992 resultados para Certified reference materials


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In this paper, a phenomenologically motivated magneto-mechanically coupled finite strain elastic framework for simulating the curing process of polymers in the presence of a magnetic load is proposed. This approach is in line with previous works by Hossain and co-workers on finite strain curing modelling framework for the purely mechanical polymer curing (Hossain et al., 2009b). The proposed thermodynamically consistent approach is independent of any particular free energy function that may be used for the fully-cured magneto-sensitive polymer modelling, i.e. any phenomenological or micromechanical-inspired free energy can be inserted into the main modelling framework. For the fabrication of magneto-sensitive polymers, micron-size ferromagnetic particles are mixed with the liquid matrix material in the uncured stage. The particles align in a preferred direction with the application of a magnetic field during the curing process. The polymer curing process is a complex (visco) elastic process that transforms a fluid to a solid with time. Such transformation process is modelled by an appropriate constitutive relation which takes into account the temporal evolution of the material parameters appearing in a particular energy function. For demonstration in this work, a frequently used energy function is chosen, i.e. the classical Mooney-Rivlin free energy enhanced by coupling terms. Several representative numerical examples are demonstrated that prove the capability of our approach to correctly capture common features in polymers undergoing curing processes in the presence of a magneto-mechanical coupled load.

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The wide variety of Leishmania species responsible for human American cutaneous leishmaniasis combined with the immune mechanisms of the host results in a large spectrum of clinical, histopathological, and immunopathological manifestations. At the middle of this spectrum are the most frequent cases of localized cutaneous leishmaniasis (LCL) caused by members of the subgenera Leishmania and Viannia, which respond well to conventional therapy. The two pathogenicity extremes of the spectrum generally recognized are represented at the hypersensitivity pole by mucocutaneous leishmaniasis (MCL) and at the hyposensitivity pole by anergic diffuse cutaneous leishmaniasis (ADCL). Following the present study on the clinical, histopathological and immunopathological features of cutaneous leishmaniasis in Amazonian Brazil, we propose the use of the term "borderline disseminated cutaneous leishmaniasis" for the disseminated form of the disease, due to parasites of the subgenera Leishmania and Viannia, which might be regarded as intermediate between LCL and the extreme pathogenicity poles MCL and ADCL.

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This study compares smear, growth in Lowenstein-Jensen medium, and in-house polymerase chain reaction (PCR) techniques for the detection of Mycobacterium tuberculosis. A total of 72 specimens from 72 patients with clinical symptoms of tuberculosis, including 70 sputum and two bronchial aspirate samples, were tested in parallel by smear, culture, and in-house PCR techniques. From these, 48 (66.6%) were negative by the 3 methods, 2 (2.8%) were smear positive and negative by culture and in-house PCR, 11 (15.3%) were both smear and culture negative, and in-house PCR positive, 7 (9.7%) were positive by the 3 methods, 2 (2.8%) were positive by smear and culture, and negative by PCR, 2 (2.8%) were positive by culture and PCR, but smear negative. After the resolution of discrepancies in PCR results, the sensitivity and specificity for in-house PCR technique to M. tuberculosis relative to the culture, were 81.8% and 81.9%, respectively. These results confirm that this method, in-house PCR, may be a sensitive and specific technique for M. tuberculosis detection, occurring in both positive and negative smear and negative cultures.

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Freshwater snails belonging to the genus Biomphalaria act as intermediate hosts for the parasite trematode Schistosoma mansoni in Africa and in the neotropical region. Identification of such molluscs is carried out based on morphological characters and the presence of cercariae is verified through squeezing snails between two glass slides or by exposing them to artificial light. However, sometimes, the material collected includes molluscs with decomposed bodies or, yet, only empty shells, which precludes their identification and S. mansoni detection. Due to these difficulties, we have developed a methodology in which DNA may be extracted from traces of organic material from inside shells in order to identify molluscs through polymerase chain reaction and restriction fragment length polymorphism and to detect S. mansoni into these snails, by using low stringency polymerase chain reaction. Species-specific profiles obtained from B. glabrata, B. straminea, and B. tenagophila snails and their shells, maintained in laboratory for ten years, showed the same profiles. S. mansoni profiles showed to be present in shell specimens as far as the eighth week after being removed from aquarium.

