Displaying publications 1 - 20 of 23 in total

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  1. Naznin, M, Abdul Rahman, S., Ariff, O., Ahmad Mansur, M, Kasule, O.H.
    MyJurnal
    Background: The approach to the teaching of ethics and professionalism in the Faculty of Medicine (FM) of International Islamic University Malaysia (IIUM) is unique. A specifically designed package is incorporated designated as the Islamic Input into the Medical Programme (IIMP). The IIMP spans over the entire 5 years of the medical programme. In the Faculty of Allied Health Sciences (FAHS) students do not go through a similar Islamic Input module but exposed to ethical issues specific to health sciences. Method: The aim of this study is to assess the impact of the teaching of ethics through the IIMP. A cross-sectional study was conducted in medical and allied health sciences faculties of IIUM. In total 259 students volunteered and were allocated to 4 groups, Years 2 and 5 students of FM and Years 2 and 4 of FAHS. A set of questionnaire consisting of 20 vignettes related to medical ethics was distributed to all students. An independent t-test was used to compare the mean total scores between the groups. Results: A significant difference (p < 0.05) was seen between the mean total scores for the Year 2 and Year 5 students of FM; Year 2 students of FM and Year 2 students of FAHS; and between the Year 5 students of FM and Year 4 students of FAHS. Also there was significant difference between the two medical and allied health sciences groups as a whole. Discussion: This study suggests that the IIMP of the IIUM has a positive impact on the medical students when dealing with ethical issues. The Year 5 medical students were expected to have obtained a higher mean total score. The probable reason for the lower mean total score include the teaching-learning approach utilized which is mainly lecture with minimal small group approach. Also the allocation of marks for medical ethics in summative assessment in the IIUM medical curriculum is minimal compared to the core medical subjects which would have some influence on the weight given by students. Conclusion: The Medical Faculty of IIUM believes that the approach to the teaching of medical ethics by incorporating the Islamic Input module is effective, practical and relevant. However the teaching-learning method and the assessment will have to be re-addressed to achieve greater impact.
  2. Moy FM, Abdul Rahman S
    Malays J Nutr, 2002 Mar;8(1):63-73.
    PMID: 22692440 MyJurnal
    A cross sectional study on Type 2 diabetes patients seeking treatment in the Primary Health Care outpatient clinic of the University Malaya Medical Centre, Kuala Lumpur was undertaken. Two hundred and thirty-three subjects participated. They were asked questions on biodata and dietary intake using face-to-face interview techniques. Dietary intake was assessed using the 24-hour dietary recall. Anthropometric measurements including weight and height were taken and Body Mass Index (BMI) was computed to establish the extent of obesity. Of the 196 subjects, 66.8% were overweight (BMI ≥25 kg/m2) with 15.8% obese (BMI ≥30 kg/m2). The mean BMI of males and females were 25.9±4.3 kg/m2 and 27.2±4.7 kg/m2 respectively. The findings from the dietary survey showed that the mean energy intake of the subjects only achieved about 72% of the Recommended Daily Allowance (RDA) for Malaysia while protein intake of all subjects was adequate. The macronutreint contribution to the total calorie was consistent with the recommendation of the Malaysian Diabetic Association for a healthy diet for diabetes patients. The male subjects were found to meet the RDA requirements for all nutrients while the female subjects did not have sufficient intake of calcium, vitamin A and niacin. No consistent pattern in energy and nutrient intake was observed among different age groups. On the other hand, the Malay subjects seemed to have lower energy and all nutrient intake (except vitamin A and vitamin C) compared to the Chinese and Indian subjects. The Indian subjects seemed to have the highest intake of calcium compared to the others. Advice needs to be given to those who did not have adequate nutrient intake as well as those who need to reduce their weight.

    Study site: Primary health care clinic, University Malaya Medical Centre (UMMC)
  3. Shaikh Abdul Rahman S, Aziz Z
    J Clin Pharm Ther, 2020 Oct;45(5):946-958.
    PMID: 31925959 DOI: 10.1111/jcpt.13106
    WHAT IS KNOWN AND OBJECTIVE: Complementary and alternative medicine (CAM) is widely used worldwide for health maintenance, disease prevention and treatment. The objective of the study was to identify adverse drug reactions (ADR) associated with the use of CAM in Malaysia and factors which are associated with the more serious reactions.

