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Modeling of Orientation-Dependent Photoelastic Constants in Cubic Crystal System  [PDF]
Lubna Jahan Rashid Pinky, Shakila Islam, Md. Nur Kutubul Alam, Mohammad Arif Hossain, Md. Rafiqul Islam
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.54027
Abstract:

Euler’s rotation theorem and tensor rotation technique are applied to develop a generalized mathematical model for determining photoelastic constants in arbitrary orientation of cubic crystal system. Two times rotations are utilized in the model relating to crystallographic coordinates with Cartesian coordinates. The symmetry of photoelastic constants is found to have strong dependence with rotation angle. Using the model, one can determine photoelastic constants in any orientation by selecting appropriate rotation angle. The outcome of this study helps to characterize spatial variation of residual strain in crystalline as well as polycrystalline materials having cubic structure using the experimental technique known as scanning infrared polariscope.

Identification of Aflatoxigenic Fungi and Detection of Their Aflatoxin in Red Chilli (Capsicum annuum) Samples Using Direct Cultural Method and HPLC  [PDF]
Md. Nur Hossain, Asma Talukder, Farhana Afroze, Md. Matiur Rahim, Shamima Begum, Md. Zahurul Haque, Monzur Morshed Ahmed
Advances in Microbiology (AiM) , 2018, DOI: 10.4236/aim.2018.81004
Abstract: Aflatoxins are the potential lethal toxin produced by Aspergillus sp. important health hazard throughout the world. In this study, 26 Aspergillus sp. have been isolated from 50 samples of red chilli collected throughout the country. These 26 isolates were grown primarily on agar media to identify the aflatoxin producing species. It is possible to distinguish A. flavus strains from other Aspergillus sp. developing orange colour on the reverse of the plates. The Coconut Cream Agar (CCA) is used to detect aflatoxin producer strains having blue fluorescence when exposed to a UV-light. Several other media were used for morphological characteristics of Aspergillus sp. Out of 26 isolates, four isolates were confirmed as Aspergillus sp. These isolates were subjected to cross contamination with freshly ground, sterile maize and after 15 days of incubation the contaminated maize were analyzed by HPLC and found aflatoxin in each of the sample containing 186 ppb (max.). This study was conducted to assay the ability to produce aflatoxins by the Aspergillus spp. isolated from red chilli (Capsicum annuum L. Solanaceae) available throughout the country. The results found in the experiment are much more behind the acceptable limit according to some international standard. As red chilli is a widely used spice in Bangladesh, the proper controlling measures may be taken for controlling the surveillance of aflatoxinic fungi like as use of bio-pesticides, proper drying method and storage conditions.
Assessment of Different Traits to Evaluate Genetic Divergence in Some Wheat (Triticum aestivum L.) Genotypes under Late Sowing Condition  [PDF]
Md. Mukhtar Hossain, Md. Abul Kalam Azad, Touria El-Jaoual Eaton, Md. Nur-Alam Siddquie
American Journal of Plant Sciences (AJPS) , 2021, DOI: 10.4236/ajps.2021.125050
Abstract: The research work was undertaken to identify the extent of genetic diversity in different parameters of wheat related to heat tolerance mechanism. Performances of currently available 25 spring wheat genotypes were studied at the Regional Wheat Research Institute, Shyampur, Rajshahi during the winter season of 2016/2017. All these genotypes (25) were grouped into five clusters on the basis of non-hierarchical clustering parameters viz. cluster I (G2, G5, G6, G16, G20), II (G4, G7, G9, G11, G12, G17), III (G10, G24), IV (G1, G13, G19, G21) and V (G3, G8, G14, G15, G18, G22, G23, G25). These groups were arranged into five (5) pairs of clusters viz. cluster I and III; II and III; II and V; III and IV; IV and V considering their similar potentiality of different traits. Results revealed that the maximum number of genotypes (8) was found in cluster V while cluster III comprised minimum genotypes (2). The inter-cluster distance was higher than intra-cluster distances. The highest and second highest eigenvalues belonged to spike/m2 (25.23%) and spikelets/spike (20.18%) respectively, along with positive canonical values in both the vectors 1 and 2 for these two traits identified them as major traits by exposing their highest potential toward genetic divergence. Cluster III produced the highest spike/m2 (388.8), grain/spike (48.1), plant height (89.5 cm), SPAD (54.2), yield (2799 kg/ha) and biomass (7758.1 Kg/ha) with lowest heading days (64.7 days), maturity days (98.7 days), canopy temperature at vegetative stage (21.7°C) and canopy temperature at grain filling stage (22.4°C). In contrast, cluster V produced the lowest 1000-grain weight (30.4 g) and grain yield (2172 kg/ha) belonging to the highest canopy temperature at both stages (23.8°C and 24.7°C). However, results suggested that the genotypes G10 and G24 under
Copper and Mercury in Food, Biological and Pharmaceutical Samples: Spectrophotometric Estimation as Cu(DDTC)2  [PDF]
