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排序方式: 共有86条查询结果,搜索用时 15 毫秒
1.
We studied urinary N-acetyl-beta-D-glucosaminidase (NAG) in the early stage of diabetic nephropathy in 27 non-insulin-dependent diabetes mellitus (NIDDM) patients with a microalbumin level below 20 mg on 24-hour urine sample. Microalbumin and NAG excretion were measured in 24-hour urine samples collected on three separate occasions within seven days of admission. Creatinine clearance was determined simultaneously. There was a significant negative correlation between the creatinine clearance and 24-hour urinary NAG (r = -0.38, p < 0.05). Elevation of urinary NAG may indicate decreased renal function during early stage NIDDM nephropathy.  相似文献   
2.
GaGdN layers were grown at temperatures below 300°C by radio-frequency plasma-assisted molecular beam epitaxy on sapphire substrates. GaGdN samples with high Gd concentration as high as 12.5% were obtained by lowering the growth temperature. X-ray diffraction results showed no obvious secondary phase, which means that the phase separation can be suppressed by the growth at low temperatures. All samples, including those grown at room temperature, showed ferromagnetic characteristics. Photoluminescence emission was observed, though spectra exhibit broad and sharp luminescence bands related to many kinds of defects. It is suggested that electrons coming from defects, especially, nitrogen vacancy, stabilize ferromagnetism, and that the carrier-induced ferromagnetism occurs in the low-temperature-growth GaGdN.  相似文献   
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A goodness-of-fit testing procedure for Archimedean copula (AC) models is developed based on right-censored data. The proposed approach extends an existing method, which is suitable for the Clayton model, to general AC models. Asymptotic properties of the proposed test statistics under the true model assumption are derived. Simulation analysis shows that the proposed test has reasonable performance. Finally, two real data examples are analyzed for illustrative purposes.  相似文献   
5.
Detecting when the process has changed is a classical problem in sequential analysis and is an important practical issue in statistical process control. This article is concerned about the binomial cumulative sum (CUSUM) control chart, which is extensively applied to industrial process control, health care, public health surveillance, and other fields. For the binomial CUSUM, a maximum likelihood estimator has been proposed to estimate the change point. In our article, following a decision theoretic approach, we develop a new estimator that aims to improve the existing methods. For interval estimation, we propose a parametric bootstrap procedure to construct the confidence set of the change point. We compare our proposed method with the maximum likelihood estimator and Page's last zero estimator in terms of mean squared error by simulations. We find that the proposed method gives more unbiased and robust results than the existing procedures under various parameter designs. We analyze jewelry manufacturing data for illustration.  相似文献   
6.
Annealing Effect in GaDyN on Optical and Magnetic Properties   总被引:1,自引:0,他引:1  
The annealing effect on the optical and magnetic properties of the GaDyN layers was studied. The PL intensities of yellow and green bands as well as the intra-4f orbital transition of Dy3+ ions were found to decrease for the samples annealed at 900 and 1000 °C. It is supposed that the intra-4f orbital transition is related to the broad peak luminescence coming from defects. Increasing the annealing temperature, the magnetization becomes smaller. It is considerable that the number of electrons coming from defects was reduced by the annealing treatments and that the ferromagnetism in GaDyN is attributed as carrier induced ferromagnetism.  相似文献   
7.
介绍一种具有感觉系统、能够四足步行的仿生人造牲畜。该仿生人造牲畜具有12个自由度,关节采用滑块摆杆机械,由伺服电机驱动,其感觉系统由身体上的姿势传感器、脚上的力传感器以及与伺服电机同轴安装的轴角编码器构成。该仿生人造牲畜的步行由计算机进行控制。  相似文献   
8.
High receiver sensitivity (?51.9 dBm) and long span (243 km) transmission expriments have been achieved with a 140 Mbit/s optical FSK heterodyne single-filter detection system, using a phase-tunable DFB laser diode as a transmitter. This has enabled direct FSK modulation without waveform distortion. Also, a 280 Mbit/s 204 km transmission experiment has been carried out successfully.  相似文献   
9.
A 2.5-Gb/s CPFSK four-channel FDM transmission experiment has been conducted with a 150-km-long nondispersion-shifted fiber. This system employed a wideband channel space controller, a common polarization control, and a channel identification function. These were indispensable for realizing a high-capacity, coherent FDM trunk line system. The results of the experiment confirm the feasibility of trunk line systems with over 160-Gb/s capacity  相似文献   
10.
Endothelin (ET) and its receptor system have been shown to exert various biological effects on different types of cells in addition to their well-known vasoconstrictor activity. Recently ET-1, ET-3 and the ETB receptor have been shown to play an important role in the development of neural crest-derived cells and, in this context, pheochromocytomas have been reported to harbor ET-1. Endothelin-3 or ET receptor subtypes, however, have not been examined in pheochromocytoma and paraganglioma so far. In the present study the immunohistochemical localization of ET-1/big ET-1, ET-3/big ET-3 and the ETA and ETB receptors were investigated to clarify the biological characteristics of these two tumors using 32 pheochromocytomas and 11 extra-adrenal paragangliomas. Endothelin-1/big ET-1 was detected in 19 pheochromocytomas (59%) and eight paragangliomas (72%), while ET-3/big ET-3 was detected in 10 pheochromocytomas (31%) and three paragangliomas (27%). The ETA receptor was found in 21 pheochromocytomas (66%) and in eight paragangliomas (73%), while the ETB receptor was found in 25 pheochromocytomas (78%) and in eight paragangliomas (73%). Normal adrenomedullary cells lacked each antigen examined. Endothelin-immunoreactive tumor cells were distributed focally or in a manner scattered, while receptor-immunostained tumor cells were distributed with a focal pattern for the ETA receptor and with a focal or diffuse pattern for the ETB receptor. Endothelin and its receptor coexisted in the same tumor in 21 of 28 ET-positive pheochromocytomas and in eight of 10 ET-positive paragangliomas. In addition, seven pheochromocytomas and two paragangliomas revealed positivity of the receptor(s) irrespective of the absence of ET-immunoreactivity. In conclusion, ET and its receptor are frequently and concomitantly expressed in the pheochromocytoma and paraganglioma. From the highly frequent expression of this system or the receptor(s), ET-receptor-mediated signal transduction of these tumors concerning growth and/or cell survival is expected, although definite biological significance of this ligand-receptor system in these tumors awaits further investigation.  相似文献   
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