Costus speciosus (J. Koenig) Sm., commonly known as crepe ginger, is primarily used as an ornamen... more Costus speciosus (J. Koenig) Sm., commonly known as crepe ginger, is primarily used as an ornamental plant worldwide. The aim of this research was to study the phytoconstituents of locally collected C. speciosus plant samples and test their antimicrobial effect against selected bacterial strains. Phytochemical analysis showed the presence of alkaloids, flavonoids, steroids, phenolic compounds, tannins, glycosides, and cardiac glycosides in the extracts. The extracts displayed variable degrees of antibacterial activity against the microorganisms in a bioautography experiment based on thin-layer chromatography. All the extracts showed activity against S. aureus, and none showed any activity against P. aeuroginosa. The ethanol and ethyl acetate extracts from the plant leaf and stem showed efficacy against S. typhi and B. subtilis, while the ethyl acetate extracts prevented the growth of S. pneumoniae. Only the ethanol extract from plant leaves had a negligible effect on K. pneumoniae. ...
Grammothele lineata, an endophyte isolated in our laboratory from jute (Corchorus olitorius acc. ... more Grammothele lineata, an endophyte isolated in our laboratory from jute (Corchorus olitorius acc. 2015) was found to be a substantial paclitaxel producer. Taxol and its related compounds, produced by this endophyte were extracted by growing the fungus in simple nutrient media (potato dextrose broth, PDB). Taxol was identified and characterized by different analytical techniques (TLC, HPLC, FTIR, LC-ESI-MS/MS) following its extraction by ethyl acetate. In PDB media, this fungus was found to produce 382.2 μgL-1 of taxol which is about 7.6 x103 fold higher than the first reported endophytic fungi, Taxomyces andreanae. The extracted taxol exhibited cytotoxic activity in an in vitro culture of HeLa cancer cell line. The fungal extract also exhibited antifungal and antibacterial activities against different pathogenic strains. This is the first report of a jute endophytic fungus harboring the capacity to produce taxol and also the first reported taxol producing species that belongs to the ...
The present study reveals an improved method for the evaluation of Adhatoda vasica extract by qua... more The present study reveals an improved method for the evaluation of Adhatoda vasica extract by quantitation of major metabolite vasicine. The plant powder was extracted with methanol and evaporated in vaccuo to obtain an oily residue. The residue was diluted with aqueous solution of citric acid (1%) and was further extracted with chloroform. The preliminary screening for alkaloid was done with alkaloidal reagents and the presence of vasicine was assessed by thin layer chromatography (TLC). The extractive was then subjected to column chromatography using a mixture of ethyl acetate and methanol adjusted to pH 9.5 with liquid ammonia as mobile phase. The TLC chromatograms of the collected column fractions were developed and the fractions indicated the presences of vasicine were combined together. The residue obtained from evaporation of solvent was subjected to preparative TLC along with reference standard to get pure crystalline vasicine. The compound vasicine was ascertained by UV-Vis, FT-IR and LCMS/MS analyses. The quantitative estimation of vasicine was carried out by reversed phase HPLC method. About 99.50% of pure vasicine (647 mg) compared to reference standard was obtained from 250 gm of leaf powder (0.2588% w/w).
Medicinal plants constitute an important component of flora and are widely distributed in Banglad... more Medicinal plants constitute an important component of flora and are widely distributed in Bangladesh. The pharmacological evaluation of substances from plants is an established method for the identification of lead compounds which shows the way to the development of novel and safe medicinal agents. Based on the ethnopharmacological literature two widely used medicinal plants Phyllanthus amarus and Monstera deliciosa were chosen to investigate their cytotoxicity through brine shrimp lethality bioassay which is simple, reliable and convenient method for assessment of bioactivity of medicinal plants. The plants were collected from their natural habitat, dried under shade and extracted with ethyl acetate. In this study, ethyl acetate extract of Phyllanthus amarus exhibited potent cytotoxicity with LC50 values of 9.15µg/ml and 20.16µg/ml of leaves and the whole plant respectively. Monstera deliciosa exhibited cytotoxicity with LC50 values of 36.60µg/ml and 300.4 µg/ml of leaves and branches respectively. From the result, it can be predicted that extractives of Phyllanthus amarus possess cytotoxic principles and showed significantly more potency than in leaves rather than whole plant. In case of Monstera deliciosa the extractives of leaves exhibited very mild mortality while the extractives of branches did not show considerable cytotoxicity.
