Displaying publications 41 - 60 of 161 in total

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  1. Ling JL, Teo SH, Mohamed Al-Fayyadh MZ, Mohamed Ali MR, Ng WM
    Arthroscopy, 2019 02;35(2):596-604.
    PMID: 30611592 DOI: 10.1016/j.arthro.2018.08.038
    PURPOSE: To assess the effectiveness of a low-cost self-made arthroscopic camera (LAC) in basic arthroscopic skills training compared with a commercial arthroscopic camera (CAC).

    METHODS: One hundred fifty-three orthopaedic residents were recruited and randomly assigned to either the LAC or CAC. They were allocated 2 practice sessions, with 20 minutes each, to practice 4 given arthroscopic tasks: task 1, transferring objects; task 2, stacking objects; task 3, probing numbers; and task 4, stretching rubber bands. The time taken for participants to complete the given tasks was recorded in 3 separate tests; before practice, immediately after practice, and after a period of 3 months. A comparison of the time taken between both groups to complete the given tasks in each test was measured as the primary outcome.

    RESULTS: Significant improvements in time completion were seen in the post-practice test for both groups in all given arthroscopic tasks, each with P < .001. However, there was no significant difference between the groups for task 1 (P = .743), task 2 (P = .940), task 3 (P = .932), task 4 (P = .929), and total (P = .944). The outcomes of the tests (before practice, after practice, and at 3 months) according to repeated measures analysis of variance did not differ significantly between the groups in task 1 (P = .475), task 2 (P = .558), task 3 (P = .850), task 4 (P = .965), and total (P = .865).

    CONCLUSIONS: The LAC is equally as effective as the CAC in basic arthroscopic skills training with the advantage of being cost-effective.

    CLINICAL RELEVANCE: In view of the scarcity in commercial arthroscopic devices for trainees, this low-cost device, which trainees can personally own and use, may provide a less expensive and easily available way for trainees to improve their arthroscopic skills. This might also cultivate more interest in arthroscopic surgery among junior surgeons.

    Matched MeSH terms: Rubber
  2. Sofian Ibrahim, Keong, Chai Chee, Ratnam, Chantara Thevy, Khairiah Badri
    ASM Science Journal, 2018;11(2):67-75.
    MyJurnal
    Radiation pre-vulcanised natural rubber latex (RVNRL) prepared by using gamma irradiation technique has many advantages over the conventionally prepared sulphur pre-vulcanised natural rubber latex (SPVL). Despite the fact that many potential latex dipped products can be made from RVNRL, little effort was made to fully commercialise the products because of the inferior strength of RVNRL products compared to SPVL products. An attempt was made to improve the tensile strength of RVNRL by combining both radiation and peroxide vulcanisation in order to ensure that the products will not tear or fail, and has sufficient stretch. Hexanediol diacrylate (HDDA) plays the main role as sensitizer during radiation vulcanisation and tert-butyl hydroperoxide (t-BHPO) as the co-sensitizer in peroxide vulcanisation. Pre-vulcanised natural rubber latex dipped films via hybrid radiation and peroxidation vulcanisations obtained showed tensile strength of 26.7 MPa, an increment of more than 15% compared to controlled film (22.5 MPa). Besides, the crosslink percentage of the rubber films also showed around 5% increment from 90.7% to 95.6%.
    Matched MeSH terms: Rubber
  3. Ahmad Fikri Abdul Karim, Hanafi Ismail, Zulkifli Mohamad Ariff
    Sains Malaysiana, 2018;47:2163-2169.
    This research was carried out to study the effects of kenaf loading and alkaline treatment on tensile properties, density,
    thermal and morphological properties of kenaf filled natural rubber latex foam (NRLF). Samples were prepared using a
    Dunlop method. From the results, increasing loading of kenaf reduced the tensile strength and elongation at break for
    both samples, treated and untreated kenaf filled NRLF. Meanwhile, modulus at 100% elongation and density increased
    with an increased in kenaf loading. Samples with treated kenaf showed higher tensile strength, modulus at 100%
    elongation and density but low in elongation at break as compared with samples with untreated kenaf. Thermal study
    by using thermogravimetric analysis (TGA) showed that thermal stability reduced with increased in kenaf loading for
    both samples. Samples with treated kenaf have higher thermal stability compared with samples of untreated kenaf. The
    filler-matrix interaction and the pores size variation of both samples was clearly seen in the micrograph images by using
    scanning electron microscope (SEM).
