New Paradigm in NKT Cell Antigens: MCS-0208 (2-(Hydroxymethyl)phenylthio-phytoceramide) – an Aryl-Phytoceramide Compound with a Single Hydroxyl Group Stimulates NKT Cells

Natural Killer T (NKT) cells play an important role in the immune response and can be activated by glycolipids presented by CD1d protein. We present MCS-0208, an unprecedented arylthioether-phytoceramide able to induce potent invariant NKT (iNKT) cell activation, notably when tested in human iNKT cells. This arylsphingolipid analog has a simple phenyl group containing a single hydroxyl substituent as a surrogate of the sugar ring. The phenylthioether structure contrasts with α-galactosylceramide ( 1 ), the prototypical glycolipid used to induce iNKT cell stimulation, where the galactose 2’-OH and 3’-OH substituents are accepted as the minimal footprint and considered critical for NKT T cell receptor (TCR) recognition. A computational study supports the recognition of aromatic compound by the CD1d and TCR proteins as radically new structures for NKT cell stimulation.     

MicroRNA Profiling of B Cell Subsets from Systemic Lupus Erythematosus Patients Reveals Promising Novel Biomarkers

MicroRNAs control the differentiation and function of B cells, which are considered key elements in the pathogenesis of systemic lupus erythematosus (SLE). However, a common micro(mi)RNA signature has not emerged since published data includes patients of variable ethnic background, type of disease, and organ involvement, as well as heterogeneous cell populations. Here, we aimed at identifying a miRNA signature of purified B cells from renal and non-renal severe SLE patients of Latin American background, a population known to express severe disease. Genome-wide miRNA expression analyses were performed on naive and memory B cells and revealed two categories of miRNA signatures. The first signature represents B cell subset-specific miRNAs deregulated in SLE: 11 and six miRNAs discriminating naive and memory B cells of SLE patients from healthy controls (HC), respectively. Whether the miRNA was up or down-regulated in memory B cells as compared with naive B cells in HC, this difference was abolished in SLE patients, and vice versa. The second signature identifies six miRNAs associated with specific pathologic features affecting renal outcome, providing a further understanding for SLE pathogenesis. Overall, the present work provided promising biomarkers in molecular diagnostics for disease severity as well as potential new targets for therapeutic intervention in SLE.     

Stimulation of Sertoli cell proliferation: defining the response interval to an inhibitor of estrogen synthesis in the boar

Sertoli cell proliferation occurs in two major waves after birth, one neonatally and another prepubertally, each contributing to final testicular size and sperm production. However, little is known about the regulation of either wave. We have previously shown that letrozole, an inhibitor of estrogen synthesis, increases Sertoli cell number and testicular size at sexual maturity in boars. These studies were conducted to determine whether letrozole affects the first or second proliferative wave. Boars were treated with letrozole during the first wave (treatment at 1, 3, and 5 weeks), less frequently (1 week of age only, or 1 and 5 weeks), on postnatal day 1, or during the second wave (weeks 11-16). Sertoli cells were enumerated in testes and estrogen concentrations were evaluated in serum and testes. Compared with vehicle controls, letrozole reduced estrogen in boars treated at weeks 1 and 5 or 1, 3, and 5, on postnatal day 1, or prepubertally. However, Sertoli cell numbers were increased only in boars treated at 1, 3, and 5 weeks of age. Neither perinatal (1 day old) nor prepubertal letrozole treatment affected Sertoli cell numbers. Hence, Sertoli cell proliferation was sensitive to letrozole only if letrozole was administered throughout the first wave, even though estrogen synthesis was effectively inhibited at all ages. These data indicate that the neonatal but not the prepubertal window of Sertoli cell proliferation is sensitive to an inhibitor of estrogen synthesis; this suggests that these two waves are differently regulated.     

New thermosets obtained by copolymerization of DGEBA with 1,5,7,11-tetraoxaspiro[5,5]undecane catalyzed by lanthanide triflates

DGEBA epoxy resin was cured with different proportions of 1,5,7,11-tetraoxaspiro[5,5]undecane (TOSU) with ytterbium and lanthanum triflates as catalysts. The curing was studied by differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated-total-reflexion mode (FTIR/ATR).FITR/ATR was used to monitor the competitive reactive processes and to quantify the evolution of the epoxide, orthocarbonate, linear carbonate and other groups formed in the curing process. The T_g of the cured materials decreased when the proportion of TOSU increased. The kinetics were studied by DSC experiments and analyzed with iso-conversional procedures. The systems catalyzed by ytterbium triflate had a higher curing rate and reached a higher degree of cross-linking. The addition of TOSU reduced the degree of overall shrinkage and even led to one material expanding. The flexibility and the degradability of these materials were improved by introducing higher proportions of TOSU.     

