Displaying publications 101 - 120 of 137 in total

Abstract:
Sort:
  1. Ujang Z, Soedjono E, Salim MR, Shutes RB
    Water Sci Technol, 2005;52(12):243-50.
    PMID: 16477992
    Municipal leachate was treated in an experimental unit of constructed wetlands of subsurface flow type. The parameters studied were organics (BOD and COD), solids and heavy metals (Zn, Ni, Cu, Cr and Pb). Using two types of emergent plants of Scirpus globulosus and Eriocaulon sexangulare, more than 80% removal was achieved for all the parameters. E. sexangulare removed organics and heavy metals better than Scirpus globulosus. A higher concentration of heavy metals in the influent did not change the removal efficiency.
    Matched MeSH terms: Organic Chemicals/isolation & purification; Organic Chemicals/metabolism
  2. Salleh AB, Basri M, Taib M, Jasmani H, Rahman RN, Rahman MB, et al.
    Appl Biochem Biotechnol, 2002 10 25;102-103(1-6):349-57.
    PMID: 12396136
    Recent studies on biocatalysis in water-organic solvent biphasic systems have shown that many enzymes retain their catalytic activities in the presence of high concentrations of organic solvents. However, not all enzymes are organic solvent tolerant, and most have limited and selective tolerance to particular organic solvents. Protein modification or protein tailoring is an approach to alter the characteristics of enzymes, including solubility in organic solvents. Particular amino acids may play pivotal roles in the catalytic ability of the protein. Attaching soluble modifiers to the protein molecule may alter its conformation and the overall polarity of the molecule. Enzymes, in particular lipases, have been chemically modified by attachment of aldehydes, polyethylene glycols, and imidoesters. These modifications alter the hydrophobicity and conformation of the enzymes, resulting in changes in the microenvironment of the enzymes. By these modifications, newly acquired properties such as enhancement of activity and stability and changes in specificity and solubility in organic solvents are obtained. Modified lipases were found to be more active and stable in organic solvents. The optimum water activity (a(w)) for reaction was also shifted by using modified enzymes. Changes in enantioselective behavior were also observed.
    Matched MeSH terms: Organic Chemicals/metabolism; Organic Chemicals/chemistry*
  3. Soda W, Noble AD, Suzuki S, Simmons R, Sindhusen LA, Bhuthorndharaj S
    J Environ Qual, 2006 Oct 27;35(6):2293-301.
    PMID: 17071900
    Acid waste bentonite is a byproduct from vegetable oil bleaching that is acidic (pH < 3.0) and hydrophobic. These materials are currently disposed of in landfills and could potentially have a negative impact on the effective function of microbes that are intolerant of acidic conditions. A study was undertaken using three different sources of acid waste bentonites, namely soybean oil bentonite (SB), palm oil bentonite (PB), and rice bran oil bentonite (RB). These materials were co-composted with rice husk, rice husk ash, and chicken litter to eliminate their acid reactivity and hydrophobic nature. The organic carbon (OC) content, pH, exchangeable cations, and cation exchange capacity (CEC) of the acid-activated bentonites increased significantly after the co-composting phase. In addition, the hydrophobic nature of these materials as measured using the water drop penetration time (WDPT) decreased from >10 800 s to 16 to 80 s after composting. Furthermore, these composted materials showed positive impacts on soil physical attributes including specific surface area, bulk density, and available water content for crop growth. Highly significant increases in maize biomass (Zea mays L.) production over two consecutive cropping cycles was observed in treatments receiving co-composted bentonite. The study clearly demonstrates the potential for converting an environmentally hazardous material into a high-quality soil conditioner using readily available agricultural byproducts. It is envisaged that the application of these composted acid waste bentonites to degraded soils will increase productivity and on-farm income, thus contributing toward food security and poverty alleviation.
    Matched MeSH terms: Organic Chemicals/metabolism; Organic Chemicals/chemistry
  4. Fulazzaky MA
    Bioprocess Biosyst Eng, 2013 Jan;36(1):11-21.
