Absorption of Di- and triglycerides by intestinal slices in vitro

The uptake by hamster intestinal rings of labeled 1,3-diolein and triolein in bile salt emulsions was studied. About 6% of triolein was taken up from emulsions containing glycerides and fatty acid in 6 mM sodium taurodeoxycholate. Lesser uptake was noted when triolein was emulsified with lecithin, cholesterol and bile salt; lowest uptake (3%) was observed from triolein-lecithincholesterol emulsions prepared without bile salt. Absorption of 1,3-diolein from bile salt emulsion was greater and acylation to triglyceride was observed. Diglycerides and triglycerides in small quantity may be absorbed intact from a micellar phase.     

Effects of plasma treatment on mechanical properties of rubber/cellulose fibre composites

Natural rubber materials reinforced with cellulose fibres have been studied with respect to crosslink density, tensile strength and stress relaxation. The fibres have been grafted with butadiene or divinylbenzene by plasma treatment. Chemiluminescence analysis was used to indicate the grafting on the surface of the cellulose fibres and also to estimate the effect of the plasma on the cellulose fibres. The results indicate the possibility of obtaining a surface layer on the fibres, which is a conceivable way of improving the mechanical properties of rubber composites.     

Radiation crosslinking of polyethylene with electron beam at different temperatures

The effect of temperature over the range ?196 to 150°C on the crosslinking of polyethylenes irradiated by electron beam has been investigated on the basis of gel content determination and Fourier transform infra-red (FTIR) spectroscopy. The crosslinking efficiency increases significantly with increasing irradiation does and at elevated irradiation temperature. The crosslinking rates of high density polyethylene (HDPE) and low density polyethylene (LDPE) samples above the melting point (T_M) are much higher than those below T_m. The FTIR data give positive evidence: (i) that trans-vinylene double bonds in cross linked HDPE and LDPE samples increase with increasing irradiation dose temperature (ii) that vinyl double bonds in HDPE decrease rapidly with increasing irradiation dose and temperature, and (iii) vinylidene groups in LDPE decrease slowly with increasing temperature at the lower dose and are almost independent of the irradiation temperature at above room temperature and the higher dose of more than 100 kGy. Gas bubbles are observed in LDPE samples irradiated at 100 and 150°C with high dose (200 to 250 kGy). The size of the bubbles increases gradually at high temperatures.     

Mass spectrometric determination of positions of double bonds in polyunsaturated fatty acid pyrrolidides

Low resolution mass spectra of pyrrolidides of isomeric octadecadienoic acids and other polyunsaturated straight chain fatty acids are presented and discussed. The spectra of the pyrrolidides contain mainly ions from the polar part of the molecule and give spectra that are specific for each isomer. The interpretation follows, in most cases, the rule developed for monounsaturated fatty acid pyrrolidides.     

The effect of prandtl number on conjugate heat transfer from rectangular fins

The problem of conjugate heat transfer from rectangular fins is treated numerically. Results are provided for the three Prandtl numbers (three fluids) 0.021, 0.7 and 5.0 and convection - conduction parameters meters in the range of 0 ≤ √Re k_fL/k_sb = CCP ≤ 5. The results indicated great effects of both CCP and Pr. Comparisons with the simple conventional fin theory show that concerning the fin efficiency, the simple theory yields acceptable results while the temperature variation and local heat flux distributions are not correctly predicted.     

Effects of dietary phenolic compounds on tocopherol, cholesterol, and fatty acids in rats

The effects of the phenolic compounds butylated hydroxytoluene (BHT), sesamin (S), curcumin (CU), and ferulic acid (FA) on plasma, liver, and lung concentrations of α- and γ-tocopherols (T), on plasma and liver cholesterol, and on the fatty acid composition of liver lipids were studied in male Sprague-Dawley rats. Test compounds were given to rats ad libitum for 4 wk at 4 g/kg diet, in a diet low but adequate in vitamin E (36 mg/kg of γ-T and 25 mg/kg of α-T) and containing 2 g/kg of cholesterol. BHT significantly reduced feed intake (P<0.05) and body weight and increased feed conversion ratio; S and BHT caused a significant enlargement of the liver (P<0.001), whereas CU and FA did not affect any of these parameters. The amount of liver lipids was significantly lowered by BHT (P<0.01) while the other substances reduced liver lipid concentrations but not significantly. Regarding effects on tocopherol levels, (i) feeding of BHT resulted in a significant elevation (P<0.001) of α-T in plasma, liver, and lung, while γ-T values remained unchanged; (ii) rats provided with the S diet had substantially higher γ-T levels (P<0.001) in plasma, liver, and lung, whereas α-T levels were not affected; (iii) administration of CU raised the concentration of α-T in the lung (P<0.01) but did not affect the plasma or liver values of any of the tocopherols; and (iv) FA had no effect on the levels of either homolog in the plasma, liver, or lung. The level of an unknown substance in the liver was significantly reduced by dietary BHT (P<0.001). BHT was the only compound that tended to increase total cholesterol (TC) in plasma, due to an elevation of cholesterol in the very low density lipoprotein + low density lipoprotein (VLDL+LDL) fraction. S and FA tended to lower plasma total and VLDL+LDL cholesterol concentrations, but the effect for CU was statistically significant (P<0.05). FA increased plasma high density lipoprotein cholesterol while the other compounds reduced it numerially, but not significantly. BHT, CU, and S reduced cholesterol levels in the liver TC (P<0.001) and percentages of TC in liver lipids (P<0.05). With regard to the fatty acid composition of liver lipids, S increased the n-6/n-3 and the 18∶3/20∶5 polyunsaturated fatty acids (PUFA) ratios, and BHT lowered total monounsaturated fatty acids and increased total PUFA (n−6+n−3). The effects of CU and FA on fatty acids were not highly significant. These results suggest some in vivo interactions between these phenolic compounds and tocopherols that may increase the bioavailability of vitamin E and decrease cholesterol in rats.     

