Displaying publications 181 - 200 of 280 in total

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  1. Fulltext Bacterial communities associated with silage of different forage crops in Malaysian climate analysed using 16S amplicon metagenomics
    Hisham MB, Hashim AM, Mohd Hanafi N, Abdul Rahman N, Abdul Mutalib NE, Tan CK, et al.
    Sci Rep, 2022 May 02;12(1):7107.
    PMID: 35501317 DOI: 10.1038/s41598-022-08819-4
    Silage produced in tropical countries is prone to spoilage because of high humidity and temperature. Therefore, determining indigenous bacteria as potential inoculants is important to improve silage quality. This study aimed to determine bacterial community and functional changes associated with ensiling using amplicon metagenomics and to predict potential bacterial additives associated with silage quality in the Malaysian climate. Silages of two forage crops (sweet corn and Napier) were prepared, and their fermentation properties and functional bacterial communities were analysed. After ensiling, both silages were predominated by lactic acid bacteria (LAB), and they exhibited good silage quality with significant increment in lactic acid, reductions in pH and water-soluble carbohydrates, low level of acetic acid and the absence of propionic and butyric acid. LAB consortia consisting of homolactic and heterolactic species were proposed to be the potential bacterial additives for sweet corn and Napier silage fermentation. Tax4fun functional prediction revealed metabolic pathways related to fermentation activities (bacterial division, carbohydrate transport and catabolism, and secondary metabolite production) were enriched in ensiled crops (p 
  2. Delineating risk zones and evaluation of shelter centres for flood disaster management along the Pahang River Basin, Malaysia
    Isahak A, Reza MIH, Siwar C, Ismail SM, Sulaiman N, Hanafi Z, et al.
    Jamba, 2018;10(1):501.
    PMID: 29955268 DOI: 10.4102/jamba.v10i1.501
    Shelter centres are important locations to safeguard people from helpless situations and are an integral part of disaster risk reduction (DRR), particularly for flood DRR. The establishment of shelter centres, and their design based on scientific assessment, is crucial. Yet, they are very much related to the geographic location, socio-economic conditions and the livelihoods of the affected communities. However, many parts of the developing world are still lagging behind in ensuring such scientific design. Considering the flood disaster in 2014 that affected the residents living along the Pahang River Basin, in this study we delineate the communities at risk and evaluate the existing shelter centres to determine how they reduce people's vulnerability to the risks associated with rural and urban landscapes. We used spatial analysis tools to delineate risk zones and to evaluate existing evacuation systems. A flood disaster risk map was produced to determine which communities are living with risks. Subsequently, the distribution of shelter centres examined whether they are able to support people living at the flood risk zones. These centres were also evaluated using a set of international guidelines for effective disaster shelters. This reveals that the number of shelter centres is not adequate. The designation and designing of shelter centres are not being done scientifically. The maps produced here have a lot of potential to support disaster management decisions, in particular site selection and the prioritisation of centres. The study concludes with a set of guidelines and recommendations for structural and non-structural measures, such as alternative livelihoods and the potential of ecotourism, which may improve the resilience among flood-affected communities; and the decision-making process for the overall flood DRR initiatives.
  3. Fulltext Isolation of nucleated red blood cell from peripheral blood of β-Thalassemia major patients using CD71 magnetic beads and future application
    Haiyuni, M.Y., Aziee S., Heba A., Rosline H., Abdullah W.Z., Johan M.F., et al.
    Journal of Biomedical and Clinical Sciences, 2018;3(1):25-30.
