Synthesis, morphology, optical and photocatalytic performance of nanostructured beta-Ga2O3

Fine powders of beta-Ga2O3 nanostructures were prepared via low temperature reflux condensation method by varying the pH value without using any surfactant. The pH value of reaction mixture had great influence on the morphology of final products. High crystalline single phase beta-Ga2O3 nanostructures were obtained by thermal treatment at 900 degrees C which was confirmed by X-ray diffraction and Raman spectroscopy. The morphological analysis revealed rod like nanostructures at lower and higher pH values of 6 and 10, while spindle like structures were obtained at pH = 8. The phase purity and presence of vibrational bands were identified using Fourier transform infrared spectroscopy. The optical absorbance spectrum showed intense absorption features in the UV spectral region. A broad blue emission peak centered at 441 nm due to donor-acceptor gallium-oxygen vacancy pair recombination appeared. The photocatalytic activity toward Rhodamine B under visible light irradiation was higher for nanorods at pH 10.

CXI-benzo-84 reversibly binds to tubulin at colchicine site and induces apoptosis in cancer cells

Here, we have discovered CXI-benzo-84 as a potential anticancer agent from a library of benzimidazole derivatives using cell based screening strategy. CXI-benzo-84 inhibited cell cycle progression in metaphase stage of mitosis and accumulated spindle assembly checkpoint proteins Mad2 and BubR1 on kinetochores, which subsequently activated apoptotic cell death in cancer cells. CXI-benzo-84 depolymerized both interphase and mitotic microtubules, perturbed EB1 binding to microtubules and inhibited the assembly and GTPase activity of tubulin in vitro. CXI-benzo-84 bound to tubulin at a single binding site with a dissociation constant of 1.2 +/- 0.2 mu M. Competition experiments and molecular docking suggested that CXI-benzo-84 binds to tubulin at the colchicine-site. Further, computational analysis provided a significant insight on the binding site of CXI-benzo-84 on tubulin. In addition to its potential use in cancer chemotherapy, CXI-benzo-84 may also be useful to screen colchicine-site agents and to understand the colchicine binding site on tubulin. (C) 2013 Elsevier Inc. All rights reserved.

A model for the classification and survey of clock synchronization protocols in WSNs

Clock synchronization in wireless sensor networks (WSNs) assures that sensor nodes have the same reference clock time. This is necessary not only for various WSN applications but also for many system level protocols for WSNs such as MAC protocols, and protocols for sleep scheduling of sensor nodes. Clock value of a node at a particular instant of time depends on its initial value and the frequency of the crystal oscillator used in the sensor node. The frequency of the crystal oscillator varies from node to node, and may also change over time depending upon many factors like temperature, humidity, etc. As a result, clock values of different sensor nodes diverge from each other and also from the real time clock, and hence, there is a requirement for clock synchronization in WSNs. Consequently, many clock synchronization protocols for WSNs have been proposed in the recent past. These protocols differ from each other considerably, and so, there is a need to understand them using a common platform. Towards this goal, this survey paper categorizes the features of clock synchronization protocols for WSNs into three types, viz, structural features, technical features, and global objective features. Each of these categories has different options to further segregate the features for better understanding. The features of clock synchronization protocols that have been used in this survey include all the features which have been used in existing surveys as well as new features such as how the clock value is propagated, when the clock value is propagated, and when the physical clock is updated, which are required for better understanding of the clock synchronization protocols in WSNs in a systematic way. This paper also gives a brief description of a few basic clock synchronization protocols for WSNs, and shows how these protocols fit into the above classification criteria. In addition, the recent clock synchronization protocols for WSNs, which are based on the above basic clock synchronization protocols, are also given alongside the corresponding basic clock synchronization protocols. Indeed, the proposed model for characterizing the clock synchronization protocols in WSNs can be used not only for analyzing the existing protocols but also for designing new clock synchronization protocols. (C) 2014 Elsevier B.V. All rights reserved.

