Displaying publications 81 - 100 of 339 in total

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  1. Fulltext Morphological Variability Identification of Harumanis Mango (Mangifera indica L.) Harvested from Different Location and Tree Age
    Yusuf SNA, Rahman AMA, Zakaria Z, Subbiah VK, Masnan MJ, Wahab Z
    Trop Life Sci Res, 2020 Jul;31(2):107-143.
    PMID: 32922671 DOI: 10.21315/tlsr2020.31.2.6
    Harumanis is one of the main signatures of Perlis with regards to its delightful taste, pleasant aroma and expensive price. Harumanis authenticity and productivity had become the remarks among the farmers, entrepreneurs, consumers and plant breeders due to the existence of morphological characteristics variation among the fruits and high production cost. Assessment of Harumanis morphological characteristics of natural population and different tree ages may represent a possible source of important characteristics for development and breeding purposes of Harumanis. The aim of this study is to evaluate the morphological variation of Harumanis collected from different location in Perlis and tree age. A total of 150 Harumanis fruits from 50 trees with three different stages of development (young, middle-aged and old) were characterised using 11 traits; 10 quantitative and one qualitative morphological trait. The ANOVA analyses in combination with Dunn's pairwise and Kruskal-Wallis multiple comparison test able to point out the existence of environmental factor and age influence towards the significant different of identified morphological traits except for Total Soluble Solid (TSS) and pulp percentage. Five clusters of 50 Harumanis accessions reflect a grouping pattern which not according to neither geographical region nor age. The result of Principal Component Analysis (PCA) using the first two principal components (PCs) provided a good approximation of the data explaining 84.09% of the total variance which majorly contributed by parameters of weight, fruit dimensional characteristics, peel percentage and hue angle, h. Preliminary screening of important morphological characteristics which contribute to the phenotypic diversity of Harumanis is successfully achieved. The findings can be employed by the plant breeders and farmers for the establishment of standard grading of Harumanis and advancement of breeding crop of Harumanis in future.
  2. Enzymatic esterification of eugenol and benzoic acid by a novel chitosan-chitin nanowhiskers supported Rhizomucor miehei lipase: Process optimization and kinetic assessments
    Manan FMA, Attan N, Zakaria Z, Keyon ASA, Wahab RA
    Enzyme Microb Technol, 2018 Jan;108:42-52.
    PMID: 29108626 DOI: 10.1016/j.enzmictec.2017.09.004
    A biotechnological route via enzymatic esterification was proposed as an alternative way to synthesize the problematic anti-oxidant eugenyl benzoate. The new method overcomes the well-known drawbacks of the chemical route in favor of a more sustainable reaction process. The present work reports a Box-Behnken design (BBD) optimization process to synthesize eugenyl benzoate by esterification of eugenol and benzoic acid catalyzed by the chitosan-chitin nanowhiskers supported Rhizomucor miehei lipase (RML-CS/CNWs). Effects of four reaction parameters: reaction time, temperature, substrate molar ratio of eugenol: benzoic acid and enzyme loading were assessed. Under optimum conditions, a maximum conversion yield as high as 66% at 50°C in 5h using 3mg/mL of RML-CS/CNWs, and a substrate molar ratio (eugenol: benzoic acid) of 3:1. Kinetic assessments revealed the RML-CS/CNWs catalyzed the reaction via a ping-pong bi-bi mechanism with eugenol inhibition, characterized by a Vmax of 3.83mMmin-1. The Michaelis-Menten constants for benzoic acid (Km,A) and eugenol (Km,B) were 34.04 and 138.28mM, respectively. The inhibition constant for eugenol (Ki,B) was 438.6mM while the turnover number (kcat) for the RML-CS/CNWs-catalyzed esterification reaction was 40.39min-1. RML-CS/CNWs were reusable up to 8 esterification cycles and showed higher thermal stability than free RML.
  3. Tuberculosis in captive Asian elephants (Elephas maximus) in Peninsular Malaysia
    Ong BL, Ngeow YF, Razak MF, Yakubu Y, Zakaria Z, Mutalib AR, et al.
    Epidemiol Infect, 2013 Jul;141(7):1481-7.