Housing Indicators: A tool for research?

Conclusions The Housing Indicators Program will generate a large data set, involving a number of countries where reliable data has not yet been available. It will be most useful for the analysis of housing markets, especially in a comparative perspective. My critical comments concerned on the relevance and reliability of the indicators to assess the housing situation in countries with different housing objectives. I have also commented on possible missing indicators and warned against an uncritical use of the outcomes of an indicator study. I do believe, however, that if the indicators are used in a responsible way, the program has the potential of becoming a useful tool in the evaluation and implementation of housing policy. Finally, the Indicators Program will help to put housing policy on the political agenda-which is where it belongs.     

Oxygen uptake of bottom sediments studied in situ and in the laboratory

Oxygen uptake by soft bottom sediments was measured in situ with an oxygen electrode in a bell jar. Values in the range 0·3-3·0 g O₂ m⁻² d⁻¹ were obtained at 19 localities in fresh and brackish water. Comparative measurements were made in the laboratory on sediment cores. These gave consistently lower values than the in situ measurements. Laboratory experiments showed that the oxygen uptake depended on the oxygen concentration and that the temperature coefficient decreased with increasing temperature. There was no simple correlation between oxygen uptake and content organic matter in sediments.     

Nitrogen form affects yield and taste of tomatoes

Different nitrogen forms in organic or mineral fertilizers affect yield, quality and taste of tomatoes. Tomato plants were grown in a greenhouse for 10 weeks and fertilized with two different organic fertilizers (manure or grass and clover mulch) or with three different mineral nutrient solutions (NO₃^?:NH₄⁺) ratios 4:1 or 1:4). In an attempt to mimic the nutrient supply of the organic production systems, mineral fertilizers with ammonium as the dominating N‐source were combined with two chloride levels. Total nitrogen supply was 650 mg N plant^?1 week^?1 in all treatments. There was no difference in the yield of red tomatoes between the treatments (mean 1.95 kg FW plant^?1). However, the yield of green tomatoes at the final harvest was significantly higher in the mineral nutrient treatments (mean 1.37 kg FW plant^?1) compared with the organic treatments (mean 0.88 kg FW plant^?1). Plant biomass was higher for the mineral nutrient treatments (mean 1.05 kg FW plant^?1) compared with the organic treatments (0.89 kg and 0.72 kg FW plant^?1 in the manure and the grass and clover mulch treatments, respectively). Significantly higher scores were achieved for sweetness, acidity, flavour and acceptance for the tomatoes grown with the organic or the ammonium‐dominated treatments compared with the tomatoes grown with the nitrate dominated nutrient solution. It is suggested that ammonium is an equivalent nitrogen source for tomato plants compared with nitrate and that, when tomato plants are supplied with reduced nitrogen forms such as ammonium or organic nitrogen, an improved tomato fruit taste can be observed. Copyright © 2005 Society of Chemical Industry     

PID Effect of c-Si Modules: Study of Degradation and Recovery to More Closely Mimic Field Behavior

Recent research demonstrates several failure modes of photovoltaic modules operating under high electric potentials. In crystalline-silicon modules, the predominant failure mode is potential-induced degradation (PID), causing dramatic power losses in systems under high voltage and critical polarity. Environmental conditions highly influence the degradation behavior. The ability to reproduce field observation in the laboratory is challenging and not all stressors can be checked simultaneously. PID and its root cause are not fully understood, but we know several mechanisms are working simultaneously and at varying rates. The main mechanisms are degradation, characterized by ion diffusion and cell shunting, and recovery, driven by temperature, voltage, and potential. Most studies have focused on simulating module degradation using a constant set of parameters. However, field exposure to high voltage is variable, measured by the hour. In 2012, Nagel presented a module stability test with varying environmental conditions, notably temperature. To investigate PID remedies, this research develops a testing procedure that reproduces field observations while understanding that some modules do not degrade in real PV installations under high potentials. Conductive foil is applied to the front side of the module and voltage cycling is introduced to examine potential-induced degradation and potential-induced recovery behavior. The relationship between the two defines a PID stability criterion. Results show general PID sensitivity and suitable remedies for PID affected systems. PID recovery and protection solutions include applying recovery potential at night, and potential shifting, which regulates potential for the module string. This paper explores possible degradation mechanisms, recovery of module output power and PID stability criteria.