Displaying publications 21 - 40 of 2007 in total

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  1. The role of digital transformation in supply chain efficiency and economic output
    Zhu H
    Environ Sci Pollut Res Int, 2024 Jan;31(3):3656-3668.
    PMID: 38091214 DOI: 10.1007/s11356-023-30984-w
    From the perspective of sustainable supply chain management (SSCM), this research looks at the key elements influencing how small- and medium-sized companies (SMEs) move toward a circular economy (CE). This research aims to understand the elements that influence SMEs to embrace CE principles and determine the real-world applications of SSCM practices. This research gathered and analyzed data from diverse European SMEs working inside CE networks using a mixed-method approach. We received answers from several of these firms using a survey form sent and emailed to them. The replies were then assessed using an independent t test to account for any biases. We used confirmatory factor analysis (CFA) for the validity assessment, compound consistency, and corrected-item-total association measures to validate the model's validity and reliability. According to our research, SMEs are influenced significantly by societal pressures, green economic incentives, and environmental dedication when deciding whether to adopt CE practices. Our study further emphasizes the importance of SSCM for SMEs' successful transition to a CE model, especially regarding resource and waste management efficiency. This work contributes to the corpus of research on the topic by providing empirical support for the function of SSCM in easing the transition towards CE in the setting of SMEs. The results might serve as a reference for managers and policymakers as they create plans to encourage SMEs to embrace CE practices and to emphasize the advantages of such a change on the economic, social, and environmental fronts. Putting a particular emphasis on the vital roles that public pressure, green financial incentives, and ecological dedication play, this research provides insights into the complex interactions between SSCM and CE transition in SMEs. Further study is needed to examine how these determinants could fluctuate across various industries and geographies.
    Matched MeSH terms: Reproducibility of Results
  2. Zeolite-iron oxide nanocomposite from fly ash formed a 'clubbell' structure: integration of cardiac biocapture macromolecules in serum on microelectrodes
    Liu Z, Gopinath SCB, Wang Z, Li Y, Anbu P, Zhang W
    Mikrochim Acta, 2021 05 15;188(6):187.
    PMID: 33990848 DOI: 10.1007/s00604-021-04834-w
    A new zeolite-iron oxide nanocomposite (ZEO-IO) was extracted from waste fly ash of a thermal power plant and utilized for capturing aptamers used to quantify the myocardial infarction (MI) biomarker N-terminal prohormone B-type natriuretic peptide (NT-ProBNP); this was used in a probe with an integrated microelectrode sensor. High-resolution microscopy revealed that ZEO-IO displayed a clubbell structure and a particle size range of 100-200 nm. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed the presence of Si, Al, Fe, and O in the synthesized ZEO-IO. The limit of detection for NT-ProBNP was 1-2 pg/mL (0.1-0.2 pM) when the aptamer was sandwiched with antibody and showed the doubled current response even at a low NT-ProBNP abundance. A dose-dependent interaction was identified for this sandwich with a linear plot in the concentration range 1 to 32 pg/mL (0.1-3.2 pM) with a determination coefficient R2 = 0.9884; y = 0.8425x-0.5771. Without  sandwich, the detection limit was 2-4 pg/mL (0.2-0.4 pM) and the determination coefficient was R2 = 0.9854; y = 1.0996x-1.4729. Stability and nonfouling assays in the presence of bovine serum albumin, cardiac troponin I, and myoglobin revealed that the aptamer-modified surface is stable and specific for NT-Pro-BNP. Moreover, NT-ProBNP-spiked human serum exhibited selective detection. This new nanocomposite-modified surface helps in detecting NT-Pro-BNP and diagnosing MI at stages of low expression.
    Matched MeSH terms: Reproducibility of Results
  3. Assessment of groundwater vulnerability to anthropogenic pollution and seawater intrusion in a small tropical island using index-based methods
    Kura NU, Ramli MF, Ibrahim S, Sulaiman WN, Aris AZ, Tanko AI, et al.
    Environ Sci Pollut Res Int, 2015 Jan;22(2):1512-33.