    MyJurnal
    Introduction: Isolation of specific cell types is important in providing a better understanding of hematological disorders. The knowledge of molecular biology aspect in β-thalassemia is still limited. This is because hemoglobin disorder involves various erythropoietic processes in which the genetic information is lack due to enucleation of red blood cells occurs in bone marrow. It is invasive to collect samples from bone marrow and cord blood although nucleated red blood cells (NRBCs) are abundant in these sites. NRBCs are precursors of red blood cells and typically found in peripheral blood (PB) of β-thalassemia major patients and abundant post-splenectomy. The utilization of PB NRBCs will provide a further understanding of the molecular aspects of ineffective erythropoiesis in β-thalassemia major patients. Objective: The objective of this study was to isolate the NRBCs using CD71 magnetic beads from PB of β-thalassemia major; non-splenectomy and post-splenectomy patients. Methods: NRBCs were isolated from 6 mL PB of β-thalassemia major patients based on density gradient and magnetic activated cell sorting (MACS) for NRBCs enrichment using a CD71 marker. Cell count was determined by using hemocytometer (Weber Scientific, NJ, USA) and BD FACSCantoTM II flow cytometry (Becton-Dickson, NJ, USA) was performed for method validation. Results: NRBCs were successfully isolated from the PB of both non-splenectomy and post-splenectomy β-thalassemia major patients with >90% specificity by flow cytometric analysis. The median number of enriched NRBCs (x104 ) was 58.5 (283) and 340 (338) respectively using hemocytometer. Conclusion: The MACS method was found to be convenient and efficient in the isolation of the targeted cells for downstream applications.
  4. Kajian sifat mekanik nanokomposit epoksi berpenguat gentian hibrid nanotiub karbon dan nanozarah tanah liat
    Mohd Hafizuddin Ab Ghani, Mohd Nazry Salleh, Chen RS, Sahrim Ahmad, Ismail Hanafi, Nishata Royan Rajendran Royan, et al.
    Sains Malaysiana, 2016;45:1259-1263.
    Penyelidikan ini dijalankan bagi mengkaji sifat mekanik nanokomposit epoksi berpenguat gentian hibrid nano tiub
    karbon berbilang dinding (MWCNT) dan nanozarah tanah liat (NC). Nanokomposit berpenguat hibrid nanozarah telah
    disediakan melalui kaedah kacauan mekanik dan sampel dengan jumlah nanozarah berbeza dibentuk menggunakan
    pengacuan mampatan. Dalam ujian lenturan yang dijalankan, didapati sampel hibrid memberikan nilai kekuatan
    yang lebih tinggi berbanding sampel tunggal. Ujian terhadap sifat hentaman nanokomposit epoksi berpenguat gentian
    nanozarah menunjukkan bahawa penambahan gentian terhadap sampel tidak dapat meningkatkan sifat ketahanan daya
    hentaman yang dikenakan. Namun demikian, sampel yang mengandungi gentian hibrid nano merekodkan nilai daya
    tahan hentaman yang lebih tinggi berbanding sampel tunggal. Mikrograf pengimbas elektron (SEM) mengesahkan kesan
    serakan pengisi hibrid dan ikatan antara muka dalam matriks yang baik. Ini membuktikan bahawa gentian hibrid antara
    nanotiub karbon dan nanozarah tanah liat pada kandungan komposisi tertentu dapat menambahbaik sifat mekanik
    bahan nanokomposit.
  5. Effect of biphasic calcium phosphate scaffold porosities on odontogenic differentiation of human dental pulp cells
    AbdulQader ST, Rahman IA, Thirumulu KP, Ismail H, Mahmood Z
    J Biomater Appl, 2016 Apr;30(9):1300-11.
    PMID: 26740503 DOI: 10.1177/0885328215625759
    Calcium phosphates (CaP) of different porosities have been widely and successfully used as scaffolds with osteoblast cells for bone tissue regeneration. However, the effects of scaffold porosities on cell viability and differentiation of human dental pulp cells for dentin tissue regeneration are not well known. In this study, biphasic calcium phosphate (BCP) scaffolds of 20/80 hydroxyapatite to beta tricalcium phosphate ratio with a mean pore size of 300 μm were prepared into BCP1, BCP2, BCP3, and BCP4 of 25%, 50%, 65%, and 75% of total porosities, respectively. The extracts of these scaffolds were assessed with regard to cell viability, proliferation, and differentiation of human dental pulp cells. The high alkalinity, and more calcium and phosphate ions release that were exhibited by BCP3 and BCP4 decreased the viability and proliferation of human dental pulp cells as compared to BCP1 and BCP2. BCP2 significantly increased both cell viability and cell proliferation. However, the cells cultured with BCP3 extract revealed high alkaline phosphatase (ALP) activity and high expression of odontoblast related genes, collagen type I alpha 1, dentin matrix protein-1, and dentin sialophosphoprotein as compared to that cultured with BCP1, BCP2, and BCP4 extracts. The results highlight the effect of different scaffold porosities on the cell microenvironment and demonstrate that BCP3 scaffold of 65% porosity can support human dental pulp cells differentiation for dentin tissue regeneration.
