Biaxial Strain Transfer in Supported Graphene.

Understanding the mechanism and limits of strain transfer between supported 2D systems and their substrate is a most needed step toward the development of strain engineering at the nanoscale. This includes applications in straintronics, nanoelectromechanical devices, or new nanocomposites. Here, we have studied the limits of biaxial compressive strain transfer among SiO2, diamond, and sapphire substrates and graphene. Using high pressure-which allows maximizing the adhesion between graphene and the substrate on which it is deposited-we show that the relevant parameter governing the graphene mechanical response is not the applied pressure but rather the strain that is transmitted from the substrate. Under these experimental conditions, we also show the existence of a critical biaxial stress beyond which strain transfer become partial and introduce a parameter, α, to characterize strain transfer efficiency. The critical stress and α appear to be dependent on the nature of the substrate. Under ideal biaxial strain transfer conditions, the phonon Raman G-band dependence with strain appears to be linear with a slope of -60 ± 3 cm-1/% down to biaxial strains of -0.9%. This evolution appears to be general for both biaxial compression and tension for different experimental setups, at least in the biaxial strain range -0.9% < ε < 1.8%, thus providing a criterion to validate total biaxial strain transfer hypotheses. These results invite us to cast a new look at mechanical strain experiments on deposited graphene as well as to other 2D layered materials.

Enfermedad celíaca, esofagitis eosinofílica y alergia a cereales: ¿existe alguna conexión? Importancia de los estudios moleculares para su tipificación / Celiac disease, eosinophilic esophagitis and cereal allergies: Is there a connection? Importance of molecular studies for patients classification

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High pressure study of Li-doped fullerides, Li(x)C60 (x = 4,12), by x-ray diffraction and Raman spectroscopy.

In this article we study the alkali metal-intercalated 2D polymeric Li4C60 and the monomeric Li12C60 under pressure up to 40 GPa at room temperature, using x-ray diffraction and Raman spectroscopy. Li4C60 undergoes several transitions in the studied pressure range. At pressures lower than 8 GPa, we observed changes in both diffraction patterns and Raman scattering spectra, probably due to the displacement of Li atoms. At 8 GPa another structural and electronic transition occurs. We observe an enhancement of background and a broadening of diffraction peaks. Raman modes weaken and broaden considerably. An important structural transition occurs at around 16 GPa, in which new Raman bands exhibit features similar to those of a reported 3D C60 polymeric structure. The XRD data shows a collapse in volume with the simultaneous formation of amorphous material. The cell parameters deviate from their early pressure evolution and become less compressible. The high pressure study of highly doped monomeric Li12C60 shows that its structural integrity is retained up to 13 GPa, with increasing pressure-induced structural distortion and disorder. Above 13 GPa, Li12C60 transforms to a highly disordered state.

A first-principles study of the effect of charge doping on the 1D polymerization of C(60).

We study the interplay between charge doping and intermolecular distance in the polymerization of C(60) fullerene chains by means of density functional theory-based first-principles calculations. The potential energy surface analysis shows that both the equilibrium intermolecular distance of the unpolymerized system and the polymerization energy barrier are inversely proportional to the electron doping of the system. We analyze the origin of this charge-induced polymerization effect by studying the behavior of the system's wavefunctions around the Fermi level and the structural modifications of the molecules as a function of two variables: the distance between the centers of the molecules and the number of electrons added to the system.

Clinical significance of cross-reactivity between tobacco and latex

Background: Allergen cross-reactivity between tobacco and other species of Solanaceae family (tomato, potato, aubergine and eggplant) have been reported. We have recently studied IgE response to tobacco in asthmatic patients sensitised to Lolium perenne (Perennial rye grass pollen) and have found that 30% of the tobacco responsive patients also have latex sensitisation. Objective: The aim of our study was to investigate the possibility of cross-reactivity between tobacco and latex in asthmatic patients with IgE response to latex. Methods: A study was performed on tobacco and latex exposure in 15 patients who suffered from asthma and latex sensitisation and who were randomly chosen from our database of latex-sensitive patients. To identify tobacco and latex as possible allergens that might cause clinical specific responses, all these patients were tested with prick-tests, specific IgE to tobacco, latex and related allergens, bronchial challenge, and patch tests with tobacco, latex and nicotine. Immunological response was evaluated with immunoblotting, immunoblotting-inhibition and EAST-inhibition tests. Results: Positive prick and bronchial challenge with specific IgE>0.35kU/L to tobacco was demonstrated in 11 asthmatics who were also sensitised to rye grass. Tobacco IgE level was related with sensitisation to latex (p<0.002), but not to other vegetables belonging to the Solanaceae family. EAST-inhibition and immunoblotting-inhibition showed the existence of cross-reactivity between tobacco and latex. Conclusions: Cross-reactivity exists between latex and tobacco allergens. Smoker patients with IgE response to tobacco may be a risk population for latex sensitisation