    METHODS: All ADR associated with the use of CAM products (including health supplements) submitted to the Malaysian Centre for ADR Monitoring, National Pharmaceutical Regulatory Agency over a 15-year period were reviewed and analysed. Multivariate logistic regression analysis was performed to identify predictors of serious ADR.

    RESULTS AND DISCUSSION: From a total of 74 997 reports in the database, 930 (1.2%) involved CAM products, and 242 (26%) were serious with 36 deaths. About a third of the reports involved used CAM products for health maintenance. Most (78.1%) of the ADR reports implicated unregistered products with 16.7% confirmed to contain adulterants which were mainly dexamethasone. Of the 930 reports, the ADR involved skin and appendages disorders (18.4%) followed by liver and biliary system disorders (13.7%). The odds of someone experiencing serious ADR increased if the CAM products were used for chronic illnesses (odds ratio [OR] 1.99, confidence interval [CI] 1.46-2.71), having concurrent diseases (OR 1.51, CI 1.04-2.19) and taking concurrent drugs (OR 1.44, CI 1.03-2.02).

    WHAT IS NEW AND CONCLUSIONS: The prevalence of serious ADR associated with CAM products is high. Factors identified with serious ADR included ethnicity, CAM users with pre-existing diseases, use of CAM for chronic illnesses and concomitant use of CAM products with other drugs. The findings could be useful for planning strategies to institute measures to ensure safe use of CAM products.

  4. Chong SK, Dee CF, Abdul Rahman S
    Nanoscale Res Lett, 2013;8(1):174.
    PMID: 23590803 DOI: 10.1186/1556-276X-8-174
    Silicon/zinc oxide (Si/ZnO) core-shell nanowires (NWs) were prepared on a p-type Si(111) substrate using a two-step growth process. First, indium seed-coated Si NWs (In/Si NWs) were synthesized using a plasma-assisted hot-wire chemical vapor deposition technique. This was then followed by the growth of a ZnO nanostructure shell layer using a vapor transport and condensation method. By varying the ZnO growth time from 0.5 to 2 h, different morphologies of ZnO nanostructures, such as ZnO nanoparticles, ZnO shell layer, and ZnO nanorods were grown on the In/Si NWs. The In seeds were believed to act as centers to attract the ZnO molecule vapors, further inducing the lateral growth of ZnO nanorods from the Si/ZnO core-shell NWs via a vapor-liquid-solid mechanism. The ZnO nanorods had a tendency to grow in the direction of [0001] as indicated by X-ray diffraction and high resolution transmission electron microscopy analyses. We showed that the Si/ZnO core-shell NWs exhibit a broad visible emission ranging from 400 to 750 nm due to the combination of emissions from oxygen vacancies in ZnO and In2O3 structures and nanocrystallite Si on the Si NWs. The hierarchical growth of straight ZnO nanorods on the core-shell NWs eventually reduced the defect (green) emission and enhanced the near band edge (ultraviolet) emission of the ZnO.
  5. Bin Abdul Rahman S, Tan Boon Ann, Subbiah M, Loh Sow Khin, Baker Y
    Stud Fam Plann, 1974 May;5(5):158-9.
    PMID: 4828069 DOI: 10.2307/1965315
  6. Aris N, Abdul Rahman S, Shahidan N
    Sains Malaysiana, 2009;38(6):953–958.
    The prevalence of anaemia and nutritional status was evaluated among 88 Malay elderly (20 men and 68 women) aged 60 to 85 years (mean age 69.8 ± 6.0 years) from four villages in Rembau district, Negeri Sembilan. In addition, the relationship between hemoglobin with nutrient intake, cognitive and functional status of the elderly were also investigated. Subjects were interviewed to obtain information on demographic and nutrient intake. Cognitive status was assessed using Elderly Cognitive Assessment Questionnaire (ECAQ) while functional status was measured using Instrumental Activity Daily Living (IADL) and hand grip measurement. Hemoglobin level was determined using HemoCue method. The findings indicated that the prevalence of anaemia was 22.7%. Prevalence of anaemia for male subject was 30.0% with mean of hemoglobin as 11.7 ± 1.0 g/dL while 20.6% of female subject was anaemic with mean of hemoglobin was 11.2 ± 0.5 g/dL. As much as 21.6% of the subjects have cognitive impairment with the prevalence is high in old-old age group (57.9%) compared to the young-old age group (11.6%). Results from functional assessment showed that mean for IADL score as 11 ± 3. The IADL score was lower in old-old age group (9 ± 4) compared to the young-old age group (12 ± 2). For hand grip measurement, overall mean was 16.8 ± 8.7 kg (14.2 ± 8.4 kg for old-old age group and 17.6 ± 8.7 kg for young-old age group). Nutrient analysis showed that the mean calorie intake for men (1310 ± 448 kcal/day) and women (1180 ± 300 kcal) were lower than the RNI. However, only intakes of iron, niacin and vitamin A achieved the Malaysian Recommended Nutrient Intake (RNI). Correlation between hemoglobin and nutrients was only showed with calorie intake (r=0.486, p=0.048) and not with other nutrients. Besides that, there was no correlation between hemoglobin with ECAQ and IADL scores but hemoglobin was correlated with hand grip strength (r=0.265, p=0.013). As a conclusion, 22.7% case of anaemia was reported in this study. However, correlations were only formed between hemoglobin with calorie intake and hemoglobin with hand grip. Anaemia in elderly increases the inability of the elderly to live independently.
