Displaying publications 21 - 40 of 152 in total

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  1. Khaw CC, Tan KB, Zulkarnain Zainal, Lee CK
    Bi3Zn2Ta3O14, ‘P’, was crystallised in a cubic unit cell with lattice parameter of a=10.5437 (9) Å. The material had permittivity, ε’, of around 58 and dielectric loss, tan δ, of 2.3 × 10-3 at 30oC, 1 MHz; temperature coefficient of capacitance (TCC) of -156 ppm/oC in the range of 30oC to 300oC at 1 MHz. Chemical doping was carried out at either A (Bi1.5Zn0.5-xMx)(Zn0.5Ta1.5)O7, or B site (Bi1.5Zn0.5)(Zn0.5-xMxTa1.5)O7 in search of better performance materials. Various divalent cations such as Cd2+, Ca2+, Mg2+, Ni2+, Pb2+, and Cu2+ were used as dopants. Solid solutions formed were: Bi3Zn2-xCdxTa3O14 (0≤x≤0.5), Bi3Zn2-xMgxTa3O14(0≤x≤0.2), Bi3Zn2-xNixTa3O14 (0≤x≤0.4), Bi3Zn2-xPbxTa3O14 (0≤x≤0.3), Bi3Zn2-xCaxTa3O14 (0≤x≤0.3) and Bi3Zn2-xCuxTa3O14 (0≤x≤0.1). Electrical properties of the materials were investigated using impedance spectroscopy. Conductivities of the solid solutions were higher than that of the parent material Bi3Zn2Ta3O14. These doped materials exhibited similar behaviour as Bi3Zn2Ta3O14, showing a high degree of dispersion of permittivity at low frequencies (<1 kHz) and at temperatures above 500oC. Between 100 kHz and 1000 kHz, non-frequency dependence was observed in the range of 100 – 300oC. An increase in dielectric loss below 10 kHz was observed. Dielectric loss decreased with frequencies when temperature was above 500oC. Dielectric loss of all divalent cation doped materials was higher than that of the parent material; maximum permittivity value of 68 was recorded at x = 0.3 in Bi3Zn2-xCaxTa3O14. TCC obtained in this study had negative values; no obvious correlation between TCC and composition of the doped materials can be deduced.
  2. Lee KM, Abdul Halim Abdullah, Mohd Zobir Hussein, Zulkarnain Zainal
    Sains Malaysiana, 2014;43:437-441.
    ZnO/γ-Fe2O3 catalysts were fabricated via a simple precipitation route using zinc acetate and iron acetate as the precursors and ammonia as the precipitant. The resulted nanocatalysts were subjected to heat treatment at 450°C for 2 h. The characteristics of the nanocomposite were investigated by various characterization techniques. The synthesized nanocomposite has an average particle size of 13 nm and a surface area of 17 m2/g. The photocatalytic activity of ZnO/γ- Fe2O3 nanocomposite was evaluated by photodegrading 2,4-dichlorophenoxyacetic acid (2,4-D) under UV irradiation. The results showed that ZnO/γ-Fe2O3 nanocomposite exhibited enhanced photoactivity compared to pure ZnO with almost 20% increment within 4 h of reaction time. The result indicated the applicability of ZnO/γ-Fe2O3 nanocomposite to be used as photocatalyst in removing organic pollutants in wastewater.
  3. Barkat, Anumsima Ahmad, Jamal, Parveen, Azlin Suhaida Azmi, Noorbacha, Ibrahim Ali, Zulkarnain Mohamed Idris, Arbain, Dachyar
    MyJurnal
