An extensive study of sol systems produced by the reduction of solvated Pd by Sn2+ is presented. We show that the reaction is initiated by the formation of a polynuclear Sn‐Pd complex, which is autoreductive, yielding sol particles of a Sn‐Pd alloy core with a stabilizing layer of Sn2+ ions. The role of the Sn2+ stabilizing layer in controlling particle size is discussed in detail. We apply the knowledge of these systems to understand similar processes occurring in commercial Pd sol systems used for sensitizing insulating surfaces for electroless plating. The chemistry of the sensitizing layer generated by these systems has also been studied. The sol sedimentation rate has been studied by centrifugation. Most of the investigation has been carried out via Mössbauer spectroscopy; precise isomer shift parameters for a number of Sn‐Pd compounds are reported.

Mössbauer spectroscopy has been used to study tin(II) sensitizer deposits formed on Kapton films (du Pont polyimide) for use in the recently reported photoselective metal deposition (PSMD) process. Combined with previous results, this work shows that the sensitizer is present as a colloid in the sensitizing bath and is adsorbed on the substrate when it is dipped. This activation mechanism would be expected to apply to other insulating substrates as well. The photosensitive substance contains more tetravalent tin than divalent. The divalent tin is oxidized by exposure either to air or to the Pd activation bath. The photosensitive compound is not any well recognized tin oxychloride or hydroxide.

The effects of variations in temperature within the physiologic range on minimal inhibitory concentrations (MICs) and on the serum bactericidal activity of 17 different antimicrobial agents for 432 strains of bacteria were studied. Comparison of 3,053 experimental MICs performed at 41.5, 40, 38.5, 37, or 35 C with duplicate standard MICs performed at 35 C showed a progressive increase in antimicrobial activity as the temperature was raised within the experimental range. At the highest temperature (41.5 C), 17.1% of MICs were four or more times lower, 7% were eight or more times lower, and 2% were greater than or equal to 16 times lower than the standard MICs performed at 35 C. Binding to proteins in serum neither accentuated nor diminished the augmenting effect of temperature on antimicrobial activity. Comparison of serum bactericidal activity determined at 35 C and 40 C revealed similar hyperthermic augmentation of antimicrobial activity.

For many years, stannous chloride solutions have been used to prepare surfaces so that they would catalyze deposition from electroless plating solutions. This paper discusses the colloid and solution chemistry of such baths, including the colloid formation, size mediation, and aging processes. The colloid is shown to be nucleated by stannic ions, and mediated by stannous ions. The investigation was carried out primarily using Mössbauer spectroscopy to characterize the materials involved.

The physics, chemistry, and possible applications of the storage of hydrogen in intermetallic reservoirs are discussed. Storage in the form of intermetallic hydrides can be safe and, where hydrogen has some special value as a fuel, economical. New pumps and refrigerators based on the heat of sorption of the hydrogen into the intermetallic are approaching commercial viability.

Background: Current standard chemotherapy protocols for lymphoma in cats carry risks of gastrointestinal toxicity, which can decrease quality of life and complicate response assessment. Protocols with less gastrointestinal toxicity may improve treatment tolerance.Hypothesis/Objectives: The study purpose was to compare response rate, outcome, and toxicity between cats that received vincristine or vinblastine as part of combination chemotherapy for lymphoma. We hypothesized that vinblastine would have similar efficacy, but less gastrointestinal toxicity, compared with vincristine.Animals: Forty client-owned cats with confirmed diagnosis of lymphoma. Methods: Cats were randomized to 1 of 2 treatment arms and received weekly COP-based chemotherapy for 6 months or until disease progression. Response rate, progression-free survival (PFS), lymphoma-specific survival (LSS), and incidence and severity of gastrointestinal and hematologic toxicity were compared between arms. Arm cross-over occurred if specific gastrointestinal toxicity criteria were noted.Results: Cats in both arms had similar response rates, PFS, and LSS (48 versus 64 days, P = .87; 139 versus 136 days, P = .96). Cats that received vincristine were significantly more likely to switch arms based on gastrointestinal toxicity than cats that received vinblastine (44.4 versus 10.5%, P = .02). Lower baseline weight was significantly negatively associated with PFS and LSS (P = .01, P = .003, respectively). Baseline anemia was significantly negatively associated with LSS (P = .04).Conclusions and Clinical Importance: Results suggest that vinblastine is a reasonable alternative to vincristine in the treatment of some cats with lymphoma. Baseline body weight remains a significant prognostic factor for cats with lymphoma.

The adsorption of acridine orange by H-, Na-, Mg-, Al-and Cu-montmorillonite has been studied by visible and infrared spectroscopy and by X-ray diffraction methods. Adsorption of the dye takes place by the mechanism of cation exchange. The maximum amount of adsorbed dye depends on the exchangeable metallic cation, decreasing in the order Na > H > Cu > Mg > Al. The adsorbed cationic dye is located in the interlayer space. Adsorption leads to metachromasy of the dye molecule and a shift of the absorption bands to lower wavelengths in the visible range. Two types of associations are formed between montmorillonite and acridine orange: (i) a monolayer of the dye situated in the interlayer space, with the aromatic rings parallel to the aluminosilicate layer and (ii) a bilayer in the interlayer space or tilting of the cationic dye relative to the aluminosilicate layer. In the association of type (i) metachromasy cannot be attributed to polymerization of the organic dye but must be caused by interactions between the oxygen plane of the aluminosilicate and the aromatic dye.

No abstract