Crystal and electronic structure of PbTe/CdTe nanostructures

In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix. The structural properties are studied by ab initio methods. A tight-binding model is constructed to calculate the electron density of states (DOS) of the systems. In contrast to the ab initio methods, the latter allows studying nanostructures with diameters comparable to the real ones. The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material. These changes depend on the size, shape, and concentration of inclusions.     

Stabilization of butter with deodorized rosemary extract

 The antioxidative activity of the ethanolic extract of deodorized rosemary (Rosmarinus officinalis L.) in butter was tested. The extract was added at two concentrations, 0.05 and 0.1%, to the cream before churning. The samples of isolated fat were stored at 60°C for 38 days and their peroxide values (PVs) determined periodically. The relative changes in the proton absorption patterns of the butter lipids during storage were monitored by nuclear magnetic resonance (NMR) spectroscopy. The samples treated with 0.05 and 0.1% extract had much longer induction periods than the control. A significant correlation (r = 0.980) was measured between the ratio of aliphatic to olefinic protons (R _ao) and the PVs of the butter fat. The deodorized ethanolic extract was also subjected to TLC separation on silica gel plates and UV spectral analysis. The UV spectrum of the extract had maxima at 286 and 328 nm. Six spots attributed to phenolic compounds were observed on the TLC plate. The extract also exhibited strong antioxidant activity in a β-carotene-linoleate model system. Received: 11 July 1997     

Slaughter value and flesh characteristics of European catfish (Silurus glanis) fed natural and formulated feed under different rearing conditions

The experimental material was comprised of European catfish (Silurus glanis) individuals aged 2.5 years that were reared on natural feed in earthen ponds and individuals aged 1.5 years cultivated intensively on formulated feed in recirculating systems. Weight gain and morphometric parameters were measured along with physical and color characteristics and proximate composition of fillets. Despite the different age and diets of the fish, no differences were observed in the linear biometric indices. The total weight of the fish of both groups and their condition coefficients were also similar. In addition, no differences were reported in their body weight or head and gutted (H&G) carcass and fillet yields. Proximate composition analysis demonstrated a lack of differences in the contents of dry matter. Of the dry matter, differences were reported in the fat content, which was higher in the catfish fed formulated feed. The color of the fillets was characterized by high values of lightness, negative values of redness, and positive values of yellowness, and the fish fed formulated feed displayed higher saturation of green. The flesh of both groups of catfish demonstrated similar pH values and water retention capacity, whereas the values of thermal drip appeared to be higher in the fish fed formulated feed.     

Comparison of High-throughput and Manual DNA Extraction Methods for the Qualitative and Quantitative Analysis of MON810 Maize

PCR-based methods are widely used in the European Union and in other countries for the detection, identification, and quantification of genetically modified organisms (GMOs). The preparation of good-quality DNA from plant samples for GMO detection can be a challenging task, particularly if the DNA will be used for quantitative analysis. Two DNA extraction methods, namely manual (NucleoSpin Food kit from Machery-Nagel) and high-throughput partially automated (NucleoMag Plant kit from Machery-Nagel) methods, which utilize different DNA separation principles, were used for the isolation of DNA from maize flour samples. Despite the higher DNA recovery obtained using the high-throughput isolation method, a lower PCR efficiency was achieved, most likely due to the presence of PCR inhibitors in the extracts. We found both DNA extraction methods suitable for GMO analysis.     

Melnikov Functions in Quadratic Perturbations of Generalized Lotka–Volterra Systems

Journal of Dynamical and Control Systems - We present a detailed analysis of Melnikov functions which arise in quadratic perturbations of generalized Lotka–Volterra vector fields with the...     

Protein-precipitating capacity of bearberry-leaf (Arctostaphylos uva-ursi L. Sprengel) polyphenolics

Polyphenolics (PP) from bearberry (Arctostaphylos uva-ursi L. Sprengel) leaves were extracted with 70% (v/v) acetone. The lyophilised crude PP extract was then separated on a Sephadex LH-20 column using first 95% (v/v) ethanol as a mobile phase to elute fraction I low in tannins, and then 50% (v/v) acetone to elute fraction II rich in hydrolysable and condensed tannins. Bovine serum albumin (BSA) was effectively precipitated by PP in the bearberry-leaf crude extract and fraction II at pH values between 3.8 and 4.5. A statistically significant (P = 0.0001) linear relationship exists between the amount of PP-protein complex formed and the quantity of PP added to the reaction mixture. The slope values of these lines indicate that fraction II from the crude extract was a more effective precipitant of proteins than other examined preparations. Based on the quantity of gelatine, fetuin, and BSA required to inhibit 50% of dye-labelled PP–BSA complex precipitation, gelatine was 3–6 times more effective as a precipitation inhibitor than both unlabelled BSA and fetuin.     

Isolation and some properties of collagen from the backbone of Baltic cod (Gadus morhua)

Ossein from Baltic cod backbone was obtained after extraction of non-collagenous protein with 0.1 M NaOH solution and demineralization with 1.0 M HCl solution. The extractions were performed at 4 °C for 24, 48 and 72 h using a solid/solution ratio from 1:4 to 1:8 (w/v). After 48 h of extraction in 0.5 M acetic acid only about 25% of collagen was dissolved. After 48 h of extraction at optimal concentration of pepsin (4 mg/g ossein) the collagen was dissolved almost completely. Collagen solubilized in acetic acid could be almost completely precipitated with κ-carrageenan, at protein/polysaccharide ratio 1:1 (w:w). The denaturation temperature of Baltic cod backbone collagen was 14.4 °C and the conversion factor of hydroxyproline to collagen was 15.7.