    A therapeutic approach for treating diabetes is to decrease thepost-prandial hyperglycaemia. This is done by retarding the absorption of glucose through the inhibition of carbohydrate hydrolyzing enzymes, α-amylaseand α-glucosidase, in the digestive tract. Inhibition of both enzymes helpsto reduce the glucose level in the blood of a diabetic patient. This study was aimed to investigate the production of α-glucosidase and α-amylase inhibitors from local fruit wastes (honeydew skin, banana peel, and pineapple skin) using solid state fermentation. Each of the fruit wastes was fermented with three different types of white rot fungus Phenarochaete chrysosporium(PC), Panus tigrinusM609RQY(M6) andRO209RQY(RO2)for 7 days. Sampling was carried out starting from day 4 to day 7 to determine the enzyme inhibition activity. The samples were extracted using water prior to enzyme analysis. Most of the fruit samples showed varying degree of percentage inhibition activity depending on the sampling time. Extract of fermented banana peels with RO2 on day 4 showed the higherα-glucosidase inhibition (56.57±0.32%), followed byhoneydew extract fermented with the same fungus on the same day (39.68±0.05%). Extracts of each fruit wastesample fermented with PCshowed the least α-glucosidase inhibition (below 15%). Meanwhile for α-amylase inhibition activity, the extract from fermented honeydew skins with PCon day7 showed the highest inhibition activity i.e.98.29±0.63%. The least inhibition activity (43.37±0.54%) was observed in the extract from honeydew skins fermented withM6 on day 5. All positive resultsshowed that fruit wastes could be the alternative sourcesfor antidiabetic agent especially for α-amylase and α-glucosidase inhibitors.
  4. Azizul Isha, Nor Azah Yusof, Musa Ahmad, Dedy Suhendra, Wan Md. Zin Wan Yunus, Zulkarnain Zainal
    MyJurnal
    An artificial neural network (ANN) was applied for the determination of V(V) based on immobilized fatty hydroxamic acid (FHA) in poly(methyl methacrylate) (PMMA). Spectra obtained from the V(V)-FHA complex at single wavelengths was used as the input data for the ANN. The V(V)-FHA complex shows a limited linear dynamic range of V(V) concentration of 10 - 100 mg/ L. After training with ANN, the linear dynamic range was extended with low calibration error. A three layer feed forward neural network using backpropagation (BP) algorithm was employed in this study. The input layer consisted of single neurons, 30 neurons in hidden a layer and one output neuron was found appropriate for the multivariate calibration used. The network were trained up to 10000 epochs with 0.003 % learning rate. This reagent also provided a good analytical pedormance with reproducibility characters of the method yielding relative standard deviation (RSD) of 9.29% and 7.09% for V(V) at concentrations of 50 mg/ L and 200 mg/ L, respectively. The limit of detection of the method was 8.4 mg/ L.
  5. Iskandar Zulkarnain Alias, Zaleha Md. Isa, Osman Ali, Khalid Abdul Kadir
    Malays J Nutr, 2002;8(2):137-156.
    MyJurnal
    This study was conducted to determine the effects of increased edible palm oil consumption on community health status in the aboriginal communities in Tual Post (treatment group) and Sinderut Post (control group), Kuala Lipis, Pahang. Nutritional status, blood pressure, lipid profiles, fasting blood glucose (FBG), vitamin E (alpha-tocopherol) levels and lipid peroxidation product (malonaldehyde) levels were taken as indicators of health status. This is a pre-and post-controlled community trial in which similar variables were measured in each group. Every family of 2–6 household members was given 2–5 kg cooking palm oil per month for a period of 18 months. All subjects were measured for height (cm), weight (kg) and waist-hip ratio (WHR). For calorie intake measurement, house-to-house interviews were conducted using 24-hour dietary recall method. Blood pressure, percent body fat, lipid profiles, namely total cholesterol, high density lipoprotein cholesterol, triglyceride and fasting blood glucose (FBG) were also measured. Vitamin E (alpha-tocopherol) levels and lipid peroxidation products (MDA) were also determined. There was a significant increase (p
