Development of a smart algorithm for voltage monitoring and control[of power systems]

A method has been developed for the control of interconnected power system voltage based on monitoring of reactive power imbalances. The method has been derived using nonlinear analysis and therefore has the advantage of being applicable for large changes in reactive power or voltage. The method results in a very fast algorithm which can decide actions to be taken to recover prefault voltage levels     

Cystic fibrosis in Malay children--a report of three cases

A staining device for sectioned material supported on grids for viewing at the Transmission Electron Microscope is described. The method based in a double side sticky tape is inexpensive, rapid and clean. By using only pipettes and a double side sticky tape the best solution to the tedious problems of sections staining is obtained. The tape is discarded and the staining solution too. Precipitates have not been observed.     

Investigation of the Pade approximant-based wide-angle beampropagation method for accurate modeling of waveguiding circuits

An analytical and numerical study of the accuracy of the beam propagation method that includes approximate treatments of wide-angle propagation based on Pade rational functions is presented. The investigation identifies the error terms associated with a sequence of higher order operators and the range of validity of different approximant operators is studied through examination of two-dimensional (2-D) waveguide structures. An analytical model for the general error in Pade-based wide-angle schemes is developed and compared with numerical simulations of simple waveguiding devices for which the exact solution is known. Guidelines for determining the range of error pertinent to the Pade operator are established     

Quality of service provision in electric power distribution systems through reliability insurance

Traditional methods for regulating electricity distribution grids have several weaknesses in terms of incentives, risk allocation, consumer preferences, and the value of reliability. Rate of Return and Performance Based Regulation do not provide incentives for both cost efficiency and quality of service. These regulatory structures also allocate the risk of outages almost entirely to consumers and fail to incorporate consumer preferences for reliability/service quality. Additionally, investments in system reliability are not explicitly valued. This paper proposes an insurance scheme for reliability as a possible solution. Reliability insurance provides economically efficient investment incentives and alleviates consumers' reliability risk. Consumers provide economic signals to the distribution provider for their desired quality of service through insurance contracts. The value of reliability to consumers is thereby made transparent, allowing Distribution Companies (DisCo's) to make efficient investment decisions. Insurance also allocates outage risk to the DisCo (which controls the system), instead of consumers (who have little or no control over reliability). Reliability insurance effectively unbundles delivery and reliability services and enables consumers to receive differentiated reliability based upon their value for this service. This paper describes the potential for reliability insurance to improve both efficiency and risk allocation compared to conventional regulatory structures.     

Differential study of two strains of Toxoplasma gondii

This study aimed to differentiate between the virulent and avirulent strains of T. gondii by studying morphometric measurement using C.I.A.S., determination of the relative DNA content and extract, SDS poly acrylamide gel electrophoresis and isoenzyme on cellulose acetate gel. Identifying these differences may be useful in studying different disease types and in pathogenic mechanisms. Besides, the presence of common proteins between them may be of value for diagnostic purposes and for formulation of vaccines.     

Introducing electric power into a multidisciplinary curriculum for network industries

A qualitatively different graduate level curriculum for teaching electric power systems is needed. The motivation for such a new curriculum is outlined, and a specific program, now being implemented at Carnegie Mellon University, is described. The new curriculum: 1) provides students with a multidisciplinary introduction to the changing problems of the industry; 2) stresses the need for teaching systematic approaches to formulating power system problems; and 3) integrates teaching of the fundamentals for power systems with the fundamentals for other network industries. The program, referred to as the MS in Electric Power Systems (MSEPS) Program, is being developed as a special power-focused track within Carnegie Mellon's existing multidisciplinary Information Networking Institute (INI).     

Oxidation of serotonin by superoxide radical: implications to neurodegenerative brain disorders

Many new lines of evidence implicate both superoxide anion radical (O2*-) and biogenic amine neurotransmitters in the pathological mechanisms that underlie neuronal damage caused by methamphetamine (MA), glutamate-mediated oxidative toxicity, ischemia-reperfusion, and other neurodegenerative brain disorders. In this investigation the oxidation of 5-hydroxytryptamine (5-HT, serotonin) by an O2*--generating system (xanthine/xanthine oxidase) in buffered aqueous solution at pH 7.4 has been studied. The major product of the O2*--mediated oxidation of 5-HT is tryptamine-4,5-dione (T-4, 5-D). However, O2*- and H2O2, cogenerated by the xanthine oxidase-mediated oxidation of xanthine to uric acid, together react with trace levels of iron that contaminate buffer constituents to give a chemically ill-defined oxo-iron species. This species mediates the oxidation of 5-HT to a C(4)-centered carbocation intermediate that reacts with 5-HT to give 5,5'-dihydroxy-4, 4'-bitryptamine (4,4'-D) and with uric acid to give 9-[3-(2-aminoethyl)-5-hydroxy-1H-indol-4-yl]-2,6,8-triketo-1H,3H, 7H-purine (7) as the major products. These products differ from those formed in the HO*-mediated oxidation of 5-HT under similar conditions. When the reaction is carried out in the presence of the intraneuronal nucleophile glutathione (GSH), T-4,5-D is scavenged to give 7-(S-glutathionyl)tryptamine-4,5-dione, whereas the putative carbocation intermediate is scavenged to give 4-(S-glutathionyl)-5-hydroxytryptamine. T-4,5-D also reacts with the sulfhydryl residues of a model protein, alcohol dehydrogenase, and inhibits its activity. Previous investigators have proposed that T-4, 5-D is a serotonergic neurotoxin. This raises the possibility that T-4,5-D and perhaps other putative intraneuronal metabolites formed by the O2*-/H2O2/oxo-iron-mediated oxidations of 5-HT might be endotoxins that contribute to neurodegeneration in brain regions innervated by serotonergic neurons caused by MA, ischemia-reperfusion, and other neurodegenerative brain disorders.