The information obtained from the characterization of vanadium oxide single crystal surfaces is related to the study of vanadia nanoparticles supported on silica and alumina thin films, model systems for the so-called ‘‘supported monolayer vanadia catalysts’’. It is found that these particles have properties similar to V2O3 surfaces, where the topmost V ions are involved in vanadyl groups and h...

The preparation of vanadyl pyrophosphate (VPO) strongly influences their catalytic activity in partial oxidation of butane to maleic anhydride. The characteristics of VOHPO4•0.5H2O, (called “the precursor” in this paper) are strongly influenced by the reagents, the ratio of phosphorous to vanadium, the nature of the solvent and the conditions of the reduction step during the preparation. Synhes...

Acult mallard ducks fed 0, 1, 10, or 100 ppm vanadyl sulfate in the diet were sacrificed after 12 wk on treatment; tissues were analyzed for vanadium. No birds died during the study and body weights did not change. Vanadium accumulated to higher concentrations in the bone and liver than in other tissues. Concentrations in bones of hens were five times those in bones of drakes, suggesting an int...

Mice fed a diet low in many trace elements and raised in an environment where contamination from extraneous trace ele ments was controlled were given small amounts (5 jig/ml) of arsenite, germanate, stannous, or vanadyl ions in drinking water for their life times. Animals receiving arsenite had a significantly decreased incidence of all tumors, and of tumors of the lung, compared to those recei...

In the 21st century, patients suffering from diabetes mellitus (DM), a lifestyle-related disease, will increase more than in the 20th century. DM is threatening because of the development of many severe secondary complications, including atherosclerosis, microangiopathy, renal dysfunction and failure, cardiac abnormalities, diabetic retinopathy, and ocular disorders. Generally, DM is classified...

V2O5/SiO2 nanoparticles was prepared via an one-pot sol gel method from vanadyl- acetylacetonate and tetraethylorthosilicate in refluxing MeOH, followed by calcination at 700 °C for 2 hours. The resultant nanoparticles was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), TGA and FTIR techniques. Rapid and efficient ar...

sybil attacks pose a serious threat for wireless sensor networks (wsn) security. they can create problems in routing, voting schemes, decision making, distributed storage and sensor re-programming. in a sybil attack,the attacker masquerades as multiple sensor identities, that are actually controlled by one or a few existing attacker nodes. sybil identities are fabricated out of stolen keys, obt...

in this study, a specific ch4 sensor is fabricated based on interdigitated electrode that modified with core-shell of tungsten carbide/tin oxide (wc/sno2) nanoparticles by wet chemical method in different percents of carbon and tungsten. the morphology of wet chemical-synthesized wc/sno2 core-shell was evaluated by different methods such as patterned x-ray diffraction (xrd), and particle size a...

urease was immobilized on platinum electrode both by chemical binding and electropolymerization.the conductometric urea biosensor thus prepared showed a detection limit of 4.9×10-5 m and linear dynamic range from 4.9×10-5 to 5.8×10-3 m for urea concentration when the enzyme is covalently immobilized on pt electrodes. conductometric transducers respond to the changes in ionic strength thereby le...