  6. Effect of different calcium phosphate scaffold ratios on odontogenic differentiation of human dental pulp cells
    AbdulQader ST, Kannan TP, Rahman IA, Ismail H, Mahmood Z
    Mater Sci Eng C Mater Biol Appl, 2015 Apr;49:225-233.
    PMID: 25686943 DOI: 10.1016/j.msec.2014.12.070
    Calcium phosphate (CaP) scaffolds have been widely and successfully used with osteoblast cells for bone tissue regeneration. However, it is necessary to investigate the effects of these scaffolds on odontoblast cells' proliferation and differentiation for dentin tissue regeneration. In this study, three different hydroxyapatite (HA) to beta tricalcium phosphate (β-TCP) ratios of biphasic calcium phosphate (BCP) scaffolds, BCP20, BCP50, and BCP80, with a mean pore size of 300μm and 65% porosity were prepared from phosphoric acid (H2PO4) and calcium carbonate (CaCO3) sintered at 1000°C for 2h. The extracts of these scaffolds were assessed with regard to cell viability and differentiation of odontoblasts. The high alkalinity, more calcium, and phosphate ions released that were exhibited by BCP20 decreased the viability of human dental pulp cells (HDPCs) as compared to BCP50 and BCP80. However, the cells cultured with BCP20 extract expressed high alkaline phosphatase activity and high expression level of bone sialoprotein (BSP), dental matrix protein-1 (DMP-1), and dentin sialophosphoprotein (DSPP) genes as compared to that cultured with BCP50 and BCP80 extracts. The results highlighted the effect of different scaffold ratios on the cell microenvironment and demonstrated that BCP20 scaffold can support HDPC differentiation for dentin tissue regeneration.
  7. Applied K fertilizer use efficiency in pineapples grown on a tropical peat soil under residues removal
    Ahmed OH, Ahmad HM, Musa HM, Rahim AA, Rastan SO
    ScientificWorldJournal, 2005 Jan 21;5:42-9.
    PMID: 15674449
    In Malaysia, pineapples are grown on peat soils, but most K fertilizer recommendations do not take into account K loss through leaching. The objective of this study was to determine applied K use efficiency under a conventionally recommended fertilization regime in pineapple cultivation with residues removal. Results showed that K recovery from applied K fertilizer in pineapple cultivation on tropical peat soil was low, estimated at 28%. At a depth of 0-10 cm, there was a sharp decrease of soil total K, exchangeable K, and soil solution K days after planting (DAP) for plots with K fertilizer. This decline continued until the end of the study. Soil total, exchangeable, and solution K at the end of the study were generally lower than prior values before the study. There was no significant accumulation of K at depths of 10-25 and 25-45 cm. However, K concentrations throughout the study period were generally lower or equal to their initial status in the soil indicating leaching of the applied K and partly explained the low K recovery. Potassium losses through leaching in pineapple cultivation on tropical peat soils need to be considered in fertilizer recommendations for efficient recovery of applied K.
  8. Effects of sevoflurane increments on left ventricular systolic long-axis performance during sevoflurane-remifentanil anesthesia for cardiovascular surgery
    Kwon WK, Sung TY, Yu GY, Sidik H, Kang WS, Lee Y, et al.
    J Anesth, 2016 Apr;30(2):223-31.
