Monirul Islam

Volumetric and Viscometric Properties of Aqueous Solutions of N-Methylformamide, 1,2-Diaminopropane and 2-Methylpropane-2-ol

Density and viscosity of aqueous solutions of N-methylformamide (NMF), 1,2-diaminopropane (DAP) and 2-methylpropane-2-ol (MPL) have been measured precisely over the entire composition range (i.e., 1 ≥ x 2 ≥ 0) at five equidistant temperatures ranging from 298.15 to 318.15 K. Excess molar volume (VE m ) and excess viscosity (η E ) have been calculated from measured density and viscosity data, respectively. Excess molar volume and excess viscosity have been fitted by the least squares method to the four parameters Redlich-Kister equation. The results have been interpreted on the basis of (i) interstitial incorporation, (ii) breakdown of the structure of pure liquids, (iii) hydrophobic hydration, (iv) hydrophobic interaction and (v) association between dissimilar liquids.

Viscosity of aqueous solutions of 2-propyne-1-ol, 2-methyl-3-butyne-2-ol and 3-butene-2-ol

Viscosities of aqueous solutions of 2-propyne-1-ol (propargyl alcohol), 2-methyl-3-butyne-2-ol and 3-butene-2-ol have been measured at temperatures 308.15, 313.15, 318.15, 323.15 and 328.15 K over the entire composition range. Viscosity of the aqueous solutions of 2-methyl-3-butyne-2-ol and 3-butene-2-ol increases up to a maximum value and then starts decreasing almost linearly as the mole fraction of alcohol increases. 2-Methyl-3-butyne-2-ol + water and 3-butene-2-ol + water systems exhibit maxima around 0.5 and 0.2 mole fraction, respectively. Conversely, 2-propyne-1-ol + water system shows a rapid initial increase in viscosity up to 0.3 mole fraction followed by a slow steady increase as the mole fraction of alcohol increases to its pure state. Plots of excess viscosities against mole fraction of organic solutes for all the systems exhibit a sharp increase in η E to reach a well defined maxima, after which the curves show a descending trend. The variations of viscosity and excess viscosity with the composition of the mixtures have been interpreted in terms of hydrophobic and hydrophilic interactions between the species forming the mixtures.

Molecular and biochemical mechanisms associated with differential responses to drought tolerance in wheat (Triticum aestivum L.)

Drought stress is a common abiotic stress in wheat. In this study, PEG-induced drought stress caused significant decline in morpho-physiological characteristics in Bijoy but not in BG-25, suggesting that drought tolerance mechanisms exist in BG-25. Semi-quantitative RT-PCR (reverse transcriptase) revealed the upregulation of TaCRT1 (calreticulin Ca2+-binding protein) and DREB1A (dehydration responsive transcription factor) transcripts in drought-stressed roots of BG-25 and Bijoy, albeit to a lesser extent. These imply that increased TaCRT1 expression may be associated with the survival of the wheat plants under drought conditions. In addition, DREB1A suggests its involvement in gene regulation associated with drought tolerance. Higher antioxidant enzyme capacity (catalase, peroxidase and glutathione reductase) along with less MDA content in roots of BG-25 suggests that wheat tolerance to drought stress could be associated with higher oxidative scavenging ability. Finally, elevated S-metabolites (glutathione, methionine and cysteine) and proline in BG-25 indicates that strong antioxidant defense play a vital role in drought tolerance in wheat.

Auxin signaling is closely associated with zn-efficiency in rice (oryza sativa L.)