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Clinical significance of cross-reactivity between tobacco and latex.

BACKGROUND: Allergen cross-reactivity between tobacco and other species of Solanaceae family (tomato, potato, aubergine and egg plant) have been reported. We have recently studied IgE response to tobacco in asthmatic patients sensitised to Lolium perenne (Perennial rye grass pollen) and have found that 30% of the tobacco responsive patients also have latex sensitisation. OBJECTIVE: The aim of our study was to investigate the possibility of cross-reactivity between tobacco and latex in asthmatic patients with IgE response to latex. METHODS: A study was performed on tobacco and latex exposure in 15 patients who suffered from asthma and latex sensitisation and who were randomly chosen from our database of latex-sensitive patients. To identify tobacco and latex as possible allergens that might cause clinical specific responses, all these patients were tested with prick-tests, specific IgE to tobacco, latex and related allergens, bronchial challenge, and patch tests with tobacco, latex and nicotine. Immunological response was evaluated with immunoblotting, immunoblotting-inhibition and EAST-inhibition tests. RESULTS: Positive prick and bronchial challenge with specific IgE>0.35 kU/L to tobacco was demonstrated in 11 asthmatics who were also sensitised to rye grass. Tobacco IgE level was related with sensitisation to latex (p<0.002), but not to other vegetables belonging to the Solanaceae family. EAST-inhibition and immunoblotting-inhibition showed the existence of cross-reactivity between tobacco and latex. CONCLUSIONS: Cross-reactivity exists between latex and tobacco allergens. Smoker patients with IgE response to tobacco may be a risk population for latex sensitisation.

Dimetilarginina asimétrica (ADMA) en diferentes enfermedades / Asymmetric dimethylarginine (ADMA) in different pathologies

La dimetilarginina asimétrica (ADMA) se forma como subproducto metabólico del almacenamiento continuo de proteínas en las células del cuerpo. Hace más de una década se propuso que ADMA ejerce efectos biológicos sin inhibir la síntesis de NO. El papel fisiopatológico de ADMA ha sido elucidado según los esfuerzos de colaboración de diferentes grupos de investigación en el mundo. Hoy por hoy, se admite que ADMA puede desempeñar un papel prominente en la patogenia y en la progresión de enfermedades cardiovasculares, específicamente en la aterosclerosis. La ADMA es un inhibidor competitivo endógeno de la eNOS, descubierto en pacientes con insuficiencia renal. La denominación se debe a que los 2 metilos están unidos a un solo nitrógeno del grupo guanido. ADMA está aumentada en la insuficiencia renal y en otras situaciones patológicas como la hipercolesterolemia, la aterosclerosis y la hipertensión arterial. El aumento en las concentraciones de ADMA supone un importante efecto inhibidor en la enzima. Algunos estudios de intervención indican que la suplementación con arginina mejora la función endotelial en pacientes con enfermedad coronaria(AU)

Asymmetric dimethylarginine (ADMA) is formed as a metabolic byproduct of continuous protein turnover in the cytoplasm of all human cells. For more than a decade it was proposed that ADMA exerted its biological effects by inhibiting the synthesis of NO. The pathophysiological role of ADMA has been clarified in more detail by collaborative efforts of different research groups around the world. Today, it is recognized that the ADMA can play a prominent role in the pathogenesis and progression of cardiovascular diseases, specifically atherosclerosis. Asymmetrical dimethyl-arginine (ADMA) is a competitive inhibitor of endogenous eNOS, discovered in patients with renal insufficiency. Its name comes from the methyl groups bound to the guanidine nitrogen. ADMA is increased in kidney failure and other pathological situations such as hypercholesterolemia, atherosclerosis and hypertension. The increase in the concentrations of ADMA shows a significant inhibitory effect on the eNOS enzyme. Inhibition can be reduced by increasing the concentration of substrate available. Indeed, some intervention studies indicate that arginine supplements improve endothelial function in patients with coronary heart disease(AU)

New phase transition of solid bromine under high pressure.

