  [Stiffness is a quantitative measure of the elastic properties of the body and determines the ability to accumulate potential elastic energy. The concept of stiffness was developed in classical mechanics to describe the behaviour of elastic deformable bodies under application of external forces. In the seventeenth century, the British physicist Robert Hook stated a proportional relationship between the magnitude of the deforming force (motions) –3.Elastic deformable bodies have the ability to recover the previous shape and volume  after mechanical forces that cause deformation are removed. These deformations are fully reversible. Due to the influence of external deforming forces, the elastic bodies accumulate potential elastic energy, which they release back to the system when returning to the original length. The work performed by the deforming forces equals the value of the potential elastic energy accumulated in the spring compliance elements (assuming there are no energy losses due to friction and resistance forces) , 3.The ability to absorb and return potential elastic energy is also observed in the musculotendinous groups in the human body. The potential elastic energy stored by the passive structures (tendon and aponeurosis) during contractile cycle of a muscle, e.g., during lengthening of the entire muscle-tendon unit, can increase the energy supplied by the compliant tissues during the proceeding shortening phase. Consequently, the substantial capacity of the tendon and aponeurosis to store elastic strain energy can enhance the total mechanical energy produced by the muscle-tendon unit during the concentric phase of muscle work or reduce muscle fibre work and metabolic energy expenditure. Potential elastic energy stored in muscle-tendon units reduces the metabolic energy spent by muscles responsible for movement in specific joints and is associated with the change in the kinetic energy of the body being moved –7. ThereHowever, the strict concept of stiffness has been introduced for relatively simple passive bodies . A human muscle (as a whole) does not behave like a passive body with linear force-deformation characteristics . The musdF/dl might contain components originating from inertial forces and damping. Therefore, the variable measured in the above case is not stiffness viewed in strict mechanical terms due to the substantial contribution of other factors that affect the F(Δl) relationship, especially during transient states. In locomotion analyses when the body is in motion, certain “varieties” of stiffness are used [Stiffness should be understood as the resistance does not depend on time, velocity, or acceleration, but only on the displacement . The proper measurements of stiffness are performed during steady-state body deformation (from one equilibrium state to another equilibrium state). If stiffness measurements are not performed during steady-state body deformation but during transient states, the substantial value of are used , 3.With respect to living bodies, the mechanical stiffness can be divided into quasi-stiffness and joint stiffness. Latash and Zatsiorsky  defined The relationships between mechanical stiffness  and movement performance are areas of interest to the sport and research communities. Several authors have already tried to organise an understanding of stiffness in their review articles , 21–30. Some reports refer to changes in stiffness under the influence of sports training . However, they take into account the stiffness of local structures  –46; the It would be expected that a stiffer “leg-spring” may increase athletic performance by enhanced utilisation of potential elastic energy. Therefore, the aim of this overview is to examine the relationships between mechanical stiffness  and running performance, both in cross-sectional and training studies. Such a review is important as many studies assessing stiffness in humans have focused on jumping or hopping motions that are not commonly performed in sporting events, with the majority of the studies being cross-sectional in design. This review may provide additional insight regarding how different stiffness values obtained from running tasks may be representative of common sporting locomotor activities and how training-related changes in stiffness characteristics may underpin improvements in running performance.Papers written in English onlyStudies with human samplesNo duplicates No publication time restrictionA search of the PubMed and SPORTDiscus (EBSCO) bibliographic electronic databases was conducted in October 2020. The search terms used included  AND (“stiffness”) AND (“run∗” OR “sprint∗” OR “jog∗”) AND (“sport”). Review and original empirical research articles and other related literature were selected based on the title and abstract. Additionally, Google Scholar, ResearchGate, and the reference lists of articles found were also checked to ensure no relevant studies were omitted during searching process. The following criteria were considered:Only studies which had measures of mechanical  stiffness during running performance were included in further analysis. Studies describing other human movements , studies analysing the type of footwear, studies which failed to determine stiffness during the running performance , and modelling-based studies or those concerning different types of stiffness than mechanical have been omitted. After a detailed review of the full texts, 92 meet all the criteria  with a pKleg) and vertical stiffness (Kvert) are expressed by the following equations:F is the deforming force (the causes of the change in deformation), ΔL denotes the change in “leg-spring” length (deformation), and Δy is the displacement of COM (deformation). However, if the relationship between the deforming force and the deformation is nonlinear or deformation is plastic, the derivative (d) from Equations  and can be considered in accordance with the assumptions of spring-mass model (in which the lower limbs perform the role of “springs” responsible for the COM movement). Leg and vertical stiffness are commonly used to describe the mechanical properties of a “leg-spring” representing the lower limbs during running task .  Figurequations  or 3) s sKleg) aF equals the value of the potential elastic energy accumulated in the spring compliance elements. Potential elastic energy is proportional to the square of deformation and can be given by the following equation:Epe is the potential elastic energy, K denotes the stiffness , and Δl is the deformation .The work performed by the deforming forces If stride frequency is relatively constant or the acceleration of the runners COM is relatively low (relatively constant movement velocity), then quasi-stiffness  does not significantly change during running –57. TherVertical stiffness increases with running velocity and stride frequency , 58–68 a2 consumption. Heise and Martin [An important factor that affects vertical stiffness and stride frequency is fatigue. Dalleau et al.  reportedd Martin  concluded Martin  and 5 m/d Martin ). Dutto d Martin  observedd Martin . Hobara d Martin  noted thd Martin  reportedd Martin . Girard d Martin  showed td Martin . Other sd Martin , three sd Martin , six 20 d Martin , twelve d Martin , six 30 d Martin , and durd Martin . TherefoIt is also possible to change (decrease) leg and vertical stiffness by running with different (increased) knee flexion . This type of running technique lowers ground reaction forces and reduces flight time, but requires increased metabolic power (oxygen consumption) –85. The In contrast to vertical stiffness, leg stiffness (with increasing running velocity) remains relatively constant or changes (increase) to a smaller extent during running –68, 81. However, it is possible to change leg stiffness value more than twofold by increasing stride frequency at a given running velocity . Therefo2max [In contrast to vertical stiffness, leg stiffness is not strongly related to the aerobic demand of running and fatigue , 91–98. 2max –102 and 2max  during w2max  reported2max . Li et a2max  reported2max  noted th2max  found th2max  during R2max . Other s2max , 105–107At relatively low running velocity, runners predominantly hit the ground with the heel (heel strike), whereas at higher running velocity (sprinting), the foot strike is usually performed with the forefoot , 108. ReLeg stiffness is also likely to influence the ability to effectively execute change of direction tasks. Greater leg stiffness allows to less loss of velocity when changing direction . An inabThe difference in behaviour between vertical stiffness and leg stiffness during running tasks is potentially due to the fact that leg stiffness is mainly determined through the mechanical properties and activation of lower limb musculotendinous system with only small “leg-spring” stiffness variations depending on velocity. Vertical stiffness is not only reliant on the properties and activation of the lower limb but also on the whole body . MoreoveQuasi-stiffness is a concept that considers the limb (leg stiffness) or body  as a whole system rather than only the musculotendinous system. Therefore, quasi-stiffness also depends on the stiffness of other tissues, such as ligaments, blood vessels, and bones. The elastic properties and the ability to accumulate potential elastic energy are different for each of these tissues . HoweverKjoint) is expressed by the following equation:M denotes the deforming torque and Δα is the angle of deformation. However, if the relationship between the deforming torque and the angle of deformation is nonlinear or deformation is plastic, the derivative (d) from Equation  offers a different view of “leg-spring” stiffness than the quasi-stiffness. Knee joint stiffness increased with running velocity , 116. ArIn turn, ankle joint stiffness (with increasing running velocity) remains relatively constant or changes (increase) to a smaller extent compared to knee joint stiffness , 118. StKleg−spring is the “leg-spring” stiffness, Kankle denotes the ankle joint stiffness, Kknee is the knee joint stiffness, and Khip is hip joint stiffness.Larger peak moment and mechanical power values at the ankle and knee joints are observed with increasing running velocity . RunningTherefore, depending on the running velocity, theoretically, knee joint stiffness or ankle joint stiffness will have the most influence of overall “leg-spring” stiffness. Ankle joint spring should be more compliant than knee joint spring during substantial running velocity (sprinting). Günther and Blickhan  concludeLower ankle joint stiffness and greater knee joint stiffness were associated with lower oxygen consumption during constant velocity running. More economical runners are characterised also with short ground contact times and greater stride frequencies . Weir etThe assessment of training effects in runners seems to be the most correct when it is carried out with the use of running tests. Therefore, the possible changes in mechanical stiffness can then be determined based on a measurement during running. In contrast, Rumpf et al.  observedWhile McMahon et al.  and BrazThe total mechanical energy involved in human body movement is the sum of kinetic and potential energy. With each running stride, the kinetic energy change of horizontal motion (related to the braking action of the ground) and the gravitational potential energy change due to the  displacements of the runners COM. Potential elastic energy is