2,143 research outputs found
Responsiveness of bovine cumulus-oocyte-complexes (COC) to porcine and recombinant human FSH, and the effect of COC quality on gonadotropin receptor and Cx43 marker gene mRNAs during maturation in vitro
Substantially less development to the blastocyst stage occurs in vitro than in vivo and this may be due to deficiencies in oocyte competence. Although a large proportion of bovine oocytes undergo spontaneous nuclear maturation, less is known about requirements for proper cytoplasmic maturation. Commonly, supraphysiological concentrations of FSH and LH are added to maturation media to improve cumulus expansion, fertilization and embryonic development. Therefore, various concentrations of porcine FSH (pFSH) and recombinant human FSH (rhFSH) were investigated for their effect on bovine cumulus expansion in vitro. Expression of FSHr, LHr and Cx43 mRNAs was determined in cumulus-oocyte complexes to determine whether they would be useful markers of oocyte competence. In serum-free media, only 1000 ng/ml pFSH induced marked cumulus expansion, but the effect of 100 ng/ml pFSH was amplified in the presence of 10% serum. In contrast, cumulus expansion occurred with 1 ng/ml rhFSH in the absence of serum. FSHr mRNA was highest at 0–6 h of maturation, then abundance decreased. Similarly, Cx43 mRNA expression was highest from 0–6 h but decreased by 24 h of maturation. However, the relative abundance of LHr mRNA did not change from 6–24 h of maturation. Decreased levels of FSHr, LHr and Cx43 mRNAs were detected in COCs of poorer quality. In conclusion, expansion of bovine cumulus occurred at low doses of rhFSH in serum-free media. In summary, FSHr, LHr and Cx43 mRNA abundance reflects COC quality and FSHr and Cx43 mRNA expression changes during in vitro maturation; these genes may be useful markers of oocyte developmental competence
A Consideration of Biomarkers to be Used for Evaluation of Inflammation in Human Nutritional Studies
To monitor inflammation in a meaningful way, the markers used must be valid: they must reflect the inflammatory process under study and they must be predictive of future health status. In 2009, the Nutrition and Immunity Task Force of the International Life Sciences Institute, European Branch, organized an expert group to attempt to identify robust and predictive markers, or patterns or clusters of markers, which can be used to assess inflammation in human nutrition studies in the general population. Inflammation is a normal process and there are a number of cells and mediators involved. These markers are involved in, or are produced as a result of, the inflammatory process irrespective of its trigger and its location and are common to all inflammatory situations. Currently, there is no consensus as to which markers of inflammation best represent low-grade inflammation or differentiate between acute and chronic inflammation or between the various phases of inflammatory responses. There are a number of modifying factors that affect the concentration of an inflammatory marker at a given time, including age, diet and body fatness, among others. Measuring the concentration of inflammatory markers in the bloodstream under basal conditions is probably less informative compared with data related to the concentration change in response to a challenge. A number of inflammatory challenges have been described. However, many of these challenges are poorly standardised. Patterns and clusters may be important as robust biomarkers of inflammation. Therefore, it is likely that a combination of multiple inflammatory markers and integrated readouts based upon kinetic analysis following defined challenges will be the most informative biomarker of inflammation. Copyright © ILSI Europe 2013.Peer Reviewe
Propiedades f?sicas y mec?nicas de la madera de la especie Sangre gallina Vismia baccifera (L) Triana y planch procedente del Bajo Calima, municipio de Buenaventura.
72 p. Recurso Electr?nicoLa explotaci?n maderera es una de las principales actividades econ?micas de las
comunidades del pacifico colombiano, ?sta implica procesos como la tala indiscriminada
y la comercializaci?n de madera en estado juvenil con tendencia al aprovechamiento
selectivo, desconociendo el potencial de muchas especies, lo que ocasiona un grave
deterioro del bosque. En la presente investigaci?n se estudiaron las propiedades f?sicas
y mec?nicas de la especie Vismia baccifera (L.) Triana y Planch, proveniente de la regi?n
del Bajo Calima, Buenaventura, con el fin de ampliar el conocimiento acerca de las
especies maderables de la zona, lo cual permite plantear soluciones a problem?ticas
relacionadas con el manejo forestal. Las propiedades f?sicas determinadas fueron las
contracciones (longitudinales, transversales y volum?tricas), la densidad b?sica y en sus
diferentes estados (verde, seca al aire y anhidra). Las propiedades mec?nicas evaluadas
fueron: compresi?n paralela y perpendicular al grano, flexi?n est?tica, cizallamiento
paralelo al grano, dureza, arrancamiento de clavos y tenacidad. La metodolog?a
empleada corresponde a una adaptaci?n de las Normas T?cnicas Colombianas
ICONTEC para la realizaci?n de ensayos en madera. Con los resultados obtenidos se
clasific? la madera de la especie de acuerdo a las normas DIN y ASTM. Se encontr? que
la densidad b?sica de la especie es 0,47 g/cm3, es decir que la madera de este ?rbol es
blanda. Las propiedades mec?nicas en general se clasificaron como medias y bajas, por
lo tanto se recomienda emplear esta especie en construcciones de estructuras livianas.
