Amin Khan - Academia.edu (original) (raw)

Papers by Amin Khan

Research paper thumbnail of Towards Distributed Architecture for Collaborative Cloud Services in Community Networks

Research paper thumbnail of Somatic Mutation Screening: Identification of Individuals Harboring K-ras Mutations With the Use of Plasma DNA

Background: Many cancers are attributed to somatic mutation of DNA. We investigated whether it is... more Background: Many cancers are attributed to somatic mutation of DNA. We investigated whether it is feasible to detect cancer-associated somatic mutations in patients with neoplasms by using plasma DNA. Methods: Plasma samples were prospectively collected from 240 patients undergoing colonoscopy. Colorectal biopsies were performed as clinically indicated in 135 patients, and risk factor information was available from 232 patients. DNA was extracted from plasma and colorectal tissue and was amplified by use of a polymerase chain reaction method that enriches for mutations in codon 12 of the K-ras oncogene. Molecular, histologic, and clinical data were compared by use of two-sided Fisher's exact test. Results: Mutations in the K-ras gene detected in the plasma of 64 (28%) of 232 patients were statistically significantly associated with colorectal cancer risk factors (P = .0002). Of those patients having tissue available for comparison (n = 135), mutations in the K-ras gene were found in the tissues of 35 patients, and 29 (83%) of these 35 showed mutations in plasma samples. In contrast, the plasma assay was negative in 93 of the 100 patients whose tissue K-ras was wild-type. Among patients without biopsies (n = 105), 28 had mutated K-ras in their plasma DNA, despite the absence of remarkable colonoscopy findings; 24 of these 28 patients had risk factors for colorectal cancer. Overall, 25 (39%) of 64 patients showing mutations in plasma DNA had colorectal neoplasms with K-ras mutations compared with five (3%) of 176 patients without K-ras mutations in plasma DNA. Conclusion: Plasma DNA assays for the detection of mutations in K-ras codon 12 may provide a feasible method to screen populations for somatic mutations frequently found in neoplasms. The clinical utility of using this test in screening populations requires further study. [

Research paper thumbnail of Agroecology of onion couch (Arrhenathemm elatius var. bulbosum (Willd.))..: II. Competitiveness of onion couch in the crop situation, and how it influences development of onion couch or crop

Annals of Applied Biology, 1991

This study investigates the performance of vegetative propagules of onion couch (Arrhenatherum el... more This study investigates the performance of vegetative propagules of onion couch (Arrhenatherum elatius var. bulbosum) of varying sizes during the crop growth cycle; especially trends in tiller and bulb production and crop yield loss. The results suggest that the earlier the crop canopy closes the more suppression it will exert on the bulb formation stage of onion couch and hence its future reproductive potential. The closed canopy provided by a dense crop cut short the bulb formation phase and forced onion couch to invest more in aerial tillers in order to compete and coexist with the taller tillers of the crop. An additive experimental design used here to predict the crop losses indicated that natural infestation of onion couch caused greater crop yield loss compared to artificially planted plots. It was found that, although the regrowth from large aggregates with densely packed bulb chains is reduced by correlative dominance and density dependent mortality, presence of such large ...

Research paper thumbnail of A comparative study of growth strategies in two varieties of Arrhenatherum elatius

Plant Ecology, 1994

Growth strategies of the two varieties of Arrhenatherum elatius were studied. The two varieties s... more Growth strategies of the two varieties of Arrhenatherum elatius were studied. The two varieties studied were: onion couch, which produces bulbous swollen internodes and is an arable weed of local importance, whilst tall oat-grass is more widely distributed. An experiment in which the two varieties were grown at different densities in monoculture and were harvested at intervals, highlighted various aspects of the competitive relation between the two varieties and an annual crop. Significant and consistent differences were found between the two varieties for most of the attributes measured during the two growing seasons. Tall oat-grass allocated a greater proportion of its whole shoot dry weight to producing vigorous aerial tillers, whereas onion couch allocated a greater proportion of its whole shoot dry weight to the development of basal internodes. The regulation of tiller number as a reaction to increasing density in tall oat-grass is achieved by high tiller mortality, whereas in ...

