741 research outputs found
Molecular characters and recombinant expression of the carboxylesterase gene of the meadow moth Loxostege sticticalis L. (Lepidoptera: Pyralidae)
Insect carboxylesterases are enzymes that catalyze the hydrolysis of ester and amide moieties, which play important roles in insecticide resistance, specifically allelochemical tolerance and developmental regulation. We obtained the cDNA encoding carboxylesterase gene of Loxostege sticticalis (LstiCarE) by a cDNA library screen. The full cDNA of LstiCarE is 1,980 bp in length, containing an open reading frame (ORF) of 1,875 bp, which encodes a preprotein of 625 amino acid residues. The LstiCarE contains the catalytic triad (Ser-His-Glu), the pentapeptide GxSxG motif and GxxHxxD/E motif, which are typical characteristic of esterases. The GxSxG and GxxHxxD/E motifs of LstiCarE are modified as GCSAG and GxxHxxQ, respectively. The 3-D model structure of LstiCarE showed that Ser197, His440 and Glu321 are aggregated together, which form the catalytic triad. The recombinant LstiCarE were successfully expressed in BL21 cells using recombinant plasmid DNA, and showed high carboxylesterase activity. However, the biochemical and physiological functions of carboxylesterase gene in L. sticticalis requires further investigation.Key words: Carboxylesterase gene, Loxostege sticticalis, recombinant expression
Prediction of the functional class of metal-binding proteins from sequence derived physicochemical properties by support vector machine approach
Metal-binding proteins play important roles in structural stability, signaling, regulation, transport, immune response, metabolism control, and metal homeostasis. Because of their functional and sequence diversity, it is desirable to explore additional methods for predicting metal-binding proteins irrespective of sequence similarity. This work explores support vector machines (SVM) as such a method. SVM prediction systems were developed by using 53,333 metal-binding and 147,347 non-metal-binding proteins, and evaluated by an independent set of 31,448 metal-binding and 79,051 non-metal-binding proteins. The computed prediction accuracy is 86.3%, 81.6%, 83.5%, 94.0%, 81.2%, 85.4%, 77.6%, 90.4%, 90.9%, 74.9% and 78.1% for calcium-binding, cobalt-binding, copper-binding, iron-binding, magnesium-binding, manganese-binding, nickel-binding, potassium-binding, sodium-binding, zinc-binding, and all metal-binding proteins respectively. The accuracy for the non-member proteins of each class is 88.2%, 99.9%, 98.1%, 91.4%, 87.9%, 94.5%, 99.2%, 99.9%, 99.9%, 98.0%, and 88.0% respectively. Comparable accuracies were obtained by using a different SVM kernel function. Our method predicts 67% of the 87 metal-binding proteins non-homologous to any protein in the Swissprot database and 85.3% of the 333 proteins of known metal-binding domains as metal-binding. These suggest the usefulness of SVM for facilitating the prediction of metal-binding proteins. Our software can be accessed at the SVMProt server
Technology Development Through Pooling ARV Drug Patents: A Vision from China
Unaffordable prices still bar the end-users in China from accessing ARV drugs. Patent protection of ARV drugs has dramatically limited the availability of these lifesaving drugs to AIDS patients in China
Chemical characterization of PM2.5 from a southern coastal city of China:applications of modeling and chemical tracers in demonstrationof regional transport
An intensive sampling campaign of airborne fine particles (PM2.5) was conducted at Sanya, a coastal city in Southern China, from January to February 2012. Chemical analyses and mass reconstruction were used identify potential pollution sources and investigate atmospheric reaction mechanisms. A thermodynamic model indicated that low ammonia and high relative humidity caused the aerosols be acidic and that drove heterogeneous reactions which led to the formation of secondary inorganic aerosol. Relationships among neutralization ratios, free acidity, and air-mass trajectories suggest that the atmosphere at Sanya was impacted by both local and regional emissions. Three major transport pathways were identified, and flow from the northeast (from South China) typically brought the most polluted air to Sanya. A case study confirmed strong impact from South China (e.g., Pearl River Delta region) (contributed 76.8% to EC, and then this result can be extended to primary pollutants) when the northeast winds were dominant. The Weather Research Forecasting Black carbon model and trace organic markers were used to apportion local pollution versus regional contributions. Results of the study offer new insights into the atmospheric conditions and air pollution at this coastal city
