Displaying publications 1 - 20 of 390 in total

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  1. Jong WL, Ung NM, Vannyat A, Jamalludin Z, Rosenfeld A, Wong JH
    Phys Med, 2017 Jan;33:127-135.
    PMID: 28089106 DOI: 10.1016/j.ejmp.2016.12.020
    Dosimetry in small radiation field is challenging and complicated because of dose volume averaging and beam perturbations in a detector. We evaluated the suitability of the "Edge-on" MOSkin (MOSFET) detector in small radiation field measurement. We also tested the feasibility for dosimetric verification in stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). "Edge-on" MOSkin detector was calibrated and the reproducibility and linearity were determined. Lateral dose profiles and output factors were measured using the "Edge-on" MOSkin detector, ionization chamber, SRS diode and EBT2 film. Dosimetric verification was carried out on two SRS and five SRT plans. In dose profile measurements, the "Edge-on" MOSkin measurements concurred with EBT2 film measurements. It showed full width at half maximum of the dose profile with average difference of 0.11mm and penumbral width with difference of ±0.2mm for all SRS cones as compared to EBT2 film measurement. For output factor measurements, a 1.1% difference was observed between the "Edge-on" MOSkin detector and EBT2 film for 4mm SRS cone. The "Edge-on" MOSkin detector provided reproducible measurements for dose verification in real-time. The measured doses concurred with the calculated dose for SRS (within 1%) and SRT (within 3%). A set of output correction factors for the "Edge-on" MOSkin detector for small radiation fields were derived from EBT2 film measurement and presented. This study showed that the "Edge-on" MOSkin detector is a suitable tool for dose verification in small radiation field.
    Matched MeSH terms: Linear Models
  2. Hafidh RR, Hussein SZ, MalAllah MQ, Abdulamir AS, Abu Bakar F
    Curr Cancer Drug Targets, 2018;18(8):807-815.
    PMID: 29141549 DOI: 10.2174/1568009617666171114144236
    BACKGROUND: Citrus bioactive compounds, as active anticancer agents, have been under focus by several studies worldwide. However, the underlying genes responsible for the anticancer potential have not been sufficiently highlighted.

    OBJECTIVES: The current study investigated the gene expression profile of hepatocellular carcinoma, HepG2, cells after treatment with Limonene.

    METHODS: The concentration that killed 50% of HepG2 cells was used to elucidate the genetic mechanisms of limonene anticancer activity. The apoptotic induction was detected by flow cytometry and confocal fluorescence microscope. Two of the pro-apoptotic events, caspase-3 activation and phosphatidylserine translocation were manifested by confocal fluorescence microscopy. Highthroughput real-time PCR was used to profile 1023 cancer-related genes in 16 different gene families related to the cancer development.

    RESULTS: In comparison to untreated cells, limonene increased the percentage of apoptotic cells up to 89.61%, by flow cytometry, and 48.2% by fluorescence microscopy. There was a significant limonene- driven differential gene expression of HepG2 cells in 15 different gene families. Limonene was shown to significantly (>2log) up-regulate and down-regulate 14 and 59 genes, respectively. The affected gene families, from the most to the least affected, were apoptosis induction, signal transduction, cancer genes augmentation, alteration in kinases expression, inflammation, DNA damage repair, and cell cycle proteins.

    CONCLUSION: The current study reveals that limonene could be a promising, cheap, and effective anticancer compound. The broad spectrum of limonene anticancer activity is interesting for anticancer drug development. Further research is needed to confirm the current findings and to examine the anticancer potential of limonene along with underlying mechanisms on different cell lines.

    Matched MeSH terms: Linear Models
  3. Wali HA, Mazlan R, Kei J
    Ear Hear, 2019 2 27;40(5):1233-1241.
    PMID: 30807541 DOI: 10.1097/AUD.0000000000000707
    OBJECTIVES: Wideband absorbance (WBA) is an emerging technology to evaluate the conductive pathway (outer and middle ear) in young infants. While a wealth of research has been devoted to measuring WBA at ambient pressure, few studies have investigated the use of pressurized WBA with this population. The purpose of this study was to investigate the effect of age on WBA measured under pressurized conditions in healthy infants from 0 to 6 months of age.

