Displaying publications 481 - 500 of 624 in total

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  1. Lee XJ, Lee LY, Hiew BYZ, Gan S, Thangalazhy-Gopakumar S, Kiat Ng H
    Bioresour Technol, 2017 Dec;245(Pt A):944-953.
    PMID: 28946195 DOI: 10.1016/j.biortech.2017.08.175
    This research investigated the removal of lead (Pb(2+)) by a novel biochar derived from palm oil sludge (POS-char) by slow pyrolysis. Multistage optimizations with central composite design were carried out to firstly optimize pyrolysis parameters to produce the best POS-char for Pb(2+) removal and secondly to optimize adsorption conditions for the highest removal of Pb(2+). The optimum pyrolysis parameters were nitrogen flowrateof30mLmin(-1), heating rateof10°Cmin(-1), temperatureof500°C and timeof30min. The optimum Pb(2+) adsorption conditions were concentrationof200mgL(-1), timeof60min, dosageof0.3g and pH of 3.02. The various functional groups within POS-char played a vital role in Pb(2+) uptake. Regeneration was demonstrated to be feasible using hydrochloric acid. Adsorption equilibrium was best described by Freundlich model. At low concentration range, adsorption kinetic obeyed pseudo-first-order model, but at high concentration range, it followed pseudo-second-order model. Overall, the results highlighted that POS-char is an effective adsorbent for Pb(2+) removal.
    Matched MeSH terms: Nitrogen
  2. Abd Jalil SN, Wang DK, Yacou C, Motuzas J, Smart S, Diniz da Costa JC
    Materials (Basel), 2016 Nov 18;9(11).
    PMID: 28774057 DOI: 10.3390/ma9110938
    This work investigates the structural formation and analyses of titania membranes (TM) prepared using different vacuum exposure times for molecular weight (MW) cut-off performance and oil/water separation. Titania membranes were synthesized via a sol-gel method and coated on macroporous alumina tubes followed by exposure to a vacuum between 30 and 1200 s and then calcined at 400 °C. X-ray diffraction and nitrogen adsorption analyses showed that the crystallite size and particle size of titania increased as a function of vacuum time. All the TM membranes were mesoporous with an average pore diameter of ~3.6 nm with an anatase crystal morphology. Water, glucose, sucrose, and polyvinylpyrrolidone with 40 and 360 kDa (PVP-40 kDa and PVP-360 kDa) were used as feed solutions for MW cut-off and hexadecane solution for oil filtration investigation. The TM membranes were not able to separate glucose and sucrose, thus indicating the membrane pore sizes are larger than the kinetic diameter of sucrose of 0.9 nm, irrespective of vacuum exposure time. They also showed only moderate rejection (20%) of the smaller PVP-40 kDa, however, all the membranes were able to obtain an excellent rejection of near 100% for the larger PVP-360 kDa molecule. Furthermore, the TM membranes were tested for the separation of oil emulsions with a high concentration of oil (3000 ppm), reaching high oil rejections of more than 90% of oil. In general, the water fluxes increased with the vacuum exposure time indicating a pore structural tailoring effect. It is therefore proposed that a mechanism of pore size tailoring was formed by an interconnected network of Ti-O-Ti nanoparticles with inter-particle voids, which increased as TiO₂ nanoparticle size increased as a function of vacuum exposure time, and thus reduced the water transport resistance through the TM membranes.
    Matched MeSH terms: Nitrogen
  3. Norfazillah Ab Manan, Rozita Hod, Hanizah Mohd Yusoff, Mazrura Sahani, Rosnah Ismail, Wan Rozita Wan Mahiyuddin
    Int J Public Health Res, 2016;6(1):707-712.
    MyJurnal
    Air pollution has been widely known to have an influence on health of the general population.
    Air pollution can result from natural causes, human activities and transboundary air pollution.
    Weather and climate play crucial role in determining the pattern of air quality. In recent years,
    air pollution and recurrent episodes of haze has become a major concern in Malaysia.
    Surveillance data on concentrations of main air pollutants such as carbon dioxide, (CO2),
    Nitrogen Dioxide (NO2), Ozone (O3), sulphur dioxide (SO2) and particulate matter (PM10)
    were found to be higher during the haze days and this may have an impact on health of the
    community as reflected by an increase in hospital admissions particularly the respiratory and
    cardiovascular diseases.