ABSTRACT This study elucidates the involvement of auxin with Zn-efficiency (ZE) in Zn-efficient rice var. Pokkali. Pokkali showed no significant decrease in morpho-physiological features, electrolyte leakage and total soluble proteins due to Zn deficiency as compared with Zn-sufficient seedlings. However, auxin inhibitor under Zn deficiency severely affected these characteristics, suggesting that ZE is associated with auxin signaling in rice. Results further revealed significant decreases in the expression of Zn transporter genes (OsIRT1, OsZIP4 and OsZIP1), OsDMAS1 (deoxymugeneic acid synthase) and phytochelatin in roots due to auxin inhibitor. It implies that auxin signaling may trigger Zn uptake, transport and chelation in rice seedlings to withstand Zn-deficiency. Further, significant reduction of major S-metabolites (cysteine, methionine, glutathione) and antioxidant enzymes (superoxide dismutase and glutathione reductase) along with increased H2O2 content, due to auxin inhibitor under Zn deficiency compared with controls. Taken together, these findings reveal that mechanisms associated with ZE in Pokkali are dependent on auxin signaling.

Pattern analysis of trace gases over Bangladesh using satellite remote sensing

Trace gases are important components for climate change process, and Earth’s climate is sensitive to change in their atmospheric concentrations; therefore, proper assessment of trace gases is essential for ongoing global climate simulation. The spatio-temporal variations of four trace gases, namely carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and carbon dioxide (CO2), over Bangladesh during the last decade are analysed using the remote-sensing data sets of the Atmospheric Infrared Sounder (AIRS) and Ozone Monitoring Instrument (OMI). Monthly, seasonal, and annual mean variations of trace gases were assessed. Higher CO, O3, and CO2 concentrations show west-to-east gradient, indicating the impact of both local meteorology and emissions on variations in trace gases. On the other hand, total NO2 concentration increases over Dhaka because of large population density, high traffic emission, larger industrial activities, and highly polluted air. The inter-annual variations of trace gases are mainly due to large-scale climatic phenomena such as El Niño and La Niña conditions. All the trace gases show strong seasonality, with higher levels during pre-monsoon season and lower levels during monsoon season, which are caused by the seasonal variations in biomass burning (BB), long-range transportation, and rainfall in South and Southeast Asia (S–SE Asia). However, O3 concentration reveals minimum loading during winter season, associated with the reduction of O3 formation in cold days due to insufficient heat. These findings are important to estimate regional climate variability due to trace gases.

Genetic variation in cadmium tolerance is related to transport and antioxidant activities in field peas (Pisum sativum L.)

ABSTRACT This study elucidates mechanisms conferring differential tolerance to cadmium (Cd) stress in contrasting pea genotypes. Cd stress caused a significant decline in morphophysiological traits in Hurst Green Shaft but not in Kelvedon Wonder, suggesting that Cd-stress tolerance does exist in Kelvedon Wonder. Results showed a significant increase of Cd in roots of both genotypes but not in leaves of Kelvedon Wonder due to Cd stress. Consistently, RIT1 (Fe transporter) transcript showed downregulation and upregulation in Kelvedon Wonder and Hurst Green Shaft, respectively, in leaves upon Cd exposure. This consistent atomic absorption spectroscopy and expression data suggest that limiting Cd translocation by decreased RIT1 expression is related to the ability of Kelvedon Wonder plants to cope with Cd stress. Furthermore, an enhanced antioxidant activity was only observed in leaves of Kelvedon Wonder under Cd stress. Finally, high-performance liquid chromatography analysis showed elevated cysteine, methionine and glutathione in leaves of Kelvedon Wonder, suggesting better protection of pea plants from Cd-induced oxidative stress. Our findings reveal that differential tolerance to Cd stress is mainly attributed to Cd translocation and antioxidant defense in pea plants, which can be further implemented for Cd-free transgenic peas to limit environmental toxicity and health hazards.

