Global stability of autonomous and nonautonomous hepatitis B virus models in patchy environment

Autonomous and nonautonomous hepatitis B virus infection models in patchy environment are investigated respectively to illustrate the influences of population migration and almost periodicity for infection rate on the spread of hepatitis B virus. The basic reproduction number is determined and asymptotic stabilities of disease-free and endemic equilibria are established in case of autonomous system. Moreover, in the nonautonomous system case, existence and global attractivity of almost periodic solution for this system are studied. Finally, feasibility of main theoretical results is showed with the aid of numerical examples for model with two patches.     

A platform method for plasmid isoforms analysis by capillary gel electrophoresis

In the production of novel biological products, plasmids are often engineered into delivery vectors for target genes, which can be used directly as vaccines or as intermediate products for gene/cell therapy. Plasmid DNA exists in several topological forms such as supercoiled, linear, and open circular. As supercoiled plasmid shows the highest efficiency in transfecting eukaryotic cells, the content of supercoiled plasmids becomes an important indicator of plasmid quality. CGE is an effective analysis method for separating different topological structures of plasmids. For the purpose of providing plasmid manufacturers and regulatory agencies with an efficient and readily used tool for monitoring the quality of plasmids, this article identifies the optimal separation and detection conditions of CGE, presents a platform-based plasmid analytical method, and uses plasmid of different sizes to verify the feasibility of this method. In terms of detector, the LIF detector has obvious advantages over the ultraviolet detector in sensitivity and resolution. Using the optimal CE condition (10× gel buffer), baseline separation of different topological forms and impurities can be achieved for different plasmid sizes (5.9, 7.8, 15.4 kb). In addition, 6.5 kb plasmid was used to compare the different separation technologies such as CGE-LIF, ion exchange chromatography and agarose gel electrophoresis. The result shows that CGE-LIF can provide better resolution and quantitation accuracy than ion exchange chromatography and agarose gel electrophoresis. CGE-LIF, as a quick and convenient method to separate and quantify plasmids, has the advantages of high sensitivity, high resolution, and high quantitative accuracy. Therefore, it is ideal for analysis of plasmids with different sizes, and it can also be used as a platform method for manufacturers and regulatory agencies to monitor the purity and stability of plasmids.     

1,1-二氨基-2,2-二硝基乙烯的比热容、热力学性质及绝热至爆时间研究

应用Micro-DSCⅢ微热量仪的两种连续比热容测定模式对1,1-二氨基-2,2-二硝基乙烯(FOX-7)比热容进行了测定. 得到298.15 K时FOX-7的标准摩尔比热容分别为176.56和176.02 J•mol^－1•K^－1, 相对偏差为0.31%. 运用Gaussian 03W程序的DFT-RB3LYP/6-311＋＋G**方法对FOX-7在283～353 K温度范围内进行了比热容理论计算, 结果为147.11～170.54 J•mol^－1•K^－1, 与Micro-DSCⅢ微热量仪测定值偏差在13.27%～15.46%之间. 用测得的比热容方程计算了298.15 K为基础的FOX-7的热力学函数并得到了绝热至爆时间.     

Thermal behavior of 3,4,5-triamino-1,2,4-triazole dinitramide

The thermal decomposition behavior of 3,4,5-triamino-1,2,4-triazole dinitramide was measured using a C-500 type Calvet microcalorimeter at four different temperatures under atmospheric pressure. The apparent activation energy and pre-exponential factor of the exothermic decomposition reaction are 165.57 kJ mol⁻¹ and 10^18.04 s⁻¹, respectively. The critical temperature of thermal explosion is 431.71 K. The entropy of activation (ΔS ^≠), enthalpy of activation (ΔH ^≠), and free energy of activation (ΔG ^≠) are 97.19 J mol⁻¹ K⁻¹, 161.90 kJ mol⁻¹, and 118.98 kJ mol⁻¹, respectively. The self-accelerating decomposition temperature (T _SADT) is 422.28 K. The specific heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide was determined with a micro-DSC method and a theoretical calculation method. Specific heat capacity (J g⁻¹ K⁻¹) equation is C _p = 0.252 + 3.131 × 10⁻³  T (283.1 K < T < 353.2 K). The molar heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide is 264.52 J mol⁻¹ K⁻¹ at 298.15 K. The adiabatic time-to-explosion of 3,4,5-triamino-1,2,4-triazole dinitramide is calculated to be a certain value between 123.36 and 128.56 s.     

Thermochemical properties of hydrazinium dipicrylamine in N-methyl pyrrolidone and dimethyl sulfoxide

The enthalpies of dissolution for Hydrazinium Dipicrylamine (HDPA) in N-methyl pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K. Empirical formulae for the calculation of the enthalpies of dissolution (Δ_diss H) were obtained from the experimental data of the dissolution processes of HDPA in NMP and DMSO. The linear relationships between the rate (k) and the amount of substance (a) were found. The corresponding kinetic equations describing the two dissolution processes were $ {{\text{d}\alpha } \mathord{\left/ {\vphantom {{\text{d}\alpha} {\text{d}t}}} \right. \kern-0pt} {\text{d}t}} = 10^{ - 2.71}\left( {1 - \alpha } \right)^{1.23} $ d α / d t = 10 ? 2.71 ( 1 ? α ) 1.23 for the dissolution of HDPA in NMP, and $ {{\text{d}\alpha } \mathord{\left/ {\vphantom {{\text{d}\alpha} {\text{d}t}}} \right. \kern-0pt} {\text{d}t}} = 10^{ - 2.58}\left( {1 - \alpha } \right)^{0.81} $ d α / d t = 10 ? 2.58 ( 1 ? α ) 0.81 for the dissolution of HDPA in DMSO, respectively.     

Synthesis and thermal behaviors of 1,3-bis(4-aminophenoxy)benzene (TPER) and polyimide based on TPER and pyromellitic dianhydride

1,3-Bis(4-aminophenoxy)benzene (TPER) and poly(amic acid) based on TPER and pyromellitic dianhydride (PMDA) were synthesized. After imidization of the poly(amic acid), polyimide based on TPER and PMDA was obtained. The melting process and the specific heat capacity (C _p) of TPER were examined by DSC and microcalorimetry, respectively. The melting enthalpy, the melting entropy, and the C _p for TPER were obtained. The enthalpy change, the entropy change, and the Gibbs free energy change for TPER were obtained within 283 and 353 K. The thermal decomposition reaction mechanism of the polyimide is classified from the TG–DTG experimental data, and the thermokinetic parameters of the thermal decomposition reaction are E _a = 296.87 kJ mol^?1and log (A/s^?1) = 14.41.     

Synthesis,Crystal Structure and Luminescent Property of a 2-D Hybrid Constructed from [Pb_2I_4] Subunits

A novel organic-inorganic hybrid compound, [Pb2I4（bipy）], （bipy = 4,4′-bipyridine）, was synthesized by self-assembly and its structure was determined by X-ray crystallography method The crystal belongs to the monoclinic system, space group P2 1/c with α = 4.4691（9）, b = 15.385（3）, c = 14.136（3） A, β = 93.75（3）°, V= 969.9（3） A^3, Mr = 1078.16, Dc= 3.692 g/cm^3, F（000） = 916, μ = 23.688 mm^-1, Z = 2, the final R = 0.0395 and wR = 0.0887 for 1557 observed reflections with I 〉 2σ（I）. The title compound presents a two-dimensional layer-like structure constructed from [PbI5N] octahedron and bis-bridging ligand 4,4′-bipyridine. The fluorescence of the title compound is also discussed in this communication.