Gas chromatography-electron ionization and chemical ionization mass spectrometric analysis of urinary phenmetrazine after derivatization with 4-carbethoxyhexafluorobutyryl chloride--a new derivative

Phenmetrazine is a central nervous system stimulant currently used as an anorectic agent. The drug is abused and is reported to cause death from overdose. We describe a new derivatization method for phenmetrazine using 4-carbethoxyhexafluorobutyryl chloride. Quantitation of urinary phenmetrazine can be easily achieved by using N-ethyl amphetamine as an internal standard. The electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of phenmetrazine showed a molecular ion at m/z 427 and a base peak at m/z 70. In the methane chemical ionization mass spectrum, the base peak was observed at m/z 428 (protonated molecular ion). In the electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of the internal standard, N-ethyl amphetamine we did not observe a molecular ion. However, in the chemical ionization mass spectrum, the protonated molecular ion at m/z 414 was the base peak. The retention time of derivatized phenmetrazine (8.4 min) was substantially longer than the retention time of the underivatized molecule. Moreover, underivatized phenmetrazine showed poor peak shape (substantial tailing) while derivatized phenmetrazine had excellent chromatographic properties. The within-run and between-run precisions of the assay were 2.6% and 3.1% respectively at a urinary phenmetrazine concentration of 10 micrograms/mL. The assay was linear for urinary phenmetrazine concentration of 1 to 100 micrograms/mL with a detection limit of 0.2 microgram/mL.     

The value of profundaplasty in the management of severe femoropopliteal occlusion

The author, the fifth superintendent of Alabama's Bryce Hospital since the Wyatt v. Stickney order was issued in 1972, discusses the major problems faced by an administrator in complying with the court-set standards. They relate to qualified mental health professionals, staffing ratios, staff attitudes, individualized treatment plans, and the hospital's negative image. He also discusses the role of the human rights committee and the hospital's goal of providing treatment of sufficient quality that the court order will be lifted.     

Implication of solvent structure in the interaction of poly (vinylalcohol) and short chain monohydric alcohols

Viscosity and density data have been obtained for aqueous solutions of a monodisperse sample of 90% hydrolysed poly (vinylalcohol) PvOH and for solutions of PvOH in short chain alcohol/water mixtures. The results are interpreted in terms of a ‘dynamic’ flowing volume and a ‘static’ partial molar volume for the macromolecule. Changes in the size of the dynamic and static volumes of the polymer in alcohol/water solvent mixtures are shown to correlate closely with reported changes in the degree of solvent structure. A tentative explanation of the role of solvent structure in the solution behaviour of the polymer is proposed.     

Numerical calculation of developing laminar flow in pipes of arbitrary curvature radius

Elliptic forms of the Navier-Stokes equations in rigorously formulated toroidal coordinates are solved numerically for laminar, incompressible, isothermal flow in curved pipes of small curvature radius and 90° deflection angle. As a special case, the flow through curved annuli is also considered in which the presence of the inner curved wall causes the appearance of two (rather than one) pair of cross-stream vortices. Recirculation in the main flow direction is observed at the outer curvature wall of a pipe with R_c/d = 1 and Re = 1800 over a deflection angle corresponding to 9° ≤ θ ≤ 21°. Flow reversal is attributed to the large and unfavorable longitudinal pressure gradient prevailing at the outer curvature wall over the first half of the pipe. Calculations show that the cross-steam flow in a strongly curved pipe can be as large as 80% of the bulk average velocity at θ = 45° but is reduced in magnitude between θ = 45° and 90°. The numerical procedure used for the present calculations is a special case of a more general method which will solve flows in arbitrary curvilinear orthogonal coordinates provided the appropriate scale factors and extra source terms are included. A detailed derivation of the difference equations in curvilinear orthogonal coordinates is, therefore, presented here.     

The Shape of Electron Bubbles in Liquid Helium and the Line Width of Optical Transitions

We present a calculation of the effect of zero-point and thermal fluctuations on the shape of electron bubbles in liquid helium. The results are used to determine the line shape for the 1S to 1P optical transition. The calculated line shape is in very good agreement with the experimental measurements of Grimes and Adams (Phys. Rev. B45, 2305 (1992)). PACS numbers: 67.40.Yv, 43.35.+d.     

Kinetics of thermal damage to a collagenous membrane under biaxial isotonic loading

Prior isothermal uniaxial isotonic tests on tendons reveal that higher temperatures hasten the rate of thermal denaturation whereas larger mechanical loads delay it; moreover, these findings suggest a time-temperature-load equivalency whereby similar levels of denaturation, as reflected by tissue shrinkage, can be attained via many combinations of heating time, temperature level, and mechanical loading. Yet, most tissues and organs experience multiaxial loads in vivo, and their microstructure differs significantly from that of tendons, thus, we must also evaluate the effects of multiaxial stresses on the kinetics of denaturation in other tissues. In this paper, we describe a new experimental approach for performing isothermal biaxial isotonic tests on thin sheet-like specimens and we report effects of various thermomechanical loads on the rate and amount of multiaxial shrinkage of bovine epicardium. Consistent with uniaxial studies, epicardial shrinkage generally increased sigmoidally with heating time, and a characteristic heating time revealed increases in the rate of shrinkage with higher temperature and decreases with larger biaxial loads. Although this characteristic time exhibited an Arrhenius-type character, time-temperature-load equivalency was not obtained when scaling time with this metric. General multiaxial thermomechanics is thus too complex to explain via a simple extension of uniaxial findings on tendons and there is a pressing need for more data and an appropriate theoretical framework.     

Salmonella Typhimurium definitive type 104. A multi-resistant Salmonella

The wide variety and the socio-economic and dietary importance of traditional fermented milk products of Ethiopia are discussed in this paper. Information on the microbiology of these products is sparse and has relevance to those organisms associated with spoilage and to those considered desirable for fermentation. There is a clear need to improve the production of African foods and beverages [Int. J. Food Microbiol. 18 (1993) 85]. The objective of this review was to document traditional technology used and information on the microbiology of the products, and to identify various constraints to the development and commercialisation of fermented milk products. Thereby the major problems and potential areas for improvement are pointed out. Ergo, the most important traditional product resembles yoghurt and, as the other traditional products, is prepared by "spontaneous" fermentation, commonly initiated by either "back slopping" or by repeated use of the same utensil. Other products include traditional fermented curd or ititu, traditional butter or kibe, neter kibe or traditional ghee, ayib resembling cottage cheese, arrera or defatted buttermilk and augat or traditional whey.     

APPLICATION OF EXTENDED EVOLUTIONARY PROGRAMMING TO SVC PLACEMENT

An extended evolutionary programming (EXEP) technique is proposed for optimal solution of the SVC placement in voltage stability enhancement. Multiple genetic transformation operators are used to ensure that the global optimal solution can be obtained. The problem is posed as the minimization of the function whose objectives are to increase the reactive power margin, the reactive power spinning reserve and the system voltage profile. At the same time it is required that the transmission losses are reduced and the additional cost of new SVC devices is minimal. All the operational inequality constraints are transformed to the objective function by using quadratic and cosine penalty functions. Numerical results show that EXEP technique is superior to simulated annealing(SA) technique.