Displaying publications 381 - 400 of 1883 in total

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  1. Fulltext Investigation of vortex clouds and droplet sizes in heated water spray patterns generated by axisymmetric full cone nozzles
    Naz MY, Sulaiman SA, Ariwahjoedi B, Ku Shaari KZ
    ScientificWorldJournal, 2013;2013:796081.
    PMID: 24307881 DOI: 10.1155/2013/796081
    The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit.
    Matched MeSH terms: Pressure
  2. Fulltext Optic disc topography of normal tension glaucoma patients in Malaysia
    Abdul Rahim A, Ismail S, Ahmad Tajudin LS, Ahmad MS
    Med J Malaysia, 2013 Aug;68(4):338-42.
    PMID: 24145263 MyJurnal
    There are limited data in the literature on the optic disc topography in normal tension glaucoma (NTG) patients in Asian countries, especially in Southeast Asia. This study is aimed at comparing optic disc topography in NTG patients and a control group in Malaysia, and we discuss the literature on NTG studies in other Asian populations. A comparative cross-sectional study was conducted in two hospitals with glaucoma services in Malaysia from November 2010 to February 2012. A total of 109 eyes of 109 Malay patients were included in this study: 32 NTG patients and 77 subjects in the control group. All participants underwent a thorough ocular examination, including visual acuity, subjective refraction, anterior segment and fundus examinations, Humphrey visual field 24-2, intraocular pressure measurement, gonioscopy examination and fundus photography. Optic disc topography was assessed using the Heidelberg Retinal Tomograph III by an identified masked investigator in each hospital. NTG patients had a notably larger disc area (2.65 (0.41) vs 2.19 (0.43) mm(2), respectively), larger cupping (1.54 (0.43) vs 0.63 (0.40) mm(2), respectively), smaller retinal rim areas (1.12 (0.41) vs 1.56 (0.33) mm(2), respectively), higher cup volume (0.47 (0.28) vs 0.11 (0.19) mm(3), respectively), reduced rim volume (0.23 (0.13) vs 0.41 (0.16) mm(3), respectively), higher cup to disc area ratio (0.58 (0.14) vs 0.27 (0.15), respectively), higher linear cup to disc ratio (0.76 (0.09) vs 0.49 (0.17) mm(2), respectively), higher mean cup depth (0.37 (0.09) vs 0.22 (0.09) mm, respectively), higher maximum cup depth (0.77 (0.16) vs 0.59 (0.20) mm, respectively), higher mean of cup shape measure (-0.04 (0.06) vs -0.16 (0.07), respectively), and thinner mean retinal nerve fibre layer thickness (0.15 (0.15) vs 0.24 (0.07) mm, respectively) compared to the control group (p<0.05). In conclusion, most of the optic disc parameters were significantly different in NTG patients compared to healthy individuals in Malaysia. Our findings are comparable to those reported in NTG studies in other Asian countries.
    Matched MeSH terms: Intraocular Pressure
  3. Fulltext A report on an unusual presentation of autonomic dysreflexia
    Suhaida SS, Engkasan JP
    Med J Malaysia, 2012 Dec;67(6):616-7.
    PMID: 23770957 MyJurnal
    A 48-year-old male with complete tetraplegia C6 presented with sweating and flushing of the right half of the face and neck that recurred when lying in supine and left lateral positions. The symptoms subsided immediately upon sitting upright or lying in a right lateral position. The symptoms were associated with occasional mild head discomfort rather than headache and were accompanied by marked elevation of blood pressure, which was 190-200/120-130 mmHg compared to his previous baseline blood pressure of 80-90/50-70 mmHg, and he had a heart rate of 60-70 beats per minute. We believe that post-traumatic syringomyelia, found upon further investigation, was the cause of the Autonomic dysreflexia (AD) in this patient. He was advised to avoid the positions causing the symptoms and the progression of symptoms was monitored regularly. AD might not have been diagnosed in this patient because of the atypical and unusual presentations. Therefore, knowledge and a heightened level of awareness of this possible complication are important when treating individuals with spinal cord injury (SCI).
    Matched MeSH terms: Blood Pressure
  4. Influence of step increases in hydraulic retention time on (RS)-MCPP degradation using an anaerobic membrane bioreactor
    Yuzir A, Chelliapan S, Sallis PJ
    Bioresour Technol, 2011 Oct;102(20):9456-61.
