Displaying publications 21 - 40 of 70 in total

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  1. Mohammed Saifuddin, Amru N. Boyce
    Sains Malaysiana, 2017;46:1771-1778.
    As fossil energy resources are depleting quick and energy security is playing a vital role in the world economy. Quest for alternative energy sources have turned researches investigation in waste foods for next generation fuel. Biodiesel is usually considered to be environmentally friendly as it reduces greenhouse gas emission. Fish wastes rich in fatty acids and can be used as the raw material to produce biodiesel through transesterification reaction. The results showed that the seven peaks are fatty acid methyl esters, indicating all the triglycerides were successfully methylated to methyl esters. Fish based biodiesel provided a significant reduction in carbon monoxide (CO) and hydrocarbon (HC) emissions under engine loads of 15 (Nm) and required no engine modification. The viscosity of the produced biodiesel was within the range of international standards (ASTM). The biodiesel was found to contain a low base number and exhibited a lower specific fuel consumption compared to the conventional diesel. It can be concluded that biodiesel derived from waste fish oil can be considered as a potential source of commercial biodiesel.
    Matched MeSH terms: Carbon Monoxide
  2. Abdullah S, Abd Hamid FF, Ismail M, Ahmed AN, Wan Mansor WN
    Data Brief, 2019 Aug;25:103969.
    PMID: 31198825 DOI: 10.1016/j.dib.2019.103969
    The aim of the measurement of this data is to evaluate the Indoor Air Quality (IAQ) in terms of chemical and physical parameters. Data were collected at three different kindergartens having different surrounding activities (industrial, institutional, residential area). The chemical parameters measured were respirable suspended particulates of PM10, PM2.5, PM1, carbon monoxide and carbon dioxide, and the concentrations are within the acceptable limit. Physical parameters of wind speed are within the standard, while temperature and relative humidity exceeded the acceptable limit. A strong correlation was found between the chemical IAQ parameters with thermal comfort parameters (temperature and relative humidity). The concentration of IAQ pollutants is higher in order of residential > institutional > industrial.
    Matched MeSH terms: Carbon Monoxide
  3. Atarod P, Khlaife E, Aghbashlo M, Tabatabaei M, Hoang AT, Mobli H, et al.
    J Hazard Mater, 2021 04 05;407:124369.
    PMID: 33160782 DOI: 10.1016/j.jhazmat.2020.124369
    This study was set up to model and optimize the performance and emission characteristics of a diesel engine fueled with carbon nanoparticle-dosed water/‎diesel emulsion fuel using a combination of soft computing techniques. Adaptive neuro-fuzzy inference system tuned by particle ‎swarm algorithm was used for modeling the performance and emission parameters of the engine, while optimization of the engine operating parameters and the fuel composition was conducted via multiple-objective particle ‎swarm algorithm. The model input variables were: injection timing (35-41° CA BTDC), engine load (0-100%), nanoparticle dosage (0-150 μM), and water content (0-3 wt%). The model output variables included: brake specific fuel consumption, brake thermal efficiency, as well as carbon monoxide, carbon dioxide, nitrogen oxides, and unburned hydrocarbons emission concentrations. The training and testing of the modeling system were performed on the basis of 60 data patterns obtained from the experimental trials. The effects of input variables on the performance and emission characteristics of the engine were thoroughly analyzed and comprehensively discussed as well. According to the experimental results, injection timing and engine load could significantly affect all the investigated performance and emission parameters. Water and nanoparticle addition to diesel could markedly affect some performance and emission parameters. The modeling system could predict the output parameters with an R2 > 0.93, MSE carbon dioxide, carbon monoxide, nitrogen oxides, and unburned hydrocarbon emission concentrations ‎were found to be ‎7.26‎ vol%‎, ‎0.46 vol%‎, ‎95.7‎ ppm, and‎ 36.2 ppm, respectively, under the ‎selected optimal operating conditions while the quantity of brake thermal efficiency was found at an acceptable level (‎34.0‎%).‎ In general, the applied soft computing combination appears to be a promising approach to model and optimize operating parameters and fuel composition of diesel engines.
