Differential responses to blood pressure and oxidative stress in streptozotocin-induced diabetic wistar-kyoto rats and spontaneously hypertensive rats: effects of antioxidant (honey) treatment

Oxidative stress is implicated in the pathogenesis and/or complications of hypertension and/or diabetes mellitus. A combination of these disorders increases the risk of developing cardiovascular events. This study investigated the effects of streptozotocin (60 mg/kg; ip)-induced diabetes on blood pressure, oxidative stress and effects of honey on these parameters in the kidneys of streptozotocin-induced diabetic Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Diabetic WKY and SHR were randomized into four groups and received distilled water (0.5 mL) and honey (1.0 g/kg) orally once daily for three weeks. Control SHR had reduced malondialdehyde (MDA) and increased systolic blood pressure (SBP), catalase (CAT) activity, and total antioxidant status (TAS). SBP, activities of glutathione peroxidase (GPx) and glutathione reductase (GR) were elevated while TAS was reduced in diabetic WKY. In contrast, SBP, TAS, activities of GPx and GR were reduced in diabetic SHR. Antioxidant (honey) treatment further reduced SBP in diabetic SHR but not in diabetic WKY. It also increased TAS, GSH, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, activities of GPx and GR in diabetic SHR. These data suggest that differences in types, severity, and complications of diseases as well as strains may influence responses to blood pressure and oxidative stress.     

Effects of thermal annealing on the optical,spectroscopic, and structural properties of tris (8-hydroxyquinolinate) gallium films grown on quartz substrates

In this study we report the optical, spectroscopic, and structural properties of vacuum deposited tris (8-hydroxyquinolinate) gallium film upon thermal annealing in the temperature range from 85 °C to 255 °C under a flowing nitrogen gas for 10 min. The optical UV–vis–NIR and luminescence spectroscopy measurements were performed to estimate the absorption bands, optical energy gap (E_g), and photoluminescence (PL) of the films. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques were used to probe the spectroscopic and structural nature of the films. We show that, by annealing the films from 85 °C to 235 °C, it is possible to achieve an enhanced absorption and increased photoluminescence to five times stronger than that of the pristine film. The PL quenching at 255 °C was attributed to the presence of plainer chains allow easy going for excitons to a long distance due to the crystalline region formation of α-Gaq3 polymorph. The reduction in E_g and infrared absorption bands upon annealing were referred to the enhancement in π–π interchain interaction and conformational changes by re-arrangement of the Gaq3 quinolinate ligands, respectively. Stokes shift for the films were observed and calculated. From the differential scanning calorimetry, DSC measurements, higher glass transition temperature was observed for Gaq3 (T_g = 182 °C) compared to that of Alq3 (T_g = 173 °C), which suggests the existence of stronger dipolar interaction in Gaq3 due to the Ga³⁺ cation effect, in comparison to that of Alq3.     

The effect of substitution of zinc with aluminium in the brucite-like layers on the physicochemical properties of zinc-aluminium-layered double hydroxide-pamoate nanocomposite

Layered organic–inorganic hybrid materials of Zn-Al-layered double hydroxide (LDH)-pamoate nanocomposite (ZAPR) were prepared using various initial Zn/Al molar ratios (R_i) from 8:1 to 2:1 which gave initial values of A³⁺/(Zn²⁺ + Al³⁺) mole fractions, (x_i) from 0.11 to 0.33. The Al³⁺ mole fractions in the resulting nanocomposite material (x_f) were greater than x_i and the difference between x_i and x_f was found to be a constant value of 0.03. The increase in the x_f values will increase the Al³⁺ content in the interlayer spaces of layered double hydroxide and therefore increases the charge density of the inorganic brucite-like layers and give stronger electrostatic attraction between the excess positive charge of Al³⁺ and the negative charge of the interlayer pamoate anion and hence decreases the d value of the material. However, the BET surface area of the resulting materials will decreases when the x_f is increased. This shows that the mole fraction of Zn²⁺ replaced by Al³⁺ in the inorganic brucite-like layer plays an important role in controlling the physicochemical properties of the resulting material, which is particularly useful in determining tailor-made property required in the designed material.     