The mulberry (Morus alba L.) root barks were extracted with 80% aqueous methanol at room temperat... more The mulberry (Morus alba L.) root barks were extracted with 80% aqueous methanol at room temperature. The concentrated extract was partitioned as ethyl acetate (EtOAc), n-BuOH, and H 2 O fractions. From the EtOAc fraction, five triterpenoids were isolated through the repeated silica gel and octadecyl SiO 2 column chromatographies. According to the results of physico-chemical and spectroscopic data including nuclear magnetic resonance, mass spectrometry, and infrared, the chemical structures of the triterpenoids were respectively determined as α-amyrin (1), α-acetyl amyrin (2), lupeol (3), betulinic acid (4), and glutinol (5). Compounds 1, 3, and 5 were isolated for the first time from the mulberry root bark.
Wendlandia tinctoria var. grandis (Roxb.) DC. (Family: Rubiaceae) is a semi-evergreen shrub distr... more Wendlandia tinctoria var. grandis (Roxb.) DC. (Family: Rubiaceae) is a semi-evergreen shrub distributed over tropical and subtropical Asia. The present research intended to explore the pharmacological potential of the stem extract of W. tinctoria, focusing on the antioxidant, hypoglycemic, and antidiarrheal properties, and to isolate various secondary metabolites as mediators of such activities. A total of eight phenolic compounds were isolated from the dichloromethane soluble fraction of the stem extract of this plant, which were characterized by electrospray ionization (ESI) mass spectrometric and 1H NMR spectroscopic data as liquiritigenin (1), naringenin (2), apigenin (3), kaempferol (4), glabridin (5), ferulic acid (6), 4-hydroxybenzoic acid (7), and 4-hydroxybenzaldehyde (8). The dichloromethane soluble fraction exhibited the highest phenolic content (289.87 ± 0.47 mg of GAE/g of dried extract) and the highest scavenging activity (IC50 = 18.83 ± 0.07 µg/mL) against the DPPH fr...
Commercial drinking water may serve as potential threat to public health if these items are conta... more Commercial drinking water may serve as potential threat to public health if these items are contaminated with a number of pathogenic microorganisms due to faulty manufacturing process. Present study attempted to isolate and quantify the microorganisms from various jar and bottle water samples collected from various areas of Dhaka city. Antibiotic susceptibility pattern of suspected bacterial isolates were also determined in this study. Out of the eighteen samples studied, ten were jar water samples and eight were bottled water samples. The range of total viable bacterial count (TVBC) in these samples ranged from 102 to 105 cfu/ml. Specific pathogens such as, Salmonella spp., Shigella spp., Vibrio spp. and fecal coliforms could not be found in these samples. However coliforms could be detected in 10 samples. The antibiogram study showed that all Escherichia coli and Klebsiella spp. isolates found from these samples were sensitive against gentamicin (10 μg) and azithromycin (30 μg). V...
Bangladesh Medical Research Council Bulletin, 2016
Silkworm, Bombyx mori, has passive immunity and can be infected by pathogenic bacteria. Therefore... more Silkworm, Bombyx mori, has passive immunity and can be infected by pathogenic bacteria. Therefore, it can be used as a robust bacterial infection model for screening of pathogenic isolates from various sources. In this work, 11 environmental, clinical and veterinary isolates were screened for pathogenicity using silkworm larvae by injecting bacterial suspension through their dorsal surface and observing response. Experimental conditions were established by using Bacillus thuringiensis SW_R_F_1, Escherichia coli O157:H7, E. coli DH5α and 0.6% saline. Nine out of 11 isolates were detected pathogenic after screening. The biochemical and genomic analysis of the nine test isolates confirmed their pathogenicity. The LD50 of Pseudomonas aeruginosa 47D and Salmonella Typhimurium 77 were 4.63×107 at 12 hours was 8.02×107 cells/100μl/gram at 24 hours respectively. These results indicated that silkworm exhibits differential pathological response for pathogenic and nonpathogenic bacteria, and c...