Solid bromine has been studied by x-ray absorption spectroscopy experiments up to a maximum pressure of 75 GPa. The data analysis of the extended fine structure reveals that the intramolecular distance first increases, reaching its maximum value at 25+/-5 GPa. From this value the intramolecular distance abruptly begins to decrease evidencing a nonpreviously observed phase transformation taking place at 25+/-5 GPa. A maximum variation of 0.08 A is observed at 65+/-5 GPa where again a phase transition occurs. This last transformation could correspond with the recently observed change to an incommensurate modulated phase. We discuss the possible generalization of the observed new phase transition at 25+/-5 GPa to the case of the other halogens.

Adaptive geometric numerical integration for point vortex dynamics.

In this paper we describe a variable stepsize integration method for the Hamiltonian dynamics of point vortices based on the explicit symplectic Zhang and Qin scheme. The adapted method is also explicit and preserves the reversible structure of the flow. In order to check the behavior of this adaptive method a numerical study of the exchange-scattering phenomenon in the three-vortex problem is made. The symmetry of the orbit and the energy evolution are discussed for the exchange-scattering model. A long-term integration of this and other models composed also of three vortices indicates that the adaptive Zhang-Qin method has good properties of efficiency and preservation of the first integrals associated with point vortex systems.

Radicales libres, antioxidantes y envejecimiento / Free radicals, antioxidants and aging

Recientemente ha aumentado el interés por el uso de antioxidantes para el tratamiento de enfermedades y la importancia del papel de los antioxidantes de la dieta en la prevención del desarrollo de algunas patologías. El envejacimiento, las alteraciones cardiovasculares, el cáncer, etc., parecen estar asociados a los procesos de oxidación que son el resultado de un exceso de moléculas reactivas. Hay acuerdo en considerar que el tiempo de vida de un organismo se encuentra en relación inversa a su tasa metabólica y por consiguiente a la tasa de daño oxidativo. Esto es consistente con que una gradual acumulación de las alteraciones genéticas perjudiciales debidas al daño oxidativo. Según Harman, los radicales libres producidos en el metabolismo del oxígeno provocan daño en las células, lo que conduce a alteraciones en el metabolismo. Según esta teoría, los antioxidantes celulares no son capaces de neutralizar las especies reactivas de oxígenos que se generan continuamente en la vida. Por ello, el envejecimiento celular está asociado a un estrés oxidativo crónico. En este trabajo se revisan las diferentes teorías que han ido apareciendo sobre el estrés oxidativo a lo largo de los últimos años y se glosa el papel y la importancia que tienen los antioxidantes en el desarrollo de enfermedades y el envejecimiento

Recently it is increased the interest by the use of antioxidants for the treatment of diseases ant the importance of the antioxidants contained in the diet ont he prevention of the development of some pathologies. Factors as the aging, the cardiovascular alterations and the cancer seemed to be associated with the oxidation processes that are the result of an excess of reactive molecules. There is agreement in considering that the lifetime of an organism is in inverse relationship with its metabolic rate and therefore with the rate of oxidative damage. This is consistent with a gradual accumulation of genetic alterations due to the oxidative damage. According to Harman, the free radicals deriving from the oxygen metabolism produce damage to the cells, what leads to alterations in the functions of the living systems. In line with this theory, antioxidants are not able to detoxify the reactive oxygen species that are generated continuously in the life. For that reason, the cellular aging is associated with chronic oxidative stress. In order to enhance the importance of the antioxidants in both development of diseases and aging, we carried out a review of the different theories that have been appearing on oxidative stress throughout the last years

Principales marcadores diagnósticos en la enfermedad de Alzheimer / Main biological parameters in the study of Alzheimer’disease