    Matched MeSH terms: Carbon Monoxide
  4. Nor Aishah Saidina Amin, Soon, Ee Peng
    MyJurnal
    Thermodynamic chemical equilibrium analysis using, total Gibbs energy minimization method, was carried out for methane oxidation to higher hydrocarbons. For a large methane conversion and a high selectivity to higher hydrocarbons, the system temperature and oxygen concentration played a vital role, whereas, the system pressure only slightly influenced the two variables. Numerical results showed that the conversion of methane increased with the concentration of oxygen and reaction temperature, but it decreased with pressure. Nevertheless, the presence of oxygen suppressed the formation of higher hydrocarbons which mostly consisted of aromatics, but enhanced the formation of hydrogen. As the system pressure increased, the aromatics, olefins and hydrogen yields diminished, but the paraffin yield improved. Carbon monoxide seemed to be the major oxygen-containing equilibrium product from methane oxidation, whilst almost no H2O, CH3OH and HCOH were detected although traces amount of carbon dioxide were formed at relatively lower temperature and higher pressure. The total Gibbs energy minimization method is useful to theoretically analyze the feasibility of methane conversion to higher hydrocarbons and syngas at the selected temperature and pressure.
    Matched MeSH terms: Carbon Monoxide
  5. Ng, C.G., Rusdi, A.R., Anne Yee, H.A.
    MyJurnal
    Objective: The aim of this study was to evaluate the validity and reliability of the Malay version of the Fagerstrom Test for Nicotine Dependence (FTND-M) based on a group of male staffs in the hospital. This study will also determine whether an abbreviated version of the FTND-M can be used as a screening tool for nicotine dependence. Method: 107 male staffs participated in the study. They were given the FTND-M and Malay version of Mini-International Neuropsychiatric Interview (M.I.N.I.)-L component. Their carbon monoxide level measured in their breath by using exhaled air. One week later, these participants were again given FTND-M. Results: The discriminatory ability of FTND-M was good with AUC 0.74 (P2 with the sensitivity of 70.1%, specificity of 70%, PPV of 79.7% and NPV of 58.3%. The FTND-M had moderate internal consistency with a Cronbach’s alpha of 0.67. The testretest reliability after 1 week was fair (Spearman’s rho=0.5, p)
    Matched MeSH terms: Carbon Monoxide
  6. Chan YH, Syed Abdul Rahman SNF, Lahuri HM, Khalid A
    Environ Pollut, 2021 Mar 01;278:116843.
    PMID: 33711630 DOI: 10.1016/j.envpol.2021.116843
    Carbon monoxide (CO) is a highly valuable component of syngas which could be used to synthesize various chemicals and fuels. Conventionally, syngas is derived from fossil-based natural gas and coal which are non-renewable. To curb the problem, CO2 gasification offers a win-win solution in which CO2 is converted with wastes to CO, achieving carbon emission mitigation and addressing waste disposal issue simultaneously. In this review, gasification of various wastes by CO2 with particular focus given to generation of CO-rich syngas is presented and critically discussed. This includes the effects of operating parameters (temperature, pressure and physicochemical properties of feedstocks) and advanced CO2 gasification techniques (catalytic CO2 gasification, CO2 co-gasification and microwave-driven CO2 gasification). Furthermore, associated technological challenges are highlighted and way forward in this field are proposed.
    Matched MeSH terms: Carbon Monoxide
  7. Suhel A, Norwazan AR, Rahman MRA, Ahmad KAB
    Data Brief, 2021 Apr;35:106838.
