Browse publications by year: 2013

  1. Khan TM, Emeka P, Khan AH
    Ther Innov Regul Sci, 2013 Mar;47(2):198-202.
    PMID: 30227531 DOI: 10.1177/2168479012462214
    Providing drug information has become one of the essential job functions of a community pharmacist. To ensure the availability of up-to-date information, pharmacists should have access to reliable drug information. The current study was an effort to explore the use of drug information resources at a community pharmacy in Penang Island, Malaysia. This study also explores nonprescription requests, with a special emphasis on pharmacists' agreement to dispense medicines without a prescription. A cross-sectional study was performed among the community pharmacists practicing in 3 populous areas of Penang Island. Face-to-face interviews were conducted using a 24-item questionnaire. The response rate was 67.3%. Online drug information, compared with other resources, was preferred by a majority of pharmacists (n = 19, 51.4%). Of the pharmacists, 28 (75.7%) mentioned that patients often make a nonprescription drug request for anti-inflammatory agents, painkillers, and medicines for cough and flu. In about 59.5% of the cases, pharmacists dispensed the requested medicine without question. Most of the pharmacists stated they have dispensed painkillers, creams and ointments, antifungals, body tonics, and inhalers without prescription.
  2. Ng SC, Tang W, Ching JY, Wong M, Chow CM, Hui AJ, et al.
    Gastroenterology, 2013 Jul;145(1):158-165.e2.
    PMID: 23583432 DOI: 10.1053/j.gastro.2013.04.007
    BACKGROUND & AIMS: Inflammatory bowel diseases (IBD) are becoming more common in Asia, but epidemiologic data are lacking. The Asia-Pacific Crohn's and Colitis Epidemiology Study aimed to determine the incidence and phenotype of IBD in 8 countries across Asia and in Australia.

    METHODS: We performed a prospective, population-based study of IBD incidence in predefined catchment areas, collecting data for 1 year, starting on April 1, 2011. New cases were ascertained from multiple overlapping sources and entered into a Web-based database. Cases were confirmed using standard criteria. Local endoscopy, pathology, and pharmacy records were searched to ensure completeness of case capture.

    RESULTS: We identified 419 new cases of IBD (232 of ulcerative colitis [UC], 166 of Crohn's disease [CD], and 21 IBD-undetermined). The crude annual overall incidence values per 100,000 individuals were 1.37 for IBD in Asia (95% confidence interval: 1.25-1.51; 0.76 for UC, 0.54 for CD, and 0.07 for IBD-undetermined) and 23.67 in Australia (95% confidence interval: 18.46-29.85; 7.33 for UC, 14.00 for CD, and 2.33 for IBD-undetermined). China had the highest incidence of IBD in Asia (3.44 per 100,000 individuals). The ratios of UC to CD were 2.0 in Asia and 0.5 in Australia. Median time from symptom onset to diagnosis was 5.5 months (interquartile range, 1.4-15 months). Complicated CD (stricturing, penetrating, or perianal disease) was more common in Asia than Australia (52% vs 24%; P = .001), and a family history of IBD was less common in Asia (3% vs 17%; P < .001).

    CONCLUSIONS: We performed a large-scale population-based study and found that although the incidence of IBD varies throughout Asia, it is still lower than in the West. IBD can be as severe or more severe in Asia than in the West. The emergence of IBD in Asia will result in the need for specific health care resources, and offers a unique opportunity to study etiologic factors in developing nations.