    PMID: 21862323 DOI: 10.1016/j.biortech.2011.07.083
    The effects of different hydraulic retention time (HRT) on (RS)-MCPP utilisation was investigated by decreasing the feed flow rate in an anaerobic membrane bioreactor (AnMBR). Results showed an average COD removal efficiency of 91.4%, 96.9% and 94.4% when the reactor was operated at HRT 3, 7 and 17 d, respectively. However, when the HRT was reduced to 1d, the COD removal efficiency declined to just only 60%, confirming the AnMBR is stable to a large transient hydraulic shock loads. The (RS)-MCPP removal efficiency fluctuated from 6% to 39% at HRT 3 d, however when it was increased to 7 and 17 d, the removal efficiency increased to an average of 60% and 74.5%. In addition, (RS)-MCPP specific utilisation rates (SUR) were dependent on the HRT and gradually improved from 18 to 43 μg mg VSS(-1) d(-1) as flow rate increased.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  5. Natural occurrence of ochratoxin A contamination in commercial black and white pepper products
    Jalili M, Jinap S, Radu S
    Mycopathologia, 2010 Oct;170(4):251-8.
    PMID: 20526682 DOI: 10.1007/s11046-010-9320-7
    The concentration of ochratoxin A (OTA) in 120 commercial pepper (84 pre-packed and 36 bulk samples), which consist of local and imported white and black pepper in powder and seed form in Malaysia were determined. The objective of the study was to investigate and compare OTA concentration in black pepper and white pepper being commercialized in Malaysia. Determination method was based on HPLC with fluorescence detection coupled with immunoaffinity column clean-up step. Mobile phase consisted of acetonitrile-water-acetic acid (49.5:49.5:1.0, v/v/v), and flow rate was 1 ml/min. The LOD was 0.02 ng/g, and the average recovery values of OTA ranged from 79.5 to 92.0% in black pepper and 81.2-90.3% in white pepper. A total of 57 samples (47.5%) were contaminated with OTA ranging from 0.15 to 13.58 ng/g. The results showed that there was a significant difference between type of pepper and brands. OTA concentration in black pepper was significantly higher than white pepper (p < 0.05). The highest concentration of ochratoxin, 13.58 ng/g, was detected in a sample of black pepper seed followed by 12.64 ng/g in a sample of black pepper powder, both were bulk samples purchased from open market.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  6. TRANSCRIPTOMIC ANALYSIS OF GRACILARIA CHANGII (RHODOPHYTA) IN RESPONSE TO HYPER- AND HYPOOSMOTIC STRESSES(1)
    Teo SS, Ho CL, Teoh S, Rahim RA, Phang SM
    J Phycol, 2009 Oct;45(5):1093-9.
    PMID: 27032354 DOI: 10.1111/j.1529-8817.2009.00724.x
    Osmotic stress is one of the most significant natural abiotic stresses that occur in the intertidal zones. Seaweeds may physiologically acclimate to changing osmolarity by altering their transcriptome. Here, we investigated the transcriptomic changes of Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia in response to hyper- and hypoosmotic stresses using a cDNA microarray approach. Microarray analysis revealed that 199 and 200 genes from ∼3,300 genes examined were up- and down-regulated by >2-fold in seaweed samples treated at 50 parts per thousand (ppt) artificial seawater (ASW) compared with those at 30 ppt ASW, respectively. The number of genes that were up- and down-regulated by >2-fold in seaweed samples treated at 10 ppt ASW compared with those at 30 ppt ASW were 154 and 187, respectively. A majority of these genes were only differentially expressed under hyper- or hypoosmotic conditions, whereas 67 transcripts were affected by both stresses. The findings of this study have shed light on the expression profiles of many transcripts during the acclimation of G. changii to hyperosmotic and hypoosmotic conditions. This information may assist in the prioritization of genes to be examined in future studies.
    Matched MeSH terms: Osmotic Pressure
  7. The Production of 9-methoxycanthin-6-one from Callus Cultures of (Eurycoma longifolia Jack) Tongkat Ali
    Maziah M, Rosli N
    Methods Mol Biol, 2009;547:359-69.
