Displaying all 12 publications

  1. Hamzah, E., Kanniah, M., Harun, M.
    The microstructure, tensile fracture and creep fracture of as-cast beta phase contained γ-TiAl with nominal composition of Ti-48Al-4Cr (at.%) was investigated. The effect of beta phase on tensile and creep strength was determined from fracture analysis. Tensile test were performed at room temperature whereas constant load tensile creep test were performed at temperature 800 0 C and initial stress of 150MPa. Initial as-cast microstructure, microstructure and fracture surface after tensile and creep test were examined using scanning electron microscopy technique. Analysis shows brittle fracture after room temperature tensile test whereas ductile fracture after high temperature creep test. The role of beta phase was discussed. It is concluded that beta phase is sensitive to temperature and detrimental at both room and high temperature.
  2. Pahlevanzadeh F, Bakhsheshi-Rad HR, Hamzah E
    J Mech Behav Biomed Mater, 2018 06;82:257-267.
    PMID: 29627737 DOI: 10.1016/j.jmbbm.2018.03.016
    In this study, a bone cement consisting of poly methyl methacrylate (PMMA)-poly caprolactone (PCL)-fluorapatite (FA)-graphene oxide (GO) was synthesized as bone filler for application in orthopedic surgeries. The FA and GO particulates were homogenously distributed in the PMMA-PCL polymer matrix and no defects and agglomeration were found in the PMMA-PCL/FA/GO bone cement. The in-vitro bioactivity result exhibited that addition of FA and GO to the polymer cement (PMMA-PCL) improved the apatite formation ability on the surface of polymer. The results also showed that addition of FA to the polymer bone cement escalated the compressive strength and elastic modulus while reducing elongation to 8 ± 2%. However, after addition of GO into the PMMA-PCL/FA bone cement, both compressive strength and elongation considerably increased to 101 ± 5 MPa and 35 ± 6%, respectively. Furthermore, tensile tests exhibited that inclusion of GO was favorable in improving the tensile modulus, UTS and elongation of the PMMA-PCL/FA bone cement. The cytotoxicity test pointed out that MG63 osteoblast cells viability increased to 279 ± 15% after addition of FA and GO to the PMMA-PCL polymer bone cement. The DAPI (4',6-diamidino-2-phenylindole) staining demonstrated better spreading and attachment of MG63 cells on PMMA-PCL/FA/GO surface compared to the PMMA-PCL bone cements. These results confirm the suitable mechanical properties and favorable bioactivity along with high cells viability of PMMA-PCL/FA/GO bone cement, indicating its potentials for orthopedic applications.
  3. Thongkhamcharoen R, Breaden K, Agar M, Hamzah E
    Indian J Palliat Care, 2012 May;18(2):128-33.
    PMID: 23093829 DOI: 10.4103/0973-1075.100835
    Managing dyspnea at home is a challenging task. Although a competent palliative home care team can assist a patient to live at home with better pain control, dyspnea is usually not as well managed. In the Asian context, there are few research studies in dyspnea management in palliative home care. This paper aims to illustrate the cultural context that has an impact on dyspnea management at home and the assessment and management of dyspnea in a community palliative care setting in Malaysia. This paper reports on a study of 5 dyspneic patients suffering from both cancer-related and non-cancer-related dyspnea. Its focus is on a unique Asian cultural belief system that affects communication about prognosis and the role of family in palliative home care. In addition, this paper also describes dyspnea assessment, the barriers to morphine use, benzodiazepine prescription, oxygen therapy, and nonpharmacologic intervention in this center.
  4. Sing NB, Mostavan A, Hamzah E, Mantovani D, Hermawan H
    J Biomed Mater Res B Appl Biomater, 2015 Apr;103(3):572-7.
    PMID: 24954069 DOI: 10.1002/jbm.b.33242
    This article reports a degradation study that was done on stent prototypes made of biodegradable Fe35Mn alloy in a simulated human coronary arterial condition. The stent degradation was observed for a short-term period from 0.5 to 168 h, which simulates the early period of stenting procedure. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to quantify degradation rate and surface property of the stents. Results showed that signs of degradation were visible on both crimped and expanded stents after 1 h of test, mostly located on the stent's curvatures. The degradation rate of stent was higher compared to that of the original alloy, indicating the surface altering effect of stent fabrication processing to degradation. A single oxide layer was formed and detected as a porous structure with capacitive behavior. Expanded stents exhibited lower polarization resistance compared to the nonexpanded ones, indicating the cold work effect of expansion procedure to degradation.
