Publications by authors named "Md Nurul Amin"

13 Publications

  • Page 1 of 1

Pre hospital delay and its associated factors in acute myocardial infarction in a developing country.

PLoS One 2021 24;16(11):e0259979. Epub 2021 Nov 24.

Department of Cardiology, Ibrahim Cardiac Hospital and Research Institute, Dhaka, Bangladesh.

Background: Early revascularization and treatment is key to improving clinical outcomes and reducing mortality in acute myocardial infarction (AMI). In low- and middle-income countries such as Bangladesh, timely management of AMI is challenging, with pre-hospital delays playing a significant role. This study was designed to investigate pre-hospital delay and its associated factors among patients presenting with AMI in the capital city of Dhaka.

Methods: This retrospective cohort study was conducted on 333 patients presenting with AMI over a 3-month period at two of the largest primary reperfusion-capable tertiary cardiac care centres in Dhaka. Of the total patients, 239(71.8%) were admitted in the National Institute of Cardiovascular Diseases, Dhaka and 94(28.2%) at Ibrahim Cardiac Hospital & Research Institute, Dhaka Data were collected from patients by semi-structured interview and hospital medical records. Pre-hospital delay (median and inter-quartile range) was calculated. Statistical significance was determined by Chi-square test. Multivariate logistic regression analysis was done to determine the independent predictors of pre-hospital delay.

Results: The mean age of the respondents was 53.8±11.2 years. Two-thirds (67.6%) of the respondents were males. Median total pre-hospital delay was 11.5 (IQR-18.3) hours with median decision time from symptom onset to seeking medical care being 3.0 (IQR: 11.0) hours. Nearly half (48.9%) of patients presented to the hospital more than 12 hours after symptom onset. On multivariate logistic regression analysis, AMI patients with absence of typical chest pain [OR 5.21; (95% CI: 2.5-9.9)], diabetes [OR: 1.7 (95% CI: 1.0-2.9)], residing/staying > 30 km away from nearest hospital at the time of onset [OR: 4.3(95% CI = 2.3-7.2)] and belonged to lower and middle class [OR: 1.9(95% CI = 1.0-3.5)] were significantly associated with pre-hospital delays.

Conclusion: Acute myocardial infarction (AMI) patients with atypical chest pain, diabetes, staying far away from nearest hospital and belonged to lower and middle socioeconomic strata were significantly associated with pre-hospital delays. The findings could have immense implications for improvements about timely reaching of AMI patients to the hospital within the context of their sociodemographic status and geographic barriers of the city.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0259979PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8612565PMC
November 2021

The importance of farmers' perceptions of salinity and adaptation strategies for ensuring food security: Evidence from the coastal rice growing areas of Bangladesh.

Sci Total Environ 2020 Jul 13;727:138674. Epub 2020 Apr 13.

School of Environmental and Rural Science, University of New England, Australia.

Coastal salinity causes substantial adverse impacts on agricultural productivity and food security. Farmers' choice of salinity adaptation strategies might depend on how they perceive the problem. This research examined rice farmers' perceptions of salinity, adaptation strategies, and its implications for policy initiatives to sustain rice production in the affected coastal areas of Bangladesh. Boro rice growers (n = 109) randomly selected from two coastal sub-districts were interviewed using a semi-structured survey. Awareness of salinity and its increase over the past 20 years was widespread among rice farmers. A high proportion of farmers (90%) perceived the reproductive (e.g. booting, heading, and flowering) stages of the rice plant as the most sensitive to salinity problems. Salinity (ECe) was measured in the farmers' fields and were categorized according to farmers' perceptions and scientific interpretation (e.g. high or low). Farmers perceived a field affected by high salinity at a lower EC reading than the scientific interpretation of the salinity level. Most of the farmers (67%) were undertaking early transplanting and applying irrigation in order to adapt to salinity problems which occur later in rice crop growth during Boro season. Thus, farmers' actions demonstrated that their perceptions of salinity and adaptation responses were pre-emptive of when salinity was most likely to have an impact on the rice crop. Farmers' perceptions of salinization and measures to manage salinity need to be considered in research prioritization and policy formulation by the government. This action could potentially secure rice production and thus contribute to the achievement of Sustainable Development Goals (SDG-1, 2 and 3).
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http://dx.doi.org/10.1016/j.scitotenv.2020.138674DOI Listing
July 2020

Dissecting the Genetic Architecture of Aphanomyces Root Rot Resistance in Lentil by QTL Mapping and Genome-Wide Association Study.

