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排序方式: 共有86条查询结果,搜索用时 171 毫秒
31.
32.
MK Bhide RM Kadam MD Sastry Ajay Singh Shashwati Sen Manmeet Kaur DK Aswal SK Gupta VC Sahni 《Pramana》2002,58(5-6):799-802
Microwave absorption studies have been carried out on MgB2 superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for
polycrystalline (grain size ∼ 10 μm) samples suggested the absence of weak-link character. The field dependent direct microwave
absorption has been found to obey a ✓H dependence with two different slopes, which indicated a transition from strongly pinned lattice to flux flow regime. 相似文献
33.
A.D. Bacher G.T. Emery W.P. Jones D.W. Miller G.S. Adams F. Petrovich W.G. Love 《Physics letters. [Part B]》1980,97(1):58-62
Differential cross sections for the excitation of states at 6.42, 6.73 and 7.04 MeV in 208Pb by 135 MeV protons are reported. Both the excitation energies and the backward peaked angular distributions observed in this experiment and in a recent (e, e′) experiment strongly suggest that these states are predominantly one-particle-one-hole excitations with Jπ = 12?, 14? and 12?, respectively. The present (p, p′) data are interpreted using a distorted wave impluse approximation and the effect of configuration mixing between the two 12? states is investigated. 相似文献
34.
35.
A. Yu. Petrovich 《Mathematical Notes》1974,16(4):975-982
36.
Alexander Vladimirovich Ivanov Edward Danielevich Virus Ksenya Alexandrovna Nikiforova Nicolai Evgenevich Kushlinskii Boris Petrovich Luzyanin Marina Yurievna Maksimova Mikhail Aleksanrovich Piradov Aslan Amirkhanovich Kubatiev 《Electrophoresis》2016,37(20):2663-2669
An approach that allows direct analysis of the ratio of S‐adenosylmethionine (SAM) and S‐adenosylhomocysteine (SAH) by using CE is presented. The analytes were extracted on phenylboronic acid phase and eluted with 100 mmol/L HCl. CE separation of the analytes took place in the transient isotachophoresis mode with addition of NaCl and meglumine to the samples. The sensitivity (S/N = 3) and quantification limit (S/N = 10) of the method were 0.07 and 0.2 μmol/L, respectively, using a silica capillary with 50 μm internal diameter and 30.5 cm total length. The BGE was 0.02 mol/L Tris with 1 mol/L HCOOH (pH 2.2), and the separation voltage was 15–17 kV. Accuracy of SAM and SAH analysis in urine was 96 and 105%, respectively; interday precision for the SAM/SAH ratio was within 6%. The theoretical plate number exceeded a million. Total analysis time was 8.5 min. 相似文献
37.
An alternative notion of an existential quantifier on four-valued ?ukasiewicz algebras is introduced. The class of four-valued ?ukasiewicz algebras endowed with this existential quantifier determines a variety which is denoted by \(\mathbb {M}_{\frac{2}{3}}\mathbb {L}_4\). It is shown that the alternative existential quantifier is interdefinable with the standard existential quantifier on a four-valued ?ukasiewicz algebra. Some connections between the new existential quantifier and the existential quantifiers defined on bounded distributive lattices and Boolean algebras are given. Finally, a completeness theorem for the monadic four-valued ?ukasiewicz predicate calculus corresponding to the dual of the alternative existential quantifier is proven. 相似文献
38.
Deterding LJ Williams JG Humble MM Petrovich RM Wei SJ Trempus CS Gates MB Zhu F Smart RC Tennant RW Tomer KB 《International journal of mass spectrometry》2011,301(1-3):12-21
CD34, a type I transmembrane glycoprotein, is a surface antigen which is expressed on several cell types, including hematopoietic progenitors, endothelial cells, as well as mast cells. Recently, CD34 has been described as a marker for epidermal stem cells in mouse hair follicles, and is expressed in outer root sheath cells of the human hair follicle. Although the biological function and regulation of CD34 is not well understood, it is thought to be involved in cell adhesion as well as possibly having a role in signal transduction. In addition, CD34 was shown to be critical for skin tumor development in mice, although the exact mechanism remains unknown.Many proteins' functions and biological activities are regulated through post-translational modifications. The extracellular domain of CD34 is heavily glycosylated but the role of these glycans in CD34 function is unknown. Additionally, two sites of tyrosine phosphorylation have been reported on human CD34 and it is known that CD34 is phosphorylated, at least in part, by protein kinase C; however, the precise location of the sites of phosphorylation has not been reported. In an effort to identify specific phosphorylation sites in CD34 and delineate the possible role of protein kinase C, we undertook the identification of the in vitro sites of phosphorylation on the intracellular domain of mouse CD34 (aa 309-382) following PKC treatment. For this work, we are using a combination of enzymatic proteolysis and peptide sequencing by mass spectrometry. After which the in vivo sites of phosphorylation of full-length mouse CD34 expressed from HEK293F cells were determined. The observed in vivo sites of phosphorylation, however, are not consensus PKC sites, but our data indicate that one of these sites may possibly be phosphorylated by AKT2. These results suggest that other kinases, as well as PKC, may have important signaling functions in CD34. 相似文献
39.
The brain is believed to be particularly vulnerable to arsenic due to its high oxygen consumption rate and high level of polyunsaturated fatty acids and relatively high rate of oxygen free radical generate without commensurable level of arsenic. Hence, in the present work an attempt is made to study the changes in the biochemical contents in the brain tissues of edible fish Labeo rohita due to arsenic intoxication using Fourier Transform Infrared (FT-IR) spectroscopy. FT-IR spectra reveal significant differences in absorbance intensities between the control and arsenic intoxicated brain tissues, reflecting an alteration on the major biochemical constituents, such as lipids, proteins and nucleic acids of the brain tissues of L. rohita due to arsenic intoxication. Further, the administration of antidote DMSA improves the protein and lipid contents significantly in the brain tissues when compared to arsenic intoxicated tissues. The decrease in α-helix structure due to arsenic intoxication might be responsible for the increase in β-sheet secondary structures, which is consistent with the mechanism of β-sheet formation. 相似文献
40.
A.?AndrighettoEmail author S.?Cevolani C.?Petrovich 《The European Physical Journal A - Hadrons and Nuclei》2005,25(1):41-47
A possible solution for a target system aimed at the production of exotic nuclei as a result of high-energy fissions in 238U compounds has been analyzed. The configuration proposed is constituted by a primary proton beam (40 MeV, 0.4 mA) directly impinging on a UC2 multiple-disc target inserted within a cylindrical tungsten box. In order to extract the fission fragments, the tungsten box has to be kept at 2000 °C. This system has been conceived to obtain both a high number of fission fragments (about 2 . 1013 atoms/s) and a quite low power deposition in the target. The power release and the fragment distribution have been calculated by means of the Monte Carlo code MCNPX. The thermal analysis of the proposed configuration shows the capability of the thermal radiation to cool the discs with a reasonable margin below the material melting point. Moreover, the possibility of increasing such margin with simple modifications of the target design is shown by means of parametric analyses. The thermal analysis of the tungsten box, also cooled by radiation, points out the necessity to heat it and/or shield it thermally, in order to take it at the requested temperature. Preliminary calculations of the target-induced activity have also been performed. 相似文献