    MeSH terms: Adult; Asia/epidemiology; Australia/epidemiology; Female; Humans; Male; Middle Aged; Phenotype; Prospective Studies; Inflammatory Bowel Diseases/diagnosis; Inflammatory Bowel Diseases/drug therapy; Inflammatory Bowel Diseases/epidemiology*; Incidence
  3. Ofori-Boateng C, Lee KT
    Food Sci Nutr, 2013 05;1(3):209-221.
    PMID: 29387349 DOI: 10.1002/fsn3.22
    Oil palm (Elaeis guineensis Jacq.) fronds (OPF) are the most abundant oil palm solid wastes that are generated during oil palm agriculture and harvest. Palm oil and some other palm wastes have been reported to contain high concentrations of carotenoids with vital bioactive properties. However, the extraction and quantification of carotenoids from OPF have not been reported. In this study, ultrasonic-assisted extraction, HPLC-FLD for quantification, and response surface methodology (RSM) for optimization of β-carotene, lutein, and zeaxanthin from OPF extracts were investigated. The effects of extraction temperature (X1: 30-70°C), extraction time (X2: 10-50 min), and solvent-sample ratio (X3: 10-50 mL/g) on the recovery of β-carotene (Y1), lutein (Y2), and zeaxanthin (Y3) were investigated using three-level Box-Behnken design (BBD) experiment. At a desirability of 1, the optimum extraction conditions for β-carotene (30.14°C, 37.11 min, and 23.18 mL/g), lutein (30.00°C, 39.09 min, and 19.24 mL/g), and zeaxanthin (30.09°C, 36.76 min, and 22.38 mL/g) yielded carotenoid concentrations of 17.95 μg/g dry weight (DW), 261.99 μg/g DW, and 29.99 μg/g DW, respectively.
  4. Shafie AA, Hassali MA, Mohamad Yahaya AH
    Value Health Reg Issues, 2013 May;2(1):107-117.
    PMID: 29702838 DOI: 10.1016/j.vhri.2013.02.005
    OBJECTIVE: To describe the health-related quality of life (HRQOL) among nonprescription medicine customers in Malaysia and the factors that affect it.

    METHODS: A nationwide cross-sectional survey was conducted among pharmacy customers in 59 randomly selected community pharmacies in Malaysia. The self-administered questionnaire included the EuroQoL five-dimensional (EQ-5D) questionnaire, the EuroQol visual analogue scale (EQ-VAS), nonprescription medicines purchase, and demographic questions. Data were analyzed by using the multivariate analysis of variance and multiple logistic regressions.

    RESULTS: A total of 2729 customers enrolled in this study, with a mean EQ-5D questionnaire score of 0.92±0.15 and a mean EQ-VAS score of 69.92±24.80. Compared with the Malaysian adult population, nonprescription medicine customers have a lower mean EQ-5D questionnaire score (t =-4.49, P<0.01) and EQ-VAS score (t =-25.87, P<0.01). We found that pain/discomfort (25.6%) and anxiety/depression (13.7%) were the major HRQOL problems. Locality, age, ethnicity, household income per month, type of occupation, and type of nonprescription medicine purchased were associated with health status of nonprescription medicine customers (F22,5286 = 2.555; Wilks' lambda = 0.979; P< 0.01).

    CONCLUSIONS: The HRQOL of nonprescription medicine customers is lower than that of the general Malaysian population. Lower health status was independently associated with older age, living in rural areas, having low income and education level, and purchasing blood and blood-forming medicines from community pharmacy.

  5. Nasution A, Syed Sulaiman SA, Shafie AA
    Value Health Reg Issues, 2013 May;2(1):43-47.
    PMID: 29702851 DOI: 10.1016/j.vhri.2013.02.009
    OBJECTIVES: This study evaluated the clinical and economic impacts of clinical pharmacy education (CPE) on infection management among patients with chronic kidney disease (CKD) stages 4 and 5 in Haji Adam Malik Hospital, Indonesia.

    METHODS: A quasi-experimental economic evaluation comparing CPE impact on 6-month CKD mortality was conducted on the basis of payer perspective. The experimental group (n = 63) received care by health care providers who were given CPE on drug-related problems and dose adjustment. The control group (n = 80) was based on the historical cohort of patients who received care before the CPE. Measure of clinical outcome applied in this study was number of lives saved/100 patients treated. Cost-effectiveness ratios for CKD stages 4 and 5 patients without CPE and with CPE and incremental cost-effectiveness ratios (ICERs) for CKD stages 4 and 5 patients were analyzed.

