Therapeutic drug monitoring (TDM) of antibiotics has been practiced for more than half a century, but it is still not widely applied for infected patients. It has a traditional focus on limiting toxicity of specific classes of antibiotics such as aminoglycosides and vancomycin. With more patients in critical care with higher levels of sickness severity and immunosuppression as well as an increasingly obese and ageing population, an increasing risk of suboptimal antibiotic exposure continues to escalate. As such, the value of TDM continues to expand, especially for beta-lactams which constitute the most frequently used antibiotic class. To date, the minimum inhibitory concentration (MIC) of infectious microbes rather than classification in terms of susceptible and resistant can be reported. In parallel, increasingly sophisticated TDM technology is becoming available ensuring that TDM is feasible and can deliver personalized antibiotic dosing schemes. There is an obvious need for extensive studies that will quantify the improvements in clinical outcome of individual TDM-guided dosing. We suggest that a broad diagnostic and medical investigation of the TDM arena, including market analyses and analytical technology assessment, is a current priority. Consensus studies and guidelines have helped to propose values for these PK/PD targets, specific for an antibiotic in combination with a clinical condition [The need for precise measurement of antimicrobial agents in the blood of patients to follow treatment success or failure was recognized early on . Traditiondition –8. By coondition ).Here, we succinctly review the current status of TDM in the field of antibiotic therapy. Despite the fact that significant progress has been made in various disciplines in the field of TDM, there still seems to be a restricted global implementation.The majority of drug dosing regimens has been defined in healthy adults at the time of drug development where there was no resistance to those drugs. The lack of variability in PK and patient characteristics in those initial studies is not a representative of the breadth of patients in whom these drugs will be used and the ultimate exposure levels of such patients. It is highly unlikely that this “one dose fits all” strategy will maximize antibiotic effectiveness in all patients. Unpredictable drug concentrations in plasma and other body compartments due to altered volume of distribution and clearance may result from factors as diverse as acute pathophysiology during critical care admission (such as sepsis and immuno-suppression), obesity , early aAs a consequence, a growing body of evidence links sub-therapeutic antibiotic concentrations with treatment failure. For example, the “Defining Antibiotic Levels in Intensive Care Unit (ICU) patients” (DALI) study showed that up to 70% of critically ill patients in the ICU did not meet the PK/PD targets defined for beta-lactams, and that those patients with the lowest exposures were more likely to have a negative treatment outcome  . Similarwww.eucast.org) and CLSI (www.clsi.org) websites for more detail). Thus, the dynamics of what the antibiotic does to the infectious bacteria in vivo has to be revised according to the MIC of the strain. EUCAST representatives suggest to integrate inherent experimental variability of MIC testing into the calculation of PK/PD targets by applying the following rules [The decreasing antibiotic susceptibility of pathogens may require higher antimicrobial dosing to achieve a therapeutic exposure that maximizes treatment success . Still, ng rules . First, ng rules . Not eveng rules .An increased body of knowledge provides evidence for benefits associated with PK/PD target attainment, including variations in the dosing schemes, in terms of lower mortality, clinical cure, reduced length of stay and lower toxicity, as shown for many antibiotics. For example, continuous infusion as opposed to short-term infusion can help to reach more effective PK/PD targets and improve efficacy in case of sepsis where mortality can be reduced up to 30% , 32. VanFew studies have evaluated the impact of active TDM per se on the clinical course of critical care patients in prospective randomized trials , except From a historical perspective, TDM has been adopted mostly to prevent adverse toxicity effects, mainly for glycopeptides and aminoglycosides. Apart from the assessment of trough concentrations, also the determination of peak concentrations was considered to be diagnostically and, hence, therapeutically important. TDM of trough concentrations still is strongly recommended for all patients using the aforementioned antibiotics , 50.However, TDM is now on a slow rise in broader use to ensure optimum antibiotic exposure, in particular to avoid under-dosing, with evidence existing for many antibiotic classes including beta-lactams, linezolid and daptomycin (see statements above). With regard to beta-lactams, the most commonly monitored drugs are piperacillin-tazobactam and meropenem, followed by ceftazidime . Data reThe most commonly used method for current TDM involves immunological assaying, mostly using closed systems and automated chains. These are used in commercial kits for ‘toxic’ antibiotics like vancomycin and aminoglycosides and are mostly appreciated for their rapidity. However, standardization and calibration of this type of testing is not always easy. Immunoassays are often adapted to open chemistry mainstream chains to lower the overall cost  by Olympus Chemistry Systems and the tests provided by Randox Laboratories ).The second most used technology is that of liquid chromatography (LC) which is often combined with mass spectrometry (LC-MS). LC-MS uses mostly locally developed assays and protocols, which provides a level of experimental flexibility that can be easily adapted to commonly applied antibiotics. LC-MS is a highly adaptable technology, and when internal standard molecular markers are available and the equipment and associated personnel are within financial reach, this is a good diagnostic choice. On the other hand, duration of MS technologies (24–96 h) may pose a significant obstacle to clinical use. Application of LC-MS requires the employment of an expert scientist which makes a 24-h service difficult. The technology is not available in all laboratories but mainly in metropolitan-based laboratories which often leads to delayed or prolonged time to result. Actually, various forms of point of care testing are currently being developed and prototypes are being experimented with. The use of biosensor technologies has been proposed, superficially explored and the first results are promising –54. In tIt is suggested that for clinical application of TDM, one or two TDM measurements should be made during the very first dosing interval of the antibiotic treatment, then updated as much as needed after 48 h or before, depending on the antibiotic. The data can then be compared with PK models for specific populations, now available in any one of various software solutions that estimate the dose to use . In pracOf additional interest is the previously already mentioned use of continuous infusion of antibiotics in the ICU , 59. TheTDM should be clearly positioned as an integral part of the antimicrobial stewardship program in hospitals given its pivotal role in antibiotic treatment optimization. This will enable better delivery of the right antibiotic dose for the right patient at the right moment and for the right duration. As such, it will help combat the challenges provided by the growing AMR problem. This personalized medicine perspective still requires improvement to fully satisfy antibiotic prescribers. It is urgent that the TAT of TDM be shortened significantly and that accessible point of care tests and rapid technology–based assays enter the TDM market. Also, here are many practical questions around the implementation of TDM. How to coordinate results coming from microbiology and clinical chemistry laboratories? Who will integrate the data and issue a therapeutic advice? Who will be adjusting antimicrobial therapy and along which guidelines? When these issues have been resolved, TDM should become an integral part of the standard testing portfolio of all self-respecting clinical microbiology laboratories.


In this paper, uniaxial compression tests were carried out for recycled aggregate concrete with water cement ratios of 0.38, 0.49, and 0.66 and replacement ratios of 0%, 25%, 50%, 75%, and 100%, respectively. The influence of the replacement ratio of recycled aggregate and water cement ratio on the strength, elastic modulus, and deformation characteristics of concrete was discussed. The results show that the replacement rate of recycled aggregate has a significant effect on the macro stress–strain behavior of concrete. In the case of a constant water cement ratio, the peak nominal stress first decreases and then increases with the increase of the replacement rate; while the water cement ratios equal 0.38, 0.49, and 0.66, the corresponding transition states are 25%, 50%, and 50% of the replacement rate, respectively. The deformation and failure is characterized by two stages: distributed damage and local failure. Combined with the statistical damage mechanics, the influence of the aggregate replacement rate on the damage evolution mechanism of recycled concrete on a mesoscopic scale was explored. Two mesoscopic damage modes, fracture and yield, are considered. Their cumulative evolutions are assumed to follow triangular probability distributions, which could be characterized by four parameters. The peak nominal stress state and the critical state are distinguished, and the latter is defined as a precursor to local failure. With the increase of the replacement rate of recycled aggregate, the inhomogeneous evolution of mesoscopic damage shows obvious regular change, which is consistent with the internal chemical and physical mechanism and macro nonlinear stress–strain behavior. In recent years, with the construction of new buildings and demolition of abandoned buildings, a large amount of construction waste has been generated in cities. The amount of construction waste is increasing rapidly year by year, which is more obvious in developing countries such as China and India . CurrentThe application of recycled aggregate has become a priority project in various countries, and recycled aggregate concrete (RAC) is widely regarded as a new channel for sustainable development of the construction industry . PreciseKapoor et al., GF Belén et al., Beltrán et al., and Xiao et al. respectively carried out the mechanical test of RAC under uniaxial compression with different replacement rates of recycled aggregate, and the full stress–strain curves of RAC were obtained. The results showed that, with the increase of the replacement rate, the compressive strength and elastic modulus of RAC show a gradually decreasing trend, and the peak strain increased monotonously. The corresponding stress–strain curves have similar shape characteristics in test ,16,17,18Owing to the limitation of test technology, the studies on mechanical properties of RAC in the literature are mostly focused on the experimental analysis of macro mechanical properties, while the studies on microscopic damage mechanism are scarce. Moreover, most of the constitutive relations established are macroscopic phenomenological, focusing on the empirical fitting of test data, and could not establish an effective relationship between microscopic damage mechanism and macroscopic nonlinear constitutive behavior. In fact, the deformation and failure of quasi brittle materials (such as concrete and rock) is essentially a microscopic to macroscopic trans-scale damage evolution process, involving the nucleation, initiation, and propagation of micro defects (micro cracks and micro holes). The macroscopic nonlinear stress–strain behavior is determined by the heterogeneity of microstructure