Research paper thumbnail of Intellectual Property Rights and Technology Transfer to Developing Countries: a reassessment of the current debate

Research paper thumbnail of Synthesis, Characterization and Magnetic Study of mu-Oxamido-Bridged Copper (II)-Lanthanide (III) Heterobinuclear Complexes

The structural, morphological and magnetic properties of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 were... more The structural, morphological and magnetic properties of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 were studied using X-ray Diffraction (XRD), Scanning Electron Microcopy (SEM), and Superconductive Quantum Interference Device (SQUID). The sample was synthesized using sol gel method and sintered at 700, 800 and 900 o C. The crystallite size of the sample was influenced by the increase in the sintering temperature. There was no significant difference in magnetisation as sintering temperature increased from 700 o C to 800 o C, however, the magnetic properties of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 reduced drastically from 12.15 emu/g to 8.13 emu/g as sintering temperature increased from 800 o C to 900 o C. The surface of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 sintered at 900 o C was functionalised using ethyl 4-nitrobenzoate. The wavelength of the functionalised manganite was monitored using ultraviolet-visible spectrophotometre. Antimicrobial properties of the complex formed was investigated against the bacteria and fungi strains,

Research paper thumbnail of Effect of Vehicle Exhaust on the Quantity of Polycyclic Aromatic Hydrocarbons (PAHs) In Soil

Environmental monitoring and assessment, 2008

PAHs are formed during the incomplete combustion of organic substances containing carbon and hydr... more PAHs are formed during the incomplete combustion of organic substances containing carbon and hydrogen and are one of the first atmospheric pollutants identified as carcinogens. Most of the PAH environmental burden is found in the soil (95%). Soil samples collected from different roadsides were analyzed for seven polycyclic aromatic hydrocarbons (PAHs). The quantitative and qualitative analysis was carried out by UV Spectrophotometer. The individual PAH value ranged from 0.1 to 18.0 mg/kg. Phenenthrene and Pyrene were found to be the most abundant compounds. Vehicle emissions are the principal source of PAH in the Roadside soils. The highest concentration was found at site S2 (Hasthtnagri Roadside) which shows the highest traffic density.

Research paper thumbnail of Combining ability for yield and its components under heat stress in potato

CROP IMPROVEMENT-INDIA-, 2004

One of the objectives of this study was to estimate gene action and the type of inheritance of in... more One of the objectives of this study was to estimate gene action and the type of inheritance of investigated traits in cotton. Another objective was to evaluate general combining ability of parents and special combining ability of F1 diallel crosses and to select the superior F1s that can be used in future breeding programs of cotton. Additive and dominant components were found significant for investigated traits. Number of bolls and lint percentages were effective in the control of additive type of gene action with partial dominance, but seed-cotton yield was also effective in the control of additive type of gene action with over-dominance. Greater parents were 'Paum-15' and 'Stoneville-453' for the number of bolls and the seed-cotton yield; 'Stoneville-453' and 'Nazilli-84S' for the lint percentage.

Research paper thumbnail of Electromagnetic interference shielding effectiveness of carbon materials

Carbon

In this work, the effect of multi-walled carbon nanotube (MWCNT) on electromagnetic interference ... more In this work, the effect of multi-walled carbon nanotube (MWCNT) on electromagnetic interference shielding effectiveness (EMI SE) and mechanical properties of MWCNT-reinforced polypropylene (PP) nanocomposites were investigated with varying MWCNT content from 1 to 10 wt%. Electric resistance was tested using a 4-point-probe electric resistivity tester. The EMI SE of the nanocomposites was evaluated by means of the reflection and adsorption methods. The mechanical properties of the nanocomposites were studied through the critical stress intensity factor (K IC) measurement. The morphologies were observed by scanning electron microscopy (SEM). From the results, it was found that the EMI SE was enhanced with increasing MWCNT content, which played a key factor to determine the EMI SE. The K IC value was increased with increasing MWCNT content, whereas the value decreased above 5 wt% MWCNT content. This was probably considered that the MWCNT entangled with each other in PP due to an excess of MWCNT.

