Editor, Author at Institute of Nano Electronic Engineering

Structural, electronic and thermodynamic properties of half-metallic Co2CrZ (Z=Ga, Ge and As) alloys: First-principles calculations

October 29, 2015 By Editor

Abstract – Abstract Using first principles calculations, the structural, electronic, and magnetic properties of ferromagnetic half-metallic full-Heusler Co2CrZ (Z=Ga,GeandAs) alloy via the FP-LAPW method in the generalized gradient (GGA) and GGA+U approximations are compared with other experimental and theoretical results. The calculated equilibrium lattice constants were in qualitative agreement with the previous results. The existence of the energy gap in the minority spin (DOS and band structure) of Co2CrZ (Z=Ga,GeandAs) are an indication of being a potential half-metallic ferromagnetic HMF. The half-metallicity of the obtained material may prove useful for applications in spin-polarizers and spin-injectors of magnetic nanodevices. The calculated total spin magnetic moments are almost exactly that expected from Slater-Pauling rule. Thermal effects on some macroscopic properties of Co2CrZ (Z=Ga,GeandAs) are predicted using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variations of the primitive cell volume, volume expansion coefficient, bulk modulus, heat capacity and Debye temperature with pressure and temperature in the ranges of 0-20 GPa and 0-3000 K, respectively are obtained successfully.

Corresponding Author: Uda Hashim
Corresponding Author’s Email: uda@unimap.edu.my

Full text: PDF

Non-Protein Coding RNA Genes as the Novel Diagnostic Markers for the Discrimination of Salmonella Species Using PCR

September 30, 2015 By Editor

Abstract – Salmonellosis, a communicable disease caused by members of the Salmonella species, transmitted to humans through contaminated food or water. It is of paramount importance, to generate accurate detection methods for discriminating the various Salmonella species that cause severe infection in humans, including S. Typhi and S. Paratyphi A. Here, we formulated a strategy of detection and differentiation of salmonellosis by a multiplex polymerase chain reaction assay using S. Typhi non-protein coding RNA (sRNA) genes. With the designed sequences that specifically detect sRNA genes from S. Typhi and S. Paratyphi A, a detection limit of up to 10 pg was achieved. Moreover, in a stool-seeding experiment with S. Typhi and S. Paratyphi A, we have attained a respective detection limit of 15 and 1.5 CFU/mL. The designed strategy using sRNA genes shown here is comparatively sensitive and specific, suitable for clinical diagnosis and disease surveillance, and sRNAs represent an excellent molecular target for infectious disease.

Corresponding Author: Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

Full text: PDF

Monitoring recombinant human erythropoietin abuse among athletes

September 30, 2015 By Editor

Abstract – The illegal administration of recombinant human erythropoietin (rHuEPO) among athletes is largely preferred over blood doping to enhance stamina. The advent of recombinant DNA technology allowed the expression of EPO-encoding genes in several eukaryotic hosts to produce rHuEPO, and today these performance-enhancing drugs are readily available. As a mimetic of endogenous EPO (eEPO), rHuEPO augments the oxygen carrying capacity of blood. Thus, monitoring the illicit use of rHuEPO among athletes is crucial in ensuring an even playing field and maintaining the welfare of athletes. A number of rHuEPO detection methods currently exist, including measurement of hematologic parameters, gene-based detection methods, glycomics, use of peptide markers, electrophoresis, isoelectric focusing (IEF)-double immunoblotting, aptamer/antibody-based methods, and lateral flow tests. This review gleans these different strategies and highlights the leading molecular recognition elements that have potential roles in rHuEPO doping detection.

Corresponding Author: Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

Full text: PDF

‘Spotted Nanoflowers’: Gold-seeded Zinc Oxide Nanohybrid for Selective Bio-capture

September 8, 2015 By Editor

Abstract – Hybrid gold nanostructures seeded into nanotextured zinc oxide (ZnO) nanoflowers (NFs) were created for novel biosensing applications. The selected ‘spotted NFs’ had a 30-nm-thick gold nanoparticle (AuNP) layer, chosen from a range of AuNP thicknesses, sputtered onto the surface. The generated nanohybrids, characterized by morphological, physical and structural analyses, were uniformly AuNP-seeded onto the ZnO NFs with an average length of 2–3 μm. Selective capture of molecular probes onto the seeded AuNPs was evidence for the specific interaction with DNA from pathogenic Leptospirosis-causing strains via hybridization and mis-match analyses. The attained detection limit was 100 fM as determined via impedance spectroscopy. High levels of stability, reproducibility and regeneration of the sensor were obtained. Selective DNA immobilization and hybridization were confirmed by nitrogen and phosphorus peaks in an X-ray photoelectron spectroscopy analysis. The created nanostructure hybrids illuminate the mechanism of generating multiple-target, high-performance detection on a single NF platform, which opens a new avenue for array-based medical diagnostics.

Corresponding Author: Uda Hashim
Corresponding Author’s Email: uda@unimap.edu.my

Full text: PDF

Design and fabrication of micro‑mixer with short turns angles for self‑generated turbulent structures

August 27, 2015 By Editor

Abstract – Micro mixing process is one of the most important drugs, synthesis and process technology. Many expectations toward enhanced fluids miscibility, yield and purity, improved safety, and access to new discovery are directed to the micro mixing technology. In microfluidic technology, mixer is the most important component because of its ability to operate either active or passive micro mixing. The study reports a simple inexpensive and cost effective micro mixer design/simulation/fabrication using 4.3a COMSOL Multi-physics software package and homemade photolithography equipment. The micro mixer was fabricated using PDMS and glass substrate with master mold fabricated with SU8 for rapid prototyping and reusability, the micro mixer and the whole mixer were fabricated in less than 20 min. Mixing profiles were observed for the efficiency evaluation by dropping four samples urine through the four inlets and collecting the sample at outlet. Flow rate and mixing efficiency were quantitatively measured by analyzing the recorded flow profiles and values of the image collected from the high powered microscope at inlet and outlet locations. and sample flow and mixing were compared for flowing efficiency and flow rate using different concentrations and the results indicate that the mixing efficiency of 98% was obtained at Reynolds number (Re) <2.

Corresponding Author: Uda Hashim
Corresponding Author’s Email: uda@unimap.edu.my