Global Models of Intermediate Timescale Variability on the Sun

In recent years a number of advances in both observation and theory have increased our understanding of the solar interior and how to model it. For climate studies, the timescale of interest for changes in the Sun ranges from decades to centuries. Some of the theoretical advances that will contribute to the building of global models of the Sun's variability on intermediate timescales are described. The current constraints on the important components are discussed. Finally a short discussion presenting some implications for input to climate modeling is presented

Very Early Optical Afterglows of Gamma-Ray Bursts: Evidence for Relative Paucity of Detection

Very early observations with the Swift satellite of γ-ray burst (GRB) afterglows reveal that the optical component is not detected in a large number of cases. This is in contrast to the bright optical flashes previously discovered in some GRBs (e.g., GRB 990123 and GRB 021211). Comparisons of the X-ray afterglow flux to the optical afterglow flux and prompt γ-ray fluence is used to quantify the seemingly deficient optical, and in some cases X-ray, light at these early epochs. This comparison reveals that some of these bursts appear to have higher than normal γ-ray efficiencies. We discuss possible mechanisms and their feasibility for explaining the apparent lack of early optical emission. The mechanisms considered include, foreground extinction, circumburst absorption, Lyα blanketing and absorption due to high-redshift, low-density environments, rapid temporal decay, and intrinsic weakness of the reverse shock. Of these, foreground extinction, circumburst absorption, and high redshift provide the best explanations for most of the nondetections in our sample. There is tentative evidence of suppression of the strong reverse shock emission. This could be because of a Poynting flux-dominated flow or a pure nonrelativistic hydrodynamic reverse shock

Solid State Proton Spin Relaxation and \u3ci\u3et\u3c/i\u3e-Butyl and Methyl Group Reorientation in 1-Bromo-2,4,6-Tri-\u3ci\u3et\u3c/i\u3e-Butylbenzene

We have used the solid state proton spin relaxation technique to investigate the barriers for methyl and t-butyl group reorientation in polycrystalline 1-bromo-2,4,6-tri-t-butylbenzene. The barriers in the range of 15-19 kJ/mol (3-5 kcal/mol) are compared with those found in related molecules. It is shown that the neighboring ring bromine atom has an effect on the barrier for t-butyl group reorientation similar to that of a neighboring hydrogen atom despite the significantly larger van der Waals\u27 radius of a bromine atom. This most likely occurs because of the relatively long carbon-bromine bond, the distorted ring geometry, and the relatively high polarizability of bromine. In addition, the barriers for methyl group reorientation, about 16 kJ/mol, seem to be largely intra-t-butyl in origin

Solid State Proton Spin Relaxation and \u3ci\u3et\u3c/i\u3e-Butyl and Methyl Group Reorientation in 1-Bromo-2,4,6-Tri-\u3ci\u3et\u3c/i\u3e-Butylbenzene

We have used the solid state proton spin relaxation technique to investigate the barriers for methyl and t-butyl group reorientation in polycrystalline 1-bromo-2,4,6-tri-t-butylbenzene. The barriers in the range of 15-19 kJ/mol (3-5 kcal/mol) are compared with those found in related molecules. It is shown that the neighboring ring bromine atom has an effect on the barrier for t-butyl group reorientation similar to that of a neighboring hydrogen atom despite the significantly larger van der Waals\u27 radius of a bromine atom. This most likely occurs because of the relatively long carbon-bromine bond, the distorted ring geometry, and the relatively high polarizability of bromine. In addition, the barriers for methyl group reorientation, about 16 kJ/mol, seem to be largely intra-t-butyl in origin

A cost-effective fluorescence detection system for pulsed laser analysis

A cost-effective fluorescence detection system has been developed using a National Instruments PCI-6251 data acquisition (DAQ) board that is driven by LabVIEW Signal Express. The signal is collected using a collimator and transported to the DAQ board using a fiber-coupled detector. The same detection system has been incorporated into an inverted microscope fitted with internal dichroic mirrors to provide a cost-effective alternative to commercial fluorescence microscopes. The detection system has been used to measure fluorescence intensity and generate a laser power curve that can be used for pulsed lasers. Different data analysis approaches have been compared and standard deviation and signal-to-noise ratios have been determined

ELMO1 has an essential role in the internalization of Salmonella Typhimurium into enteric macrophages that impacts disease outcome.