    Keywords: Anemia; cognitive status; elderly; functional status
  7. Sivanganam S, Abdullah MF, Abdul Rahman S
    Case Rep Oncol, 2022;15(3):848-853.
    PMID: 36825104 DOI: 10.1159/000526698
    Fanconi anaemia (FA) is an autosomal recessive inherited disease that renders patients susceptible to congenital anomalies, bone marrow failures, leukaemia, and solid malignancies. FA is caused by the loss of function of at least one gene in the FA/BRCA biological pathway, which is involved in DNA repair. Patients with FA have an increased risk of developing head and neck cancer, particularly oral squamous cell carcinoma (SCC). Due to susceptibility of head and neck cancer at a very young age, relatively poor survival rate, low tolerance to oncologic interventions, and complexity of treatments, strict follow-up is mandatory to detect any changes or recurrence of SCC in the head and neck region in FA patients. Surgery is the mainstay of treatment, but adjuvant therapy should be instituted when needed. This short report describes a rare case of lower lip SCC in FA and its management. It also highlights the impact of the COVID-19 pandemic on healthcare practices.
  8. Abdullah MF, Abdul Rahman S, Fauzi FA
    Cureus, 2023 Sep;15(9):e44832.
    PMID: 37809267 DOI: 10.7759/cureus.44832
    Oral manifestations may be the earliest indicators of HIV infection as it has strong association with oral candidiasis, hairy leukoplakia, linear gingival erythema, necrotizing ulcerative gingivitis, necrotizing ulcerative periodontitis, Kaposi sarcoma, and lymphoma. Other conditions such as diffuse infiltrative lymphocytosis syndrome, benign lymphoepithelial cyst, and salivary gland neoplasm have also been reported in HIV patients. Ranulas are caused by salivary leakage from the sublingual gland as a result of ductal obstruction or trauma. At the present time, there is no clear evidence of a link between plunging ranula and HIV. The authors described a case of plunging ranula of the right floor of the mouth with a concurrent perioperative diagnosis of HIV. Surgical excision of ranula and associated salivary glands via submandibular and intraoral approach was successfully done with no recurrence over a period of one year. This case also highlights the importance of taking a thorough clinical history from patients and always practicing universal precautions, especially during surgical interventions.
  9. Fauzi FA, Abdullah MF, Abdul Rahman S
    Cureus, 2024 Feb;16(2):e54715.
    PMID: 38523935 DOI: 10.7759/cureus.54715
    Male urethral stricture is scarring of the urethral tissue that narrows the urethral lumen causing reduced urinary flow. Urethral reconstruction or substitution urethroplasty using oral mucosa graft, especially from the buccal mucosa, is one of the most widely known techniques to manage urethral stricture. However, studies using bilateral buccal mucosa are still limited. Therefore, this study aims to report our experience and technique of bilateral buccal mucosa grafting for urethroplasty. The authors described a 66-year-old man with long-segment urethral stricture that was successfully treated with urethral reconstruction harvested from bilateral buccal mucosa.
  10. Banihashemian SM, Periasamy V, Boon Tong G, Abdul Rahman S
    PLoS One, 2016;11(3):e0149488.