  5. Saud SN, Hamzah E, Bakhsheshi-Rad HR, Abubakar T
    Scanning, 2017;2017:1789454.
    PMID: 29109802 DOI: 10.1155/2017/1789454
    The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shape memory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0 wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0 wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery), and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.
  6. Bakhsheshi-Rad HR, Hamzah E, Kasiri-Asgarani M, Jabbarzare S, Iqbal N, Abdul Kadir MR
    Mater Sci Eng C Mater Biol Appl, 2016 Mar;60:526-537.
    PMID: 26706560 DOI: 10.1016/j.msec.2015.11.057
    The present study addressed the synthesis of a bi-layered nanostructured fluorine-doped hydroxyapatite (nFHA)/polycaprolactone (PCL) coating on Mg-2Zn-3Ce alloy via a combination of electrodeposition (ED) and dip-coating methods. The nFHA/PCL composite coating is composed of a thick (70-80 μm) and porous layer of PCL that uniformly covered the thin nFHA film (8-10 μm) with nanoneedle-like microstructure and crystallite size of around 70-90 nm. Electrochemical measurements showed that the nFHA/PCL composite coating presented a high corrosion resistance (R(p)=2.9×10(3) kΩ cm(2)) and provided sufficient protection for a Mg substrate against galvanic corrosion. The mechanical integrity of the nFHA/PCL composite coatings immersed in SBF for 10 days showed higher compressive strength (34% higher) compared with the uncoated samples, indicating that composite coatings can delay the loss of compressive strength of the Mg alloy. The nFHA/PCL coating indicted better bonding strength (6.9 MPa) compared to PCL coating (2.2 MPa). Immersion tests showed that nFHA/PCL composite-coated alloy experienced much milder corrosion attack and more nucleation sites for apatite compared with the PCL coated and uncoated samples. The bi-layered nFHA/PCL coating can be a good alternative method for the control of corrosion degradation of biodegradable Mg alloy for implant applications.
  7. Saud SN, Hosseinian S R, Bakhsheshi-Rad HR, Yaghoubidoust F, Iqbal N, Hamzah E, et al.
    Mater Sci Eng C Mater Biol Appl, 2016 Nov 01;68:687-694.
    PMID: 27524069 DOI: 10.1016/j.msec.2016.06.048
    In the present work, the microstructure, corrosion, and bioactivity of graphene oxide (GO) coating on the laser-modified and -unmodified surfaces of TiNb shape memory alloys (SMAs) were investigated. The surface morphology and chemical composition was examined using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The surface modification was carried out via a femtosecond laser with the aim to increase the surface roughness, and thus increase the adhesion property. FE-SEM analysis of the laser-treated Ti-30at.% Nb revealed the increase in surface roughness and oxygen/nitrogen containing groups on the Ti-30at.% Nb surface after being surface modified via a femtosecond laser. Furthermore, the thickness of GO was increased from 35μm to 45μm after the surface was modified. Potentiodynamic polarisation and electrochemical impedance spectroscopy studies revealed that both the GO and laser/GO-coated samples exhibited higher corrosion resistance than that of the uncoated TiNb SMA sample. However, the laser/GO-coated sample presented the highest corrosion resistance in SBF at 37°C. In addition, during soaking in the simulated body fluid (SBF), both the GO and laser/GO coating improved the formation of apatite layer. Based on the bioactivity results, the GO coating exhibited a remarkable antibacterial activity against gram-negative bacteria compared with the uncoated. In conclusion, the present results indicate that Ti-30at.% Nb SMAs may be promising alternatives to NiTi for certain biomedical applications.
  8. Bakhsheshi-Rad HR, Hamzah E, Low HT, Kasiri-Asgarani M, Farahany S, Akbari E, et al.
    Mater Sci Eng C Mater Biol Appl, 2017 Apr 01;73:215-219.
    PMID: 28183601 DOI: 10.1016/j.msec.2016.11.138
