Displaying publications 21 - 35 of 35 in total

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  1. Minhat FI, Yahya K, Talib A, Ahmad O
    Trop Life Sci Res, 2013 Aug;24(1):35-43.
    PMID: 24575240 MyJurnal
    The distribution of benthic Foraminifera throughout the coastal waters of Taman Negara Pulau Pinang (Penang National Park), Malaysia was studied to assess the impact of various anthropogenic activities, such as fishing, ecotourism and floating cage culture. Samples were obtained at 200 m intervals within the subtidal zone, extending up to 1200 m offshore at Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh. The depth within coastal waters ranged between 1.5 m and 10.0 m, with predominantly muddy substrate at most stations. Water quality analysis showed little variation in micronutrient (nitrite, NO2; nitrate, NO3; ammonia, NH4 and orthophosphate, PO4) concentrations between sampling stations. Temperature (29.6±0.48°C), salinity (29.4±0.28 ppt), dissolved oxygen content (5.4±0.95 mg/l) and pH (8.5± 0.13) also showed little fluctuation between stations. A total of nine genera of foraminifera were identified in the study (i.e., Ammonia, Elphidium, Ammobaculites, Bigenerina, Quinqueloculina, Reopax, Globigerina, Textularia and Nonion). The distribution of benthic foraminifera was dominated by opportunistic groups that have a high tolerance to anthropogenic stressors. Ammonia had the highest frequency of occurrence (84.7%), followed by Bigenerina (50%), Ammobaculites (44.2%) and Elphidium (38.9%). The Ammonia-Elphidium Index (AEI) was used to describe the hypoxic condition of benthic communities at all sites. Teluk Bahang had the highest AEI value. The foraminiferal assemblages and distribution in Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh showed no correlation with physical or chemical environmental parameters.
    Matched MeSH terms: Nitrogen Oxides
  2. Fatema K, Wan Maznah WO, Isa MM
    Trop Life Sci Res, 2014 Dec;25(2):1-19.
    PMID: 27073596 MyJurnal
    In this study, factor analysis (FA) was applied to extract the hidden factors responsible for water quality variations during both wet and dry seasons. Water samples were collected from six sampling stations (St. 1 Lalang River, St. 2 Semeling River, St. 3 Jagung River, St. 4 Teluk Wang River, St. 5 Gelam River and St. 6 Derhaka River) in the Merbok estuary, Malaysia from January to December 2011; the samples were further analysed in the laboratory. Correlation analysis of the data sets showed strong correlations between the parameters. Nutrients such as nitrate (NO3 (-)), nitrite (NO2 (-)), ammonia (NH3) and phosphate (PO4 (3-)) were determined to be critical indicators of water quality throughout the year. Influential water quality parameters during the wet season were conductivity, salinity, biochemical oxygen demand (BOD), dissolved oxygen (DO) and chlorophyll a (Chla), whereas total suspended solid (TSS) and pH were critical water quality indicators during the dry season. The Kruskal-Wallis H test showed that water quality parameters were significantly different among the sampling months and stations (p<0.05), and Mann-Whitney U tests further revealed that the significantly different parameters were temperature, pH, DO, TSS, NO2 (-) and BOD (p<0.01), whereas salinity, conductivity, NO3 (-), PO4 (3-), NH3 and Chla were not significantly different (p>0.05). Water quality parameters in the estuary varied on both temporal and spatial scales and these results may serve as baseline information for estuary management, specifically for the Merbok estuary.
    Matched MeSH terms: Nitrogen Oxides
  3. Asma Liyana Shaari, Misni Surif, Faazaz Abd. Latiff, Wan Maznah Wan Omar, Mohd Noor Ahmad
    Trop Life Sci Res, 2011;22(1):-.