    PMID: 19521859 DOI: 10.1007/978-1-60327-287-2_29
    Plant cell culture technology is potentially useful in producing high-valued secondary metabolites. Eurycoma longifolia root extracts are consumed as a health tonic but more popularly used as an aphrodisiac. Studies on the aphrodisiac properties and the possible compounds involved have been widely studied. There are many potentially useful compounds reported from the root extracts of E. longifolia. However, studies on the in vitro production of useful compounds from this plant have not been reported. This chapter will describe methods of callus induction and extraction of 9-methoxycanthin-6-one from E. longifolia Jack explants with emphasis on the tap and fibrous roots. This compound, known to have anti-tumour activity, is present in intact plant parts and in callus tissues of different explants.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  8. Fulltext Poor blood pressure control and its associated factors among older people with hypertension: A cross-sectional study in six public primary care clinics in Malaysia
    Cheong AT, Sazlina SG, Tong SF, Azah AS, Salmiah S
    Malays Fam Physician, 2015;10(1):19-25.
    PMID: 26425291 MyJurnal
    INTRODUCTION: Hypertension is highly prevalent in the older people. Chronic disease care is a major burden in the public primary care clinics in Malaysia. Good blood pressure (BP) control is needed to reduce the morbidity and mortality of cardiovascular disease (CVD). This study aimed to determine the status of BP control and its associated factors among older people with hypertension in public primary care clinics.
    MATERIALS AND METHODS: A cross-sectional study on hypertensive patients aged 18 years and above was conducted in six public primary care clinics in Federal Territory, Malaysia. A total of 1107 patients were selected via systematic random sampling. Data from 441 (39.8%) patients aged 60 years and more were used in this analysis. BP control was determined from the average of two BP readings measured twice at an interval of 5 min. For patients without diabetes, poor BP control was defined as BP of ≥140/90 mm Hg and ≥150/90 for the patients aged 80 years and more. For patients with diabetes, poor control was defined as BP of ≥140/80 mm Hg.
    RESULTS: A total of 51.7% (n = 228) of older patients had poor BP control. The factors associated with BP control were education level (p = 0.003), presence of comorbidities (p = 0.015), number of antihypertensive agents (p = 0.001) and number of total medications used (p = 0.002). Patients with lower education (less than secondary education) (OR = 1.7, p = 0.008) and the use of three or more antihypertensive agents (OR = 2.0, p = 0.020) were associated with poor BP control.
    CONCLUSION: Among older people with hypertension, those having lower education level, or using three or more antihypertensive agents would require more attention on their BP control.
    Matched MeSH terms: Blood Pressure
  9. Performance of an extended aeration-microfiltration (EAM) reactor in treating high strength industrial wastewater
    Noor MJ, Muyibi SA, Ahmed T, Ghazall AH, Jusoh A, Idris A, et al.
    Water Sci Technol, 2002;46(9):331-8.
    PMID: 12448486
    A laboratory study was conducted on an Extended Aeration-Microfiltration (EAM) reactor in treating a food industry wastewater. The reactor contained horizontally laid hollow fibre microfiltration (MF) units that were fully submerged. The MF units were connected to a peristaltic pump that was used to extract permeate continuously under suction pressure. Continuous aeration from beneath the modules provided the crossflow effect to the MF units. Active activated sludge was used in the start-up where the sludge was mixed together with the feed water at a Food/Microorganisms (F/M) value of about 0.1. Primary effluent with Chemical Oxygen Demand (COD) values ranged between 1,500 and 3,000 mg/l was used as feed water. The EAM reactor was operated for nearly three months without initiating cleaning of the MF units. A suction pressure of 0.9 bar and Mixed Liquor Suspended Solids (MLSS) of over 5,500 mg/l were reached when nearing the end of the three month operation period. Permeate COD and turbidity reduction of over 97% and 99% respectively, were achieved. Prior to this, the MF module arrangements were studied; where vertically arranged modules were found to perform poorly as compared to the horizontally laid modules, in terms of clean water permeate flux.
    Matched MeSH terms: Pressure
  10. Simple high-performance liquid chromatographic method for simultaneous determination of fusidic Acid and betamethasone dipropionate in a cream formulation
    Peh KK, Tan YT
    Int J Pharm Compd, 2000 May-Jun;4(3):229-31.
