MyMedR

Displaying all 13 publications

Abstract:

Sort:

Fulltext Scalable Mesoporous Platinum Diselenide Nanosheet Synthesis in Water

Ali Umar A, Md Saad SK, Mat Salleh M

ACS Omega, 2017 Jul 31;2(7):3325-3332.
PMID: 31457657 DOI: 10.1021/acsomega.7b00580

Newly discovered two-dimensional (2D) atomic crystals (nanosheet) of platinum diselenide (PtSe2) have progressively attracted attention due to their expected high performance in catalysis, sensing, electronics, and optoelectronics applications. Further extraordinary physicochemical properties are expected if these nanosheets of platinum diselenide can possess mesoporosity as this may enable a high range of molecular adsorption, enhancing their functionalities in catalysis, batteries, supercapacitors, and sensing. Here, we present for the first time a straightforward, aqueous-phase synthetic strategy for the preparation of scalable nanosheets of platinum diselenide with mesoporous structure via a surfactant-templated self-assembly followed by a thermal annealing phase-transformation process. We used hexamethylenetetramine as a hexagonal honeycomb (sp2-sp3 orbital) scaffold for assembling the Pt and Se organic complexes to form the nanosheet structure, which is stable, preserving the 2D structure and mesoporosity during a thermal annealing at 500 °C. Density functional theory analysis then indicated that the mesoporous nanosheets of platinum diselenide exhibit a high free-energy and large density of π electrons crossing the Fermi level, inferring a high-catalytic performance. This effortless strategy is currently being extended to the synthesis of other transition metal dichalcogenides, including the preparation of multi-metal atomic dichalcogenide nanosheets, for a wide variety of scientific and technological applications.
Markedly raised haemolysis index with upper limit of normal serum potassium levels

Kathiravelu Z, Thambiah SC, Mat Salleh MJ, Samsudin IN

Malays J Pathol, 2021 Apr;43(1):101-107.
PMID: 33903313

INTRODUCTION: Haemolytic specimens are a frequent occurrence in clinical laboratories, and they interfere with the analysis of many tests.
CASE REPORT: We describe here an unusual case of leptospirosis complicated by haemolytic anaemia in a 70-year-old man with established kidney failure. He presented with an abrupt onset of shortness of breath, flushing and erythematous rash after completing haemodialysis. The patient's biochemistry test samples were however rejected twice as they were grossly haemolysed. The integrated auto-verification alert system implemented in the hospital's laboratory information system alerted the staff of the possibility of in vivo haemolysis.
DISCUSSION: The auto-verification alert system effectively distinguishes between in vitro and in vivo haemolysis and as such can be utilised as a diagnostic aid in patients with suspected intravascular haemolysis.
Fulltext Direct deposition of silver nanoplates on quartz surface by sequence pre-treatment hydroxylation and silanisation

Abu Bakar N, Mat Salleh M, Ali Umar A, Shapter JG

MethodsX, 2017;4:486-491.
PMID: 29201649 DOI: 10.1016/j.mex.2017.11.008

Silver nanoparticles deposited on quartz substrates are widely used as SERS substrates. The nanoparticles can be deposited directly from colloidal solution by dipping technique. However, the adhesion of the particles on the quartz surface is very poor. Normally the substrate is pre-treated with hydroxylation or silanisation process. In this paper, we have demonstrated that the application of the sequence pre-treatment hydroxylation and silanisation have improved the density of silver nanoplates desposited on the quartz surface. •Sequence hydroxylation and silanisation pre-treatment assists the deposition of the nanoplate on the surface.•Various immersion times of the quartz surface into the colloidal nanoplates determined size distributions and density surface of the nanoplates on the surface.
Fulltext Gold Nanoplates for a Localized Surface Plasmon Resonance-Based Boric Acid Sensor