    PMID: 26577248 DOI: 10.1007/s00540-015-2094-9
    BACKGROUND: The direct impact of sevoflurane on intraoperative left ventricular (LV) systolic performance during cardiac surgery has not been fully elucidated. Peak systolic tissue Doppler velocities of the lateral mitral annulus (S') have been used to evaluate LV systolic long-axis performance. We hypothesized that incremental sevoflurane concentration (1.0-3.0 inspired-vol%) would dose-dependently reduce S' in patients undergoing cardiac surgery due to mitral or aortic insufficiency.

    METHODS: In 20 patients undergoing cardiac surgery in sevoflurane-remifentanil anesthesia, we analyzed intraoperative S' values which were determined after 10 min exposure to sevoflurane at 1.0, 2.0, and 3.0 inspired-vol% (T1, T2, and T3, respectively) with a fixed remifentanil dose (1.0 μg/kg/min) using transesophageal echocardiography.

    RESULTS: Linear mixed-effect modeling demonstrated dose-dependent declines in S' according to the end-tidal sevoflurane concentration increments (C(ET)-sevoflurane, p < 0.001): the mean value of S' reduction for each 1.0 vol%-increment of C(ET)-sevoflurane was 1.7 cm/s (95 % confidence interval 1.4-2.1 cm/s). Medians of S' at T1, T2, and T3 (9.6, 8.9, and 7.5 cm/s, respectively) also exhibited significant declines (by 6.6, 15.6, and 21.2 % for T1 vs. T2, T2 vs. T3, and T1 vs. T3, p < 0.001, =0.002, and <0.001 in Friedman pairwise comparisons, respectively).

    CONCLUSIONS: Administering sevoflurane as a part of a sevoflurane-remifentanil anesthesia regimen appears to dose-dependently reduce S', indicating LV systolic performance, in patients undergoing cardiac surgery. Further studies may be required to evaluate the clinical implications of these findings.

  9. Antioxidant modulation in restoring mitochondrial function in neurodegeneration
    Pahrudin Arrozi A, Wan Ngah WZ, Mohd Yusof YA, Ahmad Damanhuri MH, Makpol S
    Int J Neurosci, 2017 Mar;127(3):218-235.
    PMID: 27074540 DOI: 10.1080/00207454.2016.1178261
    Alzheimer's disease (AD) and Parkinson's disease (PD) are the leading causes of disability associated with neurodegeneration worldwide. These diseases are influenced by multiple genetic and environmental factors and share similar mechanisms as both are characterized by accumulation and aggregation of misfolded proteins - amyloid-beta (Aβ) in AD and α-synuclein in PD. Over the past decade, increasing evidence has shown that mitochondrial dysfunction and the generation of reactive oxygen species (ROS) are involved in the pathology of these diseases, and the contributions of these defects to the cellular and molecular changes that eventually cause neuronal death have been explored. Using mitochondrial protective agents, such as antioxidants, to combat ROS provides a new strategy for neurodegenerative treatment. In this review, we highlight the potential of multiple types of antioxidants, including vitamins, phytochemicals, fatty acids and minerals, as well as synthetic antioxidants specifically targeting the mitochondria, which can restore mitochondrial function, in the treatment of neurodegenerative disorders at both the pre-clinical and clinical stages by focusing on AD and PD.
  10. Fulltext Perception of content and non-content expert facilitators of PBL according to students' performance levels
    Ismail NA, Alias E, Arifin KT, Damanhuri MH, Karim NA, Aan GJ
    Pak J Med Sci, 2015 Nov-Dec;31(6):1537-41.
    PMID: 26870131 DOI: 10.12669/pjms.316.8691
    Problem-based learning (PBL) is a student-centred learning system that involves multidisciplinary fields focused on problem solving. Facilitators of PBL are not necessarily content experts but little is known on how this concept has affected the outcomes of PBL sessions in learning Medical Biochemistry. We aimed to evaluate the impact of having the content expert as a facilitator in conducting PBL.