Research paper thumbnail of Towards Distributed Architecture for Collaborative Cloud Services in Community Networks

Research paper thumbnail of Somatic Mutation Screening: Identification of Individuals Harboring K-ras Mutations With the Use of Plasma DNA

Background: Many cancers are attributed to somatic mutation of DNA. We investigated whether it is... more Background: Many cancers are attributed to somatic mutation of DNA. We investigated whether it is feasible to detect cancer-associated somatic mutations in patients with neoplasms by using plasma DNA. Methods: Plasma samples were prospectively collected from 240 patients undergoing colonoscopy. Colorectal biopsies were performed as clinically indicated in 135 patients, and risk factor information was available from 232 patients. DNA was extracted from plasma and colorectal tissue and was amplified by use of a polymerase chain reaction method that enriches for mutations in codon 12 of the K-ras oncogene. Molecular, histologic, and clinical data were compared by use of two-sided Fisher's exact test. Results: Mutations in the K-ras gene detected in the plasma of 64 (28%) of 232 patients were statistically significantly associated with colorectal cancer risk factors (P = .0002). Of those patients having tissue available for comparison (n = 135), mutations in the K-ras gene were found in the tissues of 35 patients, and 29 (83%) of these 35 showed mutations in plasma samples. In contrast, the plasma assay was negative in 93 of the 100 patients whose tissue K-ras was wild-type. Among patients without biopsies (n = 105), 28 had mutated K-ras in their plasma DNA, despite the absence of remarkable colonoscopy findings; 24 of these 28 patients had risk factors for colorectal cancer. Overall, 25 (39%) of 64 patients showing mutations in plasma DNA had colorectal neoplasms with K-ras mutations compared with five (3%) of 176 patients without K-ras mutations in plasma DNA. Conclusion: Plasma DNA assays for the detection of mutations in K-ras codon 12 may provide a feasible method to screen populations for somatic mutations frequently found in neoplasms. The clinical utility of using this test in screening populations requires further study. [

Research paper thumbnail of Agroecology of onion couch (Arrhenathemm elatius var. bulbosum (Willd.))..: II. Competitiveness of onion couch in the crop situation, and how it influences development of onion couch or crop

Annals of Applied Biology, 1991

This study investigates the performance of vegetative propagules of onion couch (Arrhenatherum el... more This study investigates the performance of vegetative propagules of onion couch (Arrhenatherum elatius var. bulbosum) of varying sizes during the crop growth cycle; especially trends in tiller and bulb production and crop yield loss. The results suggest that the earlier the crop canopy closes the more suppression it will exert on the bulb formation stage of onion couch and hence its future reproductive potential. The closed canopy provided by a dense crop cut short the bulb formation phase and forced onion couch to invest more in aerial tillers in order to compete and coexist with the taller tillers of the crop. An additive experimental design used here to predict the crop losses indicated that natural infestation of onion couch caused greater crop yield loss compared to artificially planted plots. It was found that, although the regrowth from large aggregates with densely packed bulb chains is reduced by correlative dominance and density dependent mortality, presence of such large ...

Research paper thumbnail of A comparative study of growth strategies in two varieties of Arrhenatherum elatius

Plant Ecology, 1994

Growth strategies of the two varieties of Arrhenatherum elatius were studied. The two varieties s... more Growth strategies of the two varieties of Arrhenatherum elatius were studied. The two varieties studied were: onion couch, which produces bulbous swollen internodes and is an arable weed of local importance, whilst tall oat-grass is more widely distributed. An experiment in which the two varieties were grown at different densities in monoculture and were harvested at intervals, highlighted various aspects of the competitive relation between the two varieties and an annual crop. Significant and consistent differences were found between the two varieties for most of the attributes measured during the two growing seasons. Tall oat-grass allocated a greater proportion of its whole shoot dry weight to producing vigorous aerial tillers, whereas onion couch allocated a greater proportion of its whole shoot dry weight to the development of basal internodes. The regulation of tiller number as a reaction to increasing density in tall oat-grass is achieved by high tiller mortality, whereas in ...

