Rescheduling of wet season (T. Aman) rice planting for cropping intensification in coastal Bangladesh

About 1.0 million ha coastal lands in Bangladesh are mono-cropped suffer from varying degree of soil salinity, waterlogging and climate vulnerability. Low yielding, traditional T. Aman rice is grown only in wet season. Growing non-rice crop after late harvested T. Aman rice is not profitable. This study was aimed to introduce high yielding, short duration T. Aman rice varieties for advancing its harvesting time and to make the avenue for timely establishment of dry season crops. Varietal trials were made at Dacope and Amtali under ACIAR funded project during 2016-2018 and compared with local cultivars. Among tested varieties BRRI dhan76 followed by BRRI dhan77 and BRRI dhan54 in Dacope and BRRI dhan77 followed by BRRI dhan76 and BRRI dhan54 in Amtali were preferred for 0.5–1.0 tha−1 yield advantage and 15–25 days earliness compared to traditional varieties. Early harvesting of T. Aman created the avenue of timely establishment of rice and non-rice crops depending on availability of fresh water and thus crop intensification and land productivity was improved. The new cropping system increased annual rice yield and farmers’ profits by 1.5- to 2-folds compared with traditional system without environmental degradation. This technique can be replicated in similar coastal zones of Bangladesh

Experimental investigation on surface tension of metal oxide-water nanofluids

"Nanofluids", smart fluids with advanced thermal properties, have proved their promising potential in enhancing the heat transfer performance of a thermal system as well as mitigating the energy crisis of the universe. Besides all other's thermo-physical properties, surface tension governs the transport of the liquid and plays a crucial role in the heat transfer. However, the studies on the effect of surface tension on the performance of nanofluids are quite a few and demonstrated debatable results. Therefore, the present experimental study attempts to determine the surface tension of the nanofluids by dispersing Al2O3, TiO2, and SiO2 nanoparticles in Distilled Water (DW). The experiment was conducted by using the most common Du-Hotly ring method in DCAT11EC automatic surface tensiometer. In this study, the authors analyzed all the possible effects on surface tension of nanofluids with the change in concentrations (from 0.05 to 025 vol.) and temperatures (from 30 degrees C to 50 degrees C), as well as the impact of various nanoparticles along with their sizes. The results indicate that the surface tension of the nanofluids increases with concentration, whereas decreases with the increase in temperature. Besides, the smaller nanoparticles exhibit lower surface tension than the larger ones. All in all, the surface tension of the nanofluids augments from 3.1 to 7.8 in compared with the base fluid for concentrations of 0.05 vol. to 0.25 vol. and temperatures of 30 degrees C to 50 degrees C, in all cases. (C) 2015 Elsevier Ltd. All rights reserved

Chemical genomics of cancer chemopreventive dithiolethiones

3H-1,2-dithiole-3-thione (D3T) and its analogues 4-methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (OLT) and 5-tert-butyl-3H-1,2-dithiole-3-thione (TBD) are chemopreventive agents that block or diminish early stages of carcinogenesis by inducing activities of detoxication enzymes. While OLT has been used in clinical trials, TBD has been shown to be more efficacious and possibly less toxic than OLT in animals. Here, we utilize a robust and high-resolution chemical genomics procedure to examine the pharmacological structure–activity relationships of these compounds in livers of male rats by microarray analyses. We identified 226 differentially expressed genes that were common to all treatments. Functional analysis identified the relation of these genes to glutathione metabolism and the nuclear factor, erythroid derived 2-related factor 2 pathway (Nrf2) that is known to regulate many of the protective actions of dithiolethiones. OLT and TBD were shown to have similar efficacies and both were weaker than D3T. In addition, we identified 40 genes whose responses were common to OLT and TBD, yet distinct from D3T. As inhibition of cytochrome P450 (CYP) has been associated with the effects of OLT on CYP expression, we determined the half maximal inhibitory concentration (IC50) values for inhibition of CYP1A2. The rank order of inhibitor potency was OLT ≫ TBD ≫ D3T, with IC50 values estimated as 0.2, 12.8 and >100 μM, respectively. Functional analysis revealed that OLT and TBD, in addition to their effects on CYP, modulate liver lipid metabolism, especially fatty acids. Together, these findings provide new insight into the actions of clinically relevant and lead dithiolethione analogues

Docosahexaenoic Acid Inhibits UVB-Induced Activation of NF-κB and Expression of COX-2 and NOX-4 in HR-1 Hairless Mouse Skin by Blocking MSK1 Signaling

Exposure to ultraviolet-B (UVB) radiation induces inflammation and photocarcinogenesis in mammalian skin. Docosahexaenoic acid (DHA), a representative ω-3 polyunsaturated fatty acid, has been reported to possess anti-inflammatory and chemopreventive properties. In the present study, we investigated the molecular mechanisms underlying the inhibitory effects of DHA on UVB-induced inflammation in mouse skin. Our study revealed that topical application of DHA prior to UVB irradiation attenuated the expression of cyclooxygenase-2 (COX-2) and NAD(P)H:oxidase-4 (NOX-4) in hairless mouse skin. DHA pretreatment also attenuated UVB-induced DNA binding of nuclear factor-kappaB (NF-κB) through the inhibition of phosphorylation of IκB kinase-α/β, phosphorylation and degradation of IκBα and nuclear translocation of p50 and p65. In addition, UVB-induced phosphorylation of p65 at the serine 276 residue was significantly inhibited by topical application of DHA. Irradiation with UVB induced phosphorylation of mitogen and stress-activated kinase-1 (MSK1), extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinase, and all these events were attenuated by pretreatment with DHA. Blocking ERK and p38 MAP kinase signaling by U0126 and SB203580, respectively, diminished MSK1 phosphorylation in UVB-irradiated mouse skin. Pretreatment with H-89, a pharmacological inhibitor of MSK1, abrogated UVB-induced activation of NF-κB and the expression of COX-2 and NOX-4 in mouse skin. In conclusion, topically applied DHA inhibits the UVB-induced activation of NF-κB and the expression of COX-2 and NOX-4 by blocking the phosphorylation of MSK1, a kinase downstream of ERK and p38 MAP kinase, in hairless mouse skin

