Anodic substitutions in emulsions under phase transfer catalysis conditions. I. Cyanation of dimethoxybenzenes

An emulsion electrolysis technique in the two-phase system water-dichloromethane containing NaCN and a phase transfer agent (PTA) has been examined with 1,2- and 1,3-dimethoxybenzenes as a function of various parameters (nature of Q⁺, X^–, anodic potential, cyanide ion concentration in the organic phase, preparative current potential curves). The anodic cyanation results indicate that the anode wetting phenomena, the extraction of cyanide ion and the competitive oxidation of X^– are the determining factors. It is shown that the best criterion for a successful anodic cyanation is to operate under conditions of maximum coverage of the anode by the organic layer. Among all the PTA studied (cetyltrimethylammonium bromide,nBu4N⁺HSO ₄ ^– ,nBuP⁺₃Br^–, benzethonium chloride and A 336), A 336, a very hydrophobic PTA, affords the best chemical (81%) and current (77%) yields with 1,2,-dimethoxybenzene.     

Identification of β-sitosterol,campesterol, and stigmasterol in human serum

The presence of 3 plant sterols, β-sitosterol, campesterol, and stigmasterol, has been demonstrated in the serum from 2 patients with β-sitosterolemia and xanthomatosis.     

Effect of heated fat upon metabolism of 1-14C-acetate in the rat

Groups of rats were prefed for 18 weeks with fresh or heated corn oil (≈5% nonurea adduct) at 10, 20 and 30% protein levels and at 10% protein+2% cellulose; 1-¹⁴C-sodium acetate was injected intraperitonially into each animal and the radioactivity was measured in expelled CO₂ and also in the lipid fractions of liver. In the groups of rats fed 10% protein, one-half of the administered radioactivity was found 50 min after acetate injection into rats fed fresh oil, whereas 90 min were required to reach the same level in rats fed heated oil. The same trend was found in all the groups of rats receiving different protein levels. The conversion of acetate to CO₂ was significantly higher at a 10% dietary protein level than at the 20 or 30%, but there appeared to be no significant difference in the conversions at the 20 and 30% protein levels. However addition of 2% cellulose to the 10% dietary protein level significantly increased the conversion of the acetate to CO₂ in rats fed heated oil. The livers of animals receiving heated fat diets had a higher lipid content, mainly triglyceride. When the liver lipids from rats fed fresh corn oil were separated by argentation thin layer chromatography, the bulk of the radioactivity was found in the saturated fractions. Monoene, diene and triene fractions from the liver lipid of rats fed heated oil had almost twice the radioactivity of those from fresh oil, suggesting the preferential utilization of acetate in the synthesis of these unsaturated fatty acids. One of seven papers presented in the symposium “Biological Significance of Autoxidized and Polymerized Oils”, JOCS-AOCS Joint Meeting, Los Angeles, April 1972.     

Parametric Analysis of a Novel Architecture of Phase Locked Loop for Communication System

The work proposed parametric analysis of a novel architecture of phase locked loop (PLL) for pure signal synthesis. It has been widely used in wireless communication systems due to the high frequency resolution and the short locking time. First, we presented a mathematical and accurate model of noise in PLL with take into account noise of its component. Then we predicted output phase noise in term of its parameters. Finally, we described as effective technique for noise in fractional PLL by CppSim simulator. The output phase noise has been reduced from \(-154\) to \(-159\,\) dBc/MHz at 20 MHz offset. The proposed behavioral simulation results show improvement around 5 dBc/MHz. In future, this technique can also be implemented in hybrid PLL.     

Parametric Analysis to Reduce Phase Noise of Frequency Synthesizers for Wireless Communication System

The aim of this paper is analysis and presenting a technique to reduce phase noise of frequency synthesizer for pure signal synthesis. To reduce phase noise of synthesizer, first, we present a mathematical and accurate model of phase noise in phase locked loop based frequency synthesizer with take into account noise of its component. Then we predict output phase noise in term of its parameters. Finally, we describe as effective technique for phase noise in frequency synthesizer. The simulation results show the performance of the frequency synthesizer for the High Speed communication system.     