    Matched MeSH terms: Rubber
  4. Taweepreda W
    Sains Malaysiana, 2014;43:241-245.
    Biodegradable polymeric films, obtained from chitosan/natural rubber latex (CS/NRL) blends with different compositions, have been prepared by wetting process. The blends were characterized by dynamic mechanical thermal analysis (DMTA) and found that the CS/NRL blends are thermodynamically incompatible. This is evident from the presence of two glass transitions, corresponding to CS and NRL phases in the blend. The mechanical properties of the CS/NRL blends were improved with increasing the amount of chitosan and after surface treatment with sulphuric acid due to the sulfonate ionic interaction. The dielectric properties was determined using Precision LCR meter in the frequency range 75 kHz up to 30 MHz. After CS/NRL surface treatment with sulphuric acid at high content of chitosan showed the highest dielectric constant. The surface properties of the CS/NRL blend films before and after surface treatment were confirmed by atomic force microscopy (AFM), respectively.
    Matched MeSH terms: Rubber
  5. Chen RS, Mohd Ruf MFH, Shahdan D, Ahmad S
    PLoS One, 2019;14(9):e0222662.
    PMID: 31545820 DOI: 10.1371/journal.pone.0222662
    Thermoplastic natural rubber (TPNR) was compounded with graphene nanoplatelets (GNP) via ultrasonication and melt blending. The effects of ultrasonication period (1-4 hours) and GNP weight fraction (0.5, 1.0, 1.5 and 2.0 wt.%) on the mechanical, thermal and conductivity properties were investigated. Results showed that the 3 hours of ultrasonic treatment on LNR/GNP gave the greatest improvement in tensile strength of 25.8% (TPNR/GNP nanocomposites) as compared to those without ultrasonication. The TPNR nanocomposites containing 1.5 wt.% GNP exhibited the highest strength (16 MPa for tensile, 14 MPa for flexural and 11 kJm-2 for impact) and modulus (556 MPa and 869 MPa for tensile and flexural, respectively). The incorporation of GNP had enhanced the thermal stability. It can be concluded that the GNP had imparted the thermally and electrically conductive nature to the TPNR blend.
    Matched MeSH terms: Rubber
  6. Nuriah Mohamad, Azlin Suhaida Azmi, Fathilah Ali, Mohamad Firdaus Omar
    MyJurnal
    Sulfur has been highly sought by many industries everywhere around the world for various applications. This exceptionally useful element has been largely manufactured especially in powder form each year reflecting its increase in demand in line with technological advancement and uses for various product applications. The manufacturing processes include mining as well as chemical reactions in Claus Process. Rubber industries normally use abundance of sulfur in their latex compound to introduce vulcanization. The geneal concern of sulfur for rubber vulcanization is dispersibility in the rubber matrix due to improper optimization of its preparation process prior to latex compounding. Another crucial issue is crystallization of soluble sulfur from its insoluble origin, either during or post-rubber vulcanization that constitutes to formation of sulfur bloom that grows on the surface of the rubber articles. It is known that both issues are related to the process conditions and compounding recipe that could not be fully solved. Various studies have been conducted to minimize such occurences – from process optimization to sulfur chemistry itself – and of continuous improvement and innovation to solve various threats in sulfur applications. This paper reviews on detailed description on elemental sulfur, of respective industrial applications, and most importantly highlights on sulfur trends and issues normally encountered.
    Matched MeSH terms: Rubber
  7. Hau Hong DL, Mohammed BS, Al-Fakih A, Wahab MMA, Liew MS, Amran YHM
    Materials (Basel), 2020 Jun 24;13(12).