    PMID: 23986007
    A simple and selective high-performance liquid chromatography (HPLC) method using ultraviolet detection was developed for simultaneous determination of fusidic acid and betamethasone dipropionate in a cream formulation. A Supelcosil LC18 column was used for chromatographic separation. The mobile phase consisted of acetonitrile and 0.01 M disodium hydrogen orthophosphate (70:30, % v/v) adjusted to pH 6 with glacial acetic acid. Analysis was run at a flow rate of 1.0 mL/minute with the detector operating at 235 nm. The standard calibration curve was linear over a concentration range of 0.3 to 1.2 mg/mL for fusidic acid and 9.6 to 38.4 micrograms/mL for betamethasone dipropionate. The average recovery values for fusidic acid and betamethasone dipropionate were almost 100%. The within-run and between-run coefficient of variation and percent error values for the two drugs were all less than 2% and +/- 3%, respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  11. The effect of mivacurium pretreatment on intra-ocular pressure changes induced by suxamethonium
    Chiu CL, Lang CC, Wong PK, Delilkan AE, Wang CY
    Anaesthesia, 1998 May;53(5):501-5.
    PMID: 9659028
    Forty patients without eye disease, undergoing elective nonophthalmic surgery, were studied in a double-blind, randomised, placebo-controlled study evaluating the efficacy of mivacurium pretreatment in attenuating the rise in intra-ocular pressure in response to suxamethonium administration, laryngoscopy and intubation. The patients were randomly allocated to receive either mivacurium 0.02 mg.kg-1 or normal saline as pretreatment 3 min before a rapid sequence induction technique using alfentanil, propofol and suxamethonium. Suxamethonium induced a significant increase in intra-ocular pressure in the control group but not in the mivacurium pretreatment group (mean (SEM) increase = 3.5 (1.2) mmHg vs. 0.4 (0.8) mmHg, p < 0.05). There was a decrease in intra-ocular pressure in both groups after laryngoscopy and intubation with no significant difference between the two groups. These results show that mivacurium pretreatment is effective in preventing the increase in intra-ocular pressure after suxamethonium administration.
    Matched MeSH terms: Blood Pressure/drug effects; Intraocular Pressure/drug effects*
  12. Fulltext The outcome of trabeculectomy for primary glaucoma in adult patients in UKM
    Sharif FM, Selvarajah S
    Med J Malaysia, 1997 Mar;52(1):17-25.
    PMID: 10968049
    A clinical audit was conducted for a 4-year period at the Universiti Kebangsaan Malaysia (UKM) Ophthalmology Department in which 61 eyes of adult patients with primary glaucoma underwent trabeculectomies without antimetabolites. At a 2-year follow-up duration, successful trabeculectomies as defined by intraocular pressure below 20 mm Hg without additional glaucoma medication were 62% for primary open-angle glaucoma, 48% for primary acute angle-closure glaucoma and 43% for chronic angle-closure glaucoma. 50.8% of eyes were without complications while 49.2% had complications. Shallow anterior chamber (22.9%) and hyphaema (19.7%) were the two commonest complications.
    Matched MeSH terms: Intraocular Pressure
  13. Fulltext "Miotic-induced retinal detachment": a case report
    Singh M
    Med J Malaysia, 1985 Jun;40(2):136-8.
    PMID: 3834285
    A rare case of pilocarpine-induced retinal detachment occurring in the only useful myopic eye of a young Chinese woman is described. Problems of treating raised intraocular pressure in high-risk cases of retinal detachment are discussed.
    Matched MeSH terms: Intraocular Pressure
  14. Fulltext Characterization of Hybrid Oil Palm Empty Fruit Bunch/Woven Kenaf Fabric-Reinforced Epoxy Composites
    Hanan F, Jawaid M, Paridah MT, Naveen J
    Polymers (Basel), 2020 Sep 09;12(9).
    PMID: 32916779 DOI: 10.3390/polym12092052
    In this research, the physical, mechanical and morphological properties of oil palm empty fruit bunch (EFB) mat/woven kenaf fabric-reinforced epoxy composites have been investigated. The oil palm EFB/woven kenaf fabrics were varied, with weight ratios of 50/0 (T1), 35/15 (T2), 25/25 (T3), 15/35 (T4) and 0/50 (T5). The composites were fabricated using a simple hand lay-up technique followed by hot pressing. The result obtained shows that an increase in kenaf fiber content exhibited higher tensile and flexural properties. On the other hand, the opposite trend was observed in the impact strength of hybrid composites, where an increase in kenaf fiber content reduced the impact strength. This can be corroborated with the physical properties analysis, where a higher void content, water absorption and thickness swelling were observed for pure oil palm EFB (T1) composites compared to other samples. The scanning electron microscopy analysis results clearly show the different failure modes of the tensile fractured samples. Statistical analysis was performed using one-way ANOVA and shows significant differences between the obtained results.
