MyMedR

Displaying publications 41 - 60 of 110 in total

Abstract:

Sort:

Fulltext Modeling of high voltage induction motor cooling system using linear regression mathematical models

Rosli NS, Ibrahim R, Ismail I, Omar M

PLoS One, 2022;17(11):e0276142.
PMID: 36445921 DOI: 10.1371/journal.pone.0276142

Achieving reliable power efficiency from a high voltage induction motor (HVIM) is a great challenge, as the rigorous control strategy is susceptible to unexpected failure. External cooling is commonly used in an HVIM cooling system, and it is a vital part of the motor that is responsible for keeping the motor at the proper operating temperature. A malfunctioning cooling system component can cause motor overheating, which can destroy the motor and cause the entire plant to shut down. As a result, creating a dynamic model of the motor cooling system for quality performance, failure diagnosis, and prediction is critical. However, the external motor cooling system design in HVIM is limited and separately done in the past. With this issue in mind, this paper proposes a combined modeling approach to the HVIM cooling system which consists of integrating the electrical, thermal, and cooler model using the mathematical model for thermal performance improvement. Firstly, the development of an electrical model using an established mathematical model. Subsequently, the development of a thermal model using combined mathematical and linear regression models to produce motor temperature. Then, a modified cooler model is developed to provide cold air temperature for cooling monitoring. All validated models are integrated into a single model called the HVIM cooling system as the actual setup of the HVIM. Ultimately, the core of this modeling approach is integrating all models to accurately represent the actual signals of the motor cooler temperature. Then, the actual signals are used to validate the whole structure of the model using Mean Absolute Percentage Error (MAPE) and Root Mean Square Error (RMSE) analysis. The results demonstrate the high accuracy of the HVIM cooling system representation with less than 1% error tolerance based on the industrial plant experts. Thus, it will be helpful for future utilization in quality maintenance, fault identification and prediction study.
Fulltext The association between depression and sexual satisfaction among Malay elderly in Malaysia

Mat Din H, Nor Akahbar SA, Ibrahim R

Heliyon, 2019 Jun;5(6):e01940.
PMID: 31338454 DOI: 10.1016/j.heliyon.2019.e01940

BACKGROUND: Malaysia is experiencing population ageing and expects to be an aged nation by 2030. Depression is one of the common disorder among elderly worldwide and the prevalence of depression in Malaysia is expected to increase as a result of population ageing. The association of depression and sexual satisfaction was unclear, particularly among the elderly. Therefore, this study aimed to examine the association between depression and sexual satisfaction among the Malay elderly population.
METHODS: One hundred and nine married community-dwelling elderly (Mean age = 63.23 years old) participated in this cross-sectional study. Hierarchical logistics regression was used to examine the association of depression on sexual satisfaction while controlling for potential confounders.
RESULTS: Prevalence of depression and sexual dissatisfaction were 26.6% and 20.2%, respectively. Depression was significantly associated with sexual satisfaction (P = 0.002; OR = 0.19, 95% CI = 0.06, 0.66). Depressed participants were 81% less likely to experience sexual satisfaction compared to those without depression.
LIMITATIONS: Cross-sectional study design assessing the association between depression and sexual satisfaction.
CONCLUSIONS: Findings from this study suggest that attention should be given to the prevention and treatment of depression among the elderly as a mechanism to improve sexual health.
Fulltext A Novel Hybrid Harris Hawk-Arithmetic Optimization Algorithm for Industrial Wireless Mesh Networks

