1,197 research outputs found
Cloning and expression of a Saccharomyces cerevisiae RNA-dependent RNA polymerase
RNA-dependent RNA polymerases (RdRp) are ubiquous enzimes first described in RNA viruses and virus-like elements. In Saccharomyces cerevisiae this enzyme can be found, fused with capsid proteins, encoded by the L-A helper virus-like particle. Replication cycle of L-A is coupled to that of M satellite particle, which confers a killer phenotype to the yeast (Schmitt & Breinig, 2002). RdRp recognizes and replicates ssRNA from both L-A and M virus. RdRp recognizes a 3'-Terminal Recognition Element (3'TRE), a small stem-loop 5 bases from the 3' end (Ribas, Fujimuras, & Wickner, 1994), which can be used as an effective tool for primerless replication of RNA molecules. To gain further insight on the virus-like particle replication mechanism and to evaluate its possible biotechnological application, the present project is focused on cloning the RdRp coding sequence in several different expression vectors and expressing the protein using different Escherichia coli strains as hosts. Once RdRp is efficiently expressed, we will proceed to purify it by affinity chromatography and test the protein activity by replicating full length viral RNA´s and other RNA sequences with or without the 3'TRE sequence. In our communication we will present our advances in cloning, expression, purification and activity of the yeast polymeras
Improved wear performance of ultra high molecular weight polyethylene coated with hydrogenated diamond like carbon
Hydrogenated diamond like carbon (DLCH) thin films were deposited on medical grade ultra high molecular weight polyethylene (UHMWPE) by radio frequency plasma enhanced chemical vapor deposition. The DLCH coating thicknesses ranged from 250 to 700. nm. The substrates were disks made of UHMWPEs typically used for soft components in artificial joints, namely virgin GUR 1050 and highly crosslinked (gamma irradiated in air to 100. kGy) UHMWPEs. Mechanical and tribological properties under bovine serum lubrication at body temperature were assessed on coated and uncoated polyethylenes by means of nano-hardness and ball-on-disk tests, respectively. Morphological features of the worn surfaces were obtained by confocal microscopy and scanning electron microscopy. This study confirms an increase in surface hardness and good wear resistance for coated materials after 24. h of sliding test compared to uncoated polyethylene. These results point out that to coat UHMWPE with DLCH films could be a potential method to reduce backside wear in total hip and knee arthroplasties.Ministerio de Ciencia y Educación MAT2006-12603- C02-01, CSD2008-0002
Hacia una metodología para la caracterización experimental del comportamiento a compresión de la mampostería de adobe
In the Iberian Peninsula there are numerous houses and heritage sites built with earthen materials. Nowadays, there is also a significant revival of the use of raw earth in modern architecture due to its ecological value and architectural performance. However, there is still a lack of scientific knowledge about its mechanical behavior, as well as specifications for a rigorous characterization. In this paper, an experimental analysis is carried out in order to develop a methodology for the characterization of the adobe masonry as a building material. Methodological issues for obtaining the strain field of the specimens and the choice of the Young module estimators are considered. The mechanical properties of the adobe masonry and the failure mechanisms are analyzed. In the present study, the mechanical behavior of the adobe masonry coming from the Guadalquivir riverbank in Seville (Spain) is specifically studied under compressive loads.En la Península Ibérica existen numerosas viviendas y elementos patrimoniales construidos con tierra cruda. Por otro lado, actualmente hay una tendencia creciente a revitalizar el empleo de este material en la arquitectura moderna debido a su valor ecológico y arquitectónico. Sin embargo, existe aún una falta de conocimiento científico acerca de su comportamiento mecánico, así como una falta de especificaciones para realizar una caracterización rigurosa. En este artículo se realiza un análisis experimental en aras de desarrollar una metodología para la caracterización de la mampostería de ladrillos de adobe como material estructural. Se plantean cuestiones metodológicas relativas a la obtención de las deformaciones de los especímenes y se analizan las propiedades mecánicas de la mampostería de adobe y los mecanismos de fallo. La presente investigación estudia concretamente el comportamiento mecánico de mampostería de adobe fabricada con tierra proveniente de la rivera del Guadalquivir en Sevilla (España) a compresión simple
Diagnostic performance of direct and indirect methods for assessing failure of transfer of passive immunity in dairy calves using latent class analysis