and the nonlinear damage evolution on a micro scale. Meanwhile, damage localization is a common phenomenon for quasi-brittle solid that macroscopic ultimate failure is caused by damage evolution and accumulation. Localization behavior deepens the complexity of material deformation and failure and the difficulty of analysis. On the basis of the catastrophe theory, Bai et al. divided the deformation and failure of quasi brittle solids into two stages: distributed damage accumulation and local disaster . They poStatistical damage mechanics is developed from continuous damage mechanics and has gradually become a research hotspot in the field of damage mechanics. It provides an effective method for studying the meso damage mechanism of quasi-brittle materials such as concrete. These kinds of models abstract quasi-brittle materials into a complex system composed of countless meso-elements (micro bar or micro spring). By assuming that the characteristic parameters of the meso-elements obey some form of statistical distribution, such as Weibull and normal, the heterogeneity in the microstructure of material could be introduced. In this way, both the complicated physical details of damage process and the complicated calculation of statistical mechanics could be avoided. It can be used to build a bridge between the meso damage mechanism and the macroscopic nonlinear mechanical behavior of quasi-brittle materials. Considering that there are two fundamental damage modes (fracture and yield) in the microstructure of concrete, the statistical damage models of concrete under uniaxial and multiaxial loading were proposed by Chen et al. and Bai et al. ,32,33,34In the second chapter, the basic assumption of the statistical damage theory is introduced. It describes the mesoscopic damage mechanism and macroscopic nonlinear mechanical behavior of concrete under uniaxial compression in detail, as well as the statistical damage model of concrete under uniaxial compression. The basic situation of the experiment, including the experimental scheme with three water cement ratios and five replacement rates, is demonstrated in the third chapter. Then, in According to the theory of intrinsic mechanical properties exert mechanism ,32,33, tOwing to the existence of micro-cracks, micro-holes, and other micro-defects in the concrete matrix before the force is applied, the micro-cracks will further expand with the increase of deformation under the external load. At the same time, new micro-cracks will be generated in the weak parts of the specimen because of local tensile strain exceeding the limit, accompanied by acoustic emission phenomenon in microstructure, which is called the degradation effect. This effect is known as the physical basis of traditional damage mechanics.Along with the degradation effect, the strengthening effect may also occur in the microstructure. At the initial stress stage, the stress skeleton in the microstructure is not optimal. With the nucleation and penetration of micro-cracks, the weak parts in the microstructure will gradually withdraw from the stress state. Meanwhile, stress redistribution will occur in the microstructure, and the stress skeleton is further optimized and adjusted, resulting in the potential mechanical capacity of the material being further liberated to be able to withstand greater external loads (effective stress). When the effective stress skeleton is adjusted to the optimum, it indicates that the potential mechanical capability of materials is fully released. After that, the material will not be able to withstand greater effective stresses, leading to local catastrophes. It is worth noting that this effect is ignored by traditional damage mechanics.In conclusion, in the process of damage evolution of concrete materials, the deterioration phenomena such as the initiation and propagation of micro-cracks in microstructure are just external representations. Meanwhile, the reinforcement effect generated by further optimization and adjustment of the force skeleton  should be regarded as the internal motivation, which determines the whole course.Under uniaxial compression, the compression direction is denoted as the main direction, and the corresponding nominal stress, effective stress, and compressive strain are marked as During the loading process, owing to the Poisson effect, the concrete specimen will produce transverse tensile strain in directions 1 and 2. Micro-cracks will occur randomly at certain weak parts (such as the interface between aggregate and cement mortar) in the microstructure of concrete, when its tensile strain exceeds the limit ,34. The During the loading process from the initial to state C (O→A→B→C), the density of micro-cracks increases gradually; the effective stress skeleton in microstructure could be further optimized and adjusted by means of the initiation and propagation of micro-cracks. Thus, the material system can obtain greater bearing capacity to maintain the balance with each load increment state. The effective stress After state C, the force skeleton of the microstructure cannot be further optimized by means of micro-crack generation and propagation, which indicates the potential mechanical capacities of the material have been played to the limit, and then the specimen will enter a failure stage characterized by local catastrophe. Damage localization will appear, forming the local compression failure zone (CFZ). In the CFZ, the compression damage will further aggravate with the expansion of macroscopic longitudinal tensile cracks; at state D, the localized shear band will further occur, which finally leads to the failure. Meanwhile, the rest of the specimen will unload and remain a continuum ,36. At tVan Geel studied the damage localization of concrete under compression . On the The above analysis shows that the deformation and failure of concrete under uniaxial compression is essentially a continuous damage evolution process in three-dimensional space ,34. The As shown in ibutions ,33,34. FH is the fracture damage value corresponding to the critical state.The characteristic tensile strains corresponding to  follows ,34:(1)σ=S is defined as the energy absorption capacity, which represents the energy absorbed by concrete in the process of stress and deformation , the compressive strength of RAC-I and RAC-II decreases monotonously, and then shows an upward trend in the interval . In addition to the different inflexion point (R = 25%), the compressive strength of RAC-III also conforms to the law of decreasing first and then increasing. At R = 100%, the compressive strength of RAC-I, RAC-II, and RAC-III increases by 9.7%, 10.8%, and 11.8% compared with NAC (R = 0%), respectively.As shown in Degradation effect: old cement mortar is attached to the surface of recycled aggregate, ITZ of new and old cement slurry is a weak area of mechanical properties , and theStrengthening effect: the high porosity of recycled aggregate means RAC contains more water and plays an internal curing role, which makes the later hydration reaction more thorough . MeanwhiCompared with NAC, there are two types of ITZ in RAC, namely old aggregate and old mortar, as well as regenerated aggregate and new mortar, as shown in R is in the range of 0–50% (RAC-III: 0–25%), the degradation effect is dominant, and the strength of RAC decreases with the increase of the replacement rate, while R at the range of 50–100% (RAC-III: 75–100%) shows the opposite situation to the one above.In this experiment, when Experiment dates of uniaxial compression obtained by different scholars for test blocks with standard maintenance for 28 days are shown in εp is the peak strain corresponding to the nominal peak stress. −3 to −4.15 × 10−3, with an increased monotonically trend. For RAC-II, with R = 50% as the limit, the peak strain first increases from −1.94 × 10−3 to −3.28 × 10−3, and then decreases to −1.66 × 10−3. It can also be seen clearly that, when the peak strain of RAC-III is bounded by R = 25%, it first increases from −1.89 × 10−3 to −3.15 × 10−3 and then decreases to −2.55 × 10−3.E for RAC-I, RAC-II, and RAC-III with the replacement rate, respectively. It can be seen that the curve has obvious regularity. For RAC-I, E decreases by 51.3% from 17.96 GPa to 8.74 GPa, showing a trend of rapid decline first and then to level, with the inflection point at R = 50%. As for the change trends of E for RAC-II and RAC-III, they decrease first and then increase with the replacement rate. When the replacement rate is 100%, E of RAC-II increases by 17.7% from 22.3 GPa to 26.24 GPa, and E of RAC-III decreases from 26.2 GPa to 22.32 GPa with a 14.8% reduction.During the uniaxial compression test, the specimens will undergo several typical stages, each of them corresponding to different mechanical characteristics. On the basis of catastrophe theory, the quasi-brittle solid failure is divided into the distributed damage accumulation stage and local catastrophe stage by Bai et al. . They poNonlinear mechanical behavior of concrete is the macroscopic representation of meso-heterogeneous damage evolution, and the macroscopic stress–strain curve contains effective information of mesoscopic damage evolution process. On the basis of the statistical damage model, the influence of recycled aggregate replacement rate on the mesoscopic damage evolution of concrete under uniaxial compression is studied according to the experimental curve. The intrinsic relationship between the physical-chemical mechanism, the mesoscopic damage evolution mechanism, and the macroscopic nonlinear mechanical behavior is discussed. Referring to Chinese code , PoissonR = 50% (RAC-III: R = 25%) as the boundary, the envelope shapes of RAC-I, RAC-II, and RAC-III show obvious rules with the increase of the replacement rate.The nominal stress–strain curves fitted by the statistical damage model are presented in H), the specific shapes of triangular probability distributions corresponding to the mesoscopic damage evolution of yield and fracture could be determined, and the vivid physical pictures will be presented.According to the four characteristic parameters (R = 50% (RAC-III: R = 25%) as the boundary, they present a trend of linear increase and then linear decrease. As for RAC-I, with R = 50% as the boundary, −4 at R = 0% to 12.62 × 10−4 at R = 100%, as the critical state strain increases monotonously with the replacement rate. The yield damage pattern reflects the process of optimization and adjustment of the stress skeleton of concrete microstructure. Unfortunately, it cannot be measured effectively by the existing experimental techniques. In R of recycled aggregate on 2 between the predicted and fitted values of the parameters is also given in the figures.The change curves of yield damage related parameters, H of RAC-I, RAC-II, and RAC-III are shown in 2 between the predicted and fitted values is also given. With R = 50% (RAC-III: R = 25%) as the boundary, H shows a trend of linear increase and then linear decrease. The fracture damage pattern of concrete is associated with the density of micro-crack, and also closely related to the physical and chemical reactions in concrete. As mentioned above, recycled aggregate has both a degradation and strengthening effect on concrete. Taking RAC-II as an example, when R is in the interval , the degradation effect (more microdefects and the existence of the old ITZ) of recycled aggregate is dominant, manifesting the reduction of microstructure density and the deterioration of mechanical properties of concrete. With the increase of the replacement rate, H increases linearly from 0.231 to 0.353. When R is in the interval , the strengthening effect (the further hydration of old cement and the roughness of aggregate boundary) of recycled aggregate is dominant, manifesting the increase of microstructure density and the improvement of mechanical properties of concrete. With the increase of the replacement rate, H decreases