Primer Extension Reaction Assays for Incorporation of Deoxynucleotide Analogue into DNA

Incorporation of deoxynucleotide analogues into DNA is important for the expansion of DNA functions. Primer extension reactions are commonly used for the assay of such reaction events. However, current assay protocols generally rely on radiolabeling, fluorescence reporter labeling, or removal of specific deoxynucleotide triphosphate in the reaction mixture. Herein we report on the design of two novel assay protocols that utilize a dideoxynucleotide‐terminated template strand and a phosphorothiolate‐modified deoxynucleotide‐terminated template strand. We designed and synthesized a deoxyuridine triphosphate analogue (dU*TP) containing 2‐bromoisobutyryl group and demonstrated that it could be well recognized by ?29DNA polymerase, E. coli DNA polymerase I Klenow Fragment, Bst DNA polymerase Large Fragment, and E. coli DNA polymerase I Klenow Fragment (exo⁽), which translated to effective incorporation of dU*TP into DNA. dU*TP was also successfully incorporated into extremely long single‐stranded DNA at high‐density using ?29 DNA polymerase by rolling circle amplification.     

An analysis on the efficiency of Euler's method for computing the matrix pth root

It is shown that the matrix sequence generated by Euler's method starting from the identity matrix converges to the principal pth root of a square matrix, if all the eigenvalues of the matrix are in a region including the one for Newton's method given by Guo in 2010. The convergence is cubic if the matrix is invertible. A modification version of Euler's method using the Schur decomposition is developed. Numerical experiments show that the modified algorithm has the overall good numerical behavior.     

Analysis of methylene blue and its metabolites in blood by capillary electrophoresis/electrospray ionization mass spectrometry

A method for the determination of methylene blue (MB) and its metabolites (azure A, azure B and azure C) in rat blood by CE-electrospray ionization mass spectrometry (CE-ESI-MS) was developed in this paper. Different analytical parameters were investigated in detail such as pH and concentration of separation buffer, and ESI-MS instrumental parameters. Under the optimum conditions, MB and its metabolites were separated and detected in 27.3 min. LODs (defined as S/N=3) of this method were 0.22, 0.25, 0.10 and 0.30 μg/mL for MB, azure A, azure B and azure C, respectively. To get a satisfactory extraction efficiency of MB and its metabolites in rat blood, different extraction solutions were studied. By using this method, MB and its metabolites (azure A, azure B and azure C) were successfully analyzed in rat blood samples.     

波纹结构迎爆面泡沫金属对甲烷-空气混合气体爆炸能量的吸收特性

为进一步探究气体爆炸荷载下异构迎爆面泡沫金属的吸能特性,在前期开展锯齿结构迎爆面材料吸能特性实验的基础上,以3种波纹结构迎爆面（凸面型、凹面型和凹凸连续型）泡沫金属材料为研究对象,利用自主搭建的气体爆炸管网实验平台,开展了该泡沫金属材料在甲烷-空气混合气体爆炸荷载下的吸能特性测定实验。采用不同波纹结构迎爆面阻隔爆材料,测定了管道内爆炸冲击波超压、火焰传播速度和火焰温度等随时间和空间的变化,分析了不同波纹结构迎爆面阻隔爆材料的吸能效果。结果表明：(1)迎爆面为波纹结构的泡沫金属材料对爆炸超压的衰减效果优于迎爆面为锯齿结构的泡沫金属材料和迎爆面为平面结构的泡沫金属材料,且迎爆面为凸面型波纹结构和凹凸连续型波纹结构的泡沫金属材料对超压衰减的速率高于迎爆面为锯齿结构和凹面型波纹结构的泡沫金属材料;迎爆面为锯齿结构的泡沫金属材料对火焰传播速度的衰减略强于迎爆面为波纹结构和平面结构的泡沫金属材料;迎爆面为波纹结构的泡沫金属材料对火焰温度的衰减效果优于迎爆面为锯齿结构及平面结构的泡沫金属材料。(2)在本文实验条件下,3种波纹结构（凸面型、凹面型和凹凸连续型）迎爆面泡沫金属材料的熄爆参数分别为5.338、4.340和6.090 MPa·℃,低于锯齿结构迎爆面材料的熄爆参数17.680 MPa·℃,且远低于熄爆参数安全值390 MPa·℃,波纹结构迎爆面材料具有良好的防护效果。(3)这3种迎爆面为波纹结构的泡沫金属材料均具有良好的吸能特性,均优于迎爆面为锯齿形结构的泡沫金属材料,且明显优于迎爆面为平面结构的泡沫金属材料。