Wind-thermal power system dispatch using MLSAD model and GSOICLW algorithm
The decision support model of mean-lower semi-absolute deviation (MLSAD) and the optimization algorithm of group search optimizer with intraspecific competition and lévy walk (GSOICLW) are presented to solve wind-thermal power system dispatch. MLSAD model takes the profit and downside risk into account simultaneously brought by uncertain wind power. Using a risk tolerance parameter, the model can be converted to a single-optimization problem, which is solved by an improved optimization algorithm, GSOICLW. Afterwards, both the model and the algorithm are tested on a modified IEEE 30-bus power system. Simulation results demonstrate that the MLSAD model can well solve wind-thermal power system dispatch. The study also verifies GSOICLW obtains better convergent dispatching solutions, in comparison with other evolutionary algorithms, such as group search optimizer and particle swarm optimizer.NRF (Natl Research Foundation, S’pore)EDB (Economic Devt. Board, S’pore)Accepted versio
Preliminary study on the utilization of Ca2+ and HCO3 − in karst water by different sources of Chlorella vulgaris
This article aims to present a picture of how a university discipline has been created in Lithuania, given the background of changes caused by the Lithuania’s emancipation from the Soviet Union. The theoretical frame of reference is provided by a modified model of Bronfenbrenners developmental ecology. Data collection has primarily been in the form of interviews with university staff from Lithuanian institutions for higher education. In addition to the interviews, literature lists, course schedules and other key documents have been collected and analysed. The analysis focuses on individual’s conceptualisation of three main areas. The study demonstrates how the creation of management and economics as a university discipline in Lithuania has been formed by a combination of political/ideological, economic, institutional and individual factors. One of the study’s main contributions is to highlight the significance of the concept of academic freedom and to focus on the paradox, where constraint under the old system is replaced by another form of constraint. In this case, where the rigidity of the old Soviet doctrine is replaced by a new freedom; but instead of being given greater opportunities to influence and change the subject, the academic staff are forced into a position where, once again they are subjugated to the influences of international sources
Controlled Growth of Carbon Spheres Through the Mg-Reduction Route
Hollow spheres, hollow capsules and solid spheres of carbon were selectively synthesized by Mg-reduction of hexachlorobutadiene at appropriate reaction conditions. X-ray powder diffraction and Raman spectra reveal that the as-prepared materials have a well-ordered structure. A possible formation mechanism has been proposed
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Three-Dimensional Graphene Nano-Networks with High Quality and Mass Production Capability via Precursor-Assisted Chemical Vapor Deposition
We report a novel approach to synthesize chemical vapor deposition-grown three-dimensional graphene nano-networks (3D-GNs) that can be mass produced with large-area coverage. Annealing of a PVA/iron precursor under a hydrogen environment, infiltrated into 3D-assembled-colloidal silicas reduces iron ions and generates few-layer graphene by precipitation of carbon on the iron surface. The 3D-GN can be grown on any electronic device-compatible substrate, such as Al2O3, Si, GaN, or Quartz. The conductivity and surface area of a 3D-GN are 52 S/cm and 1,025 m(2)/g, respectively, which are much better than the previously reported values. Furthermore, electrochemical double-layer capacitors based on the 3D-GN have superior supercapacitor performance with a specific capacitance of 245 F/g and 96.5% retention after 6,000 cycles due to the outstanding conductivity and large surface area. The excellent performance of the 3D-GN as an electrode for supercapacitors suggests the great potential of interconnected graphene networks in nano-electronic devices and energy-related materials.open15
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