Displaying publications 1 - 20 of 57 in total

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  1. An insight into industrial accidents involving the hand
    Abdullah S, Jaafar JM, Das S, Sapuan J
    Clin Ter, 2009;160(6):427-33.
    PMID: 20198282
    BACKGROUND: Industrial hand injuries are a common occurrence and contributes to a large segment of workers' morbidity. The main aim of this study was to look into the day pattern, types and location of upper limbs injures, identify the types of machines involved and highlight the treatment received.
    MATERIALS AND METHODS: The present study was performed on 57 industrial workers admitted and treated by the Orthopaedic team of Universiti Kebangsaan Malaysia Medical Centre (UKMMC) for acute injuries sustained whilst working.
    RESULTS: The majority of the workers were male (93%). The commonest age group involved was between 25-35 years (48%). The right hand was injured more then the left with majority of injuries involving the fingers. Interestingly, we also observed that injuries occurred more on Saturdays. Laceration was the most common injury followed by fractures and crush injuries. Treatment depends on the type and severity of injuries. For most lacerated wounds, treatment was debridement, primary suturing and antibiotic therapy. Injuries on Saturdays indicated that workers needed a longer time break especially during weekends after a long hectic week.
    CONCLUSIONS: Injuries sustained by workers may be prevented by proper working techniques and conditions together with wearing of protective gadgets.

    Study site: Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM)
  2. Fulltext Thermal Stability and Water Content Study of Void-Free Electrospun SPEEK/Cloisite Membrane for Direct Methanol Fuel Cell Application
    Awang N, Jaafar J, Ismail AF
    Polymers (Basel), 2018 Feb 15;10(2).
    PMID: 30966230 DOI: 10.3390/polym10020194
    Void-free electrospun SPEEK/Cloisite15A® densed (SP/e-spunCL) membranes are prepared. Different loadings of Cloisite15A® (0.10, 0.15, 0.20, 0.25 and 0.30 wt %) are incorporated into electrospun fibers. The physico-chemical characteristics (methanol permeability, water uptake and proton conductivity) of the membranes are observed. Thermal stability of all membranes is observed using Thermal Gravimetry Analysis (TGA). The thrree stages of degradation range between 163.1 and 613.1 °C. Differential Scanning Calorimetry (DSC) is used to study the wettability of the membranes. SP/e-spunCL15 shows the lowest freezing bound water of 15.27%, which contributed to the lowest methanol permeability. The non-freezing bound water that proportionally increased with proton conductivity of SP/e-spunCL15 membrane is the highest, 10.60%. It is suggested that the electrospinning as the fabricating method has successfully exfoliated the Cloisite in the membrane surface structure, contributing to the decrease of methanol permeability, while the retained water has led to the enhancement of proton conductivity. This new fabrication method of SP/e-spunCL membrane is said to be a desirable polymer electrolyte membrane for future application in direct methanol fuel cell field.
  3. Distance vision, near vision and quality of life between preferred emmetropia and residual myopia in monofocal intraocular lens implantation- A Comparative study
    Jaafar J, Siti-Khadijah AR, Shaharudin B, Azhany Y
    Med J Malaysia, 2021 05;76(3):340-345.
    PMID: 34031332
    INTRODUCTION: This study was done to evaluate the visual acuity and quality of life in predicted emmetropia (EM) and predicted residual myopia (RM) patients following phacoemulsification with monofocal intraocular lens implantation.

    MATERIALS AND METHODS: This prospective comparative study was conducted in the ophthalmology clinic of the Universiti Sains Malaysia Hospital, Kelantan, Malaysia. Overall, 139 patients with senile cataract were randomised into EM and RM groups. At three months post-operatively, patients were assessed for distance and near vision, as well as quality of life using a modified VF-14 questionnaire.

    RESULTS: Thirty-six patients (64.3%) in the EM group and 30 patients (52.6%) in the RM group (p = 0.209) showed good distance vision (LogMAR 0.3 or better). Fifty patients (87.7%) in the RM group and 27 patients (48.2%) in the EM group gained significantly higher satisfactory near vision (p < 0.05). The quality of life in both groups was good, with a mean modified VF-14 score of 94.5 (SD 2.68) for the EM group and 95.1 (SD 3.19) for the RM group (p = 0.286). Female patients scored significantly higher than males for total activities (p = 0.010) and distance vision-related activities (p = 0.001). The RM group had significantly better patient satisfaction for near vision-related activities compared to the EM group (p = 0.001). In particular, the item 'reading small print' was significantly better in the RM group (p = 0.003).