Research paper thumbnail of Intellectual Property Rights and Technology Transfer to Developing Countries: a reassessment of the current debate

Research paper thumbnail of Synthesis, Characterization and Magnetic Study of mu-Oxamido-Bridged Copper (II)-Lanthanide (III) Heterobinuclear Complexes

The structural, morphological and magnetic properties of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 were... more The structural, morphological and magnetic properties of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 were studied using X-ray Diffraction (XRD), Scanning Electron Microcopy (SEM), and Superconductive Quantum Interference Device (SQUID). The sample was synthesized using sol gel method and sintered at 700, 800 and 900 o C. The crystallite size of the sample was influenced by the increase in the sintering temperature. There was no significant difference in magnetisation as sintering temperature increased from 700 o C to 800 o C, however, the magnetic properties of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 reduced drastically from 12.15 emu/g to 8.13 emu/g as sintering temperature increased from 800 o C to 900 o C. The surface of La 0.33 Ca 0.67 Mn 0.99 Fe 0.01 O 3 sintered at 900 o C was functionalised using ethyl 4-nitrobenzoate. The wavelength of the functionalised manganite was monitored using ultraviolet-visible spectrophotometre. Antimicrobial properties of the complex formed was investigated against the bacteria and fungi strains,

Research paper thumbnail of Effect of Vehicle Exhaust on the Quantity of Polycyclic Aromatic Hydrocarbons (PAHs) In Soil

Environmental monitoring and assessment, 2008

PAHs are formed during the incomplete combustion of organic substances containing carbon and hydr... more PAHs are formed during the incomplete combustion of organic substances containing carbon and hydrogen and are one of the first atmospheric pollutants identified as carcinogens. Most of the PAH environmental burden is found in the soil (95%). Soil samples collected from different roadsides were analyzed for seven polycyclic aromatic hydrocarbons (PAHs). The quantitative and qualitative analysis was carried out by UV Spectrophotometer. The individual PAH value ranged from 0.1 to 18.0 mg/kg. Phenenthrene and Pyrene were found to be the most abundant compounds. Vehicle emissions are the principal source of PAH in the Roadside soils. The highest concentration was found at site S2 (Hasthtnagri Roadside) which shows the highest traffic density.

Research paper thumbnail of Combining ability for yield and its components under heat stress in potato

CROP IMPROVEMENT-INDIA-, 2004

One of the objectives of this study was to estimate gene action and the type of inheritance of in... more One of the objectives of this study was to estimate gene action and the type of inheritance of investigated traits in cotton. Another objective was to evaluate general combining ability of parents and special combining ability of F1 diallel crosses and to select the superior F1s that can be used in future breeding programs of cotton. Additive and dominant components were found significant for investigated traits. Number of bolls and lint percentages were effective in the control of additive type of gene action with partial dominance, but seed-cotton yield was also effective in the control of additive type of gene action with over-dominance. Greater parents were 'Paum-15' and 'Stoneville-453' for the number of bolls and the seed-cotton yield; 'Stoneville-453' and 'Nazilli-84S' for the lint percentage.

Research paper thumbnail of Electromagnetic interference shielding effectiveness of carbon materials

Carbon

In this work, the effect of multi-walled carbon nanotube (MWCNT) on electromagnetic interference ... more In this work, the effect of multi-walled carbon nanotube (MWCNT) on electromagnetic interference shielding effectiveness (EMI SE) and mechanical properties of MWCNT-reinforced polypropylene (PP) nanocomposites were investigated with varying MWCNT content from 1 to 10 wt%. Electric resistance was tested using a 4-point-probe electric resistivity tester. The EMI SE of the nanocomposites was evaluated by means of the reflection and adsorption methods. The mechanical properties of the nanocomposites were studied through the critical stress intensity factor (K IC) measurement. The morphologies were observed by scanning electron microscopy (SEM). From the results, it was found that the EMI SE was enhanced with increasing MWCNT content, which played a key factor to determine the EMI SE. The K IC value was increased with increasing MWCNT content, whereas the value decreased above 5 wt% MWCNT content. This was probably considered that the MWCNT entangled with each other in PP due to an excess of MWCNT.