Numerical analysis of segmented-electrode Orbitraps

Simple geometries which are possible alternatives for the Orbitrap are studied in this paper. We have taken up for numerical investigation two segmented-electrode structures, ORB1 and ORB2, to mimic the electric field of the Orbitrap. In the ORB1, the inner spindle-like electrode and the outer barrel-like electrode of the Orbitrap have been replaced by 35 rings and 35 discs of fixed radii, respectively. In this structure two segmented end cap electrodes have been added. In this geometry, different potentials are applied to the different electrodes keeping top-bottom symmetry intact. In the second geometry, ORB2, the inner and outer electrodes of the Orbitrap were replaced by an approximate step structure which follows the profile of the Orbitrap electrodes. In the present study 45 steps have been used. In the ORB2, like the Orbitrap, the inner electrode is held at a negative potential and the outer electrode is at ground potential. For the purpose of comparing the performance of ORB1 and ORB2 with that of the Orbitrap, the following studies have been undertaken: (1) variation of electric potential, (2) computation of ion trajectories, (3) simulation of image currents. These studies have been carried out using both 2D and 3D Boundary Element Method (BEM), the 3D BEM was developed specifically for this study. It has been seen in these investigations that ORB1 and ORB2 have performance similar to that of the Orbitrap, with the performance of the ORB1 being seen to be marginally superior to that of the ORB2. It has been shown that with proper optimization, geometries containing far fewer electrodes can be used as mass analyzers. A novel technique of optimization of the electric field has been proposed with the objective of minimizing the dependence of axial frequency of ion motion on the initial position of an ion. The results on the optimization of 9 and 15 segmented-electrode traps having the same design as ORB1 show that it can provide accurate mass analysis. (C) 2015 Elsevier B.V. All rights reserved.

Numerical analysis of segmented-electrode Orbitraps

Simple geometries which are possible alternatives for the Orbitrap are studied in this paper. We have taken up for numerical investigation two segmented-electrode structures, ORB1 and ORB2, to mimic the electric field of the Orbitrap. In the ORB1, the inner spindle-like electrode and the outer barrel-like electrode of the Orbitrap have been replaced by 35 rings and 35 discs of fixed radii, respectively. In this structure two segmented end cap electrodes have been added. In this geometry, different potentials are applied to the different electrodes keeping top-bottom symmetry intact. In the second geometry, ORB2, the inner and outer electrodes of the Orbitrap were replaced by an approximate step structure which follows the profile of the Orbitrap electrodes. In the present study 45 steps have been used. In the ORB2, like the Orbitrap, the inner electrode is held at a negative potential and the outer electrode is at ground potential. For the purpose of comparing the performance of ORB1 and ORB2 with that of the Orbitrap, the following studies have been undertaken: (1) variation of electric potential, (2) computation of ion trajectories, (3) simulation of image currents. These studies have been carried out using both 2D and 3D Boundary Element Method (BEM), the 3D BEM was developed specifically for this study. It has been seen in these investigations that ORB1 and ORB2 have performance similar to that of the Orbitrap, with the performance of the ORB1 being seen to be marginally superior to that of the ORB2. It has been shown that with proper optimization, geometries containing far fewer electrodes can be used as mass analyzers. A novel technique of optimization of the electric field has been proposed with the objective of minimizing the dependence of axial frequency of ion motion on the initial position of an ion. The results on the optimization of 9 and 15 segmented-electrode traps having the same design as ORB1 show that it can provide accurate mass analysis. (C) 2015 Elsevier B.V. All rights reserved.

Del sueño cartesiano a la muerte encefálica

Resumen: Entre el sueño y la muerte hay “sólo una distancia”. El dormir encierra un misterio que se aviva con los sueños y, al parecer, habrían prefigurado al mismo método científico moderno. Descartes pensó que en sus sueños se transmitía el espíritu de la verdad. El alma soñadora e inmortal adquirió notoriedad en su dualismo, al tiempo que dejó de asociársela con la muerte. Tres siglos después, la medicina permitió identificar individuos que estaban muertos, aunque pareciesen dormidos (coma dépassé). Así reapareció la asociación sueño-muerte, pero ahora con médicos provistos del “diagnóstico anátomo-clínico” que, por su herencia cartesiana, demandará evidencias. La duda metódica integrada al pensamiento científico, aportaría incertidumbre a las formulaciones cerebrales de la muerte. Este trabajo repasa el valor de los sueños para el pensamiento occidental, busca al “hombre-máquina” dentro de los criterios neurológicos del fallecido y, con la ayuda de la Filosofía, intenta comprender algunas objeciones en torno a la licitud del diagnóstico de “muerte encefálica”. Se propone una revisión sucinta de la obra del filósofo francés y su reflejo en aspectos del debate ofrecido por la literatura médica.

