Displaying publications 41 - 60 of 176 in total

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  1. The prevalence and intensity of Amblyomma javanense infestation on Malayan pangolins (Manis javanica Desmarest) from Peninsular Malaysia
    Hassan M, Sulaiman MH, Lian CJ
    Acta Trop, 2013 May;126(2):142-5.
    PMID: 23416121 DOI: 10.1016/j.actatropica.2013.02.001
    A parasitological survey of 16 pangolins, confiscated from the Department of Wildlife and Nature Park Peninsular Malaysia (DWNP) at Kelantan and Pulau Pinang, Malaysia was conducted in 2011. Amblyomma javanense (family: Ixodidae) was the only ectoparasite found on the pangolins. The prevalence, intensity and life cycle of A. javanense were observed together with the respective pangolins' age and sex. It was found that 68.8% of the pangolins were infected, and significant difference, χ(2)(1, N=16)=4.02, p=0.05 were observed with males higher in infestation (88.9%) as compared to the females (42.9%). However, the mean intensity was higher on females (72) as compared to males (31.6). In addition, significant difference, χ(2) (2, N=16)=6.73, p=0.05 was recorded between adults and juveniles with juveniles found to be 100% infected as compared to adult (63.6%). Nevertheless, the mean intensity was slightly higher on adults (47) than juveniles (35). Adult ticks were found in higher numbers as compared to the nymph and larvae with number of male ticks higher (236) as compared to the females (53). Similarly, a high significant difference χ(2)(2, N=469)=203.47, p=0.05 was recorded in the composition of the tick's life stages with a higher number of adult ticks (61.6%) followed by nymph (30.3%) and larvae (8.1%). As such, the results of this study revealed a picture of the A. javanense life cycle which is related to the age and gender of the Malayan Pangolin.
  2. Salivary trace elements in relation to dental caries in a group of multi-ethnic schoolchildren in Shah Alam, Malaysia
    Hussein AS, Ghasheer HF, Ramli NM, Schroth RJ, Abu-Hassan MI
    Eur J Paediatr Dent, 2013 Jun;14(2):113-8.
    PMID: 23758460
    AIM: To assess the salivary levels of Copper (Cu), Zinc (Zn), Manganese (Mn) and Iron (Fe) obtained from children of different ethnic backgrounds in Shah Alam, Malaysia and investigate the possible relationships with caries.

    MATERIALS AND METHODS: One hundred and twenty primary school children were included. They were divided into caries and caries-free groups. Unstimulated whole saliva was collected from each participant using spitting method. The salivary elements were measured using an Atomic Absorption Spectrophotometer. Descriptive statistics, bivariate and Pearson's correlation analysis were performed.

    RESULTS: Salivary Cu and Zn levels were significantly higher in children with dental caries compared to those caries-free (p < 0.05). Moreover, these elements had a positive correlation with dental caries (Cu: r=0.698, p<0.001; Zn: r=0.181, p<0.05). No significant variations in Mn and Fe were observed between caries and caries-free group (p>0.05). Additionally, there were significant differences in salivary Zn and Fe among different age groups (p<0.05) and highly significant differences in salivary Cu, Mn and Fe among different ethnic groups (p<0.001). However, all elements exhibited no significant differences between males and females.

    CONCLUSION: The salivary Cu and Zn levels showed significant differences between caries and caries-free groups. The findings also revealed significant variations in the levels of salivary Cu, Mn and Fe among different ethnic groups and salivary Zn and Fe among different age groups.

  3. Crude cellulase from oil palm empty fruit bunch by Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2 for fermentable sugars production
    Ibrahim MF, Razak MN, Phang LY, Hassan MA, Abd-Aziz S
    Appl Biochem Biotechnol, 2013 Jul;170(6):1320-35.
