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Fulltext Exceedingly biocompatible and thin-layered reduced graphene oxide nanosheets using an eco-friendly mushroom extract strategy

Muthoosamy K, Bai RG, Abubakar IB, Sudheer SM, Lim HN, Loh HS, et al.

Int J Nanomedicine, 2015;10:1505-19.
PMID: 25759577 DOI: 10.2147/IJN.S75213

PURPOSE: A simple, one-pot strategy was used to synthesize reduced graphene oxide (RGO) nanosheets by utilizing an easily available over-the-counter medicinal and edible mushroom, Ganoderma lucidum.
METHODS: The mushroom was boiled in hot water to liberate the polysaccharides, the extract of which was then used directly for the reduction of graphene oxide. The abundance of polysaccharides present in the mushroom serves as a good reducing agent. The proposed strategy evades the use of harmful and expensive chemicals and avoids the typical tedious reaction methods.
RESULTS: More importantly, the mushroom extract can be easily separated from the product without generating any residual byproducts and can be reused at least three times with good conversion efficiency (75%). It was readily dispersible in water without the need of ultrasonication or any surfactants; whereas 5 minutes of ultrasonication with various solvents produced RGO which was stable for the tested period of 1 year. Based on electrochemical measurements, the followed method did not jeopardize RGO's electrical conductivity. Moreover, the obtained RGO was highly biocompatible to not only colon (HT-29) and brain (U87MG) cancer cells, but was also viable towards normal cells (MRC-5).
CONCLUSION: Besides being eco-friendly, this mushroom based approach is easily scalable and demonstrates remarkable RGO stability and biocompatibility, even without any form of functionalization.

Matched MeSH terms: Oxides/chemistry*
Fulltext Effects of gate stack structural and process defectivity on high-k dielectric dependence of NBTI reliability in 32 nm technology node PMOSFETs

Hussin H, Soin N, Bukhori MF, Hatta SW, Wahab YA

ScientificWorldJournal, 2014;2014:490829.
PMID: 25221784 DOI: 10.1155/2014/490829

We present a simulation study on negative bias temperature instability (NBTI) induced hole trapping in E' center defects, which leads to depassivation of interface trap precursor in different geometrical structures of high-k PMOSFET gate stacks using the two-stage NBTI model. The resulting degradation is characterized based on the time evolution of the interface and hole trap densities, as well as the resulting threshold voltage shift. By varying the physical thicknesses of the interface silicon dioxide (SiO2) and hafnium oxide (HfO2) layers, we investigate how the variation in thickness affects hole trapping/detrapping at different stress temperatures. The results suggest that the degradations are highly dependent on the physical gate stack parameters for a given stress voltage and temperature. The degradation is more pronounced by 5% when the thicknesses of HfO2 are increased but is reduced by 11% when the SiO2 interface layer thickness is increased during lower stress voltage. However, at higher stress voltage, greater degradation is observed for a thicker SiO2 interface layer. In addition, the existence of different stress temperatures at which the degradation behavior differs implies that the hole trapping/detrapping event is thermally activated.

Matched MeSH terms: Oxides
Fulltext Gate length variation effect on performance of gate-first self-aligned In₀.₅₃Ga₀.₄₇As MOSFET

Mohd Razip Wee MF, Dehzangi A, Bollaert S, Wichmann N, Majlis BY

PLoS One, 2013;8(12):e82731.
PMID: 24367548 DOI: 10.1371/journal.pone.0082731

A multi-gate n-type In₀.₅₃Ga₀.₄₇As MOSFET is fabricated using gate-first self-aligned method and air-bridge technology. The devices with different gate lengths were fabricated with the Al2O3 oxide layer with the thickness of 8 nm. In this letter, impact of gate length variation on device parameter such as threshold voltage, high and low voltage transconductance, subthreshold swing and off current are investigated at room temperature. Scaling the gate length revealed good enhancement in all investigated parameters but the negative shift in threshold voltage was observed for shorter gate lengths. The high drain current of 1.13 A/mm and maximum extrinsic transconductance of 678 mS/mm with the field effect mobility of 364 cm(2)/Vs are achieved for the gate length and width of 0.2 µm and 30 µm, respectively. The source/drain overlap length for the device is approximately extracted about 51 nm with the leakage current in order of 10(-8) A. The results of RF measurement for cut-off and maximum oscillation frequency for devices with different gate lengths are compared.