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La douleur neuropathique est définie comme une douleur causée par une lésion du système nerveux somato-sensoriel. Elle se caractérise par des douleurs exagérées, spontanées, ou déclenchées par des stimuli normalement non douloureux (allodynie) ou douloureux (hyperalgésie). Bien qu'elle concerne 7% de la population, ses mécanismes biologiques ne sont pas encore élucidés. L'étude des variations d'expressions géniques dans les tissus-clés des voies sensorielles (notamment le ganglion spinal et la corne dorsale de la moelle épinière) à différents moments après une lésion nerveuse périphérique permettrait de mettre en évidence de nouvelles cibles thérapeutiques. Elles se détectent de manière sensible par reverse transcription quantitative real-time polymerase chain reaction (RT- qPCR). Pour garantir des résultats fiables, des guidelines ont récemment recommandé la validation des gènes de référence utilisés pour la normalisation des données ("Minimum information for publication of quantitative real-time PCR experiments", Bustin et al 2009). Après recherche dans la littérature des gènes de référence fréquemment utilisés dans notre modèle de douleur neuropathique périphérique SNI (spared nerve injury) et dans le tissu nerveux en général, nous avons établi une liste de potentiels bons candidats: Actin beta (Actb), Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal proteins 18S (18S), L13a (RPL13a) et L29 (RPL29), hypoxanthine phosphoribosyltransferase 1 (HPRT1) et hydroxymethyl-bilane synthase (HMBS). Nous avons évalué la stabilité d'expression de ces gènes dans le ganglion spinal et dans la corne dorsale à différents moments après la lésion nerveuse (SNI) en calculant des coefficients de variation et utilisant l'algorithme geNorm qui compare les niveaux d'expression entre les différents candidats et détermine la paire de gènes restante la plus stable. Il a aussi été possible de classer les gènes selon leur stabilité et d'identifier le nombre de gènes nécessaires pour une normalisation la plus précise. Les gènes les plus cités comme référence dans le modèle SNI ont été GAPDH, HMBS, Actb, HPRT1 et 18S. Seuls HPRT1 and 18S ont été précédemment validés dans des arrays de RT-qPCR. Dans notre étude, tous les gènes testés dans le ganglion spinal et dans la corne dorsale satisfont au critère de stabilité exprimé par une M-value inférieure à 1. Par contre avec un coefficient de variation (CV) supérieur à 50% dans le ganglion spinal, 18S ne peut être retenu. La paire de gènes la plus stable dans le ganglion spinal est HPRT1 et Actb et dans la corne dorsale il s'agit de RPL29 et RPL13a. L'utilisation de 2 gènes de référence stables suffit pour une normalisation fiable. Nous avons donc classé et validé Actb, RPL29, RPL13a, HMBS, GAPDH, HPRT1 et 18S comme gènes de référence utilisables dans la corne dorsale pour le modèle SNI chez le rat. Dans le ganglion spinal 18S n'a pas rempli nos critères. Nous avons aussi déterminé que la combinaison de deux gènes de référence stables suffit pour une normalisation précise. Les variations d'expression génique de potentiels gènes d'intérêts dans des conditions expérimentales identiques (SNI, tissu et timepoints post SNI) vont pouvoir se mesurer sur la base d'une normalisation fiable. Non seulement il sera possible d'identifier des régulations potentiellement importantes dans la genèse de la douleur neuropathique mais aussi d'observer les différents phénotypes évoluant au cours du temps après lésion nerveuse.

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Species-specific chemical signals released through urine, sweat, saliva and feces are involved in communication between animals. Urinary biochemical constituents along with pheromones may contribute to variation across reproductive cycles and facilitate to estrus detection. Hence, the present study was designed to analyze such biochemical profiles, such as proteins, carbohydrates, lipids, fatty acids, in response with steroid hormones such as estradiol and progesterone. The experimental groups were normal, prepubertal, ovariectomized, and ovariectomized with estrogentreated female mice. In normal mice, the protein and lipid concentrations in urine were significantly higher in proestrus and estrus phases and the quantity of fatty acids was also comparatively higher in estrus. Furthermore, certain fatty acids, namely tridecanoic, palmitic and oleic acids, were present during proestrus and estrus phases, but were exclusively absent in ovariectomized mice. However, the carbohydrate level was equally maintained throughout the four phases of estrous cycle. For successful communication, higher concentrations of protein and specific fatty acids in estrus are directly involved. The significant increase in estradiol at estrus and progesterone at metestrus seems to be of greater importance in the expression pattern of biochemical constituents and may play a notable role in estrous cycle regulation. Thus, we conclude that the variations observed in the concentration of the biochemical constituents depend on the phase of the reproductive cycle as well as hormonal status of animals. The appearance of protein and specific fatty acids during estrus phase raises the possibility to use these as a urinary indicators for estrus detection.