    Matched MeSH terms: Nitrogen Dioxide
  4. Nagymihály M, Vásarhelyi BM, Barrière Q, Chong TM, Bálint B, Bihari P, et al.
    Stand Genomic Sci, 2017;12:75.
    PMID: 29255570 DOI: 10.1186/s40793-017-0298-3
    Strain CCMM B554, also known as FSM-MA, is a soil dwelling and nodule forming, nitrogen-fixing bacterium isolated from the nodules of the legume Medicago arborea L. in the Maamora Forest, Morocco. The strain forms effective nitrogen fixing nodules on species of the Medicago, Melilotus and Trigonella genera and is exceptional because it is a highly effective symbiotic partner of the two most widely used accessions, A17 and R108, of the model legume Medicago truncatula Gaertn. Based on 16S rRNA gene sequence, multilocus sequence and average nucleotide identity analyses, FSM-MA is identified as a new Ensifer meliloti strain. The genome is 6,70 Mbp and is comprised of the chromosome (3,64 Mbp) harboring 3574 predicted genes and two megaplasmids, pSymA (1,42 Mbp) and pSymB (1,64 Mbp) with respectively 1481 and 1595 predicted genes. The average GC content of the genome is 61.93%. The FSM-MA genome structure is highly similar and co-linear to other E. meliloti strains in the chromosome and the pSymB megaplasmid while, in contrast, it shows high variability in the pSymA plasmid. The large number of strain-specific sequences in pSymA as well as strain-specific genes on pSymB involved in the biosynthesis of the lipopolysaccharide and capsular polysaccharide surface polysaccharides may encode novel symbiotic functions explaining the high symbiotic performance of FSM-MA.
    Matched MeSH terms: Nitrogen
  5. Jamil DM, Al-Okbi AK, Al-Baghdadi SB, Al-Amiery AA, Kadhim A, Gaaz TS, et al.
    Chem Cent J, 2018 Feb 05;12(1):7.
    PMID: 29404816 DOI: 10.1186/s13065-018-0376-7
    BACKGROUND: Relatively inexpensive, stable Schiff bases, namely 3-((4-hydroxybenzylidene)amino)-2-methylquinazolin-4(3H)-one (BZ3) and 3-((4-(dimethylamino)benzylidene)amino)-2-methylquinazolin-4(3H)-one (BZ4), were employed as highly efficient inhibitors of mild steel corrosion by corrosive acid.

    FINDINGS: The inhibition efficiencies were estimated based on weight loss method. Moreover, scanning electron microscopy was used to investigate the inhibition mechanism. The synthesized Schiff bases were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and micro-elemental analysis. The inhibition efficiency depends on three factors: the amount of nitrogen in the inhibitor, the inhibitor concentration and the inhibitor molecular weight.

    CONCLUSIONS: Inhibition efficiencies of 96 and 92% were achieved with BZ4 and BZ3, respectively, at the maximum tested concentration. Density functional theory calculations of BZ3 and BZ4 were performed to compare the effects of hydroxyl and N,N-dimethylamino substituents on the inhibition efficiency, providing insight for designing new molecular structures that exhibit enhanced inhibition efficiencies.