    PMID: 23414617 DOI: 10.1017/S0950268813000265
    A cross-sectional study was conducted from 10 January to 9 April 2012, to determine the seroprevalence of tuberculosis (TB) of all captive Asian elephants and their handlers in six locations in Peninsular Malaysia. In addition, trunk-wash samples were examined for tubercle bacillus by culture and polymerase chain reaction (PCR). For 63 elephants and 149 elephant handlers, TB seroprevalence was estimated at 20.4% and 24.8%, respectively. From 151 trunkwash samples, 24 acid-fast isolates were obtained, 23 of which were identified by hsp65-based sequencing as non-tuberculous mycobacteria. The Mycobacterium tuberculosis-specific PCR was positive in the trunk-wash samples from three elephants which were also seropositive. Conversely, the trunk wash from seven seropositive elephants were PCR negative. Hence, there was evidence of active and latent TB in the elephants and the high seroprevalence in the elephants and their handlers suggests frequent, close contact, two-way transmission between animals and humans within confined workplaces.
  4. Fulltext Methanol extract of Bauhinia purpurea leaf possesses anti-ulcer activity
    Zakaria ZA, Abdul Hisam EE, Norhafizah M, Rofiee MS, Othman F, Hasiah AH, et al.
    Med Princ Pract, 2012;21(5):476-82.
    PMID: 22398984 DOI: 10.1159/000336593
    The aim of the present study was to determine the anti-ulcer activity of a methanol extract of Bauhinia purpurea leaf (MEBP).
  5. Application of multiplex PCR for characterization of human embryonic stem cells (hESCs) and its differentiated progenies
    Mamidi MK, Pal R, Bhonde R, Zakaria Z, Totey S
    J Biomol Screen, 2010 Jul;15(6):630-43.
    PMID: 20530724 DOI: 10.1177/1087057110370211
    Techniques to evaluate gene expression profiling, including real-time quantitative PCR, TaqMan low-density arrays, and sufficiently sensitive cDNA microarrays, are efficient methods for monitoring human embryonic stem cell (hESC) cultures. However, most of these high-throughput tests have a limited use due to high cost, extended turnaround time, and the involvement of highly specialized technical expertise. Hence, there is a paucity of rapid, cost-effective, robust, yet sensitive methods for routine screening of hESCs. A critical requirement in hESC cultures is to maintain a uniform undifferentiated state and to determine their differentiation capacity by showing the expression of gene markers representing all germ layers, including ecto-, meso-, and endoderm. To quantify the modulation of gene expression in hESCs during their propagation, expansion, and differentiation via embryoid body (EB) formation, the authors developed a simple, rapid, inexpensive, and definitive multimarker, semiquantitative multiplex RT-PCR (mxPCR) platform technology. Among the 15 gene primers tested, 4 were pluripotent markers comprising set 1, and 3 lineage-specific markers from each ecto-, meso-, and endoderm layers were combined as sets 2 to 4, respectively. The authors found that these 4 sets were not only effective in determining the relative differentiation in hESCs, but were easily reproducible. In this study, they used the HUES-7 cell line to standardize the technique, which was subsequently validated with HUES-9, NTERA-2, and mouse embryonic fibroblast cells. This single-reaction mxPCR assay was flexible and, by selecting appropriate reporter genes, can be designed for characterization of different hESC lines during routine maintenance and directed differentiation.
  6. Fulltext Influence of Graphene Oxide on the Ethanol Permeability and Ionic Conductivity of QPVA-Based Membrane in Passive Alkaline Direct Ethanol Fuel Cells
    Zakaria Z, Kamarudin SK, Timmiati SN
    Nanoscale Res Lett, 2019 Jan 18;14(1):28.