Matched MeSH terms: Oxides
Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET

Tan ML, Lentaris G, Amaratunga Aj G

Nanoscale Res Lett, 2012;7(1):467.
PMID: 22901374

The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio (Ion/Ioff), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency.

Matched MeSH terms: Oxides
Fulltext Synergistic Effects of Pr6O11 and Co3O4 on Electrical and Microstructure Features of ZnO-BaTiO3 Varistor Ceramics

Shaifudin MS, Ghazali MSM, Kamaruzzaman WMIWM, Wan Abdullah WR, Kassim S, Ismail NQA, et al.

Materials (Basel), 2021 Feb 03;14(4).
PMID: 33546094 DOI: 10.3390/ma14040702

This paper investigated the effects of Pr6O11 and Co3O4 on the electrical properties of ZnO-BaTiO3 varistor ceramics. The Pr6O11 doping has a notable influence on the characteristics of the nonlinear coefficient, varistor voltage, and leakage current where the values varied from 2.29 to 2.69, 12.36 to 68.36 V/mm and 599.33 to 548.16 µA/cm2, respectively. The nonlinear varistor coefficient of 5.50 to 7.15 and the varistor voltage of 7.38 to 8.10 V/mm was also influenced by the use of Co3O4 as a dopant. When the amount of Co3O4 was above 0.5 wt.%, the leakage current increased from 202.41 to 302.71 μA/cm2. The varistor ceramics with 1.5 wt.% Pr6O11 shows good nonlinear electrical performance at higher breakdown voltage and reduced the leakage current of the ceramic materials. Besides, the varistor sample that was doped with 0.5 wt.% Co3O4 was able to enhance the nonlinear electrical properties at low breakdown voltage with a smaller value of leakage current.

Matched MeSH terms: Oxides
Aerobic oxidation of 5-hydroxymethylfurfural into 2,5-diformylfuran using manganese dioxide with different crystal structures: A comparative study

Lin KA, Oh WD, Zheng MW, Kwon E, Lee J, Lin JY, et al.

J Colloid Interface Sci, 2021 Jun 15;592:416-429.
PMID: 33691223 DOI: 10.1016/j.jcis.2021.02.030

Aerobic oxidation of 5-Hydroxymethylfurfural (HMF) to 2,5-Diformylfuran (DFF) using O2 gas represents a sustainable approach for valorization of lignocellulosic compounds. As manganese dioxide (MnO2) is validated as a useful oxidation catalyst and many crystalline forms of MnO2 exist, it is critical to explore how the crystalline structures of MnO2 influence their physical/chemical properties, which, in turn, determine catalytic activities of MnO2 crystals for HMF oxidation to DFF. In particular, six MnO2 crystals, α-MnO2, β-MnO2, γ-MnO2, δ-MnO2, ε-MnO2, and λ-MnO2 are prepared and investigated for their catalytic activities for HMF oxidation to DFF. With different morphologies and crystalline structures, these MnO2 crystals possess very distinct surficial chemistry, redox capabilities, and textural properties, making these MnO2 exhibit different catalytic activities towards HMF conversion. Especially, β-MnO2 can produce much higher DFF per surface area than other MnO2 crystals. β-MnO2 could achieve the highest CHMF = 99% and YDFF = 97%, which are much higher than the reported values in literature, possibly because the surficial reactivity of β-MnO2 appears to be highest in comparison to other MnO2 crystals. Especially, β-MnO2 could exhibit YDFF > 90% over 5 cycles of reusability test, and maintain its crystalline structure, revealing its advantageous feature for aerobic oxidation of HMF to DFF. Through this study, the relationship between morphology, surface chemistry, and catalytic activity of MnO2 with different crystal forms is elucidated for providing scientific insights into design, application and development of MnO2-based materials for aerobic oxidation of bio-derived molecules to value-added products.