    Matched MeSH terms: Nitrogen
  6. Lam MQ, Nik Mut NN, Thevarajoo S, Chen SJ, Selvaratnam C, Hussin H, et al.
    3 Biotech, 2018 Feb;8(2):104.
    PMID: 29404232 DOI: 10.1007/s13205-018-1133-2
    A halophilic bacterium, Virgibacillus sp. strain CD6, was isolated from salted fish and its extracellular protease was characterized. Protease production was found to be highest when yeast extract was used as nitrogen source for growth. The protease exhibited stability at wide range of salt concentration (0-12.5%, w/v), temperatures (20-60 °C), and pH (4-10) with maximum activity at 10.0% (w/v) NaCl, 60 °C, pH 7 and 10, indicating its polyextremophilicity. The protease activity was enhanced in the presence of Mg2+, Mn2+, Cd2+, and Al3+ (107-122% relative activity), and with retention of activity > 80% for all of other metal ions examined (K+, Ca2+, Cu2+, Co2+, Ni2+, Zn2+, and Fe3+). Both PMSF and EDTA inhibited protease activity, denoting serine protease and metalloprotease properties, respectively. High stability (> 70%) was demonstrated in the presence of organic solvents and detergent constituents, and the extracellular protease from strain CD6 was also found to be compatible in commercial detergents. Proteinaceous stain removal efficacy revealed that crude protease of strain CD6 could significantly enhance the performance of commercial detergent. The protease from Virgibacillus sp. strain CD6 could serve as a promising alternative for various applications, especially in detergent industry.
    Matched MeSH terms: Nitrogen
  7. Manogaran M, Shukor MY, Yasid NA, Khalil KA, Ahmad SA
    3 Biotech, 2018 Feb;8(2):108.
    PMID: 29430369 DOI: 10.1007/s13205-018-1123-4
    The herbicide glyphosate is often used to control weeds in agricultural lands. However, despite its ability to effectively kill weeds at low cost, health problems are still reported due to its toxicity level. The removal of glyphosate from the environment is usually done by microbiological process since chemical process of degradation is ineffective due to the presence of highly stable bonds. Therefore, finding glyphosate-degrading microorganisms in the soil of interest is crucial to remediate this glyphosate.Burkholderia vietnamiensisstrain AQ5-12 was found to have glyphosate-degrading ability. Optimisation of biodegradation condition was carried out utilising one factor at a time (OFAT) and response surface methodology (RSM). Five parameters including carbon and nitrogen source, pH, temperature and glyphosate concentration were optimised. Based on OFAT result, glyphosate degradation was observed to be optimum at fructose concentration of 6, 0.5 g/L ammonia sulphate, pH 6.5, temperature of 32 °C and glyphosate concentration at 100 ppm. Meanwhile, RSM resulted in a better degradation with 92.32% of 100 ppm glyphosate compared to OFAT. The bacterium was seen to tolerate up to 500 ppm glyphosate while increasing concentration results in reduced degradation and bacterial growth rate.
    Matched MeSH terms: Nitrogen
  8. Rupani PF, Embrandiri A, Ibrahim MH, Shahadat M, Hansen SB, Mansor NNA
    3 Biotech, 2017 Jul;7(3):155.
    PMID: 28623493 DOI: 10.1007/s13205-017-0770-1
    Several technologies are being applied for treatment of palm oil mill wastes. Among them, the biological treatments (vermicomposting) have widely been recognized as one of the most efficient and eco-friendly methods for converting organic waste materials into valuable products. The present study focuses on vermicomposting of acidic palm oil mill effluent (POME) mixed with the palm pressed fibre (PPF) which are found difficult to decompose in the environment. The industrial waste (POME) was vermicomposted using Lumbricus rubellus under laboratory conditions for a period of 45 days. A significant improvement in nitrogen, phosphorus, and potassium content was monitored during vermicomposting process. In addition, the decline in C:N ratio of vermicompost (up to 17.20 ± 0.60) reflects the degree of stabilization of POME-PPF mixture. Different percentages of the vermicompost extract obtained from POME-PPF mixture were also examined for the germination of mung bean (Vigna radiata) seed. The results showed that 75% vermicompost extract demonstrated better performance for the seed germination. On the basis of significant findings, POME-PPF mixture can be successfully used as a feeding material for the earthworms, while on the other hand, it can also be used as a cost-effective fertilizer for the germination and the proper growth of mung bean.
    Matched MeSH terms: Nitrogen
  9. Samsuddin NAC, Khan MF, Maulud KNA, Hamid AH, Munna FT, Rahim MAA, et al.
    Sci Total Environ, 2018 Jul 15;630:1502-1514.
