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  1. Fulltext Effect of solid solution treatment on semisolid microstructure of Zn-22Al alloy
    Arif, M.A.M., Omar, M.Z., Muhamad, N.
    Pertanika Journal of Science & Technology, 2012;20(1):121-127.
    MyJurnal
    The effect of solid solution treatment on semisolid microstructure of Zn-22Al with developed dendrites was investigated. Zn-22Al is a zinc-based alloy with aluminium as its main alloying element. Producing Zn-22Al product by semisolid metal processing (SSM) offers significant advantages, such as reduction of macrosegregations, porosity and low forming efforts. Meanwhile, thermal and microstructure analyses of Zn-22Al alloy were studied using differential scanning calorimeter (DSC) and Olympus optical microscope. Solidus and liquidus of the alloy can be determined by DSC analysis. In addition, changes to the microstructures in response to solid solution treatments were also analyzed. The major effort of all the semi-solid technologies is the generation of small and spherical morphologies. Prior to the generation of spherical morphologies, the fine grains should be first produced. The as-cast samples were isothermally held at 315°C, ranging from 0.5 to 5 hours before they were partially re-melted at semisolid temperature of 438°C to produce solid globular grains structure in liquid matrix. The results indicated that a non-dendritic semisolid microstructure could not be obtained if the traditionally cast Zn-22Al alloy with developed dendrites was directly subjected to partial remelting. After solid solution treatment at 315°C, the black interdendritic eutectics were dissolved and gradually transformed into ß structure when the treatment time was increased. The microstructure of the solid solution treated sample changed into a small globular structure with the best shape factor of 0.9 and this corresponded to 40±16µm when the sample was treated for 3 hours, followed by directly partial remelting into its semi solid zone.
  2. Fulltext Emerging therapeutic potential of anti-psychotic drugs in the management of human glioma: A comprehensive review
    Kamarudin MNA, Parhar I
    Oncotarget, 2019 Jun 11;10(39):3952-3977.
    PMID: 31231472 DOI: 10.18632/oncotarget.26994
    Despite numerous advancements in the last decade, human gliomas such as astrocytoma and glioblastoma multiforme have the worst prognoses among all cancers. Anti-psychotic drugs are commonly prescribed to treat mental disorders among cancer patients, and growing empirical evidence has revealed their antitumor, anti-metastatic, anti-angiogenic, anti-proliferative, chemo-preventive, and neo-adjuvant efficacies in various in vitro, in vivo, and clinical glioma models. Anti-psychotic drugs have drawn the attention of physicians and researchers owing to their beneficial effects in the prevention and treatment of gliomas. This review highlights data on the therapeutic potential of various anti-psychotic drugs as anti-proliferative, chemopreventive, and anti-angiogenic agents in various glioma models via the modulation of upstream and downstream molecular targets involved in apoptosis, autophagy, oxidative stress, inflammation, and the cell cycle in in vitro and in vivo preclinical and clinical stages among glioma patients. The ability of anti-psychotic drugs to modulate various signaling pathways and multidrug resistance-conferring proteins that enhance the efficacy of chemotherapeutic drugs with low side-effects exemplifies their great potential as neo-adjuvants and potential chemotherapeutics in single or multimodal treatment approach. Moreover, anti-psychotic drugs confer the ability to induce glioma into oligodendrocyte-like cells and neuronal-like phenotype cells with reversal of epigenetic alterations through inhibition of histone deacetylase further rationalize their use in glioma treatment. The improved understanding of anti-psychotic drugs as potential chemotherapeutic drugs or as neo-adjuvants will provide better information for their use globally as affordable, well-tolerated, and effective anticancer agents for human glioma.
  3. Fulltext Transitioning pre-clinical glioblastoma models to clinical settings with biomarkers identified in 3D cell-based models: A systematic scoping review
    Phon BWS, Kamarudin MNA, Bhuvanendran S, Radhakrishnan AK
    Biomed Pharmacother, 2022 Jan;145:112396.