    PMID: 23666614 DOI: 10.1007/s12010-013-0275-2
    Cellulase is an enzyme that converts the polymer structure of polysaccharides into fermentable sugars. The high market demand for this enzyme together with the variety of applications in the industry has brought the research on cellulase into focus. In this study, crude cellulase was produced from oil palm empty fruit bunch (OPEFB) pretreated with 2% NaOH with autoclave, which was composed of 59.7% cellulose, 21.6% hemicellulose, and 12.3% lignin using Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2. Approximately 0.8 U/ml of FPase, 24.7 U/ml of CMCase and 5.0 U/ml of β-glucosidase were produced by T. asperellum UPM1 at a temperature of 35 °C and at an initial pH of 7.0. A 1.7 U/ml of FPase, 24.2 U/ml of CMCase, and 1.1 U/ml of β-glucosidase were produced by A. fumigatus UPM2 at a temperature of 45 °C and at initial pH of 6.0. The crude cellulase was best produced at 1% of substrate concentration for both T. asperellum UPM1 and A. fumigatus UPM2. The hydrolysis percentage of pretreated OPEFB using 5% of crude cellulase concentration from T. asperellum UPM1 and A. fumigatus UPM2 were 3.33% and 19.11%, with the reducing sugars concentration of 1.47 and 8.63 g/l, respectively.
  4. Nanocrystalline forsterite for biomedical applications: synthesis, microstructure and mechanical properties
    Ramesh S, Yaghoubi A, Lee KY, Chin KM, Purbolaksono J, Hamdi M, et al.
    J Mech Behav Biomed Mater, 2013 Sep;25:63-9.
    PMID: 23726923 DOI: 10.1016/j.jmbbm.2013.05.008
    Forsterite (Mg2SiO4) because of its exceptionally high fracture toughness which is close to that of cortical bones has been nominated as a possible successor to calcium phosphate bioceramics. Recent in vitro studies also suggest that forsterite possesses good bioactivity and promotes osteoblast proliferation as well as adhesion. However studies on preparation and sinterability of nanocrystalline forsterite remain scarce. In this work, we use a solid-state reaction with magnesium oxide (MgO) and talc (Mg3Si4(OH)2) as the starting precursors to synthesize forsterite. A systematic investigation was carried out to elucidate the effect of preparatory procedures including heat treatment, mixing methods and sintering temperature on development of microstructures as well as the mechanical properties of the sintered forsterite body.
  5. Fulltext Do Professional Practices among Malaysian Private Healthcare Providers Differ? A Comparative Study using Simulated Patients
    Alabid AH, Ibrahim MI, Hassali MA
    J Clin Diagn Res, 2013 Dec;7(12):2912-6.
    PMID: 24551673 DOI: 10.7860/JCDR/2013/6198.3789
    BACKGROUND: Malaysia, a South East Asian country, legally permits general medical practitioners in private clinics to dispense medicines. This possibly can dilute the pharmacist role in the provision of healthcare and pharmaceutical care and deprive patients to benefit from these services.

    OBJECTIVE: This study explored, assessed and compared the current status of medicines labeling, patient's counseling, and symptomatic diagnosis by general practitioners and community pharmacists.

    MATERIAL AND METHODS: This study used trained Simulated Patients (SP), who participated in a scenario of common cold symptoms at private clinics and community pharmacies. SPs explored medication labeling, patients counseling and symptomatic diagnosis undertaken by general practitioners and community pharmacists. Later, study authors assessed and compared these practices. The study was conducted during June 2011 in Penang, Malaysia.

    RESULTS: The study used descriptive statistics and Fisher-exact test to analyze data. Regarding patients counseling standard, among 100 visits by simulated patients, 64 (64%) from community pharmacists provided information about the medicine name, its indication, dosage and route of administration versus 17 (42.5%) general practitioners during 40 visits (p=0.024). Concerning adherence to labeling standard, for instance, only in one pharmacy visit, (1%) the pharmacist wrote the name of the patient on the medication label versus in 32 (80%) of doctors' visits, the doctors adhered to this labeling standard (p<0.001). In all doctors' visits (n=40, 100%), SPs were asked about symptoms, whereas in 87 (87%) CPs' visits, pharmacists fulfilled this counseling standard (p=0.02).

    CONCLUSION: Although pharmacists showed less compliance to medicine labeling and symptomatic diagnosis compared to doctors, their counseling of patients was better. Separation will definitely contribute to more concentration of each provider on his/her roles and improve and direct the experiences and skills towards being more patient oriented.