    PMID: 33659596 DOI: 10.1016/j.dib.2021.106838
    Present data article based on the investigation which enumerates the influence of CNG (compressed natural gas) and HCNG (hydrogen enriched compressed natural gas) on performance and emission parameters of direct injection diesel engine at 200, 220, and 240 bar injection pressures. The CNG and HCNG gaseous alternative fuels were injected in amount (by mass) of 10%, 20% and 30% as secondary fuels to enrich the pilot fuel (pure diesel) during the operation. The performance and emission data of dual fuel (CNG + pure diesel, HCNG + pure diesel) operation was analysed to compare with the pure diesel data. The data for present investigational work were assessed at 25%, 50%, 75% and 100% diverse engine loads for all trials under diverse injection pressures. Eddy current dynamometer was employed to raise the engine load from quartile to maximum. AVL DiGAS 444 N multi gas analyser was used to measure the values of carbon monoxide (CO), unburned hydrocarbon (UHC), and oxides of nitrogen (NOx) detrimental emissions in engine exhaust.
    Matched MeSH terms: Carbon Monoxide
  8. Rahman AU, Mohamed MHN, Jamshed S, Mahmood S, Iftikhar Baig MA
    J Pharm Bioallied Sci, 2020 Nov;12(Suppl 2):S671-S675.
    PMID: 33828359 DOI: 10.4103/jpbs.JPBS_245_19
    Background: The Fagerstrom test for nicotine dependence (FTND) is the most widely used scale for assessing nicotine dependence on conventional tobacco cigarettes (TCGs). But the FTND does not evaluate the subject's nicotine dependence to electronic cigarette (EC).

    Objective: The aim of this study was to develop and assess an equivalent modified FTND scale that measures the nicotine dependency via EC.

    Materials and Methods: The investigator developed the equivalent modified FTND scale that scores identical to the original scale, that is, 0-10. The developed scale piloted among 15 EC single users, that is, use only EC verified by carbon monoxide (CO) level of <8ppm. The assessment of the scale was done among 69 EC single users and observed for 1 year to determine their nicotine status.

    Results: The modified scale revealed an acceptable Cronbach α value of 0.725. Further test-retest reliability of the scale showed a satisfactory Spearman's rank correlation coefficient value of 0.730 (P > 0.05). A 1-year observation showed that of 69 single users, 11 single users completely stopped nicotine intake, 24 remained as EC single users, 15 shifted to dual-use, and 19 relapsed to TCG. Surprisingly, the EC users who completely stopped nicotine intake after 1 year had a low average nicotine dependence value of 3 that was measured by the modified FTND scale at the baseline.

    Conclusion: The modified FTND scale precisely identifies the physical dependence to nicotine via EC. Therefore, as per this study results the modified FTND scale can be applied in any EC-related studies to assess nicotine dependency via EC.

    Matched MeSH terms: Carbon Monoxide
  9. Nadzir MSM, Ashfold MJ, Khan MF, Robinson AD, Bolas C, Latif MT, et al.
    Environ Sci Pollut Res Int, 2018 Jan;25(3):2194-2210.
    PMID: 29116536 DOI: 10.1007/s11356-017-0521-1
    The Antarctic continent is known to be an unpopulated region due to its extreme weather and climate conditions. However, the air quality over this continent can be affected by long-lived anthropogenic pollutants from the mainland. The Argentinian region of Ushuaia is often the main source area of accumulated hazardous gases over the Antarctic Peninsula. The main objective of this study is to report the first in situ observations yet known of surface ozone (O3) over Ushuaia, the Drake Passage, and Coastal Antarctic Peninsula (CAP) on board the RV Australis during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC'16). Hourly O3 data was measured continuously for 23 days using an EcoTech O3 analyzer. To understand more about the distribution of surface O3 over the Antarctic, we present the spatial and temporal of surface O3 of long-term data (2009-2015) obtained online