    PMID: 30659414 DOI: 10.1186/s11671-018-2836-3
    Passive alkaline-direct ethanol fuel cells (alkaline-DEFCs) appear to be suitable for producing sustainable energy for portable devices. However, ethanol crossover is a major challenge for passive alkaline-DEFC systems. This study investigated the performance of a crosslinked quaternized poly (vinyl alcohol)/graphene oxide (QPVA/GO) composite membrane to reduce ethanol permeability, leading in enhancement of passive alkaline-DEFC performance. The chemical and physical structure, morphology, ethanol uptake and permeability, ion exchange capacity, water uptake, and ionic conductivity of the composite membranes were characterized and measured to evaluate their applicability in fuel cells. The transport properties of the membrane were affected by GO loading, with an optimal loading of 15 wt.% and doped with 1 M of KOH showing the lowest ethanol permeability (1.49 × 10-7 cm2 s-1 and 3.65 × 10-7 cm2 s-1 at 30 °C and 60 °C, respectively) and the highest ionic conductivity (1.74 × 10-2 S cm-1 and 6.24 × 10-2 S cm-1 at 30 °C and 60 °C, respectively). In the passive alkaline-DEFCs, the maximum power density was 9.1 mW cm-2, which is higher than commercial Nafion 117/KOH (7.68 mW cm-2) at 30 °C with a 2 M ethanol + 2 M KOH solution. For the 60 °C, the maximum power density of composite membrane achieved was 11.4 mW cm-2.
  7. Fulltext Adult allogeneic haematopoietic stem cell transplantation: a single centre experience in Malaysia
    Gan GG, Zakaria Z, Sangkar JV, Haris AR, Bee PC, Chin E, et al.
    Med J Malaysia, 2008 Oct;63(4):281-7.
    PMID: 19385485 MyJurnal
    We analysed the outcome of 104 patients from a single institution who underwent allogeneic haematopoietic stem cell transplantation (AHSCT) from their HLA-identical siblings between 1993 and 2006. Sixty-nine percent of patients had peripheral blood stem cell (PBSC) as the stem cell source and the remaining had bone marrow (BM). The majority of patients are Chinese (60%) followed by Malays (24%) and Indians (14%). The median time to reach white cell counts of >1 x 10(9)/L and platelet counts of >30 x 10(9)/L was 13 and 15 days, respectively in patients who had PBSC transplantation compared with 16 and 25 days in patients who had BM transplantation, (p < 0.0001 and p < 0.001). Acute graft-versus-host disease (aGVHD) of grade II to IV was observed in 34% of patients and chronic graft-versus-host disease (cGVHD) in 38% of patients. Although not statistically significant, there was a higher incidence of overall aGVHD in Indian patients (73%) compared to Chinese and Malays (57% and 56% respectively). There was no significant difference in the incidence of aGVHD and cGVHD with the source of stem cells. Overall survival (OS) and disease free survival (DFS) was 50% and 60% at five years respectively. Multivariate analysis showed that patients transplanted in standard risk and those who had limited cGVHD had a significant better OS, (p = 0.05 and p = 0.05). Patients who had cGVHD and transplanted in standard risk had a better DFS, (p = 0.002 and p < 0.001). In summary, AHSCT in standard risk patients is associated with a better outcome than those transplanted in high risk and although not statistically significant, there is a higher incidence of aGVHD in Indian patients.
  8. Fulltext Identification of αo-thalassaemia (–SEA) using an Enzyme- Linked Immunosorbent Assay (ELISA) for embryonic zeta-globin chain detection – a preliminary study
    Tan, J. A. M. A., George, E., Lim, E. J., Zakaria, Z., Hassan, R., Wee, Y. C., et al.
    Malaysian Journal of Medicine and Health Sciences, 2006;2(2):81-87.
    MyJurnal
    Objectives: This study aimed to evaluate the UBI MAGIWELTM ζ-GLOBIN ELISA Kit for the presumptive diagnosis of αo-thalassaemia. The ELISA results obtained were confirmed by molecular characterisation of αo-thalassaemia using a Duplex-PCR. Methods: Routine peripheral blood counts and red cell indices were determined in 94 blood samples sent for Hb analysis. Hb subtypes were quantified by high performance liquid chromatography (HPLC) and Hb electrophoresis conducted on agarose gel at pH 8.5. Zeta-globin chain levels were determined using the UBI MAGIWELTM ζ-GLOBIN ELISA Kit. Molecular analysis was performed using a duplex-PCR which simultaneously amplifies
    a normal 136 bp sequence between the ψα−α2-globin genes and a 730 bp Southeast Asian deletion-specific sequence (–SEA) between the ψα2−θ1-globin genes. Results: Using the ELISA assay kit, 20 blood samples were presumptively identified as α-thalassaemia carriers from elevated ζ-globin chains (OD>0.3) while the remaining 74 blood samples showed OD
  9. Fulltext Expression and mutational analysis of GATA3 in Malaysian breast carcinomas
    Bong PN, Zakaria Z, Muhammad R, Abdullah N, Ibrahim N, Emran NA, et al.