    PMID: 34775238 DOI: 10.1016/j.biopha.2021.112396
    Glioblastoma (GBM) remains incurable despite the overwhelming discovery of 2-dimensional (2D) cell-based potential therapeutics since the majority of them have met unsatisfactory results in animal and clinical settings. Incremental empirical evidence has laid the widespread need of transitioning 2D to 3-dimensional (3D) cultures that better mimic GBM's complex and heterogenic nature to allow better translation of pre-clinical results. This systematic scoping review analyses the transcriptomic data involving 3D models of GBM against 2D models from 22 studies identified from four databases (PubMed, ScienceDirect, Medline, and Embase). From a total of 499 genes reported in these studies, 313 (63%) genes were upregulated across 3D models cultured using different scaffolds. Our analysis showed that 4 of the replicable upregulated genes are associated with GBM stemness, epithelial to mesenchymal transition (EMT), hypoxia, and migration-related genes regardless of the type of scaffolds, displaying close resemblances to primitive undifferentiated tumour phenotypes that are associated with decreased overall survival and increased hazard ratio in GBM patients. The upregulation of drug response and drug efflux genes (e.g. cytochrome P450s and ABC transporters) mirrors the GBM genetic landscape that contributes to in vivo and clinical treatment resistance. These upregulated genes displayed strong protein-protein interactions when analysed using an online bioinformatics software (STRING). These findings reinforce the need for widespread transition to 3D GBM models as a relatively inexpensive humanised pre-clinical tool with suitable genetic biomarkers to bridge clinical gaps in potential therapeutic evaluations.
  4. Digital Display Preference of Electronic Gadgets for Visual Comfort: A Systematic Review
    Muhamad N, Amali NAN
    Iran J Public Health, 2023 Aug;52(8):1565-1577.
    PMID: 37744537 DOI: 10.18502/ijph.v52i8.13396
    BACKGROUND: Digital devices such as smartphones, tablets, computers, and laptops are used for various purposes. The digital display quality has been improved, making it less tiring and more favoured among users. This study aimed to review the visual comfort of digital devices and the preferences of digital display settings that enhance the visual comfort experienced by digital device users.

    METHODS: A search of PubMed, EBSCO host MEDLINE Complete, Scopus database, Google Scholar, and manual citation review was conducted, covering the period between 2010 and 2022. The criteria were selected based on the PRISMA statements. The search mainly focused on finding the existing literature on digital devices that contribute to visual discomfort and digital device settings that provide better visual comfort.

    RESULTS: The database search resulted in 533 references via the application of Microsoft Excel. There were 28 studies included in the final assessment. Twelve studies accounted for digital devices that contributed to visual discomfort, while another sixteen studies for digital device settings provided better visual comfort.

    CONCLUSION: Digital displays with high luminance contrast, positive polarity and adequate colour were preferred for better visual comfort. Meanwhile, smaller fonts were preferred for desktops and laptops, while larger fonts were favoured for smartphones. This study provides insights for digital display developers to learn and improve their display technology to fit the preferences expressed.

  5. Fulltext A laboratory study of fluoride concentration in infant formulas marketed in Malaysia and estimation of daily intake
    Mohd Desa, S. N. F., Muhamad, N. A., Mohd Nor, N. A., Abdul Razak, F., Abdul Manan, N. S., Abdul Manan, N. S., et al.
    International Food Research Journal, 2020;27(5):893-902.
    MyJurnal
    The window of maximum susceptibility for the development of dental fluorosis for anterior
    teeth is during the first two to three years of life. The primary source of fluoride intake for
    infants at this age is mainly from the diet including infant formula. Thus, the present work
    aimed to investigate the fluoride concentration in commercially available Malaysian infant
    formulas that required reconstitution before consumption. A total of 29 infant formulas available in the Malaysian market were reconstituted with deionised water, fluoridated tap water,
    and filtered tap water. The fluoride concentration of the infant formulas was analysed directly
    using a fluoride ion selective electrode. The daily fluoride intake estimation from the infant
    formulas was calculated using the median infant body weight and recommended volumes for
    formula consumption from newborn to > 12 months of age. Results showed that the fluoride
    concentration of the infant formulas when reconstituted with deionised water ranged between
    0.009 to 0.197 mg/L that contributed to the estimated daily fluoride intake ranging from 0.005
    to 0.100 mg (total intake per day) or 0.001 to 0.025 mg/kg (total intake per body weight/day).