    DESIGN: Forty-four full-term healthy neonates (17 males and 27 females) participated in a longitudinal study. The neonates were assessed at 1-month intervals from 0 to 6 months of age using high-frequency tympanometry, acoustic stapedial reflex, distortion product otoacoustic emissions, and pressurized WBA. The values of WBA at tympanometric peak pressure (TPP) and 0 daPa across the frequencies from 0.25 to 8 kHz were analyzed as a function of age.

    RESULTS: A linear mixed model analysis, applied to the data, revealed significantly different WBA patterns among the age groups. In general, WBA measured at TPP and 0 daPa decreased at low frequencies (<0.4 kHz) and increased at high frequencies (2 to 5and 8 kHz) with age. Specifically, WBA measured at TPP and 0 daPa in 3- to 6-month-olds was significantly different from that of 0- to 2-month-olds at low (0.25 to 0.31 kHz) and high (2 to 5 and 8 kHz) frequencies. However, there were no significant differences between WBA measured at TPP and 0 daPa for infants from 3 to 6 months of age.

    CONCLUSIONS: The present study provided clear evidence of maturation of the outer and middle ear system in healthy infants from birth to 6 months. Therefore, age-specific normative data of pressurized WBA are warranted.

    Matched MeSH terms: Linear Models
  4. Mohammadi A, Karimzadeh S, Jalal SJ, Kamran KV, Shahabi H, Homayouni S, et al.
    Sensors (Basel), 2020 Dec 16;20(24).
    PMID: 33339435 DOI: 10.3390/s20247214
    Digital elevation model (DEM) plays a vital role in hydrological modelling and environmental studies. Many essential layers can be extracted from this land surface information, including slope, aspect, rivers, and curvature. Therefore, DEM quality and accuracy will affect the extracted features and the whole process of modeling. Despite freely available DEMs from various sources, many researchers generate this information for their areas from various observations. Sentinal-1 synthetic aperture radar (SAR) images are among the best Earth observations for DEM generation thanks to their availabilities, high-resolution, and C-band sensitivity to surface structure. This paper presents a comparative study, from a hydrological point of view, on the quality and reliability of the DEMs generated from Sentinel-1 data and DEMs from other sources such as AIRSAR, ALOS-PALSAR, TanDEM-X, and SRTM. To this end, pair of Sentinel-1 data were acquired and processed using the SAR interferometry technique to produce a DEM for two different study areas of a part of the Cameron Highlands, Pahang, Malaysia, a part of Sanandaj, Iran. Based on the estimated linear regression and standard errors, generating DEM from Sentinel-1 did not yield promising results. The river streams for all DEMs were extracted using geospatial analysis tool in a geographic information system (GIS) environment. The results indicated that because of the higher spatial resolution (compared to SRTM and TanDEM-X), more stream orders were delineated from AIRSAR and Sentinel-1 DEMs. Due to the shorter perpendicular baseline, the phase decorrelation in the created DEM resulted in a lot of noise. At the same time, results from ground control points (GCPs) showed that the created DEM from Sentinel-1 is not promising. Therefore, other DEMs' performance, such as 90-meters' TanDEM-X and 30-meters' SRTM, are better than Sentinel-1 DEM (with a better spatial resolution).
    Matched MeSH terms: Linear Models
  5. Kwan MK, Lee SY, Ch'ng PY, Chung WH, Chiu CK, Chan CYW
    Spine (Phila Pa 1976), 2020 Jun 15;45(12):E694-E703.
    PMID: 32032325 DOI: 10.1097/BRS.0000000000003407
    STUDY DESIGN: Retrospective study.

    OBJECTIVE: To investigate the relationship between a +ve postoperative Upper Instrumented Vertebra (UIV) (≥0°) tilt angle and the risk of medial shoulder/neck and lateral shoulder imbalance among Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) patients following Posterior Spinal Fusion.

    SUMMARY OF BACKGROUND DATA: Current UIV selection strategy has poor correlation with postoperative shoulder balance. The relationship between a +ve postoperative UIV tilt angle and the risk of postoperative shoulder and neck imbalance was unknown.

    METHODS: One hundred thirty-six Lenke 1 and 2 AIS patients with minimum 2 years follow-up were recruited. For medial shoulder and neck balance, patients were categorized into positive (+ve) imbalance (≥+4°), balanced, or negative (-ve) imbalance (≤-4°) groups based on T1 tilt angle/Cervical Axis measurement. For lateral shoulder balance, patients were classified into +ve imbalance (≥+3°) balanced, and -ve imbalance (≤-3°) groups based on Clavicle Angle (Cla-A) measurement. Linear regression analysis identified the predictive factors for shoulder/neck imbalance. Logistic regression analysis calculated the odds ratio of shoulder/neck imbalance for patients with +ve postoperative UIV tilt angle.

