Displaying publications 1 - 20 of 31 in total

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  1. Azhar NA, Abu Bakar SA, Citartan M, Ahmad NH
    World J Hepatol, 2023 Mar 27;15(3):393-409.
    PMID: 37034237 DOI: 10.4254/wjh.v15.i3.393
    BACKGROUND: The demand for the development of cancer nanomedicine has increased due to its great therapeutic value that can overcome the limitations of conventional cancer therapy. However, the presence of various bioactive compounds in crude plant extracts used for the synthesis of silver nanoparticles (AgNPs) makes its precise mechanisms of action unclear.

    AIM: To assessed the mRNA transcriptome profiling of human HepG2 cells exposed to Catharanthus roseus G. Don (C. roseus)-AgNPs.

    METHODS: The proliferative activity of hepatocellular carcinoma (HepG2) and normal human liver (THLE3) cells treated with C. roseusAgNPs were measured using MTT assay. The RNA samples were extracted and sequenced using BGIseq500 platform. This is followed by data filtering, mapping, gene expression analysis, differentially expression genes analysis, Gene Ontology analysis, and pathway analysis.

    RESULTS: The mean IC50 values of C. roseusAgNPs on HepG2 was 4.38 ± 1.59 μg/mL while on THLE3 cells was 800 ± 1.55 μg/mL. Transcriptome profiling revealed an alteration of 296 genes. C. roseusAgNPs induced the expression of stress-associated genes such as MT, HSP and HMOX-1. Cellular signalling pathways were potentially activated through MAPK, TNF and TGF pathways that are responsible for apoptosis and cell cycle arrest. The alteration of ARF6, EHD2, FGFR3, RhoA, EEA1, VPS28, VPS25, and TSG101 indicated the uptake of C. roseus-AgNPs via both clathrin-dependent and clathrin-independent endocytosis.

    CONCLUSION: This study provides new insights into gene expression study of biosynthesised AgNPs on cancer cells. The cytotoxicity effect is mediated by the aberrant gene alteration, and more interestingly the unique selective antiproliferative properties indicate the C. roseusAgNPs as an ideal anticancer candidate.

  2. Ahmad NH, Rahim RA, Mat I
    Trop Life Sci Res, 2010 Dec;21(2):101-13.
    PMID: 24575203
    Research on natural products has been widely used as a strategy to discover new drugs with potential for applications in complementary medicines because they have fewer side effects than conventional drugs. The aim of the present study was to evaluate the in vitro cytotoxic effects of crude aqueous Catharanthus roseus extract on Jurkat cells and normal peripheral blood mononuclear cells (PBMCs). The aqueous extract was standardised to vinblastine by high performance liquid chromatography (HPLC) and was used to determine cytotoxicity by the MTS [3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay. DNA fragmentation assay was employed to determine if cell death was due to apoptosis. The results showed that the aqueous extract induced cell death of Jurkat cells at 24, 48 and 72 hours post-treatment in a time- and dose-dependent manner. However, cells treated at 48 and 72 hours produced higher cytotoxic effects with half maximal inhibitory concentration (IC50) values of 2.55 μg/ml and 2.38 μg/ml, respectively. In contrast, the extract induced normal PBMC proliferation, especially after 24 hours treatment with 1000 μg/ml. This result indicates that the C. roseus crude aqueous extract showed differential effects of inhibiting the proliferation of the Jurkat cell line and promoting the growth of PBMCs. These data suggest that the extract may be applicable for modulating the normal and transformed immune cells in leukaemia patients.
  3. Abdullah MR, Faizli AA, Noordin SS, Lee CJ, Ahmad NH
    Transfus Apher Sci, 2021 Jun;60(3):103076.
