Monte Carlo simulation of near-field terahertz emission from semiconductors

We simulated the carrier dynamics in InGaAs after ultrafast photoexcitation. By using a finite-difference time-domain approach we were able to analyze the near terahertz field emission caused by the motion of such carriers. We found that both the current parallel and normal to the interface take a relevant role in the terahertz emission. We also found that the ballistic motion of the carriers after photoexcitation dominates the emission rather than diffusion

Citología de cuello uterino e impeditividad eléctrica en la detección temprana del cáncer cervical

RESUMENSe reportan los resultados de un estudio piloto de las propiedades eléctricas del tejido epitelial de cuello uterino por medio de espectroscopia de impeditividad eléctrica, con el propósito de estudiar la detección temprana de la neoplasia intraepitelial con éste método. Para ello, se midieron 636 espectros de impeditividad eléctrica en 53 pacientes de la Liga Santandereana de Lucha Contra el Cáncer, los cuales fueron comparados con las citologías cervicales.  Los datos experimentales fueron ajustados al modelo de Cole-Cole con una herramienta computacional basada en algoritmos genéticos. Los resultados del estudio realizado sugieren una sensibilidad y especificidad superiores al 70%.Salud UIS 2012; 44 (2): 15-19Palabras clave: Espectroscopia de Impeditividad Eléctrica, Neoplasia Intraepitelial Cervical, Citología Cervical, Detección de Cáncer.ABSTRACTAre reported the results of a study about the properties of cervical epitelial tissue using electrical impeditivity spectroscopy, with the objective of studying the early detection of intraepithelial neoplasia, with this metled. 636 impedivity  spectrums from 53 patients at Liga Santandereana de Lucha contra el cancer were measured and compared with cervical cytology.  Experimental data were felted to the Cole-Cole model, using a computational tool based in genetic algorithms.  The results of the study suggest a sensibility and specificity above 70%.  Salud UIS 2012; 44 (2): 15-19Keywords: Electrical Impeditivity Spectroscopy, Cervical Intraepithelial Neoplasia, Cancer Detection

Photoelectrocatalytic degradation of 2,4-dichlorophenol in a TiO2 nanotube-coated disc flow reactor

Photoelectrocatalytic (PEC) water treatment is a promising technology for organic pollution abatement. Much of the prior research focused on material discovery and optimization. However, challenges exist in scaling-up PEC processes and are associated with designing reactors with effective light irradiation on electrode surfaces and, simultaneously, efficient electrode configurations. We design and demonstrate key reactor design principles, which influence reaction mechanisms, for a reactor using a TiO2 nanotube-coated disc flow reactor. Degradation of organochlorinated 2,4-dichlorophenol was studied as representative carcinogenic micropollutant. The synergistic photoelectrocatalytic process showed 5-fold faster degradation kinetics than solely electrocatalytic treatment or a greater than 2-fold enhancement over photocatalysis alone. Applicability of photoelectrocatalytic treatment was demonstrated over a wide range of micropollutant concentrations with almost complete abatement even at concentrations up to 25 mg L-1 of 2,4-dichlorophenol. Mechanistically, the increase in applied current density efficiency for degradation of 2,4-dichlorophenol was due to stabilization of charge carriers and higher oxidants production rates in the PEC system. Carboxylic acids were identified as the main by-products formed from cleavage of the phenolic ring moieties in 2,4-dichlorophenol. However, very importantly we achieved dehalogenation photoelectrocatalysis with evidence of chlorine heteroatoms released as innocuous chloride anions. Overall, this research demonstrates the importance of PEC reactor design and how properly orientated TiO2 nanotube-coated disc flow reactors leverage both novel material designs and reactor architectures to achieve pollutant degradation

Quality control of leather by terahertz time domain spectroscopy

We use terahertz time-domain spectroscopy combined with effective-medium theory to measure moisture content and thickness of leather simultaneously. These results demonstrate that this method could become a standard quality control test for the industrial tanning process

Charcoal obtained from cherry stones in different carbonization atmospheres

The exploitation of using agro-industrial residues as the cherry stone to produce charcoal and activated carbon is very relevant nowadays due to the high demand of these materials and their environmental advantages. This work describes the methods to prepare charcoal from cherry stones (CS) using final heating temperature of 600 °C, with or without the application of an equal flow of nitrogen or air. The isothermal time has been of 2 hours, an adequate time to study carbonisation by varying the atmosphere. The charcoal obtained has the appropriate characteristics as precursors of activated carbon. Of the three samples prepared in different atmospheres, *N, N∼ and AN, the third is an activated carbon. It is evidenced that the yield in material carbonaceous is somewhat lower when applying the nitrogen current and approximately 5% less when applying the air current. For the different samples, in this work we have studied the effects of the atmosphere during the heat treatment of CS, the yield, the chemical composition and the structure, as well as the pore structure of the same

Ventilatory threshold concordance between ergoespirometry and heart rate variability in female professional cyclists

The ventilatory threshold (VT) is the point at which ventilation intensifies disproportionately concerning to the oxygen uptake, this parameter is essential within the training methodology to optimize performance; the purpose of this work is to measure the degree of agreement between the determination of the ventilatory threshold determined by for oxygen uptake and four methods by Heart Rate Variability (HRV). Methodology: Twelve professional female cyclists between 18 and 28 years of age were evaluated through a maximal incremental test on a cycle ergometer; gas exchange was measure with a portable telemetric device (Cosmed K4b2®) and simultaneously the HRV was registered by R-R recording trough a Polar RS800CX® (Polar, Finland) heart rate monitor. Statistics: The degree of precision and accuracy established between the variables mentioned and normality test Shapiro-Wilk. Results: rho = 1.00 with p-value < .05, and Lin correlation and concordance coefficients of .99 with r = 0.98 for ventilatory threshold 2 (VT2), constituting a level of precision and accuracy almost perfect; by contrast, ventilatory threshold 1 (VT1) did not show significant precision and accuracy. This study suggests that VT2 can be identified from The time series. RR using the analysis of frequency and temporal domains likewise allows. Us to have a reference measure for future research in other sports.The project was funded through the internal of the Institución Universitaria Escuela Nacional del Deporte

Generalidades de la farmacovigilancia, su importancia y el quehacer del regente

Dentro de la relación paciente medicamento la farmacovigilancia juega un papel fundamental; es un sistema de compromiso sanitario, por medio del cual se conoce el uso adecuado, racional y seguro de los medicamentos, como para evaluar sus riesgos y sus beneficios. Se considera importante aclarar que se encarga de recoger, vigilar, investigar y evaluar, la evaluación sobre los efectos adversos de los medicamentos según la normatividad vigente; permitir la interrelación entre pacientes, médicos tratantes, clinicas, hospitales, secretarias de salud y laboratorios farmacéuticos, quienes conforman la red nacional de Framacovigilancia, entes que se encargan de mantener la información al día sobre lo referente a problemas de seguridad en el uso correcto de medicamentos, para de esta manera promover la educacion continua y el entrenamiento clínico en farmacovigilancia. Las actividades en farmacovigilancia, se puede realizar desde diversos métodos, con le objetivo de reportar cualquier evento adverso, relacionado con los medicamentos, vacunas, productos homeopáticos, los cuales deben ser prescrito o dispensado por el servicio farmacéutico.Within the patient drug relationship pharmacovigilance plays a fundamental role; it is a system of health commitment, through which the proper, rational and safe use of medicines is known, as to evaluate their risks and their benefits. It is considered important to clarify that it is responsible for collecting, monitoring, investigating and evaluating the evaluation of the adverse effects of medicines according to current regulations; to allow the interrelation between patients, treating physicians, clinica, hospitals, health secretaries and pharmaceutical laboratories, who make up the national network of Framacovigilancia, entities that are responsible for keeping up-to-date information on problems related to the safety or correct use of medicines, promoting continuous education and clinical training in pharmacovigilance. The development of pharmacovigilance activities, can be carried out by different methods, what should be reported is any adverse event, related to medicines, vaccines, homeopathic products, which must be prescribed or dispensed by the pharmaceutical service