    In this work, binary Zn-0.5Al and ternary Zn-0.5Al-xMg alloys with various Mg contents were investigated as biodegradable materials for implant applications. Compared with Zn-0.5Al (single phase), Zn-0.5Al-xMg alloys consisted of the α-Zn and Mg2(Zn, Al)11 with a fine lamellar structure. The results also revealed that ternary Zn-Al-Mg alloys presented higher micro-hardness value, tensile strength and corrosion resistance compared to the binary Zn-Al alloy. In addition, the tensile strength and corrosion resistance increased with increasing the Mg content in ternary alloys. The immersion tests also indicated that the corrosion rates in the following order Zn-0.5Al-0.5Mg
  9. Dayaghi E, Bakhsheshi-Rad HR, Hamzah E, Akhavan-Farid A, Ismail AF, Aziz M, et al.
    Mater Sci Eng C Mater Biol Appl, 2019 Sep;102:53-65.
    PMID: 31147024 DOI: 10.1016/j.msec.2019.04.010
    Recently, porous magnesium and its alloys are receiving great consideration as biocompatible and biodegradable scaffolds for bone tissue engineering application. However, they presented poor antibacterial performance and corrosion resistance which limited their clinical applications. In this study, Mg-Zn (MZ) scaffold containing different concentrations of tetracycline (MZ-xTC, x = 1, 5 and 10%) were fabricated by space holder technique to meet the desirable antibacterial activity and corrosion resistance properties. The MZ-TC contains total porosity of 63-65% with pore sizes in the range of 600-800 μm in order to accommodate bone cells. The MZ scaffold presented higher compressive strength and corrosion resistance compared to pure Mg scaffold. However, tetracycline incorporation has less significant effect on the mechanical and corrosion properties of the scaffolds. Moreover, MZ-xTC scaffolds drug release profiles show an initial immediate release which is followed by more stable release patterns. The bioactivity test reveals that the MZ-xTC scaffolds are capable of developing the formation of HA layers in simulated body fluid (SBF). Next, Staphylococcus aureus and Escherichia coli bacteria were utilized to assess the antimicrobial activity of the MZ-xTC scaffolds. The findings indicate that those scaffolds that incorporate a high level concentration of tetracycline are tougher against bacterial organization than MZ scaffolds. However, the MTT assay demonstrates that the MZ scaffolds containing 1 to 5% tetracycline are more effective to sustain cell viability, whereas MZ-10TC shows some toxicity. The alkaline phosphatase (ALP) activity of the MZ-(1-5)TC was considerably higher than that of MZ-10TC on the 3 and 7 days, implying higher osteoblastic differentiation. All the findings suggest that the MZ-xTC scaffolds containing 1 to 5% tetracycline is a promising candidate for bone tissue healing due to excellent antibacterial activity and biocompatibility.
  10. Bakhsheshi-Rad HR, Hamzah E, Ying WS, Razzaghi M, Sharif S, Ismail AF, et al.
    Materials (Basel), 2021 Apr 12;14(8).
    PMID: 33921460 DOI: 10.3390/ma14081930
    Magnesium has been recognized as a groundbreaking biodegradable biomaterial for implant applications, but its use is limited because it degrades too quickly in physiological solutions. This paper describes the research on the influence of polycaprolactone (PCL)/chitosan (CS)/zinc oxide (ZnO) composite coating (PCL/CS/ZnO) on the corrosion resistance and antibacterial activity of magnesium. The PCL/CS film presented a porous structure with thickness of about 40-50 μm, while after incorporation of ZnO into the PCL/CS, a homogenous film without pores and defects was attained. The ZnO embedded in PCL/CS enhanced corrosion resistance by preventing corrosive ions diffusion in the magnesium substrate. The corrosion, antibacterial, and cell interaction mechanism of the PCL/CS/ZnO composite coating is discussed in this study. In vitro cell culture revealed that the PCL/CS coating with low loaded ZnO significantly improved cytocompatibility, but coatings with high loaded ZnO were able to induce some cytotoxicity osteoblastic cells. It was also found that enhanced antibacterial activity of the PCL/CS/ZnO coating against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, while less significant antibacterial activity was detected for uncoated Mg and PCL/CS coating. Based on the results, the PCL/CS coatings loaded with low ZnO content may be recommended as a candidate material for biodegradable Mg-based orthopedic implant applications.
  11. Yong ASJ, Lim YH, Cheong MWL, Hamzah E, Teoh SL
    Eur J Health Econ, 2021 Dec 02.
    PMID: 34853930 DOI: 10.1007/s10198-021-01407-9
    BACKGROUND: Understanding patient preferences in cancer management is essential for shared decision-making. Patient or societal willingness-to-pay (WTP) for desired outcomes in cancer management represents their preferences and values of these outcomes.

