Displaying publications 61 - 80 of 390 in total

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  1. Regression methods to investigate the relationship between facial measurements and widths of the maxillary anterior teeth
    Isa ZM, Tawfiq OF, Noor NM, Shamsudheen MI, Rijal OM
    J Prosthet Dent, 2010 Mar;103(3):182-8.
    PMID: 20188241 DOI: 10.1016/S0022-3913(10)60028-5
    In rehabilitating edentulous patients, selecting appropriately sized teeth in the absence of preextraction records is problematic.
    Matched MeSH terms: Linear Models
  2. Determination of triazine herbicides using membrane-protected carbon nanotubes solid phase membrane tip extraction prior to micro-liquid chromatography
    See HH, Marsin Sanagi M, Ibrahim WA, Naim AA
    J Chromatogr A, 2010 Mar 12;1217(11):1767-72.
    PMID: 20138287 DOI: 10.1016/j.chroma.2010.01.053
    A novel microextraction technique termed solid phase membrane tip extraction (SPMTE) was developed. Selected triazine herbicides were employed as model compounds to evaluate the extraction performance and multiwall carbon nanotubes (MWCNTs) were used as the adsorbent enclosed in SPMTE device. The SPMTE procedure was performed in semi-automated dynamic mode and several important extraction parameters were comprehensively optimized. Under the optimum extraction conditions, the method showed good linearity in the range of 1-100 microg/L, acceptable reproducibility (RSD 6-8%, n=5), low limits of detection (0.2-0.5 microg/L), and satisfactory relative recoveries (95-101%). The SPMTE device could be regenerated and reused up to 15 analyses with no analyte carry-over effects observed. Comparison was made with commercially available solid phase extraction-molecular imprinted polymer cartridge (SPE-MIP) for triazine herbicides as the reference method. The new developed method showed comparable or even better results against reference method and is a simple, feasible, and cost effective microextraction technique.
    Matched MeSH terms: Linear Models
  3. Determination of underivatized long chain fatty acids using RP-HPLC with capacitively coupled contactless conductivity detection
    Makahleh A, Saad B, Siang GH, Saleh MI, Osman H, Salleh B
    Talanta, 2010 Apr 15;81(1-2):20-4.
    PMID: 20188881 DOI: 10.1016/j.talanta.2009.11.030
    A reversed-phase high-performance liquid chromatographic method with capacitively coupled contactless conductivity detector (C(4)D) has been developed for the separation and the simultaneous determination of five underivatized long chain fatty acids (FAs), namely myristic, palmitic, stearic, oleic, and linoleic acids. An isocratic elution mode using methanol/1mM sodium acetate (78:22, v/v) as mobile phase with a flow rate of 0.6 mL min(-1) was used. The separation was effected by using a Hypersil ODS C(18) analytical column (250 mm x 4.6 mm x 5 microm) and was operated at 45 degrees C. Calibration curves of the five FAs were well correlated (r(2)>0.999) within the range of 5- 200 microg mL(-1) for stearic acid, and 2-200 microg mL(-1) for the other FAs. The proposed method was tested on four vegetable oils, i.e., pumpkin, soybean, rice bran and palm olein oils; good agreement was found with the standard gas chromatographic (GC) method. The proposed method offers distinct advantages over the official GC method, especially in terms of simplicity, faster separation times and sensitivity.
    Matched MeSH terms: Linear Models
  4. Transformation of nitrogen dioxide into ozone and prediction of ozone concentrations using multiple linear regression techniques
    Ghazali NA, Ramli NA, Yahaya AS, Yusof NF, Sansuddin N, Al Madhoun WA
    Environ Monit Assess, 2010 Jun;165(1-4):475-89.