    RESULTS: Lives saved (%) in the treatment of CKD without CPE: CKD stage 4, 78.57; CKD stage 5, 57.58. Lives saved (%) in the treatment of CKD with CPE: CKD stage 4, 88.89; CKD stage 5, 65.45. Cost-effectiveness ratios for stage 4 with and without CPEs were Rp3,348,733.27 and Rp3,519,931.009, respectively. Cost-effectiveness ratios for stage 5 with and without CPEs were Rp7,137,874.93 and Rp7,871,822.27, respectively. ICERs were Rp2,045,341.22 for CKD stage 4 and Rp1,767,585.60 for CKD stage 5.

    CONCLUSIONS: Treatment of CKD stages 4 and 5 with CPE was more effective and cost-effective compared with treatment of CKD stages 4 and 5 without CPE. The ICERs indicated that extra costs were required to increase life saved in both stages.

    MeSH terms: Cost-Benefit Analysis; Cyclic N-Oxides; Education, Pharmacy; Health Personnel; Humans; Indonesia; Kidney Failure, Chronic; Control Groups; Renal Insufficiency, Chronic
  6. Lee KKC, Chia Wu DB, Topachevskyi O, Delgleize E, DeAntonio R
    Value Health Reg Issues, 2013 May;2(1):64-74.
    PMID: 29702855 DOI: 10.1016/j.vhri.2013.01.012
    BACKGROUND: Pneumococcal universal vaccination in Hong Kong was introduced in 2009.

    OBJECTIVES: We assessed the health and economic impact of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PCV-10) compared with the current 13-valent pneumococcal conjugate vaccine (PCV-13) recommended for Hong Kong in 2011, providing new elements to be considered by public health authorities in the future decision-making process for pneumococcal vaccines in this country.

    METHODS: An analytical model was used to estimate the annual economic and health outcomes of invasive pneumococcal disease (IPD), community-acquired pneumonia, and acute otitis media (AOM), including nontypeable H. influenzae-related AOM, for a birth cohort in Hong Kong from the payer perspective with a 10-year horizon. Clinical impact including morbidity-mortality, quality-adjusted life-years (QALYs), incremental costs, and cost-effectiveness comparing PCV-10 and PCV-13 were estimated. Probabilistic sensitivity analyses by using alternate scenarios were performed.

    RESULTS: Model projections indicate that PCV-13 and PCV-10 have approximately equivalent impact on the prevention of deaths caused by IPD and pneumonia. PCV-13 is projected to prevent 6 additional cases of IPD, whereas PCV-10 is projected to prevent 13,229 additional AOM cases and 101 additional QALYs. For the base case, PCV-10 vaccination is estimated to save 44.6 million Hong Kong dollars (34.1 million Hong Kong dollars discounted). Sensitivity analysis indicated that PCV-10 would generate more QALYs and save costs as compared with PCV-13.

    CONCLUSIONS: Universal infant vaccination with new available pneumococcal vaccines is expected to generate a significant additional impact on reducing the burden of pneumococcal diseases in Hong Kong. PCV-10 vaccination would be potentially a cost-saving strategy compared with PCV-13 vaccination, generating better cost offsets and higher QALY gains.

    MeSH terms: Cost-Benefit Analysis; Haemophilus influenzae; Hong Kong; Humans; Infant; Otitis Media; Pneumococcal Infections; Pneumonia; Public Health; Vaccination; Vaccines, Conjugate; Quality-Adjusted Life Years; Pneumococcal Vaccines
  7. Maimaiti N, Ahmed Z, Md Isa Z, Ghazi HF, Aljunid S
    Value Health Reg Issues, 2013 09 13;2(2):259-263.
    PMID: 29702874 DOI: 10.1016/j.vhri.2013.07.003
    OBJECTIVE: To measure the clinical burden of invasive pneumococcal disease (IPD) in selected developing countries.

    METHODS: This is an extensive literature review of published articles on IPD in selected developing countries from East Asia, South Asia, Middle East, sub-Saharan Africa, and Latin America. We reviewed all the articles retrieved from the knowledge bases that were published between the years 2000 and 2010.