  6. Nurul Asma Samsudin, Zulkarnain Zainal, Lim, Hong-Ngee, Yusran Sulaiman, Chang, Sook-Keng
    MyJurnal
    Titania nanotube is gaining tremendous interest for its unique features including high
    surface area, ion-exchange ability, photocatalytic potential and prominent electrical properties. Many
    attempts were made to manipulate the unique properties of titania nanotubes for supercapacitor
    application. In this review a comprehensive list of literatures on fabrication of titania nanotubes via
    anodisation method in fluoride-based electrolytes and its application as supercapacitor are discussed.
    This review shows that the nanotube morphology can be optimized by varying the anodisation
    parameter such as electrolyte concentration, pH, voltage, and bath temperature. The review also
    includes studies on the application of titania nanotubes as supercapacitor on improving the specific
    capacitance value by doping with metal oxides and conducting polymers.
  7. Wardatun Nadrah Mohd Amin, Zainal Abidin Talib, Zulkarnain Zainal, Hong Ngee, Lim, Sook Keng, Chang
    MyJurnal
    Quantum dots-sensitized solar cell (QDSSC) is one of the third generation solar cell that is
    the most promising low cost, easy to manufacture and highly efficient solar cell. Compared to Dyesensitized
    solar cell (DSSC), quantum dots (QDs) of QDSSC has a narrow bandgap and possess
    excellent properties such as tunable band gaps, strong light absorption and high multiple electron
    generation. Titanium dioxide or titania (TiO2) is an oxides semiconductor material that is frequently
    used as a photoanode in this photovoltaic system due to high stability under visible light illumination.
    TiO2 is also known as a good photocatalyst and an excellent choice in environmental purification. The
    efficiencies of electron injection and light harvesting in QDSSC are affected by the nature, size
    morphology, and quantity of this nanomaterial. In this review, the concept and principles of the
    QDSSCs are reviewed. The preparation and fabrication method ofTiO2 electrode in QDSSC are also
    discussed. It is worthwhile to know the architecture of TiO2 in order to enhance the efficiency of
    QDSSC.
  8. Taer E, Yanti N, Padang E, Apriwandi A, Zulkarnain Z, Haryanti NH, et al.
    J Sci Food Agric, 2023 Dec;103(15):7411-7423.
    PMID: 37431642 DOI: 10.1002/jsfa.12846
    BACKGROUND: Porous carbon electrode (PCE) is identified as a highly suitable electrode material for commercial application due to its production process, which is characterized by simplicity, cost-effectiveness and environmental friendliness. PCE was synthesized using torch ginger (Etlingera elatior (Jack) R.M. Smith) leaves as the base material. The leaves were treated with different concentrations of ZnCl2 , resulting in a supercapacitor cell electrode with unique honeycomb-like three-dimensional (3D) morphological pore structure. This PCE comprises nanofibers from lignin content and volatile compounds from aromatic biomass waste.