    PMID: 22622964 DOI: 10.1007/s00449-012-0756-7
    Anaerobic treatment processes to remove organic matter from palm oil mill effluent (POME) have been used widely in Malaysia. Still the amounts of total organic and total mineral released from POME that may cause degradation of the receiving environment need to be verified. This paper proposes the use of the hydrodynamic equations to estimate performance of the cascaded anaerobic ponds (CAP) and to calculate amounts of total organic matter and total mineral released from POME. The CAP efficiencies to remove biochemical oxygen demands, chemical oxygen demands, total solids and volatile solids (VS) as high as 94.5, 93.6, 96.3 and 98.2 %, respectively, are estimated. The amounts of total organic matter and total mineral as high as 538 kg VS/day and 895 kg FS/day, respectively, released from POME to the receiving water are calculated. The implication of the proposed hydrodynamic equations contributes to more versatile environmental assessment techniques, sometimes replacing laboratory analysis.
    Matched MeSH terms: Organic Chemicals/analysis*; Organic Chemicals/metabolism
  5. Ibrahim WA, Nodeh HR, Sanagi MM
    Crit Rev Anal Chem, 2016 Jul 03;46(4):267-83.
    PMID: 26186420 DOI: 10.1080/10408347.2015.1034354
    Graphene is a new carbon-based material that is of interest in separation science. Graphene has extraordinary properties including nano size, high surface area, thermal and chemical stability, and excellent adsorption affinity to pollutants. Its adsorption mechanisms are through non-covalent interactions (π-π stacking, electrostatic interactions, and H-bonding) for organic compounds and covalent interactions for metal ions. These properties have led to graphene-based material becoming a desirable adsorbent in a popular sample preparation technique known as solid phase extraction (SPE). Numerous studies have been published on graphene applications in recent years, but few review papers have focused on its applications in analytical chemistry. This article focuses on recent preconcentration of trace elements, organic compounds, and biological species using SPE-based graphene, graphene oxide, and their modified forms. Solid phase microextraction and micro SPE (µSPE) methods based on graphene are discussed.
    Matched MeSH terms: Organic Chemicals/isolation & purification*; Organic Chemicals/chemistry
  6. Haque ST, Chowdhury EH
    Curr Drug Deliv, 2018;15(4):485-496.
    PMID: 29165073 DOI: 10.2174/1567201814666171120114034
    BACKGROUND: Delivery of conventional small molecule drugs and currently evolving nucleic acid-based therapeutics, such as small interfering RNAs (siRNAs) and genes, and contrast agents for high resolution imaging, to the target site of action is highly demanding to increase the therapeutic and imaging efficacy while minimizing the off-target effects of the delivered molecules, as well as develop novel therapeutic and imaging approaches.

    METHODS: We have undertaken a structured search for peer-reviewed research and review articles predominantly indexed in PubMed focusing on the organic-inorganic hybrid nanoparticles with evidence of their potent roles in intracellular delivery of therapeutic and imaging agents in different animal models.

    RESULTS: Organic-inorganic hybrid nanoparticles offer a number of advantages by combining the unique properties of the organic and inorganic counterparts, thus improving the pharmacokinetic behavior and targetability of drugs and contrast agents, and conferring the exclusive optical and magnetic properties for both therapeutic and imaging purposes. Different polymers, lipids, dendrimers, peptides, cell membranes, and small organic molecules are attached via covalent or non-covalent interactions with diverse inorganic nanoparticles of gold, mesoporous silica, magnetic iron oxide, carbon nanotubes and quantum dots for efficient drug delivery and imaging purposes.

    CONCLUSION: We have thus highlighted here the progress made so far in utilizing different organicinorganic hybrid nanoparticles for in vivo delivery of anti-cancer drugs, siRNA, genes and imaging agents.

    Matched MeSH terms: Inorganic Chemicals/administration & dosage; Inorganic Chemicals/chemistry*; Organic Chemicals/administration & dosage; Organic Chemicals/chemistry*
  7. Abdullah SM, Ahmad Z, Sulaiman K
    Sensors (Basel), 2014;14(6):9878-88.