    RESULTS: After applying the inclusion, exclusion, and quality criteria, the comprehensive review of the literature yielded 10 articles with data for pneumococcal meningitis, septicemia/bacteremia, and pneumonia. These selected articles were from 10 developing countries from five different regions. Out of the 10 selected articles, 8 have a detailed discussion on IPD, one of them has s detailed discussion on bacteremia and meningitis, and another one has discussed pneumococcal bacteremia. Out of these 10 articles, only 5 articles discussed the case-fatality ratio (CFR). In our article review, the incidence of IPD ranged from less than 5/100,000 to 416/100,000 population and the CFR ranged from 12.2% to 80% in the developing countries.

    CONCLUSIONS: The review demonstrated that the clinical burden of IPD was high in the developing countries. The incidence of IPD and CFR varies from region to region and from country to country. The IPD burden was highest in sub-Saharan African countries followed by South Asian countries. The CFR was low in high-income countries than in low-income countries.

    MeSH terms: Africa, Northern; Asia; Developing Countries; Far East; Income; Latin America; Meningitis, Pneumococcal; Middle East; Pneumonia; Poverty; Incidence; Bacteremia; Africa South of the Sahara; Developed Countries; Knowledge Bases
  8. Ma RC, Hu C, Tam CH, Zhang R, Kwan P, Leung TF, et al.
    Diabetologia, 2013 Jun;56(6):1291-305.
    PMID: 23532257 DOI: 10.1007/s00125-013-2874-4
    AIMS/HYPOTHESIS: Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.

    METHODS: We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.

    RESULTS: We identified CDKN2A/B and four novel type 2 diabetes association signals with p 

    MeSH terms: Adult; Aged; China; Chromosomes, Human, Pair 7*; Diabetes Mellitus, Type 2/ethnology; Diabetes Mellitus, Type 2/genetics*; Female; Genetic Markers; Genotype; Hong Kong; Humans; Japan; Male; Middle Aged; Singapore; Genetic Variation; Homeodomain Proteins/genetics*; Genetic Predisposition to Disease*; Asian Continental Ancestry Group; Insulin-Secreting Cells/cytology; Paired Box Transcription Factors/genetics*; Genome-Wide Association Study*
  9. Leow MK, Griva K, Choo R, Wee HL, Thumboo J, Tai ES, et al.
    PLoS ONE, 2013;8(6):e67138.
    PMID: 23826215 DOI: 10.1371/journal.pone.0067138
    BACKGROUND: HRQoL is an important outcome to guide and promote healthcare. Clinical and socioeconomic factors may influence HRQoL according to ethnicity.

    METHODOLOGY: A multiethnic cross-sectional national cohort (N = 7198) of the Singapore general population consisting of Chinese (N = 4873), Malay (N = 1167) and Indian (N = 1158) adults were evaluated using measures of HRQoL (SF-36 version 2), family functioning, health behaviours and clinical/laboratory assessments. Multiple regression analyses were performed to identify determinants of physical and mental HRQoL in the overall population and their potential differential effects by ethnicity. No a priori hypotheses were formulated so all interaction effects were explored.

    PRINCIPAL FINDINGS: HRQoL levels differed between ethnic groups. Chinese respondents had higher physical HRQoL (PCS) than Indian and Malay participants (p<0.001) whereas mental HRQoL (MCS) was higher in Malay relative to Chinese participants (p<0.001). Regressions models explained 17.1% and 14.6% of variance in PCS and MCS respectively with comorbid burden, income and employment being associated with lower HRQoL. Age and family were associated only with MCS. The effects of gender, stroke and musculoskeletal conditions on PCS varied by ethnicity, suggesting non-uniform patterns of association for Chinese, Malay and Indian individuals.

    CONCLUSIONS: Differences in HRQoL levels and determinants of HRQoL among ethnic groups underscore the need to better or differentially target population segments to promote well-being. More work is needed to explore HRQoL and wellness in relation to ethnicity.