  11. Fulltext Tocotrienol Rich Fraction Supplementation Modulate Brain Hippocampal Gene Expression in APPswe/PS1dE9 Alzheimer's Disease Mouse Model
    Wan Nasri WN, Makpol S, Mazlan M, Tooyama I, Wan Ngah WZ, Damanhuri HA
    J Alzheimers Dis, 2019;70(s1):S239-S254.
    PMID: 30507571 DOI: 10.3233/JAD-180496
    Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by loss of memory and other cognitive abilities. AD is associated with aggregation of amyloid-β (Aβ) deposited in the hippocampal brain region. Our previous work has shown that tocotrienol rich fraction (TRF) supplementation was able to attenuate the blood oxidative status, improve behavior, and reduce fibrillary-type Aβ deposition in the hippocampus of an AD mouse model. In the present study, we investigate the effect of 6 months of TRF supplementation on transcriptome profile in the hippocampus of APPswe/PS1dE9 double transgenic mice. TRF supplementation can alleviate AD conditions by modulating several important genes in AD. Moreover, TRF supplementation attenuated the affected biological process and pathways that were upregulated in the AD mouse model. Our findings indicate that TRF supplementation can modulate hippocampal gene expression as well as biological processes that can potentially delay the progression of AD.
  12. Fulltext Preparation and Characterization of Low-Molecular-Weight Natural Rubber Latex via Photodegradation Catalyzed by Nano TiO₂
    Ibrahim S, Othman N, Sreekantan S, Tan KS, Mohd Nor Z, Ismail H
    Polymers (Basel), 2018 Nov 01;10(11).
    PMID: 30961141 DOI: 10.3390/polym10111216
    Natural rubber is one of the most important renewable biopolymers used in many applications due to its special properties that cannot be easily mimicked by synthetic polymers. To sustain the existence of natural rubber in industries, modifications have been made to its chemical structure from time to time in order to obtain new properties and to enable it to be employed in new applications. The chemical structure of natural rubber can be modified by exposure to ultraviolet light to reduce its molecular weight. Under controlled conditions, the natural rubber chains will be broken by photodegradation to yield low-molecular-weight natural rubber. The aim of this work was to obtain what is known as liquid natural rubber via photodegradation, with titanium dioxide nanocrystals as the catalyst. Titanium dioxide, which was firstly synthesized using the sol⁻gel method, was confirmed to be in the form of an anatase, with a size of about 10 nm. In this work, the photodegradation was carried out in latex state and yielded low-molecular-weight natural rubber latex of less than 10,000 g/mol. The presence of hydroxyl and carbonyl groups on the liquid natural rubber (LNR) chains was observed, resulting from the breaking of the chains. Scanning electron microscopy of the NR latex particles showed that titanium dioxide nanocrystals were embedded on the latex surface, but then detached during the degradation reaction.
  13. Fulltext Effect of Sago Starch Modifications on Polystyrene/Thermoplastic Starch Blends
    Ab Wahab MK, Mohamad HS, Jayamani E, Ismail H, Wnuk I, Przybył A, et al.
    Materials (Basel), 2021 May 27;14(11).
    PMID: 34071851 DOI: 10.3390/ma14112867
    The preparation of polystyrene/thermoplastic starch (PS/TPS) blends was divided into three stages. The first stage involved the preparation of TPS from sago starch. Then, for the second stage, PS was blended with TPS to produce a TPS/PS blend. The ratios of the TPS/PS blend were 20:80, 40:60, 60:40, and 80:20. The final stage was a modification of the composition of TPS/PS blends with succinic anhydride and ascorbic acid treatment. Both untreated and treated blends were characterized by their physical, thermal, and surface morphology properties. The obtained results indicate that modified blends have better tensile strength as the adhesion between TPS and PS was improved. This can be observed from SEM micrographs, as modified blends with succinic anhydride and ascorbic acid had smaller TPS dispersion in PS/TPS blends. The micrograph showed that there was no agglomeration and void formation in the TPS/PS blending process. Furthermore, modified blends show better thermal stability, as proved by thermogravimetric analysis. Water uptake into the TPS/PS blends also decreased after the modifications, and the structural analysis showed the formation of a new peak after the modification process.