    RESULTS: Postoperative UIV tilt angle and preoperative T1 tilt angle were predictive of +ve medial shoulder imbalance. Postoperative UIV tilt angle and postoperative PT correction were predictive of +ve neck imbalance. Approximately 51.6% of patients with +ve medial shoulder imbalance had +ve postoperative UIV tilt angle. Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance and 3.3 times increased odds of developing +ve neck imbalance. Postoperative UIV tilt angle did not predict lateral shoulder imbalance.

    CONCLUSION: Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance (T1 tilt angle ≥+4°) and 3.3 times increased odds of developing +ve neck imbalance (cervical axis ≥+4°).

    LEVEL OF EVIDENCE: 4.

    Matched MeSH terms: Linear Models
  6. Hamdi OA, Anouar el H, Shilpi JA, Trabolsy ZB, Zain SB, Zakaria NS, et al.
    Int J Mol Sci, 2015 Apr 27;16(5):9450-68.
    PMID: 25923077 DOI: 10.3390/ijms16059450
    A series of 21 compounds isolated from Curcuma zedoaria was subjected to cytotoxicity test against MCF7; Ca Ski; PC3 and HT-29 cancer cell lines; and a normal HUVEC cell line. To rationalize the structure-activity relationships of the isolated compounds; a set of electronic; steric and hydrophobic descriptors were calculated using density functional theory (DFT) method. Statistical analyses were carried out using simple and multiple linear regressions (SLR; MLR); principal component analysis (PCA); and hierarchical cluster analysis (HCA). SLR analyses showed that the cytotoxicity of the isolated compounds against a given cell line depend on certain descriptors; and the corresponding correlation coefficients (R2) vary from 0%-55%. MLR results revealed that the best models can be achieved with a limited number of specific descriptors applicable for compounds having a similar basic skeleton. Based on PCA; HCA and MLR analyses; active compounds were classified into subgroups; which was in agreement with the cell based cytotoxicity assay.
    Matched MeSH terms: Linear Models
  7. Zakaria A, Shakaff AY, Masnan MJ, Ahmad MN, Adom AH, Jaafar MN, et al.
    Sensors (Basel), 2011;11(8):7799-822.
    PMID: 22164046 DOI: 10.3390/s110807799
    The major compounds in honey are carbohydrates such as monosaccharides and disaccharides. The same compounds are found in cane-sugar concentrates. Unfortunately when sugar concentrate is added to honey, laboratory assessments are found to be ineffective in detecting this adulteration. Unlike tracing heavy metals in honey, sugar adulterated honey is much trickier and harder to detect, and traditionally it has been very challenging to come up with a suitable method to prove the presence of adulterants in honey products. This paper proposes a combination of array sensing and multi-modality sensor fusion that can effectively discriminate the samples not only based on the compounds present in the sample but also mimic the way humans perceive flavours and aromas. Conversely, analytical instruments are based on chemical separations which may alter the properties of the volatiles or flavours of a particular honey. The present work is focused on classifying 18 samples of different honeys, sugar syrups and adulterated samples using data fusion of electronic nose (e-nose) and electronic tongue (e-tongue) measurements. Each group of samples was evaluated separately by the e-nose and e-tongue. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were able to separately discriminate monofloral honey from sugar syrup, and polyfloral honey from sugar and adulterated samples using the e-nose and e-tongue. The e-nose was observed to give better separation compared to e-tongue assessment, particularly when LDA was applied. However, when all samples were combined in one classification analysis, neither PCA nor LDA were able to discriminate between honeys of different floral origins, sugar syrup and adulterated samples. By applying a sensor fusion technique, the classification for the 18 different samples was improved. Significant improvement was observed using PCA, while LDA not only improved the discrimination but also gave better classification. An improvement in performance was also observed using a Probabilistic Neural Network classifier when the e-nose and e-tongue data were fused.
    Matched MeSH terms: Linear Models
  8. Skau JK, Nordin AB, Cheah JC, Ali R, Zainal R, Aris T, et al.
    Trials, 2016;17(1):215.
    PMID: 27117703 DOI: 10.1186/s13063-016-1345-x
