The VLT-FLAMES survey of massive stars: atmospheric parameters and rotational velocity distributions for B-type stars in the Magellanic Clouds (vol 457, pg 265, 2006)

We correct the estimates of the dispersions in the rotational velocities for early-type stars in our Galaxy (Dufton et al. 2006, A&A, 457, 265) and the Magellanic Clouds (Hunter et al. 2008, A&A, 479, 541). The corrected values are pi(1/4) (i.e. approximately 33%) larger than those published in the original papers.

RS-0406 arrests amyloid-B oligomer-induced behavioural deterioration in vivo

Clinically accessible compounds that arrest or reverse the effects of amyloid-ß (Aß) on progressively developing behavioural symptomatology and neuropathology in Alzheimer's disease (AD) have yet to become available. However, a viable strategy may be to target and neutralise soluble Aß oligomers, which have been shown to mediate synaptic dysfunction and to produce cognitive deficits in the intact organism. Inhibiting the aggregation of Aß is therapeutically attractive, as Aß aggregation is a pathological event and pharmacological interventions targeting this are likely to have a non-toxic profile. A behavioural assay, the alternating-lever cyclic-ratio schedule, was used to assess the effect of Aß oligomers and the non-peptide small molecule RS-0406 in male Sprague-Dawley rats. RS-0406 has been shown to inhibit Aß1-42 fibrillogenesis and protect against Aß1-42–induced cytotoxicity in primary hippocampal neurons. In the current study, RS-0406 ameliorated the adverse effects of secreted oligomers of human Aß on behaviour and dose dependently reduced the behavioural effects of Aß oligomers, with the highest dose, 10 µM, maintaining behaviour approximately at control levels. This effect appeared to be central; peripheral confounds having been extensively investigated. This is the first published report on the effects of RS-0406 in vivo and indicates that RS-0406 has potential as a pharmacotherapeutic intervention for behavioural deficits seen in the early stages of AD, and possibly as an intervention in the development of AD neuropathology. Indeed, an analogue of RS-0406 that could be administered peripherally might be a realistic candidate for the clinical treatment of AD.

The mid-infrared dielectric function of NBCO in the a-b plane from 85 K to 300 K

Results are reported on the a-b plane dielectric function (epsilon) of thin-film c-axis NdBa2Cu3O7-delta with close to optimal oxygen doping (T-c similar to 90 K) in the mid-infrared (wavelength 3.392 mum) over the temperature range 85 K to 300 K. An attenuated total reflectance technique based on the excitation of surface plasmon polaritons is used. The results show that \epsilon (r)\ decreases quasi-linearly with increasing temperature, while Ei is invariant with temperature to within experimental uncertainties. Representative values are epsilon = [epsilon (r) + i epsilon (i)] = (-12.9 +/- 0.6) + i(23.0 +/- 1.5) at T similar to 295 K and epsilon = (-15.7 +/- 0.7) + i(23.5 +/- 1.1) at T similar to 90 K. The raw data an interpreted in terms of the generalized Drude model which gives effective scattering rates (1/tau*) that increase with temperature from about 3800 cm(-1) at 90 K to about 4300 cm(-1) at 295 K. There are indications of a superlinear T-dependence in the scattering, 1/tau*: a fit to a function of the form 1/tau* = A + BTalpha gives alpha = 2.8 +/- 0.7. The effective plasma frequency, omega (p)*, with an average value of approximately 21 000 cm(-1) was independent of temperature.

Development and validation of rapid disequilibrium enzyme-linked immunosorbent assays for the detection of Methyl Yellow and Rhodamine B dyes in foods