    PMID: 25163562 DOI: 10.1007/s11356-014-3444-0
    In this work, the DRASTIC and GALDIT models were employed to determine the groundwater vulnerability to contamination from anthropogenic activities and seawater intrusion in Kapas Island. In addition, the work also utilized sensitivity analysis to evaluate the influence of each individual parameter used in developing the final models. Based on these effects and variation indices of the said parameters, new effective weights were determined and were used to create modified DRASTIC and GALDIT models. The final DRASTIC model classified the island into five vulnerability classes: no risk (110-140), low (140-160), moderate (160-180), high (180-200), and very high (>200), covering 4, 26, 59, 4, and 7 % of the island, respectively. Likewise, for seawater intrusion, the modified GALDIT model delineates the island into four vulnerability classes: very low (<90), low (90-110), moderate (110-130), and high (>130) covering 39, 33, 18, and 9 % of the island, respectively. Both models show that the areas that are likely to be affected by anthropogenic pollution and seawater intrusion are within the alluvial deposit at the western part of the island. Pearson correlation was used to verify the reliability of the two models in predicting their respective contaminants. The correlation matrix showed a good relationship between DRASTIC model and nitrate (r = 0.58). In a similar development, the correlation also reveals a very strong negative relationship between GALDIT model and seawater contaminant indicator (resistivity Ωm) values (r = -0.86) suggesting that the model predicts more than 86 % of seawater intrusion. In order to facilitate management strategy, suitable areas for artificial recharge were identified through modeling. The result suggested some areas within the alluvial deposit at the western part of the island as suitable for artificial recharge. This work can serve as a guide for a full vulnerability assessment to anthropogenic pollution and seawater intrusion in small islands and will help policy maker and manager with understanding needed to ensure sustainability of the island's aquifer.
    Matched MeSH terms: Reproducibility of Results
  4. Validity and reliability of the Malay version of WHOQOL-HIV BREF in patients with HIV infection
    Saddki N, Noor MM, Norbanee TH, Rusli MA, Norzila Z, Zaharah S, et al.
    AIDS Care, 2009 Oct;21(10):1271-8.
    PMID: 20024703 DOI: 10.1080/09540120902803216
    This study determines the validity and reliability of the Malay version of the World Health Organization Quality of Life (WHOQOL) assessment instrument in patients with human immunodeficiency virus (HIV) infection. A cross-sectional study on 157 patients with HIV seen at the Infectious Disease Unit, Hospital Raja Perempuan Zainab II, Kota Bharu, Kelantan was conducted. Factor analysis identified five major domains: physical needs, spirituality, social relationship, psychological, and environment. Significant correlation was found between each domain scores and the general health questions. The instrument was able to discriminate between asymptomatic and symptomatic HIV positive patients for all domain scores except for the spirituality domain. The internal consistency of the five domains ranged from 0.70 to 0.83. The intraclass correlation coefficient (ICC) ranged from 0.60 to 0.87 across all domains. In conclusion, the Malay version of WHOQOL-HIV BREF is a valid and reliable instrument in assessing quality of life in HIV positive patients.
    Matched MeSH terms: Reproducibility of Results
  5. Fulltext Stochastic process and tutorial of the African buffalo optimization
    Odili JB, Noraziah A, Alkazemi B, Zarina M
    Sci Rep, 2022 Oct 15;12(1):17319.
    PMID: 36243886 DOI: 10.1038/s41598-022-22242-9
    This paper presents the data description of the African buffalo optimization algorithm (ABO). ABO is a recently-designed optimization algorithm that is inspired by the migrant behaviour of African buffalos in the vast African landscape. Organizing their large herds that could be over a thousand buffalos using just two principal sounds, the /maaa/ and the /waaa/ calls present a good foundation for the development of an optimization algorithm. Since elaborate descriptions of the manual workings of optimization algorithms are rare in literature, this paper aims at solving this problem, hence it is our main contribution. It is our belief that elaborate manual description of the workings of optimization algorithms make it user-friendly and encourage reproducibility of the experimental procedures performed using this algorithm. Again, our ability to describe the algorithm's basic flow, stochastic and data generation processes in a language so simple that any non-expert can appreciate and use as well as the practical implementation of the popular benchmark Rosenbrock and Shekel Foxhole functions with the novel algorithm will assist the research community in benefiting maximally from the contributions of this novel algorithm. Finally, benchmarking the good experimental output of the ABO with those of the popular, highly effective and efficient Cuckoo Search and Flower Pollination Algorithm underscores the ABO as a worthy contribution to the existing body of population-based optimization algorithms.
