Sol-Gel Synthesis of Lithium Aluminate

LiAlO₂ was prepared by two sol-gel methods using simultaneous hydrolysis of the reagents: aluminum sec -butoxide/ lithium methoxide and aluminum sec -butoxide/LiOH. The resulting ceramic powders were compared with those prepared by two conventional methods (i.e., solid-state fusion and peroxide). The sol-gel method provided powders with a very high γ-LiAlO₂ content after calcining at temperatures as low as 700°C when LiOH was used. The solids were characterized by AAS, DTA, TGA, XRD, and SEM.     

Normal regional anatomy of the shoulder

Transitional cell carcinoma of the bladder is associated with a high relapse rate, locally and systemically, particularly in patients with nodal or soft-tissue involvement, despite radical cystectomy. The responsiveness of the disease to chemotherapy in the metastatic setting has stimulated the use of systemic therapy in earlier stage disease, either before (neoadjuvant) or after (adjuvant) definitive local therapy. Interpretation of the data is hampered by low patient accrual to randomized trials, lack of standardization of local treatment modalities, and the use of a variety of chemotherapy agents and regimens pointing to the difficulty in reaching a consensus as to what constitutes standard therapy. In this article, we review the use of adjuvant and neoadjuvant chemotherapy, the advantages and disadvantages of both approaches, and the recommendations that can be made based on available data. New approaches to improving survival, potentially with organ preservation, include the development of more effective chemotherapy, and the identification of prognostic features-clinical or biologic-that might be a better guide to patient selection.     

Model updating improves MRAC performance

The performance of an MRAC design can be improved by using the model-updating concept, which places the state of the system into the reference model at regular time intervals. This paper discusses criteria for determining this updating and a proof is given to show that model updating does not influence the stability properties of an MRAC design. A typical example indicates an improvement in the control performance obtained by the application of model updating.     

The high-temperature effective work function of chemically vapor deposited rhenium on a polycrystalline molybdenum substrate

The work function of chemically vapor deposited rhenium, with a (0001) preferred orientation, on a molybdenum substrate was determined using the thermionic emission method. Data were collected as a function of time and temperature on temperature ramps from 1800 to 2600 K in 100-K increments. The effect of pressure on effective work function was demonstrated by introducing oxygen, nitrogen, and carbon dioxide through a precision leak valve into the vacuum emission vehicle. The effect of introducing various gasses was negligible. Also, no significant time or temperature dependence was observed. The sample yielded the maximum average effective work function, 5.08 eV, at 2100 K. The overall average effective work function was determined to be 5.02 eV.     

Electrophysiological and Behavioral Responses of a Cuban Population of the Sweet Potato Weevil to its Sex Pheromone

The sex pheromone of feral sweet potato weevils Cylas formicarius elegantulus from Cuba was found, via solid-phase microextraction analysis, to be identical to (Z)-3-dodecenyl (E)-2-butenoate, a previously reported compound. Females emitted 20 pg pheromone d⁻¹. In scanning electron microscopy studies carried out on the male antenna, we identified several types of sensilla: sensilla trichoidea of type 1 (ST1) as long hairs (100–150 μm), sensilla trichoidea of type 2 as short hairs (50–60 μm), sensilla basiconica of type 1 as thick pegs (20–25 μm), sensilla basiconica of type 2 as curved pegs (10–15 μm), and sensilla basiconica of type 3 as thin and straight short pegs (15–20 μm). The same types were observed in female antennae but ST1 were far less abundant than in males. Sensilla chaetica were also found on the flagellum subsegments in both sexes. In electrophysiological tests, the crotonate function in the pheromone structure proved to be critical for activity since regular depolarizations (0.6–0.8 mV) were obtained with puffs on 1 μg of the attractant, but not with puffs of the formate, acetate, propionate, or butyrate analogue of the pheromone. In a double dual-choice olfactometer, males showed maximum activity between the 4th and the 8th hr of scotophase at a dose of 50–1000 ng of pheromone. In field tests, a correlation between the contents of the Z,E isomer in the pheromone formulation with activity was noticed, and baits containing this isomer of stereomeric purity >94% showed the highest attractivity. The presence of 5% of the Z,Z isomer in the lure did not induce any synergistic or inhibitory effect, and the alcohol precursor of the pheromone was inactive. The results show that use of a stereomerically pure pheromone may not be necessary in pest control strategies.     

New hydroxyapatite–hydrotalcite composites II. microwave irradiation effect on structure and texture

Acid-basic materials are often used to catalyse organic reactions. Hydroxyapatite is acidic and hydrotalcite presents basic properties. The association of both compounds in a single material should present a rather unique catalytic behavior. Three preparations of hydroxyapatite impregnated with hydrotalcite are presented. The effect of microwave irradiation, at different preparation levels, is discussed. A homogeneous distribution of hydrotalcite on hydroxyapatite surface is obtained when hydrotalcite is precipitated over a previously microwave irradiated hydroxyapatite. Instead, if the hydrotalcite mixture is incorporated to the hydroxyapatite precursor gel and the resulting mixture microwave irradiated, hydrotalcite is preferentially deposited in the hydroxyapatite interparticle spaces. When both hydroxyapatite and hydrotalcite solutions are irradiated, mixed and irradiated again, the composite behaves as the addition of the two components.     

BMS Derivatives C7-Linked to β-Cyclodextrin and Hyperbranched Polyglycerol Retain Activity against R5-HIV-1NLAD8 Isolates and Can Be Deemed Potential Microbicides

Amides from indole-3-glyoxylic acid and 4-benzoyl-2-methylpiperazine, which are related to entry inhibitors developed by Bristol-Myers Squibb (BMS), have been synthesized with aliphatic chains located at the C7 position of the indole ring. These spacers contain an azido group suitable for the well-known Cu(I)-catalyzed (3+2)-cycloaddition or an activated triple bond for the nucleophilic addition of thiols under physiological conditions. Reaction with polyols (β-cyclodextrin and hyperbranched polyglycerol) decorated with complementary click partners has afforded polyol-BMS-like conjugates that are not cytotoxic (TZM.bl cells) and retain the activity against R5-HIV-1_NLAD8 isolates. Thus, potential vaginal microbicides based on entry inhibitors, which can be called of 4^th generation, are reported here for the first time.