Sensitive and specific enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of two illegal synthetic dyes: Methyl Yellow (MY) and Rhodamine B (RB) in food. Polyclonal antibodies were raised against synthesised immunogens and employed in unique direct disequilibrium ELISAs. The time of the assays was only twenty minutes (five minutes for each incubation step with sample and enzyme conjugate and ten minutes with enzyme substrate). The IC50 for MY was in the range 1.4-4.2 ng mL(-1) and for RB 0.1-0.5 ng mL(-1). A simple sample preparation method was developed for the analysis of a range of sauces. In the case of spices a dispersive solid phase extraction was applied to purify the extracts. The testing of twenty samples took approximately one and a half hours (including sample preparation and analysis). Both assays were validated according to the Commission Decision 2002/657/EC criteria for use in sauces and spices. The detection capability for MY in sauces and spices was determined to be less than 15 ng g(-1) and 50 ng g(-1), respectively and for RB, 10 ng g(-1) for both types of food samples. The precision of the developed assays was determined in a repeatability study. The intra-and inter-assay coefficients of variation were less than 25% for both tests and matrix types. The simplicity and performance of both assays indicate that they will be very reliable screening methods for the detection of the illegal dyes MY and RB in a range of food products.

Human B cell colony growth from pre-B cells in vitro

We describe a simple one-step technique for the growth of human B cell colonies in semi-solid agar in vitro. This method used conditioned medium from the human plasmacytoma cell line LICR-LON-H My 2 as a source of stimulating activity. A linear relationship exists between the number of B cells seeded and the number of colonies formed (r = 0.95). Most colony forming cells, approximately 1 in 500 of B cells seeded, lack surface immunoglobulin, possess Fc receptors and mark with the Leu 12 monoclonal antibody. Cells within developing colonies are found to have cytoplasmic IgM, IgA and IgG depending on the length of time in culture.

Effect of ultraviolet-B light on lymphocyte activity at doses at which normal bone marrow stem cells are preserved

Ultraviolet B (UVB) light is known to be immunosuppressive, but, probably because of a small UVC component in the emission spectra of some of the UVB lamps used, reports vary on effective dose levels. To prevent potentially lethal graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation, alloreactive donor T-cell activity must be suppressed. In this study, a narrow wavelength UVB lamp (TL01, 312 nm peak emission) was used to determine what doses of UVB were required to abolish rat lymphocyte proliferation while simultaneously preserving rat bone marrow progenitor cell and primitive hematopoietic stem cell viability. Lymphocyte proliferation, as measured by 3H-Thymidine incorporation, in response to lectin stimulation was abolished below detection at doses greater than 3,500 J/m2. When T-cell clonogenicity was measured in a limiting dilution assay, a small fraction (0.6%) was maintained at doses up to 4,000 J/m2. Cytotoxic T-lymphocyte (CTL) activity was reduced after treatment with 4,000 J/m2, but a significant level of cytotoxicity was still maintained. Natural killer cell cytolytic activity was not affected by doses up to 4,000 J/m2. At 4,000 J+m2 there was a 10% survival of colony-forming units-granulocyte-macrophage; a 1% and 4% survival of day-8 and day-12 colony-forming units-spleen, respectively; and 11% survival of marrow repopulating ability cells. Up to 25% of late cobblestone area forming cells (4 to 5 weeks), reflecting the more immature hematopoietic stem cells, were preserved in bone marrow treated with 4,000 J/m2, indicating that early stem cells are less sensitive to UVB damage than are more committed progenitor cells. Thus, a potential therapeutic window was established at approximately 4,000 J/m2 using this light source, whereby the potentially GVHD-inducing T cells were suppressed, but a sufficient proportion of the cells responsible for engraftment was maintained.

Electron-impact ionization of B+

Electron-impact ionization cross sections are calculated for the ground and metastable states of B+. Com- parisons between perturbative distorted-wave and nonperturbative close-coupling calculations find reductions in the direct ionization cross sections due to long-range electron correlation effects of approximately 10% for the ground state and approximately 15% for the metastable state. Previous crossed-beams experiments, with a metastable to ground ratio of between 50% and 90%, are found to be in reasonable agreement with metastable state close-coupling results. New crossed-beams experiments, with a metastable to ground ratio of only 9%, are found to be in reasonable agreement with ground state close-coupling results. Combined with previous work on neutral B and B2+, the nonperturbative close-coupling calculations provide accurate ionization cross sections for the study of edge plasmas in controlled fusion research.