    PMID: 33574008 DOI: 10.1016/j.transci.2021.103076
    H-deficient phenotype individuals with absent or weak anti-H activity may remain undetected on standard routine blood grouping. We report a case of a 59-year-old-man presented with symptomatic anaemia secondary to upper gastrointestinal bleed with haemoglobin level of 68 g/L who required two units of packed red blood cells. He was previously grouped as O Rh D positive and had a history of uneventful multiple blood transfusions. His latest pre-transfusion investigations showed ABO discrepancy between forward and reverse blood grouping, pan-agglutination in both antibody screening and identification with negative direct Coombs test and autocontrol. Further testing including anti-H lectin test and saliva secretor study confirmed that the patient blood group was para-Bombay B RhD positive. This case highlights that the para-Bombay phenotype can be mistakenly labelled as "O" if further investigations are not performed.
  4. Azhar NA, Ghozali SZ, Abu Bakar SA, Lim V, Ahmad NH
    Toxicol In Vitro, 2020 Sep;67:104910.
    PMID: 32526345 DOI: 10.1016/j.tiv.2020.104910
    Application of silver nanoparticles serves as a new approach in cancer treatment due to its unique features. Biosynthesis of silver nanoparticles using plant is advantageous since they are easily accessible, nontoxic and produce quicker reaction compared to other methods. To evaluate the cytotoxicity, mechanism of cell death and DNA damage of biosynthesized Catharanthus roseus-silver nanoparticles on human liver cancer (HepG2) cells. The antiproliferative activity of Catharanthus roseus‑silver nanoparticles was measured using MTT assay. The cytotoxic effects were further evaluated by measuring nitric oxide and reactive oxygen species (ROS). The mechanism of cell death was determined by annexin-FITC/propidium iodide, mitochondrial membrane potential (MMP) and cell cycle assays. The assessment of DNA damage was evaluated using Comet assay method. The uptake of the nanoparticles were evaluated by Transmission Electron Microscopy (TEM). Catharanthus roseus‑silver nanoparticles has inhibited the proliferation of HepG2 cells in a time-dependent manner with a median IC50 value of 3.871 ± 0.18 μg/mL. The concentration of nitrite and ROS were significantly higher than control. The cell death was due to apoptosis associated with MMP loss, cell cycle arrest, and extensive DNA damage. TEM analysis indicated the presence of free nanoparticles and endosomes containing the nanoparticles. The findings show that Catharanthus roseus‑silver nanoparticles have produced cytotoxic effects on HepG2 cells and thus may have a potential to be used as an anticancer treatment, particularly for hepatocellular carcinoma.
  5. Zhou X, Li Y, Wang W, Wang S, Hou J, Zhang A, et al.
    Theranostics, 2020;10(21):9443-9457.
    PMID: 32863938 DOI: 10.7150/thno.46078
    Objective: Esophageal squamous cell carcinoma (ESCC) is one of the most commonly diagnosed cancer types in China. Recent genomic sequencing analysis indicated the over-activation of Hippo/YAP signaling might play important roles for the carcinogenic process and progression for ESCC patients. However, little is known about the molecular mechanisms that controls Hippo signaling activity in ESCC. Our previous studies indicated that PLCE1-an important risk factor for ESCC-linked to ESCC progression through snail signaling, during this period, we found PARK2 was an important downstream target of PLCE1-snail axis. PARK2 was decreased in ESCC human samples, and correlated with good prognosis in ESCC patients. Further research showed that PARK2 could inhibit YAP, which functions as key downstream effectors of the Hippo pathway. Here, we aim to reveal the molecular mechanisms of PARK2 modulated Hippo pathway in ESCC. Methods: To evaluate the function of PARK2 in ESCC, we used a tissue microarray (TMA) of 223 human ESCC patients and immunohistochemistry to analyze the correlation between PARK2 expression and clinicopathologic variables. Depletion of endogenous PARK2 and YAP from ESCC cells using CRISPR/Cas9 technologies. Flow cytometry and EdU cell proliferation assay were used to detect