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BACKGROUND: The Topping-off technique, which combines lumbar fusion with the dynamic internal fixation system (Coflex), can not only reduce the pressure, but also protect the adjacent segments. There is no relevant mechanical analysis performed on the rationality of the application of Topping-off technique to young patients with the need for fusion on the lumbosacral region and adjacent degenerated segments. OBJECTIVE: To establish a finite element model of Topping-off surgery on the lumbosacral junction and to analyze the biomechanical changes of the adjacent segments and the range of motion trend of the lumbar spine. METHODS: A healthy young male volunteer with no previous history of low back pain or congenital malformations was randomly selected for thin-slice CT scanning after signed the informed consent. The image information was imported into the computer and the whole lumbar spine model as the healthy group model was established by analyzing the image informatlon through Mimics, Geomagic Studio 12.0, HyperMesh and Abaqus successively. After verifying the effectiveness of the model, the moderate degeneration model of intervertebral disc was established by changing the material properties of L4-S1 discs on the basis of the healthy model, and the fusion model and Topping-off model were respectively established on the basis of the degeneration model. After applying 400 N compressive load and 10 N•m momentum to the four groups of models, the variation trends of range of motion from L2 to L5 and the stress changes of L4/L5 intervertebral disc, nucleus pulposus and facet joints were calculated respectively. RESULTS AND CONCLUSION: (1) Compared with the degeneration model, the lumbar range of motion of Topping-off model and fusion model decreased, and the Topping-off model decreased more significantly than the fusion model. (2) The range of motion of fusion model L4-L5 increased significantly and the range of motion of L2/L3 and L3/L4 segments did not change significantly. Compared with the degeneration model, the L4-L5 range of motion of Topping-off model decreased, and range of motion of the L2/L3 and L3/L4 levels increased to some extent in the flexion and extension positions. (3) Compared with the degeneration model, the stress on the disc, nucleus pulposus and facet joint of the fusion model L4-L5 increased in four positions of flexion, extension, rotation and bending, while the fiber stress on the Topping-off model decraased significantly in all four positions. (4) These results suggest that Topping-off technology can not only reduca the stress on the upper adjacent degenerative intervertebral disc, nucleus pulposus and facet joints, but also reduce the hyperactivity of the adjacent segments and increase the range of motion of other upper segments, thereby compensating the lumbar spine mobility and delaying the degeneration of upper adjacent segments. [ABSTRACT FROM AUTHOR]

The Mullins effect during uniaxial compression tests, together with its reversibility, of ethylene-vinyl acetate copolymer (EVA)/nitrile-butadiene rubber (NBR)/zinc dimethacrylate (ZDMA) thermoplastic vulcanizates (TPVs) were investigated systematically. The experimental results indicated that the Mullins effect could be observed during the cyclic uniaxial compression tests and was accompanied with stress softening, residual deformation accumulation and hysteresis. The reversibility of the Mullins effect showed a temperature-dependent feature and was enhanced with increasing temperature. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus, a commensal and a pathogenic bacterium, causes a wide variety of diseases in humans and animals with a high impact on public health and the livestock industry. The risk of zoonotic transmission to humans highlights the need to understand the molecular ecology of S. aureus in foods. In this study, we obtained 25 S. aureus isolates from 39 crayfish samples in Hubei, China. PCR was applied for detection of presence of virulence and methicillin resistance genes in the pathogen genome. The result revealed that all of the 25 S. aureus isolates harbored at least four virulence genes, and 64 % of them were positive for five or more virulence genes. The most predominant virulence genes were coa, α- HL and β- HL genes (100 %), followed by sea (68 %), fnbA (60 %), tsst- 1 (36 %), while none of the examined isolates presented positive for mecA gene conferring methicillin resistance. Subsequently, all of the isolates were assessed for phenotypic biofilm formation with the microtiter plate assay. The results showed 92 % isolates could produce biofilm with different forming capacity. Multilocus sequence typing divided the isolates into five sequence types (STs), three of which (ST1920, ST188 and ST398) were the same with the isolates from livestock and clinic in China. This study provides preliminary insights into the genetic diversity and virulence gene profiles of S. aureus from crayfish, suggesting that S. aureus isolates from crayfish is a potential hazard for consumers and deserves further attention. [ABSTRACT FROM AUTHOR]

Ligustri Lucidi Fructus (LLF) is the fruits of Ligustrum lucidum Ait. (Oleaceae). This review based on nearly 80 literary sources discusses the knowledge of chemistry and biological effects of this species. Several types of chemical constituents considered as the characteristic and active constituents from LLF were isolated including 40 triterpenoids, 48 iridoids, 10 flavones, 10 phenylethanoid glycosides and others. Various extracts and individual compounds derived from this species have been found to possess a variety of pharmacological effects, e.g. anti-tumour, hepatoprotective, immune regulating, antioxidative and anti-ageing effects, anti-inflammation and reducing hypercholesterolaemia effects and so on. The results of data analysis on the chemical, pharmacological characteristics of LLF support the view that this species has many therapeutic properties and indicate its potential as an effective herbal remedy. Finally, some suggestions for further research on chemical and pharmacological properties are given in this review. Theoretical basis was given for further exploiting and utilising LLF. [ABSTRACT FROM AUTHOR]

Background: Wild potato Solanum bulbocastanum is a rich source of genetic resistance against a variety of pathogens. It belongs to a taxonomic group of wild potato species sexually isolated from cultivated potato. Consistent with genetic isolation, previous studies suggested that the genome of S. bulbocastanum (B genome) is structurally distinct from that of cultivated potato (A genome). However, the genome architecture of the species remains largely uncharacterized. The current study employed Diversity Arrays Technology (DArT) to generate a linkage map for S. bulbocastanum and compare its genome architecture with those of potato and tomato. Results: Two S. bulbocastanum parental linkage maps comprising 458 and 138 DArT markers were constructed. The integrated map comprises 401 non-redundant markers distributed across 12 linkage groups for a total length of 645 cM. Sequencing and alignment of DArT clones to reference physical maps from tomato and cultivated potato allowed direct comparison of marker orders between species. A total of nine genomic segments informative in comparative genomic studies were identified. Seven genome rearrangements correspond to previously-reported structural changes that have occurred since the speciation of tomato and potato. We also identified two S. bulbocastanum genomic regions that differ from cultivated potato, suggesting possible chromosome divergence between Solanum A and B genomes. Conclusions: The linkage map developed here is the first medium density map of S. bulbocastanum and will assist mapping of agronomical genes and QTLs. The structural comparison with potato and tomato physical maps is the first genome wide comparison between Solanum A and B genomes and establishes a foundation for further investigation of B genome-specific structural chromosome rearrangements. [ABSTRACT FROM AUTHOR]