Crystallization in poly(L-lactide)-b-poly(epsilon-caprolactone) double crystalline diblock copolymers: a study using X-ray scattering, differential scanning calorimetry, and polarized optical microscopy

The crystallization of well-defined poly(L-lactide)-b-poly(epsilon-caprolactone) diblock copolymers, PLLA-b-PCL, was investigated by time-resolved X-ray techniques, polarized optical microscopy (POM), and differential scanning calorimetry (DSC). Two compositions were studied that contained 44 and 60 wt % poly(L-lactide), PLLA (they are referred to as (L44C5614)-C-11 and (L60C409)-C-12, respectively, with the molecular weight of each block in kg/mol as superscript). The copolymers were found to be initially miscible in the melt according to small-angle X-ray scattering measurements (SAXS). Their thermal behavior was also indicative of samples whose crystallization proceeds from a mixed melt. Sequential isothermal crystallization from the melt at 100 degreesC (for 30 min) and then at 30 degreesC (for 15 min) was measured. At 100 degreesC only the PLLA block is capable of crystallization, and its crystallization kinetics was followed by both WAXS and DSC; comparable results were obtained that indicated an instantaneous nucleation with three-dimensional superstructures (Avrami index of approximately 3). The spherulitic nature of the superstructure was confirmed by POM. When the temperature was decreased to 30 degreesC, the PCL block was able to crystallize within the PLLA negative spherulites (with an Avrami index of 2, as opposed to 3 in homo-PCL), and its crystallization rate was much slower than an equivalent homo-PCL. Time-resolved SAXS experiments in (L60C409)-C-12 revealed an initial melt mixed morphology at 165 degreesC that upon cooling transformed into a transient microphase-separated lamellar structure prior to crystallization at 100 degreesC.

Nonspherical assemblies generated from polystyrene-b-poly(L-lysine) polyelectrolyte block copolymers

This report describes the aqueous solution self-assembly of a series of polystyrene(m)-b-poly(L-lysine)n block copolymers (m = 8-10; n = 10-70). The polymers are prepared by ring-opening polymerization of epsilon-benzyloxycarbonyl-L-lysine N-carboxyanhydride using amine terminated polystyrene macroinitiators, followed by removal of the benzyloxycarbonyl side chain protecting groups. The critical micelle concentration of the block copolymers determined using the pyrene probe technique shows a parabolic dependence on peptide block length exhibiting a maximum at n = approximately 20 (m = 8) or n = approximately 60 (m = 10). The shape and size of the aggregates has been studied by dynamic and static light scattering, small-angle neutron scattering (SANS), and analytical ultracentrifugation (AUC). Surprisingly, Holtzer and Kratky analysis of the static light scattering results indicates the presence of nonspherical, presumably cylindrical objects independent of the poly(L-lysine)n block length. This is supported by SANS data, which can be fitted well by assuming cylindrical scattering objects. AUC analysis allows the molecular weight of the aggregates to be estimated as several million g/mol, corresponding to aggregation numbers of several 10s to 100s. These aggregation numbers agree with those that can be estimated from the length and diameter of the cylinders obtained from the scattering results.

Potential role of vegetation feedback in the climate sensitivity of high-latitude regions: a case study at 6000 years B.P.

Previous climate model simulations have shown that the configuration of the Earth's orbit during the early to mid-Holocene (approximately 10–5 kyr) can account for the generally warmer-than-present conditions experienced by the high latitudes of the northern hemisphere. New simulations for 6 kyr with two atmospheric/mixed-layer ocean models (Community Climate Model, version 1, CCMl, and Global ENvironmental and Ecological Simulation of Interactive Systems, version 2, GENESIS 2) are presented here and compared with results from two previous simulations with GENESIS 1 that were obtained with and without the albedo feedback due to climate-induced poleward expansion of the boreal forest. The climate model results are summarized in the form of potential vegetation maps obtained with the global BIOME model, which facilitates visual comparisons both among models and with pollen and plant macrofossil data recording shifts of the forest-tundra boundary. A preliminary synthesis shows that the forest limit was shifted 100–200 km north in most sectors. Both CCMl and GENESIS 2 produced a shift of this magnitude. GENESIS 1 however produced too small a shift, except when the boreal forest albedo feedback was included. The feedback in this case was estimated to have amplified forest expansion by approximately 50%. The forest limit changes also show meridional patterns (greatest expansion in central Siberia and little or none in Alaska and Labrador) which have yet to be reproduced by models. Further progress in understanding of the processes involved in the response of climate and vegetation to orbital forcing will require both the deployment of coupled atmosphere-biosphere-ocean models and the development of more comprehensive observational data sets