    PMID: 29554768 DOI: 10.1016/j.scitotenv.2018.02.289
    Southeast Asian haze is a semi-natural phenomenon that chokes the region each year during the dry monsoon season. Smoke-haze episodes caused by the vegetation and peat fires in Indonesia severely affected large parts of Malaysia during the 2015 El Niño phenomenon. This study aimed to evaluate the factors that influenced the concentrations of aerosol and trace gases during the 2015 haze and non-haze period on a semi-urban site in the southern part of Malaysian peninsula that facing Sumatra (Muar, Site A), and on an urban site near to Kuala Lumpur, influenced by the city centre (Cheras, Site B). Local land use data and the cluster of air mass weighted backward trajectory were used to identify the potential factors from local sources and the transboundary region, respectively. The annual median concentrations of PM10 for semi-urban and urban sites were 45.0μg/m3 and 47.0μg/m3, respectively for the study period (Jan-Dec 2015) from the hourly observation dataset. The highest PM10 concentrations during the haze were 358μg/m3 and 415μg/m3 for the two sites, respectively, representing absolutely unhealthy air. However, the trace gases were within the safe threshold. The average concentrations of PM10 and carbon monoxide were two fold higher during the haze than the non-haze episodes on both sites. Nitrogen dioxide was more influenced by haze compared with sulphur dioxide and ozone. The results of the land use change suggest that the local factor can also partially affect the air pollution on the urban area (Site B) but more visible in 2015. The results of the backward trajectory and the wildfire radiative power showed that the smoke-haze episodes that affected Malaysia in 2015 were mainly initiated in the Indonesian Sumatra and Kalimantan regions. This study provides a very useful information towards the impacted region during El Niño haze episode.
    Matched MeSH terms: Nitrogen Dioxide
  10. Ismail IN, Taufik M, Umor NA, Norulhuda MR, Zulkarnaini Z, Ismail S
    Water Sci Technol, 2022 Dec;86(12):3093-3112.
    PMID: 36579872 DOI: 10.2166/wst.2022.403
    Treatment of ammonia- and nitrate-rich wastewater, such as that generated in the aquaculture industry, is important to prevent environmental pollution. The anaerobic ammonium oxidation (anammox) process has been reported as a great alternative in reducing ammoniacal nitrogen concentration in aquaculture wastewater treatment compared to conventional treatment systems. This paper will highlight the impact of the anammox process on aquaculture wastewater, particularly in the regulation of ammonia and nitrogen compounds. The state of the art for anammox treatment systems is discussed in comparison to other available treatment methods. While the anammox process is viable for the treatment of aquaculture wastewater, the efficiency of nitrogen removal could be further improved through the proper use of anammox bacteria, operating conditions, and microbial diversity. In conclusion, a new model of the anammox process is proposed in this review.
    Matched MeSH terms: Nitrogen
  11. Gephart JA, Henriksson PJG, Parker RWR, Shepon A, Gorospe KD, Bergman K, et al.
    Nature, 2021 Sep;597(7876):360-365.
    PMID: 34526707 DOI: 10.1038/s41586-021-03889-2
    Fish and other aquatic foods (blue foods) present an opportunity for more sustainable diets1,2. Yet comprehensive comparison has been limited due to sparse inclusion of blue foods in environmental impact studies3,4 relative to the vast diversity of production5. Here we provide standardized estimates of greenhouse gas, nitrogen, phosphorus, freshwater and land stressors for species groups covering nearly three quarters of global production. We find that across all blue foods, farmed bivalves and seaweeds generate the lowest stressors. Capture fisheries predominantly generate greenhouse gas emissions, with small pelagic fishes generating lower emissions than all fed aquaculture, but flatfish and crustaceans generating the highest. Among farmed finfish and crustaceans, silver and bighead carps have the lowest greenhouse gas, nitrogen and phosphorus emissions, but highest water use, while farmed salmon and trout use the least land and water. Finally, we model intervention scenarios and find improving feed conversion ratios reduces stressors across all fed groups, increasing fish yield reduces land and water use by up to half, and optimizing gears reduces capture fishery emissions by more than half for some groups. Collectively, our analysis identifies high-performing blue foods, highlights opportunities to improve environmental performance, advances data-poor environmental assessments, and informs sustainable diets.
    Matched MeSH terms: Nitrogen
  12. Elancheziyan M, Prakasham K, Eswaran M, Duraisamy M, Ganesan S, Lee SL, et al.
    Environ Res, 2023 Apr 15;223:115403.