  14. Correction to: Epidemiology, clinical characteristics, and immediate outcome of Kawasaki disease: a population-based study from a tropical country
    Mat Bah MN, Alias EY, Razak H, Sapian MH, Foo FH, Abdullah N
    Eur J Pediatr, 2021 Aug;180(8):2607.
    PMID: 34160651 DOI: 10.1007/s00431-021-04160-6
  15. Epidemiology, clinical characteristics, and immediate outcome of Kawasaki disease: a population-based study from a tropical country
    Mat Bah MN, Alias EY, Razak H, Sapian MH, Foo FH, Abdullah N
    Eur J Pediatr, 2021 Aug;180(8):2599-2606.
    PMID: 34086103 DOI: 10.1007/s00431-021-04135-7
    Data on Kawasaki disease from tropical countries are scarce. Hence, this population-based study aims to determine the epidemiology, clinical characteristics, and outcome of Kawasaki disease in children enrolled in the Kawasaki disease registry between 2006 and 2019 in Southern Malaysia. Diagnosis of Kawasaki disease was made using standard criteria. Primary outcome measure was a coronary artery aneurysm. Multivariable logistic regression was used to analyze the associated risk factors for coronary artery aneurysm. There were 661 Kawasaki disease, with 27% incomplete and 11% atypical presentations. Male-to-female ratio was 2:1, and median age of diagnosis was 1.4 years (interquartile range 9 to 32 months). Incidence in children of less than 5 years was 14.8 (95% confidence interval [CI]: 13.6 to 16.0) per 100,000 population, higher in males (19/100,000) and Chinese (22/100,000), with a gradual increase from 5.7/100,000 in 2006 to 19.6/100,000 in 2019, p < 0.001. Incidence in children between 5 and 9 years old was 1.3 (95% CI: 0.9 to 1.6) per 100,000 population and remained stable over time. There was a seasonal pattern with peak incidence during the rainy season. Out of 625 intravenous immunoglobulins (IVIG)-treated Kawasaki disease, 7.4% were resistant, and 9% had coronary artery aneurysms. Atypical presentation, male sex, late diagnosis, and IVIG resistance were independent risk factors for coronary artery aneurysms.Conclusions: Despite the tropical climate, Kawasaki disease epidemiology is similar to non-tropic regions with seasonal patterns and a rising incidence. Atypical presentation, male sex, late diagnosis, and IVIG resistance were significantly associated with coronary artery aneurysms. What is Known: • Kawasaki disease predominantly occurs in males, children less than 5 years old, and the Asian population. • Male sex, late diagnosis, incomplete Kawasaki disease, and IVIG resistance were associated with coronary artery aneurysms. What is New: • In multi-ethnic Asian countries such as Malaysia, ethnic Chinese have a higher prevalence of Kawasaki disease compared to other ethnicities. • Kawasaki disease with atypical presentation can occur in both complete and incomplete Kawasaki disease and is significantly associated with a coronary artery aneurysm.
  16. Fulltext Biomass and Habitat Characteristics of Epiphytic Macroalgae in the Sibuti Mangroves, Sarawak, Malaysia
    Isa HM, Kamal AH, Idris MH, Rosli Z, Ismail J
    Trop Life Sci Res, 2017 Jan;28(1):1-21.