associated with the change in the kinetic energy of the body being moved. Due to braking and lowering of the runners COM in the initial part (absorption) of the ground contact phase during running, the decrease in the kinetic energy and gravitational potential energy is partially stored in the form of potential elastic energy by the stretched musculotendinous groups. The ability of the musculotendinous groups to store and return potential elastic energy increases the mechanical energy supplied by active contracting muscles used in the take-off phase. Consequently, the total mechanical energy supplied by the entire muscle-tendon unit during the propulsion phase can obtain greater values and/or less work needs to be performed by the muscles' contractile elements , 6. A ceThe total “leg-spring” involves many skeletal muscles and tendons and other passive structures. These tissues can be stretched and recoil and consequently accumulate potential elastic energy during these actions . During For a given human body modelled as a spring-mass system , some particular value of the “leg-spring” stiffness may hypothetically be the most beneficial for movement performance. Greater or lower “leg-spring” stiffness compared to desired values can cause the lower limbs to partially lose elastic capacity, which will have a negative effect on the accumulation and utilization of elastic energy. If the “leg-spring” is too stiff, the body may take-off too soon reducing the capacity to improve flight time through addition of muscular force. If the “leg-spring” is too compliant, the body may rise too late with considerable energy lost through relaxation of the elastic tissue, thereby reducing the advantage for the musculotendinous system during the SSC .“Leg-spring” stiffness is expected to be greater in athletes than nonathletes during running tasks. With similar changes in the length of the “leg-spring”, athletes release greater force than nonathletes. Therefore, increases in “leg-spring” stiffness make it theoretically possible for runners to absorb greater loads, as a higher level of deforming force (torque) is required to perform joint movement. This phenomenon may be important in training, as it allows for working with higher loads. However, based on the analysis of vertical jumps, it seems that the desired “leg-spring” stiffness value is relatively small in relation to the “maximum” .Greater accumulation of potential elastic energy may occur by increasing stiffness and/or deformation. However, according to Equation , increasBecause athletes are able to generate a greater ground reaction force than nonathletes, their maximum “leg-spring” stiffness is greater. Therefore, a relatively low “leg-spring” stiffness will be greater for an athlete than for a nonathlete. The greater value of “leg-spring” stiffness in athletes (in comparison to nonathletes) will be (on the condition that the desired range of motion in the lower limb joints is obtained) an additional factor that increases the accumulated potential elastic energy and, consequently, performance. Therefore, the desired “leg-spring” stiffness value can be an individual variable property .The speculations concerning a desirable value “leg-spring” stiffness that is the most advantageous for the accumulation of potential elastic energy and most favours reaching maximal sport performance have already been addressed in many previous studies , 31–35. The studies included in this review utilised several computational methods to estimate mechanical stiffness, with such approaches not always necessarily yielding the same values , 138–143Another important factor that seems necessary to take into account in stiffness estimation is body mass. A positive relationship between stiffness and body mass can result from maintaining the natural vibration frequency of the human body, which is dependent on internal elastic forces and inertia . TherefoMechanical stiffness is commonly assessed in both laboratory and field tests. Regardless of the test mode, any stiffness test must be valid and reliable if the data can be used to inform training decisions. Pappas et al.  reportedThere are several consecutive phases during running distance: start, push-off, acceleration, maximum velocity , and velocity maintenance . All theGround contact can be divided into absorption (braking) and propulsion phases, which differ in their characteristics and purpose . This suThe specific nature of each sport should also be considered in the analysis because running technique used by team sports players (like a “Groucho running”) differs significantly from track athlete technique . It is iMechanical stiffness is a group of variables  that seem to have an important role in running performance. Based on the reported positive relationships between mechanical stiffness and running velocity, a stiffer “leg-spring” should probably increase running performance and contribute to greater mechanical efficiency in running tasks. However, the positive relationship observed between mechanical stiffness and running velocity does not mean that the maximum possible “leg-spring” stiffness will be the most desirable. Therefore, while determining what is desired “leg-spring” stiffness value during running is perhaps the ultimate goal of such research; “optimal” stiffness values may differ somewhat based on differences in the individual, environment and exact running task performed in accordance with the constraints led approach to motor control . This maThe number of factors influencing mechanical stiffness during running makes it difficult to formulate clear and general conclusions about training recommendations. All three levels of constraint effecting the individual, environment, or task constraints including age, gender, running technique, sporting background, fatigue, running distance, and running surface should be taken into account. Until researchers investigate how mechanical stiffness can be altered with different forms of training, the influence of “leg-spring” stiffness on running performance will remain somewhat unclear. It seems that studies focusing on the analysis of local tissues  as well as more global phenomenon including the interaction of the central nervous and peripheral systems and how the plasticity of these systems affects their interplay with regard to “leg-spring” stiffness on running performance may allow for a better understanding of the running mechanics.


Many previous studies have examined the effects of Covid-19 on small-medium enterprises but never discussed how to accelerate small-medium enterprise performance. This study aims to accelerate the recovery of small-medium enterprise performance affected by Covid-19. This research type is interpretive qualitative, data validity test using credibility and transferability test, data analysis technique using research data reduction, presenting data, and drawing conclusions. The conclusions obtained in this study are financing coming from non-banks when the Covid-19 pandemic conditions are very beneficial for small-medium enterprises, and small-medium enterprises are still able to compete globally. The Covid-19 pandemic and the government’s policies have resulted in a decrease in SMEs’ performance. This event is a big problem for SMEs due to the drastic decline in performance, and SMEs can no longer compete at the international marketing level. This research is fundamental to do if it will not cause bankruptcy from SMEs and will cause a more significant effect on the unemployed.It is necessary to determine traditional financing for small- and medium-sized micro-enterprises already widely available. They can no longer support SMEs because of their complicated requirements, including funding derived from the combined capital Rossi, . AnotherIn the Covid-19 pandemic event, SMEs are generally only able to provide less than one-third of the required working capital, as additional money is needed .Competition pressures also arise due to the lack of accurate and up-to-date information about market opportunities in Bank Indonesia’s Role Small Medium Enterprise (SMEs). Profile in supporting the performance of micro, small, and medium enterprises development companies and abroad . The use of crucial informants intended to allow researchers to obtain complete and more holistic information and some five experts in financing as a snowball for supporting information  cannot withstand the decline in people’s purchasing power.Unlike other large companies, unique SMEs’ characteristics require a particular model form that accommodates their uniqueness. Most SMEs are feasible but not bankable. Possible here, SMEs in business meet all the requirements to get additional capital from banking because SMEs can profit regularly from the business activities. But bankable, SMEs become not bankable because most SMEs do not meet the banking authorities’ administrative requirements, especially regarding the financial bookkeeping system. So, it needs a unique financing model that can accommodate the interests of SMEs.For banks, the desire of SMEs to obtain financing becomes challenging to agree. This is because the banks are unable to monitor and focus on marketing, production, and managerial assistance. The policy and operational standards of procedures owned by banks do not allow to adopt all the wishes of SMEs, let alone coupled with the human power owned by banks which is very minimal when compared to SMEs that need to be served.We also ask about the decrease in the competitiveness of SMEs due to the Covid-19 pandemic conditions.In the era of industry 4.0, all entrepreneurs required to digitalization to compete, marketing or their part that has the role of selling all products owned, but as it is known that the resources owned by SMEs are less maximal so that they are not able to compete . It is known that every company has a corporate social responsibility programme.Many alternatives can do to solve (Cusmano & Thompson, Based on Sriyono et al.’s  preliminThe expert’s opinion concludes that the appropriate financing is financing derived from community social development fund, known as corporate social responsibility. Through the funding, it is expected that SMEs could accelerate innovation (Kuratko et al., Based on the results of in-depth interview and search Library, Covid-19 pandemic has a big impact on SMEs namely the decrease in purchasing power, decreased revenue, and the decrease in competitiveness and SMEs do not have additional capital to do activities again. Therefore, it is necessary to provide the appropriate financing to overcome this, namely cooperation with the company to obtain funds derived from the fund of corporate social responsibility, because these funds do not require complex requirements. Also, severe education and assistance are needed for SMEs to change the sales system using digital marketing.Based on the results of in-depth interviews and searches Library, Covid-19 pandemic has a significant effect on SMEs: the decrease in purchasing power, decreased revenue, and the decline in competitiveness and SMEs do not have additional capital to do activities again. Therefore, it needs appropriate financing to overcome this, namely, cooperation with companies to obtain funds derived from corporate social responsibility funds, because the funds do not require complex requirements. Also, severe education and mentoring are needed for SMEs to change the sales system using digital marketing.