Palabras clave: Propiedades f?sicas, Propiedades mec?nicas, Bajo Calima, Vismia
bacciferaLogging is one of the main economic activities of the Colombian Pacific communities. It
involves processes such as: indiscriminate logging, and young wood commercialization
prone to selective logging. Moreover, logging does not recognize the potential of many
species, and it causes serious forest degradation. In this study, the physical and
mechanical properties of the species Vismia baccifera (L.) Triana and Planch were
assessed. The species mentioned before were from the region of Bajo Calima,
Buenaventura. The objective of this study was to increase knowledge about timber
species in the Bajo Calima area. It allows to propose solutions for forest management
problems. The identified physical properties were contractions such as: (longitudinal,
transverse and volumetric). Furthermore, wood basic density in its different phases were
(green, open air dried and anhydrous). The mechanical properties evaluated were:
parallel and perpendicular grain compression, static flexion, parallel shearing grain,
hardness, pulling nails and tenacity. The methodology corresponds to an adaptation of
the Colombian Technical Standards ICONTEC for testing wood. The results guided the
wood species classification according to DIN and ASTM standards qualified. It was found
that the basic density of this species is 0,47 g / cm3. That is to say the wood of this tree
is soft. In general, the mechanical properties were classified as medium and low.
Therefore, it is recommended to use this wood species in light structures buildings.
Keywords: Physical properties, Mechanical properties, Bajo Calima, Vismia baccifer
Trend-based analysis of a population model of the AKAP scaffold protein
We formalise a continuous-time Markov chain with multi-dimensional discrete state space model of the AKAP scaffold protein as a crosstalk mediator between two biochemical signalling pathways. The analysis by temporal properties of the AKAP model requires reasoning about whether the counts of individuals of the same type (species) are increasing or decreasing. For this purpose we propose the concept of stochastic trends based on formulating the probabilities of transitions that increase (resp. decrease) the counts of individuals of the same type, and express these probabilities as formulae such that the state space of the model is not altered. We define a number of stochastic trend formulae (e.g. weakly increasing, strictly increasing, weakly decreasing, etc.) and use them to extend the set of state formulae of Continuous Stochastic Logic. We show how stochastic trends can be implemented in a guarded-command style specification language for transition systems. We illustrate the application of stochastic trends with numerous small examples and then we analyse the AKAP model in order to characterise and show causality and pulsating behaviours in this biochemical system
Process algebra modelling styles for biomolecular processes
We investigate how biomolecular processes are modelled in process algebras, focussing on chemical reactions. We consider various modelling styles and how design decisions made in the definition of the process algebra have an impact on how a modelling style can be applied. Our goal is to highlight the often implicit choices that modellers make in choosing a formalism, and illustrate, through the use of examples, how this can affect expressability as well as the type and complexity of the analysis that can be performed
Spin and orbital dynamics through the metal-to-insulator transition in CdOsO probed with high-resolution RIXS
High-resolution resonant inelastic x-ray scattering (RIXS) measurements
(E = 46 meV) have been performed on CdOsO through the
metal-to-insulator transition (MIT). A magnetic excitation at 125 meV evolves
continuously through the MIT, in agreement with recent Raman scattering
results, and provides further confirmation for an all-in, all-out magnetic
ground state. Asymmetry of this feature is likely a result of coupling between
the electronic and magnetic degrees of freedom. We also observe a broad
continuum of interband excitations centered at 0.3 eV energy loss. This is
indicative of significant hybridization between Os 5 and O 2 states, and
concurrent itinerant nature of the system. In turn, this suggests a possible
break down of the free-ion model for CdOsO.Comment: Accepted in Physical Review B (10 pages
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