    Malays J Pathol, 2010 Dec;32(2):117-22.
    PMID: 21329183 MyJurnal
    The GATA3 gene is a potential tumour marker and putative tumour suppressor gene in breast cancer. Its expression is associated with better prognosis and disease free survival in breast cancer patients. We aimed to evaluate GATA3 transcriptome expression and mutation in breast carcinomas and correlate its expression with oestrogen receptor (ER), progesterone receptor (PR), lymph node (LN) status, tumour grade and c-erbB-2 expression. Twenty-two breast infiltrating ductal carcinomas and paired normal tissues were used in Branch DNA assay to detect GATA3 mRNA expression. Normalized data for GATA3 mRNA expression were grouped according to the ER, PR and LN status, tumour grade and c-erbB-2 expression of the tumours. Statistical significance was tested using t-test and ANOVA at 95% confidence interval level. Mutational analysis of GATA3 was performed by direct sequencing of the coding regions of GATA3 mRNA. Our findings showed that GATA3 gene were over-expressed and under-expressed by > 2 fold change in 12 and 4 tested samples, respectively. Eighty per cent of ER positive breast carcinomas were GATA3 positive. There was a statistically significant correlation between GATA3 expression and ER at 95% confidence interval level between the study groups. On the contrary, GATA3 expression was not statistically significant with PR, LN, tumour grade and c-erbB-2 expression in our study. In addition, we observed that there was no mutation in mRNA coding region in 16 breast carcinomas that showed GATA3 differential gene expression. Our preliminary results suggested that GATA3 is linked to the ER. This scenario suggests that GATA3 may play a crucial role in oestrogen receptor positive breast cancer patients. Whether GATA3 expression is involved in regulating tumour cell growth in oestrogen responsive breast cancer is a key question that remains to be answered.
  10. Fulltext Gene expression patterns distinguish breast carcinomas from normal breast tissues: the Malaysian context
    Pau Ni IB, Zakaria Z, Muhammad R, Abdullah N, Ibrahim N, Aina Emran N, et al.
    Pathol Res Pract, 2010 Apr 15;206(4):223-8.
    PMID: 20097481 DOI: 10.1016/j.prp.2009.11.006
    Genomic and transcriptomic alterations that affect cellular processes, such as cell proliferation, differentiation, apoptosis and invasion, commonly occur in breast oncogenesis. Epidemiological evidence has proven that the risk of breast cancer predisposition varies among different ethnicities. This study aims to identify the transcriptome changes that commonly occur during the transition of normal breast epithelium to carcinoma in three local ethnic groups (Malays, Chinese and Indians). The gene expression patterns of 43 breast carcinomas with 43 patient-matched normal breast tissues were investigated using Affymetrix U133A GeneChip (containing 22,283 probe sets targeting approximately 18,400 different transcripts) and analyzed with GeneSpring GX10. Our findings revealed a total of 33 significantly differentially expressed genes, which showed>2-fold change at a 99.9% confidence interval level (p<0.001). The significantly differentially expressed genes included CD24, CD36, CD9, TACSTD1, TACSTD2, HBB, LEP, LPL, AKR1C1, AKR1C2 and AKR1C3. Our results indicate that the vast majority of gene expression changes, from normal breast epithelial to carcinoma, found in our three major ethnic populations are similar to those in the Caucasian population. Further study of the differentially expressed genes identified in our present study is needed to search for potential breast tumor biomarkers. This will eventually help to improve the therapeutic and treatment strategies for breast cancer patients in the future.
  11. Fulltext Epidermal growth factor receptor (EGFR) gene alteration and protein overexpression in Malaysian triple-negative breast cancer (TNBC) cohort
    Zakaria Z, Zulkifle MF, Wan Hasan WAN, Azhari AK, Abdul Raub SH, Eswaran J, et al.
    Onco Targets Ther, 2019;12:7749-7756.