    PMID: 19440846 DOI: 10.1007/s10661-009-0960-3
    Analysis and forecasting of air quality parameters are important topics of atmospheric and environmental research today due to the health impact caused by air pollution. This study examines transformation of nitrogen dioxide (NO(2)) into ozone (O(3)) at urban environment using time series plot. Data on the concentration of environmental pollutants and meteorological variables were employed to predict the concentration of O(3) in the atmosphere. Possibility of employing multiple linear regression models as a tool for prediction of O(3) concentration was tested. Results indicated that the presence of NO(2) and sunshine influence the concentration of O(3) in Malaysia. The influence of the previous hour ozone on the next hour concentrations was also demonstrated.
    Matched MeSH terms: Linear Models*
  5. Hollow fiber liquid-phase microextraction for the determination of trace amounts of rosiglitazone (anti-diabetic drug) in biological fluids using capillary electrophoresis and high performance liquid chromatographic methods
    Al Azzam KM, Makahleah A, Saad B, Mansor SM
    J Chromatogr A, 2010 Jun 4;1217(23):3654-9.
    PMID: 20409552 DOI: 10.1016/j.chroma.2010.03.055
    A three-phase hollow fiber liquid-phase microextraction (HF-LPME) coupled either with capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with UV detection methods was successfully developed for the determination of trace levels of the anti-diabetic drug, rosiglitazone (ROSI) in biological fluids. The analyte was extracted into dihexyl ether that was immobilized in the wall pores of a porous hollow fiber from 10 mL of aqueous sample, pH 9.5 (donor phase), and was back extracted into the acceptor phase that contained 0.1M HCl located in the lumen of the hollow fiber. Parameters affecting the extraction process such as type of extraction solvent, HCl concentration, donor phase pH, extraction time, stirring speed, and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; donor phase pH, 9.5; acceptor phase, 0.1M HCl; stirring speed, 600 rpm; extraction time, 30 min; without addition of salt), enrichment factor of 280 was obtained. Good linearity and correlation coefficients of the analyte was obtained over the concentration ranges of 1.0-500 and 5.0-500 ng mL(-1) for the HPLC (r(2)=0.9988) and CE (r(2)=0.9967) methods, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for the HPLC and CE methods were (0.18, 2.83) and (0.56, 5.00) ng mL(-1), respectively. The percent relative standard deviation (n=6) for the extraction and determination of three concentration levels (10, 250, 500 ng mL(-1)) of ROSI using the HPLC and CE methods were less than 10.9% and 13.2%, respectively. The developed methods are simple, rapid, sensitive and are suitable for the determination of trace amounts of ROSI in biological fluids.
    Matched MeSH terms: Linear Models
  6. Parameters optimization of rice husk ash (RHA)/CaO/CeO2 sorbent for predicting SO2/NO sorption capacity using response surface and neural network models
    Dahlan I, Ahmad Z, Fadly M, Lee KT, Kamaruddin AH, Mohamed AR
    J Hazard Mater, 2010 Jun 15;178(1-3):249-57.
    PMID: 20137857 DOI: 10.1016/j.jhazmat.2010.01.070
    In this work, the application of response surface and neural network models in predicting and optimizing the preparation variables of RHA/CaO/CeO(2) sorbent towards SO(2)/NO sorption capacity was investigated. The sorbents were prepared according to central composite design (CCD) with four independent variables (i.e. hydration period, RHA/CaO ratio, CeO(2) loading and the use of RHA(raw) or pretreated RHA(600 degrees C) as the starting material). Among all the variables studied, the amount of CeO(2) loading had the largest effect. The response surface models developed from CCD was effective in providing a highly accurate prediction for SO(2) and NO sorption capacities within the range of the sorbent preparation variables studied. The prediction of CCD experiment was verified by neural network models which gave almost similar results to those determined by response surface models. The response surface models together with neural network models were then successfully used to locate and validate the optimum hydration process variables for maximizing the SO(2)/NO sorption capacities. Through this optimization process, it was found that maximum SO(2) and NO sorption capacities of 44.34 and 3.51 mg/g, respectively could be obtained by using RHA/CaO/CeO(2) sorbents prepared from RHA(raw) with hydration period of 12h, RHA/CaO ratio of 2.33 and CeO(2) loading of 8.95%.