from the World Meteorology Organization of World Data Centre for greenhouse gases (WMO WDCGG). Furthermore, surface O3 satellite data from the free online NOAA-Atmospheric Infrared Sounder (AIRS) database and online data assimilation from the European Centre for Medium-Range Weather Forecasts (ECMWF)-Monitoring Atmospheric Composition and Climate (MACC) were used. The data from both online products are compared to document the data sets and to give an indication of its quality towards in situ data. Finally, we used past carbon monoxide (CO) data as a proxy of surface O3 formation over Ushuaia and the Antarctic region. Our key findings were that the surface O3 mixing ratio during MASEC'16 increased from a minimum of 5 ppb to ~ 10-13 ppb approaching the Drake Passage and the Coastal Antarctic Peninsula (CAP) region. The anthropogenic and biogenic O3 precursors from Ushuaia and the marine region influenced the mixing ratio of surface O3 over the Drake Passage and CAP region. The past data from WDCGG showed that the annual O3 cycle has a maximum during the winter of 30 to 35 ppb between June and August and a minimum during the summer (January to February) of 10 to 20 ppb. The surface O3 mixing ratio during the summer was controlled by photochemical processes in the presence of sunlight, leading to the depletion process. During the winter, the photochemical production of surface O3 was more dominant. The NOAA-AIRS and ECMWF-MACC analysis agreed well with the MASEC'16 data but twice were higher during the expedition period. Finally, the CO past data showed the surface O3 mixing ratio was influenced by the CO mixing ratio over both the Ushuaia and Antarctic regions. Peak surface O3 and CO hourly mixing ratios reached up to ~ 38 ppb (O3) and ~ 500 ppb (CO) over Ushuaia. High CO over Ushuaia led to the depletion process of surface O3 over the region. Monthly CO mixing ratio over Antarctic (South Pole) were low, leading to the production of surface O3 over the Antarctic region.
    Matched MeSH terms: Carbon Monoxide/analysis
  10. Adam IK, Heikal M, Aziz ARA, Yusup S
    Environ Sci Pollut Res Int, 2018 Oct;25(28):28500-28516.
    PMID: 30088249 DOI: 10.1007/s11356-018-2863-8
    The present work analyzes the effect of antioxidants on engine combustion performance of a multi-cylinder diesel engine fueled with PB30 and PB50 (30 and 50 vol.% palm biodiesel (PB)). Four antioxidants namely N,N'-diphenyl-1,4-phenylenediamine (DPPD), N-phenyl-1,4-phenylenediamine (NPPD), 2(3)-tert-Butyl-4-methoxyphenol (BHA), and 2-tert-butylbenzene-1,4-diol (TBHQ) were added at concentrations of 1000 and 2000 ppm to PB30 and PB50. TBHQ showed the highest activity in increasing oxidation stability in both PB30 and PB50 followed by BHA, DPPD, and NPPD respectively, without any negative effect on physical properties. Compared to diesel fuel, PB blends showed 4.61-6.45% lower brake power (BP), 5.90-8.69% higher brake specific fuel consumption (BSFC), 9.64-11.43% higher maximum in cylinder pressure, and 7.76-12.51% higher NO emissions. Carbon monoxide (CO), hydrocarbon (HC), and smoke opacity were reduced by 36.78-43.56%, 44.12-58.21%, and 42.59-63.94%, respectively, than diesel fuel. The start of combustion angles (SOC) of PB blends was - 13.2 to - 15.6 °CA BTDC, but the combustion delays were 5.4-7.8 °CA short compared to diesel fuel which were - 10 °CA BTDC and 11°CA respectively. Antioxidant fuels of PB showed higher BP (1.81-5.32%), CO (8.41-24.60%), and HC (13.51-37.35%) with lower BSFC (1.67-7.68%), NO (4.32-11.53%), maximum in cylinder pressure (2.33-4.91%) and peak heat release rates (HRR) (3.25-11.41%) than baseline fuel of PB. Similar SOC of - 13 to - 14 °CA BTDC was observed for PB blended fuels and antioxidants. It can be concluded that antioxidants' addition is effective in increasing the oxidation stability and in controlling the NOx emissions of palm biodiesel fuelled diesel engine.
    Matched MeSH terms: Carbon Monoxide/analysis
  11. Muhammad Aidil ZA, Hayati K, Rosliza AM
    Med J Malaysia, 2019 02;74(1):62-66.