Factors associated with chronic pain in patients with bipolar depression: a cross-sectional study

Background: While pain is frequently associated with unipolar depression, few studies have investigated the link between pain and bipolar depression. In the present study we estimated the prevalence and characteristics of pain among patients with bipolar depression treated by psychiatrists in their regular clinical practice. The study was designed to identify factors associated with the manifestation of pain in these patients.- Methods:Patients diagnosed with bipolar disorder (n=121) were selected to participate in a cross-sectional study in which DSM-IV-TR criteria were employed to identify depressive episodes. The patients were asked to describe any pain experienced during the study, and in the 6 weeks beforehand, by means of a Visual Analogical Scale (VAS).- Results: Over half of the bipolar depressed patients (51.2%, 95% CI: 41.9%–60.6%), and 2/3 of the female experienced concomitant pain. The pain was of moderate to severe intensity and prolonged duration, and it occurred at multiple sites, significantly limiting the patient’s everyday activities. The most important factors associated with the presence of pain were older age, sleep disorders and delayed diagnosis of bipolar disorder.- Conclusions: Chronic pain is common in bipolar depressed patients, and it is related to sleep disorders and delayed diagnosis of their disorder. More attention should be paid to study the presence of pain in bipolar depressed patients, in order to achieve more accurate diagnoses and to provide better treatment options.

Evaluar la calidad de vida de los cuidadores en enfermos de Alzheimer

[ES]Los cambios sociodemográficos y el aumento de la esperanza de vida han dado lugar a un aumento de algunas enfermedades, incluyendo la enfermedad de Alzheimer. La enfermedad de Alzheimer no sólo afecta a la persona que padece dicha enfermedad, sino que también repercute en la familia. Los cuidadores familiares son los que, de manera mayoritaria, se hacen cargo de la atención de estos pacientes con un compromiso de 24 horas, con lo que implica hacer cambios en sus estilos de vida. Los objetivos de este estudio son describir las características socio-demográficas, determinar la sobrecarga de los cuidadores informales y evaluar la calidad de sueño de los cuidadores. Se realizará un estudio transversal que incluirá a 40 cuidadores de enfermos de Alzheimer, seleccionados por un muestreo no probabilístico de selección por cuotas. Los participantes serán los cuidadores informales de pacientes con la enfermedad de Alzheimer que estén en el estadío III o IV de dicha enfermedad. Nuestra variable dependiente será el sueño y como variable independiente la sobrecarga. El estudio se realizará en la asociación de familiares de Alzheimer de Bilbao (A.F.A - Bizkaia), dónde se captará a la muestra de estudio y donde se procederá a aplicar los cuestionarios pertinentes para dicho estudio. Para participar en el estudio es necesario que firmen el consentimiento informado. Los instrumentos que se utilizarán son el cuestionario de Pittsburg que evalúa la calidad de sueño y la escala de carga de Zarit. Para el análisis de datos se utilizará el programa SPSS 15.0. Palabras clave: enfermedad de Alzheimer, cuidadores, cuidadores familiares, demencia, sobrecarga, sueño.

Studying conscious and unconscious vision with functional Magnetic Resonance Imaging : the BOLD promise