    PMID: 32599798 DOI: 10.3390/ma13122831
    Engineered cementitious composite (ECC) was discovered as a new substitute of conventional concrete as it provides better results in terms of tensile strain, reaching beyond 3%. From then, more studies were done to partially replace crumb rubber with sand to achieve a more sustainable and eco-friendlier composite from the original ECC. However, the elastic modulus of ECC was noticeably degraded. This could bring potential unseen dangerous consequences as the fatigue might happen at any time without any sign. The replacement of crumb rubber was then found to not only bring a more sustainable and eco-friendlier result but also increase the ductility and the durability of the composite, with lighter specific gravity compared to conventional concrete. This study investigated the effects of crumb rubber (CR) and graphene oxide (GO) toward the deformable properties of rubberized ECC, including the compressive strength, elastic modulus, Poisson's ratio, and drying shrinkage. Central composite design (CCD) was utilized to provide 13 reasonable trial mixtures with the ranging level of CR replacement from 0-30% and that of GO from 0.01-0.08%. The results show that GO increased the strength of the developed GO-RECC. It was also found that the addition of CR and GO to ECC brought a notable improvement in mechanical and deformable properties. The predicted model that was developed using response surface methodology (RSM) shows that the variables (compression strength, elastic modulus, Poisson's ratio, and drying shrinkage) rely on the independent (CR and GO) variables and are highly correlated.
    Matched MeSH terms: Rubber
  8. Sabapathy L, Mohammed BS, Al-Fakih A, Wahab MMA, Liew MS, Amran YHM
    Materials (Basel), 2020 Jul 13;13(14).
    PMID: 32668788 DOI: 10.3390/ma13143125
    The objective of this research was to determine the durability of an engineered cementitious composite (ECC) incorporating crumb rubber (CR) and graphene oxide (GO) with respect to resistance to acid and sulphate attacks. To obtain the mix designs used for this study, response surface methodology (RSM) was utilized, which yielded the composition of 13 mixes containing two variables (crumb rubber and graphene oxide). The crumb rubber had a percentage range of 0-10%, whereas the graphene oxide was tested in the range of 0.01-0.05% by volume. Three types of laboratory tests were used in this study, namely a compressive test, an acid attack test to study its durability against an acidic environment, and a sulphate attack test to examine the length change while exposed to a sulphate solution. Response surface methodology helped develop predictive responsive models and multiple objectives that aided in the optimization of results obtained from the experiments. Furthermore, a rubberized engineered cementitious composite incorporating graphene oxide yielded better chemical attack results compared to those of a normal rubberized engineered cementitious composite. In conclusion, nano-graphene in the form of graphene oxide has the ability to enhance the properties and overcome the limitations of crumb rubber incorporated into an engineered cementitious composite. The optimal mix was attained with 10% crumb rubber and 0.01 graphene oxide that achieved 43.6 MPa compressive strength, 29.4% weight loss, and 2.19% expansion. The addition of GO enhances the performance of rubberized ECC, contributing to less weight loss due to the deterioration of acidic media on the ECC. It also contributes to better resistance to changes in the length of the rubberized ECC samples.
    Matched MeSH terms: Rubber
  9. Hasma H, Subramaniam A
    Lipids, 1978 Dec;13(12):905-7.
    PMID: 27520427 DOI: 10.1007/BF02533847
    Methyl esters from the triglyceride fraction of the neutral lipids of natural rubber latex were found by gas liquid chromatography to contain about 90% of a furanoid acid. Spectroscopic analysis identified the acid as 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid.
    Matched MeSH terms: Rubber
  10. Santy JE, Kamal J, Abdul-Rashid AH, Ibrahim S
    Malays Orthop J, 2015 Jul;9(2):13-16.
