253 research outputs found
Effects of Orthogonal Rotating Electric Fields on Electrospinning Process
Electrospinning is a nanotechnology process whereby an external electric
field is used to accelerate and stretch a charged polymer jet, so as to produce
fibers with nanoscale diameters. In quest of a further reduction in the cross
section of electrified jets hence of a better control on the morphology of the
resulting electrospun fibers, we explore the effects of an external rotating
electric field orthogonal to the jet direction. Through extensive particle
simulations, it is shown that by a proper tuning of the electric field
amplitude and frequency, a reduction of up to a in the aforementioned
radius can be obtained, thereby opening new perspectives in the design of
future ultra-thin electrospun fibres. Applications can be envisaged in the
fields of nanophotonic components as well as for designing new and improved
filtration materials.Comment: 22 pages, 8 figure
Physical properties of SrSn4 single crystals
We present detailed thermodynamic and transport measurements on single
crystals of the recently discovered binary intermetallic superconductor, SrSn4.
We find this material to be a slightly anisotropic three-dimensional,
strongly-coupled, possibly multi-band, superconductor. Hydrostatic pressure
causes a decrease in the superconducting transition temperature at the rate of
-0.068 K/kbar. Band structure calculations are consistent with experimental
data on Sommerfeld coefficient and upper superconducting critical field
anisotropy and suggest complex, multi-sheet Fermi surface formed by four bands.Comment: Figure 11 correcte
Unbiased Characterization of Peptide-HLA Class II Interactions Based on Large-Scale Peptide Microarrays; Assessment of the Impact on HLA Class II Ligand and Epitope Prediction
Human Leukocyte Antigen class II (HLA-II) molecules present peptides to T lymphocytes and play an important role in adaptive immune responses. Characterizing the binding specificity of single HLA-II molecules has profound impacts for understanding cellular immunity, identifying the cause of autoimmune diseases, for immunotherapeutics, and vaccine development. Here, novel high-density peptide microarray technology combined with machine learning techniques were used to address this task at an unprecedented level of high-throughput. Microarrays with over 200,000 defined peptides were assayed with four exemplary HLA-II molecules. Machine learning was applied to mine the signals. The comparison of identified binding motifs, and power for predicting eluted ligands and CD4+ epitope datasets to that obtained using NetMHCIIpan-3.2, confirmed a high quality of the chip readout. These results suggest that the proposed microarray technology offers a novel and unique platform for large-scale unbiased interrogation of peptide binding preferences of HLA-II molecules
Empirical Investigation on Agile Methods Usage: Issues Identified from Early Adopters in Malaysia
Agile Methods are a set of software practices that can help to produce products faster and at the same time deliver what customers want. Despite the benefits that Agile methods can deliver, however, we found few studies from the Southeast Asia region, particularly Malaysia. As a result, less empirical evidence can be obtained in the country making its implementation harder. To use a new method, experience from other practitioners is critical, which describes what is important, what is possible and what is not possible concerning Agile. We conducted a qualitative study to understand the issues faced by early adopters in Malaysia where Agile methods are still relatively new. The initial study involves 13 participants including project managers, CEOs, founders and software developers from seven organisations. Our study has shown that social and human aspects are important when using Agile methods. While technical aspects have always been considered to exist in software development, we found these factors to be less important when using Agile methods. The results obtained can serve as guidelines to practitioners in the country and the neighbouring regions
Transethnic analysis of the human leukocyte antigen region for ulcerative colitis reveals not only shared but also ethnicity-specific disease associations
Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Genetic association studies have identified the highly variable human leukocyte antigen (HLA) region as the strongest susceptibility locus for IBD, and specifically DRB1*01:03 as a determining factor for ulcerative colitis (UC). However, for most of the association signal such a delineation could not be made due to tight structures of linkage disequilibrium within the HLA. The aim of this study was therefore to further characterize the HLA signal using a trans-ethnic approach. We performed a comprehensive fine mapping of single HLA alleles in UC in a cohort of 9,272 individuals with African American, East Asian, Puerto Rican, Indian and Iranian descent and 40,691 previously analyzed Caucasians, additionally analyzing whole HLA haplotypes. We computationally characterized the binding of associated HLA alleles to human self-peptides and analysed the physico-chemical properties of the HLA proteins and predicted self-peptidomes. Highlighting alleles of the HLA-DRB1*15 group and their correlated HLA-DQ-DR haplotypes, we identified consistent associations across different ethnicities but also identified population-specific signals. We observed that DRB1*01:03 is mostly present in individuals of Western European descent and hardly present in non-Caucasian individuals. We found peptides predicted to bind to risk HLA alleles to be rich in positively charged amino acids such. We conclude that the HLA plays an important role for UC susceptibility across different ethnicities. This research further implicates specific features of peptides that are predicted to bind risk and protective HLA proteins
Botulinum toxin treatment of spasticity in diplegic cerebral palsy : a randomised, double-blind, placebo-controlled, dose-ranging study
This study evaluated the efficacy and safety of three doses of botulinum toxin A (BTX-A; Dysport®) in 125 patients (meanage 5.2 years, SD 2; 54% male)with dynamic equinusspasticity during walking. Participants were randomized toreceive Dysport (10, 20, or 30 units/kg) or placebo to thegastrocnemius muscle of both legs. Muscle length wascalculated from electrogoniometric measurements and thechange in the dynamic component of gastrocnemiusshortening at four weeks was prospectively identified as theprimary outcome measure. All treatment groups showedstatistically significant decreases in dynamic componentcompared with placebo at 4 weeks. Mean improvement indynamic component was most pronounced in the 20 units/kggroup, being equivalent to an increase in dorsiflexion with the knee extended at 19°, and was still present at 16 weeks. The safety profile of the toxin appears satisfactory
The earliest thymic T cell progenitors sustain B cell and myeloid lineage potential
The stepwise commitment from hematopoietic stem cells in the bone marrow to T lymphocyte-restricted progenitors in the thymus represents a paradigm for understanding the requirement for distinct extrinsic cues during different stages of lineage restriction from multipotent to lineage-restricted progenitors. However, the commitment stage at which progenitors migrate from the bone marrow to the thymus remains unclear. Here we provide functional and molecular evidence at the single-cell level that the earliest progenitors in the neonatal thymus had combined granulocyte-monocyte, T lymphocyte and B lymphocyte lineage potential but not megakaryocyte-erythroid lineage potential. These potentials were identical to those of candidate thymus-seeding progenitors in the bone marrow, which were closely related at the molecular level. Our findings establish the distinct lineage-restriction stage at which the T cell lineage-commitment process transits from the bone marrow to the remote thymus. © 2012 Nature America, Inc. All rights reserved
Angewandte Chemie
Extended Abstract Electrospinning has been recognized as an effective and inexpensive technique for fabrication of long fibers from various materials including polymers, composites and biomacromolecules with diameters ranging from a few nanometers to few micrometers Polymer-based drug delivery systems are used to improve the therapeutic properties of drugs in a safer, effective and reliable manner Gelatin is a natural biopolymer derived from animal collagen, having a long history of safe use in pharmaceuticals, cosmetics as well as food products In the current work electrospun fibers were developed as a new system for the delivery and release of an anticancer agent doxorubicin via electrospinning technique. The morphology of the fibers was analyzed by scanning electron microscopy(SEM), fourier transform infrared spectroscopy (FTIR). The fibers were made from gelatin as a biodegradable polymer and the release of doxorubicin was followed by UV-vis spectroscopy in phosphate buffer of pH 7.4 at 25 °C and 37 °C. The release profiles from gelatin electrospun fiber mats were compared with casting films with the same composition
Evaluation of physico-chemical characteristics of fresh, refrigerated and frozen Lacaune ewes' milk
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