    Matched MeSH terms: Pressure
  15. HPLC-Based Qualitative and Quantitative Analyses of Alkaloids in Chewable Areca Products from Different Geographic Regions
    Cao M, Liu Y, Yuan H, Qiu Y, Xie Q, Yi P, et al.
    J AOAC Int, 2020 Sep 01;103(5):1400-1405.
    PMID: 33241395 DOI: 10.1093/jaoacint/qsaa048
    BACKGROUND: Chewable areca products are popular in Asian countries, including India, Pakistan, Malaysia, and China. The major alkaloids present in areca products are guvacine, arecaidine, guvacoline, and arecoline which cause carcinogenicity and addiction.

    OBJECTIVE: The objective of this study was the quantitative analysis of the alkaloid content of areca chewable products from different countries and regions using HPLC-UV, as well as the benefit of their safety evaluation products.

    METHOD: An HPLC-UV method was established for qualitative and quantitative analyses of 65 batches of areca chewable products from different countries and regions. Additionally, similarity evaluation of chromatographic fingerprints was applied for data analysis.

    RESULTS: These results reveal a significant variation in the levels of areca alkaloids among tested products, specifically guvacoline (0.060-1.216 mg/g), arecoline (0.376-3.592 mg/g), guvacine (0.028-1.184 mg/g), and arecaidine (0.184-1.291 mg/g). There were significant differences in the alkaloid content of areca chewable products from different producing areas.

    CONCLUSIONS: The method will be useful in the safety evaluation of different areca chewable products.

    HIGHLIGHTS: The established HPLC-UV method can be adopted for safety evaluation of areca chewable products from different countries and regions due to its general applicability.

    Matched MeSH terms: Chromatography, High Pressure Liquid
  16. Fulltext Thymoquinone content in marketed black seed oil in Malaysia
    Alkhatib H, Mawazi SM, Al-Mahmood SMA, Zaiter A, Doolaanea AA
    J Pharm Bioallied Sci, 2020 07 18;12(3):284-288.
    PMID: 33100788 DOI: 10.4103/jpbs.JPBS_208_20
    Thymoquinone (TQ) is the major active compound in black seed oil (BSO). Many pharmacological effects of TQ, such as anti-inflammatory, hypoglycemic, antioxidant, immune stimulator, and anticancer, have been reported. TQ can be considered as a biomarker for BSO, but its content in the commercial products is rarely reported. TQ content varies based on the oil source and extraction method. This study aimed to quantify the TQ content in the commercial BSO products in Malaysia and to evaluate whether the products can be used as a source of TQ for therapeutic benefits. TQ was quantified using an established high-performance liquid chromatography (HPLC) method. TQ human equivalent dose (HED) was calculated based on reported animal studies from literature, and theoretical BSO amount containing the TQ dose was calculated based on the HPLC analysis. TQ content in the commercial BSO products ranged from 0.07% wt/wt to 1.88% wt/wt. The product with the highest TQ concentration is approximately 27-fold higher than the product with the lowest TQ concentration. Consequently, theoretical BSO amounts needed for specific diseases varied and some products cannot provide practical amount of TQ. This study recommends the regulation of TQ content in BSO and suggests that the BSO might be fortified with extra TQ to be effectively used in some diseases.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  17. Diagnosis and Management of Resistant Hypertension: A Case Report
    Zhang ZY, Yang WY, Dominiczak AF, Wang JG, Wu Y, Almustafa B, et al.
    Hypertension, 2019 11;74(5):1064-1067.
    PMID: 31422692 DOI: 10.1161/HYPERTENSIONAHA.119.13206
    Matched MeSH terms: Blood Pressure Determination/methods; Blood Pressure Monitoring, Ambulatory/methods*
  18. Troubleshooting and maintenance of high-performance liquid chromatography during herbicide analysis: an overview
    Tayeb MA, Ismail BS, Khairiatul Mardiana J, Goh CT
    Sains Malaysiana, 2016;45:237-245.