Morsin M, Mat Salleh M, Ali Umar A, Sahdan MZ

Sensors (Basel), 2017 Apr 25;17(5).
PMID: 28441323 DOI: 10.3390/s17050947

Localized surface plasmon resonance (LSPR) properties of metallic nanostructures, such as gold, are very sensitive to the dielectric environment of the material, which can simply be adjusted by changing its shape and size through modification of the synthesizing process. Thus, these unique properties are very promising, particularly for the detection of various types of chemicals, for example boric acid which is a non-permitted preservative employed in food preparations. For the sensing material, gold (Au) nanoplates with a variety of shapes, i.e., triangular, hexagonal, truncated pentagon and flat rod, were prepared using a seed-mediated growth method. The yield of Au nanoplates was estimated to be ca. 63% over all areas of the sensing material. The nanoplates produced two absorption bands, i.e., the transverse surface plasmon resonance (t-SPR) and the longitudinal surface plasmon resonance (l-SPR) at 545 nm and 710 nm, respectively. In the sensing study, these two bands were used to examine the response of gold nanoplates to the presence of boric acid in an aqueous environment. In a typical process, when the sample is immersed into an aqueous solution containing boric acid, these two bands may change their intensity and peak centers as a result of the interaction between the boric acid and the gold nanoplates. The changes in the intensities and peak positions of t-SPR and l-SPR linearly correlated with the change in the boric acid concentration in the solution.
Efficient heterogeneous catalytic hydrogenation of acetone to isopropanol on semihollow and porous palladium nanocatalyst

Balouch A, Ali Umar A, Shah AA, Mat Salleh M, Oyama M

ACS Appl Mater Interfaces, 2013 Oct 9;5(19):9843-9.
PMID: 24025235 DOI: 10.1021/am403087m

Highly efficient and remarkable selective acetone conversion to isopropanol has been achieved via a heterogeneous catalytic hydrogenation of acetone by NaBH4 in the presence of semihollow palladium nanoparticles (PdNPs) grown on ITO substrate. PdNPs with high surface defect grown on an indium tin oxide (ITO) surface were prepared via a simple immersion of the substrate into a solution containing K2PdCl6, sodium dodecyl sulphate (SDS), and formic acid for 2 h at room temperature. The sample showed remarkably high heterogeneous catalytic efficiency by producing 99.8% of isopropanol within 6 min using only 0.28 μg of PdNPs on the ITO surface. The present system exhibits heterogenenous catalytic hydrogenation efficiency 1 × 10(6) time higher than using the conventional Raney Ni system.
Fulltext A simple route to vertical array of quasi-1D ZnO nanofilms on FTO surfaces: 1D-crystal growth of nanoseeds under ammonia-assisted hydrolysis process

Ali Umar A, Abd Rahman MY, Taslim R, Mat Salleh M, Oyama M

Nanoscale Res Lett, 2011 Oct 25;6:564.
PMID: 22027275 DOI: 10.1186/1556-276X-6-564

A simple method for the synthesis of ZnO nanofilms composed of vertical array of quasi-1D ZnO nanostructures (quasi-NRs) on the surface was demonstrated via a 1D crystal growth of the attached nanoseeds under a rapid hydrolysis process of zinc salts in the presence of ammonia at room temperature. In a typical procedure, by simply controlling the concentration of zinc acetate and ammonia in the reaction, a high density of vertically oriented nanorod-like morphology could be successfully obtained in a relatively short growth period (approximately 4 to 5 min) and at a room-temperature process. The average diameter and the length of the nanostructures are approximately 30 and 110 nm, respectively. The as-prepared quasi-NRs products were pure ZnO phase in nature without the presence of any zinc complexes as confirmed by the XRD characterisation. Room-temperature optical absorption spectroscopy exhibits the presence of two separate excitonic characters inferring that the as-prepared ZnO quasi-NRs are high-crystallinity properties in nature. The mechanism of growth for the ZnO quasi-NRs will be proposed. Due to their simplicity, the method should become a potential alternative for a rapid and cost-effective preparation of high-quality ZnO quasi-NRs nanofilms for use in photovoltaic or photocatalytics applications.PACS: 81.07.Bc; 81.16.-c; 81.07.Gf.
Determination of salivary cortisol reference interval in a selected Malaysian population