    PMID: 30846665
    INTRODUCTION: For the last 30 years, tobacco smoking has continued to be the leading cause of premature deaths in Malaysia. Majority of the smokers in Malaysia are at the precontemplation and contemplation stages. Therefore, for the purpose of increasing smoking cessation among this group, the strategies that motivate them to quit smoking have to be reviewed.

    OBJECTIVE: This study aims to evaluate the effectiveness of carbon monoxide measurement feedback and the standard brief motivation adopted to encourage the smoker to quit.

    METHODS: A single-blind, cluster randomised controlled trial was conducted at ten tertiary colleges in Selangor. The study recruited young adult smokers at the precontemplation and contemplation stages. The subjects in the control group received a standard brief motivational strategy. On the other hand, the intervention group received additional carbon monoxide measurement and a motivational feedback module. A follow up was conducted at the first, third and sixth month to measure changes in smoking cessation stage. Subsequently, the secondary outcomes of a mean number of cigarette consumption and quit smoking attempt were analysed. A total of 160 subjects were required to detect the expected difference of 17% in primary outcomes between the groups. This study utilised Generalised Estimating Equations (GEE) to handle the clustering effects.

    CONCLUSION: Biomedical risk assessment feedback mechanism by using carbon monoxide is a promising aid to motivate the smoker to quit. This mechanism is a relatively easy, quick and non-invasive technique. Thus, it can be utilised as a reinforcement relating to the harmful effect of smoking. Besides, it can also increase the smokers' selfefficacy and decisional balance to adopt behavioural changes.

    Matched MeSH terms: Carbon Monoxide/analysis*
  12. Alwi A, Zulkifli NW, Sukiman NL, Yusoff A, Zakaria Z, Jamshaid M, et al.
    Environ Sci Pollut Res Int, 2019 Apr;26(12):11815-11826.
    PMID: 30811022 DOI: 10.1007/s11356-019-04603-6
    The availability of natural energy resources and the environmental issues are the most significant issues that are often highlighted by the world communities. With regard to these problems, isobutanol is a higher chain alcohol with four carbons which can be derived from biomass resources and it is potential to become an alternative fuel source besides the biodiesel for a diesel engine. The aim of this study is to evaluate the effect of isobutanol with Calophyllum inophyllum methyl ester and diesel as the ternary blend on physicochemical properties, engine performance, and emission characteristics. Five different fuel blends containing Calophyllum inophyllum biodiesel and isobutanol were tested on a single-cylinder direct injection diesel engine at different engine load of brake mean effective pressure. The physicochemical properties of the fuel blends were measured and then compared with neat diesel. The results indicate that the blend containing isobutanol and CIME gives a slight increase in BSEC and EGT and a minimal drop in BTE as compared to that of neat diesel. Besides that, the tested blends show a reduction of carbon monoxide and unburned hydrocarbon emissions. Meanwhile, all the fuel blends show a minimal increase in carbon dioxide and nitrogen oxides emissions, compared to that of neat diesel. Isobutanol can be proved as a preferred substitute for biodiesel and diesel fuels to achieve desired engine performance and emissions level.
    Matched MeSH terms: Carbon Monoxide/analysis
  13. Kanniah KD, Kamarul Zaman NAF, Kaskaoutis DG, Latif MT
    Sci Total Environ, 2020 Sep 20;736:139658.