    PMID: 28228913 MyJurnal DOI: 10.21315/tlsr2017.28.1.1
    Mangroves support diverse macroalgal assemblages as epibionts on their roots and tree trunks. These algae provide nutrients to the primary consumers in the aquatic food web and have been reported to be substantial contributors to marine ecosystems. The species diversity, biomass, and habitat characteristics of mangrove macroalgae were investigated at three stations in the Sibuti mangrove estuary, Sarawak, Malaysia, from November 2012 to October 2013. Three groups of macroalgae were recorded and were found to be growing on mangrove prop roots, namely Rhodophyta (Caloglossa ogasawaraensis, Caloglossa adhaerens, Caloglossa stipitata, Bostrychia anomala, and Hypnea sp.), Chlorophyta (Chaetomorpha minima and Chaetomorpha sp.), and Phaeophyta (Dictyota sp.). The biomass of macroalgae was not influenced (p>0.05) by the season in this mangrove forest habitat. The macroalgal species Hypnea sp. contributed the highest biomass at both Station 1 (210.56 mg/cm(2)) and Station 2 (141.72 mg/cm(2)), while the highest biomass was contributed by B. anomala (185.89 mg/cm(2)) at Station 3. This study shows that the species distribution and assemblages of mangrove macroalgae were influenced by environmental parameters such as water nutrients, dissolved solids, and salinity in the estuarine mangrove habitats of Sibuti, Sarawak.
  17. Fulltext Potency of Urea-Treated Halloysite Nanotubes for the Simultaneous Boosting of Mechanical Properties and Crystallization of Epoxidized Natural Rubber Composites
    Surya I, Waesateh K, Saiwari S, Ismail H, Othman N, Hayeemasae N
    Polymers (Basel), 2021 Sep 11;13(18).
    PMID: 34577969 DOI: 10.3390/polym13183068
    Halloysite nanotubes (HNTs) are naturally occurring tubular clay made of aluminosilicate sheets rolled several times. HNT has been used to reinforce many rubbers. However, the narrow diameter of this configuration causes HNT to have poor interfacial contact with the rubber matrix. Therefore, increasing the distance between layers could improve interfacial contact with the matrix. In this work, Epoxidized Natural Rubber (ENR)/HNT was the focus. The HNT layer distance was successfully increased by a urea-mechanochemical process. Attachment of urea onto HNT was verified by FTIR, where new peaks appeared around 3505 cm-1 and 3396 cm-1, corresponding to urea's functionalities. The intercalation of urea to the distance gallery of HNT was revealed by XRD. It was also found that the use of urea-treated HNT improved the modulus, tensile strength, and tear strength of the composites. This was clearly responsible for interactions between ENR and urea-treated HNT. It was further verified by observing the Payne effect. The value of the Payne effect was found to be reduced at 62.38% after using urea for treatment. As for the strain-induced crystallization (SIC) of the composites, the stress-strain curves correlated well with the results from synchrotron wide-angle X-ray scattering.
  18. Fulltext Statistical Modelling and Characterization of Experimental mm-Wave Indoor Channels for Future 5G Wireless Communication Networks
    Al-Samman AM, Rahman TA, Azmi MH, Hindia MN, Khan I, Hanafi E
    PLoS One, 2016 Sep 21;11(9):e0163034.
    PMID: 27654703 DOI: 10.1371/journal.pone.0163034
    This paper presents an experimental characterization of millimeter-wave (mm-wave) channels in the 6.5 GHz, 10.5 GHz, 15 GHz, 19 GHz, 28 GHz and 38 GHz frequency bands in an indoor corridor environment. More than 4,000 power delay profiles were measured across the bands using an omnidirectional transmitter antenna and a highly directional horn receiver antenna for both co- and cross-polarized antenna configurations. This paper develops a new path-loss model to account for the frequency attenuation with distance, which we term the frequency attenuation (FA) path-loss model and introduce a frequency-dependent attenuation factor. The large-scale path loss was characterized based on both new and well-known path-loss models. A general and less complex method is also proposed to estimate the cross-polarization discrimination (XPD) factor of close-in reference distance with the XPD (CIX) and ABG with the XPD (ABGX) path-loss models to avoid the computational complexity of minimum mean square error (MMSE) approach. Moreover, small-scale parameters such as root mean square (RMS) delay spread, mean excess (MN-EX) delay, dispersion factors and maximum excess (MAX-EX) delay parameters were used to characterize the multipath channel dispersion. Multiple statistical distributions for RMS delay spread were also investigated. The results show that our proposed models are simpler and more physically-based than other well-known models. The path-loss exponents for all studied models are smaller than that of the free-space model by values in the range of 0.1 to 1.4 for all measured frequencies. The RMS delay spread values varied between 0.2 ns and 13.8 ns, and the dispersion factor values were less than 1 for all measured frequencies. The exponential and Weibull probability distribution models best fit the RMS delay spread empirical distribution for all of the measured frequencies in all scenarios.