The antioxidant, antibacterial and cytotoxic properties of methanol extract of Urtica crenulata (... more The antioxidant, antibacterial and cytotoxic properties of methanol extract of Urtica crenulata (syn: Laportea crenulata Gaud) stem has been investigated in the present study. The antioxidant and cytotoxic activity of the Urtica crenulata methanol extract were assessed by DPPH free radical scavenging method and brine shrimp lethality bioassay method, respectively. The antibacterial activity of the plant extract (500 μg/disc) was also carried out by disc diffusion technique. Stem extract showed DPPH (2,2-diphenyl-1picrylhydrazyl) free radical scavenging effect compared with ascorbic acid. IC 50 value of ascorbic acid and stem extract was found 14.72 μg/ml and 1468.9 μg/ml, respectively. In antibacterial experiment, Urtica crenulata stem extract showed 8, 14 and 10 mm of diameter of zone inhibition against Salmonella typhi, Shigella flexneri and Shigella sonnei, respectively and 9 and 8 mm of diameter of zone inhibition against Bacillus subtilis and Bacillus cereus but no activity was observed against Staphylococcus aureus. In brine shrimp lethality assay, the LC 50 value of the extract was found 104.0 μg/ml, which indicates that the extract has high cytoxic effect. The present study demonstrates that methanol extract of Urtica crenulata stem has significant cytotoxic effect. The extract also showed some moderate antibacterial and minimum significant antioxidant effects.
This study was designed to investigate the antibacterial activities of alcohol extracts of Phoeni... more This study was designed to investigate the antibacterial activities of alcohol extracts of Phoenix dactylifera (date palm 'type Ajwa'), Nigella sativa (black cumin), Elettaria cardamomum (cardamom), Tinospora crispa (Akar patawali) and Panax ginseng (ginseng). The plant extracts were prepared with methanol and assayed for antibacterial activity against Methicillin-Resistant Staphylococcus Aureus (MRSA) and S. aureus. Extracts of N. sativa, E. cardamomum and P. ginseng produced maximum inhibition activities in the MRSA strain ATCC 33591, while T. crispa had the greatest activity in the strain ATCC 25923. The P. dactylifera extract had no effect on the tested bacteria. The growth inhibition was used to determine minimum inhibitory concentrations and minimum bactericidal concentrations. An in vivo experiment using the T. crispa ethanol extract in adult male and female Sprague Dawley rats (4 g kg −1 dose) showed low toxicity based on the LD 50 value.
Seven florally diversified Bangladeshi honey samples were assessed for their physicochemical prop... more Seven florally diversified Bangladeshi honey samples were assessed for their physicochemical properties as well as their antibiogram profile on different human pathogenic bacterial strains. The average density, total protein content, ascorbic acid content, total phenolics content and the total antioxidant capacity of these honeys were determined as 1.50±0.09 g/ml, 5.63±1.56 mg/g, 91.87±22.16 mg/g, 571.04±289.02 mg gallic acid equivalent/gram, and 320.74±55.06 mg ascorbic acid equivalent/gram of samples, respectively. A significant correlation between the phenolics content and the total antioxidant capacity was observed in commercially available honey samples. However, the natural honey samples showed the best antibacterial activity against different pathogenic multidrug-resistant bacterial strains. Significant antibacterial activities were observed against Klebsiella pneumoniae, Salmonella typhi, Micrococcus luteus, Pseudomonas spp. and Enterobacter spp. and moderate antibacterial a...
Here we report a jute endophyte Staphylococcus hominis strain MBL_AB63 isolated from jute seeds w... more Here we report a jute endophyte Staphylococcus hominis strain MBL_AB63 isolated from jute seeds which showed promising antimicrobial activity against Staphylococcus aureus SG511 when screening for antimicrobial substances. The whole genome sequence of this strain, annotated using BAGEL4 and antiSMASH 5.0 to predict the gene clusters for antimicrobial substances identified a novel antimicrobial peptide cluster that belongs to the class I lantibiotic group. The predicted lantibiotic (homicorcin) was found to be 82% similar to a reported peptide epicidin 280 having a difference of seven amino acids at several positions of the core peptide. Two distinct peaks obtained at close retention times from a RP-HPLC purified fraction have comparable antimicrobial activities and LC–MS revealed the molecular mass of these peaks to be 3046.5 and 3043.2 Da. The presence of an oxidoreductase (homO) similar to that of epicidin 280- associated eciO or epilancin 15X- associated elxO in the homicorcin ge...