Influence of the elimination and addition of seeds on the colour,phenolic composition and astringency of red wine

Several winemaking techniques have been developed to eliminate seeds to prevent the release of high amounts of very astringent proanthocyanidins, especially when the grapes are unripe. However, there is no scientific information on the effects of this practice. The aim of this paper is to study how the elimination and addition of seeds influence the colour, phenolic composition and astringency of red wine. The elimination of around 80% of the seeds led to a significant decrease of colour intensity and anthocyanin concentration. The addition of seeds originated wines with a greater concentration of total anthocyanin, but did not significantly affect the wine colour. These wines also presented significantly higher levels of proanthocyanidins, a greater proportion of epicatechin-3-gallate, a lower mean degree of polymerization, and, in particular, a drastic increase in astringency. Wines obtained with the elimination of seeds, on the other hand, had exactly the opposite characteristics.     

GaAs Schottky diodes for THz mixing applications

The operation of GaAs Schottky barrier diodes, the critical mixer element used in heterodyne receivers for a variety of scientific applications in the terahertz frequency range, is reviewed. The constraints that the receiver system places on the diodes are considered, and the fundamental guidelines for device optimization are presented. The status of ongoing research, both experimental and theoretical, is examined. Emphasis is placed on investigations of the various effects that can limit diode performance at these high frequencies. Investigations of planar diode technology are summarized, and the potential replacement of whisker-contacted devices with planar structures is considered     

Curing of mixtures of epoxy resins and 4‐methyl‐1,3‐dioxolan‐2‐one with several initiators

Diglycidyl ether of bisphenol A or 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate were mixed with different proportions of 4‐methyl‐1,3‐dioxolan‐2‐one and cured using lanthanide triflates as initiators. In order to compare the materials obtained, conventional initiators such as boron trifluoride complexes and N,N‐dimethylaminopyridine were also tested. The curing process was followed by differential scanning calorimetry (DSC) and Fourier transform IR in attenuated total reflectance mode. This technique proved that the carbonate accelerates the curing process because it helps to form the active initiating species, although it was not chemically incorporated into the network and remained entrapped in the material. The DSC kinetic study was also reported. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2086–2093, 2006     

Investigation of spectral reproducibility in direct analysis of bacteria proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOFMS) can be used for rapid detection of bacteria proteins in a crude mixture. It can potentially be used as a tool for bacterial identification based on the mass spectral patterns or the appearance of some characteristic mass peaks. However, there are many experimental parameters that can potentially have a strong effect on the observed mass spectra. The objective of this work is to address the mass spectral reproducibility issue. Several experimental parameters that may affect the MALDI spectra are systematically investigated. Results of spectral comparison from two laboratories with different operators and instrumentation are presented. It is demonstrated that minor variations in the sample/matrix preparation procedures for MALDI and in the experimental conditions used for bacterial protein extraction can result in a significant change in the observed spectra, though a number of peaks are conserved in the spectra obtained under different experimental conditions from the same bacterial sample. These conserved peaks may potentially be used as the biomarkers for bacterial identification. It is stressed that this type of investigation on spectral reproducibility should be carried out for different bacterial species in order to identify the mass spectral peaks that are consistently detected regardless of operator and nominal variations in sample preparation approach.     

Dissociating Processes Supporting Causal Perception and Causal Inference in the Brain.

An understanding of relations between causes and effects is essential for making sense of the dynamic physical world. It has been argued that this understanding of causality depends on both perceptual and inferential components. To investigate whether causal perception and causal inference rely on common or on distinct processes, the authors tested 2 callosotomy (split-brain) patients and a group of neurologically intact participants. The authors show that the direct perception of causality and the ability to infer causality depend on different hemispheres of the divided brain. This finding implies that understanding causality is not a unitary process and that causal perception and causal inference can proceed independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Micro-computed tomography scanning approaches to quantify,parameterize and visualize bioturbation activity in clogged streambeds: A proof of concept

Fine particle clogging and faunal bioturbation are two key processes co-occurring in the hyporheic zone that potentially affect hyporheic exchange through modifications in the sediment structure of streambeds. Clogging results from excessive fine sediment infiltration and deposition in rivers, and it is known to decrease matrix porosity and potentially reduce permeability. Faunal bioturbation activity may compensate for the negative effect of clogging by reworking the sediment, increasing porosity, and preventing further infiltration of fines. Although both processes of clogging and bioturbation have received significant attention in the literature separately, their combined effects on streambed sediment structure are not well understood, mostly due to the lack of a standard methodology for their assessment. Here, we illustrate a novel methodology using X-ray computed tomography (CT), as proof of concept, to investigate how, together, clogging and bioturbation affect streambed porosity in a controlled flow-through flume. By visualising gallery formations of an upward conveyor macroinvertebrate; Lumbriculus variegatus as a model species, we quantified bioturbation activity in a clogged streambed, focusing on orientation, depth, and volume at downwelling and upwelling areas of the flume. Gallery creation increased the porosity of the streambed sediment, suggesting a potential improvement in permeability and a possible offset of clogging effects. We illustrate the promising use of X-ray CT as a tool to assess bioturbation in clogged streambeds, and the potential role of bioturbation activity supporting hyporheic exchange processes in streambeds, warranting further studies to understand the extent of bioturbation impacts in natural systems.