    OBJECTIVE: The aim of this systematic review is to critically evaluate how current literature has addressed WTP in relation to cancer treatment and achievement of outcomes.

    METHODS: Seven databases were searched from inception until 2 March 2021 to include studies with primary data of WTP values for cancer treatments or achievement of outcomes that were elicited using stated preference methods.

    RESULTS: Fifty-four studies were included in this review. All studies were published after year 2000 and more than 90% of the studies were conducted in high-income countries. Sample size of the studies ranged from 35 to 2040, with patient being the most studied population. There was a near even distribution between studies using contingent valuation and discrete choice experiment. Based on the included studies, the highest WTP values were for a quality-adjusted life year (QALY) ($11,498-$589,822), followed by 1-year survival ($3-$198,576), quality of life (QoL) improvement ($5531-$139,499), and pain reduction ($79-$94,662). Current empirical evidence suggested that improvement in QoL and pain reduction had comparable weights to survival in cancer management.

    CONCLUSION: This systematic review provides a summary on stated preference studies that elicited patient preferences via WTP and summarised their respective values. Respondents in this review had comparable WTP for 1-year survival and QoL, suggesting that improvement in QoL should be emphasised together with survival in cancer management.

  12. Lin CP, Boufkhed S, Kizawa Y, Mori M, Hamzah E, Aggarwal G, et al.
    Am J Hosp Palliat Care, 2021 Jul;38(7):861-868.
    PMID: 33789503 DOI: 10.1177/10499091211002797
    BACKGROUND: Hospice and palliative care services provision for COVID-19 patients is crucial to improve their life quality. There is limited evidence on COVID-19 preparedness of such services in the Asia-Pacific region.

    AIM: To evaluate the preparedness and capacity of hospice and palliative care services in the Asia-Pacific region to respond to the COVID-19 pandemic.

    METHOD: An online cross-sectional survey was developed based on methodology guidance. Asia-Pacific Hospice and Palliative Care Network subscribers (n = 1551) and organizational members (n = 185) were emailed. Descriptive analysis was undertaken.

    RESULTS: Ninety-seven respondents completed the survey. Around half of services were hospital-based (n = 47, 48%), and public-funded (n = 46, 47%). Half of services reported to have confirmed cases (n = 47, 49%) and the majority of the confirmed cases were patients (n = 28, 61%). Staff perceived moderate risk of being infected by COVID-19 (median: 7/10). > 85% of respondents reported they had up-to-date contact list for staff and patients, one-third revealed challenges to keep record of relatives who visited the services (n = 30, 31%), and of patients visited in communities (n = 29, 30%). Majority of services (60%) obtained adequate resources for infection control except face mask. More than half had no guidance on Do Not Resuscitate orders (n = 59, 66%) or on bereavement care for family members (n = 44, 51%).

    CONCLUSION: Recommendations to strengthen the preparedness of palliative care services include: 1) improving the access to face mask; 2) acquiring stress management protocols for staff when unavailable; 3) reinforcing the contact tracing system for relatives and visits in the community and 4) developing guidance on patient and family care during patient's dying trajectory.

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