Choo JE, Samsudin IN, Mat Salleh MJ, Zahari Sham SY, Thambiah SC

Malays J Pathol, 2020 Dec;42(3):433-437.
PMID: 33361725

INTRODUCTION: Salivary cortisol is used as an indicator of stress level and a recommended screening test for Cushing syndrome. The normal reference interval for salivary cortisol is dependent on the analytical methodology and the population studied and hence, establishment of a local population-based reference interval is recommended.
MATERIALS AND METHODS: A total of 129 healthy blood donors and staffs of Penang General Hospital were recruited from June 2018-May 2019. Paired (morning and late-night) saliva samples were collected from individuals aged between 18 and 60 years old with no history of chronic medical illness. Salivary cortisol was assayed using electrochemiluminescence immunoassay technique. Non-parametric statistics were used for calculation of reference interval and 90% confidence intervals (90% CIs).
RESULTS: The reference interval for morning and latenight salivary cortisol was 2.09 - 22.63 nmol/L and <12.00 nmol/L, respectively.
CONCLUSION: The locally-derived adult reference intervals for morning and late-night salivary cortisol concentration was determined and varied with previous studies emphasising the need in establishing individual laboratory reference interval.
Fulltext One-step wet chemical synthesis of gold nanoplates on solid substrate using poly-l-lysine as a reducing agent

Nafisah S, Morsin M, Jumadi NA, Nayan N, Md Shah NZA, Razali NL, et al.

MethodsX, 2018;5:1618-1625.
PMID: 30568883 DOI: 10.1016/j.mex.2018.12.002

A one-step wet chemical approach or seedless growth process has several advantages compared to the traditional seed-mediated growth method (SMGM), such as being simpler and not requiring a multistep growth of seeds. This study had introduced a one-step wet chemical method to synthesis gold nanoplates on a solid substrate. The synthesis was carried out by simply immersing clean ITO substrate into a solution, which was made from mixing of gold chloride (precursor), cetyltrimethylammonium bromide or CTAB (stabilizing agent), and poly-l-lysine or PLL (reducing agent). Consequently, the size of the nanoplates in the range of (0.40 - 0.89) μm and a surface density within the range (21.89-57.19) % can be easily controlled by changing the concentration of PLL from 0.050 to 0.100 w/v % in H2O. At low PLL concentrations, the reduction of the gold precursor by PLL is limited, leading to the formation of gold nanoplates with a smaller size and surface density. The study on the sample by using energy-dispersive x-ray spectroscopy (EDS) confirmed that gold peaks occurred. The optical properties of the samples were examined by a UV-vis Spectrophotometer and showed that there was no strong surface plasmon resonance band observed at UV-vis and infrared regions, which agreed to micron-sized gold nanoplates. •Gold nanoplates synthesized on the substrate using a simple one-step wet chemical synthesis approach with poly-l-lysine (PLL) as a reducing agent and CTAB as a stabilizing agent.•The nanoplate's size and surface density was strongly dependent on the concentration of PLL.•Gold nanoplates synthesized using PLL with a concentration 0.050% showed perfect triangular shape, less by-products and more homogenous in size.
Ag-ZnO nanoreactor grown on FTO substrate exhibiting high heterogeneous photocatalytic efficiency

Tan ST, Ali Umar A, Balouch A, Nafisah S, Yahaya M, Yap CC, et al.