    CONCLUSION: Patients in the predicted RM group gained more satisfactory near vision than patients in the EM group, with significantly better quality of life for near vision activities.

  4. Fulltext Bilateral atypical optic neuritis associated with tuberculosis in an immunocompromised patient
    Jaafar J, Hitam WH, Noor RA
    Asian Pac J Trop Biomed, 2012 Jul;2(7):586-8.
    PMID: 23569976 DOI: 10.1016/S2221-1691(12)60102-6
    A 27 year-old lady, presented with sudden loss of vision in the right eye for a week. It was followed by poor vision in the left eye after 3 days. It involved the whole entire visual field and was associated with pain on eye movement. She was diagnosed to have miliary tuberculosis and retroviral disease 4 months ago. She was started on anti-TB since then but defaulted highly active anti-retroviral therapy (HAART). On examination, her visual acuity was no perception of light in the right eye and 6/120 (pinhole 3/60) in the left eye. Anterior segment in both eyes was unremarkable. Funduscopy showed bilateral optic disc swelling with presence of multiple foci of choroiditis in the peripheral retina. The vitreous and retinal vessels were normal. Chest radiography was normal. CT scan of orbit and brain revealed bilateral enhancement of the optic nerve sheath that suggest the diagnosis of bilateral atypical optic neuritis. This patient was managed with infectious disease team. She was started on HAART and anti-TB treatment was continued. She completed anti-TB treatment after 9 months without any serious side effects. During follow up the visual acuity in both eyes was not improved. However, funduscopy showed resolving of disc swelling and choroiditis following treatment.
  5. Social skills, friendship and happiness: a cross-cultural investigation
    Demir M, Jaafar J, Bilyk N, Ariff MR
    J Soc Psychol, 2012 May-Jun;152(3):379-85.
    PMID: 22558831 DOI: 10.1080/00224545.2011.591451
    The present study investigated the associations between social skills, friendship quality, and happiness, and tested a mediational model positing that friendship quality would mediate the relationship between social skills and happiness among American and Malaysian college students. Although American students reported significantly higher levels of psychosocial well-being than Malaysian students, the study variables were positively associated with each other in both cultures. More importantly, findings supported the proposed model in both groups. Results suggest that part of the reason why social skills are associated with positive psychological well-being is because of friendship experiences. Overall, the findings of the present study reinforce, extend and cross-culturally generalize the presumed benefits of social skills in positive well-being elaborated by Segrin and Taylor (2007). The authors also provided suggestions for future research.
  6. Anion exchange silica monolith for capillary liquid chromatography
    Jaafar J, Watanabe Y, Ikegami T, Miyamoto K, Tanaka N
    Anal Bioanal Chem, 2008 Aug;391(7):2551-6.
    PMID: 18458888 DOI: 10.1007/s00216-008-2063-3
    An anion exchange monolithic silica capillary column was prepared by surface modification of a hybrid monolithic silica capillary column prepared from a mixture of tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTMS). The surface modification was carried out by on-column copolymerization of N-[3-(dimethylamino)propyl]acrylamide methyl chloride-quaternary salt (DMAPAA-Q) with 3-methacryloxypropyl moieties bonded as an anchor to the silica surface to form a strong anion exchange stationary phase. The columns were examined for their performance in liquid chromatography (LC) and capillary electrochromatography (CEC) separations of common anions. The ions were separated using 50 mM phosphate buffer at pH 6.6. Evaluation by LC produced an average of 30,000 theoretical plates (33 cm column length) for the inorganic anions and nucleotides. Evaluation by CEC, using the same buffer, produced enhanced chromatographic performance of up to ca. 90,000 theoretical plates and a theoretical plate height of ca. 4 mum. Although reduced efficiency was observed for inorganic anions that were retained a long time, the results of this study highlight the potential utility of the DMAPAA-Q stationary phase for anion separations.
  7. Fulltext Hemiballismus in Uncontrolled Diabetes Mellitus
    Jaafar J, Rahman RA, Draman N, Yunus NA
    Korean J Fam Med, 2018 May;39(3):200-203.
