998 resultados para (900 1170) °C


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Single-stranded DNA binding protein (Ssb) of Deinococcus radiodurans comprises N- and C-terminal oligonucleotide/oligosaccharide binding (OB) folds connected by a beta hairpin connector. To assign functional roles to the individual OB folds, we generated three Ssb variants: Ssb(N) (N-terminal without connector), Ssb(NC) (N-terminal with connector) and Ssb(C) (C-terminal), each harboring one OB fold. Both Ssb(N) and Ssb(NC) displayed weak single-stranded DNA (ssDNA) binding activity, compared to the full-length Ssb (Ssb(FL)). The level of ssDNA binding activity displayed by SsbC was intermediate between Ssb(FL) and Ssb(N). Ssb(C) and Ssb(FL) predominantly existed as homo-dimers while Ssb(NC)/Ssb(N) formed different oligomeric forms. In vitro, Ssb(NC) or Ssb(N) formed a binary complex with Ssb(C) that displayed enhanced ssDNA binding activity. Unlike Ssb(FL), Ssb variants were able to differentially modulate topoisomerase-I activity, but failed to stimulate Deinococcal RecA-promoted DNA strand exchange. The results suggest that the C-terminal OB fold is primarily responsible for ssDNA binding. The N-terminal OB fold binds weakly to ssDNA but is involved in multimerization. (C) 2015 The Authors. Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies. This is an open access article under the CC BY-NC-ND license.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The hot deformation behavior of Nb-1 wt.%Zr alloy was studied using uniaxial compression tests carried out in vacuum to a true strain of 0.6 in the temperature range of 900 to 1700 degrees C and the strain rate range of 3 x 10(-3) to 10 s(-1). The optimum regime of hot workability of Nb-1Zr alloy was determined from the strain rate sensitivity (m) contour plots. A high m of about 02 was obtained in the temperature and strain rate range of 1200-1500 degrees C and 10(-3) to 10(-1) s(-1) and 1600-1700 degrees C and 10(-1) to 1 s(-1). Microstructure of the deformed samples showed features of dynamic recrystallization within the high strain rate sensitivity domain. Compared to the study on Nb-1Zr-0.1C alloy, Nb-1Zr showed a lower flow stress and an optimum hot working domain at lower temperatures. In the 1500 to 1700 degrees C range the apparent activation energy of deformation for Nb-1Zr was 259 kJ mol(-1), the stress exponent 5, and the activation volume about 200 to 700 b(3). (C) 2015 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this article, we propose a C-0 interior penalty ((CIP)-I-0) method for the frictional plate contact problem and derive both a priori and a posteriori error estimates. We derive an abstract error estimate in the energy norm without additional regularity assumption on the exact solution. The a priori error estimate is of optimal order whenever the solution is regular. Further, we derive a reliable and efficient a posteriori error estimator. Numerical experiments are presented to illustrate the theoretical results. (c) 2015Wiley Periodicals, Inc.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Non-covalent halogen-bonding interactions between n cloud of acetylene (C2H2) and chlorine atom of carbon tetrachloride (CCl4) have been investigated using matrix isolation infrared spectroscopy and quantum chemical computations. The structure and the energies of the 1:1 C2H2-CCl4 adducts were computed at the B3LYP, MP2 and M05-2X levels of theory using 6-311++G(d,p) basis set. The computations indicated two minima for the 1:1 C2H2-CCl4 adducts; with the C-Cl center dot center dot center dot pi adduct being the global minimum, where pi cloud of C2H2 is the electron donor. The second minimum corresponded to a C-H...Cl adduct, in which C2H2 is the proton donor. The interaction energies for the adducts A and B were found to be nearly identical. Experimentally, both C-Cl center dot center dot center dot pi and C-H center dot center dot center dot Cl adducts were generated in Ar and N2 matrixes and characterized using infrared spectroscopy. This is the first report on halogen bonded adduct, stabilized through C-Cl center dot center dot center dot pi interaction being identified at low temperatures using matrix isolation infrared spectroscopy. Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) analyses were performed to support the experimental results. The structures of 2:1 ((C2H2)(2)-CCl4) and 1:2 (C2H2-(CCl4)(2)) multimers and their identification in the low temperature matrixes were also discussed. (C) 2015 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Using a recently proposed Ginzburg-Landau-like lattice free energy functional due to Banerjee et al. (2011) we calculate the fluctuation diamagnetism of high -T-c superconductors as a function of doping, magnetic field and temperature. We analyse the pairing fluctuations above the superconducting transition temperature in the cuprates, ranging from the strong phase fluctuation dominated underdoped limit to the more conventional amplitude fluctuation dominated overdoped regime. We show that a model where the pairing scale increases and the superfluid density decreases with underdoping produces features of the observed magnetization in the pseudogap region, in good qualitative and reasonable quantitative agreement with the experimental data. In particular, we explicitly show that even when the pseudogap has a pairing origin the magnetization actually tracks the superconducting dome instead of the pseudogap temperature, as seen in experiment. We discuss the doping dependence of the `onset' temperature for fluctuation diamagnetism and comment on the role of vortex core -energy jn our model. (C) 2015 Elsevier Inc. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this study, the influence of the spatial and temporal variability of upwelling intensity and the associated biological productivity observed during different phases of summer monsoon along the southwestern continental margin of India (SWCMI) on the delta C-13 and delta O-18 of the inorganic biogenic carbonate shells was investigated. Multispecies benthic bivalve shells (1-5 mm) separated from ten surface sediment samples of SWCMI (off 12 degrees N, 10 degrees N and 9 degrees N) collected during the onset (OSM) and peak (PSM) phase of the summer monsoon of 2009 were analysed for delta C-13 and delta O-18. Sea surface temperature along the study region indicates prominent upwelling in PSM than in OSM. A comparison of analytical and predicted values for delta O-18 in the bivalve shells confirmed their in situ origin during both the sampling periods. During PSM, the delta C-13 values in the benthic bivalve shells were more depleted in C-13 than during OSM which recorded lower values of delta C-13 in dissolved inorganic carbon of bottom waters expected in the study region in PSM due to the upwelled waters, high surface productivity and the associated high degradation of the organic matter in the subsurface and bottom waters. However, this depletion of delta C-13 was not observed in benthic bivalve shells obtained from 10 degrees N, since it is influenced by high export fluxes of carbon from the Cochin estuary since early monsoon months.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Chronic hepatitis C virus (HCV) infection represents a major health threat to global population. In India, approximately 15-20% of cases of chronic liver diseases are caused by HCV infection. Although, new drug treatments hold great promise for HCV eradication in infected individuals, the treatments are highly expensive. A vaccine for preventing or treating HCV infection would be of great value, particularly in developing countries. Several preclinical trials of virus-like particle (VLP) based vaccine strategies are in progress throughout the world. Previously, using baculovirus based system, we have reported the production of hepatitis C virus-like particles (HCV-LPs) encoding structural proteins for genotype 3a, which is prevalent in India. In the present study, we have generated HCV-LPs using adenovirus based system and tried different immunization strategies by using combinations of both kinds of HCV-LPs with other genotype 3a-based immunogens. HCV-LPs and peptides based ELISAs were used to evaluate antibody responses generated by these combinations. Cell-mediated immune responses were measured by using T-cell proliferation assay and intracellular cytokine staining. We observed that administration of recombinant adenoviruses expressing HCV structural proteins as final booster enhances both antibody as well as T-cell responses. Additionally, reduction of binding of VLP and JFH1 virus to human hepatocellular carcinoma cells demonstrated the presence of neutralizing antibodies in immunized sera. Taken together, our results suggest that the combined regimen of VLP followed by recombinant adenovirus could more effectively inhibit HCV infection, endorsing the novel vaccine strategy. (C) 2015 Elsevier Ltd. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The laser-solidified microstructural and compositional characterization and phase evolution during tempering at 963 K were investigated using an analytical transmission electron microscope with energy dispersive X-ray analysis. The cladded alloy, a powder mixture of Fe, Cr, W, Ni, and C with a weight ratio of 10:5:1:1:1, was processed with a 3 kW continuous wave CO2 laser. The processing parameters were 16 mm/s beam scanning speed, 3 mm beam diameter. 2 kW laser power, and 0.3 g/s feed rate. The coating was metallurgically bonded to the substrate, with a maximum thickness of 730 mu m, a microhardness of about 860 Hv and a volumetric dilution ratio of about 6%. Microanalyses revealed that the cladded coating possessed the hypoeutectic microstructure comprising the primary dendritic gamma-austenite and interdendritic eutectic consisted of gamma-austenite and M7C3 carbide. The gamma-austenite was a non-equilibrium phase with extended solid solution of alloying elements and a great deal of defect structures, i.e. a high density of dislocations, twins, and stacking faults existed in gamma phase. During high temperature aging, in situ carbide transformation occurred of M7C3 to M23C6 and M6C. The precipitation of M23C6, MC and M2C carbides from austenite was also observed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