    PMID: 32492613 DOI: 10.1016/j.scitotenv.2020.139658
    Since its first appearance in Wuhan, China at the end of 2019, the new coronavirus (COVID-19) has evolved a global pandemic within three months, with more than 4.3 million confirmed cases worldwide until mid-May 2020. As many countries around the world, Malaysia and other southeast Asian (SEA) countries have also enforced lockdown at different degrees to contain the spread of the disease, which has brought some positive effects on natural environment. Therefore, evaluating the reduction in anthropogenic emissions due to COVID-19 and the related governmental measures to restrict its expansion is crucial to assess its impacts on air pollution and economic growth. In this study, we used aerosol optical depth (AOD) observations from Himawari-8 satellite, along with tropospheric NO2 column density from Aura-OMI over SEA, and ground-based pollution measurements at several stations across Malaysia, in order to quantify the changes in aerosol and air pollutants associated with the general shutdown of anthropogenic and industrial activities due to COVID-19. The lockdown has led to a notable decrease in AOD over SEA and in the pollution outflow over the oceanic regions, while a significant decrease (27% - 30%) in tropospheric NO2 was observed over areas not affected by seasonal biomass burning. Especially in Malaysia, PM10, PM2.5, NO2, SO2, and CO concentrations have been decreased by 26-31%, 23-32%, 63-64%, 9-20%, and 25-31%, respectively, in the urban areas during the lockdown phase, compared to the same periods in 2018 and 2019. Notable reductions are also seen at industrial, suburban and rural sites across the country. Quantifying the reductions in major and health harmful air pollutants is crucial for health-related research and for air-quality and climate-change studies.
    Matched MeSH terms: Carbon Monoxide/analysis
  14. Afroz R, Hassan MN, Ibrahim NA
    Environ Res, 2003 Jun;92(2):71-7.
    PMID: 12854685
    In the early days of abundant resources and minimal development pressures, little attention was paid to growing environmental concerns in Malaysia. The haze episodes in Southeast Asia in 1983, 1984, 1991, 1994, and 1997 imposed threats to the environmental management of Malaysia and increased awareness of the environment. As a consequence, the government established Malaysian Air Quality Guidelines, the Air Pollution Index, and the Haze Action Plan to improve air quality. Air quality monitoring is part of the initial strategy in the pollution prevention program in Malaysia. Review of air pollution in Malaysia is based on the reports of the air quality monitoring in several large cities in Malaysia, which cover air pollutants such as Carbon monoxide (CO), Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3), and Suspended Particulate Matter (SPM). The results of the monitoring indicate that Suspended Particulate Matter (SPM) and Nitrogen Dioxide (NO2) are the predominant pollutants. Other pollutants such as CO, O(x), SO2, and Pb are also observed in several big cities in Malaysia. The air pollution comes mainly from land transportation, industrial emissions, and open burning sources. Among them, land transportation contributes the most to air pollution. This paper reviews the results of the ambient air quality monitoring and studies related to air pollution and health impacts.
    Matched MeSH terms: Carbon Monoxide/adverse effects
  15. Awang MB, Jaafar AB, Abdullah AM, Ismail MB, Hassan MN, Abdullah R, et al.
    Respirology, 2000 Jun;5(2):183-96.
    PMID: 10894109
    OBJECTIVE: Observations have been made on the long-term trends of major air pollutants in Malaysia including nitrogen dioxide, carbon monoxide, the ozone and total suspended particulate matter (particularly PM10), and sulfur dioxide, emitted from industrial and urban areas from early 1970s until late 1998.

    METHODOLOGY: The data show that the status of atmospheric environment in Malaysia, in particular in highly industrialized areas such as Klang Valley, was determined both by local and transboundary emissions and could be described as haze and non-haze periods.

    RESULTS: During the non-haze periods, vehicular emissions accounted for more than 70% of the total emissions in the urban areas and have demonstrated two peaks in the diurnal variations of the aforementioned air pollutants, except ozone. The morning 'rush-hour' peak was mainly due to vehicle emissions, while the late evening peak was mainly attributed to meteorological conditions, particularly atmospheric stability and wind speed. Total suspended particulate matter was the main pollutant with its concentrations at few sites often exceeding the Recommended Malaysia Air Quality Guidelines. The levels of other pollutants were generally within the guidelines. Since 1980, six major haze episodes were officially reported in Malaysia: April 1983, August 1990, June 1991, October 1991, August to October 1994, and July to October 1997. The 1997 haze episode was the worst ever experienced by the country. Short-term observations using continuous monitoring systems during the haze episodes during these periods clearly showed that suspended particulate matter (PM10) was the main cause of haze and was transboundary in nature. Large forest fires in parts of Sumatra and Kalimantan during the haze period, clearly evident in satellite images, were identified as the probable key sources of the widespread heavy haze that extended across Southeast Asia from Indonesia to Singapore, Malaysia and Brunei. The results of several studies have also provided strong evidence that biomass burning is the dominating source of particulate matter. The severity and extent of 1997's haze pollution was unprecedented, affecting some 300 million people across the region. The amount of economic costs suffered by Southeast Asian countries during this environmental disaster was enormous and is yet to be fully determined. Among the important sectors severely affected were air and land transport, shipping, construction, tourism and agro-based industries. The economic cost of the haze-related damage to Malaysia presented in this study include short-term health costs, production losses, tourism-related losses and the cost of avertive action. Although the cost reported here is likely to be underestimated, they are nevertheless significant (roughly RM1 billion).