    PMID: 29788710 DOI: 10.4082/kjfm.2018.39.3.200
    Hemiballismus, a subtype of chorea, is a rare movement disorder, and is most commonly found secondary to stroke. Movements are involuntary, violent, coarse, and have a wide amplitude. There is increasing report of hemiballismus occurring in non-ketotic hyperglycemia. Spontaneous improvements or remissions were observed in many patients, and treatment should be directed towards the cause of hemiballismus. There is no randomized control trial to guide clinicians in deciding the best treatment option when managing hemiballismus. Symptomatic treatment includes the use of drugs such as dopamine receptor blocker and tetrabenazine. Surgical treatment is reserved for severe, persistent, and disabling hemiballismus. This case is of an elderly woman with long standing uncontrolled diabetes who presented with abnormal movement in her left upper limb for 2 months, which resolved slowly with good control of her glucose levels. Treating physicians need to have a high index of suspicion to prevent mismanagement of the condition.
  8. Fulltext Tuberculous cold abscess of sternoclavicular joint: a case report
    Burud I, Ikram MA, Tata MD, Jaafar J
    Pan Afr Med J, 2020;36:16.
    PMID: 32774593 DOI: 10.11604/pamj.2020.36.16.20697
    Bone and joint tuberculosis is a serious medical problem; tuberculosis of sternoclavicular joint is rare. We present a case of a healthy 37-year old man with sternoclavicular joint tuberculosis. The subject presented with a three weeks history of left sternoclavicular joint painless swelling without fever or weight loss. He had no previous history of pulmonary tuberculosis. Laboratory testing revealed erythrocyte sedimentation rate of 70 mm/hour, C-reactive protein of 30 mg/liter and a normal leucocyte count. Biopsy of the lesion showed caseous necrosis and pus culture revealed Mycobacterium tuberculosis. He was treated with joint debridement and anti-tuberculous medications. Tuberculosis resolved completely but post-infection patients had residual joint arthritis. Tuberculosis may infect unusual joints such as the sternoclavicular joint.
  9. Fulltext Draft Genome Sequence of Arsenic-Resistant Microbacterium sp. Strain SZ1 Isolated from Arsenic-Bearing Gold Ores
    Mohd Bahari Z, Ibrahim Z, Jaafar J, Shahir S
    Genome Announc, 2017 Oct 26;5(43).
    PMID: 29074663 DOI: 10.1128/genomeA.01183-17
    Microbacterium sp. strain SZ1 isolated from gold ores of a Malaysia gold mine was found to be highly resistant to arsenic. Here, we report the draft genome sequence of SZ1, which may provide further insights into understanding its arsenic resistance mechanism. In this draft genome, a complete set of ars operons and two additional scattered ars genes were encoded.
  10. Advances in Drug Discovery: Impact of Genomics and Role of Analytical Instrumentation
    Vijaya Bhaskar Reddy A, Yusop Z, Jaafar J, Madhavi V, Madhavi G
    Curr Drug Discov Technol, 2016;13(4):211-224.
    PMID: 27697028
    Drug discovery is a highly complicated, tedious and potentially rewarding approach associated with great risk. Pharmaceutical companies literally spend millions of dollars to produce a single successful drug. The drug discovery process also need strict compliance to the directions on manufacturing and testing of new drug standards before their release into market. All these regulations created the necessity to develop advanced approaches in drug discovery. The contributions of advanced technologies including high resolution analytical instruments, 3-D biological printing, next-generation sequencing and bioinformatics have made positive impact on drug discovery & development. Fortunately, all these advanced technologies are evolving at the right time when new issues are rising in drug development process. In the present review, we have discussed the role of genomics and advanced analytical techniques in drug discovery. Further, we have also discussed the significant advances in drug discovery as case studies.
  11. Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance
    A VBR, Yusop Z, Jaafar J, Aris AB, Majid ZA, Umar K, et al.
    J Pharm Biomed Anal, 2016 Sep 05;128:141-148.
    PMID: 27262107 DOI: 10.1016/j.jpba.2016.05.026
    In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis.
  12. Identification, control strategies, and analytical approaches for the determination of potential genotoxic impurities in pharmaceuticals: a comprehensive review
    Reddy AV, Jaafar J, Umar K, Majid ZA, Aris AB, Talib J, et al.
    J Sep Sci, 2015 Mar;38(5):764-79.