Uncertainties related to the assignment of a toxic equivalency factor for 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin

The Toxic Equivalency Factor (TEF) approach is a methodology that assigns relative toxicity values to structurally related chemicals in comparison to a reference chemical. For the polychlorinated dibenzo-p-dioxins (PCDDs), the reference is the most potent congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Here, we critically review the literature on the effects of a weak PCDD, 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin (OCDD), and describe the uncertainties of assigning its TEF. PCDDs, including OCDD, are less potent in human cell models compared to the rat models from which the TEF are estimated. This lack of concordance is even more pronounced with the weaker congeners such as OCDD. Furthermore, OCDD is also likely to compete with TCDD for binding to cytochrome P4501A2 (CYP1A2), effectively decreasing the hepatic tissue/fat ratio of TCDD. Overall, the predictive value of TEFs would be improved by incorporating into this number the relative sensitivity of human cell responses compared to rodent responses, by determining the toxicological effects of altering the tissue distribution of dioxin-like compounds through competition for CYP-binding sites, and by understanding the mechanism of cancer causation of any dioxin and whether this mechanism is conserved in humans and at equivalent doses. © 2005 Elsevier Inc. All rights reserved

Experimental investigation on thermo physical properties of single walled carbon nanotube nanofluids

This experimental study is aimed to measure and analyze the thermal conductivity, viscosity, and specific heat of water based single walled carbon nanotube (SWCNT) nanofluids in presence of sodium dodecyl sulfate (SDS) surfactant. The surfactant was used to prepare stable nanofluids and the stability of SWCNT nanofluids of five volume concentrations (0.05-0.25 vol%) is observed good. The measured values of thermal conductivity in the range of 0.615-0.892 W/m K, viscosity in the range of 0.67-1.28 mPa s, and the specific heat in the range of 2.97-3.90 kJ/kg degrees C, were observed for temperature rising from 20 to 60 degrees C with an interval of 10 degrees C as the volume concentration increased from 0.05 to 0.25 vol%. The maximum thermal conductivity enhancement of 36.39% compared to water is observed for 0.25 vol% at 60 degrees C. The viscosity of SWCNT nanofluids exhibited a non-Newtonian shear-thinning behavior due to the alignment of nanotube clusters and agglomerates with increasing shear rate. The temperature and volume concentrations have effect on specific heat as well and it decreases with particle loadings while increases with temperature

Energy and Exergy Analyses of a Flat Plate Solar Collector Using Various Nanofluids: An Analytical Approach

Energy and exergy (EnE) efficiencies are considered the most important parameters to compare the performance of various thermal systems. In this paper, an analysis was carried out for EnE efficiencies of a flat plate solar collector (FPSC) using four different kinds of nanofluids as flowing mediums, namely, Al2O3/water, MgO/water, TiO2/water, and CuO/water, and compared with water as a flowing medium (traditional base fluid). The analysis considered nanofluids made of nanomaterials’ volume fractions of 1–4% with water. The volume flow rates of nanofluids and water were 1 to 4 L/min. The solar collector′s highest EnE efficiency values were obtained for CuO/water nanofluid among the four types of nanofluids mentioned above. The EnE efficiencies of the CuO nanofluid-operated solar collector were 38.21% and 34.06%, respectively, which is significantly higher than that of water-operated solar collectors. For the same volume flow rate, the mass flow rate was found to be 15.95% higher than water for the CuO nanofluid. The EnE efficiency of FPSC can also be increased by increasing the density and reducing the specific heat of the flowing medium

Textile Effluent Treatment Plant Sludge: Characterization and Utilization in Building Materials

The main objective of this study is to characterize and find a potential use of textile effluent treatment plant (ETP) sludge produced in Bangladesh. Textile ETP sludge collected from the local textile industries have been characterized in the laboratory. The physicochemical and engineering properties of the sludge have been studied. Collected ETP sludge has been processed to get cement-like fine powder that has been used for partial replacement of Portland cement/sand in the composition of the mortar and concrete specimens. Different mechanical (compressive and flexural strength), physical (water absorption) and morphological (porosity) properties of the test specimens have been evaluated. The test result shows that the addition of sludge in the mortar and concrete composition as a substitution of Portland cement or sand decreases the compressive strength and flexural strength, and increases the water absorption and porosity of the mortar and concrete specimens. Leaching study, conducted for the sludge-based mortar and concrete specimens following tank leaching test procedure, reveals that the concentration of leached metals is quite low than the limits specified by the Department of Environment in Bangladesh. These results amply demonstrate that textile ETP sludge can be utilized for making non-structural building components where lower strength is justified