    The fluoride concentration in the selected infant formulas was low, but after reconstitution
    with fluoridated tap water, the overall fluoride concentration in infant formulas sample significantly increased (p < 0.001). Nevertheless, the estimated daily fluoride intake from infant
    formulas alone did not exceed the lowest-observed-adverse-effect level (LOAEL) of fluoride
    at 0.10 mg/kg/day.
  6. Momordica charantia ointment accelerates diabetic wound healing and enhances transforming growth factor-β expression
    Hussan F, Teoh SL, Muhamad N, Mazlan M, Latiff AA
    J Wound Care, 2014 Aug;23(8):400, 402, 404-7.
    PMID: 25139598 DOI: 10.12968/jowc.2014.23.8.400
    Transforming growth factor-β (TGF-β) plays an important role in wound healing. Delayed wound healing is a consequence of diabetes, leading to high morbidity and poor quality of life. Momordica charantia (MC) fruit possesses anti-diabetic and wound healing properties. This study aimed to explore the changes in TGF-β expression in diabetic wounds treated with topical MC fruit extract.
  7. Urea Output by L3 Teladorsagia circumcincta and some Properties of Two Urea Producing Enzymes
    Muhamad N, Walker L, Simcock D, Pedley K, Simpson H, Brown S
    Iran J Parasitol, 2013 Jan;8(1):137-44.
    PMID: 23682271
    Like several other parasites, Teladorsagia circumcincta secretes or excretes urea, but neither the rate of efflux nor the possible metabolic sources of the urea has been considered.
  8. Fulltext Internal jugular vein height and inferior vena cava diameter measurement using ultrasound to determine central venous pressure: a correlation study
    Nik Muhamad NA, Safferi RS, Robertson CE
    Med J Malaysia, 2015 Apr;70(2):63-6.
    PMID: 26162379 MyJurnal
    OBJECTIVE: To determine the correlation between central venous pressure (CVP) measured by conventional central venous access and ultrasonographic measurement of internal jugular vein (IJV) height and inferior vena cava (IVC) diameter.
    METHODS: A prospective, cross-sectional, convenience sampling observational study.
    RESULTS: 25 patients from the Emergency Department (ED) Universiti Kebangsaan Malaysia Medical Centre (UKMMC) were studied between 1st March and 30th April 2013. The median age was 63 years (95% CI 54-67). There was a significant correlation between IJV height and CVP using central venous access (r=0.64 p<0.001). Correlation between IVC diameter in end expiration and CVP was 0.74 (p<0.001). An IJV height measurement >8cm predicted a CVP >8cm H2O (sensitivity 71.4%, specificity of 83.3%).
    CONCLUSION: Measurement of IJV height and IVC diameter by ultrasonography correlates well with invasive CVP and is useful for the assessment of volume status in critically ill patients in the ED.
    Study site: Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur
  9. The Kinetics of Enzyme Mixtures
    Brown S, Muhamad N, C Pedley K, C Simcock D
    Mol Biol Res Commun, 2014 Mar;3(1):21-32.
    PMID: 27843974
    Even purified enzyme preparations are often heterogeneous. For example, preparations of aspartate aminotransferase or cytochrome oxidase can consist of several different forms of the enzyme. For this reason we consider how different the kinetics of the reactions catalysed by a mixture of forms of an enzyme must be to provide some indication of the characteristics of the species present. Based on the standard Michaelis-Menten model, we show that if the Michaelis constants (Km) of two isoforms differ by a factor of at least 20 the steady-state kinetics can be used to characterise the mixture. However, even if heterogeneity is reflected in the kinetic data, the proportions of the different forms of the enzyme cannot be estimated from the kinetic data alone. Consequently, the heterogeneity of enzyme preparations is rarely reflected in measurements of their steady-state kinetics unless the species present have significantly different kinetic properties. This has two implications: (1) it is difficult, but not impossible, to detect molecular heterogeneity using kinetic data and (2) even when it is possible, a considerable quantity of high quality data is required.