Int J Mol Sci 2020 Mar 20;21(6). Epub 2020 Mar 20.

USDA-ARS Grain Legume Genetics and Physiology Research Unit, Pullman, WA 99164, USA.

Lentil ( Medikus) is an important source of protein for people in developing countries. Aphanomyces root rot (ARR) has emerged as one of the most devastating diseases affecting lentil production. In this study, we applied two complementary quantitative trait loci (QTL) analysis approaches to unravel the genetic architecture underlying this complex trait. A recombinant inbred line (RIL) population and an association mapping population were genotyped using genotyping by sequencing (GBS) to discover novel single nucleotide polymorphisms (SNPs). QTL mapping identified 19 QTL associated with ARR resistance, while association mapping detected 38 QTL and highlighted accumulation of favorable haplotypes in most of the resistant accessions. Seven QTL clusters were discovered on six chromosomes, and 15 putative genes were identified within the QTL clusters. To validate QTL mapping and genome-wide association study (GWAS) results, expression analysis of five selected genes was conducted on partially resistant and susceptible accessions. Three of the genes were differentially expressed at early stages of infection, two of which may be associated with ARR resistance. Our findings provide valuable insight into the genetic control of ARR, and genetic and genomic resources developed here can be used to accelerate development of lentil cultivars with high levels of partial resistance to ARR.
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http://dx.doi.org/10.3390/ijms21062129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7139309PMC
March 2020

A systematic review of soil carbon management in Australia and the need for a social-ecological systems framework.

Sci Total Environ 2020 Jun 21;719:135182. Epub 2019 Nov 21.

School of Environmental and Rural Science, University of New England, Australia.

Research efforts, on soil carbon management in agricultural lands, over the last two decades have sought to improve our understanding in order to increase soil productivity, soil carbon sequestration and to offset greenhouse gas emissions. This systematic review aims to identify the research gaps and future direction of soil carbon management in Australia. We explored and synthesized the use of social-ecological systems (SES) both in the global and Australian context, before making the first attempt to develop a conceptual SES framework for soil carbon management. Both quantitative and qualitative assessment of articles were used to identify and synthesise research trends, challenges and opportunities for improved soil carbon management. The results provide valuable insight into the SES components examined, the research gaps and the methodological challenges for research into soil carbon management conducted over the last two decades. The review revealed that research has predominately focused on the ecological component of soil carbon management in agricultural practices and has been conducted from a scientist's perspective. The sustainability of carbon-building soil management practices will require integration of social components into future research, particularly from a farmer perspective. The proposed conceptual SES framework is designed to identify and investigate SES components in soil carbon management in order to increase the process of offsetting greenhouse gas emissions as required by Sustainable Development Goals 2, 13 and 15.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135182DOI Listing
June 2020

Quality control methods for linear accelerator radiation and mechanical axes alignment.

Med Phys 2018 Jun 3;45(6):2388-2398. Epub 2018 May 3.

Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON, M5G 2M9, Canada.

Purpose: The delivery accuracy of highly conformal dose distributions generated using intensity modulation and collimator, gantry, and couch degrees of freedom is directly affected by the quality of the alignment between the radiation beam and the mechanical axes of a linear accelerator. For this purpose, quality control (QC) guidelines recommend a tolerance of ±1 mm for the coincidence of the radiation and mechanical isocenters. Traditional QC methods for assessment of radiation and mechanical axes alignment (based on pointer alignment) are time consuming and complex tasks that provide limited accuracy. In this work, an automated test suite based on an analytical model of the linear accelerator motions was developed to streamline the QC of radiation and mechanical axes alignment.

Methods: The proposed method used the automated analysis of megavoltage images of two simple task-specific phantoms acquired at different linear accelerator settings to determine the coincidence of the radiation and mechanical isocenters. The sensitivity and accuracy of the test suite were validated by introducing actual misalignments on a linear accelerator between the radiation axis and the mechanical axes using both beam steering and mechanical adjustments of the gantry and couch.