proliferation of ESCC cells. Nude mice subcutaneous injection and Ki-67 staining were used to evaluate tumor growth in vivo. Migration and invasion assays were performed. In addition, lung metastasis models in mice were used to validate the function of PARK2 in vivo. Identification of PARK2 involved in hippo pathway was achieved by expression microarray screening, double immunofluorescence staining and co-immunoprecipitation assays. The RNA-seq analysis results were validated through quantitative real-time PCR (qRT-PCR) analysis. The protein half-life of YAP was analyzed by Cycloheximide assay, and the TEAD activity was detected by Luciferase reporter assays. Results: Clinical sample of ESCC revealed that low PARK2 expression correlated with late tumor stage (P < 0.001), poor differentiation (P < 0.04), lymph node (P < 0.001) and distant metastasis (P = 0.0087). Multivariate Cox proportional regression analysis further revealed that PARK2 expression (P = 0.032) is an independent prognostic factor for the overall survival of ESCC patients. Besides, the immunohistochemistry results showed that PARK2 negatively correlated with YAP protein level (P < 0.001). PARK2 depletion promotes ESCC progression both through Hippo/YAP axis, while PARK2 overexpression suppresses ESCC tumor progression by Hippo signaling. Co-IP and ubiquitination assays revealed that PARK2 could interact with YAP in the cytosol and promotes YAP K48-linked ubiquitination at K90 sites. Conclusion: Clinical sample analysis and mechanistic study have validated PARK2 as a tumor suppressor for ESCC. Multivariate Cox proportional regression analysis further revealed that PARK2 is an independent prognostic factor for the overall survival of ESCC patients. Cellular and molecular mechanisms in this study showed that PARK2 associated with YAP protein in the cytosol, promoted YAP ubiquitination and proteasome-dependent degradation in ESCC cells. Therefore, as a novel modulator for Hippo signaling, modulation of PARK2 activity or gene expression level could be an appealing strategy to treat esophageal.
  6. Iqhbal KM, Ahmad NH
    Med J Malaysia, 2020 09;75(5):585-586.
    PMID: 32918431
    No abstract provided.
  7. Zahari NH, Abd Hamid IJ, Tuan Din SA, Hashim IF, Zainudeen ZT, Mohd Shariff N, et al.
    Malays J Med Sci, 2023 Jun;30(3):112-121.
    PMID: 37425378 DOI: 10.21315/mjms2023.30.3.10
    BACKGROUND: Intravenous immunoglobulin (IVIG) replacement therapy is increasingly in demand. This study focused on the characteristics of IVIG usage and associated factors toward the frequency status of IVIG among patients in Hospital Kuala Lumpur.

    METHODS: A retrospective cross-sectional study was performed on patients who received IVIG in Hospital Kuala Lumpur. Data were extracted from the request forms for IVIG recorded in the Pharmacy Department from January 2018 until December 2019. Chi-squared test and t-test analysis were used for statistical analysis, and a P-value of < 0.05 was considered significant.

    RESULTS: A total of 482 patients received IVIG in Hospital Kuala Lumpur. There were 243 (50.4%) females and 228 (47.3%) males with median age of the patients was 27 years old. The highest indications for IVIG among all patients were hypogammaglobulinemia and other deficiency states in 127 patients (26.3%). The most common indication for one-off treatment in adults was hypogammaglobulinemia and other deficiency states, 35%; whereas in paediatrics, it was Kawasaki disease, 20.3%. The highest indication for regular therapy among adult patients was chronic inflammatory demyelinating polyneuropathy (23.4%), while in paediatrics it was sepsis (31.1%). The clinical category was associated with the frequency status of IVIG usage in both adult and paediatric cohorts with P = 0.004 and P = 0.017, respectively.

    CONCLUSION: There were significant differences between the indication of one-off treatment and regular therapy among adult and paediatric patients. A national guideline on the prescription of IVIG for patients is instantly needed to help clinicians in prescribing IVIG appropriately.

  8. Rahman SA, Taghizadeh SK, Ramayah T, Ahmad NH
    Springerplus, 2015;4:810.