    MyJurnal
    Many reports have revealed that the abundance of microalgae in shrimp ponds vary with changes in environmental factors such as light, temperature, pH, salinity and nutrient level throughout a shrimp culture period. In this study, shrimp cultivation period was divided into three stages (initial = week 0–5, mid = week 6–10 and final = week 11–15). Physical and chemical parameters throughout the cultivation period were studied and species composition of microalgae was monitored. Physical parameters were found to
    fluctuate widely with light intensity ranging between 182.23–1278 µmol photon m–2s–1, temperature between 29.56ºC –31.59ºC, dissolved oxygen (DO) between 4.56–8.21 mg/l, pH between 7.65–8.49 and salinity between 20‰–30‰. Ammonium (NH4+-N), nitrite (NO2– -N), nitrate (NO3– -N), and orthophosphate (PO43– -P) concentrations in the pond at all cultivation stages ranged from 0.017 to 0.38 mg/l, 0.24 to 2.12 mg/l, 0.06 to 0.98 mg/l and 0.16 to 1.93 mg/l respectively. Statistical test (ANOVA) showed that there were no significant difference (p
    Matched MeSH terms: Nitrogen Oxides
  4. Hutagalung, Sabar D., Woon, Wu S., Khatijah A. Yaacob, Lockman, Zainovia
    MyJurnal
    P-type transparent conductive oxide of copper aluminum oxide (CuAlO2) thin films were prepared by using sol-gel method with nitrate solutions as starting precursor. Copper nitrate and aluminum nitrate were selected as raw materials that provide the copper and aluminum source. The CuAlO2 thin films were deposited on pre-cleaned silicon substrate by spin-coating technique. To study of phase formation of CuAlO2, as prepared sample was dried and subjected to heat treatment at various temperatures. The heat-treated samples were characterized by x-ray diffraction (XRD) and energy dispersive x-ray (EDX). From XRD analysis result found that CuAlO2 phase was formed after annealing at 1100 o C for 4 hrs. EDX result of annealed sample at 1100 o C shows composition of Cu and Al that indicate the possibility of forming CuAlO2.
    Matched MeSH terms: Nitrogen Oxides
  5. Cui J, Zhang Y, Yang F, Chang Y, Du K, Chan A, et al.
    Ecotoxicol Environ Saf, 2020 Apr 15;193:110344.
    PMID: 32092583 DOI: 10.1016/j.ecoenv.2020.110344
    To identify seasonal fluxes and sources of dissolved inorganic nitrogen (DIN) wet deposition, concentrations and δ15N signatures of nitrate (NO3-) and ammonium (NH4+) in wet precipitation were measured at four typical land-use types in the Three Gorges reservoir (TGR) area of southwest China for a one-year period. Higher DIN fluxes were recorded in spring and summer and their total fluxes (averaged 7.58 kg N ha-1) were similar to the critical loads in aquatic ecosystems. Significant differences of precipitation δ15N were observed for NH4+-N between town and wetland sites in spring and between urban and rural sites in summer. For NO3--N, significant differences of precipitation δ15N were observed between town and rural sites in spring and between urban and town sites in autumn, respectively. Quantitative results of NO3--N sources showed that both biomass burning and coal combustion had higher fluxes at the urban site especially in winter (0.18 ± 0.09 and 0.19 ± 0.08 kg N ha-1), which were about three times higher than those at the town site. A similar finding was observed for soil emission and vehicle exhausts in winter. On the whole, DIN wet deposition averaged at 12.13 kg N ha-1 yr-1 with the urban site as the hotspot (17.50 kg N ha-1 yr-1) and regional NO3--N fluxes had a seasonal pattern with minimum values in winter. The contribution to NO3--N wet deposition from biomass burning was 26.1 ± 14.1%, which is the second dominant factor lower than coal combustion (26.5 ± 12.6%) in the TGR area during spring and summer. Hence N emission reduction from biomass burning, coal combustion and vehicle exhausts should be strengthened especially in spring and summer to effectively manage DIN pollution for the sustainable development in TGR area.
    Matched MeSH terms: Nitrogen Oxides
  6. Suhaimi Suratman, Azyyati Abdul Aziz, Norhayati Mohd Tahir, Lee HL
    Sains Malaysiana, 2018;47:651-659.
