A study of the concentration of micro and macro nutrients in blenderised liquid diet in nasogastric feeding

Neutron activation analysis was used to determine the amount of macro (Na, K, P, Ca) and trace elements (Fe, Co, Zn, Mo, Se) present in the blenderised liquid diet in nasogastric feeding of patients having throat cancer.     

Low dose 60Co gamma-irradiation effects on electronic carrier transport and DC characteristics of AlGaN/GaN high-electron-mobility transistors

The impact of internal irradiation with secondary Compton electrons, generated by gamma-photons, on the characteristics of III-N/GaN-based devices was explored. N-channel AlGaN/GaN high-electron-mobility transistors (HEMTs) were exposed to gamma-radiation from a ⁶⁰Co source for doses up to 600?Gy. Temperature-dependent electron beam-induced current (EBIC) was employed to measure minority carrier transport properties. For low doses below ～250?Gy, the minority carrier diffusion length in AlGaN/GaN HEMTs is shown to increase by about 40%. This increase is likely due to longer minority carrier lifetime induced by internal Compton electron irradiation. An associated decrease in activation energy, extracted from temperature-dependent EBIC, was also found. The obtained increase in transconductance and decrease in gate leakage current indicate an improvement in performance of the devices after low doses of irradiation. For high doses of gamma-irradiation, above ～300?Gy, the performance of HEMTs showed a deterioration. The deterioration results from the onset of increased carrier scattering due to additional radiation-induced defects, as is translated in a decrease of minority carrier diffusion length.     

Preparation and evaluation of novel stationary phases for improved chromatographic purification of pneumocandin B0

Preparation and evaluation of a number of stationary phases for improved chromatographic purification of pneumocandin B0, a key intermediate in the synthesis of the antifungal agent, Cancidas, has led to the identification of several materials with potential for improved performance.     

Development of a gradient elution preparative high performance liquid chromatography method for the recovery of the antibiotic ertapenem from crystallization process streams

A gradient elution preparative chromatography method was developed for the recovery of the antibiotic ertapenem from crystallization mother-liquor streams. The preparative HPLC method that was developed on the lab-scale employs an analytical size column of conventional dimensions (25 cm x 0.46 cm) packed with Kromasil C8 stationary phase. Gradient elution was used with aqueous acetic acid and acetonitrile as mobile phases. A target of processing approximately 30 mg of ertapenem per half an hour at a flow rate of 1.5 mL/min with high yield and adequate rejection of all major impurities was achieved. This corresponds to a productivity of approximately 0.6 kg ertapenem as free acid per kilogram of stationary phase per day (kkd). The scalability of the method was demonstrated by using a 5 cm i.d. column configuration to generate 10 g of purified ertapenem. This work complements a previous study improving on the productivity and throughput of the method by employing gradient elution and the use of crystallization to remove some key impurities that are chromatographically difficult to resolve [A. Vailaya, P. Sajonz, O. Sudah, V. Capodanno, R. Helmy, F.D. Antia, J. Chromatogr. A 1079 (2005) 80].     

Comprehensive study of the effect of composition on the flame-retardant activity of antimony oxide and halogenated hydrocarbons in thermoplastic polymers

Flame retardance has been studied in the systems (a) antimony (III) oxide and decabromobiphenyl in acrylonitrile-butadiene-styrene terpolymer (ABS) and (b) antimony (III) oxide and chlorinated paraffin in high-density polyethylene (HDPE). Values of limiting oxygen index for over 70 compositions in each system have been measured and fitted by fourth-order polynomials. The triangular plots of these polynomials show complexities of the systems which cannot be revealed by traditional methods. Optimum atomic ratios for this synergistic system were found to be higher than the commonly accepted value of 3: Br/Sb = 9 and Cl/Sb = 6–7. ABS was found to be more amenable to flame retardance than HDPE; possible reasons are discussed.     

Bound state solutions of d-dimensional Schrdinger equation with Eckart potential plus modified deformed Hylleraas potential

We study the d-dimensional Schrdinger equation for Eckart plus modified deformed Hylleraas potentials using the generalized parametric form of Nikiforov-Uvarov method.We obtain energy eigenvalues and the corresponding wave function expressed in terms of a Jacobi polynomial.We also discuss two special cases of this potential comprised of the Hulthen potential and the Rosen-Morse potential in three dimensions.Numerical results are also computed for the energy spectrum and the potentials.     

The combined action of aluminium oxides and halogen compounds as flame retardants

Studies have been made of the effects of mixtures of aluminium oxides and organic halogen compounds on the flammability of polyethylene and an acrylonitrile-butadiene-styrene copolymer (ABS). There is considerable synergism in the flame-retardant action, particularly when anhydrous alumina and a bromine compound are introduced into ABS. The addition of relatively small amounts of alumina prevents the saturation effects otherwise observed when increasing quantities of halogen compounds on their own are incorporated into the polymers. Chemical interaction between aluminium oxides and the halogens occurs in the condensed phase.