    PMID: 31571924 DOI: 10.2147/OTT.S214611
    Background: Epidermal growth factor receptor (EGFR) is a member of the ErbB family of tyrosine kinase receptor proteins that plays important roles in tumour cell survival and proliferation. EGFR has been reported to be overexpressed in up to 78% of triple-negative breast cancer (TNBC) cases suggesting it as a potential therapeutic target. The clinical trials of anti-EGFR agents in breast cancer showed low response rates. However, a subgroup of patients demonstrated response to EGFR inhibitors highlighting the necessity to stratify patients, who might benefit from effective combination therapy that could include anti EGFR-agents. Population variability in EGFR expression warrants systematic evaluation in specific populations.

    Purpose: To study EGFR alterations and expressions in a multi ethnic Malaysian TNBC patient cohort to determine the possibility of using anti-EGFR combinatorial therapy for this population.

    Patients and methods: In this study, we evaluated 58 cases of Malaysian TNBC patient samples for EGFR gene copy number alteration and EGFR protein overexpression using fluorescence in-situ hybridization (FISH) and immunohistochemistry (IHC) methods, respectively.

    Results: EGFR protein overexpression was observed in about 30% while 15.5% displayed high EGFR copy number including 5.17% gene amplification and over 10% high polysomy. There is a positive correlation between EGFR protein overexpression and gene copy number and over expression of EGFR is observed in ten out of the 48 low copy number cases (20.9%) without gene amplification.

    Conclusion: This study provides the first glimpse of EGFR alterations and expressions in a multi ethnic Malaysian TNBC patient cohort emphasising the need for the nationwide large scale EGFR expression evaluation in Malaysia.

  12. Distribution of HPV genotypes in cervical cancer in multi- ethnic Malaysia
    Hamzi Abdul Raub S, Isa NM, Zailani HA, Omar B, Abdullah MF, Mohd Amin WA, et al.
    Asian Pac J Cancer Prev, 2014;15(2):651-6.
    PMID: 24568473
    BACKGROUND: Cervical cancer is the third commonest type of cancer among women in Malaysia. Our aim was to determine the distribution of human papilloma virus (HPV) genotypes in cervical cancer in our multi-ethnic population.

    MATERIALS AND METHODS: This was a multicentre study with a total of 280 cases of cervical cancer from 4 referral centres in Malaysia, studied using real-time polymerase chain reaction (qPCR) detection of 12 high risk-HPV genotypes.

    RESULTS: Overall HPV was detected in 92.5% of cases, in 95.9% of squamous cell carcinomas and 84.3%of adenocarcinomas. The five most prevalent high-risk HPV genotypes were HPV 16 (68.2%), 18 (40%), 58 (10.7%), 33 (10.4%) and 52 (10.4%). Multiple HPV infections were more prevalent (55.7%) than single HPV infections (36.8%). The percentage of HPV positive cases in Chinese, Malays and Indians were 95.5%, 91.9% and 80.0%, respectively. HPV 16 and 18 genotypes were the commonest in all ethnic groups. We found that the percentage of HPV 16 infection was significantly higher in Chinese (75.9%) compared to Malays (63.7%) and Indians (52.0%) (p<0.05), while HPV 18 was significantly higher in Malays (52.6%) compared to Chinese (25.0%) and Indians (28%) (p<0.05). Meanwhile, HPV 33 (17.9%) and 52 (15.2%) were also more commonly detected in the Chinese (p<0.05).

    CONCLUSIONS: This study showed that the distribution of HPV genotype in Malaysia is similar to other Asian countries. Importantly, we found that different ethnic groups in Malaysia have different HPV genotype infection rates, which is a point to consider during the implementation of HPV vaccination.

  13. Fluid-structure interaction (FSI) modeling of bone marrow through trabecular bone structure under compression
    Rabiatul AAR, Fatihhi SJ, Md Saad AP, Zakaria Z, Harun MN, Kadir MRA, et al.
    Biomech Model Mechanobiol, 2021 Jun;20(3):957-968.
