Surface damage in cystine, an amino acid dimer, induced by keV ions.

We have studied the interaction of an ion beam (17.6 keV F-) with cystine, a dimer formed by the binding of two cysteine residues. Cystine can be considered as an ideal prototype for the study of the relevance of the disulfide (-S-S-) chemical bond in biomolecules. For the sake of comparison, the amino acid cysteine has also been subjected to the same experimental conditions. Characterization of the samples by XPS and NEXAFS shows that both pristine cystine and pristine cysteine are found as a dipolar ion (zwitterion). Following irradiation, the dimer and the amino acid show a tendency to change from the dipole ion form to the normal uncharged form. The largest spectral modification was observed in the high resolution XPS spectra obtained at around the N 1s core level for the two biomolecules. The 2p sulfur edge spectra of cysteine and cystine were much less sensitive to radiation effects. We suggest that the disulfide bond (-S-S-) remains stable before and after irradiation, contributing to the larger radiation stability of cystine as compared to the amino acid cysteine.

How do geometry-related parameters influence the clinical performance of orthodontic mini-implants? A systematic review and meta-analysis.

The aim of this systematic review and meta-analysis was to investigate how parameters related to geometry influence the clinical performance of orthodontic mini-implants (MIs). Systematic searches were performed in electronic databases including MEDLINE, Scopus, Web of Science, Virtual Health Library, and Cochrane Library and reference lists up to March 2016. Eligibility criteria comprised clinical studies involving patients who received MIs for orthodontic anchorage, with data for categories of MI dimension, shape, and thread design and insertion site, and evaluated by assessment of primary and secondary stability. Study selection, data extraction, quality assessment, and a meta-analysis were carried out. Twenty-seven studies were included in the qualitative synthesis: five randomized, eight prospective, and 14 retrospective clinical studies. One study with a serious risk of bias was later excluded. Medium and short MIs (1.4-1.9mm diameter and 5-8mm length) presented the highest success rates (0.87, 95% CI 0.80-0.92). A maximum insertion torque of 13.28Ncm (standard error 0.34) was observed for tapered self-drilling MIs in the mandible, whereas cylindrical MIs in the maxilla presented a maximum removal torque of 10.01Ncm (standard error 0.17). Moderate evidence indicates that the clinical performance of MIs is influenced by implant geometry parameters and is also related to properties of the insertion site. However, further research is necessary to support these associations.

Comparison of the effects of two resistance training regimens on muscular and bone responses in premenopausal women.

SUMMARY: A 28-week resistance training with linear periodization was compared with an undulating model in 27 premenopausal women. In both groups, bone mineral density (BMD) was not changed but muscle strength increased, and there were changes in anthropometrical and muscle damage parameters, indicating that in this population, these models are similar concerning these variables. INTRODUCTION: This study seeks to compare the effects of resistance training with undulating versus linear periodization on BMD, muscle strength, anthropometrical variables, and muscle damage parameters in premenopausal women. METHODS: Twenty-seven females (39.6 +/- 0.41 years, mean +/- standard error), without osteopenia or osteoporosis and without calcium supplementation, were randomly assigned either to a linear periodization group (LPG, n = 14) or to an undulating periodization group (UPG, n = 13). The subjects were trained three times a week for 28 weeks. Lumbar spine and femoral neck BMDs were measured through dual-energy X-ray absorptiometry. Maximal and submaximal dynamic muscle strengths were measured through the 1-RM and 20-RM tests, respectively. Anthropometrical (body mass, skinfolds, and perimeters) and muscle damage parameters were assessed through serum creatine kinase (CK) and delayed-onset muscle soreness (DOMS). RESULTS: BMD remained unchanged in both groups, despite significant increases in maximal (LPG, 37-73%; UPG, 40-70%) and submaximal (LPG, 82-114%; UPG, 70-102%) muscle strength. The perimeter of the distal thigh was increased (about 1.7 cm) in both groups. CK and DOMS were greater in the first mesocycle than in the subsequent ones. After the 1st training session in each mesocycle, 24 and 48 h CK was increased as compared to pretraining values. CONCLUSIONS: The resistance training of 28 weeks increased muscle strength in both training groups with no difference in BMD or in the occurrence of muscle damage.

[Diaphanization: modifications of organ weight and volume]. / La diaphanisation: modifications du poids et du volume des organes.

The diaphanization of organs previously injected with coloured substances is an excellent auxiliary method of numerous morphological studies. The authors studied 52 organs, among 15 were taken from human beings and 37 from dogs, with the aim of knowing theirs weight and volume modifications after diaphanization. The organs were diaphanizated with several impregnations in 10% formaldehyde, perydrol, acetone and at least embedding in a mixture of methylsalicylate and benzyl benzoate by vacuum process. After each embedding, weight and volume of each organ were measured. The variations that the organs suffered were statistically considered, under a few aspects: 1-global organs' variations after each embedding 2-different organs' variations 3-comparison between human being and experimental animals. In all cases, the authors noticed a great decrease of weight and volume, especially after dehydration steps with acetone and clearing with the mixture of methylsalicylate and benzyl benzoate. We also didn't find any significant difference between human organs and those taken from dogs.