La enfermedad de Alzheimer afecta en el mundo a unas 25millones de personas, siendo la causa mas frecuente dedemencia en los paises occidentales. Su prevalencia va enaumento, debido al envejecimiento de la población. Por la edadde aparición la EA se puede clasificar en presenil ó de iniciotemprano si aparece antes de los 60-65 años y senil o de iniciotardio si aparece después.En esta revisión se estudian los principales parámetros biológicosa utilizar en la enfermedad de Alzheimer e intentar diferenciarlade otras patologías degenerativas, ya que el diagnosticoprecoz de la EA es de gran importancia.El gen Apo E esta localizado en el cromosoma humano 19 ycontiene 4 exones que codifica la apolipoproteina E de 299 aminoácidos.Las tres isoenzimas de la Apo E son la Apo E2, E3 yE4 y son productos de los tres alelos de cada locus génico. Tresfenotipos homozigoticos (apo E2/2, E3/3 y E4/4) y tres heterizigóticos(apo E3/2, E4/3 y E4/2) resultan de la expresión decada uno de los tres alelos. La sustitución de los aminoácidosen los codones 112 y 158 conllevan a las diferencias entre apoE2, E3 y E4.La presencia abundante de ambas placas seniles y marañasen el cerebro de pacientes con EA es el único criterio aceptadopara un diagnóstico inequivoco de esta patología. El mayorcomponente de las placas seniles es un péptido llamado betaamiloide.Este péptido se trata de un fragmento proteolítico deuna proteína precursora larga conocida como proteína precursoraamiloide (APP). Dado que este péptido es por tanto producidobajo condiciones normales su presencia no es especificade EA.Las marañas están compuestas por estructuras filamentosashelicoidales y su componente principal es una formafosforilada anormal del microtúbulo asociado a la proteínatau. Normalmente esta proteína tiene una presencia abundanteen las neuronas y sirve para estabilizar el microtúbuloen los axones. En el Alzheimer y particularmente en aquellasregiones del cerebro afectadas la proteína tau esta fosforiladade forma anormal conduciendo a un incremento en la cantidadde tau.Como la tau se trata de una proteína intracelular el nivelhallado en LCR es bajo. El desarrollo de una elevada afinidadpor los anticuerpos monoclonales altamente específicos para latau ha conducido al desarrollo de test para la detección de latau en LCR y un número elevado de pacientes con Alhzeimer ycontroles han mostrado una elevada expresión de la tau en lascélulas neuronales afectadas. Además los test basados en ladeterminación cuantitativa de la proteína tau en el LCR puedeser de gran ayuda en el diagnóstico de la EA.En la actualidad, el marcador en LCR que muestra mayorespecificidad es fosfo-tau. No obstante la determinación conjuntade los tres marcadores tau, fosfo-tau y AB42 en LCR,aumenta la especificidad y sensibilidad respecto a su utilizaciónindividual

Alzheimer´ disease (AD) affects in the World up to 25 millionpeople and it is the most common form of dementia amongolder people in the Western countries. The disease usuallybegins after age 60, and risk goes up with age. AD can be classifiedas of early beginning, if it appears before the 60-65 yearsand of late beginning, if it appears later.In this report, the main biological parameters in Alzheimer´disease are studied to try to differentiate it of other degenerativepathologies, since the precocious diagnose of the AD it isof great importance.The gene Apo E is located in the human chromosome 19 andit contains 4 exons that codes for the 299-amino acid proteinnamed Apolipoprotein (apo) E, that is genetically polymorphic.There are three common codominant alleles, designated E2(with a protective effect against AD), E3 (the predominant isoform)and E4 (which constitutes a major risk factor for AD) whosegenetic basis lies within codons 112 and 158 of the gene.The three common apo E alleles lead to six common phenotypes,three homozigotes (apo E2/2, E3/3 and E4/4) and threeheterozigotes (apo E3/2, E4/3 and E4/2), all originally disclosedby isoelectric focusing and immunoblotting.The abundant presence of both senile badges and tangles inthe brain of patient with AD is the only approach accepted foran unequivocal diagnosis of this pathology. The biggest componentin the senile badges is the called beta-amiloide peptide.This peptide is a proteolysis fragment of a protein well-knownlong precursor as amiloide protein precursor (APP). Since thispeptide is therefore taken place under normal conditions itspresence it is not it specific of AD.The tangles are composed by helicoidally filamentous structuresand their main component is a microtubule phosphoylatedabnormal form associated to the tau protein. This protein usuallyhas an abundant presence in the neurons and it is good to stabilizethe microtubule in the axons. In the AD and particularly in thoseregions of the affected brain, the tau protein is phosphorylatedin an abnormal way driving to an increment in the quantity of tau.As the tau it is a protein intracelular, decreased levels in the SCFshould be found. Nevertheless and by the reasons given in aboveparagraph, tau levels were increased in AD patients in comparisonwith healthy controls, especially in those having one or two Apo E4alleles. Therefore, the test based on the quantitative determinationof tau proteins in the CSF is of great help in the diagnosis of AD.At the present time, phospho-tau is the best marker. However,is not sensitive and specific enough to detect all the cases of AD.Therefore, the combination of Ab-42, phospho-tau and tau levelsin CSF should be used as a criteria to confirm or exclude AD