    PMID: 25556762 DOI: 10.1002/jssc.201401143
    Potential genotoxic impurities in pharmaceuticals at trace levels are of increasing concern to both pharmaceutical industries and regulatory agencies due to their possibility for human carcinogenesis. Molecular functional groups that render starting materials and synthetic intermediates as reactive building blocks for small molecules may also be responsible for their genotoxicity. Determination of these genotoxic impurities at trace levels requires highly sensitive and selective analytical methodologies, which poses tremendous challenges on analytical communities in pharmaceutical research and development. Experimental guidance for the analytical determination of some important classes of genotoxic impurities is still unavailable in the literature. Therefore, the present review explores the structural alerts of commonly encountered potential genotoxic impurities, draft guidance of various regulatory authorities in order to control the level of impurities in drug substances and to assess their toxicity. This review also describes the analytical considerations for the determination of potential genotoxic impurities at trace levels and finally few case studies are also discussed for the determination of some important classes of potential genotoxic impurities. It is the authors' intention to provide a complete strategy that helps analytical scientists for the analysis of such potential genotoxic impurities in pharmaceuticals.
  13. Biosorption of As (III) by non-living biomass of an arsenic-hypertolerant Bacillus cereus strain SZ2 isolated from a gold mining environment: equilibrium and kinetic study
    Mohd Bahari Z, Ali Hamood Altowayti W, Ibrahim Z, Jaafar J, Shahir S
    Appl Biochem Biotechnol, 2013 Dec;171(8):2247-61.
    PMID: 24037600 DOI: 10.1007/s12010-013-0490-x
    The ability of non-living biomass of an arsenic-hypertolerant Bacillus cereus strain SZ2 isolated from a gold mining environment to adsorb As (III) from aqueous solution in batch experiments was investigated as a function of contact time, initial As (III) concentration, pH, temperature and biomass dosage. Langmuir model fitted the equilibrium data better in comparison to Freundlich isotherm. The maximum biosorption capacity of the sorbent, as obtained from the Langmuir isotherm, was 153.41 mg/g. The sorption kinetic of As (III) biosorption followed well the pseudo-second-order rate equation. The Fourier transform infrared spectroscopy analysis indicated the involvement of hydroxyl, amide and amine groups in As (III) biosorption process. Field emission scanning electron microscopy-energy dispersive X-ray analysis of the non-living B. cereus SZ2 biomass demonstrated distinct cell morphological changes with significant amounts of As adsorbed onto the cells compared to non-treated cells. Desorption of 94 % As (III) was achieved at acidic pH 1 showing the capability of non-living biomass B. cereus SZ2 as potential biosorbent in removal of As (III) from arsenic-contaminated mining effluent.
  14. Online preconcentration of arsenic compounds by dynamic pH junction-capillary electrophoresis
    Jaafar J, Irwan Z, Ahamad R, Terabe S, Ikegami T, Tanaka N
    J Sep Sci, 2007 Feb;30(3):391-8.
    PMID: 17396598
    An online preconcentration technique by dynamic pH junction was studied to improve the detection limit for anionic arsenic compounds by CE. The main target compound is roxarsone, or 3-nitro-4-hydroxyphenylarsonic acid, which is being used as an animal feed additive. The other inorganic and organoarsenic compounds studied are the possible biotransformation products of roxarsone. The arsenic species were separated by a dynamic pH junction in a fused-silica capillary using 15 mM phosphate buffer (pH 10.6) as the BGE and 15 mM acetic acid as the sample matrix. CE with UV detection was monitored at a wavelength of 192 nm. The influence of buffer pH and concentration on dynamic pH junction were investigated. The arsenic species focusing resulted in LOD improvement by a factor of 100-800. The combined use of C18 and anion exchange SPE and dynamic pH junction to CE analysis of chicken litter and soils helps to increase the detection sensitivity. Recoveries of spiked samples ranged between 70 and 72%.
  15. Fulltext A review of dengue fever incidence in Kota Bharu, Kelantan, Malaysia during the years 1998-2003
    Hussin N, Jaafar J, Naing NN, Mat HA, Muhamad AH, Mamat MN
    Southeast Asian J. Trop. Med. Public Health, 2005 Sep;36(5):1179-86.