    Over the past two decades, the population of Malaysia has grown rapidly and the prevalence of diabetes mellitus in Malaysia has dramatically increased, along with the frequency of obesity, hyperlipidaemia and hypertension. Early-life influences play an important role in the development of non-communicable diseases. Indeed, maternal lifestyle and conditions such as gestational diabetes mellitus or obesity can affect the risk of diabetes in the next generation. Lifestyle changes can help to prevent the development of type 2 diabetes mellitus. This is a protocol for an unblinded, community-based, randomised controlled trial in two arms to evaluate the efficacy of a complex behavioural change intervention, combining motivational interviewing provided by a community health promoter and access to a habit formation mobile application, among young Malaysian women and their spouses prior to pregnancy.
    Matched MeSH terms: Linear Models
  9. Abdul Ghapor Hussin, Norli Anida Abdullah, Ibrahim Mohamed
    This paper gives a comprehensive discussion on complex regression model by extending the idea of regression model to circular variables. Various aspect have been considered such as the biasness of parameters, error assumptions and model checking. The advantage of this approach is that it allows the use of usual technique available in ordinary linear regression for the regression of circular variables. The quality of the estimates and the feasibility of the approach were illustrated via simulation. The model was then applied to the wave direction data.
    Matched MeSH terms: Linear Models
  10. Ang SH, Thevarajah TM, Woi PM, Alias YB, Khor SM
    J Chromatogr B Analyt Technol Biomed Life Sci, 2016 Mar 15;1015-1016:157-165.
    PMID: 26927875 DOI: 10.1016/j.jchromb.2016.01.059
    An immunosensor that operates based on the principles of lateral flow was developed for direct detection of hemoglobin A1c (HbA1c) in whole blood. We utilized colloidal gold-functionalized antibodies to transduce the specific signal generated when sandwich immuno-complexes were formed on the strip in the presence of HbA1c. The number and intensity of the test lines on the strips indicate normal, under control, and elevated levels of HbA1c. In addition, a linear relationship between HbA1c levels and immunosensor signal intensity was confirmed, with a dynamic range of 4-14% (20-130 mmol mol(-1)) HbA1c. Using this linear relationship, we determined the HbA1c levels in blood as a function of the signal intensity on the strips. Measurements were validated using the Bio-Rad Variant II HPLC and DCA Vantage tests. Moreover, the immunosensor was verified to be highly selective for detection of HbA1c against HbA0, glycated species of HbA0, and HbA2. The limit of detection was found to be 42.5 μg mL(-1) (1.35 mmol mol(-1)) HbA1c, which is reasonably sensitive compared to the values reported for microarray immunoassays. The shelf life of the immunosensor was estimated to be 1.4 months when stored at ambient temperature, indicating that the immunoassay is stable. Thus, the lateral flow immunosensor developed here was shown to be capable of performing selective, accurate, rapid, and stable detection of HbA1c in human blood samples.
    Matched MeSH terms: Linear Models
  11. Muazu Musa R, P P Abdul Majeed A, Taha Z, Chang SW, Ab Nasir AF, Abdullah MR
    PLoS One, 2019;14(1):e0209638.
    PMID: 30605456 DOI: 10.1371/journal.pone.0209638
    k-nearest neighbour (k-NN) has been shown to be an effective learning algorithm for classification and prediction. However, the application of k-NN for prediction and classification in specific sport is still in its infancy. The present study classified and predicted high and low potential archers from a set of physical fitness variables trained on a variation of k-NN algorithms and logistic regression. 50 youth archers with the mean age and standard deviation of (17.0 ± 0.56) years drawn from various archery programmes completed a one end archery shooting score test. Standard fitness measurements of the handgrip, vertical jump, standing broad jump, static balance, upper muscle strength and the core muscle strength were conducted. Multiple linear regression was utilised to ascertain the significant variables that affect the shooting score. It was demonstrated from the analysis that core muscle strength and vertical jump were statistically significant. Hierarchical agglomerative cluster analysis (HACA) was used to cluster the archers based on the significant variables identified. k-NN model variations, i.e., fine, medium, coarse, cosine, cubic and weighted functions as well as logistic regression, were trained based on the significant performance variables. The HACA clustered the archers into high potential archers (HPA) and low potential archers (LPA). The weighted k-NN outperformed all the tested models at itdemonstrated reasonably good classification on the evaluated indicators with an accuracy of 82.5 ± 4.75% for the prediction of the HPA and the LPA. Moreover, the performance of the classifiers was further investigated against fresh data, which also indicates the efficacy of the weighted k-NN model. These findings could be valuable to coaches and sports managers to recognise high potential archers from a combination of the selected few physical fitness performance indicators identified which would subsequently save cost, time and energy for a talent identification programme.