    Matched MeSH terms: Reproducibility of Results
  6. Mapping the world's free-flowing rivers
    Grill G, Lehner B, Thieme M, Geenen B, Tickner D, Antonelli F, et al.
    Nature, 2019 05;569(7755):215-221.
    PMID: 31068722 DOI: 10.1038/s41586-019-1111-9
    Free-flowing rivers (FFRs) support diverse, complex and dynamic ecosystems globally, providing important societal and economic services. Infrastructure development threatens the ecosystem processes, biodiversity and services that these rivers support. Here we assess the connectivity status of 12 million kilometres of rivers globally and identify those that remain free-flowing in their entire length. Only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length and 23 per cent flow uninterrupted to the ocean. Very long FFRs are largely restricted to remote regions of the Arctic and of the Amazon and Congo basins. In densely populated areas only few very long rivers remain free-flowing, such as the Irrawaddy and Salween. Dams and reservoirs and their up- and downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity. By applying a new method to quantify riverine connectivity and map FFRs, we provide a foundation for concerted global and national strategies to maintain or restore them.
    Matched MeSH terms: Reproducibility of Results
  7. Numerical algorithm of block method for general second order ODES using variable step size
    Nazreen Waeleh, Zanariah Abdul Majid
    Sains Malaysiana, 2017;46:817-824.
    This paper outlines an alternative algorithm for solving general second order ordinary differential equations (ODEs). Normally, the numerical method was designed for solving higher order ODEs by converting it into an n-dimensional first order equations with implementation of constant step length. Nevertheless, this involved a lot of computational complexity which led to consumption a lot of time. Consequently, a direct block multistep method with utilization of variable step size strategy is proposed. This method was developed for computing the solution at four points simultaneously and the derivation based on numerical integration as well as using interpolation approach. The convergence of the proposed method is justified under suitable conditions of stability and consistency. Five numerical examples are considered and some comparisons are made with the existing methods for demonstrating the validity and reliability of the proposed algorithm.
    Matched MeSH terms: Reproducibility of Results
  8. Fulltext Employer roles and responsibilities in occupational safety and health (OSH) implementation in Malaysia
    Mohd Esa Baruji, Sudin, Sham Xahary, Siti Zainatul Arafah, Nuraida Waslee, Siti Nasyrah Ibrahim, Nur Hidayana Abdullah, et al.
    Journal of Occupational Safety and Health, 2018;15(1):49-55.
    MyJurnal
    communication, full compliance and good behavior) as among the crucial elements required to be possessed by the principal employers in three sectors, namely manufacturing, public services and construction. In relation to this, this paper will describe the development and validation of instruments prior to the measurement of principal employers’ roles and responsibilities in the implementation of OSH. Three assessment tools were developed, namely the Benchmarking Interview, Questionnaire and Workplace Inspection. Fifteen companies were selected for the benchmarking interview, 50 employers conveniently selected for the survey interview (covering three sectors) and 90 employers selected for the workplace inspection (30 respondents for each sector). The development of benchmarking interview and workplace inspection scores are briefly discussed while the main focus is on the validation of the survey constructs (or items). The reliability check on 53 items representing four elements (i.e., Commitment, Communication, Compliance, Behaviour) of employers’ roles and responsibilities in the implementation of OSH showed that the Cronbach’s Alpha coefficient is more than 0.90 which indicates that the internal consistency is extremely reliable. It also indicates that the set of items in each element are closely related and well understood by the respondents. Validity check on the items based on the Rasch measurement infit and outfit mean square statistics and standardized z-score found that nine items had misfitting values and finally corrected for further analysis. This study had shown that a valid and reliable instruments are important in ensuring that accurate and precise findings are obtained in measuring the roles and responsibilities of principal employer in the implementation of OSH.
    Matched MeSH terms: Reproducibility of Results
  9. Fulltext Psychometric properties of the QOLLTI-F questionnaire to assess quality of life in caregivers of cancer patients
    Rafi Mahmoud Alnjadat, Aasim Adnan, Zalina Ismail
    Education in Medicine Journal, 2014;6(2):41-47.
    MyJurnal
    Aim: The objective of the present study was to assess the validity and reliability of Malay version of the QOLLTI-F questionnaire.