    PMID: 26722630 DOI: 10.1186/s40064-015-1580-8
    Service innovation management practice is currently being widely scrutinized mainly in the developed countries, where it has been initiated. The current study attempts to propose a framework and empirically validate and explain the service innovation practices for successful performance in the telecommunications industry of two developing countries, Malaysia and Bangladesh. The research framework proposes relationships among organisational culture, operating core (innovation process, cross-functional organisation, and implementation of tools/technology), competition-informed pricing, and performance. A total of 176 usable data from both countries are analysed for the purpose of the research. The findings show that organisational culture tends to be more influential on innovation process and cross-functional organisation in Malaysian telecommunication industry. In contrast, implementation of tools/technology plays a more instrumental role in competition-informed pricing practices in Bangladesh. This study revealed few differences in the innovation management practices between two developing countries. The findings have strategic implications for the service sectors in both the developing countries regarding implementation of innovative enterprises, especially in Bangladesh where innovation is the basis for survival. Testing the innovation management practices in the developing countries perhaps contains uniqueness in the field of innovation management.
  9. Mat Yusuf SNA, Che Mood CNA, Ahmad NH, Sandai D, Lee CK, Lim V
    R Soc Open Sci, 2020 Jul;7(7):200065.
    PMID: 32874618 DOI: 10.1098/rsos.200065
    Background: Silver nanoparticles (AgNPs) are widely used in food industries, biomedical, dentistry, catalysis, diagnostic biological probes and sensors. The use of plant extract for AgNPs synthesis eliminates the process of maintaining cell culture and the process could be scaled up under a non-aseptic environment. The purpose of this study is to determine the classes of phytochemicals, to biosynthesize and characterize the AgNPs using Clinacanthus nutans leaf and stem extracts. In this study, AgNPs were synthesized from the aqueous extracts of C. nutans leaves and stems through a non-toxic, cost-effective and eco-friendly method. Results: The formation of AgNPs was confirmed by UV-Vis spectroscopy, and the size of AgNP-L (leaf) and AgNP-S (stem) were 114.7 and 129.9 nm, respectively. Transmission electron microscopy (TEM) analysis showed spherical nanoparticles with AgNP-L and AgNP-S ranging from 10 to 300 nm and 10 to 180 nm, with average of 101.18 and 75.38 nm, respectively. The zeta potentials of AgNP-L and AgNP-S were recorded at -42.8 and -43.9 mV. X-ray diffraction analysis matched the face-centred cubic structure of silver and was capped with bioactive compounds. Fourier transform infrared spectrophotometer analysis revealed the presence of few functional groups of phenolic and flavonoid compounds. These functional groups act as reducing agents in AgNPs synthesis. Conclusion: These results showed that the biogenically synthesized nanoparticles reduced silver ions to silver nanoparticles in aqueous condition and the AgNPs formed were stable and less toxic.
  10. Zhou X, Yan Z, Hou J, Zhang L, Chen Z, Gao C, et al.
    Oncogene, 2024 Feb;43(7):495-510.
    PMID: 38168654 DOI: 10.1038/s41388-023-02923-z
    Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies in the world with poor prognosis. Despite the promising applications of immunotherapy, the objective response rate is still unsatisfactory. We have previously shown that Hippo/YAP signaling acts as a powerful tumor promoter in ESCC. However, whether Hippo/YAP signaling is involved in tumor immune escape in ESCC remains largely unknown. Here, we show that YAP directly activates transcription of the "don't eat me" signal CD24, and plays a crucial role in driving tumor cells to avoid phagocytosis by macrophages. Mechanistically, YAP regulates CD24 expression by interacting with TEAD and binding the CD24 promoter to initiate transcription, which facilitates tumor cell escape from macrophage-mediated immune attack. Our animal model data and clinical data show that YAP combined with CD24 in tumor microenvironment redefines the impact of TAMs on the prognosis of ESCC patients which will provide a valuable basis for precision medicine. Moreover, treatment with YAP inhibitor altered the distribution of macrophages and suppressed tumorigenesis and progression of ESCC in vivo. Together, our study provides a novel link between Hippo/YAP signaling and macrophage-mediated immune escape, which suggests that the Hippo-YAP-CD24 axis may act as a promising target to improve the prognosis of ESCC patients. A proposed model for the regulatory mechanism of Hippo-YAP-CD24-signaling axis in the tumor-associated macrophages mediated immune escape.
