Displaying all 17 publications

Abstract:
Sort:
  1. Fulltext Brain in business: the economics of neuroscience
    Ahmad ZA
    Malays J Med Sci, 2010 Apr;17(2):1-3.
    PMID: 22135530
  2. Simulation of Lamb wave reflections at plate edges using the semi-analytical finite element method
    Ahmad ZA, Gabbert U
    Ultrasonics, 2012 Sep;52(7):815-20.
    PMID: 22727492 DOI: 10.1016/j.ultras.2012.05.008
    In typical Lamb wave simulation practices, effects of plate edge reflections are often not considered in order to simplify the wave signal interpretations. Methods that are based on infinite plates such as the semi-analytical finite element method is effective in simulating Lamb waves as it excludes the effect of plate edges. However, the inclusion of plate edges in a finite plate could render this method inapplicable, especially for transient response simulations. Here, by applying the ratio of Lamb mode reflections at plate edges, and representing the reflection at plate edges using infinite plate solutions, the semi-analytical finite element method can be applied for transient response simulation, even when the plate is no longer infinite.
  3. Effect of sintering temperature on the properties of modified mechanical alloyed CaCu3Ti4O12
    Hutagalung SD, Ying OL, Ahmad ZA
    IEEE Trans Ultrason Ferroelectr Freq Control, 2007 Dec;54(12):2587-91.
    PMID: 18276560 DOI: 10.1109/TUFFC.2007.582
    This paper presents the effects of calcination time and sintering temperature on the properties of CaCu(3)Ti(4)O(12). Electroceramic material of CaCu(3)Ti(4)O(12) was prepared using a modified mechanical alloying technique that covers several processes, which are preparation of raw material, mixing and ball milling for 5 hours, calcination, pellet forming and, sintering. The objective of this modified technique is to enable the calcination and sintering processes to be carried out at a shorter time and lower temperature. The x-ray diffraction (XRD) analysis result shows that a single-phase of CaCu(3)Ti(4)O(12) was completely formed by calcination at 750 degrees C for 12 hours. Meanwhile, the grain size of a sample sintered at 1050 degrees C for 24 hours is extremely large, in the range of 20-50 mum obtained from field emission scanning electron microscopy (FESEM) images. The dielectric constant value of 14,635 was obtained at 10 kHz by impedance (LCR) meter in the sintered sample at 1050 degrees C. However, the dielectric constant value of samples sintered at 900 and 950 degrees C is quite low, in the range of 52-119.
  4. Combination of hysteroscopic resection of endomyometrium with insertion of Mirena: An alternative treatment for adenomyosis
    Mohd Zahid AZ, Abdul Rahman N, Ahmad ZA
    Med J Malaysia, 2021 07;76(4):585-587.
    PMID: 34305125
    Adenomyosis is a common gynaecological condition encountered in clinical practice. Treatment of adenomyosis can present a great challenge to gynaecologists as women often become resistant to hormonal treatment eventually needing surgical intervention. Hysterectomy has long been the definitive treatment for adenomyosis. However, with women currently being diagnosed at an earlier age and still have not completed their family, there is an increasing demand for effective intervention with uterine conservation. We report here two cases of patients who had undergone a combination of hysteroscopic resection of the endomyometrium combined with Mirena insertion with successful outcome.
  5. A Short Review on Copper Calcium Titanate (CCTO) Electroceramic: Synthesis, Dielectric Properties, Film Deposition, and Sensing Application
    Ahmadipour M, Ain MF, Ahmad ZA
    Nanomicro Lett, 2016;8(4):291-311.
    PMID: 30460289 DOI: 10.1007/s40820-016-0089-1
    Electroceramic calcium copper titanates (CaCu3Ti4O12, CCTO), with high dielectric permittivities (ε) of approximately 105 and 104, respectively, for single crystal and bulk materials, are produced for a number of well-established and emerging applications such as resonator, capacitor, and sensor. These applications take advantage of the unique properties achieved through the structure and properties of CCTO. This review comprehensively focuses on the primary processing routes, effect of impurity, dielectric permittivity, and deposition technique used for the processing of electroceramics along with their chemical composition and micro and nanostructures. Emphasis is given to versatile and basic approaches that allow one to control the microstructural features that ultimately determine the properties of the CCTO ceramic. Despite the intensive research in this area, none of the studies available in the literature provides all the possible relevant information about CCTO fabrication, structure, the factors influencing its dielectric properties, CCTO immobilization, and sensing applications.