    Matched MeSH terms: Linear Models
  7. MIMO model of an interacting series process for Robust MPC via System Identification
    Wibowo TC, Saad N
    ISA Trans, 2010 Jul;49(3):335-47.
    PMID: 20304404 DOI: 10.1016/j.isatra.2010.02.005
    This paper discusses the empirical modeling using system identification technique with a focus on an interacting series process. The study is carried out experimentally using a gaseous pilot plant as the process, in which the dynamic of such a plant exhibits the typical dynamic of an interacting series process. Three practical approaches are investigated and their performances are evaluated. The models developed are also examined in real-time implementation of a linear model predictive control. The selected model is able to reproduce the main dynamic characteristics of the plant in open-loop and produces zero steady-state errors in closed-loop control system. Several issues concerning the identification process and the construction of a MIMO state space model for a series interacting process are deliberated.
    Matched MeSH terms: Linear Models
  8. Lipase-catalyzed dimethyl adipate synthesis: response surface modeling and kinetics
    Chaibakhsh N, Rahman MB, Basri M, Salleh AB, Abd-Aziz S
    Biotechnol J, 2010 Aug;5(8):848-55.
    PMID: 20632329 DOI: 10.1002/biot.201000063
    Dimethyl adipate (DMA) was synthesized by immobilized Candida antarctica lipase B-catalyzed esterification of adipic acid and methanol. To optimize the reaction conditions of ester production, response surface methodology was applied, and the effects of four factors namely, time, temperature, enzyme concentration, and molar ratio of substrates on product synthesis were determined. A statistical model predicted that the maximum conversion yield would be 97.6%, at the optimal conditions of 58.5 degrees C, 54.0 mg enzyme, 358.0 min, and 12:1 molar ratio of methanol to adipic acid. The R(2) (0.9769) shows a high correlation between predicted and experimental values. The kinetics of the reaction was also investigated in this study. The reaction was found to obey the ping-pong bi-bi mechanism with methanol inhibition. The kinetic parameters were determined and used to simulate the experimental results. A good quality of fit was observed between the simulated and experimental initial rates.
    Matched MeSH terms: Linear Models
  9. Enantioselective analysis of ofloxacin and ornidazole in pharmaceutical formulations by capillary electrophoresis using single chiral selector and computational calculation of their inclusion complexes
    Al Azzam KM, Saad B, Adnan R, Aboul-Enein HY
    Anal Chim Acta, 2010 Aug 3;674(2):249-55.
    PMID: 20678638 DOI: 10.1016/j.aca.2010.06.046
    A capillary electrophoretic method for the separation of the enantiomers of both ofloxacin and ornidazole is described. Several parameters affecting the separation were studied, including the type and concentration of chiral selector, buffer pH, voltage and temperature. Good chiral separation of the racemic mixtures was achieved in less than 16 min with resolution factors Rs=5.45 and 6.28 for ofloxacin and ornidazole enantiomers, respectively. Separation was conducted using a bare fused-silica capillary and a background electrolyte (BGE) of 50 mM H(3)PO(4)-1 M tris solution; pH 1.85; containing 30 mg mL(-1) of sulfated-beta-cyclodextrin (S-beta-CD). The separation was carried out in reversed polarity mode at 25 degrees C, 18 kV, detection wavelength at 230 nm and using hydrodynamic injection for 15 s. Acceptable validation criteria for selectivity, linearity, precision, and accuracy were studied. The limits of detection (LOD) and limits of quantitation (LOQ) of the enantiomers (ofloxacin enantiomer 1 (OF-E1), ofloxacin enantiomer 2 (OF-E2), ornidazole enantiomer 1 (OR-E1) and ornidazole enantiomer 2 (OR-E2)) were (0.52, 0.46, 0.54, 0.89) and (1.59, 1.40, 3.07, 2.70) microg mL(-1), respectively. The proposed method was successfully applied to the assay of enantiomers of both ofloxacin and ornidazole in pharmaceutical formulations. The computational calculations for the enantiomeric inclusion complexes rationalized the reasons for the different migration times between the ofloxacin and ornidazole enantiomers.