Micobacterias no tuberculosas (MNT): incidencia global, especies y valoración clínica de los aislamientos / Nontuberculous mycobacteria (NTM): overall incidence, species and isolates clinical assessment

Objetivo. Se revisa la incidencia de MNT aisladas en muestras biológicas de pacientes de nuestra área asistencial con objeto de conocer su frecuencia y hacer una valoración clínica de los hallazgos. Material y métodos. El período de estudio abarcó 12 años (1992-2003). Los métodos de procesamiento de las muestras fueron los convencionales (1992-1995) y a partir de 1995 se incorporó el sistema MB/BacTTM (BioMerieux). Para el frotis se empleó tinción fluorescente (auramina fenicada). La identificación de las micobacterias se realizó en el propio laboratorio o en el CNMV Carlos III de Madrid. Se utilizaron técnicas convencionales y sondas genéticas (Accuprobe®, BioMerieux). Para valorar la significación clínica de los hallazgos se siguieron los criterios internacionales. Resultados. En este período se procesaron 39.560 muestras, aislándose 2.484 micobacterias (6,3 por ciento), de las cuales 362 (14,6 por ciento) fueron MNT; las MNT correspondían a 245 pacientes. La procedencia de las muestras fue respiratoria (300), genitourinaria (40), adenopatía (7) y otros (15). La distribución de las especies fue: M. gordonae (95; 26,2 por ciento), M. fortuitum (70; 19,3 por ciento), M. avium complex (47; 13,0 por ciento), M. kansasii (20; 5,5 por ciento), M. aurum (13; 3,6 por ciento) y M. chelonae (10; 2,8 por ciento). La proporción de aislamientos de MNT con frotis positivo fue de 8,8 por ciento. Las especies con mayor indicencia de frotis positivos fueron M. avium complex (32 por ciento) y M. kansasii (35 por ciento). En relación con la evidencia de patología asociada en los pacientes, los resultados fueron: M. avium complex (20/20), M. kansasii (14/14), M. xenopi (8/8), M. serofulaceum (2/5), M. fortuitum (2/45), M. marinum (1/1). Conclusiones. 1) La incidencia de aislamientos de MNT ha sido similar a otras series de proyección nacional. 2) Existe una gran concordancia entre patología asociada y las especies M. avium complex, M. kansasii y M. xenopi. 3) La correlación frotis / cultivo fue superior en los aislamientos de M. avium complex y M. kansasii que en los restantes (AU)

Exceptional ideal strength of carbon clathrates.

We study by means of ab initio calculations the ideal tensile and shear strengths of the C-46 clathrate phase. While its bulk modulus and elastic constants are smaller than in diamond, its strength is found to be in all directions larger than the critical stresses associated with the diamond [111] planes of easy slip. This can be related to the frustration by the clathrate cage structure of the diamond to graphite instability under nonhydrostatic stress conditions [corrected] The criteria for designing strong materials are discussed.