  10. Compliance of Malaysian healthcare workers towards tuberculosis prevention programmes in workplace: An exploratory sequential mixed method study protocol
    Halim I, Reffin N, Sharifa Ezat WP, Muhamad NA, Harith AA
    Med J Malaysia, 2021 Nov;76(6):857-864.
    PMID: 34806673
    INTRODUCTION: The World Health Organization (WHO) stated that the incidence of tuberculosis among healthcare workers is increasing yearly and exceeds the incidence of tuberculosis in the community in almost all the countries that report to the WHO. The problem is greater in countries with high burden of tuberculosis disease in the community. The cause of this problem may be contributed by the attitudes of the healthcare workers themselves, such as non-compliance of the procedures at their work tasks meant to prevent them from contracting the disease. Therefore, this study aims to assess the perceptions and the behaviours of healthcare workers in relation to compliance towards prevention activities on tuberculosis at their workplace.

    MATERIALS AND METHODS: We plan to conduct a two-phase exploratory sequential mixed method study to determine the factors affecting compliance of Malaysian healthcare workers towards tuberculosis prevention programmes in their workplace based on the guidelines of the Ministry of Health, Malaysia. Phase one is a qualitative study with a focus group discussion and questionnaire development and phase two is a quantitative study where data will be collected among healthcare workers in government clinics and hospitals in Selangor. The data from phase one will be analysed using Atlas.Ti software for thematic analysis and data from phase two will be analysed using SEM AMOS software for structural equation modelling.

  11. Illicit drug use among school-going adolescents in Malaysia
    Yusoff F, Sahril N, Rasidi NM, Zaki NA, Muhamad N, Ahmad N
    Asia Pac J Public Health, 2014 Sep;26(5 Suppl):100S-7S.
    PMID: 25038195 DOI: 10.1177/1010539514542425
    Illicit drug use among adolescents has become a public health issue in Malaysia. This study was from the Global School-Based Student Health Survey (GSHS) and aimed to determine the prevalence of and factors associated with illicit drug use among school-going adolescents in Malaysia. A 2-stage stratified cluster sampling method was used and data were collected via a self-administered questionnaire. A total of 25 507 students participated in the study. The prevalence of adolescents who ever used illicit drugs was 1.7%. Adolescents who ever used illicit drugs were associated with current smoking (adjusted odds ratio [aOR] = 6.99; 95% CI = 5.19, 9.40), current alcohol use (aOR = 4.63; 95% CI = 3.43, 6.26), ever having sex (aOR = 4.76; 95% CI = 3.54, 6.41), truancy (aOR = 1.43; 95% CI = 1.07, 1.90), lack of peer support (aOR = 1.47; 95% CI = 1.07, 2.03), and lack of parental monitoring (aOR = 1.71; 95% CI = 1.22, 2.39). Public health intervention should be addressed to prevent illicit drug used among adolescents.
    Study name: Global School-Based Student Health Survey (GSHS)
  12. The initial kinetics of NH3/NH4(+) efflux from L3 Teladorsagia circumcincta
    Muhamad N, Walker LR, Pedley KC, Simcock DC, Brown S
    Parasitol Int, 2012 Sep;61(3):487-92.
    PMID: 22562002 DOI: 10.1016/j.parint.2012.04.003
    The initial rate of NH(3)/NH(4)(+) accumulation in a medium containing L(3) Teladorsagia circumcincta was 0.18-0.6 pmol h(-1) larva(-1), which increased linearly with larval density. However it appeared that the larva-generated external concentration of NH(3)/NH(4)(+) did not exceed about 130 μM. The rate of NH(3)/NH(4)(+) accumulation increased with temperature between 4 °C and 37 °C, declined with increasing pH or increasing external NH(3)/NH(4)(+) concentration and was not significantly affected by the concentration of the phosphate buffer or by exsheathing the larvae. We infer from these data that the efflux of NH(3)/NH(4)(+) is a diffusive process and that the secreted or excreted NH(3)/NH(4)(+) is generated enzymatically rather than dissociating from the surface of the nematode. The enzymatic source of the NH(3)/NH(4)(+) is yet to be identified. Since the concentration of NH(3)/NH(4)(+) in the rumen and abomasum is higher than 130 μM, it is unlikely that T. circumcincta contributes to it, but NH(3)/NH(4)(+) may be accumulated from the rumen fluid by the nematode.