  6. First Report of Cabbage Soft Rot Caused by Pectobacterium carotovorum subsp. carotovorum in Malaysia
    Nazerian E, Sijam K, Mior Ahmad ZA, Vadamalai G
    Plant Dis, 2011 Apr;95(4):491.
    PMID: 30743350 DOI: 10.1094/PDIS-09-10-0683
    Cabbage (Brassica oleracea L. var. capitata L.) is one of the most important vegetables cultivated in Pahang and Kelantan, Malaysia. Pectobacterium carotovorum can cause soft rot on a wide range of crops worldwide, especially in countries with warm and humid climates such as Malaysia. Cabbage with symptoms of soft rot from commercial fields were sampled and brought to the laboratory during the winter of 2010. Disease symptoms were a gray to pale brown discoloration and expanding water-soaked lesions on leaves. Several cabbage fields producing white cultivars were investigated and 27 samples were collected. Small pieces of leaf samples were immersed in 5 ml of saline solution (0.80% NaCl) for 20 min to disperse the bacterial cells. Fifty microliters of the resulting suspension was spread on nutrient agar (NA) and King's B medium and incubated at 30°C for 48 h. Purification of cultures was repeated twice on these media. Biochemical and phenotypical tests gave these results: gram negative, rod shaped, ability to grow under liquid paraffin (facultative anaerobe); oxidase negative; phosphatase negative; positive degradation of pectate; sensitive to erythromycin; negative to Keto-methyl glucoside utilization, indole production and reduction sugars from sucrose were negative; acid production from sorbitol and arabitol was negative and from melibiose, citrate, and raffinose was positive. Hypersensitivity reaction on tobacco leaf with the injection of 106 CFU/ml of bacterial suspension for all strains was positive. Four representative strains were able to cause soft rot using cabbage slices (three replications) inoculated with a bacterial suspension at 106 CFU/ml. Inoculated cabbage slices were incubated in a moist chamber at 80% relative humidity and disease symptoms occurred after 24 h. Cabbage slices inoculated with water as a control remained healthy. The bacteria reisolated from rotted cabbage slices on NA had P. carotovorum cultural characteristics and could cause soft rot in subsequent tests. PCR amplification with Y1 and Y2 primers (1), which are specific for P. carotovorum, produced a 434-bp band with 15 strains. PCR amplification of the 16S-23S rRNA intergenic transcribed spacer region (ITS) using G1 and L1 primers gave two main bands approximately 535 and 580 bp and one faint band approximately 740 bp when electrophoresed through a 1.5% agarose gel. The ITS-PCR products were digested with RsaI restriction enzyme. According to biochemical and physiological characterictics (2), PCR-based pel gene (1), and analysis by ITS-PCR and ITS-restriction fragment length polymorphism (3), all isolates were identified as P. carotovorum subsp. carotovorum. This pathogen has been reported from Thailand, Indonesia, and Singapore with whom Malaysia shares its boundaries. To our knowledge, this is the first report of P. carotovorum subsp. carotovorum in cabbage from Malaysia. References: (1) A. Darraas et al. Appl. Environ. Microbiol. 60:1437, 1994. (2) N. W. Schaad et al. Laboratory Guide for the Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, 2001. (3) I. K. Toth et al. Appl. Environ. Microbiol. 67:4070, 2001.
  7. Use of waste gypsum to replace natural gypsum as set retarders in portland cement
    Chandara C, Azizli KA, Ahmad ZA, Sakai E
    Waste Manag, 2009 May;29(5):1675-9.
    PMID: 19131236 DOI: 10.1016/j.wasman.2008.11.014
    The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.
  8. Fulltext Imperata cylindrica sp as Novel Silica-Based Heterogeneous Catalysts for Transesterification of Palm Oil Mill Sludge
    Ngaini Z, Shahrom FD, Jamil N, Wahi R, Ahmad ZA
    J Oleo Sci, 2016 Jun 1;65(6):507-15.
    PMID: 27181252 DOI: 10.5650/jos.ess16014
    Biodiesel from palm oil mill sludge (POMS) was prepared in the presence of novel silica-based heterogeneous catalysts derived from Imperata cylindrica sp. Imperatacid and Imperatabase are two types of heterogeneous catalysts derived from Imperata cylindrica sp and characterized using scanning electron microscopy, Energy Dispersive X-ray, Brunauer-Emmett-Teller surface area and pore size measurement. Imperatacid has particle size of 43.1-83.9 µm while Imperatabase in the range of 89-193 µm. Imperatacid was conveniently applied in esterification step to afford > 90 wt% oil in 1:3 (oil/methanol) and 10 wt% catalyst, followed by transesterification with 1 wt% Imperatabase and 1:1 (oil/methanol) for 1 h at 65°C to afford 80% biodiesel with higher percentage of methyl palmitate (48.97%) and methyl oleate (34.14%) compare to conventional homogeneous catalyst. Reusability of the catalyst up to three times afforded biodiesel ranging from 78-80% w/w. The biodiesel was demonstrated onto alternative diesel engine (Megatech(®)-Mark III) and showed proportional increased of torque (ɽ) to biodiesel loading.
