A simple water iodizing system, which incorporates the Venturi principle in combination with the controlled release mechanism of a silicone-sodium iodide elastomer, for the iodization of rural piped-water supply in th...A simple water iodizing system, which incorporates the Venturi principle in combination with the controlled release mechanism of a silicone-sodium iodide elastomer, for the iodization of rural piped-water supply in the control of endemic iodine deficiency has been developed and its effectiveness evaluated in three Iban longhouse villages in the iodinedeficient district of Lubok Antu, Sarawak. Urines were collected for iodine assays from women aged 15-40 years before and at 6 and 12 months after the connection of the iodinating device; goiter assessment was performed on the women at the start and end of the 1-year study. Water samples were collected for iodine assays at 2-weekly intervals. In all three villages, significant and sustained increases in median urinary iodine excretions,reaching levels recommended for an iodine-suffcient population, were observed; goitre prevalences were reduced in all the villages (by 22.6% to 35.8%). The iodine levels in the water ranged from 34 μg/l to 212 μg/L. In the control village, median urinary iodine excretions remained essentially unchanged but a small increase in goiter prevalence was observed. The iodized water was well received by the villagers and no adverse effects of water iodization were observed. The system functioned unattended throughout the one year period. The cost of providing supplemental iodine via the iodizing device is approximately 60 cents (U.S.) per family per year which is affordable by either the Government or the villagers. It is concluded that the iodizing system offers a new cost-effective strategy for the control of endemic iodine deficiency in Sarawak and may have applications in other areas with similar water sources展开更多
The induction of biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Environmental stressors have been implicated in the induction of biofilm formation;however, it i...The induction of biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Environmental stressors have been implicated in the induction of biofilm formation;however, it is unclear whether all stressors, or a select few, are responsible. This study aimed to investigate the effects of three stressors, nitrogen depletion, reduced or elongated day lengths, and increased culture turbulence on bio-film formation of Parachlorella kessleri. We also examined corresponding effects on growth and production of reactive oxygen species. Turbulence induced the greatest response in which a significant decrease in growth plus an increase in superoxide production and flocculation efficiency were seen for the 300-rpm treatment. For varying day lengths, stress response was not observed, however, a significant increase in EPS secretion was measured in both shorter and longer days. Nitrogen depletion induced a low-level stress response, in which superoxide production increased for the highest concentrations, while growth was not impacted. In contrast to previous studies on nitrogen depletion, a significant increase in EPS secretion was not observed. Results indicate that stress response varies according to type and magnitude. EPS production and thus biofilm formation are not linked to the stress indicators investigated. P. kessleri uses small quantities of EPS to contribute to cell stickiness, but not necessarily to the full formation of a biofilm;however, cell stickiness served as a mechanism for substrate adherence and cellular aggregation none the less.展开更多
Although Ghana produces natural gas and has several gas reserves, the country still depends on supplies from neighbouring countries for power generation due to challenges like fuel suppl</span><span style=&qu...Although Ghana produces natural gas and has several gas reserves, the country still depends on supplies from neighbouring countries for power generation due to challenges like fuel suppl</span><span style="font-family:Verdana;">y</span><span style="font-family:Verdana;"> inefficiencies and increasing cost of gas production. Gas supply is thus a limiting factor for power generation. This study explores strategies to improve gas supplies for sustainable power generation in Ghana. The study examined the underlying factors inhibiting gas supplies in Ghana, investigated the risks in the gas supply industry, and explored strategies for improving gas supplies in Ghana. The study adopted an inductive approach that utilises both qualitative and quantitative research methods. With the use of questionnaires, data were collected from 151 respondents who were selected by purposive and snowball sampling procedures. The collected data were descriptively and inferentially analysed with analytical tools in the SPSS. The study</span><span style="font-family:Verdana;">’</span><span style="font-family:Verdana;">s findings conclude that factors that inhibit gas supply in Ghana include the lack of growth and supply investment in the gas supply industry, power sector debt on the gas market, and the lack of an extensive distribution infrastructure/network. Also, the gas industry in Ghana lacks the requisite investment drive which culminates into inefficiency and ultimately undermines efforts to achieve sustainable power generation. Politics influence in issues relating to gas supplies in Ghana inhibits long-term supply relationships and permanent infrastructure in gas supply, both locally and on the world market.展开更多