linearly from 0.353 to 0.197.The change curves of fracture damage related parameter R = 100%. For RAC-II, with R = 50% as the bound, the evolution process is first delayed and then accelerated with the increase of the replacement rate. When R = 50%, the ductility reaches the maximum. RAC-III is similar to RAC-II, except that the threshold replacement rate is changed to R = 25%. When In DR of RAC-I, RAC-II, and RAC-III are shown in H corresponding to the critical state first increases and then decreases with the increase of the replacement rate, and reaches a maximum value of 0.366 at R = 50%. For RAC-II, with R = 50% as the boundary, the ductility of uniform damage stage increases first and then decreases, which leads to the result that the growth of micro-cracks is slowed down and then accelerated. H reaches its maximum of 0.353 at R = 50%. RAC-III is similar to RAC-II, except that the boundary value of R is changed to 25%. H reaches its maximum of 0.329 at R = 25%. It can be seen that, at the critical state, the micro-crack density still remains in a relatively small range. In this experiment, the replacement of recycled aggregate can improve the ductility of concrete. For concrete with a water cement ratio of 0.66, 0.49, and 0.38, the replacement rates corresponding to the maximum ductility are 100%, 50%, and 25%, respectively.The evolution curves of fracture damage variable S of RAC-I, RAC-II, and RAC-III with the replacement rate of recycled aggregate are shown in Sp and Scr are the energy absorbing capacities corresponding to the nominal peak stress state and the critical state, respectively. In previous studies, Sp was often used to characterize the energy absorption capacity of concrete before failure [Scr is proposed to characterize the energy absorption capacity of concrete before local failure. It can be seen that, for RAC-I and RAC-III, Sp and Scr are monotonically increasing with the increase of the replacement rate. For RAC-II, however, Sp and Scr show a trend of increasing first and then decreasing, and reached the peak value at R = 50%. Obviously, the replacement of recycled aggregate effectively improves the energy absorbing capacity of the material.The change curves of energy absorbing capacity  failure ,38. In tεcr to peak strain εp under different replacement rates. Their values range from 1.28 to 1.65, with an average of 1.47. σcr to peak stress σp under different replacement rates. Their values range from 0.74 to 0.91, with an average of 0.83. The water cement ratio and the replacement rate of recycled aggregate have no obvious effect on the above ratios. Xiao et al. [o et al.  proposedUniaxial compression tests of recycled concrete with three levels of water cement ratio  and five levels of recycled aggregate replacement rate  were conducted in this paper. The test results show that the nominal stress–strain full curves have similar shape features under the quasi-static loading. The change rules of compressive strength, elastic modulus, and peak strain of three kinds of concrete with recycled aggregate replacement rate were discussed. The mechanical properties of concrete are closely related to the composition of material microstructure and the internal physical and chemical reactions, which are jointly controlled by the strengthening and degradation effects of recycled aggregate.There are similar failure modes between RAC and NAC. Macro cracks begin to appear in the middle of the concrete block after the peak nominal stress, and then the obvious bulging zone is formed in this part. Continuing loading, the deformation in local bulging zone is further increased, but unloading occurs in other parts. Inclined crack will appear in the middle, which leads to the ultimate failure of the concrete block. Taking the state when local bulging happens as the critical state, the deformation of concrete is divided into the distributed damage stage and local failure stage.H, have obvious regularity. The meso damage evolution law reflected by the model is in good agreement with the internal chemical physical mechanism and the macro nonlinear stress–strain behavior. Distinguishing between the peak nominal stress state and the critical state, the average values of σcr/σp and εcr/εp are 0.83 and 1.47, respectively. It is suggested that the critical state be taken as the ultimate failure state of the constitutive model, which can fully consider the ductility in the distributed damage stage of material and avoid the size effect in the local failure stage.On the basis of the statistical damage model, the mesoscopic damage evolution law of RAC under different replacement rates is discussed quantitatively. It considers two meso damage modes, fracture and yield, which represent the initiation and propagation of micro-cracks and the optimization and adjustment of the stress skeleton of microstructure, respectively. Yield damage plays a key role in the whole process of deformation and failure. The results show that, with the increase of the replacement rate, four characteristic parameters, The mechanical properties of recycled concrete are affected by many factors, including mix proportion, source of recycled aggregate, replacement rate of aggregate, type of additive, age, test environment, strain rate, loading mode, and so on. Owing to the limitation of the length of this paper, only two factors, the water cement ratio and replacement rate, are considered. The influence of various factors on the macro and micro mechanical properties of recycled concrete will be further studied in combination with micro test technology.


The scientific work by Monod  and NoviTo date, industry is investing in the development of continuous production processes, because of their better volumetric productivity and hence lower equipment cost. Moreover, powerful methods have been developed for continuous medium preparation and product purification . Finally, a continuous process can be run for an extended period and thus results in a more desired, ideally time invariant, and reproducible product quality. In future, more continuous bioprocesses will be used to produce pharmaceuticals, since the American Food and Drug Administration recently approved drugs produced by continuous cultivation  with a particular focus on closed feed-back loop control using PAT. Typical examples are the turbidostat (cell density controlled), nutristat (nutrient concentration controlled), and among others, the pH-auxostat, where the substrate consumption changes the pH and thus triggers a pH changing substrate feed. In general, the cells cultured under these conditions are growing at almost maximum specific growth rate (μmax). Other interesting applications of continuous cultivation are changestats, where the dilution rate is continuously increased (accelerostats or A-stats), decreased (deceleration-stats or De-stats), or kept constant with a continuous change of another parameter . A large potential of producing secondary metabolites and products is the retentostat, where all biomass is retained in a bioreactor and where the specific growth rate is practically zero.The goal of this electronic article collection is to give an overview on recent scientific advances in continuous cultivation. In their review article, Adamberg et al. applied the above described changestat approach to assess the adaptation of a human gut microbiota in A-stats and D-stats. The influence of the dilution rate (D) was tested either starting with steady-states at D = 0.05 h−1 or D = 0.2 h−1 and increasing or decreasing the dilution rate to D = 0.05 h−1 or D = 0.2 h−1, respectively. Interestingly, the detected population distribution was consistent and confirmed the fact that in continuous cultivation the Monod constant (Ks) plays a decisive role in the population dynamics. Finally, this finding is important to enable an industrial cultivation of multi-strain probiotics and fecal transplantation mixtures.Barbera et al. describe the powerful approach of the chemostat cultivation to determine the necessary growth kinetics of the diazotrophic cyanobacterium Anabaena PCC7122 t model growth. The traditional batch approach was not appropriate, since along with the increase of the cell density, the average illumination is reduced and thus the metabolism is significantly affected. However, using small photobioreactors operated in a continuous mode, Barbera et al. were able to determine μmax and the half saturation constant for nitrogen (KN). They also could show that the specific maintenance rate was influenced by the medium composition and the illumination intensity supplied to the culture.Velu et al. investigated the potential of continuous outdoor cultures of the cyanobacterium Tolypothrix sp. by experimentally simulating the remediation of waste carbon dioxide (flue gas) and metal containing ash dam water from coal-fired power plants that are typically found in Australia. The entire process was economically feasible when the remediation was combined with the production of food-grade phycocyanin alone or in combination with biomass production as biofertilizer using either vertical or raceway suspension cultures.Clostridium autoethanogenum to generate biofuel and chemicals from CO2 and H2 was assessed by Heffernan et al. using chemostat cultivations. The authors combined their experimental approach with a metabolic flux model and were thus able to optimize the conversion efficiency by supplementing the culture with CO. In future, this data set may be used to favor biosynthesis of a particular cell product.The potential of the acetogenic bacterium Kopp, Slouka et al. propose to evaluate the dynamic feeding and selection that takes place in the recently developed segregostat and also give an overview on existing online monitoring tools for Escherichia coli.Many physiological studies have shown that recombinant plasmids containing antibiotic resistance as selection marker may get lost without antibiotic selection, which renders this expression system failure prone and more expensive because of the need for continuous addition of antibiotics. However, new techniques, like CRISPR/CAS9 and related methods guarantee a better genetic stability. Nevertheless, the natural selection of better adapted cells  in Escherichia coli in a two-stage chemostat using glycerol as a carbon source in the first stage and glycerol and lactose as inducers replacing IPTG in the second stage. The space-time-yield could be increased by a factor of 100 in comparison to a single-stage chemostat cultivation.In industry, the product synthesis is frequently done in fed-batch cultivations in a phase separated manner, meaning the biomass formation is followed by the induction of genes of interest during the production phase. This set-up can also be established in a continuous manner by using two-stage chemostats. Hanik et al. reported the production of tailor-made medium chain length poly (mcl-PHA) in two-stage, parallel chemostat cultivations. In the first stage (one bioreactor) Pseudomonas putida was grown and in the second chemostat stage consisting of 4 parallel chemostats the substrates for mcl-PHA production  were added. This approach allowed a faster identification of the design window for tailor-made PHA production.This continuous two-stage cultivation technique has also been implemented in research studies. Tapia et al. developed a two-stage chemostat cultivation technique in order to assess the viral dynamics and the interaction of defective interfering particles (DIPs) of influenza A virus with the canine cell line MDCK.SU2. The design of a mathematical model enabled the interpretation of the observed cell and viral oscillations in the second chemostat stage. It was concluded that continuous two-stage cultivations could be efficiently used to produce DIPs.MZ has drafted the manuscript and submitted in final form. TE, CH, and AN have revised the manuscript draft. 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.