Devan PAM, Ibrahim R, Omar M, Bingi K, Abdulrab H

Sensors (Basel), 2023 Jul 07;23(13).
PMID: 37448072 DOI: 10.3390/s23136224

A novel hybrid Harris Hawk-Arithmetic Optimization Algorithm (HHAOA) for optimizing the Industrial Wireless Mesh Networks (WMNs) and real-time pressure process control was proposed in this research article. The proposed algorithm uses inspiration from Harris Hawk Optimization and the Arithmetic Optimization Algorithm to improve position relocation problems, premature convergence, and the poor accuracy the existing techniques face. The HHAOA algorithm was evaluated on various benchmark functions and compared with other optimization algorithms, namely Arithmetic Optimization Algorithm, Moth Flame Optimization, Sine Cosine Algorithm, Grey Wolf Optimization, and Harris Hawk Optimization. The proposed algorithm was also applied to a real-world industrial wireless mesh network simulation and experimentation on the real-time pressure process control system. All the results demonstrate that the HHAOA algorithm outperforms different algorithms regarding mean, standard deviation, convergence speed, accuracy, and robustness and improves client router connectivity and network congestion with a 31.7% reduction in Wireless Mesh Network routers. In the real-time pressure process, the HHAOA optimized Fractional-order Predictive PI (FOPPI) Controller produced a robust and smoother control signal leading to minimal peak overshoot and an average of a 53.244% faster settling. Based on the results, the algorithm enhanced the efficiency and reliability of industrial wireless networks and real-time pressure process control systems, which are critical for industrial automation and control applications.
Fulltext Smoking and cognitive impairment among older persons in Malaysia

Momtaz YA, Ibrahim R, Hamid TA, Chai ST

Am J Alzheimers Dis Other Demen, 2015 Jun;30(4):405-11.
PMID: 25260596 DOI: 10.1177/1533317514552318

INTRODUCTION: Previous studies have shown conflicting results on the association between smoking and cognitive function. This study aims to examine the relationship of smoking with cognitive function.
METHODOLOGY: Data for the study, consisting of 2553 older adults aged 60 years and older, were drawn from a nationwide household survey entitled "Determinants of Wellness among Older Malaysians: A Health Promotion Perspective" conducted in 2010.
RESULTS: Current smokers had lower rates of cognitive impairment compared to never smokers (17.4% vs 25.9%), while cognitive function in former or ex-smokers was almost similar to that of the never smokers. Findings from multiple logistic regression analysis showed that current smokers were 37% less likely to be cognitively impaired, compared to the never smokers (odds ratio [OR] = .63; 95% confidence interval [CI]: .46-.86) while controlling for potential confounders. No difference in cognitive function was observed between former smokers and never smokers (OR = .94; 95% CI: .71-1.25).
CONCLUSION: Although the findings indicated a negative association between cigarette smoking and cognitive impairment, we are unable to conclude whether this relationship is causal or affected by other unmeasured confounding factors, especially survival bias.
Fulltext Developing and evaluating the effectiveness of mobile phone-based career intervention for career competencies of Malaysian public managers: Protocol for a mixed method study

Ho HH, Mohd Rasdi R, Ibrahim R, Md Khambari MN

Internet Interv, 2020 Dec;22:100349.
PMID: 32995304 DOI: 10.1016/j.invent.2020.100349

BACKGROUND: This study presents a protocol for a mixed method study on the development and evaluation of the effectiveness of mobile phone-based intervention for enhancing career competencies of managers in the Malaysian public service. Career competencies, being central to the self-management and development of one's career, are necessary for proactive management of careers; they help to guide the individuals towards subjective career success which subsequently leads to organization success. However, there is a lack of career competencies intervention practices in the Malaysian public service. Therefore, this study aims to develop and evaluate the effectiveness of a user and expert centric mobile phone-based career intervention program of career competencies among Malaysian public managers. In this study, the Social Cognitive Career Theory (SCCT) is adopted as the framework to develop mobile phone-based intervention for career competencies.
METHOD: This is a sequential exploratory mixed method study which involves, in Phase 1, a qualitative approach: reviewing of literature and interviewing experts and public servants who are users of mobile phones so as to obtain their perspectives regarding the components in the career intervention module and mobile phone application features. A quantitative approach is implemented in Phase 2 that evaluates the mobile phone-based career intervention program. Validation will be conducted to meet the objectives of (i) the usability of the mobile communication career intervention application (survey), and (ii) evaluation of the effectiveness of the intervention program for career competencies delivered through mobile phone application (randomized controlled trial). The career intervention program consists of five modules through which development is based on reflective, communicative and behavioral dimensions.
OUTCOME: The primary outcome of this study is career competencies. The career competencies score will be compared between participants in the intervention and control group at the baseline, and follow-ups at week four and week 12 respectively, using mixed design ANOVA.
DISCUSSION: The results from this study will indicate the effectiveness of the career intervention program for career competencies in the reformation of public services management. The intervention can serve as a new modality to enhance career competencies among public managers in Malaysia if its effectiveness is proven.
Fulltext Factors related with lung functions among Orang Asli in Tasik Chini, Malaysia: a cross-sectional study

