Displaying publications 61 - 71 of 71 in total

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  1. Hai T, El-Shafay AS, Goyal V, Alshahri AH, Almujibah HR
    Chemosphere, 2023 Sep 01.
    PMID: 37660791 DOI: 10.1016/j.chemosphere.2023.139782
    Considering the persistent human need for electricity and fresh water, cogeneration systems based on the production of these two products have attracted the attention of researchers. This study investigates a cogeneration system of electricity and fresh water based on gas turbine (GT) as the prime mover. The wasted energy of the GT exhaust gases is absorbed by a heat recovery steam generator (HRSG) and supplies the superheat steam required by the steam turbine (ST). In order to produce fresh water, a multi-effect desalination (MED) system is applied. The motive steam required is provided by extracting steam from the ST. In order to reduce the environmental pollution of this cogeneration system, the steam injection method is proposed in the GT's combustion chamber (CC). This system is optimized by a multi-objective optimization tool based on the Genetic Algorithm (GA). The design variables include pressure ratio of compressor (CPR), inlet temperature of gas turbine (TIT), steam injection mass flow rate in the CC, HRSG operating pressure, HRSG evaporator pinch point temperature difference (PPTD), steam pressure of the MED ejector, ejector motive steam flow rate, number of MED effects, and return effect. The goals are to minimize the total cost rate (TCR), which includes the cost of initial investment and maintenance of the system, the cost of consumed fuel, and the cost of disposing of CO and NO pollutants, as well as maximizing the exergy efficiency. In the end, it is observed that the steam injection in the CC leads to the reduction of the mentioned pollutant index, and it is proposed as a suitable solution to reduce the pollution of the proposed cogeneration system.
  2. Abdullah H, Pihie AHL, Hohmann J, Molnár J
    Cancer Cell Int, 2010 May 04;10:14.
    PMID: 20441573 DOI: 10.1186/1475-2867-10-14
    BACKGROUND: Hydnophytum formicarium Jack is an epyphytic shrub that belongs to the family of Rubiaceae and is native to the tropical rain forests of the Asean region, which includes Malaysia. A flavanoid derivative, 7, 3', 5'-trihydroxyflavanone (3HFD), isolated from H. formicarium has been reported to have cytotoxic effects on the human breast carcinoma cell line MCF-7. The aim of the current study was to investigate the mode of cell death in MCF-7 cells treated with 3HFD. A DNA fragmentation assay was conducted on isolated genomic DNA, a TUNEL assay was used to determine the mode of cell death and Western blotting was used to evaluate the expression levels of Bax and Bcl-2. Immunofluorescence staining of MCF-7 cells was also performed to confirm the up-regulation of the Bax protein.

    RESULTS: The ladder pattern resulting from the DNA fragmentation assay was a multimer of 180 kb. The morphological changes of cells undergoing apoptosis were visualised by a TUNEL assay over time. The percentage of apoptotic cells increased as early as 6 hours post treatment compared to untreated cells. Western blotting revealed up-regulation of the pro-apoptotic protein Bax. However, 3HFD did not affect expression of the anti-apoptotic protein Bcl-2.

    CONCLUSIONS: Our results provide evidence that plant-derived 3HFD was able to induce the apoptotic cell death of MCF-7 cells by increasing Bax expression level and makes 3HFD a promising agent for chemotherapy, which merits further study.

  3. Abd Rashid N, Hapidin H, Abdullah H, Ismail Z, Long I
    Brain Behav, 2017 06;7(6):e00704.
    PMID: 28638710 DOI: 10.1002/brb3.704
    INTRODUCTION: REM sleep deprivation is associated with impairment in learning and memory, and nicotine treatment has been shown to attenuate this effect. Recent studies have demonstrated the importance of DREAM protein in learning and memory processes. This study investigates the association of DREAM protein in REM sleep-deprived rats hippocampus upon nicotine treatment.

    METHODS: Male Sprague Dawley rats were subjected to normal condition, REM sleep deprivation and control wide platform condition for 72 hr. During this procedure, saline or nicotine (1 mg/kg) was given subcutaneously twice a day. Then, Morris water maze (MWM) test was used to assess learning and memory performance of the rats. The rats were sacrificed and the brain was harvested for immunohistochemistry and Western blot analysis.

