172 research outputs found
Geometrie analysis and scaling properties of calcite e-twins in the Cameros Basin (NW Iberian Chain, Spain)
One dimensional geometric analysis has been carried out in several scan lines from 885 measures of twins in calcite grains to determine grain width (in microns) and twin density (number of twins.mm-1 ) distributions. Grain width and twin density have a good fit to the log-normal frequency distribution. Twinning in calcite implies intracrystaline deformation mechanism with low shear stress. When the process begins low grain width and calcite twins are developed with a probably random distribution what could be supported by a negative exponential distribution tendency. The twinning process continues until a "critical" value of grain width and density which is going to influence in the scaling process, and becoming the distribution to log-normal type. But some data also conform to a power-law (fractal) frequency distribution from determined range or sizes (300 to WOO mm) and density (2 to W twins.mm-1) with some superimposed random (negative-exponential) elements, possible due to the irregularities at grain scale, but also because this systems show multifractal behavior
La agricultura familiar relacionado con los objetivos de desarrollo sostenible uno y dos en los distritos de Rupa Rupa y Castillo Grande, región Huánuco
El objetivo de la investigacion fue evaluar la relación del aporte de la agricultura familiar para el cumplimiento de los objetivos de desarrollo sostenible uno y dos al 2030, asimismo caracterizar y tipificar la agricultura familiar en los distritos de Rupa Rupa y Castillo Grande, región Huánuco. Se trabajó con una muestra de 60 fundos familiares con un nivel de investigación descriptivo y tipo cualitativo-explicativo. Se utilizó el modelo estadístico que corresponde a un diseño completamente al azar, asimismo la prueba de media DGC para determinar diferencias significativas entre los tipos de sistemas. Los resultados mostraron que la agricultura familiar aporta al cumplimiento de los objetivos de desarrollo sostenible uno y dos al 2030 en los distritos de Rupa Rupa y Castillo Grande, debido a que son sistemas integrales de producción, tipificado como un agroecosistema biodiverso, constituida por componentes agrícola, forestal y pecuario, y el funcionamiento de este sistema, está instalado en un área de terreno cuya superficie trabajada en promedio va de 1 a 5 ha y son de manejo familiar, dando soporte a la disminución de la pobreza, y el hambre con una mejor nutrición y promoción de una agricultura con un enfoque agroecológico. Estos sistemas se diferenciaron en tres conglomerados, el primero agrupó al 41.67%, el segundo al 38.83% y el tercero al 20% del total de fundos evaluados, sobresaliendo el conglomerado 1, seguido del 2 y finalmente el tercero, con diferencias estadísticas entre ellos
Relation of gallbladder function and Helicobacter pylori infection to gastric mucosa inflammation in patients with symptomatic cholecystolithiasis
Background. Inflammatory alterations of the gastric mucosa are commonly caused by Helicobacter pylori (Hp) infection in patients with symptomatic gallstone disease. However, the additional pathogenetic role of an impaired gallbladder function leading to an increased alkaline duodenogastric reflux is controversially discussed. Aim:To investigate the relation of gallbladder function and Hp infection to gastric mucosa inflammation in patients with symptomatic gallstones prior to cholecystectomy. Patients: Seventy-three patients with symptomatic gallstones were studied by endoscopy and Hp testing. Methods: Gastritis classification was performed according to the updated Sydney System and gallbladder function was determined by total lipid concentration of gallbladder bile collected during mainly laparoscopic cholecystectomy. Results: Fifteen patients revealed no, 39 patients mild, and 19 moderate to marked gastritis. No significant differences for bile salts, phospholipids, cholesterol, or total lipids in gallbladder bile were found between these three groups of patients. However, while only 1 out of 54 (< 2%) patients with mild or no gastritis was found histologically positive for Hp, this infection could be detected in 14 (74%) out of 19 patients with moderate to marked gastritis. Conclusion: Moderate to marked gastric mucosa inflammation in gallstone patients is mainly caused by Hp infection, whereas gallbladder function is not related to the degree of gastritis. Thus, an increased alkaline duodenogastric reflux in gallstone patients seems to be of limited pathophysiological relevance. Copyright (c) 2006 S. Karger AG, Basel
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Dengue Virus Capsid Protein Binds Core Histones and Inhibits Nucleosome Formation in Human Liver Cells