    A study was carried out to determine the distribution and behaviour of nitrogen (N) compounds (nitrite, nitrate, ammonia,
    dissolved and particulate organic nitrogen) in Sungai Terengganu estuary (TRE). Surface water samples were collected
    during ebb neap and spring tides for the longitudinal survey along the salinity gradient. The results indicated that all N
    compounds behave non-conservatively with addition during both tidal cycles, except for nitrate which exhibited removal
    behaviour during spring tide. In general, higher concentration of N compounds was observed during spring tide compared
    to neap tide. It is suggested that during spring tide, stronger water turbulence resulted in resuspension of nutrients in
    bottom sediment and lead to the increase in N compounds concentrations in the surface water. The diurnal survey for the
    freshwater station showed that the concentrations of N compounds follow the ebb and flood variations, whereas for the
    coastal station the reverse trend was observed. Comparisons with a previous study under similar tidal conditions show
    there was an increase in nitrite and ammonia concentrations in TRE, which was probably due to increase in discharge
    from the rapid development activities around this area. In addition, the presence of a breakwater at the lower part of
    the estuary may also contribute to the high nutrient content in the estuary due to restricted outflow of nutrients to the
    coastal area. Overall, the results from this study highlighted the importance of monitoring the N compounds for future
    protection of the estuary.
    Matched MeSH terms: Nitrogen Oxides
  7. Soyiri IN, Reidpath DD, Sarran C
    Int J Biometeorol, 2013 Jul;57(4):569-78.
    PMID: 22886344 DOI: 10.1007/s00484-012-0584-0
    Asthma is a chronic condition of great public health concern globally. The associated morbidity, mortality and healthcare utilisation place an enormous burden on healthcare infrastructure and services. This study demonstrates a multistage quantile regression approach to predicting excess demand for health care services in the form of asthma daily admissions in London, using retrospective data from the Hospital Episode Statistics, weather and air quality. Trivariate quantile regression models (QRM) of asthma daily admissions were fitted to a 14-day range of lags of environmental factors, accounting for seasonality in a hold-in sample of the data. Representative lags were pooled to form multivariate predictive models, selected through a systematic backward stepwise reduction approach. Models were cross-validated using a hold-out sample of the data, and their respective root mean square error measures, sensitivity, specificity and predictive values compared. Two of the predictive models were able to detect extreme number of daily asthma admissions at sensitivity levels of 76 % and 62 %, as well as specificities of 66 % and 76 %. Their positive predictive values were slightly higher for the hold-out sample (29 % and 28 %) than for the hold-in model development sample (16 % and 18 %). QRMs can be used in multistage to select suitable variables to forecast extreme asthma events. The associations between asthma and environmental factors, including temperature, ozone and carbon monoxide can be exploited in predicting future events using QRMs.
    Matched MeSH terms: Nitrogen Oxides/analysis
  8. Gharibrezal M, Ashraf MA
    J Environ Biol, 2016 09;37(5 Spec No):1097-1104.
    PMID: 29989741
    Bera Lake is the largest natural fresh water reservoir in Malaysia. It has vital environmental and ecological importance for human and wild life. Nevertheless, water quality of this lake has been degraded during the last few decades due to land development projects at catchment area. Therefore, a comprehensive water quality assessment of Bera Lake was implemented in order to compare current water quality with the implementation of land development projects. In situ water quality surveying was implemented using calibrated full option Hydrolab DS 5. Eleven parameters viz., temperature, depth of sampling, salinity, Turbidity, total dried solid, pH, NH4(+), N03(-), Cl(-), saturation percentage of dissolved oxygen, specific conductivity were recorded in fifty one stations at 0.2h, 0.5h, and 0.8h depth. National Water Quality Standards for Malaysia (NWQS) and Water Quality were used to evaluate Bera Lake quality based on previous and resultant data. Vertical water quality analysis revealed a clear stratification in Bera Lake water profile in terms of temperature, dissolved oxygen, chloride (Cl(-)), nitrate (NO(3)), pH and specific conductivity (EC) parameters. Results clearly demonstrate the important role of land use changes since 1972 in the physico-chemical condition of water quality at Bera Lake. Classifications of water quality before and after land development project were calculated as class II and class V, respectively. A long-term and comprehensive monitoring of water quality assessment is recommended in order to reach plan of sustainable water resources use with conservation approach.
