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G. Carli M. Sabourin G. Silvano S. Vierucci 《Cellular and molecular life sciences : CMLS》1976,32(11):1441-1442
Summary During avoidance conditioning heart rate levels tend to increase or to decrease according to their initial values and these changes are not related to learning or performance of the task. 相似文献
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Jarillo-Herrero P Kong J van der Zant HS Dekker C Kouwenhoven LP De Franceschi S 《Nature》2005,434(7032):484-488
Progress in the fabrication of nanometre-scale electronic devices is opening new opportunities to uncover deeper aspects of the Kondo effect--a characteristic phenomenon in the physics of strongly correlated electrons. Artificial single-impurity Kondo systems have been realized in various nanostructures, including semiconductor quantum dots, carbon nanotubes and individual molecules. The Kondo effect is usually regarded as a spin-related phenomenon, namely the coherent exchange of the spin between a localized state and a Fermi sea of delocalized electrons. In principle, however, the role of the spin could be replaced by other degrees of freedom, such as an orbital quantum number. Here we show that the unique electronic structure of carbon nanotubes enables the observation of a purely orbital Kondo effect. We use a magnetic field to tune spin-polarized states into orbital degeneracy and conclude that the orbital quantum number is conserved during tunnelling. When orbital and spin degeneracies are present simultaneously, we observe a strongly enhanced Kondo effect, with a multiple splitting of the Kondo resonance at finite field and predicted to obey a so-called SU4 symmetry. 相似文献
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When two superconductors are electrically connected by a weak link--such as a tunnel barrier--a zero-resistance supercurrent can flow. This supercurrent is carried by Cooper pairs of electrons with a combined charge of twice the elementary charge, e. The 2e charge quantum is clearly visible in the height of voltage steps in Josephson junctions under microwave irradiation, and in the magnetic flux periodicity of h/2e (where h is Planck's constant) in superconducting quantum interference devices. Here we study supercurrents through a quantum dot created in a semiconductor nanowire by local electrostatic gating. Owing to strong Coulomb interaction, electrons only tunnel one-by-one through the discrete energy levels of the quantum dot. This nevertheless can yield a supercurrent when subsequent tunnel events are coherent. These quantum coherent tunnelling processes can result in either a positive or a negative supercurrent, that is, in a normal or a pi-junction, respectively. We demonstrate that the supercurrent reverses sign by adding a single electron spin to the quantum dot. When excited states of the quantum dot are involved in transport, the supercurrent sign also depends on the character of the orbital wavefunctions. 相似文献
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TRAIL promotes the survival,migration and proliferation of vascular smooth muscle cells 总被引:4,自引:0,他引:4
Secchiero P Zerbinati C Rimondi E Corallini F Milani D Grill V Forti G Capitani S Zauli G 《Cellular and molecular life sciences : CMLS》2004,61(15):1965-1974
Human and rat primary sub-cultured vascular smooth muscle cells (VSMCs) showed clear expression of the
death receptors TRAIL-R1 and TRAIL-R2; however, recombinant soluble TRAIL did not induce cell death when added to
these cells. TRAIL tended to protect rat VSMCs from apoptosis induced either by inflammatory cytokines tumor
necrosis factor- + interleukin-1 + interferon- or by prolonged serum withdrawal, and promoted a
significant increase in VSMC proliferation and migration. Of note, all the biological effects induced by TRAIL
were significantly inhibited by pharmacological inhibitors of the ERK pathway. Western blot analysis consistently
showed that TRAIL induced a significant activation of ERK1/2, and a much weaker phosphorylation of Akt, while it
did not affect the p38/MAPK pathway. Taken together, these data strengthen the notion that the TRAIL/TRAIL-R
system likely plays a role in the biology of the vascular system by affecting the survival, migration and
proliferation of VSMCs.Received 6 May 2004; received after revision 7 June 2004; accepted 8 June 2004 相似文献
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Role of full-length osteoprotegerin in tumor cell biology 总被引:1,自引:1,他引:0
G. Zauli E. Melloni S. Capitani P. Secchiero 《Cellular and molecular life sciences : CMLS》2009,66(5):841-851
Osteoprotegerin (OPG) is a soluble tumor necrosis factor receptor family member, which potently inhibits RANKL-mediated osteoclastogenesis.
Numerous constructs have been created for therapeutic purposes in which the heparin-binding and death homology domains of
OPG were removed and the remaining peptide (amino acids 22–194) was fused to the Fc domain of human IgG1 (OPG-Fc). The administration
of OPG-Fc efficiently counteracted bone loss in a variety of preclinical models of cancers. However, several in vitro studies have shown that native or recombinant full-length OPG not only neuralizes RANKL, but also the death-inducing ligand
TRAIL, suggesting that OPG might potentially counteract the anti-tumor activity of TRAIL. Additional evidence suggests that
full-length OPG possesses RANKL- and TRAIL-independent biological properties, mainly related to the promotion of endothelial
cell survival and angiogenesis. Finally, breast tumor cells overexpressing OPG have shown increased bone metastatic potential
in vivo. The relevance of these apparently conflicting findings in tumor cell biology is highlighted.
Received 2 September 2008; received after revision 29 September 2008; accepted 13 October 2008 相似文献
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Stirnimann CU Grütter MG Glockshuber R Capitani G 《Cellular and molecular life sciences : CMLS》2006,63(14):1642-1648
DsbD is a redox-active protein of the inner Escherichia coli membrane possessing an N-terminal (nDsbD) and a C-terminal (cDsbD) periplasmic domain. nDsbD interacts with four different
redox proteins involved in the periplasmic disulfide isomerization and in the cytochrome c maturation systems. We review here the studies that led to the structural characterization of all soluble DsbD domains involved
and, most importantly, of trapped disulfide intermediate complexes of nDsbD with three of its four redox partners. These results
revealed the structural features enabling nDsbD, a ‘redox hub’ with an immunoglobulin-like fold, to interact efficiently with
its different thioredoxin-like partners.
Received 3 February 2006; received after revision 1 March 2006; accepted 5 April 2006 相似文献
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