    Matched MeSH terms: Linear Models
  10. Prospective randomized controlled trial evaluating cap-assisted colonoscopy vs standard colonoscopy
    Tee HP, Corte C, Al-Ghamdi H, Prakoso E, Darke J, Chettiar R, et al.
    World J Gastroenterol, 2010 Aug 21;16(31):3905-10.
    PMID: 20712051
    AIM: To study the significance of cap-fitted colonoscopy in improving cecal intubation time and polyp detection rate.

    METHODS: This study was a prospective randomized controlled trial conducted from March 2008 to February 2009 in a tertiary referral hospital at Sydney. The primary end point was cecal intubation time and the secondary endpoint was polyp detection rate. Consecutive cases of total colonoscopy over a 1-year period were recruited. Randomization into either standard colonoscopy (SC) or cap-assisted colonoscopy (CAC) was performed after consent was obtained. For cases randomized to CAC, one of the three sizes of cap was used: D-201-15004 (with a diameter of 15.3 mm), D-201-14304 (14.6 mm) and D-201-12704 (13.0 mm). All of these caps were produced by Olympus Medical Systems, Japan. Independent predictors for faster cecal time and better polyp detection rate were also determined from this study.

    RESULTS: There were 200 cases in each group. There was no significant difference in terms of demographic characteristics between the two groups. CAC, when compared to the SC group, had no significant difference in terms of cecal intubation rate (96.0% vs 97.0%, P = 0.40) and time (9.94 +/- 7.05 min vs 10.34 +/- 6.82 min, P = 0.21), or polyp detection rate (32.8% vs 31.3%, P = 0.75). On the subgroup analysis, there was no significant difference in terms of cecal intubation time by trainees (88.1% vs 84.8%, P = 0.40), ileal intubation rate (82.5% vs 79.0%, P = 0.38) or total colonoscopy time (23.24 +/- 13.95 min vs 22.56 +/- 9.94 min, P = 0.88). On multivariate analysis, the independent determinants of faster cecal time were consultant-performed procedures (P < 0.001), male patients (P < 0.001), non-usage of hyoscine (P < 0.001) and better bowel preparation (P = 0.01). The determinants of better polyp detection rate were older age (P < 0.001), no history of previous abdominal surgery (P = 0.04), patients not having esophagogastroduodenoscopy in the same setting (P = 0.003), trainee-performed procedures (P = 0.01), usage of hyoscine (P = 0.01) and procedures performed for polyp follow-up (P = 0.01). The limitations of the study were that it was a single-center experience, no blinding was possible, and there were a large number of endoscopists.

    CONCLUSION: CAC did not significantly different from SC in term of cecal intubation time and polyp detection rate.

    Matched MeSH terms: Linear Models
  11. Determination of the binding constants of modafinil enantiomers with sulfated β-cyclodextrin chiral selector by capillary electrophoresis using three different linear plotting methods
    Al Azzam KM, Saad B, Aboul-Enein HY
    Electrophoresis, 2010 Sep;31(17):2957-63.
    PMID: 20690150 DOI: 10.1002/elps.201000266
    Binding constants for the enantiomers of modafinil with the negatively charged chiral selector sulfated-β-CD (S-β-CD) using CE technique is presented. The calculations of the binding constants employing three different linearization plots (double reciprocal, X-reciprocal and Y-reciprocal) were performed from the electrophoretic mobility values of modafinil enantiomers at different concentrations of S-β-CD in the BGE. The highest inclusion affinity of the modafinil enantiomers were observed for the S-enantiomer-S-β-CD complex, in agreement with the computational calculations performed previously. Binding constants for each enantiomer-S-β-CD complex at different temperatures, as well as thermodynamic parameters for binding, were calculated. Host-guest binding constants using the double reciprocal fit showed better linearity (r(2)>0.99) at all temperatures studied (15-30°C) and compared with the other two fit methods. The linear van't Hoff (15-30°C) plot obtained indicated that the thermodynamic parameters of complexation were temperature dependent for the enantiomers.
