Characterization of Pt/SiO2 Model Catalysts at UHV and Near Atmospheric Pressures

Pt/SiO₂ model catalyst samples, prepared under UHV conditions in a contiguous high pressure reactor cell surface analysis chamber, have been characterized via CO oxidation reaction kinetics under elevated pressure conditions (approaching 1 atm). Reaction kinetics are studied as a function of Pt coverage (θ _Pt = 1–10 mL), along with measurements on a Pt(110) single crystal for direct comparison. CO desorption measurements and STM measurements on Pt/SiO₂ films at T = 300 K have been obtained at various θ _Pt. Kinetic results show agreement between observations on single crystal and catalyst samples, and general agreement and correlation is obtained for site calculations across the various methods. Results demonstrate the utility of well characterized model catalyst samples in obtaining qualitative and quantitative reactivity data at elevated pressures.     

Polymer nanocomposites based on transition metal ion modified organoclays

A unique class of nanocomposites containing organoclays modified with catalytically active transition metal ions (TMI) and ethylene vinyl acetate (EVA) copolymers was prepared. The morphology, thermal and rheological properties of these nanocomposites were studied by thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), extended X-ray absorption fine structure (EXAFS) spectroscopy, X-ray scattering/diffraction and oscillatory shear rheometry. TMI-modified organoclays were thought to possess pillaring of multivalent TMI in the interlayer silicate gallery, leading to a notable reduction of the interlayer d-spacing. The resulting nanocomposites exhibited significantly improved thermal stability and fire retardation properties, but similar morphology (i.e., an intercalated-exfoliated structure) and rheological properties comparable with EVA nanocomposites containing unmodified organoclays. It appears that the compressed organic component in the TMI-modified organoclay can still facilitate the intercalation/exfoliation processes of polymer molecules, especially under extensive shearing conditions. The improved fire retardation in nanocomposites with TMI-modified organoclays can be attributed to enhanced carbonaceous char formation during combustion, i.e., charring promoted by the presence of catalytically active TMI.     

Chemical characterization of the predominant proteins secreted by mouse seminal vesicles

Eosinophilic fasciitis is a disorder characterised by induration of the skin due to chronic inflammation and fibrosis of the subcutaneous septa and muscular fascia. It is different from sclerodermia. This is a clinical entity that presents as swelling, tenderness and stiffness of the extremities associated with peripheral eosinophilia. We described a patient with this disorder with 18 month of evolution who had a bilateral carpal tunnel syndrome. Her disease appeared after steroid treatment. A review of medical literature demonstrated that similar clinical pictures are originated by different causes. Some authors propose to encompass this group of disorder under the designation of "fasciitis-panniculitis syndrome" instead of "eosinophilic fasciitis" although the well-known eosinophilic fasciitis is clearly recognized and demonstrated.     

Dropping out of treatment: A critical review.

After a discussion of methodological issues, literature on dropping out of treatment is critically reviewed in 6 areas: hospital treatment of general psychiatric and tubercular patients, outpatient treatment of internal medical conditions, alcoholism, heroin addiction, general psychiatric outpatient psychotherapy, and double-blind drug studies. 15 factors were found to predict dropping out in 100%, 83-88%, and 60-75% of the relevant studies: (a) social isolation and/or unaffiliation, therapist attitudes and behavior, discrepancies between patient and therapist treatment expectations; (b) passive-aggressive behavior, family attitudes and behavior, motivation, behavioral and/or perceptual dependence, psychological mindedness and/or denial, symptom levels and symptom relief, socioeconomic status, sociopathic features, alcoholism and/or drug dependence; and (c) age, sex, and social stability. (101/2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)