Backgrounds and aims4-6 million people die of enteric infections each year. After invading intestinal epithelial cells, enteric bacteria encounter phagocytes. However, little is known about how phagocytes internalize the bacteria to generate host responses. Previously, we have shown that BAI1 (Brain Angiogenesis Inhibitor 1) binds and internalizes Gram-negative bacteria through an ELMO1 (Engulfment and cell Motility protein 1)/Rac1-dependent mechanism. Here we delineate the role of ELMO1 in host inflammatory responses following enteric infection.MethodsELMO1-depleted murine macrophage cell lines, intestinal macrophages and ELMO1 deficient mice (total or myeloid-cell specific) was infected with Salmonella enterica serovar Typhimurium. The bacterial load, inflammatory cytokines and histopathology was evaluated in the ileum, cecum and spleen. The ELMO1 dependent host cytokines were detected by a cytokine array. ELMO1 mediated Rac1 activity was measured by pulldown assay.ResultsThe cytokine array showed reduced release of pro-inflammatory cytokines, including TNF-α and MCP-1, by ELMO1-depleted macrophages. Inhibition of ELMO1 expression in macrophages decreased Rac1 activation (~6 fold) and reduced internalization of Salmonella. ELMO1-dependent internalization was indispensable for TNF-α and MCP-1. Simultaneous inhibition of ELMO1 and Rac function virtually abrogated TNF-α responses to infection. Further, activation of NF-κB, ERK1/2 and p38 MAP kinases were impaired in ELMO1-depleted cells. Strikingly, bacterial internalization by intestinal macrophages was completely dependent on ELMO1. Salmonella infection of ELMO1-deficient mice resulted in a 90% reduction in bacterial burden and attenuated inflammatory responses in the ileum, spleen and cecum.ConclusionThese findings suggest a novel role for ELMO1 in facilitating intracellular bacterial sensing and the induction of inflammatory responses following infection with Salmonella

Timing of Intervention Affects Brain Electrical Activity in Children Exposed to Severe Psychosocial Neglect

Background: Early psychosocial deprivation has profound effects on brain activity in the young child. Previous reports have shown increased power in slow frequencies of the electroencephalogram (EEG), primarily in the theta band, and decreased power in higher alpha and beta band frequencies in infants and children who have experienced institutional care. Methodology/Principal Findings: We assessed the consequences of removing infants from institutions and placing them into a foster care intervention on brain electrical activity when children were 8 years of age. We found the intervention was successful for increasing high frequency EEG alpha power, with effects being most pronounced for children placed into foster care before 24 months of age. Conclusions/Significance: The dependence on age of placement for the effects observed on high frequency EEG alpha power suggests a sensitive period after which brain activity in the face of severe psychosocial deprivation is less amenable to recover

The Interaction of Photoactivators with Proteins during Microfabrication

Micron-scale protein cross-linking or microfabrication has been carried out using an Nd3+–YAG laser as the excitation source. Fabrication is carried out by the excitation of photoactivators (Rose Bengal, methylene blue and 9-fluorenone-2-carboxylic acid) with the ultimate goal of creating stable structures that will serve as models for various applications (drug delivery and tissue engineering). Experimental parameters have been adjusted to minimize photodamage and maximize cross-linking efficiency. The higher than ideal photon flux and peak power necessitates the use of high protein concentrations to minimize photodamage. Rose Bengal and methylene blue are binding to proteins with high association constants (Ka ≈ 106 M−1) and both Rose Bengal and both 9-fluorenone-2-carboxylic acid are showing changes to their excited states in presence of proteins at cross-linking concentrations. Molecular docking studies show that Rose Bengal binds close to the tryptophan with ΔG = −6.15 kcal/mol

ALE Meta-Analysis Workflows Via the Brainmap Database: Progress Towards A Probabilistic Functional Brain Atlas

With the ever-increasing number of studies in human functional brain mapping, an abundance of data has been generated that is ready to be synthesized and modeled on a large scale. The BrainMap database archives peak coordinates from published neuroimaging studies, along with the corresponding metadata that summarize the experimental design. BrainMap was designed to facilitate quantitative meta-analysis of neuroimaging results reported in the literature and supports the use of the activation likelihood estimation (ALE) method. In this paper, we present a discussion of the potential analyses that are possible using the BrainMap database and coordinate-based ALE meta-analyses, along with some examples of how these tools can be applied to create a probabilistic atlas and ontological system of describing function–structure correspondences