Arabidopsis thaliana was employed to demonstrate, for the first time, the alterations in starch granule size and morphology that occur both throughout the day and during leaf aging. Several starch-related mutants were included, which revealed differences among the generated granules. In ptst2 and sex1-8, the starch granules in old leaves were much larger than those in young leaves; however, the typical flattened discoid morphology was maintained. In ss4 and dpe2/phs1/ss4, the morphology of starch granules in young leaves was altered, with a more rounded shape observed. With leaf development, the starch granules became spherical exclusively in dpe2/phs1/ss4. Thus, the presented data provide new insights to contribute to the understanding of starch granule morphogenesis.Transitory starch plays a central role in the life cycle of plants. Many aspects of this important metabolism remain unknown; however, starch granules provide insight into this persistent metabolic process. Therefore, monitoring alterations in starch granules with high temporal resolution provides one significant avenue to improve understanding. Here, a previously established method that combines LCSM and safranin-O staining for in vivo imaging of transitory starch granules in leaves of  Arabidopsis thaliana starches [Transitory starch exists as granules in the chloroplasts of autotrophic tissues and organs; its metabolism provides the most fundamental source of carbon and energy for plant growth and development. The starch granule is a highly organized particle with a semicrystalline structure that consists of two biopolymers: amylopectin and amylose . The glustarches . Amylosestarches ,3. TransArabidopsis thaliana [ptst2, a single starch granule per chloroplast was observed, suggesting that PTST2 is also involved in starch initiation. Both ptst2 and ss4 revealed a greater accumulation of starch per granule. Interestingly, a lack of SS4 not only changed the number of starch granules but also their shape from the typical flattened discoid morphology to one that was much more spherical. This alteration does not occur in ptst2; the granules in ptst2 were larger but still flattened [Over recent decades, starch synthesis and degradation have been extensively studied; however, starch granule initiation remains largely obscure ,3,4,5. Athaliana . An SS4-thaliana . In the lattened ,8.dpe2phs1 mutant, lacking both PHS1 and Disproportionating Enzyme 2 (DPE2), was also found to have a single starch granule per chloroplast with a more spherical morphology than that seen in ss4. However, starch granules were only observed in young leaves and no starch was detected in old leaves [dpe2phs1 was not reduced, suggesting an unknown pathway influenced by PHS1 and DPE2 that can affect starch initiation independently of SS4 deficiency [dpe2phs1 resulted in aggravated granule morphology, becoming near-perfectly spherical, which implies that SS4, PHS1, and DPE2 work in parallel to influence starch granule morphology via a mechanism that remains to be elucidated.The plastidial protein Phosphorylase 1 (PHS1), another glucan-forming enzyme, elongates glucan chains that have a degree of polymerization of four DP4) or greater [ or greatd leaves ,10. DPE2d leaves ,12,13. Tficiency ,10,14. Ssex1-8, the mutant lacking Glucan Water Dikinase (GWD), has an unusual granule morphology: the starch granules are deformed and thin with irregular edges [sex1-8 were concluded to occur as a consequence of uneven metabolism at the starch granule surface. Supportive of this hypothesis, the smaller granules revealed a more even size and morphology than those of the larger ones [In addition to the three abovementioned mutants, ar edges . GWD usear edges ,16. GWD ar edges . The irrger ones .The starch granules reflect and integrated various metabolic processes taking place during synthesis and degradation. Thus, understanding the factors that influence starch granule morphology and size allows getting insights into the entire starch metabolism. Further, starch parameters as size and shape are important for the usage of starch, especially for industrial purposes, as adapted parameters are needed for specific applications.Much of the obtained data pertaining to starch granule morphological parameters were limited to specific time points. Due to analytical limitations, it was impossible to monitor alterations in the granule size and morphology within the diurnal cycle and during leaf development. The analysis of starch granules in their natural environment—without purification—is of significant interest and may lead to a more complete description of the granule parameters.ptst2. The ratio of the minimum to the maximum diameter allows one to estimate alterations in the morphology. In this regard, ptst2 presented larger starch granules with the typical flattened discoid morphology [ptst2 starch granules increased from 3.68 ± 0.83 μm and 1.45 ± 0.23 μm to 5.03 ± 1.04 μm and 1.80 ± 0.24 μm, respectively  than the maximum diameters  did, which implies that the starch accumulated more in the plane of thickness. The ratio of the diameters in ss4 increased from 0.66 ± 0.1 to 0.82 ± 0.1  as they are time-consuming and require many materials and complex sample preparation. Previously, starch granules of the wild type and several starch-related mutants were detected in vivo using laser confocal scanning microscopy (LCSM)-based imaging combined with safranin-O staining. This method was easily and flexibly employed to observe starch granules in different cell types . Starch parameters such as the number of starch granules per chloroplast, size, and morphology were described . Using Lrphology . Althougectively C, the ray  and 1.52 μm (62%), respectively  did not demonstrate the typical morphology of Col-0 or ptst2, which means that the minimum diameter cannot reflect the exact thickness of starch granules as their orientation cannot be easily determined. Thus, SEM remains the method of choice to determine the exact appearance of starch granules in vitro and to confirm the potential morphological alterations indicated by LCSM.Tracking and estimating the size and morphological alterations in starch granules of relevant mutants could provide insight into the underlying molecular mechanisms. Here, we showed for the first time that increases in starch granule size can be monitored during daily starch synthesis for the wild type and some starch-related mutants. Furthermore, we were able to visualize morphology changes during leaf aging. This is the first step toward a deeper analysis of the underlying mechanisms that affect starch morphology. LCSM with safranin-O staining provided the basis for this ability. In our previous studies , we demosex1-8 were presented for the first time in this study  indicate that even potential small alterations in starch synthesis and degradation parameters can, over time, massively influence starch granule morphology, potentially because these small alterations are sustained when starch granules were not totally degraded by the end of the night.The data also clearly indicate that alterations in degradation—as, for example, in the case of Arabidopsis thaliana seeds were sterilized by 70% (v/v) ethanol and 6% (v/v) hypochlorous acid with 0.02% (v/v) Tween 20 and sown on 0.8% (w/v) agar plates with Murashige and Skoog (MS) medium and no sucrose, pH 5.7. The plates were vernalized in darkness at 4 °C for three days. Seedlings were transplanted to soil after a one-week growing period in an illumination incubator with a light/dark regime . Plants were grown in a chamber under the same conditions until sampling. ptst2 and sex1-8, of Col-0 origin, were described previously [SALK_096130; Col-0) was obtained from the Salk Institute Genomic Analysis Laboratory. Homozygosity was confirmed by PCR (forward primer (Lp): 5-CTTCTGGAAGAACAGTTAGAGAAGCTT-3 and reverse primer (Rp): 5-GAATGGAGTCCTTTTCCTCCC-3; T-DNA specific primer LBb1.3: 5-ATTTTGCCGATTTCGGAAC-3). Genotypical confirmation was performed for ss4 and dpe2phs1ss4 as their Col-0 origin was not previously reported  Triton X-100) and filtered through Miracloth  before the filtrate was centrifuged at 4 °C, 1500× g for 5 min. Supernatants were discarded and the sediments were resuspended in 40 mL extraction buffer, which was filtered through 100 μm and 30 μm meshes before the filtrate was centrifuged as described above. The resulting sediments were again resuspended in 2 mL extraction buffer and slowly pipetted onto 5 mL Percoll  and centrifuged at 4 °C, 1500× g for 15 min. The supernatants were discarded and the sediments/starch granules were washed with water three times and finally dried in a SpeedVac.Leaves of the wild type and mutants were separately collected and classified according to their age as young, mature (not shown), or old leaves when the whole plants were 4 weeks old. The leaf materials were frozen in liquid nitrogen and ground into a fine powder with a mortar and grinding mill. The powder was suspended in 40 mL extraction buffer (20 mM HEPES-KOH, pH 7.4, 0.4 mM EDTA, and 0.05% (SEM observation was performed as described previously .Native PAGE for the detection of DPE2 and PHS1 activity was performed as described in .