Mohd Razib NF, Ismail H, Ibrahim R, Isa ZM

BMC Public Health, 2024 Jul 05;24(1):1791.
PMID: 38970028 DOI: 10.1186/s12889-024-19296-x

BACKGROUND: Orang Asli lifestyle and household setting may influence their health status especially respiratory system and lung functions. This cross-sectional study was carried out to investigate the status of lung functions of Orang Asli community and the associated factors.
METHODS: Data collection was carried out from November 2017 until May 2018 among 211 Orang Asli respondents aged 18 years old and above, who lived in five villages in Tasik Chini, Pahang. All respondents who fulfilled the inclusion criteria were recruited in this study. Interview-guided questionnaire was administered, and spirometry test that include Forced Expiratory Volume in one second (FEV1), Forced Vital Capacity (FVC), and Peak Expiratory Flow Rate (PEFR) was carried out. Data were analyzed using SPSS software version 23.0. In the first stage, descriptive analysis was done to describe the characteristics of the respondents. In the second stage, bivariable analysis was carried out to compare proportions. Finally, multiple logistic regression was performed to assess the effects of various independent predictors on spirometry parameters.
RESULTS: The respondents' age ranged from 18 to 71 years old in which 50.2% of them were female. The majority ethnicity in Tasik Chini was Jakun tribe (94.3%). More than half of the respondents (52.1%) were current smoker, 5.2% were ex-smoker and 41.7% were non-smoker. More than half of them (62.1%) used woodstove for cooking, compared to only 37.9% used cleaner fuel like Liquefied Petroleum Gas (LPG) as a fuel for everyday cooking activity. The lung function parameters (FEV1 and FVC) were lower than the predictive value, whereas the ratio of Forced Expiratory Volume in one second and Forced Vital Capacity (FEV1/FVC) (%) and PEFR were within the predictive value. The FEV1 levels were significantly associated with age group (18-39 years old) (p = 0.002) and presence of woodstove in the house (p = 0.004). FVC levels were significantly associated with presence of woodstove in the house (p = 0.004), whereas there were no significant associations between all factors and FEV1/FVC levels.
CONCLUSIONS: FEV1 levels were significantly associated with age group 18-39 years old, whereas FVC levels were significantly associated with the presence of woodstove in the house. Thus, environmental interventions such as replacing the use of woodstove with LPG, need to be carried out to prevent further worsening of respiratory health among Orang Asli who lived far from health facilities. Moreover, closer health monitoring is crucial especially among the younger and productive age group.
Fulltext A Case Report of Juvenile-Onset Recurrent Respiratory Papillomatosis

Kamaruzaman F, Ibrahim R, Nik Mohd NK, Mohd Shakri N

Cureus, 2024 Jun;16(6):e62734.
PMID: 39036277 DOI: 10.7759/cureus.62734

The most common benign laryngeal neoplasm in children is a papilloma. Laryngeal papillomatosis is a chronic disease and is rare in children. We report the case of a four-year-old Malay girl in whom chronic laryngeal papillomatosis, most likely acquired vertically during labor, was detected. She presented with hoarseness of voice for three years, and a flexible laryngoscopy examination revealed features of papilloma in the glottis area. The patient underwent direct laryngoscopy followed by excision of mass using the cold instrument. Surgical intervention is the primary treatment modality for laryngeal papillomatosis to maintain airway patency and voice quality.
Psychometric Properties of the Teleprimary Care Oral Health Clinical Information System (TPC-OHCIS) Questionnaire Using the Rasch Model