Costus speciosus (J. Koenig) Sm., commonly known as crepe ginger, is primarily used as an ornamen... more Costus speciosus (J. Koenig) Sm., commonly known as crepe ginger, is primarily used as an ornamental plant worldwide. The aim of this research was to study the phytoconstituents of locally collected C. speciosus plant samples and test their antimicrobial effect against selected bacterial strains. Phytochemical analysis showed the presence of alkaloids, flavonoids, steroids, phenolic compounds, tannins, glycosides, and cardiac glycosides in the extracts. The extracts displayed variable degrees of antibacterial activity against the microorganisms in a bioautography experiment based on thin-layer chromatography. All the extracts showed activity against S. aureus, and none showed any activity against P. aeuroginosa. The ethanol and ethyl acetate extracts from the plant leaf and stem showed efficacy against S. typhi and B. subtilis, while the ethyl acetate extracts prevented the growth of S. pneumoniae. Only the ethanol extract from plant leaves had a negligible effect on K. pneumoniae. ...
Grammothele lineata, an endophyte isolated in our laboratory from jute (Corchorus olitorius acc. ... more Grammothele lineata, an endophyte isolated in our laboratory from jute (Corchorus olitorius acc. 2015) was found to be a substantial paclitaxel producer. Taxol and its related compounds, produced by this endophyte were extracted by growing the fungus in simple nutrient media (potato dextrose broth, PDB). Taxol was identified and characterized by different analytical techniques (TLC, HPLC, FTIR, LC-ESI-MS/MS) following its extraction by ethyl acetate. In PDB media, this fungus was found to produce 382.2 μgL-1 of taxol which is about 7.6 x103 fold higher than the first reported endophytic fungi, Taxomyces andreanae. The extracted taxol exhibited cytotoxic activity in an in vitro culture of HeLa cancer cell line. The fungal extract also exhibited antifungal and antibacterial activities against different pathogenic strains. This is the first report of a jute endophytic fungus harboring the capacity to produce taxol and also the first reported taxol producing species that belongs to the ...
The present study reveals an improved method for the evaluation of Adhatoda vasica extract by qua... more The present study reveals an improved method for the evaluation of Adhatoda vasica extract by quantitation of major metabolite vasicine. The plant powder was extracted with methanol and evaporated in vaccuo to obtain an oily residue. The residue was diluted with aqueous solution of citric acid (1%) and was further extracted with chloroform. The preliminary screening for alkaloid was done with alkaloidal reagents and the presence of vasicine was assessed by thin layer chromatography (TLC). The extractive was then subjected to column chromatography using a mixture of ethyl acetate and methanol adjusted to pH 9.5 with liquid ammonia as mobile phase. The TLC chromatograms of the collected column fractions were developed and the fractions indicated the presences of vasicine were combined together. The residue obtained from evaporation of solvent was subjected to preparative TLC along with reference standard to get pure crystalline vasicine. The compound vasicine was ascertained by UV-Vis, FT-IR and LCMS/MS analyses. The quantitative estimation of vasicine was carried out by reversed phase HPLC method. About 99.50% of pure vasicine (647 mg) compared to reference standard was obtained from 250 gm of leaf powder (0.2588% w/w).
Medicinal plants constitute an important component of flora and are widely distributed in Banglad... more Medicinal plants constitute an important component of flora and are widely distributed in Bangladesh. The pharmacological evaluation of substances from plants is an established method for the identification of lead compounds which shows the way to the development of novel and safe medicinal agents. Based on the ethnopharmacological literature two widely used medicinal plants Phyllanthus amarus and Monstera deliciosa were chosen to investigate their cytotoxicity through brine shrimp lethality bioassay which is simple, reliable and convenient method for assessment of bioactivity of medicinal plants. The plants were collected from their natural habitat, dried under shade and extracted with ethyl acetate. In this study, ethyl acetate extract of Phyllanthus amarus exhibited potent cytotoxicity with LC50 values of 9.15µg/ml and 20.16µg/ml of leaves and the whole plant respectively. Monstera deliciosa exhibited cytotoxicity with LC50 values of 36.60µg/ml and 300.4 µg/ml of leaves and branches respectively. From the result, it can be predicted that extractives of Phyllanthus amarus possess cytotoxic principles and showed significantly more potency than in leaves rather than whole plant. In case of Monstera deliciosa the extractives of leaves exhibited very mild mortality while the extractives of branches did not show considerable cytotoxicity.