  11. Pei TP, Ahmad NH, Noor NHM
    Oman Med J, 2022 Jan;37(1):e336.
    PMID: 35136665 DOI: 10.5001/omj.2021.45
    Para-Bombay blood phenotype is a rare blood group with limited cases reported worldwide. This blood group is characterized by the absence of ABH antigen on red blood cells but presence of ABH secretor substances in the body secretion. This rare phenotype is usually misinterpreted as O and may endanger the patient if urgent blood transfusion is required. A mother who was labelled as group O Rh D positive during antenatal follow-up was found to have ABO discrepancy during delivery. The newborn was admitted for extremely premature delivery at 25 weeks. As the baby required transfusion, problem arose during cross matching with the mother's sample. It was found that the mother was group O Rh D positive in forward grouping. However, the reverse grouping showed the presence of reaction (2+) in O cells. The baby was grouped as O Rh D positive. As transfusion was urgently needed due to baby's unstable condition, group O Rh D positive packed cell was found compatible with baby's serum, subsequently transfused. Bombay blood donor was contacted, and the donated blood was sent to the hospital for further management. Further investigations were performed, indicating that the mother is para-Bombay A. Due to recent transfusion to baby, we suggested to repeat baby's blood group after the baby is one year old. Para-Bombay was usually mislabelled as O if the sample was not tested with O cell in reverse grouping. Additional tests may be needed during antenatal follow-up to prevent complications during delivery, which requires emergency blood transfusion.
  12. Ng EP, Ahmad NH, Khoerunnisa F, Mintova S, Ling TC, Daou TJ
    Molecules, 2021 Apr 13;26(8).
    PMID: 33924655 DOI: 10.3390/molecules26082238
    Offretite zeolite synthesis in the presence of cetyltrimethylammonium bromide (CTABr) is reported. The offretite crystals were synthesized with a high crystallinity and hexagonal prismatic shape after only 72 h of hydrothermal treatment at 180 °C. The CTABr has dual-functions during the crystallization of offretite, viz. as structure-directing agent and as mesoporogen. The resulting offretite crystals, with a Si/Al ratio of 4.1, possess more acid sites than the conventional offretite due to their high crystallinity and hierarchical structure. The synthesized offretite is also more reactive than its conventional counterpart in the acylation of 2-methylfuran for biofuel production under non-microwave instant heating condition, giving 83.5% conversion with 100% selectivity to the desired product 2-acetyl-5-methylfuran. Hence, this amphiphile synthesis approach offers another cost-effective and alternative route for crystallizing zeolite materials that require expensive organic templates.
  13. Chan HY, Meor Hussin AS, Ahmad NH, Rukayadi Y, Farouk AE
    Molecules, 2021 Aug 30;26(17).
    PMID: 34500692 DOI: 10.3390/molecules26175259
    Table eggs are an affordable yet nutritious protein source for humans. Unfortunately, eggs are a vector for bacteria that could cause foodborne illness. This study aimed to investigate the effectiveness of a quaternary ammonium compound (quat) sanitizer against aerobic mesophilic bacteria, yeast, and mold load on the eggshell surface of free-range and commercial farms and the post-treatment effect on microbial load during storage. Total aerobic mesophilic bacteria, yeast, and molds were enumerated using plate count techniques. The efficacy of the quaternary ammonium sanitizer (quat) was tested using two levels: full factorial with two replicates for corner points, factor A (maximum: 200 ppm, minimum: 100 ppm) and factor B (maximum: 15 min, minimum: 5 min). Quat sanitizer significantly (p < 0.05) reduced approximately 4 log10 CFU/cm2 of the aerobic mesophilic bacteria, 1.5 to 2.5 log10 CFU/cm2 of the mold population, and 1.5 to 2 log10 CFU/cm2 of the yeast population. However, there was no significant (p ≥ 0.05) response observed between individual factor levels (maximum and minimum), and two-way interaction terms were also not statistically significant (p ≥ 0.05). A low (<1 log10 CFU/cm2) aerobic mesophilic bacteria trend was observed when shell eggs were stored in a cold environment up to the production expiry date. No internal microbial load was observed; thus, it was postulated that washing with quat sanitizer discreetly (without physically damaging the eggshell) does not facilitate microbial penetration during storage at either room temperature or cold storage. Current study findings demonstrated that the quat sanitizer effectively reduced the microbial population on eggshells without promoting internal microbial growth.