    Glufosinate ammonium or ammonium salt (ammonium-(2RS)-2-amino-4- (methylphosphinato) butyric acid; C5H15N2O4P) is a commonly used polar herbicide in Malaysia and present in a variety of environmental waters at the sub-ppb level. Thus, glufosinate ammonium is analyzed in soil and water using high-performance liquid chromatography (HPLC), which is a complex yet the most powerful analysis tool. HPLC is tremendously sensitive and highly automated and HPLC instrumentation and machinery have improved over the years. However, typical problems are still encountered. HPLC users and advanced learners require help in identifying, separating and correcting typical problems. All HPLC systems consist of similar basic components. Although it is a modular system, trouble can occur in each component and change the overall performance. Resolving these problems may be expensive. This review describes the different aspects of HPLC, particularly troubleshooting, common problems and easy guidelines for maintenance.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  19. Fulltext Enhanced Thermal and Dynamic Mechanical Properties of Synthetic/Natural Hybrid Composites with Graphene Nanoplateletes
    Jesuarockiam N, Jawaid M, Zainudin ES, Thariq Hameed Sultan M, Yahaya R
    Polymers (Basel), 2019 Jun 26;11(7).
    PMID: 31247898 DOI: 10.3390/polym11071085
    The aim of the present research work is to enhance the thermal and dynamic mechanical properties of Kevlar/Cocos nucifera sheath (CS)/epoxy composites with graphene nano platelets (GNP). Laminates were fabricated through the hand lay-up method followed by hot pressing. GNP at different wt.% (0.25, 0.5, and 0.75) were incorporated with epoxy resin through ultra-sonication. Kevlar/CS composites with different weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) were fabricated while maintaining a fiber/matrix weight ratio at 45/55. Thermal degradation and viscoelastic properties were evaluated using thermogravimetric analysys (TGA), differential scanning calorimetric (DSC) analysis, and a dynamic mechanical analyser (DMA). The obtained results revealed that Kevlar/CS (25/75) hybrid composites at 0.75 wt.% of GNP exhibited similar thermal stability compared to Kevlar/epoxy (100/0) composites at 0 wt.% of GNP. It has been corroborated with DSC observation that GNP act as a thermal barrier. However, DMA results showed that the Kevlar/CS (50/50) hybrid composites at 0.75 wt.% of GNP exhibited almost equal viscoelastic properties compared to Kevlar/epoxy (100/0) composites at 0 wt.% GNP due to effective crosslinking, which improves the stress transfer rate. Hence, this research proved that Kevlar can be efficiently (50%) replaced with CS at an optimal GNP loading for structural applications.
    Matched MeSH terms: Pressure
  20. Highly sensitive and selective determination of malathion in vegetable extracts by an electrochemical sensor based on Cu-metal organic framework
    Al'Abri AM, Abdul Halim SN, Abu Bakar NK, Saharin SM, Sherino B, Rashidi Nodeh H, et al.
    J Environ Sci Health B, 2019;54(12):930-941.
    PMID: 31407615 DOI: 10.1080/03601234.2019.1652072
    This article demonstrates the first application of a copper-based porous coordination polymer (BTCA-P-Cu-CP) as a carbon paste electrode (CPE) modifier for the detection of malathion. The electrochemical behavior of BTCA-P-Cu-CP/CPE was explored using cyclic voltammetry (CV) while chrono-amperometry methods were applied for the analytical evaluation of the sensor performance. Under optimized conditions, the developed sensor exhibited high reproducibility, stability, and wide dynamic range (0.6-24 nM) with the limits of detection and sensitivity equal to 0.17 nM and 5.7 µAnMcm-1, respectively, based on inhibition signal measurement. Furthermore, the presence of common coexisting interfering species showed a minor change in signals (<4.4%). The developed sensor has been applied in the determination of malathion in spiked vegetable extracts. It exhibited promising results in term of fast and sensitive determination of malathion in real samples at trace level with recoveries of 91.0 to 104.4%. (RSDs < 5%, n = 3). A comparison of the two studied techniques showed that the HPLC technique is unable to detect malathion when the concentration is lower than 1.8 µM while 0.006 µM is detected with appropriate RSDs 0.2-5.2% (n = 3) by amperometric method. Due to the high sensitivity and selectivity, this new electrochemical sensor will be useful for monitoring trace malathion in real samples.
    Matched MeSH terms: Chromatography, High Pressure Liquid
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