A test-retest fMRI dataset for motor, language and spatial attention functions

Background Since its inception over twenty years ago, functional magnetic resonance imaging (fMRI) has been used in numerous studies probing neural underpinnings of human cognition. However, the between session variance of many tasks used in fMRI remains understudied. Such information is especially important in context of clinical applications. A test-retest dataset was acquired to validate fMRI tasks used in pre-surgical planning. In particular, five task-related fMRI time series (finger, foot and lip movement, overt verb generation, covert verb generation, overt word repetition, and landmark tasks) were used to investigate which protocols gave reliable single-subject results. Ten healthy participants in their fifties were scanned twice using an identical protocol 2–3 days apart. In addition to the fMRI sessions, high-angular resolution diffusion tensor MRI (DTI), and high-resolution 3D T1-weighted volume scans were acquired. Findings Reliability analyses of fMRI data showed that the motor and language tasks were reliable at the subject level while the landmark task was not, despite all paradigms showing expected activations at the group level. In addition, differences in reliability were found to be mostly related to the tasks themselves while task-by-motion interaction was the major confounding factor. Conclusions Together, this dataset provides a unique opportunity to investigate the reliability of different fMRI tasks, as well as methods and algorithms used to analyze, de-noise and combine fMRI, DTI and structural T1-weighted volume data

Sub-luminous type Ia supernovae from the mergers of equal-mass white dwarfs with M~0.9 M_sun

Type Ia supernovae (SNe Ia) are thought to result from thermonuclear explosions of carbon-oxygen white dwarf stars. Existing models generally explain the observed properties, with the exception of the sub-luminous 1991-bg-like supernovae. It has long been suspected that the merger of two white dwarfs could give rise to a type Ia event, but hitherto simulations have failed to produce an explosion. Here we report a simulation of the merger of two equal-mass white dwarfs that leads to an underluminous explosion, though at the expense of requiring a single common-envelope phase, and component masses of ~0.9 M_sun. The light curve is too broad, but the synthesized spectra, red colour and low expansion velocities are all close to what is observed for sub-luminous 1991bg-like events. While mass ratios can be slightly less than one and still produce an underluminous event, the masses have to be in the range 0.83-0.9 M_sun.Comment: Accepted to Natur

Measurements of the Correlation Function of a Microwave Frequency Single Photon Source

At optical frequencies the radiation produced by a source, such as a laser, a black body or a single photon source, is frequently characterized by analyzing the temporal correlations of emitted photons using single photon counters. At microwave frequencies, however, there are no efficient single photon counters yet. Instead, well developed linear amplifiers allow for efficient measurement of the amplitude of an electromagnetic field. Here, we demonstrate how the properties of a microwave single photon source can be characterized using correlation measurements of the emitted radiation with such detectors. We also demonstrate the cooling of a thermal field stored in a cavity, an effect which we detect using a cross-correlation measurement of the radiation emitted at the two ends of the cavity.Comment: 5 pages, 4 figure

Impacts of implementing a reference center in special nutritional formulae

Introdução: Em 2005, no Estado do Rio Grande do Sul, foi criado o Centro de Referência para Assessoria em Fórmulas Nutricionais Especiais (CR), com a finalidade de avaliar tecnicamente as solicitações de fórmulas nutricionais especiais (FNE), pelos usuários do SUS, à Secretaria Estadual de Saúde. O objetivo deste estudo é comparar características de solicitações e usuários e estimar custos em dois períodos pós-implantação do CR no Estado do RS. Métodos: A unidade de pesquisa foi cada solicitação de FNE. Os grupos de comparação foram constituídos por todas as solicitações avaliadas no primeiro (período 1 / n = 1077) e terceiro (período 2 / n = 944) anos de funcionamento do CR. Resultados: Houve aumento da proporção de solicitações judiciais (p<0,001), melhora do preenchimento das requisições (p<0,001) e do percentual de aprovações aos pedidos de FNE (p<0,001), para mais usuários (p=0,004). Aumentaram as solicitações para desnutridos (p=0,002) e idosos (p<0,001) e reduziram as duplicidades de solicitações no período (p<0,001). O custo estimado por usuário diminuiu de US$8,742 para US$ 6,297. Conclusões: A implantação do CR contribuiu para aprimorar o processo de solicitação e análise de pedidos de FNE, repercutindo em mais avaliações favoráveis ao fornecimento de fórmulas, para mais usuários, a menores custos.Introduction: In 2005, the Center of Reference (CR) for Consultancy in Nutritional Special Formulas was created in the State of Rio Grande do Sul in order to technically evaluate the requests for special nutritional formulas (SNF) made by SUS users to the State Department of Health. The aim of this study is to compare the characteristics of applications and users and to estimate costs in both periods after implementation of the CR in the state of RS. Methods: The research unit was each requested SNF. The comparison groups were composed of all requests evaluated in the first (period 1 / n = 1077) and third (period 2 / n = 944) years of the CR. Results: Increased proportion of court orders (p<0.001), improvement of the fulfillment of orders (p<0.001) and of the percentage of approvals of applications for SNF (p<0.001) for more users (p=0.004). There were increased requests for malnourished (p = 0.002) and elderly (p<0.001) and decreased duplications of requests in the period (p<0.001). The estimated cost per user declined from US$8,742 to US$ 6,297. Conclusions: The implementation of this CR has helped to improve the process to request and review applications for SNF, reflecting more favorable ratings in the supply of formulas, to more users and at lower costs

Bench-to-bedside review : targeting antioxidants to mitochondria in sepsis

Peer reviewedPublisher PD

HERV-W/MRSV envelope transcripts detection\ud in blood of multiple sclerosis patients after\ud Natalizumab treatment

FAPESP 2010/10619-

At the crossroads of biomacromolecular research: highlighting the interdisciplinary nature of the field

Due to their complexity and wide-ranging utility, biomacromolecular research is an especially interdisciplinary branch of chemistry. It is my goal that the Biomacromolecules subject area of Chemistry Central Journal will parallel this richness and diversity. In this inaugural commentary, I attempt to set the stage for achieving this by highlighting several areas where biomacromolecular research overlaps more traditional chemistry sub-disciplines. Specifically, it is discussed how Materials Science and Biotechnology, Analytical Chemistry, Cell Biology and Chemical Theory are each integral to modern biomacromolecular research. Investigators with reports in any of these areas, or any other dealing with biomacromolecules, are encouraged to submit their research papers to Chemistry Central Journal

Disentangling astroglial physiology with a realistic cell model in silico

Electrically non-excitable astroglia take up neurotransmitters, buffer extracellular K+ and generate Ca2+ signals that release molecular regulators of neural circuitry. The underlying machinery remains enigmatic, mainly because the sponge-like astrocyte morphology has been difficult to access experimentally or explore theoretically. Here, we systematically incorporate multi-scale, tri-dimensional astroglial architecture into a realistic multi-compartmental cell model, which we constrain by empirical tests and integrate into the NEURON computational biophysical environment. This approach is implemented as a flexible astrocyte-model builder ASTRO. As a proof-of-concept, we explore an in silico astrocyte to evaluate basic cell physiology features inaccessible experimentally. Our simulations suggest that currents generated by glutamate transporters or K+ channels have negligible distant effects on membrane voltage and that individual astrocytes can successfully handle extracellular K+ hotspots. We show how intracellular Ca2+ buffers affect Ca2+ waves and why the classical Ca2+ sparks-and-puffs mechanism is theoretically compatible with common readouts of astroglial Ca2+ imaging