  14. Tan PP, Mohamed Fauzi, H., Chang CT, Ahmad NH, Bahar B, Mangantig E, et al.
    MyJurnal
    ABSTRACTS FOR INTERNATIONAL HEALTH AND MEDICAL SCIENCES CONFERENCE 2019 (IHMSC 2019)
    Held at Taylor’s University Lakeside Campus, Subang Jaya, Selangor, Malaysia, 8-9th March, 2019
    Introduction: Unsafe blood products cause transfusion-transmissible infections among blood receivers. The knowledge and perception of blood donors is important as it is associated with their donation behaviour and hence the safety of blood products. There was no previous study that assessed the knowledge and perception on blood safety issues among blood donors to date. The objective of this study was to assess the knowledge and perception of blood
    donors on blood safety issues.
    Methods: This was a pilot study conducted to pilot test the self-developed questionnaire by the researchers. The questionnaire was available in the Malay language. One-hundred-thirty donors at the National Blood Centre were recruited to complete the self-administered questionnaire. Health sciences professionals, medical students and non-Malaysians were excluded in this study.
    Results: A total of 130 donors comprising of 70 males (53.8%) and 60 females (46.2%) responded. The mean age of the respondents is 32.48±8.86 years. Most of the respondents were Malay (55.4%), single (49.2%), working in private sector (46.9%) and regular donor (68.5%). More than half of the respondents did not know that dengue, Zika and mad-cow disease can be contracted through blood transfusion. Ten percent of the respondents answered that bisexual people are eligible to donate blood. 40.7% of the donors agreed to check their HIV status through blood donation. Majority of the donors (60.7%) agreed that the donors’ blood is safe if the screening test is negative. Whereas, 33.9% of the donors disagreed that they shall be responsible if their blood causes infection.
    Conclusion: Several knowledge gaps and inappropriate perception among the respondents were identified and these might affect the safety of the blood products. Targeted measures should be taken to rectify donors’ knowledge and perception in order to minimise inappropriate blood donor behaviours and reduce unsafe blood products.
  15. Oslan SNH, Yusof NY, Lim SJ, Ahmad NH
    J Microbiol Methods, 2024 Apr;219:106897.
    PMID: 38342249 DOI: 10.1016/j.mimet.2024.106897
    Salmonella is as an intracellular bacterium, causing many human fatalities when the host-specific serotypes reach the host gastrointestinal tract. Nontyphoidal Salmonella are responsible for numerous foodborne outbreaks and product recalls worldwide whereas typhoidal Salmonella are responsible for Typhoid fever cases in developing countries. Yet, Salmonella-related foodborne disease outbreaks through its food and water contaminations have urged the advancement of rapid and sensitive Salmonella-detecting methods for public health protection. While conventional detection methods are time-consuming and ineffective for monitoring foodstuffs with short shelf lives, advances in microbiology, molecular biology and biosensor methods have hastened the detection. Here, the review discusses Salmonella pathogenic mechanisms and its detection technology advancements (fundamental concepts, features, implementations, efficiency, benefits, limitations and prospects). The time-efficiency of each rapid test method is discussed in relation to their limit of detections (LODs) and time required from sample enrichment to final data analysis. Importantly, the matrix effects (LODs and sample enrichments) were compared within the methods to potentially speculate Salmonella detection from environmental, clinical or food matrices using certain techniques. Although biotechnological advancements have led to various time-efficient Salmonella-detecting techniques, one should consider the usage of sophisticated equipment to run the analysis by moderately to highly trained personnel. Ultimately, a fast, accurate Salmonella screening that is readily executed by untrained personnels from various matrices, is desired for public health procurement.