    CONCLUSIONS: The general air quality of Malaysia since 1970 has deteriorated. Studies have shown that should no effective countermeasures be introduced, the emissions of sulfur dioxide, nitrogen oxides, particulate matter, hydrocarbons and carbon monoxide in the year 2005 would increase by 1.4, 2.12, 1.47 and 2.27 times, respectively, from the 1992 levels.

    Matched MeSH terms: Carbon Monoxide/analysis
  16. Welbourn EM, Wilson MT, Yusof A, Metodiev MV, Cooper CE
    Free Radic Biol Med, 2017 02;103:95-106.
    PMID: 28007575 DOI: 10.1016/j.freeradbiomed.2016.12.024
    Covalent hemoglobin binding to membranes leads to band 3 (AE1) clustering and the removal of erythrocytes from the circulation; it is also implicated in blood storage lesions. Damaged hemoglobin, with the heme being in a redox and oxygen-binding inactive hemichrome form, has been implicated as the binding species. However, previous studies used strong non-physiological oxidants. In vivo hemoglobin is constantly being oxidised to methemoglobin (ferric), with around 1% of hemoglobin being in this form at any one time. In this study we tested the ability of the natural oxidised form of hemoglobin (methemoglobin) in the presence or absence of the physiological oxidant hydrogen peroxide to initiate membrane binding. The higher the oxidation state of hemoglobin (from Fe(III) to Fe(V)) the more binding was observed, with approximately 50% of this binding requiring reactive sulphydryl groups. The hemoglobin bound was in a high molecular weight complex containing spectrin, ankyrin and band 4.2, which are common to one of the cytoskeletal nodes. Unusually, we showed that hemoglobin bound in this way was redox active and capable of ligand binding. It can initiate lipid peroxidation showing the potential to cause cell damage. In vivo oxidative stress studies using extreme endurance exercise challenges showed an increase in hemoglobin membrane binding, especially in older cells with lower levels of antioxidant enzymes. These are then targeted for destruction. We propose a model where mild oxidative stress initiates the binding of redox active hemoglobin to the membrane. The maximum lifetime of the erythrocyte is thus governed by the redox activity of the cell; from the moment of its release into the circulation the timer is set.
    Matched MeSH terms: Carbon Monoxide/metabolism
  17. Mohd Jaafar MN, Eldrainy YA, Mat Ali MF, Wan Omar WZ, Mohd Hizam MF
    Environ Sci Technol, 2012 Feb 21;46(4):2445-50.
    PMID: 22296110 DOI: 10.1021/es2025005
    The problems of global warming and the unstable price of petroleum oils have led to a race to develop environmentally friendly biofuels, such as palm oil or ethanol derived from corn and sugar cane. Biofuels are a potential replacement for fossil fuel, since they are renewable and environmentally friendly. This paper evaluates the combustion performance and emission characteristics of Refined, Bleached, and Deodorized Palm Oil (RBDPO)/diesel blends B5, B10, B15, B20, and B25 by volume, using an industrial oil burner with and without secondary air. Wall temperature profiles along the combustion chamber axis were measured using a series of thermocouples fitted axially on the combustion chamber wall, and emissions released were measured using a gas analyzer. The results show that RBDPO blend B25 produced the maximum emission reduction of 56.9% of CO, 74.7% of NOx, 68.5% of SO(2), and 77.5% of UHC compared to petroleum diesel, while air staging (secondary air) in most cases reduces the emissions further. However, increasing concentrations of RBDPO in the blends also reduced the energy released from the combustion. The maximum wall temperature reduction was 62.7% for B25 at the exit of the combustion chamber.