This study aimed to investigate the proximate composition, mineral content, functional properties, molecular structure, in vitro starch digestibility, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity  of green banana flour (GBF) cultivars grown in South Africa. With proximate composition, Finger Rose and Pisang Awak had the highest protein (4.33 g/100 g) and fat (0.85 g/100 g) content, respectively. The highest ash content (3.50 g/100 g) occurred with both Grand Naine and FHIA-01 cultivars. Potassium and copper were the most abundant and least minerals, respectively. Pisang Awak cultivar had the highest water absorption capacity (67.11%), while Du Roi had the highest swelling power (0.83 g/g) at 90 °C. Scanning electron microscopy (SEM) images revealed that starch granules from all GBF cultivars were irregular in shape and they had dense surfaces with debris. All the GBF cultivars had similar diffraction patterns with prominent peaks from 15°–24° diffraction angles. The resistant starch (RS) and amylose content of the FHIA-01 cultivar indicates that the GBF has the potential to lower risks of type 2 diabetes and obesity. The highest TPC, TFC and antioxidant activity occurred with the Grande Naine cultivar. Based on their functional characteristics, the Grand Naine and FHIA-01 GBF cultivars could potentially be used as raw materials for bakery products as well as for the fortification of snacks. The diabetes endemic continues to increase associated with obesity, inactive lifestyles and high-energy diets . These dThe use of green banana flour is important as an alternative raw material for the processing of healthy functional products. According to Kumar et al. , green bFlour from five green banana cultivars, namely Grande Naine, Pisang Awak, Finger Rose, FHIA-01 and Du Roi, was kindly provided by the Agricultural Research Counsel (ARC) Tropical and Subtropical Crops, Nelspruit, Mbombela in South African. All reagents were analytical grade, Trolox, Folin–Ciocalteu reagent, gallic acid and quercetin were purchased from Sigma-Aldrich Pty. Ltd. . The resistant starch assay kit and the amylose/amylopectin kit were purchased from Megazyme Ltd. .g for 10 min to remove soluble fiber, and then 1 L NaOH solution  was added to the sediment. The starch sediment was mixed with water and stirred for 5 min before resting for 2 h. Thereafter, the sediment was again suspended in water and allowed to settle. This was repeated until the wash water reached a neutral pH. The resultant material was then dried at 45 °C for 24 h. The desiccated starch was pulverized and passed through a 100 µm sieve.A water-alkaline extraction method was used to prepare banana starch, as described by Jiang et al. , with a The moisture content was assayed using a vacuum oven dryer at 60 °C for 16 h using 2–3 g of sample, according to Rodriguez-Jimenez et al. . A furnaMineral analysis was conducted following a method by Jakavula et al. . BrieflyThe WAC of GBF was determined using the method described by Kumar et al. , with soThe water solubility index and swelling power were determined following the method detailed by Kumar et al. . Green bA scanning electron microscope (SEM-EDX)  was used to study the microstructures of the banana starch granules. The GBF starch samples were placed on aluminum cylinders that had a double-sided tape followed by coating with carbon. The acceleration voltage was 10.00 kV, as previously described by Maziya et al. . An elecThe XRD analysis of the GBF samples was determined using Philips X’Pert XRD equipment . The power source was set at 40 kV and 40 mA power with a scanning interval of 5°/min. The scanning range was 2θ = 5° to 90° .−1 in wavenumbers from 500 to 4000 cm−1 [The ATR-FTIR spectra of GBF samples were measured using a 4000 FTIR spectrophotometer . The functional groups of the isolated compound were detected by ATR  with a diamond crystal plate with a scan rate of 16 runs per scan at a resolution of 4 cm000 cm−1 .The determination of rapidly digestible, slow digestible, resistant, and total starch contents of green banana starch was carried out using a Megazyme Resistant Starch Assay Kit . Briefly, the method involved incubating the GBF sample (80 mg) in a mixture of enzymes (pancreatic α-amylase and amyloglucosidase) in maleate buffer (pH 6.0)  .A commercial amylopectin/amylose kit  was used to quantify amylose content. The principle of the method involves the separation of amylopectin and amylose. Thereafter, amylopectin is precipitated with concanavalin-A (Con A), followed by centrifugation to eliminate it Jiang et al. .v/v, 20:5, respectively) followed by incubation at 37 °C for 4 h with shaking. The mixture was then centrifuged (4000× g for 10 min). Thereafter, the supernatant was mixed with 500 µL deionized water in a test tube with 30 µL standard/extracts and 50 µL Folin–Ciocalteu reagent . This was followed by the addition of 245 µL deionized water and 200 µL of Na2CO3. The sample mixture was then incubated at 27 °C for 30 min, and a microplate reader was used to measure the absorbance (750 nm). Gallic acid was used as standard, and the results were expressed as mg gallic acid equivalent (GAE)/g dry weight using the standard curve (R2 = 0.9982).The TPC was determined using the Folin–Ciocalteu assay method according to the procedure outlined by Blainski et al. . Briefly3 and 20 µL of 2.5% NaNO3. After 5 min, 100 µL of NaOH solution was added to the mixture. From the mixture using a micropipette, 200 µL was pipetted into a microplate (96 well). A microplate reader was used to measure the absorbance (450 nm). The TPC was expressed as mg QE/mg dry weight using the standard curve (R2 = 0.9991).The TFC was determined following the method described by Jabri-Karoui et al. . BrieflyThe antioxidant activity of GBF samples was determined through the use of the ferric-reducing-ability-plasma (FRAP) with slight adjustment as described by Hofmann et al. . The metp ≤ 0.05). The results were shown as means ± standard deviation. The contrast of mean values was analyzed by Fisher Least Significant Difference (LSD) tests. All the experiments were performed in triplicates.One-way analysis of variance (ANOVA) was performed using the Statistica statistical software (Version 13.0/September 2015) for data analysis. The significant difference between the samples was determined at 95% (The proximate composition of green banana flour (GBF) grown in South Africa is shown in p ≤ 0.05) varied from 2.46–3.50 g/100 g d.w., with the Grand Naine cultivar recording the highest ash content. Campuzano et al. [The abundance of minerals in GBF has made it a valuable fruit. In this study, the total ash content statistically . High protein content occurred with the Finger Rose cultivar (4.33%), while the Grand Naine cultivar had the lowest protein content (3.60%). The Grand Naine protein content in this study was comparable with the protein content (3.53%) for the Grand Naine cultivar reported by Kumar et al. [Musa spp.). In the study reported by Ferreira et al. [The protein content of the five GBF cultivars significantly differed  with the lowest fat content recorded for the Du Roi cultivar (0.42 g/100 g d.w.) . The fatp ≤ 0.05) between the content of sulfur (S) amongst the five GBF cultivars. With essential minerals, calcium (Ca) was the least abundant mineral with the lowest concentration observed in the Finger Rose (8.70 mg/100 g) cultivar.The mineral profiles of GBF used in this study are shown in p < 0.05) varied from 0.25–5.0 mg/100 g, with the Grande Naine cultivar showing the highest concentration. The concentration of manganese (Mn) ranged from 0.48–3.2 mg/100 g, and the highest and lowest concentrations were observed in Grande Naine and Du Rio cultivars, respectively. Interestingly, the mineral composition of the soil has been reported to influence the mineral content of food crops [As expected, the overall concentration of macro-minerals was higher than that of trace minerals. The Grande Naine cultivar recorded the highest (2.88 mg/100 g) concentration of iron (Fe), while Finger Rose recorded the lowest (1.50 mg/100 g). The concentration of Fe and