Abnormalities of hydrogen sulfide and glutathione pathways in mitochondrial dysfunction

This work was supported by NIH P01 HD080642 (CMQ), and Ministerio de Ciencia e inn (LCL). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Background Mitochondrial disorders are genetic diseases for which therapy remains woefully inadequate. Therapy of these disorders is particularly challenging partially due to the heterogeneity and tissue-specificity of pathomechanisms involved in these disorders. Abnormalities in hydrogen sulfide (H2S) metabolism are emerging as novel mechanism in mitochondrial dysfunction. However, further studies are necessary to understand the effects, protective or detrimental, of these abnormalities, and their relevance, in mitochondrial diseases. Aim of Review: To review the recent evidences of derangement of the metabolism of H2S, at biosynthesis or oxidation levels, in mitochondrial dysfunction, focusing specifically on the alterations of H2S oxidation caused by primary Coenzyme Q (CoQ) deficiency. Key Scientific Concepts of Review: Mitochondria play a key role in the regulation of H2S and GSH metabolism pathways. However, further studies are needed to understand the consequences of abnormalities of H2S and GSH synthesis on the oxidation pathway, and vice versa; and on the levels of H2S and GSH, their tissue-specific detrimental effects, and their role the role in mitochondrial diseases. Beside the known H2S pathways, additional, tissue-specific, enzymatic systems, involved in H2S production and elimination, might exist.United States Department of Health & Human Services National Institutes of Health (NIH) - USA P01 HD080642Ministerio de Ciencia e inn (LCL

The transcription factor LEF1 interacts with NFIX and switches isoforms during adult hippocampal neural stem cell quiescence

Stem cells in adult mammalian tissues are held in a reversible resting state, known as quiescence, for prolonged periods of time. Recent studies have greatly increased our understanding of the epigenetic and transcriptional landscapes that underlie stem cell quiescence. However, the transcription factor code that actively maintains the quiescence program remains poorly defined. Similarly, alternative splicing events affecting transcription factors in stem cell quiescence have been overlooked. Here we show that the transcription factor T-cell factor/lymphoid enhancer factor LEF1, a central player in canonical beta-catenin-dependent Wnt signalling, undergoes alternative splicing and switches isoforms in quiescent neural stem cells. We found that active beta-catenin and its partner LEF1 accumulated in quiescent hippocampal neural stem and progenitor cell (Q-NSPC) cultures. Accordingly, Q-NSPCs showed enhanced TCF/LEF1-driven transcription and a basal Wnt activity that conferred a functional advantage to the cultured cells in a Wnt-dependent assay. At a mechanistic level, we found a fine regulation of Lef1 gene expression. The coordinate upregulation of Lef1 transcription and retention of alternative spliced exon 6 (E6) led to the accumulation of a full-length protein isoform (LEF1-FL) that displayed increased stability in the quiescent state. Prospectively isolated GLAST + cells from the postnatal hippocampus also underwent E6 retention at the time quiescence is established in vivo. Interestingly, LEF1 motif was enriched in quiescence-associated enhancers of genes upregulated in Q-NSPCs and quiescence-related NFIX transcription factor motifs flanked the LEF1 binding sites. We further show that LEF1 interacts with NFIX and identify putative LEF1/NFIX targets. Together, our results uncover an unexpected role for LEF1 in gene regulation in quiescent NSPCs, and highlight alternative splicing as a post-transcriptional regulatory mechanism in the transition from stem cell activation to quiescence.Peer reviewe