MyMedR

Displaying publications 81 - 88 of 88 in total

Abstract:

Sort:

Fulltext Ultrathin Assembles of Porous Array for Enhanced H2 Evolution

Islam A, Hwa Teo S, Awual MR, Taufiq-Yap YH

Sci Rep, 2020 Feb 11;10(1):2324.
PMID: 32047187 DOI: 10.1038/s41598-020-59325-4

Since the complexity of photocatalyst synthesis process and high cost of noble cocatalyst leftovers a major hurdle to producing hydrogen (H2) from water, a noble metal-free Ni-Si/MgO photocatalyst was realized for the first time to generate H2 effectively under illumination with visible light. The catalyst was produced by means of simple one-pot solid reaction using self-designed metal reactor. The physiochemical properties of photocatalyst were identified by XRD, FESEM, HRTEM, EDX, UV-visible, XPS, GC and PL. The photocatalytic activities of Ni-Si/MgO photocatalyst at different nickel concentrations were evaluated without adjusting pH, applied voltage, sacrificial agent or electron donor. The ultrathin-nanosheet with hierarchically porous structure of catalyst was found to exhibit higher photocatalytic H2 production than hexagonal nanorods structured catalyst, which suggests that the randomly branched nanosheets are more active surface to increase the light-harvesting efficiency due to its short electron diffusion path. The catalyst exhibited remarkable performance reaching up to 714 µmolh-1 which is higher among the predominant semiconductor catalyst. The results demonstrated that the photocatalytic reaction irradiated under visible light illumination through the production of hydrogen and hydroxyl radicals on metals. The outcome indicates an important step forward one-pot facile approach to prepare noble ultrathin photocatalyst for hydrogen production from water.

Matched MeSH terms: Semiconductors
Relation between sick leave and selected exposure variables among women semiconductor workers in Malaysia

Chee HL, Rampal KG

Occup Environ Med, 2003 Apr;60(4):262-70.
PMID: 12660374

To determine the relation between sick leave and selected exposure variables among women semiconductor workers.

Matched MeSH terms: Semiconductors*
Fulltext The prevalence of musculoskeletal problems and risk factors among women assembly workers in the semiconductor industry

Chandrasakaran A, Chee HL, Rampal KG, Tan GLE

Med J Malaysia, 2003 Dec;58(5):657-66.
PMID: 15190650

A cross-sectional study to determine work-related musculoskeletal problems and ergonomic risk factors was conducted among 529 women semiconductor workers. Overall, 83.4% had musculoskeletal symptoms in the last one year. Pain in the back (57.8%), lower leg (48.4%) and shoulder (44.8%) were the three most common musculoskeletal problems. Significant associations were found between prolonged standing and upper and lower leg pain, between prolonged sitting and neck and shoulder pain and between prolonged bending and shoulder arm, back and upper leg pain. The study therefore showed a clear association between work-related musculoskeletal pain and prolonged hours spent in particular postures and movements.

Matched MeSH terms: Semiconductors
Fulltext Photochemical Synthesis of Nanosheet Tin Di/Sulfide with Sunlight Response on Water Pollutant Degradation

Matmin J, Jalani MA, Osman H, Omar Q, Ab'lah N, Elong K, et al.

Nanomaterials (Basel), 2019 Feb 14;9(2).
PMID: 30769911 DOI: 10.3390/nano9020264

The photochemical synthesis of two-dimensional (2D) nanostructured from semiconductor materials is unique and challenging. We report, for the first time, the photochemical synthesis of 2D tin di/sulfide (PS-SnS₂-x, x = 0 or 1) from thioacetamide (TAA) and tin (IV) chloride in an aqueous system. The synthesized PS-SnS₂-x were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), a particle size distribution analyzer, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), thermal analysis, UV⁻Vis diffuse reflectance spectroscopy (DR UV⁻Vis), and photoluminescence (PL) spectroscopy. In this study, the PS-SnS₂-x showed hexagonally closed-packed crystals having nanosheets morphology with the average size of 870 nm. Furthermore, the nanosheets PS-SnS₂-x demonstrated reusable photo-degradation of methylene blue (MB) dye as a water pollutant, owing to the stable electronic conducting properties with estimated bandgap (Eg) at ~2.5 eV. Importantly, the study provides a green protocol by using photochemical synthesis to produce 2D nanosheets of semiconductor materials showing photo-degradation activity under sunlight response.

Matched MeSH terms: Semiconductors
Fulltext Light-Addressable Potentiometric Sensors Using ZnO Nanorods as the Sensor Substrate for Bioanalytical Applications

Tu Y, Ahmad N, Briscoe J, Zhang DW, Krause S

Anal Chem, 2018 07 17;90(14):8708-8715.
PMID: 29932632 DOI: 10.1021/acs.analchem.8b02244

Light-addressable potentiometric sensors (LAPS) are of great interest in bioimaging applications such as the monitoring of concentrations in microfluidic channels or the investigation of metabolic and signaling events in living cells. By measuring the photocurrents at electrolyte-insulator-semiconductor (EIS) and electrolyte-semiconductor structures, LAPS can produce spatiotemporal images of chemical or biological analytes, electrical potentials and impedance. However, its commercial applications are often restricted by their limited AC photocurrents and resolution of LAPS images. Herein, for the first time, the use of 1D semiconducting oxides in the form of ZnO nanorods for LAPS imaging is explored to solve this issue. A significantly increased AC photocurrent with enhanced image resolution has been achieved based on ZnO nanorods, with a photocurrent of 45.7 ± 0.1 nA at a light intensity of 0.05 mW, a lateral resolution as low as 3.0 μm as demonstrated by images of a PMMA dot on ZnO nanorods and a pH sensitivity of 53 mV/pH. The suitability of the device for bioanalysis and bioimaging was demonstrated by monitoring the degradation of a thin poly(ester amide) film with the enzyme α-chymotrypsin using LAPS. This simple and robust route to fabricate LAPS substrates with excellent performance would provide tremendous opportunities for bioimaging.

