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Mohammed Mahabubur Rahman1,Md. Motiur Rahman,Mahbubul Alam 강원대학교 산림과학연구소 2010 Journal of Forest Science Vol.26 No.3
A study was conducted for indentifying the floral biodiversity of woody species by calculating four diversity indices using data collected from 4 stands of different age groups and disturbance regimes in two areas of Madhupur tract. Results showed that highest species diversity in the old growth secondary coppice forest (>60 years) under moderate anthropogenic disturbances of Madhupur National Park area (delete (D=0.74, Hʼ=3.36) followed by old growth secondary forest stands (>40 years) under moderate disturbances at Bhawal National Park area (D=0.65, Hʼ=2.81). Plant species diversity of the young enrichment plantations (<20 years and <15 years) under high anthropogenic disturbances in both the areas are much low (D=0.54 and Hʼ=2.16 and D=0.52 and Hʼ=1.92 respectively), which indicate high anthropogenic disturbances coupled with introduction of invasive exotics that are rival for endemic species are detrimental for conservation of biological diversity of tropical moist deciduous forests of Madhupur tract in Bangladesh.
Md. Mahabubur Rahman,Muhammad Nurul Amin,Futoshi Ishiguri,Shinso Yokota,Rubaiyat Sharmin Sultana,Yuya Takashima,Kazuya Iizuka,Nobuo Yoshizawa 한국식물생명공학회 2009 Plant biotechnology reports Vol.3 No.3
A plantlet regeneration protocol was developed on pot-grown mature plants of Elaeocarpus robustus Roxb. cv. Dwarf from nodal and leaf explants. The best yield of adventitious shoots was achieved from the leaf-derived calli in a modified MS (MMS1, half strength of major salts, full strength of minor salts, and vitamins) medium containing 4.0 lM BA ? 4.0 lM Kn ? 0.5 lM NAA ? 15% coconut water (CW). The shoot multiplication rate was amplified about twofold per culture after the addition of 15% CW to the medium. The rate of shoot multiplication reached maximum at the 5th subculture, and it maintained this rate throughout the 3 subsequent subcultures. The best rooting in vitro was investigated by subculturing the microcuttings in an MMS2 (half strength of both major salts and minor salts and full strength of vitamins) medium containing 1.0 lM IBA in the dark for one initial week at 30C, followed by subculturing them in a plant-growth regulator (PGR)-free medium in the light. The plantlets raised in vitro were successfully established under ex vitro conditions. A plantlet regeneration protocol was developed on pot-grown mature plants of Elaeocarpus robustus Roxb. cv. Dwarf from nodal and leaf explants. The best yield of adventitious shoots was achieved from the leaf-derived calli in a modified MS (MMS1, half strength of major salts, full strength of minor salts, and vitamins) medium containing 4.0 lM BA ? 4.0 lM Kn ? 0.5 lM NAA ? 15% coconut water (CW). The shoot multiplication rate was amplified about twofold per culture after the addition of 15% CW to the medium. The rate of shoot multiplication reached maximum at the 5th subculture, and it maintained this rate throughout the 3 subsequent subcultures. The best rooting in vitro was investigated by subculturing the microcuttings in an MMS2 (half strength of both major salts and minor salts and full strength of vitamins) medium containing 1.0 lM IBA in the dark for one initial week at 30C, followed by subculturing them in a plant-growth regulator (PGR)-free medium in the light. The plantlets raised in vitro were successfully established under ex vitro conditions.
Rahman, Mohammed Mahabubur,Tsukamoto, Jiro,Tokumoto, Yuji,Shuvo, Md. Ashikur Rahman Institute of Forest Science 2013 Journal of Forest Science Vol.29 No.1
Decomposition of plant material is an important component in the study of forest ecosystem because of its critical role in nutrient cycling. Different tree species has different nutrient release patterns, which are related to leaf litter quantitative traits and seasonal environmental factors. The quantitative traits of leaf litter are important predictors of decomposition and decomposition rates increase with greater nutrient availability in the forest ecosystems. At the ecosystem level, litter quantitative traits are most often related to the physical and chemical characteristics of the litter, for example, leaf toughness and leaf mass per unit area, and lignin content tannin and total phenolics. Thus, the analysis of litter quantitative traits and decomposition are highly important for the understanding of nutrient cycling in forest ecosystems. By studying the role of litter quantitative traits on decomposition and nutrient cycling in forest ecosystems will provide a valuable insight to how quantitative traits influence ecosystem nutrient dynamics. Such knowledge will contribute to future forest management and conservation practices.
Rahman, Mohammed Mahabubur,Rahman, Md. Motiur,Alam, Mahbubul Institute of Forest Science 2010 Journal of Forest Science Vol.26 No.3
A study was conducted for indentifying the floral biodiversity of woody species by calculating four diversity indices using data collected from 4 stands of different age groups and disturbance regimes in two areas of Madhupur tract. Results showed that highest species diversity in the old growth secondary coppice forest (>60 years) under moderate anthropogenic disturbances of Madhupur National Park area (delete (D=0.74, H'=3.36) followed by old growth secondary forest stands (>40 years) under moderate disturbances at Bhawal National Park area (D=0.65, H'=2.81). Plant species diversity of the young enrichment plantations (<20 years and <15 years) under high anthropogenic disturbances in both the areas are much low (D=0.54 and H'=2.16 and D=0.52 and H'=1.92 respectively), which indicate high anthropogenic disturbances coupled with introduction of invasive exotics that are rival for endemic species are detrimental for conservation of biological diversity of tropical moist deciduous forests of Madhupur tract in Bangladesh.
