Mechanistic study on hydration and drug release behavior of sodium alginate compacts

The influence of sodium alginate viscosity on the dynamics of matrix hydration, solvent front movement, swelling, erosion, and drug release from alginate matrix tablets were examined. The solvent front showed preferential penetration from the radial direction even though matrix swelling showed axial predominance. This study proposed alternative views for the anisotropic behavior of hydrating alginate compacts, namely, formation of gel barrier with different permeability characteristics, tension at the gel-core interface and preferential radial erosion, in addition to an in-depth examination on the contribution of stress relaxation of hydrated polymer as well as core expansion. Alginate matrices demonstrated pH-dependent hydration, swelling and erosion behavior, resulting in pH-dependent drug release mechanisms. Dissolution profiles for alginate matrices of different viscosities were similar in acid but differed upon increase of pH. This was due to the influence of alginate viscosity grade on liquid uptake, erosion and pronounced swelling at near neutral pH.     

Record 12.34% stabilized conversion efficiency in a large area thin‐film silicon tandem (MICROMORPH™) module

Mass‐adoption of thin‐film silicon (TF‐Si) photovoltaic modules as a renewable energy source can be viable if the cost of electricity production from the module is competitive with conventional energy solutions. Increased module performance (electrical power generated) is an approach to reduce this cost. Progress towards higher conversion efficiencies for ‘champion’ large area modules paves the way for mass‐production module performance to follow. At TEL Solar AG, Trübbach, Switzerland, significant progress in the absolute stabilized module conversion efficiency has been achieved through optimized solar cell design that integrates high‐quality amorphous and microcrystalline TF‐Si‐deposited materials with efficient light management and transparent conductive oxide layers in a tandem MICROMORPH™ module. This letter reports a world record large area (1.43 m²) stabilized module conversion efficiency of 12.34% certified by the European Solar Test Installation; an increase of more than 1.4% absolute compared with the previous record for a TF‐Si triple junction large area module. This breakthrough result generates more than 13.2% stabilized efficiency from each equivalent 1 cm² of the active area of the full module. Copyright © 2015 John Wiley & Sons, Ltd.     

Platelet-Activating Factor Quantification Using Reversed Phase Liquid Chromatography and Selected Reaction Monitoring in Negative Ion Mode

Platelet‐activating factor (PAF) is a potent biologically active phospholipid that mediates human physiological and pathophysiologic responses. PAF levels increase transiently and are typically assessed by techniques with limitations related to expense, sensitivity, pre‐analysis derivatization and interference with isobaric molecules. This study elucidates a facile, accurate liquid chromatography–mass spectrometry analytical method for PAF. In negative ion mode using electrospray ionization, collisionally‐activated dissociation analysis showed a unique product ion for acetate adducts of PAF molecular species representing the loss of methyl acetate from the polar head group and loss of a part of the acetate group from the sn‐2 position. This product ion was exploited for selected reaction monitoring of PAF molecular species following separation by reversed‐phase liquid chromatography. Standard calibration responses were determined, and this method was able to detect as low as 100 fmol of PAF. Finally, PAF molecular species were quantified in human neutrophils and monocytes.     

O6-Methylguanine-Methyltransferase (MGMT) Promoter Methylation Status in Glioma Stem-Like Cells is Correlated to Temozolomide Sensitivity Under Differentiation-Promoting Conditions

Glioblastoma (GBM) is the most malignant type of primary brain tumor with a very poor prognosis. The actual standard protocol of treatment for GBM patients consists of radiotherapy and concomitant temozolomide (TMZ). However, the therapeutic efficacy of this treatment is limited due to tumor recurrence and TMZ resistance. Recently isolated, glioma stem-like cells (GSCs) are thought to represent the population of tumorigenic cells responsible for GBM resistance and recurrence following surgery and chemotherapy. In addition, MGMT (O6-methylguanine-methyltransferase) methylation is considered as one of the principal mechanisms contributing to TMZ sensitivity of GBM. In this study we have isolated GSCs from 10 adult GBM patients and investigated the relationship between MGMT methylation status and Temozolomide (TMZ) sensitivity of these lines grown either in stem-like or differentiation promoting conditions. Sensitivity to TMZ was significantly associated with MGMT methylation status in cells committed to differentiation but not in stem-like cells. In addition, patients harboring highly methylated MGMT promoters had a longer overall survival. These results reveal the importance of the differentiation process when considering the predictive value of MGMT status in GSCs for clinical response to TMZ.     

Changes in nutritional and sensory properties of orange juice packed in PET bottles: An experimental and modelling approach

Sensitivity to oxidation of an orange juice was investigated through packaging in standard PET or active PET with oxygen scavenger bottles. The evolution of dissolved oxygen was found to be similar in all bottles, whereas ascorbic acid degradation was related to the oxygen transfer with higher losses in standard PET (53%) against active PET (31%). Moreover, when juice was exposed to high intensity light, a fold faster degradation of ascorbic acid was observed compared to total darkness. Depending also on the light intensity and regardless of the package permeability, changes in the aromatic profile of the juice were observed due to the degradation of limonene and the formation of α-terpineol, an off-flavour. A mechanistic model was developed to predict the shelf life of orange juice. This model, coupling O₂ transfer and ascorbic acid oxidation reaction in the bottled juice, confirmed that oxygen permeation through packaging material could not be neglected.     