    PMID: 33547975 DOI: 10.1007/s10237-021-01423-x
    The present study has sought to investigate the fluid characteristic and mechanical properties of trabecular bone using fluid-structure interaction (FSI) approach under different trabecular bone orientations. This method imposed on trabecular bone structure at both longitudinal and transverse orientations to identify effects on shear stress, permeability, stiffness and stress regarded to the trabeculae. Sixteen FSI models were performed on different range trabecular cubes of 27 mm3 with eight models developed for each longitudinal and transverse direction. Results show that there was a moderate correlation between permeability and porosity, and surface area in the longitudinal and transverse orientations. For the longitudinal orientation, the permeability values varied between 3.66 × 10-8 and 1.9 × 10-7 and the sheer stress values varied between 0.05 and 1.8 Pa, whilst for the transverse orientation, the permeability values varied between 5.95 × 10-10 and 1.78 × 10-8 and the shear stress values varied between 0.04 and 3.1 Pa. Here, transverse orientation limits the fluid flow from passing through the trabeculae due to high shear stress disturbance generated within the trabecular bone region. Compared to physiological loading direction (longitudinal orientation), permeability is higher within the range known to trigger a response in bone cells. Additionally, shear stresses also increase with bone surface area. This study suggests the shear stress within bone marrow in real trabecular architecture could provide the mechanical signal to marrow cells that leads to bone anabolism and can depend on trabecular orientation.
  14. Fulltext Enhancement of astaxanthin accumulation using black light in Coelastrum and Monoraphidium isolated from Malaysia
    Kaha M, Iwamoto K, Yahya NA, Suhaimi N, Sugiura N, Hara H, et al.
    Sci Rep, 2021 06 03;11(1):11708.
    PMID: 34083633 DOI: 10.1038/s41598-021-91128-z
    Microalgae are important microorganisms which produce potentially valuable compounds. Astaxanthin, a group of xanthophyll carotenoids, is one of the most powerful antioxidants mainly found in microalgae, yeasts, and crustaceans. Environmental stresses such as intense light, drought, high salinity, nutrient depletion, and high temperature can induce the accumulation of astaxanthin. Thus, this research aims to investigate the effect of black light, also known as long-wave ultraviolet radiation or UV-A, as a stressor on the accumulation of astaxanthin as well as to screen the antioxidant property in two tropical green algal strains isolated from Malaysia, Coelastrum sp. and Monoraphidium sp. SP03. Monoraphidium sp. SP03 showed a higher growth rate (0.66 day-1) compared to that of Coelastrum sp. (0.22 day-1). Coelastrum sp. showed significantly higher accumulation of astaxanthin in black light (0.999 g mL culture-1) compared to that in control condition (0.185 g mL-1). Similarly, Monoraphidium sp. SP03 showed higher astaxanthin content in black light (0.476 g mL culture-1) compared to that in control condition (0.363 g mL culture-1). Coelastrum sp. showed higher scavenging activity (30.19%) when cultured in black light condition, indicating a correlation between the antioxidant activity and accumulation of astaxanthin. In this study, black light was shown to possess great potential to enhance the production of astaxanthin in microalgae.
  15. Fulltext Assessing the ecological risk of polycyclic aromatic hydrocarbons in sediments at Langkawi Island, Malaysia
    Nasher E, Heng LY, Zakaria Z, Surif S
    ScientificWorldJournal, 2013;2013:858309.
    PMID: 24163633 DOI: 10.1155/2013/858309
    Tourism-related activities such as the heavy use of boats for transportation are a significant source of petroleum hydrocarbons that may harm the ecosystem of Langkawi Island. The contamination and toxicity levels of polycyclic aromatic hydrocarbon (PAH) in the sediments of Langkawi were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Ten samples were collected from jetties and fish farms around the island in December 2010. A gas chromatography/flame ionization detector (GC/FID) was used to analyse the 18 PAHs. The concentration of total PAHs was found to range from 869 ± 00 to 1637 ± 20 ng g⁻¹ with a mean concentration of 1167.00 ± 24 ng g⁻¹, lower than the SQG effects range-low (3442 ng g⁻¹). The results indicated that PAHs may not cause acute biological damage. Diagnostic ratios and principal component analysis suggested that the PAHs were likely to originate from pyrogenic and petrogenic sources. The toxic equivalent concentrations of the PAHs ranged from 76.3 to 177 ng TEQ/g d.w., which is lower compared to similar studies. The results of mean effects range-median quotient of the PAHs were lower than 0.1, which indicate an 11% probability of toxicity effect. Hence, the sampling sites were determined to be the low-priority sites.