Sabuj Chandra Sutradhar,Md Mahabubur Rahman,Faiz Ahmed,류태욱,윤수진,이승찬,김재웅,이용훈,Yongcheng Jin,김환기 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-
Thermally and chemically stable sulfonated poly(phenylenebenzophenone)s (SPPBP) membranes havebeen synthesized from 1,4-dichloro-2,5-diphenylene methoxy benzophenone (PMBP) and 1,4-dichloro-2,5-dibenzoyl benzene (PBP) monomers by using Ni (0) catalyst for proton exchange membrane fuel cells(PEMFC). The synthesized SPPBP membranes exhibited ion exchange capacity from 1.18 to 2.30 meq/g.,water uptake from 34.2 to 78.3% and proton conductivity from 36.94 to 92.90 mS/cm. Additionally, the C–C coupling polymerization improved the thermal and chemical stability of the SPPBP membranes. Furthermore, the pendent benzophenone acid moiety provided the well hydrophilic/hydrophobic phaseseparation morphology with increased conductivity. Therefore, the SPPBP membranes can be a potentialcandidate for proton exchange membrane fuel cell (PEMFC).
U Venkatesh,Aravind Gandhi Periyasamy,Tasnim Ara,Md Mahabubur Rahman,Jugal Kishore 대한의료정보학회 2022 Healthcare Informatics Research Vol.28 No.2
Objectives: During the coronavirus disease 2019 (COVID-19) pandemic, countries around the world framed specific lawsand imposed varying degrees of lockdowns to ensure the maintenance of physical distancing. Understanding changes in temporaland spatial mobility patterns may provide insights into the dynamics of this infectious disease. Therefore, we assessedthe efficacy of lockdown measures in 16 countries worldwide by analyzing the relationship between community mobility patternsand the doubling time of COVID-19. Methods: We performed a retrospective record-based analysis of population-leveldata on the doubling time for COVID-19 and community mobility. The doubling time for COVID-19 was calculated basedon the laboratory-confirmed cases reported daily over the study period (from February 15 to May 2, 2020). Principal componentanalysis (PCA) of six mobility pattern-related variables was conducted. To explain the magnitude of the effect of mobilityon the doubling time, a finite linear distributed lag model was fitted. The k-means clustering approach was employed toidentify countries with similar patterns in the significant co-efficient of the mobility index, with the optimal number of clustersderived using Elbow’s method. Results: The countries analyzed had reduced mobility in commercial and social places. Reduced mobility had a significant and favorable association with the doubling time of COVID-19—specifically, the greaterthe mobility reduction, the longer the time taken for the COVID-19 cases to double. Conclusions: COVID-19 lockdownsachieved the immediate objective of mobility reduction in countries with a high burden of cases.
Yvonne Chow,Ruijiang Li,Jinchuan Wu,Sze Min Puah,Shu Wei New,Wei Qiang Chia,Felicia Lie,Talukder Md Mahabubur Rahman,Won Jae Choi 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4
The production of semi-synthetic beta-lactam antibiotics such as Amoxicillin may be performed enzymatically using penicillin acylase under mild conditions. However, the thermodynamically favored hydrolysis of the antibiotic product and the acyl donor substrate needs to be minimized to use the kinetically controlled route. The addition of cosolvents such as ethylene glycol and methanol (the two best solvents identified so far for semi-synthetic beta-lactam antibiotics) can achieve this to some degree, but these additives also produce enzyme inhibition and deactivation. In this study, we compared ethylene glycol and methanol under various substrate conditions. Methanol gave a better synthesis to hydrolysis ratio, although its deactivating effects adversely affected production at lower cosolvent concentrations than ethylene glycol. This effect and its dependence on substrate concentration was further modeled and optimized. A few targets of optimization such as Amoxicillin level, the synthesis to hydrolysis ratio, or a combination, were employed. While maximum levels of Amoxicillin synthesis were achievable only at high substrate concentrations, improvements derived from cosolvents were most significant at low substrate concentrations.
Chow, Yvonne,Li, Ruijiang,Wu, Jinchuan,Puah, Sze Min,New, Shu Wei,Chia, Wei Qiang,Lie, Felicia,Rahman, Talukder Md Mahabubur,Choi, Won-Jae Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4
The production of semi-synthetic beta-Iactam antibiotics such as Amoxicillin may be performed enzymatically using penicillin acylase under mild conditions. However, the thermodynamically favored hydrolysis of the antibiotic product and the acyl donor substrate needs to be minimized to use the kinetically controlled route. The addition of cosolvents such as ethylene glycol and methanol (the two best solvents identified so far for semi-synthetic beta-lactam antibiotics) can achieve this to some degree, but these additives also produce enzyme inhibition and deactivation. In this study, we compared ethylene glycol and methanol under various substrate conditions. Methanol gave a better synthesis to hydrolysis ratio, although its deactivating effects adversely affected production at lower cosolvent concentrations than ethylene glycol. This effect and its dependence on substrate concentration was further modeled and optimized. A few targets of optimization such as Amoxicillin level, the synthesis to hydrolysis ratio, or a combination, were employed. While maximum levels of Amoxicillin synthesis were achievable only at high substrate concentrations, improvements derived from cosolvents were most significant at low substrate concentrations.