Fatty acid and carotenoid composition of egg yolk as an effect of microalgae addition to feed formula for laying hens

Hens were fed five diets based on rapeseed/corn oils with or without addition of the marine microalgae, Nannochloropsis oculata. Colours of egg yolk, fatty acid profiles in phospholipid (PL) and triacylglycerol (TAG) fractions and carotenoid contents were analysed. The major effects on yolk fatty acid composition were observed in the PL fraction with changes in 18:2n − 6, 18:3n − 3, 20:4n − 6, 20:5n − 3 and 22:6n − 3. The highest amounts of eicosapentaenoic acid and docosahexaenoic acid were obtained from the diet containing 20% N. oculata, whereas the highest arachidonic acid content in yolk was from the corn oil diet. In addition, colour (a* value) and carotenoid content increased when N. oculata was included in the diet. Long chained fatty acids were almost exclusively present in the PL fraction of yolk. This study shows that fatty acid composition and carotenoid content of egg yolk are improved by addition of N. oculata in laying hen diet.     

The effect of moisture on the dynamical mechanical properties of bacterial cellulose/glucuronoxylan nanocomposites

The plant cell wall possesses unique material properties due to its hierarchical organisation. In order to biomimic a native structure like a plant cell wall, a model system consisting of microfibrillar cellulose, produced by the gram-negative bacteria Acetobacter xylinum, and a glucuronoxylan matrix derived from aspen holocellulose was constructed. The glucuronoxylan was extracted from delignified aspen (Populus tremula) wood chips using DMSO to preserve its native chemical composition. Dynamic mechanical analysis (DMA) measurements performed with moisture scans showed a moisture-induced softening of delignified aspen wood fibres due to the plasticization of glucuronoxylan. A similar result was observed for the model system. However, the softening behaviour of the delignified aspen fibre and the model system was not identical, most probably due to differences in spatial organisation of the components. Dynamic FTIR-studies indicated that interactions between the cellulose and the glucuronoxylan exist in the aspen holocellulose while the components in the nanocomposite appear to be more isolated.     

Safety evaluation of slender high-strength concrete columns under sustained loads

A realistic analysis of the reliability of slender high-strength concrete (HSC) columns must include the long-term effects of sustained loads. In this paper, the long-term reliability of eccentrically loaded slender HSC columns under sustained loads is evaluated. The reliability of slender reinforced concrete columns representing normal-strength concrete and HSC is investigated. Since most of the variables involved in column design (material properties, geometric characteristics, loads, etc.) are random, probabilistic methods are used in the analysis. The effects of the concrete compressive strength, amount of longitudinal steel, load eccentricity, and slenderness ratio on the column reliability are investigated. It was found that all these factors have a considerable impact on the resulting column reliability.     

Intestinal transport of gentamicin with a novel, glycosteroid drug transport agent

PURPOSE: The objective was to investigate the ability of a glycosteroid (TC002) to increase the oral bioavailability of gentamicin. METHODS: Admixtures of gentamicin and TC002 were administered to the rat ileum by injection and to dogs by ileal or jejunal externalized ports, or PO. Bioavailability of gentamicin was determined by HPLC. 3H-TC002 was injected via externalized cannulas into rat ileum or jejunum, or PO and its distribution and elimination was determined. The metabolism of TC002 in rats was evaluated by solid phase extraction and HPLC analysis of plasma, urine and feces following oral or intestinal administration. RESULTS: The bioavailability of gentamicin was substantially increased in the presence of TC002 in both rats and dogs. The level of absorption was dependent on the concentration of TC002 and site of administration. Greatest absorption occurred following ileal orjejunal administration. TC002 was significantly more efficacious than sodium taurocholate, but similar in cytotoxicity. TC002 remained primarily in the GI tract following oral or intestinal administration and cleared rapidly from the body. It was only partly metabolized in the GI tract, but was rapidly and completely converted to its metabolite in plasma and urine. CONCLUSIONS: TC002 shows promise as a new drug transport agent for promoting intestinal absorption of polar molecules such as gentamicin.     

Characterization and quantification of folates produced by yeast strains isolated from kefir granules

For the first time to our knowledge, distribution and content of individual folate forms in kefir yeast strains were investigated. This was done using a validated method based on reversed-phase high performance liquid chromatography (HPLC) with fluorescence and diode array (DAD) detection. Eight kefir yeast strains, belonging to different Candida and Saccharomyces species, were isolated from Russian kefir granules. They were grown in synthetic media at standardized conditions before analysis. The average folate content for these yeast strains was 10,780±550 μg/100 g dry matter. In all yeast strains tested, the most abundant folate forms as percentages were 5-methyltetrahydrofolate (43–59%), and 5-formyltetrahydrofolate (23–38%), whereas tetrahydrafolate occurred in a lesser proportion (19–23%).     

Mitochondrial alterations and autofluorescent conversion of Candida albicans induced by histatins

The mechanism of the candidacidal activity of histatins 3 and 5 (Hst) is still a matter of debate. Previous studies have indicated that Hst induce cell permeabilization, generation of reactive oxygen species (ROS) by mitochondria, inhibition of the respiratory chain, and energy-dependent cytotoxic release of ATP. On the other hand, the multiplicity of effects and the apparent contrast between experimental data continue to render the mechanism of Hst-induced killing of C. albicans unclear. In this investigation, using fluorescent probes (the potential-sensitive mitochondrial probe tetramethylrhodamine methyl ester perchlorate, TMRM; the ROS-sensitive probe dihydrofluorescein diacetate, DHF; the membrane-impermeant probe, calcein) and autofluorescence data we observed that Hst induce ROS generation by mitochondria undergoing a high energy swelling condition, accompanied by oxidation of cytosolic NAD(P)H and mitochondrial flavoproteins. ROS generation and swelling, attributable to an inhibition of the respiratory chain and to impairment of the K/H-exchanger, were followed by mitochondrial depolarization. Mitochondrial changes were accompanied by massive calcein influx, indicative of cell permeabilization, and prominent alterations of the cell size, shape, and optical density. The loss of proliferative activity was correlated, on a single cell basis, to the acquisition of a lipofuscin-like autofluorescence.     