    PMID: 28435603 MyJurnal DOI: 10.5704/MOJ.1507.006
    Percutaneous pinning after closed reduction is commonly used to treat supracondylar fractures of the humerus in children. Minor pin tract infections frequently occur. The aim of this study was to prevent pin tract infections using a rubber stopper to reduce irritation of the skin against the Kirschner (K) wire following percutaneous pinning. Between July 2011 and June 2012, seventeen children with closed supracondylar fracture of the humerus of Gartland types 2 and 3 were treated with this technique. All patients were treated with closed reduction and percutaneous pinning and followed up prospectively. Only one patient, who was a hyperactive child, developed pin tract infection due to softening of the plaster slab. We found using the rubber stopper to be a simple and inexpensive method to reduce pin tract infections following percutaneous pinning.
    Matched MeSH terms: Rubber
  11. Tan, S.G.
    MyJurnal
    Malaysia, with her tropical jungles, mangroves and seas, is blessed with riches in biodiversity, being one of the twelve megabiodiversity countries on earth. Genetics has contributed substantially to the success of our country's agricultural production especially of rubber and palm oil. Hence, it should play a pivotal role in helping Malaysia fulfill her responsibility to identify, characterize and sustainably utilize her numerous indigenous bioresources for the benefit of humanity.
    Matched MeSH terms: Rubber
  12. Kaida Khalid, W. Mohd. Daud W. Yusoff, Jumiah Hassan
    MyJurnal
    Dielectric properties of natural rubber Hevea brasiliensis latex were measured at frequencies 0.2 to 20 GHz, at temperatures of 2, 15, 25, 35, and 50oC and around 30-98% moisture content. Measurements were done using open-ended coaxial line sensor and automated network analyzer. As expected, results showed that dielectric constant increased with increasing moisture. From 0.2 to 2.6 GHz, the losses were governed by conductive losses but for frequencies greater than 2.6 GHz, these were mainly due to dipolar losses. The former is due to conducting phases in hevea latex, while the latter is mainly governed by the orientation of water molecules. The results were analyzed at 2.6, 10, and 18 GHz, respectively. These were then compared with the values predicted by the dielectric mixture equations recommended by Weiner, Bruggeman and Kraszewski. All the measured values were found to be within the Weiner’s boundaries and close to the upper limit of Weiner’s model. It is also close to the predicted values of Bruggeman’s model with a/b = 0.1. All the models including Kraszewski are suitable for predicting the dielectric properties of hevea latex for frequencies 2.6 to 18 GHz, moisture content 30 to 98% and temperatures 2 to 50oC.
    Matched MeSH terms: Rubber
  13. Dahlan Mohd, Mahathir Mohamed
    MyJurnal
    Polymer blends of 60/40 NR/HDPE were prepared using Brabender PL2000 Plasticorder with 60g capacity. The blends were added with radiation-sensitive natural rubber (NR)-based compatibilizer, known as LENRA. They were irradiated with electron-beam radiation at various doses. The efficacy of the compatibilizer was monitored by measuring various properties of the blends such as physical and dynamic mechanical properties including morphological studies by electron microscopic technique. Early results show that the addition of LENRA improves the properties of the TPNR blends.
    Matched MeSH terms: Rubber
  14. Jamaliah Sharif, Khairul Zaman Mohd Dahlan, Wan Md Zin Wan Yunus
    MyJurnal
    Effects of organoclay concentration on the properties of radiation crosslinked natural rubber (NR)/ ethylene vinyl acetate (EVA)/clay nanocomposites were investigated. The NR/EVA blend with a ratio of 40/60 was melt blended with different concentration of either dodecyl ammonium montmorillonite (DDA-MMT) or dimethyl dihydrogenated tallow quarternary ammonium montmorillonite (C20A). Composite of NR/EVA blend with unmodified clay (Na-MMT) was also prepared for comparison purposes. The composites were irradiated with electron beam (EB) at an optimum irradiation dose. The formation of radiation-induced crosslinking depends on the type and concentration of the organoclay used in the preparation of nanocomposites as measured by gel content. Changes in the interlayer distance of the silicate layers with the increase of organoclay concentration were shown by the XRD results. Variation in the tensile properties of the nanocomposites with the increase of organoclay concentration depends on the formation of crosslinking as well as reinforcement effect of the organoclay. Improvement in thermal stability of the NR/EVA blend was also observed with the presence of organoclay.
