Altered mRNA expression of the neuronal nitric oxide synthase gene in Hirschsprung''s disease

Deoxyribonuclease I (DNase I) is an actin monomer-sequestering actin binding protein (ABP) that inhibits the rate and extent of actin polymerisation in vitro by forming a high affinity, stoichiometric 1:1 complex. Using capillary zone electrophoresis (CZE), we have studied the interaction between G-actin and DNase I to evaluate the capability of CZE to determine the dissociation constant (K(d) value) for this interaction. We used (i) an uncoated fused-silica capillary and ultraviolet (UV) detection at 214 nm; (ii) a hydrophilic-coated capillary with UV detection at 214 nm; and (iii) a hydrophilic-coated capillary with laser-induced fluorescence (LIF) detection. Using procedure (ii), a K(d) value of approximately 0.03 microM was obtained by simulation of binding data. We conclude that CZE combined with a LIF detector has the capacity to extend the determination of K(d) values from the micromolar range to the nanomolar range. Subsequent determination of K(d) values for other actin-binding proteins should provide information on interactions between the binding sites on actin for these proteins and their spatial relationship.     

Ethylene glycol retention method for estimating specific surface area of adsorbent carbons

Ethylene glycol retention method, standardised by Dyal and Hendricks for clays and soils, has been used for determining specific surface areas of a large variety of adsorbent carbons differing widely in the extent as well as chemical nature of their surfaces. The proposed method yields values comparable with those obtained by the gaseous adsorption methods, irrespective of the oxygen contents of the carbons. A small amount of oxygen, probably within 0.2%, is essential to bring about proper wetting of the carbon by glycol.     

Electrochemical behaviour of cobalt and nickel complexes with ϵ-caprolactam at dropping mercury electrode

The kinetics of polarographic reduction of Co(II) and Ni(II) has been investigated in the presence of increasing concentration of complex forming agent viz ?-caprolactam at pH 6.2 under constant ionic strength. In both the cases the waves were found to be diffusion controlled and irreversible. The values of the kinetic parameters αn_a and k⁰_{f, h} have been calculated as a function of the ligand concentration. The polarographic wave was precisely proportional to the concentration up to 3.5 mM of the metal ions. Hence the straight line is useful as a calibration curve in quantitative analysis of these two metal ions. The error does not exceed more than ± 0.2% in any case.     

A BDD SAT solver for satisfiability testing: An industrial case study

The satisfiability problem (SAT) is a fundamental problem in mathematical logic, constraint satisfaction, VLSI engineering, and computing theory. Methods to solve the satisfiability problem play an important role in the development of computing theory and systems. In this paper, we give a BDD (Binary Decision Diagrams) SAT solver for practical asynchronous circuit design. The BDD SAT solver consists of a structural SAT formula preprocessor and a complete, incremental SAT algorithm that is able to find an optimal solution. The preprocessor compresses a large size SAT formula representing the circuit into a number of smaller SAT formulas. This avoids the problem of solving very large SAT formulas. Each small size SAT formula is solved by the BDD SAT algorithm efficiently. Eventually, the results of these subproblems are integrated together that contribute to the solution of the original problem. According to recent industrial assessments, this BDD SAT solver provides solutions to the practical, industrial asynchronous circuit design problems.This research is supported in part by the 1993 ACM/IEEE Design Automation Award, by the Alberta Microelectronics Graduate Scholarship, by the NSERC research grant OGP0046423, and was supported in part by the NSERC strategic grant MEF0045793.Presently, Jun Gu is on leave with the Department of Computer Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.     

Partial purification and characterisation of potato pectinesterase

Pectinesterase (EC 3.1.1.11) was extracted from potato (Solanum tuberosum var. Russet Burbank) tissue and purified 9.6-fold by ammonium sulphate precipitation and chromatography on Sephadex G-100. The enzyme preparation thus obtained has a molecular weight of 25,000, an apparent K_m of 0.09% for citrus pectin and a pH optimum of 7.5. NaCl is a positive modulator of the enzyme. The energy of activation of the enzyme is 6200 calories. A Q₁₀ of 1.33 is observed in the temperature range of 25 to 45°C, and the optimum temperature for the enzyme is 55°C.     

Correlations for trans-isomer formation during partial hydrogenation of oils and fats

Two empirical models are proposed to correlate the amount of trans-isomers formed during the partial hydrogenation of oils and fats as a function of the degree of hydrogenation and process variables. From minimal experimental data, constants for these models can be obtained and used to interpolate or extrapolate the trans-isomer data to predict the amount of trans-isomers formed during a partial hydrogenation or to select processing conditions for a desired amount of trans-unsaturation. The application of these models has been demonstrated using hydro-genation data for soybean and rapeseed oils.