  6. Fulltext Recovery of glucose from residual starch of sago hampas for bioethanol production
    Awg-Adeni DS, Bujang KB, Hassan MA, Abd-Aziz S
    Biomed Res Int, 2013;2013:935852.
    PMID: 23509813 DOI: 10.1155/2013/935852
    Lower concentration of glucose was often obtained from enzymatic hydrolysis process of agricultural residue due to complexity of the biomass structure and properties. High substrate load feed into the hydrolysis system might solve this problem but has several other drawbacks such as low rate of reaction. In the present study, we have attempted to enhance glucose recovery from agricultural waste, namely, "sago hampas," through three cycles of enzymatic hydrolysis process. The substrate load at 7% (w/v) was seen to be suitable for the hydrolysis process with respect to the gelatinization reaction as well as sufficient mixture of the suspension for saccharification process. However, this study was focused on hydrolyzing starch of sago hampas, and thus to enhance concentration of glucose from 7% substrate load would be impossible. Thus, an alternative method termed as cycles I, II, and III which involved reusing the hydrolysate for subsequent enzymatic hydrolysis process was introduced. Greater improvement of glucose concentration (138.45 g/L) and better conversion yield (52.72%) were achieved with the completion of three cycles of hydrolysis. In comparison, cycle I and cycle II had glucose concentration of 27.79 g/L and 73.00 g/L, respectively. The glucose obtained was subsequently tested as substrate for bioethanol production using commercial baker's yeast. The fermentation process produced 40.30 g/L of ethanol after 16 h, which was equivalent to 93.29% of theoretical yield based on total glucose existing in fermentation media.
  7. Fulltext Surfactant modified/mediated thin-layer chromatographic systems for the analysis of amino acids
    Bhawani SA, Albishri HM, Khan ZA, Mohamad Ibrahim MN, Mohammad A
    J Anal Methods Chem, 2013;2013:973280.
    PMID: 24455427 DOI: 10.1155/2013/973280
    This review incorporates a large number of chromatographic systems modified by the surfactants. A large number of solvent systems and stationary phases are summarized in this paper. Three different kinds of surfactants (anionic, cationic, and nonionic) are used as modifiers for stationary phases as well as solvent systems. Surfactants are used at all the three different concentration levels (below, above, and at critical micelle concentration) where surfactants behave differently. Modifications of both stationary phases and solvent systems by surfactants produced a new generation of chromatographic systems. Microemulsion solvent systems are also incorporated in this paper. Microemulsion thin-layer chromatography is a new approach in the field of chromatography.
  8. Fulltext Antibiotics dispensing for URTIs by community pharmacists (CPs) and general medical practitioners in Penang, Malaysia: A comparative study using simulated patients (SPs)
    Alabid AH, Ibrahim MI, Hassali MA
    J Clin Diagn Res, 2014 Jan;8(1):119-23.
    PMID: 24596741 DOI: 10.7860/JCDR/2014/6199.3923
    BACKGROUND: In Malaysia, doctors in private clinics (often called dispensing doctors) are permitted to dispense medicines. This potentially may compromise rational dispensing of medicines in general and antibiotics in particular.
    AIM: This study explored, assessed and compared dispensing of antibiotics between Community Pharmacist (CP) and General Practitioners (GPs) regarding symptomatic diagnosis, antibiotic categories, adherence to therapeutic doses and promotion of generic antibiotics.
    METHOD: The study used trained Simulated Patients (SPs), who used a scenario of common cold symptoms at GP private clinics and community pharmacies to observe and explore the practice of antibiotics dispensing. The study was conducted within the period of May to September 2011 in Penang, Malaysia. The data was analysed using descriptive statistics, Chi-square and Fisher's Exact Tests at alpha level of 0.05.
