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排序方式: 共有261条查询结果,搜索用时 15 毫秒
1.
OL Lopez RP Brenner JT Becker RF Ulrich F Boller ST DeKosky 《Canadian Metallurgical Quarterly》1997,48(6):1521-1525
We examined whether either psychotic features (e.g., delusions and hallucinations) or EEG abnormalities are associated with more rapid progression of Alzheimer's disease (AD). AD patients with psychosis have exhibited more EEG abnormalities than those without psychosis, and both abnormal EEG and psychosis have been noted to be predictors of functional and cognitive decline in AD. Ninety-five probable AD patients participating in a longitudinal study of dementia had an EEG and a semistructured psychiatric interview at baseline. Using EEG spectral analysis, we classified records as normal/abnormal based on the parasagittal mean frequency. Patients with abnormal EEGs were more functionally (e.g., Blessed Rating Scale for activities of daily living) and cognitively (e.g., Mini-Mental State) impaired than patients with normal EEG. AD patients with psychosis were only more functionally impaired than patients without psychosis. A two-factor analysis showed no interaction between abnormal EEG and psychosis. In addition, using a Cox proportional hazard model adjusted for age and education, the presence of an abnormal EEG or psychotic symptom at study entry was associated with higher risk of reaching severe cognitive and functional impairment during follow-up. Neither abnormal EEG nor the presence of psychosis predicted death. These results indicate that both abnormal EEG and psychosis are independent predictors of disease progression but not of physical survival. 相似文献
2.
T. I. Voronina T. S. Lagunova M. P. Mikhailova K. D. Moiseev M. A. Sipovskaya Yu. P. Yakovlev 《Semiconductors》1997,31(8):763-767
Galvanomagnetic phenomena and photoconductivity in broken-gap type-II GaInAsSb/p-InAs heterojunctions with different levels of doping of the solid solution with donor (Te) or acceptor (Zn) impurities have
been investigated. It has been determined that in such structures an electronic channel, which determines the galvanomagnetic
effects in a wide range of doping levels, is present at the heterojunction. A sharp decrease of the Hall mobility was observed
in the experimental heterostructures with a high level of doping of the epitaxial layer with an acceptor impurity. The observed
effect is due to exhaustion of the electronic channel as a result of carrier localization in potential wells at the heterojunction.
Fiz. Tekh. Poluprovodn. 31, 897–901 (August 1997) 相似文献
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5.
It has been shown that rabbit liver NAD-kinase is a Ca(2+)-dependent, calmodulin-regulated enzyme. Differences were found between the sensitivity of the alpha- and beta-forms of the enzyme to calmodulin. The maximal activation of the NAD-kinase alpha-form was observed at a calmodulin/NAD-kinase ratio equal to 2, that of the beta-form--at 4. Further increases in the above parameter (up to 10) had no effect on the activity of the alpha-form, whereas that of the beta-form dropped down to the initial (basal) level. 相似文献
6.
P. G. Bannov G. E. Shumilova N. A. Voronina O. V. Yurkina T. F. Alekseenko 《Chemistry and Technology of Fuels and Oils》1992,28(3):178-179
Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 3, pp. 34–35, March, 1992. 相似文献
7.
AR Elbers PJ Blaauw M de Vries PJ van Gulick OL Smithuis RP Gerrits MJ Tielen 《Canadian Metallurgical Quarterly》1996,18(4):127-131
The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non-practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty-two per cent of the participants were overweight, and relatively more non-practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezing) reported by the vets predominantly working in swine and/or poultry practice could be caused by irritation and/or inflammation of the first part of the trachea-bronchial tree that has no measurable and permanent consequences for changes in lung function or increased bronchial hyperreactivity. The results of a skin test against allergens and determination of allergen-specific IgE in blood indicated that the respiratory complaints were probably not related to allergy against the panel of allergens tested. 相似文献
8.
T. I. Voronina T. S. Lagunova M. P. Mikhaĭlova K. D. Moiseev A. F. Lipaev Yu. P. Yakovlev 《Semiconductors》2006,40(5):503-520
The results of detailed study of the magnetotransport properties of broken-gap type II heterojunctions in a GaInAsSb/InAs(GaSb) system are reported. An electron channel with a high charge-carrier mobility (as high as 50000–60000 cm2/(V s)) is observed and studied for the first time in an isotype broken-gap p-GaInAsSb/p-InAs heterostructure. The effects of electron-channel depletion and semimetal-semiconductor transition in the case of heavy doping of the quaternary alloy with acceptors are studied. Magnetotransport properties at temperatures of 4.2–200 K are studied in detail. Data on the energy spectrum and parameters of two-dimensional charge carriers at the heteroboundary are obtained. It is ascertained experimentally that, depending on the composition, either staggered (at x = 0.85) or broken-gap (at x = 0.95) heterojunctions can be formed in the Ga1?x InxAsySb1?y /GaSb, which is confirmed by theoretical calculations. The anomalous Hall effect and negative magnetoresistance were observed in GaInAsSb/InAs:Mn grown on substrates doped heavily with Mn magnetic acceptor impurity so that the hole concentration was as high as p > 5 × 1018 cm?3; these phenomena are caused by exchange interaction of Mn ions in InAs with high-mobility charge carriers in the electron channel at the heterointerface. 相似文献
9.
This report describes a presumed choroidal granuloma with vitreous hemorrhage resembling choroidal melanoma. A healthy 31-year-old man, who had progressive vision loss in the right eye during 1 month, was found to have a yellow-white juxtapapillary choroidal mass. Fluorescein angiography demonstrated a choroidal neovascular membrane over the lesion. There was focal persistent hypofluorescence in the late phase of fluorescein angiography. The thickness of the lesion increased from 3.0 mm to 7.1 mm during 1 month. Subretinal and vitreous hemorrhage developed. The patient was suspected to have a choroidal granuloma and choroidal neovascular membrane, and was treated with oral steroids. Ten months later, the vitreous blood cleared completely with an attached retina. Control of inflammation may have a role in the treatment of idiopathic choroidal granulomas and some choroidal neovascular membranes secondary to ocular inflammation. 相似文献
10.
1. | Raising the cobalt concentration from 0 to 40% improves the oxidation resistance of Ni–20Cr alloys, since the amount of Cr2O3 in the scale increases. The oxidation resistance is highest for the alloy with 40% Co. Larger amounts of Co up to 70% lead to the formation of CoO in the scale and smaller amounts of chromium oxide, which has a negative effect on the oxidation resistance of Ni–Cr alloys. |
2. | The addition of up to 25% Fe to Ni–20Cr–Co alloys reduces the amount of Cr2O3 in the scale and lowers the oxidation resistance. With larger amounts of Fe the amount of Cr2O3 in the scale again increases, the oxidation resistance increasing correspondingly. Alloys with 45% Fe have the same oxidation resistance as alloys without Fe. |