Engineering A Uranyl‐Specific Binding Protein from NikR

A new pick‐up line : The first uranyl‐selective DNA‐binding protein is designed using the E. coli nickel(II)‐responsive protein NikR as the template. The resulting NikR′ protein binds uranyl (see picture) with a dissociation constant K_d=53 nM and selectively binds to DNA in the presence of uranyl.

     

Polyhedral analysis for the two-item uncapacitated lot-sizing problem with one-way substitution

We consider a production planning problem for two items where the high quality item can substitute the demand for the low quality item. Given the number of periods, the demands, the production, inventory holding, setup and substitution costs, the problem is to find a minimum cost production and substitution plan. This problem generalizes the well-known uncapacitated lot-sizing problem. We study the projection of the feasible set onto the space of production and setup variables and derive a family of facet defining inequalities for the associated convex hull. We prove that these inequalities together with the trivial facet defining inequalities describe the convex hull of the projection if the number of periods is two. We present the results of a computational study and discuss the quality of the bounds given by the linear programming relaxation of the model strengthened with these facet defining inequalities for larger number of periods.     

Synthesis and Structure of Two New Mycolactones Isolated from M. ulcerans subsp. shinshuense

Two new mycolactones, mycolactones S1 and S2, were isolated from culture agar of Mycobacterium ulcerans subsp. shinshuense. Their structures were established in a three-step procedure: (1) probable structures were speculated from MS analysis; (2) candidates were synthesized; (3) HPLC profiles were established for identification of the natural products. Newly isolated mycolactones correspond to the "oxidized forms" of mycolactone A/B, the causative toxin of Buruli ulcer, isolated from Mycobacterium ulcerans.     

Influence of polyelectrolytes on crystallization of zeolite Y

In this study, the influence of polyelectrolytes on the crystallization of zeolite Y is investigated. The prepared synthesis mixtures are aged at room temperature for 24 h and then left to crystallize. The compositional and structural information are provided by elemental analysis obtained by ICP, X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), particle size analyzer and adsorption and desorption isotherms of nitrogen by a volumetric adsorption instrument. The first group of synthesis studies is conducted by using solutions containing no additive (WA), nonionic (NI), 100% anionic (100A), and 100% cationic (100C) polyelectrolytes. The crystallization temperature and crystallization time are kept at 100 ºC and 48 h, respectively. The experimental results show that nonionic polyelectrolyte has the most influence on the crystallization of zeolite NaY. In the second group of synthesis studies, the effects of polyelectrolytes with various degrees of anionic properties (10%, 50% and 70%) of the same chemical structure are investigated by conducting crystallization experiments at 100 °C for a duration of 48 h. The results suggest that; particle size, crystallinity and BET surface area (S_BET) can be controlled by adding anionic polyelectrolytes to the solution.     

Photophysical properties of 5H-dibenzo(a,d)cyclohepten-5-one in different solutions

A number of photophysical properties of 5H-dibenzo(a,d)cyclohepten-5-one have been measured for the first time including the prompt and P-type delayed fluorescence, and triplet-triplet absorption. Decay parameters, for the triplet-state of this molecule, have also been measured in different quenching conditions. The results are discussed and compared for those of similar molecules.     

Lectin attached affinity cryogels for amyloglucosidase adsorption

Abstract

Preparation of poly[ethylene glycol dimethacrylate (EGDMA)-glycidyl methacrylate (GMA)] cryogel and its usability for amyloglucosidase adsorption were investigated. Cryogels were prepared by cryocopolymerization technique and then functionalized by lectin concanavalin A (Con A). The synthesized cryogel was characterized by FTIR, SEM and EDX analysis and then used for adsorption of amyloglucosidase in a continuous flow system. The maximal amyloglucosidase adsorption efficiency of Con A attached cryogel was found to be as 30.50?mg/g cryogel. Con A modified cryogels were used repeatedly for 30 times without any significant decrease at the amyloglucosidase adsorption capacity. SDS-PAGE and activity studies confirmed that the desorbed amyloglucosidase was active and retained 90% of its initial activity after the adsorption/desorption processes.     

堆泵浦~3He－Ar－Xe体系的激光原理性实验

介绍了在ＣＦＢＲ－Ⅱ脉冲堆上进行的￣３Ｈｅ─Ａｒ─Ｘｅ体系的激光演示实验。当热中子注量率６×１０￣（１４）／ｃｍ￣２·ｓ，气体组配￣３Ｈｅ：Ａｒ：Ｘｅ＝３４．７：３４．７：０．２６７（ｋＰａ）时，获得波长λ＝１．７３μｍ、脉宽（ＦＷＨＭ）平均值７３８μｓ、峰值功率为毫瓦级的激光输出。同时对测得的光信号及其特性进行了分析。     

Sensitivity enhancement in flame atomic absorption spectrometry for determination of copper in human thyroid tissues.

Various designs of quartz tube in a slotted tube atom trap were examined for improving the sensitivity of flame AAS. A 3.5-fold enhancement in the sensitivity was obtained by using the optimized method. The method was applied to the determination of Cu in cancerous and non-cancerous human thyroid tissues. The Cu concentrations of the cancerous samples tended to increase compared with the non-cancerous samples. Zn concentrations of the same tissues were also determined.     

Acid–base interactions and swelling of cellulose fibers in organic liquids

Drago’s acid–base approach was used to quantify the hydrogen bonding interactions in solvent swelling of cellulose fibers. The fiber swelling was correlated with acid–base, dispersive interactions and solvent molar volume. The acid–base interaction potentials of solvents were expressed in terms of their electron pair donor and acceptor numbers. The acid–base interaction terms of cellulosic materials were determined by using: (1) Flory–Huggins; (2) multiple regression models. We have used the swelling data of Mantanis and coworkers, which were based on the equilibrium liquid holding capacities of various compressed fibers in water and series of organic solvents. According to our interpretations, acid–base interactions and molar volume parameters were the major contributors to the overall solubility parameter. Acid–base interaction terms were balanced in alpha-cellulose sample. However spruce wood and sulfite pulp samples were more acidic than basic and therefore swollen better in organic basic solvents. For a good swelling behavior solvent must have high electron pair donor number/acceptor number ratio and high electron pair donor number–acceptor number difference.     

Gamma radiolysis of Methyl Red solution and reaction induced by γ-irradiated NaCl in Methyl Red

The -radiolysis of Methyl Red solution in HCl medium at pH=2 has been studied along with energy transfer reaction brought about byF and hole centers of -irradiated NaCl. The G-values for degradation of the azo dye indicator by radiolysis and -irradiated salt were determined as 9·10^–1 and 4.8·10^–3, respectively. The kinetic rate constants (k) of degradation are evaluated as 2·10^–5 rad^–1 in the case of direct radiolysis, while for the irradiated salt it is 2·10^–7 rad^–1. The extent of degradation by direct -radiolysis is 100–200 times greater as compared to that by the -irradiated salt. The same mechanism is proposed for radiolysis as well as the reaction induced by -irradiated sodium chloride.