    MeSH terms: Adult; Aged; Aged, 80 and over; China/ethnology; Cross-Sectional Studies; Female; Follow-Up Studies; Humans; India/ethnology; Malaysia/ethnology; Male; Middle Aged; Prospective Studies; Quality of Life*; Regression Analysis; Singapore; Socioeconomic Factors; Health Behavior; Young Adult
  10. Al-Amiery AA, Kadhum AAH, Mohamad AB, Junaedi S
    Materials (Basel), 2013 Apr 02;6(4):1420-1431.
    PMID: 28809218 DOI: 10.3390/ma6041420
    2-(1-methyl-4-((E)-(2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-ylidene)-hydrazineecarbothioamide (HCB) was synthesized as a corrosion inhibitor from the reaction of 4-aminoantipyrine, thiosemicarbazide and 2-methylbenzaldehyde. The corrosion inhibitory effects of HCB on mild steel in 1.0 M HCl were investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that HCB inhibited mild steel corrosion in acidic solution and inhibition efficiency increased with an increase in the concentration of the inhibitor. The inhibition efficiency was up to 96.5% at 5.0 mM. Changes in the impedance parameters suggested that HCB adsorbed on the surface of mild steel, leading to the formation of a protective film. The novel corrosion inhibitor synthesized in the present study was characterized using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectral data.
  11. Silakhori M, Naghavi MS, Metselaar HSC, Mahlia TMI, Fauzi H, Mehrali M
    Materials (Basel), 2013 Apr 29;6(5):1608-1620.
    PMID: 28809232 DOI: 10.3390/ma6051608
    Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems.
  12. Nazarpour F, Abdullah DK, Abdullah N, Zamiri R
    Materials (Basel), 2013 May 15;6(5):2059-2073.
    PMID: 28809260 DOI: 10.3390/ma6052059
    e effects of biological pretreatment on the rubberwood (Hevea brasiliensis), was evaluated after cultivation of white rot fungi Ceriporiopsis subvermispora, Trametes versicolor, and a mixed culture of C. subvermispora and T. versicolor. The analysis of chemical compositions indicated that C. subvermispora had greater selectivity for lignin degradation with the highest lignin and hemicellulose loss at 45.06% and 42.08%, respectively, and lowest cellulose loss (9.50%) after 90 days among the tested samples. X-ray analysis showed that pretreated samples had a higher crystallinity than untreated samples. The sample pretreated by C. subvermispora presented the highest crystallinity of all the samples which might be caused by the selective degradation of amorphous components. Fourier transform infrared (FT-IR) spectroscopy demonstrated that the content of lignin and hemicellulose decreased during the biological pretreatment process. A study on hydrolysis of rubberwood treated with C. subvermispora, T. versicolor, and mixed culture for 90 days resulted in an increased sugar yield of about 27.67%, 16.23%, and 14.20%, respectively, as compared with untreated rubberwood (2.88%). The results obtained demonstrate that rubberwood is a potential raw material for industrial applications and white rot fungus C. subevermispora provides an effective method for improving the enzymatic hydrolysis of rubberwood.
  13. Yaakob Z, Bshish A, Ebshish A, Tasirin SM, Alhasan FH
    Materials (Basel), 2013 May 30;6(6):2229-2239.
    PMID: 28809270 DOI: 10.3390/ma6062229
    Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/AlS.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/AlS.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/AlS.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.
  14. Islam MT, Alam MS
    Materials (Basel), 2013 Jan 07;6(1):143-155.
    PMID: 28809299 DOI: 10.3390/ma6010143
    A compact planar meander-bridge high impedance electromagnetic structure (MBHIES) was designed and its bandgap characteristics, mutual coupling reduction abilities were studied and compared in detail. Several parametric analyses were performed to obtain optimized design values and the transmission responses were calculated through the suspended microstrip line and waveguide simulation methods. The achieved bandgap is 2.3 GHz (2.55-4.85 GHz) with -61 dB minimum transmission coefficient level at the center frequency of 3.6 GHz. To see the effectiveness, the proposed design was inserted between a microstrip patch antenna array which operates at 3.8 GHz and whose operating bandwidth falls within the MBHIES bandgap. The surface wave suppression phenomenon was analyzed and simulated results are verified by measuring the fabricated prototypes, both are in good agreement. The configuration reduced the mutual coupling by 20.69 dB in simulation and 19.18 dB in measurement, without affecting the radiation characteristics of the array but increasing the gain slightly.
