Browse publications by year: 2015

  1. Zyoud SH, Al-Jabi SW, Sweileh WM, Arandi DA, Dabeek SA, Esawi HH, et al.
    J Clin Transl Endocrinol, 2015 Jun;2(2):66-71.
    PMID: 29159112 DOI: 10.1016/j.jcte.2015.03.002
    Objectives: The aims of the current study were to assess the association between health-related quality of life (HRQoL) and treatment satisfaction in a sample of diabetic patients from Palestine, and to determine the influence of socio-demographic and clinical factors on HRQoL.

    Methods: It was a cross-sectional study performed during the period June 2013 to October 2013. The Arabic version of Treatment Satisfaction Questionnaire for Medication (TSQM 1.4) was used to assess treatment satisfaction, and the Arabic version of European Quality of Life scale (EQ-5D-5L) was used to assess HRQoL. Multiple linear regression was used to estimate which variables were the most important related to HRQoL.

    Results: A total of 385 diabetic patients were included. There were modest positive correlations between the total score on the Overall Satisfaction domain and EQ-5D-5L (r = 0.14; p = 0.005). After adjusting multiple covariates by multiple linear regression, the association between the Overall Satisfaction and HRQoL was not statistically significant (p = 0.075); (R = 0.495; adjusted R(2) = 0.245; F = 10.3; df = 12; p 

  2. Sirkhazi M, Sarriff A, Aziz NA, Almana F, Arafat O, Shorman M
    World J Oncol, 2015 Feb;6(1):283-291.
    PMID: 29147417 DOI: 10.14740/wjon867w
    Background: The objective of this study was to evaluate the outcomes, mortality and toxicity associated with piperacillin-tazobactam (PT) and the addition of vancomycin (VM) to the empirical treatment of febrile neutropenic cancer patients.

    Method: A retrospective study on adult febrile neutropenic patients who were admitted between September 2008 and May 2013 with solid tumor malignancies was conducted at King Fahad Specialist Hospital Dammam, Saudi Arabia.

    Results: Out of 86 febrile neutropenic patients, 60 patients were treated with PT group and 26 patients were with PT + VM group. The two groups were comparable in terms of outcome, mortality, nephrotoxicities and hepatotoxicities. The median duration of neutropenia in PT treatment group was 4 days (range 1 - 10) in the female and 7 days (range 1 - 13) in males while in PT + VM 6 days (range 1 - 5) in female and 7.5 days (range 1 - 6) in male with significance P = 0.007. There was no significant difference in terms of duration of fever and length of stay between the two treatment groups. There were no deaths reported during treatment in both groups. In PT, the microbial eradication was 27/40 (67.5%) patients (14/27 (51.9%) of female and 13/27 (48.1%) of male)), whereas it was 13/40 (32.5%) patients (9/13 (69.2%) of female and 4/13 (30.8%) of male)) in PT + VM group. Overall, there was no significant difference in terms of microbiological eradication between the two groups (OR: 1.22; 95% CI: 0.486 - 3.072; X(2) stat: 0.182; P = 0.67). Response to therapy in clinically defined infections was higher 16/23 (69.56%) in PT treatment group than 7/23 (30.44%) in PT + VM group. But there was no significant difference between the two treatment groups in terms of clinically defined infections (OR: 1.013; 95% CI: 0.359 - 2.862; X(2) stat: 0.001; P = 0.98). There was no significant difference in renal and liver functions between the two groups in terms of serum creatinine level and clearance, alkaline phosphate and alanine tranferase and gama glutamyl tranferase. The most commonly isolated organisms were Escherichais coli (eighteen isolates), Staphylococcus aureus (seven isolates), Streptococcus spp (six isolates) and Klebsiella pneumonia (four isolates). The overall success rate was similar in both treatment arms and treatment was well tolerated, with no severe adverse reactions reported.

    Conclusion: Although the addition of VM might provide an additional value for coverage of gram-positive pathogens. This study demonstrates that there was no significant difference in terms of response rate in both treatment groups, which could be due to the low local methicillin-resistant Staphylococcus aureus (MRSA) rates and other resistant gram-positive organisms at our institution, stressing the importance of local antibiograms in developing empirical neutropenic fever protocols.