    RESULTS: GPs dispensed more antibiotics than CPs (p= 0.001) for common cold symptoms. They dispensed more Amoxicillin (n = 14, 35%) than CPs (n = 11, 11%) (p < 0.001) and more Tetracycline (n = 3, 7.5%) while no CP dispensed this category (p = 0.022). On the other hand, CPs (n = 11, 11%) suggested brand antibiotics where as GPs dispensed only generic antibiotics (p < 0.001). Generally GPs comply better with the symptomatic diagnosis standard e.g. when asking SPs about the symptoms they had, all GPs (n = 40, 100%) complied better with this standard. Despite that, they dispensed more antibiotics (n = 26, 65%) than CPs (n = 29, 29%) (p = 0.001). GPs (n = 22, 55%) also are better than CPs (n = 16, 16%) in adherence to therapeutic doses (p< 0.001).
    CONCLUSION: Findings showed poor adherence to rational dispensing of antibiotics by both providers. Although, GPs adhere better to symptomatic diagnosis and therapeutic dosing of antibiotics than CPs, they unnecessarily prescribe and dispense more antibiotics for Upper respiratory tract infection (URTI) symptoms. Establishing prescription guidance and regulatory actions, especially for URTIs treatment, and separating of medication dispensing are seemed to be crucial steps for the reform.
    KEYWORDS: Community pharmacists; Dispensing doctors; Dispensing separation; General practitioners; Simulated patients ligament
  9. Biological activity and molecular docking studies of curcumin-related α,β-unsaturated carbonyl-based synthetic compounds as anticancer agents and mushroom tyrosinase inhibitors
    Bukhari SN, Jantan I, Unsal Tan O, Sher M, Naeem-Ul-Hassan M, Qin HL
    J Agric Food Chem, 2014 Jun 18;62(24):5538-47.
    PMID: 24901506 DOI: 10.1021/jf501145b
    Hyperpigmentation in human skin and enzymatic browning in fruits, which are caused by tyrosinase enzyme, are not desirable. Investigations in the discovery of tyrosinase enzyme inhibitors and search for improved cytotoxic agents continue to be an important line in drug discovery and development. In present work, a new series of 30 compounds bearing α,β-unsaturated carbonyl moiety was designed and synthesized following curcumin as model. All compounds were evaluated for their effects on human cancer cell lines and mushroom tyrosinase enzyme. Moreover, the structure-activity relationships of these compounds are also explained. Molecular modeling studies of these new compounds were carried out to explore interactions with tyrosinase enzyme. Synthetic curcumin-like compounds (2a-b) were identified as potent anticancer agents with 81-82% cytotoxicity. Five of these newly synthesized compounds (1a, 8a-b, 10a-b) emerged to be the potent inhibitors of mushroom tyrosinase, providing further insight into designing compounds useful in fields of food, health, and agriculture.
  10. Synthesis of α, β-unsaturated carbonyl based compounds as acetylcholinesterase and butyrylcholinesterase inhibitors: characterization, molecular modeling, QSAR studies and effect against amyloid β-induced cytotoxicity
    Bukhari SN, Jantan I, Masand VH, Mahajan DT, Sher M, Naeem-ul-Hassan M, et al.
    Eur J Med Chem, 2014 Aug 18;83:355-65.
    PMID: 24980117 DOI: 10.1016/j.ejmech.2014.06.034
    A series of novel carbonyl compounds was synthesized by a simple, eco-friendly and efficient method. These compounds were screened for anti-oxidant activity, in vitro cytotoxicity and for inhibitory activity for acetylcholinesterase and butyrylcholinesterase. The effect of these compounds against amyloid β-induced cytotoxicity was also investigated. Among them, compound 14 exhibited strong free radical scavenging activity (18.39 μM) while six compounds (1, 3, 4, 13, 14, and 19) were found to be the most protective against Aβ-induced neuronal cell death in PC12 cells. Compounds 4 and 14, containing N-methyl-4-piperidone linker, showed high acetylcholinesterase inhibitory activity as compared to reference drug donepezil. Molecular docking and QSAR (Quantitative Structure-Activity Relationship) studies were also carried out to determine the structural features that are responsible for the acetylcholinesterase and butyrylcholinesterase inhibitory activity.
  11. Knowledge, management and perceived barriers to treatment of molar-incisor hypomineralisation in general dental practitioners and dental nurses in Malaysia
    Hussein AS, Ghanim AM, Abu-Hassan MI, Manton DJ
    Eur Arch Paediatr Dent, 2014 Oct;15(5):301-7.