    PMID: 24901979 DOI: 10.3390/s140609878
    An electrochemical cell using an organic compound, copper (II) phthalocyanine-tetrasulfonic acid tetrasodium salt (CuTsPc,) has been fabricated and investigated as a solution-based temperature sensor. The capacitance and resistance of the ITO/CuTsPc solution/ITO chemical cell has been characterized as a function of temperature in the temperature range of 25-80 °C. A linear response with minimal hysteresis is observed. The fabricated temperature sensor has shown high consistency and sensitive response towards a specific range of temperature values.
    Matched MeSH terms: Organic Chemicals
  8. Ng SM, Narayanaswamy R
    Anal Chim Acta, 2011 Oct 10;703(2):226-33.
    PMID: 21889638 DOI: 10.1016/j.aca.2011.07.032
    Despite the increasing number of usage of molecularly imprinted polymers (MIPs) in optical sensor application, the correlation between the analytical signals and the binding isotherms has yet to be fully understood. This work investigates the relationship between the signals generated from MIPs sensors to its respective binding affinity variables generated using binding isotherm models. Two different systems based on the imprinting of metal ion and organic compound have been selected for the study, which employed reflectance and fluorescence sensing schemes, respectively. Batch binding analysis using the standard binding isotherm models was employed to evaluate the affinity of the binding sites. Evaluation using the discrete bi-Langmuir isotherm model found both the MIPs studied have generally two classes of binding sites that was of low and high affinities, while the continuous Freundlich isotherm model has successfully generated a distribution of affinities within the investigated analytical window. When the MIPs were incorporated as sensing receptors, the changes in the analytical signal due to different analyte concentrations were found to have direct correlation with the binding isotherm variables. Further data analyses based on this observation have generated robust models representing the analytical performance of the optical sensors. The best constructed model describing the sensing trend for each of the sensor has been tested and demonstrated to give accurate prediction of concentration for a series of spiked analytes.
    Matched MeSH terms: Organic Chemicals
  9. Dasineh Khiavi N, Katal R, Kholghi Eshkalak S, Masudy-Panah S, Ramakrishna S, Jiangyong H
    Nanomaterials (Basel), 2019 Jul 13;9(7).
    PMID: 31337085 DOI: 10.3390/nano9071011
    A high recombination rate and low charge collection are the main limiting factors of copper oxides (cupric and cuprous oxide) for the photocatalytic degradation of organic pollutants. In this paper, a high performance copper oxide photocatalyst was developed by integrating cupric oxide (CuO) and cuprous oxide (Cu2O) thin films, which showed superior performance for the photocatalytic degradation of methylene blue (MB) compared to the control CuO and Cu2O photocatalyst. Our results show that a heterojunction photocatalyst of CuO-Cu2O thin films could significantly increase the charge collection, reduce the recombination rate, and improve the photocatalytic activity.
    Matched MeSH terms: Organic Chemicals
  10. Lu S, Zhang Y, Zhang ZH, Tsai PC, Zhang X, Tan ST, et al.
    Front Chem, 2021;9:639023.
    PMID: 33816438 DOI: 10.3389/fchem.2021.639023
    Strain-reduced micro-LEDs in 50 μm × 50 μm, 100 μm × 100 μm, 200 μm × 200 μm, 500 μm × 500 μm, and 1,000 μm × 1,000 μm sizes were grown on a patterned c-plane sapphire substrate using partitioned growth with the metal-organic chemical-vapor deposition (MOCVD) technique. The size effect on the optical properties and the indium concentration for the quantum wells were studied experimentally. Here, we revealed that the optical properties can be improved by decreasing the chip size (from 1,000 to 100 µm), which can correspondingly reduce the in-plane compressive stress. However, when the chip size is further reduced to 50 μm × 50 μm, the benefit of strain release is overridden by additional defects induced by the higher indium incorporation in the quantum wells and the efficiency of the device decreases. The underlying mechanisms of the changing output power are uncovered based on different methods of characterization. This work shows the rules of thumb to achieve optimal power performance for strain-reduced micro-LEDs through the proposed partitioned growth process.
