Displaying publications 261 - 280 of 665 in total

Abstract:
Sort:
  1. Fulltext Statistical optimization of process parameters for lipase-catalyzed synthesis of triethanolamine-based esterquats using response surface methodology in 2-liter bioreactor
    Masoumi HR, Basri M, Kassim A, Abdullah DK, Abdollahi Y, Abd Gani SS, et al.
    ScientificWorldJournal, 2013;2013:962083.
    PMID: 24324389 DOI: 10.1155/2013/962083
    Lipase-catalyzed production of triethanolamine-based esterquat by esterification of oleic acid (OA) with triethanolamine (TEA) in n-hexane was performed in 2 L stirred-tank reactor. A set of experiments was designed by central composite design to process modeling and statistically evaluate the findings. Five independent process variables, including enzyme amount, reaction time, reaction temperature, substrates molar ratio of OA to TEA, and agitation speed, were studied under the given conditions designed by Design Expert software. Experimental data were examined for normality test before data processing stage and skewness and kurtosis indices were determined. The mathematical model developed was found to be adequate and statistically accurate to predict the optimum conversion of product. Response surface methodology with central composite design gave the best performance in this study, and the methodology as a whole has been proven to be adequate for the design and optimization of the enzymatic process.
    Matched MeSH terms: Analysis of Variance
  2. Fulltext Cytotoxicity and genotoxicity assessment of Euphorbia hirta in MCF-7 cell line model using comet assay
    Ping KY, Darah I, Chen Y, Sasidharan S
    Asian Pac J Trop Biomed, 2013 Sep;3(9):692-6.
    PMID: 23998008 DOI: 10.1016/S2221-1691(13)60140-9
    To evaluate the cytotoxicity and genotoxicity activity of Euphorbia hirta (E. hirta) in MCF-7 cell line model using comet assay.
    Matched MeSH terms: Analysis of Variance
  3. Fulltext Intracanal placement of calcium hydroxide: a comparison of specially designed paste carrier technique with other techniques
    Tan JM, Parolia A, Pau AK
    BMC Oral Health, 2013;13:52.
    PMID: 24098931 DOI: 10.1186/1472-6831-13-52
    This study compared the effectiveness of a Specially Designed Paste Carrier technique with the Syringe-Spreader technique and the Syringe-Lentulo spiral technique in the intracanal placement of calcium hydroxide.
    Matched MeSH terms: Analysis of Variance
  4. Responsibility attribution of HIV infection and coping among injection drug users in Malaysia
    Chou CC, Chronister J, Chou CH, Tan S, Macewicz T
    AIDS Care, 2013;25(12):1551-8.
    PMID: 23713718 DOI: 10.1080/09540121.2013.793267
    This study explored responsibility attribution (RA) of HIV/AIDS infection (i.e., how an individual perceives the cause of their HIV/AIDS infection) and its relationship to coping styles among injection drug users (IDUs) with HIV/AIDS. In addition, this study investigated whether self-esteem, social support, and religiosity mediate the relationship between RA and coping styles of IDUs with HIV/AIDS. Participants were 201 adult IDUs with HIV/AIDS participating in the National Drug Rehabilitation Center in Malaysia. Five measures were used to assess the above constructs. Cluster analysis, analysis of variance, and mediation analyses were conducted. Results of this study indicated that IDUs with HIV/AIDS in Malaysia can be classified into four homogenous attribution groups: external, fatalistic, internal, and indeterminate. Mediator analyses revealed that combination of self-esteem, social support, and religiosity mediate the relationship between RA and coping behaviors. Clinicians working with IDUs with HIV/AIDS need to address the role of RA, self-esteem, religiosity, and social support as these psychosocial constructs are linked to coping with HIV/AIDS. Future researchers should investigate whether enhancing self-esteem, social support, and religiosity can promote active problem-solving coping and reduce the use of avoidance coping behaviors.
    Matched MeSH terms: Analysis of Variance
  5. Fulltext Long-term trends in calcifying plankton and pH in the North Sea
    Beare D, McQuatters-Gollop A, van der Hammen T, Machiels M, Teoh SJ, Hall-Spencer JM
    PLoS One, 2013;8(5):e61175.
