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排序方式: 共有78条查询结果,搜索用时 859 毫秒
1.
Glycine N-methyltransferase (GNMT) regulates S-adenosylmethionine (SAMe), a methyl donor in methylation. Over-expressed SAMe may cause neurogenic capacity reduction and memory impairment. GNMT knockout mice (GNMT-KO) was applied as an experimental model to evaluate its effect on neurons. In this study, proteins from brain tissues were studied using proteomic approaches, Haemotoxylin and Eosin staining, immunohistochemistry, Western blotting, and ingenuity pathway analysis. The expression of Receptor-interacting protein 1(RIPK1) and Caspase 3 were up-regulated and activity-dependent neuroprotective protein (ADNP) was down-regulated in GNMT-KO mice regardless of the age. Besides, proteins related to neuropathology, such as excitatory amino acid transporter 2, calcium/calmodulin-dependent protein kinase type II subunit alpha, and Cu-Zn superoxide dismutase were found only in the group of aged wild-type mice; 4-aminobutyrate amino transferase, limbic system-associated membrane protein, sodium- and chloride-dependent GABA transporter 3 and ProSAAS were found only in the group of young GNMT-KO mice and are related to function of neurons; serum albumin and Rho GDP dissociation inhibitor 1 were found only in the group of aged GNMT-KO mice and are connected to neurodegenerative disorders. With proteomic analyses, a pathway involving Gonadotropin-releasing hormone (GnRH) signal was found to be associated with aging. The GnRH pathway could provide additional information on the mechanism of aging and non-aging related neurodegeneration, and these protein markers may be served in developing future therapeutic treatments to ameliorate aging and prevent diseases.  相似文献   
2.
时间序列是信息系统一储存在的一类重要数据对象,而序列间的距离计算是很多时间序列数据开采或数据提取问题的核心。针对目前的序列距离定义模型对非总体的细微关联特征不敏感的问题,提出了一种新的时间序列距离定义模-时间序列的细微距离MD(X,Y),并提出了一种将时间序列由时域映射到频域,在频域中分离出不同的序列变化形式,以确定时间序列细微差别程度的算法-FDD算法。FDD算法具有较高的效率,且可以 作基准值  相似文献   
3.
Li KW  Wu HH  Lin YC 《Applied ergonomics》2006,37(6):743-748
Slipping and falling are common phenomena in both workplaces and our daily activities. The risks associated with slipping and falling are related to the materials of footwear/floor, contamination condition, and geometric design of the sole. Shoe soles of various tread design are very common. Tread pattern of the shoe affects friction especially under liquid-contaminated conditions. Verification of the effects of tread groove depth is significant in assisting designers in designing proper footwear for workers exposed to slippery floor conditions. In this study, we measured the friction coefficients using the Neolite footwear pads on the terrazzo, steel, and vinyl floors under three liquid-contaminated conditions. A Brungraber Mark II slipmeter was used. The footwear pads had tread grooves with a width of either 3 or 9 mm. The depth of the tread grooves ranged from 1 to 5 mm. The results showed that tread groove depth affected the friction coefficients significantly. Higher friction values were recorded for footwear pads with deeper tread grooves on wet and water–detergent-contaminated floors. The averaged coefficient of friction (COF) gain per tread groove depth increase in millimeter under these two surface conditions ranged from 0.018 to 0.108, depending on the tread groove width, floor, and contaminant.  相似文献   
4.
This study aims to evaluate further the performance of a platelet-rich plasma (PRP) additive incorporated with calcium phosphate bone cement (CPC) in vitro to prove its efficiency as bone graft substitutes and its compatibility to be incorporated into the CPC with other techniques in clinical restoration in vivo. The growth factor release ability and the osteogenic evaluation of PRP, CPC, and PRP/CPC testing groups with 5, 10, and 15 wt.% PRP were compared in vitro. Four groups were measured using non-decalcified staining methods in vivo, which include the testing group of 10 wt.% PRP/CPC selected from the evaluation in vitro, by using both the autograft with rabbit trabecular and CPC-only as comparison groups and the group without grafting material as the control sample. The results obtained through specimen immersion show that growth factor release and alkaline phosphatase activities after osteoprogenitor cell culture had a significantly better effect on 10 and 15 wt.% PRP/CPC than on the other groups in vitro. Analysis results suggest that PRP was still retained in the CPC matrix even after 32 days of immersion. The results in vivo show that the histology of the autograft bone and the control group without grafting material exhibited fibrous connective and adipose tissues, which obviously filled the created cavity even at nine weeks after the operation. Osteoregeneration was more successful in the PRP-additive group, which accumulated bone remodeling than in the other groups. In conclusion, CPC could be a potential carrier with adequate PRP additives that bear a therapeutic potential for enhanced bone tissue regeneration.  相似文献   
5.
