Lipoidal biopterin compounds

" The present invention provides lipoidal biopterin and tetrahydrobiopterin compounds of the general structure: ##STR1## wherein --R is absent when ring B has two double bonds, PA0 --R is hydrogen when the two double bonds in ring B are absent, and PA0 --R' and R"" are selected from saturated or unsaturated, cyclic or non-cyclic hydrocarbons of 1 to 31 carbon units. The compounds provided by this invention are oil soluble and can readily be formulated as an oil based pharmaceutical useful for the treatment of phenylketonuria, Parkinsonism, depression, senile dementia, Alzheimer's disease and related biopterin deficiency diseases. "Board of Regents, University of Texas Syste

Properties and Cycle Performance of Refrigerant Blends Operating Near and Above the Refrigerant Critical Point, Task 1: Refrigerant Properties

The main goal of this project was to investigate and compare the performance of an R410A air conditioner to that of an R22 air conditioner, with specific interest in performance at high ambient temperatures at which the condenser of the R410A system may be operating above the refrigerant's critical point. Part 1 of this project consisted of measuring thermodynamic properties R125, R410A and R507A, measuring viscosity and thermal conductivity of R410A and R507A and comparing data to mixture models in NIST REFPROP database. For R125, isochoric (constant volume) heat capacity was measured over a temperature range of 305 to 397 K (32 to 124 C) at pressures up to 20 MPa. For R410A, isochoric heat capacity was measured along 8 isochores with a temperature range of 303 to 397 K (30 to 124 C) at pressures up to 18 MPa. Pressure-density-temperature was also measured along 14 isochores over a temperature range of 200 to 400 K (-73 to 127 C) at pressures up to 35 MPa and thermal conductivity along 6 isotherms over a temperature range of 301 to 404 K (28 to 131 C) with pressures to 38 MPa. For R507A, viscosity was measured along 5 isotherms over a temperature range of 301 to 421 K (28 to 148 C) at pressures up to 83 MPa and thermal conductivity along 6 isotherms over a temperature range of 301 to 404 K (28 to 131 C) with pressures to 38 MPa. Mixture models were developed to calculate the thermodynamic properties of HFC refrigerant mixtures containing R32, R125, R134a and/or R125. The form of the model is the same for all the blends considered, but blend-specific mixing functions are required for the blends R32/125 (R410 blends) and R32/134a (a constituent binary of R407 blends). The systems R125/134a, R125/143a, R134a/143a, and R134a/152a share a common, generalized mixing function. The new equation of state for R125 is believed to be the most accurate and comprehensive formulation of the properties for that fluid. Likewise, the mixture model developed in this work is the latest state-of-the-art for thermodynamic properties of HFC refrigerant blends. These models were incorporated into version 7 of NIST REFPROP database

Measurement and Correlation of Densities and Dynamic Viscosities of Perfluoropolyether Oils

The densities and dynamic viscosities of five different polydisperse perfluoropolyethers (PFPE) were measured at atmospheric pressure over the combined temperature range 263.15–373.15 K. For one PFPE being considered as a high-temperature high-pressure viscosity standard reference material, measurements were made on two separate samples to examine the lot-to-lot variability in density and viscosity; significant variability was observed only for the viscosity data. Experimental data were correlated as a function of temperature. A simple quadratic equation was used for density, while three equations (DIPPR, VFT, and Waterman) were applied to the viscosity data. The DIPPR equation represented the viscosity data with deviations approximately an order of magnitude lower than the other two equations

Die Transporteigenschaften von fluiden Stoffen Schlussbericht

With 8 figs., 6 tabs., 66 refs.Available from TIB Hannover: FR 4597 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman