Adenosine A1 receptor activation mediates the developmental shift at layer 5 pyramidal cell synapses and is a determinant of mature synaptic strength

During the first postnatal month glutamatergic synapses between layer 5 pyramidal cells in the rodent neocortex switch from an immature state exhibiting high probability of neurotransmitter release, large unitary amplitude and synaptic depression to a mature state with decreased probability of release, smaller unitary amplitude and synaptic facilitation. Using paired recordings, we demonstrate that the developmental shift in release probability at synapses between rat somatosensory layer 5 thick-tufted pyramidal cells is due to a higher and more heterogeneous activation of presynaptic adenosine A1 receptors. Immature synapses under control conditions exhibited distributions of CV, failure rate and release probability that were almost coincident with the A1 receptor blocked condition; however, mature synapses under control conditions exhibited much broader distributions that spanned those of both the A1 receptor agonised and antagonised conditions. Immature and mature synapses expressed A1 receptors with no observable difference in functional efficacy and therefore the heterogeneous A1 receptor activation seen in the mature neocortex is due to increased adenosine concentrations that vary between synapses. Given the central role demonstrated for A1 receptor activation in determining synaptic amplitude and the statistics of transmission between mature layer 5 pyramidal cells, the emplacement of adenosine sources and sinks near the synaptic terminal could constitute a novel form of long-term synaptic plasticity

Visfatin reduces gap junction mediated cell-to-cell communication in proximal tubule-derived epithelial cells

Background/Aims: In the current study we examined if the adipocytokine, visfatin, alters connexin-mediated intercellular communication in proximal tubule-derived epithelial cells. Methods: The effects of visfatin (10-200ng/mL) on cell viability and cytotoxicity in HK2-cells were assessed by MTT, crystal violet and lactate dehydrogenase assays. Western blot analysis was used to confirm expression of Cx26, Cx40 and Cx43. The effect of visfatin (10-200ng/mL) on TGF-β1 secretion was confirmed by ELISA, and the effects of both TGF-β1 (2-10ng/mL) and visfatin (10-200ng/mL) on connexin expression were assessed by western blot. Functional intercellular communication was determined using transfer of Lucifer Yellow and paired-whole cell patch clamp electrophysiology. Results: In low glucose (5mM), visfatin (10-200ng/mL) did not affect membrane integrity, cytotoxicity or cell viability at 48hrs, but did evoke a concentration-dependent reduction in Cx26 and Cx43 expression. The expression of Cx40 was unaffected. At 48hrs, visfatin (10-200ng/mL) increased the secretion of TGF-β1 and the visfatin-evoked changes in connexin expression were mimicked by exogenous application of the pro-fibrotic cytokine (2-10ng/ml). Visfatin reduced dye transfer between coupled cells and decreased functional conductance, with levels falling by 63% as compared to control. Although input resistance was increased following visfatin treatment by 166%, the change was not significant as compared to control. The effects of visfatin on Cx-expression and cell-coupling were blocked in the presence of a TGF-β1 specific neutralizing antibody. Conclusions: The adipocytokine visfatin selectively evoked a non-toxic reduction in connexin expression in HK2-cells. The loss in gap-junction associated proteins was mirrored by a loss in functional conductance between coupled cells. Visfatin increased TGF-β secretion and the pattern of change for connexins expression was mimicked by exogenous application of TGF-β1. The effect of visfatin on Cx-expression and dye transfer were negated in the presence of a TGF-β1 neutralising antibody. These data suggest that visfatin reduces connexin-mediated intercellular communication in proximal tubule-derived epithelial cells via a TGF-β dependent pathway. © 2013 S. Karger AG, Base

Generalized analysis of quasi-steady-state and transient decay open circuit voltage measurements

The current–voltage characteristics of solar cells and photodiodes can be determined by measuring the open-circuit voltage as a function of a slowly varying light intensity. This article presents a detailed theoretical analysis and interpretation of such quasi-steady-state Vocmeasurements(QssVoc). The ability of this analysis to accurately obtain the true steady-state device characteristics even in the case of high lifetime, high resistivitysilicon devices is demonstrated experimentally. The QssVoc technique can be used to determine the minority carrier lifetime, and the new generalized analysis is required to do this accurately. An important outcome is that solar cell and diode device characteristics can be obtained from measurements of either the photoconductance or the open-circuit voltage, even using transient techniques.This work has been funded by the Australian Research Council. The authors also thank S. Glunz and S. Rein from the Fraunhofer Institute of Solar Energy Systems, for the use of the solar cell used in Fig. 5