ACS Comb Sci, 2014 Jul 14;16(7):314-20.
PMID: 24919039 DOI: 10.1021/co400157m

This Research Article reports an unusually high efficiency heterogeneous photodegradation of methyl orange (MO) in the presence of Ag nanoparticle-loaded ZnO quasi-nanotube or nanoreactor (A-ZNRs) nanocatalyst grown on FTO substrate. In typical process, photodegradation efficiency of as high as 21.6% per μg per Watts of used catalyst and UV power can be normally obtained within only a 60-min reaction time from this system, which is 10(3) order higher than the reported results. This is equivalent to the turnover frequency of 360 mol mol(-1) h(-1). High-density hexagonal A-ZNRs catalysts were grown directly on FTO substrate via a seed-mediated microwave-assisted hydrolysis growth process utilizing Ag nanoparticle of approximately 3 nm in size as nanoseed and mixture aqueous solution of Zn(NO3)·6H2O, hexamethylenetetramine (HMT), and AgNO3 as the growth solution. A-ZNRs adopts hexagonal cross-section morphology with the inner surface of the reactor characterized by a rough and rugged structure. Transmission electron microscopy imaging shows the Ag nanoparticle grows interstitially in the ZnO nanoreactor structure. The high photocatalytic property of the A-ZNRs is associated with the highly active of inner side's surface of A-ZNRs and the oxidizing effect of Ag nanoparticle. The growth mechanism as well as the mechanism of the enhanced-photocatalytic performance of the A-ZNRs will be discussed.
Synthesis of amorphous platinum nanofibers directly on an ITO substrate and its heterogeneous catalytic hydrogenation characterization

Balouch A, Ali Umar A, Mawarnis ER, Md Saad SK, Mat Salleh M, Abd Rahman MY, et al.

ACS Appl Mater Interfaces, 2015 Apr 15;7(14):7776-85.
PMID: 25807116 DOI: 10.1021/acsami.5b01012

This paper reports a facile, solution-phase approach to synthesizing a one-dimensional amorphous face-centered-cubic (fcc) platinum (a-Pt) nanostructure (nanofibers) directly on an indium-tin oxide (ITO) substrate. The electron microscopy analysis result shows that the a-Pt nanofiber has a diameter and length of approximately 50 nm and 1 μm, respectively, and is grown in high density on the entire surface of the ITO substrate. The X-ray photoelectron spectroscopy analysis result further reveals that the a-Pt nanofibers feature metallic properties with highly reactive surface chemistry, promising novel performance in electrochemistry, catalysis, and sensors. A synergetic interplay between the formic acid reducing agent and the hexamethylenetetramine surfactant in the reduction of Pt ions is assumed as the driving force for the formation of the amorphous phase in the Pt nanostructure. The catalytic properties of a-Pt were examined in the acetone hydrogenation reaction under microwave irradiation. a-Pt shows excellent heterogeneous catalytic properties for converting acetone to isopropyl alcohol with turnover number and frequency as high as 400 and 140 min(-1), respectively. The preparation and formation mechanism of the a-Pt nanofibers will be discussed in detail in this paper.
Fulltext Two-Dimensional, Hierarchical Ag-Doped TiO2 Nanocatalysts: Effect of the Metal Oxidation State on the Photocatalytic Properties

Md Saad SK, Ali Umar A, Ali Umar MI, Tomitori M, Abd Rahman MY, Mat Salleh M, et al.

ACS Omega, 2018 Mar 31;3(3):2579-2587.
PMID: 31458546 DOI: 10.1021/acsomega.8b00109

This paper reports the synthesis of two-dimensional, hierarchical, porous, and (001)-faceted metal (Ag, Zn, and Al)-doped TiO2 nanostructures (TNSs) and the study of their photocatalytic activity. Two-dimensional metal-doped TNSs were synthesized using the hydrolysis of ammonium hexafluorotitanate in the presence of hexamethylenetetramine and metal precursors. Typical morphology of metal-doped TNSs is a hierarchical nanosheet that is composed of randomly stacked nanocubes (dimensions of up to 5 μm and 200 nm in edge length and thickness, respectively) and has dominant (001) facets exposed. Raman analysis and X-ray photoelectron spectroscopy results indicated that the Ag doping, compared to Zn and Al, much improves the crystallinity degree and at the same time dramatically lowers the valence state binding energy of the TNS and provides an additional dopant oxidation state into the system for an enhanced electron-transfer process and surface reaction. These are assumed to enhance the photocatalytic of the TNS. In a model of photocatalytic reaction, that is, rhodamine B degradation, the AgTNS demonstrates a high photocatalytic activity by converting approximately 91% of rhodamine B within only 120 min, equivalent to a rate constant of 0.018 m-1 and ToN and ToF of 94 and 1.57 min-1, respectively, or 91.1 mmol mg-1 W-1 degradation when normalized to used light source intensity, which is approximately 2 times higher than the pristine TNS and several order higher when compared to Zn- and Al-doped TNSs. Improvement of the crystallinity degree, decrease in the defect density and the photogenerated electron and hole recombination, and increase of the oxygen vacancy in the AgTNS are found to be the key factors for the enhancement of the photocatalytic properties. This work provides a straightforward strategy for the preparation of high-energy (001) faceted, two-dimensional, hierarchical, and porous Ag-doped TNSs for potential use in photocatalysis and photoelectrochemical application.
Fulltext Are Dropped Bone Grafts Safe to be Re-used? - An Experimental Study Comparing Efficacy of Chlorhexidine, Povidone-Iodine and Alcohol