    PMID: 23658686 DOI: 10.1371/journal.pone.0061175
    Relationships between six calcifying plankton groups and pH are explored in a highly biologically productive and data-rich area of the central North Sea using time-series datasets. The long-term trends show that abundances of foraminiferans, coccolithophores, and echinoderm larvae have risen over the last few decades while the abundances of bivalves and pteropods have declined. Despite good coverage of pH data for the study area there is uncertainty over the quality of this historical dataset; pH appears to have been declining since the mid 1990s but there was no statistical connection between the abundance of the calcifying plankton and the pH trends. If there are any effects of pH on calcifying plankton in the North Sea they appear to be masked by the combined effects of other climatic (e.g. temperature), chemical (nutrient concentrations) and biotic (predation) drivers. Certain calcified plankton have proliferated in the central North Sea, and are tolerant of changes in pH that have occurred since the 1950s but bivalve larvae and pteropods have declined. An improved monitoring programme is required as ocean acidification may be occurring at a rate that will exceed the environmental niches of numerous planktonic taxa, testing their capacities for acclimation and genetic adaptation.
    Matched MeSH terms: Analysis of Variance
  6. Microwave assisted biodiesel production from Jatropha curcas L. seed by two-step in situ process: optimization using response surface methodology
    Jaliliannosrati H, Amin NA, Talebian-Kiakalaieh A, Noshadi I
    Bioresour Technol, 2013 May;136:565-73.
    PMID: 23567732 DOI: 10.1016/j.biortech.2013.02.078
    The synthesis of fatty acid ethyl esters (FAEEs) by a two-step in situ (reactive) esterification/transesterification from Jatropha curcas L. (JCL) seeds using microwave system has been investigated. Free fatty acid was reduced from 14% to less than 1% in the first step using H2SO4 as acid catalyst after 35 min of microwave irradiation heating. The organic phase in the first step was subjected to a second reaction by adding 5 N KOH in ethanol as the basic catalyst. Response surface methodology (RSM) based on central composite design (CCD) was utilized to design the experiments and analyze the influence of process variables (particles seed size, time of irradiation, agitation speed and catalyst loading) on conversion of triglycerides (TGs) in the second step. The highest triglycerides conversion to fatty acid ethyl esters (FAEEs) was 97.29% at the optimum conditions:<0.5mm seed size, 12.21 min irradiation time, 8.15 ml KOH catalyst loading and 331.52 rpm agitation speed in the 110 W microwave power system.
    Matched MeSH terms: Analysis of Variance
  7. Optimization of stabilized leachate treatment using ozone/persulfate in the advanced oxidation process
    Abu Amr SS, Aziz HA, Adlan MN
    Waste Manag, 2013 Jun;33(6):1434-41.
    PMID: 23498721 DOI: 10.1016/j.wasman.2013.01.039
    The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH3-N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210 min, 30 g/m(3) ozone, 1g/1g COD0/S2O8(2-) ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH3-N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O3/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate S2O8(2-) only, to evaluate its effectiveness. The combined method (i.e., O3/S2O8(2-)) achieved higher removal efficiencies for COD, color, and NH3-N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate.
    Matched MeSH terms: Analysis of Variance
  8. Optimization of levulinic acid from lignocellulosic biomass using a new hybrid catalyst
    Ya'aini N, Amin NA, Asmadi M
    Bioresour Technol, 2012 Jul;116:58-65.
    PMID: 22609656 DOI: 10.1016/j.biortech.2012.03.097
    Conversion of glucose, empty fruit bunch (efb) and kenaf to levulinic acid over a new hybrid catalyst has been investigated in this study. The characterization and catalytic performance results revealed that the physico-chemical properties of the new hybrid catalyst comprised of chromium chloride and HY zeolite increased the levulinic acid production from glucose compared to the parent catalysts. Optimization of the glucose conversion process using two level full factorial designs (2(3)) with two center points reported 55.2% of levulinic acid yield at 145.2 °C, 146.7 min and 12.0% of reaction temperature, reaction time and catalyst loading, respectively. Subsequently, the potential of efb and kenaf for producing levulinic acid at the optimum conditions was established after 53.2% and 66.1% of efficiencies were reported. The observation suggests that the hybrid catalyst has a potential to be used in biomass conversion to levulinic acid.
    Matched MeSH terms: Analysis of Variance
  9. Participating in a virtual reality balance exercise program can reduce risk and fear of falls
    Singh DK, Rajaratnam BS, Palaniswamy V, Pearson H, Raman VP, Bong PS
    Maturitas, 2012 Nov;73(3):239-43.
    PMID: 22884437 DOI: 10.1016/j.maturitas.2012.07.011
    The objective of this study was to quantify the effectiveness of virtual reality balance games (VRBG) to decrease risk and fear of falls among women.