    RESULTS: From the characterization of physical properties, PCE-0.3 had an impressive amorphous porosity, wettability and 3D honeycomb-like structural morphology with a pore framework consisting of micropores and mesopores. According to the structural advantages of 3D hierarchical pores such as interconnected honeycombs, PCE-0.3 as supercapacitor electrode had a high specific capacitance of up to 285.89 F g-1 at 1 A. Furthermore, the supercapacitor exhibited high energy and power density of 21.54 Wh kg-1 and 161.13 W kg-1 , respectively, with a low internal resistance of 0.059 Ω.

    CONCLUSION: The results indicated that 3D porous carbon materials such as interconnected honeycombs derived from the aromatic biomass of torch ginger leaves have significant potential for the development of sustainable energy storage devices. © 2023 Society of Chemical Industry.

  9. Nasir S, Hussein MZ, Yusof NA, Zainal Z
    Nanomaterials (Basel), 2017 Jul 13;7(7).
    PMID: 28703757 DOI: 10.3390/nano7070182
    Herein, a new approach was proposed to produce reduced graphene oxide (rGO) from graphene oxide (GO) using various oil palm wastes: oil palm leaves (OPL), palm kernel shells (PKS) and empty fruit bunches (EFB). The effect of heating temperature on the formation of graphitic carbon and the yield was examined prior to the GO and rGO synthesis. Carbonization of the starting materials was conducted in a furnace under nitrogen gas for 3 h at temperatures ranging from 400 to 900 °C and a constant heating rate of 10 °C/min. The GO was further synthesized from the as-carbonized materials using the 'improved synthesis of graphene oxide' method. Subsequently, the GO was reduced by low-temperature annealing reduction at 300 °C in a furnace under nitrogen gas for 1 h. The IG/ID ratio calculated from the Raman study increases with the increasing of the degree of the graphitization in the order of rGO from oil palm leaves (rGOOPL) < rGO palm kernel shells (rGOPKS) < rGO commercial graphite (rGOCG) < rGO empty fruit bunches (rGOEFB) with the IG/ID values of 1.06, 1.14, 1.16 and 1.20, respectively. The surface area and pore volume analyses of the as-prepared materials were performed using the Brunauer Emmett Teller-Nitrogen (BET-N₂) adsorption-desorption isotherms method. The lower BET surface area of 8 and 15 m2 g-1 observed for rGOCG and rGOOPL, respectively could be due to partial restacking of GO layers and locally-blocked pores. Relatively, this lower BET surface area is inconsequential when compared to rGOPKS and rGOEFB, which have a surface area of 114 and 117 m² g-1, respectively.
  10. Nasir S, Hussein MZ, Zainal Z, Yusof NA
    Materials (Basel), 2018 Feb 13;11(2).
    PMID: 29438327 DOI: 10.3390/ma11020295
    Carbon in its single entity and various forms has been used in technology and human life for many centuries. Since prehistoric times, carbon-based materials such as graphite, charcoal and carbon black have been used as writing and drawing materials. In the past two and a half decades or so, conjugated carbon nanomaterials, especially carbon nanotubes, fullerenes, activated carbon and graphite have been used as energy materials due to their exclusive properties. Due to their outstanding chemical, mechanical, electrical and thermal properties, carbon nanostructures have recently found application in many diverse areas; including drug delivery, electronics, composite materials, sensors, field emission devices, energy storage and conversion, etc. Following the global energy outlook, it is forecasted that the world energy demand will double by 2050. This calls for a new and efficient means to double the energy supply in order to meet the challenges that forge ahead. Carbon nanomaterials are believed to be appropriate and promising (when used as energy materials) to cushion the threat. Consequently, the amazing properties of these materials and greatest potentials towards greener and environment friendly synthesis methods and industrial scale production of carbon nanostructured materials is undoubtedly necessary and can therefore be glimpsed as the focal point of many researchers in science and technology in the 21st century. This is based on the incredible future that lies ahead with these smart carbon-based materials. This review is determined to give a synopsis of new advances towards their synthesis, properties, and some applications as reported in the existing literatures.
  11. George J, Li SC, Jaafar Z, Hamid MSA
    Scientifica (Cairo), 2018;2018:4384159.
    PMID: 30057849 DOI: 10.1155/2018/4384159
    OBJECTIVE: To evaluate the efficacy of dextrose prolotherapy injection for focal supraspinatus rotator cuff tendinosis via outcomes such as functional score, range of movement, and real-time ultrasound parameters.

    MATERIALS AND METHODS: 12 adult patients with focal supraspinatus tendinosis recruited after they had less than 30% improvement in functional (DASH) scores after one month of physiotherapy following initial presentation. Seven patients had 0.5-1.0 ml of prolotherapy injection (12.5% dextrose, 0.5% lignocaine) injected into the area of focal tendinosis under ultrasound guidance. Meanwhile, five patients continued standard physiotherapy with no intervention performed. Regional area of echogenicity in decibels, DASH, range of movements of the shoulder, pain, and sleep scores were measured at baseline and at 12 weeks.