  16. Mohammed NK, Ahmad NH, Muhialdin BJ, Meor Hussin AS
    J Food Sci Technol, 2024 Mar;61(3):528-538.
    PMID: 38327854 DOI: 10.1007/s13197-023-05860-7
    This work aims to produce a virgin coconut oil (VCO) creamer through two drying stages; spray drying followed by fluidised bed drying, and to examine its antioxidant properties and oxidative stability during different storage conditions. Evaluation of the physicochemical properties of spray dry VCO and oxidative stability of the VCO creamer were performed using peroxide value (PV), antioxidant activity (DPPH), and total phenolic content (TPC) at 25, 4, and 25 °C, respectively, for 8 weeks. Agglomeration process has improved the agglomerated VCO creamer's properties in terms of moisture content (4.34%), solubility (85.2%), water activity (0.32%), and bulk density (0.36 g/cm3). The morphology of agglomerated VCO creamer showed cluster and irregular shapes with enlargement in the particle size, (d32) 395 µm and (d43) 426 µm. The overall oxidative results showed stability for the agglomerated VCO creamer stored at 4 °C in terms of TPC, DPPH and PV over 8 weeks followed by creamer stored at 25 °C which had similar stability with slight differences. The creamer stored at 38 °C showed rapid degradation for all oxidation tests from week 2 onwards. Agglomeration technology has indicated to be effective in the stabilization of virgin coconut oil against lipid oxidation and prolonging its shelf-life.
  17. Ahmad NH, Ahmed J, Hashim DM, Manap YA, Mustafa S
    J Food Sci Technol, 2015 May;52(5):2902-9.
    PMID: 25892789 DOI: 10.1007/s13197-014-1330-x
    Oscillatory and steady shear rheology of gellan (G) and dextran (D) solution individually, and in blends (G/D ratio 1:1, 1:2, and 1:3 w/v) with a total hydrocolloid concentration of 3 % (w/v) were studied at 25 °C. Individually, 1.5 % dextran and 1.5 % gellan in solution exhibited Newtonian and non-Newtonian behavior, respectively. A blend of equal proportion of dextran and gellan (G/D = 1:1) exhibits a distinct gel point (G' = G″), and further addition of dextran in the blend (G/D = 1:2 and 1:3) resulted predominating liquid-like (G″ > G') behavior. A plot of G' vs G″ distinctly showed the gradual transition of the blend. Shear stress (τ)-shear rate ([Formula: see text]) data fitted well the Herschel-Bulkley model. The G/D blend exhibited shear thinning behavior with flow behavior index less than unity. The Cox-Merz rule did not fit well for the complex shear viscosity (η*) and apparent viscosity (η) of the blend.