  16. Design and Analysis of Modified U-Shaped Four Element MIMO Antenna for Dual-Band 5G Millimeter Wave Applications
    Jetti CR, Addepalli T, Devireddy SR, Tanimki GK, Al-Gburi AJA, Zakaria Z, et al.
    Micromachines (Basel), 2023 Jul 31;14(8).
    PMID: 37630079 DOI: 10.3390/mi14081545
    A novel compact-slotted four element multiple input multiple output (MIMO) planar monopole antenna is proposed for 5G mmWave N257/N258 and N262 band applications. The antenna, with dimensions of 12 mm × 11.6 mm × 0.508 mm (1.036λo ×1.001λo×0.043λo where λo is computed at lowest cutoff frequency), is fabricated on a Rogers RT/duroid 5880 (tm) substrate with a relative permittivity of 2.2 and a dielectric loss tangent of 0.0009. The suggested antenna consists of four U-shaped radiating elements (patches) on top of the dielectric material and a slotted ground on the bottom. The radiating elements are fed by a 50-ohm microstrip line feed. To improve the impedance performance of the MIMO antenna, a rectangular strip of 1.3 mm × 0.2 mm and a couple of rectangular slots are added to each radiating element. The first operating band at 27.1 GHz, ranging from 25.9 GHz to 27.8 GHz, is achieved by using slotted U-shaped radiating elements. The second operating band at 48.7 GHz, ranging from 47.1 GHz to 49.9 GHz, is obtained by etching hexagonal slots on the ground. The antenna design achieves an isolation of >27 dB through the orthogonal positioning of radiating elements and slots on the ground. The designed antenna operates at 27 GHz (N257/N258) and 48.7 GHz (N262) bands, exhibiting stable radiation patterns, a peak gain of >5.95 dBi, radiation efficiency of >90%, an envelope correlation coefficient of <10-6, a total active reflection coefficient of ≤-10 dB, channel capacity losses of <0.03 bits/s/Hz, and a mean effective gain of ≤-3 dB. The simulated and measured results of the antenna show good agreement, making it well-suited for 5G mmWave communication applications.
  17. Antigenic potential of a recombinant polyvalent DNA vaccine against pathogenic leptospiral infection
    Garba B, Bahaman AR, Zakaria Z, Bejo SK, Mutalib AR, Bande F, et al.
    Microb Pathog, 2018 Nov;124:136-144.
    PMID: 30138761 DOI: 10.1016/j.micpath.2018.08.028
    Leptospirosis is a serious epidemic disease caused by pathogenic Leptospira species. The disease is endemic in most tropical and sub-tropical regions of the world. Currently, there is no effective polyvalent vaccine for prevention against most of the circulating serovars. Moreover, development of an efficient leptospiral vaccine capable of stimulating cross-protective immune responses against a wide range of serovars remains a daunting challenge. This, in part, is associated with the extensive diversity and variation of leptospiral serovars from region to region. In this study, a multi-epitope DNA vaccine encoding highly immunogenic epitopes from LipL32 and LipL41 was designed using in-silico approach. The DNA encoding antigenic epitopes was constructed from conserved pathogenic Leptospira genes (LipL32 and LipL41). Immunization of golden Syrian hamsters with the multi-epitope chimeric DNA vaccine resulted in the production of both agglutinating and neutralizing antibodies as evidence by MAT and in-vitro growth inhibition tests respectively. The antibodies produced reacted against eight different serovars and significantly reduced renal colonization following in vivo challenge. The vaccine was also able to significantly reduce renal colonization which is a very important factor responsible for persistence of leptospires among susceptible and reservoir animal hosts. In conclusion, the leptospiral multi-epitope chimeric DNA vaccine can serve as a potentially effective and safe vaccine against infection with different pathogenic leptospiral serovars.
  18. Preliminary analysis of the anti-inflammatory activity of essential oils of Zingiber zerumbet
    Zakaria ZA, Mohamad AS, Ahmad MS, Mokhtar AF, Israf DA, Lajis NH, et al.
    Biol Res Nurs, 2011 Oct;13(4):425-32.