Results: The validation demonstrated that the new QC method can detect sub-millimeter misalignment between the radiation axis and the three mechanical axes of rotation. A displacement of the radiation source of 0.2 mm using beam steering parameters was easily detectable with the proposed collimator rotation axis test. Mechanical misalignments of the gantry and couch rotation axes of the same magnitude (0.2 mm) were also detectable using the new gantry and couch rotation axis tests. For the couch rotation axis, the phantom and test design allow detection of both translational and tilt misalignments with the radiation beam axis. For the collimator rotation axis, the test can isolate the misalignment between the beam radiation axis and the mechanical collimator rotation axis from the impact of field size asymmetry. The test suite can be performed in a reasonable time (30-35 min) due to simple phantom setup, prescription-based beam delivery, and automated image analysis. As well, it provides a clear description of the relationship between axes. After testing the sensitivity of the test suite to beam steering and mechanical errors, the results of the test suite were used to reduce the misalignment errors of the linac to less than 0.7-mm radius for all axes.

Conclusions: The proposed test suite offers sub-millimeter assessment of the coincidence of the radiation and mechanical isocenters and the test automation reduces complexity with improved efficiency. The test suite results can be used to optimize the linear accelerator's radiation to mechanical isocenter alignment by beam steering and mechanical adjustment of gantry and couch.
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http://dx.doi.org/10.1002/mp.12910DOI Listing
June 2018

Human waste: An underestimated source of nutrient pollution in coastal seas of Bangladesh, India and Pakistan.

Mar Pollut Bull 2017 May 24;118(1-2):131-140. Epub 2017 Feb 24.

Environmental Systems Analysis Group, Wageningen University and Research, The Netherlands.

Many people practice open defecation in south Asia. As a result, lot of human waste containing nutrients such as nitrogen (N) and phosphorus (P) enter rivers. Rivers transport these nutrients to coastal waters, resulting in marine pollution. This source of nutrient pollution is, however, ignored in many nutrient models. We quantify nutrient export by large rivers to coastal seas of Bangladesh, India and Pakistan, and the associated eutrophication potential in 2000 and 2050. Our new estimates for N and P inputs from human waste are one to two orders of magnitude higher than earlier model calculations. This leads to higher river export of nutrients to coastal seas, increasing the risk of coastal eutrophication potential (ICEP). The newly calculated future ICEP, for instance, Godavori river is 3 times higher than according to earlier studies. Our modeling approach is simple and transparent and can easily be applied to other data-poor basins.
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http://dx.doi.org/10.1016/j.marpolbul.2017.02.045DOI Listing
May 2017

Multileaf collimator performance monitoring and improvement using semiautomated quality control testing and statistical process control.

Med Phys 2014 Dec;41(12):121713

Radiation Medicine Program, Princess Margaret Cancer Center, Toronto, Ontario M5G 2M9, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 3E2, Canada; and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 1L7, Canada.

Purpose: High-quality radiation therapy using highly conformal dose distributions and image-guided techniques requires optimum machine delivery performance. In this work, a monitoring system for multileaf collimator (MLC) performance, integrating semiautomated MLC quality control (QC) tests and statistical process control tools, was developed. The MLC performance monitoring system was used for almost a year on two commercially available MLC models. Control charts were used to establish MLC performance and assess test frequency required to achieve a given level of performance. MLC-related interlocks and servicing events were recorded during the monitoring period and were investigated as indicators of MLC performance variations.

Methods: The QC test developed as part of the MLC performance monitoring system uses 2D megavoltage images (acquired using an electronic portal imaging device) of 23 fields to determine the location of the leaves with respect to the radiation isocenter. The precision of the MLC performance monitoring QC test and the MLC itself was assessed by detecting the MLC leaf positions on 127 megavoltage images of a static field. After initial calibration, the MLC performance monitoring QC test was performed 3-4 times/week over a period of 10-11 months to monitor positional accuracy of individual leaves for two different MLC models. Analysis of test results was performed using individuals control charts per leaf with control limits computed based on the measurements as well as two sets of specifications of ± 0.5 and ± 1 mm. Out-of-specification and out-of-control leaves were automatically flagged by the monitoring system and reviewed monthly by physicists. MLC-related interlocks reported by the linear accelerator and servicing events were recorded to help identify potential causes of nonrandom MLC leaf positioning variations.

Results: The precision of the MLC performance monitoring QC test and the MLC itself was within ± 0.22 mm for most MLC leaves and the majority of the apparent leaf motion was attributed to beam spot displacements between irradiations. The MLC QC test was performed 193 and 162 times over the monitoring period for the studied units and recalibration had to be repeated up to three times on one of these units. For both units, rate of MLC interlocks was moderately associated with MLC servicing events. The strongest association with the MLC performance was observed between the MLC servicing events and the total number of out-of-control leaves. The average elapsed time for which the number of out-of-specification or out-of-control leaves was within a given performance threshold was computed and used to assess adequacy of MLC test frequency.