  13. Fulltext Influence of Multiwalled Carbon Nanotubes on the Rheological Behavior and Physical Properties of Kenaf Fiber-Reinforced Polypropylene Composites
    Abdul Azam F', Razak Z, Md Radzi MKF, Muhamad N, Che Haron CH, Sulong AB
    Polymers (Basel), 2020 Sep 13;12(9).
    PMID: 32933225 DOI: 10.3390/polym12092083
    The incorporation of kenaf fiber fillers into a polymer matrix has been pronounced in the past few decades. In this study, the effect of multiwalled carbon nanotubes (MWCNTs) with a short kenaf fiber (20 mesh) with polypropylene (PP) added was investigated. The melt blending process was performed using an internal mixer to produce polymer composites with different filler contents, while the suitability of this melt composite for the injection molding process was evaluated. Thermogravimetric analysis (TGA) was carried out to investigate the thermal stability of the raw materials. Rheological analyses were conducted by varying the temperature, load factor, and filler content. The results demonstrate a non-Newtonian pseudoplastic behavior in all samples with changed kenaf fillers (10 to 40 wt %) and MWCNT contents (1 to 4 wt %), which confirm the suitability of the feedstock for the injection molding process. The addition of MWCNTs had an immense effect on the viscosity and an enormous reduction in the feedstock flow behavior. The main contribution of this work is the comprehensive observation of the rheological characteristics of newly produced short PP/kenaf composites that were altered after MWCNT additions. This study also presented an adverse effect on the composites containing MWCNTs, indicating a hydrophilic property with improved water absorption stability and the low flammability effect of PP/kenaf/MWCNT composites. This PP/kenaf/MWCNT green composite produced through the injection molding technique has great potential to be used as car components in the automotive industry.
  14. Incorporation of wollastonite bioactive ceramic with titanium for medical applications: An overview
    Zakaria MY, Sulong AB, Muhamad N, Raza MR, Ramli MI
    Mater Sci Eng C Mater Biol Appl, 2019 Apr;97:884-895.
    PMID: 30678979 DOI: 10.1016/j.msec.2018.12.056
    Titanium-ceramic composites are potential implant material candidates because of their unique mechanical properties and biocompatibility. This review focused on the latest advancement in processing of titanium-ceramic materials. Previously, titanium-ceramic incorporated using different coating techniques, i.e., plasma spraying and electrophoretic depositions, to enhance the biocompatibility of the implants. A major drawback in these coating methods is the growth of tissue at only the surface of the composite and might peel off over time. Recently, metal-ceramic composite was introduced via powder metallurgy method such as powder injection moulding. A porous structure can be obtained via powder metallurgy. Producing a porous titanium-ceramic structure would improve the mechanical properties, biocompatibility and tissue growth within the structure. Hence, further research needed to be done by considering the potential of powder injection moulding method which offer lower costs and more complex shapes for future implant.
  15. The kinetic properties of the glutamate dehydrogenase of Teladorsagia circumcincta and their significance for the lifestyle of the parasite
    Muhamad N, Simcock DC, Pedley KC, Simpson HV, Brown S
    Comp Biochem Physiol B Biochem Mol Biol, 2011 Jun;159(2):71-7.
    PMID: 21296180 DOI: 10.1016/j.cbpb.2011.01.008
    Like other nematodes, both L(3) and adult Teladosagia circumcincta secrete or excrete NH(3)/NH(4)(+), but the reactions involved in the production are unclear. Glutamate dehydrogenase is a significant source NH(3)/NH(4)(+) in some species, but previous reports indicate that the enzyme is absent from L(3)Haemonchus contortus. We show that glutamate dehydrogenase was active in both L(3) and adult T. circumcincta. The apparent K(m)s of the L(3) enzyme differed from those of the adult enzyme, the most significant of these being the increase in the K(m) for NH(4)(+) from 18mM in L(3) to 49mM in adults. The apparent V(max) of the oxidative deamination reaction was greater than that of the reductive reaction in L(3), but this was reversed in adults. The activity of the oxidative reaction of the L(3) enzyme was not affected by adenine nucleotides, but that of the reductive reaction was stimulated significantly by either ADP or ATP. The L(3) enzyme was more active with NAD(+) than it was with NADP(+), although the activities supported by NADH and NADPH were similar at saturating concentrations. While the activity of the oxidative reaction was sufficient to account for the NH(3)/NH(4)(+) efflux we have previously reported, the reductive amination reaction was likely to be more active.