文摘A simple water iodizing system, which incorporates the Venturi principle in combination with the controlled release mechanism of a silicone-sodium iodide elastomer, for the iodization of rural piped-water supply in the control of endemic iodine deficiency has been developed and its effectiveness evaluated in three Iban longhouse villages in the iodinedeficient district of Lubok Antu, Sarawak. Urines were collected for iodine assays from women aged 15-40 years before and at 6 and 12 months after the connection of the iodinating device; goiter assessment was performed on the women at the start and end of the 1-year study. Water samples were collected for iodine assays at 2-weekly intervals. In all three villages, significant and sustained increases in median urinary iodine excretions,reaching levels recommended for an iodine-suffcient population, were observed; goitre prevalences were reduced in all the villages (by 22.6% to 35.8%). The iodine levels in the water ranged from 34 μg/l to 212 μg/L. In the control village, median urinary iodine excretions remained essentially unchanged but a small increase in goiter prevalence was observed. The iodized water was well received by the villagers and no adverse effects of water iodization were observed. The system functioned unattended throughout the one year period. The cost of providing supplemental iodine via the iodizing device is approximately 60 cents (U.S.) per family per year which is affordable by either the Government or the villagers. It is concluded that the iodizing system offers a new cost-effective strategy for the control of endemic iodine deficiency in Sarawak and may have applications in other areas with similar water sources
文摘The induction of biofilm formation has been explored as a means of harvesting microalgae for bioprocessing applications. Environmental stressors have been implicated in the induction of biofilm formation;however, it is unclear whether all stressors, or a select few, are responsible. This study aimed to investigate the effects of three stressors, nitrogen depletion, reduced or elongated day lengths, and increased culture turbulence on bio-film formation of Parachlorella kessleri. We also examined corresponding effects on growth and production of reactive oxygen species. Turbulence induced the greatest response in which a significant decrease in growth plus an increase in superoxide production and flocculation efficiency were seen for the 300-rpm treatment. For varying day lengths, stress response was not observed, however, a significant increase in EPS secretion was measured in both shorter and longer days. Nitrogen depletion induced a low-level stress response, in which superoxide production increased for the highest concentrations, while growth was not impacted. In contrast to previous studies on nitrogen depletion, a significant increase in EPS secretion was not observed. Results indicate that stress response varies according to type and magnitude. EPS production and thus biofilm formation are not linked to the stress indicators investigated. P. kessleri uses small quantities of EPS to contribute to cell stickiness, but not necessarily to the full formation of a biofilm;however, cell stickiness served as a mechanism for substrate adherence and cellular aggregation none the less.
文摘Although Ghana produces natural gas and has several gas reserves, the country still depends on supplies from neighbouring countries for power generation due to challenges like fuel suppl</span><span style="font-family:Verdana;">y</span><span style="font-family:Verdana;"> inefficiencies and increasing cost of gas production. Gas supply is thus a limiting factor for power generation. This study explores strategies to improve gas supplies for sustainable power generation in Ghana. The study examined the underlying factors inhibiting gas supplies in Ghana, investigated the risks in the gas supply industry, and explored strategies for improving gas supplies in Ghana. The study adopted an inductive approach that utilises both qualitative and quantitative research methods. With the use of questionnaires, data were collected from 151 respondents who were selected by purposive and snowball sampling procedures. The collected data were descriptively and inferentially analysed with analytical tools in the SPSS. The study</span><span style="font-family:Verdana;">’</span><span style="font-family:Verdana;">s findings conclude that factors that inhibit gas supply in Ghana include the lack of growth and supply investment in the gas supply industry, power sector debt on the gas market, and the lack of an extensive distribution infrastructure/network. Also, the gas industry in Ghana lacks the requisite investment drive which culminates into inefficiency and ultimately undermines efforts to achieve sustainable power generation. Politics influence in issues relating to gas supplies in Ghana inhibits long-term supply relationships and permanent infrastructure in gas supply, both locally and on the world market.