Effect of Interlayer Interaction on the Specific Heat of High-T c Superconductors

The effect of interlayer interactions on the electronic specific heat of high-T _c layered superconductors has been studied within the framework of the Hirsch model. In the present paper we extend our previous work in order to evaluate the expression for specific heat. It is shown that the inclusion of interlayer interactions suppresses the height of the jump in the specific heat at T _c.     

Assessing the information environment in intensive care units

This paper describes the development and application of a methodology for evaluating how physicians and nurses view the usefulness of various sources of patient information available within a hospital intensive care unit (ICU). The methodology encompasses semi-structured interviews, task analysis, a simulated case study of a critically ill patient, verbal protocol analysis, questionnaire responses based on both past experiences in the ICU and performance on the simulated task, and a post-task interview. Eleven nurses and six physicians participated in the study. Analysis of the questionnaires revealed significant differences in the rankings of the information sources by both the nurses and the physicians on each of seven evaluation criteria. Significant differences were also found among both the physicians and the nurses in rankings of the relative importance of the individual information sources for meeting task requirements. A framework for describing information gathering applicable to critical care environments was proposed as a means for better understanding how information sources are used. Overall, the methodology was found to be useful in terms of providing valuable data regarding the utility and usability of information sources. The importance of using a systematic approach for assessing the usefulness of information sources, particularly from the perspectives of performing design interventions and predicting the effectiveness of new information technologies, as well as the limitations in adopting this type of approach, are also discussed.     

Study of formation of silicon carbide in the Acheson process

Formation of silicon carbide in the Acheson process was studied using a mass transfer model which has been developed in this study. The century old Acheson process is still used for the mass production of silicon carbide. A heat resistance furnace is used in the Acheson process which uses sand and petroleum coke as major raw materials. It is a highly energy intensive process. No mass transfer model is available for this process. Therefore, a mass transfer model has been developed to study the mass transfer aspects of the process along with heat transfer. The reaction kinetics of silicon carbide formation has been taken from the literature. It has been shown that reaction kinetics has a reasonable influence on the process efficiency. The effect of various parameters on the process such as total gas pressure, presence of silicon carbide in the initial charge, etc. has been studied. A graphical user interface has also been developed for the Acheson process to make the computer code user friendly.     

Some Approximations for the Noncentral-F Distribution

Among the various approximations for the noncentral-F distribution. the best known are the computationally simpler approximation due to Severo and Zelen [18] and Laubscher [9], which requires only the normal distribution, and a more accurate approximation due to Tiku [21], which requires the F distribution. Thcsr approximations are systematically evaluated. Some variations of these approximations are considered and found to he of comparable accuracy. An Edgeworth-acries approximation, which requires only the normal distribution, is developed and sren to be superior in accuracy. A FORTRAN-subroutine for the Edgeworth-series approximation is given.     

Mutational Consequences on Replication of M13 Constructs Containing Isomeric Diol Epoxide Adducts in E. coli

Eight isomeric dGuo and eight dAdo adducts resulting from cis and trans opening of each of the four optically active diol epoxides (DEs) derived from benzo[ a ]pyrene (B a P) and benzo[ c ]phenanthrene (B c Ph) were placed in each of two 16-mer DNA sequences to give 32 modified oligonucleotides, which were ligated into M13mp7L2 and allowed to replicate in SOS-induced Escherichia coli . The effects of parent hydrocarbon, adduct stereochemistry, and sequence context on mutagenic response are highly interdependent. B a P DE adducts are generally more mutagenic than the corresponding B c Ph adducts. The mutational frequency is generally larger for cis - relative to trans -opened DE adducts of both dGuo and dAdo. In a ～TA*G～ context, B c Ph DE dAdo adducts (A*) with R configuration at the site of attachment to the adenine base produced very few substitution mutations when compared with adducts having S configuration. This configurational effect is not observed for B a P DE dAdo adducts, nor for B a P or B c Ph dGuo adducts.