  19. Evaluation of the Expression of Amyloid Precursor Protein and the Ratio of Secreted Amyloid Beta 42 to Amyloid Beta 40 in SH-SY5Y Cells Stably Transfected with Wild-Type, Single-Mutant and Double-Mutant Forms of the APP Gene for the Study of Alzheimer's Disease Pathology
    Pahrudin Arrozi A, Shukri SNS, Wan Ngah WZ, Mohd Yusof YA, Ahmad Damanhuri MH, Makpol S
    Appl Biochem Biotechnol, 2017 Nov;183(3):853-866.
    PMID: 28417423 DOI: 10.1007/s12010-017-2468-6
    Neuroblastoma cell lines such as SH-SY5Y are the most frequently utilized models in neurodegenerative research, and their use has advanced the understanding of the pathology of neurodegeneration over the past few decades. In Alzheimer's disease (AD), several pathogenic mutations have been described, all of which cause elevated levels of pathological hallmarks such as amyloid-beta (Aβ). Although the genetics of Alzheimer's disease is well known, familial AD only accounts for a small number of cases in the population, with the rest being sporadic AD, which contains no known mutations. Currently, most of the in vitro models used to study AD pathogenesis only examine the level of Aβ42 as a confirmation of successful model generation and only perform comparisons between wild-type APP and single mutants of the APP gene. Recent findings have shown that the Aβ42/40 ratio in cerebrospinal fluid (CSF) is a better diagnostic indicator for AD patients than is Aβ42 alone and that more extensive Aβ formation, such as accumulation of intraneuronal Aβ, Aβ plaques, soluble oligomeric Aβ (oAβ), and insoluble fibrillar Aβ (fAβ) occurs in TgCRND8 mice expressing a double-mutant form (Swedish and Indiana) of APP, later leading to greater progressive impairment of the brain. In this study, we generated SH-SY5Y cells stably transfected separately with wild-type APP, the Swedish mutation of APP, and the Swedish and Indiana mutations of APP and evaluated the APP expression as well as the Aβ42/40 ratio in those cells. The double-mutant form of APP (Swedish/Indiana) expressed markedly high levels of APP protein and showed a high Aβ2/40 ratio compared to wild-type and single-mutant cells.
  20. Survival and Associated Risk Factors for Mortality Among Infants with Critical Congenital Heart Disease in a Developing Country
    Mat Bah MN, Sapian MH, Jamil MT, Alias A, Zahari N
    Pediatr Cardiol, 2018 Oct;39(7):1389-1396.
    PMID: 29756159 DOI: 10.1007/s00246-018-1908-6
    Critical congenital heart disease (CCHD) is associated with significant morbidity and mortality. However, data on survival of CCHD and the risk factors associated with its mortality are limited. This study examined CCHD survival and the risk factors for CCHD mortality. Using a retrospective cohort study of infants born with CCHD from 2006 to 2015, survival over 10 years was estimated using Kaplan-Meier analysis, and the risk factors for mortality were analyzed using multivariate Cox proportional hazards regression. A total of 491 CCHD cases were included in the study, with an overall mortality rate of 34.8% (95% confidence interval [CI] 30.6-39.2). The intervention/surgical mortality rate was 9.8% ≤ 30 days and 11.5% > 30 days after surgery, and 17% died before surgery or intervention. The median age at death was 2.7 months [first quartile: 1 month, third quartile: 7.3 months]. The CCHD survival rate was 90.4% (95% CI 89-91.8%) at 1 month, 69.3% (95% CI 67.2-71.4%) at 1 year, 63.4% (95% CI 61.1-65.7%) at 5 years, and 61.4% (95% CI 58.9-63.9%) at 10 years. Weight of
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