Isolation and antigenicity evaluation of &#946-lactoglobulin from buffalo milk

Buffalo &#946-lactoglobulin in phosphate buffer (0.02 M, pH6.8) was adsorbed on DEAE-Sepharose Fast Flow gel, and eluted with a linear gradient of NaCl (0-0.5 M) in 0.02 M phosphate buffer, pH 6.8. A furtherpurification was performed on Sephadex G-75 gel by loading a concentrated and dialyzed fraction of samples containing buffalo &#946-lactoglobulin from ion-exchange chromatography, and seperating at a flow rate of 0.15 ml/min in 0.02 M phosphate buffer, pH 6.8. The purity of the isolated buffalo &#946-lactoglobulin was above 90% in comparison to the standard bovine &#946-lactoglobulin by SDS-PAGE and IEF-PAGE. The antigencity of the buffalo &#946-lactoglobulin was evualuted by indirect ELISA, Westernblotting and inhibition ELISA with anti-buffalo and anti-bovine &#946-lactoglobulin rabbit serum. The results showed that buffalo &#946-lactoglobulin could be seperated and purified by anion-exchange chromatography combined with gel filtration chromatography, and with a well-preserved antigenicity

An incremental shifting vector approach for reliability-based design optimization

© 2015, Springer-Verlag Berlin Heidelberg. This paper proposes a decoupling algorithm for reliability-based design optimization (RBDO) with high performance in terms of efficiency and convergence, which provides an effective tool for reliability design of many complex structures. The algorithm proceeds by performing a shifting vector calculation and then solving a deterministic design optimization in each step, and eventually converges to the optimal solution. An incremental shifting strategy is proposed to ensure stable convergence in the iteration process. In each step, the shifting vector preserves the information from the previous step, and only an adjustment is made for it through a shifting vector increment. A computation method is given for the shifting vector increment, avoiding solving an optimization problem during the reliability analysis and thus greatly reducing the computational cost of the iteration process. Six numerical examples and two engineering applications are presented to validate the effectiveness of the method proposed in this paper

Composition of gut microbiota in infants in China and global comparison

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SUMO-2 promotes mRNA translation by enhancing interaction between eIF4E and eIF4G

Small ubiquitin-like modifier (SUMO) proteins regulate many important eukaryotic cellular processes through reversible covalent conjugation to target proteins. In addition to its many well-known biological consequences, like subcellular translocation of protein, subnuclear structure formation, and modulation of transcriptional activity, we show here that SUMO-2 also plays a role in mRNA translation. SUMO-2 promoted formation of the active eukaryotic initiation factor 4F (eIF4F) complex by enhancing interaction between Eukaryotic Initiation Factor 4E (eIF4E) and Eukaryotic Initiation Factor 4G (eIF4G), and induced translation of a subset of proteins, such as cyclinD1 and c-myc, which essential for cell proliferation and apoptosis. As expected, overexpression of SUMO-2 can partially cancel out the disrupting effect of 4EGI-1, a small molecule inhibitor of eIF4E/eIF4G interaction, on formation of the eIF4F complex, translation of the cap-dependent protein, cell proliferation and apoptosis. On the other hand, SUMO-2 knockdown via shRNA partially impaired cap-dependent translation and cell proliferation and promoted apoptosis. These results collectively suggest that SUMO-2 conjugation plays a crucial regulatory role in protein synthesis. Thus, this report might contribute to the basic understanding of mammalian protein translation and sheds some new light on the role of SUMO in this process. © 2014 Chen et al

Novel Tunable Fiber Optic Edge Filter Based on Modulating Chirp Rate of pi-Phase-Shifted Fiber Bragg Grating

We propose and experimentally demonstrate a novel tunable fiber optic edge filter based on modulating the chirp rate of a pi-phase-shifted fiber Bragg grating (FBG) operated in reflection mode. The phase shift induced notch in the reflection spectrum is utilized as the edge filter. The dependence of the pi-phase-shifted FBG's spectral response on the chirp rate has been numerically studied in detail and experimentally confirmed for the first time. The linear wavelength range of this edge filter can be tuned by changing the chirp rate of FBG. A fiber optic edge filter is further obtained experimentally and tested as a wavelength interrogator, which is in a good agreement with numerical results. The proposed edge filter has advantages of simple-structure, cost-effectiveness, high sensitivity, and flexible tunable, thus opening up some applications, especially as wavelength interrogator in small wavelength range

Population seroprevalence of antibody to influenza A(H7N9) virus, Guangzhou, China