  3. Alvin LW, Gee SH, Hong HH, Christopher CW, Henry HS, Weber LK, et al.
    J Robot Surg, 2015 Sep;9(3):201-9.
    PMID: 26531200 DOI: 10.1007/s11701-015-0516-1
    This study evaluates the oncological outcomes of RARP in a multiracial Asian population from a single institution. All suitable patients from 1st January 2003-30th June 2013 were identified from a prospectively maintained cancer registry. Peri-operative and oncological outcomes were analysed. Significance was defined as p < 0.05. There were n = 725 patients identified with a mean follow-up duration 28 months. The mean operative time, EBL and LOS were 186 min, 215 ml and 3 days, respectively. The pathological stage was pT2 in 68.6% (n = 497/725), pT3 in 31.3% (n = 227/725) and n = 1 patient with pT4 disease. The pathological Gleason scores (GS) were 6 in 27.9% (n = 202/725), GS 7 in 63.6% (n = 461/725) and GS ≥ 8 in 8.0 % (n = 58/725). The node positivity rate was 5.8% (n = 21/360). The positive margin rates were 31.0% (n = 154/497) and 70.9% (n = 161/227) for pT2 and pT3, respectively, and decreasing PSM rates are observed with surgical maturity. The biochemical recurrence rates were 9.7% (n = 48/497) and 34.2% (n = 78/228) for pT2 and pT3/T4, respectively. On multivariate analysis, independent predictors of BCR were pathological T stage and pathological Gleason score. Post-operatively, 78.5% (n = 569/725) of patients had no complications and 17.7% (n = 128/725) had minor (Clavien grade I-II) complications. This series, representing the largest from Southeast Asia, suggests that RARP can be a safe and oncologically feasible treatment for localised prostate cancer in an institution with moderate workload.
    MeSH terms: Adult; Aged; China; Humans; India; Malaysia; Male; Middle Aged; Postoperative Complications; Prostatic Neoplasms/surgery*; Treatment Outcome; Asian Continental Ancestry Group
  4. Khan NN, Yahya B, Abu Bakar AK, Ho RC
    BJPsych Int, 2015 May;12(2):40-42.
    PMID: 29093848
    The Malaysian Mental Health Act 2001 did not come into effect until the Mental Health Regulations 2010 came into force. The Act provides a framework for the delivery of comprehensive care, treatment, control, protection and rehabilitation of those with mental disorders. The Act governs the establishment of private and government psychiatric hospitals, psychiatric nursing homes and community mental health centres. This paper outlines the provisions of the Act and the Regulations.
    MeSH terms: Mental Disorders; Community Mental Health Centers; Comprehensive Health Care; Government; Hospitals, Psychiatric; Humans; Mental Health; Nursing Homes; Psychiatric Nursing
  5. Ho RC, Ho CS, Khan N, Kua EH
    BJPsych Int, 2015 May;12(2):42-44.
    PMID: 29093849
    This article summarises the development of mental health legislation in Singapore in three distinctive periods: pre-1965; 1965-2007 and 2007 onwards. It highlights the origin of mental health legislation and the relationship between mental health services and legislation in Singapore. The Mental Health (Care and Treatment) Act 2008 and Mental Capacity Act 2008 are described in detail.
    MeSH terms: Commitment of Mentally Ill; Humans; Mental Health; Mental Health Services; Singapore
  6. Othman Z, Zakaria R, Hussain NHN, Hassan A, Shafin N, Al-Rahbi B, et al.
    Med Sci (Basel), 2015 Apr 09;3(2):3-15.
    PMID: 29083387 DOI: 10.3390/medsci3020003