    RESULTS: The prolotherapy group showed significant improvement in shoulder abduction (p=0.030) and an improvement in sleep score (p=0.027). The echogenicity of area of tendinosis significantly increases at the end of treatment (p=0.009). However, there was a nonsignificant reduction in pain score in the injection group (43.5%) and in the control group (25%) at 12 weeks (p > 0.005).

    CONCLUSION: Ultrasound-guided intratendinous prolotherapy injection significantly improves patient's range of abduction and improves sleep within 12 weeks of treatment compared to conventional physiotherapy management.

    TRIAL REGISTRATION: This study was registered under Current Controlled Trials (UK) and given International Standard Randomised Controlled Trial Number (ISRCTN) of 43520960.

  12. Nicholas AF, Hussein MZ, Zainal Z, Khadiran T
    Nanomaterials (Basel), 2018 Sep 05;8(9).
    PMID: 30189654 DOI: 10.3390/nano8090689
    The preparation of activated carbon using palm kernel shells as the precursor (PKSAC) was successfully accomplished after the parametric optimization of the carbonization temperature, carbonization holding time, and the ratio of the activator (H₃PO₄) to the precursor. Optimization at 500 °C for 2 h of carbonization with 20% H₃PO₄ resulted in the highest surface area of the activated carbon (C20) of 1169 m² g-1 and, with an average pore size of 27 Å. Subsequently, the preparation of shape-stabilized phase change material (SSPCM-C20) was done by the encapsulation of n-octadecane into the pores of the PKSAC, C20. The field emission scanning electron microscope images and the nitrogen gas adsorption-desorption isotherms show that n-octadecane was successfully encapsulated into the pores of C20. The resulting SSPCM-C20 nano-composite shows good thermal reliability which is chemically and thermally stable and can stand up to 500 melting and freezing cycles. This research work provided a new strategy for the preparation of SSPCM material for thermal energy storage application generated from oil palm waste.
  13. Bidin MZ, Shah AM, Stanslas J, Seong CLT
    Clin Chim Acta, 2019 Aug;495:239-250.
    PMID: 31009602 DOI: 10.1016/j.cca.2019.04.069
    INTRODUCTION: Chronic kidney disease (CKD) is a silent disease. Most CKD patients are unaware of their condition during the early stages of the disease which poses a challenge for healthcare professionals to institute treatment or start prevention. The trouble with the diagnosis of CKD is that in most parts of the world, it is still diagnosed based on measurements of serum creatinine and corresponding calculations of eGFR. There are controversies with the current staging system, especially in the methodology to diagnose and prognosticate CKD.

    OBJECTIVE: The aim of this review is to examine studies that focused on the different types of samples which may serve as a good and promising biomarker for early diagnosis of CKD or to detect rapidly declining renal function among CKD patient.

    METHOD: The review of international literature was made on paper and electronic databases Nature, PubMed, Springer Link and Science Direct. The Scopus index was used to verify the scientific relevance of the papers. Publications were selected based on the inclusion and exclusion criteria.

    RESULT: 63 publications were found to be compatible with the study objectives. Several biomarkers of interest with different sample types were taken for comparison.

    CONCLUSION: Biomarkers from urine samples yield more significant outcome as compare to biomarkers from blood samples. But, validation and confirmation with a different type of study designed on a larger population is needed. More comparison studies on different types of samples are needed to further illuminate which biomarker is the better tool for the diagnosis and prognosis of CKD.