    Matched MeSH terms: Nitrogen Oxides/chemistry
  9. Pyle JA, Warwick NJ, Harris NR, Abas MR, Archibald AT, Ashfold MJ, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3210-24.
    PMID: 22006963 DOI: 10.1098/rstb.2011.0060
    We present results from the OP3 campaign in Sabah during 2008 that allow us to study the impact of local emission changes over Borneo on atmospheric composition at the regional and wider scale. OP3 constituent data provide an important constraint on model performance. Treatment of boundary layer processes is highlighted as an important area of model uncertainty. Model studies of land-use change confirm earlier work, indicating that further changes to intensive oil palm agriculture in South East Asia, and the tropics in general, could have important impacts on air quality, with the biggest factor being the concomitant changes in NO(x) emissions. With the model scenarios used here, local increases in ozone of around 50 per cent could occur. We also report measurements of short-lived brominated compounds around Sabah suggesting that oceanic (and, especially, coastal) emission sources dominate locally. The concentration of bromine in short-lived halocarbons measured at the surface during OP3 amounted to about 7 ppt, setting an upper limit on the amount of these species that can reach the lower stratosphere.
    Matched MeSH terms: Nitrogen Oxides/chemistry
  10. Fowler D, Nemitz E, Misztal P, Di Marco C, Skiba U, Ryder J, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3196-209.
    PMID: 22006962 DOI: 10.1098/rstb.2011.0055
    This paper reports measurements of land-atmosphere fluxes of sensible and latent heat, momentum, CO(2), volatile organic compounds (VOCs), NO, NO(2), N(2)O and O(3) over a 30 m high rainforest canopy and a 12 m high oil palm plantation in the same region of Sabah in Borneo between April and July 2008. The daytime maximum CO(2) flux to the two canopies differs by approximately a factor of 2, 1200 mg C m(-2) h(-1) for the oil palm and 700 mg C m(-2) h(-1) for the rainforest, with the oil palm plantation showing a substantially greater quantum efficiency. Total VOC emissions are also larger over the oil palm than over the rainforest by a factor of 3. Emissions of isoprene from the oil palm canopy represented 80 per cent of the VOC emissions and exceeded those over the rainforest in similar light and temperature conditions by on average a factor of 5. Substantial emissions of estragole (1-allyl-4-methoxybenzene) from the oil palm plantation were detected and no trace of this VOC was detected in or above the rainforest. Deposition velocities for O(3) to the rainforest were a factor of 2 larger than over oil palm. Emissions of nitrous oxide were larger from the soils of the oil palm plantation than from the soils of the rainforest by approximately 25 per cent. It is clear from the measurements that the large change in the species composition generated by replacing rainforest with oil palm leads to profound changes in the net exchange of most of the trace gases measured, and thus on the chemical composition of the boundary layer over these surfaces.
    Matched MeSH terms: Nitrogen Oxides/chemistry
  11. MacKenzie AR, Langford B, Pugh TA, Robinson N, Misztal PK, Heard DE, et al.
    Philos Trans R Soc Lond B Biol Sci, 2011 Nov 27;366(1582):3177-95.
