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排序方式: 共有1112条查询结果,搜索用时 15 毫秒
91.
92.
I Kohno H Iwasaki M Okutani Y Mochizuki S Sano Y Satoh T Ishihara H Ishii S Mukaiyama H Ijiri S Komori K Tamura 《Canadian Metallurgical Quarterly》1997,14(1):71-84
Cells of the central nervous system (CNS) normally do not express detectable levels of major histocompatibility complex (MHC) Class I antigens. However, MHC Class I expression can be induced after virus infection. We tested the hypothesis that virus-induced Class I expression is mediated by lymphocytes or cytokines using lymphocyte- and cytokine-deficient mice. We used Theiler's murine encephalomyelitis virus (TMEV), which induces CNS demyelination that maps genetically to the D region of MHC Class I and is associated with high levels of Class I products. TMEV infection of severe combined immunodeficiency (SCID) and recombination activation gene-1-deficient mice, which lack B and T lymphocytes, resulted in equivalent H-2D and H-2K expression in brain and spinal cord, according to analysis of the area and intensity of immunoperoxidase staining. Class I antigens were demonstrated as early as 6 hours after infection, and they were more widely distributed than viral RNA, indicating that expression was induced indirectly via a soluble factor. To determine whether cytokines induced the expression, we infected mice lacking receptors for interferon-alpha/beta (IFN-alpha/beta R (-/-)), interferon-gamma (IFN-gamma R(-/-)), and tumor necrosis factor-alpha (TNFRp55(-/-)). TMEV-infected IFN-gamma R(-/-) and TN-FRp55(-/-) mice expressed Class I antigens in the CNS, whereas IFN-alpha/beta R(-/-) mice did not, establishing that IFN-alpha/beta mediated the expression. In contrast to the equivalent expression in SCID mice, we observed greater area and higher intensity of H-2D versus H-2K antigens in infected SCID mice reconstituted with normal spleen cells. Collectively, the data indicate that after TMEV infection, early generalized MHC Class I expression is mediated by IFN-alpha/beta independently of lymphocytes, but the differential regulation of H-2D over H-2K may be controlled by B and/or T lymphocytes. 相似文献
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Enhancing effect of monoolein surfactant on carbon nanoparticle synthesis by arc discharge in liquid
Tawatchai Charinpanitkul Noriaki Sano Poonlasak Muthakarn 《Materials Research Bulletin》2009,44(2):324-917
Effect of monoolein surfactant which promotes n-hexane to dissolve in water was investigated to enhance the carbon nanoparticle (CNP) synthesis by arc discharge in liquid. The production rate of CNPs consisting of multi-shelled fullerenes and multi-walled carbon nanotubes was increased by the addition of the n-hexane to water with support of monoolein surfactant. An optimal amount of monoolein led to the maximal production rate of CNPs which was ca. two-fold higher than that obtained from a pure water system. This effect is ascribed to the role of n-hexane and monoolein to provide carbon clusters to the arc reactive zone. The hydrodynamic particle sizes of CNPs and their crystallinity were also enhanced by the addition of these organic compounds. As the vapor pressure of the organic component is significantly suppressed, the proposed method is much safer than that using pure organic liquid. 相似文献
96.
97.
Nosaka H. Sano E. Ishii K. Ida M. Kurishima K. Yamahata S. Shibata T. Fukuyama H. Yoneyama M. Enoki T. Muraguchi M. 《Solid-State Circuits, IEEE Journal of》2004,39(8):1361-1365
We describe a 40-Gbit/s-class clock and data recovery (CDR) circuit with an extremely wide pull-in range. A Darlington-type voltage-controlled oscillator (VCO) is newly designed to cover the STM-256/OC-768 full-rate-clock frequencies with a wide frequency margin. We also describe a new lock detector using an exclusive-NOR gate. The CDR IC was fabricated using InP/InGaAs HBTs. Error-free operation and wide eye opening were confirmed for 40-, 43-, and 45-Gbit/s PRBS with a word length of 2/sup 31/ - 1. We attached a frequency search and phase control (FSPC) circuit to the chip as a new frequency acquisition aid, and this allows the CDR circuit to pull in throughout a 39-45-Gbit/s range. The peak-to-peak and rms jitter of the recovered clock were 3.6 and 0.48 ps, respectively. 相似文献
98.