    PMID: 16438143
    Dengue is the most common and widespread arthropod borne arboviral infection in the world today. It is estimated that there are at least 100 million cases of dengue fever (DF) annually and 500,000 cases of dengue hemorrhagic fever (DHF) which require hospitalization. In Malaysia, it has become a major public health problem. Malaysia recorded 19,544 dengue cases in 1997, the highest recorded since the disease was made notifiable in the country. Of 19,544 cases, 806 were DHF with 50 deaths. The objectives of this analysis were to describe the incidence of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan, Malaysia for the years 1998-2003 and to explore the characteristics of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan, Malaysia for years 1998-2003. A total of 4,716 dengue cases were notified involving 4,476 (94.9%) DF and 240 (5.1%) DHF cases, which increased though the years. The highest incidence was in January (701 or 14.9%), while the lowest was in May (188 or 4.0%). Forty percent of cases (n=1,890) were in the 15-29 year old group. The Majority were Malays (4,062 or 86.1%) and 2,602 or 55.2% were male. A total of 4,477 cases (95%) were local cases and 4,289 or 91% came from the urban area. For priority areas, 3,772 (80%) were from priority 1. More than half the cases had positive serology results. All symptoms occurred in more than 96% of cases and fever was the commonest (99.7%). The mean values for age, temperature, systolic and diastolic blood pressure (BP) were 27.8 +/- 15.4 years, 37.9 +/- 0.90 degrees C, 115 +/- 15.2 mmHg and 73 +/- 11.1 mmHg, respectively. The mean value for the time interval between the onset of symptoms and diagnosis, onset of symptoms and notification and time of diagnosis to notification were 5.1 +/- 2.3, 5.9 +/- 2.5 and 0.8 +/- 1.1 days, respectively. There were associations between the types of dengue and classification, area and priority area. Among the symptoms, the association was only seen in joint pain. The mean significant differences between DF and DHF were found in age and systolic blood pressure. The incidence of dengue in Kota Bharu is comparable to that in Malaysia. The increase in the number of cases needs to be addressed promptly with effective surveillance, prevention and control programs.
  16. Incorporation of N-doped TiO2 nanorods in regenerated cellulose thin films fabricated from recycled newspaper as a green portable photocatalyst
    Mohamed MA, Salleh WN, Jaafar J, Ismail AF, Abd Mutalib M, Jamil SM
    Carbohydr Polym, 2015 Nov 20;133:429-37.
    PMID: 26344299 DOI: 10.1016/j.carbpol.2015.07.057
    In this work, an environmental friendly RC/N-TiO2 nanocomposite thin film was designed as a green portable photocatalyst by utilizing recycled newspaper as sustainable cellulose resource. Investigations on the influence of N-doped TiO2 nanorods incorporation on the structural and morphological properties of RC/N-TiO2 nanocomposite thin film are presented. The resulting nanocomposite thin film was characterized by FESEM, AFM, FTIR, UV-vis-NIR spectroscopy, and XPS analysis. The results suggested that there was a remarkable compatibility between cellulose and N-doped TiO2 nanorods anchored onto the surface of the RC/N-TiO2 nanocomposite thin film. Under UV and visible irradiation, the RC/N-TiO2 nanocomposite thin film showed remarkable photocatalytic activity for the degradation of methylene blue solution with degradation percentage of 96% and 78.8%, respectively. It is crucial to note that the resulting portable photocatalyst produced via an environmental and green technique in its fabrication process has good potential in the field of water and wastewater treatment application.
  17. Fulltext Toxic effect of high concentration of sonochemically synthesized polyvinylpyrrolidone-coated silver nanoparticles on Citrobacter sp. A1 and Enterococcus sp. C1
    Lau CP, Abdul-Wahab MF, Jaafar J, Chan GF, Abdul Rashid NA
    J Microbiol Immunol Infect, 2017 Aug;50(4):427-434.
    PMID: 26427880 DOI: 10.1016/j.jmii.2015.08.004
    BACKGROUND/PURPOSE: Currently, silver nanoparticles (AgNPs) have gained importance in various industrial applications. However, their impact upon release into the environment on microorganisms remains unclear. The aim of this study was to analyze the effect of polyvinylpyrrolidone-capped AgNPs synthesized in this laboratory on two bacterial strains isolated from the environment, Gram-negative Citrobacter sp. A1 and Gram-positive Enterococcus sp. C1.

    METHODS: Polyvinylpyrrolidone-capped AgNPs were synthesized by ultrasound-assisted chemical reduction. Characterization of the AgNPs involved UV-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. Citrobacter sp. A1 and Enterococcus sp. C1 were exposed to varying concentrations of AgNPs, and cell viability was determined. Scanning electron microscopy was performed to evaluate the morphological alteration of both species upon exposure to AgNPs at 1000 mg/L.