Dengue virus (DENV) is a member of the Flaviviridae and a globally (re)emerging pathogen that causes serious human disease. There is no specific antiviral or vaccine for dengue virus infection. Flavivirus capsid (C) is a structural protein responsible for gathering the viral RNA into a nucleocapsid that forms the core of a mature virus particle. Flaviviral replication is known to occur in the cytoplasm yet a large portion of capsid protein localizes to the nucleus during infection. The reasons for the nuclear presences of capsid are not completely understood. Here, we expressed mature DENV C in a tandem affinity purification assay to identify potential binding partners in human liver cells. DENV C targeted the four core histones, H2A, H2B, H3 and H4. DENV C bound recombinant histones in solution and colocalized with histones in the nucleus and cytoplasm of liver cells during DENV infection. We show that DENV C acts as a histone mimic, forming heterodimers with core histones, binding DNA and disrupting nucleosome formation. We also demonstrate that DENV infection increases the amounts of core histones in livers cells, which may be a cellular response to C binding away the histone proteins. Infection with DENV additionally alters levels of H2A phosphorylation in a time-dependent manner. The interactions of C and histones add an interesting new role for the presence of C in the nucleus during DENV infection
External validation of multidimensional prognostic indices (ADO, BODEx and DOSE) in a primary care international cohort (PROEPOC/COPD cohort)
Background: Due to the heterogeneous and systemic nature of the chronic obstructive pulmonary disease (COPD), the new guidelines are oriented toward individualized attention. Multidimensional scales could facilitate its proper clinical and prognostic assessment, but not all of them were validated in an international primary care cohort, different from the original ones used for model development. Therefore, our main aim is to assess the prognostic capacity of the ADO, BODEx and DOSE indices in primary care for predicting mortality in COPD patients and to validate the models obtained in subgroups of patients, classified by revised Global Initiative for Chronic Obstructive Lung Disease (2011) and updated Spanish Guideline (2014). Besides, we want to confirm that the prognostic capacity of all indices increases if the number of exacerbations is substituted by the interval between them and to assess the impact on health of the patient''s lifestyle, social network and adherence to treatment. Methods: Design: External validation of scales, open and prospective cohort study in primary care. Setting: 36 health centres in 6 European high, medium and low income countries. Subjects: 477 patients diagnosed with COPD, captured in clinical visit by their General Practitioner/Nurse. Predictors: Detailed patient history, exacerbations, lung function test and questionnaires at baseline. Outcomes: Exacerbations, all-cause mortality and specific mortality, within 5 years of recruitment. Analysis: Multivariate logistic regression and Cox regression will be used. Possible non-linear effect of the indices will be studied by using Structured Additive Regression models with penalised splines. Subsequently, we will assess different aspects of the regression models: discrimination, calibration and diagnostic precision. Clinical variables modulated in primary care and the interval between exacerbations will be considered and incorporated into the analysis. Discussion: The Research Agenda for General Practice/Family Medicine highlights that the evidence on predictive values of prognostic indices in primary care is scarce. A prospective cohort like that of PROEPOC/COPD provides good opportunities for research into COPD and make communication easier between family practitioners, nursing staff, pneumologists and other professionals, supporting a multi-disciplinary approach to the treatment of these patients. Trial registration:ISRCTN52402811. Date: 15/01/2015. Prospectively registered
Characterization and comparability of biosimilars: A filgrastim case of study and regulatory perspectives for Latin America
Background: Developing countries have an estimate of ten times more
approved biosimilars than developed countries. This disparity demands
the need of an objective regulation that incorporates health policies
according to the technological and economical capabilities of each
country. One of the challenges lies on the establishment of
comparability principles based on a physicochemical and biological
characterization that should determine the extent of additional
non-clinical and clinical studies. This is particularly relevant for
licensed biosimilars in developing countries, which have an extensive
clinical experience since their approval as generics, in some cases
more than a decade. To exemplify the current status of biosimilars in
Mexico, a characterization exercise was conducted on licensed
filgrastim biosimilars using pharmacopeial and extended
characterization methodologies. Results: Most of the evaluated products
complied with the pharmacopeial criteria and showed comparability in
their Critical Quality Attributes (CQAs) towards the reference product.
These results were expected in accordance with their equivalent
performance during their licensing as generics. Accordingly, a rational
approval and registration renewal scheme for biosimilars is proposed,
that considers the proper identification of CQAs and its thoroughly
evaluation using selected techniques. Conclusions: This approach
provides support to diminish uncertainty of exhibiting different
pharmacological profiles and narrows or even avoids the necessity of
comparative clinical studies. Ultimately, this proposal is intended to
improve the accessibility to high quality biosimilars in Latin America
and other developing countries
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