Influence of titania on zirconia promoted Cu/SiO2 catalysts for methanol synthesis from CO/H2 and CO2/H2

The effects of adding mixtures of titania and zirconia on the methanol synthesis activity and selectivity of Cu/SiO₂ were investigated. The synthesis of methanol from both CO/H₂ and CO₂/H₂ mixtures was examined at 0.65 MPa and temperatures between 448 and 573 K. For CO hydrogenation, the addition of ZrO₂ alone increased the methanol synthesis activity of Cu/SiO₂ by up to three-fold. Substitution of a portion of the ZrO₂ by TiO₂ decreased the methanol synthesis activity of the catalyst relative to that observed when only ZrO₂ is added. ZrO₂ addition also enhanced the methane synthesis activity by as much as seven fold. In the case of CO₂ hydrogenation, the maximum methanol synthesis activity is achieved when a 50/50 wt% mixture of ZrO₂ and TiO₂ is added to Cu/SiO₂. Neither the presence of the oxide additive nor its composition had any effect on the activity of the reverse water–gas-shift reaction, which suggests that this reaction proceeds only on Cu. The observed effects of ZrO₂ and TiO₂ on the catalytic activity of methanol synthesis from CO and CO₂, and methane synthesis from CO, are interpreted in terms of the strength and concentration of acidic and basic groups on the surface of the dispersed oxide.     

An in situ infrared study of NO reduction by C3H8 over Fe‐ZSM‐5

The interactions of NO, O₂ and NO₂ with Fe‐ZSM‐5, as well as the reduction of NO by C₃H₈ in the presence of O₂, have been investigated using in situ infrared spectroscopy. The sample of Fe‐ZSM‐5 (Fe/Al =0.56) was prepared by solid‐state ion exchange. NO adsorption in the absence of O₂ produces only mono‐ and dinitrosyl species associated with Fe²⁺ cations. Adsorbed NO₂/NO₃ species are formed via the reaction of adsorbed O₂ with gas‐phase NO or by the adsorption of gas‐phase NO₂. The reduction of NO in the presence of O₂ begins with the reaction of gas‐phase C₃H₈ with adsorbed NO₂/NO₃ species to form a nitrogen‐containing polymeric species. A reaction pathway is proposed for the catalyzed reduction of NO by C₃H₈ in the presence of O₂. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of hydrogen treatment on the porous structure of Al2O3-SnO2 system

The results of an investigation of the porous structure of the Al₂O₃-SnO₂ system and its properties after hydrogen treatment are presented. Pore size distribution was determined on the basis of low temperature nitrogen adsorption measurements. Reduction of the system by H₂ leads to a decrease of the parameters defining porous structure. We conclude that this is due to the reduction of Sn(IV) species to oxidation state II.     

Low temperature plasma surface alloying of medical grade austenitic stainless steel with carbon and nitrogen

Low temperature surface alloying with either nitrogen (nitriding) or carbon (carburizing) has been successfully employed in hardening AISI 316. However, little work has been directed towards low temperature plasma surface alloying with both nitrogen and carbon simultaneously. In addition, little or no research has been conducted on the surface modification of medical grade austenitic stainless steels, such as ASTM F138 and F1586. In this study, plasma surface alloying treatments have been conducted on medical grade ASTM F138 and ASTM F1586 as well as on engineering grade AISI 316 for comparison. Systematic materials characterization was carried out using optical microscopy, GDOES and XRD. The surface properties such as hardness, wear and corrosion of the modified surface layers were evaluated. Based on the results, the response of these materials to simultaneous plasma surface alloying with both nitrogen and carbon is compared with nitriding and carburizing processes.     

Disinfecting action of a new multi-purpose disinfection solution for contact lenses.

The disinfection activity of a new multipurpose disinfection solution (OPTI-FREE Express with ALDOX) was compared to several other contact lens disinfecting solutions. The new solution is preserved with polyquaternium-1 and myristamidopropyl dimethylamine. The other solutions included 3% hydrogen peroxide systems and multipurpose solutions (MPS) preserved with polyhexamethylene biguanide. The products were tested for antimicrobial activity against Staphylococcus spp., Pseudomonas aeruginosa, Serratia marcescens, Candida albicans, Fusarium solani, and Aspergillus fumigatus. OPTI-FREE Express provided a broader range of antimicrobial activity than the MPS. It provided activity similar to that demonstrated by 3% hydrogen peroxide systems, but unlike the hydrogen peroxide system tested, it also prevented re growth of the organisms during extended storage.     

