Effect of gamma-radiation on a water-insoluble arabinoxylan

The effect of gamma radiation on a water-insoluble L-arabino-D-xylan has been studied by functional group and structural analysis using chemical methods and IR spectroscopy, by sugar composition analysis, and by viscosity measurements. The gamma irradiation has been shown to modify both sugar components of the arabinoxylan, accompanied by cleavage of the glycosidic linkages, depolymerization, and sugar decomposition, depending on the applied radiation dose, thus increasing the molecular and chemical heterogeneity of the polysaccharide.     

X-ray study of pre-treated regenerated cellulose fibres

Regenerated cellulose fibres have had an important role to play in the man-made fibre field. The very special characteristics of different types of regenerated cellulose fibres, e.g. mechanical properties, sorption characteristics, and aesthetics were conditioned by the differences in their fine structure due to fibre formation processes. Additionally, the finishing processes could influence the fibre structure. A study was done of the crystalline structures of a solvent-spun cellulose fibre type (Lenzing Lyocell), made according to the NMMO process, and two conventional cellulosic fibre types, made by the viscose process (Lenzing Viscose and Lenzing Modal). The fibres were pre-treated (bleached and slack mercerised) and structural changes were followed by wide angle and small angle x-ray scattering (WAXS and SAXS), respectively. The periodical structure, determined by long spacing, was nearly the same in all the different types of fibres. A slight increase was observed after the treatment of viscose and modal fibres, but an unpronounced fall of a long period accompanied the pre-treatment of lyocell fibres. Some changes in crystallinity and crystalline orientation occurred due to the treatment conditions. The structural changes were correlated to the iodinesorption and mechanical properties.     

Selective sample cleanup by reusable sol-gel immunoaffinity columns for determination of deoxynivalenol in food and feed samples

The paper describes the development of a simple and highly selective method for the determination of deoxynivalenol (DON) in food and feed samples. It combines sample cleanup with sol-gel immunoaffinity columns containing monoclonal anti-DON antibodies and quantification of DON by high-performance liquid chromatography with ultraviolet detection. The sol-gel immunoaffinity columns are as selective as commercial DON immunoaffinity columns but superior with regard to production costs, storage stability, and reusability. In applying the method for the analysis of maize, wheat, and spaghetti samples, it offers detection limits (LOD, S/N = 3) of 240, 200, and 207 ng/g, and recoveries of 83, 99, and 97%, respectively.     

Speciation of inorganic arsenic in some bottled Slovene mineral waters using HPLC-hGAFS and selective coprecipitation combined with FI-HGAFS

Five bottled mineral waters from the Radenska and the Rogaska springs (Slovenia) were analyzed for their inorganic arsenic species As(III) and As(V) using existing speciation procedures. Both a hyphenated technique (HPLC-HGAFS) and a more conventional technique based on selective coprecipitation of As(III) with dibenzyldithiocarbamate prior to arsenic analysis (FI-HGAFS) were used. The techniques yielded data which were not significantly different on the 5% level, with HPLC-HGAFS to be the least sensitive (DL 1 microgl(-1)) and the selective coprecipitation technique to be suitable for sub pgl(-1) levels (DL 0.05 microgl(-1)). The latter technique showed recoveries of 96.4 +/- 0.4%. In none of the mineral waters As(III) was found whereas the Radenska minerals waters (vrelec Radin vrelec Miral, Kraljevi Vrelec) contained little As(V) (only detectable with the selective coprecipitation technique) and the Rogaska mineral waters (Tempel, Donat Mg) (very) high As(V) concentrations. Rogaska, Donat Mg even had an average As(V) concentration around the permittable level of 50 microgl(-1) for arsenic in minerals waters, viz. 47.8 microg l(-1). Speciation calculations based on pH and Eh and taking into account the ionic strength gave a similar speciation pattern then speciation analysis with additional information about the degree of protonation of As(III) and As(V).     

Hierarchically Structured Polystyrene-Based Surfaces Amplifying Fluorescence Signals: Cytocompatibility with Human Induced Pluripotent Stem Cell

An innovative multi-step phase separation process was used to prepare tissue culture for the polystyrene-based, hierarchically structured substrates, which mimicked in vivo microenvironment and architecture. Macro- (pore area from 3000 to 18,000 µm²; roughness (Ra) 7.2 ± 0.1 µm) and meso- (pore area from 50 to 300 µm²; Ra 1.1 ± 0.1 µm) structured substrates covered with micro-pores (area around 3 µm²) were prepared and characterised. Both types of substrate were suitable for human-induced pluripotent stem cell (hiPSC) cultivation and were found to be beneficial for the induction of cardiomyogenesis in hiPSC. This was confirmed both by the number of promoted proliferated cells and the expressions of specific markers (Nkx2.5, MYH6, MYL2, and MYL7). Moreover, the substrates amplified the fluorescence signal when Ca²⁺ flow was monitored. This property, together with cytocompatibility, make this material especially suitable for in vitro studies of cell/material interactions within tissue-mimicking environments.     