Conclusions: A MLC performance monitoring system has been developed and implemented to acquire high-quality QC data at high frequency. This is enabled by the relatively short acquisition time for the images and automatic image analysis. The monitoring system was also used to record and track the rate of MLC-related interlocks and servicing events. MLC performances for two commercially available MLC models have been assessed and the results support monthly test frequency for widely accepted ± 1 mm specifications. Higher QC test frequency is however required to maintain tighter specification and in-control behavior.
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http://dx.doi.org/10.1118/1.4901520DOI Listing
December 2014

Levels of heavy metals in tissues of shingi fish (Heteropneustes fossilis) from Buriganga River, Bangladesh.

Environ Monit Assess 2013 Jul 8;185(7):5461-9. Epub 2012 Nov 8.

Department of Zoology, University of Dhaka, Dhaka, 1000, Bangladesh.

Heavy metal pollution was reported in commercially valuable freshwater edible fish in the Buriganga River, Bangladesh. The concentrations of As, Pb, Cd, Cr, Zn, and Cu were investigated in the muscle, gill, stomach, intestine, and liver of Heteropneustes fossilis caught at three stations to assess the degree of fish pollution by heavy metals. Significant differences in concentrations of analyzed elements were observed among different tissues, but not among the stations. The ranges of the measured concentrations (μg/g dry weight) in the tissues of H. fossilis were as follows: arsenic concentration was (0.2-0.4), (0.82-0.90), (3.29-3.99), (2.20-2.80), and (2.41-2.90), that of lead was (1.79-2.20), (4.95-6.55), (10.36-13.38), (5.74-9.70), and (18.20-18.79), that of cadmium was (0.3-0.4), (2.87-4.27), (1.03-1.63), (1.55-4.59), and (2.25-5.50), that of chromium was (1.40-1.70), (3.52-3.72), (2.28-5.29), (2.77-3.79), and (4.25-8.65), that of zinc was (24.47-28.82), (16.82-18.80), (20.22-22.20), (22.86-26.68), and (60.82-67.80), and that of copper was (7.80-8.50), (6.22-6.81), (38.21-44.25), (17.07-21.03), and (43.24-47.30) in the muscle, gill, stomach, intestine, and liver, respectively. This research showed that the liver appeared to be the main heavy metal storage tissue, while the muscle had the lowest levels of analyzed metals. The concentrations of metal in the muscles not exceeded the acceptable levels for a food source for human consumption.
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http://dx.doi.org/10.1007/s10661-012-2959-4DOI Listing
July 2013

Small field electron beam dosimetry using MOSFET detector.

J Appl Clin Med Phys 2010 Oct 4;12(1):3267. Epub 2010 Oct 4.

Department of Radiation Physics, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.

The dosimetry of very small electron fields can be challenging due to relative shifts in percent depth-dose curves, including the location of dmax, and lack of lateral electronic equilibrium in an ion chamber when placed in the beam. Conventionally a small parallel plate chamber or film is utilized to perform small field electron beam dosimetry. Since modern radiotherapy departments are becoming filmless in favor of electronic imaging, an alternate and readily available clinical dosimeter needs to be explored. We have studied the performance of MOSFET as a relative dosimeter in small field electron beams. The reproducibility, linearity and sensitivity of a high-sensitivity microMOSFET were investigated for clinical electron beams. In addition, the percent depth doses, output factors and profiles have been measured in a water tank with MOSFET and compared with those measured by an ion chamber for a range of field sizes from 1 cm diameter to 10 cm × 10 cm for 6, 12, 16 and 20 MeV beams. Similar comparative measurements were also per-formed with MOSFET and films in solid water phantom. The MOSFET sensitivity was found to be practically constant over the range of field sizes investigated. The dose response was found to be linear and reproducible (within ± 1% for 100 cGy). An excellent agreement was observed among the central axis depth dose curves measured using MOSFET, film and ion chamber. The output factors measured with MOSFET for small fields agreed to within 3% with those measured by film dosimetry. Overall results indicate that MOSFET can be utilized to perform dosimetry for small field electron beam.
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http://dx.doi.org/10.1120/jacmp.v12i1.3267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718583PMC
October 2010

Determination of silver in environmental samples by tungsten wire preconcentration method-electrothermal atomic absorption spectrometry.