BACKGROUND: Since the identification in early 2013 of severe disease caused by influenza A(H7N9) virus infection, there have been few attempts to characterize the full severity profile of human infections. Our objective was to estimate the number and severity of H7N9 infections in Guangzhou, using a serological study. METHODS: We collected residual sera from patients of all ages admitted to a hospital in the city of Guangzhou in southern China in 2013 and 2014. We screened the sera using a haemagglutination inhibition assay against a pseudovirus containing the H7 and N9 of A/Anhui/1/2013(H7N9), and samples with a screening titer ≥10 were further tested by standard hemagglutination-inhibition and virus neutralization assays for influenza A(H7N9). We used a statistical model to interpret the information on antibody titers in the residual sera, assuming that the residual sera provided a representative picture of A(H7N9) infections in the general population, accounting for potential cross-reactions. RESULTS: We collected a total of 5360 residual sera from December 2013 to April 2014 and from October 2014 to December 2014, and found two specimens that tested positive for H7N9 antibody at haemagglutination inhibition titer ≥40 and a neutralization titer ≥40. Based on this, we estimated that 64,000 (95 % credibility interval: 7300, 190,000) human infections with influenza A(H7N9) virus occurred in Guangzhou in early 2014, with an infection-fatality risk of 3.6 deaths (95 % credibility interval: 0.47, 15) per 10,000 infections. CONCLUSIONS: Our study suggested that the number of influenza A(H7N9) virus infections in Guangzhou substantially exceeded the number of laboratory-confirmed cases there, albeit with considerable imprecision. Our study was limited by the small number of positive specimens identified, and larger serologic studies would be valuable. Our analytic framework would be useful if larger serologic studies are done.published_or_final_versio

Ecosystem Carbon Stock Influenced by Plantation Practice: Implications for Planting Forests as a Measure of Climate Change Mitigation

Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha−1 in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age (<25 years vs. ≥25 years), stand types (broadleaved vs. coniferous and deciduous vs. evergreen), tree species origin (native vs. exotic) of plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation

A comparison of wear behaviour of heat resistant steel engine valves and TiAl engine valves

The increasingly demand for higher performance internal combustion engines (ICEs) has led to higher temperatures in the combustion chamber. As a result, TiAl valves have been investigated with a view to their use in a natural gas fuelled diesel ICE, taking advantage of their low density and good high temperature resistance. In this work, comparison bench tests for traditional steel valves and TiAl valves were carried out through the use of specially designed wear testing apparatus. Compared to the traditional valves made from heat resistant steel (X60, X85), the TiAl valves have 50 % lower mass, leading to a decrease in the impact seating forces during the engine operation. With the reduction of the inertia of engine valve movement, the dynamic characteristics of the engine valve train system can be optimized. Each contact pair of valve and seat insert was tested for 3 million impact cycles. Compared to the austenitic exhaust valves (X60) tested at 700 °C, the TiAl valve had better wear resistance and the wear loss decreased by 24.8 %. The predominant wear mechanism is considered to be a combination of oxidative wear and adhesive wear. However, for the intake valves tested at 400 °C, the wear loss of the TiAl valve was three times higher than the martensitic intake valves (X85). The predominant wear mechanism can be identified as abrasive wear and adhesive wear. It is therefore concluded that the TiAl exhaust valve is a potential solution for a natural gas fuelled diesel

Effect of moisture content on high strain rate compressibility and particle breakage in loose sand

Soil-filled gabion structures are widely used to protect against the effects of blast and fragmentation. It is known that moisture content significantly affects the capability of such structures, but the behaviour of partially-saturated soils is not well characterised at the strain rates and stresses experienced in these events. In particular, little data is available for loose soils, whose compaction behaviour can have a substantial impact on structural stability and ballistic performance. This paper describes the use of split Hopkinson pressure bar experiments to characterise the pre- and post-saturation compressibility of a loose quartz sand at moisture contents of up to 15.0%. In contrast to dense soils, increases in moisture content between 0.0% and 7.5% led to a decrease in the stiffness of the sand. Above 7.5% moisture content, specimens reached full saturation during the experiment: the additional water had no further effect on the pre-saturation stiffness, but post-saturation behaviour was dominated by the stiffness of the pore water. Full saturation occurred at lower dry densities as moisture content increased, leading to a decrease in particle breakage

CK8 phosphorylation induced by compressive loads underlies the downregulation of CK8 in human disc degeneration by activating protein kinase C

Cytokeratin 8 (CK8) is a member of the cytokeratins family with multiple functions on the basis of its unique structural hallmark. The aberrant expression of CK8 and its phosphorylation are pertinent with various diseases. We have previously shown that CK8 exists in normal human nucleus pulposus (NP) cells and decreases as the intervertebral disc degenerates. However, the underlying molecular regulatory machinery of CK8 in intervertebral disc degeneration (IDD) has not been clarified. Here, we collected NP samples from patients with idiopathic scoliosis as control and IDD as degenerate groups. We found that CK8 expression decreased in IDD with an increased phosphorylation in degenerate NP cells. Moreover, NP cells were cultured under different compressive load schemes for diverse time duration. We found that compressive loads resulted in phosphorylation and disassembly of CK8 in a time-dependent and degree-dependent manner in vitro. The activation of protein kinase C was a significant molecular factor contributing to this phenomenon. Taken together, this study is the first to address the molecular mechanisms of CK8 downregulation in NP cells. Importantly, our findings provide clues regarding a molecular link between compressive loads and CK8 alterations, which shed a novel light on the etiology of IDD.published_or_final_versio