Baseline Assessment of 25-Hydroxyvitamin D Reference Material and Proficiency Testing/External Quality Assurance Material Commutability: A Vitamin D Standardization Program Study.

The Vitamin D Standardization Program (VDSP) coordinated a study in 2012 to assess the commutability of reference materials and proficiency testing/external quality assurance materials for total 25-hydroxyvitamin D [25(OH)D] in human serum, the primary indicator of vitamin D status. A set of 50 single-donor serum samples as well as 17 reference and proficiency testing/external quality assessment materials were analyzed by participating laboratories that used either immunoassay or LC-MS methods for total 25(OH)D. The commutability test materials included National Institute of Standards and Technology Standard Reference Material 972a Vitamin D Metabolites in Human Serum as well as materials from the College of American Pathologists and the Vitamin D External Quality Assessment Scheme. Study protocols and data analysis procedures were in accordance with Clinical and Laboratory Standards Institute guidelines. The majority of the test materials were found to be commutable with the methods used in this commutability study. These results provide guidance for laboratories needing to choose appropriate reference materials and select proficiency or external quality assessment programs and will serve as a foundation for additional VDSP studies.

Baseline Assessment of 25-Hydroxyvitamin D Assay Performance: A Vitamin D Standardization Program (VDSP) Interlaboratory Comparison Study.

The Vitamin D Standardization Program (VDSP) coordinated an interlaboratory study to assess the comparability of measurements of total 25-hydroxyvitamin D [25(OH)D] in human serum, which is the primary marker of vitamin D status. A set of 50 individual donor samples were analyzed by 15 different laboratories representing national nutrition surveys, assay manufacturers, and clinical and/or research laboratories to provide results for total 25(OH)D using both immunoassays (IAs) and LC tandem MS (MS/MS). The results were evaluated relative to bias compared with the target values assigned based on a combination of measurements at Ghent University (Belgium) and the U.S. National Institute of Standards and Technology using reference measurement procedures for the determination of 25(OH)D2 and 25(OH)D3. CV and mean bias for each laboratory and assay platform were assessed and compared with previously established VDSP performance criteria, namely CV ≤ 10% and mean bias ≤ 5%. Nearly all LC-MS/MS results achieved VDSP criteria, whereas only 50% of IAs met the criterion for a ≤10% CV and only three of eight IAs achieved the ≤5% bias. These results establish a benchmark for the evaluation of 25(OH)D assay performance and standardization activities in the future.

Reduction of tail state on boron doped hydrogenated amorphous silicon oxide films prepared at high hydrogen dilution.

In this report, we have investigated on the defect state of diborane (B2H6) doped wide bandgap hydrogenated amorphous silicon oxide (p-type a-SiO:H) films prepared using silane (SiH4), hydrogen (H2) and nitrous oxide (N2O) in a radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) system with different hydrogen dilutions. The films prepared with higher hydrogen dilution show lower Urbach energy (Eu), lower microstructure (R*), lower short and medium range disorder (omegaTO, Gamma(TO), I(TA)/I(TO), I(LA)/I(TO)), higher dark conductivity (sigma d) and higher refractive index (n) with high optical gap (Eg). Eu decreases from 248 meV to 153 meV, and R* decreases from 0.46 to 0.26, Raman peak omegaTO-TO mode position shifts from 480.24 to 483.28, GammaTO-full width half maximum of omegaTO decreases from 78.16 to 63.87, I(TA)/I(TO)-the ratio of integrated area of TA and TO mode decreases from 0.624 to 0.474, I(LA)/I(TO)-the ratio of integrated area of LA and TO mode deceases from 0.272 to 0.151, sigma d increases from 4.6 x 10(-7) S/cm to 1.1 x 10(-6) S/cm, n increases from 3.70 to 3.86. Reduced Nd, Eu and R* at wide Eg indicates that the films are more useful for solar cell window layer. Applying this layer to a single junction solar cell shows open circuit voltage (Voc) = 0.80 V, short circuit current density (Jsc) = 16.3 mA/cm2, fill factor (FF) = 72%, efficiency (eta) = 9.4%.

Spectroscopic ellipsometry analysis of amorphous silicon thin films for Si-nanocrystals.

Hydrogenated amorphous and nano-crocrystalline silicon thin films were grown by very-high-frequency plasma-enhanced chemical vapor deposition (VHF-PECVD, 60 MHz). In this paper, we report the defects of nano-crystallites embedded in an amorphous matrix of hydrogenated silicon alloy (a-Si:H) thin film as investigated by spectroscopic ellipsometry (SE). The peak intensity and position of the imaginary part of the dielectric constant (epsilon2) as a function of the energy show various material states, including a-Si:H (3.5 eV) and nc-Si (4.2 eV), along with the absorption coefficient, thickness, optical gap, and the characteristics of the defects. The ratio of the characteristic Raman features, the TA/LO and LA/LO ratio, is related to the defect states in the films. It was correlated to the SE data. Following this, we look into the systematic change in the crystallinity of the film from the SE results. Quantized crystallinity values from the SE data show good agreement by more than 88.75% with the crystallinity information obtained through Raman spectroscopy.

Enhanced detection of enteroviruses in clinical samples by reverse transcription-PCR using complementary locked primer technology.

To increase detection sensitivity, we modified primers using complementary locked primer (CLP) technology. The sensitivity of the reverse transcription-PCR (RT-PCR) with CLP-modified primers was 10- to 100-fold higher than that of RT-PCR without these primers. CLP-modified primers can increase sensitivity, providing a widely accessible method for molecular diagnosis.

A peculiar multiple polypoid mucosal prolapse causing jejunal intussusception.

A case of jejunal intussusception caused by a multiple polypoid mucosal prolapse of jejunum in a 10-year-old girl is reported. The rarity of the lesion, its location, symptoms, and diagnosis are discussed.