    RESULTS: MWM test found that REM sleep deprivation significantly impaired learning and memory performance without defect in locomotor function associated with a significant increase in hippocampus DREAM protein expression in CA1, CA2, CA3, and DG regions and the mean relative level of DREAM protein compared to other experimental groups. Treatment with acute nicotine significantly prevented these effects and decreased expression of DREAM protein in all the hippocampus regions but only slightly reduce the mean relative level of DREAM protein.

    CONCLUSION: This study suggests that changes in DREAM protein expression in CA1, CA2, CA3, and DG regions of rat's hippocampus and mean relative level of DREAM protein may involve in the mechanism of nicotine treatment-prevented REM sleep deprivation-induced learning and memory impairment in rats.

  4. Badran MM, Alomrani AH, Harisa GI, Ashour AE, Kumar A, Yassin AE
    Biomed Pharmacother, 2018 Oct;106:1461-1468.
    PMID: 30119220 DOI: 10.1016/j.biopha.2018.07.102
    In the present study, docetaxel (DTX)-loaded poly(lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) nanoparticles were successfully prepared and coated with chitosan (CS). The prepared nanoparticles (NPs) were evaluated for their particle size, zeta potential, particle morphology, drug entrapment efficiency (EE%), and in vitro drug release profile. The anticancer activity of DTX-loaded NPs was assessed in human HT29 colon cancer cell line utilizing MTT assay. The pharmacokinetics of DTX-loaded NPs was monitored in Wistar rats in comparison to DTX solution. The prepared NPs exhibited particle sizes in the range 177.1 ± 8.2-287.6 ± 14.3 nm. CS decorated NPs exhibited a significant increase in particle size and a switch of zeta potential from negative to positive. In addition, high EE% values were obtained for CS coated PCL NPs and PLGA NPs as 67.1 and 76.2%, respectively. Moreover, lowering the rate of DTX in vitro release was achieved within 48 h by using CS coated NPs. Furthermore, a tremendous increase in DTX cytotoxicity was observed by CS-decorated PLGA NPs compared to all other NPs including DTX-free-NPs and pure DTX. The in vivo study revealed significant enhancement in DTX bioavailability from CS-decorated PLGA NPs with more than 4-fold increase in AUC compared to DTX solution. In conclusion, CS-decorated PLGA NPs are a considerable DTX-delivery carrier with magnificent antitumor efficacy.
  5. Abdullah H, Jiyen K, Othman N
    BMJ Case Rep, 2017 Sep 27;2017.
    PMID: 28954754 DOI: 10.1136/bcr-2017-221466
    We present a case of a 20-year-old Malay man with underlying tuberculous (TB) lymphadenitis who presented with shortness of breath and found to have submitral left ventricular aneurysm (SLVA). SLVA is well recognised but rare. Incidence of SLVA in Malay has never been documented. This is the first reported case of SLVA in Malays with concomitant thoracic aorta mycotic aneurysm. TB has been reported to be associated with SLVA. Treatment is either surgical or conservative. Imaging is required for diagnosis and preoperative assessment. Multimodality imaging include echocardiography (ECHO), cardiac CTangiography and the robust multiparametric cardiac MR (CMR). ECHO is the first line imaging and useful for initial detection of the aneurysm. CMR including the late gadolinium enhancement allows excellent visualisation of the LV aneurysm, tissue characterisation, cardiac function and detection of associated pathology as shown in this case.
  6. Fadhullah W, Imran NIN, Ismail SNS, Jaafar MH, Abdullah H
    BMC Public Health, 2022 Jan 05;22(1):1.
    PMID: 34983455 DOI: 10.1186/s12889-021-12274-7
    BACKGROUND: Poor waste disposal practices hamper the progress towards an integrated solid waste management in households. Knowledge of current practices and perception of household solid waste management is necessary for accurate decision making in the move towards a more sustainable approach. This study investigates the household waste practices and perceptions about waste management in Panji, one of the sub-districts in Kota Bharu, Kelantan, Malaysia.

    METHODS: A stratified random sampling technique using a cross-sectional survey questionnaire was used to collect data. A total of 338 households were interviewed in the survey and data were analyzed using SPSS. Chi-square goodness of fit test was used to determine the relationships between categorical variables, whereas Chi-square bivariate correlation test was performed to observe the correlation between the perceptions of waste segregation with socio-demographic background of the respondents. The correlation between perception of respondents with the locality, house type and waste type were also conducted. Principal component analysis was used to identify grouping of variables and to establish which factors were interrelated in any given construct.