    The composition and physicochemical properties of honey are variable depending on its floral source and often named according to the geographical location. The potential medicinal benefits of Tualang honey, a multifloral jungle honey found in Malaysia, have recently been attracting attention because of its reported beneficial effects in various diseases. This paper reviews the effects of honey, particularly Tualang honey, on learning and memory. Information regarding the effects of Tualang honey on learning and memory in human as well as animal models is gleaned to hypothesize its underlying mechanisms. These studies show that Tualang honey improves morphology of memory-related brain areas, reduces brain oxidative stress, increases brain-derived neurotrophic factor (BDNF) and acetylcholine (ACh) concentrations, and reduces acetylcholinesterase (AChE) in the brain homogenates. Its anti-inflammatory roles in reducing inflammatory trigger and microglial activation have yet to be investigated. It is hypothesized that the improvement in learning and memory following Tualang honey supplementation is due to the significant improvement in brain morphology and enhancement of brain cholinergic system secondary to reduction in brain oxidative damage and/or upregulation of BDNF concentration. Further studies are imperative to elucidate the molecular mechanism of actions.
  7. Fiedler P, Pedrosa P, Griebel S, Fonseca C, Vaz F, Supriyanto E, et al.
    Brain Topogr, 2015 Sep;28(5):647-656.
    PMID: 25998854 DOI: 10.1007/s10548-015-0435-5
    Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44% of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition.
    MeSH terms: Adult; Electrodes; Electroencephalography/instrumentation*; Electroencephalography/methods; Equipment Design/instrumentation*; Evoked Potentials; Female; Humans; Male; Reproducibility of Results; Electric Impedance
  8. Liong SL, Mohidin N, Tan BW, Ali BM
    Taiwan J Ophthalmol, 2015;5(4):164-168.
    PMID: 29018692 DOI: 10.1016/j.tjo.2015.07.006
    BACKGROUND/PURPOSE: The effect of orthokeratology (OK) on low myopia is well known, but there are a few reports on its effect on high myopia. In this study, the parametric changes in high and low myopia as results of wearing OK lenses for a period of 6 months have been analyzed.
    METHODS: Records of schoolchildren (age 7-17 years) undergoing OK treatment from an optometry clinic were retrospectively reviewed. Data involving refractive errors, uncorrected visual acuity, and corneal curvatures at baseline and after 1 day, 1 week, 1 month, 3 months, and 6 months of OK treatment from 25 patients who fulfilled the inclusion criteria were examined. For the analysis, the participants were arbitrarily divided into two groups comprising high myopia (< -6.00 D) and low to moderate myopia (from -1.00 D to -6.00 D).
    RESULTS: Significant reductions of refractive error, improvement in visual acuity, and corneal-curvature flattening were found in all participants after 6 months of OK lens wear compared to the baseline. No significant changes were found in corneal toricity in both high and low to moderate myopic groups. Almost all of these occurred after one night of lens wear in both the high- and low-myopia groups.
    CONCLUSION: The OK lens wear significantly reduced the refractive error and corneal curvature that results in the improvement in visual acuity in both high- and low-myopia groups, and the reduction seemed to occur nearly at the same time despite the difference in initial myopic power. High myopes with refractive power up to -8.25 D would benefit significantly from OK lenses.
    Study site: Optometry clinic, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
    MeSH terms: Ambulatory Care Facilities; Cornea; Humans; Malaysia; Myopia; Optometry; Refractive Errors; Retrospective Studies; Visual Acuity
  9. Elyasi Gorji Z, Amiri-Yekta A, Gourabi H, Hassani S, Fatemi N, Zerehdaran S, et al.
    Iran J Biotechnol, 2015 Jun;13(2):10-17.
    PMID: 28959285 DOI: 10.15171/ijb.1004
    BACKGROUND: Follicle stimulating hormone (FSH) plays an essential role in reproductive physiology and follicular development.

