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BackgroundHeat stress has resulted in great losses in poultry production. To address this issue, we systematically analyzed chicken hypothalamus transcriptome responses to thermal stress using a 44 k chicken Agilent microarray,MethodsHypothalamus samples were collected from a control group reared at 25°C, a heat-stress group treated at 34°C for 24 h, and a temperature-recovery group reared at 25°C for 24 h following a heat-stress treatment. We compared the expression profiles between each pair of the three groups using microarray data.ResultsA total of 1,967 probe sets were found to be differentially expressed in the three comparisons with P < 0.05 and a fold change (FC) higher than 1.5, and the genes were mainly involved in self-regulation and compensation required to maintain homeostasis. Consistent expression results were found for 11 selected genes by quantitative real-time PCR. Thirty-eight interesting differential expression genes were found from GO term annotation and those genes were related to meat quality, growth, and crucial enzymes. Using these genes for genetic network analysis, we obtained three genetic networks. Moreover, the transcripts of heat-shock protein, including Hsp 40 and Hsp 90, were significantly altered in response to thermal stress.ConclusionsThis study provides a broader understanding of molecular mechanisms underlying stress response in chickens and discovery of novel genes that are regulated in a specific thermal-stress manner.Electronic supplementary materialThe online version of this article (doi:10.1186/s40104-015-0003-6) contains supplementary material, which is available to authorized users.

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This study presents a study on non-linear accumulative modelling for power module lifetime estimation in nonaccelerated operation. The model focuses on solder fatigue based on monitoring the internal thermal resistance of the module. Initially, the relatively small junction temperature variation (ΔT j) cycles contribute little to the lifetime consumption, but with an initial damage the effect becomes noticeable. The original Coffin-Manson accumulation approach is extended for complex mission profiles. The proposed non-linear accumulation model has three aspects: a Coffin-Manson relationship is first established; the thermal resistance degradation is then used to quantify damage accumulation; the effects of the average junction temperature (T jmean) and ΔT j on the rate of degradation are finally included through the parameters of the non-linear accumulation model which also depends on the effect of the present condition of the module. Experiments demonstrate the phenomena and verify the proposed model.

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