Epi-Aids, or epidemiologic assistance investigations, are an important mechanism through which Centers for Disease Control and Prevention supports public health organizations. We described the characteristics of Epi-Aids conducted during 2005–2014 and summarized the publication outcome of Epi-Aid related scientific information products.We performed a descriptive analysis of all Epi-Aids conducted during January 1, 2005–December 31, 2014; investigations were categorized by health topic and geographic distribution. We highlighted investigations of substantial public health importance, e.g., multistate investigations and investigations of epidemics and pandemics. We identified the Epi-Aid publication outcome by searching PubMed for Epi-Aid related publications, which included Morbidity and Mortality Weekly Reports (MMWRs) and peer-reviewed publications with an Epidemic Intelligence Service Officer (EISO) as a coauthor. We calculated publication timeliness and categorized publications by journal impact factor.During the study period, 698 EISOs and their collaborators participated in 807 Epi-Aids throughout the United States and globally. Approximately 81 Epi-Aids were conducted annually ; 632 (78.3%) were infectious disease-related; 161 (20.0%) were international, supporting 68 countries. As of June 2015, EISOs, in collaboration with partners, published 131 MMWRs and 280 scientific manuscripts on the basis of the 807 Epi-Aids conducted during the study period; 394 (48.8%) Epi-Aids resulted in publications in 80 peer-reviewed journals.EISOs play a critical role in conducting Epi-Aids, which require qualified field epidemiologists who can rapidly respond to requests for assistance during public health emergencies. Publications based on Epi-Aids share new knowledge with the scientific community, furthering progress of public health science and practice. The Epidemic Intelligence Service (EIS) is a 2-year combined training and service fellowship program for health professionals interested in the practice of applied epidemiology ,2. The EEISOs learn epidemiology and public health practice through service; a fundamental experiential training for EISOs is providing short-term epidemiologic assistance for investigations of serious and urgent public health problems. This assistance is provided in response to formal requests from state, local, federal, and international organizations, and foreign ministries of health (Epi-Aids) . The goaTo request an Epi-Aid, public health agencies or organizations formally invite CDC to assist in the investigations . In certEpi-Aids are an important mechanism through which CDC carries out its mission-critical activity of supporting public health departments and other organizations. Although a previous publication summarized Epi-Aids during 1945–2005 , publicaWe performed a descriptive analysis of all Epi-Aid investigations conducted during January 1, 2005–December 31, 2014, by assessing data captured in the EIS Epi-Aid database and Epi-1 request documents. To assess differences in health topics investigated, we categorized the nature of the investigation into infectious disease, chronic disease, environmental health-related, injury-related, and other. The geographic distribution of Epi-Aids was categorized into domestic  or international . We highlighted investigations of substantial public health importance, e.g., multistate investigations and investigations of epidemics and pandemics.http://www.ncbi.nlm.nih.gov/pubmed), and searched for Epi-Aid related publications on the basis of data from the EIS Epi-Aid database and Epi-1 request documents. The search included MMWRs and peer-reviewed publications with an EISO as a coauthor. When necessary, a Google Scholar®  or Scopus®  search was conducted to identify the number of citations. To assess the dissemination timeliness of these publications, we calculated the number of days from the Epi-Aid initiation date to publication date; if the exact publication date was unavailable, the 15th day of the specified month was used. MMWRs and manuscripts on the basis of Epi-Aids conducted during the study period and published before June 2015 were included in our study; if both the electronic publication and print dates were available, the earlier date was chosen.To identify the Epi-Aid publication outcome, we accessed the National Library of Medicine’s database of biomedical literature , obtained from the 2014 Journal Citation Reports® . (JCR) . An impaDuring January 1, 2005–December 31, 2014, a total of 698 EISOs and their collaborators participated in 807 Epi-Aid investigations throughout the United States and globally. Approximately 81 Epi-Aids were conducted each year  with the highest annual number of Epi-Aids being requested during 2009 and the lowest during 2007 . On averAmong the total 807 Epi-Aid investigations, 632 (78.3%) were infectious disease-related . The disSalmonella Saintpaul infections associated with consumption of raw produce, which infected > 1,440 persons in the United States [Acanthamoeba keratitis associated with use of a contact lens solution [Escherichia coli O157:H7 infection associated with consumption of prepackaged spinach. In 2012, four Epi-Aid investigations were conducted by 12 EISOs in response to a fungal meningitis outbreak among patients who received contaminated steroid injections [Salmonella infections  associated with consumption of raw tomatoes eaten in restaurants in the United States [Samonella outbreaks involved 21 states and resulted in the identification of 459 culture-confirmed cases of salmonellosis.The majority of Epi-Aids in our study were conducted in the United States (80.0%); 87 (10.8%) Epi-Aids were multistate or nationwide investigations; and 37 were conducted in U.S. territories. During 2008, the percentage of domestic investigations (88.4%) was higher than other years. In 2008, seven Epi-Aids were requested and 14 EISOs participated in response to a multistate outbreak of d States . In 2007solution , a multijections –21. Durijections –24; alsod States . These SA total of 161 (20.0%) Epi-Aids were international and provided support to 68 countries . Epi-AidMMWRs and 828 days  for manuscripts. A total of 110 (39%) manuscripts were published within two years of Epi-Aid initiation, and 110 (84%) MMWRs were published within one year of Epi-Aid initiation.As of June 2015, CDC EISOs, in collaboration with external public health partners, have published 411 scientific information products, including 131 MMWRs and 280 scientific manuscripts on the basis of Epi-Aid investigations conducted during January 1, 2005–December 31, 2014 . Among 8EISOs collaborated with public health authorities in the inviting jurisdictions to publish findings from Epi-Aid investigations in a total of 80 peer-reviewed medical, public health, and state medical journals. The majority of manuscripts (55%) were published in a journal with an IF of 1–5; a total of 31 (11%) manuscripts were published in journals with IFs from 1 to < 2; and 49 (18%) manuscripts were published in journals with IFs from ≥ 2 to 3. Nineteen (7%) manuscripts were published in a journal with an IF of > 20. Manuscripts on the basis of Epi-Aids were most commonly published in Clinical Infectious Diseases (11.4%), Emerging Infectious Diseases (8.2%), and Infection Control and Hospital Epidemiology (7.5%).Among the Epi-Aid investigations published, EISOs served as first author on 240 (86%) manuscripts, and as coauthors on 40 (14%) manuscripts; the manuscripts published during the study period were cited 6,536 times, approximately 23 times per manuscript , with 252 (90%) manuscripts cited at least once. The manuscript most cited was about an investigation of patterns of abuse among unintentional pharmaceutical overdose fatalities and was cited 450 times since its publication in 2008 . The majEISOs are a vital element at the frontline of public health, conducting epidemiologic investigations, research, and surveillance-related activities, both domestically and internationally . EISOs aThrough the Epi-Aid mechanism, EISOs provide technical expertise for rapid response to outbreaks and other public health emergencies; streamline access to CDC subject matter expertise, laboratory, and other resources; and strengthen epidemiologic capacity in the jurisdiction requesting assistance. Epi-Aids also offer instrumental learning opportunities to EISOs regarding application of epidemiologic methods and public health interventions. In addition, during public health emergencies  pandemic, and Ebola epidemic), CDC’s Emergency Operations Center (EOC), the command center for monitoring and coordinating response activities to public health threats in the United States and internationally, is activated. The EOC serves as a centralized component that provides EISOs and CDC staff the resources needed to effectively carry out public health response. For example, during the EOC activation in response to the 2009 influenza A (pH1N1) pandemic, > 3,300 CDC staff, including EISOs, supported this international response .The majority of Epi-Aids in our study were conducted in response to infectious disease-related threats. Infectious disease remains a primary concern to public health agencies with health departments spending approximately $58 million/year preventing infectious diseases . To servDuring the past 60 years, the geographic scope of Epi-Aid investigations has broadened and an increase in support to international health authorities has been observed. During 2005–2014, the number of international investigations increased to approximately 20%, compared with only 11% during 1946–2005 . This inAlthough Epi-Aids are both effective and beneficial, these investigations do not represent the full response of CDC or the EIS program. CDC staff and EISOs are often deployed outside the Epi-Aid mechanism to assist in outbreak investigations. For example, as of November 2015, approximately 2,000 CDC staff and EISOs participated in > 2,500 field deployments to assist with Ebola response efforts that included surveillance, contact tracing, data management, laboratory testing, and health education across the United States and Africa (CDC administrative data). In addition, hundreds of CDC staff were stationed at the EOC to provide logistics, staffing, communication, analytics, management, and other Ebola response support functions.Besides demonstrating expertise in epidemiologic investigations, EISOs are expected to attain prescribed competencies in scientific communications. After completing an Epi-Aid investigation, EISOs submit a report to the pertinent public health authority that clearly presents findings and recommendations to guide decisions, policies, and public health action. As part of their training, EISOs are encouraged to collaborate with field partners to publish Epi-Aid investigation results. During our study period, EISOs published > 400 scientific information products on the basis of Epi-Aids, and approximately half of the Epi-Aids resulted in ≥ 1 publication. Although the primary objective of Epi-Aids is to prevent and control public health problems, the resultant publications share new knowledge, lessons learned, and recommendations with the scientific community, furthering progress of public health science, practice, and policy.Our study has certain limitations. First, because of the