    Matched MeSH terms: Linear Models
  12. Rohawi NS, Ramasamy K, Agatonovic-Kustrin S, Lim SM
    PMID: 29894935 DOI: 10.1016/j.jchromb.2018.06.009
    A quantitative assay using high-performance thin-layer chromatography (HPTLC) was developed to investigate bile salt hydrolase (BSH) activity in Pediococcus pentosaceus LAB6 and Lactobacillus plantarum LAB12 probiotic bacteria isolated from Malaysian fermented food. Lactic acid bacteria (LAB) were cultured in de Man Rogosa and Sharpe (MRS) broth containing 1 mmol/L of sodium-based glyco- and tauro-conjugated bile salts for 24 h. The cultures were centrifuged and the resultant cell free supernatant was subjected to chromatographic separation on a HPTLC plate. Conjugated bile salts were quantified by densitometric scans at 550 nm and results were compared to digital image analysis of chromatographic plates after derivatisation with anisaldehyde/sulfuric acid. Standard curves for bile salts determination with both methods show good linearity with high coefficient of determination (R2) between 0.97 and 0.99. Method validation indicates good sensitivity with low relative standard deviation (RSD) (<10%), low limits of detection (LOD) of 0.4 versus 0.2 μg and limit of quantification (LOQ) of 1.4 versus 0.7 μg, for densitometric vs digital image analysis method, respectively. The bile salt hydrolase activity was found to be higher against glyco- than tauro-conjugated bile salts (LAB6; 100% vs >38%: LAB12; 100% vs >75%). The present findings strongly show that quantitative analysis via digitally-enhanced HPTLC offers a rapid quantitative analysis for deconjugation of bile salts by probiotics.
    Matched MeSH terms: Linear Models
  13. Wan Muhamad Amir W. Ahmad, Mohamad Arif Awang Nawi, Mustafa Mamat
    MyJurnal
    This paper proposes the use of bootstrap, robust and fuzzy multiple linear regressions method in
    handling general insurance in order to get improved results. The main objective of bootstrapping is to
    estimate the distribution of an estimator or test statistic by resampling one's data or a model estimated
    from the data under conditions that hold in a wide variety of econometric applications. In addition,
    bootstrap also provides approximations to distributions of statistics, coverage probabilities of confidence
    intervals, and rejection probabilities of hypothesis tests that produce accurate results. In this paper, we
    emphasize the combining and modelling using bootstrapping, robust and fuzzy regression methodology.
    The results show that alternative methods produce better results than multiple linear regressions (MLR)
    model.
    Matched MeSH terms: Linear Models
  14. Ataie-Jafari A, Loke SC, Rahmat AB, Larijani B, Abbasi F, Leow MK, et al.
    Clin Nutr, 2013 Dec;32(6):911-7.
    PMID: 23395257 DOI: 10.1016/j.clnu.2013.01.012
    This participant-blinded parallel-group randomized placebo-controlled study demonstrated that alfacalcidol (vitamin D analogue) preserves beta cell function in newly diagnosed type 1 diabetes (T1DM) in children.
    Matched MeSH terms: Linear Models
  15. Gumel AB, Kubota K, Twizell EH
    Math Biosci, 1998 Aug 15;152(1):87-103.
    PMID: 9727298
    A sequential algorithm is developed for the non-linear dual-sorption model developed by Chandrasekaran et al. [1,2] which monitors pharmacokinetic profiles in percutaneous drug absorption. In the experimental study of percutaneous absorption, it is often observed that the lag-time decreases with the increase in the donor concentration when two or more donor concentrations of the same compound are used. The dual-sorption model has sometimes been employed to explain such experimental results. In this paper, it is shown that another feature observed after vehicle removal may also characterize the dual-sorption model. Soon after vehicle removal, the plots of the drug flux versus time become straight lines on a semilogarithmic scale as in the linear model, but the half-life is prolonged thereafter when the dual-sorption model prevails. The initial half-life after vehicle removal with a low donor concentration is longer than that with a higher donor concentration. These features, if observed in experiments, may be used as evidence to confirm that the dual-sorption model gives an explanation to the non-linear kinetic behaviour of a permeant.