    OBJECTIVE: A new variant of the equine fsh (efsh) gene was cloned, sequenced, and expressed in Pichia pastoris (P. pastoris) GS115 yeast expression system.

    MATERIALS AND METHODS: The full-length cDNAs of the efshα and efshβ chains were amplified by reverse transcription polymerase chain reaction (RT-PCR) using the total RNA isolated from an Iranian Turkmen-thoroughbred horse's anterior pituitary gland. The amplified efsh chains were cloned into the pPIC9 vector and transferred into P. pastoris. The secretion of recombined eFSH using P. pastoris expression system was confirmed by Western blotting and immunoprecipitation (IP) methods.

    RESULTS: The DNA sequence of the efshβ chain accession number JX861871, predicted two putative differential nucleotide arrays, both of which are located in the 3'UTR. Western blotting showed a molecular mass of 13 and 18 kDa for eFSHα and eFSHβ subunits, respectively. The expression of desired protein was confirmed by protein G immunoprecipitation kit.

    CONCLUSIONS: eFSH successfully expressed in P. pastoris. These findings lay a foundation to improve ovulation and embryo recovery rates as well as the efficiency of total embryo-transfer process in mares.

    MeSH terms: Animals; Base Sequence; Embryo Transfer; Female; Follicle Stimulating Hormone; Horses; Iran; Nucleotides; Ovulation; Pituitary Gland, Anterior; Saccharomyces cerevisiae; Bodily Secretions; Blotting, Western; DNA, Complementary; Reverse Transcriptase Polymerase Chain Reaction; 3' Untranslated Regions; Immunoprecipitation; Reverse Transcription
  10. Elgadir MA, Uddin MS, Ferdosh S, Adam A, Chowdhury AJK, Sarker MZI
    J Food Drug Anal, 2015 Dec;23(4):619-629.
    PMID: 28911477 DOI: 10.1016/j.jfda.2014.10.008
    Chitosan is a promising biopolymer for drug delivery systems. Because of its beneficial properties, chitosan is widely used in biomedical and pharmaceutical fields. In this review, we summarize the physicochemical and drug delivery properties of chitosan, selected studies on utilization of chitosan and chitosan-based nanoparticle composites in various drug delivery systems, and selected studies on the application of chitosan films in both drug delivery and wound healing. Chitosan is considered the most important polysaccharide for various drug delivery purposes because of its cationic character and primary amino groups, which are responsible for its many properties such as mucoadhesion, controlled drug release, transfection, in situ gelation, and efflux pump inhibitory properties and permeation enhancement. This review can enhance our understanding of drug delivery systems particularly in cases where chitosan drug-loaded nanoparticles are applied.
  11. Javadi N, Abas F, Mediani A, Abd Hamid A, Khatib A, Simoh S, et al.
    J Food Drug Anal, 2015 Sep;23(3):433-441.
    PMID: 28911700 DOI: 10.1016/j.jfda.2015.01.005
    Cosmos caudatus, which is a commonly consumed vegetable in Malaysia, is locally known as "Ulam Raja". It is a local Malaysian herb traditionally used as a food and medicinal herb to treat several maladies. Its bioactive or nutritional constituents consist of a wide range of metabolites, including glucosinolates, phenolics, amino acids, organic acids, and sugars. However, many of these metabolites are not stable and easily degraded or modified during storage. In order to investigate the metabolomics changes occurring during post-harvest storage, C. caudatus samples were subjected to seven different storage times (0 hours, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, and 12 hours) at room temperature. As the model experiment, the metabolites identified by gas chromatography-mass spectrometry (GC-MS) were correlated with α-glucosidase inhibitory activity analyzed with multivariate data analysis (MVDA) to find out the variation among samples and metabolites contributing to the activity. Orthogonal partial least squares (OPLS) analysis was applied to investigate the metabolomics changes. A profound chemical alteration, both in primary and secondary metabolites, was observed. The α-tocopherol, catechin, cyclohexen-1-carboxylic acid, benzoic acid, myo-inositol, stigmasterol, and lycopene compounds were found to be the discriminating metabolites at early storage; however, sugars such as sucrose, α-d-galactopyranose, and turanose were detected, which was attributed to the discriminating metabolites for late storage. The result shows that the MVDA method is a promising technique to identify biomarker compounds relative to storage at different times.