    Matched MeSH terms: Linear Models
  12. Age at menarche of university students in Bangladesh: secular trends and association with adult anthropometric measures and socio-demographic factors
    Hossain MG, Islam S, Aik S, Zaman TK, Lestrel PE
    J Biosoc Sci, 2010 Sep;42(5):677-87.
    PMID: 20529410 DOI: 10.1017/S0021932010000210
    Age at menarche has been shown to be an important indicator for diseases such as breast cancer and ischaemic heart disease. The aim of the present study was to document secular trends in age at menarche and their association with anthropometric measures and socio-demographic factors in university students in Bangladesh. Data were collected from 995 students from Rajshahi University using a stratified sampling technique between July 2004 and May 2005. Trends in age at menarche were examined by linear regression analysis. Multiple regression analysis was used to assess the association of age at menarche with adult anthropometric measures and various socio-demographic factors. The mean and median age of menarche were 13.12+/-1.16 and 13.17 years, respectively, with an increasing tendency among birth-year cohorts from 1979 to 1986. Menarcheal age was negatively associated with BMI (p<0.01), but positively associated with height (p<0.05). Early menarche was especially pronounced among students from urban environments, Muslims and those with better educated mothers. Increasing age at menarche may be explained by improved nutritional status among Bangladeshi populations. Early menarche was associated with residence location at adolescence, religion and mother's education.
    Matched MeSH terms: Linear Models
  13. Fulltext Paraoxonase 1 activity as a predictor of cardiovascular disease in type 2 diabetes
    Poh R, Muniandy S
    Southeast Asian J. Trop. Med. Public Health, 2010 Sep;41(5):1231-46.
    PMID: 21073045
    The role of paraoxonase 1 in cardiovascular disease complications in type 2 diabetes mellitus is not fully understood. We studied paraoxonase activity towards paraoxon in 188 non-diabetic and 140 diabetic subjects using general linear models and univariate analysis. Adjusting for age revealed a reduction in activity towards paraoxon was associated with a significant increase in risk (p = 0.023) for cardiovascular disease complications in diabetic patients. Multivariate analysis of two plasma measures of paraoxonase activity using paraoxon and diazoxon also showed reduced paraoxonase activity towards paraoxon was associated with a significant increase in risk (p = 0.045) for cardiovascular disease complications in diabetic patients. These analyses showed that a reduced paraoxonase activity towards paraoxon was associated with ethnicity. Based on multivariate analysis, subjects of Malay ethnic origin have significantly higher than expected activity (p = 0.008, compared to Indians), towards paraoxon than subjects of Chinese origin who in turn had higher than expected paraoxonase activity (p = 0.028, compared to Indians) Indian subjects.
    Matched MeSH terms: Linear Models
  14. Dynamic supported liquid membrane tip extraction of glyphosate and aminomethylphosphonic acid followed by capillary electrophoresis with contactless conductivity detection
    See HH, Hauser PC, Sanagi MM, Ibrahim WA
    J Chromatogr A, 2010 Sep 10;1217(37):5832-8.
    PMID: 20696433 DOI: 10.1016/j.chroma.2010.07.054
    A dynamic supported liquid membrane tip extraction (SLMTE) procedure for the effective extraction and preconcentration of glyphosate (GLYP) and its metabolite aminomethylphosphonic acid (AMPA) in water has been investigated. The SLMTE procedure was performed in a semi-automated dynamic mode and demonstrated a greater performance against a static extraction. Several important extraction parameters such as donor phase pH, cationic carrier concentration, type of membrane solvent, type of acceptor stripping phase, agitation and extraction time were comprehensively optimized. A solution of Aliquat-336, a cationic carrier, in dihexyl ether was selected as the supported liquid incorporated into the membrane phase. Quantification of GLYP and AMPA was carried out using capillary electrophoresis with contactless conductivity detection. An electrolyte solution consisting of 12 mM histidine (His), 8 mM 2-(N-morpholino)ethanesulfonic acid (MES), 75 microM cetyltrimethylammonium bromide (CTAB), 3% methanol, pH 6.3, was used as running buffer. Under the optimum extraction conditions, the method showed good linearity in the range of 0.01-200 microg/L (GLYP) and 0.1-400 microg/L (AMPA), acceptable reproducibility (RSD 5-7%, n=5), low limits of detection of 0.005 microg/L for GLYP and 0.06 microg/L for AMPA, and satisfactory relative recoveries (90-94%). Due to the low cost, the SLMTE device was disposed after each run which additionally eliminated the possibility of carry-over between runs. The validated method was tested for the analysis of both analytes in spiked tap water and river water with good success.