Effect of soil and environment on winter vegetables production

Soil and environment is the major part of crop production. Vegetables need good soil and environment for better production.1 Mainly vegetable produce in winter but all over the season vegetables can grow. In vegetables, production depends on soil and environment.2 In soil PH, soil moisture, soil humidity, soil texture, and soil fertility are the needs for good vegetables.3 Other than temperature, rainfall, humidity, and light intensity are also need for vegetable production. Mainly vegetable production depends on the environment.4 Generally, Bangladesh has six seasons viz. Grisma (Summer), Barsa (Rainy), Sarat (Autumn), Hemanta (Late Autumn), Shhit (Winter), And Basanta (Spring). In Bangladesh, vegetables produced in mainly to two seasons such as winter and summer. Winter seasons are the major seasons for vegetable production in Bangladesh.5 In Bangladesh, 70% vegetables can grow in winter seasons such as Cole crop, brinjal, tomato, and different types of leafy vegetables.6 It needs a low temperature below than 20°C. Winter season called vegetable seasons in our country.7 All vegetables cannot grow in all regions in Bangladesh. It depends on soil types such as potato can grow in the north part of the region such as Thakurgon, Rangpur, Bogra, and south part Munsigonj. This soil and environment are good for better potato production.7 Maximum Cole crop grown in the north part of our country because of the environment is better for Cole vegetable production. Saline soil is not suitable for vegetable production. The vegetable cannot tolerant high rainfall, saline soil, and high temperature. According to statistics, a maximum natural hazard in Bangladesh occurred in April to September in the summer seasons.7 Humidity and temperatures in this season are higher than the winter season. Flood decreases the production area in summer seasons.8 Vegetable forms a group of specialized crops. They are important economically and from a health point of view. They fit well in most farming systems as their maturity period from planting to harvest is short.9 With the ever-increasing human population, vegetables have played an important role in our national economy.10 Vegetables provide maximum output and more income per unit area of land to small-scale farmers, particularly when compared to cereals.11 A wide range of vegetables are grown in Bangladesh.12 The summer vegetables are mostly indigenous whereas most of the winter vegetables are of European origin. Production of vegetables in the cool season is hazard free and blessed with a favourable climate.13 During summer, vegetable production is affected by the flood, cyclones, and other factors associated with high temperature, humidity and rainfall.1 At present, vegetables are grown in about 4.52 lac hectares of land with a total production of 30.8 lac metrictons.7 Vegetable production in Bangladesh is far below requirement. BARI and other organization have developed a good number of HYV of different vegetable crops including improved production technology.6 If farmers use these technologies then internal requirement will be met up even we can export some vegetables abroad. The most important vegetables are winter vegetables.7 Relations of soil and environment conditions are essential for winter vegetable productions. Different types of soil present in our country in the different region.14 Winter season also called Rabi seasons. Rabi season start from October and last week of April. In this season, temperature varies from 10 to 21°C. The main purpose of this study is to explore the responsible factors of soil and environment for yield variation of winter vegetables.

Quality analysis, miceller behavior, and environmental impact of some laundry detergents available in Bangladesh

The cleansing efficiencies of laundry detergents depend on composition and variation of ingredients such as surfactants, phosphate, and co-builders. Among these ingredients, surfactants and phosphate are considered as hazardous materials. Knowledge on compositions and micellar behavior is very useful for understanding their cleansing efficiencies and environmental impact. With this view, composition, critical micelle concentration, and dissolved oxygen level in aqueous solution of some laundry detergents available in Bangladesh such as keya, Wheel Power White, Tibet, Surf Excel, and Chaka were determined. Surfactant and phosphate were found to be maximum in Surf Excel and Wheel Power White, respectively, while both of the ingredients were found to be minimum in Tibet. The critical micelle concentration decreased with increasing surfactant content. The amount of laundry detergents required for efficient cleansing was found to be minimum for Surf Excel and maximum for Chaka; however, cleansing cost was the highest for Surf Excel and the lowest for Tibet. The maximum amount of surfactants and phosphate was discharged by Surf Excel and Wheel Power White, respectively, while discharges of both of the ingredients were minimum for Tibet. The maximum decrease of dissolved oxygen level was caused by Surf Excel and the minimum by Tibet. Therefore, it can be concluded that Tibet is cost-effective and environment friendly, whereas Surf Excel and Wheel Power White are expensive and pose a threat to water environment.