  14. Nicholas AF, Hussein MZ, Zainal Z, Khadiran T
    Sci Rep, 2020 Sep 14;10(1):15047.
    PMID: 32929140 DOI: 10.1038/s41598-020-72019-1
    The effect of the surface area of palm kernel shell activated carbon (PKSAC) on the properties of n-octadecane-encapsulated shape stabilized phase change material (SSPCM) for thermal energy storage (TES) application were studied. Various surface areas of the PKSAC were prepared using different amounts of H3PO4 treatment given to palm kernel shells from 0, 5, 10, 30 and 40% before the activation. The impregnation of n-octadecane into the different surface areas of PKSACs produced SSPCMs with different physico-chemical characteristics. The DSC analysis indicates that the higher the surface area of the PKSAC resulted in the higher freezing temperature due to the higher PCM loading that was encapsulated into the PKSAC pores. The results obtained from XRD, FESEM, Raman spectroscopy, TGA/DTG and leakage study indicate that the PKSAC is a good framework material for the development of n-octadecane-encapsulated SSPCM. It was also found that the surface area and porosity of the frameworks, activated carbon play an important role on the PCM loading percentage and their ability to be used as a thermal energy storage material.
  15. Bahrudin NN, Nawi MA, Zainal Z, Schneider R, Sabar S
    Water Sci Technol, 2020 Aug;82(3):454-467.
    PMID: 32960791 DOI: 10.2166/wst.2020.349
    Many attempts have been made to improve the photocatalytic performance of immobilized photocatalysts for large-scale applications by modification of the photocatalyst properties. In this work, immobilized bilayer photocatalyst composed of titanium dioxide (TiO2) and chitosan-montmorillonite (CS-MT) were prepared in a layer-by-layer arrangement supported on glass substrate. This arrangement allows a simultaneous occurrence of adsorption and photocatalysis processes of pollutants, whereby each layer could be independently modified and controlled to acquire the desired degree of occurring processes. It was found that the addition of MT clay within the CS composite sub-layer improved the mechanical strength of CS, reduced its swelling and shifted its absorption threshold to higher wavelengths. In addition, the band gap energy of the photocatalyst was also reduced to 2.93 eV. The immobilized TiO2/CS-MT exhibited methyl orange (MO) decolourization rate of 0.071 min-1 under light irradiation, which is better than the single TiO2 due to the synergistic processes of adsorption by CS-MT and photocatalysis by TiO2 layer. The MO dye took 6 h to achieve complete mineralization and produced sulfate and nitrate ions as the by-products. Furthermore, the immobilized TiO2/CS-MT could be reused for at least ten cycles of application without significant loss of its activity.
  16. George J, Jaafar Z, Hairi IR, Hussein KH
    J Sports Med Phys Fitness, 2020 May;60(5):749-757.
    PMID: 32141272 DOI: 10.23736/S0022-4707.20.10050-1
    BACKGROUND: The objectives of this study were to find correlation between the clinical and ultrasound grading in anterior talofibular ligament and calcaneofibular ligament tear, and to determine the sensitivity and specificity of the two stability tests among the athletes. Subsequently, we would like to propose a new grading criterion for an ultrasound examination.

    METHODS: Two blinded assessors examined thirty-five patients with a history of recent lateral ankle sprain. The first assessor performed physical examination on the injured ankle by using the anterior drawer test and talar tilt test, and the second assessor performed dynamic and static ultrasound assessment for anterior talofibular ligament and calcaneofibular ligament. The clinical laxity grading and sonographic extent of ligamentous injury was graded into a three-point scale.

    RESULTS: There was a moderate positive correlation between clinical test and ultrasound grading of anterior talofibular ligament and calcaneofibular ligament with Spearman's correlation coefficient values of 0.58 and 0.66 respectively. Clinical grading of anterior drawer test had 59.1% sensitivity (95% CI: 0.36-0.79) while ultrasound grading had 100.0% specificity (95% CI: 0.75-1.00), with positive likelihood ratio of 0.77 and negative likelihood ratio of 0.44 in detecting a complete (grade 3) anterior talofibular ligament tear (P<0.05). Meanwhile, the clinical grading of talar tilt test had 54.5% sensitivity (95% CI: 0.23-0.83) and ultrasound grading had 100.0% specificity (95% CI: 0.85-1.00), with positive likelihood ratio of 1.0 and negative likelihood ratio of 0.45 in detecting a complete grade 3 calcaneofibular ligament tear (P<0.05).