high level of scrutiny and extensive peer-review process required before publication, the analyses focused on MMWRs and manuscripts published in peer-reviewed journals. Our study did not include abstracts, which although cleared by CDC, are not peer-reviewed and are difficult to compare across different conferences. Second, our study might underestimate the number of publications, particularly for Epi-Aids conducted during 2014. Given that it can take months after journal acceptance for MMWRs and manuscripts to be published, certain Epi-Aids might not have been captured in the analyses or might have been missed if not clearly associated with an Epi-Aid or EISO coauthor. Third, we lacked information regarding the date of Epi-Aid completion, which would be a more accurate way to measure the time necessary for an EISO and collaborators to publish their work on the basis of Epi-Aids. Finally, our study included publications on the basis of Epi-Aids with EISOs as coauthors, which might underestimate the total number of publications available on the basis of Epi-Aids.The EIS program has served the United States and the world for > 60 years and will continue to play a critical role on behalf of CDC in supporting our public health partners in investigating public health concerns. Although Epi-Aids are only a part of work performed by EISOs, they represent a substantial contribution of epidemiologic assistance to the United States and international community. Collectively, Epi-Aids provide knowledge transfer and also offer EISOs an avenue for broader experience and training in epidemiologic methods, communications, and leadership. Because new public health problems emerge and the practice of applied epidemiology expands to new areas , EISO pa


FRP (Fiber Reinforced Polymer) Bar reinforced coral concrete beam is a new type of structural member that has been used more and more widely in marine engineering in recent years. In order to study and predict the flexural performance of CFRP reinforced coral concrete beams, the flexural rigidity, crack morphology and failure mode of concrete were studied in detail. The results show that under the condition of similar reinforcement ratio, the flexural rigidity of CFRP reinforced coral concrete beam is significantly lower than that of ordinary reinforced concrete beam. Increasing the cross-section reinforcement ratio within a certain range can increase the bending stiffness of the test beam or reduce the deflection, but the strength utilization rate of CFRP reinforcement is greatly reduced. The short-term bending stiffness of the CFRP reinforced coral concrete beam calculated by the existing standard formula is obviously higher. This paper proposes a modified formula for introducing the strain inhomogeneity coefficient ( Recently, coral concrete has been gradually used in the coastal area and islands for building construction due to its environment friendly feature. coral concrete with the use of coral reefs and other island reef deposits as aggregates and seawater instead of freshwater can greatly reduce the production and transportation costs. It is major composition, coral debris, can be easily found from the ocean. This new type of product therefore has a high economic value without damaging the natural environment. However, corrosion of reinforcing bars caused by the humidity and hot marine environment in the coastal area and the large amount of salt in coral debris cause the main durability problem of coral concrete ,2. FiberFRP reinforced concrete beams are characterized by large deflection, wide crack width and no obvious yield stage ,7,8,9. GIn order to understand the changing characteristics of the flexural performance of the test beam under different loads, accurately calculate and predict the flexural rigidity of the FRP bar-reinforced coral concrete beam, and establish a calculation model for the flexural stiffness, the flexural behavior, short-term stiffness and failure modes of CFRP reinforced coral concrete beams are studied in detail through full scale flexural tests.Six coral-concrete beams reinforced with fiber bars and two coral-concrete beams reinforced with steel were tested by four-point bending test. All test beams were designed according to existing fiber-reinforced concrete codes and were load-graded using force control. Coral concrete is a kind of lightweight aggregate concrete.The CFRP bars used in the tests were manufactured by Zhejiang Haining Anjie Composite Material Co., Ltd. . Their basic mechanical properties of shown in 2), the cover of the concrete is 25 mm, and the diameters of the longitudinal bars are 8 mm, 10 mm and 12 mm  with a load transducer . During the tests, the load is increased with 3 kN increment at each step. Each loading step is held for 5 min to ensure the instrumentation data is stabilized and the test data are recorded before the load was continuously to increase until the specimen is destroyed. In addition, the electronic crack monitor device  is used to measure the crack width of the concrete at the height of the longitudinal rebars, and the crack development height and crack development speed are measured and recorded. According to the test results, the bending performance of the test beams with different reinforcements is analyzed and compared. The development rate of deflection and crack width of the fiber reinforced test beam at different stages is different from that of the reinforced test beam. The fiber reinforcement test beam has problems such as large crack width, relative slippage of the reinforcement, and low utilization rate of the reinforcement. The stiffness changes under different load levels are worthy of further discussion.From the load-midspan deflection curve of the beams in 0/200 (l0 is the net span of the test beam) is allowed. When the midspan deflection of CFRP reinforced coral concrete beams reach l0/200 (10.5 mm), the load withstood by the CFRP reinforced coral concrete beam is only 23.5–38.5% of their ultimate bearing capacity. Under the same deflection, the steel reinforced coral concrete beams bear about 90% of their ultimate load. The test results are shown in Before concrete crack formed in tension zone, the increase of deflection is slower with the increase of load. After concrete cracking, the stiffness of CFRP reinforced coral concrete beams decreased rapidly, and the increase rate of deflection is obviously accelerated. Under the same load conditions, the deflection of CFRP reinforced coral concrete beams is obviously larger than that of reinforced coral concrete beams. The ultimate bearing capacity of C-8 test beams is not much different from that of steel reinforced coral concrete beams, but the mid-span deflection of CFRP reinforced coral concrete beams under the same load is about 3–4 times of that of latter. Within a certain range, increasing the reinforcement ratio of CFRP bars can significantly improve the flexural rigidity and reduce the deflection. The maximum deflection of C-10 and C-12 beams is 10.8% and 27% lower than that of C-8 beams, respectively. However, with the increase of CFRP reinforcement ratio, the low strength utilization of FRP bars becomes more serious. According to GB 50608-2010 , the maxFrom The development trend of load-strain curve of CFRP reinforced coral concrete beams is similar to that of ordinary reinforced concrete beams ,12,13,14l0/200 (10.5 mm), the strain of CFRP rebars under tension is about 30–41.9% of their ultimate strain, which indicates that the strength utilization ratio of CFRP bars is low. In addition, bond slip makes the strain of CFRP bar increase nonlinearly. Before the concrete cracks in the bottom tension zone, the strain values of steel reinforced coral concrete beams and CFRP reinforced coral concrete beams are similar because concrete withstand more tension stress. After cracking, the strain of CFRP bars increases sharply with the increase of load, which is obviously larger than that of steel bars under the same load value. The main reason is that the bond strength between CFRP bars and coral concrete is weaker than that of reinforcing bars. The relative slip between CFRP bars and coral concrete results in a greater redistribution of the tensile stress of CFRP bars. With the increase of reinforcement ratio of CFRP bars, the slope of load-strain curve increases, and the strain of CFRP bars decreases under the same load. When the midspan deflection of CFRP reinforced coral concrete beams reaches It should be noted that almost all CFRP bars reinforced coral concrete beams have slip between CFRP bars and coral concrete in varying degrees. The larger the load, the more obvious the slip. The relative slip curve of CFRP bars at the end of the test beams is shown in The failure modes of CFRP reinforced coral concrete beams are significantly different from those of steel reinforced coral concrete beams due to the different properties of reinforcement materials. The crack width and deflection of CFRP reinforced coral concrete beams are obviously larger than that of steel reinforced coral concrete beams. In addition, CFRP reinforced coral concrete beams have a large number of deep cracks along the longitudinal reinforcement direction. The slip between CFRP bars and coral concrete is also very serious. As shown in Due to the slip of CFRP bars has a significant effect on the deflection and stiffness calculation of test beams, the relatively weak bond between FRP bars and concrete makes the strain of CFRP bars more uniform than that of steel bars . When caThis section mainly compares some standard calculation formulas or calculation models with the test results and discusses the differences between different calculation formulas and cause analysis.Because there are few studies on the flexural behavior of FRP reinforced coral concrete, therefore, no corresponding formula for calculating flexural stiffness. There is some formula for FRP bar reinforced normal concrete can be referred to. They are from ACI 440.1R-15 , Zhu HoneI is the effective moment of inertia of FRP bar reinforced beam after cracking, crM is the moment when concrete cracks, aM is applied moment, gI is the moment of inertia of uncracked section, crI is the moment of inertia of uncracked section, The stiffness calculation formula of ACI 440.1R-15 is based on the code ACI 440.1R-06  and ACI fE is the elastic modulus of fiber, fA is effective cross-sectional area, ofh is the distance from the center of the longitudinal bar to the edge of the compression surface, Zhu  further The formula for deflection is as follows:From g et al.  effectivIt should be noted that a large number of experimental studies show that the load-deflection curve of FRP reinforced concrete beams under bending is not an ideal linear relation, but presents certain non-linear characteristics, especially in the stage of large load ,36,37. TAt present, there are big differences in the specifications or calculation models in different regions, and the factors considered in the formula are also different, which affect the accuracy of the calculation results of the fiber reinforced test beam. In addition, there are few studies on the stiffness of fiber reinforced coral concrete beams, and it is impossible to conduct a more comprehensive evaluation of its mechanical properties. Therefore, this article compares and analyzes the