    PMID: 36754108 DOI: 10.1016/j.envres.2023.115403
    The design and development of eco-friendly fabrication of cost-effective electrochemical nonenzymatic biosensors with enhanced sensitivity and selectivity are one of the emerging area in nanomaterial and analytical chemistry. In this aspect, we developed a facile fabrication of tertiary nanocomposite material based on cobalt and polymelamine/nitrogen-doped graphitic porous carbon nanohybrid composite (Co-PM-NDGPC/SPE) for the application as a nonenzymatic electrochemical sensor to quantify glucose in human blood samples. Co-PM-NDGPC/SPE nanocomposite electrode fabrication was achieved using a single-step electrodeposition method under cyclic voltammetry (CV) technique under 1 M NH4Cl solution at 20 constitutive CV cycles (sweep rate 20 mV/s). Notably, the fabricated nonenzymatic electroactive nanocomposite material exhibited excellent electrocatalytic sensing towards the quantification of glucose in 0.1 M NaOH over a wide concentration range from 0.03 to 1.071 mM with a sensitive limit of detection 7.8 μM. Moreover, the Co-PM-NDGPC nanocomposite electrode with low charge transfer resistance (Rct∼81 Ω) and high ionic diffusion indicates excellent stability, reproducibility, and high sensitivity. The fabricated nanocomposite materials exhibit a commendable sensing response toward glucose molecules present in the blood serum samples recommends its usage in real-time applications.
    Matched MeSH terms: Nitrogen
  13. Khairil M, Burslem DFRP
    Tree Physiol, 2018 11 01;38(11):1752-1760.
    PMID: 30137635 DOI: 10.1093/treephys/tpy082
    Aluminium (Al) accumulation is a common trait expressed in at least 60 plant families and particularly prevalent in tropical woody plants. However, the functional significance and genetic or physiological controls on Al accumulation are currently unknown. We tested the hypothesis that differential expression of Al accumulation among wild populations of the Al-accumulating tropical shrub Melastoma malabathricum L. is associated with habitat-related variation in total and exchangeable soil Al concentrations. Mature leaves and seeds were sampled from 20 populations of M. malabathricum growing in six habitats across Peninsular Malaysia, and soil was collected from each site. The seeds were grown in hydroponic solutions comprising 50% Hoagland's solution amended with Al in the form of 1.0 mM AlCl3 to test the hypothesis that differential expression of foliar Al accumulation is an inherited trait. Foliar Al concentrations varied significantly among populations, but were not consistently different among plants growing in different habitats and showed no relationship to total or exchangeable Al concentrations in soils collected at the 20 sites. Mean foliar Al concentration in wild plants was positively correlated with foliar calcium (Ca) concentrations, and with total soil nitrogen (N), Ca and magnesium (Mg) concentrations, across the 20 populations, and Al addition increased foliar concentrations of phosphorus, Ca, Mg and potassium in seedlings. The differential expression of Al accumulation in M. malabathricum populations is uncoupled to local variation in soil Al concentrations, but may be sensitive to local soil-related variation in the availability of other macro-nutrients, in particular N, Ca and Mg. Further research on the factors controlling Al uptake should focus on the plasticity of this trait within populations of Al accumulators and interactions with micro-habitat variation in the availability of the macronutrient cations.