Mohammad Nasir Uddin, Nur Mostaq Shah, Mohammad Amzad Hossain, Md. Muzahidul Islam
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.513093
Abstract: An alternative spectrophotometric method was optimized and validated for the estimation of mercury using diethyldithiocarbamate (DDTC), a common reagent, widely used for the preconcentration and isolation of metal ions in complex matrices followed by their estimation by varied techniques. Diethyldithiocarbamate forms yellow Cu(DDTC)2 with copper and white Hg(DDTC)2 with mercury (having d10 system) which are extracted in CCl4. The UV-visible spectrum of Cu(DDTC)2 is very stable at pH 5.0 and has a maximum absorption (λmax) at 435 nm. Hg(DDTC)2 is more stable than Cu(DDTC)2. Estimation of mercury is based on a quantitative displacement of Cu(II) of Cu(DDTC)2 with the addition of mercury followed by the measurement of reduced absorbance. Primarily, method was optimized and validated for the estimation of copper. Therefore, simultaneous determination of Cu(II) and Hg(II) in mixture is proposed fractionating the extract. The molar specific coefficient (ε) for the mercury was 1.4 × 104 mol﹣1·L·cm﹣1 and for copper was 3.16 × 105 mol﹣1·L·cm﹣1 at 435 nm. The detection limits of Cu2+ and Hg2+ were 0.023 μg·mL﹣1 and 0.029 μg·mL﹣1, respectively. The calibration curve shows good linearity of 0.02 - 12.0 and 0.02 - 15.0 μg·mL﹣1 for the Cu2+ and Hg2+ determination, respectively. Proposed technique was applied to food, biological and pharmaceutical samples for the determination of Cu(II) and Hg(II).
Water Soluble Ionic Species in the Atmospheric Fine Particulate Matters (PM2.5) in a Southeast Asian Mega City (Dhaka, Bangladesh)  [PDF]
Abdus Salam, Md. Assaduzzaman, Muhammad Nobi Hossain, A. K. M. Nur Alam Siddiki
Open Journal of Air Pollution (OJAP) , 2015, DOI: 10.4236/ojap.2015.43010
Abstract: 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·m-3 during day time and 246.8 μg·m-3 during night time with a total average of 191.4 μg·m-3. 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·m-3) and about three times higher than DoE, Bangladesh (65.0 μg·m-3) 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·m
Edible Growth Medium: A New Window for Probiotic Research  [PDF]
Md. Nur Hossain, Annana Akter, Sanjida Humayan, Liton Chandra Mohanto, Shamima Begum, Monzur Morshed Ahmed
Advances in Microbiology (AiM) , 2020, DOI: 10.4236/aim.2020.102004
Abstract: Conventional growth media for microbes contains lots of non-edible components that are harmful to consume when the organism is ready to intake—like probiotics growing in chemical media (Lactobacillus grown in MRS media). The study was conducted to develop an edible and low-cost growth media that supports the growth of probiotics Lactic Acid bacteria for the enhancement of probiotic research. The 04 isolates of Lactobacillus (L. plantarum, L. rhamnosus, L. ferciminis and L. bifarmentans) and 02 Bifidobacterium (B. infantis and B. Bifidum) were used for the evaluation of medium efficacy. To formulate the edible culture media, 04 vegetables and 02 pulses were used. The media was formulated in different formulations. For Lactobacillus, maximum growth was observed at MM-2 media formulation that was about 15.62 log CFU/ml for L. plantarum and compared to MRS media that was 11.78 log CFU/ml. Bifidobaterium showed the highest viability at MW-1 edible media formulation which was about 12.72 log CFU/ml whereas in Bifidobacteria selective media the cell viability was 12.48 log CFU/ml. The edible media has no toxic or unhealthy effect on mice while trailing in an animal model and shows excellent results in encapsulation with alginate. In comparison with the performance of traditional chemical media, the formulated media were found to be cost-effective and safe for human consumption.
Brachyuran Crab Fauna Character Estimated from Marine Water of Bangladesh and Noted New Record (Crustacea: Decapoda) as Distribution  [PDF]
Nur Alam, Sanjay Chakraborty, Md. Muzammel Hossain, Mohammad Abdul Baki, Shayer Mahmood Ibney Alam, Chenhong Li
Open Journal of Marine Science (OJMS) , 2020, DOI: 10.4236/ojms.2020.104017
Abstract: As habitat and distribution, in the study a total of 18 crab species were identified, belonging to 10 families (Calappidae, Epialtidae, Gecarcinidae, Grapsidae, Matutidae, Ocypodidae, Panopeidae, Sesarmidae, Varunidae, and Xanthidae) order Decapoda under subphylum crustacean with relevant distinguish morphological and meristic character and geographical position. We investigated crab species of Bangladesh from December 2013 to October 2014. All species samples were collected by hand picking on a baseline survey in Saint Martin’s Island (the only coral island of Bangladesh) and adjacent marine water body of Bay of Bengal, Satkhira area (brackish and freshwater) and mangrove forest area (Sundarban). Among 18 species, 10 crab species from Family Epialtidae (1 species), Gecarcinidae (2 species), Ocypodidae (1 species), Panopeidae (1 species), Sesarmidae (1 species) and Xanthidae (4 species) were newly occurred in the Bay of Bengal, Bangladesh. Cardisoma armatum and Zosymus aeneus species were larger than other enlisted species.