Continuous adsorption of lead ions in a column packed with palm shell activated carbon

The continuous adsorption of lead ions from aqueous solution on commercial, granular, unpretreated palm shell activated carbon (PSAC) was studied. Effect of pH, flow rates and presence of complexing agents (malonic and boric acids) were examined. The breakthrough period was longer at pH 5 indicating higher adsorption capacity of lead ions at higher pH. Increase of the flow rate, expectedly, resulted in the faster saturation of the carbon bed. Presence of complexing agents did not improve adsorption uptake of lead ions. However, presence of malonic acid resulted in smoother pH stabilization of solution compared to single lead and lead with boric acid systems. The results on continuous adsorption of lead were applied to the model proposed by Wang et al. [Y.-H. Wang, S.-H. Lin, R.-S. Juang, Removal of heavy metals ions from aqueous solutions using various low-cost adsorbents, J. Hazard. Mater. B 102 (2003) 291–302]. The agreement between experimental and modelled breakthrough curves was satisfactory at both pHs.     

Syngas (H2/CO) in a spark-ignition direct-injection engine. Part 1: Combustion,performance and emissions comparison with CNG

The combustion, performance, and emissions of syngas (H₂/CO) in a four-stroke, direct-injection, spark-ignition engine were experimentally investigated. The engine was operated at various speeds, ranging from 1500 to 2400 rev/min, with the throttle being held in the wide-open position. The start of fuel injection was fixed at 180° before the top dead center, and the ignition advance was set at the maximal brake torque. The air/fuel ratio was varied from the technically possible lowest excess air ratio (λ) to lean operation limits. The results indicated that a wider air/fuel operating ratio is possible with syngas with a very low coefficient of variation. The syngas produced a higher in-cylinder peak pressure and heat-release rate peak and faster combustion than for CNG. However, CNG produced a higher brake thermal efficiency (BTE) and lower brake specific fuel consumption (BSFC). The BTE and BSFC of the syngas were on par to those of CNG at higher speeds. For the syngas, the total hydrocarbon emission was negligible at all load conditions, and the carbon monoxide emission was negligible at higher loads and increased under lower load conditions. However, the emission of nitrogen oxides was higher at higher loads with syngas.     

Radiation exposure during travelling in Malaysia

Absorbed dose rates in vehicles during travelling by different modes of transport in Malaysia were measured. Radiation levels measured on roads in Peninsular Malaysia were within a broad range, i.e. between 36 and 1560 nGy h(-1). The highest reading, recorded while travelling near monazite and zircon mineral dumps, was 13 times the mean environmental radiation level of Malaysia. It is evident that radioactive material dumps on the roadsides can influence the radiation level on the road. The absorbed dose rates measured while travelling on an ordinary train were between 60 and 350 nGy h(-1). The highest reading was measured when the train passed a tunnel built through a granite rock hill. The measurement during sea travelling by ferries gave the lowest radiation level owing to merely cosmic radiation at the sea level.     

Old oil palm trunk: A promising source of sugars for bioethanol production

Oil palm trees are replanted at an interval of approximately 25 years because of decreased oil productivity of old trees. Consequently the felled trunks are the enormous amount of biomass resources in the palm oil producing countries such as Malaysia and Indonesia. In this report, we found that the felled oil palm trunk contains large quantity of sap, which accounts for approximately 70% of the whole trunk weight, and that sugars existing in the sap increased remarkably during storage after logging. Total sugar in the sap increased from 83 mg ml^?1 to 153 mg ml^?1, the concentration comparable to that of sugar cane juice, after 30 days of storage, followed by the gradual decrease. The sugars contained in the sap were glucose, sucrose, fructose and galactose, all of which are fermentable by ordinary industrial yeast strains. The results indicate that old oil palm trunk becomes a promising source of sugars by proper aging after logging and, thus, its sap can be a good feedstock for bioethanol.     

Influencing factors of water electrolysis electrical efficiency

As a promising method of hydrogen production by utilizing renewable energy sources for future, water electrolysis is one of the favorite fields of the study and scientific experiment for many researchers all around the world. One of the most popular related research areas is the efficiency enhancement of the process by the means of reducing the electric power consumption in electrolysers. Regarding to different effective factors related to this issue, many efforts have been done to reach elevated levels of current densities by maintaining or even reducing the electrolysis cell voltage. According to this matter, recommendations could be given for reaching higher process efficiencies. This paper analyzes the factors with an influence on water electrolysis efficiency by studying available verified information in the electrical, electrochemical, chemical, thermodynamics and fluid mechanics fields.