    Matched MeSH terms: Linear Models
  15. Multi-residue analytical method for human pharmaceuticals and synthetic hormones in river water and sewage effluents by solid-phase extraction and liquid chromatography-tandem mass spectrometry
    Al-Odaini NA, Zakaria MP, Yaziz MI, Surif S
    J Chromatogr A, 2010 Oct 29;1217(44):6791-806.
    PMID: 20851398 DOI: 10.1016/j.chroma.2010.08.033
    Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with 30 min total run time. River water samples (150 mL) and (sewage treatment plant) STP effluents (100 mL) adjusted to pH 2, were loaded into MCX (3 cm(3), 60 mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC-ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281 ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865 ng/L in STP effluent, and 182 ng/L in river water.
    Matched MeSH terms: Linear Models
  16. Fulltext Medicines information provided by pharmaceutical representatives: a comparative study in Australia and Malaysia
    Othman N, Vitry AI, Roughead EE, Ismail SB, Omar K
    BMC Public Health, 2010;10:743.
    PMID: 21118551 DOI: 10.1186/1471-2458-10-743
    BACKGROUND: Pharmaceutical representatives provide medicines information on their promoted products to doctors. However, studies have shown that the quality of this information is often low. No study has assessed the medicines information provided by pharmaceutical representatives to doctors in Malaysia and no recent evidence in Australia is present. We aimed to compare the provision of medicines information by pharmaceutical representatives to doctors in Australia and Malaysia.
    METHODS: Following a pharmaceutical representative's visit, general practitioners in Australia and Malaysia who had agreed to participate, were asked to fill out a questionnaire on the main product and claims discussed during the encounter. The questionnaire focused on provision of product information including indications, adverse effects, precautions, contraindications and the provision of information on the Pharmaceutical Benefit Scheme (PBS) listings and restrictions (in Australia only). Descriptive statistics were produced. Chi-square analysis and clustered linear regression were used to assess differences in Australia and Malaysia.
    RESULTS: Significantly more approved product information sheets were provided in Malaysia (78%) than in Australia (53%) (P < 0.001). In both countries, general practitioners reported that indications (Australia, 90%, Malaysia, 93%) and dosages (Australia, 76%, Malaysia, 82%) were frequently provided by pharmaceutical representatives. Contraindications, precautions, drug interactions and adverse effects were often omitted in the presentations (range 25% - 41%). General practitioners in Australia and Malaysia indicated that in more than 90% of presentations, pharmaceutical representatives partly or fully answered their questions on contraindications, precautions, drug interactions and adverse effects. More general practitioners in Malaysia (85%) than in Australia (60%) reported that pharmaceutical representatives should have mentioned contraindications, precautions for use, drug interaction or adverse effects spontaneously (P < 0.001). In 48% of the Australian presentations, general practitioners reported the pharmaceutical representatives failed to mention information on PBS listings to general practitioners.
    CONCLUSIONS: Information on indications and dosages were usually provided by pharmaceutical representatives in Australia and Malaysia. However, risk and harmful effects of medicines were often missing in their presentations. Effective control of medicines information provided by pharmaceutical representatives is needed.
    Matched MeSH terms: Linear Models
  17. High 5-hydroxymethylfurfural concentrations are found in Malaysian honey samples stored for more than one year
    Khalil MI, Sulaiman SA, Gan SH
    Food Chem Toxicol, 2010 Aug-Sep;48(8-9):2388-92.