    Methods: A total of 80 Malay caregivers of cancer patients in an outpatient oncology clinic were enrolled in this study. A translated QOLLTI-F questionnaire of 16 items was used in order to assess their quality of life. Demographic characteristics were recorded. Both face and content validity of the translated version were carried out by professionals and the construct validity of the questionnaire was assessed by exploratory factor analysis.
    Results: Exploratory factor analysis led to the extraction of seven factors and this was consistent with the English version. Cronbach Alpha coefficient showed good consistency of the questions within the sub-scales (Cronbach's alpha > 0.7).
    Conclusion: This study was confined to a Malay population, and the analyses were potentially limited by a small sample size .Nevertheless, the translated questionnaire demonstrated valid and reliable psychometric properties when administered to Malay caregivers. Future studies are needed to see if this instrument can fit other samples in different settings and populations.
    Study site: Oncology clinic, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
    Matched MeSH terms: Reproducibility of Results
  10. Fulltext Validity and reliability of the Multidimensional Body Image Scale in Malaysian university students
    Gan WY, Mohd NM, Siti AH, Zalilah MS
    Malays J Nutr, 2012 Dec;18(3):295-306.
    PMID: 24568070 MyJurnal
    This study aimed to evaluate the validity and reliability of the Multidimensional Body Image Scale (MBIS), a seven-factor, 62-item scale developed for Malaysian female adolescents. This scale was evaluated among male and female Malaysian university students.
    Matched MeSH terms: Reproducibility of Results
  11. Fulltext Objective triceps muscle strength measurement using computerized adaptation
    Amalourde A, Vinayaga P, Naveed N, Choon SK, Zaleha O
    Med J Malaysia, 2004 Dec;59 Suppl F:8-13.
    PMID: 15941154
    In our centre the non-availability computerized exercise machines limits the objective monitoring of strength rehabilitation. We undertook this research programme to objectively measure triceps muscle strength by interfacing NORSK-Gym machine with accelerometer and positional transducers to a computer. This data was tabulated and processed using Microsoft Excel. The positional transducer was first calibrated and it showed an excellent Pearson Correlation Coefficients against a standard metric reading (r = 0.9999). Peak Force was used as a test parameter for isotonic triceps muscle strength measurements. The criterion-referenced validity was established as the peak forces measured using the accelerometer and positional transducer demonstrated identical Peak Forces (r = 0.94). Analysis of our mean Peak Force measurements using non-biological force as well as the intra-individual reproducibility demonstrated excellent Pearson Correlation Coefficients (r) = 0.982-0.998 and 0.929-0.972 respectively. This computerized adaptation of the NORSK-Gym machine produced an objective, valid and reproducible triceps muscle strength measurement.
    Matched MeSH terms: Reproducibility of Results
  12. External quality assurance in Malaysia
    Nawawi H, Lim HH, Zakiah I
    Southeast Asian J. Trop. Med. Public Health, 1999;30 Suppl 3:39-45.
    PMID: 10926257
    An activity supportive of the MOH QA Programme, the National EQAS for clinical chemistry monitors for analytical performance in core routine biochemical testing by the pathology laboratories, with unsatisfactory performance scores serving to alert against deficiencies or problems and the scores in subsequent challenges providing the feedback of effectiveness of remedial actions taken. While unacceptable individual analyte performance score (variance index score, VIS) indicated problems in instruments, reagent and calibrators, or the use of inherently poorer methods, repeated occurrence of unsatisfactory OMRVIS was traceable to generally poor laboratory management of usually inadequately-equipment small laboratories. The outcome has been one of slow but gradual improvement in the overall performance of participating laboratories, with a move towards methods upgrading and standardization to achieve greater concordance of results. Presently, the programme is limited to 61 government and 4 private hospital laboratories in the country for 12 commonly assayed clinical biochemistry analytes. It is hoped that the NEQAS could be extended to the other private laboratories and that of academic institutions. However, this is dependent to a large extent on the manpower and financial support obtainable by the organizing body of the programme in the future. Belk and Sunderman, 1947 demonstrated that laboratories participating in an quality assessment scheme could rapidly and dramatically improve their analytical performance. In some countries, participation has become mandatory, and acceptable performance is a requirement in laboratory accreditation. The need and value of the NEQAP is, therefore, evident. While there may be limitations in the national programme. efforts are being made at improving the programme within the means and resources of the organising body. The goals of the NEQAP are not just to monitor performance but also to educate. On this, matters related to and supportive of these goals have also been pursued. The annual workshop/forum on quality controls had allowed exchange of information between representatives of participating laboratories and the organising body. Recently in the 1997 MOH Quality Improvement evaluation, Quality Control has been evaluated together with the other 17 such activities. The study on knowledge, attitude and practice has provided the necessary feedback and will be used for future planning in making efforts at increasing the effectiveness and benefits of the all QC activities including this NEQAP for clinical chemistry. In addition, there is a need to look into areas such as selection of methods and test systems, and improvement of continuing education, training as well as research in quality improvement as suggested by the Quality Improvement evaluation.
