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排序方式: 共有114条查询结果,搜索用时 15 毫秒
31.
32.
A reproducible in vivo d-LSD binding method in rat brain is described, with high affinity (Kd of 5 pmoles/g wet wt), stereospecificity (d- vs. 1-LSD) and regional selectivity. It may be a useful adjunct to in vitro methods for measuring changes in turnover at the synaptic level related to the intact receptor. 相似文献
33.
Any state of matter is classified according to its order, and the type of order that a physical system can possess is profoundly affected by its dimensionality. Conventional long-range order, as in a ferromagnet or a crystal, is common in three-dimensional systems at low temperature. However, in two-dimensional systems with a continuous symmetry, true long-range order is destroyed by thermal fluctuations at any finite temperature. Consequently, for the case of identical bosons, a uniform two-dimensional fluid cannot undergo Bose-Einstein condensation, in contrast to the three-dimensional case. However, the two-dimensional system can form a 'quasi-condensate' and become superfluid below a finite critical temperature. The Berezinskii-Kosterlitz-Thouless (BKT) theory associates this phase transition with the emergence of a topological order, resulting from the pairing of vortices with opposite circulation. Above the critical temperature, proliferation of unbound vortices is expected. Here we report the observation of a BKT-type crossover in a trapped quantum degenerate gas of rubidium atoms. Using a matter wave heterodyning technique, we observe both the long-wavelength fluctuations of the quasi-condensate phase and the free vortices. At low temperatures, the gas is quasi-coherent on the length scale set by the system size. As the temperature is increased, the loss of long-range coherence coincides with the onset of proliferation of free vortices. Our results provide direct experimental evidence for the microscopic mechanism underlying the BKT theory, and raise new questions regarding coherence and superfluidity in mesoscopic systems. 相似文献
34.
Roblick UJ Hirschberg D Habermann JK Palmberg C Becker S Krüger S Gustafsson M Bruch HP Franzén B Ried T Bergmann T Auer G Jörnvall H 《Cellular and molecular life sciences : CMLS》2004,61(10):1246-1255
Changes in the proteome of colon mucosal cells accompany the transition from normal mucosa via adenoma and invasive cancer to metastatic disease. Samples from 15 patients with sporadic sigmoid cancers were analyzed. Proteins were separated by two-dimensional gel electrophoresis. Relative differences in expression levels between normal tissue, adenoma, carcinoma and metastasis were evaluated in both intra- and inter-patient comparisons. Up- and down-regulated proteins (<twofold) during development to cancer or metastasis were excised and submitted to peptide mass fingerprinting and MS/MS sequence analysis, facilitated by the use of a compact disc workstation. In total, 112 protein spots were found to be differentially regulated, of which 72 were determined as to protein identity, 46 being up-regulated toward the progression of cancer, and 26 down-regulated. Several of the identifications correlate with proteins of the cell cycle, cytoskeleton or metabolic pathways. The pattern changes now identified have the potential for design of marker panels for assistance in diagnostics and therapeutic strategies in colorectal cancer.Received 2 February 2004; received after revision 16 March 2004; accepted 18 March 2004 相似文献
35.
Tímea Szederjesi Tomáš Pavlíček Orsolya Márton Virág Krízsik Csaba Csuzdi 《Journal of Natural History》2019,53(5-6):301-314
Dendrobaena veneta is one of the most widely used compost worms now distributed all over Europe and has been described under several synonymous names. Besides the typical stripy red specimens, another form bearing pinkish pigmentation also exists, mostly found in natural habitats in the East Mediterranean. Here we provide the first integrative taxonomic analysis of D. veneta, including some closely related species. Both the morphological and molecular results highly support the resurrection of D. succinta, a former synonym of D. veneta. In addition, we describe a peculiar new species, D. karacadagi sp. n. from Anatolia, and prove the highly homoplasious character of the cross section of the longitudinal musculature.
urn:lsid:zoobank.org:pub:336D3F7A-AEA1-465B-9096-03070C761A6A 相似文献
36.