    CONCLUSIONS: The dynamic ultrasound is recommended to determine the actual degree of disruption of the ligament especially when clinical grading under-grades the degree of tear. Grade 2 tears can vary from 10% tear to 90% tear causing the clinical correlation to become less strong. We recommend a new classification for ultrasound grading of grade 2 tears, which could result in a stronger correlation between clinical and ultrasound grading.

  17. Adenan DM, Jaafar Z, Jayapalan JJ, Abdul Aziz A
    PeerJ, 2020;8:e9230.
    PMID: 32477840 DOI: 10.7717/peerj.9230
    INTRODUCTION: A high body fat coupled with low cardiopulmonary fitness and an increase in oxidative stress has been connoted as contributing factors in developing cardiovascular comorbidities. This study aimed to investigate the correlation between antioxidants and oxidative stress status with cardiopulmonary responses in women of different body mass index (BMI).

    SUBJECTS AND METHODS: Eighty female adults were recruited and divided into three groups; normal weight (n = 23), overweight (n = 28) and obese (n = 29), according to their BMI. Blood samples were obtained prior to cardiopulmonary exercise testing. Plasma samples were separated by centrifugation and analysed for enzymatic antioxidant activity including catalase, glutathione peroxidase and superoxide dismutase. Non-enzymatic antioxidant activities were assessed using 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing ability of plasma (FRAP) assays. To evaluate the oxidative stress status of subjects, levels of reactive oxygen species and malondialdehyde, the by-product of lipid peroxidation, were measured. Cardiopulmonary responses were analysed using cardiopulmonary exercise testing (CPET) which involved 15 various parameters such as peak oxygen consumption, metabolic equivalents and respiratory exchange ratio.

    RESULTS: The obese group had significantly lower ABTS radical scavenging and FRAP activities than the normal weight group. A higher catalase activity was observed in the obese group than the normal weight group. Spearman's correlation showed an inverse relationship between catalase and peak oxygen consumption, while partial correlation analysis showed inverse correlations between superoxide dismutase and respiratory frequency, ABTS activity and oxygen pulse, and between ABTS activity and cardiac output.

    CONCLUSION: Our results demonstrate a lower cardiovascular fitness and antioxidant capacity in obese women; the higher catalase activity may be a compensatory mechanism. The negative correlations found between these two parameters may indicate the potential effect of antioxidants on the cardiopulmonary system and deserve further analysis in a larger population. Nevertheless, this study provides the basis for future studies to further explore the relationships between redox status and cardiopulmonary responses. This can potentially be used to predict future risk of developing diseases associated with oxidative stress, especially pulmonary and cardiovascular diseases.

  18. Rahim MAFA, Munajat MB, Idris ZM
    Malar J, 2020 Nov 07;19(1):395.
    PMID: 33160393 DOI: 10.1186/s12936-020-03470-8
    BACKGROUND: Malaysia has already achieved remarkable accomplishments in reaching zero indigenous human malaria cases in 2018. Prompt malaria diagnosis, surveillance and treatment played a key role in the country's elimination success. Looking at the dynamics of malaria distribution during the last decades might provide important information regarding the potential challenges of such an elimination strategy. This study was performed to gather all data available in term of prevalence or incidence on Plasmodium infections in Malaysia over the last four decades.

    METHODS: A systematic review of the published English literature was conducted to identify malaria distribution from 1980 to June 2019 in Malaysia. Two investigators independently extracted data from PubMed, Scopus, Web of Science and Elsevier databases for original papers.