Matched MeSH terms: Semiconductors
Fulltext Incoming Work-In-Progress Prediction in Semiconductor Fabrication Foundry Using Long Short-Term Memory

Tin TC, Chiew KL, Phang SC, Sze SN, Tan PS

Comput Intell Neurosci, 2019;2019:8729367.
PMID: 30719036 DOI: 10.1155/2019/8729367

Preventive maintenance activities require a tool to be offline for long hour in order to perform the prescribed maintenance activities. Although preventive maintenance is crucial to ensure operational reliability and efficiency of the tool, long hour of preventive maintenance activities increases the cycle time of the semiconductor fabrication foundry (Fab). Therefore, this activity is usually performed when the incoming Work-in-Progress to the equipment is forecasted to be low. The current statistical forecasting approach has low accuracy because it lacks the ability to capture the time-dependent behavior of the Work-in-Progress. In this paper, we present a forecasting model that utilizes machine learning method to forecast the incoming Work-In-Progress. Specifically, our proposed model uses LSTM to forecast multistep ahead incoming Work-in-Progress prediction to an equipment group. The proposed model's prediction results were compared with the results of the current statistical forecasting method of the Fab. The experimental results demonstrated that the proposed model performed better than the statistical forecasting method in both hit rate and Pearson's correlation coefficient, r.

Matched MeSH terms: Semiconductors
In vitro anti-breast cancer studies of LED red light therapy through autophagy

Yang KL, Khoo BY, Ong MT, Yoong ICK, Sreeramanan S

Breast Cancer, 2021 Jan;28(1):60-66.
PMID: 32654094 DOI: 10.1007/s12282-020-01128-6

LED red light has been reported to have many health benefits. The present study was conducted to characterise anti-proliferation properties of four LED red light wavelengths (615, 630, 660 and 730 nm) against non-triple negative (MCF-7) and triple negative (MDA-MB-231) breast cancer-origin cell lines. It has been shown by MTT assay that at 24 h post-exposure time point, only LED red light with wavelength 660 nm possessed anti-proliferative effects against both cell lines with 40% reduction of cell viability. The morphology of LED 660 nm irradiated cells was found flatten with enlarged cell size, typical characteristic of cell senescent. Indications of autophagy activities following the irradiation have been provided by acridine orange staining, showing high presence of acidic vesicle organelles (AVOs). In addition, high LC3-II/LC3-I to LC3 ratio has been observed qualitatively in Western blot analysis indicating an increase number of autophagosomes formation in LED 660 nm irradiated cells compared to control cells. Electron dense bodies observed in these cells under TEM micrographs provided additional support to the above observations, leading to the conclusion that LED 660 nm irradiation promoted anti-proliferative activities through autophagy in breast cancer-origin cells. These findings have suggested that LED 660 nm might be developed and be employed as an alternative cancer treatment method in future.

Matched MeSH terms: Semiconductors
Evaluation of rectal dose discrepancies between planned and in vivo dosimetry using MOSkin detector and PTW 9112 semiconductor probe during 60Co HDR CT-based intracavitary cervix brachytherapy

Jamalludin Z, Jong WL, Malik RA, Rosenfeld AB, Ung NM

Phys Med, 2020 Jan;69:52-60.
PMID: 31830631 DOI: 10.1016/j.ejmp.2019.11.025

PURPOSE: Dose to the rectum during brachytherapy treatment may differ from an approved treatment plan which can be quantified with in vivo dosimetry (IVD). This study compares the planned with in vivo doses measured with MOSkin and PTW 9112 rectal probe in patients undergoing CT based HDR cervical brachytherapy with Co-60 source.
METHODS: Dose measurement of a standard pear-shaped plan carried out in phantom to verify the MOSkin dose measurement accuracy. With MOSkin attached to the third diode, RP3 of the PTW 9112, both detectors were inserted into patients' rectum. The RP3 and MOSkin measured doses in 18 sessions as well as the maximum measured doses from PTW 9112, RPmax in 48 sessions were compared to the planned doses.
RESULTS: Percentage dose differences ΔD (%) in phantom study for two MOSkin found to be 2.22 ± 0.07% and 2.5 ± 0.07%. IVD of 18 sessions resulted in ΔD(%) of -16.3% to 14.9% with MOSkin and ΔD(%) of -35.7% to -2.1% with RP3. In 48 sessions, RPmax recorded ΔD(%) of -37.1% to 11.0%. MOSkin_measured doses were higher in 44.4% (8/18) sessions, while RP3_measured were lower than planned doses in all sessions. RPmax_measured were lower in 87.5% of applications (42/47).
CONCLUSIONS: The delivered doses proven to deviate from planned doses due to unavoidable shift between imaging and treatment as measured with MOSkin and PTW 9112 detectors. The integration of MOSkin on commercial PTW 9112 surface found to be feasible for rectal dose IVD during cervical HDR ICBT.

Matched MeSH terms: Semiconductors