6.
The mechanism of precipitation for substances produced by the reductive decomposition of a nonaqueous electrolyte solution (NES) at a graphite electrode (GE) was investigated with the help of classical thermodynamics in this paper. It was found that the substances tend to precipitate from a supersaturated NES by overcoming a Gibbs free energy barrier. This requires the atoms or molecules of the substances to initially aggregate into a stable solid nucleus, which will grow continuously into a macroscopic solid particle subsequently. When the Gibbs free energy barrier is reduced to zero under a certain condition, the substances will precipitate from the supersaturated NES as a two-dimensional (2D) solid layer on the GE surface in a nucleationless manner. Moreover, when the sum of the substance-NES interaction and the substance-GE interaction is stronger than the GE-NES interaction, the substances will even precipitate from an unsaturated NES as a 2D solid layer on the GE surface, provided the unsaturation potential is not too high.  相似文献   
7.
A composite plate containing piezoceramics on both the upper and bottom surfaces is considered. Based on the piezoelectricity with consideration for the coupling between the strain field and the electric field, a finite element formulation is developed. An eight-node three-dimensional brick element is used, and three-dimensional incompatible modes are introduced to take into account the bending behavior of the structure. The response of the structure and the sensor electrical outputs subjected to thermal loading as well as the required voltage that should be applied to reduce the deflection resulting from thermal loading are analyzed. In addition, this study also analyzes the effect of coupling between the strain field and the electrical field. It shows that the coupling effect may not be negligible; the larger the piezoelectric constant, or the thinner the main structure, the larger the coupling effect will be.  相似文献   
8.
This study investigates the feasibility of a high-performance ZnO piezoelectric transducer for wind-power generation applications. The piezoelectric transducer is constructed of a Cu/ZnO/ITO/PET structure. Closely examining the ITO/PET substrate by a nano indenter reveals a low Young's modulus of 6.62 Gpa for specific deflections. The ZnO piezoelectric film of 965 nm is deposited on ITO/PET substrate using a RF magnetron sputtering system at room temperature. A copper layer is attached to the ZnO/ITO/PET structure to construct piezoelectric transducers. Both scanning electron microscopy and X-ray diffraction indicate that, among the favorable characteristic of the ZnO piezoelectric film include a rigid surface structure and a high c-axis preferred orientation. According to cantilever vibration theory, a transducer with a cantilever length of 9.9 mm and vibration area of 1.5 cm2 is designed for natural wind. An appropriate mass loading of 0.57 g on the cantilever is critical for increasing the vibration amplitude and promoting the generated power of a piezoelectric transducer. Finally, an open circuit voltage of 1.87 V for the ZnO piezoelectric transducer at a vibration frequency of 100 Hz is obtained by an oscilloscope. After rectifying and filtering, the output power of the generator exhibits an available benefit of 0.07 μW/cm2 with the load resistance of 5 MΩ.  相似文献   
9.
Frequency hopping sequences with optimal partial autocorrelation properties   总被引:2,自引:0,他引:2  
We classify some p/sup k/-ary (p prime, k integer) generalized m-sequences and generalized Gordon-Mills-Welch (GMW) sequences of period p/sup 2k/-1 over a residue class ring R=GF(p)[/spl xi/]/(/spl xi//sup k/) having optimal partial Hamming autocorrelation properties. In frequency hopping (FH) spread-spectrum systems, these sequences are useful for synchronizing process. Suppose, for example, that a transmitting p/sup k/-ary FH patterns of period p/sup 2k/-1 are correlated at a receiver. Usually, the length of a correlation window, denoted by L, is shorter than the pattern's overall period. In that case, the maximum value of the out-of-phase Hamming autocorrelation is lower-bounded by /spl lceil/L/p/sup k/+1/spl rceil/ but the classified sequences achieve this bound with equality for any positive integer L.  相似文献   
10.
基于频域介电谱试验的750kV变压器绝缘状况评估   总被引:1,自引:1,他引:0  
电力变压器运行的可靠性在很大程度上取决于其绝缘系统,绝缘性能降低,寿命便缩短。从经济性和安全性考虑,希望尽可能延长变压器的使用年限,又确保其安全稳定运行,则要对其进行绝缘诊断和寿命评估。通过分析电力变压器绝缘状态的诊断原理与方法,介绍了一种基于频域介电谱(FDS)技术进行绝缘诊断的新型试验方法。采用FDS法对兰州东变电站750 kV变压器进行了初步的现场测量,并分析了测量结果,结果表明,该变压器纸板水分含量合格,绝缘状况良好,且测量结果与预防性试验吻合良好。FDS有望成为一种新的预防性试验方法,具有良好的应用前景。  相似文献   
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