  15. Shamsuri AA, Daik R
    Materials (Basel), 2013 Feb 22;6(2):682-698.
    PMID: 28809334 DOI: 10.3390/ma6020682
    An ionic liquid, 1-n-butyl-3-methylimidazolium chloride (BmimCl) was blended with urea at 1:1 mole ratio to create a BmimCl/Urea mixture. The agarose/talc composite films containing the BmimCl/Urea mixture were then acquired through a gelation method. The weight ratio of agarose and talc was fixed at 4:1, while the content of BmimCl/Urea was varied from 0 to 10 wt % relative to the overall weight of the composite films. The tensile stress and modulus results showed the optimum BmimCl/Urea content in the composite film lies at 8 wt %. The talc particles are embedded in the agarose matrix and there are no pullouts for the composite films containing BmimCl/Urea as demonstrated by SEM micrographs. The addition of BmimCl/Urea increased the glass transition temperature of the composite films, however, the thermal decomposition temperature decreased drastically. FTIR and FT-Raman spectra indicated the existence of interaction between agarose and talc, which improves their interfacial adhesion. As a conclusion, a BmimCl/Urea mixture can be utilized as a coupling agent for agarose/talc composite films.
  16. Islam MT, Ullah MH, Singh MJ, Faruque MRI
    Materials (Basel), 2013 Jul 31;6(8):3226-3240.
    PMID: 28811432 DOI: 10.3390/ma6083226
    A new metasurface superstrate structure (MSS)-loaded dual band microstrip line-fed small patch antenna is presented in this paper. The proposed antenna was designed on a ceramic-filled bioplastic sandwich substrate with a high dielectric constant. The proposed 7 × 6 element, square-shaped, single-sided MSS significantly improved the bandwidth and gain of the proposed antenna. The proposed MSS incorporated a slotted patch antenna that effectively increased the measured operating bandwidth from 13.3% to 18.8% and from 14.8% to 23.2% in the lower and upper bands, respectively. Moreover, the average gain of the proposed MSS-based antenna was enhanced from 2.12 dBi to 3.02 dBi in the lower band and from 4.10 dBi to 5.28 dBi in the upper band compared to the patch antenna alone. In addition to the bandwidth and gain improvements, more directive radiation characteristics were also observed from the MSS antenna compared to the patch itself. The effects of the MSS elements and the ground plane length on the reflection coefficient of the antenna were analyzed and optimized. The overall performance makes the proposed antenna appropriate for RFID and WLAN applications.
  17. Abdulkareem OA, Abdullah MMAB, Hussin K, Ismail KN, Binhussain M
    Materials (Basel), 2013 Oct 09;6(10):4450-4461.
    PMID: 28788339 DOI: 10.3390/ma6104450
    This paper presents the mechanical and microstructural characteristics of a lightweight aggregate geopolymer concrete (LWAGC) synthesized by the alkali-activation of a fly ash source (FA) before and after being exposed to elevated temperatures, ranging from 100 to 800 °C. The results show that the LWAGC unexposed to the elevated temperatures possesses a good strength-to-weight ratio compared with other LWAGCs available in the published literature. The unexposed LWAGC also shows an excellent strength development versus aging times, up to 365 days. For the exposed LWAGC to the elevated temperatures of 100 to 800 °C, the results illustrate that the concretes gain compressive strength after being exposed to elevated temperatures of 100, 200 and 300 °C. Afterward, the strength of the LWAGC started to deteriorate and decrease after being exposed to elevated temperatures of 400 °C, and up to 800 °C. Based on the mechanical strength results of the exposed LWAGCs to elevated temperatures of 100 °C to 800 °C, the relationship between the exposure temperature and the obtained residual compressive strength is statistically analyzed and achieved. In addition, the microstructure investigation of the unexposed LWAGC shows a good bonding between aggregate and mortar at the interface transition zone (ITZ). However, this bonding is subjected to deterioration as the LWAGC is exposed to elevated temperatures of 400, 600 and 800 °C by increasing the microcrack content and swelling of the unreacted silicates.