Motor perseveration during an A not B task in children with intellectual disabilities

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of B-d mixing using opposite-side flavor tagging

We report on a measurement of the B-d(0) mixing frequency and the calibration of an opposite-side flavor tagger in the D0 experiment. Various properties associated with the b quark on the opposite side of the reconstructed B meson are combined using a likelihood-ratio method into a single variable with enhanced tagging power. Its performance is tested with data, using a large sample of reconstructed semileptonic B ->mu(DX)-X-0 and B ->mu(DX)-X-* decays, corresponding to an integrated luminosity of approximately 1 fb(-1). The events are divided into groups depending on the value of the combined tagging variable, and an independent analysis is performed in each group. Combining the results of these analyses, the overall effective tagging power is found to be epsilon D-2=(2.48 +/- 0.21(-0.06)(+0.08))%. The measured B-d(0) mixing frequency Delta m(d)=0.506 +/- 0.020(stat)+/- 0.016(syst) ps(-1) is in good agreement with the world average value.

Measurement of the B-s(0) lifetime in the exclusive decay channel B-s(0)-> J/psi phi

Using the exclusive decay B-s(0)-->J/psi(mu(+)mu(-))phi(K+K-), we report the most precise single measurement of the B-s(0) lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb(-1) collected with the D0 detector at the Fermilab Tevatron Collider in 2002-2004. We reconstruct 337 signal candidates, from which we extract the B-s(0) lifetime, tau(B-s(0))=1.444(-0.090)(+0.098)(stat)+/-0.020(sys) ps. We also report a measurement for the lifetime of the B-0 meson using the exclusive decay B-0-->J/psi(mu(+)mu(-))K-*0(892)(K(+)pi(-)). We reconstruct 1370 signal candidates, obtaining tau(B-0)=1.473(-0.050)(+0.052)(stat)+/-0.023(sys) ps, and the ratio of lifetimes, tau(B-s(0))/tau(B-0)=0.980(-0.071)(+0.076)(stat)+/-0.003(sys).

Measurement of the B-s(0) lifetime using semileptonic decays

We report a measurement of the B-s(0) lifetime in the semileptonic decay channel B-s(0)-> D-s(-)mu(+)nu X (and its charge conjugate), using approximately 0.4 fb(-1) of data collected with the D0 detector during 2002-2004. Using 5176 reconstructed D-s(-)mu(+) signal events, we have measured the B-s(0) lifetime to be tau(B-s(0))=1.398 +/- 0.044(stat)(-0.025)(+0.028)(syst) ps. This is the most precise measurement of the B-s(0) lifetime to date.

Measurement of the Lambda(0)(b) lifetime in the decay Lambda(0)(b)-> J/psi Lambda(0) with the D0 detector

We present measurements of the Lambda(b)(0) lifetime in the exclusive decay channel Lambda(b)(0)-> J/psi Lambda(0), with J/psi ->mu(+)mu(-) and Lambda(0)-> p pi(-), the B-0 lifetime in the decay B-0-> J/psi K-S(0) with J/psi ->mu(+)mu(-) and K-S(0)->pi(+)pi(-), and the ratio of these lifetimes. The analysis is based on approximately 250 pb(-1) of data recorded with the D0 detector in p (p) over bar collisions at root s = 1.96 TeV. The Lambda(b)(0) lifetime is determined to be tau(Lambda(b)(0))=1.22(-0.18)(+0.22)(stat)+/- 0.04(syst) ps, the B-0 lifetime tau(B-0)=1.40(-) (+0.11)(0.10)(stat)+/- 0.03(syst) ps, and the ratio tau(Lambda(b)(0))/tau(B-0)=0.87(-) (+0.17)(0.14)(stat)+/- 0.03(syst). In contrast with previous measurements using semileptonic decays, this is the first determination of the Lambda(b)(0) lifetime based on a fully reconstructed decay channel.