Matched MeSH terms: Oxides
Fulltext Analysis of glass fracture pattern on soda lime and tempered glass caused by shotgun bullet impact

Dahshaini Nadarajan, Sharifah Mastura Syed Mohd Daud, Nadiah Syariani Md Shariff

Malaysian Journal of Medicine and Health Sciences, 2020;16(101):131-135.
MyJurnal

Introduction: Broken glass exhibits unique fracture patterns depend upon the nature of the impact. The fracture patterns provide information like point and angle of impact, direction of force and sequence of firing. Recent studies have shown that the use of shotgun in Malaysia is increasing, yet, the relationship existing among the fracture pattern and the projectile impact factors are not well documented. The objective was to analyse the fracture characteristics on different glass types of variable thickness and distance made by shotgun ammunition. Methods: Soda lime and tempered glass panel with dimension of 12’x 12’ with 3 or 4 mm thickness were shot from various distances of 4, 6 and 8 m from the muzzle end of the shotgun. Samples were analysed under fixed parameters and observations were recorded. Results: It is found that the bullet hole diameter of 4 mm tempered glass were larger compared to 4 mm soda lime glass ranged from 14.33 to 24.17 cm as distance increased. Tempered glass surface also exhibited dicing fragments unlike soda lime glass where only radial fracture patterns are evident. This can be attributed to high inherent strength and ductility that makes the tempered glass remarkably resistant to external force. Conclusion: The findings from this study can lead to distinguish the type of glass through examination of fracture patterns, whether it is soda lime silica or tempered glass. The type of glass and the source of impact can be determined using the fragments, no reconstruction necessary.

Matched MeSH terms: Oxides
Facile Fabrication of Plasmonic Enhanced Noble-Metal-Decorated ZnO Nanowire Arrays for Dye-Sensitized Solar Cells

Tan WK, Muto H, Ito T, Kawamura G, Lockman Z, Matsuda A

J Nanosci Nanotechnol, 2020 Jan 01;20(1):359-366.
PMID: 31383179 DOI: 10.1166/jnn.2020.17223

Novel decoration of high aspect ratio zinc oxide nanowires (ZnO NWs) with noble metals such as Ag and Au nanoparticles (NPs) was demonstrated in this work. A facile method of chemical deposition with good controllability, as well as good homogeneity would be a huge advantage towards large scale fabrication. The highlight of this work is the feasibility of multiple component decoration such as a hybrid (co-exist) Ag-Au NPs decorated ZnO NWs formation that could be beneficial towards the development of nanoarchitectured materials with the most desired properties. The local surface plasmon effect (LSPR) of Ag and Au NPs were confirmed using extinction spectra and significant photoelectrochemical conversion efficiency (PCE) enhancement of dye-sensitized solar cells (DSSCs) was achieved. The Ag-NPs and hybrid Ag-Au NPs decorated ZnO NWs marked an impressive 125 and 240% efficiency improvement against pure ZnO NWs. The improved dye light extinction resulted from the LSPR effect that had enabled greater electron generation leading to improved PCE. As the complex design of oxides' nanoarchitectures have reached a point of saturation, this novel method would enable further enhancement in their photoelectrochemical properties through decoration with noble metals via a simple chemical deposition route.

Matched MeSH terms: Oxides
Nanowire dimensions effect on ON/OFF current ratio and sub-threshold slope in silicon nanowire transistors

Hashim Y, Sidek O

J Nanosci Nanotechnol, 2012 Sep;12(9):7101-4.
PMID: 23035439

This paper shows the effect of the dimensions of nanowires on threshold voltage, ON/OFF current ratio, and sub-threshold slope. These parameters are critical factors of the characteristics of silicon nanowire transistors. The MuGFET simulation tool was used to investigate the characteristics of a transistor. Current-voltage characteristics with different dimensions were simulated. Results show that long nanowires with low diameter and oxide thickness tend to have the best transistor characteristics.

Matched MeSH terms: Oxides
Fulltext Characterization and phase evolution of cordierite based glass synthesis from pure oxide and minerals

Banjuraizah Johar, Hasmaliza Mohamad, Zainal Arifin Ahmad

Journal of Nuclear and Related Technologies, 2009;2009(1):237-246.
MyJurnal

α Cordierite is very important phase in MgO-Al2O3-SiO2 system because of their very outstanding thermal, chemical and electrical properties. In this presents study nonstoichiometry cordierite (MgO:Al2O3:SiO2 = 3:1.5:5) using 2 different initial raw materials ( (i)mixture of pure oxide, and ii) mainly mixture of minerals) were fabricated and compared in terms of phase transformation and physical properties. Cordierite was prepared by glass method at low melting temperature (1350°C). Low melting temperature has resulted in partly crystalline glass which has possesses higher hardness, required longer milling time and result in contamination from grinding media. However, α-cordierite has successfully crystallized and fully densified at 850°C/2h. Activation energy for densification was investigated from thermal expansion coefficient (TCE) results. Other properties that were discussed included thermal properties using DTA/TGA.