  9. Fulltext Life Table and Population Parameters of Nilaparvata lugens Stal. (Homoptera: Delphacidae) on Rice
    Win SS, Muhamad R, Ahmad ZA, Adam NA
    Trop Life Sci Res, 2011 May;22(1):25-35.
    PMID: 24575207 MyJurnal
    Survival and fertility characteristics of the brown planthopper (BPH), Nilaparvata lugens were assessed in the laboratory and field. Life tables and population parameters of the BPH were constructed in an environment with unlimited food supply and that was free of natural enemies. The highest mortality occurred in the immature stage, especially in the first and second instars. The life table analysis showed that the population density of BPH decreased gradually. The survival ratio of male to female was 0.512:0.488. The females lived for a maximum of 20 days. The trend of oviposition showed a peak at around the tenth day of the female life. The highest number of eggs produced per female per day was 9.63. The intrinsic rate of increase (rm) in egg production per female per day was 0.0677 and the daily finite of increase (λ) was 1.0688 females per female per day, with a mean generation time (T) of 34.05 days. The net reproductive rate (Ro) of the population was 10.02. The population doubling time (DT) was 10.42 days.
  10. Transplantation of human dental pulp stem cells: enhance bone consolidation in mandibular distraction osteogenesis
    Alkaisi A, Ismail AR, Mutum SS, Ahmad ZA, Masudi S, Abd Razak NH
    J Oral Maxillofac Surg, 2013 Oct;71(10):1758.e1-13.
    PMID: 24040948 DOI: 10.1016/j.joms.2013.05.016
    The main aim of the present study was to evaluate the capacity of stem cells from human exfoliated deciduous teeth (SHED) to enhance mandibular distraction osteogenesis (DO) in rabbits.
  11. Fulltext scFv antibody: principles and clinical application
    Ahmad ZA, Yeap SK, Ali AM, Ho WY, Alitheen NB, Hamid M
    Clin. Dev. Immunol., 2012;2012:980250.
    PMID: 22474489 DOI: 10.1155/2012/980250
    To date, generation of single-chain fragment variable (scFv) has become an established technique used to produce a completely functional antigen-binding fragment in bacterial systems. The advances in antibody engineering have now facilitated a more efficient and generally applicable method to produce Fv fragments. Basically, scFv antibodies produced from phage display can be genetically fused to the marker proteins, such as fluorescent proteins or alkaline phosphatase. These bifunctional proteins having both antigen-binding capacity and marker activity can be obtained from transformed bacteria and used for one-step immunodetection of biological agents. Alternatively, antibody fragments could also be applied in the construction of immunotoxins, therapeutic gene delivery, and anticancer intrabodies for therapeutic purposes. This paper provides an overview of the current studies on the principle, generation, and application of scFv. The potential of scFv in breast cancer research is also discussed in this paper.
  12. A Review on Microdialysis Calibration Methods: the Theory and Current Related Efforts
    Kho CM, Enche Ab Rahim SK, Ahmad ZA, Abdullah NS
    Mol Neurobiol, 2017 07;54(5):3506-3527.
    PMID: 27189617 DOI: 10.1007/s12035-016-9929-8
    Microdialysis is a sampling technique first introduced in the late 1950s. Although this technique was originally designed to study endogenous compounds in animal brain, it is later modified to be used in other organs. Additionally, microdialysis is not only able to collect unbound concentration of compounds from tissue sites; this technique can also be used to deliver exogenous compounds to a designated area. Due to its versatility, microdialysis technique is widely employed in a number of areas, including biomedical research. However, for most in vivo studies, the concentration of substance obtained directly from the microdialysis technique does not accurately describe the concentration of the substance on-site. In order to relate the results collected from microdialysis to the actual in vivo condition, a calibration method is required. To date, various microdialysis calibration methods have been reported, with each method being capable to provide valuable insights of the technique itself and its applications. This paper aims to provide a critical review on various calibration methods used in microdialysis applications, inclusive of a detailed description of the microdialysis technique itself to start with. It is expected that this article shall review in detail, the various calibration methods employed, present examples of work related to each calibration method including clinical efforts, plus the advantages and disadvantages of each of the methods.
