ABSTRACT
Morphology is a critical parameter for various thin film applications, influencing properties like wetting, catalytic performance and sensing efficiency. In this work, we report on the impact of oxygen partial flow on the morphology of ceramic thin films deposited by pulsed DC reactive magnetron sputtering. The influence of O2/Ar ratio was studied on three different model systems, namely Al2O3, CuO and TiO2. The availability of oxygen during reactive sputtering is a key parameter for a versatile tailoring of thin film morphology over a broad range of nanostructures. TiO2 thin films with high photocatalytic performance (up to 95% conversion in 7 h) were prepared, exhibiting a network of nanoscopic cracks between columnar anatase structures. In contrast, amorphous thin films without such crack networks and with high resiliency to crystallization even up to 950 °C were obtained for Al2O3. Finally, we report on CuO thin films with well aligned crystalline nanocolumns and outstanding gas sensing performance for volatile organic compounds as well as hydrogen gas, showing gas responses up to 35% and fast response in the range of a few seconds.
ABSTRACT
Starting with lead compound 2, we sought to increase the selectivity for alpha(v)beta(3)-mediated cell adhesion by examining the effects of structural changes in both the guanidine mimetic and the substituent alpha to the carboxylate. To prepare some of the desired aminoimidazoles, a novel reductive amination utilizing a trityl-protected aminoimidazole was developed. It was found that guanidine mimetics with a wide range of pK(a)'s were potent antagonists of alpha(v)beta(3). In general, it appeared that an acylated 2-aminoimidazole guanidine mimetic imparted excellent selectivity for alpha(v)beta(3)-mediated adhesion versus alpha(IIb)beta(3)-mediated platelet aggregation, with selectivity of approximately 3 orders of magnitude observed for compounds 3g and 3h. It was also found in this series that the alpha-substituent was required for potent activity and that 2,6-disubstituted arylsulfonamides were optimal. In addition, the selective alpha(v)beta(3) antagonist 3h was found to be a potent inhibitor of alpha(v)beta(3)-mediated cell migration.
Subject(s)
Isoxazoles/chemical synthesis , Receptors, Vitronectin/antagonists & inhibitors , beta-Alanine/analogs & derivatives , Cell Adhesion/drug effects , Cell Movement/drug effects , Chemotaxis/drug effects , Guanidines/chemistry , Humans , Hyperplasia/metabolism , In Vitro Techniques , Isoxazoles/chemistry , Isoxazoles/pharmacology , Kidney/cytology , Kidney/drug effects , Kidney/metabolism , Platelet Aggregation/drug effects , Receptors, Vitronectin/biosynthesis , Stereoisomerism , Structure-Activity Relationship , Tumor Cells, Cultured , Vitronectin/pharmacology , beta-Alanine/chemical synthesis , beta-Alanine/chemistry , beta-Alanine/pharmacologyABSTRACT
A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servicing. The number of refrigerant exposures of service technicians was estimated to be 135,000 per year. Exposures of vehicle occupants can occur when refrigerant enters passenger compartments due to sudden leaks in air-conditioning systems, leaks following servicing, or leaks caused by collisions. The total number of exposures of vehicle occupants was estimated to be 3,600 per year. The largest number of exposures of vehicle occupants was estimated for leaks caused by collisions, and the second largest number of exposures was estimated for leaks following servicing. Estimates used in the fault tree analysis were based on a survey of automotive air-conditioning service shops, the best available data from the literature, and the engineering judgement of the authors and expert reviewers from the Society of Automotive Engineers Interior Climate Control Standards Committee. Exposure concentrations and durations were estimated and compared with toxicity data for refrigerants currently used in automotive air conditioners. Uncertainty was high for the estimated numbers of exposures, exposure concentrations, and exposure durations. Uncertainty could be reduced in the future by conducting more extensive surveys, measurements of refrigerant concentrations, and exposure monitoring. Nevertheless, the analysis indicated that the risk of exposure of service technicians and vehicle occupants is significant, and it is recommended that no refrigerant that is substantially more toxic than currently available substitutes be accepted for use in vehicle air-conditioning systems, absent a means of mitigating exposure.
Subject(s)
Air Conditioning/adverse effects , Automobiles , Environmental Exposure , Humans , Occupational Exposure , Risk Assessment , United States , United States Environmental Protection AgencyABSTRACT
The structure-activity relationships of some tetracyclic heterocycles related to Brequinar were explored. Activities as inhibitors of dihydroorotate dehydrogenase and the mixed lymphocyte reaction are related to ring system, heteroatom placement, and pendant ring substitution.
Subject(s)
Biphenyl Compounds/chemistry , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/pharmacology , Immunosuppressive Agents/chemistry , Immunosuppressive Agents/pharmacology , Oxidoreductases Acting on CH-CH Group Donors , Dihydroorotate Dehydrogenase , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Humans , Lymphocyte Culture Test, Mixed , Oxidoreductases/antagonists & inhibitors , Structure-Activity RelationshipABSTRACT
The discovery of terphenyl derivatives as highly selective COX-2 inhibitors resulted from our efforts to overcome poor pharmacokinetics demonstrated by the COX-2 selective diarylthiophene DuP 697 [2-bromo-4-(4'-sulfonylmethyl)phenyl-5-(4'-fluoro)phenylthiophe ne]. Detailed SAR related to the ortho-biphenyls and variants of the central ring are described herein.