Plasma modification of viscose textile

A study on plasma treatment of a textile is presented. Samples of pure viscose textile were exposed to RF oxygen, nitrogen or hydrogen plasma for 5 s. The gas pressure was 75 Pa and the RF power was 250 W. In all cases plasma treatment induced chemical changes in the samples' surface, which were determined by using high-resolution XPS (X-ray photoelectron spectrometer). Treatments in oxygen and nitrogen plasma increased the concentration of existing as well as formation of oxygen functional groups, while hydrogen plasma caused a substantial decrease of these groups. SEM (Scanning electron microscopy) analysis of the surface of the textile fibres was performed as well. The results showed that the fibres' surface treated in nitrogen plasma was similar to the untreated surface, while after treatment in hydrogen or oxygen plasma, the surface became rougher.     

Obesity-Related Neuroinflammation: Magnetic Resonance and Microscopy Imaging of the Brain

Obesity is a major risk factor of Alzheimer’s disease and related dementias. The principal feature of dementia is a loss of neurons and brain atrophy. The mechanistic links between obesity and the neurodegenerative processes of dementias are not fully understood, but recent research suggests that obesity-related systemic inflammation and subsequent neuroinflammation may be involved. Adipose tissues release multiple proinflammatory molecules (fatty acids and cytokines) that impact blood and vessel cells, inducing low-grade systemic inflammation that can transition to tissues, including the brain. Inflammation in the brain—neuroinflammation—is one of key elements of the pathobiology of neurodegenerative disorders; it is characterized by the activation of microglia, the resident immune cells in the brain, and by the structural and functional changes of other cells forming the brain parenchyma, including neurons. Such cellular changes have been shown in animal models with direct methods, such as confocal microscopy. In humans, cellular changes are less tangible, as only indirect methods such as magnetic resonance (MR) imaging are usually used. In these studies, obesity and low-grade systemic inflammation have been associated with lower volumes of the cerebral gray matter, cortex, and hippocampus, as well as altered tissue MR properties (suggesting microstructural variations in cellular and molecular composition). How these structural variations in the human brain observed using MR imaging relate to the cellular variations in the animal brain seen with microscopy is not well understood. This review describes the current understanding of neuroinflammation in the context of obesity-induced systemic inflammation, and it highlights need for the bridge between animal microscopy and human MR imaging studies.     

Deleterious Effects of Hyperactivity of the Renin-Angiotensin System and Hypertension on the Course of Chemotherapy-Induced Heart Failure after Doxorubicin Administration: A Study in Ren-2 Transgenic Rat

Doxorubicin’s (DOX) cardiotoxicity contributes to the development of chemotherapy-induced heart failure (HF) and new treatment strategies are in high demand. The aim of the present study was to characterize a DOX-induced model of HF in Ren-2 transgenic rats (TGR), those characterized by hypertension and hyperactivity of the renin-angiotensin-aldosterone system, and to compare the results with normotensive transgene-negative, Hannover Sprague-Dawley (HanSD) rats. DOX was administered for two weeks in a cumulative dose of 15 mg/kg. In HanSD rats DOX administration resulted in the development of an early phase of HF with the dominant symptom of bilateral cardiac atrophy demonstrable two weeks after the last DOX injection. In TGR, DOX caused substantial impairment of systolic function already at the end of the treatment, with further progression observed throughout the experiment. Additionally, two weeks after the termination of DOX treatment, TGR exhibited signs of HF characteristic for the transition stage between the compensated and decompensated phases of HF. In conclusion, we suggest that DOX-induced HF in TGR is a suitable model to study the pathophysiological aspects of chemotherapy-induced HF and to evaluate novel therapeutic strategies to combat this form of HF, which are urgently needed.     

Free‐volume structure of polyvinylpyrrolidone‐capped glassy As2Se3 nanocomposites prepared by mechanical milling

The method of positron annihilation lifetime (PAL) spectroscopy was first employed to study atomic‐deficient free‐volume structure of nanocomposites prepared by high‐energy mechanical milling of glassy g‐As₂Se₃ in water solution of polyvinylpyrrolidone (PVP). The formalism of x3‐x2‐CDA (coupling decomposition algorithm) describing conversion of bound positron‐electron (positronium Ps) states into positron traps was applied to identify free‐volume elements in pelletized PVP‐capped g‐As₂Se₃ nanocomposite in respect to parent dry‐milled g‐As₂Se₃. Under wet milling, the internanoparticle Ps‐decaying sites in preferential PVP environment were shown to replace free‐volume positron traps in dry‐milled g‐As₂Se₃ with defect‐specific positron lifetime of 0.352 ns, corresponding to diatomic/triatomic vacancies in g‐As‐Se matrix. POLYM. ENG. SCI., 59:2438–2442, 2019. © 2019 Society of Plastics Engineers