    RESULTS: The synthesized AgNPs were spherical in shape, with an average particle size of 15 nm. The AgNPs had different but prominent effects on either Citrobacter sp. A1 or Enterococcus sp. C1. At an AgNP concentration of 1000 mg/L, Citrobacter sp. A1 retained viability for 6 hours, while Enterococcus sp. C1 retained viability only for 3 hours. Citrobacter sp. A1 appeared to be more resistant to AgNPs than Enterococcus sp. C1. The cell wall of both strains was found to be morphologically altered at that concentration.

    CONCLUSION: Minute and spherical AgNPs significantly affected the viability of the two bacterial strains selected from the environment. Enterococcus sp. C1 was more vulnerable to AgNPs, probably due to its cell wall architecture and the absence of silver resistance-related genes.

  18. Simultaneous determination of three organophosphorus pesticides in different food commodities by gas chromatography with mass spectrometry
    Vijaya Bhaskar Reddy A, Yusop Z, Jaafar J, Bin Aris A, Abdul Majid Z, Umar K, et al.
    J Sep Sci, 2016 Jun;39(12):2276-83.
    PMID: 27095506 DOI: 10.1002/jssc.201600155
    A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.
  19. Development and validation of a rapid ultra high performance liquid chromatography with tandem mass spectrometry method for the simultaneous determination of darunavir, ritonavir, and tenofovir in human plasma: Application to human pharmacokinetics
    Reddy AV, Jaafar J, Aris AB, Majid ZA, Umar K, Talib J, et al.
    J Sep Sci, 2015 Aug;38(15):2580-7.
    PMID: 25989063 DOI: 10.1002/jssc.201500250
    A sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of darunavir, ritonavir and tenofovir in human plasma. Sample preparation involved a simple liquid-liquid extraction using 200 μL of human plasma extracted with methyl tert-butyl ether for three analytes and internal standard. The separation was accomplished on an Acquity UPLC BEH C18 (50 mm x 2.1 mm, 1.7 μm) analytical column using gradient elution of acetonitrile/methanol (80:20, v/v) and 5.0 mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4 mL/min. The linearity of the method ranged between 20.0 and 12 000 ng/mL for darunavir, 2.0 and 2280 ng/mL for ritonavir, and 14.0 and 1600 ng/mL for tenofovir using 200 μL of plasma. The method was completely validated for its selectivity, sensitivity, linearity, precision and accuracy, recovery, matrix effect, stability, and dilution integrity. The extraction recoveries were consistent and ranged between 79.91 and 90.04% for all three analytes and internal standard. The method exhibited good intra-day and inter-day precision between 1.78 and 6.27%. Finally the method was successfully applied for human pharmacokinetic study in eight healthy male volunteers after the oral administration of 600 mg darunavir along with 100 mg ritonavir and 100 mg tenofovir as boosters.
  20. Fulltext Development of Polysulfone Membrane via Vapor-Induced Phase Separation for Oil/Water Emulsion Filtration
    Barambu NU, Bilad MR, Bustam MA, Huda N, Jaafar J, Narkkun T, et al.
    Polymers (Basel), 2020 Oct 29;12(11).
    PMID: 33137888 DOI: 10.3390/polym12112519
    The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs as a result of the strong interaction between the hydrophobic oil droplets and the hydrophobic membrane surface. This issue has attracted research interest in developing the membrane material that possesses high hydraulic and fouling resistance performances. This research explores the vapor-induced phase separation (VIPS) method for the fabrication of a hydrophilic polysulfone (PSF) membrane with the presence of polyethylene glycol (PEG) as the additive for the treatment of oil/water emulsion. Results show that the slow nonsolvent intake in VIPS greatly influences the resulting membrane structure that allows the higher retention of the additive within the membrane matrix. By extending the exposure time of the cast film under humid air, both surface chemistry and morphology of the resulting membrane can be enhanced. By extending the exposure time from 0 to 60 s, the water contact angle decreases from 70.28 ± 0.61° to 57.72 ± 0.61°, and the clean water permeability increases from 328.70 ± 8.27 to 501.89 ± 8.92 (L·m-2·h-1·bar-1). Moreover, the oil rejection also improves from 85.06 ± 1.6 to 98.48 ± 1.2%. The membrane structure was transformed from a porous top layer with a finger-like macrovoid sub-structure to a relatively thick top layer with a sponge-like macrovoid-free sub-structure. Overall results demonstrate the potential of the VIPS process to enhance both surface chemistry and morphology of the PSF membrane.
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