calculation results of different codes or models and proposes a stiffness calculation model for coral concrete beams on the basis of it.According to the existing calculation theory of flexural rigidity of concrete beams, the elastic modulus of materials and the crack characteristics of members have a significant impact on the flexural behavior and stiffness calculation of concrete beams. For reinforced concrete beams with cracks, the concrete segment between cracks actually bears part of the tension stress, and the tensile strain of the longitudinal bar in the pure bending sector is not uniform. Therefore, the determination of strain inhomogeneity coefficient of longitudinal tension bars between cracks is very important for the stiffness calculation. Previous studies have shown that the tensile strength of concrete is almost proportional to the bond strength. Most of the formulas are fully expressed about the important influence of concrete tensile strength and actual reinforcement ratio on the inhomogeneity coefficient of reinforced concrete beams, which is in accordance with the actual stress state. The inhomogeneity coefficient 010-2010  is as foObviously, the surface hardness and shear strength of steel bars are much better than that of FRP bars, and the shear failure of concrete is the main manifestation of interfacial slip. When the reinforcement ratio and the stress of steel bars are fixed, the inhomogeneity coefficient in Equation (8) decreases gradually with the increase of the tensile strength of concrete, which is in line with the actual situation. However, the bond-slip failure mechanism between FRP bars and concrete is more complex, and the bond performance between FRP bars and concrete is significantly different ,24,25,26Since all the FRP bars of the flexural members have non-uniform strain and all change in a close range, in this paper, forty eight test results of simply supported concrete beams with CFRP, BFRP and GFRP bars of different strengths are investigated based on the experimental results and the available reference ,46,47,48When developing the modified short-term stiffness calculation formula of FRP bars reinforced coral concrete beams, two key factors need to be considered. Firstly, the influence of material properties and surface conditions of FRP bars on flexural stiffness should be considered. The influence factors of bonding performance of different FRP bars to coral concrete should be introduced. Based on the experimental data and the bonding characteristic coefficients 0.9 here ,28,30.) Based on theoretical analysis and experimental data, the formulas for calculating the short-term flexural stiffness of CFRP reinforced coral concrete beams are presented as follows:Analyzed from the test results, the existing calculation model tends to overestimate the flexural rigidity of the fiber reinforced coral concrete beam and have certain accuracy only before and after the cracking of the test beams. However, as the load increases, the error becomes larger, and the design requirements for different load levels cannot be met. In the case of test beam failure, the errors of Zhu et al. , GB50608In fact, the calculation model of fiber reinforcement basically refers to the reinforced concrete specification, and does not consider the apparent condition of the reinforcement, the relative slippage of the reinforcement and the influence of the force characteristics at different stages on the components, so it is impossible to accurately calculate the components. From another point of view, if one does not understand the force changes of the components at different loads or at different stages, when the components are damaged during use, they cannot be accurately evaluated and repaired. Therefore, in-depth study of stiffness changes has far-reaching significance for the application of fiber reinforced concrete members.The calculation model proposed in this paper takes into account the force characteristics and influencing factors of the test beam at different stress stages and can predict the stiffness change and deflection deformation of the test beam under different loads. However, there is a lack of long-term mechanical performance test research on test beams and long-term load degradation and damage research in this field, so long-term stiffness prediction cannot be made. In the future work, Finite Element modelling  can be fThe flexural behavior of CFRP reinforced coral concrete beams is similar to that of steel reinforced concrete beams with good ductility, but the flexural stiffness of CFRP reinforced coral concrete beams is significantly lower than that of ordinary reinforced concrete beams. There is no obvious yield stage. After the cracking of concrete in tension zone, the stiffness of CFRP reinforced coral concrete beams decreases rapidly and the increase rate of deflection accelerates obviously.Increasing the reinforcement ratio of CFRP bars in a certain range can significantly improve the flexural rigidity and reduce the deflection of CFRP reinforced coral concrete beams. However, by increasing the reinforcement ratio to reduce the deflection of the test beam, it will reduce the utilization of the strength of the reinforcement.The bond performance between CFRP bars and coral concrete has a significant impact on the flexural performance and failure mode of CFRP bars. Most of the tested beams show obvious slip phenomenon under tension, which results in serious loss of flexural capacity of the flexural-shear section.The revised formula for strain inhomogeneity coefficient of CFRP bars in coral concrete beams proposed in this paper has higher accuracy.A new short-term stiffness formula of CFRP reinforced coral concrete beams is developed, which considering the low elastic modulus of FRP bars, the stress-strain characteristics of coral concrete and the bond performance. The relative slip coefficient is taken as 0.9, and the surface condition coefficient is 0.9. The calculated results are close to the experimental values.


Leuconostoc mesenteroides and Leuconostoc carnosum in the CN and SL frankfurters to Lactobacillus sakei/curvatus in the SL + SDA frankfurters. Thus, SL + SDA extends the retail shelf life of VP frankfurters by delaying total LAB growth and selecting for lactobacilli with a milder cured meat spoilage potential than leuconostocs, particularly under refrigeration.This study evaluated microbial growth in commercial frankfurters formulated with 1.8% sodium lactate (SL) singly or combined with 0.25% sodium diacetate (SDA), vacuum-packaged (VP) and stored at 4 °C and 12 °C. Standard frankfurters without SDA, containing 0.15% SL, served as controls (CN). Lactic acid bacteria (LAB) were the exclusive spoilers in all treatments at both storage temperatures. However, compared to the CN and SL treatments, SL + SDA delayed growth of LAB by an average of 5.1 and 3.1 log units, and 3.0 and 2.0 log units, respectively, after 30 and 60 days at 4 °C. On day 90, the SL + SDA frankfurters were unspoiled whereas the SL and CN frankfurters had spoiled on day 60 and day 30 to 60, respectively. At 12 °C, LAB growth was similar in all treatments after day 15, but strong defects developed in the CN and SL frankfurters only. Differential spoilage patterns were associated with a major reversal of the LAB biota from gas- and slime-producing  Feasible hygienic measures adopted during peeling, slicing and packaging of ready-to-eat (RTE) cooked cured meat products in commercial meat processing plants cannot guarantee complete avoidance of post-process contamination with various spoilage microorganisms ,2. CertaListeria monocytogenes contamination and growth in cold-stored VP or MAP frankfurters, sliced ham and other cooked cured meat products [During the last two decades, there has been an increasing use of combinations of organic acid salts, mainly sodium lactate (SL) or potassium lactate (PL) with sodium acetate (SA) or sodium diacetate (SDA), for controlling post-thermal products ,11,12,13products ,15. Becaproducts ,17,18,19products ,15. Seveproducts ,12.Carnobacterium spp. and certain Weissella or Leuconostoc spp., are more acid-sensitive, particularly to acetate, than the Lactobacillus sakei/curvatus group in vitro [Published studies that specifically address selective effects of lactates, acetates and other organic acid salts during storage of commercial RTE cooked cured meat products are scarce and lack comparative identification data regarding the main LAB species prevailing naturally within treatments ,19. Addiin vitro ,18,22,23In summary, intrinsic selective pressure effects of lactate and acetate salts on the growth dynamics of LAB in cooked meats remain largely unexplored despite the great progress in mapping the meat spoilage ecology overall by culture-dependent molecular identification tools and next generation sequencing approaches in recent years ,24,25,26w/w commercial product) SL, or 1.8% SL plus 0.25% SA, showed that SL + SA selected for Lb. sakei/curvatus strains with a mild spoilage potential, whereas the SL frankfurters spoiled more offensively due to high prevalence of Leuconostoc spp. that formed excessive in-package gas and ropy slime during storage at 4 °C and mainly at 12 °C [Lb. sakei/curvatus strains [Meanwhile, the need to conduct factory-specific studies to evaluate whether lactate and acetate salts may alter the LAB ecology in ways to delay, modify or reduce spoilage defects of cooked cured meat products was first pointed out in Greece by Samelis and Georgiadou . A laterat 12 °C . However strains . Therefow/w commercial product; Purac Inc. Lincolnshire, IL, USA) were used for treating 100 kg of pork skin, accounting for 0.15% pure SL already in the basic batter; thus, 0.15% SL was subtracted from the SL added to treatments below. Further details on the frankfurter recipe (% composition) were not provided because they were considered a confidential ”know-how” proprietary to the company. However, necessary precautions were taken during preparation of the experimental batters: (i) the production manager guaranteed that the standard frankfurter formula did not contain other antimicrobials, except common cured meat ingredients, sodium chloride, dextrose, powdered milk, starch, spices, nitrites, phosphates, Na-erythrobate, Na-glutamate and Na-ascorbate; (ii) all curing ingredients were added to the cutter in our presence; (iii) the desired SL and SDA concentrations were weighed and added to the frankfurter batters by the production manager under our close supervision.Frankfurters  were prepared in a local industrial meat processing plant  from pork meat and fat under standard commercial manufacturing conditions. The basic (standard) frankfurter formula contained 60% pork meat. Emulsified collagen comprised 11% of the final batter. For collagen emulsification, 2.27 kg of SL  and 1.8% SL plus 0.25% SDA . Standard frankfurters that contained 0.15% pure SL, manufactured without SDA and/or additional SL, served as controls (CN). Preparation of the CN samples was preceded followed by the preparation of the SL and SL + SDA samples to avoid cross-contamination of the batters and washing the cutter bowl between treatments. Following cooking, cooling, overnight storage at 4 °C and removal of the product casings, the peeled frankfurters of each treatment were vacuum packaged  in the