    Matched MeSH terms: Nitrogen
  14. Abdelwahab SI, Hassan LE, Abdul Majid AM, Yagi SM, Mohan S, Elhassan Taha MM, et al.
    PMID: 22685485 DOI: 10.1155/2012/490136
    Emerging evidence suggests that reactive oxygen (ROS) and nitrogen (RNS) species can contribute to diverse signalling pathways of inflammatory and tumour cells. Cucurbitacins are a group of highly oxygenated triterpenes. Many plants used in folk medicine to treat cancer have been found to contain cucurbitacins displaying potentially important anti-inflammatory actions. The current study was designed to investigate the anti-ROS and -RNS effects of cucurbitacin L 2-O-β-glucoside (CLG) and the role of these signaling factors in the apoptogenic effects of CLG on human colon cancer cells (HT-29). This natural cucurbitacin was isolated purely from Citrullus lanatus var. citroides (Cucurbitaceae). The results revealed that CLG was cytotoxic to HT-29. CLG increased significantly (P < 0.05) RNA and protein levels of caspase-3 in HT-29 cells when verified using a colorimetric assay and realtime qPCR, respectively. The results showed that lipopolysaccharide/interferon-gamma (LPS/INF-γ) increased nitrous oxide (NO) production inR AW264.7macrophages, whereas N(G)-nitro-L-argininemethyl ester (L-NAME) and CLG curtailed it. This compound did not reveal any cytotoxicity on RAW264.7 macrophages and human normal liver cells (WRL-68) when tested using the MTT assay. Findings of ferric reducing antioxidant power (FRAP) and oxygen radical absorption capacity (ORAC) assays demonstrate the antioxidant properties of CLG. The apoptogenic property of CLG on HT-29 cells is thus related to inhibition of reactive nitrogen and oxygen reactive species and the triggering of caspase-3-regulated apoptosis.
    Matched MeSH terms: Nitrogen
  15. Jasmin MY, Isa NM, Kamarudin MS, Lim KC, Karim M
    Braz J Microbiol, 2024 Mar;55(1):529-536.
    PMID: 38280093 DOI: 10.1007/s42770-024-01246-9
    The accumulation of nitrogen compounds in shrimp farming water and effluent presents a major challenge. Ammonia is a form of nitrogen that limits shrimp growth due to its potential toxicity and effects on shrimp health and water quality. This study is aimed at identifying promising bioremediators from shrimp pond sludge to mitigate ammonia levels in both culture water and wastewater and at determining major bacterial communities in sludge using metagenomic analysis. A sludge sample was collected from a shrimp pond in Selangor, Malaysia, to isolate potential ammonia-removing bacteria. Out of 64 isolated strains, Bacillus flexus SS2 showed the highest growth in synthetic basal media (SBM) containing ammonium sulfate at a concentration of 70 mg/L as the sole nitrogen source. The strain was then incubated in SBM with varying pH levels and showed optimal growth at pH 6.5-7. After 24 h of incubation, B. flexus SS2 reduced the ammonia concentration from an initial concentration of 5 to 0.01 mg/L, indicating a 99.61% reduction rate, which was highest in SBM at pH 7. Moreover, the strain showed ammonia removal ability at concentrations ranging from 5 to 70 mg/L. Metagenomic analysis revealed that Proteobacteria was the most abundant phylum in the sludge, followed by Cyanobacteria, Actinobacteria, Chloraflexi, Firmicutes, and Campilobacterota. Bacillus flexus SS2 belongs to the Bacillota phylum and has the potential to serve as a bioremediator for removing ammonia from shrimp culture water and wastewater.
    Matched MeSH terms: Nitrogen
  16. Alidadi H, Khorsandi L, Shirani M
    Malays J Med Sci, 2018 Mar;25(2):72-81.
    PMID: 30918457 DOI: 10.21315/mjms2018.25.2.8
    Background: Recent studies have demonstrated that many nanoparticles have an adverse or toxic effect on the kidney.

    Objective: To investigate the nephroprotective effect of quercetin (QT) against renal injury induced by titanium dioxide nanoparticles (NTiO2) in rats.

    Methods: NTiO2-intoxicated rats received 50 mg/kg of NTiO2 for seven days. The QT + NTiO2 group was pretreated with QT for seven days before being administered NTiO2. Uric acid, creatinine, and blood urea nitrogen were considered to be biomarkers of nephrotoxicity. Catalase (CAT) and superoxide dismutase (SOD) activities and renal levels of malondialdehyde (MDA) were measured to assess the oxidative stress caused by NTiO2.

    Results: NTiO2 significantly increased the plasma level of the biomarkers. It also significantly decreased the activities of CAT (P = 0.008) and SOD (P = 0.004), and significantly increased the MDA levels (P = 0.007). NTiO2 caused proximal tubule damage, the accumulation of red blood cells, the infiltration of inflammatory cells, and reduced the glomerular diameters, as well as induced apoptosis in the proximal tubules. Pre-treatment with QT attenuated the histological changes, normalised the plasma biomarkers, suppressed oxidative stress, ameliorated the activities of CAT (P = 0.007) and SOD (P = 0.006), and reduced apoptosis (P < 0.001).