    Matched MeSH terms: Analysis of Variance
  10. Effects of balance-focused interactive games compared to therapeutic balance classes for older women
    Singh DK, Rajaratnam BS, Palaniswamy V, Raman VP, Bong PS, Pearson H
    Climacteric, 2013 Feb;16(1):141-6.
    PMID: 22640573 DOI: 10.3109/13697137.2012.664832
    The prospective pre-post control study was designed to evaluate the effect of introducing balance-focused interactive virtual-reality games to community-dwelling older women to improve their agility, balance and functional mobility.
    Matched MeSH terms: Analysis of Variance
  11. Fulltext Quality of life after haematopoietic stem cell transplantation in a multiracial population
    Bee PC, Gan GG, Sangkar VJ, Haris AR, Chin E
    Med J Malaysia, 2011 Dec;66(5):451-5.
    PMID: 22390100 MyJurnal
    Haematopoietic stem cell transplantation (HSCT) was started in Malaysia since 1993 and it has improved the survival of patients with otherwise fatal haematological diseases. This study was initiated because quality of life of these survivors is an important tool in assessing the outcome of this treatment modality. The secondary objective was to identify factors that influenced their quality of life. The European Organization of Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-30) was used to assess the quality of life of eligible patients. A total of 62 patents were recruited. The mean global health score (QoL) was 71.2. The major symptoms faced by our patients were fatigue, financial difficulty and appetite loss. Appetite loss was an independent adverse factor for lower QoL.
    Matched MeSH terms: Analysis of Variance
  12. Evaluation of splinting implant impression techniques: two dimensional analyses
    Tarib NA, Seong TW, Chuen KM, Kun MS, Ahmad M, Kamarudin KH
    Eur J Prosthodont Restor Dent, 2012 Mar;20(1):35-9.
    PMID: 22474935
    This paper aims to evaluate the effect of splinting during implant impression. A master model with two fixtures at the sites of 45 and 47 was used. 20 impressions were made for all four techniques: (A) indirect; (B) direct, unsplinted; (C) direct, splinted; and (D) direct, splinted, sectioned, and re-splinted. Splinting was undertaken with autopolymerizing acrylic resin (AAR). Horizontal distance between fixtures was compared using a digital caliper. The difference in distance were analysed with one-way ANOVA. Group A showed a significantly lowest accuracy among all techniques (p < or = 0.05). There was no significant difference of accuracy among the groups using direct techniques (p > or = 0.05). Group D was more accurate compared to group B and C. We conclude that splinting of impression copings would be beneficial to obtain an accurate impression.
    Matched MeSH terms: Analysis of Variance
  13. Improved cellulase production by Botryosphaeria rhodina from OPEFB at low level moisture condition through statistical optimization
    Bahrin EK, Ibrahim MF, Abd Razak MN, Abd-Aziz S, Shah UK, Alitheen N, et al.
    Prep Biochem Biotechnol, 2012;42(2):155-70.
    PMID: 22394064 DOI: 10.1080/10826068.2011.585413
    The response surface method was applied in this study to improve cellulase production from oil palm empty fruit bunch (OPEFB) by Botryosphaeria rhodina. An experimental design based on a two-level factorial was employed to screen the significant environmental factors for cellulase production. The locally isolated fungus Botryosphaeria rhodina was cultivated on OPEFB under solid-state fermentation (SSF). From the analysis of variance (ANOVA), the initial moisture content, amount of substrate, and initial pH of nutrient supplied in the SSF system significantly influenced cellulase production. Then the optimization of the variables was done using the response surface method according to central composite design (CCD). Botryosphaeria rhodina exhibited its best performance with a high predicted value of FPase enzyme production (17.95 U/g) when the initial moisture content was at 24.32%, initial pH of nutrient was 5.96, and 3.98 g of substrate was present. The statistical optimization from actual experiment resulted in a significant increment of FPase production from 3.26 to 17.91 U/g (5.49-fold). High cellulase production at low moisture content is a very rare condition for fungi cultured in solid-state fermentation.
    Matched MeSH terms: Analysis of Variance
  14. Fulltext Antioxidant and antiangiogenic activities of the essential oils of Myristica fragrans and Morinda citrifolia
    Piaru SP, Mahmud R, Abdul Majid AM, Mahmoud Nassar ZD
    Asian Pac J Trop Med, 2012 Apr;5(4):294-8.