    PMID: 26999445 DOI: 10.1371/journal.pone.0149488
    Studying the effect of a magnetic field on oligonucleotide DNA can provide a novel DNA manipulation technique for potential application in bioengineering and medicine. In this work, the optical and electrochemical response of a 100 bases oligonucleotides DNA, cytosine-guanine (CG100), is investigated via exposure to different magnetic fields (250, 500, 750, and 1000 mT). As a result of the optical response of CG100 to the magnetic field, the ultra-violet-visible spectrum indicated a slight variation in the band gap of CG100 of about 0.3 eV. Raman spectroscopy showed a significant deviation in hydrogen and phosphate bonds' vibration after exposure to the magnetic field. Oligonucleotide DNA mobility was investigated in the external electric field using the gel electrophoresis technique, which revealed a small decrease in the migration of CG100 after exposure to the magnetic field.
  11. Khanis NH, Ritikos R, Ahmad Kamal SA, Abdul Rahman S
    Materials (Basel), 2017 Jan 24;10(2).
    PMID: 28772460 DOI: 10.3390/ma10020102
    Nanostructured hydrogenated carbon nitride (CNx:H) thin films were synthesized on a crystal silicon substrate at low deposition temperature by radio-frequency plasma-enhanced chemical vapor deposition (PECVD). Methane and nitrogen were the precursor gases used in this deposition process. The effects of N₂ to the total gas flow rate ratio on the formation of CNx:H nanostructures were investigated. Field-emission scanning electron microscopy (FESEM), Auger electron spectroscopy (AES), Raman scattering, and Fourier transform of infrared spectroscopies (FTIR) were used to characterize the films. The atomic nitrogen to carbon ratio and sp² bonds in the film structure showed a strong influence on its growth rate, and its overall structure is strongly influenced by even small changes in the N₂:(N₂ + CH₄) ratio. The formation of fibrous CNx:H nanorod structures occurs at ratios of 0.7 and 0.75, which also shows improved surface hydrophobic characteristic. Analysis showed that significant presence of isonitrile bonds in a more ordered film structure were important criteria contributing to the formation of vertically-aligned nanorods. The hydrophobicity of the CNx:H surface improved with the enhancement in the vertical alignment and uniformity in the distribution of the fibrous nanorod structures.
  12. Salin N, Ishak AK, Abdul Rahman S, Ali M, Nawawi HM, Said MS, et al.
    Med J Malaysia, 2008 Jul;63 Suppl A:67-8.
    PMID: 19024987
    Bone formation is an active process whereby osteoblasts are found on the surface of the newly formed bone. Adhesion to extracellular matrix is essential for the development of bone however not all surfaces are suitable for osteoblast adhesion and don't support osteoblastic functions. The objective of this study was to test the suitability of a collagen based microcarrier which would support osteoblastic functions.
  13. Chin FW, Chan SC, Abdul Rahman S, Noor Akmal S, Rosli R
    Breast J, 2016 Jan-Feb;22(1):54-62.
    PMID: 26510986 DOI: 10.1111/tbj.12518
    The cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6) is an enzyme that is predominantly involved in the metabolism of tamoxifen. Genetic polymorphisms of the CYP2D6 gene may contribute to inter-individual variability in tamoxifen metabolism, which leads to the differences in clinical response to tamoxifen among breast cancer patients. In Malaysia, the knowledge on CYP2D6 genetic polymorphisms as well as metabolizer status in Malaysian breast cancer patients remains unknown. Hence, this study aimed to comprehensively identify CYP2D6 genetic polymorphisms among 80 Malaysian breast cancer patients. The genetic polymorphisms of all the 9 exons of CYP2D6 gene were identified using high-resolution melting analysis and confirmed by DNA sequencing. Seven CYP2D6 alleles consisting of CYP2D6*1, CYP2D6*2, CYP2D6*4, CYP2D6*10, CYP2D6*39, CYP2D6*49, and CYP2D6*75 were identified in this study. Among these alleles, CYP2D6*10 is the most common allele in both Malaysian Malay (54.8%) and Chinese (71.4%) breast cancer patients, whereas CYP2D6*4 in Malaysian Indian (28.6%) breast cancer patients. In relation to CYP2D6 genotype, CYP2D6*10/*10 is more frequently observed in both Malaysian Malay (28.9%) and Chinese (57.1%) breast cancer patients, whereas CYP2D6*4/*10 is more frequently observed in Malaysian Indian (42.8%) breast cancer patients. In terms of CYP2D6 phenotype, 61.5% of Malaysian Malay breast cancer patients are predicted as extensive metabolizers in which they are most likely to respond well to tamoxifen therapy. However, 57.1% of Chinese as well as Indian breast cancer patients are predicted as intermediate metabolizers and they are less likely to gain optimal benefit from the tamoxifen therapy. This is the first report of CYP2D6 genetic polymorphisms and phenotypes in Malaysian breast cancer patients for different ethnicities. These data may aid clinicians in selecting an optimal drug therapy for Malaysian breast cancer patients, hence improve the clinical outcome of the patients.