El presente trabajo tuvo, como objetivo evaluar en trminos biolgicos y econmicos, el efecto de la implementacin de 3 mtodos de cosecha, (Cosecha normal, cosecha escalonada y recoleccin del suelo), para la evaluacin de produccin y calidad en semilla de Brachiaria brizantha CIAT 6780 cv Marand. Este se llev acabo en el km.14 de la carretera norte, 2 km. al sur, en el Instituto Nacional de Investigacin Agropecuaria (INTA)-(CNIA). El anlisis de calidad de la semilla se realiz, empleando la metodologa utilizada por el CIAT, para el anlisis de calidad de semillas brozosas (con gran cantidad de residuos de inflorescencias). Se utiliz un diseo de bloque completo al azar con tres mtodos de cosecha como tratamiento y tres repeticiones por tratamiento. Los resultados demuestran que los mtodos de cosecha tuvieron efectos estadsticamente significativos (P<0.01) sobre el rendimiento de semilla cruda y semilla pura por hectrea. El incremento en el rendimiento de semilla cruda estuvo influenciado por la mayor cantidad de material inerte contenido en la muestra del tratamiento tres (Recoleccin del suelo) similar comportamiento presentaron los componentes estructurales longitud del raquiz, longitud del raquisillo, nmero de raquisillo y espiguillas por raquisillo (promedio). En el caso de los componentes estructurales nmero de plantas y nmero de espiguillas por raquisillo no hubo diferencias de efectos sobre el rendimiento. Para el anlisis estadstico de las variables de calidad en la semilla, se realiz la prueba de Duncan para las diferencias de proporciones. El porcentaje de semilla pura present su mximo de valor con el mtodo de cosecha normal aplicado como tratamiento uno. Para el porcentaje de viabilidad el valor ms alto result con el mtodo de barrido o recoleccin del suelo aplicado como tratamiento tres, estos resultados coinciden con lo reportado por el CIAT 1980; Garca y Ferguson, 1984 comparan la eficiencia relativa de los diferentes mtodos de cosecha, en la cual la recoleccin de semilla cada ofrece el mayor porcentaje de germinacin. De todos los tratamientos evaluados, el mximo beneficio monetario se obtuvo con la implementacin del mtodo de cosecha escalonado (US$565/ha). Sin embargo la cosecha normal fue el tratamiento con el que se obtuvo el mayor margen de ingreso bruto (83% del ingreso total), en comparacin a los otros dos mtodos de cosecha aplicados como tratamiento.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Numerical simulation of an oil slick spreading on still and wavy surfaces is described in this paper. The so-called sigma transformation is used to transform the time-varying physical domain into a fixed calculation domain for the water wave motions and, at the same time, the continuity equation is changed into an advection equation of wave elevation. This evolution equation is discretized by the forward time and central space scheme, and the momentum equations by the projection method. A damping zone is set up in front of the outlet boundary coupled with a Sommerfeld-Orlanski condition at that boundary to minimize the wave reflection. The equations for the oil slick are depth-averaged and coupled with the water motions when solving numerically. As examples, sinusoidal and solitary water waves, the oil spread on a smooth plane and on still and wavy water surfaces are calculated to examine the accuracy of simulating water waves by Navier-Stokes equations, the effect of damping zone on wave reflection and the precise structures of oil spread on waves.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Con el objetivo de determinar la influencia de dos rotaciones y tres mtodos de control de malezas sobre el crecimiento, desarrollo y rendimiento de la soya se realiz un estudio en los terrenos de la Hacienda "Las Mercedes" en Managua, sobre un suelo de textura arcillosa. La siembra se realiz el siete de septiembre de 1990, utilizando un diseo en bloques completos al azar en parcelas divididas con cuatro rplicas. Siendo el factor "A": rotacin; a3 = maz, a4 = pepino; y el factor "B": Mtodos de control de malezas; b1 = qumico, b2 = perodo crtico, b3=limpia peridica. Los resultados reflejan que el cultivo antecedente maz representa menor abundancia, cobertura y biomasa de malezas a la cosecha de la soya, siendo la especie ms abundante Rottboellia cochinchinensis. El cultivo antecedente pepino presenta la menor diversidad, con mayor abundancia de la especie R. cochinchinensis seguida de Cyperus rotundus. Se obtuvieron diferencias significativas solamente en altura de planta a los 27 y 42 das despus de la siembra a favor del cultivo antecedente maz, tambin se obtuvo mayor nmero de plantas 39.4 pta/m2, altura de plantas 63.9 cm, nmero de vainas por plantas 13.92, nmero de ramas por planta 1.4, dimetro del tallo 3.98 mm, peso seco de paja 4824.5 kg/ha y rendimiento de grano 2289.42 kg/ha. Respecto a los mtodos de control la menor abundancia, cobertura y biomasa de malezas se present en limpia peridica y el mayor valor el control qumico fomesafn en post-emergencia. La diversidad al momento de la cosecha fue similar en los controles limpia peridica y perodo crtico. Las variables de crecimiento, desarrollo y rendimiento presentaron diferencias significativas para altura de plantas 67.3 cm a favor del control qumico; nmero de semillas por vaina 2.80 a favor de periodo crtico; nmero de ndulos por planta en R5 14.25, nmero de ramas por planta 2.4, nmero de vainas 24.75, dimetro del tallo 5.0 mm, peso seco de paja 7645.8 kg/ha, peso de 1000 semillas 153 g y rendimiento del grano 4141.5 kg/ha a favor del control limpia peridica. En el control qumico se present el menor nmero de semillas por vaina 2.55, vainas por planta 5.5, peso seco de ndulos: R1=0.15 g/pta y R5=0.34 g/pta y rendimiento con 832 kg/ha.