    PMID: 22449521 DOI: 10.1016/S1995-7645(12)60042-X
    OBJECTIVE: Toinvestigate the anti-angiogenic activity and antioxidant properties of Myristica fragrans (M. fragrans) (nutmeg) and Morinda citrifolia (M. citrifolia)(mengkudu) oils.

    METHODS: The nutmeg and megkudu essential oils were obtained by steam distillation. The antioxidant activities of both essential oils were determined by beta-carotene/linoleic acid bleaching assay and reducing power while the anti-angiogenic activity was investigated using rat aortic ring assay using various concentrations.

    RESULTS: The results showed that nutmeg oil has higher antioxidant activity than mengkudu oil. The nutmeg oil effectively inhibited the oxidation of linoleic acid with (88.68±0.1)% while the inhibition percentage of oxidation of linoleic acid of the mengkudu oil is (69.44±0.4)%. The nutmeg oil and mengkudu oil showed reducing power with an EC(50) value of 181.4 μg/mL and 3 043.0 μg/mL, respectively. The antiangiogenic activity of nutmeg oil showed significant antiangiogenic activity with IC(50) of 77.64 μg/mL comparing to mengkudu oil which exhibits IC(50) of 109.30 μg/mL.

    CONCLUSIONS: Bioactive compound(s) will be isolated from the nutmeg essential oil to be developed as antiangiogenic drugs.

    Matched MeSH terms: Analysis of Variance
  15. Fulltext Combining ability analysis in complete diallel cross of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai)
    Bahari M, Rafii MY, Saleh GB, Latif MA
    ScientificWorldJournal, 2012;2012:543158.
    PMID: 22566772 DOI: 10.1100/2012/543158
    The experiments were carried out in two research stations (MARDI Bukit Tangga, Kedah, and MARDI Seberang Perai, Penang) in Malaysia. The crossings were performed using the four inbred lines in complete diallel cross including selfs and reciprocals. We evaluated the yield components and fruit characters such as fruit yield per plant, vine length, days to fruit maturity, fruit weight, total soluble solid content, and rind thickness over a period of two planting seasons. General combining ability and its interaction with locations were statistically significant for all characteristics except number of fruits per plant across the environments. Results indicated that the additive genetic effects were important to the inheritance of these traits and the expression of additive genes was influenced greatly by environments. In addition, specific combining ability effect was statistically evident for fruit yield per plant, vine length, days to first female flower, and fruit weight. Most of the characters are simultaneously controlled by additive and nonadditive gene effects. This study demonstrated that the highest potential and promising among the crosses was cross P2 (BL-14) × P3 (6372-4), which possessed prolific plants, with early maturity, medium fruit weight and high soluble solid contents. Therefore this hybrid might be utilized for developing high yielding watermelon cultivars and may be recommended for commercial cultivation.
    Matched MeSH terms: Analysis of Variance
  16. Comparative study of various pretreatment reagents on rice husk and structural changes assessment of the optimized pretreated rice husk
    Ang TN, Ngoh GC, Chua AS
    Bioresour Technol, 2013 May;135:116-9.
    PMID: 23138072 DOI: 10.1016/j.biortech.2012.09.045
    The performance of alkalis (NaOH and Ca(OH)2) and acids (H2SO4, HCl, H3PO4, CH3COOH, and HNO3) in the pretreatment of rice husk was screened, and a suitable reagent was assessed for subsequent optimization using response surface methodology. From the assessment, HCl that hydrolysed rice husk well was optimized with three parameters (HCl loading, pretreatment duration, and temperature) using Box-Behnken Design. The optimized condition (0.5% (w/v) HCl loading, 125 °C, 1.5 h) is relatively mild, and resulted in ~22.3mg TRS/ml hydrolysate. The reduced model developed has good predictability, where the predicted and experimental results differ by only 2%. The comprehensive structural characterization studies that involved FT-IR, XRD, SEM, and BET surface area determination showed that the pretreated rice husk consisted mainly of cellulose and lignin. Compared to untreated rice husk, pretreated rice husk possessed increased pore size and pore volume, which are expected to be beneficial for fungal growth during fermentation.
    Matched MeSH terms: Analysis of Variance
  17. Ovarian development of a river catfish Hemibagrus nemurus (Valenciennes, 1840) in captivity
    Adebiyi FA, Siraj SS, Harmin SA, Christianus A
    J Exp Zool A Ecol Genet Physiol, 2011 Nov 1;315(9):536-43.
