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排序方式: 共有6005条查询结果,搜索用时 15 毫秒
1.
The northern Great Plains (NGP) of the United States has been a hotspot of West Nile virus (WNV) incidence since 2002. Mosquito ecology and the transmission of vector-borne disease are influenced by multiple environmental factors, and climatic variability is an important driver of inter-annual variation in WNV transmission risk. This study applied multiple environmental predictors including land surface temperature (LST), the normalized difference vegetation index (NDVI) and actual evapotranspiration (ETa) derived from Moderate-Resolution Imaging Spectroradiometer (MODIS) products to establish prediction models for WNV risk in the NGP. These environmental metrics are sensitive to seasonal and inter-annual fluctuations in temperature and precipitation, and are hypothesized to influence mosquito population dynamics and WNV transmission. Non-linear generalized additive models (GAMs) were used to evaluate the influences of deviations of cumulative LST, NDVI, and ETa on inter-annual variations of WNV incidence from 2004–2010. The models were sensitive to the timing of spring green up (measured with NDVI), temperature variability in early spring and summer (measured with LST), and moisture availability from late spring through early summer (measured with ETa), highlighting seasonal changes in the influences of climatic fluctuations on WNV transmission. Predictions based on these variables indicated a low WNV risk across the NGP in 2011, which is concordant with the low case reports in this year. Environmental monitoring using remote-sensed data can contribute to surveillance of WNV risk and prediction of future WNV outbreaks in space and time. 相似文献
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P物质在家兔延髓腹侧面加压区的升压作用及其机制探讨 总被引:3,自引:0,他引:3
在乌拉坦麻醉,三碘季铵酚制动,人工呼吸的家兔上观察到,延髓腹侧面加压区给予P物质使血压呈剂量依赖性升高,但对心率无明显影响。VSMp给予SP受体阻断使BP明显降低并可阻断SP升压效应,VSMp给予酚妥拉明或哌唑嗪预处理使SP升压效应减弱或消失,而给予育亨宾或心得安对SP升压效应无明显影响。VSMp给予SP可使肾交感神经放电显著增加,并伴有BP显著升高;VSMp给予DSP使RSND和BP明显降低并可 相似文献
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F C Wei L H Colony H C Chen C C Chuang M S Noordhoff 《Plastic and reconstructive surgery》1989,84(4):651-661
Historically, restoration of hand function following multiple digital amputation has been unsatisfactory. The evolution of digital reconstruction with toe transfer has enabled surgeons to reestablish prehension in these severely injured hands. A 4-year experience with 26 consecutive combined second and third toe transfers to replace missing adjacent fingers was reviewed in order to delineate the indications and technical considerations and to emphasize prevention of donor-site complications. Combined second and third toe transfer is reserved for adjacent finger amputations proximal to the digital web space with remaining fingers no longer than the small finger. Radial amputations are replaced with contralateral combined toe units, while ipsilateral toes are more ideal for ulnar amputations. Limited dorsal and plantar skin flaps extending only to the midpoint of the first and third digital web spaces allow for direct donor-site closure and uncomplicated healing. Maintenance of the plantar metatarsal arch by avoiding metatarsal shaft osteotomies or bone grafting-shortened metatarsals eliminates potential gait disturbances. When properly applied in selected patients, this single-stage microsurgical procedure can restore prehensile function, improve the appearance of the hand with multiple digital amputations, and preserve near-normal donor-foot function. 相似文献
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The groin flap is a reliable and well-established reconstructive option for pedicled or free-tissue transfer. Concern regarding its variable vascular origin and caliber has limited its use. To overcome this, a simplified guideline based on the transverse diameter of the patient's index and long fingers at the distal interphalangeal level has been developed. Thus "rule of two finger widths" positions the origin of the vascular pedicle from the femoral vessels two finger widths below the inguinal ligament, the upper flap border two finger widths above the inguinal ligament, the lower flap border two finger widths below the vascular origin, and both parallel to the flap axis, which lies along a line from the vascular origin to the anterosuperior iliac spine. This new groin flap design provides the necessary guidelines for vascular identification, accommodates pediatric and adult stature, and ensures primary donor-site closure if flap dimensions are within the prescribed boundaries. In addition, a new sartorius-cutaneous groin flap is presented. This combines the cutaneous groin flap with the proximal sartorius muscle (up to 15 cm), which is supplied by the deep vessels of the superficial circumflex iliac system. The sartorius-cutaneous groin flap further emphasizes the concept of single-pedicle compound or combined flaps and additionally enhances the extensive reconstructive versatility of previously described groin flaps. Over 200 pedicled and free groin flaps have been performed according to the "rule of two finger widths" over the past 5 years. There have been no complications related to flap design, such as difficulty with flap elevation, marginal necrosis, or donor-site closure.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Isolation and purification of protein kinase C from human leukemia ML-1 cells phosphorylation of human leukemia RNA polymerase II in vitro 总被引:1,自引:0,他引:1
Protein kinase C (PKC) was purified to near homogeneity from human leukemia ML-1 cells. The purified enzyme showed a single polypeptide band of 80 kDa on SDS-polyacrylamide gel after electrophoresis, and was totally dependent on Ca2+/phospholipid for activity. Diacylglycerol and the tumor-promoting on Ca2/phospholipid for activity. Diacylglycerol and the tumor-promoting phorbol esters stimulated the enzyme activity. Autophosphorylation of PKC purified from phenyl-Sepharose column showed both 80- and 37 kDa polypeptides. Further fractionation of PKC on a hydroxyapatite column revealed two peaks of enzyme activity, indicating that there may be two different forms of protein kinase C present in human leukemia cells. The purified PKC was used to phosphorylate RNA polymerase II of human leukemia cells in vitro and the autoradiogram showed that RNA polymerase II large subunits (240, 220 and 150 kDa) were phosphorylated in a time-dependent manner. 相似文献
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L F Wang R H Doi L F Chuang B I Osburn J Maisonnave E Benjamini R Y Chuang 《Biochemical and biophysical research communications》1989,162(2):892-899
The cDNA coding for the major nonstructural protein, NS1, of bluetongue serotype 17 (BTV-17) was cloned previously. Using pUC plasmids, we have successfully expressed the NS1 protein in Escherichia coli as a LacZ-NS1 fusion protein. The recombinant NS1 protein reacted with rabbit anti-BTV-17 antiserum, and was thus immunologically indistinguishable from the native BTV-17 NS1 protein. This was the first bluetongue viral protein to be produced in a bacterial system. 相似文献