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Search Results: 1 - 10 of 401178 matches for " M. Ema Molas "
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Prevalence and Factors Associated with Vitamin D Deficiency and Hyperparathyroidism in HIV-Infected Patients Treated in Barcelona
Elisabet Lerma,M. Ema Molas,M. Milagro Montero,Ana Guelar
ISRN AIDS , 2012, DOI: 10.5402/2012/485307
Prevalence and Factors Associated with Vitamin D Deficiency and Hyperparathyroidism in HIV-Infected Patients Treated in Barcelona
Elisabet Lerma,M. Ema Molas,M. Milagro Montero,Ana Guelar,Alicia González,Judith Villar,Adolf Diez,Hernando Knobel
ISRN AIDS , 2012, DOI: 10.5402/2012/485307
Abstract: Vitamin D deficiency is an important problem in patients with chronic conditions including those with human immunodeficiency virus (HIV) infection. The aim of this cross-sectional study was to identify the prevalence and factors associated with vitamin D deficiency and hyperparathyroidism in HIV patients attended in Barcelona. Cholecalciferol (25OH vitamin D3) and PTH levels were measured. Vitamin D insufficiency was defined as 25(OH) D < 20?ng/mL and deficiency as <12?ng/mL. Hyperparathyroidism was defined as PTH levels >65?pg/mL. Cases with chronic kidney failure, liver disease, treatments or conditions potentially affecting bone metabolism were excluded. Among the 566 patients included, 56.4% were exposed to tenofovir. Vitamin D insufficiency was found in 71.2% and 39.6% of those had deficiency. PTH was measured in 228 subjects, and 86 of them (37.7%) showed high levels. Adjusted predictors of vitamin D deficiency were nonwhite race and psychiatric comorbidity, while lipoatrophy was a protective factor. Independent risk factors of hyperparathyroidism were vitamin D < 12?ng/mL (OR: 2.14, CI 95%: 1.19–3.82, P: 0.01) and tenofovir exposure (OR: 3.55, CI 95%: 1.62–7.7, P: 0.002). High prevalence of vitamin deficiency and hyperparathyroidism was found in an area with high annual solar exposure. 1. Introduction Vitamin D is a steroid liposoluble hormone and can be made available to the individuals in two forms. First, vitamin D3 or cholecalciferol is synthesized in the skin in response to ultraviolet B radiation and is present in oil-rich fish (salmon, mackerel, and herring), egg yolks, and liver [1]. Second, vitamin D2 or ergocalciferol is obtained from the UV irradiation of the yeast sterol ergosterol and is found in sun-exposed mushrooms [2]. Both vitamins undergo identical metabolism, and as they are biologically inert, they require two hydroxylations, in the liver and in the kidney, to become 1,25dihydroxyvitamin D [1,25(OH)2D] which is the biologically active form of the hormone [3, 4]. In the intestine this stimulates the absorption of calcium and phosphorus, and it helps to regulate the metabolism of both minerals within bone and kidney interaction [5]. Assessment of vitamin D is based on measurement of serum 25(OH)D [6, 7] that is the most stable and plentiful metabolite of vitamin D in serum and has a half-life about 21 days [8]. The main source of vitamin D is exposure to sunlight [9, 10]. Therefore, an insufficient exposure to sunlight is a major cause of vitamin D deficiency. Other causes of vitamin deficiency are sunscreen sun protection [2],
The effect of column purification on cDNA indirect labelling for microarrays
M Lia Molas, John Z Kiss
Plant Methods , 2007, DOI: 10.1186/1746-4811-3-9
Abstract: We used a standard procedure to label cDNA for microarray hybridization and employed different types of column chromatography for cDNA purification. After purifying labelled cDNA, we used the Agilent 2100 Bioanalyzer and agarose gel electrophoresis to assess the quality of the labelled cDNA before its hybridization onto a microarray platform. There were major differences in the cDNA profile (i.e. cDNA fragment lengths and abundance) as a result of using four different columns for purification. In addition, different columns have different efficiencies to remove rRNA contamination. This study indicates that the appropriate column to use in this type of protocol has to be experimentally determined. Finally, we present new evidence establishing the importance of testing the method of purification used during an indirect labelling procedure. Our results confirm the importance of assessing the quality of the sample in the labelling procedure prior to hybridization onto a microarray platform.Standardization of column purification systems to be used in labelling procedures will improve the reproducibility of microarray results among different laboratories. In addition, implementation of a quality control check point of the labelled samples prior to microarray hybridization will prevent hybridizing a poor quality sample to expensive micorarrays.Microarray technology has become widely used to evaluate global gene expression. Despite the increasing reliance on this technology, the poor reproducibility of microarray data among laboratories and across platforms is still a major concern [1]. Currently, there are a variety of platforms available, ranging from cDNA to oligonucleotide microarrays, to customized arrays, and to commercially developed microarrays. In addition, there is a large diversity in the procedures used by different laboratories for RNA manipulation and labelling as well as software used to analyze the output data. As a result of these multifaceted approaches to
Rese a de "Manual de Plantas de Costa Rica" de Hammel, B. E.; M. H. Grayum, C. Herrera & N. Zamora (eds.)
María Ema Múlgura
Darwiniana , 2008,
Ultrastructural response of cabbage outer leaf mesophyll cells (Brassica oleracea L.) to excess of nickel
Jolanta Molas
Acta Societatis Botanicorum Poloniae , 1997, DOI: 10.5586/asbp.1997.036
Abstract: Changes in the structure and in the ultrastructure of cabbage outer leaf mesophyll cells [Brassica oleracea L.] cv. S awa from Enkhouizen were examined by means of light and electron microscopy. The examined plants were grown on the basic Murashige and Skoog medium with addition of excesive concentrations of nickel (added as NiSO4 x 7H2O),i.e. Ni 5, Ni 10 and Ni 20 mg/dm3. In Ni 5 mg samples mainly adaptation changes to the conditions of stress were observed. These changes were manifested by the increase of cytoplasm content and by cytoplasm vacuolization, by the increase of nucleus and nucleous volume, nucleolus vacuolization, the increase of plasmalemma invaginations and of the amount of rough ER, by the central arrangement of smooth ER and of the thylakoids of chloroplasts; it was also shown by the growth of the number of mitochondria and of peroxisomes in the cell. In Ni 10 mg samples, apart from adaptation changes, such as the increase of the nucleus volume, increase of plasmalemma invaginations, cytoplasm and nucleolus vacuolization, degeneration changes were also observed. They concerned mainly the nucleus (the increasing amount of condensed chromatin), ER (swelling and fragmentation of rER and sER), mitochondrium (swelling and reduction of cristae), Golgi apparatus (disintegration and decay) and chloroplasts (changes of shape, swelling and reduction of thylakoids, disappearance of starch and presence of big plastoglobuli). In Ni 20 mg samples cell protoplasts were in different stages of degeneration and the cell organelles that were identifiable, were usually damaged.
Background charges and quantum effects in quantum dots transport spectroscopy
M. Pierre,M. Hofheinz,X. Jehl,M. Sanquer,G. Molas,M. Vinet,S. Deleonibus
Physics , 2008, DOI: 10.1140/epjb/e2009-00258-4
Abstract: We extend a simple model of a charge trap coupled to a single-electron box to energy ranges and parameters such that it gives new insights and predictions readily observable in many experimental systems. We show that a single background charge is enough to give lines of differential conductance in the stability diagram of the quantum dot, even within undistorted Coulomb diamonds. It also suppresses the current near degeneracy of the impurity charge, and yields negative differential lines far from this degeneracy. We compare this picture to two other accepted explanations for lines in diamonds, based respectively on the excitation spectrum of a quantum dot and on fluctuations of the density-of-states in the contacts. In order to discriminate between these models we emphasize the specific features related to environmental charge traps. Finally we show that our model accounts very well for all the anomalous features observed in silicon nanowire quantum dots.
Individual charge traps in silicon nanowires: Measurements of location, spin and occupation number by Coulomb blockade spectroscopy
M. Hofheinz,X. Jehl,M. Sanquer,G. Molas,M. Vinet,S. Deleonibus
Physics , 2005, DOI: 10.1140/epjb/e2006-00452-x
Abstract: We study anomalies in the Coulomb blockade spectrum of a quantum dot formed in a silicon nanowire. These anomalies are attributed to electrostatic interaction with charge traps in the device. A simple model reproduces these anomalies accurately and we show how the capacitance matrices of the traps can be obtained from the shape of the anomalies. From these capacitance matrices we deduce that the traps are located near or inside the wire. Based on the occurrence of the anomalies in wires with different doping levels we infer that most of the traps are arsenic dopant states. In some cases the anomalies are accompanied by a random telegraph signal which allows time resolved monitoring of the occupation of the trap. The spin of the trap states is determined via the Zeeman shift.
A simple and controlled single electron transistor based on doping modulation in silicon nanowires
M. Hofheinz,X. Jehl,M. Sanquer,G. Molas,M. Vinet,S. Deleonibus
Physics , 2006, DOI: 10.1063/1.2358812
Abstract: A simple and highly reproducible single electron transistor (SET) has been fabricated using gated silicon nanowires. The structure is a metal-oxide-semiconductor field-effect transistor made on silicon-on-insulator thin films. The channel of the transistor is the Coulomb island at low temperature. Two silicon nitride spacers deposited on each side of the gate create a modulation of doping along the nanowire that creates tunnel barriers. Such barriers are fixed and controlled, like in metallic SETs. The period of the Coulomb oscillations is set by the gate capacitance of the transistor and therefore controlled by lithography. The source and drain capacitances have also been characterized. This design could be used to build more complex SET devices.
Lectotipificación e identificación de Chenopodium stuckertii (Chenopodiaceae)
Múlgura de Romero,María Ema; Ariza Espinar,Luis;
Darwiniana , 2010,
Abstract: chenopodium stuckertii is identified as holmbergia tweedii and lectotypified.
Lectotipificación e identificación de Chenopodium stuckertii (Chenopodiaceae)
María Ema Múlgura de Romero,Luis Ariza Espinar
Darwiniana , 2010,
Abstract: Chenopodium stuckertii se identifica como Holmbergia tweedii y se lectotipifica.
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