    PMID: 22006961 DOI: 10.1098/rstb.2011.0053
    We report measurements of atmospheric composition over a tropical rainforest and over a nearby oil palm plantation in Sabah, Borneo. The primary vegetation in each of the two landscapes emits very different amounts and kinds of volatile organic compounds (VOCs), resulting in distinctive VOC fingerprints in the atmospheric boundary layer for both landscapes. VOCs over the Borneo rainforest are dominated by isoprene and its oxidation products, with a significant additional contribution from monoterpenes. Rather than consuming the main atmospheric oxidant, OH, these high concentrations of VOCs appear to maintain OH, as has been observed previously over Amazonia. The boundary-layer characteristics and mixing ratios of VOCs observed over the Borneo rainforest are different to those measured previously over Amazonia. Compared with the Bornean rainforest, air over the oil palm plantation contains much more isoprene, monoterpenes are relatively less important, and the flower scent, estragole, is prominent. Concentrations of nitrogen oxides are greater above the agro-industrial oil palm landscape than over the rainforest, and this leads to changes in some secondary pollutant mixing ratios (but not, currently, differences in ozone). Secondary organic aerosol over both landscapes shows a significant contribution from isoprene. Primary biological aerosol dominates the super-micrometre aerosol over the rainforest and is likely to be sensitive to land-use change, since the fungal source of the bioaerosol is closely linked to above-ground biodiversity.
    Matched MeSH terms: Nitrogen Oxides/chemistry
  12. Yam ML, Abdul Hafid SR, Cheng HM, Nesaretnam K
    Lipids, 2009 Sep;44(9):787-97.
    PMID: 19655189 DOI: 10.1007/s11745-009-3326-2
    Tocotrienols are powerful chain breaking antioxidant. Moreover, they are now known to exhibit various non-antioxidant properties such as anti-cancer, neuroprotective and hypocholesterolemic functions. This study was undertaken to investigate the anti-inflammatory effects of tocotrienol-rich fraction (TRF) and individual tocotrienol isoforms namely delta-, gamma-, and alpha-tocotrienol on lipopolysaccharide-stimulated RAW264.7 macrophages. The widely studied vitamin E form, alpha-tocopherol, was used as comparison. Stimulation of RAW264.7 with lipopolysaccharide induced the release of various inflammatory markers. 10 mcirog/ml of TRF and all tocotrienol isoforms significantly inhibited the production of interleukin-6 and nitric oxide. However, only alpha-tocotrienol demonstrated a significant effect in lowering tumor necrosis factor-alpha production. Besides, TRF and all tocotrienol isoforms except gamma-tocotrienol reduced prostaglandin E(2) release. It was accompanied by the down-regulation of cyclooxygenase-2 gene expression by all vitamin E forms except alpha-tocopherol. Collectively, the data suggested that tocotrienols are better anti-inflammatory agents than alpha-tocopherol and the most effective form is delta-tocotrienol.
    Matched MeSH terms: Nitrogen Oxides/immunology
  13. Pedersen M, Stafoggia M, Weinmayr G, Andersen ZJ, Galassi C, Sommar J, et al.
    Eur Urol Focus, 2018 01;4(1):113-120.
    PMID: 28753823 DOI: 10.1016/j.euf.2016.11.008
    BACKGROUND: Ambient air pollution contains low concentrations of carcinogens implicated in the etiology of urinary bladder cancer (BC). Little is known about whether exposure to air pollution influences BC in the general population.

    OBJECTIVE: To evaluate the association between long-term exposure to ambient air pollution and BC incidence.

    DESIGN, SETTING, AND PARTICIPANTS: We obtained data from 15 population-based cohorts enrolled between 1985 and 2005 in eight European countries (N=303431; mean follow-up 14.1 yr). We estimated exposure to nitrogen oxides (NO2 and NOx), particulate matter (PM) with diameter <10μm (PM10), <2.5μm (PM2.5), between 2.5 and 10μm (PM2.5-10), PM2.5absorbance (soot), elemental constituents of PM, organic carbon, and traffic density at baseline home addresses using standardized land-use regression models from the European Study of Cohorts for Air Pollution Effects project.

    OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used Cox proportional-hazards models with adjustment for potential confounders for cohort-specific analyses and meta-analyses to estimate summary hazard ratios (HRs) for BC incidence.

