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71.
A. Bećarević K. Kaćanski D. Mančić Ljiljana Hadžić 《Cellular and molecular life sciences : CMLS》1956,12(1):23-24
Summary In the rat, X-irradiation leads to a decrease of the net RNA and DNA content of the spleen, without, however, increasing the low molecular weight nucleic acid derivatives in the acid-soluble fractions of the same tissue. It is suggested that an alteration of the cell membranes could account for the apparent elimination of these nucleic acid degradation products which should normally appear in the acid-soluble fraction. 相似文献
72.
Spatially resolved electronic structure inside and outside the vortex cores of a high-temperature superconductor 总被引:1,自引:0,他引:1
Mitrović VF Sigmund EE Eschrig M Bachman HN Halperin WP Reyes AP Kuhns P Moulton WG 《Nature》2001,413(6855):501-504
Puzzling aspects of high-transition-temperature (high-Tc) superconductors include the prevalence of magnetism in the normal state and the persistence of superconductivity in high magnetic fields. Superconductivity and magnetism generally are thought to be incompatible, based on what is known about conventional superconductors. Recent results, however, indicate that antiferromagnetism can appear in the superconducting state of a high-Tc superconductor in the presence of an applied magnetic field. Magnetic fields penetrate a superconductor in the form of quantized flux lines, each of which represents a vortex of supercurrents. Superconductivity is suppressed in the core of the vortex and it has been suggested that antiferromagnetism might develop there. Here we report the results of a high-field nuclear-magnetic-resonance (NMR) imaging experiment in which we spatially resolve the electronic structure of near-optimally doped YBa2Cu3O7-delta inside and outside vortex cores. Outside the cores, we find strong antiferromagnetic fluctuations, whereas inside we detect electronic states that are rather different from those found in conventional superconductors. 相似文献
73.
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75.
Irena Crnković-Mertens Julia Bulkescher Christina Mensger Felix Hoppe-Seyler Karin Hoppe-Seyler 《Cellular and molecular life sciences : CMLS》2010,67(11):1895-1905
Livin (ML-IAP) is a cancer-associated member of the inhibitor of apoptosis protein (IAP) family. By yeast two-hybrid screening
of a randomized peptide expression library, we isolated short linear peptides that specifically bind to Livin, but not to
other IAPs. Intracellular expression of the peptides sensitized livin-expressing cancer cells toward different pro-apoptotic stimuli. The bioactive peptides neither showed sequence homologies
to Smac-derived IAP inhibitors, nor did they interfere with the binding of Livin to Smac. Intracellular expression of the
peptides did not affect the levels or the subcellular distribution of Livin. Growth of livin-expressing tumor cells was inhibited in colony formation assays by the Livin-targeting peptides. These findings provide evidence
that the targeted inhibition of Livin by peptides represents a viable approach for the apoptotic sensitization and growth
inhibition of tumor cells. The inhibitory peptides isolated here could form a novel basis for the development of therapeutically
useful Livin inhibitors. 相似文献
76.
V. M. Petrović M. Spasić Z. Saičić B. Milić R. Radojičić 《Cellular and molecular life sciences : CMLS》1982,38(11):1355-1356
Summary The activity of cytoplasmic superoxide dismutase (SOD) in the liver was about twice as high in adult rats as it was in neonates. In the brain and in the interscapular brown adipose tissue (IBAT), SOD activity was not changed during postnatal development, although it was slightly higher in the brain than in the IBAT (p>0.1). Thyroid hormones produced an increase in SOD activity in the brain of newborn rats, as well as in those animals 30 and 60 days old. The same quantity of hormones did not produce any significant changes in the liver or in the IBAT. 相似文献
77.
Evidence of diurnal fluctuation of sensitivity to noradrenaline in the rat — the role of the thyroid
V. M. Petrović Katica Maksimović Leposava Marković-Giaja 《Cellular and molecular life sciences : CMLS》1976,32(12):1544-1545
Summary The capacity for heat production, under the influence of the same amount of noradrenaline, in the rat was significantly higher in the evening (20.00 h) than in the morning (07.00 h). Thyroidectomy produces not only a lower level of heat production, but also a complete disappearance of the differences between the morning and the evening experiments. 相似文献
78.