Ismail S, Sutan R, Ibrahim R, Mohd Rathi FZ

Cureus, 2024 Jun;16(6):e63064.
PMID: 39055416 DOI: 10.7759/cureus.63064

Background The Tele Primary Care Oral Health Clinical Information System (TPC-OHCIS) was implemented in Malaysia to digitalize health care and reduce numerous ground-level manual tasks. This study measures the psychometric properties of the TPC-OHCIS questionnaire among healthcare workers (HCWs) at primary healthcare clinics (PHC). Method A pilot study was conducted at PHC, which implemented the TPC-OHCIS application for service delivery. The questionnaire contained 65 items with four response categories, grouped into four scales: technology, organization, external support, and human resource. The questionnaire items were analyzed using the Rasch model in Winsteps 3.72.3. Results There were 319 respondents who participated (98.8%). The Cronbach alpha was 0.93. The construct validity was determined by a positive point measure correlation (PMC) value, with an infit and outfit mean square (MNSQ) range of 0.4-1.5 and a Z-standardized (ZSTD) range of -2.0 to 2.0. The person and item reliability were 0.93 and 0.97, respectively, indicating excellent reliability. The questionnaire was unidimensional, where the raw variance explained by measures was >40%. Conclusion The questionnaire was deemed fit for an actual survey after 18 items had been deleted. It has good psychometric properties and is practically applicable for evaluating HCWs on the TPC-OHCIS application implementation process monitoring using the local Malay language. High reliability and unidimensionality were achieved, supporting its use in digital healthcare. With this validated questionnaire, it will enhance digital healthcare implementation and streamline manual tasks.
Fulltext The role of illness perception in the physical activity domain of health-promoting lifestyle among patients with non-communicable diseases: A systematic review

Syed Shamsuddin SM, Ahmad N, Radi MFM, Ibrahim R

PLoS One, 2024;19(11):e0311427.
PMID: 39514466 DOI: 10.1371/journal.pone.0311427

BACKGROUND: The global mortality caused by non-communicable diseases is on the rise. Health-promoting lifestyles are among the most effective approaches, yet the physical activity domain consistently scores the lowest. Physical activity is linked to individual behaviour and influenced by numerous factors. Illness has been identified as a key factor in behavioural change. Therefore, the primary purpose of this review was to investigate the role of illness perception in the physical activity domain among patients with non-communicable disease.
METHOD: This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. A literature search was conducted across three scientific databases (Scopus, PubMed, and Web of Science), targeting original articles published in English between 2014 and 2024. The quality of the eligible articles was assessed using the Joanna Briggs Institute Critical Appraisal tools. The findings were synthesised through content analysis.
RESULTS: A total of 17 studies were included, identifying both the direct and indirect effects of illness perception variables as a whole or in their respective dimensions. The illness perception variable has demonstrated a significant positive and negative relationships with the physical activity domain.
LIMITATION: The majority of the included studies had a cross-sectional design. Therefore, the evidence quality was relatively low and exhibited a high risk of bias. Furthermore, there was language bias as only English-language publications were selected.
CONCLUSION: The findings of this review will serve as a guide for healthcare providers in enhancing physical activity adherence among patients with non-communicable diseases through an illness perception approach. This approach can be integrated into clinic consultations and intervention programmes. Future studies are warranted to evaluate the effectiveness of the illness perception approach in promoting physical activity adherence.
Fulltext A Review of Staphylococcal Cassette Chromosome mec (SCCmec) Types in Coagulase-Negative Staphylococci (CoNS) Species

Saber H, Jasni AS, Jamaluddin TZMT, Ibrahim R

Malays J Med Sci, 2017 Oct;24(5):7-18.
PMID: 29386968 MyJurnal DOI: 10.21315/mjms2017.24.5.2

