Photocatalytic removal of selenite and selenate species: effect of EDTA and other process variables.

TiO2-assisted photocatalysis was employed for the removal of aqueous phase selenite and selenate species in conjunction with EDTA as a hole (h+) scavenger. Findings from the binary selenite/EDTA and selenate/EDTA systems showed high selenite and selenate removal at pH 4 and pH 6, with faster removal kinetics noted for the selenite species compared with the selenate species that showed a gradual change over the reaction course. The noted removal of selenite and selenate was attributed to their reduction by the conduction band electrons (e-). The effect of pH studies indicated high selenite, selenate, and EDTA removal in the acidic pH range, with the following specific trend: pH 4 > pH 6 > pH 12. Different from the EDTA studies, the use of thiocyanate alone did not initiate reduction of selenium oxyanions, and hence, its role as a hole scavenger in the present systems was not evident. However, the addition of EDTA to respective selenite/selenate/thiocyanate system at pH 4 did yield near complete removal of selenite and selenate species. The marginal role of thiocyanate as a hole scavenger was attributed to its negligible adsorption onto TiO2 surface. Furthermore, at pH 4 and within 3 h reaction time, enhanced selenate removal was noted with an increase in its initial concentration from 20 to 100 ppm, with near complete selenate removal noted for both cases. In general, findings from the present work indicate that both selenite and selenate can be successfully removed from the aqueous phase employing the TiO2-mediated photocatalysis and h(+)-scavenging agent EDTA.

Impact of GDP, spending on R&D, number of universities and scientific journals on research publications in pharmacological sciences in Middle East.

OBJECTIVES: Research in pharmacological science is vital to support the health needs of human beings. Measuring the research output provides information that forms the basis of strategic decisions. This study aimed to investigate the impact of Gross Domestic Product (GDP), spending on Research and Development (R&D), number of universities and scientific journals on research documents (papers), citable documents, citations per document and H-index in pharmacological science among Middle East countries. MATERIALS AND METHODS: All the 16 Middle East countries were included in the study. The information regarding GDP, spending on R&D, total number of universities and indexed scientific journals were collected. We recorded the total number of research documents, citable documents, citations per document and H-index in pharmacological science during the period 1996-2011. The main sources for information were World Bank, Web of Science, Journal Citation Reports (Thomson Reuters) and SCI-mago/Scopus. RESULTS: The mean per capita GDP of all the Middle East countries is 18125.49±5386.28 US$, spending on R&D 0.63±0.28% of GDP in US$, number of universities 36.56±11.33 and mean ISI indexed journal are 8.25±3.93. The number of research documents published in pharmacological science among the Middle East countries during the period 1996-2011 is 1344.44±499.34; citable documents 1286.37±476.34; citations per document 7.62± 0.84; and H-index is 30.68±6.32. There was a positive correlation between spending on R&D and citations per documents (r = 0.56, p = 0.02), H-Index (r = 0.56, p = 0.02); number of universities and research documents (r = 0.72, p = 0.002), citable documents (r = 0.72, p = 0.001); ISI indexed journals and research documents (r = 0.88, p = 0.0001), citable documents (r = 0.88, p = 0.0001), H-Index (r = 0.67, p = 0.004). However, there was no correlation between the GDP per capita and research outcome in pharmacological science. CONCLUSIONS: There is a positive association between spending on R&D, number of universities and indexed scientific journals on research outcome in pharmacological science in Middle East.

NH4+-NH3 removal from simulated wastewater using UV-TiO2 photocatalysis: effect of co-pollutants and pH.

The main objective of the present study was to investigate the efficiency of titanium dioxide (TiO2) assisted photocatalytic degradation (PCD) process for the removal of ammonium-ammonia (NH4(+)-NH3) from the aqueous phase and in the presence of co-pollutants thiosulfate (S2O3(2-)) and p-cresol (C6H4CH3OH) under varying mixed conditions. For the NH4(+)-NH3 only PCD experiments, results showed higher NH4 -NH3 removal at pH 12 compared to pH 7 and 10. For the binary NH4(+)-NH3/S2O3(2-) studies the respective results indicated a significant lowering in NH4(+)-NH3 PCD in the presence of S2O32- at pH 7/12 whereas at pH 10 a marked increase in NH4(+)-NH3 removal transpired. A similar trend was noted for the p-cresol/NH4(+)-NH3 binary system. Comparing findings from the binary (NH4(+)-NH3/S2O3(2-) and p-cresol/NH4(+)-NH3) and tertiary (NH4(+)-NH3/S2O3(2-)/p-cresol) systems, at pH 10, showed fastest NH4(+)-NH3 removal transpiring for the tertiary system as compared to the binary systems, whereas both the binary systems indicated comparable NH4(+)-NH3 removal trends. The respective details have been discussed.

Enhanced photocatalytic activity of nafion-coated TiO2.

Photocatalytic degradation (PCD) of aqueous paraquat was accelerated by the addition of either phosphate or sulfate salt. Attachment of these anions to the TiO2 surface possibly results in increased adsorption of the cationic paraquat species and in turn its photocatalysis rate. The same effect was obtained more consistently using the Nafion (an anionic polymer)-coated TiO2. Enhanced PCD of paraquat and some amine compounds was noted. However the anionic and neutral compounds were not affected significantly. Nafion proved to be stable against photocatalysis. It has been suggested that the degradation rate is larger for the cationic compounds with higher pK(B). For a phenol-paraquat-TiO2 system, paraquat degradation did not begin till near-complete phenol removal. Using the Nafion-coated TiO2, both phenol and paraquat degradations started simultaneously. Nevertheless, complete paraquat removal still took longer than phenol.

Subcellular localization of dystrophin and vinculin in cardiac muscle fibers and fibers of the conduction system of the chicken ventricle.

The subcellular localization of dystrophin and vinculin was investigated in cardiac muscle fibers and fibers of the conduction system of the chicken ventricle by immunofluorescence confocal microscopy. In ventricular cardiac muscle fibers, strong staining with antibody against dystrophin appeared as regularly arranged transverse striations at the sarcolemmal surface, and faint but uniform staining was seen in narrow strips between these striations. In fibers of the ventricular conduction system, the sarcolemma was stained uniformly with this antibody, but strong staining was found as regular striations in many areas and as scattered patches in other areas of the sarcolemma. These intensely stained striations and scattered patches of dystrophin were colocalized with those of vinculin. Because dystrophin striations were located at the level of Z bands of the underlying myofibrils, they were regarded as the concentration of this protein at costameres together with vinculin. In fibers of the conduction system, myofibrils were close to the sarcolemma where dystrophin and vinculin assumed a striated pattern, at some distance from the cell membrane where these proteins exhibited a patchy distribution, and distant from the sarcolemma where dystrophin was uniformly distributed. These data suggest that the distribution patterns of dystrophin reflect the degree of association between the sarcolemma and underlying myofibrils.