Zn reported in the present study was lower than that reported by Ferreira et al.  who repood crops . Furtherod crops ,39.The WAC indicates the volume occupied by starch granules after swelling in excess of water . It is aThe solubility and swelling power are parameters used to investigate the quality of starch granules. The solubility index is linked to the soluble solid contents in flour, whereas swelling power is a measure of the retention of starch granule integrity when subjected to high cooking temperatures ,41. HereThe SEM images of starch isolated from GBF are shown in According to Pandey et al.  the fragThere is a semi-crystalline nature of starch particles that can be assessed by XRD. In this study, the crystalline structure of green banana starch granules was analyzed using XRD, as shown in −1 and 1002.80 cm−1 show the occurrence of hydroxyl (–OH), amine groups (–NH) and carbonyl group (=C=O) bonds, respectively [−1 are defined as the fingerprint region [−1, bands between 990 cm−1 and 1160 cm−1, attributed to carbonyl group (=C=O) bonds stretching. These compounds may contribute to the characteristic flavor and order of the banana flour. For all the analyzed banana flours, bands in similar regions were observed. Similar results have been reported elsewhere in the literature [The FTIR analysis was performed to identify various characteristic functional groups present in the Grande Naine, Finger Rose, Du Roi and Pisang Awak green banana flours as shown in ectively . The chaectively ,47,49. Iterature .p ≤ 0.05) in their RDS, SDS and RS. Du Roi had the lowest RDS of 4.46%, while Grande Naine (6.02%) had the highest amount of RDS. The SDS ranged from 10.17% (FHIA-01) to 14.87% (Finger Rose). FHIA-01 had the highest amount of resistant starch (RS) (86.50%), while Grande Naine had the lowest amount of RS (80.38%). It is widely acknowledged that the GI and RS contents are two significant indicators of starch digestibility [Since humans generally consume cooked starch more than raw starch, the digestion performance of cooked banana starch is more important to the food industry. The digestibility fractions of green banana starch are indicated in tibility ,50 Thesetibility  on the Gtibility . Recentltibility .p < 0.05) variation in amylose content was observed, with the FHIA-01 cultivar showing the highest amylose content (24.82%) and Finger Rose recording the lowest amylose content (15.55%). It was also noted that the flours with high amylose content appeared to have high RS content. Thus, we propose that the amylose content could somewhat be positively correlated to the resistant starch. Flour with a higher amylose content is known to have a high solubility index since the amorphous region of starch granules primarily contains high amylose content [There are several properties that are affected by how amylose and amylopectin are arranged in GBF. These include gelatinization, retrogradation as well as digestibility ,51. Here content ,53. Prev content ,55,56 sup < 0.05) varied (The TPC of GBF cultivars studies here significantly  varied . Grand NThe antioxidant capacity of GBF is shown in The varying functional and physicochemical properties of the GBF cultivars suggest that they can be utilized as raw materials in different food products. The morphological characteristics of the GBF starch and the fact that it appears to be linked to high WAC suggest their possible application in the development of edible films. The GBF were all found to contain relatively high RS, which makes them suitable for the development of low-GI food products. The high TPC, TFC and antioxidant activity in the Grand Naine cultivar suggests its possible use in health-promoting food products. Green banana flour cultivars, such as Pisang Awak, FHIA and Du Roi, indicate that they could be stable when added to food that is processed at a high temperature due to their high amylose content. While, on the other hand, Grand Naine and Finger Rose have low amylose content, which suggests a possible use in food products with low thermal characteristics.


O artigo “Alterações da Rigidez Arterial em Pacientes com Estenose Aórtica Grave Submetidos à Cirurgia de Troca Valvar” traz informações importantes sobre o comportamento da rigidez arterial antes e após a troca valvar aórtica.>pressure wave velocity) carótida-femoral, medida através do aparelho Complior Analyse para estudar a rigidez arterial. Outros métodos poderiam ter sido utilizados, como medidas do cateter de pressão invasiva, ressonância magnética e sensores de manguito periféricos, mas a PWV é o padrão-ouro.Eles estudaram 150 pacientes com estenose aórtica grave submetidos à troca valvar aórtica com bioprótese. Eles utilizaram um método não invasivo, a velocidade da onda de pressão  no pós-operatório. Eles postularam que a obstrução a montante pode interferir nas medidas, mascarando os efeitos reais na aorta. Yotti et al.,O estudo apresenta algumas limitações: centro único, retrospectivo, variabilidade quanto ao tempo de medidas pós-operatórias, falta de randomização, pequeno tamanho da amostra e variabilidade dos dados de acordo com o estado do paciente.Singh et al.,O impacto do estudo da rigidez arterial merece atenção especial, pois modificações na parede arterial levarão ao aumento da rigidez arterial, que pode ser responsável pelo envelhecimento vascular acelerado e hipertensão arterial; além disso, a rigidez arterial foi incorporada à estratificação de risco de lesões subclínicas de órgãos-alvo.Como os autores  The paper “Arterial Stiffness Changes in Severe Aortic Stenosis Patients Submitted to Valve Replacement Surgery” has important information on the behavior of arterial stiffness before and after aortic valve replacement.They studied 150 patients with severe aortic stenosis submitted to aortic valve replacement with bioprosthesis. They used a noninvasive method, carotid-femoral pressure wave velocity (PWV) measured through Complior Analyse, to study arterial stiffness. Other methods could have been used, such as invasive pressure catheter measurements, MRI and peripheral cuff sensors, but PWV is the gold standard.Aging, hypertension and atherosclerotic disease contributes to the increase in vascular stiffness as measured by PWV and are confounding factors. Their patients’ mean age was 72± 8 years, hypertension was present in 83%, dyslipidemia in 76%, diabetes in 35% and 24% had a history of smoking.There was an inverse association between arterial stiffness and the left ventricle-aortic gradient in the preoperative patients. After aortic valve replacement, there was a significant increase in arterial stiffness measured by PWV, being 9.0± 2.1 m/s in the preoperative and 9.9±2.2 m/s (±2.2 months after surgery) in the postoperative period. They postulated that the upstream obstruction might interfere with the measurements, masking the real effects on the aorta. Yotti et al.The study has some limitations: single center, retrospective, variability regarding the time of postoperative measurements, lack of randomization, small sample size and variability of data according to patient status.Singh et al.,The impact of studying arterial stiffness deserves special attention, as modifications in the arterial wall will lead to an increase in the arterial stiffness, which may be responsible for accelerated vascular aging and arterial hypertension; moreover, arterial stiffness have been incorporated into the risk stratification of subclinical target organ lesions.Another problem that is sometimes associated with aortic stenosis is the need to replace the ascending aorta with a graft, or implant an endograft in the ascending, descending aorta or aortic arch. de Beaufort et al, in an experimental study with 20 patients with porcine aortas, demonstrated that PWV was significatively increased after stent graft deployment.As the authors