Coagulase-negative staphylococci (CoNS) are considered low pathogenic organisms. However, they are progressively causing more serious infections with time because they have adapted well to various antibiotics owing to their ability to form biofilms. Few studies have been conducted on CoNS in both, hospital and community-acquired settings, especially in Malaysia. Thus, it is important to study their species and gene distributions. A mobile genetic element, staphylococcal cassette chromosome mec (SCCmec), plays an important role in staphylococci pathogenesis. Among CoNS, SCCmec has been studied less frequently than Staphylococcus aureus (coagulase-positive staphylococci). A recent study (8) conducted in Malaysia successfully detected SCCmec type I to VIII as well as several new combination patterns in CoNS species, particularly Staphylococcus epidermidis. However, data are still limited, and further research is warranted. This paper provides a review on SCCmec types among CoNS species.
Anthropometric indices and life style practices of the indigenous Orang Asli adults in Lembah Belum, Grik of Peninsular Malaysia

Yusof HM, Ching TS, Ibrahim R, Lola S

Asia Pac J Clin Nutr, 2007;16(1):49-55.
PMID: 17215180

A nutritional status survey of Orang Asli (Aboriginal) adults in Lembah Belum, Grik, has been conducted involving a total of 138 subjects. Jahai (58.7%) was the main ethnic group as compared to that of Temiar (41.3%). Based on the Body Mass Index (BMI) characteristics, the majority (63.2%) of the respondents were normal, 26.7% underweight and 10.1% were either overweight or obese. However, by using two different indices of waist circumference and waist-to-hip ratio, 1.6% and 10.8% of the total respondents revealed abdominal obesity, respectively. Measurement of mid upper arm muscle circumference (MUAMC) indicated that about 40% showed nutritional insufficiency whereas 0.8% showed over-nutrition. Body fat classification revealed that 53.4% of the respondents were thin, 45.8% at normal level and only 0.8% were obese. Student's t-test revealed a significant difference in anthropometric indices of body weight, height, MUAMC, triceps, sub-scapular, supra-iliac and body fat according to gender. Meanwhile, analysis of variance (ANOVA) showed significant differences in body weight, waist circumference, WHR and body fat according to different age categories. It was also found that those who smoked had lower BMI compared with non-smokers. Alcohol consumption was associated with higher BMI and WHR among the respondents. Pearson's correlation test between anthropometric measurements and socio-economic and demographic factors showed that ethnic group was the strongest variable.
Fulltext Does food insufficiency in childhood contribute to dementia in later life?

Momtaz YA, Haron SA, Hamid TA, Ibrahim R, Masud J

Clin Interv Aging, 2015;10:49-53.
PMID: 25565786 DOI: 10.2147/CIA.S69220

Despite several studies attempting to identify the risk factors for dementia, little is known about the impact of childhood living conditions on cognitive function in later life. The present study aims to examine the unique contribution of food insufficiency in childhood to dementia in old age.
Fulltext Dyadic effects of attitude toward aging on psychological well-being of older Malaysian couples: an actor-partner interdependence model