Impact of the Metal Adhesion Layer on the Radiation Power of Plasmonic Photoconductive Terahertz Sources

The use of plasmonic contact electrodes in a photoconductive terahertz source offers high optical-to-terahertz conversion efficiencies. The high efficiency is because plasmonic contact electrodes concentrate a large portion of the incident optical pump beam in close proximity to the contact electrodes. By reducing the average transport path length of the photo-generated carriers from the contact electrodes, a larger number of the photocarriers drift to the terahertz radiating elements of the photoconductive source within a sub-picosecond time scale. Therefore, higher terahertz radiation power levels are achieved compared to a similar photoconductive source without plasmonic contact electrodes. Au is a preferred metal for plasmonic contact electrodes because of the strong plasmonic enhancement factors it offers at near-infrared optical wavelengths. However, it requires an adhesion layer to stick well to most III–V semiconductor substrates used in photoconductive terahertz sources. In this paper, we analyze the impact of the Au adhesion layer on the performance of plasmonic photoconductive sources fabricated on a GaAs substrate. Our analysis suggests that Cr is the most promising adhesion layer for plasmonic contact electrodes. We show that the use of a Cr adhesion layer instead of Ti, which is used in previously demonstrated plasmonic photoconductive sources, offers up to an 80% enhancement in the generated terahertz powers. We report record-high terahertz power emissions of up to 6.7 mW from plasmonic photoconductive sources with Cr/Au contacts.     

Microwave‐induced enhancement of the dissolution rate of poorly water‐soluble tibolone from poly(ethylene glycol) solid dispersions

In this study, solid dispersions of poorly water‐soluble Tibolone in a poly(ethylene glycol) matrix were prepared with conventional melt mixing and microwave irradiation. The results of the assay content, LC–MS, and ¹H‐NMR indicated that microwave irradiation did not affect drug stability when a relatively low irradiation power (440 W) was used. Fourier transform infrared spectroscopy indicated that there were no hydrogen bonds formed between Tibolone and poly(ethylene glycol), and this affected the drug's crystallinity and its particle size distribution. The dissolution rate of the drug was slightly higher in the case of dispersions prepared by microwave irradiation. This enhancement of the drug dissolution rate was probably due to the lower size of the Tibolone particles in the dispersions prepared by microwave irradiation. The application of microwaves represents a promising alternative to conventional preparative methods of drug dispersions. The main advantage in comparison with conventional melt mixing is that solid dispersions can be prepared in much shorter times. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Sesamin Increases Alpha-Linolenic Acid Conversion to Docosahexaenoic Acid in Atlantic Salmon (<Emphasis Type="Italic">Salmo salar</Emphasis> L.) Hepatocytes: Role of Altered Gene Expression

In vitro cultivated Atlantic salmon (Salmo salar L.), hepatocytes were incubated without or with a mixture of sesamin and episesamin in order to test for possible effects on lipid metabolism. Sesamin/episesamin exposure (0.05 mM, final concentration) led to increased elongation and desaturation of ¹⁴C 18:3n-3 to docosahexaenoic acid (¹⁴C 22:6n-3, DHA, P < 0.01) and down regulated gene expression of Δ6 and Δ5 desaturases compared to control treatment. Sesamin/episesamin further increased the hepatocytes capacity for fatty acid β-oxidation of ¹⁴C 18:3n-3 (P < 0.01) to the ¹⁴C acid soluble products, acetate, malate and oxaloacetate, in agreement with an increased gene expression of carnitine palmitoyltransferase I. Also the gene expression of cluster of differentiation 36 was upregulated and the expression of scavenger receptor type B, peroxisome proliferator-activated receptors α and γ were downregulated. The amount of triacylglycerols secreted by the cells tended to be lower in the sesamin/episesamin incubated hepatocytes than the control cells. This study shows that sesamin has favourable effects on lipid metabolism leading to increased level of DHA, which may be of interest for aquaculture use.     

Styrene-butadiene polymer action on compressive and tensile strengths of cement mortars

This paper reports the results of an experimental investigation into the action of styrene-butadiene (SB) polymer on the mechanical properties of polymer cement mortars (PCM), comparing the results with the requirements specified in EN 1504-3 [Products and systems for the protection and repair of concrete structures—definitions, requirements, quality control and evaluation of conformity—part 3: structural and non-structural repair, CEN, 2005]. Setting times, shrinkage, elasticity modulus and the microstructure building in PCM are also characterised. Tests performed on PCM confirmed the beneficial action of polymers on tensile strength and, in particular, on flexural strength of cement mortars, whereas in compressive strength, a reduction, at earlier ages, was observed. It is considered that this mechanical behaviour results from the polymer action on the atrophy of hydrated Ca(OH)₂ crystals and on the reduction in the density of microcracks in the paste–aggregate interface, which leads to the noticeable improvement in flexural and tensile strengths. On the other hand, the smaller contribution of the beneficial action of the polymer on the compressive strength, together with the delay in cement hydration and with the increase in the closed porosity of PCM, are the main causes for the reduction in the compressive strength during the first months.