Thermodynamic Parameters of the Uncatalyzed Redox Reaction Between Potassium Peroxydisulphate and D(+)Glucose

The uncatalyzed redox reaction between potassium peroxydisulphate and D(+) glucose was  studied titremetically . The progress of the reaction was followed by examining the concentration of potassium peroxydisulphate in the reaction mixture at different time intervals by iodometric titration method. Thermodynamic parameters, activation energy (Ea), frequency factor (A), entropy change (?S) and the free energy change (?G) of the uncatalyzed redox reaction were evaluated from the values of the fractional order rate constants ko at different temperatures. Keywords: Uncatalyzed redox reaction, thermodynamic parameters, D(+)glucose, Potassium peroxydisulphate

NORMAL VASCULAR REACTIVITY IS RESTORED BY APIGENIN IN DIABETIC RATS

Objective: Diabetes is a disease whose complications have serious implications for the health of sufferers; one of the most serious such complications is the deterioration of vascular reactivity. Apigenin is a natural flavonoid with PKC inhibiting and antioxidant properties. In this study, the impact of apigenin on vascular reactivity deterioration was investigated.Methods: Insulin resistance (IR) and insulin deficiency (ID) were induced by fructose and streptozotocin respectively. The isolated aortae vasoconstriction response to phenylephrine (PE) and potassium chloride (KCl) in addition to the vasodilation response to acetylcholine (ACh) and sodium nitroprusside (SNP) were tested.Results: IR and ID were associated with significantly exaggerated vasoconstriction to KCl and PE while significantly impaired vasodilation to ACh. Response to SNP was not significantly affected by both IR and ID. In vitro incubation with apigenin (7 7µM) for 20 min restored normal responses to PE, KCl and ACh in aortae isolated from insulin-resistant or insulin-deficient rats. Incubation for one hour with the PKC stimulant, phorbol 12-myristate 13-acetate (PMA, 800 nM) resulted in aortic impairment similar to that seen in aortae isolated from IR and ID animals. Incubation with both apigenin prevented PMA-induced exaggerated vasoconstriction response to both PE and KCl.Conclusion: Apigenin alleviates vascular exaggerated vasoconstriction and impaired dilation associated with diabetes or PKC activated

Nanocrystalline Na0.1V2O5.nH2Oxerogel Thin Film for Gas Sensing

Nanocrystalline thin film of Na0.1V2O5.nH2O xerogel obtained by sol-gel synthesis was used as a gas sensor. Gas sensing properties of different gases such as hydrogen, petroleum and humidity were investigated. Applying XRD and TEM the size of the nanocrystals is found to be 7.5 nm. SEM shows a highly porous structure with submicron meter-sized voids present throughout the sample. FTIR measurement shows different chemical groups identifying the obtained series of gels. The sample was n-type semiconductor according to the thermoelectric power and electrical conductivity. It can be seen that the sensor response curves from 130°C to 150°C show a rapid increase in sensitivity for all types of gas injection, low response values for heating period and the rapid high response values for cooling period. This result may suggest that this material is able to act as gas sensor during the heating and cooling process

Nanocrystalline Na0.1V2O5.nH2Oxerogel Thin Film for Gas Sensing

Nanocrystalline thin film of Na0.1V2O5.nH2O xerogel obtained by sol-gel synthesis was used as a gas sensor. Gas sensing properties of different gases such as hydrogen, petroleum and humidity were investigated. Applying XRD and TEM the size of the nanocrystals is found to be 7.5 nm. SEM shows a highly porous structure with submicron meter-sized voids present throughout the sample. FTIR measurement shows different chemical groups identifying the obtained series of gels. The sample was n-type semiconductor according to the thermoelectric power and electrical conductivity. It can be seen that the sensor response curves from 130°C to 150°C show a rapid increase in sensitivity for all types of gas injection, low response values for heating period and the rapid high response values for cooling period. This result may suggest that this material is able to act as gas sensor during the heating and cooling process