    Matched MeSH terms: Organic Chemicals
  11. Aznin Baharudin, Nor Akmalazura Jani, Azyati Azreen, A. A. Assyura, Hawa Pornomo, M. Hafiz Mehat
    Borneo Akademika, 2020;4(1):1-12.
    MyJurnal
    This study is focused on formulating a natural-based fabric softener using baking
    soda and vinegar with the addition of insect repellent finish of citronella oil and
    vanillin. The effectiveness of the fabric softener was evaluated by conducting a fabric
    stiffness test on both untreated and treated fabric samples with the softener
    formulated in this study. The assessment for the efficacy of insect repellence was
    carried out using 3 human participants of the same gender and build but different
    blood type, positioned at a mosquito infested area. Three tests; negative, positive, and
    normal tests were conducted to evaluate the effectiveness of the formulated mosquito
    repellent finishes in the fabric softener. The results show that the formulated fabric
    softener is good mosquito repellent and it is good at giving a soft effect on the treated
    fabric.
    Matched MeSH terms: Organic Chemicals
  12. Ravee R, Baharin A, Cho WT, Ting TY, Goh HH
    Physiol Plant, 2021 Dec;173(4):1967-1978.
    PMID: 34455610 DOI: 10.1111/ppl.13540
    Nepenthes ampullaria is a unique carnivorous tropical pitcher plant with the detritivorous capability of sequestering nutrients from leaf litter apart from being insectivorous. The changes in the protein composition and protease activity of its pitcher fluids during the early opening of pitchers (D0 and D3C) were investigated via a proteomics approach and a controlled protein depletion experiment (D3L). A total of 193 proteins were identified. Common proteins such as pathogenesis-related protein, proteases (Nep [EC:3.4.23.12], SCP [EC:3.4.16.-]), peroxidase [EC:1.11.1.7], GDSL esterase/lipase [EC:3.1.1.-], and purple acid phosphatase [EC:3.1.3.2] were found in high abundance in the D0 pitchers and were replenished in D3L samples. This reflects their importance for biological processes upon pitcher opening. Meanwhile, prey-inducible chitinases [EC:3.2.1.14] were found in D0 but not in D3C and D3L samples, which suggests their degradation in the absence of prey. Protease activity assays demonstrated the replenishment of proteases in D3L with similar levels of proteolytic activities to that of D3C samples. This supports a feedback mechanism and signaling in the molecular regulation of endogenous protein secretion, turnover, and activity in Nepenthes pitcher fluids. Furthermore, we also discovered several new enzymes (XTH [EC:2.4.1.207], PAE [EC:3.1.1.98]) with possible functions in cell wall degradation that could contribute to the detritivory habit of N. ampullaria.
    Matched MeSH terms: Organic Chemicals
  13. Shah I, Adnan R, Ngah WS, Mohamed N, Taufiq-Yap YH
    Bioresour Technol, 2014 May;160:52-6.
    PMID: 24630369 DOI: 10.1016/j.biortech.2014.02.047
    To enhance the potential of activated carbon (AC), iron incorporation into the AC surface was examined in the present investigations. Iron doped activated carbon (FeAC) material was synthesized and characterized by using surface area analysis, energy dispersive X-ray (EDX), temperature programmed reduction (TPR) and temperature programmed desorption (TPD). The surface area of FeAC (543 m(2)/g) was found to be lower than AC (1043 m(2)/g) as a result of the pores widening due to diffusion of iron particles into the porous AC. Iron uploading on AC surface was confirmed through EDX analysis, showing up to 13.75 wt.% iron on FeAC surface. TPR and TPD profiles revealed the presence of more active sites on FeAC surface. FeAC have shown up to 98% methylene blue (MB) removal from the aqueous media. Thermodynamic parameters indicated the spontaneous and exothermic nature of the sorption processes.
    Matched MeSH terms: Organic Chemicals/isolation & purification*
  14. Ng CA, Sun D, Bashir MJ, Wai SH, Wong LY, Nisar H, et al.
    Bioresour Technol, 2013 Jun;138:38-47.