Development of Fruit Dahi (Yoghurt) Fortified with Strawberry, Orange and Grapes Juice
Md. Nur Hossain,Md. Fakruddin,Md. Nurul Islam
American Journal of Food Technology , 2012,
Abstract: Dahi or yoghurt is the most popular milk product owing to its particular physical, nutritional, microbiological and organoleptic properties. The research was conducted to prepare fruit yoghurt fortified with different level of fruit juice (5, 10 and 15%) of different fruits (strawberry, orange and grape). Different physical, chemical and microbiological characteristics were analyzed to assay the quality of the yoghurts. Quality of the yoghurts was improved due to incorporation of low level of fruit juice. Yoghurts fortified with 10% orange juice was the best in quality among the others. The smell and taste, body and consistency and color and texture of the fruit yoghurts were equally acceptable. 10 and 15% strawberry fruit yoghurt contain more acid and its texture was cracked down in refrigeration temperature. The moisture and acidity content of fruit yoghurts were increased than plain yoghurt because of high content of these in the fruits. The fat, protein, carbohydrates and ash content of strawberry and orange fruit yoghurt were decreased than normal plain yoghurt. But the carbohydrates content of grape yoghurt were increased because grape contains more sugar than milk and other two fruits. Statistical analysis showed that yoghurt fortified with 10% orange juice was more acceptable than others comparing all quality characteristics. The microbiological quality of the fruit yoghurts was also acceptable because of acid content of the fruits. In case of strawberry yoghurt, fruit juice concentration more than 5% was not suitable for fruit yoghurt because that are highly acidic and curd was cracked down at refrigerated condition. The findings of this research may give an overall idea about manufacturing of fruit yoghurt incorporating different level of fruit juice and appropriate technology of fruit yoghurt preparation.
Effect of Chemical Additives on the Shelf Life of Tomato Juice
Md. Nur Hossain,Md. Fakruddin,Md. Nurul Islam
American Journal of Food Technology , 2011,
Abstract: Tomato (Lycopersicon esculentum Mill.) is one of the most popular and demanding vegetables grown in Bangladesh. The aim of this study was to assess the effect of chemical additives on the shelf life of tomato juice. Tomato juice was prepared with three different chemical additives namely Potassium meta-bisulphate (KMS), Sodium benzoate and sorbic acid. The shelf life of these tomato juices was studied for 60 days storage period. Chemical analysis and sensory tests were carried out during the 60 days at an interval of 15 days to assess the effect of chemical additives on the shelf life of tomato juice. Negligible change in chemical constituents except vitamin C was observed in the prepared juices throughout the 60 days storage period. Color was gradually faded and off-flavor developed at the end of the storage time at room temperature. Additives and storage period has significant effect on percent acidity. Tomato juice prepared with potassium meta bisulphate was spoiled after 45 days whereas, tomato juice prepared with sorbic acid was spoiled after 30 days of storage at room temperature. Tomato juice prepared with sodium benzoate was more stable than others and spoiled at the end of the 60 days storage period at room temperature. Total number of viable bacteria was highest in tomato juice with potassium meta bisulphate and tomato juice with sodium benzoate contained least viable bacteria. There were no significant difference among the juices with three different chemical additives in respect to color and acceptability. Considering all the parameters, sodium benzoate tends to be better additive than potassium meta bisulphate and sorbic acid for preservation of tomato juice.
Tests of Weak-form Market Efficiency of Dhaka Stock Exchange: Evidence from Bank Sector of Bangladesh
Md. Sogir Hossain Khandoker,Md. Nur Alam Siddik,Md Azam
Interdisciplinary Journal of Research in Business , 2011,
Abstract: This paper uses Random walk hypothesis to test market efficiency in the Dhaka Stock Exchange Ltd (DSE).In this paper; with Runs test, Dickey-Fuller Unit root test processed and analyzed the behavior of daily return of Dhaka Stock Market indices during the past 11 years. The sample includes the daily price indices of all securities listed on the DSE general, DSI (All Share), DSE top 20 indices, and Daily indices listed in the market. As a proxy of movement of individual stock prices, daily closing prices of 30 companies operating in the Bank sector has been analyzed. The results provide evidence that DSE does not follow the random walk model and so the Dhaka stock exchange (DSE) is not efficient even in weak form. To improve the capital market, the timely disclosure and dissemination of information to the shareholders and investors on the performance of the listed companies should be emphasized.
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