    Matched MeSH terms: Reproducibility of Results
  13. Fulltext An Industrial IoT-Based Blockchain-Enabled Secure Searchable Encryption Approach for Healthcare Systems Using Neural Network
    Ali A, Almaiah MA, Hajjej F, Pasha MF, Fang OH, Khan R, et al.
    Sensors (Basel), 2022 Jan 12;22(2).
    PMID: 35062530 DOI: 10.3390/s22020572
    The IoT refers to the interconnection of things to the physical network that is embedded with software, sensors, and other devices to exchange information from one device to the other. The interconnection of devices means there is the possibility of challenges such as security, trustworthiness, reliability, confidentiality, and so on. To address these issues, we have proposed a novel group theory (GT)-based binary spring search (BSS) algorithm which consists of a hybrid deep neural network approach. The proposed approach effectively detects the intrusion within the IoT network. Initially, the privacy-preserving technology was implemented using a blockchain-based methodology. Security of patient health records (PHR) is the most critical aspect of cryptography over the Internet due to its value and importance, preferably in the Internet of Medical Things (IoMT). Search keywords access mechanism is one of the typical approaches used to access PHR from a database, but it is susceptible to various security vulnerabilities. Although blockchain-enabled healthcare systems provide security, it may lead to some loopholes in the existing state of the art. In literature, blockchain-enabled frameworks have been presented to resolve those issues. However, these methods have primarily focused on data storage and blockchain is used as a database. In this paper, blockchain as a distributed database is proposed with a homomorphic encryption technique to ensure a secure search and keywords-based access to the database. Additionally, the proposed approach provides a secure key revocation mechanism and updates various policies accordingly. As a result, a secure patient healthcare data access scheme is devised, which integrates blockchain and trust chain to fulfill the efficiency and security issues in the current schemes for sharing both types of digital healthcare data. Hence, our proposed approach provides more security, efficiency, and transparency with cost-effectiveness. We performed our simulations based on the blockchain-based tool Hyperledger Fabric and OrigionLab for analysis and evaluation. We compared our proposed results with the benchmark models, respectively. Our comparative analysis justifies that our proposed framework provides better security and searchable mechanism for the healthcare system.
    Matched MeSH terms: Reproducibility of Results
  14. Fulltext Validity and Reliability Aspects of a Newly Developed Questionnaire for Auditory Localization
    Zakaria MN
    J Int Adv Otol, 2019 Apr;15(1):182-183.
    PMID: 30924773 DOI: 10.5152/iao.2019.5959
    Matched MeSH terms: Reproducibility of Results
  15. Prospective diagnostic study on the use of narrow-band imaging on suspicious lesions during colonoscopy examination
    Yaacob H, Ikhwan SM, Hashim MN, Syed Abd Aziz SH, Wan Zain WZ, Tuan Sharif SE, et al.
    Asian J Endosc Surg, 2018 Nov;11(4):318-324.
    PMID: 29424061 DOI: 10.1111/ases.12463
    INTRODUCTION: Colonoscopy is the gold standard to detect colorectal neoplasm. Narrow-band imaging (NBI) has a good diagnostic accuracy to differentiate between neoplastic and non-neoplastic colorectal lesions. This study explores the diagnostic validity of NBI colonoscopy as well as its associated factors related to neoplastic and non-neoplastic colorectal lesions.

    METHODS: This study enrolled 100 patients in a single-center tertiary teaching hospital. Patients presented for screening colonoscopy, and those with suspicious colorectal lesions were included in this study. During colonoscopy, the most suspicious lesion in each patient was analyzed using the NBI system based on Sano's classification. Each lesion was biopsied for histopathological analysis, the gold standard. Endoscopic images were captured electronically. The sensitivity, specificity, and diagnostic accuracy of NBI colonoscopy were assessed. Other associated factors related to neoplastic and non-neoplastic lesions were analyzed accordingly.