    Matched MeSH terms: Linear Models
  16. Mohd Zukri, I., Noor Hassim, I.
    MyJurnal
    Introduction: The effect of stress among correctional officers at the workplace can contribute to various health problems and this also affect their work performance and motivation.
    Methodology: Study was done at a prison located at the rural district in Kedah. The study was conducted by using randomized stratified sampling method. A total of 418 self administrated questionnaires were distributed. These questionnaires included socio demographic factor, family and marriage factor, Personal Stress Inventory (using Stress Symptom Scale with 52 items), work related stressors (Job Stress Survey) and Brief COPE (Coping Orientation for Problems Experienced with 28 items).
    Result: Response rate was 90.9%. Stress prevalence for correctional officers was 45.8%. Socio demographic factors which have significant relation with stress status were marital status, promotion factor, age, monthly salary, duration of service and number of children (p< 0.05). Family and marriage factor which have significant relation with stress status among married officer were pressure from relatives, clean up house, sexual frustration, conflict with spouse, conflict with children, conflict due to household work and no babysitter (p< 0.05).
    Discussion: The study showed that work related stressors that have influence with stress were excessive workload, working after work hours, not enough staff, disgraced words from fellow workers, competition in carrier development and excessive work stress (p< 0.05). Multiple linear regression model was done in this study and revealed factors that explained 52% of variation in stress score distributions were behavioural disengagement, no babysitter, denial, conflict with children, replace other worker’s duty, not enough time with family, competition in carrier development, venting of emotion, positive reframing and emotional support. Coping strategies that have significant effect in reducing stress symptoms are positive reframing and emotional support.
    Conclusion: Stress management programs should be implemented and emphasizing on specific stressors and coping mechanism are important to reduce the risk of occupational stress among correctional officers.
    Matched MeSH terms: Linear Models
  17. Loke, S.T.
    MyJurnal
    The aims of the study were to investigate patient satisfaction and perceived psychosocial benefit from orthodontic treatment and to relate them to factors ajfecting treatment duration and treatment standards. A total of 130 patients (mean age I5 years) who had just completed full fixed appliance therapy (removable appliance) filled questionnaires. There was high proportion of satisfaction with dentofacial appearance (98.5 %), alignment of teeth (100 %), improved mastication (99.2%) and cleaning of teeth (98.5%). About 89.2% would recommend orthodontic treatment to their friends. All surveyed were satisfied with the services provided by the orthodontic staff and kw patients were dissatisfied with the length of each appointment (3.] %), number of appointments (l.5%) and total treatment time (5.4%). The main dissatisfaction appeared to be the long waiting time to be treated during their appointments (10%}. The mean duration of treatment to complete two-arch fixed appliance was I 7.6 months (S.D. 6.8 months) and 89.2% of cases were completed within 24 months. Treatment duration was also associated with pre-treatment ovemet (r=0.23 5), ovetjet d%rence_h·om pre-treatment to post-treatment 0·=0.204} and number of extractions (r=0.305}. Multmle linear regression anahtsis of duration of treatment with these factors accounted for about 7.8% ofthe variability.
    Study site: Dental clinic, Kota Kinabalu, Sabah, Malaysia
    Matched MeSH terms: Linear Models
  18. Jirjees F, Soliman K, Wang Y, Sonawane R, Sheshala R, Jones D, et al.
    J Pharm Biomed Anal, 2019 Sep 10;174:145-150.
    PMID: 31167158 DOI: 10.1016/j.jpba.2019.05.038
