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排序方式: 共有838条查询结果,搜索用时 15 毫秒
831.
832.
Daphnia swimming behavior during vertical migration 总被引:2,自引:0,他引:2
Dodson Stanley I.; Tollrian Ralph; Lampert Winfried 《Journal of plankton research》1997,19(8):969-978
We observed the individual swimming behavior of a clone of Daphniahyalina swiniming freely inside a mesocosm-scale plankton tower.Changes in light intensity and the presence or absence of fishsmell induced vertical migration through 相似文献
833.
Jakob Beyer Samir Jabari Tilman T. Rau Winfried Neuhuber Axel Brehmer 《Histochemistry and cell biology》2013,140(2):157-167
The submucous layers of human small and large intestines contain at least two separate neuron populations. Besides morphological features, they differ in their immunoreactivities for calretinin (CALR) and somatostatin (SOM), respectively. In this study, submucosal wholemounts of 23 patients or body donors (including all segments of small intestine and colon) were immunohistochemically quadruple stained for CALR and SOM as well as for substance P (SP) and choline acetyltransferase (ChAT). We found that all SOM-positive neurons co-stained for ChAT and the majority for SP [between 50 % in the small intestinal external submucosal plexus (ESP) and 75 % in the colonic ESP]. In contrast, a majority of CALR-neurons contained ChAT (between 77 % in the small intestinal ESP and 92 % in the large intestinal ESP) whereas less than 4 % of CALR-neurons were co-immunoreactive for SP. Another set of wholemounts was co-stained for peripherin, a marker enabling morphological analysis. Where identifiable, both SOM alone- and SOM/SP-neurons displayed a uniaxonal (supposed pseudouniaxonal) morphology. We suggest that the chemical code of SOM-immunoreactive, human submucosal neurons may be “ChAT+/SOM+/SP±”. In additional sections double stained for SOM and SP, we regularly found double-labelled nerve fibres only in the mucosa. In contrast, around submucosal arteries mostly SOM alone- fibres were found and the muscularis propria contained numerous SP-alone fibres. We conclude that the main target of submucosal SOM(/SP)-neurons may be the mucosa. Due to their morpho-chemical similarity to human myenteric type II neurons, we further suggest that one function of human submucosal SOM-neurons may be a primary afferent one. 相似文献
834.
This article comments on: Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology? 相似文献
835.
Functions of Soil for Society and the Environment 总被引:3,自引:0,他引:3
Six key environmental, social and economic functions of soil are described, as well as the reversible and irreversible threats,
caused by their uses. Sustainable use of soil is defined by the temporal and/or spatial (local or regional) harmonisation
in the uses of the 6 functions, excluding or minimising irreversible ones, which is not a scientific but a political task. 相似文献
836.
837.
838.
Michael Hoffmann Mathias Schmidt Winfried Wels 《Cancer immunology, immunotherapy : CII》1998,47(3):167-175
Tumor necrosis factor (TNF)-α has a broad range of biological activities, which depend heavily on cell type and physiological
condition. In a panel of human tumor cell lines we analyzed expression of the receptor tyrosine kinases EGFR, ErbB2 and ErbB3,
and the response to TNF-α. Among the cell lines tested those resistant to TNF-α were found to express high levels of either
EGFR, or ErbB2 and ErbB3. In TNF-sensitive breast and cervical carcinoma cells activation of EGFR or ErbB2 by the exogenous
growth factors EGF and heregulin β1 resulted in a significant increase in the number of cells surviving TNF-α treatment. In
contrast, inhibition of EGFR activation in TNF-resistant breast carcinoma cells by the novel antagonistic anti-EGFR antibody
14E1 sensitized the cells to the cytotoxic effects of TNF-α. A bacterially expressed fusion protein consisting of a 14E1 single-chain
(sc) Fv antibody fragment linked to human TNF-α retained TNF-α activity. This scFv(14E1)-TNF-α molecule localized specifically
to EGFR on the surface of tumor cells and activated the NF-κB pathway in co-cultured T cells, as demonstrated by electrophoretic
mobility shift assays.
Received: 6 May 1998 / Accepted: 16 July 1998 相似文献