    PMID: 23612160 DOI: 10.1016/j.biortech.2013.03.129
    It was found that with replenishment, powdered activated carbon (PAC) in the membrane bioreactor (MBR) would develop biologically activated carbon (BAC) which could enhance filtration performance of a conventional MBR. This paper addresses two issues (i) effect of PAC size on MBR (BAC) performance; and (ii) effect of sludge retention time (SRT) on the MBR performance with and without PAC. To interpret the trends, particle/floc size, concentration of mixed liquor suspended solid (MLSS), total organic carbon (TOC), short-term filtration properties and transmembrane pressure (TMP) versus time are measured. The results showed improved fouling control with fine, rather than coarse, PAC provided the flux did not exceed the deposition flux for the fine PAC. Without PAC, the longer SRT operation gave lower fouling at modest fluxes. With PAC addition, the shorter SRT gave better fouling control, possibly due to greater replenishment of the fresh PAC.
    Matched MeSH terms: Organic Chemicals/analysis
  15. Sanagi MM, Ling SL, Nasir Z, Hermawan D, Ibrahim WA, Abu Naim A
    J AOAC Int, 2010 2 20;92(6):1833-8.
    PMID: 20166602
    LOD and LOQ are two important performance characteristics in method validation. This work compares three methods based on the International Conference on Harmonization and EURACHEM guidelines, namely, signal-to-noise, blank determination, and linear regression, to estimate the LOD and LOQ for volatile organic compounds (VOCs) by experimental methodology using GC. Five VOCs, toluene, ethylbenzene, isopropylbenzene, n-propylbenzene, and styrene, were chosen for the experimental study. The results indicated that the estimated LODs and LOQs were not equivalent and could vary by a factor of 5 to 6 for the different methods. It is, therefore, essential to have a clearly described procedure for estimating the LOD and LOQ during method validation to allow interlaboratory comparisons.
    Matched MeSH terms: Organic Chemicals/analysis*
  16. Abdullah AZ, Bakar MZ, Bhatia S
    J Hazard Mater, 2006 Feb 28;129(1-3):39-49.
    PMID: 16310938
    The paper reports on the performance of chromium or/and copper supported on H-ZSM-5(Si/Al = 240) modified with silicon tetrachloride (Cr1.5/SiCl4-Z, Cu1.5/SiCl4-Z and Cr1.0Cu0.5/SiCl4-Z) as catalysts in the combustion of chlorinated VOCs (Cl-VOCs). A reactor operated at a gas hourly space velocity (GHSV) of 32,000 h(-1), a temperature between 100 and 500 degrees C with 2500 ppm of dichloromethane (DCM), trichloromethane (TCM) and trichloroethylene (TCE) is used for activity studies. The deactivation study is conducted at a GHSV of 3800 h(-1), at 400 degrees C for up to 12 h with a feed concentration of 35,000 ppm. Treatment with silicon tetrachloride improves the chemical resistance of H-ZSM-5 against hydrogen chloride. TCM is more reactive compared to DCM but it produces more by-products due to its high chlorine content. The stabilization of TCE is attributed to resonance effects. Water vapor increases the carbon dioxide yield through its role as hydrolysis agent forming reactive carbocations and acting as hydrogen-supplying agent to suppress chlorine-transfer reactions. The deactivation of Cr1.0Cu0.5/SiCl4-Z is mainly due to the chlorination of its metal species, especially with higher Cl/H feed. Coking is limited, particularly with DCM and TCM. In accordance with the Mars-van Krevelen model, the weakening of overall metal reducibility due to chlorination leads to a loss of catalytic activity.
    Matched MeSH terms: Organic Chemicals/chemistry*
  17. Din MF, Ponraj M, Low WP, Fulazzaky MA, Iwao K, Songip AR, et al.
    Water Environ Res, 2016 Feb;88(2):118-30.