Algunos aspectos de la anorexia nerviosa / Some aspects of the nervous anorexia

La anorexia nerviosa es un trastorno de origen psíquico que afecta a la conducta alimentaria y constituye un complejisimo cuadro compuesto de múltiples factores de todo orden que interactúan entre sí condicionándose o potenciándose. Estos pacientes presentan una serie de rasgos comunes, como son una baja autoestima, una valoración negativa de su aspecto personal, una actitud muy crítica en relación con su ingesta, una arraigada creencia en la falta de control sobre su peso y, sobre todo, la equiparación entre autocontrol y adelgazamiento. Se revisa la etipatogenia, los aspectos epidemiológicos, el cuadro clínico, el diagnóstico, las fases de la anorexia y los aspectos socioculturales y familiares. Por tanto, la anorexia nerviosa es un trastorno de la esfera oroalimenticia que afecta en la etapa adolescente fundamentalmente a las mujeres. Aunque la causa de esta patología es desconocida existe un nutrido grupo de factores que desencadenan y mantienen la enfermedad. El cuadro clínico afecta a numerosas funciones orgánicas entre las que destacamos la amenorrea. En cuanto a la recuperación de la enfermedad, destacamos la separación ambiental del paciente y así poder crear una situación de individuación (AU)

Arsénico en agua de bebida: un problema de salud pública / Arsenic in drinking water: a problem of public health

Revisamos el problema del arsénico en el agua de consumo, como problema de salud pública. La concentración de arsénico en el agua de consumo no debe ser superior al límite establecido de 50 microgramos/litro según la legislación vigente máxima en algunos países. El arsénico es un metaloide que se encuentra de manera natural ampliamente distribuido en la corteza terrestre. Es my ubicuo y está presente en cantidades ínfimas en todo tipo de rocas, suelos, agua y aire. El arsénico puede existir en cuatro estados de valencia: (3, 0, +3 y +S). Se distribuye extensamente en el agua superficial y subterránea. Las concentraciones de arsénico en aguas son muy variables, generalmente bajas, pudiendo existir concentraciones altas de forma natural o como consecuencia de la actividad humana. La mayoría de las zonas con altos niveles de arsénico son resultado de procesos naturales. Los distintos problemas de arsénico en aguas subterráneas ocurren tanto bajo condiciones reducidas como oxidantes, y también en ambientes húmedos y secos. La gente puede estar expuesta al arsénico por muchas vías diferentes. En intentos de suicidio y homicidio ocurren altos niveles de exposición por ingestión. También pueden ocurrir altas exposiciones por largos períodos de tiempo en algunos puestos de trabajo a través de la inhalación -o ingestión de polvo. El arsénico ha estado desde hace mucho tiempo asociado con efectos tóxicos, produciendo marcados impactos sobre la salud, tras exposición oral o inhalación, que van desde la muerte aguda a efectos crónicos como cáncer y enfennedades del sistema vascular. Los niveles de arsénico o de sus metabolitos en la sangre, el pelo, las uñas y la orina se utilizan como biomarcadores de la exposición al arsénico. Por tanto, el arsénico en el agua de bebida supone un importante problema de Salud Pública, que debe ser tenido en cuenta en nuestro entorno, debe ser conocido en sus diferentes aspectos por el personal sanitario relacionado con la Salud Pública y sobre el que debe hacerse una vigilancia periódica. (AU)

Clinical evaluation of a commercial ligase-based gene amplification method for detection of Mycobacterium tuberculosis.

The purpose of this study was to evaluate the clinical usefulness of a commercial ligase-based gene amplification method (LCx Mycobacterium tuberculosis test; Abbott Laboratories, USA) for detection of Mycobacterium tuberculosis. The tuberculosis infection rate among clinical samples was 10.6%. The sensitivity, specificity, and positive and negative predictive values were 23.5%, 100%, 100%, and 91.7%, respectively, with the fluorochrome auramine stain; 32.4%, 100%, 100%, and 92.6%, respectively, with culture; and 76.5%, 95.8%, 68.4% and 97.2%, respectively, with the gene amplification method. When only samples from patients without current or previous treatment were studied, the sensitivity was 36.4% with the auramine stain, 63.6% with culture, and 100% with the gene amplification assay. The mean treatment time for culture-negative and assay-negative samples was greater than that of culture-negative and assay-positive samples. The LCx Mycobacterium tuberculosis test is a sensitive method for detection and identification of Mycobacterium tuberculosis. It produces few false-positive results. However, as it can remain positive after the culture becomes negative, it is not recommended for evaluation of treatment efficiency.

[Genotypes of hepatitis C virus: their relationship with risk factors, the severity of liver disease, and the serologic response]. / Genotipos del virus de la hepatitis C: relación con los factores de riesgo, con la gravedad de la enfermedad hepática y con la respuesta serológica.