  14. Wan Jusoh WZA, Abdul Rahman S, Ahmad AL, Mohd Mokhtar N
    Data Brief, 2019 Jun;24:103910.
    PMID: 31193576 DOI: 10.1016/j.dib.2019.103910
    This paper focus to examine the best molecular interaction between Polyamide Thin Film Composite (PA TFC) layers with different properties of the support membrane. The support membrane of Nylon 66 (N66) and Polyvinylidene fluoride (PVDF) was chosen to represent the hydrophilic and hydrophobic model respectively in the Molecular Dynamic (MD) simulation. The Condensed-Phase Optimized Molecular Potential for Atomistic Simulation Studies (COMPASS) force field was used with the total simulation runs were set 1000 picoseconds run production ensembles. The temperature and pressure set for both ensembles were 298 K and 1 atm respectively. The validity of our model densities data was check and calculated where the deviation must be less than 6%. The comparison between hydrophobic and hydrophilic of the support membrane data was examined by the distance and magnitude of intensity of the Radial Distribution Function (RDF's) trends.
  15. Ramli N, Abdul Rahman S, Hassan O, Mohd Yatim A, Said M, Lim LS, et al.
    Malays J Nutr, 2000 Mar;6(1):55-63.
    PMID: 22692392
    Thirty-two samples of chocolate products were analysed by HPLC for caffeine and theobromine contents. Defatted residues of samples were extracted with 80% aqueous acetone. After extraction into boiling water, the methylxanthines were identified and quantified with the use of μ-Bondapak column and mobile phase of methanol:water:acetic acid (20:79:1). Levels of caffein and theobromine in 32 samples of chocolate products averaged 0.62-1.14 mg/g and 0.026-0.153 mg/g respectively. Mean values for theobromine and caffeine content for chocolate coating were 0.82 and 0.07 mg/g respectively. The chocolate coating made from fat substitute had theobromine and caffeine levels ranging from 0.36-0.70 mg/g and 0.027-0.061 mg/g respectively, with mean values of 0.49 mg theobromine/g and 0.039 mg caffeine/g. In local chocolate, the mean theobromine and caffeine levels respectively were 0.72 mg/g and 0.04 mg/g in milk chocolate, and 0.85 mg/g and 0.06 mg/g in dark chocolate. Meanwhile, for imported chocolate, the mean theobromine and caffeine levels respectively were 1.05 mg/g and 0.12 mg/g in dark chocolate; 0.76 mg/g and 0.04 mg/g in milk chocolate; and 0.74 mg/g and 0.03 mg/g in white chocolate. Compared with the local chocolates, imported chocolates had higher levels of theobromine and caffeine at 1.141 mg/g and 0.1533mg/g. The average theobromine and caffeine concentrations in local chocolate were 0.082mg/g and 0.066mg/g. Theobromine concentration in chocolate samples is within the range of 0.62mg/g-1.141mg/g and the range of caffeine concentration is 0.026mg/g-0.153mg/g respectively. Bittersweet chocolates were found to have higher theobromine and caffeine concentrations than normal sweet chocolates and milk chocolates.
  16. Tengku Shaeran TA, Shaari R, Abdul Rahman S, Alam MK, Muhamad Husin A
    J Oral Biol Craniofac Res, 2017 Jan-Apr;7(1):7-12.
    PMID: 28316914 DOI: 10.1016/j.jobcr.2016.10.007
    BACKGROUND: Bilateral sagittal split osteotomy (BSSO) is the most versatile procedure and adopted by many surgeons to relocate the mandible in patients having mandibular prognathism (MP). Injury to the inferior alveolar nerve (IAN) and unfavorable splits are two surgical complications of BSSO which are associated with mandibular morphology. Uses of cone beam computed tomography (CBCT) in providing 3-D images has gained a wider acceptance in surgical field nowadays. Its advantages are including reduced cost, lesser radiation dose and smaller physical footprint comparing to the conventional computed tomography.

    PURPOSE: This study aims to identify the differences in morphology of prognathic and non-prognathic mandible at BSSO sites using cone beam computed tomography images.

    METHODS: This retrospective study involved 51 CBCT images of patients having mandibular prognathism and without mandibular prognathism. The latter group made up from patients with Class I skeletal pattern. Samples were taken using purposive sampling method from two clinical centers.

