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排序方式: 共有315条查询结果,搜索用时 31 毫秒
1.
Sophia X. Sui Lana J. Williams Kara L. Holloway-Kew Natalie K. Hyde Julie A. Pasco 《International journal of molecular sciences》2021,22(1)
Sarcopenia is the loss of skeletal muscle mass and function with advancing age. It involves both complex genetic and modifiable risk factors, such as lack of exercise, malnutrition and reduced neurological drive. Cognitive decline refers to diminished or impaired mental and/or intellectual functioning. Contracting skeletal muscle is a major source of neurotrophic factors, including brain-derived neurotrophic factor, which regulate synapses in the brain. Furthermore, skeletal muscle activity has important immune and redox effects that modify brain function and reduce muscle catabolism. The identification of common risk factors and underlying mechanisms for sarcopenia and cognition may allow the development of targeted interventions that slow or reverse sarcopenia and also certain forms of cognitive decline. However, the links between cognition and skeletal muscle have not been elucidated fully. This review provides a critical appraisal of the literature on the relationship between skeletal muscle health and cognition. The literature suggests that sarcopenia and cognitive decline share pathophysiological pathways. Ageing plays a role in both skeletal muscle deterioration and cognitive decline. Furthermore, lifestyle risk factors, such as physical inactivity, poor diet and smoking, are common to both disorders, so their potential role in the muscle–brain relationship warrants investigation. 相似文献
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1 放射性废物管理方面( 1 )应当建立一个国家级的废放射源管理战略。此战略应包括过去、现在和将来产生的所有放射性废物。此废物管理战略可以由国家指定的委员会来制订。该委员会可以包括来自主要废物的产生单位、废物管理机构和相应的审管部门的代表。此战略应当涵盖技术选择 (处理和处置 )和基础架构 (废物管理机构和基金 )。( 2 )放射性废物管理 ,包括废密封源管理。要求有专门的技术设施和特别训练的人员。为避免基础结构和人力资源重复设置 ,可以考虑单一的废物管理机构。该机构可设有区域性的分支机构 ,也可以设有专门的部门管理来… 相似文献
4.
F. Monfort A. Berkani G.E. Thompson K. Shimizu 《Surface & coatings technology》2007,201(21):8671-8676
The mechanism of coating growth during sparking anodizing of aluminium is probed by use of an electrolyte containing both silicate and phosphate ions, with subsequent determination of the locations of silicon and phosphorus species through the coating thickness. Importantly, the main alumina-based layer of the coating contains incorporated silicon and phosphorus species of differing distributions. Phosphorus species are primarily found in a region next to the metal, representing roughly about 30% of the layer thickness. Silicon species are located mainly above this region to the layer surface. New coating material is added in discreet amounts associated with breakdown events, which provide short-circuit paths through the layer. The growth processes within the discharge region result in separation of the silicate- and phosphate-derived species, which may relate to their different mobilities, dependent upon factors such as charge, size and bonding with other species. Further, silicon-rich material is deposited at the surface of the alumina-based layer, which is often encountered in spark anodizing in silicate electrolyte. 相似文献
5.
Bernhard Blümich Vladimir Anferov Sophia Anferova Martin Klein Radu Fechete 《大分子材料与工程》2003,288(4):312-317
A special unilateral NMR sensor has been designed for investigations of thin samples with a thickness of less than 1 mm and of surface effects of polymers. For use with the bar‐magnet NMR‐MOUSE®, the so‐called “crazy coil” is introduced with a low penetration depth. It is a flat meander coil etched on a printed circuit board with wiggles in the conductors. The design of the new coil and FEM simulations of the B 1 field are presented. Different applications are discussed by means of illustrative examples. They are the detection of surface damage in rubber samples, the swelling and drying of a latex membrane exposed to cyclohexane vapor mimicking a chemical sensor, and the drying of a thin sprayed adhesive layer.
6.
Initial stages of plasma electrolytic oxidation of titanium 总被引:1,自引:0,他引:1
T. H. Teh A. Berkani S. Mato P. Skeldon G. E. Thompson H. Habazaki K. Shimizu 《Corrosion Science》2003,45(12):2757-2768
The initial stages of oxide growth on titanium are examined in a recently developed commercial alkaline pyrophosphate/aluminate electrolyte of interest for plasma electrolytic oxidation of light metal alloys. Constant current anodizing was employed, with resultant films examined by scanning and transmission electron microscopies and Rutherford backscattering spectroscopy. The initial film is relatively uniform and composed of TiO2, with low concentrations of aluminium and phosphorus species incorporated from the electrolyte. With increase in voltage the film breaks down locally, and regions of original and modified film develop simultaneously, with the latter occupying more of the surface as the voltage rises. Porous regions due to dielectric breakdown also become increasingly evident. At 240 V, sparking commences, and the surface reveals extensive, relatively uniform porosity, with the coating now containing much enhanced concentrations of aluminium and phosphorus species compared with the coating at lower voltages. The films develop at low efficiency due to generation of oxygen. The oxygen is produced within the original film material and at sites of dielectric breakdown. The former type of film develops a two-layered morphology, with an outer layer of amorphous TiO2 and an inner layer with numerous fine and course cavities. The cavities are due to the generation of oxygen that may be associated with the formation of anatase in the inner layer. 相似文献
7.
We demonstrate a microfluidic continuous-flow protein separation process in which silica-coated superparamagnetic nanoparticles
interact preferentially with hemoglobin in a mixture with bovine serum albumin, and the resulting hemoglobin-nanoparticle
aggregates are recovered online using magnetophoresis. We present detailed modeling and analysis of this process yielding
quantitative estimates of the recovery of both proteins, validated by experiments. While several previous studies utilize
an average particle size in modeling magnetophoretic particle trajectories or process design, in this study we emphasize the
importance of accounting for particle size distributions in calculating particle recovery, and therefore in estimating separation
efficiency. We combine experimentally measured size distributions of protein-nanoparticle aggregates with simulations of particle
trajectories and provide a simple analytical method to calculate the efficiency of separation at various flow speeds, which
fully accounts for heterogeneity in particle sizes. Our method can potentially be used for affinity based biomolecular separations
at both analytical and preparative scales by exploiting well-established techniques to functionalize nanoparticle surfaces
with selective ligands. Further, the modeling methodology presented here may be applied to provide better estimates of particle
recovery in a broad range of magnetophoretic separation processes involving heterogeneity in particle sizes. 相似文献
8.
The study aims were, in a population of university students, staff, and faculty (n = 140), to: 1) determine the distribution of seven measures of mobile device use; 2) determine the distribution of musculoskeletal symptoms of the upper extremity, upper back and neck; and 3) assess the relationship between device use and symptoms. 137 of 140 participants (98%) reported using a mobile device. Most participants (84%) reported pain in at least one body part. Right hand pain was most common at the base of the thumb. Significant associations found included time spent internet browsing and pain in the base of the right thumb (odds ratio 2.21, 95% confidence interval 1.02–4.78), and total time spent using a mobile device and pain in the right shoulder (2.55, 1.25–5.21) and neck (2.72, 1.24–5.96). Although this research is preliminary, the observed associations, together with the rising use of these devices, raise concern for heavy users. 相似文献
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