Uda Hashim
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Preferred name
Uda Hashim
Official Name
Uda, Hashim
Alternative Name
Hashimb, U.
Hashim, Uda
Hashim, U.
Uda, Hashim
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Scopus Author ID
22633937800
Researcher ID
CVC-6955-2022

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Effect of Different Etching Time on Fabrication of an Optoelectronic Device Based on GaN/Psi

2023-01-01 , Jabbar H.D. , Fakhri M.A. , Razzaq M.J.A. , Omar S. Dahham , Salim E.T. , Alsultany F.H. , Uda Hashim

Gallium nitride (GaN)/porous silicon (PSi) film was prepared using a pulsed laser deposition method and 1064 nm Nd: YAG laser for optoelectronic applications and a series of Psi substrates were fabricated using a photoelec-trochemical etching method assisted by laser at different etching times for 2.5–15 min at 2.5 min intervals. X-ray diffraction, room-temperature photoluminescence, atomic force microscopy and field emission scanning electron microscopy images, and electrical characteristics in the prepared GaN on the Psi film were investigated. The opti-mum Psi substrate was obtained under the following conditions: 10 min, 10 mA/cm2, and 24% hydrofluoric acid. The substrate exhibited two highly cubic crystalline structures at (200) and (400) orientations and yellow visible band photoluminescence, and homogeneous pores formed over the entire surface. The pores had steep oval shapes and were accompanied by small dark pores that appeared topographically and morphologically. The GaN/Psi film fabricated through PLD exhibited a high and hexagonal crystallographic texture in the (002) plane. Spectroscopic properties results revealed that the photoluminescence emission of the deposited nano-GaN films was in the ultraviolet band (374 nm) related to GaN material and in the near-infrared band (730 nm) related to the Psi substrate. The topographical and morphological results of the GaN films confirmed that the deposited film contained spherical grains with an average diameter of 51.8 nm and surface roughness of 4.8 nm. The GaN/Psi surface showed a cauliflower-like morphology, and the built-in voltage decreased from 3.4 to 2.7 eV after deposi-tion. The fabricated GaN/Psi film exhibited good electrical characteristics.

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Titanium dioxide–mediated resistive nanobiosensor for E. coli O157:H7

2020-04-01 , Nadzirah S. , Uda Hashim , Subash Chandra Bose Gopinath , Nor Azizah Parmin , Hamzah A.A. , Yu H.W. , Dee C.F.

A titanium dioxide nanoparticle (TiO2 NP)–mediated resistive biosensor is described for the determination of DNA fragments of Escherichia coli O157:H7 (E. coli O157:H7). The sol-gel method was used to synthesize the TiO2 NP, and microlithography was applied to fabricate the interdigitated sensor electrodes. Conventional E. coli DNA detections are facing difficulties in long-preparation-and-detection-time (more than 3 days). Hence, electronic biosensor was introduced by measuring the current-voltage (I–V) DNA probe without amplification of DNA fragments. The detection scheme is based on the interaction between the electron flow on the sensor and the introduction of negative charges from DNA probe and target DNA. The biosensor has a sensitivity of 1.67 × 1013 Î©/M and a wide analytical range. The limit detection is down to 1 × 10−11 M of DNA. The sensor possesses outstanding repeatability and reproducibility and is cabable to detect DNA within 15 min in a minute-volume sample (1 Î¼L). [Figure not available: see fulltext.].

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Integration of Aluminium Interdigitated Electrodes with Zinc Oxide as Nanocomposite for Selectively Detect Alpha-Synuclein for Parkinson's Disease Diagnosis