The effect of bone marrow mesenchymal stromal cells (BMSCs) and platelet-rich plasma (PRP) on tendon allograft maturation in a large animal anterior cruciate ligament (ACL) reconstruction model was reported for the first time. It was hypothesised that compared with non-augmented ACL reconstruction, BMSCs and PRP would enhance graft maturation after 12 weeks and this would be detected using magnetic resonance imaging (MRI).n = 5). Group 1 received 10 million allogeneic BMSCs in 2 ml fibrin sealant; Group 2 received 12 ml PRP in a plasma clot injected into the graft and bone tunnels; and Group 3 (control) received no adjunctive treatment. At autopsy at 12 weeks, a graft maturation score was determined by the sum for graft integrity, synovial coverage and vascularisation, graft thickness and apparent tension, and synovial sealing at tunnel apertures. MRI analysis  of the signal–noise quotient (SNQ) and fibrous interzone (FIZ) was used to evaluate intra-articular graft maturation and tendon–bone healing, respectively. Spearman’s rank correlation coefficient (r) of SNQ, autopsy graft maturation score and bone tunnel diameter were analysed.Fifteen sheep underwent unilateral tendon allograft ACL reconstruction using aperture fixation and were randomised into three groups (p = 0.01) and PRP group (p = 0.03) had a significantly higher graft maturation score compared with the control group. The BMSC group scored significantly higher for synovial sealing at tunnel apertures (p = 0.03) compared with the control group. The graft maturation score at autopsy significantly correlated with the SNQ . The tunnel diameter of the femoral tunnel at the aperture  and mid-portion  positively correlated with the SNQ.The BMSC group (BMSCs and PRP significantly enhanced graft maturation, which indicates that orthobiologics can accelerate the biologic events in tendon allograft incorporation. Femoral tunnel expansion significantly correlated with inferior maturation of the intra-articular graft. The clinical relevance of this study is that BMSCs and PRP enhance allograft healing in a translational model, and biological modulation of graft healing can be evaluated non-invasively using MRI. Graft healing after ACL reconstruction consists of tendon–bone healing and matrix remodelling (“ligamentisation”) of the intra-articular graft , 15. GraThere is a growing body of literature exploring biological modulation of graft healing . MesenchThe clinical relevance of this study is that it represents the first large animal ACL reconstruction study to report the effects of BMSCs and PRP on allograft healing. The purpose of this study was to compare the effect of BMSCs and PRP on tendon allograft maturation in a large animal model, and to determine if MRI can be used to identify biological modulation of graft healing. The hypothesis was that BMSCs and PRP would enhance graft maturation after 12 weeks, and graft maturation at autopsy would correlate with graft maturation on MRI.n = 5 animals per group). In group 1, 10 million allogeneic BMSCs in fibrin sealant  were applied to the graft (2 million) and bone tunnels (4 million per tunnel). In group 2, 12 ml of PRP was injected into the graft (4 ml) and the bone tunnels (4 ml per tunnel). The control animals in Group 3 received no treatment. Post-operatively animals were euthanised after 12 weeks. Graft maturation was examined using MRI and a macroscopic scoring system at autopsy.The research was conducted in accordance with a Project License protocol accepted under the UK Home Office Animals (Scientific Procedures) Act 1986 (licence number PF16F4AA0A). This study was approved by the animal warfare review board at the Royal Veterinary College. Fifteen full-mouthed female lowland Mule sheep  were included. Animals were randomised into three groups (Endoret®(prgf®) Technology . 72 ml of venous blood was obtained in 9 ml tubes containing 3.8% (wt/vol) sodium citrate. The tubes were centrifuged twice for 8 min at 580 G (1902 rpm) at room temperature. The 2 ml of plasma located above the buffy coat was collected, with a total PRP volume of 16 ml per animal  incubator. After 72 h, the media was discarded, and fresh growth media was added to supplement the cells that had attached to the flask. The cells were detached with 0.25% trypsin–EDTA  when they had reached 90% confluence. The BMSCs were sub-cultured and the growth media was changed every 3 days. 10 million, passage 3–4 cells were used in each surgical procedure. Tri-lineage potential—adipogenesis, osteogenesis, and chondrogenesis—of the cells was confirmed in vitro prior to surgery.Bone marrow was aspirated from an adult sheep (age 2 years). 10 ml of bone marrow was aspirated from two regions of the iliac crest into a 20 ml polypropylene tube containing 10,000 International Units (IU) heparin sodium . The aspirate was combined with standard growth media, which was high glucose Dulbecco’s modified Eagle’s medium (DMEM) , 10% FCS  and 1% penicillin–streptomycin (ThermoFisher). The aspirate was plated onto T-150 culture flasks and cultured at 37 °C in a 5% carbon dioxide (COSDFT were harvested from sheep (age 2–3 years) using a previously described technique . The gra. The stifle joint was taken through ten full ranges of motion. Tibial fixation was achieved with the stifle joint in full extension with an 8 × 25 mm Biosure PEEK interference screw . A tension of 40 N was applied because this tension has been used in previous ovine studies . Gra. Gra5]. U tests were used to compare treatment groups with the control. Inter-rater reliability as assessed using Kappa statistics. The interpretation was as follows: < 0.40 was poor, 0.40–0.59 was fair, 0.60–0.74 was good, and ≥ 0.74 was excellent [r). Significance was assumed at the 0.05 level. Previous animal studies of ACL reconstruction similar to this have used a n = 5 [p value of 0.05, a n = 5 has been shown to produce significant results.IBM SPSS Statistics for Windows, version 26  was used. Data was not normally distributed and reported as medians and interquartile ranges. Mann–Whitney There was no evidence of joint instability or an adverse effect to the treatments. Minimal chondral degeneration and mild synovial inflammation was observed. All the grafts were intact at the time of dissection. The PRP and BMSC treated grafts had remodelled into ACL-like structures. In contrast, grafts from the control group appeared atrophic with minimal vascularisation Fig. .Fig. 5Aup = 0.01) and PRP control (p = 0.03) had a significantly higher scores on average compared with the control group , which is considered excellent. In terms of the overall graft maturation score, the BMSC group p = 0.01)p = 0.03)  Fig. d. No staGraft maturation was higher in BMSC and PRP groups as evidenced by MRI maturation score and SNQ. The average graft diameters in the BMSC and PRP groups were higher than the control group. The intra-articular graft demonstrated higher signal intensity in the control group compared to the PRP and BMSC group.Tendon–bone healing next to the screws was superior to healing at the apertures in all cases in the femur. In the tibia, tendon–bone healing next to the screws was superior to healing at the apertures in all cases except the PRP group where healing was the same at the aperture and adjacent to the screw.The apertures in the control group were wider than seen in the other two experimental groups, and were filled with hyperintense material Fig. d Table .Table 3Tr = − 0.83, p ≤ 0.01).The autopsy graft maturation scores and the MRI graft maturation score were significantly inversely correlated  and mid-portion . No significant correlations were seen between the tibial tunnel diameter and SNQ  was also verified.BMSCs have potential to modulate graft healing because of their capacity for multi-lineage differentiation and diverse paracrine effects . This stThe effect of local PRP application from coated sutures has been reported in sheep  but to oMRI is a popular technique to evaluate ACL graft maturity after surgical reconstruction . We demoThis study has several limitations. First, graft healing is a complex process that occurs over many months  but our BMSCs and PRP significantly enhanced tendon allograft maturation after 12 weeks in a translational large animal model compared to an untreated control. MRI could be used to non-invasively examine biological augmentation of ACL graft healing in clinical practice.


