Fcc-bcc transition for Yukawa interactions determined by applied strain deformation

Calculations of the work required to transform between bcc and fcc phases yield a high-precision bcc-fcc transition line for monodisperse point Yukawa (screened-Couloumb) systems. Our results agree qualitatively but not quantitatively with previously published simulations and phenomenological criteria for the bcc-fcc transition. In particular, the bcc-fcc-fluid triple point lies at a higher inverse screening length than previously reported.Comment: RevTex4, 9 pages, 6 figures. Discussion of phase coexistence extended, a few other minor clarifications added, referencing improved. Accepted for publication by Physical Review

Rickettsia mongolotimonae: a rare pathogen in France.

We report a second case of laboratory-confirmed infection caused by Rickettsia mongolotimonae in Marseille, France. This rickettsiosis may represent a new clinical entity; moreover, its geographic distribution may be broader than previously documented. This pathogen should be systematically considered in the differential diagnosis of atypical rickettsioses, especially rashless fevers with lymphangitis and lymphadenopathy, in southern France and perhaps elsewhere

The Role of CT-Based Attenuation Correction and Collimator Blurring Correction in Striatal Spect Quantification

Purpose. Striatal single photon emission computed tomography (SPECT) imaging of the dopaminergic system is becoming increasingly used for clinical and research studies. The question about the value of nonuniform attenuation correction has become more relevant with the increasing availability of hybrid SPECT-CT scanners. In this study, the value of nonuniform attenuation correction and correction for collimator blurring were determined using both phantom data and patient data. Methods. SPECT imaging was performed using 7 anthropomorphic phantom measurements, and 14 patient studies using [I-123]-FP-CIT (DATSCAN). SPECT reconstruction was performed using uniform and nonuniform attenuation correction and collimator blurring corrections. Recovery values (phantom data) or average-specific uptake ratios (patient data) for the different reconstructions were compared at similar noise levels. Results. For the phantom data, improved recovery was found with nonuniform attenuation correction and collimator blurring corrections, with further improvement when performed together. However, for patient data the highest average specific uptake ratio was obtained using collimator blurring correction without nonuniform attenuation correction, probably due to subtle SPECT-CT misregistration. Conclusions. This study suggests that an optimal brain SPECT reconstruction (in terms of the lowest bias) in patients would include a correction for collimator blurring and uniform attenuation correction

First experimental results of very high accuracy centroiding measurements for the neat astrometric mission

NEAT is an astrometric mission proposed to ESA with the objectives of detecting Earth-like exoplanets in the habitable zone of nearby solar-type stars. NEAT requires the capability to measure stellar centroids at the precision of 5e-6 pixel. Current state-of-the-art methods for centroid estimation have reached a precision of about 2e-5 pixel at two times Nyquist sampling, this was shown at the JPL by the VESTA experiment. A metrology system was used to calibrate intra and inter pixel quantum efficiency variations in order to correct pixelation errors. The European part of the NEAT consortium is building a testbed in vacuum in order to achieve 5e-6 pixel precision for the centroid estimation. The goal is to provide a proof of concept for the precision requirement of the NEAT spacecraft. In this paper we present the metrology and the pseudo stellar sources sub-systems, we present a performance model and an error budget of the experiment and we report the present status of the demonstration. Finally we also present our first results: the experiment had its first light in July 2013 and a first set of data was taken in air. The analysis of this first set of data showed that we can already measure the pixel positions with an accuracy of about 1e-4 pixel.Comment: SPIE conference proceeding

Coherent Control of Photocurrents in Graphene and Carbon Nanotubes

Coherent one photon ($2 \omega$) and two photon ($\omega$) electronic excitations are studied for graphene sheets and for carbon nanotubes using a long wavelength theory for the low energy electronic states. For graphene sheets we find that coherent superposition of these excitations produces a polar asymmetry in the momentum space distribution of the excited carriers with an angular dependence which depends on the relative polarization and phases of the incident fields. For semiconducting nanotubes we find a similar effect which depends on the square of the semiconducting gap, and we calculate its frequency dependence. We find that the third order nonlinearity which controls the direction of the photocurrent is robust for semiconducting t ubes and vanishes in the continuum theory for conducting tubes. We calculate corrections to these results arising from higher order crystal field effects on the band structure and briefly discuss some applications of the theory.Comment: 12 pages in RevTex, 6 epsf figure

TCR V α- and V ß-Gene Segment Use in T-Cell Subcultures Derived from a Type-III Bare Lymphocyte Syndrome Patient Deficient in MHC Class-II Expression

Previously, we and others have shown that MHC class-II deficient humans have greatly reduced numbers of CD4+CD8– peripheral T cells. These type-III Bare Lymphocyte Syndrome patients lack MHC class-II and have an impaired MHC class-I antigen expression. In this study, we analyzed the impact of the MHC class-II deficient environment on the TCR V-gene segment usage in this reduced CD4+CD8– T-cell subset. For these studies, we employed TcR V-region-specific monoclonal antibodies (mAbs) and a semiquantitative PCR technique with V α and V ß amplimers, specific for each of the most known V α- and V ß;-gene region families. The results of our studies demonstrate that some of the V α-gene segments are used less frequent in the CD4+CD8– T-cell subset of the patient, whereas the majority of the TCR V α- and V ß-gene segments investigated were used with similar frequencies in both subsets in the type-III Bare Lymphocyte Syndrome patient compared to healthy control family members. Interestingly, the frequency of TcR V α12 transcripts was greatly diminished in the patient, both in the CD4+CD8– as well as in the CD4–CD8+ compartment, whereas this gene segment could easily be detected in the healthy family controls. On the basis of the results obtained in this study, it is concluded that within the reduced CD4+CD8– T-cell subset of this patient, most of the TCR V-gene segments tested for are employed. However, a skewing in the usage frequency of some of the V α-gene segments toward the CD4–CD8+ T-cell subset was noticeable in the MHC class-II deficient patient that differed from those observed in the healthy family controls

Efficacy of power training to improve physical function in individuals diagnosed with frailty and chronic disease: A meta-analysis

Muscle power training with emphasis on high-velocity of concentric movement improves physical functionality in healthy older adults, and, maybe superior to traditional exercise programs. Power training may also be advantageous for patients with acute and chronic illnesses, as well as frail individuals. To determine the efficacy of power training compared with traditional resistance training on physical function outcomes in individuals diagnosed with frailty, acute illness or chronic disease. PubMed (MEDLINE), CINAHL, PEDro, Web of Science, and Google Scholar. (1) at least one study group receives muscle power training of randomized controlled trial (RCT) (2) study participants diagnosed as prefrail, frail or have an ongoing acute or chronic disease, condition or illness; (3) study participants over the age of 18; (4) publication in English language; (5) included physical function as the primary or secondary outcome measures. Two independent reviewers assessed articles for inclusion and graded the methodological quality using Cochrane Risk-of- Bias tool for RCTs. Fourteen RCTs met the inclusion criteria. In seven studies, muscle power training was more effective at improving physical function compared to control activities with a mean fixed effect size (ES) of 0.41 (p = 0.006; 95% CI 0.12 to 0.71). Power training and conventional resistance training had similar effectiveness in eight studies with a mean fixed ES of 0.10 (p = 0.061; 95% CI –0.01 to 0.40). Muscle power training is just as efficacious for improving physical function in individuals diagnosed with frailty and chronic disease when compared to traditional resistance training. The advantages of power training with reduced work per session may support power training as a preferential exercise modality for clinical populations. The findings should be interpreted with caution since generalizability is questioned due to the heterogeneity of patient populations enrolled and participants were relatively mobile at baseline