    PMID: 21898849 DOI: 10.1002/jez.702
    Hemibagrus nemurus is a riverine catfish with high economic and nutritive values. Investigations on ovarian development of this fish were carried out to determine the mode of ovarian development and describe the oocyte developmental stages. Histological studies were done on ovaries using light microscopy and scanning electron microscopy. Fish were sampled monthly for a period of six months (August 2009 to January 2010). The mean oocyte diameter (OD) ranged from 871 ± 161.41 µm to 1,167 ± 26.77 µm and the highest OD was in November. Oocyte size-frequency distribution showed a polymodal distribution. The mean gonadosomatic index (GSI) ranged from 1.14 ± 0.87% to 7.06 ± 1.40% and highest GSI was in November. The ovaries exhibited three phases of oocyte growth, which were primary growth, secondary growth and maturation phases. Based on histological criteria, the oocyte developmental stages were divided into seven stages as chromatin nucleolar, early perinucleolar, late perinucleolar, cortical alveolar, vitellogenesis, mature oocyte and germinal vesicle migration stages. All the seven stages of oocyte development were observed in the ovaries. Oogonia were always present throughout the developmental stages. The ovaries had more than two stages of oocyte development. This is the first report on the mode of ovarian development of H. nemurus. These findings indicated that H. nemurus has asynchronous mode of ovarian development and is capable of spawning several times in a year under favourable conditions.
    Matched MeSH terms: Analysis of Variance
  18. Screening of factors influencing Cu(II) extraction by soybean oil-based organic solvents using fractional factorial design
    Chang SH, Teng TT, Ismail N
    J Environ Manage, 2011 Oct;92(10):2580-5.
    PMID: 21700383 DOI: 10.1016/j.jenvman.2011.05.025
    This study aimed to identify the significant factors that give large effects on the efficiency of Cu(II) extraction from aqueous solutions by soybean oil-based organic solvents using fractional factorial design. Six factors (mixing time (t), di-2-ethylhexylphosphoric acid concentration ([D2EHPA]), organic to aqueous phase ratio (O:A), sodium sulfate concentration ([Na(2)SO(4)]), equilibrium pH (pH(eq)) and tributylphosphate concentration ([TBP])) affecting the percentage extraction (%E) of Cu(II) were investigated. A 2(6-1) fractional factorial design was applied and the results were analyzed statistically. The results show that only [D2EHPA], pH(eq) and their second-order interaction ([D2EHPA] × pH(eq)) influenced the %E significantly. Regression models for %E were developed and the adequacy of the reduced model was examined. The results of this study indicate that fractional factorial design is a useful tool for screening a large number of variables and reducing the number of experiments.
    Matched MeSH terms: Analysis of Variance
  19. Periodical gait asymmetry assessment using real-time wireless gyroscopes gait monitoring system
    Gouwanda D, Senanayake SM
    J Med Eng Technol, 2011 Nov;35(8):432-40.
    PMID: 22074136 DOI: 10.3109/03091902.2011.627080
    A real-time gait monitoring system that incorporates an immediate and periodical assessment of gait asymmetry is described. This system was designed for gait analysis and rehabilitation of patients with pathologic gait. It employs wireless gyroscopes to measure the angular rate of the thigh and shank in real time. Cross-correlation of the lower extremity (Cc(norm)), and normalized Symmetry Index (SI(norm)) are implemented as new approaches to periodically determine the gait asymmetry in each gait cycle. Cc(norm) evaluates the signal patterns measured by wireless gyroscopes in each gait cycle. SI(norm) determines the movement differences between the left and right limb. An experimental study was conducted to examine the viability of these methods. Artificial asymmetrical gait was simulated by placing a load on one side of the limbs. Results showed that there were significant differences between the normal gait and asymmetrical gait (p < 0.01). They also indicated that the system worked well in periodically assessing the gait asymmetry.
    Matched MeSH terms: Analysis of Variance
  20. Fulltext Optimizing supercritical antisolvent process parameters to minimize the particle size of paracetamol nanoencapsulated in L-polylactide
    Kalani M, Yunus R, Abdullah N
    Int J Nanomedicine, 2011;6:1101-5.
    PMID: 21698077 DOI: 10.2147/IJN.S18979
    The aim of this study was to optimize the different process parameters including pressure, temperature, and polymer concentration, to produce fine small spherical particles with a narrow particle size distribution using a supercritical antisolvent method for drug encapsulation. The interaction between different process parameters was also investigated.
    Matched MeSH terms: Analysis of Variance
Related Terms
Filters
Contact Us

Please provide feedback to Administrator ([email protected])

External Links