Analytic and Dynamic Approach to Collaboration: A Transdisciplinary Case Study on Sustainable Landscape Development in a Swiss Prealpine Region 总被引:1,自引:0,他引:1
Michael Stauffacher Thomas Flüeler Pius Krütli Roland W. Scholz 《Systemic Practice and Action Research》2008,21(6):409-422
The involvement of stakeholders and the public in societal decision processes has lately received increased attention. We
suggest that appropriate and tailored techniques should be selected and integrated to provide the prerequisites for inclusive
involvement depending on the issue, type, goals and phase of the decision process in question, i.e. an analytic, systematic
and dynamic approach to collaboration. In a transdisciplinary case study design we integrate diverse analytical methods whereby
a process of mutual learning between science and people from outside academia is strived for. Our framework for collaboration
is illustrated by a case study on sustainable landscape development in the Swiss prealpine region of Appenzell Ausserrhoden.
相似文献
Michael StauffacherEmail: |
37.
Silencing of microRNAs in vivo with 'antagomirs' 总被引:2,自引:0,他引:2
Krützfeldt J Rajewsky N Braich R Rajeev KG Tuschl T Manoharan M Stoffel M 《Nature》2005,438(7068):685-689
MicroRNAs (miRNAs) are an abundant class of non-coding RNAs that are believed to be important in many biological processes through regulation of gene expression. The precise molecular function of miRNAs in mammals is largely unknown and a better understanding will require loss-of-function studies in vivo. Here we show that a novel class of chemically engineered oligonucleotides, termed 'antagomirs', are efficient and specific silencers of endogenous miRNAs in mice. Intravenous administration of antagomirs against miR-16, miR-122, miR-192 and miR-194 resulted in a marked reduction of corresponding miRNA levels in liver, lung, kidney, heart, intestine, fat, skin, bone marrow, muscle, ovaries and adrenals. The silencing of endogenous miRNAs by this novel method is specific, efficient and long-lasting. The biological significance of silencing miRNAs with the use of antagomirs was studied for miR-122, an abundant liver-specific miRNA. Gene expression and bioinformatic analysis of messenger RNA from antagomir-treated animals revealed that the 3' untranslated regions of upregulated genes are strongly enriched in miR-122 recognition motifs, whereas downregulated genes are depleted in these motifs. Analysis of the functional annotation of downregulated genes specifically predicted that cholesterol biosynthesis genes would be affected by miR-122, and plasma cholesterol measurements showed reduced levels in antagomir-122-treated mice. Our findings show that antagomirs are powerful tools to silence specific miRNAs in vivo and may represent a therapeutic strategy for silencing miRNAs in disease. 相似文献
38.
Zusammenfassung Die Histaminfreisetzung in peritonealen Mastzellen der Ratte, hervorgerufen durch Toluidinblau, wurde in vitro studiert und festgestellt, dass Toluidinblau vor allem auf die Feinstruktur der Mastzellgranula und deren unmittelbare Umgebung einwirkt, wodurch Cytoplasmabläschen entstehen. Diese setzen sich wahrscheinlich mit dem extra-zellulären Raum in Verbindung, woraus geschlossen wird, dass das Auswandern von Granula aus dem Zellbereich keine Vorbedingung für die Histaminfreisetzung darstellt.
The authors are indebted to MissMarianne Borg for technical assistance and the Swedish Medical Research Council and the Magnus Bergvall Foundation for grants. We also gratefully acknowledge the use of the Stereoscan S-4 scanning electron microscope which is a gift to the University of Umeå from the Knut and Alice Wallenberg Foundation. 相似文献
The authors are indebted to MissMarianne Borg for technical assistance and the Swedish Medical Research Council and the Magnus Bergvall Foundation for grants. We also gratefully acknowledge the use of the Stereoscan S-4 scanning electron microscope which is a gift to the University of Umeå from the Knut and Alice Wallenberg Foundation. 相似文献
39.
H. Kröger E. Stutz M. Rother S. Niehoff 《Cellular and molecular life sciences : CMLS》1966,22(5):300-301
Zusammenfassung Intravenöse Injektion von Ascites-Zellen des Yoshida-Sarkoms in Ratten bewirkte, dass 27 Tage nach der Applikation 16 von 17 Tieren gestorben sind. Dasselbe Ergebnis wurde erhalten bei Injektion von normalem Serum oder bei der Kombination dieses Serums mit 6-Mercaptopurin. Dagegen führte gleichzeitige Applikation von Antiserum und 6-Mercaptopurin zu der erstaunlichen Tatsache, dass nach 40 Tagen etwa 60% der so behandelten Tiere keinen Tumor aufwiesen. 相似文献
40.