Accurate diagnosis of failure of transfer of passive immunity (FTPI) in newborn calves is an essential component of dairy farm management plan. Several methods (direct and indirect) are available for diagnosis of FTPI in dairy calves. However, the indirect methods offer an advantage over the direct methods in not requiring an experienced veterinarian, rapid, cost efficient and can be performed under field-setting. The objective of this study was to estimate the diagnostic performance of radial immunodiffusion (RID) assay, transmission infrared (TIR) spectroscopy and digital Brix refractometer for diagnosis of FTPI in dairy calves using latent class models at four cut-off values of digital Brix refractometer. Holstein calves (n = 691) from 40 commercial dairy farms in the four Atlantic Canada provinces were blood-sampled and tested for detection of FTPI. Results showed that the number of calves with FTPI was 253 (36.6%) by RID, 194 (28.1%) by TIR and 204 (29.5%) by Brix refractometer at cut-off value of 8.2%. Estimates of SeRID was higher than SeTIR and SeBrix, at all Brix refractometer cut-offs, but with increase of Brix refractometer cut-off from 8.2 to 8.5%, SeRID and SeTIR were decreased from 96.0% (95% PCI: 88.0–99.0) and 79.0% (95% PCI: 70.0–85.0), to 92.0% (95% PCI: 77.0–99.0) and 74.0% (95% PCI: 61.0–82.0), respectively. SpRID and SpTIR were always higher than SpBrix at all tested cut-offs and were above 92.0%, and 96.0%, respectively. With increasing the cut-off of Brix refractometer from 8.2 to 8.5%, SeBrix estimate has remarkably increased from 79.0% (95% PCI: 70.0–96.0) to 95.0% (95% PCI: 87.0–100.0), respectively. Whilst, SpBrix was decreased from 95.0% (95% PCI: 91.0–98.0) at cut-off 8.2% to 84.0% (95% PCI: 78.0–94.0) at cut-off 8.5%. In conclusion, RID has a higher Se than TIR and Brix, if the latter is used with cut-offs of 8.2% or 8.3%. However, the higher the cut-off, the more comparable sensitivities of RID and digital Brix refractometer. The median estimate of SpTIR was always higher than SpRID and SpBrix at all tested cut-offs. However, the 95% confidence interval estimates of the three tests were overlapping across the tested cut-offs of digital Brix refractometer reflecting the inability to prefer a test over the other based on the Sp estimate.info:eu-repo/semantics/acceptedVersio
De la recreación a la violencia
En este proyecto se investigará el consumo de sustancias ilícitas (drogas) en jóvenes estudiantes de 18 a 25 años de nivel socioeconómico de clase media alta (NSE C+) —en este segmento se considera a las personas con ingresos o nivel de
vida ligeramente superior al medio del Área Metropolitana de Guadalajara (AMG)— de universidades como la de Guadalajara (UdG), ITESO y la Marista. Se indagará en torno a las razones del consumo de este tipo de sustancias que pueden perjudicar la salud física y mental, y su relación con la violencia que se vive en el estado de Jalisco. ¿Hay una relación directa entre el consumo de drogas y la tendencia a la violencia en los jóvenes
Identificação de deficiências minerais de bovinos na microrregião Alto Purus-Acre.
A Unidade de Execução de Pesquisa de Âmbito Estadual - UEPAE/Rio Branco, vem desenvolvendo estudos com os objetivos de identificar as deficiências minerais de bovinos na microrregião Alto Purus-Acre, determinando as interrelações entre os níveis de minerais no solo, nas forrageiras e nos tecidos animais durante as estações chuvosa e seca.bitstream/item/145816/1/1097.pd
Estudio de la tipología de preguntas sobre las temáticas átomo, tabla periódica y enlace químico en las pruebas de acceso a la universidad en Andalucía
Este trabajo analiza las pruebas de acceso a la universidad de química en Andalucía desde las temáticas átomo/tabla periódica (ATP) y enlace químico (EQ), estudiando su frecuencia de aparición y la tipología de preguntas con el sistema de categorías de Smith et al. (definición, algorítmicas y conceptuales). Los resultados muestran que son temáticas poco abordadas (5.4% ATP y 9.4% EQ), a pesar de su importancia en la química escolar. En ningún caso aparecen preguntas de tipo algorítmico y la mayoría son conceptuales en ambas temáticas. Son mayoritarias cuestiones de análisis e interpretación de datos (87%) en el tema ATP, y de explicación de ideas subyacentes y predicción de resultados (85%) y análisis de representación pictórica (76%) en EQ. Sólo el 45% y 13% son cuestiones de definición ATP y EQ, respectivamente
Intercellular Diffusion of a Fluorescent Sucrose Analog via the Septal Junctions in a Filamentous Cyanobacterium
D.J.N. was supported by a Queen Mary University of London College studentship. M.N.M. was the recipient of an FPU (Formación del Personal Universitario) fellowship from the Spanish Government. Work in Seville was supported by grant BFU2011-22762 from Plan Nacional de Investigación, Spain, cofinanced by the European Regional Development Fund, and by Plan Andaluz de Investigación, Regional Government of Andalucía (grant P10-CVI-6665). Research in Tübingen was supported by the Deutsche Forschungsgemeinschaft (SFB766)
Vortex solitons of the discrete Ginzburg-Landau Equation
We have found several families of vortex soliton solutions in two-dimensional
discrete dissipative systems governed by the cubic-quintic complex
Ginzburg-Landau equation. There are symmetric and asymmetric solutions, and
some of them have simultaneously two different topological charges. Their
regions of existence and stability are determined. Additionally, we have
analyzed the relation- ship between dissipation and stability for a number of
solutions. We have obtained that dissipation favours the stability of the
solutions.Comment: 7 pages, 11 figure
- …