Growth and characterization of l-phenylalanine nitric acid, a new organic nonlinear optical material

A new organic nonlinear optical material L-phenylalanine nitric acid [2C₉H₁₁NO₂.H⁺. NO₃⁻] (LPN), was synthesized in mixed solvent of deionised water and methanol and single crystals of LPN was grown by slow evaporation method. Transparent crystals upto 2.9 × 0.3 × 0.05 cm³ were obtained. The grown crystals have been subjected to powder X-ray diffraction studies to identify the crystalline nature. Single crystal X-ray diffractometer was utilized to measure unit cell parameters and to confirm the crystal structure. The modes of vibration of different molecular groups present in LPN were identified by FTIR spectral analysis. Transmission spectra reveals that the crystal has low UV cutoff of 295 nm and has a good transmittance in the entire visible region enabling its use in optical applications. Thermal properties of the crystals have been investigated using thermogravimetric (TG) and differential thermal analyses (DTA), which indicate that the material does not decompose before melting. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm.     

Specific recognition of HLA-E, but not classical, HLA class I molecules by soluble CD94/NKG2A and NK cells

The CD94/NKG2 receptors expressed by subpopulations of NK cells and T cells have been implicated as receptors for a broad range of both classical and nonclassical HLA class I molecules. To examine the ligand specificity of CD94/NKG2 proteins, a soluble heterodimeric form of the receptor was produced and used in direct binding studies with cells expressing defined HLA class I/peptide complexes. We confirm that CD94/NKG2A specifically interacts with HLA-E and demonstrate that this interaction is dependent on the association of HLA-E with peptide. Moreover, no interaction between CD94/NKG2A and classical HLA class I molecules was observed, as assayed by direct binding of the soluble receptor or by functional assays using CD94/NKG2A+ NK cells. The role of the peptide associated with HLA-E in the interaction between HLA-E and CD94/NKG2A was also assessed. All class I leader sequence peptides tested bound to HLA-E and were recognized by CD94/NKG2A. However, amino acid variations in class I leader sequences affected the stability of HLA-E. Additionally, not all HLA-E/peptide complexes examined were recognized by CD94/NKG2A. Thus CD94/NKG2A recognition of HLA-E is controlled by peptide at two levels; first, peptide must stabilize HLA-E and promote cell surface expression, and second, the HLA-E/peptide complex must form the ligand for CD94/NKG2A.     

Citation Counts of Multi-Authored Papers — First-named Authors and Further Authors

To examine whether primary-citation indexing can be taken as an unbiased representation of all-author indexing, we compared the cited first-author counts (straight counts) with the cited all-author counts (complete counts)in two psychological journals over two publication years. Although rather high correlations were found between straight counts and complete counts, correlations differ with journals of the same discipline, with different publication years of the same journal, and according to seniority of cited authors. No effect of alphabetical name ordering was found. Results are discussed against the background of the possible use of weighting procedures for all-author indexing. This revised version was published online in June 2006 with corrections to the Cover Date.     

Bernard H. Fox (1917-2001).

Memorializes B. H. Fox, a research scientist internationally known for his work on the epidemiology and etiology of cancer. Fox was instrumental in establishing a new field of research best described as biopsychosocial cancer epidemiology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ESBL-producing E. coli in Austrian sewage sludge

The aim of this study was to investigate the degree of contamination of sewage sludge with ESBL-producing Escherichia coli strains and the effectiveness of different sewage sludge treatment methods.Monthly sewage sludge samples were collected between January and September 2009 in 5 different sewage treatment plants and tested for the presence of ESBL E. coli. In addition, the number of colony forming units (CFU) of E. coli and coliform bacteria before and after the different sludge treatment methods (aerobic/anaerobic digestion, lime stabilization, and thermal treatment) was investigated.Of the 72 sewage sludge samples investigated, ESBL-positive E. coli were found in 44 (61.1%) sewage sludge samples. The classification of β-lactamase groups was carried out in 15 strains resulting in the detection of 2 different groups (CTX-M and TEM) of bla genes. All 15 of them had a CTX-M gene and 4 of these strains furthermore carried a TEM gene.With regard to the CFU of E. coli and coliform bacteria, thermal treatment and lime stabilization following dehydration sufficiently reduced pathogen concentrations. The plants using merely stabilization and dehydration showed an increase of E. coli and coliform bacteria and thus also an increase in ESBL-producing E. coli.     

Evolution of the nutritional status of Chilean children from preschool to school age: anthropometric results according to the source of the data

Because the results of the nutritional status released by Chilean institutions which collect anthropometric data on their population under control, show different increments in the prevalence of obesity between preschoolers and children in 1st grade, we decided to verify the real magnitude of this increase. This study is based on a longitudinal investigation which began in 2006 and included 1100, three-year old children, which we evaluated when they were 4, 5 and 6 y. The nutritional status was determined according to BMI Z and WHO References 2006/2007. The information was also used to determine the concordance between the anthropometric data collected on first graders by teachers from public schools in 2009 (JUNAEB data set) and the same children assessed in parallel by INTA (INTA data set). The sample included 474, six-year olds. No differences were found between the average BMI Z and HAZ of the two data sets, and the degree of concordance between the BMI Z's was good (rho = 0.73), however there were differences in the nutritional status, since the prevalence of low weight was significantly greater when assessed with JUNAEB's data (9.5% vs. 3.6% ), while that for obesity was lower with INTA's data, 17.5% vs. 19.2% (not significantly different). At 4 and 5 y, obesity prevalence of the children was 13.3% and 15.7% respectively (INTA's data). Considering the observed nutritional trajectory, it is likely that the rise in obesity between 4 and 6 y of age, was 4 percentage points and not 6, as was determined with INTA's data.     

A two-stage capacitive-feedback differencing amplifier for temporal contrast IR sensors

This article presents a small-area, ultra low-power, low-mismatch differencing transient amplifier for ROIC pixels of micro-bolometer based temporal contrast IR sensors. The two-stage capacitive-feedback amplifier works in the sub-threshold domain, has a voltage gain of 46 dB, a 3 dB bandwidth of about 10 kHz and consumes 85 nW of static power. The amplifier circuit has been fabricated in a 0.35 μm standard CMOS process and consumes less than 2000 μm² of silicon area, enabling a square pixel size of 50 × 50 μm for the IR sensor array.