Towards an Environmentally Acceptable Heterogeneous Catalytic Method of Producing Adipic Acid by the Oxidation of Hydrocarbons in Air

A survey is given of the catalytic methods potentially available for the production of adipic acid by the oxidation of readily available hydrocarbon precursors under environmentally benign conditions. Encouraging results are reported using H₂O₂ as oxidant and microporous FeAlPO-5 as catalyst at moderate temperatures.     

The synthesis and characterization of the molecular sieve SAPO-16 as well as other SAPO and CoAPO phases using bis(cyclopentadienyl) cobalt(III) hydroxide as a structure directing agent

The clathrate type molecular sieve SAPO-16 was prepared via a hydrothermal synthesis using bis(cyclopentadienyl)cobalt(III) hydroxide, Cp₂CoOH, as a template and characterized by XRD, FT-IR, UV-Vis and SEM. Additionally, the preparation and characterization of possibly new isostructural SAPO-UTD-3 and CoAPO-UTD-3 materials is reported.NSF Presidential Young Investigator 1991–1996.     

Effects of dietary casein and soy protein on metabolism of radiolabelled low density apolipoprotein B in rabbits

Rabbits fed semipurified diets containing casein have elevated plasma cholesterol levels compared to those fed soy protein. As part of continuing studies on the mechanism of casein-induced hypercholesterolemia, two groups of six rabbits were fed these diets for 14 to 16 weeks. Animals fed the casein diet were found to have significantly higher plasma concentrations of protein, cholesterol, triacylglycerol, phospholipid and apolipoprotein B (apo B) associated with low density lipoprotein (LDL) than those fed the soy protein diet. Kinetic studies showed that the fractional catabolic rate of LDL-apo B was significantly lower in animals fed casein than in those fed soy protein regardless of whether the tracer LDL was obtained from donors fed casein or soy protein. The production rate of LDL-apo B was higher in casein-fed animals but this was not statistically significant. These results show that the efficiency of removal of LDL is significantly reduced in animals fed casein compared to those fed soy protein, and that the source of LDL did not affect the efficiency of its subsequent removal. The acumulation of LDL in casein-fed animals is consistent with down-regulation of the LDL receptor.     

Synthesis of Kenyaite, Magadiite and Octosilicate Using Poly(ethylene glycol) as a Template

Three types of layered silicates, namely octosilicate, magadiite and kenyaite, were synthesized using poly(ethylene glycol) (PEG). The influence of reaction parameters, including alkali source, silica source, PEG molecular weight, reaction time and temperature, on the formation of these three phases was investigated. The results indicate that magadiite is preferred when (i) using NaOH as the alkali source and at a lower temperature (150°C), with fumed silica, tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), Ludox-AS 40 or colloidal sol acting as the silica source in the presence of PEG 200; (ii) using fumed silica as the silica source and PEG 300 as the template at 150°C; (iii) at a higher temperature (180°C), using PEG 200 as template and TEOS as the silica source; and (iv) at 180°C with a combination of PEG 300 and fumed silica. Compared to magadiite, kenyaite was favored at a higher temperature (180°C) with PEG 200 and NaOH, KOH or RbOH, while using fumed silica, silica gel, or colloidal sol as silica source; or at the lower temperature (150°C) using NaOH as alkali source, PEG 200 as template, and silica gel or silicic acid as the silica source. Octosilicate was obtained at 90°C with the combination of NaOH, PEG 200 and fumed silica.     

Factors influencing the photofading of commercial anthraquinone dyes in solution

The photofading of two anthraquinone dyes has been studied in aqueous solution using ultraviolet-visible absorption spectroscopy and flash photolysis. The influence of alcohol concentration, pH, atmosphere, photosensitisers and stabilisers have been examined and these lead to some important conclusions on the mechanism of dye fading. Essentially, the results indicate the photoexcited triplet state of the dye undergoes a process of either electron or hydrogen-atom abstraction depending on the nature of the environment. Other factors such as aggregation and singlet oxygen also appear to play an important role in solution photofading. The relevance of these results to photofading in a polymeric phase is discussed.     

