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Chemical Composition and Source Characterization of Hailstones in Dhaka, Bangladesh

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Journal of Geoscience and Environment Protection 2018年第9期6卷 71-82页

作者： Rasheda Aktar Samiha Morshad Ahmed Mohammad Shohel abdus salam Department of Chemistry Faculty of Science University of Dhaka Dhaka Bangladesh Department of Chemistry University of Iowa Iowa City IA USA

A comprehensive analysis on the chemical composition and source apportionment of hailstone samples were conducted in Dhaka, Bangladesh. pH, electrical conductivity (EC), total dissolved solids (TDS), water soluble ions (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, NO3-, HCO3-) and trace metals (Zn, Fe, Cu, Mn) of hailstone were determined. The result revealed that the average pH, EC, TDS were 6.95 ± 0.54, 356.3 ± 150.6 μS·cm-1 and 17.5 ± 2.89 mg·L-1, respectively. The water soluble ions followed the order: Ca2+ > Cl-1 > SO42- > HCO3- > Na+ > Mg2+ > K+ > NO3-. The concentrations of trace metals ranged in order with Zn > Fe > Cu, while the concentration of Mn was below detection limit. Sodium adsorption ratio (SAR) was 0.20 ± 0.09 meqL-1 which indicates it is benign to plants and safe for irrigation. The order of neutralization factor (calculated with average concentrations) found in hailstone was NFCa(1.16) > NFMg (0.36) > NFK(0.32) which were originated from earth crust. Notable correlation was found in between soil tracers Ca2+ and Mg2+ (r = 0.87), indicating their common source dust. Enrichment factor analysis revealed that Ca2+, Mg2+ and K+ are mainly from crust, whereas NO3- and SO42- are mainly attributable to anthropogenic origins. Further source contribution analysis revealed that anthropogenic actions accounted for 99.2% of total NO3- and 89.6% of total SO42-, while 99.2% of total Ca2+ and 95% Mg2+ were from crustal source.

关键词： Hailstone Water Soluble Ion Trace Metal Source Apportionment

The Traveling Wave Solutions of Space-Time Fractional Partial Differential Equations by Modified Kudryashov Method

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Journal of Applied Mathematics and Physics 2020年第11期8卷 2683-2690页

作者： Md. Mahfujur Rahman Umme Habiba Md. abdus salam Mousumi Datta Department of Mathematics Mawlana Bhashani Science and Technology University Tangail Bangladesh

In this paper, the modified Kudryashov method is employed to find the traveling wave solutions of two well-known space-time fractional partial differential equations, namely the Zakharov Kuznetshov Benjamin Bona Mahony equation and Kolmogorov Petrovskii Piskunov equation, and as a helping tool, the sense of modified Riemann-Liouville derivative is also used. The propagation properties of obtained solutions are investigated where the graphical representations and justifications of the results are done by mathematical software Maple.

关键词： Traveling Wave Solutions Modified Kudryashov Method Zakharov Kuznetshov Benjamin Bona Mahony (ZKBBM) Equation Kolmogorov Petrovskii Piskunov (KPP) Equation

Sources of Nitrogen in Combination with Systems of Irrigation Influence the Productivity of Modern Rice(Oryza sativa L.)Cultivars during Dry Season in Sub-Tropical Environment

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Phyton-International Journal of Experimental Botany 2022年第8期91卷 1687-1708页

作者： Uttam Kumer Sarker Md.Romij Uddin Ahmed Khairul Hasan Md.Abdur Rahman Sarkar Md.abdus salam Md.Alamgir Hossain Eldessoky S.Dessoky Ismail A.Ismail Department of Agronomy Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Crop Botany Bangladesh Agricultural UniversityMymensingh2202Bangladesh Department of Biology College of ScienceTaif UniversityTaif21944Saudi Arabia

