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| 2. |
- Ahmed, K. M., et al.
(författare)
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Groundwater quality contrasts between Upper and Lower Dupi Tila Aquifers in Megacity Dhaka, Bangladesh
- 2011
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Ingår i: Groundwater quality contrasts between Upper and Lower Dupi Tila Aquifers in Megacity Dhaka, Bangladesh. - 9781907161162 ; , s. 71-74
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Konferensbidrag (refereegranskat)abstract
- Dhaka is one of the fastest growing megacities of the world and is set to become the third largest by 2025. Currently about 86% of the municipal water supply comes from over 500 wells drilled in the Dupi Tila aquifers underlying the city. The Upper Dupi Tila aquifer (UDTA) is overexploited and a large part has been dewatered; abstractions from the lower Dupi Tila started only recently. Results of water analysis and EC surveys have been used to decipher the variations in groundwater quality in the UDTA and LDTA. EC surveys reveal a systematic deterioration of water quality in the vicinity of the Buriganga River in southeast Dhaka. The UDTA is more widely affected by anthropogenic processes than the LDTA, which still largely exhibits its intrinsic water quality characteristics. Regular monitoring and proper management practices are essential to protect the quality of this precarious resource.
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| 4. |
- Ahmed, Nur, et al.
(författare)
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Impact of climate change on rice insect pests and their natural enemies
- 2013
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Konferensbidrag (refereegranskat)abstract
- Rice is one of the important staple foods for half of the world population particularly Asian countries for their livelihood, socio-economic and nutrition. Global warming is predicted to increase frequency of precipitation/rainfall, intensity of drought and solar-radiation/UV-B radiation which might affect the intensity and severity of rice pests in one hand, but also change in other friendly arthropods on the other hand. The present studies discuss the influence of climatic factors (temperature and rainfall) on yellow stem borer (YSB), brown planthopper (BPH), green leafhopper (GLH) and their natural enemies (spider, lady bird beetle, green mirid bug). Light trap and sweep net catches of arthropods from different rice habitats were used in this study. For GLH there is a strong periodicity at 6 months and a somewhat weaker periodicity at 12 months followed by an even weaker periodicity at 3 months, especially valid for both methods of data collection (light trap and sweep-net data). Finally, for GMB there is a strong periodicity at 6 months and a somewhat weaker periodicity at 3 months followed by an even weaker periodicity at 4 months. There is a general increasing trend over the ten years seems to be present in the GLH. This corresponds to that the abundance in 2005 is generally 15 times larger than in January 1996. For LBB, there is an increasing trend of log abundance of LBB over time and shows a strong periodicity at 3 months and a somewhat weaker periodicity at 4 months followed by an even weaker periodicity at about 6 months. For Spider there is a strong periodicity at 2.4 months and a somewhat weaker periodicity at 4 months followed by an even weaker periodicities at about 3 months and 6 months. Results show an increase of maximum temperature of approximately 0.5 to 1°C over 10 years.
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| 5. |
- Ahmed, Sultan, et al.
(författare)
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Arsenic-Associated Oxidative stress, Inflammation, and Immune Disruption in Human Placenta and Cord Blood
- 2011
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Ingår i: Journal of Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 119:2, s. 258-264
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Arsenic (As) exposure during pregnancy induces oxidative stress and increases the risk of fetal loss and low birth weight. OBJECTIVES: This study aimed to elucidate the effects of As exposure on immune markers in the placenta and cord blood, and the involvement of oxidative stress. METHODS: Pregnant women were enrolled around gestational week (GW) 8 in our longitudinal, population-based, mother-child cohort in Matlab, an area in rural Bangladesh with large variations in As concentrations in well water. Women (n=130) delivering at local clinics were included in the present study. We collected maternal urine twice during pregnancy (GW8 and 30) for measurements of As, and placenta and cord blood at delivery for assessment of immune and inflammatory markers. Placental markers were measured by immunohistochemistry and cord blood cytokines by multiplex cytokine assay. RESULTS: In multivariable adjusted models, maternal urinary As (U-As) exposure both at GW8 and 30 was significantly positively associated with placental markers of 8-oxoguanine (8-oxoG) and IL-1β, U-As at GW8 with TNF- α and IFN-γ, U-As at GW30 with leptin , and U-As at GW8 was inversely associated with CD3-T cells in the placenta. Cord blood cytokines (IL-1β, IL-8, IFN-γ, TNF-α) showed a U-shaped association with U-As at GW30. Placental 8-oxoG was significantly positively associated with placental pro-inflammatory cytokines. Multivariable adjusted analyses suggested that enhanced placental cytokine expression (TNF-α and IFN-γ) was primarily influenced by oxidative stress, while leptin expression appeared to be mostly mediated by As, and IL-1β appeared to be influenced by both oxidative stress and As. CONCLUSION: As exposure during pregnancy appeared to enhance placental inflammatory responses (in part by increasing oxidative stress), reduce placental T cells, and alter cord blood cytokines. These findings suggest that effects of As on immune function may contribute to impaired fetal and infant health.
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| 8. |
- Willander, Magnus, et al.
(författare)
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Applications of Zinc Oxide Nanowires for Bio-photonics and Bio-electronics
- 2011
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Ingår i: Proceedings of SPIE Volume 7940. - Bellingham, Washington, USA : SPIE - International Society for Optical Engineering. - 9780819484772
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Using zinc oxide (ZnO) nanostructures, nanorods (NRs) and nanoparticles (NPs) grown on different substrates (sub-micrometer glass pipettes, thin silver wire and on plastic substrate) different bio-sensors were demonstrated. The demonstrated sensors are based on potentiometric approach and are sensitive to the ionic metals and biological analyte in question. For each case a selective membrane or enzyme was used. The measurements were performed for intracellular environment as well as in some cases (cholesterol and uric acid). The selectivity in each case is tuned according to the element to be sensed. Moreover we also developed photodynamic therapy approach based on the use of ZnO NRs and NPs. Necrosis/apoptosis was possible to achieve for different types of cancerous cell. The results indicate that the ZnO with its UV and white band emissions is beneficial to photodynamic therapy technology.
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| 9. |
- Djurfeldt, Göran, et al.
(författare)
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Afrint database
- 2011
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Annan publikation (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Kishwar, Sultana, et al.
(författare)
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Investigation of the phototoxic effect of ZnO nanorods on fibroblasts and melanoma human cells
- 2014
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Ingår i: Laser Physics Letters. - : Institute of Physics (IOP). - 1612-2011 .- 1612-202X. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Photo-cytotoxicity of zinc oxide (ZnO) nanowires (NWs) either bare or conjugated with photosensitizers was studied in dark and after ultraviolet light exposure, in human melanoma and foreskin fibroblast cells. ZnO NWs were grown on the capillary tip and then coated with photosensitizer. This coated tip was used as pointer for intracellular insertion of ZnO NWs and photosensitizer. ZnO NWs pointer was inserted into a specific cell and then irradiated with ultraviolet (UVA), which led to loss of mitochondrial membrane potential, as estimated by loss of the Mitotracker Red staining. Dissolved ZnO NWs showed cytotoxicity as detected by MTT viability assay and morphological evaluation. UVA-irradiation enhanced the toxicity and caused the production of reactive oxygen species (ROS) resulting in cell necrosis. ZnO NWs were photo-toxic for both normal and cancer cells, questioning their bio-safety.
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