Effect of fish oil on the fatty acid composition of human milk and maternal and infant erythrocytes

To examine the effect of fish oil supplementation on the fatty acid (FA) composition of human milk and maternal and infant erythrocytes, five lactating women were supplemented with 6 g of fish oil daily for 21d. Usual maternal diets contained 1,147 mg of total n−3 FA, with 120 mg from very long-chain (>C₁₈) n−3 FA. Supplementation increased dietary levels to 3,092 mg of total n−3 FA and 2,006 mg of very long-chain n−3 FA. Milk samples were collected daily, prior to fish oil ingestion, and at 4-h intervals on days 1, 7, 14 and 21. Milk n−3 FA content increased within 8 h and reached steady state levels within one week. The n−6 fatty acid content decreased. Erythrocyte eicosapentaenoic acid content increased from 0.24% to 1.4% (P<0.01) in mothers and from 0.11% to 0.70% (P<0.05) in infants. Docosapentaenoic acid increased from 1.4% to 2.2% (P<0.05) in mothers and from 0.30% to 0.78% (P<0.01) in infants. There was no significant change in docosahexaenoic acid or n−6 fatty acid content. Maternal platelet aggregation responses were variable. No differences in milk or plasma tocopherol levels were noted. Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Behavior of the western pine beetle during host colonization

After living ponderosa pines were baited with either female-infested bolts or synthetic pheromones,Dendroctonus brevicomis were caught on sticky screens throughout trapping periods of 15–46 days; however, large numbers of beetles were trapped during only a small portion (5–10 days) of these trapping periods. The most attractive portions of trees attacked contained 3–6 beetles dm², in galleries ca. 2 cm long. Catch increased following addition of males to female-infested bolts, supporting the hypothesis that male-produced frontalin is an attractive pheromone of the western pine beetle. Catch at bolts removed from trees under attack was strongly dependent upon levels of boring activity. We found no evidence of interruption of the response to attractants during host colonization.Coleoptera: Scolytidae. Trade names and commercial enterprises or products are mentioned solely for information and do not constitute endorsement by the U.S. Department of Agriculture or University of California.     

Poly(styrene-b-isobutylene-b-styrene) block copolymer ionomers (BCPI) and BCPI/silicate nanocomposites. 2. NaBCPI sol-gel polymerization templates

Polystyrene (PS) blocks in poly(styrene-b-isobutylene-b-styrene) (PS-PIB-PS) block copolymers were partially sulfonated and the acid groups converted to Na⁺SO₃⁻ groups to create ionomers. Then, dimethylacetamide was used to selectively swell the ionic PS domains and the swollen films were exposed to sol-gel reactive tetraethylorthosilicate solutions. (EtO)_4−xSi(OH)_x monomers then permeated films so that sol-gel reactions occurred within/around the ionic PS domains. Environmental scanning electron microscopy/energy dispersive X-ray spectroscopy investigations showed that silicate structures can be incorporated within the interior of the ionomer films. Differential scanning calorimetry studies indicated that there is no variance in the PIB block T_g with respect to ionomer formation, or with respect to silicate loading of the ionomer at low levels, which suggests that the silicate component does not reside in the PIB phase. ²³Na solid state NMR spectroscopy detected isolated Na⁺SO₃⁻ groups as well as aggregated SO₃⁻Na⁺ ion pairs for ‘as cast’ and ‘dry’ non-silicate containing ionomer samples. In a hydrated sample, almost all Na⁺ ions were solvent-separated. AFM analysis showed that phase separation exists, but that the degree of order is significantly less than that for hybrids based on the corresponding benzyltrimethylammonium ionomer. This frustrated morphology was also seen in the results of small angle X-ray scattering experiments. Given the scale of organic/inorganic heterogeneity, these hybrids are properly classified as nanocomposites.     

On the correspondence between abstract dialectical frameworks and nonmonotonic conditional logics

Annals of Mathematics and Artificial Intelligence - The exact relationship between formal argumentation and nonmonotonic logics is a research topic that keeps on eluding researchers despite recent...