Waking up from a dreamless sleep, I open my eyes, recognize my wife’s face and am filled with joy. In this thesis, I used functional Magnetic Resonance Imaging (fMRI) to gain insights into the mechanisms involved in this seemingly simple daily occurrence, which poses at least three great challenges to neuroscience: how does conscious experience arise from the activity of the brain? How does the brain process visual input to the point of recognizing individual faces? How does the brain store semantic knowledge about people that we know? To start tackling the first question, I studied the neural correlates of unconscious processing of invisible faces. I was unable to image significant activations related to the processing of completely invisible faces, despite existing reports in the literature. I thus moved on to the next question and studied how recognition of a familiar person was achieved in the brain; I focused on finding invariant representations of person identity – representations that would be activated any time we think of a familiar person, read their name, see their picture, hear them talk, etc. There again, I could not find significant evidence for such representations with fMRI, even in regions where they had previously been found with single unit recordings in human patients (the Jennifer Aniston neurons). Faced with these null outcomes, the scope of my investigations eventually turned back towards the technique that I had been using, fMRI, and the recently praised analytical tools that I had been trusting, Multivariate Pattern Analysis. After a mostly disappointing attempt at replicating a strong single unit finding of a categorical response to animals in the right human amygdala with fMRI, I put fMRI decoding to an ultimate test with a unique dataset acquired in the macaque monkey. There I showed a dissociation between the ability of fMRI to pick up face viewpoint information and its inability to pick up face identity information, which I mostly traced back to the poor clustering of identity selective units. Though fMRI decoding is a powerful new analytical tool, it does not rid fMRI of its inherent limitations as a hemodynamics-based measure.

Neuronal mechanism of state control in Drosophila melanogaster

The changes in internal states, such as fear, hunger and sleep affect behavioral responses in animals. In most of the cases, these state-dependent influences are “pleiotropic”: one state affects multiple sensory modalities and behaviors; “scalable”: the strengths and choices of such modulations differ depending on the imminence of demands; and “persistent”: once the state is switched on the effects last even after the internal demands are off. These prominent features of state-control enable animals to adjust their behavioral responses depending on their internal demands. Here, we studied the neuronal mechanisms of state-controls by investigating energy-deprived state (hunger state) and social-deprived state of fruit flies, Drosophila melanogaster, as prototypic models. To approach these questions, we developed two novel methods: a genetically based method to map sites of neuromodulation in the brain and optogenetic tools in Drosophila.

These methods, and genetic perturbations, reveal that the effect of hunger to alter behavioral sensitivity to gustatory cues is mediate by two distinct neuromodulatory pathways. The neuropeptide F (NPF) – dopamine (DA) pathway increases sugar sensitivity under mild starvation, while the adipokinetic hormone (AKH)- short neuropeptide F (sNPF) pathway decreases bitter sensitivity under severe starvation. These two pathways are recruited under different levels of energy demands without any cross interaction. Effects of both of the pathways are mediated by modulation of the gustatory sensory neurons, which reinforce the concept that sensory neurons constitute an important locus for state-dependent control of behaviors. Our data suggests that multiple independent neuromodulatory pathways are underlying pleiotropic and scalable effects of the hunger state.

In addition, using optogenetic tool, we show that the neural control of male courtship song can be separated into probabilistic/biasing, and deterministic/command-like components. The former, but not the latter, neurons are subject to functional modulation by social experience, supporting the idea that they constitute a locus of state-dependent influence. Interestingly, moreover, brief activation of the former, but not the latter, neurons trigger persistent behavioral response for more than 10 min. Altogether, these findings and new tools described in this dissertation offer new entry points for future researchers to understand the neuronal mechanism of state control.

Biophysical and network mechanisms of high frequency extracellular potentials in the rat hippocampus

A fundamental question in neuroscience is how distributed networks of neurons communicate and coordinate dynamically and specifically. Several models propose that oscillating local networks can transiently couple to each other through phase-locked firing. Coherent local field potentials (LFP) between synaptically connected regions is often presented as evidence for such coupling. The physiological correlates of LFP signals depend on many anatomical and physiological factors, however, and how the underlying neural processes collectively generate features of different spatiotemporal scales is poorly understood. High frequency oscillations in the hippocampus, including gamma rhythms (30-100 Hz) that are organized by the theta oscillations (5-10 Hz) during active exploration and REM sleep, as well as sharp wave-ripples (SWRs, 140-200 Hz) during immobility or slow wave sleep, have each been associated with various aspects of learning and memory. Deciphering their physiology and functional consequences is crucial to understanding the operation of the hippocampal network.