  12. Safri Zainal Abidin, Raizulnasuha Abdul Rashid, Muhammad Afiq Khairil Anuar, Wan Nordiana A. Abd Rahman
    MyJurnal
    The purpose of this study is to determine the technetium-99m pertechnetate (99mTcO4) intercellular uptake by different types of cell lines. HeLa, human fetal
    osteoblast (hFOB), glial and glioma cell lines grown in 6-wells culture plates were incubated with 99mTcO4 of activity of 200, 400, 600. 800 and 1000
    pCi for 30 minutes at 3T°C and 5% ( '< - humidified atmosphere. After incubation, the cells were washed 3 times with phosphate buffer saline to remove the
    extracellular traces of 99mTcO4. Measurements of the intercellular Q9mTcOjt radioactivity were performed using single head gamma
    camera and the percentage uptake of the yUwTcGpinto the cells was calculated. The intercellular uptake
    0fyUmTcO_( was found to be inversely correlate to the radioactivity HeLa cell shows the highest uptake
    followed by hFOB, glial and glioma cell lines. Comparison of uptake between normal and cancer cells
    present indistinguishable results. The findings of this study suggest that the intercellular uptake of
    yymTcOjt is highly dependent on the type of cells despite no significant different of uptake was found
    between normal and cancer cell lines. The level of radioactivity is also an important determinant
    factor that influence the uptake ofyUmTcG) into the cells. This study will be the first precedent toward
    understanding the cellular characteristic and pharmacokinetic of non-invasive imaging tracer for
    future molecular imaging and therapy.
  13. Lam CSP
    ESC Heart Fail, 2015 Jun;2(2):46-49.
    PMID: 28834655 DOI: 10.1002/ehf2.12036
    Southeast Asia is home to a growing population of >600 million people, the majority younger than 65 years, but among whom, rapid epidemiological transition has led to high rates of premature death from non-communicable diseases (chiefly cardiovascular disease) (up to 28% in the Philippines vs. 12% in UK). There is a strikingly high prevalence of stage A heart failure (HF) risk factors in Southeast Asia, particularly hypertension (>24% in Cambodia and Laos vs. 13-15% in UK and USA), tobacco smoking (>36% in Indonesia), physical inactivity (>50% in Malaysia) and raised blood glucose (10-11% in Brunei, Malaysia, Singapore and Thailand) in spite of a low prevalence of overweight/obesity (21-26% in Southeast Asia vs. 67-70% in UK and USA). Accordingly, the prevalence of symptomatic HF appears to be higher in Southeast Asian countries compared with the rest of the world. Epidemiologic trends in Singapore showed a sharp 38% increase in age-adjusted HF hospitalizations (from 85.4 per 10 000 in 1991 to 110.3 per 10 000 in 1998) with notable ethnic differences (hospitalization rates ~35% higher in Malays and Indians vs. Chinese; mortality 3.5 times higher in Malays vs. Indians and Chinese). Furthermore, Southeast Asian patients present with acute HF at a younger age (54 years) compared with USA patients (75 years) but have more severe clinical features, higher rates of mechanical ventilation, longer lengths of stay (6 vs. 4.2 days) and higher in-hospital mortality (4.8 vs. 3.0%). Finally, there is under-usage of guideline-recommended HF medical therapies (prescribed in 31-63% of patients upon discharge) and device therapies in Southeast Asia. Large gaps in knowledge that need to be addressed in Southeast Asia include the prevalence of HF with preserved ejection fraction, clinical outcomes, barriers to recommended therapies and their cost-effectiveness, as well as possible ethnicity-specific pathophysiologic mechanisms.
  14. Shukri AA, Darain KMU, Jumaat MZ
    Materials (Basel), 2015 Jul 08;8(7):4131-4146.
    PMID: 28793429 DOI: 10.3390/ma8074131