Momtaz YA, Hamid TA, Masud J, Haron SA, Ibrahim R

Clin Interv Aging, 2013;8:1413-20.
PMID: 24174873 DOI: 10.2147/CIA.S51877

BACKGROUND: There is a growing body of literature indicating that attitudes toward aging significantly affect older adults' psychological well-being. However, there is a paucity of scientific investigations examining the role of older adults' attitudes toward aging on their spouses' psychological well-being. Therefore, the present study aimed to examine the dyadic effects of attitude toward aging on the psychological well-being of older couples.
METHODS: Data for the present study, consisting of 300 couples aged 50 years and older, were drawn from a community-based survey entitled "Poverty among Elderly Women: Case Study of Amanah Ikhtiar" conducted in Peninsular Malaysia. An actor-partner interdependence model using AMOS version 20 (Europress Software, Cheshire, UK) was used to analyze the dyadic data.
RESULTS: The mean ages of the husbands and wives in this sample were 60.37 years (±6.55) and 56.33 years (±5.32), respectively. Interdependence analyses revealed significant association between older adults' attitudes toward aging and the attitudes of their spouses (intraclass correlation =0.59; P<0.001), and similar interdependence was found for psychological well-being (intraclass correlation =0.57; P<0.001). The findings from AMOS revealed that the proposed model fits the data (CMIN/degrees of freedom =3.23; goodness-of-fit index =0.90; confirmatory fit index =0.91; root mean square error of approximation =0.08). Results of the actor-partner independence model indicated that older adults' psychological well-being is significantly predicted by their spouses' attitudes toward aging, both among older men (critical ratio =2.92; P<0.01) and women (critical ratio =2.70; P<0.01). Husbands' and wives' own reports of their attitudes toward aging were significantly correlated with their own and their spouses' psychological well-being.
CONCLUSION: The findings from this study supported the proposed Spousal Attitude-Well-Being Model, where older adults' attitudes toward aging significantly affected their own and their spouses' psychological well-being. The theoretical and practical implications of the findings are discussed.
KEYWORDS: aged; attitude toward aging; psychological well-being
Fulltext Viability reduction and Rac1 gene downregulation of heterogeneous ex-vivo glioma acute slice infected by the oncolytic Newcastle disease virus strain V4UPM

Mustafa Z, Shamsuddin HS, Ideris A, Ibrahim R, Jaafar H, Ali AM, et al.

Biomed Res Int, 2013;2013:248507.
PMID: 23586025 DOI: 10.1155/2013/248507

Oncolytic viruses have been extensively evaluated for anticancer therapy because this virus preferentially infects cancer cells without interfering with normal cells. Newcastle Disease Virus (NDV) is an avian virus and one of the intensively studied oncolytic viruses affecting many types of cancer including glioma. Nevertheless, the capability of NDV infection on heterogeneous glioma tissue in a cerebrospinal fluid atmosphere has never been reported. Recently, Rac1 is reported to be required for efficient NDV replication in human cancer cells and established a link between tumourigenesis and sensitivity to NDV. Rac1 is a member of the Rho GTPases involved in the regulation of the cell migration and cell-cycle progression. Rac1 knockdown leads to significant inhibition of viral replication. In this work, we demonstrated that NDV treatment led to significant reduction of tumour tissue viability of freshly isolated heterogeneous human brain tumour slice, known as an ex vivo glioma acute slice (EGAS). Analysis of gene expression indicated that reduced tissue viability was associated with downregulation of Rac1. However, the viability reduction was not persistent. We conclude that NDV treatment induced EGAS viability suppression, but subsequent downregulation of Rac1 gene may reduce the NDV replication and lead to regrowth of EGAS tissue.
Loneliness as a risk factor for hypertension in later life

Momtaz YA, Hamid TA, Yusoff S, Ibrahim R, Chai ST, Yahaya N, et al.

J Aging Health, 2012 Jun;24(4):696-710.
PMID: 22422758 DOI: 10.1177/0898264311431305

The present study aims to determine the impact of loneliness on hypertension in later life.
Fulltext Moderating effect of Islamic religiosity on the relationship between chronic medical conditions and psychological well-being among elderly Malays

Abolfathi Momtaz Y, Hamid TA, Ibrahim R, Yahaya N, Abdullah SS

Psychogeriatrics, 2012 Mar;12(1):43-53.
PMID: 22416828 DOI: 10.1111/j.1479-8301.2011.00381.x

Research has found that physical health decline in later life is associated with poor psychological well-being. This study aimed to examine the possible moderating effect of Islamic religiosity on the relationship between chronic medical conditions and psychological well-being.
Fulltext Effects of acute gamma irradiation on physiological traits and flavonoid accumulation of Centella asiatica

Moghaddam SS, Jaafar H, Ibrahim R, Rahmat A, Aziz MA, Philip E

Molecules, 2011 Jun 17;16(6):4994-5007.
PMID: 21694666 DOI: 10.3390/molecules16064994