We investigated the origins and coordination of high frequency LFPs in the hippocampo-entorhinal network using both biophysical models and analyses of large-scale recordings in behaving and sleeping rats. We found that the synchronization of pyramidal cell spikes substantially shapes, or even dominates, the electrical signature of SWRs in area CA1 of the hippocampus. The precise mechanisms coordinating this synchrony are still unresolved, but they appear to also affect CA1 activity during theta oscillations. The input to CA1, which often arrives in the form of gamma-frequency waves of activity from area CA3 and layer 3 of entorhinal cortex (EC3), did not strongly influence the timing of CA1 pyramidal cells. Rather, our data are more consistent with local network interactions governing pyramidal cells' spike timing during the integration of their inputs. Furthermore, the relative timing of input from EC3 and CA3 during the theta cycle matched that found in previous work to engage mechanisms for synapse modification and active dendritic processes. Our work demonstrates how local networks interact with upstream inputs to generate a coordinated hippocampal output during behavior and sleep, in the form of theta-gamma coupling and SWRs.

Condições de trabalho de ambiente cirúrgico e a saúde dos trabalhadores de enfermagem

O Centro Cirúrgico é um serviço especializado com estrutura física e organizacional complexa, normas e rotinas rigorosas, intensa atividade técnica, aparato tecnológico que requer profissionais treinados. A pesquisa teve como objeto de estudo os fatores de riscos ocupacionais e os problemas de saúde decorrentes do trabalho, identificados pelos profissionais de enfermagem de um Centro Cirúrgico de um Hospital Universitário da cidade do Rio de Janeiro. Os objetivos foram: analisar os fatores de riscos ocupacionais que possibilitam o aparecimento de problemas de saúde nos profissionais de enfermagem do Centro Cirúrgico segundo esses trabalhadores; descrever as características sociodemográficas dos profissionais lotados no Centro Cirúrgico; levantar os fatores de risco do ambiente cirúrgico identificados pelos trabalhadores de enfermagem do Centro Cirúrgico de um Hospital Universitário; e, discutir a relação entre os riscos do ambiente de trabalho e os problemas de saúde autoreferidos por trabalhadores de enfermagem do Centro Cirúrgico. A metodologia usada foi uma pesquisa não-experimental, de natureza descritiva, com abordagem quantitativa, desenvolvida em um centro cirúrgico de um hospital universitário federal da cidade do Rio de Janeiro. A população escolhida foi composta de trabalhadores da equipe de enfermagem, lotados no mínimo há seis meses neste serviço e que aceitassem participar da pesquisa. O questionário de coleta de dados utilizado foi adaptado por Mauro dos Guias e Avaliação de riscos em indústrias de Boix e Vogel. O estudo foi submetido e aprovado pelo Comitê de Ética em Pesquisa (CEP) do Hospital Universitário em estudo, através Parecer Consubstanciado no. 287/10, protocolo no. 217/09. Os dados foram analisados através do Programa Statistical Package for the Social Sciences (SPSS), versão 13.0. Os riscos biológicos foram os mais apontados pelos trabalhadores de enfermagem, seguidos dos riscos químicos, ergonômicos e de acidentes ou mecânicos. As doenças provocadas pelo trabalho mais referidas foram o estresse, a lombalgia, as varizes, a fadiga muscular e os problemas de articulação. As doenças agravadas pelo trabalho mais citadas foram as varizes, a lombalgia, os problemas de articulação, o estresse, as lesões de coluna vertebral, os problemas digestivos e os transtornos do sono. Conclui-se que o Serviço estudado possui riscos inerentes às atividades desenvolvidas que caracterizam os problemas relacionados pelos trabalhadores, e que são passíveis de controle através da intensificação de um Programa de Prevenção de Riscos Ambientais voltado para o Centro Cirúrgico. A partir da NR 17 e a 32, pode-se consultar as diretrizes para prevenção dos riscos encontrados. Uma estratégia de reposição digna de pessoal de enfermagem é imprescindível, assim como estudo e implantação de um Programa de Prevenção de Riscos laborais aos trabalhadores do Centro Cirúrgico, e utilização do questionário aos demais membros da equipe multiprofissional.