     

Multiple periodic solutions of a delayed stage-structured predator–prey model with non-monotone functional responses

A delayed stage-structured predator–prey model with non-monotone functional responses is proposed. It is assumed that immature individuals and mature individuals of the predator are divided by a fixed age, and that immature predators do not have the ability to attack prey. Some new and interesting sufficient conditions are obtained for the global existence of multiple positive periodic solutions of the stage-structured predator–prey model. Our method is based on Mawhin’s coincidence degree and novel estimation techniques for the a priori bounds of unknown solutions to Lx = λNx. An example is given to illustrate the feasibility of our main result.     

A proof of Selberg's orthogonality for automorphic L-functions

Let π and π′ be automorphic irreducible cuspidal representations of GL_m(Q_A) and GL_m′(Q_A), respectively. Assume that π and π′ are unitary and at least one of them is self-contragredient. In this article we will give an unconditional proof of an orthogonality for π and π′, weighted by the von Mangoldt function Λ(n) and 1−n/x. We then remove the weighting factor 1−n/x and prove the Selberg orthogonality conjecture for automorphic L-functions L(s,π) and L(s,π′), unconditionally for m≤4 and m′≤4, and under the Hypothesis H of Rudnick and Sarnak [20] in other cases. This proof of Selberg's orthogonality removes such an assumption in the computation of superposition distribution of normalized nontrivial zeros of distinct automorphic L-functions by Liu and Ye [12].     

水资源持续利用的多目标决策模型的建立

可持续发展战略的实施,资源的可持续利用是关键.针对日趋短缺的淡水资源,根据多目标决策理论,以同时追求经济、环境、社会效益为主要目标提出了其可持续利用的多目标决策模型,并举例说明了模型的应用,旨在为决策者提供淡水利用规划的依据.     

Solubility and Thermodynamic Properties of (1R,2R)-(+)-1,2-Diaminocyclohexane L-Tartrate in Methanol (Ethanol or 2-Propanol) + Water Binary Solvents at Various Temperatures

Russian Journal of Physical Chemistry A - The solubility of (1R,2R)-(+)-1,2-diaminocyclohexane L-tartrate (DHT) in methanol + water, ethanol + water, and 2-propanol + water mixed solvents were...     

A "teardown" method to create large mesotunnels on the pore walls of ordered mesoporous silica

A "teardown" method to create large mesotunnels (approximately 9 nm) on the pore walls of ordered mesoporous silicas is demonstrated by digesting the organic constituents from polymer-silicate nanocomposites. The ordered mesostructured polymer-silicate composites were first obtained via the evaporation-induced triconstituent co-assembly method by using a low-molecular-weight phenolic resin (resols) as an organic precursor; prehydrolyzed TEOS as an inorganic precursor, and triblock copolymer F127 as a template. All of organic components including F127 and phenolic resins are removed by the microwave digestion (MWD) method from mesostructured polymer-silica composites. While the removal of triblock copolymer F127 generates main pore channels, the phenolic resins can also be torn down from the pore walls, yielding mesotunnels between the channels. The resulting silica products exhibit ordered 2-D hexagonal mesostructure, large pore volume (up to 1.92 cm(3)/g), and very large pore size (up to 22.9 nm), which is even larger than their mesostructural cell parameter (14.2 nm). TEM images confirm the existence of mesotunnels on the silica pore walls. FT-IR and (29)Si solid-state NMR results reveal that these silica products have a large number of silanol groups.     

Length-based encoding of binary data in DNA

We developed a system to encode digital information in DNA polymers based on the partial restriction digest (PRD). Our encoding method relies on the length of the fragments obtained by the PRD rather than the actual content of the nucleotide sequence, thus eliminating the need for expensive sequencing machinery. In this letter, we report on the encoding of 12 bits of data in a DNA fragment of 110 nucleotides and the process of recovering the data.