    Tension stiffening is a characteristic behavior of reinforced concrete (RC) beams which is directly affected by the bond-slip property of steel bar and concrete interfaces. A beam strengthened with a near-surface mounted (NSM) technique would be even more affected by tension stiffening, as the NSM reinforcement also possess a bond-slip property. Yet assessing how much the tension stiffening of NSM contributes to the behavior of RC beams is difficult due to the fact that bond-slip effects cannot be directly incorporated into a strain-based moment-curvature analysis. As such, the tension stiffening is typically incorporated through various empirical formulations, which can require a great deal of testing and calibrations to be done. In this paper a relatively new method, which can be called the mechanics-based segmental approach, is used to directly simulate the tension stiffening effect of NSM reinforcements on RC beams, without the need for empirical formulations to indirectly simulate the tension stiffening. Analysis shows that the tension stiffening of NSM fiber reinforced polymer (FRP) contributes a significant portion to the stiffness and strength of the strengthened RC beam not only during serviceability, but at all load levels.
    MeSH terms: Calibration; Carmustine; Dietary Fiber; Drug Compounding; Polymers; Steel; Laxatives
  15. Islam MM, Islam MT, Faruque MRI, Samsuzzaman M, Misran N, Arshad H
    Materials (Basel), 2015 Jul 23;8(8):4631-4651.
    PMID: 28793461 DOI: 10.3390/ma8084631
    The design of a compact metamaterial ultra-wideband (UWB) antenna with a goal towards application in microwave imaging systems for detecting unwanted cells in human tissue, such as in cases of breast cancer, heart failure and brain stroke detection is proposed. This proposed UWB antenna is made of four metamaterial unit cells, where each cell is an integration of a modified split ring resonator (SRR), capacitive loaded strip (CLS) and wire, to attain a design layout that simultaneously exhibits both a negative magnetic permeability and a negative electrical permittivity. This design results in an astonishing negative refractive index that enables amplification of the radiated power of this reported antenna, and therefore, high antenna performance. A low-cost FR4 substrate material is used to design and print this reported antenna, and has the following characteristics: thickness of 1.6 mm, relative permeability of one, relative permittivity of 4.60 and loss tangent of 0.02. The overall antenna size is 19.36 mm × 27.72 mm × 1.6 mm where the electrical dimension is 0.20 λ × 0.28 λ × 0.016 λ at the 3.05 GHz lower frequency band. Voltage Standing Wave Ratio (VSWR) measurements have illustrated that this antenna exhibits an impedance bandwidth from 3.05 GHz to more than 15 GHz for VSWR < 2 with an average gain of 4.38 dBi throughout the operating frequency band. The simulations (both HFSS and computer simulation technology (CST)) and the measurements are in high agreement. A high correlation factor and the capability of detecting tumour simulants confirm that this reported UWB antenna can be used as an imaging sensor.
    MeSH terms: Brain; Breast Neoplasms; Computer Simulation; Electricity; Goals; Heart Failure; Humans; Microwaves; Permeability; Refractometry; Electric Impedance; Stroke
  16. Islam SS, Faruque MRI, Islam MT
    Materials (Basel), 2015 Jul 29;8(8):4790-4804.
    PMID: 28793472 DOI: 10.3390/ma8084790
    The paper reveals the design of a unit cell of a metamaterial that shows more than 2 GHz wideband near zero refractive index (NZRI) property in the C-band region of microwave spectra. The two arms of the unit cell were splitted in such a way that forms a near-pi-shape structure on epoxy resin fiber (FR-4) substrate material. The reflection and transmission characteristics of the unit cell were achieved by utilizing finite integration technique based simulation software. Measured results were presented, which complied well with simulated results. The unit cell was then applied to build a single layer rectangular-shaped cloak that operates in the C-band region where a metal cylinder was perfectly hidden electromagnetically by reducing the scattering width below zero. Moreover, the unit cell shows NZRI property there. The experimental result for the cloak operation was presented in terms of S-parameters as well. In addition, the same metamaterial shell was also adopted for designing an eye-shaped and triangular-shaped cloak structure to cloak the same object, and cloaking operation is achieved in the C-band, as well with slightly better cloaking performance. The novel design, NZRI property, and single layer C-band cloaking operation has made the design a promising one in the electromagnetic paradigm.