Mat-Salleh MF, Sadagatullah AN, Ibrahim MY, Abdul-Aziz I, Wan-Abdullah WA, Maning N, et al.

Malays Orthop J, 2021 Jul;15(2):70-76.
PMID: 34429825 DOI: 10.5704/MOJ.2107.011

Introduction: A dilemma arises when a bone graft or fracture fragment is accidentally dropped on the operation theatre floor and becomes contaminated. This study aimed to determine the efficacy of simple and readily available antiseptic solutions in disinfecting contaminated bones.
Material and Methods: This experimental study involved 225 bone specimens prepared from discarded bone fragments during a series of 45 knee and hip arthroplasty surgeries. The bone fragments were cut into five identical cubes and were randomly assigned to either control (positive or negative), or experimental groups (0.5% chlorhexidine, 10% povidone-iodine or 70% alcohol). The control negative was to determine pre-contamination culture. All bone specimens, except the control negative group were uniformly contaminated by dropping on the operation theatre floor. Subsequently, the dropped bone specimens except for the control positive group, were disinfected by immersing in a respective antiseptic solution for 10 minutes, before transported to the microbiology laboratory for incubation.
Results: The incidence of a positive culture from a dropped bone fragment was 86.5%. From the 37 specimens sent for each group, the incidence of positive culture was 5.4% (2 specimens) after being disinfected using chlorhexidine, 67.6% (25 specimens) using povidone-iodine and 81.1% (30 specimens) using alcohol. Simple logistic regression analysis demonstrated that chlorhexidine was significantly effective in disinfecting contaminated bones (p-value <0.001, odd ratio 0.009). Povidone-iodine and alcohol were not statistically significant (p-value 0.059 and 0.53, respectively). Organisms identified were Bacillus species and coagulase negative Staphylococcus. No gram-negative bacteria were isolated.
Conclusion: A total of 0.5% chlorhexidine is effective and superior in disinfecting contaminated bones.
Survey on serum protein electrophoresis and recommendations for standardised reporting

Sthaneshwar P, Thambiah SC, Mat Salleh MJ, Nasuruddin DN, Ahmad Zabidi NF, Jelani AM, et al.

Malays J Pathol, 2021 Aug;43(2):281-290.
PMID: 34448792

INTRODUCTION: Serum protein electrophoresis (SPE) is a well-established laboratory technique. However, reporting of results varies considerably between laboratories. The variation in reporting can cause confusion to the clinician with a potential of adversely impacting patient care. The purpose of the survey was to find out the variation in reporting and to prepare recommendations to the Malaysian laboratories based on the survey to reduce both the variation in reporting between laboratories and the risk of misinterpretation of reports.
MATERIALS AND METHODS: To determine the extent of variation in reporting of protein electrophoresis results questionnaires were distributed to the pathologists of various laboratories in Malaysia regarding the method, quantification of paraprotein concentrations and immunoglobulin assays, and information regarding current laboratory electrophoresis practices.
RESULTS: Variation was found in the following reporting practices: (a) screening protocol; (b) reporting of serum albumin; (c) numerical reporting of protein fractions and paraprotein; (d) co-migration of a paraprotein with a normal serum protein; (e) reporting of multiple paraprotein bands (f) appearance of small abnormal band and oligoclonal bands and (g) communication about of interferences.
CONCLUSION: The pathologists of the country made recommendations on the reporting of protein electrophoresis. Harmonised reporting will reduce inconsistency, variation in reporting, improve the quality of the report and most importantly improve patient care.

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links