In the present study, two accessions of Centella asiatica (CA03 and CA23) were subjected to gamma radiation to examine the response of these accessions in terms of survival rate, flavonoid contents, leaf gas exchange and leaf mass. Radiation Sensitivity Tests revealed that based on the survival rate, the LD(50) (gamma doses that killed 50% of the plantlets) of the plantlets were achieved at 60 Gy for CA03 and 40 Gy for CA23. The nodal segments were irradiated with gamma rays at does of 30 and 40 Gy for Centella asiatica accession 'CA03' and 20 and 30 Gy for accession 'CA23. The nodal segment response to the radiation was evaluated by recording the flavonoid content, leaf gas exchange and leaf biomass. The experiment was designed as RCBD with five replications. Results demonstrated that the irradiated plantlets exhibited greater total flavonoid contents (in eight weeks) significantly than the control where the control also exhibited the highest total flavonoid contents in the sixth week of growth; 2.64 ± 0.02 mg/g DW in CA03 and 8.94 ± 0.04 mg/g DW in CA23. The total flavonoid content was found to be highest after eight weeks of growth, and this, accordingly, stands as the best time for leaf harvest. Biochemical differentiation based on total flavonoid content revealed that irradiated plantlets in CA23 at 20 and 30 Gy after eight weeks contained the highest total flavonoid concentrations (16.827 ± 0.02; 16.837 ± 0.008 mg/g DW, respectively) whereas in CA03 exposed to 30 and 40 Gy was found to have the lowest total flavonid content (5.83 ± 0.11; 5.75 ± 0.03 mg/g DW). Based on the results gathered in this study, significant differences were found between irradiated accessions and control ones in relation to the leaf gas. The highest PN and gs were detected in CA23 as control followed by CA23 irradiated to 20Gy (CA23G20) and CA23G30 and the lowest PN and gs were observed in CA03 irradiated to 40Gy (CA03G40). Moreover, there were no significant differences in terms of PN and gs among the irradiated plants in each accession. The WUE of both irradiated accessions of Centella asiatica were reduced as compared with the control plants (p < 0.01) while Ci and E were enhanced. There were no significant differences in the gas exchange parameters among radiated plants in each accession. Moreover, malondialdehyde (MDA) of accessions after gamma treatments were significantly higher than the control, however, flavonoids which were higher concentration in irradiated plants can scavenge surplus free radicals. Therefore, the findings of this study have proven an efficient method of in vitro mutagenesis through gamma radiation based on the pharmaceutical demand to create economically superior mutants of C. asiatica. In other words, the results of this study suggest that gamma irradiation on C. asiatica can produce mutants of agricultural and economical importance.
Fulltext Flavonoid and leaf gas exchange responses of Centella asiatica to acute gamma irradiation and carbon dioxide enrichment under controlled environment conditions

Moghaddam SS, Jaafar HB, Aziz MA, Ibrahim R, Rahmat AB, Philip E

Molecules, 2011 Oct 25;16(11):8930-44.
PMID: 22027950 DOI: 10.3390/molecules16118930