    RESULTS: The sensitivity and specificity of the NBI were 88.2% and 71.9%, respectively. The area under the receiver-operator curve was 0.801, indicating that NBI has a good ability to differentiate between disease and non-disease. There are significant associations between histopathological examination outcomes and both presenting symptoms, especially weight loss, and lesion site, even after other variables were controlled (P 

    Matched MeSH terms: Reproducibility of Results
  16. Fulltext Optimization of an Ultrasound-Assisted Extraction Condition for Flavonoid Compounds from Cocoa Shells (Theobroma cacao) Using Response Surface Methodology
    Md Yusof AH, Abd Gani SS, Zaidan UH, Halmi MIE, Zainudin BH
    Molecules, 2019 Feb 16;24(4).
    PMID: 30781448 DOI: 10.3390/molecules24040711
    This study investigates the ultrasound-assisted extraction of flavonoids from Malaysian cocoa shell extracts, and optimization using response surface methodology. There are three variables involved in this study, namely: ethanol concentration (70⁻90 v/v %), temperature (45⁻65 °C), and ultrasound irradiation time (30⁻60 min). All of the data were collected and analyzed for variance (ANOVA). The coefficient of determination (R²) and the model was significant in interaction between all variables (98% and p < 0.0001, respectively). In addition, the lack of fit test for the model was not of significance, with p > 0.0684. The ethanol concentration, temperature, and ultrasound irradiation time that yielded the maximum value of the total flavonoid content (TFC; 7.47 mg RE/g dried weight (DW)) was 80%, 55 °C, and 45 min, respectively. The optimum value from the validation of the experimental TFC was 7.23 ± 0.15 mg of rutin, equivalent per gram of extract with ethanol concentration, temperature, and ultrasound irradiation time values of 74.20%, 49.99 °C, and 42.82 min, respectively. While the modelled equation fits the data, the T-test is not significant, suggesting that the experimental values agree with those predicted by the response surface methodology models.
    Matched MeSH terms: Reproducibility of Results
  17. Fulltext Translation, validation and psychometric properties of Bahasa Malaysia version of the Depression Anxiety and Stress Scales (DASS)
    Ramli Musa, Mohd Ariff Fadzil, Zaini Zain
    ASEAN Journal of Psychiatry, 2007;8(2):82-89.
    MyJurnal
    Background: Up to date, there are handful questionnaires that have been validated in Bahasa Malaysia (BM). This study aimed to translate the Depression Anxiety Stress Scales 21-item (DASS-21) and measure its psychometric properties. Objectives: To determine the construct validity and acceptability of the DASS, BM. Methods: Two forward and backward translations were done in BM in accordance to guideline, and its validation was determined by using confirmatory factor analysis. A total of 263 subjects were selected by systematic random sampling to represent Malaysian population for reliability and validity purposes. Results: The BM DASS-21 had very good Cronbach’s alpha values of .84, .74 and .79, respectively, for depression, anxiety and stress. In addition, it had good factor loading values for most items (.39 to .73). Correlations among scales were between .54 and .68. Conclusions: BM DASS-21 is correctly and adequately translated to Bahasa Malaysia with high psychometric properties. Further studies are required to support these findings.
    Matched MeSH terms: Reproducibility of Results
  18. Fulltext Lightning performance analysis of a rooftop grid-connected solar photovoltaic without external lightning protection system
    Nasir MSM, Ab-Kadir MZA, Radzi MAM, Izadi M, Ahmad NI, Zaini NH
    PLoS One, 2019;14(7):e0219326.