    PMID: 24569938 DOI: 10.1007/s40368-014-0115-2
    Molar-incisor hypomineralisation (MIH) is a global dental problem, yet little is known about the knowledge of the general dental practitioners (GDPs) and dental nurses (DNs) regarding this defect in South East Asia.
  12. Fulltext Nanoscale Diblock copolymer micelles: characterizations and estimation of the effective diffusion coefficients of biomolecules release through cylindrical diffusion model
    Amjad MW, Mohd Amin MC, Mahali SM, Katas H, Ismail I, Hassan MN, et al.
    PLoS One, 2014;9(8):e105234.
    PMID: 25133390 DOI: 10.1371/journal.pone.0105234
    Biomolecules have been widely investigated as potential therapeutics for various diseases. However their use is limited due to rapid degradation and poor cellular uptake in vitro and in vivo. To address this issue, we synthesized a new nano-carrier system comprising of cholic acid-polyethylenimine (CA-PEI) copolymer micelles, via carbodiimide-mediated coupling for the efficient delivery of small interfering ribonucleic acid (siRNA) and bovine serum albumin (BSA) as model protein. The mean particle size of siRNA- or BSA-loaded CA-PEI micelles ranged from 100-150 nm, with zeta potentials of +3-+11 mV, respectively. Atomic force, transmission electron and field emission scanning electron microscopy demonstrated that the micelles exhibited excellent spherical morphology. No significant morphology or size changes were observed in the CA-PEI micelles after siRNA and BSA loading. CA-PEI micelles exhibited sustained release profile, the effective diffusion coefficients were successfully estimated using a mathematically-derived cylindrical diffusion model and the release data of siRNA and BSA closely fitted into this model. High siRNA and BSA binding and loading efficiencies (95% and 70%, respectively) were observed for CA-PEI micelles. Stability studies demonstrated that siRNA and BSA integrity was maintained after loading and release. The CA-PEI micelles were non cytotoxic to V79 and DLD-1 cells, as shown by alamarBlue and LIVE/DEAD cell viability assays. RT-PCR study revealed that siRNA-loaded CA-PEI micelles suppressed the mRNA for ABCB1 gene. These results revealed the promising potential of CA-PEI micelles as a stable, safe, and versatile nano-carrier for siRNA and the model protein delivery.
  13. Sexual dysfunction among postmenopausal women
    Masliza W, Daud W, Yazid Bajuri M, Shuhaila A, Hatta S, Rohaizat Hassan M, et al.
    Clin Ter, 2014;165(2):83-9.
    PMID: 24770809 DOI: 10.7471/CT.2014.1681
    Female sexual dysfunction (FSD) has a major impact on interpersonal relationships and quality of life. For many women it has been emotionally distressing, physically disconcerting, and socially disruptive. To determine the prevalence and factors that contribute to female sexual dysfunction (FSD) and to evaluate the different sexual domains that influence sexual function amongst post menopausal women.
  14. Fulltext Modified smoothed particle hydrodynamics (MSPH) for the analysis of centrifugally assisted TiC-Fe-Al2O3 combustion synthesis
    Hassan MA, Mahmoodian R, Hamdi M
    Sci Rep, 2014;4:3724.
    PMID: 24430621 DOI: 10.1038/srep03724
    A modified smoothed particle hydrodynamic (MSPH) computational technique was utilized to simulate molten particle motion and infiltration speed on multi-scale analysis levels. The radial velocity and velocity gradient of molten alumina, iron infiltration in the TiC product and solidification rate, were predicted during centrifugal self-propagating high-temperature synthesis (SHS) simulation, which assisted the coating process by MSPH. The effects of particle size and temperature on infiltration and solidification of iron and alumina were mainly investigated. The obtained results were validated with experimental microstructure evidence. The simulation model successfully describes the magnitude of iron and alumina diffusion in a centrifugal thermite SHS and Ti + C hybrid reaction under centrifugal acceleration.
  15. Fulltext Immunochemical faecal occult blood test for colorectal cancer screening: a systematic review
    Syful Azlie MF, Hassan MR, Junainah S, Rugayah B
    Med J Malaysia, 2015 Feb;70(1):24-30.