    Bevacizumab is a full-length human monoclonal antibody used to treat various neovascular diseases such as wet age-related macular degeneration (AMD), diabetic eye disease and other problems of the retina. Monthly intravitreal injections of bevacizumab (Avastin®) are effective in the treatment of wet AMD. However, there is a growing demand in the development of sustained release ophthalmic formulations. Therefore, this study aims, for the first time, to develop a rapid, simple, and sensitive method using size exclusion chromatography coupled with fluorescence detection for routine quantification of bevacizumab in ophthalmic formulations and during in vitro release studies. The selected chromatographic conditions included an aqueous mobile phase composed of 35 mM sodium phosphate buffer and 300 mM sodium chloride (pH 6.8), a flow rate of 0.5 mL/min, and the fluorescence detector was operated at excitation and emission wavelengths of 280 and 340 nm, respectively. The peak area-concentration relationship maintained its linearity over concentration range of 0.1-20 μg/mL (R2 = 0.9993), and the quantitation limit was 100 ng/mL. The method was validated for specificity, accuracy, precision, and robustness. The developed method had a run time of 6 min at temperature 25 °C, making it a unique validated method for rapid and cost-effective quantification of bevacizumab.
    Matched MeSH terms: Linear Models
  19. Akinpelu AA, Chowdhury ZZ, Shibly SM, Faisal ANM, Badruddin IA, Rahman MM, et al.
    Int J Mol Sci, 2021 Feb 19;22(4).
    PMID: 33669883 DOI: 10.3390/ijms22042090
    This study deals with the preparation of activated carbon (CDSP) from date seed powder (DSP) by chemical activation to eliminate polyaromatic hydrocarbon-PAHs (naphthalene-C10H8) from synthetic wastewater. The chemical activation process was carried out using a weak Lewis acid of zinc acetate dihydrate salt (Zn(CH3CO2)2·2H2O). The equilibrium isotherm and kinetics analysis was carried out using DSP and CDSP samples, and their performances were compared for the removal of a volatile organic compound-naphthalene (C10H8)-from synthetic aqueous effluents or wastewater. The equilibrium isotherm data was analyzed using the linear regression model of the Langmuir, Freundlich and Temkin equations. The R2 values for the Langmuir isotherm were 0.93 and 0.99 for naphthalene (C10H8) adsorption using DSP and CDSP, respectively. CDSP showed a higher equilibrium sorption capacity (qe) of 379.64 µg/g. DSP had an equilibrium sorption capacity of 369.06 µg/g for C10H8. The rate of reaction was estimated for C10H8 adsorption using a pseudo-first order, pseudo-second order and Elovich kinetic equation. The reaction mechanism for both the sorbents (CDSP and DSP) was studied using the intraparticle diffusion model. The equilibrium data was well-fitted with the pseudo-second order kinetics model showing the chemisorption nature of the equilibrium system. CDSP showed a higher sorption performance than DSP due to its higher BET surface area and carbon content. Physiochemical characterizations of the DSP and CDSP samples were carried out using the BET surface area analysis, Fourier-scanning microscopic analysis (FSEM), energy-dispersive X-ray (EDX) analysis and Fourier-transform spectroscopic analysis (FTIR). A thermogravimetric and ultimate analysis was also carried out to determine the carbon content in both the sorbents (DSP and CDSP) here. This study confirms the potential of DSP and CDSP to remove C10H8 from lab-scale synthetic wastewater.
    Matched MeSH terms: Linear Models
  20. Altowayti WAH, Othman N, Al-Gheethi A, Dzahir NHBM, Asharuddin SM, Alshalif AF, et al.
    Molecules, 2021 Oct 13;26(20).
    PMID: 34684757 DOI: 10.3390/molecules26206176
    Sustainable wastewater treatment is one of the biggest issues of the 21st century. Metals such as Zn2+ have been released into the environment due to rapid industrial development. In this study, dried watermelon rind (D-WMR) is used as a low-cost adsorption material to assess natural adsorbents' ability to remove Zn2+ from synthetic wastewater. D-WMR was characterized using scanning electron microscope (SEM) and X-ray fluorescence (XRF). According to the results of the analysis, the D-WMR has two colours, white and black, and a significant concentration of mesoporous silica (83.70%). Moreover, after three hours of contact time in a synthetic solution with 400 mg/L Zn2+ concentration at pH 8 and 30 to 40 °C, the highest adsorption capacity of Zn2+ onto 1.5 g D-WMR adsorbent dose with 150 μm particle size was 25 mg/g. The experimental equilibrium data of Zn2+ onto D-WMR was utilized to compare nonlinear and linear isotherm and kinetics models for parameter determination. The best models for fitting equilibrium data were nonlinear Langmuir and pseudo-second models with lower error functions. Consequently, the potential use of D-WMR as a natural adsorbent for Zn2+ removal was highlighted, and error analysis indicated that nonlinear models best explain the adsorption data.
    Matched MeSH terms: Linear Models
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