The mulberry (Morus alba L.) root barks were extracted with 80% aqueous methanol at room temperat... more The mulberry (Morus alba L.) root barks were extracted with 80% aqueous methanol at room temperature. The concentrated extract was partitioned as ethyl acetate (EtOAc), n-BuOH, and H 2 O fractions. From the EtOAc fraction, five triterpenoids were isolated through the repeated silica gel and octadecyl SiO 2 column chromatographies. According to the results of physico-chemical and spectroscopic data including nuclear magnetic resonance, mass spectrometry, and infrared, the chemical structures of the triterpenoids were respectively determined as α-amyrin (1), α-acetyl amyrin (2), lupeol (3), betulinic acid (4), and glutinol (5). Compounds 1, 3, and 5 were isolated for the first time from the mulberry root bark.
Wendlandia tinctoria var. grandis (Roxb.) DC. (Family: Rubiaceae) is a semi-evergreen shrub distr... more Wendlandia tinctoria var. grandis (Roxb.) DC. (Family: Rubiaceae) is a semi-evergreen shrub distributed over tropical and subtropical Asia. The present research intended to explore the pharmacological potential of the stem extract of W. tinctoria, focusing on the antioxidant, hypoglycemic, and antidiarrheal properties, and to isolate various secondary metabolites as mediators of such activities. A total of eight phenolic compounds were isolated from the dichloromethane soluble fraction of the stem extract of this plant, which were characterized by electrospray ionization (ESI) mass spectrometric and 1H NMR spectroscopic data as liquiritigenin (1), naringenin (2), apigenin (3), kaempferol (4), glabridin (5), ferulic acid (6), 4-hydroxybenzoic acid (7), and 4-hydroxybenzaldehyde (8). The dichloromethane soluble fraction exhibited the highest phenolic content (289.87 ± 0.47 mg of GAE/g of dried extract) and the highest scavenging activity (IC50 = 18.83 ± 0.07 µg/mL) against the DPPH fr...
Commercial drinking water may serve as potential threat to public health if these items are conta... more Commercial drinking water may serve as potential threat to public health if these items are contaminated with a number of pathogenic microorganisms due to faulty manufacturing process. Present study attempted to isolate and quantify the microorganisms from various jar and bottle water samples collected from various areas of Dhaka city. Antibiotic susceptibility pattern of suspected bacterial isolates were also determined in this study. Out of the eighteen samples studied, ten were jar water samples and eight were bottled water samples. The range of total viable bacterial count (TVBC) in these samples ranged from 102 to 105 cfu/ml. Specific pathogens such as, Salmonella spp., Shigella spp., Vibrio spp. and fecal coliforms could not be found in these samples. However coliforms could be detected in 10 samples. The antibiogram study showed that all Escherichia coli and Klebsiella spp. isolates found from these samples were sensitive against gentamicin (10 μg) and azithromycin (30 μg). V...
Bangladesh Medical Research Council Bulletin, 2016
Silkworm, Bombyx mori, has passive immunity and can be infected by pathogenic bacteria. Therefore... more Silkworm, Bombyx mori, has passive immunity and can be infected by pathogenic bacteria. Therefore, it can be used as a robust bacterial infection model for screening of pathogenic isolates from various sources. In this work, 11 environmental, clinical and veterinary isolates were screened for pathogenicity using silkworm larvae by injecting bacterial suspension through their dorsal surface and observing response. Experimental conditions were established by using Bacillus thuringiensis SW_R_F_1, Escherichia coli O157:H7, E. coli DH5α and 0.6% saline. Nine out of 11 isolates were detected pathogenic after screening. The biochemical and genomic analysis of the nine test isolates confirmed their pathogenicity. The LD50 of Pseudomonas aeruginosa 47D and Salmonella Typhimurium 77 were 4.63×107 at 12 hours was 8.02×107 cells/100μl/gram at 24 hours respectively. These results indicated that silkworm exhibits differential pathological response for pathogenic and nonpathogenic bacteria, and c...