Matched MeSH terms: Oxides
Design of a Sub-Picosecond Jitter with Adjustable-Range CMOS Delay-Locked Loop for High-Speed and Low-Power Applications

Abdulrazzaq BI, Ibrahim OJ, Kawahito S, Sidek RM, Shafie S, Yunus NA, et al.

Sensors (Basel), 2016 Sep 28;16(10).
PMID: 27690040

A Delay-Locked Loop (DLL) with a modified charge pump circuit is proposed for generating high-resolution linear delay steps with sub-picosecond jitter performance and adjustable delay range. The small-signal model of the modified charge pump circuit is analyzed to bring forth the relationship between the DLL's internal control voltage and output time delay. Circuit post-layout simulation shows that a 0.97 ps delay step within a 69 ps delay range with 0.26 ps Root-Mean Square (RMS) jitter performance is achievable using a standard 0.13 µm Complementary Metal-Oxide Semiconductor (CMOS) process. The post-layout simulation results show that the power consumption of the proposed DLL architecture's circuit is 0.1 mW when the DLL is operated at 2 GHz.

Matched MeSH terms: Oxides
Draft Genome Sequence of the Sulfate-Reducing Bacterium Desulfotomaculum copahuensis Strain CINDEFI1 Isolated from the Geothermal Copahue System, Neuquén, Argentina

Willis Poratti G, Yaakop AS, Chan CS, Urbieta MS, Chan KG, Ee R, et al.

Genome Announc, 2016;4(4).
PMID: 27540078 DOI: 10.1128/genomeA.00870-16

Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment.

Matched MeSH terms: Sulfur Oxides
Fulltext Are patients satisfied with hospital food?

Teng, Sang-Chong, Esah Bahaman, Tang, Wen-Yen

Malaysian Journal of Public Health Medicine, 2003;3(1):52-56.
MyJurnal

Although only 6.3% of the 221 respondents in this crass-sectional study stated outright that the hospital food served to them was not good, a high proportion of respondents ( 62.0%) supplemented ltaspimlfoad with outside food. When the reasons for supplementation were considered, it is likely that 53.8% ( $5.5%; 95% CI ) of the patients in this study were dissatisfied with hospimlfoudfar some reasons or when particularly with regards t0 variety, attractiveness and sewing lime. The pl‘0]701’l‘i011 of respondents wha were dissatisfied with hospital faud was significantly higher (p

Matched MeSH terms: Oxides
Fulltext Characterization of zirconium sulfate supported on mesoporous molecular sieve HMS catalyst using XRD, XRF and XPS techniques

Joon, Ching Juana, Mohd Ambar Yarmob, Zhangc, Jingchang

Journal of Nuclear and Related Technologies, 2009;2009(1):297-305.
MyJurnal

New solid acid catalyst consisting of zirconium sulfate (ZS) supported on a pure-HMS hexagonal mesoporous material (HMS) have been prepared and characterized. This heterogeneous catalyst is able to make a contribution to the field of acid catalyst involving bulky organic molecules. XRD analysis shows that ZS is intact after impregnated on HMS surface and formed finely dispersed species. No ZS crystal phase was developed even at ZS loadings as high as 40 wt %. The occurrence of chemical interaction between ZS and HMS was observed by XPS analysis. Further, XRF results demonstrated that there is no leaching of ZS elements after impregnation. This study shows that ZS can be impregnated on HMS and would be a promising solid acid catalyst for acid-type reactions espcially invovling bulky organic molecuels.

Matched MeSH terms: Sulfur Oxides
Fulltext Intercorrelation of surface free energy and anode capacity of alumnium alloy anodes

Muhamad Daud, Sarimah Mahat, Mohd Sharif Sattar

Journal of Nuclear and Related Technologies, 2006;2006(1):19-24.
MyJurnal

Surface free energies have been evaluated from Young’s moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ~1.47%Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ≈ 0.08mA/cm 2 , current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surface free energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum.