    RESULTS: The results of the study revealed that 74.3 % of households disposed of food debris as waste and 18.3% disposed of plastic materials as waste. The study also showed that 50.3% of the households segregate their waste while 49.7% did not. About 95.9% of the respondents were aware that improper waste management leads to disease; such as diarrhea and malaria. There were associations between locality, age and house type with waste segregation practices among respondents (Chi-square test, p<0.05). Associations were also found between locality with the perception of improper waste management which lead to disease (Chi-square test, p<0.05). Principal Component Analysis showed that 17.94% of the variance has high positive loading (positive relationship) with age, marital status and, type of house.

    CONCLUSION: This study highlights the importance to design waste separation programs that suit the needs of targeted population as a boost towards sustainable solid waste management practices.

  7. Abdullah H, Pearson GJ
    Asian J Aesthet Dent, 1993 Jul;1(2):91-4.
    PMID: 7921802
    The effect of temperature change on the working and setting time of a glass ionomer luting cement and a resin luting cement was measured using the oscillating rheometer. The time taken for each cement to set was calculated from the chart recordings. It was observed that as the temperature increased, the working and setting time of both materials decreased. However, the reduction was much more marked for the dual curing resin cement.
  8. Annuar, W.A., Abdullah, H.
    Ann Dent, 2003;10(1):-.
    MyJurnal
    This study is conducted to compare two resin luting cements (Rely XTMARC,3M and Compolute™ESPE) on their microleakage with one composite inlay system (Filtek™ Z250 Universal Restorative Materials, 3M). Thirty conventional inlays, Class II MOIDO cavity with gingival margin I mm above the cementoenamel junction, were prepared in premolar teeth. The composite inlays were fabricated directly on the prepared teeth using layering technique. Fifteen of the inlays were cemented with RelyTMX ARC and fifteen with Compolute™ (ESPE). The specimens were kept at 370 C for 10 days before thermocycling and immersed in methylene blue 2% solution for 24 hours. The teeth were sectioned mesio-distally. The site and degree of leakage of each section was scored using a visual scoring system under a stereomicroscope at a magnification of 1.5X. Results showed that there was no significant difference in'leakage extent (p>O.05), between Rely X™ARC and Compolute™. For both materials, leakage occurred most commonly within the enamel surface and between the cement-tooth interfaces. None of the leakage occurred between inlay - cement interface. There is no significant difference in the extent of leakage between Rely XTMARC compared to Compolute™.
  9. Hesham Al-Mekhlafi M, Surin J, Atiya AS, Ariffin WA, Mohammed Mahdy AK, Che Abdullah H
    Acta Trop, 2008 Aug;107(2):200-4.
    PMID: 18582430 DOI: 10.1016/j.actatropica.2008.05.022
    Data on soil-transmitted helminth (STH) infections and reinfection among Orang Asli (aborigine) schoolchildren and their nutritional and socioeconomic status were analyzed to investigate the pattern and the possible predictors of STH reinfection. In this longitudinal study, 120 (60 males and 60 females) Orang Asli primary schoolchildren aged 7-12 years and living in remote areas in Pos Betau, Kuala Lipis, Pahang were screened for the presence of STH using modified cellophane thick smear and Harada Mori techniques. The overall prevalence of ascariasis, trichuriasis and hookworm infections were 65.8, 97.5 and 10.8%, respectively. After complete deworming with a 3-day course of 400mg/daily of albendazole tablets, children were re-examined at 3 and 6 months from baseline. The reinfection rate, by one or more of STH species, at 3 months after deworming was high (49.5%) while 79.6% of the children were reinfected at 6 months after deworming. Logistic regression analyses showed that females, stunted children and those living in houses without toilets had significantly higher reinfection rates than others at 3 months (P<0.05). At 6 months, maternal employment status emerged as another predictor where children of working mothers had significantly higher reinfection rates (P=0.026). In conclusion, reinfection rate of STH is high and thus necessitates frequent and periodic deworming among children. Public health personnel need to re-look at the current control measures and identify innovative and integrated ways in order to reduce STH significantly in the rural communities.
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