The study was couducted to investigate the effects of gamma irradiation and CO₂ on flavonoid content and leaf gas exchange in C.asiatica. For flavonoid determination, the design was a split split plot based on Randomized Complete Block Design (RCBD). For other parameters, the designs were split plots. Statistical tests revealed significant differences in flavonoid contents of Centella asiatica leaves between different growth stages and various CO₂ treatments. CO₂ 400, G20 (400 = ambient CO₂; G20 = Plants exposed to 20 Gy) showed 82.90% higher total flavonoid content (TFC) in the 5th week than CO₂ 400 as control at its best harvest time (4th week). Increasing the concentration of CO₂ from 400 to 800 μmol/mol had significant effects on TFC and harvesting time. In fact, 800 μmol/mol resulted in 171.1% and 66.62% increases in TFC for control and irradiated plants, respectively. Moreover, increasing CO₂ concentration reduced the harvesting time to three and four weeks for control and irradiated plants, respectively. Enhancing CO₂ to 800 µmol/mol resulted in a 193.30% (CO₂ 800) increase in leaf biomass compared to 400 µmol/mol and 226.34% enhancement in irradiated plants (CO₂ 800, G20) [800 = Ambient CO₂; G20 = Plants exposed to 20 Gy] than CO₂ 400, G20. In addition, the CO₂ 800, G20 had the highest amount of flavonoid*biomass in the 4th week. The results of this study indicated that all elevated CO₂ treatments had higher PN than the ambient ones. The findings showed that when CO₂ level increased from 400 to 800 µmol/mol, stomatal conductance, leaf intercellular CO₂ and transpiration rate had the tendency to decrease. However, water use efficiency increased in response to elevated CO₂ concentration. Returning to the findings of this study, it is now possible to state that the proposed method (combined CO₂ and gamma irradiation) has the potential to increase the product value by reducing the time to harvest, increasing the yield per unit area via boosting photosynthesis capacity, as well as increasing biochemicals (flavonoids) per gram DM.
Optimization of an efficient semi-solid culture protocol for sterilization and plant regeneration of Centella asiatica (L.) as a medicinal herb

Moghaddam SS, Jaafar HB, Aziz MA, Ibrahim R, Rahmat AB, Philip E

Molecules, 2011;16(11):8981-91.
PMID: 22439138

The present study investigates the effects of different concentrations, as well as type of plant growth regulators (PGRs) and medium (MS, Duchefa) on the growth and development of Centella asiatica in semi-solid culture. In addition, a protocol for successful sterilization of C.asiatica explants prepared from field-grown plants highly exposed to fungal and bacterial contamination was determined. Results for sterilization treatments revealed that applying HgCl₂ and Plant Preservative Mixture (PPM) with cetrimide, bavistin and trimethoprim which were included after washing with tap water, followed by the addition of PPM in the medium, produced a very satisfactory result (clean culture 90 ± 1.33%) and TS5 (decon + cetrimide 1% + bavistin 150 mg/L + trimethoprim 50 mg/L + HgCl₂0.1% + PPM 2% soak and 2 mL/L in medium) was hence chosen as the best method of sterilization for C.asiatica. The synergistic combination of 6 benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) in concentrations of 2 mg/L and 0.1 mg/L, respectively, in Duchefa medium compared with MS induced the most optimal percentage of sprouted shoots (93 ± 0.667), number of shoots (5.2 ± 0.079) and nodes (4 ± 0.067) per explant, leaf per explant (14 ± 0.107) and shoot length (4.1 ± 0.67 cm). Furthermore, optimum rooting frequency (95.2 ± 0.81%), the number of roots/shoot (7.5 ± 0.107) and the mean root length (4.5 ± 0.133 cm) occurred for shoots that were cultured on full-strength MS medium containing 0.5 mg/L indole-3-butyric acid (IBA). In this study, the acclimatized plantlets were successfully established with almost 85% survival. The findings of this study have proven an efficient medium and PGR concentration for the mass propagation of C.asiatica. These findings would be useful in micropropagation and ex situ conservation of this plant.
Newcastle diseases virus strain V4UPM displayed oncolytic ability against experimental human malignant glioma

Zulkifli MM, Ibrahim R, Ali AM, Aini I, Jaafar H, Hilda SS, et al.

Neurol Res, 2009 Feb;31(1):3-10.
PMID: 18937888 DOI: 10.1179/174313208X325218

Newcastle disease virus (NDV) is a virus of paramyxovirus family and lately has been studied for the treatment of cancer in human. In this study, we successfully determined the oncolysis potential of NDV vaccine, V4UPM tested on the human glioblastoma multiform cell line (DBTRG.05MG) and human glioblastoma astrocytoma cell line (U-87MG) in vitro and in vivo. The V4UPM strain is a modified V4 strain developed as thermostable feed pellet vaccine for poultry.

Filters

Please provide feedback to Administrator ([email protected])

External Links