Matched MeSH terms: Oxides
Fulltext The effects of CR2O3 addition on microstructure and fracture toughness of ZTA ceramic composite

Ahmad Zahirani Ahmad Azhar, Hasmaliza Mohamed, Mani Maran Ratnam, Zainal Arifin Ahmad

Journal of Nuclear and Related Technologies, 2013;2013(2):9-15.
MyJurnal

The microstructure and mechanical properties of ceramic composites produced from alumina, yttria stabilized zirconia and chromia oxide system was investigated. The Cr2O3 weight percent was varied from 0 wt% to 1.0 wt%. Each batch of composition was mixed, uniaxially pressed to 13mm diameter and sintered at 1600 ◦C for 4 h in pressureless conditions. Studies on the effects of the sample microstructures on their mechanical and physical properties such as fracture toughness and bulk density were carried out. Results show that an addition of 0.6 wt% of Cr2O3 produces the best mechanical properties. Furthermore, microstructural observations show that the Al2O3 grain size is significantly dependent on the amount of Cr2O3 additives used. Maximum value obtained with 0.6 wt % Cr2O3 for the fracture toughness is 5.36 MPa.m1/2.

Matched MeSH terms: Oxides
Fulltext An overview of bacterial concrete on concrete durability in aggressive environment

Irwan, J.M., Teddy, T.

Pertanika Journal of Science & Technology, 2017;25(105):259-264.
MyJurnal

Concrete durability determines service life of structures. It can though, be weakened by aggressive environmental conditions. For instance, bio-corrosion process is due to the presence and activity of microorganisms which produce sulphuric acid to form sulphate deterioration of concrete materials. The problems related to durability and repair systems are due to lack of suitable concrete materials. The use bacteria for concrete repairing and plugging of pores and cracking in concrete has been recently explored. Previous studies had proved the possibility of using specific bacteria via bio concrete as a sustainable method for improving concrete properties. Thus, lack of information on the application of bio concrete exposed to extreme condition was the motivation for this research.

Matched MeSH terms: Sulfur Oxides
Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

Khairudin NF, Sukri MFF, Khavarian M, Mohamed AR

Beilstein J Nanotechnol, 2018;9:1162-1183.
PMID: 29719767 DOI: 10.3762/bjnano.9.108

Dry reforming of methane (DRM) is one of the more promising methods for syngas (synthetic gas) production and co-utilization of methane and carbon dioxide, which are the main greenhouse gases. Magnesium is commonly applied in a Ni-based catalyst in DRM to improve catalyst performance and inhibit carbon deposition. The aim of this review is to gain better insight into recent developments on the use of Mg as a support or promoter for DRM catalysts. Its high basicity and high thermal stability make Mg suitable for introduction into the highly endothermic reaction of DRM. The introduction of Mg as a support or promoter for Ni-based catalysts allows for good metal dispersion on the catalyst surface, which consequently facilitates high catalytic activity and low catalyst deactivation. The mechanism of DRM and carbon formation and reduction are reviewed. This work further explores how different constraints, such as the synthesis method, metal loading, pretreatment, and operating conditions, influence the dry reforming reactions and product yields. In this review, different strategies for enhancing catalytic activity and the effect of metal dispersion on Mg-containing oxide catalysts are highlighted.

Matched MeSH terms: Oxides
Fulltext Bandgap tuning of mixed organic cation utilizing chemical vapor deposition process

Kim J, Kim HP, Teridi MA, Yusoff AR, Jang J

Sci Rep, 2016 11 22;6:37378.
PMID: 27874026 DOI: 10.1038/srep37378

Bandgap tuning of a mixed organic cation perovskite is demonstrated via chemical vapor deposition process. The optical and electrical properties of the mixed organic cation perovskite can be manipulated by varying the growth time. A slight shift of the absorption band to shorter wavelengths is demonstrated with increasing growth time, which results in the increment of the current density. Hence, based on the optimized growth time, our device exhibits an efficiency of 15.86% with negligible current hysteresis.

Matched MeSH terms: Oxides
Fulltext Metal oxide based optical fiber for methane gas detection

Nor Akmar Mohd Yahya, Siti Azlida Ibrahim, Norizah Abdul Rahman, Mohd Adzir Mahdi, Mohd Hanif Yaacob

The Pertanika Journal of Scholarly Research Reviews, 2017;3(2):97-101.
MyJurnal

Semiconductor metal oxide (SMO) as a sensing layer for gas detection has been widely used. Many researches have been performed to enhance the sensing performance including its sensitivity, reliability and selectivity. Electrical sensors that use resistivity as an indicator of its sensing are popular and well established. However, the optical based sensor is still much to explore in detecting gas. By integrating it with SMO, the sensor offers good alternative to overcome some drawbacks from electrical sensors.

Matched MeSH terms: Oxides

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