    Matched MeSH terms: Carbon Monoxide/analysis
  18. Vadrevu KP, Lasko K, Giglio L, Justice C
    Environ Pollut, 2014 Dec;195:245-56.
    PMID: 25087199 DOI: 10.1016/j.envpol.2014.06.017
    In this study, we assess the intense pollution episode of June 2013, in Riau province, Indonesia from land clearing. We relied on satellite retrievals of aerosols and Carbon monoxide (CO) due to lack of ground measurements. We used both the yearly and daily data for aerosol optical depth (AOD), fine mode fraction (FMF), aerosol absorption optical depth (AAOD) and UV aerosol index (UVAI) for characterizing variations. We found significant enhancement in aerosols and CO during the pollution episode. Compared to mean (2008-2012) June AOD of 0.40, FMF-0.39, AAOD-0.45, UVAI-1.77 and CO of 200 ppbv, June 2013 values reached 0.8, 0.573, 0.672, 1.77 and 978 ppbv respectively. Correlations of fire counts with AAOD and UVAI were stronger compared to AOD and FMF. Results from a trajectory model suggested transport of air masses from Indonesia towards Malaysia, Singapore and southern Thailand. Our results highlight satellite-based mapping and monitoring of pollution episodes in Southeast Asia.
    Matched MeSH terms: Carbon Monoxide/analysis
  19. Guan NC, Ann AY
    PMID: 23082572
    We studied the use of exhaled carbon monoxide (CO) to identify nicotine dependence among adult Malaysian male smokers. We conducted a cross-sectional study among 107 male smoking staff at a university hospital. We measured their exhaled CO using a piCO+ Smokerlyzer and diagnosed nicotine dependence using a Mini-International Neuropsychiatric Interview (MINI). The optimal cut-off value for exhaled CO was determined. The correlation between exhaled CO level and the Fagerstrom Test for Nicotine Dependence (FTND) was also assessed. The mean exhaled CO level among subjects with nicotine dependence (15.78 ppm) was significantly higher than subjects without nicotine dependence (9.62 ppm). The cut-off value used to identify smokers with nicotine dependence was set at 10 ppm (specificity = 0.721, sensitivity = 0.731, positive predictive value = 0.817 and negative predictive value = 0.617). Psychometric properties were stable with various durations of smoking. Exhaled CO correlated positively with FTND scores (Pearson's rho = 0.398, p = 0.01). Our findings show exhaled CO can be used to identify nicotine dependence among adult Malaysian male smokers.
    Matched MeSH terms: Carbon Monoxide*
  20. Edimansyah BA, Rusli BN, Naing L, Azwan BA, Aziah BD
    PMID: 19323052
    The purpose of this study was to determine the indoor air quality (IAQ) status of an automotive assembly plant in Rawang, Selangor, Malaysia using selected IAQ parameters, such as carbon dioxide (CO2), carbon monoxide (CO), temperature, relative humidity (RH) and respirable particulate matter (PM10). A cross-sectional study was conducted in the paint shop and body shop sections of the plant in March 2005. The Q-TRAK Plus IAQ Monitor was used to record the patterns of CO, CO2, RH and temperature; whilst PM10 was measured using DUSTTRAK Aerosol Monitor over an 8-hour time weight average (8-TWA). It was found that the average temperatures, RH and PM10 in the paint shop section and body shop sections exceeded the Department of Safety and Health (DOSH) standards. The average concentrations of RH and CO were slightly higher in the body shop section than in the paint shop section, while the average concentrations of temperature and CO2 were slightly higher in the paint shop section than in the body shop section. There was no difference in the average concentrations of PM10 between the two sections.
    Matched MeSH terms: Carbon Monoxide/analysis
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