2021-12-14 , Adam H. , Subash Chandra Bose Gopinath , Uda Hashim

Parkinson's disease is associated with motor and non-motor symptoms, mostly a motor symptom such as tremor is said to be an early indication for Parkinson's disease development. Because of higher demands for faster and more precise diagnostic methods, it has sparked trends in the development of a biosensor for the diagnosis of Parkinson's disease. Therefore, this study has fabricated a biosensor that is capable of detecting a specific Parkinson's disease biomarker such as aggregation of alpha synuclein and this is crucial in reducing the burden of Parkinson's disease and to be able to detect the disease at the earlier stage. Finding the inconsistent aggregation of alpha-synuclein is a promising method for the early detection of Parkinson's disease. Using conventional photographic process, aluminium interdigitated electrodes (ALIDEs) have been fabricated and employed with sensitive electrochemical strategy for the specific detection of the Parkinson's disease antigen (alpha synuclein). The microelectrode was developed based on aluminium electrode sputtered on silicon substrate. Further, zinc oxide (ZnO) was deposited by sputtering on the working electrode of the ALIDEs using a spin-coating method. The ZnO nanocomposite onto aluminium microelectrode surface provides a favourable platform for efficient loading of antibody via binding with antigen alpha synuclein. The effective loading of the biomolecules (antibody and antigen) on the ZnO nanocomposite surface modified aluminium microelectrode was observed by SEM, AFM and 3D Profilometer. The current flow for each concentration of alpha synuclein was observed at 7.5×10−6 A (10 fM), 8.8×10−6 A (100 fM), and 8.5×10−6 A (1 pM) respectively.

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Silica Titania optical thick film by multi-spinning sol-gel process

2006 , Mohamad Zahid A. Malek , Uda Hashim , Mat Tamizi Hj Zainuddin , Ahmad Makarimi Abdullah , Aishah Isnin

Sol-gel process has been used for producing high purity and homogenous optical thin films. A high quality, crack free optical thin film and low processing cost are key success factor for optical applications especially in planar waveguides technology. However, film cracks always occur in the silica and silicate base thin films as the thickness of thin film reached above 1m by multi-spinning sol-gel process. Proper handling and consistence conditions was studied using the silica-10% titania sol deposited on silicon wafer substrate. The dry gel silica-10% titania thin film was heat-treated at 680°C using Rapid Thermal Annealing (RTA) furnace. The Rapid Thermal Annealing (RTA) furnace was designed in-house by modifying tube furnace and the required heating rate was set manually. Under controlled deposition conditions in 10K clean room, crack free film ~2micron thick have been succesfully fabricated. However, lack of control in the deposition process can generate dust from excess sol-gel sol during spinning process and then contributes to point of stress in the thin film and cause formation of spider web crack pattern.

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Temperature effect to investigate optical and structural properties of AZO nanostructures for optoelectronics

2021-12-01 , Gherab K. , Al-Douri Y. , Uda Hashim , Khenata R. , Bouhemadou A. , Ameri M.

Spin-coating technique is employed to deposit nanostructured zinc oxide (ZnO) doping aluminium (Al) on p-Si substrate. Atomic forces microscopy (AFM), X-ray diffraction (XRD), ultraviolet–visible (UV–Vis) and scanning electron microscopies (SEM) are utilized to investigate the influence of annealing temperature in the range of 200 to 600°C on the morphological, optical, structural and topographical characteristics of Al NPs-doped ZnO (AZO) nanostructure. The average reflectance is proven by the reflectance spectra to be in the wavelength range of 200–1000 nm, and the absorption spectra provided the optical energy gaps of nanostructured AZO. Crystalline and grain size are correlated with annealing temperature variations, thus providing more homogeneous and covered surface morphology. Our results are nominated for future researches.

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Preliminary studies on antimicrobial activity of extracts from aloe vera leaf, citrus hystrix leaf, zingiber officinale and Sabah snake grass against bacillus subtilis

2018 , Muhammad Nur Aiman Uda , Subash Chandra Bose Gopinath , Nur Hulwani Ibrahim , Mohd Khairul Rabani Hashim , Nuradibah Mohd Amer , Midhat Nabil Ahmad Salimi , Tan Ewe Shen , Ong Yee Fen , Maisara Azad Mat Akhir , Uda Hashim

Herbal plants have several potential antimicrobial activities either as antifungal or antibacterial to fight against the disease and pathogen that attack the plants. The extractions of the Aloe vera leaf, Citrus hystrix leaf, Zingiber officinale rhizome and Sabah snake grass were selected in this study to fight against Bacillus subtilis. B. subtilis is a Gram-positive bacterium, rodshaped and catalase-positive that lives on decayed organic material. It is known as Gram-positive bacteria because of its thick peptidoglycan and would appear purple when subjected to Gram test. This species is commonly found in the upper layers of the soil, in meat or vegetables, in pastry, cooked meat, in bread or poultry products. The extracts of Sabah Snake Grass found to be most effective than A.vera leaf, Z. officinale, and C. hystrix against the B. subtilis.