Avaliação tridimensional da via aérea superior de pacientes com apneia obstrutiva do sono que utilizaram aparelho de avanço mandibular

Os objetivos deste estudo foram avaliar o efeito do aparelho de avanço mandibular (Twin block - TB) no volume das vias aéreas superiores, por meio de tomografia computadorizada cone beam (CBCT); analisar, por meio da polissonografia, as mudanças no índice de apneia e hipopneia (IAH) e índice de apneia por hora de sono (IA), saturação de oxi-hemoglobina e eficiência do sono; e correlacionar o volume na CBCT e as polissonografias. Dezesseis pacientes portadores de apneia obstrutiva do sono, idade média de 47,06 anos, participaram deste estudo prospectivo, com acompanhamento médio de 7 meses. Foram feitas polissonografias iniciais (T1) e de acompanhamento (T2) com o TB em posição, e CBCT sem e com TB em posição. A segmentação e obtenção dos volumes das vias aéreas superiores foram realizadas e utilizados os testes t de Student pareado, de Wilcoxon e o índice de correlação de Spearman, com 5% de significância. Os resultados das polissonografias mostraram diferenças estatisticamente significativas entre T1 e T2 apenas para IAH (p<0,05). Houve aumento do volume da via aérea superior com TB quando comparado com o volume sem TB (p<0,05). Foi possível estabelecer-se correlação positiva entre volume da via aérea superior sem TB e IAH e IA em T1 (p<0,05), mas não houve correlação entre o volume da via aérea com TB e índices polissonográficos em T2. Pode-se concluir que, houve aumento de volume da via aérea superior com o TB e houve redução do IAH em T2 porém, sem correlação entre estes dados.

Riscos ocupacionais e problemas de saúde associados às condições de trabalho de enfermagem em unidades intensivas hospitalares

Trata-se de um estudo quantitativo, descritivo, visando uma análise das condições de trabalho em unidades intensivas de um hospital universitário no município do Rio de Janeiro. Foi definido como objeto de estudo a percepção dos trabalhadores de enfermagem sobre os riscos ocupacionais e os problemas de saúde inerentes às condições de trabalho em unidades intensivas e como problema de pesquisa: quais os riscos ocupacionais e problemas de saúde relacionados às condições de trabalho, percebidos pelos trabalhadores de enfermagem, em unidades intensivas de um hospital universitário? O objetivo geral foi estudar nas unidades intensivas os riscos ocupacionais e problemas de saúde da equipe de enfermagem e sua relação com condições de trabalho, a partir da percepção dos mesmos. Os objetivos específicos traçados foram: identificar as características pessoais e profissionais dos trabalhadores de enfermagem de unidades intensivas; descrever os fatores de risco do ambiente de trabalho percebidos pelos trabalhadores de enfermagem; levantar os problemas de saúde percebidos pelos trabalhadores e sua relação com o trabalho; analisar a associação entre os problemas de saúde percebidos pelos trabalhadores de enfermagem e as condições do trabalho em unidades intensivas. Participaram da pesquisa 125 profissionais de enfermagem de quatro unidades intensivas do Hospital Universitário (HU) entre Maio e Julho de 2009. A predominância foi de profissionais do sexo feminino, com idade acima dos 40 anos, com mais de um vínculo empregatício e trabalhando no HU há mais de 10 anos. Os riscos ocupacionais mais percebidos pelos trabalhadores foram os ergonômicos, seguido dos biológicos, de acidentes, físicos e químicos. Os problemas de saúde mais frequentes foram varizes, problemas oculares, lombalgias, estresse e depressão, transtornos do sono, lesões de coluna vertebral, dores de cabeça, mudanças no humor, dores musculares crônicas e hipertensão arterial. Pela associação entre riscos ocupacionais e problemas de saúde, conclui-se que os trabalhadores expostos a fatores de riscos ergonômicos e físicos têm maior probabilidade de adquirir problemas de saúde osteoarticulares e circulatórios (varizes). Diante dos dados desta pesquisa faz-se necessário aprofundamento da investigação sobre os fatores de riscos encontrados e possíveis medidas para minimizá-los, mediante novos estudos. Como recomendações destacam-se a criação de um espaço de discussão entre os gerentes e trabalhadores para a elaboração de um programa que vise a promoção e proteção da saúde do trabalhador de enfermagem de unidades intensivas; implementação de medidas de controle específicas para cada tipo de risco evidenciado e a criação de um Comitê de Ergonomia para operacionalizar a implementação das melhorias no HU, a fim de consolidar as transformações esperadas.