  18. Mohammad M, Yaakob Z, Abdullah SRS
    Materials (Basel), 2013 Oct 09;6(10):4462-4478.
    PMID: 28788340 DOI: 10.3390/ma6104462
    Carbon from jatropha seed hull (JC) was prepared to study the adsorption of cadmium ions (Cd(2+)) from aqueous solutions under various experimental conditions. Batch equilibrium methods have been used to study the influences of the initial metal ion concentration (0.5-50 ppm), dosage (0.2-1 g), contact time (0-300 min), pH (2-7), and temperature (26-60 °C) on adsorption behavior. It has been found that the amount of cadmium adsorbed increases with the initial metal ion concentration, temperature, pH, contact time, and amount of adsorbent. A kinetic study proved that the mechanism of Cd(2+) adsorption on JC followed a three steps process, confirmed by an intraparticle diffusion model: rapid adsorption of metal ions, a transition phase, and nearly flat plateau section. The experimental results also showed that the Cd(2+) adsorption process followed pseudo-second-order kinetics. The Langmuir and Freundlich adsorption isotherm models were used to describe the experimental data, with the former exhibiting a better correlation coefficient than the latter (R² = 0.999). The monolayer adsorption capacity of JC has been compared with the capacities of the other reported agriculturally-based adsorbents. It has been clearly demonstrated that this agricultural waste generated by the biofuel industry can be considered a potential low-cost adsorbent for the removal of Cd(2+) from industrial effluents.
  19. Azeez AB, Mohammed KS, Abdullah MMAB, Hussin K, Sandu AV, Razak RA
    Materials (Basel), 2013 Oct 23;6(10):4836-4846.
    PMID: 28788363 DOI: 10.3390/ma6104836
    Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised (137)Cs and ⁶⁰Co radioactive elements with photon energies of 0.662 MeV for (137)Cs and two energy levels of 1.17 and 1.33 MeV for the ⁶⁰Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10(-3) for (137)Cs and 0.92 ± 1.57 × 10(-3) for ⁶⁰Co. Substantial improvement in attenuation performance by 20%-25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%-30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.
  20. Abidin MSZ, Matsumura R, Anisuzzaman M, Park JH, Muta S, Mahmood MR, et al.
    Materials (Basel), 2013 Nov 06;6(11):5047-5057.
    PMID: 28788375 DOI: 10.3390/ma6115047
    We report the crystallization of electrodeposited germanium (Ge) thin films on n-silicon (Si) (100) by rapid melting process. The electrodeposition was carried out in germanium (IV) chloride: propylene glycol (GeCl₄:C₃H₈O₂) electrolyte with constant current of 50 mA for 30 min. The measured Raman spectra and electron backscattering diffraction (EBSD) images show that the as-deposited Ge thin film was amorphous. The crystallization of deposited Ge was achieved by rapid thermal annealing (RTA) at 980 °C for 1 s. The EBSD images confirm that the orientations of the annealed Ge are similar to that of the Si substrate. The highly intense peak of Raman spectra at 300 cm(-1) corresponding to Ge-Ge vibration mode was observed, indicating good crystal quality of Ge. An additional sub peak near to 390 cm(-1) corresponding to the Si-Ge vibration mode was also observed, indicating the Ge-Si mixing at Ge/Si interface. Auger electron spectroscopy (AES) reveals that the intermixing depth was around 60 nm. The calculated Si fraction from Raman spectra was found to be in good agreement with the value estimated from Ge-Si equilibrium phase diagram. The proposed technique is expected to be an effective way to crystallize Ge films for various device applications as well as to create strain at the Ge-Si interface for enhancement of mobility.
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