plant, transported to our microbiology laboratory in insulated polystyrene iceboxes, and distributed in two cooling incubators , at 4.0 ± 0.1 °C and 12.0 ± 0.1 °C. Two independent frankfurter experimental trials, processed on different production days, were studied. For each experimental trial, two random VP frankfurter sample packs of each treatment were analyzed microbiologically and for pH and overall appearance on days 0, 7, 15, 30, 60, and 90 of storage. Additionally, two random, freshly-VP frankfurter samples per treatment were analyzed for moisture, fat, protein and salt contents in the industrial plant’s laboratory, where the treatments were also compared organoleptically, as described below.Briefly, the basic frankfurter batter was prepared and divided in 150-kg portions, which were mixed separately in the cutter to incorporate the salts. Treatments included addition of 1.8% SL (3% of the aforementioned 60% w/v) buffered peptone water (BPW) , and homogenized in a stomacher  for 1 min at low speed and 1 min at high speed at room temperature. Serial decimal dilutions in 0.1% BPW were prepared and 1 mL or 0.1 mL samples of the appropriate dilutions were poured or spread, in duplicate, on total and selective agar plates. All samples were analyzed for total spoilage microbiota enumerated on tryptone soy agar with 0.6% yeast extract (TSAYE) (Lab M), incubated at 30 °C for 72 h, and for total LAB enumerated on de Man, Rogosa & Sharpe (MRS) agar (Lab M), incubated at 25 °C for 72 h. Anaerobic incubation of the MRS plates was avoided to facilitate growth of all spoilage LAB types at 25 °C and the comparison with the total mesophilic (TSAYE) bacterial counts at 30 °C. Additionally, all frankfurter treatments were analyzed on days 0, 15, 30 and 90 of storage for the following microbiota expected to be subdominant or absent: enterococci on kanamycin aesculin azide agar (Lab M), incubated at 37 °C for 48 h; total staphylococci on Baird-Parker agar base (Lab M) with egg yolk tellurite , incubated at 37 °C for 48 h; total enterobacteria in violet red bile glucose agar , overlayed with 5 mL of melted (45 °C) same medium and incubated at 37 °C for 24 h; pseudomonad-like and other psychrotrophic gram-negative bacteria on Pseudomonas agar base (Lab M) with cephalothin-fucidin-cetrimide , incubated at 25 °C for 48 h; sulfite-reducing clostridia in 50-mL tubes containing 20 mL of melted sulfite-polymyxin-sulfadiazine agar , inoculated with 10 mL from the first dilution , cooled rapidly in ice-water, overlayed with 2 mL of sterile paraffin oil to exclude oxygen, and incubated at 37 °C for 24 h; and, yeasts on rose bengal chloramphenicol agar (Merck), incubated at 25 °C for 5 days. The microbial quantification methods and rapid confirmatory tests of the colonies grown on the above selective media were conducted according to the procedures described by Samelis et al. [Frankfurter samples (25 g) were transferred aseptically to 225 mL of 0.1%  equipped with a glass electrode was used for the measurement. The moisture, fat, protein and salt contents of the frankfurter samples were determined before storage (day 0), according to the AOAC official methods .No formal sensory panel testing with scale score sheets was conducted for the purposes of this study. However, the frankfurter treatments  of each production trial were evaluated comparatively by five experienced members of the industrial personnel, who judged whether addition of SL and SL + SDA in the batter might have affected the appearance, odor-flavor and taste of the fresh (day-0) frankfurters, compared to the CN frankfurters. For taste evaluation, the peeled frankfurters were immersed in an 80 °C water-containing cooking jar for 5 min, cooled, tested and the judgments of the industrial panelists were recorded and compared. Next, during storage, all VP frankfurter samples were checked for accumulation of milky exudates, gas and/or slime in-package and development of off-odors, ropiness and/or discoloration at, or soon after, pack opening in our laboratory.Potential compositional differences in the dominant spoilage LAB and other non-LAB contaminating biota between treatments were evaluated by the biochemical characterization of 240 representative isolates from the final frankfurter samples after 90 days of VP storage at 4 °C and 12 °C; when the products were either terminally spoiled or still acceptable for human consumption, depending on treatment. An equal number of 120 representative colonies were collected from each of the primary enumeration agar media for total bacteria  and LAB , respectively. Collection of the 120 isolates was done by picking ten colonies from one highest dilution TSAYE or MRS agar plate of one VP frankfurter sample for each treatment and experimental trial. Although the colony selection process was random, attention was paid to include all macroscopically different colony types, as analogously as possible to their visual occurrence, within the 10 isolates picked from each agar plate. By the above isolation procedure, 120 colonies  were collected from each storage temperature, or otherwise, 80 colonies in total  were collected from each of the CN, SL and SL + SDA frankfurter treatments.2O2 solution (Merck) onto the cell biomass [All isolates were grown in MRS broth at 25 °C, checked for purity by streaking on MRS agar, stored in MRS broth with 20% glycerol (Merck) at −30 °C. Fresh MRS agar cultures of all isolates were tested for Gram reaction by the 3% KOH method and catalase formation by dropping a 3% H biomass . Only th biomass ,40,41,42n = 4). The microbiological data were converted to log10 units and along with the pH data were subjected to one-way analysis of variance using the Statgraphics Plus for Windows v. 5.2  software. Means were separated by the Least Significance Difference (LSD) test at the 95% confidence level (p < 0.05) for determining differences in each frankfurter treatment with storage time. The same software was then used to find significant frankfurter treatment  effects in correlation with the storage temperature effects and LAB growth-enumeration media (TSAYE and MRS) effects on each sampling day.Two frankfurter production runs  were performed by analyzing two individual VP frankfurter samples on each sampling day per trial (p > 0.05) irrespective of organic acid salt treatment. Conversely, significant differences were noted in the initial pH between the SL + SDA and the CN and SL frankfurter treatments (p < 0.05) compared to the other two treatments, in agreement with the pH drop of similar pilot-plant frankfurter trials produced in the US previously [The mean moisture, fat, protein and salt contents of the frankfurters after peeling (day-0 of storage) were 59.4 ± 1.0 %, 17.9 ± 0.9%, 11.4 ± 0.4% and 2.3 ± 0.2%, respectively, and were similar  in the populations (log CFU/g) of total mesophilic bacteria (3.1 ± 0.4), LAB (2.6 ± 0.7), staphylococci (2.4 ± 0.4), enterobacteria (1.7 ± 0.4) and aerobic gram-negative bacteria (2.3 ± 0.3) were noted between frankfurter treatments before storage. Additionally, all frankfurter samples harbored less than 2.0 log CFU/g of enterococci, yeasts, and pathogenic staphylococci. Sulfite-reducing clostridia were absent/g (data not shown).No significant differences (p < 0.05) progressive growth in all VP frankfurter samples, and hence, sooner or later depending on the acid salt treatment, exceeded 6 log CFU/g during storage at 4 °C or 12 °C (p > 0.05) to the total bacterial populations grown on TSAYE at 30 °C .p < 0.05) in all frankfurter samples stored at 12 °C than 4 °C, irrespective of acid salt treatment and enumeration agar medium (p < 0.05) since they were greater in the order: CN > SL > SL + SDA (p < 0.05) growth of LAB by an average of 5.1 and 3.1 log units, and 3.0 and 2.0 log units, respectively, after 30 and 60 days of storage at 4 °C (p < 0.05), whereas the respective LAB populations in CN frankfurters were more than 10-fold higher (Growth of LAB was faster (r medium . HoweverSL + SDA . In spec at 4 °C . After 9d higher . Similard higher .p < 0.05) than at 4 °C, while again were similar on MRS ; in contrast, no pH decreases (p > 0.05) were noted in the SL + SDA samples stored at 4 °C  < SL  < CN  at 4 °C. Sensory defects developed much faster and were stronger during frankfurter storage at 12 °C. However, package swelling and excessive in-package ropy slime developed from day 15 to 30 in the CN and SL treatments only. In contrast, the SL + SDA sample packages stored at 12 °C either became ‘loose’ after the firmness of the packaging film with the frankfurter links was lost  or remained firm without visible spoilage defects throughout storage at 12 °C . Moreover, the SL + SDA frankfurter samples of the experimental trial 1 started accumulating small amounts of an in-package sticky slime rather than a watery ropy slime formed in the spoiled CN and SL samples after day 30. Conversely, the SL + SDA frankfurter samples of the experimental trial 2 were characterized by an unpleasant malty smell only after 30 days at 12 °C. Overall, the differences in pH drop , total LLb. sakei/curvatus group  genera [Lb. sakei/curvatus isolates fermented ribose, but none fermented mannitol, raffinose, sorbitol and xylose  and A3 , to include the atypical isolates of two intermediate Lb. sakei/curvatus biotypes, respectively  biotype-A3 [Latilactobacillus (Lb.) curvatus is clearly distinct at the genomic species level from Latilactobacillus (Lb.) sakei [Lb. curvatus subsp. melibiosus” was rejected as a later synonym of Lb. sakei subsp. carnosus [Lb. sakei subsp. carnosus from Lb. sakei subsp. sakei is not possible by biochemical criteria and thus requires molecular identification tools [Lb. sakei subspecies are biochemically intermixed [Lb. sakei [Lb. sakei and Lb. curvatus isolates from Greek cooked or fermented meat products, particularly as regards their variable fermentation reactions with L-arabinose, cellobiose, lactose, maltose, sucrose and trehalose [Lb. sakei and group B of Lb. curvatus into several additional biotypes of high phenotypic homogeneity without genotypic justification.All 240 isolates were LAB grouped and identified at the species level, according to their biochemical profiles presented in us group , which c) genera . All 153d xylose , four ofd xylose . The larelibiose . Group Aectively . Atypicas et al. ,46 and ls et al. . Atypicaotype-A3  also occotype-A3 . To date.) sakei  after thcarnosus . Discrimon tools ,49. Actutermixed  within ttermixed . Moreoverehalose ,37,40,41Leuconostoc or Weissella group of strains (Leuconostoc mesenteroides subsp. mesenteroides isolates (group E), followed by weaker gas-producing Leuconostoc carnosum (group F) isolates which were intermixed as regards their ability to form slime from sucrose. The remaining gas-producing isolates were slime-negative Lc. pseudomenteroides or Weissella paramesenteroides (group G), two species that also are biochemically intermixed [The second most frequent type of spoilage LAB  was the obligatory heterofermentative, arginine-negative  strains . All of  strains . Most oftermixed  and thustermixed ,50.Lb. sakei/curvatus and Leuconostoc/arginine-negative Weissella groups comprised the vast majority (96.2%) of the frankfurter isolates at spoilage  and Lb. sakei (subgroup A1) isolates, as well as, of the subdominant W. paramesnteroides (group