Thermal and Optical Properties of Yb3+- and Nd3+-Doped Phosphate Glasses Determined by Thermal Lens Technique

In this work, we study the thermal and optical properties of ion-doped phosphates glasses using the thermal lens (TL) technique. Three samples were characterized: Nd³⁺-doped Q-98; Nd³⁺-doped Q-100; and Yb³⁺-doped QX. We report multiwavelength TL measurements for a more accuracy determination of the fluorescence quantum efficiency and temperature coefficient of the optical path length change (ds/dT). In Nd-doped glasses, it was carried out using four discrete excitation wavelengths (between 514 and 872 nm) chosen to match with the ion absorption lines. In Yb-doped glass, the spectrum of heat generated along the Yb³⁺ transition (² F _5/2rarr² F _7/2) was obtained. In addition, parameters as thermal diffusivity and conductivity, thermal loading, etc were achieved. The advantages to obtain fluorescence quantum efficiency using the TL technique, mainly in Yb³⁺ doped materials, which are normally overestimated due to radiation trapping effect, are presented. The accuracy knowledge of these parameters is very important for design of high-power solid-state lasers, since these properties are directly related to the heat generation.     

Effects of feeding or abomasal infusion of canola oil in Holstein cows. 1. Nutrient digestion and milk composition

We determined the effects of feeding canola oil or infusing it into the abomasum on rumen fermentation, nutrient digestibility, duodenal flows of fatty acids, and milk composition in Holstein cows. Five ruminally and duodenally cannulated Holstein cows in late lactation were used in a 3 x 5 incomplete Latin square design. Treatments were 1) Control: basal diet (CON), 2) Control+supplementation of canola oil at 1 kg/d in the feed (FED), and 3) Control+abomasal infusion of canola oil at 1 kg/d (INF). Compared with CON, feed intake, ruminal fermentation characteristics, ruminal and total tract digestibilities of nutrients were not significantly affected by FED treatment but duodenal flows and milk concentrations of fatty acids (FA) such as trans-11 18:1 and cis-9 trans-11 18:2 (conjugated linoleic acid, CLA) were increased. In contrast to the effects of FED, INF reduced feed intake, total VFA production, intestinal flows of nutrients, FA digestibility and yields of milk and milk fat. Both FED and INF significantly reduced the proportions of saturated and medium-chain FA, and increased cis 18:1 in milk. Concentrations of 18:2n-6 and 18:3n-3 in milk were increased nearly 2-fold with INF relative to CON. Dietary or postruminal supplementation of canola oil to late-lactation cows reduced saturated FA and increased unsaturated C18 in milk but nutrient digestion was adversely affected with abomasal infusion of canola oil.     

Familial influences on gambling behavior: an analysis of 3359 twin pairs

BACKGROUND: Pathological gambling is becoming an increasing problem in the United States as the number of legalized gambling establishments grows. To examine vulnerability to pathological gambling, we estimated the familial contributions (i.e. inherited factors and/or experiences shared by twin siblings during childhood) to DSM-III-R pathological gambling symptoms and disorder. METHODS: Data were obtained from a telephone interview performed in 1991-92 utilizing the Diagnostic Interview Schedule Version III-Revised. Interviews were administered to 6718 members of the nationally distributed Vietnam Era Twin Registry of male-male monozygotic and dizygotic twin pairs who served in the military during the Vietnam era. RESULTS: Inherited factors explain between 35% (95% CI: 28%, 42%) and 54% (95% CI: 39%, 67%) of the liability for the five individual symptoms of pathological gambling behavior that could be estimated statistically. In addition, familial factors explain 56% (95% CI: 36%, 71%) of the report of three or more symptoms of pathological gambling and 62% (95% CI: 40%, 79%) of the diagnosis of pathological gambling disorder (four or more symptoms). CONCLUSIONS: Familial factors have an important influence on risk for pathological gambling behavior. The increasing access to legalized gambling is likely to result in a higher prevalence of pathological gambling behavior among individuals who are more vulnerable because of familial factors.     

Using health status surveys in medical consultations

The goal of this research was to identify patients' preferences for physician inquiry into various aspects of health status and to examine whether the preconsultation availability of health status data (collected from the SF-36 Health Status Questionnaire) influenced the physician's conduct during the consultation. Results from 58 prenatal patient visits yielded the following findings. First, patients expressed strong preferences for physicians to ask about the patient's perceptions of health in general and about physical dimensions of health status such as pain, vitality, and role limitations due to physical functioning. Patients also were more satisfied when doctors were perceived as having asked about these issues. Second, patients varied considerably in their preferences for physician inquiries into psychosocial issues such as social functioning, mental health, and role limitations due to emotional problems. Approximately half the patients wanted these matters discussed, whereas the remainder either did not care or preferred that doctors not ask about these topics. Third, the preconsultation availability of health status information had little effect on the degree to which physicians asked about the patient's health-related quality of life. Clinical implications are discussed.