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This report reviews various measures of deprivation in order to be able to monitor socio-economic inequalities in cancer incidence, survival and service provision in the future.

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An historical review is given of American visceral leishmaniasis (AVL), with particular reference to the eco-epidemiology of the disease in Brazil. Following the first records of AVL in this country, in 1934, the sandfly Lutzomyia longipalpis (Lutz and Neiva, 1912) was incriminated as the principal vector. It is now generally accepted, however, that there exist a number of cryptic species under the name of Lu. longipalpis s.l. and that variations in the quantity of the vasodilatory peptide maxadilan in the saliva of flies from different populations of Lu. longipalpis s.l., may account for the variable clinical manifestations of AVL seen in different geographic regions. Distribution of AVL has been shown to extend throughout most of South and Central America, with the domestic dog serving as the principal reservoir of infection for man. However, while one hypothesis suggests that the causative parasite is Leishmania infantum, imported from Europe with the Portuguese and Spanish colonists, the demonstration of a high rate of benign, inapparent infection in foxes in Amazonian Brazil raised an opposing suggestion that the parasite is indigenous to the Americas. Recent reports of similar infections in native marsupials, and possibly rodents, tend to support this view, particularly as Lu. longipalpis is primordially a silvatic sandfly. Although effective control measures in foci of the disease will diminish the number of canine and human infections, the presence of such an enzootic in a variety of native animals will render the total eradication of AVL unlikely.

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This is the Terms of Reference for the review of Allied Health Professional (AHP) support for children/young people with statements of special educational needs.It outlines expectations of the review and should be read in conjunction with the Project Initiation Document (PID) for Phase 1of the review, the Terms of Reference for the Project Board and the Engagement Plan for phase 1.

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This is the Terms of Reference for the Project Board of the review of Allied Health Professions (AHP) support for children/young people with statements of special educational needs.It outlines the:Purpose of the Project BoardResponsibilities of the Project BoardMembership of the Project Board

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To assess the prevalence of primary resistance of human immunodeficiency virus type 1 (HIV-1) to antiretrovirals, 84 patients chronically infected with HIV without prior antiretroviral treatment from Northeast Brazil were studied. Genotyping was performed using the ViroSeqTM Genotyping System. Thimidine analog mutations occurred in 3 (3.6%) patients. Accessory mutations related to NRTI occurred in 6 (7.1%) and related to PI in 67 (79.8%). Subtypes B (72.6%), F (22.6%), B/F 3 (3.6%), and C (1.2%) were detected. A low prevalence of major mutations related to NRTI in patients chronically infected by HIV was observed.

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We describe an innovative use of multimedia materials to support training and advocacy within a schistosomiasis control programme. The Schistosomiasis Control Initiative (SCI) at Imperial College London works with selected sub-Saharan African countries to develop schistosomiasis control programmes. Two elements of the SCI programme were supported by multimedia materials developed at the Wellcome Trust in collaboration with the SCI: (1) training of programme managers, district health officers, and those delivering practical elements of the programme; and (2) advocacy targeted at decision-makers and donors. Evaluation of the materials revealed high reported ratings for both user satisfaction and impact from use of the product. From this experience we draw out several general messages about development of multimedia materials and how these will play a growing future role in promoting training within international health.

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Aquest document fa referència a un projecte d'esteganografia basat en àudio. Per tant, a continuació s'exposen les principals tècniques esteganogràfiques per manipular fitxers d'àudio.

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This factsheet provides information in the form of FAQs in relation to hepatitis B: the condition, prevalence, risks, testing, management, vaccination and treatment.