    PMID: 20595027 DOI: 10.1016/j.fct.2010.05.076
    5-Hydroxymethylfurfural (HMF) content is an indicator of the purity of honey. High concentrations of HMF in honey indicate overheating, poor storage conditions and old honey. This study investigated the HMF content of nine Malaysian honey samples, as well as the correlation of HMF formation with physicochemical properties of honey. Based on the recommendation by the International Honey Commission, three methods for the determination of HMF were used: (1) high performance liquid chromatography (HPLC), (2) White spectrophotometry and (3) Winkler spectrophotometry methods. HPLC and White spectrophotometric results yielded almost similar values, whereas the Winkler method showed higher readings. The physicochemical properties of honey (pH, free acids, lactones and total acids) showed significant correlation with HMF content and may provide parameters that could be used to make quick assessments of honey quality. The HMF content of fresh Malaysian honey samples stored for 3-6 months (at 2.80-24.87 mg/kg) was within the internationally recommended value (80 mg/kg for tropical honeys), while honey samples stored for longer periods (12-24 months) contained much higher HMF concentrations (128.19-1131.76 mg/kg). Therefore, it is recommended that honey should generally be consumed within one year, regardless of the type.
    Matched MeSH terms: Linear Models
  18. Differences in serum potassium concentrations between Chinese, Indians and Malays
    Hawkins RC
    Clin Chem Lab Med, 2010;48(1):105-8.
    PMID: 19929751 DOI: 10.1515/CCLM.2010.010
    It has been suggested that potassium concentrations may vary between different geographical regions, possibly reflecting ethnic differences in potassium status. This study compared the serum potassium concentrations of three Asian ethnicities in a single geographical location.
    Matched MeSH terms: Linear Models
  19. Fulltext The PCA and LDA analysis on the differential expression of proteins in breast cancer
    Liang S, Singh M, Dharmaraj S, Gam LH
    Dis Markers, 2010;29(5):231-42.
    PMID: 21206008 DOI: 10.3233/DMA-2010-0753
    Breast cancer is a leading cause of mortality in women. In Malaysia, it is the most common cancer to affect women. The most common form of breast cancer is infiltrating ductal carcinoma (IDC). A proteomic approach was undertaken to identify protein profile changes between cancerous and normal breast tissues from 18 patients. Two protein extracts; aqueous soluble and membrane associated protein extracts were studied. Thirty four differentially expressed proteins were identified. The intensities of the proteins were used as variables in PCA and reduced data of six principal components (PC) were subjected to LDA in order to evaluate the potential of these proteins as collective biomarkers for breast cancer. The protein intensities of SEC13-like 1 (isoform b) and calreticulin contributed the most to the first PC while the protein intensities of fibrinogen beta chain precursor and ATP synthase D chain contributed the most to the second PC. Transthyretin precursor and apolipoprotein A-1 precursor contributed the most to the third PC. The results of LDA indicated good classification of samples into normal and cancerous types when the first 6 PCs were used as the variables. The percentage of correct classification was 91.7% for the originally grouped tissue samples and 88.9% for cross-validated samples.
    Matched MeSH terms: Linear Models
  20. Effect of steam blanching on lycopene and total phenolics in pink guava puree industry by-products
    Kong, K.W., Emmy, H.K.I., Azizah, O., Amin, I., Tan, C.P.
    International Food Research Journal, 2010;17(2):461-468.
    MyJurnal
    Lycopene and total phenolics of pink guava puree industry by-products (refiner, siever and decanter)
    were evaluated after steam blanching at selected temperatures and times. Lycopene content was in the order of decanter > siever > refiner (7.3, 6.3 and 1.5 mg/100 g, respectively), and the content of total phenolics was in the order of refiner > siever > decanter (4434.1, 2881.3 and 1529.3 mg GAE/100 g, respectively). Regression coefficients for temperatures (x1) and times (x2) from multiple linear regression models of siever and decanter showed significant (p
    Matched MeSH terms: Linear Models
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