The antioxidant, antibacterial and cytotoxic properties of methanol extract of Urtica crenulata (... more The antioxidant, antibacterial and cytotoxic properties of methanol extract of Urtica crenulata (syn: Laportea crenulata Gaud) stem has been investigated in the present study. The antioxidant and cytotoxic activity of the Urtica crenulata methanol extract were assessed by DPPH free radical scavenging method and brine shrimp lethality bioassay method, respectively. The antibacterial activity of the plant extract (500 μg/disc) was also carried out by disc diffusion technique. Stem extract showed DPPH (2,2-diphenyl-1picrylhydrazyl) free radical scavenging effect compared with ascorbic acid. IC 50 value of ascorbic acid and stem extract was found 14.72 μg/ml and 1468.9 μg/ml, respectively. In antibacterial experiment, Urtica crenulata stem extract showed 8, 14 and 10 mm of diameter of zone inhibition against Salmonella typhi, Shigella flexneri and Shigella sonnei, respectively and 9 and 8 mm of diameter of zone inhibition against Bacillus subtilis and Bacillus cereus but no activity was observed against Staphylococcus aureus. In brine shrimp lethality assay, the LC 50 value of the extract was found 104.0 μg/ml, which indicates that the extract has high cytoxic effect. The present study demonstrates that methanol extract of Urtica crenulata stem has significant cytotoxic effect. The extract also showed some moderate antibacterial and minimum significant antioxidant effects.
This study was designed to investigate the antibacterial activities of alcohol extracts of Phoeni... more This study was designed to investigate the antibacterial activities of alcohol extracts of Phoenix dactylifera (date palm 'type Ajwa'), Nigella sativa (black cumin), Elettaria cardamomum (cardamom), Tinospora crispa (Akar patawali) and Panax ginseng (ginseng). The plant extracts were prepared with methanol and assayed for antibacterial activity against Methicillin-Resistant Staphylococcus Aureus (MRSA) and S. aureus. Extracts of N. sativa, E. cardamomum and P. ginseng produced maximum inhibition activities in the MRSA strain ATCC 33591, while T. crispa had the greatest activity in the strain ATCC 25923. The P. dactylifera extract had no effect on the tested bacteria. The growth inhibition was used to determine minimum inhibitory concentrations and minimum bactericidal concentrations. An in vivo experiment using the T. crispa ethanol extract in adult male and female Sprague Dawley rats (4 g kg −1 dose) showed low toxicity based on the LD 50 value.
Seven florally diversified Bangladeshi honey samples were assessed for their physicochemical prop... more Seven florally diversified Bangladeshi honey samples were assessed for their physicochemical properties as well as their antibiogram profile on different human pathogenic bacterial strains. The average density, total protein content, ascorbic acid content, total phenolics content and the total antioxidant capacity of these honeys were determined as 1.50±0.09 g/ml, 5.63±1.56 mg/g, 91.87±22.16 mg/g, 571.04±289.02 mg gallic acid equivalent/gram, and 320.74±55.06 mg ascorbic acid equivalent/gram of samples, respectively. A significant correlation between the phenolics content and the total antioxidant capacity was observed in commercially available honey samples. However, the natural honey samples showed the best antibacterial activity against different pathogenic multidrug-resistant bacterial strains. Significant antibacterial activities were observed against Klebsiella pneumoniae, Salmonella typhi, Micrococcus luteus, Pseudomonas spp. and Enterobacter spp. and moderate antibacterial a...
Here we report a jute endophyte Staphylococcus hominis strain MBL_AB63 isolated from jute seeds w... more Here we report a jute endophyte Staphylococcus hominis strain MBL_AB63 isolated from jute seeds which showed promising antimicrobial activity against Staphylococcus aureus SG511 when screening for antimicrobial substances. The whole genome sequence of this strain, annotated using BAGEL4 and antiSMASH 5.0 to predict the gene clusters for antimicrobial substances identified a novel antimicrobial peptide cluster that belongs to the class I lantibiotic group. The predicted lantibiotic (homicorcin) was found to be 82% similar to a reported peptide epicidin 280 having a difference of seven amino acids at several positions of the core peptide. Two distinct peaks obtained at close retention times from a RP-HPLC purified fraction have comparable antimicrobial activities and LC–MS revealed the molecular mass of these peaks to be 3046.5 and 3043.2 Da. The presence of an oxidoreductase (homO) similar to that of epicidin 280- associated eciO or epilancin 15X- associated elxO in the homicorcin ge...
Uploads
Papers by M Aftab Uddin