    PMID: 26803100 DOI: 10.2175/106143015X14362865227913
    In this study, the removal of natural organic matter (NOM) using coconut fiber (CF) and palm oil fiber (POF) was investigated. Preliminary analysis was performed using a jar test for the selection of optimal medium before the fabricated column model experiment. The equilibrium studies on isotherms and kinetic models for NOM adsorption were analyzed using linearized correlation coefficient. Results showed that the equilibrium data were fitted to Langmuir isotherm model for both CF and POF. The most suitable adsorption model was the pseudo-first-order kinetic model for POF and pseudo-second-order kinetic model for CF. The adsorption capacities achieved by the CF and POF were 15.67 and 30.8 mg/g respectively. Based on this investigation, it can be concluded that the POF is the most suitable material for the removal of NOM in semi polluted river water.
    Matched MeSH terms: Organic Chemicals/isolation & purification*
  18. Ahmad UK, Ulang Z, Yusop Z, Fong TL
    Water Sci Technol, 2002;46(9):117-25.
    PMID: 12448460
    The complex nature of natural organic matter (NOM), and the impact of this matter on drinking water quality have necessitated the characterization studies of NOM. A fluorescence technique for the characterization of NOM in Malaysian river water is reported. Water samples from several river sampling sites were collected and concentrated using a low-pressure reverse osmosis (LPROM). Solid phase extraction (SPE) using C18 extraction cartridges were used to fractionate the water samples into humic and non-humic fractions. To differentiate and classify various types of humic substances, fluorescence was applied in emission, excitation and in synchronous-scan modes. A synchronous spectral profile was found to be able to differentiate humic and fulvic acids better than the emission or excitation spectra. Synchronous excitation spectra showed different spectral patterns for the water samples due to different origin. All water samples showed the presence of both fulvic and humic acids.
    Matched MeSH terms: Organic Chemicals/analysis
  19. Ujang Z, Salim MR, Khor SL
    Water Sci Technol, 2002;46(9):193-200.
    PMID: 12448469
    A laboratory-scale membrane bioreactor (MBR) was fed with synthetic wastewater to investigate the possibility of simultaneous removal of organic, nitrogen and phosphorus by intermittent aeration. The MBR consists of two compartments using a microfiltration membrane with 0.2 microm pore size and a surface area of 0.35 m2. Hydraulic retention time was set at 24 hours and solid retention time 25 days. MLSS concentration in the reactor was in the range of 2,500-3,800 mg/L. The MLSS internal recycling ratio was maintained at 100% influent flow rate. Intermittent aeration was applied in this study to provide an aerobic-anaerobic cycle. Three stages of operations were conducted to investigate the effect of aeration and non-aeration on simultaneous organic and nutrient removal. In Stage 1, time cycles of aeration and non-aeration were set at 90/150 min and 150/90 min in the first and second compartment, the removal efficiency was 97%, 94% and 70% for COD, nitrogen and phosphorus respectively. In Stage 2, time cycles of aeration and non-aeration were set at 60/120 min and 120/60 min in the first and second compartment, the removal efficiency was 97%, 96% and 71% for COD, nitrogen and phosphorus respectively. In Stage 3, time cycles of aeration and non-aeration were set at 120/120 min and 120/120 min in compartment 1 and 2, the removal efficiency was 98%, 96% and 78% for COD, nitrogen and phosphorus respectively. Results show that longer non-aeration time in the second compartment provided better performances of biological phosphorus removal.
    Matched MeSH terms: Organic Chemicals/isolation & purification
  20. Jusoh AB, Noor MJ, Plow SB
    Water Sci Technol, 2002;46(9):127-35.
    PMID: 12448461
    The removal of natural organic matter (NOM) using a continuous flow fixed bed granular activated carbon (GAC) column was studied and the results were then fitted with the Adams-Bohart, Bed-Depth-Service-Time and Clarks models. The GAC, KI-6070 and KI-8085 used in the study had external surface areas of 277 m2/g and 547 m2/g, respectively. Adsorption of NOM by the GAC was complex and involved more than one rate-limiting step. The critical bed depths for KI-6070 and KI-8085 were 0.24 m and 0.3 m, respectively. The Clark model was more effective in simulating the absorbent breakthrough process as compared to the Adams-Bohart model. The lower empty bed contact time (EBCT) i.e. 15 minutes gave a better fit to the Clark Model as compared to EBCT of 20 and 30 minutes.
    Matched MeSH terms: Organic Chemicals/isolation & purification
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links