    PMID: 21112917 DOI: 10.1177/1099800410386590
    Nonsteroidal anti-inflammatory drugs (NSAIDs) have been widely used for the treatment of inflammation. However, despite their effectiveness, most NSAIDs cause various side effects that negatively affect the management of inflammation and, in part, pain. Thus, there is a need to search for new anti-inflammatory agents with few, or no, side effects. Natural products of plant, animal, or microorganism origin have been good sources of new bioactive compounds. The present study was carried out to evaluate the acute and chronic anti-inflammatory activities of the essential oil of the rhizomes of Zingiber zerumbet (Zingiberaceae) using the carrageenan-induced paw edema and cotton pellet-induced granuloma tests, respectively. The effect of the essential oil on inflammatory- and noninflammatory-mediated pain was also assessed using the formalin test. Essential oil of Z. zerumbet, at doses of 30, 100, and 300 mg/kg, was administered intraperitoneally to rats. The substance exhibited significant anti-inflammatory activity both in acute and chronic animal models. The essential oil also inhibited inflammatory- and noninflammatory-mediated pain when assessed using the formalin test. In conclusion, the essential oil of Z. zerumbet possessed anti-inflammatory activity, in addition to its antinociceptive activity, which may explain its traditional uses to treat inflammatory-related ailments.
  19. Anti-inflammatory activity of the aqueous extract of ficus deltoidea
    Zakaria ZA, Hussain MK, Mohamad AS, Abdullah FC, Sulaiman MR
    Biol Res Nurs, 2012 Jan;14(1):90-7.
    PMID: 21278166 DOI: 10.1177/1099800410395378
    Ficus deltoidea (Family Moraceae) leaves have been used traditionally by the Malays to treat ailments such as wounds, sores, and rheumatism. The aim of the present study was to determine the anti-inflammatory activity of the aqueous extract of F. deltoidea leaf (FDA) using acute and chronic inflammatory models. FDA, in the doses of 30, 100, and 300 mg/kg, was administered intraperitoneally in rats (n = 6) before the animals were subjected to the carrageenan-induced paw edema test, cotton pellet-induced granuloma test, and formalin test. The first two tests represent acute and chronic models of inflammation, respectively. The first and second phases of the formalin test represent neurogenic pain and inflammatory-mediated pain, respectively; thus, only the second phase was measured in the present study. Results showed that FDA exerted significant (p < .05) anti-inflammatory activity in all assays, with dose-response effects seen in the paw edema and formalin tests. In conclusion, the leaf of F. deltoidea possesses anti-inflammatory activity against acute and chronic inflammatory responses and against pain-associated inflammatory response. These findings justify the traditional uses of F. deltoidea leaves for treatment of inflammatory-mediated ailments.
  20. Antinociceptive activity of a synthetic chalcone, flavokawin B on chemical and thermal models of nociception in mice
    Mohamad AS, Akhtar MN, Zakaria ZA, Perimal EK, Khalid S, Mohd PA, et al.
    Eur J Pharmacol, 2010 Nov 25;647(1-3):103-9.
    PMID: 20826146 DOI: 10.1016/j.ejphar.2010.08.030
    The present study examined the potential antinociceptive activity of flavokawin B (6'-hydroxy-2',4'-dimethoxychalcone), a synthetic chalcone using chemical- and thermal-induced nociception models in mice. It was demonstrated that flavokawin B (FKB; 0.3, 1, 3 and 10 mg/kg) administered via both oral (p.o.) and intraperitoneal (i.p.) routes produced significant and dose-dependent inhibition in the abdominal constrictions induced by acetic acid, with the i.p. route producing antinociception of approximately 7-fold more potent than the p.o. route. It was also demonstrated that FKB produced significant inhibition in the two phases of the formalin-induced paw licking test. In addition, the same treatment of flavokawin B (FKB) exhibited significant inhibition of the neurogenic nociceptive induced by intraplantar injections of glutamate and capsaicin. Likewise, this compound also induced a significant increase in the response latency period to thermal stimuli in the hot plate test and its antinociceptive effect was not related to muscle relaxant or sedative action. Moreover, the antinociception effect of the FKB in the formalin-induced paw licking test and the hot plate test was not affected by pretreatment of non-selective opioid receptor antagonist, naloxone. The present results indicate that FKB produced pronounced antinociception effect against both chemical and thermal models of pain in mice that exhibited both peripheral and central analgesic activity.
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