A Kobayashi K Mori M Konishi K Maeda K Mikasa T Yoneda N Narita R Sano T Masutani 《Canadian Metallurgical Quarterly》1998,72(10):1070-1075
Achromobacter xylosoxidans is a gram-negative bacterium whose natural habitat has not been clearly defined. It has been isolated from ear discharge and the large intestine of humans and from various hospital or environmental water sources. Infection with A. xylosoxidans in humans has been documented, and resulting illnesses include meningitis, pneumonia, cholecystitis, peritonitis and urinary tract infection. Bacteremia due to A. xylosoxidans is rare, and little information on treatment is available. Two cases of bacteremia due to A. xylosoxidans in patients with hemapoietic malignancies are reported herein. Case 1 involved a 70-yr. male whose clinical diagnosis was IgA lambda-type plasmacytoma. Case 2 involved 72-yr. male whose clinical diagnosis was acute lymphatic leukemia (L2). Both patients had been catheterized. Neutropenia was noted and the white blood cell counts were 20/microliter in case 1 and 35/microliter in case 2 when A. xylosoxidans was isolated from the blood culture. We suggest that bacteremia due to A. xylosoxidans may have been related to the presence of the catheter and neutropenia. 相似文献
99.
H Kino H Inaba N Van De L Van Chau DT Son HT Hao ND Toan LD Cong M Sano 《Canadian Metallurgical Quarterly》1998,29(2):250-254
We present the spatial structure of binase, a small extracellular ribonuclease, derived from 1H-NMR* data in aqueous solution. The total of 20 structures were obtained via torsion angle dynamics using DYANA program with experimental NOE and hydrogen bond distance constraints and phi and chi1 dihedral angle constraints. The final structures were energy minimised with ECEPP/2 potential in FANTOM program. Binase consists of three alpha-helices in N-terminal part (residues 6-16, 26-32 and 41-44), five-stranded antiparallel beta-sheet in C-terminal part (residues 51-55, 70-75, 86-90, 94-99 and 104-108) and two-stranded parallel beta-sheet (residues 22-24 and 49-51). Three loops (residues 36-39, 56-67 and 76-83), which play significant role in biological functioning of binase, are flexible in solution. The differences between binase and barnase spatial structures in solution explain the differences in thermostability of binase, barnase and their hybrids. 相似文献
100.
K Ikeda R Nagai T Sakamoto H Sano T Araki N Sakata H Nakayama M Yoshida S Ueda S Horiuchi 《Canadian Metallurgical Quarterly》1998,215(1-2):95-104
An extractionless method for determining aflatoxin M1 (AFM1), a major metabolite of aflatoxin B1 (AFB1), in human urine was developed. The biological fluid is injected directly into the chromatographic system after simple dilution and centrifugation. A pre-column, packed with a cation-exchange phase and coupled on-line to a column-switching liquid chromatography (LC) system, is used for sample pre-treatment and concentration. The analytes are non-selectively desorbed with the LC eluent and cleaned by means of a column-switching procedure. Pre-treatment and analysis were performed within 40 min. Average AFMI recovery reached 97% in the 10-100 ng/l range of urine. The detection limit of AFM1 in urine and milk was 2.5 ng/l for 1 ml of injected sample. A comparison with an immunoaffinity column clean-up and LC method was performed. The method was applied to determine AFM1 in the urine of AFB1 gavaged rats, and in the urine of both potentially exposed and supposedly unexposed workers. The method was also extended to milk. 相似文献