Application of neural networks and finite element computation for multiscale simulation of bone remodeling

In this paper, a novel multiscale hierarchical model based on finite element analysis and neural network computation was developed to link mesoscopic and macroscopic scales to simulate the bone remodeling process. The finite element calculation is performed at the macroscopic level, and trained neural networks are employed as numerical devices for substituting the finite element computation needed for the mesoscale prediction. Based on a set of mesoscale simulations of representative volume elements of bones taken from different bone sites, a neural network is trained to approximate the responses at the meso level and transferred at the macro level.     

Effects of a plyometric training program with and without added load on jumping ability in basketball players

The purpose of this investigation was to examine the effect of a standard plyometric training protocol with or without added load in improving vertical jumping ability in male basketball players. Twenty-seven players were randomly assigned to 3 groups: a control group (no plyometric training), plyometric training group (PG), and loaded plyometric group (LPG, weighted vests 10-11% body mass). Before and after the 10-week training program, all the players were tested for the 5-jump test (5JT), the squat jump (SJ), and the countermovement jump (CMJ). The PG and LPG groups performed 2 and 3 training sessions per week, during the first 3 and the last 7 weeks, respectively. The results showed that SJ, CMJ, and 5JT were significantly improved only in the PG and LPG groups. The best effects for jumps were observed in LPG (p < 0.01), which showed significantly higher gains than the PG (p < 0.05). In conclusion, it appears that loads added to standard plyometric training program may result in greater vertical and horizontal-jump performances in basketball players.     

Reactive oxygen species, dietary restriction and neurotrophic factors in age-related loss of myenteric neurons

We have studied the mechanisms underlying nonpathological age-related neuronal cell death. Fifty per cent of neurons in the rat enteric nervous system are lost between 12 and 18 months of age in ad libitum (AL) fed rats. Caloric restriction (CR) protects almost entirely against this neuron loss. Using the ROS-sensitive dyes, dihydrorhodamine (DHR) and 2-[6-(4'-hydroxy)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (HPF) in vitro, we show that the onset of cell death is linked with elevated intraneuronal levels of reactive oxygen species (ROS). Treatment with the neurotrophic factors NT3 and GDNF enhances neuronal antioxidant defence in CR rats at 12-15 months and 24 months but not in adult or aged AL-fed animals. To examine the link between elevated ROS and neuronal cell death, we assessed apoptotic cell death following in vitro treatment with the redox-cycling drug, menadione. Menadione fails to increase apoptosis in 6-month neurons. However, in 12-15mAL fed rats, when age-related cell death begins, menadione induces a 7- to 15-fold increase in the proportion of apoptotic neurons. CR protects age-matched neurons against ROS-induced apoptosis. Treatment with neurotrophic factors, in particular GDNF, rescues neurons from menadione-induced cell death, but only in 12-15mCR animals. We hypothesize that CR enhances antioxidant defence through neurotrophic factor signalling, thereby reducing age-related increases in neuronal ROS levels and in ROS-induced cell death.     

The alpha-tubulin gene family in wheat (Triticum aestivum L.) and differential gene expression during cold acclimation.

The alpha-tubulins and beta-tubulins are the major constituents of microtubules, which have been recognized as important structural elements in cell growth and morphogenesis, and, recently, for their role in regulation and signal transduction. We have identified 15 full-length cDNAs for the members of the alpha-tubulin gene family in hexaploid bread wheat (Triticum aestivum L.). The genes were clustered into 5 homeologous groups of 3 genes. Representatives of the 5 homeologous groups were mapped to different chromosome arms, and the genome of origin was determined for each gene. Changes in mRNA levels were observed for the paralogous members of the gene family during cold acclimation. Three members of the family had initial decreases in mRNA levels in response to cold treatment, which were followed by increases, each with a different pattern of reinduction. One gene-family member showed increased mRNA for up to 14 d during cold acclimation and had decreased levels after 36 d of cold treatment; a fifth paralogous member of the gene family had slowly declining mRNA levels up to 36 d. Subtle differences in the level of gene expression among homeologs and large differences among paralogs were detected by comparing the relative abundance of wheat alpha-tubulin expressed sequence tags (ESTs) in public databases.     

Validity and Reliability of New Agility Test among Elite and Subelite under 14-Soccer Players

Background

Agility is a determinant component in soccer performance. This study aimed to evaluate the reliability and sensitivity of a “Modified Illinois change of direction test” (MICODT) in ninety-five U-14 soccer players.

Methods

A total of 95 U-14 soccer players (mean ± SD: age: 13.61±1.04 years; body mass: 30.52±4.54 kg; height: 1.57±0.1 m) from a professional and semi-professional soccer academy, participated to this study. Sixty of them took part in reliability analysis and thirty-two in sensitivity analysis.

Results

The intraclass correlation coefficient (ICC) that aims to assess relative reliability of the MICODT was of 0.99, and its standard error of measurement (SEM) for absolute reliability was <5% (1.24%). The MICODT’s capacity to detect change is “good”, it’s SEM (0.10 s) was ≤ SWC (0.33 s). The MICODT is significantly correlated to the Illinois change of direction speed test (ICODT) (r = 0.77; p<0.0001). The ICODT’s MDC₉₅ (0.64 s) was twice about the MICODT’s MDC₉₅ (0.28 s), indicating that MICODT presents better ability to detect true changes than ICODT. The MICODT provided good sensitivity since elite U-14 soccer players were better than non-elite one on MICODT (p = 0.005; d_z = 1.01 [large]). This was supported by an area under the ROC curve of 0.77 (CI 95%, 0.59 to 0.89, p<0.0008). The difference observed in these two groups in ICODT was not statistically significant (p = 0.14; d_z = 0.51 [small]), showing poor discriminant ability.

Conclusion

MICODT can be considered as more suitable protocol for assessing agility performance level than ICODT in U-14 soccer players.     

Dramatic increase in the Zembretta Yelkouan shearwater breeding population following ship rat eradication spurs interest in managing a 1500-year old invasion

The ship rat (Rattus rattus) was introduced 1,500 years ago to the Zembra Archipelago (Tunisia) and was eradicated in October–November 2009 on two of its islands, Zembretta and Zembrettina. This eradication was performed 2 years after the discovery of a small colony of Yelkouan shearwaters (Puffinus yelkouan), a species recently up-listed to the vulnerable IUCN extinction risk category. For 2 years before and 3 years after rat eradication, the Zembretta Yelkouan shearwater breeding colony was checked yearly at the end of the breeding season. The number of recorded breeding pairs reaching 176 and 145, respectively, increases of 10.4 and 8.5-fold two and 3 years after rat eradication. This experiment shows that eradication of an ancient introduced ship rat population has dramatically improved the Zembretta Yelkouan shearwater breeding population very quickly. This result suggests that managing even long-introduced populations might well be fruitful.