    Matched MeSH terms: Rubber
  15. Naji, H.R., Sahri, M.H., Bakar, E.S., Soltani, M., Hamid, H.A.
    ASM Science Journal, 2014;8(1):36-43.
    MyJurnal
    Wood density and types of shrinkage were examined in two rubberwood latex timber clones of rubber (Hevea brasiliensis) namely RRIM 2020 and RRIM 2025, planted at densities of 500, 1000, 1500, and 2000 trees/ha, within a trial plot. The mean wood density showed a low descending trend towards high planting densities in both clones. Wood density was significantly and negatively correlated with planting density. The strength of correlation was moderate. The mean longitudinal shrinkage in both clones and tangential shrinkages in clone RRIM 2020 showed no significant difference among planting densities. The tangential (in RRIM 2025), radial and volumetric shrinkages in both clones decreased from low to high planting densities and the differences were more pronounced between densities of 500 trees/ha and 2000 trees/ha. The magnitudes of correlation between these shrinkages and planting density were low. The regression models indicated that wood density could be more ascribed by planting density followed by volumetric shrinkage. This study exhibited low variations in wood density and shrinkages among clones and the respective planting densities; however, RRIM 2025 was more stable than RRIM 2020.
    Matched MeSH terms: Rubber
  16. Jing CJ, Seman IA, Zakaria L
    Trop Life Sci Res, 2015 Dec;26(2):45-57.
    PMID: 26868709 MyJurnal
    Mating compatibility and restriction analyses of Internal Transcribed Spacer (ITS) regions were performed to determine the relations between Ganoderma boninense, the most common species associated with basal stem rot in oil palm and Ganoderma isolates from infected oil palm, two ornamental palms, sealing wax palm (Cyrtostachys renda) and MacArthur palm (Ptychosperma macarthurii), an isolate from coconut stump (Cocos nucifera), Ganoderma miniatocinctum, Ganoderma zonatum and Ganoderma tornatum. The results showed that G. boninense was compatible with Ganoderma isolates from oil palm, G. miniatocinctum and G. zonatum, Ganoderma isolates from sealing wax palm, MacArthur palm and coconut stump. G. boninense was not compatible with G. tornatum. Therefore, the results suggested that the G. boninense, G. miniatocinctum, G. zonatum, and Ganoderma isolates from oil palm, ornamental palms and coconut stump could represent the same biological species. In performing a restriction analysis of the ITS regions, variations were observed in which five haplotypes were generated from the restriction patterns. An unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis showed that all the Ganoderma isolates were grouped into five primary groups, and the similarity values of the isolates ranged from 97% to 100%. Thus, a restriction analysis of the ITS regions showed that G. boninense and the Ganoderma isolates from other palm hosts were closely related. On the basis of the mating compatibility test and the restriction analysis of the ITS regions performed in this study, a diverse group of Ganoderma species from oil palm and other palm hosts are closely related, except for G. tornatum and Ganoderma isolates from tea and rubber.
    Matched MeSH terms: Rubber
  17. Yeang HY
    Curr Opin Allergy Clin Immunol, 2004 Apr;4(2):99-104.
    PMID: 15021061
    PURPOSE OF REVIEW:
    New allergenic latex proteins have been identified, whereas further information on known latex allergens has emerged in recent years. Although prevalence figures for sensitization to the various latex allergens have been published in several studies in the past, the data have not been collated to facilitate cross-comparison.

    RECENT FINDINGS:
    Salient characteristics of the three most recently identified latex allergens, Hev b 11, 12 and 13 are described, whereas new findings on some of the previously recognized allergens are examined. Hev b 2 is viewed from the standpoint of allergenicity and protein glycosylation, Hev b 4 in relation to its biochemical identity and molecular cloning, Hev b 5 with respect to its recombinant form, and Hev b 6 in connection with conformational IgE epitopes. Reports on sensitization or allergic reaction to purified latex allergens from recent and past work are summarized. The use of latex allergens in latex allergy diagnostics is reviewed and discussed.