    PMID: 26032525 MyJurnal
    A systematic review on the effectiveness and cost-effectiveness of Immunochemical faecal occult IFOBT for CRC screening was carried out. A total of 450 relevant titles were identified, 41 abstracts were screened and 18 articles were included in the results. There was fair level of retrievable evidence to suggest that the sensitivity and specificity of IFOBT varies with the cut-off point of haemoglobin, whereas the diagnostic accuracy performance was influenced by high temperature and haemoglobin stability. A screening programme using IFOBT can be effective for prevention of advanced CRC and reduced mortality. There was also evidence to suggest that IFOBT is cost-effective in comparison with no screening, whereby a two-day faecal collection method was found to be costeffective as a means of screening for CRC. Based on the review, quantitative IFOBT method can be used in Malaysia as a screening test for CRC. The use of fully automated IFOBT assay would be highly desirable.
  16. Effects of pre-treatment technologies on dark fermentative biohydrogen production: A review
    Bundhoo MA, Mohee R, Hassan MA
    J Environ Manage, 2015 Jul 1;157:20-48.
    PMID: 25881150 DOI: 10.1016/j.jenvman.2015.04.006
    Biohydrogen production from dark fermentation of lignocellulosic materials represents a huge potential in terms of renewable energy exploitation. However, the low hydrogen yield is currently hindering its development on industrial scale. This study reviewed various technologies that have been investigated for enhancing dark fermentative biohydrogen production. The pre-treatment technologies can be classified based on their applications as inoculum or substrates pre-treatment or they can be categorised into physical, chemical, physicochemical and biological based on the techniques used. From the different technologies reviewed, heat and acid pre-treatments are the most commonly studied technologies for both substrates and inoculum pre-treatment. Nevertheless, these two technologies need not necessarily be the most suitable since across different studies, a wide array of other emerging techniques as well as combined technologies have yielded positive findings. To date, there exists no perfect technology for either inoculum or substrate pre-treatment. Although the aim of inoculum pre-treatment is to suppress H2-consumers and enrich H2-producers, many sporulating H2-consumers survive the pre-treatment while some non-spore H2-producers are inhibited. Besides, several inoculum pre-treatment techniques are not effective in the long run and repeated pre-treatment may be required for continuous suppression of H2-consumers and sustained biohydrogen production. Furthermore, many technologies employed for substrates pre-treatment may yield inhibitory compounds that can eventually decrease biohydrogen production. Consequently, much research needs to be done to find out the best technology for both substrates and inoculum pre-treatment while also taking into consideration the energetic, economic and technical feasibility of implementing such a process on an industrial scale.
  17. Fulltext Common variation at 2p13.3, 3q29, 7p13 and 17q25.1 associated with susceptibility to pancreatic cancer
    Childs EJ, Mocci E, Campa D, Bracci PM, Gallinger S, Goggins M, et al.
    Nat Genet, 2015 Aug;47(8):911-6.
    PMID: 26098869 DOI: 10.1038/ng.3341
    Pancreatic cancer is the fourth leading cause of cancer death in the developed world. Both inherited high-penetrance mutations in BRCA2 (ref. 2), ATM, PALB2 (ref. 4), BRCA1 (ref. 5), STK11 (ref. 6), CDKN2A and mismatch-repair genes and low-penetrance loci are associated with increased risk. To identify new risk loci, we performed a genome-wide association study on 9,925 pancreatic cancer cases and 11,569 controls, including 4,164 newly genotyped cases and 3,792 controls in 9 studies from North America, Central Europe and Australia. We identified three newly associated regions: 17q25.1 (LINC00673, rs11655237, odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.19-1.34, P = 1.42 × 10(-14)), 7p13 (SUGCT, rs17688601, OR = 0.88, 95% CI = 0.84-0.92, P = 1.41 × 10(-8)) and 3q29 (TP63, rs9854771, OR = 0.89, 95% CI = 0.85-0.93, P = 2.35 × 10(-8)). We detected significant association at 2p13.3 (ETAA1, rs1486134, OR = 1.14, 95% CI = 1.09-1.19, P = 3.36 × 10(-9)), a region with previous suggestive evidence in Han Chinese. We replicated previously reported associations at 9q34.2 (ABO), 13q22.1 (KLF5), 5p15.33 (TERT and CLPTM1), 13q12.2 (PDX1), 1q32.1 (NR5A2), 7q32.3 (LINC-PINT), 16q23.1 (BCAR1) and 22q12.1 (ZNRF3). Our study identifies new loci associated with pancreatic cancer risk.