  16. Fulltext The Effect of Alkali Treatment on Physical, Mechanical and Thermal Properties of Kenaf Fiber and Polymer Epoxy Composites
    Ismail NF, Mohd Radzuan NA, Sulong AB, Muhamad N, Che Haron CH
    Polymers (Basel), 2021 Jun 19;13(12).
    PMID: 34205236 DOI: 10.3390/polym13122005
    The use of kenaf fiber as a reinforcement material for polymer composites is gaining popularity, especially in the production of automotive components. The main objective of this current work is to relate the effect of alkali treatment on the single fiber itself and the composite material simultaneously. The effect of temperature condition during mechanical testing is also investigated. Composite materials with discontinuous natural kenaf fibers and epoxy resin were fabricated using a compression moulding process. The epoxy composites were reinforced with 50 wt% untreated and treated kenaf fibers. The kenaf fiber was treated with NaOH solution (6% by weight) for 24 h at room temperature. Kenaf fiber treated with NaOH treatment had a clean surface and no impurities. For the first time we can see that alkali treatment had a damaging effect on the mechanical properties of kenaf fibers itself and the treated kenaf/epoxy composites. The composite reinforced with untreated kenaf fiber and treated kenaf fiber showed increased tensile strength (72.85% and 12.97%, respectively) compared to the neat epoxy. Reinforcement of the composite with treated kenaf fiber decreased the tensile strength due to the fiber pull out and the formation of voids which weakens the adhesion between the fibers and matrix. The temperature conditions also play an important role in composites with a significant impact on the deterioration of composite materials. Treated kenaf fiber has thermal stability and is not sensitive to temperature and as a result reinforcement with treated kenaf gives a lower loss value of 76%.
  17. Metastatic Pleomorphic Adenoma in the infratemporal fossa and neck following total parotidectomy after 30 years
    Wong DKC, Muhamad NS, Sobri SS, Amin WAM, Yusof Z
    Med J Malaysia, 2019 04;74(2):85-86.
    PMID: 31079134
    Metastasising pleomorphic adenoma is rare and may occur years after surgical excision of a pleomorphic adenoma (PA). We present a 61-year-old woman with a right infratemporal PA with metastases to the cervical lymph nodes after 30 years following a total parotidectomy. She was treated successfully with a resection of the tumour with combined neck and mandibulotomy approach along with postoperative radiotherapy given subsequently.
  18. Fulltext Micro-Injection Molding and Debinding Behavior of Hydroxyapatite/Zirconia Bi-Materials Fabricated by Two-Component Micro-Powder Injection Molding Process
    Basir A, Muhamad N, Sulong AB, Amin MBM, Jamadon NH, Radzuan NAM
    Materials (Basel), 2023 Sep 24;16(19).