In irrigated agricultural systems,nitrogen(N)and water are the vital resources for sustainability of the crop production in the modern era of climate *** current study aimed to assess the impact of water and N management on the productivity of irrigated rice *** the context,a field observation was done at the research farm of Bangladesh Agricultural University,Mymensingh,during dry seasons in consecutive two years(2018–2019 and 2019–2020).The experiments were set up following split-plot design assigning water management in the main plots,nitrogen management in the sub-plots,and the cultivars were approved in the split-split plot with three *** two years observation,it was revealed that rice cultivar Binadhan-8 gave the maximum value of leaf area index,number effective tillers hill-1 and grains panicle-1 which lead to the higher grain yield(GY).Substantial relationships were observed among the concentration of N,growth,total dry matter(TDM)and N content,N uptake,N utilization effectiveness,and ***,with little exception,the Combined effect of water and N,cultivars and water management were varied significantly for all ***,the results of the current study concluded that application of irrigation at 8 days after the disappearance of ponded water and source of 105 kg N ha-1 from PU+Poultry manure are the best management approach for the excellent performance of rice cultivar Binadhan-8.

关键词： Growth stage high yielding rice cultivar internal N use efficiency water productivity

Synthesis, spectral characterization and biological activities of Organotin(IV) complexes with <i>ortho</i>-vanillin-2-hydrazinopyridine (VHP)

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Open Journal of Inorganic Chemistry 2012年第2期2卷 22-27页

作者： Norrihan Sam Md Abu Affan Md abdus salam Fasihuddin B. Ahmad Mohd Razip Asaruddin Department of Chemistry Faculty of Resource Science and Technology Universiti Malaysia Sarawak Kota Samarahan Malaysia

Five new organotin(IV) complexes of ortho-vanillin-2-hydrazinopyridine hydrazone with formula [RnSnCl4–n(VHP)] [R = Me2, n = 2 (2);R = Ph2, n = 2 (3);R= nBu2, n = 2 (4);R = nBu, n = 2 (5) and R = 1, n = 0 (6)] have been synthesized by direct reaction of ortho-vanillin-2-hydrazinopyridine hydrazone [(VHP), (1)], base and organotin(IV) chloride(s) in absolute methanol. The hydrazone ligand [(VHP), (1)] and its organotin(IV) complexes (2-6) have been characterized by UV-Visible, FT-IR and 1H NMR spectral studies. Spectroscopic data suggested that in the complexes (2-4), the ligand (1) acted as a neutral bidentate ligand and is coordinated to the tin(IV) atom via the azomethine nitrogen and pyridyl nitrogen atoms, whereas the ligand (1) acted as a uninegative tridentate ligand and coordinated to the tin(IV) atom through phenolic-O, azomethine-N and pyridyl-N atoms in complexes (5-6). The toxicity of the ligand (1) and its organotin (IV) complexes (2-6) were determined against Artemia salina. Organotin(IV) complexes showed moderate activity against Artemia salina. The ligand (1) and its organotin(IV) complexes (2-6) were also tested against four types of bacteria namely Bacillus cereus, Staphylococcus aureus, Escherichia coli and Enterobacter aerogenes. All organotin(IV) complexes and the free ligand (1) showed better antibacterial activities against bacteria. Among the organotin(IV) complexes (2-6), diphenyltin(IV) complex (3) showed higher activity against the four types of bacteria.

关键词： Hydrazone Organotin(IV) Complexes Spectral Analyses Toxicity Antibacterial Activity

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科学与社会 1990年第3期 23-24页

作者： abdus salam 海燕里雅斯特国际理论物理学中心

我们的这个星球居住着截然不同的两种人:发展中的和发达的,富有的和贫穷的。区别这两者的是从根本上说明在掌握和使用现今科学技术时出现不同情况的雄心、能力和干劲。这是引言,但是经济学家们并不同意这样的观点。现在我又发现了不同... 详细信息

我们的这个星球居住着截然不同的两种人:发展中的和发达的,富有的和贫穷的。区别这两者的是从根本上说明在掌握和使用现今科学技术时出现不同情况的雄心、能力和干劲。这是引言,但是经济学家们并不同意这样的观点。现在我又发现了不同意这种观点的金融家。据我看,这是个非常重要的观点,是一种不言而喻的事情。依据在座各位的观点,我料想这也是不言而喻的。在科学技术于南方起飞之前,必须说服社会的领袖们。我们的统治者,我们的计划者、