  18. Fulltext Erratum: (4Z)-4-Benzyl-idene-2-phenyl-1,3-oxazol-5(4H)-one. Corrigendum
    Asiri AM, Faidallah HM, Sobahi TR, Ng SW, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Nov 1;71(Pt 11):e4.
    PMID: 26617187 DOI: 10.1107/S2056989015019271
    In the paper by Asiri et al. [Acta Cryst. (2012), E68, o1154], the title and the chemical name of one of the reagents used in the synthesis are corrected.[This corrects the article DOI: 10.1107/S1600536812011579.].
  19. Fulltext Purification and Characterization of a Novel NAD(P)+-Farnesol Dehydrogenase from Polygonum minus Leaves
    Ahmad-Sohdi NA, Seman-Kamarulzaman AF, Mohamed-Hussein ZA, Hassan M
    PLoS One, 2015;10(11):e0143310.
    PMID: 26600471 DOI: 10.1371/journal.pone.0143310
    Juvenile hormones have attracted attention as safe and selective targets for the design and development of environmentally friendly and biorational insecticides. In the juvenile hormone III biosynthetic pathway, the enzyme farnesol dehydrogenase catalyzes the oxidation of farnesol to farnesal. In this study, farnesol dehydrogenase was extracted from Polygonum minus leaves and purified 204-fold to apparent homogeneity by ion-exchange chromatography using DEAE-Toyopearl, SP-Toyopearl, and Super-Q Toyopearl, followed by three successive purifications by gel filtration chromatography on a TSK-gel GS3000SW. The enzyme is a heterodimer comprised of subunits with molecular masses of 65 kDa and 70 kDa. The optimum temperature and pH were 35°C and pH 9.5, respectively. Activity was inhibited by sulfhydryl reagents, metal-chelating agents and heavy metal ions. The enzyme utilized both NAD+ and NADP+ as coenzymes with Km values of 0.74 mM and 40 mM, respectively. Trans, trans-farnesol was the preferred substrate for the P. minus farnesol dehydrogenase. Geometrical isomers of trans, trans-farnesol, cis, trans-farnesol and cis, cis-farnesol were also oxidized by the enzyme with lower activity. The Km values for trans, trans-farnesol, cis, trans-farnesol and cis, cis-farnesol appeared to be 0.17 mM, 0.33 mM and 0.42 mM, respectively. The amino acid sequences of 4 tryptic peptides of the enzyme were analyzed by MALDI-TOF/TOF-MS spectrometry, and showed no significant similarity to those of previously reported farnesol dehydrogenases. These results suggest that the purified enzyme is a novel NAD(P)+-dependent farnesol dehydrogenase. The purification and characterization established in the current study will serve as a basis to provide new information for recombinant production of the enzyme. Therefore, recombinant farnesol dehydrogenase may provide a useful molecular tool in manipulating juvenile hormone biosynthesis to generate transgenic plants for pest control.
  20. Fulltext Mechanical and Chemical Characterization of a TiC/C System Synthesized Using a Focus Plasma Arc
    Mahmoodian R, Hamdi M, Hassan MA, Akbari A
    PLoS One, 2015;10(6):e0130836.
    PMID: 26111217 DOI: 10.1371/journal.pone.0130836
    Titanium carbide-graphite (TiC/C) composite was successfully synthesized from Ti and C starting elemental powders using self-propagating high-temperature synthesis technique in an ultra-high plasma inert medium in a single stage. The TiC was exposed to a high-temperature inert medium to allow recrystallization. The product was then characterized using field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), Rietveld refinement, nanoindentation, and micro-hardness to determine the product's properties. The recorded micro-hardness of the product was 3660 HV, which is a 14% enhancement and makes is comparable to TiC materials.
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