    PMID: 31295278 DOI: 10.1371/journal.pone.0219326
    The Sustainable Energy Development Authority of Malaysia (SEDA) regularly receives complaints about damaged components and distribution boards of PV systems due to lightning strikes. Permanent and momentary interruptions of distribution circuits may also occur from the disturbance. In this paper, a solar PV Rooftop system (3.91 kWp) provided by SEDA was modelled in the PSCAD/EMTDC. The Heidler function was used as a lightning current waveform model to analyse the transient current and voltage at two different points susceptible to the influence of lightning events such as different lightning current wave shape, standard lightning current and non-standard lightning current. This study examines the effect on the system components when lightning directly strikes at two different points of the installation. The two points lie between the inverter and the solar PV array and between inverter and grid. Exceptionally high current and voltage due to the direct lightning strike on a certain point of a PV Rooftop system was also studied. The result of this case study is observed with and without the inclusion of surge protective devices (SPDs). The parameters used were 31 kA of peak current, 10 metres cable length and lightning impulse current wave shape of 8/20μs. The high current and voltage at P1 striking point were 31 kA and 2397 kV, respectively. As for the AC part, the current and voltage values were found to be 5.97 kA and 5392 kV, respectively.Therefore, SPDs with suitable rating provided by SEDA were deployed. Results showed that high transient current voltage is expected to clamp sharply at the values of 1.915 kV and 0 A at the P1 striking point. As for the AC part, the current and voltage values were found to be 0 kA and 0.751 V, respectively. Varying lightning impulse current wave shapes at striking point P2 showed that the highest voltage was obtained at waveshape 10/350 μs at 11277 kV followed by wave shapes of 2/70 μs, 8/20 μs and 0.7/6 μs. The high value of transient voltage was clamped at a lower level of 2.029 kV. Different lightning amplitudes were also applied, ranging from 2-200 kA selected based on the CIGRE distribution. It showed that the current and voltage at P1 and P2 were directly proportional. Therefore, the SPD will be designed at an acceptable rating and proper position of SPD installation at solar PV Rooftop will be proposed. The results obtained in this study can then be utilised to appropriately assign a SPD to protect the PV systems that are connected to the grid. Installing SPDs without considering the needs of lightning protection zones would expose the expensive equipment to potential damage even though the proper energy coordination of SPDs is in place. As such, the simulation results provide a basis for controlling the impacts of direct lightning strikes on electrical equipment and power grids and thus justify SPD coordination to ensure the reliability of the system.
    Matched MeSH terms: Reproducibility of Results
  19. Fulltext The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes
    Mohamed J, Shing SW, Idris MH, Budin SB, Zainalabidin S
    Clinics (Sao Paulo), 2013 Oct;68(10):1358-63.
    PMID: 24212844 DOI: 10.6061/clinics/2013(10)11
    OBJECTIVES: The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes.

    METHODS: Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days.

    RESULTS: The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained.

    CONCLUSION: The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients.

    Matched MeSH terms: Reproducibility of Results
  20. Fulltext Factorial validation of the Malay version of multidimensional scale of perceived social support among a group of psychiatric patients
    Ng, C.G., Nurasikin, M.S., Loh, H.S., Yee, Anne H.A., Zainal, N.Z.
    Malaysian Journal of Psychiatry, 2012;21(2):0-0.
    MyJurnal
    Introduction: There is increasing awareness of the contribution of perceived social support (PSS) to emotional and physical well-being. Numerous scales measuring PSS have been developed, including the widely used Multidimensional Scale of Perceived Social Support (MSPSS). The psychometric properties of the MSPSS have been demonstrated in diverse samples, however mostly are conducted in English. Malay is the official languange in Malaysia, and this study was conducted to provide evidence of the validity and reliability of a Malay version MSPSS (MSPSS-M) suited for our population.
    Methods: This is a cross sectional study. The socio-demographic and clinical information of the selected patients from psychiatric outpatient clinic over a 3-month period, were obtained via pre-designed questionnaire, interviews and medical records. Assessment of psychiatric symptoms and social support were measured by various instruments including the Brief Psychiatric Rating Scale (BPRS-E), Depressive, Anxiety and Stress Scale (DASS) and MSPSS-M.
    Results: Data were reported for 228 psychiatric outpatients with the mean age of 40.3 years old. The 3-factor structure of the MSPSS-M (significant others, family, and friends) fitted the data well. The MSPSS-M showed good internal consistency (Cronbach α of 0.89) and validity. The scores of the total subscales for MSPSS-M were negatively correlated with the depression subscale in DASS (P < 0.05). BPRS was negatively correlated with significant others (P < 0.01) compared to the other two subscales in MSPSS-M.
    Conclusions: The Malay version MSPSS (MSPSS-M) is a psychometrically valid instrument with high internal consistency, which is useful in assessing perceived social support in Malaysian population.

    Study site: psychiatric clinic, University Malaya
    Medical Center (UMMC)
    Matched MeSH terms: Reproducibility of Results
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