Equivalence of regression curves sharing common parameters

In clinical trials, the comparison of two different populations is a common problem. Nonlinear (parametric) regression models are commonly used to describe the relationship between covariates, such as concentration or dose, and a response variable in the two groups. In some situations, it is reasonable to assume some model parameters to be the same, for instance, the placebo effect or the maximum treatment effect. In this paper, we develop a (parametric) bootstrap test to establish the similarity of two regression curves sharing some common parameters. We show by theoretical arguments and by means of a simulation study that the new test controls its significance level and achieves a reasonable power. Moreover, it is demonstrated that under the assumption of common parameters, a considerably more powerful test can be constructed compared with the test that does not use this assumption. Finally, we illustrate the potential applications of the new methodology by a clinical trial example.     

THE RELEVANT USE OF THE TRADITIONAL TUNISIAN GAME ‘‘RAQASSA’’ FOR CARDIOVASCULAR STIMULATION IN SCHOOLCHILDREN

The aim of this study was to investigate the heart rate (HR) responses, the rate of perceived exertion (RPE), and the feeling during physical education schooling while performing traditional games activities compared to intermittent exercise. Nineteen pre-pubertal children randomly performed on different days two types of lessons (intermittent running mode vs. traditional Tunisian “Raqassa” game) lasting 12-min each. HR was continuously recorded during both lessons, while ratings of perceived exertion and Feeling values were recorded after the sessions. The mean HR value during the traditional game was significantly higher than during intermittent exercise (p<0.05). Conversely, the perceived exertion score was significantly higher after intermittent exercise than the traditional exercise game (p<0.05), showing that the higher cardiovascular strain of the game was perceived as “lighter” than the run. Simultaneously, the children''s Feeling was significantly higher after the traditional game than intermittent exercise (p<0.001), showing a higher satisfaction from playing with respect to running. Exercise based on the “Raqassa” traditional game could be used in pre-pubertal children as an alternative or as an additional method for suitable cardiovascular stimulation during physical education lessons with lower perceived exertion and better feeling compared to intermittent running.     

Mechanical properties of a mature biofilm from a wastewater system: from microscale to macroscale level

A fundamental understanding of biofilm mechanical stability is critical in order to describe detachment and develop biofouling control strategies. It is thus important to characterise the elastic deformation and flow behaviour of the biofilm under different modes of applied force. In this study, the mechanical properties of a mature wastewater biofilm were investigated with methods including macroscale compression and microscale indentation using atomic force microscopy (AFM). The mature biofilm was found to be mechanically isotropic at the macroscale level as its mechanical properties did not depend on the scales and modes of loading. However, the biofilm showed a tendency for mechanical inhomogeneity at the microscale level as indentation progressed deeper into the matrix. Moreover, it was observed that the adhesion force had a significant influence on the elastic properties of the biofilm at the surface, subjected to microscale tensile loading. These results are expected to inform a damage-based model for biofilm detachment.     

Biaxial mechanical properties of the inferior vena cava in C57BL/6 and CB-17 SCID/bg mice

Multiple murine models have proven useful in studying the natural history of neovessel development in the tissue engineering of vascular grafts. Nevertheless, to better understand longitudinal changes in the biomechanics of such neovessels, we must first quantify native tissue structure and properties. In this paper, we present the first biaxial mechanical data for, and nonlinear constitutive modeling of, &QJ;the inferior vena cava from two models used in tissue engineering: wild-type C57BL/6 and immunodeficient CB-17 SCID/bg mice. Results show that inferior vena cava from the latter are significantly stiffer in the circumferential direction, both materially (as assessed by a stored energy function) and structurally (as assessed by the compliance), despite a lower intramural content of fibrillar collagen and similar wall thickness. Quantifying the natural history of neovessel development in different hosts could lead to increased insight into the mechanisms by which cells fashion and maintain extracellular matrix in order to match best the host stiffness while ensuring sufficient vascular integrity.     

Antimicrobial resistance in Campylobacter: Susceptibility testing methods and resistance trends

Most Campylobacter infections are self-limiting but antimicrobial treatment (e.g., macrolides, fluoroquinolones) is necessary in severe or prolonged cases. Susceptibility testing continues to play a critical role in guiding therapy and epidemiological monitoring of resistance. The methods of choice for Campylobacter recommended by the Clinical and Laboratory Standards Institute (CLSI) are agar dilution and broth microdilution, while a disk diffusion method was recently standardized by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Macrolides, quinolones, and tetracyclines are among the common antimicrobials recommended for testing. Molecular determination of Campylobacter resistance via DNA sequencing or PCR-based methods has been performed. High levels of resistance to tetracycline and ciprofloxacin are frequently reported by many national surveillance programs, but resistance to erythromycin and gentamicin in Campylobacter jejuni remains low. Nonetheless, variations in susceptibility observed over time underscore the need for continued public health monitoring of Campylobacter resistance from humans, animals, and food.     

Natural genetic variation in male reproductive genes contributes to nontransitivity of sperm competitive ability in Drosophila melanogaster

Female Drosophila melanogaster frequently mate with multiple males, and the success of a given male depends not only on his genotype but also on the genotype of his competitor. Here, we assess how natural genetic variation affects male–male interactions for traits influencing pre‐ and postcopulatory sexual selection. Males from a set of 66 chromosome substitution lines were competed against each other in a ‘round‐robin’ design, and paternity was scored using bulk genotyping. We observed significant effects of the genotype of the first male to mate, the second male to mate and an interaction between the males for measures of male mating rate and sperm utilization. We also identified specific combinations of males who show nontransitive patterns of reproductive success and engage in ‘rock‐paper‐scissors’ games. We then tested for associations between 245 polymorphisms in 32 candidate male reproductive genes and male reproductive success. We identified eight polymorphisms in six reproductive genes that associate with male reproductive success independent of the competitor (experimentwise P < 0.05). We also identified four SNPs in four different genes where the relative reproductive success of the alternative alleles changes depending on the competing males' genetic background (experimentwise P < 0.05); two of these associations include premature stop codons. This may be the first study that identifies the genes contributing to nontransitivity among males and further highlights that ‘rock‐paper‐scissors’ games could be an important evolutionary force maintaining genetic variation in natural populations.     

湖北省实验动物设施环境控制中存在的问题

目的分析总结湖北省2012年度实验动物许可单位年检中环境设施的检测结果,找出问题,提出促进湖北省实验动物环境设施可靠运行的建议。方法各实验动物环境设施采用30%区域抽检方式,依据GB14925-2010《实验动物环境及设施》,进行环境指标检测。结果除气流速度、沉降菌最大平均浓度外,其他技术指标均存在不符合国家标准的情况。结论应针对实验动物设施管理加强培训,提高实验动物设施管理人员的管理水平,从而保证实验动物设施的正常运行。     

朱顶红新品种DUS测试数量性状筛选与分级

利用70个朱顶红品种对12个数量性状进行了筛选及分级研究,并对5个数量性状的测量部位进行了研究。结果表明:所有性状均满足DUS测试要求,性状2由于区分能力弱不适于作为DUS测试性状。12个数量性状可进行3~9个连续分布的分级。花茎从下往上逐渐变细,但不同品种变细程度略有差异,在测量花茎中部的最大宽度时要求严格测量花茎的1/2处;不同茎上各数量性状测量值略有差异,除花茎长度和花梗长度外的性状差异不显著;同一花茎不同花间数量性状差异较小;同品种的花外花被片长度、宽度不存在显著差异;种球大小对数量性状有显著影响。