    RESULTS: The review identified 46 epidemiological studies in Malaysia over the 39-year study period, on which sufficient information was available. The majority of studies were conducted in Malaysia Borneo (31/46; 67.4%), followed by Peninsular Malaysia (13/46; 28.3%) and in both areas (2/46; 4.3%). More than half of all studies (28/46; 60.9%) were assessed by both microscopy and PCR. Furthermore, there was a clear trend of decreases of all human malaria species with increasing Plasmodium knowlesi incidence rate throughout the year of sampling period. The summary estimates of sensitivity were higher for P. knowlesi than other Plasmodium species for both microscopy and PCR. Nevertheless, the specificities of summary estimates were similar for microscopy (40-43%), but varied for PCR (2-34%).

    CONCLUSIONS: This study outlined the epidemiological changes in Plasmodium species distribution in Malaysia. Malaria cases shifted from predominantly caused by human malaria parasites to simian malaria parasites, which accounted for the majority of indigenous cases particularly in Malaysia Borneo. Therefore, malaria case notification and prompt malaria diagnosis in regions where health services are limited in Malaysia should be strengthened and reinforced to achieving the final goal of malaria elimination in the country.

  19. Hussein MZ, Mohd Amin JB, Zainal Z, Yahaya AH
    J Nanosci Nanotechnol, 2002 Apr;2(2):143-6.
    PMID: 12908300
    Hydrotalcite-like inorganic layers of Zn-Al, a host containing an organic moiety, 2,4-dichlorophenoxy-acetate, as a guest, was prepared by the spontaneous self-assembly method from an aqueous solution for the formation of a new layered organic-inorganic hybrid nanocomposite material. In this synthesis, the host- and guest-forming species were simultaneously included in the mother liquor, aged, and separated. Various Zn/Al ratios (R = 2, 3, and 4), concentrations of 2,4-dichlorophenoxyacetic acid (0.03-0.1 M), and pH (7 and 10) were studied to optimize the formation of the layered nancomposite. It was found that the optimum conditions for the formation of the nanocomposite were R = 4, pH 7, and concentration of 2,4-dichlorophenoxyacetic acid = 0.08 M. X-ray diffraction shows that this sample affords a nanolayered structure with a basal spacing of 24.6 A.
  20. Hussein MZ, Kuang D, Zainal Z, Teck TK
    J Colloid Interface Sci, 2001 Mar 1;235(1):93-100.
    PMID: 11237447
    Kaolin-carbon adsorbents were prepared with and without sulfuric acid pretreatment followed by activation-carbonization at 500 degrees C. The total surface area of the resulting kaolin-carbon adsorbents was found to be decreased with the increase in kaolin loading. Sulfuric acid pretreatment of the precursor prior to the carbonization-activation processes resulted in the enhancement of total surface area but reduced the micropore surface area of the resulting adsorbents. At the same time, this improved carotene adsorption capacity from red palm oil. However, recovery of carotene from the carotene-adsorbed adsorbent is only improved when the acid pretreatment of the precursor was done at a high loading percentage of activated carbon. Similarly, the peroxide value (PV) increased. A maximum removal of carotene from red palm oil was obtained at 20% kaolin loading for both adsorbents prepared with and without sulfuric acid pretreatment with about 45 and 65% carotene removal, respectively, from a 30-ppm solution. This indicates that pretreatment with sulfuric acid, prior to the activation-carbonization process, increased the carotene uptake by the resulting adsorbent. However, a further increase in the kaolin loading resulted in the decrease of carotene removal. About 3-4% of carotene adsorbed can be recovered from both types of adsorbents under optimum condition, in which the percentage recovered decreased with the increase in kaolin loading. On the other hand, the PV increased with kaolin loading at around 54-64 mEq/kg for both types of adsorbents. It was also found that carotene uptake by the adsorbents is high if the adsorbent contains a high percentage of activated carbon. Similarly, carotene recovery is high and less oxidation can be observed, as indicated by the lower PV value. Copyright 2001 Academic Press.
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