    MeSH terms: Dietary Fiber; Epoxy Resins; Metals; Microwaves; Refractometry; Software; Laxatives; Electromagnetic Phenomena
  17. Alam T, Faruque MRI, Islam MT
    Materials (Basel), 2015 Jul 29;8(8):4817-4828.
    PMID: 28793474 DOI: 10.3390/ma8084817
    A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a -10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN) frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane.
    MeSH terms: Electricity; Local Area Networks; Electric Impedance; Physical Phenomena; Electromagnetic Phenomena; Mobile Applications
  18. Lee WH, Lai CW, Hamid SBA
    Materials (Basel), 2015 Aug 28;8(9):5702-5714.
    PMID: 28793530 DOI: 10.3390/ma8095270
    WO₃-decorated TiO₂ nanotube arrays were successfully synthesized using an in situ anodization method in ethylene glycol electrolyte with dissolved H₂O₂ and ammonium fluoride in amounts ranging from 0 to 0.5 wt %. Anodization was carried out at a voltage of 40 V for a duration of 60 min. By using the less stable tungsten as the cathode material instead of the conventionally used platinum electrode, tungsten will form dissolved ions (W(6+)) in the electrolyte which will then move toward the titanium foil and form a coherent deposit on the titanium foil. The fluoride ion content was controlled to determine the optimum chemical dissolution rate of TiO₂ during anodization to produce a uniform nanotubular structure of TiO₂ film. Nanotube arrays were then characterized using FESEM, EDAX, XRD, as well as Raman spectroscopy. Based on the FESEM images obtained, nanotube arrays with an average pore diameter of up to 65 nm and a length of 1.8 µm were produced. The tungsten element in the samples was confirmed by EDAX results which showed varying tungsten content from 0.22 to 2.30 at%. XRD and Raman results showed the anatase phase of TiO₂ after calcination at 400 °C for 4 h in air atmosphere. The mercury removal efficiency of the nanotube arrays was investigated by photoirradiating samples dipped in mercury chloride solution with TUV (Tube ultraviolet) 96W UV-B Germicidal light. The nanotubes with the highest aspect ratio (15.9) and geometric surface area factor (92.0) exhibited the best mercury removal performance due to a larger active surface area, which enables more Hg(2+) to adsorb onto the catalyst surface to undergo reduction to Hg⁰. The incorporation of WO₃ species onto TiO₂ nanotubes also improved the mercury removal performance due to improved charge separation and decreased charge carrier recombination because of the charge transfer from the conduction band of TiO₂ to the conduction band of WO₃.
    MeSH terms: Quaternary Ammonium Compounds; Electrodes; Fluorides; Hydrogen Peroxide; Mercuric Chloride; Mercury; Platinum; Solubility; Spectrum Analysis, Raman; Titanium; Tungsten; Ethylene Glycol; Nanotubes
  19. Kanadasan J, Fauzi AFA, Razak HA, Selliah P, Subramaniam V, Yusoff S
    Materials (Basel), 2015 Sep 22;8(9):6508-6530.
    PMID: 28793579 DOI: 10.3390/ma8095319
    The agricultural industry in Malaysia has grown rapidly over the years. Palm oil clinker (POC) is a byproduct obtained from the palm oil industry. Its lightweight properties allows for its utilization as an aggregate, while in powder form as a filler material in concrete. POC specimens obtained throughout each state in Malaysia were investigated to evaluate the physical, chemical, and microstructure characteristics. Variations between each state were determined and their possible contributory factors were assessed. POC were incorporated as a replacement material for aggregates and their engineering characteristics were ascertained. Almost 7% of density was reduced with the introduction of POC as aggregates. A sustainability assessment was made through greenhouse gas emission (GHG) and cost factor analyses to determine the contribution of the addition of POC to the construction industry. Addition of POC helps to lower the GHG emission by 9.6% compared to control specimens. By channeling this waste into the construction industry, an efficient waste-management system can be promoted; thus, creating a cleaner environment. This study is also expected to offer some guides and directions for upcoming research works on the incorporation of POC.
    MeSH terms: Agriculture; Engineering; Factor Analysis, Statistical; Malaysia; Waste Management; Construction Industry
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