  13. Fulltext Effect of MgO Addition on the Mechanical and Dynamic Properties of Zirconia Toughened Alumina (ZTA) Ceramics
    Arab A, Sktani ZDI, Zhou Q, Ahmad ZA, Chen P
    Materials (Basel), 2019 Jul 31;12(15).
    PMID: 31370216 DOI: 10.3390/ma12152440
    Zirconia toughened alumina (ZTA) is a promising advanced ceramic material for a wide range of applications that are subjected to dynamic loading. Therefore, the investigation of dynamic compressive strength, fracture toughness and hardness is essential for ZTA ceramics. However, the relationship between these mechanical properties in ZTA has not yet been established. An example of this relationship is demonstrated using ZTA samples added with MgO prepared through conventional sintering. The microstructure and mechanical properties of ZTA composites were characterized. The hardness of ZTA composites increased for ≤0.7 wt.% MgO due to the pinning effect of MgO and decrease of the porosity in the microstructure. Oppositely, the fracture toughness of ZTA composites continuously decreased due to the size reduction of Al2O3 grains. This is the main reason of deteriorate of dynamic compressive strength more than 0.2 wt.% of MgO addition. Therefore, the SHPB test shows the improvement of the dynamic compressive strength only up to a tiny amount (0.2 wt.% of MgO addition) into ZTA ceramics.
  14. Endometrioma Presented as Acute Abdomen in a Peritoneal Dialysis Patient: A Case Report and Literature Review
    Ahmad ZA, Ramly F, Mohd Zahid AZ, Abdullah B, Abdul Hafidz MI
    Int J Womens Health, 2021;13:639-644.
    PMID: 34234575 DOI: 10.2147/IJWH.S304818
    Laparoscopic management in patients on peritoneal dialysis offers good postoperative outcome and early resumption to peritoneal dialysis. This is a report of a 43-year-old woman with end-stage kidney disease on peritoneal dialysis presented with left iliac fossa pain due to a large endometrioma. Emergency diagnostic laparoscopy was performed with careful laparoscopic entry, Tenckhoff catheter care and anti-adhesive application. The patient underwent temporary hemodialysis for two weeks before full resumption to peritoneal dialysis. She was planned for GnRH analogue for three months post-operatively. In conclusion, laparoscopy is a safe and advantageous route of surgery for ovarian endometrioma in patients on peritoneal dialysis. However, mindful surgical strategies are needed to ensure the Tenckhoff catheter's longevity and early resumption to peritoneal dialysis post-operatively.
  15. Room temperature LPG resistive sensor based on the use of a few-layer graphene/SnO2 nanocomposite
    Goutham S, Bykkam S, Sadasivuni KK, Kumar DS, Ahmadipour M, Ahmad ZA, et al.
    Mikrochim Acta, 2017 12 20;185(1):69.
    PMID: 29594642 DOI: 10.1007/s00604-017-2537-0
    A nanocomposite consisting of a few layers of graphene (FLG) and tin dioxide (SnO2) was prepared by ultrasound-assisted synthesis. The uniform SnO2 nanoparticles (NPs) on the FLG were characterized by X-ray diffraction in terms of lattice and phase structure. The functional groups present in the composite were analyzed by FTIR. Electron microscopy (HR-TEM and FE-SEM) was used to study the morphology. The effect of the fraction of FLG present in the nanocomposite was investigated. Sensitivity, selectivity and reproducibility towards resistive sensing of liquid propane gas (LPG) was characterized by the I-V method. The sensor with 1% of FLG on SnO2 operated at a typical voltage of 1 V performs best in giving a rapid and sensitive response even at 27 °C. This proves that the operating temperature of such sensors can be drastically decreased which is in contrast to conventional metal oxide LPG sensors. Graphical abstract Schematic of a room temperature gas sensor for liquefied petroleum gas (LPG). It is based on the use of a few-layered graphene (1 wt%)/SnO2 nanocomposite that was deposited on an interdigitated electrode (IDEs). A sensing mechanism for LPG detection has been established.
  16. Inhibition of aflatoxin biosynthesis in Aspergillus flavus by phenolic compounds extracted of Piper betle L
    Yazdani D, Mior Ahmad ZA, Yee How T, Jaganath IB, Shahnazi S
    Iran J Microbiol, 2013 Dec;5(4):428-33.
    PMID: 25848517
    BACKGROUND AND OBJECTIVES: Food contamination by aflatoxins is an important food safety concern for agricultural products. In order to identify and develop novel antifungal agents, several plant extracts and isolated compounds have been evaluated for their bioactivities. Anti-infectious activity of Piper betle used in traditional medicine of Malaysia has been reported previously.