Our current work seeks to provide direct empirical evidence on whether Chinese international students’ experiences studying abroad promote dialectical thinking. We collected behavioral data from 258 Chinese international students studying in multiple regions. We found that there was a main effect among the four conditions . More specifically, when primed with studying abroad or typical day (relative to hometown culture), participants were more likely to show tolerance for contradiction by deeming both sides of contradictory scientific statements as convincing and rating them more favorably. Therefore, it is plausible that Chinese international students’ experiences studying abroad promote their dialectical thinking. More work is needed to further this line of research by (1) extending these effects with other measures of dialectical thinking such as perception of interconnectedness and prediction of change, (2) adopting differing paradigms to provide more robust findings, and (3) probing the underlying processes as to why experiences studying abroad promote dialectical thinking. International education has been flourishing for several decades as the process of globalization has broadened and deepened. According to Open Doors Data from the Institute of International Education, China has become the leading source of international students in Western countries . For exaIncreasing number of individuals hold multicultural experiences as they engage in differing cultural contexts or interact with people from differing cultural backgrounds. Cultural psychologists contend that the impacts of individuals’ multicultural experiences on their mental processes and behavioral patterns are mixed, paradoxical, and even seemingly contradictory . Past woSince the two renowned cultural] psychologists Dialectical thinking consists of three core principles: principle of change , principle of contradiction , and principle of holism  . First, There is some research gap in the current literature. First, despite the huge numbers and rapid rate of increase of Chinese international students across the globe, empirical research on the psychological antecedents and consequences of studying abroad, especially theoretical formulation and empirical work on how and why studying abroad experiences might reshape their psychological processes and behavioral patterns has been limited. More work is clearly needed to better our understanding on International students’ multicultural experiences would alter their way of thinking, feeling, and behaving. Second, previous work has examined the psychological impacts of individuals’ multicultural experiences on their creativity, generalized trust, personality development, self-efficacy, and outgroup prejudice, etc. Extant work, however, has not looked at how Chinese international students’ multicultural experiences affect their thinking styles in general and dialectical thinking in particular. Third, although a large amount of work has looked at between-culture variations and within-culture variations on dialectical thinking, no prior work has examined how and why individuals’ multicultural experiences would shift around dialectical thinking in a dynamic manner, taken together, despite the growing body of work pertaining to the psychological outcomes of multicultural experiences, mental health and psychological well-being of Chinese international students and the large body of work on dialectical thinking, there has been little work directly looking at how and why Chinese international students’ multicultural experiences affect their systems of thought and dialectical thinking. Our current work therefore sought to reduce this research gap by directly examining how Chinese international students’ experiences studying abroad in diverse regions would influence their system of thought.Past research has well-documented cultural differences in tolerance for contradiction. Peng and Nisbett observed that members of East Asian  are more likely to display tolerance and acceptance of conflicting elements or events. As they have articulated in their article, they asserted that “holistic thinkers tend to engage in reasoning involving contradictions that tolerate opposites, whereas analytic thinkers tend to engage in reasoning involving contradiction that chooses one of two opposing propositions . Little We propose two plausible research hypotheses. Considering that the cultural mobility patterns of Chinese international students are from China to mostly Western countries such as United States, United Kingdom, Canada, Germany, and Australia, etc., it is plausible that Chinese international students would adopt those cultures’ typical way of thinking, which is analytical thinking, as the acculturation process broadens and deepens. Conversely, it is also likely that studying abroad experiences make Chinese international students endorse multiple cultural perspectives which are to some extent incompatible and contradictory. Therefore, they have to adopt dialectical thinking to meet the needs of the demanding acculturation process. We therefore make the following two competing predictions:H1:Priming studying abroad experiences encourage Chinese international students to show greater tolerance for contradiction, relative to priming exposure to foreign culture, hometown culture, and control condition.H2:Priming studying abroad experiences encourage Chinese international students to show less tolerance for contradiction, relative to priming exposure to foreign culture, hometown culture, and control condition.Based upon extant work and our theoretical formulation, we argue that the second hypothesis is more theoretically plausible. Existing work has found that multicultural experiences can enhance cognitive complexity, increase openness personality, and reduce outgroup bias. One of the core features of dialectical thinking is tolerating contradictions, which represents that two things or two viewpoints that seem contradictory can co-exist and be compatible with each other. Therefore, we infer that when individuals encounter or interact with foreign cultural members, their cognitive flexibility and openness to experiences will likely increase. Thus, their degrees of tolerance for contradictions may be enhanced through increased integrative complexity . AlternaThrough an online platform we recruited 265 Chinese international students who are currently studying abroad in diverse regions. Participants were mainland Chinese students who were currently pursuing varying degrees  in differing cultural regions . Our experiment was divided into three parts. The first part was cultural priming procedure. Based on previous work , we adapM = 3.55, SD = 0.76, Range = 0–6) and likeability . We then conducted an ANOVA analysis. The results suggested that participants were more tolerant of contradictory scientific statements when primed with studying abroad experiences or typical day relative to hometown culture. In other words, when participants were manipulated to mentally stimulate the host culture in which they are currently studying, their degree of tolerance for conflicting viewpoints increased, at least temporarily. More specifically, they reported that two seemingly conflicting statements could co-exist and did not contradict each other. In other words, they reported that the two seemingly conflicting scientific findings were indeed both convincing, F = 2.95, p < 0.05 and likeable, F = 3.01, p < 0.05 , as well as the difference between typical day and hometown culture  was significant. For likeability, the difference between studying abroad and hometown culture , as well as the difference between typical day and hometown culture  was significant. It is worth noting that the differences between priming studying abroad and priming typical day did not yield any meaningful results which was unexpected from our original theoretical formulations. We speculate that it is highly likely that priming typical day for the group of Chinese international students while they are studying abroad is naturally similar to priming their everyday life during studying abroad, which makes this control condition serve an equivalent function of priming studying abroad. Therefore, we deem both conditions as our experimental conditions and treat typical day priming as analogs as studying abroad priming. We did find that relative to hometown culture, participants were more likely to display dialectical thinking when primed with studying abroad or typical day.A total of 265 Chinese international students participated in our experiment. After deleting those who failed the attention check items , 258 participants were included in our final analyses. According to Our current work is among the first to provide direct evidence to partially support the claim that Chinese internationals students’ studying abroad experience promotes dialectal thinking. Our data suggests that Chinese international students are more likely to accept contradictory scientific statements when primed with studying abroad experiences (comparing to priming with hometown culture). We have also observed consistent evidence between the two indicators of tolerance for contradiction: convincingness and likeability, meaning that Chinese international students are more likely to believe that the two seemingly conflicting scientific statements are both persuasive and rated them more favorably.Why would priming studying abroad experiences enhance tolerance for contradiction? Previous work indicates that priming the yin-yang symbol among European Americans lead them to anticipate more changes in judgments and behaviors . This fiOur work has important contributions to the extant literature. First, past work has not looked at whether multicultural experiences could affect individuals’ ways of thinking. Our findings are among the first to demonstrate that studying abroad experiences does have an impact on Chinese international students’ dialectical thinking, specifically tolerance for contradiction. Second, our work adds to the growing literature that psychological outcomes of Chinese international students’ studying abroad experiences is not limited to academic achievements and mental health domains. Studying abroad experiences may elicit profound changes in International students’ cognitive, emotional, motivational and behavioral processes. Third, although cultural differences in dialectical thinking have been well-documented, dialectical thinking is a dynamic, flexible, and malleable construct. Dialectal thinking can therefore be shifted around even by subtle experimental manipulations. Our work has shed new light on the intersection among multicultural experiences, International students, and dialectical thinking. As we live in the era of globalization, more work is clearly needed to probe the important research question: how and why do multicultural experiences reshape individuals’ way of thinking, feeling, and behaving.Some limitations also apply to our work. First, due to the difficulties of collecting data during the COVID-19 outbreak, our limited sample size reduced our statistical power. Future replication efforts should use a larger sample size to detect those effects. Second, as we only examined one of three indicators of dialectal thinking, future work should determine whether Chinese internationals students’ expectation of change and perception of interconnectedness can also be altered by priming studying abroad experiences. Third, since human behavior is the product of complex interactions between personal dispositions and contextual factors, future work should examine whether Chinese international students’ personality characteristics or cultural identity play a role in moderating the effects of multicultural experiences on their mental processes and behavioral patterns.Drawing upon a cultural priming experiment, we observed that Chinese international students were more likely to show tolerance for contradiction when they were primed with their host culture rather than primed with their home culture. Future work should examine the psychological underpinnings of this effect, potential mediators and boundary conditions, which we hope will encourage researchers, educators, and policy makers to facilitate both basic research and applied work in the domain of international education.