BACKGROUND: The objective of our study was to ascertain the prevalence of different HCV genotypes between the hepatitis C patients in the health area of Monforte de Lemos, Spain, as well as the possible influence of risk factors on their distribution and their relation with hepatic disease and with the serologic response. PATIENTS AND METHODS: We have studied 128 patients with hepatitis C. Of these, 41 were intravenous drug users (IVDU), 19 had received transfusions, 7 were hemodialyzed and in 61 the risk factors were unknown. Antibodies against HCV were detected by second-generation enzyme immunoassay (EIA) and confirmed by immunoblot. RNA-HCV presence was studied by reverse transcription-PCR (RT-PCR), and a reverse hybridization test of the amplifications was used for the genotyping. RESULTS: Hepatitis C genotypes 1b (46.1 [8.6%]), 1a (23.4 [7.3%]) and 3a (13.3 [5.9%]) were the most frequently encountered genotype. Genotype 1a (48.8 [15.3%]) was the most prevalent genotypes in IVDU patients, while 1b was the most frequent in patients of unknown risk factors (62.3 [12.1%]). Alanine-aminotransferase (ALT) was elevated in 66.6 (17.7%) of patients with genotype 1a, in 87.5 (8.6%) of patients with genotype 1b (p = 0.0367) and in 94.1 (11.2%) of patients with genotype 3a (p = 0.0347). Subtype 1b was present in 6 of 7 cases of cirrhosis (85.7%) and in 7 of 12 cases of active chronic hepatitis (58.3%). No significant statistical differences were observed between the genotypes and the specific IgM response against core antigen of HCV, neither we observed differences in the serologic response against C1, C2, NS3 and NS4 peptides. CONCLUSIONS: Hepatitis C genotypes 1a and 3a were the most prevalent genotypes between IVDU patients while genotype 1b was the most frequent between non-IVDU patients. Genotype 1b was associated to severe liver disease. Percentage of positivity or the reactivity against HCV peptides was independent of the genotype encountered in the patient.

[Variants of hepatitis C virus in different risk groups. Comparative study of a method for genotyping and another for serotyping]. / Variantes del virus de la hepatitis C en diferentes grupos de riesgo. Estudio comparativo de un método de genotipificación y otro de serotipificación.

AIMS: The aim of this study was to know the prevalence of the different variants of HCV in the Health Care area of Monforte de Lemos (Lugo, Spain) and its distribution according to risk factors and to compare the results obtained with one genotyping and one serotyping technique. PATIENTS AND METHODS: Eighty-four patients with hepatitis C were studied, 25 of whom were IVDA, 14 had received blood transfusions, 4 hemodialysis and the risk factor was unknown in 41. The antibodies against HCV were studied by second generation EIA and confirmed by an immunoblot technique. Serotyping was carried out by an ELISA test. Genotyping was undertaken with a reverse hybridation test of the amplification obtained by polymerase chain reaction prior to reverse transcription (RT-PCR). RESULTS AND CONCLUSIONS: The genotypes most frequently observed were 1b (47.6%), 1a (20.2%) and 3 (14.3%). In the IVDA patients the genotypes 1a (40%) and 3 (24%) predominated. The 1b genotype was the most prevalent in the patients of unknown risk (68.3%) and patients with a history of blood transfusion (50%). The prevalence of the different serotypes was similar to that of the corresponding genotypes, with nearly 100% agreement. The number of untypable cases was greater in the serotyping technique (20.2%) than in the genotyping (2.4%). A greater number of mixed infections was detected with serotyping (7 cases, 8.3%) than with genotyping (1 case, 1.2%). Lesser sensitivity of the serotyping test was observed in the patients lacking anti-NS4 antibodies.

Nanosecond-resolved XMCD on ID24 at the ESRF to investigate the element-selective dynamics of magnetization switching of Gd-Co amorphous thin film.

The one-bunch filling mode of the ESRF is combined with a microcoil to generate a pulsed-magnetic-field pump phased with respect to the probe that is given by the bunch of photons emitted each turn (357 kHz). Nanosecond-resolved X-ray magnetic circular dichroism (XMCD) is carried out. Besides the microcoil, the two other key-elements are the energy-dispersive XAS spectrometer, which yields parallel data acquisition, and the diamond-based quarter-wave plate, which tunes the helicity of the photon alternatively left and right.