    MATERIALS AND METHODS: Crude methanol extract from P. betel powdered leaves was partitioned between chloroform and water. The fractions were tested against A. flavus UPMC 89, a strong aflatoxin producing strain. Inhibition of mycelial growth and aflatoxin biosynthesis were tested by disk diffusion and macrodillution techniques, respectively. The presence of aflatoxin was determined by thin-layer chromatography (TLC) and fluorescence spectroscopy techniques using AFB1 standard. The chloroform soluble compounds were identified using HPLC-Tandem mass spectrometry technique.

    RESULTS: The results, evaluated by measuring the mycelial growth and quantification of aflatoxin B1(AFLB1) production in broth medium revealed that chloroform soluble compounds extract from P. betle dried leaves was able to block the aflatoxin biosynthesis pathway at concentration of 500μg/ml without a significant effect on mycelium growth. In analyzing of this effective fractions using HPLC-MS(2) with ESI ionization technique, 11 phenolic compounds were identified.

    CONCLUSION: The results showed that the certain phenolic compounds are able to decline the aflatoxin production in A. flavus with no significant effect on the fungus mycelia growth. The result also suggested P. betle could be used as potential antitoxin product.

  17. Oncologist-led BRCA counselling improves access to cancer genetic testing in middle-income Asian country, with no significant impact on psychosocial outcomes
    Yoon SY, Wong SW, Lim J, Ahmad S, Mariapun S, Padmanabhan H, et al.
    J Med Genet, 2022 Mar;59(3):220-229.
    PMID: 33526602 DOI: 10.1136/jmedgenet-2020-107416
    BACKGROUND: Identifying patients with BRCA mutations is clinically important to inform on the potential response to treatment and for risk management of patients and their relatives. However, traditional referral routes may not meet clinical needs, and therefore, mainstreaming cancer genetics has been shown to be effective in some high-income and high health-literacy settings. To date, no study has reported on the feasibility of mainstreaming in low-income and middle-income settings, where the service considerations and health literacy could detrimentally affect the feasibility of mainstreaming.

    METHODS: The Mainstreaming Genetic Counselling for Ovarian Cancer Patients (MaGiC) study is a prospective, two-arm observational study comparing oncologist-led and genetics-led counselling. This study included 790 multiethnic patients with ovarian cancer from 23 sites in Malaysia. We compared the impact of different method of delivery of genetic counselling on the uptake of genetic testing and assessed the feasibility, knowledge and satisfaction of patients with ovarian cancer.

    RESULTS: Oncologists were satisfied with the mainstreaming experience, with 95% indicating a desire to incorporate testing into their clinical practice. The uptake of genetic testing was similar in the mainstreaming and genetics arm (80% and 79%, respectively). Patient satisfaction was high, whereas decision conflict and psychological impact were low in both arms of the study. Notably, decisional conflict, although lower than threshold, was higher for the mainstreaming group compared with the genetics arm. Overall, 13.5% of patients had a pathogenic variant in BRCA1 or BRCA2, and there was no difference between psychosocial measures for carriers in both arms.

    CONCLUSION: The MaGiC study demonstrates that mainstreaming cancer genetics is feasible in low-resource and middle-resource Asian setting and increased coverage for genetic testing.

Related Terms
    Try searching for something
Filters
Contact Us

Please provide feedback to Administrator ([email protected])

External Links