Genotyping by dynamic heating of monolayered beads on a microheated surface

A miniaturized bead-based dynamic allele-specific hybridization (DASH) approach for single-nucleotide polymorphism analysis is presented. Chips with integrated heater and temperature sensors for open-surface DNA analysis were microfabricated. Microcontact printing using a poly(dimethylsiloxane) (PDMS) stamp was employed to create monolayers of immobilized beads on the surface of the chip. This chip allows fast, well-controllable temperature ramping. The temperature distribution was homogeneous over the entire heater area. All three possible variants of an SNP site of a synthesized oligonucleotide were accurately scored using the bead-based DASH approach. Our assay has a nonoptimized temperature ramping rate of 4 degrees C-6 degrees C/min compared to earlier reported values of 2 degrees C-3 degrees C/min, thereby reducing the total analysis time by a factor of 2. Reliable DASH measurement data from areas as small as 12 x 13 microm was achieved. Our bead-based DASH approach has enabled a dramatic volume reduction and is a step towards developing a cost-effective high-throughput DASH method on arrays of single beads.     

Potato peels as solid waste for the removal of heavy metal copper(II) from waste water/industrial effluent

A new sorbent potato peels, which are normally discarded as solid waste for removing toxic metal ion Cu(II) from water/industrial waste water have been studied. Potato peels charcoal (PPC) was investigated as an adsorbent of Cu(II) from aqueous solutions. Kinetic and isotherm studies were carried out by studying the effects of various parameters such as temperature, pH and solid liquid ratios. The optimum pH value for Cu(II) adsorption onto potato peels charcoal (PPC) was found to be 6.0. The thermodynamic parameters such as standard Gibb's free energy (Delta G degrees ), standard enthalpy (Delta H degrees ) and standard entropy (DeltaS degrees ) were evaluated by applying the Van't Hoff equation. The thermodynamics of Cu(II) adsorption onto PPC indicates its spontaneous and exothermic nature. The equilibrium data at different temperatures were analyzed by Langmuir and Freundlich isotherms.     

单个三维气泡的动力学特性研究

模拟了单个气泡在重力场作用下动态特性,假设流场为无粘、无旋且不可压的理想流体,采用三角形单元离散流场边界,并用边界积分法求解流场,用Mixed-Eulerian-Lagrangian方法模拟气泡的演化,并在必要的时候采用三维光顺方法对气泡表面及其速度势分布进行光顺,使计算程序更准确,更稳定.在分析过程中,将本文三维模型的计算结果与Rayleigh-Plesset气泡模型及试验数据进行对比分析,三维模型的计算值与精确解及实验数据吻合很好,表明本文方法及计算模型具有较高的精度,并通过对比改变不同物理参数时对气泡运动周期及射流速度的影响,得出一些规律性的曲线,旨在为相关的水下气泡动力学分析提供参考.     

Dimorphamides A – C,New Polyphenolic Amides from Atriplex dimorphostagia

Dimorphamides A–C ( 1 – 3 , resp.), three new polyphenolic amides, have been isolated from the BuOH‐soluble fraction of the whole plant of Atriplex dimorphostagia, along with two known compounds, thymidine and N‐[(E)‐feruloyl]tyramine. Their structures have been determined on the basis of spectral studies.     

Facile radical mediated synthesis of azetidin-2,3-diones: potential synthons for biologically active compounds

Abstract  

An operationally simple and efficient approach for the synthesis of azetidin-2,3-diones is described. The starting substrate 2-(2-bromobenzyloxy)ethanoyl chloride was treated with appropriate Schiff’s bases in triethylamine and dichloromethane to afford 3-(2-bromobenzyloxy)azetidin-2-ones. The synthesis of azetidin-2,3-diones was successfully achieved via radical mediated rearrangement of appropriately substituted 3-(2-bromobenzyloxy)azetidin-2-ones using n-tributyltin hydride and AIBN in refluxing dry benzene.     

Reflected Generalized Backward Doubly SDEs Driven by Lévy Processes and Applications

In this paper, we study reflected generalized backward doubly stochastic differential equations driven by Teugels martingales associated with Lévy process (RGBDSDELs in short) with one continuous barrier. Under uniformly Lipschitz coefficients, we prove an existence and uniqueness result by means of the penalization method and the fixed-point theorem. As an application, this study allows us to give a probabilistic representation for the solutions to a class of reflected stochastic partial differential integral equations (SPDIEs in short) with a nonlinear Neumann boundary condition.     

Development of a multianalyte method for the determination of anabolic hormones in bovine urine by isotope-dilution GC–MS/MS

A sensitive, specific and selective multianalyte GC–MS/MS method has been developed for the determination of 11 anabolic hormones in bovine urine. After adjusting the urine pH to 4.8, the samples were spiked with deuterated internal standards and submitted to enzymatic hydrolysis with β-glucuronidase/arylsulfatase. Hormones were eluted with methanol through a C18 solid phase cartridge and submitted to a liquid–liquid extraction. Analytes were derivatized by adding N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) with 1% trimethylchlorosilane and GC–MS data were obtained in the positive electron impact tandem mass mode. Under these conditions, no matrix effects were observed and limit of detection values were in the range of 0.005 ng/mL (diethylstilbestrol) to 0.38 ng/mL (17α-methyltestosterone and 17α-ethynylestradiol). Recoveries from 81% (α-zeranol) to 149% (17α-methyltestosterone) were found under the selected conditions. These results were better than those found using heptafluorobutyric anhydride (HFBA) as derivative reagent and those measured in full scan and selective ion monitoring modes.     

Structural and biochemical analyses reveal how ornithine acetyl transferase binds acidic and basic amino acid substrates

Structural and biochemical analyses reveal how ornithine acetyl-transferases catalyse the reversible transfer of an acetyl-group from a basic (ornithine) to an acidic (glutamate) amino acid by employing a common mechanism involving an acetyl-enzyme intermediate but using different side chain binding modes.