关键词：领域国际科学合作

Accelerated Aqueous Solubility and Antibacterial Activity of Cefuroxime Axetil Using Microcrystalline Cellulose as Carrier

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Pharmacology & Pharmacy 2020年第8期11卷 159-173页

作者： Moushumi Tabassoom salam Ashim Kumar Akito Hata Hiromu Kondo Md. abdus salam Mir Imam Ibne Wahed Md. Rafiqul Islam Khan Ranjan Kumar Barman Laboratory of Pharmaceutics Department of Pharmacy Faculty of Science University of Rajshahi Rajshahi Bangladesh Laboratory of Pharmaceutical Engineering & Drug Delivery Science School of Pharmaceutical Science University of Shizuoka Shizuoka Japan Department of Basic Medical Sciences Faculty of Medicine International Islamic University Malaysia Kuantan Malaysia

This investigation was undertaken to enhance the solubility and consequent antibacterial activity of cefuroxime axetil (CA), a β-lactamase-stable broad spectrum second generation cephalosporin through solid dispersion (SD) technique. For this purpose, CA loaded SDs (CSDs) were prepared by solvent evaporation method using different concentrations of microcrystalline cellulose (MCC) as carrier. The CSDs were characterized by in-vitro dissolution study, thermal analysis (DSC), crystallinity (PXRD), interactions (FTIR) and morphology (SEM). Among the formulations, CSD-2 showed the highest dissolution rate which was 2.59-fold higher than pure CA with a drug-carrier (CA: MCC) ratio of 1:3. Enhanced dissolution rate was attributed to conversion of drug from crystalline to amorphous state during preparation of SDs, which was validated by DSC, PXRD, FTIR and SEM analyses. Antibacterial activity of CSD-2 against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) showed 1.94- and 6.75-fold higher relative zone of inhibition (RZOI), respectively than pure CA. CSD-2 has been found to be the most effective optimized formulation in terms of both enhanced dissolution rate and antibacterial activity. Thus, it can be an effective alternative to conventional dosage forms of CA. However, further investigations are needed to validate its pharmacokinetic properties, in-vivo antibacterial efficacy and safety before recommending as a novel

关键词： Cefuroxime Axetil Dispersion Solubility Antibacterial Activity

Synthesis, Spectral Characterization and Thermal Behavior of Newly Derived La(III), Co(III) and Mn(II) Complexes with Schiff Base Derived from Methionine and Salicylaldehyde

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Open Journal of Inorganic Chemistry 2018年第2期8卷 55-69页

作者： Shariful Islam A. K. M. Nur Alam Siddiki Shahida Begum Md. abdus salam Department of Chemistry Faculty of Science University of Dhaka Dhaka Bangladesh

Many metal complexes of Schiff base derived from different amino acids are widely employed as biologically active materials, especially as antibacterial agents. Three new metal [Co(III), Mn(II) and La(III)] complexes with the Schiff base (L) derived from salicylaldehyde and amino acid (methionine) were synthesized and investigated by using various physico-chemical techniques such as elemental analysis, FTIR, UV-visible spectroscopy, magnetic measurement, thermo gravimetric analysis (TGA) and X-ray powder diffraction (XRD) method. From spectral studies, it has been concluded that the synthesized ligand acts as a tetra-dentate molecule, coordinates metal through azomethine nitrogen, sulfur, phenolic oxygen and carboxylate oxygen. UV-visible spectrophotometry showed the characteristic absorption bands corresponding to a square planar geometry for La(III) and Mn(II) metal complexes and tetrahedral geometry for Co(III) complex. The XRD data demonstrated that the manganese and cobalt complexes were crystalline but the lanthanum complex was amorphous in nature. The empirical formula of the synthesized complexes based on analytical data were [Co(C12H13SNO3)]·(NO3), [La(C12H13SNO3)](Cl)(H2O) and [Mn (C12H13SNO3)].