Seven thousand years of records on the mining and utilization of metals from lake sediments in central China

A 268 cm section of sediment core from Liangzhi Lake in Hubei province in central China was used to assess the use and accumulation of metals in the lake in the past 7,000 years. The concentrations of trace metals, including Cu, Pb, Ni, and Zn, and major elements, Ca, Fe, and Mg, in a 14C- dated segment of sediment core were analyzed. Historical trends on the input of metals to Liangzhi Lake from around 5000 BC to the present were recorded in the sediments, representing about 7,000 years of history on the mining and utilization of metals in central China. The concentrations of Cu, Ni, Pb, and Zn increased gradually from about 3000 +/- 328 BC, indicating the start of the Bronze Age in ancient China. During the period 467 +/- 257 to 215 +/- 221 AD, there was a rapid increase in the concentrations of these metals in the sediments, indicating enormous inputs of these metals at that time. This era corresponded to China's Warring States Period (475- 221 BC) and the early Han Dynasty (206 BC-220 AD), during which copper and lead were extensively used in making bronze articles such as vessels, tools, and weapons. From 1880 +/- 35 AD to the early 1900s, there was also a significant increase in the concentrations of metals such as Cu, Ni, and Pb, which probably reflected the metal emissions and utilization during the early period of industrial development and weapon manufacture during the wars in China. The Pb isotopic analysis showed that the surface and subsurface sediments had lower 206Pb/207Pb and 208Pb/ 207Pb ratios than the deeper layers, reflecting the additional input of Pb from mining activities that took place during the Bronze Age era and in modern times. This study provides direct evidence of the environmental impact of the mining and utilization of metals in the last 7,000 years in one of the important regions of Chinese civilization.     

A novel chemometric classification for FTIR spectra of mycotoxin-contaminated maize and peanuts at regulatory limits

The rapid identification of mycotoxins such as deoxynivalenol and aflatoxin B₁ in agricultural commodities is an ongoing concern for food importers and processors. While sophisticated chromatography-based methods are well established for regulatory testing by food safety authorities, few techniques exist to provide a rapid assessment for traders. This study advances the development of a mid-infrared spectroscopic method, recording spectra with little sample preparation. Spectral data were classified using a bootstrap-aggregated (bagged) decision tree method, evaluating the protein and carbohydrate absorption regions of the spectrum. The method was able to classify 79% of 110 maize samples at the European Union regulatory limit for deoxynivalenol of 1750 µg kg^–1 and, for the first time, 77% of 92 peanut samples at 8 µg kg^–1 of aflatoxin B₁. A subset model revealed a dependency on variety and type of fungal infection. The employed CRC and SBL maize varieties could be pooled in the model with a reduction of classification accuracy from 90% to 79%. Samples infected with Fusarium verticillioides were removed, leaving samples infected with F. graminearum and F. culmorum in the dataset improving classification accuracy from 73% to 79%. A 500 µg kg^–1 classification threshold for deoxynivalenol in maize performed even better with 85% accuracy. This is assumed to be due to a larger number of samples around the threshold increasing representativity. Comparison with established principal component analysis classification, which consistently showed overlapping clusters, confirmed the superior performance of bagged decision tree classification.     

Case of Mycobacterium mucogenicum in a home hemodialysis patient

We present a case of a patient on home hemodialysis who developed Mycobacterium mucogenicum bacteremia. While infections with this particular organism are rare, disseminated infections have been reported and have been associated with significant morbidity and mortality. Diagnosis required appropriate cultures, understanding of natural habitat of organism and complete environmental analysis including blood, dialysis sample port, reverse osmosis and incoming water supply cultures. The patient was treated successfully with systemic antibiotics, removal of central venous catheter, patient education and complete exchange of the hemodialysis circuit.     

Are self-report measures of dyadic relationships influenced by impression management biases?

This study systematically examined the effects of impression management biases on the reporting of dyadic relationship information. In an anonymous mail survey, 196 participants (101 women, 95 men) in marital or cohabiting relationships completed a measure of impression management and several relationship measures. Analyses indicated that impression management biases did not affect women's self-reports. Among men, impression management biases were significantly associated with many of their reports about their relationships. However, statistically controlling for these biases did not reduce the magnitude of correlations between measures of marital quality and the other relationship measures. Furthermore, partners' agreement about observable aspects of their relationship did not change when the influences of these biases were statistically removed. The authors conclude that researchers can generally trust in the veridicality of anonymous self-report data about commonplace aspects of marriage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Coherent radiance capture of scenes under changing illumination conditions for relighting applications

Relighting algorithms make it possible to take a model of a real-world scene and virtually modify its lighting. Unlike other methods that require controlled conditions, we introduce a new radiance capture method that allows the user to capture parts of the scene under different lighting conditions. A novel calibration method is presented that finds the positions of reflective spheres and their mathematically accurate projection onto the scene geometry. The resulting radiance distribution is used to estimate a diffuse reflectance for each object, computed coherently using the appropriate light probe image. Finally, the scene is relit using a novel illumination pattern.