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901.
Amyotrophic lateral sclerosis (ALS) is a rapidly progressing disease, which is accompanied by degeneration of both the upper (cortical) and the lower (spinal and bulbar) motoneurons. Clinically it is primarily characterized by a continuously and systematically spreading of muscular paresis and atrophy. The discovery of many novel ALS genes advanced the genetics of ALS rapidly within the past few years. Beyond the well-established superoxide dismutase 1 (SOD1) gene, chromosome 9 open reading frame 72 (C9ORF72), which turned out to be the most frequent ALS gene in Caucasians, TAR DNA binding protein (TARDBP) and fused in sarcoma (FUS) were recently added to the list of ALS genes. In addition, several rare ALS genes have been identified, which are mostly of cell biological and functional interest. The rapidly growing number of known ALS genes as well as the broadened phenotypic variability has increased the complexity of genetic diagnosis and counseling of ALS patients.  相似文献   
902.
903.
There is evidence that copepods undertake vertical migrations in shallow waters off the north coast of Java. They aggregate at the surface of the sea at dawn and dusk but sink to deeper levels in the middle of the day. Chaetognaths feed on copepods and tend to occur in areas which are rich in their prey. They do not however follow them on vertical migrations during daylight.  相似文献   
904.
The thermophilic marine bacterium Rhodothermus marinus produces a modular family 10 xylanase (Xyn10A). It consists of two N-terminal family 4 carbohydrate binding modules (CBMs) followed by a domain of unknown function (D3), and a catalytic module (CM) flanked by a small fifth domain (D5) at its C-terminus. Several truncated mutants of the enzyme have been produced and characterised with respect to biochemical properties and stability. Multiple calcium binding sites are shown to be present in the two N-terminal CBMs and recent evidence suggests that the third domain of the enzyme also has the ability to bind the same metal ligand. The specific binding of Ca2+ was demonstrated to have a pronounced effect on thermostability as shown by differential scanning calorimetry and thermal inactivation studies. Furthermore, deletion mutants of the enzyme were less stable than the full-length enzyme suggesting that module interactions contributed to the stability of the enzyme. Finally, recent evidence indicates that the fifth domain of Xyn10A is a novel type of module mediating cell-attachment.  相似文献   
905.
The main objective of this work is the evaluation, by means of the finite element method (FEM) of the mechanical stability and long-term microstructural modifications in bone induced to three different kinds of fractures of the distal femur by three types of implants: the Condyle Plate, the less invasive stabilization system plate (LISS) and the distal femur nail (DFN). The displacement and the stress distributions both in bone and implants and the internal bone remodelling process after fracture and fixation are obtained and analysed by computational simulation. The main conclusions of this work are that distal femoral fractures can be treated correctly with the Condyle Plate, the LISS plate and the DFN. The stresses both in LISS and DFN implant are high especially around the screws. When respect to remodelling, the LISS produces an important resorption in the fractured region, while the other two implants do not strongly modify bone tissue microstructure.  相似文献   
906.
907.
Glaucoma drainage device (GDD) has the potential to eliminate hypotony but still suffers from poor flow control and fibrosis. The ideal shunt should change its hydraulic resistance to achieve the desired intraocular pressure (IOP). In this study, the characterisation of a preliminary design of a new GDD is presented. This is activated by means of a diaphragm, which is actuated by conducting polymers. The valve can be manufactured employing microelectromechanical system technology by soft lithography. The characterisation process is performed by numerical simulation using the finite element method, considering the coupling between the fluid and the structure (diaphragm) obtaining the hydraulic resistance for several positions of the diaphragm. To analyse the hydraulic system of the microvalve implanted in a human eye, an equivalent circuit model was used. The parameters of the equivalent circuit model were obtained from numerical simulation. The hydraulic resistance of the designed GDD varies in the range of 13.08–0.36 mmHg min/μl compared with 3.38–0.43 mmHg min/μl for the Ahmed valve. The maximum displacement of the diaphragm in the vertical direction is 18.9 μm, and the strain in the plane is 2%. The proposed preliminary design allows to control the IOP by varying the hydraulic resistance in a greater range than the existing passive valves, and the numerical simulation facilitates the characterisation and the improvement of the design before its construction, reducing time and costs.  相似文献   
908.
909.
This work displayed the force capabilities of the musculoskeletal system of the forefinger under external loading. Different states of normal and pathological fingers are studied. We evaluated the impact of losing musculo-tendon unit strength capacities in terms of maximal output fingertip force and tendon tensions distribution. A biomechanical model for a static force analysis is developed through anatomical and kinematic studies. An optimisation approach is then used to determine tendon tension distribution when performing an isometric task. Furthermore, pathological fingers with common cases of injured flexors and extensors are analysed. The method of simulation for forefinger abnormities is described. Furthermore, the simulation results are interpreted.  相似文献   
910.
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