Bioenergy Co-products as Swine Feed Ingredients: Combining DDGS and Glycerol

Bioenergy production generates two major coproducts—distillers dried grains with solubles (DDGS) from ethanol plants and crude glycerol from biodiesel plants. We need to evaluate whether these co-products, DDGS and glycerol, can be fed in combination to partially meet the feed energy needs of growing pigs. If successful, the diet with 25% DDGS and 10% glycerol has the potential to reduce corn feeding to market pigs by 40+%. The objective was to evaluate feeding crude glycerol and DDGS in combination to market swine. At the processing plant, a fat sample was taken from the jowl of each pig. The fat sample was analyzed for fatty acids. Pig performance and carcass traits did not differ between diets. Fatty acid composition showed differences based on the dietary treatments. Saturated fatty acids were highest for diets with the most corn and least DDGS – the corn-soy and 10% glycerol diets (P \u3c 0.01). Mono unsaturated fatty acids were highest for the 10% glycerol diet and decreased as DDGS was added with the lowest value for the 25% DDGS diet (P \u3c 0.01). Poly-unsaturated fats were lowest for the corn-soy and 10% glycerol diets and highest for the 25% DDGS diets (P \u3c 0.001). The results of this study show that pig performance was not affected by the addition of DDGS and crude glycerol. The amount of corn fed can be reduced by the addition of DDGS and glycerol. DDGS increases the unsaturated fatty acids in pork fat. Crude glycerol addition partially offsets the DDGS fatty acid effect by reducing polyunsaturated fatty acid content

Feeding Bioenergy Coproducts to Swine: Crude Glycerol

Biodiesel can be produced from a variety of fats and oils. Soybean oil is the primary feedstock in Iowa. In general, soybean oil is mixed with an alcohol (usually methanol) and a catalyst. The action of the alcohol and catalyst cause the oil (triacylglyceride) molecules to be broken down into methyl esters (biodiesel) and crude glycerol. Crude glycerol is the principal co-product of biodiesel production. For every gallon of biodiesel produced, 0.7 pounds of crude glycerol are co-generated. Biodiesel sales in the United States have increased rapidly since 1999 and annual production capacity in the U.S. is nearly 1.4 billion gallons. Iowa has 11 operating plants with 3 additional plants expected to be operational by December 2007. Production capacity in Iowa for biodiesel is 318.5 million gallons. Approximately 110,000 tons of crude glycerol could be generated annually by the biodiesel plants within Iowa

Growth and Performance of Nursery Pigs Fed Crude Glycerol

The growth and performance of 96 nursery pigs fed crude glycerol was evaluated in a 33 d trial. Pigs were weaned at 21 d of age and had an average start weight of 7.9±1.2 kg (17.4±2.6 lb). Pigs were provided ad libitum access to corn soybean diets containing three levels of crude glycerol, 0, 5, or 10%. Diets were formulated to be ioscaloric and isolysinic. There was no difference in pig performance based on dietary treatment. Crude glycerol can be fed to young pigs as an energy source without growth or performance effects

Millisecond minority carrier lifetimes in n-type multicrystalline silicon

Exceptionally high minority carrier lifetimes have been measured in n-type multicrystalline silicon (mc-Si) grown by directional solidification and subjected to phosphorus gettering. The highest effective lifetimes, up to 1.6 ms averaged over several grains and 2.8 ms within some of them, were measured for relatively lowly doped, 2–3 Ωcm, wafers. The lifetime was found to decrease for lower resistivities, still reaching 500 μs for 0.9 Ωcm and 100 μs for 0.36 Ωcm. Several important findings are reported here: (i) achievement of carrier lifetimes in the millisecond range for mc-Si, (ii) effectiveness of phosphorus gettering in n-type mc-Si, and (iii) demonstration of good stability under illumination for n-type mc-Si.This work has been partially supported by the Australian Research Council

Growth Performance of Growing Pigs Fed Crude Glycerol-Supplemented Diets

Growth performance of growing pigs fed crude glycerol was determined in a 138-d feeding trial. Crude glycerol utilized in the trial contained 84.51% glycerol, 11.95% water, 2.91% sodium chloride, and 0.32% methanol. Eight days post-weaning, 96 pigs (48 barrows, 48 gilts) with an average BW of 7.9 ± 0.4 kg were allotted to 24 pens (4 pigs/pen), with gender and pen weight balanced at the start of the experiment. Dietary regimes were randomly assigned to each pen. Dietary treatments were 0, 5, and 10% crude glycerol inclusion in corn-soybean meal based diets. Diets were offered ad libitum in meal form and formulated to be equal in metabolizable energy (ME), sodium, chloride, and Lys, with other amino acids (AA) balanced on an ideal AA basis. Every two weeks, pigs and feeders were weighed and G:F calculated. Pig growth, feed intake, and G:F were not affected by dietary treatment. Crude glycerol is a viable source of dietary energy that is well utilized by pigs. Inclusion of crude glycerol in pig diets may be determined by relative availability and price of other dietary energy sources