    PMID: 37834512 DOI: 10.3390/ma16196375
    The micro-scale joining of two different materials using two-component micro-powder injection molding (2C-µPIM) is an intriguing technique. The formation of defects in bi-materials at different processing stages makes this technique challenging. This study presents the fabrication of defect-free bi-material micro-parts containing hydroxyapatite (HA) and 3 mol% yttria-stabilized zirconia (3YSZ) via 2C-µPIM. Critical powder volume concentrations (CPVCs) of 61.7 vol% and 47.1 vol% were obtained for the HA and 3YSZ powders, respectively. Based on the CPVCs, the optimal loadings for the HA and 3YSZ powders were selected as 60 vol% and 45 vol%, respectively. The HA and 3YSZ feedstocks were prepared by separately mixing the optimal powder contents with low-density polyethylene (LDPE) and palm stearin binders. The feedstocks displayed pseudoplastic behavior, and the lowest ranges of viscosity for the HA and 3YSZ at a temperature of 180 °C were 157.1-1392.5 Pa·s and 726.2-985.5 Pa·s, respectively. The feedstocks were injected to produce green HA/3YSZ micro-sized components. It was found that a solvent debinding temperature of 70 °C removed 60.6% of the palm stearin binder from the sample. In the thermal debinding stage, the open channels that formed in the bi-material sample's solvent debound at 70 °C and contributed to the removal of 93 to 95% of the binder system. When the debound bi-materials were sintered at 1300 °C, the highest relative density of 96.3% was obtained. The sintering operation revealed a linear shrinkage between 13 and 17% in the sintered HA/3YSZ micro-parts.
  19. Protective effects of Tualang honey on bone structure in experimental postmenopausal rats
    Zaid SS, Sulaiman SA, Othman NH, Soelaiman IN, Shuid AN, Mohamad N, et al.
    Clinics (Sao Paulo), 2012 Jul;67(7):779-84.
    PMID: 22892923
    OBJECTIVE: The objective of this study was to evaluate the effects of Tualang honey on trabecular structure and compare these effects with those of calcium supplementation in ovariectomized rats.

    METHODS: Forty female, Sprague-Dawley rats were randomly divided into five groups (n =8): four controls and one test arm. The control arm comprised a baseline control, sham-operated control, ovariectomized control, and ovariectomized calcium-treated rats (receiving 1% calcium in drinking water ad libitum). The test arm was composed of ovariectomized, Tualang honey-treated rats (received 0.2 g/kg body weight of Tualang honey). Both the sham-operated control and ovariectomized control groups received vehicle treatment (deionized water), and the baseline control group was sacrificed without treatment.

    RESULTS: All rats were orally gavaged daily for six weeks after day one post-surgery. The bone structural analysis of rats in the test arm group showed a significant increase in the bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) and a significant decrease in inter-trabecular space (Tb.Sp) compared with the ovariectomized control group. The trabecular thickness (Tb.Th) in the test arm group was significantly higher compared with the ovariectomized-calcium treated group, and the inter-trabecular space (Tb.Sp) in the test arm group was significantly narrower compared with the ovariectomized-calcium treated group.

    CONCLUSION: In conclusion, ovariectomized rats that received Tualang honey showed more improvements in trabecular bone structure than the rats that received calcium.

  20. Fulltext Effect of sintering parameters on physical and mechanical properties of powder injection moulded stainless steel-hydroxyapatite composite
    Ramli MI, Sulong AB, Muhamad N, Muchtar A, Arifin A, Mohd Foudzi F, et al.
    PLoS One, 2018;13(10):e0206247.
    PMID: 30359433 DOI: 10.1371/journal.pone.0206247
    The combination of metallic bio-inert material, stainless-steel 316L (SS316L) and a bio-active material, hydroxyapatite (HA) can produce a composite which has superior properties for orthopaedic applications. The main objective of this study is to investigate the effects of sintering temperature and holding time on the physical and mechanical properties of the sintered part. 50wt.% SS316L and 50wt.% HA were mixed with a binder system of palm stearin (PS) and polyethylene (PE) at 61 vol.% powder loading. Rheological properties show a pseudo-plastic behaviour of the feedstock, where viscosity decreases with increasing shear rate. The feedstock was injection moulded into a tensile bar shape while thermal debinding was carried out at 320°C and 500°C. The brown parts were sintered at 1000, 1100, 1200 and 1300°C, with three different sintering times of 1, 3 and 5 hours in the furnace. It was found that the highest sintered density measured was 95.61% of the theoretical density. In addition, the highest hardness and Young's modulus measured were 150.45 HV and 52.61 GPa respectively, which are higher than those of human bone. The lowest percentage of carbon content was 0.022wt.% given by the sample sintered at 1300°C for 1 hour. Therefore, SS316L/HA composite with good mechanical and physical properties was successfully produced through the PIM process.
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