996 resultados para 1-5A


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为适应在n、γ昆合脉冲辐射场中对低强度快脉冲y辐射测量的需要,近年国内新研制出实用型YAlO3:Ce(YAP:Ce)快响应无机闪烁晶体。我们使用脉冲线性电流大于1.5A的光电倍增管,分别配置这种晶体以及CeF3、NaI等晶体构成闪烁探测器,在放射性标准源场中,对晶体的相对探测能力进行测量。测量结果表明:国产新型YAP:Ce无机晶体对这1.25MeV射线的探测能力比同体积的CeF3平均高一个量级,是同体积NaI的40%左右;当晶体厚度小于2mm时,YAP:Ce与CeF2、NaI的输出比值分别大于16和44%,说明厚度越薄晶体的相对探测能力越强。

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We analyze the mode behaviors for semiconductor lasers with an equilateral triangle resonator by deriving the mode field distribution and the eigenvalue equation. The eigenvalue equation shows that the longitudinal mode wavelength interval is equivalent to that of a Fabry-Perot cavity with the cavity length of 1.5a, where a is the side length of the equilateral triangle resonator. The transverse waveguiding is equivalent to as a strip waveguide with the width of root 3a/ 2, and the number of transverse modes supported by the resonator is limited by the total reflection condition on the sides of the equilateral triangle. Semiconductor microcavity laser with an equilateral triangle resonator is suitable to realize single mode operation, and the mode wavelength can be adjusted by changing the side length.

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The grid altimetry data between 1993 and 2006 near the Philippines were analyzed by the method of Empirical Orthogonal Function (EOF) to study the variation of bifurcation of the North Equatorial Current at the surface of the Pacific. The relatively short-term signals with periods of about 6 months, 4 months, 3 months and 2 months are found besides seasonal and interannual variations mentioned in previous studies. Local wind stress curl plays an important role in controlling variation of bifurcation latitude except in the interannual timescale. The bifurcation latitude is about 13.3A degrees N in annual mean state and it lies at the northernmost position (14.0A degrees N) in January, at the southernmost position (12.5A degrees N) in July. The amplitude of variation of bifurcation latitude in a year is 1.5A degrees, which can mainly be explained as the contributions of the signals with periods of about 1 year (1.2A degrees) and 0.5 year (0.3A degrees).

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The aim of this study was to assess the influence of resin cement insertion methods on the bond strength of a fiber post to root dentin and quality of the cement layer. Forty bovine single-roots (length =16 mm) were randomly allocated into four groups, according to the cement insertion methods (N.=10): Gr1- Lentulo drill #40, Gr2- Centrix syringe, Gr3- Explorer #5, Gr4- fiber post. The root canals were prepared at 12 mm, using preparation bur # 3 of a cylinder quartz-FRC post (Aesthet post-plus, Bisco). The fiber posts were cemented using a multi-step etch-and-rinse adhesive system (All Bond 2®, Bisco) and a dual-cured resin cement (Duolink, Bisco). Each root was cut into seven samples: four samples of 1.8 mm thickness for push-out testing, and three with 0.5 mm for cement layer quality analyzing. One-way ANOVA was used for the push-out test values and the One-Way Kruskal-Wallis (P<0.05) and Dunn (10%) tests for the cement layer analyzes. ANOVA showed that the cement layer quality was affected by the cement insertion methods (P=0.0044): Gr1 (3.8 ± 1.3a), Gr2 (3.2 ± 1.3a), Gr3 (5.2 ± 1.5a,b) and Gr4 (5.2 ± 1.5b) (Dunn test), whereas the bond strength (MPa) was not affected by cement insertion methods: G1 (4.2 ± 1.3), G2 (3.2 ± 1.8), G3 (4.5 ± 0.9), G4 (3.1 ± 1.3). The fiber posts should be cemented with the assistance of the lentulo drill or centrix syringe to promote the best cement layer results.

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Vol. 5 repeated in numbering, with the 2nd v. 5, published in 1965, subsequently designated as v. 5a.