    SUMMARY:
    Thirteen latex allergens have been recognized by the International Union of Immunological Societies. Based on the results of published studies, native Hev b 2, recombinant Hev b 5, native or recombinant Hev b 6, native Hev b 13, and possibly native Hev b 4 are the major allergens relevant to latex-sensitized adults. Although there is an increasing tendency to identify and characterize latex allergens largely on the basis of their recombinant forms, not all such recombinant proteins have been fully validated against their native counterparts with respect to clinical significance.
    Matched MeSH terms: Rubber/adverse effects*; Rubber/classification
  18. Mazliah, M., Noraiham, M., Anisah, A.L., Azrul, Y., Hairul, E.A.M., Jeefferie, A.R., et al.
    MyJurnal
    Incineration and disposal of carbon fiber waste from the aircraft industry lead to serious energy consumption and environmental pollution. The use of this waste as reinforcement is a wise approach to appreciate the high performance of the carbon fiber. This study is part of our effort to develop new green rubber foam from recycled carbon fiber prepreg (rCFP) reinforced natural rubber via internal mixer. It is focusing on the effect of different rCFP loading at 1, 3, 5, and 7 parts per hundred rubbers (phr) as reinforcement. The samples were prepared by melt compounding using an internal mixer and expanded via two step heat transfer foaming process. The physical properties of the green rubber foam were characterized and the results were observed to systematically correlate with the impact properties of the foam. The absorbed energy of the foam increases up to 0.3 joules with increasing relative foam density of 0.81 which is associated with the formation of smaller foam cells ~0.68mm and more spherical shape pores.
    Matched MeSH terms: Rubber
  19. Noor, N.M., Ahmad, M.H., Othman, N.H.
    MyJurnal
    The importance of the performance of concrete cannot be neglected since it is the early indicator of its physical and mechanical properties. It became more important when material with different physical properties than normal material such as rubber tire was used as concrete constituent. This paper presented apart of research result conducted on mortar and concrete with crumb rubber. Crumb rubber was replaced at 10%, 15% and 20% as sand replacement by volume. In addition, ordinary Portland cement was added to silica fume at 10% and 15% by weight. The properties measured in this study are air content and workability test. As for workability, superplasticizers were constantly used at 1% dosage for all mortar mixture, and 0.5% to 0.7% for concrete mixture. The air content was set at 4% to 6% and mortar flow test was conducted on a steel plate, shocked 15 times in 15 seconds and concrete slump test was carried out using slump cone equipment. Pressure method was used to measure air content. All mixes were done in a controlled room temperature. Results showed that when CR was added in the mixture segregation was observed in mortar requiring a high dose of superplasticizer to be added to improve the workability while air-modifying agent was used to reduce the mortar air content. In concrete mixture, low dosage of superplasticizers was required for workability and air-entrained agent was injected into the mixture to increase the air content between 4%-6%.
    Matched MeSH terms: Rubber
  20. Shahrol Mohamaddan, Chai Siew Fu, Ahmad Hata Rasit, Siti Zawiah Md Dawal, Keith Case
    MyJurnal
    Congenital talipes equinovarus (CTEV) or clubfoot is a complex deformity of the foot that is characterised by four main deformities; forefoot cavus and adductus, hindfoot varus and ankle equinus. Currently, the Ponseti method is the most general and recognized treatment with a high success rate of over 90%. The treatment involves gentle manipulation and serial casting. However, the casting method could create complications for the patients such as soft-tissue damage and inconvenience in following the treatment schedule especially for those living far away from hospital. The aim of this research is to develop an adjustable corrective device for clubfoot treatment based on the techniques in the Ponseti method and at the same time attempt to eliminate the side-effects. The prototype consists of six adjustable movements from six different mechanisms to correct the four deformities. The prototype was developed using 3D printing method and the main material used is polylactic acid (PLA), rubber, aluminium and cotton fabric with sponge. The total weight of the prototype is around 300 g.
    Matched MeSH terms: Rubber
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