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Production and characterization of graphene from carbonaceous rice straw by cost-effect extraction

2021-05-01 , Muhammad Nur Aiman Uda , Subash Chandra Bose Gopinath , Uda Hashim , Halim N.H. , Nor Azizah Parmin , Muhammad Nur Afnan Uda , Anbu P.

This paper describes the synthesis of graphene-based activated carbon from carbonaceous rice straw fly ash in an electrical furnace and the subsequent potassium hydroxide extraction. The produced graphene has a proper morphological structure; flakes and a rough surface can be observed. The average size of the graphene was defined as up to 2000 nm and clarification was provided by high-resolution microscopes (FESEM and FETEM). Crystallinity was confirmed by surface area electron diffraction. The chemical bonding from the graphene was clearly observed, with –C=C– and O–H stretching at peaks of 1644 cm−1 and 3435 cm−1, respectively. Impurities in the graphene were found using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The measured size, according to zeta-potential analysis, was 8722.2 ± 25 nm, and the average polydispersity index was 0.576. The stability of the mass reduction was analyzed by a thermogravimetric at 100 Â°C, with a final reduction of ~ 11%.

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A novel parameter effects on optical properties of the LiNbO3 films using sol-gel method

2020-03-25 , Fakhri M.A. , Salim E.T. , Wahid M.H.A. , Salim Z.T. , Uda Hashim

TLN, (LiNbO3) Lithium niobate micro and nano and photonics are prepared and deposited on Silicon substrate using the sol-gel method. All prepared samples are prepared and deposited at the different Substrate temperatures and annealed, at 500 °C. These samples are tested by Ultra-Violet visible (UV-vis), respectively and PL. The presented results were indicated that the values of the optical energy band gaps and values of the optical refractive index are consistent with the presented values of the experimental tests.

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The study of sensing elements parameters optimization for developed biosensor of SARS-CoV-2 detection

2023-04 , Fatin Syakirah Halim , Nor Azizah Parmin , Uda Hashim , Subash Chandra Bose Gopinath , Farrah Aini Dahalan , Iffah Izzati Zakaria , Wei Chern Ang , Nurfareezah Nadhirah Jaapar

New advancements in developing sensitive and selective biosensors have demonstrated outstanding potential for Deoxyribonucleic Acid (DNA biosensors). The detection mode of DNA biosensors primary depends on a particular DNA hybridization that precisely occurs on the surface of the physical transducer that can only be detected using high-performance assays due to slight current changes. The analytical performance (sensitivity) of the DNA biosensor is conclusively rely on the confluence constructing of the sensing surface, which must be optimized. Thus, in this study, the sensing elements of the developed biosensors were optimized for detecting RNA of SARS-CoV-2. This optimization included concentration of nanomaterials (carbon quantum dots), probe density (concentration of DNA probe) and concentration of linker (APTES). It was observed that 0.15 % V/V of concentration CQD, 0.1μM of DNA probe and 36% V/V of APTES were the optimum parameters which provided their maximum response during electrical measurements and increased the sensitivity of the developed biosensor for SARS-CoV-2 detection

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Voltammetric DNA Biosensor for Human Papillomavirus (HPV) Strain 18 Detection

2020-07-09 , Mhd Akhir M.A. , Nor Azizah Parmin , Uda Hashim , Subash Chandra Bose Gopinath , Rejali Z. , Afzan A. , Muhammad Nur Aiman Uda , Muhammad Nur Afnan Uda , Voon Chun Hong

This research was developed to focus on the study of the voltammetric DNA biosensor for the detection of HPV strain 18. In this research, electrical DNA biosensor was expected to detect HPV strain 18 more efficiently by using electrical characterization. In this project, device inspection was conducted to make sure the functional of the gold interdigitated electrode (IDE) by using Scanning Electron Microscope (SEM). 3-Aminopropyl Triethoxysilane (APTES) solution was used for the process of surface modification to form the amine group on the surface of the device to facilitate the attachment of the DNA probe. In this project, synthetic DNA sample and DNA from the saliva of several Biosystems Engineering students were used as the target DNA. The current-voltage (I-V) electrical characterization was conducted to detect the presence of HPV strain 18 in both DNA samples. As the results, perfect alignment between the electrodes on the IDE was detected under SEM. Surface modification of the biosensor successfully conducted which is the covalent bond between APTES and DNA probe increase the electrical. Synthetic DNA shows the presence of HPV strain 18 while there was no HPV strain 18 detected in the DNA from saliva samples.

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