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[EN] The emergent marine deposits of the Mediterranean basin have been recognized as an important record of Quaternary sea level history for more than a century. Previous workers identified what have been interpreted to be two separate high stands of sea in the late Quaternary, namely the "Eutyrrhenian" (thought to be ~ 120 ka) and the "Neotyrrhenian" (thought to be either ~ 100 ka or ~ 80 ka). On Mallorca, Spain, both of these named deposits lie close to present sea level, implying paleo-sea levels slightly above present during both marine isotope stages (MIS) 5.5/5e and either 5.3/5c or 5.1/5a. If these interpretations are correct, they conflict, at least in part, with sea level records from far-field localities.

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Con el objetivo de detectar la prevalencia de signos ecográficos de displasia de cadera en lactantes menores de doce semanas de vida y su asociación con factores de riesgo, se realiza un estudio transversal con 206 lactantes entre seis y doce semanas de vida atendidos en consulta externa del HVCM y que cumplieron con los criterios de inclusión. Se utilizó ecógrafo SONOACE con transductor lineal de 5 MHz y programa incorporado para medición de caderas pediátricas siguiendo la técnica ecográfica combinada de Graft y Harke. Resultados: la prevalencia de signos ecográficos de displasia del desarrollo de la cadera (DDC) fue del 16.0correspondiendo el 14a caderas inestables (tipo Ha), 1.5a caderas subluzadas (tipo Hd) y 0,5a caderas luxadas (tipo III). Al confrontar factores de riesgo se encontró asociación estadística con las variables genralidad p:0.00, prematuridad p:0.00; coexistencia con malformaciones óseas p:0.00 y neurológicas p:0.00; historia familiar DDC p:0.04; ortolam+ p:0.04 y asimetría de pliegues glúteos p:0.00. El resto de variables como sexo femenino, presentación pelviana y otras no mostraron diferencia significativa en el estudio. Discusión: la DDC es una patología multifactorial bastante frecuente en el medio y que puede ser detectada tempranamente mediante valoración ecográfica lo que hasta las doce semanas de vida no se consigue con los estudios radiológicos y que incluso podría pasar inavertida qnte un correcto examen clínico

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Background: Interaction of non-structural protein 5A (NS5A) of Hepatitis C virus (HCV) with human kinases namely, casein kinase 1 alpha (ck1 alpha) and protein kinase R (PKR) have different functional implications such as regulation of viral replication and evasion of interferon induced immune response respectively. Understanding the structural and molecular basis of interactions of the viral protein with two different human kinases can be useful in developing strategies for treatment against HCV. Results: Serine 232 of NS5A is known to be phosphorylated by human ck1 alpha. A structural model of NS5A peptide containing phosphoacceptor residue Serine 232 bound to ck1 alpha has been generated using the known 3-D structures of kinase-peptide complexes. The substrate interacting residues in ck1 alpha has been identified from the model and these are found to be conserved well in the ck1 family. ck1 alpha - substrate peptide complex has also been used to understand the structural basis of association between ck1 alpha and its other viral stress induced substrate, tumour suppressor p53 transactivation domain which has a crystal structure available. Interaction of NS5A with another human kinase PKR is primarily genotype specific. NS5A from genotype 1b has been shown to interact and inhibit PKR whereas NS5A from genotype 2a/3a are unable to bind and inhibit PKR efficiently. This is one of the main reasons for the varied response to interferon therapy in HCV patients across different genotypes. Using PKR crystal structure, sequence alignment and evolutionary trace analysis some of the critical residues responsible for the interaction of NS5A 1b with PKR have been identified. Conclusions: The substrate interacting residues in ck1 alpha have been identified using the structural model of kinase substrate peptide. The PKR interacting NS5A 1b residues have also been predicted using PKR crystal structure, NS5A sequence analysis along with known experimental results. Functional significance and nature of interaction of interferon sensitivity determining region and variable region 3 of NS5A in different genotypes with PKR which was experimentally shown are also supported by the findings of evolutionary trace analysis. Designing inhibitors to prevent this interaction could enable the HCV genotype 1 infected patients respond well to interferon therapy.