    RESULTS AND LIMITATIONS: During follow-up, 943 incident BC cases were diagnosed. In the meta-analysis, none of the exposures were associated with BC risk. The summary HRs associated with a 10-μg/m3 increase in NO2 and 5-μg/m3 increase in PM2.5 were 0.98 (95% confidence interval [CI] 0.89-1.08) and 0.86 (95% CI 0.63-1.18), respectively. Limitations include the lack of information about lifetime exposure.

    CONCLUSIONS: There was no evidence of an association between exposure to outdoor air pollution levels at place of residence and risk of BC.

    PATIENT SUMMARY: We assessed the link between outdoor air pollution at place of residence and bladder cancer using the largest study population to date and extensive assessment of exposure and comprehensive data on personal risk factors such as smoking. We found no association between the levels of outdoor air pollution at place of residence and bladder cancer risk.

    Matched MeSH terms: Nitrogen Oxides/adverse effects
  14. Zailina Hashim, Juliana Jalaludin, Norzila Muhamad Zainudin, Azizi Omar, Jamal H. Hashim
    MyJurnal
    A study on 30 asthmatic children was conducted in Kuala Lumpur. The objective of this study was to study the relationship between respirable particulate (PM10), sulphur dioxide, ozone and various meteorological factors such as humidity, level ofrainfall and temperature with asthma attacks. This study was conducted from 1st September to 31 December 1994. Patients were selected from the Paediatric Unit, Kuala Lumpur Hospital. Questionnaires were used to obtain information from their parents on the history and severity ofasthmatic attacks ofthese patients. Questionnaires were also used to determine if the indoor sources contributed to the attack. Diary cards were used to collect information on the frequency of asthmatic attacks. Each patient's progress was followed through every week during the study period and the attacks were recorded. The data on air quality on the PM10, sulphur dioxide, nitrogen dioxide, carbon monoxide and ozone were collected hourly using the microcomputer system of air monitoring unit from the Universiti Pertanian Malaysia air quality monitoring station located at the City Hall, Kuala Lumpur. The meteorological parameters such as temperature, relative humidity and rain-fall levels were also monitored daily. The asthmatic attack percentage was obtained by dividing the number of attacks in a day with the total number of sample and multiplying by a hundred. Statistical tests indicated that there was a significant correlation between asthmatic attacks and the PM10 concentrations (r=0.73), nitrogen dioxide (r=0.57) and.carbon monoxide (r=0.53) throughout the study period. During the haze episode, more significant correlations between asthmatic attacks, PM10 concentra-tions (0.86), carbon monoxide (0.79) and nitrogen oxide (0.53) were found. Multiple regression statistical test showed that PM10 had the greatest influence on the asthmatic attack rate. The minute respirable particulate which entered the respiratory system of the asthmatics triggered attacks on these patients.
    Matched MeSH terms: Nitrogen Oxides
  15. Shahadin MS, Ab Mutalib NS, Latif MT, Greene CM, Hassan T
    Lung Cancer, 2018 04;118:69-75.
    PMID: 29572006 DOI: 10.1016/j.lungcan.2018.01.016
    Hazardous air pollutants or chemical release into the environment by a variety of natural and/or anthropogenic activities may give adverse effects to human health. Air pollutants such as sulphur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), heavy metals and particulate matter (PM) affect number of different human organs, especially the respiratory system. The International Agency for Research on Cancer (IARC) reported that ambient air pollution is a cause of lung cancer. Recently, the agency has classified outdoor air pollution as well as PM air pollution as Group 1 carcinogens. In addition, several epidemiological studies have shown a positive association between air pollutants to lung cancer risks and mortality. However, there are only a few studies examining the molecular effects of air pollution exposure specifically in lung cancer due to multiple challenges to mimic air pollution exposure in basic experimentation. Another major issue is the lack of adequate adjustments for exposure misclassification as air pollution may differ temporo-spatially and socioeconomically. Thus, the purpose of this paper is to review the current molecular understanding of air pollution-related lung cancer and potential future direction in this challenging yet important research field.
    Matched MeSH terms: Nitrogen Oxides
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