Xenopsin stimulates exocrine pancreatic secretion in the dog 总被引:1,自引:0,他引:1
G. E. Feurle I. Baća W. Knauf A. Schwab T. Araki R. Carraway 《Cellular and molecular life sciences : CMLS》1982,38(6):679-680
Summary The octapeptide xenopsin, previously isolated from amphibian skin, stimulates exocrine pancreatic secretion of bicarbonate and protein in conscious dogs and increases the volume of secretion. This effect is shown in the dose range of 1.25 up to 160 pmoles kg–1min–1 The high potency of this peptide is suggestive of a possible physiological role of xenopsin in mammals.This work was supported by the Deutsche Forschungsgemeinschaft Fe 127/4. 相似文献
79.
Vesna Nikoli? ?eljko Kamberovi? Zoran An?i? Marija Kora? Miroslav Soki? Vesna Maksimovi? 《矿物冶金与材料学报》2014,21(8):806-812
A method of synthesizing Ni-based catalysts supported on α-Al2O3-based foams was developed. The foams were impregnated with aqueous solutions of metal chlorides under an air atmosphere using an aerosol route. Separate procedures involved calcination to form oxides and drying to obtain chlorides on the foam surface. The synthesized samples were subsequently reduced with hydrogen. With respect to the Ni/Al2O3 catalysts, the chloride reduction route enabled the formation of a Ni coating without agglomerates or cracks. Further research included catalyst modification by the addition of Pd, Cu, and Fe. The influences of the additives on the degree of reduction and on the low-temperature reduction effectiveness (533 and 633 K) were examined and compared for the catalysts obtained from oxides and chlorides. Greater degrees of reduction were achieved with chlorides, whereas Pd was the most effective modifier among those investigated. The reduction process was nearly complete at 533 K in the sample that contained 0.1wt% Pd. A lower reduction temperature was utilized, and the calcination step was avoided, which may enhance the economical and technological aspects of the developed catalyst production method. 相似文献
80.
Chen J Badioli M Alonso-González P Thongrattanasiri S Huth F Osmond J Spasenović M Centeno A Pesquera A Godignon P Elorza AZ Camara N García de Abajo FJ Hillenbrand R Koppens FH 《Nature》2012,487(7405):77-81
The ability to manipulate optical fields and the energy flow of light is central to modern information and communication technologies, as well as quantum information processing schemes. However, because photons do not possess charge, a way of controlling them efficiently by electrical means has so far proved elusive. A promising way to achieve electric control of light could be through plasmon polaritons—coupled excitations of photons and charge carriers—in graphene. In this two-dimensional sheet of carbon atoms, it is expected that plasmon polaritons and their associated optical fields can readily be tuned electrically by varying the graphene carrier density. Although evidence of optical graphene plasmon resonances has recently been obtained spectroscopically, no experiments so far have directly resolved propagating plasmons in real space. Here we launch and detect propagating optical plasmons in tapered graphene nanostructures using near-field scattering microscopy with infrared excitation light. We provide real-space images of plasmon fields, and find that the extracted plasmon wavelength is very short—more than 40 times smaller than the wavelength of illumination. We exploit this strong optical field confinement to turn a graphene nanostructure into a tunable resonant plasmonic cavity with extremely small mode volume. The cavity resonance is controlled in situ by gating the graphene, and in particular, complete switching on and off of the plasmon modes is demonstrated, thus paving the way towards graphene-based optical transistors. This successful alliance between nanoelectronics and nano-optics enables the development of active subwavelength-scale optics and a plethora of nano-optoelectronic devices and functionalities, such as tunable metamaterials, nanoscale optical processing, and strongly enhanced light–matter interactions for quantum devices and biosensing applications. 相似文献