  18. Abdul Rahim R, Jayusman PA, Muhammad N, Mohamed N, Lim V, Ahmad NH, et al.
    PMID: 33805420 DOI: 10.3390/ijerph18073532
    Oxidative stress and inflammation are two common risk factors of various life-threatening disease pathogenesis. In recent years, medicinal plants that possess antioxidant and anti-inflammatory activities were extensively studied for their potential role in treating and preventing diseases. Spilanthes acmella (S. acmella), which has been traditionally used to treat toothache in Malaysia, contains various active metabolites responsible for its anti-inflammatory, antiseptic, and anesthetic bioactivities. These bioactivities were attributed to bioactive compounds, such as phenolic, flavonoids, and alkamides. The review focused on the summarization of in vitro and in vivo experimental reports on the antioxidant and anti-inflammatory actions of S. acmella, as well as how they contributed to potential health benefits in lowering the risk of diseases that were related to oxidative stress. The molecular mechanism of S. acmella in reducing oxidative stress and inflammatory targets, such as inducible nitric oxide synthase (iNOS), transcription factors of the nuclear factor-κB family (NF-κB), cyclooxygenase-2 (COX-2), and mitogen-activated protein kinase (MAPK) signaling pathways were discussed. Besides, the antioxidant potential of S. acmella was measured by total phenolic content (TPC), total flavonid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide anion radical scavenging (SOD) and thiobarbituric acid reactive substance (TBARS) assays. This review revealed that S. acmella might have a potential role as a reservoir of bioactive agents contributing to the observed antioxidant, anti-inflammatory, and health beneficial effects.
  19. Othman NE, Zaki SA, Rijal HB, Ahmad NH, Razak AA
    Int J Biometeorol, 2021 Apr;65(4):453-477.
    PMID: 33416948 DOI: 10.1007/s00484-020-02035-3
    Difficulties in controlling the effects of outdoor thermal environment on the human body are attracting considerable research attention. This study investigated the outdoor thermal comfort of urban pedestrians by assessing their perceptions of the tropical, micrometeorological, and physical conditions via a questionnaire survey. Evaluation of the outdoor thermal comfort involved pedestrians performing various physical activities (sitting, walking, and standing) in outdoor and semi-outdoor spaces where the data collection of air temperature, globe temperature, relative humidity, wind speed, solar radiation, metabolic activity, and clothing insulation data was done simultaneously. A total of 1011 participants were interviewed, and the micrometeorological data were recorded under outdoor and semi-outdoor conditions at two Malaysian university campuses. The neutral temperatures obtained which were 28.1 °C and 30.8 °C were within the biothermal acceptable ranges of 24-34 °C and 26-33 °C of the PET thermal sensation ranges for the outdoor and semi-outdoor conditions, respectively. Additionally, the participants' thermal sensation and preference votes were highly correlated with the PET and strongly related to air and mean radiant temperatures. The findings demonstrated the influence of individuals' thermal adaptation on the outdoor thermal comfort levels. This knowledge could be useful in the planning and designing of outdoor environments in hot and humid regions to create better thermal environments.
  20. Krishnamoorthy M, Ahmad NH, Amran HN, Mohamed MA, Kaus NHM, Yusoff SFM
    Int J Biol Macromol, 2021 Jul 01;182:1495-1506.
    PMID: 34019924 DOI: 10.1016/j.ijbiomac.2021.05.104
    Semiconductor materials have shown a good photocatalytic behaviour for the photodegradation of organic pollutants. In this work, maleated liquid natural rubber (MLNR) based hydrogel supported bismuth ferrite (BiFeO3) as photocatalyst was successfully synthesized by crosslinking with acrylic acid (AAc) assisted by the ultrasonication method to study the efficiency for the removal of methylene blue (MB) dye in wastewater. Response surface methodology (RSM) was used to optimize the parameters for adsorption of the methylene blue (MB) dye compound, whereby the effects of the initial concentration of MB and the adsorption time were examined to obtain a quadratic model for the respective hydrogel composite. The prepared composite sample was characterized by Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) and X-ray Diffraction (XRD) analysis. Remarkable improvement for removal of methylene blue (99% removal) was found within 3 h adsorption time with a MLNR/AAc-BiFeO3 hydrogel composite as compared to the pristine hydrogel. A synergistic mode of dye removal by adsorption and photodegradation is proposed. Based on the isotherm and kinetic study conducted, it was found that Freundlich isotherm model and a pseudo second-order kinetic model was best fitted for adsorption of MB dye. The MLNR/AAc-BiFeO3 composite maintains its removal efficiency after 5 cycles without the necessity of post-treatment separation. Therefore, it is crucial to note that the resultant low-cost MLNR/AAc-BiFeO3 hydrogel composite in this study offers excellent potential for water and wastewater treatment applications with improved recyclability and recovery.
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