G) isolates, irrespective of organic acid salt treatment (Lc. carnosum (group F) was ca. 5-fold higher from the frankfurter samples stored at 4 °C than 12 °C, whereas the isolation frequency of Lc. mesenteroides (group E) was ca. 4-fold higher from the frankfurter samples stored at 12 °C than 4 °C  frankfurter samples, all except one of the atypical ”Lb. curvatus/melibiosus” isolates (subgroup A3) were isolated from thermally abused (12 °C) frankfurter samples. No Lb. plantarum (group D) or Lactobacillus sp. (group C) isolate was found at 4 °C  of storage [ storage ,40,53,54Unlike the storage temperature, the two primary growth media (TSAYE vs. MRS) did not affect the isolation frequency of each LAB group of species .Lb. sakei/curvatus group of isolates was strongly enhanced  from the SL + SDA frankfurters was approximately 5-fold and 3-fold lower compared to the SL and CN frankfurters. Additionally, the isolation frequency of Lc. carnosum (group F) from the SL + SDA frankfurters was 5.5-fold and 3.5-fold lower compared to its isolation frequencies from the SL and CN frankfurters, respectively  were predominant, or at least numerous, in the SL + SDA frankfurter samples of the exp. trial 1, Lb. curvatus isolates (group B) dominated over Lb. sakei in the corresponding samples of the exp. trial 2  may reflect seasonal variations in the LAB species composition of the natural contaminating biota persisting in the industrial meat plant environment. Another variation may be due to the usage of high-pH pork which is preferred technologically for the manufacture of emulsion-type sausages because of its higher water holding capacity compared to normal-pH pork. A recent microbial study by Charmpi et al. [Lb. curvatus was more manifest in high-pH pork. Accordingly, the natural contamination and selective prevalence of Lb. curvatus may readily increase in frankfurter processing lines or under a constantly high pH (>6.0) on frankfurters formulated with SDA during refrigerated (mainly) or thermal abuse conditions of storage  and Lb. curvatus from Greek frankfurters and other cured cooked or fermented meat products [As regards the in-package sticky slime that occurred in the SL + SDA frankfurters of the first trial only, where in vitro , unlike products ,37,40,41products ,54, mostproducts . Overallproducts ,53. TherLc. mesenteroides and Lc. carnosum in the SL frankfurters of this study  pork sausage manufactured with PL and SA, whereas the removal of lactate and acetate from the product formulation resulted in higher numbers of non-LAB spoilers, mainly Brochothrix and Pseudomonas [The results of this industrial frankfurter study are in general agreement with the findings of Benson et al. , who firmb. nov. . Strainsudomonas .Lb. sakei subsp. carnosus, Lc. carnosum, Lc. gelidum and carnobacteria strains to prevail in Northern European meat products and plants [Potential selective effects to the benefit of predominant lactobacilli, and likely associated with addition of PL  in the formulation of Belgian sliced cooked meat products, were recently noted by Geeraerts et al. ,30. In sd plants ,28,29,30d plants ,40,56.Lb. sakei/curvatus in the industrial frankfurters should be considered when applying commercial meat bioprotective LAB cultures which, apart from Lb. sakei strains, may contain acetate-sensitive Carnobacterium spp. strains [Carnobacterium fraction to grow in cooked meat products formulated with SDA. Many studies have so far contributed to the development and application of effective cultures for meat biopreservation [Finally, the strong effects exerted by SDA on delaying LAB growth and selecting for  strains . Based oervation ,57,58,59ervation , while nLb. sakei/curvatus strains with the mildest possible in situ spoilage potential, unable to cause ropiness, on frankfurters and other cooked meat products formulated with the most effective lactate-diacetate blends. This intelligent biotechnological approach would effectively combine natural preservative (abiotic) factors in the product core with novel bioprotective LAB culture/s on the product surface, relying on their strong in situ synergistic competitive exclusion effects to increase shelf-life and safety of frankfurters and other processed meat products.In conclusion, 0.25% SDA combined with 1.8% pure SL  extended the retail shelf life of industrial VP frankfurters by two months under refrigeration, compared to the standard frankfurters manufactured without SL or SDA. Hence, effective management of the spoilage LAB species communities in frankfurters and other processed meat and poultry products may be achieved through selective pressure effects exerted by lactate  and acetate  combinations at optimal concentrations. Based on this study, further research is required (i) for optimizing the inclusion of SDA at levels lower than 0.25% to lessen texture and odor/taste defects sensed in the present SL + SDA frankfurters, too; (ii) for checking and optimizing the efficacy of existing commercial bioprotective cultures and for designing new bioprotective cultures for the meat processing industry. A feasible option that seems promising is to apply antagonistic


CPEB1 gene, in POI patients. However, the deleted region also includes other plausible genes, and thus the contribution of CPEB1 to POI is uncertain. The present study aimed to determine the relationship between CPEB1 deletion and POI in a Chinese cohort.Premature ovarian insufficiency (POI), which is characterized by early menopause before the age of 40 years, affects approximately 1–5% of women. Cytoplasmic polyadenylation element binding protein 1 (CPEB1) is a post-transcriptional regulatory protein that is highly expressed in germ cells and promotes oocytes maturation, and several studies have found microdeletions of chromosome 15q25.2, which contains the CPEB1 was performed to detect the CPEB1 deletion in 323 patients with POI and in 300 healthy controls. Subsequent qPCR with primers for each exon of CPEB1 was performed to precisely localize the deletion locus.Quantitative real-time polymerase chain reaction (qPCR) with primers for exon 4 and exon 11 of CPEB1 gene.One patient with primary amenorrhea was found to carry a heterozygous deletion of exons 8–12 of the CPEB1 deletions in POI patients using a simple qPCR method, and we show that CPEB1 deletion is not a common cause for POI in a Chinese cohort.Our study is the first to search for  Premature ovarian insufficiency (POI) is characterized by cessation of menstruation before 40 years of age combined with a serum level of follicle stimulating hormone (FSH) above 25 IU/L . ApproxiSTAG3, SYCE1, MSH5, GDF9, NOBOX, and FSHR. However, only a minority of the mutations have been verified through functional assays [The etiology of POI is heterogeneous, including chromosome abnormalities, gene mutations, autoimmune diseases, and iatrogenic factors; however, most cases are idiopathic. Genetic disorders account for 20–25% of POI cases, and chromosomal abnormalities explain 10–15% . Mutatiol assays .SYCP1 and SYCP3 – that are responsible for synaptonemal complex formation and homologous chromosome recombination [Cpeb1-knockout mice show atrophic ovaries devoid of oocytes, mimicking the phenotype of human POI [CPEB1 heterozygous deletions occur in 0.33–2.9% of POI patients of Caucasian descent using array comparative genomic hybridization assay (CGH array) or quantitative multiplex PCR of short fluorescent fragments techniques  has been found to regulate the translation of essential genes – such as bination . Cpeb1-kuman POI . PreviouThe inclusion criteria for POI were cessation of menstruation before 40 years of age and at least twice serum follicle stimulating hormone (FSH) concentrations exceeding 25 IU/L. In the present study, 123 patients with primary amenorrhea and 200 patients with secondary amenorrhea were recruited from Shandong Provincial Hospital Affiliated to Shandong University. Women with a history of pelvic surgery, chemotherapy, radiation therapy, or chromosome abnormalities were excluded. Three hundred women above 40 years of age with normal menorrhea and delivery history were recruited as controls. Written informed consents were obtained from all participants. The study was approved by the Institutional Review Board of Center for Reproductive Medicine, Shandong University.CPEB1 gene includes 12 exons, and qPCR with primers recognizing sequences in exon 4 and exon 11 was performed to screen for the gene deletion according to a previous CGH array with probes targeting exon 4 of CPEB1.Genomic DNA was extracted from the peripheral blood of all participants. The ACTB gene was used as the normalization control (Table -∆∆CT of the CPEB1 fragment compared to ACTB) by the corresponding ratio of the negative control DNA. This equation provided a theoretical dosage quotient value of 1.0 for two copies and a value of 0.5 for deletions. Three independent replicates were performed for each case, and independent samples t-tests were used to test for differences. We identified a CPEB1 deletion in one patient, and qPCR with primers for each exon of CPEB1 was performed to localize the deletion region.The 114 bp fragment targeting the ol Table . DNA samCPEB1 exon 4 and exon 11 in 323 patients and 300 controls, we found that the DNA dosage of exon 11 was reduced by half in one patient. Further qPCR for each exon of CPEB1 identified a heterozygous deletion of exons 8–12, which is required for folliculogenesis, is significantly reduced due to a shortened mRNA poly(A) tail, indicating a pivotal role for CPEB1 in oogenesis after birth [CPEB1 deficiency in humans might accelerate follicle atresia due to disrupted meiosis and oogenesis, thus resulting in ovarian failure at an earlier age, as is the case in POI.CPEB1 is an important post-transcriptional regulatory protein that binds to the CPE region of target mRNAs and promotes the polyadenylation and translation of the mRNAs , 8. CPEBertility . MoreoveCPEB1 is partially localized  in our cohort was low, indicating that CPEB1 microdeletion is not a common cause for POI in a Chinese population. Furthermore, we identified the specific deletion region of CPEB1 as being exons 8–12, which indicates the vital role of this region for the function of CPEB1.In previous studies using CGH array or SNP array analysis, a total of seven POI cases were found to carry a heterozygous deletion of chromosome 15q25.2, where The CPEB1 protein is composed of three regions – an amino-terminal portion with no obvious functional motifs, two RNA recognition motifs (RRMs), and a zinc finger motif . PreviouCPEB1, which could have missed microdeletions outside this region. Moreover, the functional study was not performed given the fact that the proteins regulated by CPEB1 are expressed in oocytes during meiosis or folliculogenesis, which cannot be cultured in vitro. Considering the limitation, animal models with CPEB1 deletion in exons 8–12 might be generated to further illustrate the pathogenic mechanism of such deficiency on mammalian oogenesis and ovarian function.The present study has some limitations that must be noted. The primary qPCR only tested exon 4 and exon 11 of CPEB1, which is required for synaptonemal complex formation and oogenesis, contributes to only a small minority of POI cases.Taken together, our results further illustrate that deficiency in