    Conclusion: QT was found to have a potent protective effect against nephrotoxicity induced by NTiO2 in rats. It also reduced apoptosis caused by NTiO2.

    Matched MeSH terms: Blood Urea Nitrogen
  17. Masseran N, Razali AM, Ibrahim K, Latif MT
    Environ Monit Assess, 2016 Jan;188(1):65.
    PMID: 26718946 DOI: 10.1007/s10661-015-5070-9
    The air pollution index (API) is an important figure used for measuring the quality of air in the environment. The API is determined based on the highest average value of individual indices for all the variables which include sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and suspended particulate matter (PM10) at a particular hour. API values that exceed the limit of 100 units indicate an unhealthy status for the exposed environment. This study investigates the risk of occurrences of API values greater than 100 units for eight urban areas in Peninsular Malaysia for the period of January 2004 to December 2014. An extreme value model, known as the generalized Pareto distribution (GPD), has been fitted to the API values found. Based on the fitted model, return period for describing the occurrences of API exceeding 100 in the different cities has been computed as the indicator of risk. The results obtained indicated that most of the urban areas considered have a very small risk of occurrence of the unhealthy events, except for Kuala Lumpur, Malacca, and Klang. However, among these three cities, it is found that Klang has the highest risk. Based on all the results obtained, the air quality standard in urban areas of Peninsular Malaysia falls within healthy limits to human beings.
    Matched MeSH terms: Nitrogen Dioxide/analysis
  18. Talib AT, Mokhtar MN, Baharuddin AS, Sulaiman A
    Bioresour Technol, 2014 Oct;169:428-38.
    PMID: 25079208 DOI: 10.1016/j.biortech.2014.07.033
    The effect of different aeration rates on the organic matter (OM) degradation during the active phase of oil palm empty fruit bunch (EFB)-rabbit manure co-composting process under constant forced-aeration system has been studied. Four different aeration rates, 0.13 L min(-1) kg(DM)(-1),0.26 L min(-1) kg(DM)(-1),0.49 L min(-1) kg(DM)(-1) and 0.74 L min(-1) kg(DM)(-1) were applied. 0.26 L min(-1) kg(DM)(-1) provided enough oxygen level (10%) for the rest of composting period, showing 40.5% of OM reduction that is better than other aeration rates. A dynamic mathematical model describing OM degradation, based on the ratio between OM content and initial OM content with correction functions of moisture content, free air space, oxygen and temperature has been proposed.
    Matched MeSH terms: Nitrogen/analysis
  19. Rahman MM, Azirun SM, Boyce AN
    PLoS One, 2013;8(5):e62941.
    PMID: 23667546 DOI: 10.1371/journal.pone.0062941
    Soil contamination by copper (Cu) and lead (Pb) is a widespread environmental problem. For phytoextraction to be successful and viable in environmental remediation, strategies that can improve plant uptake must be identified. In the present study we investigated the use of nitrogen (N) fertilizer as an efficient way to enhance accumulation of Cu and Pb from contaminated industrial soils into amaranth, Indian mustard and sunflower.
    Matched MeSH terms: Nitrogen/pharmacology
  20. Foo KY, Lee LK, Hameed BH
    Bioresour Technol, 2013 Apr;134:166-72.
    PMID: 23500574 DOI: 10.1016/j.biortech.2013.01.139
    This study evaluates the sugarcane bagasse derived activated carbon (SBAC) prepared by microwave heating for the adsorptive removal of ammonical nitrogen and orthophosphate from the semi-aerobic landfill leachate. The physical and chemical properties of SBAC were examined by pore structural analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and elemental analysis. The effects of adsorbent dosage, contact time and solution pH on the adsorption performance were investigated in a batch mode study at 30°C. Equilibrium data were favorably described by the Langmuir isotherm model, with a maximum monolayer adsorption capacity for ammonical nitrogen and orthophosphate of 138.46 and 12.81 mg/g, respectively, while the adsorption kinetic was best fitted to the pseudo-second-order kinetic model. The results illustrated the potential of sugarcane bagasse derived activated carbon for the adsorptive treatment of semi-aerobic landfill leachate.
    Matched MeSH terms: Nitrogen/isolation & purification
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