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by the Department of Psychology, Tsinghua University. The patients/participants provided their online versions of informed consent to participate in this study.XH designed and carried out the study, collected and analyzed the data, and wrote the manuscript. YW and SL assisted with data collection. KP refined the research idea, supervised the study, and revised the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Preoperative evaluation of aggressiveness, including tumor histological subtype, grade of differentiation, Federation International of Gynecology and Obstetrics (FIGO) stage, and depth of myometrial invasion, is significant for treatment planning and prognosis in endometrial carcinoma (EC). The purpose of this study was to evaluate whether three-dimensional (3D) magnetic resonance elastography (MRE) can help predict the aggressiveness of EC.From August 2015 to January 2019, 82 consecutive patients with suspected uterine tumors underwent pelvic MRI and MRE scans, and 15 patients with confirmed EC after surgical resection were enrolled. According to pathological results , the patients were divided into two subgroups. The independent-samples t-test or Mann-Whitney U test was used to compare the stiffness between different groups. The diagnostic performance was determined with receiver operating characteristic (ROC) curve analysis.n = 6) myometrial invasion was significantly higher than that with < 50 % (n = 9) myometrial invasion . Using a stiffness of 3.04 kPa as a cutoff value resulted in 100 % sensitivity and 77.8 % specificity for differentiating ≥ 50 % myometrial invasion from < 50 % myometrial invasion of EC. The stiffness of poorly differentiated EC (n = 8) was significantly higher than that of well/moderately differentiated EC (n = 7) . Using a stiffness of 3.04 kPa as a cutoff value resulted in 75 % sensitivity and 71.4 % specificity for differentiating poorly differentiated from well/moderately differentiated EC. The stiffness of FIGO stage II/III EC was significantly higher than that of FIGO stage I EC . Using a stiffness of 3.04 kPa as a cutoff value resulted in 100 % sensitivity and 70 % specificity for differentiating FIGO stage I EC from FIGO stage II/III EC. The tumor stiffness value in type II (n = 3) EC was higher than that in type I (n = 12) EC (3.67 ± 0.59 kPa vs. 2.88 ± 0.85 kPa), but the difference was not significant (p = 0.136).The stiffness of EC with ≥ 50 % (Tumor stiffness measured by 3D MRE may be potentially useful for predicting tumor grade, FIGO stage and myometrial invasion of EC and can aid in the preoperative risk stratification of EC. Endometrial carcinoma (EC) is one of the most common primary malignant tumors in women, and its incidence is steadily rising worldwide . PreoperRecently, magnetic resonance elastography (MRE) has emerged as a noninvasive technique for evaluating tissue viscoelastic properties by measuring the shear waves produced by a vibrating mechanical transducer. As an alternative to biopsy and to enable noninvasive visualization and quantification of stiffness, MRE has been used successfully to estimate the stage of hepatic fibrosis . RecentlTherefore, the purpose of this study was to evaluate the feasibility of transpelvic 3D MRE of the uterus and to assess the diagnostic performance of 3D MRE in predicting tumor aggressiveness, including histological subtype, tumor grade, FIGO stage, and myometrial invasion of EC.This retrospective study was approved by our institutional review board, and all patients provided informed consent. From August 2015 to January 2019, 82 consecutive patients with suspected uterine tumors underwent pelvic MRI and MRE scans. Among them, 22 patients who had histopathological confirmation of EC after surgery were selected. Seven patients were excluded because (1) the MRE examination failed (n = 1) due to obesity (thickness of subcutaneous fat was 3.75 cm), and the images could not be used for quantitative analysis; (2) they had a history of previous radiotherapy/chemotherapy (n = 2); and (3) their lesion had a maximum diameter of < 2 cm (n = 4). Finally, 15 patients with EC were enrolled in this cohort study. Figure b values (b = 0 and 800 s/mm2).MRI was performed on a 3.0T scanner  with 8-channel phased-array torso coils  for signal acquisition. MRE was performed with a pneumatic driver developed by Mayo Clinic . The driver was placed above the pelvis. Continuous acoustic vibrations at 60 Hz, which were transmitted from an active driver to the passive driver via a flexible vinyl tube, were used separately to produce propagating shear waves in the cervix. A test vibration was first applied to allow the patient to become familiar with the vibration. A free-breathing, multislice, EPI, 3D-MRE sequence was used. The acquisition parameters included repetition time = 1334 msec, echo time = 52 msec, slice thickness = 3 mm, interslice gap = 0 mm, number of slices = 20, FOV = 240 mm, acquisition matrix = 80 × 80, superior-inferior spatial saturation bands, and parallel imaging acceleration factor = 2. The total imaging time for MRE was approximately 80 s. Diffusion-weighted imaging (DWI) was performed using a respiratory-triggered single-shot spin echo echoplanar imaging sequence in the transverse plane before contrast-enhanced imaging, with 2 The MRE-acquired displacement fields were processed using a 3D direct inversion (DI) of the Helmholtz wave equation after applying the curl operator to calculate a stiffness map over the uterine volume. The reconstruction matrix was 256 × 256 × 20. The processing steps were applied automatically to generate quantitative images of tissue shear stiffness maps in units of kilopascals (kPa).In each case, the mean stiffness of the EC was calculated using a manually specified region of interest (ROI). The ROIs were drawn by two radiologists , both of whom were highly experienced in pelvic MRI with more than 5 years of experience. The ROIs excluded tumor edges, areas of significant wave interference and any other artifacts seen in the magnitude and wave images. The tumor ROI was drawn on the magnitude images with reference to conventional MR images. Then, the ROIs were copied to the stiffness map, which gave the stiffness values in kPa. The mean stiffness in kPa within the ROIs was reported. Apparent diffusion coefficient (ADC) maps were automatically generated from each DWI image by MRI system software .Patients were staged on the basis of the histopathological findings following surgical resection, according to the revised FIGO staging system (2009) . All oriU test was used to compare the stiffness value between different groups with abnormal distribution. To characterize the diagnostic accuracy of tumor stiffness in the assessment of tumor aggressiveness, receiver operating characteristic (ROC) curves were implemented. By maximizing the Youden index, we determined the optimal cutoff values and corresponding sensitivities and specificities for distinguishing between different groups. Statistical analysis was performed with SPSS 22.0 . p-values < 0.05 were considered statistically significant.Interobserver reproducibility for the ROI measurements of the two readers was assessed by using the interclass correlation coefficient . The independent-samples t-test was used to compare the stiffness value between different groups with a normal distribution. The Mann-Whitney n = 15) was 50.20 ± 9.03 years (range 35–65 years). Among these patients, 6  were premenopausal and 9  were postmenopausal. Patient characteristics are detailed in Table The mean patient age in the study sample n = 5 was 50.p = 0.136). The stiffness value of EC with ≥ 50 % myometrial invasion was significantly higher than that of EC with < 50 % myometrial invasion , but there were no significant differences in tumor size between the other subgroups . For DWI, the ADC value showed no significant differences between any subgroups.The categorizations of endometrial cancer with corresponding stiffness values are detailed in Table In addition, the interobserver variability of tumor stiffness was low, with intraclass correlation coefficients of 0.89 to 0.94 and a minimum detectable change of 0.01 to 0.2 kPa for the different tumor stiffness measurements.To our knowledge, this is the first study to use 3D MRE to assess the aggressiveness of EC. In our preliminary study, we demonstrated that preoperative tumor stiffness as measured by 3D MRE could predict tumor aggressiveness, including grade of differentiation, FIGO stage, and depth of myometrial invasion of EC, suggesting that this parameter may serve as a noninvasive imaging biomarker for preoperative risk stratification to guide surgical treatment and adjuvant therapy.In our series, we found that the stiffness value of EC with deep myometrial invasion was significantly higher than that of EC with superficial myometrial invasion, with a cutoff value of 3.04 kPa to distinguish EC with deep myometrial invasion from EC with superficial myometrial invasion. However, the role of stiffness in modulating the growth and progression of EC remains poorly defined. Previous studies have demonstrated that several factors may contribute to increased malignant stiffness, including collagen deposition in the extracellular matrix, high cellularity, abnormal perfusion, and increased interstitial fluid pressure from the altered vasculature , 23. CurEarly-stage EC shows a good prognosis, and the 5-y survival rate is reported to be more than 90 % in patients with stage Ia or Ib disease . HoweverTwo distinct types of EC based on histological and molecular characteristics have been described in a previous study, and type II EC is usually less differentiated than type I EC and is more prone to infiltration and metastasis , 32. OurDespite our promising results, our preliminary study does have several limitations. First, this was a retrospective study performed at a single institution, and the sample size was relatively small. Thus, our findings need to be reproduced in larger patient series with longer follow-up and evaluation of prognostic information to confirm the possible value of MRE as a preoperative biomarker in EC. Second, as a confounding factor of bias, menopausal status may influence our results. In our small cohort study, 40 % of the patients were premenopausal. A previous study showed that stiffness changed in the uterine corpus during the menstrual cycle, which was related to the anatomic and functional alteration of both the myometrium and the endometrium . Future In conclusion, preoperative tumor stiffness as measured by 3D MRE could predict tumor aggressiveness and may be a strong prognostic factor in EC. Preoperative 3D MRE as part of a multiparametric MR protocol may, thus, serve as a noninvasive imaging biomarker for diagnosis and appropriate therapeutic strategy determination for patients with EC.