关键词： Schiff Base Metal Complexes Spectral Studies Thermal Behavior X-Ray Powder Diffraction

Water Soluble Ionic Species in the Atmospheric Fine Particulate Matters (PM2.5) in a Southeast Asian Mega City (Dhaka, Bangladesh)

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Open Journal of Air Pollution 2015年第3期4卷 99-108页

作者： abdus salam Md. Assaduzzaman Muhammad Nobi Hossain A. K. M. Nur Alam Siddiki Department of Chemistry Faculty of Science University of Dhaka Dhaka Bangladesh

Atmospheric fine particulate matters (PM2.5) were collected with an Envirotech Instrument (Model APM 550) at the roof of Khundkur Mukarram Hussain Science Building, University of Dhaka, Bangladesh between January and February, 2013. PM2.5 samples were collected on Quartz fiber filters during day and night time. Water soluble ions (sulfate, nitrate, phosphate, chloride, bromide, sodium, potassium and calcium) were analyzed with Ion Chromatography (Model 881, Metrohm Ltd., Switzerland) and Flame photometer (Model PFP7, Jenway, UK). Average PM2.5 mass was 136.1 μg·mǅ during day time and 246.8 μg·mǅ during night time with a total average of 191.4 μg·mǅ. Nighttime PM2.5 concentration was about double compared than that of daytime presumable due to the low ambient temperatures with high emissions from heavy duty vehicles. The 24-hour average PM2.5 mass (average of day and night) was about eight times higher than WHO (25.0 μg·mǅ) and about three times higher than DoE, Bangladesh (65.0 μg·mǅ) limit values. The total average concentrations of sulfate, nitrate, phosphate, bromide, chloride, sodium, potassium and calcium were 5.30, 7.75, 0.62, 0.16, 1.19, 1.30, 8.11, and 3.09 μg·mǅ, respectively. The concentrations of the water soluble ions were much higher during nighttime than daytime except nitrate, bromide and potassium. Excellent correlations were observed between sulfate and nitrate, sodium and chloride, bromide and phosphate indicating joint sources of origin. Potassium, sulfate, nitrate and calcium are the most dominant species in PM2.5. Water soluble ionic components in Dhaka contributed about 15% mass of the PM2.5. Ratio analysis showed that sodium and chloride were from mainly sea salt. Potassium has varieties of sources other than biomass burning. Sulfate and nitrate are mainly from fossil fuel origin. This is the first study of the day and night variation of the water soluble ionic species at the fine particulate mat

关键词： Air Pollution Particulate Matters Water Soluble Ions Sulfate Nitrate

Study of <i>in Vitro</i>Interaction of Sildenafil Citrate with Bovine Serum Albumin by Fluorescence Spectroscopy

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Pharmacology & Pharmacy 2015年第2期6卷 94-101页

作者： Md. abdus salam Md. Rokonujjaman Asma Rahman Ummay Nasrin Sultana Md. Zakir Sultan Department of Chemistry University of Dhaka Dhaka Bangladesh Centre for Advanced Research in Sciences (CARS) University of Dhaka Dhaka Bangladesh

In vitro interaction of sildenafil citrate (SC) with bovine serum albumin (BSA) was investigated at two excitation wavelengths of BSA (280 nm and 293 nm) at two different temperatures (298 K and 308 K) by fluorescence emission spectroscopy. The study showed that quenching of BSA fluores-cence by sildenafil citrate was the result of formation BSA-SC complex with probable involvement of both tryptophan and tyrosine residues of BSA. Fluorescence quenching constant was determined from Stern-Volmer equation, and both static quenching and dynamic quenching were showed for BSA by SC at the conditions. Van’t Hoff equation was used to measure the thermodynamic parameters ΔG, ΔH, and ΔS at the temperatures which indicated that the hydrogen bond and the hydrophobic forces played major roles for BSA-SC complexation. The binding number (n) was found to be ≈1 indicating that one mole BSA bound with one mole SC. The binding affinity of SC to BSA was calculated at different temperatures. The binding constant was decreased with increasing temperatures indicating that stability of BSA-SC complex decreased with increasing temperatures.

关键词： Sildenafil Citrate Bovine Serum Albumin Quenching Fluorescence Spectroscopy