    RESULT: Prognathic mandible has higher lingula level, superiorly and buccally placed inferior alveolar nerve canal at distal second molar, thinner mediolateral width of ramus at anterior and posterior part and thinner anteroposterior width of the ramus.

    CONCLUSION: Morphology of mandible in patients with mandibular prognathism (MP) was significantly different from patients without mandibular prognathism (WMP) for most of the parameters. The high risk parameters may be highlighted to the patients using cone beam computed tomography images.
  17. Abdul Rahman S, Jeffree MS, Kamaludin F, Din IA, Yusof M, Ahmed K
    J Immigr Minor Health, 2018 Oct;20(5):1294-1297.
    PMID: 29159485 DOI: 10.1007/s10903-017-0674-5
    In February 2012, a district health authority received three inmates with bilateral leg swelling and difficulty in breathing from a detention camp for unauthorized immigrants. A case control study was conducted. Fasting blood samples of case and control groups were collected according to instructions of the laboratory for determining thiamine level, and their 1 week dietary intake was analyzed. 9% (21/226) of inmates had bilateral leg swelling, and 75% (6/8) of them had low thiamine level (
  18. Zamanian M, Qader Hamadneh LA, Veerakumarasivam A, Abdul Rahman S, Shohaimi S, Rosli R
    Cancer Cell Int, 2016;16:56.
    PMID: 27418879 DOI: 10.1186/s12935-016-0329-y
    The introduction of effective novel biomarkers of invasion and metastasis is integral for the advancement of breast cancer management. The present study focused on the identification and evaluation of calreticulin (CRT) as a potential biomarker for breast cancer invasion.
  19. Abdul Rahman S, Ahmad NI, Mohd Salim RJ, Muhamad NJ, Omar Hamdan AS, Leong YH
    Int J Anal Chem, 2024;2024:8581029.
    PMID: 38312506 DOI: 10.1155/2024/8581029
    It has been well-established that mycotoxins are poisonous chemical metabolites secreted by certain molds. Some of them significantly affect the health of humans and livestock. Increasing attention is now being paid to uncovering and identifying mycotoxins' presence in the building's environment. However, the main challenge remains in suitable and reliable analytical methods for their identification and detection in infected structures. GC-MS and LC-MS/MS techniques have been used extensively for mycotoxin analysis, and advancement in these techniques enabled a more comprehensive range of mycotoxins to be detected. As such, this study aimed to address a brief overview of various phenomena of existing sample collection, preparation, and analysis to detect mycotoxins in the building's environment. This scoping review includes articles from 2010 to 2020 available from PubMed, Scopus, Cochrane, Wiley, Google Scholar, and ScienceDirect. Duplicate articles were removed, and exclusion criteria were applied to eliminate unrelated studies, resulting in 14 eligible articles. The present study provides an overview of mycotoxin analysis by GC-MS and LC-MS/MS in buildings. Many techniques are available for analyzing and detecting multiple mycotoxins using these methods. Future efforts would focus on rapid assays and tools enabling measuring a broader range of mycotoxins in a single matrix and lower detection limits. In addition, it would assist future findings on new techniques and mycotoxins that existed in the building's environment.
  20. Mohammad Haniff MA, Muhammad Hafiz S, Wahid KA, Endut Z, Wah Lee H, Bien DC, et al.
    Sci Rep, 2015;5:14751.
    PMID: 26423893 DOI: 10.1038/srep14751
    In this work, the piezoresistive effects of defective graphene used on a flexible pressure sensor are demonstrated. The graphene used was deposited at substrate temperatures of 750, 850 and 1000 °C using the hot-filament thermal chemical vapor deposition method in which the resultant graphene had different defect densities. Incorporation of the graphene as the sensing materials in sensor device showed that a linear variation in the resistance change with the applied gas pressure was obtained in the range of 0 to 50 kPa. The deposition temperature of the graphene deposited on copper foil using this technique was shown to be capable of tuning the sensitivity of the flexible graphene-based pressure sensor. We found that the sensor performance is strongly dominated by the defect density in the graphene, where graphene with the highest defect density deposited at 750 °C exhibited an almost four-fold sensitivity as compared to that deposited at 1000 °C. This effect is believed to have been contributed by the scattering of charge carriers in the graphene networks through various forms such as from the defects in the graphene lattice itself, tunneling between graphene islands, and tunneling between defect-like structures.
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