Talanta 2004 Apr;62(5):1047-50

Department of Chemistry for Materials, Faculty of Engineering, Mie University, Tsu, Mie 514-8507, Japan.

A preconcentration method for silver in environmental waters involving adsorption on a tungsten wire, followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The optimal immersing time was 90s. The best pH for the adsorption of silver was 3. Under the optimal conditions, the detection limit for silver by the tungsten wire preconcentration method was 5.0ngl(-1) (3S/N) and the relative standard deviation was 8.2%. The effects of large amounts of concomitants on the preconcentration of silver were evaluated. Even though 10(3)- to 10(4)-fold excess of matrix elements existed in water, the silver response was not significantly affected by the matrix elements. The method with preconcentration on a tungsten wire was applied to the determination of silver in waters and proved to be sensitive, simple, and convenient. This adsorption method can be utilized in in situ sampling of ultra-trace silver in environmental samples (waters). Furthermore, after sampling it is easy to carry and store the tungsten wire without contamination for a long time.
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http://dx.doi.org/10.1016/j.talanta.2003.10.035DOI Listing
April 2004

Image guided IMRT dosimetry using anatomy specific MOSFET configurations.

J Appl Clin Med Phys 2008 Jun 23;9(3):69-81. Epub 2008 Jun 23.

Department of Radiation Physics, Princess Margaret Hospital, University Health Network, Toronto, Ontario, Canada.

We have investigated the feasibility of using a set of multiple MOSFETs in conjunction with the mobile MOSFET wireless dosimetry system, to perform a comprehensive and efficient quality assurance (QA) of IMRT plans. Anatomy specific MOSFET configurations incorporating 5 MOSFETs have been developed for a specially designed IMRT dosimetry phantom. Kilovoltage cone beam computed tomography (kV CBCT) imaging was used to increase the positional precision and accuracy of the detectors and phantom, and so minimize dosimetric uncertainties in high dose gradient regions. The effectiveness of the MOSFET based dose measurements was evaluated by comparing the corresponding doses measured by an ion chamber. For 20 head and neck IMRT plans the agreement between the MOSFET and ionization chamber dose measurements was found to be within -0.26 +/- 0.88% and 0.06 +/- 1.94% (1 sigma) for measurement points in the high dose and low dose respectively. A precision of 1 mm in detector positioning was achieved by using the X-Ray Volume Imaging (XVI) kV CBCT system available with the Elekta Synergy Linear Accelerator. Using the anatomy specific MOSFET configurations, simultaneous measurements were made at five strategically located points covering high dose and low dose regions. The agreement between measurements and calculated doses by the treatment planning system for head and neck and prostate IMRT plans was found to be within 0.47 +/- 2.45%. The results indicate that a cylindrical phantom incorporating multiple MOSFET detectors arranged in an anatomy specific configuration, in conjunction with image guidance, can be utilized to perform a comprehensive and efficient quality assurance of IMRT plans.
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http://dx.doi.org/10.1120/jacmp.v9i3.2798DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5722303PMC
June 2008

Removal of thiobencarb in aqueous solution by zero valent iron.

Chemosphere 2008 Jan 25;70(3):511-5. Epub 2007 Oct 25.

Department of Chemistry for Materials, Graduate School of Engineering, Mie University, Tsu, Mie 514-8507, Japan.

A cost-effective method with zero valent iron (ZVI) powder was developed for the purification of thiobencarb (TB)-contaminated water. The removal treatment was performed in the batch system. A sample solution of 10 ml containing 10 microg ml(-1) of TB could be almost completely treated by 100mg of ZVI at 25 degrees C for 12h of treatment time. Since the formation of chloride ion in the aqueous solution during the treatment of TB was observed, the removal of TB with ZVI may contain two processes: reduction (degradation) and adsorption. Because the present treatment for TB is simple, easy handling and cheap, the developed technology with ZVI can contribute to the treatment of agricultural wastewaters.
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http://dx.doi.org/10.1016/j.chemosphere.2007.09.017DOI Listing
January 2008

Clinical, histologic and immunologic features of pemphigus in Bangladesh.

Int J Dermatol 2006 Nov;45(11):1317-8

Department of Dermatology & Venereology, Combined Military Hospital Dhaka, Dhaka Cantonment, and Bangabandu Sheikh Mujib Medical University, Dhaka, Bangladesh.

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http://dx.doi.org/10.1111/j.1365-4632.2006.02942.xDOI Listing
November 2006
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