A New Hydrogen Peroxide Biosensor Based on Hrp/Ag Nanowires/Glassy Carbon Electrode

2011 ◽  
Vol 110-116 ◽  
pp. 577-584
Author(s):  
Min Zhang ◽  
Fa Liang Cheng ◽  
Zhi Quan Cai ◽  
Mei Qiong Chen
Keyword(s):  
Fast Response ◽  
Carbon Electrode ◽  
Time Stability ◽  
Enzyme Loading ◽  
X Ray ◽  
H2o2 Detection ◽  
Ag Nanowires ◽  
Long Time ◽  
Optimized Conditions ◽  
Scanning Electron

An amperometric biosensor for H2O2 detection was developed with immobilization of Horseradish Peroxidase (HRP) on Ag nanowires (AgNWs). Ag nanowires (AgNWs) have been prepared by the reductive deposition method and characterized by the scanning electron microscopy (SEM) and the energy dispersive X-ray (EDX). The electrochemical performance of the HRP/AgNWs/GC electrode was investigated by cyclic voltammetry (CV) and chronoamperometry and the use of Ag nanowires led to an efficient enzyme loading, and also provided an increased surface area for sensing the reaction, showing high electrocatalytic activity towards the reduction of H2O2. Under the optimized conditions, the response of the biosensor towards H2O2 was investigated by chronoamperometry. The biosensor exhibited excellent sensitivity (the detection limit was down to 0.005 mM), fast response time (15 sec). Moreover, the biosensor had long-time stability and good reproducibility.

Structural and chemical analysis by transmission and scanning Electron Microscopy of particles found in eyes of cataract patients

1995 ◽  
Vol 53 ◽  
pp. 710-711
Author(s):  
D. Barron
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Medical Center ◽  
The Body ◽  
Cataract Operation ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Long Time ◽  
Time Accumulation ◽  
Scanning Electron

There has been a problem associated with removal of cataracts noted by a number of ophthalmologists, in particular, from Dr. David George at the Madigan Army Medical Center in the state of Washington. Particles were found lodged in the eyes of patients after the cataract operation (see fig. 1). There was serious concern about the origin of the particles. Were they from the ultrasonic surgical head, the surgical blade, or were they from a long time accumulation of the metals found in the body? In an effort to find answers, Dr. George sent samples of the cataract tissue filtered through a Whatman filter to the U.S. Army Center for Health Promotion and Preventive Medicine (CHPPM) for analysis by transmission electron microscopy (TEM), scanning electron microscopy (STEM), x-ray elemental spectral analysis (EDAX), and selected area electron diffraction (SAED). The results were compared with the composition of sample particles from the ultrasonic head and the surgical blade. These particles were filed off the head and blade and secured to a formvar film stretched over a TEM grid. Each set of particles was then analyzed by TEM and a x-ray elemental spectrum was generated.

scholarly journals SEM-EDX Analysis for Surface Aberrations of Neonate's Teeth Influenced by the use of Lithium in Pregnancy

2011 ◽  
Vol 2 (2) ◽  
pp. 105-110
Author(s):  
Shakila Nazir ◽  
Naeem H Naqvi ◽  
A Masood ◽  
N Naema
Keyword(s):  
Electron Microscopy ◽  
Dental Enamel ◽  
Teratogenic Effect ◽  
Congenital Defects ◽  
Developmental Defects ◽  
X Ray ◽  
Long Time ◽  
Developmental Defects Of Enamel ◽  
In Pregnancy ◽  
Scanning Electron

ABSTRACT Objective of the study Developmental defects of enamel may lead to esthetic tribulations. Malformed dental enamel is usually susceptible to caries and sensitivity of teeth. The objective of the present study was to evaluate the distribution of developmental defects affecting the enamel surfaces in the teeth of newborn babies of the mothers, caused by the use of lithium for a long time during pregnancy. Study design/methods The female rabbits were kept on this drug during pregnancy and their offsprings were used for the study. They were sacrificed to obtain their jaws. Teeth were extracted for assessment of the congenital defects developed during intrauterine life. Surface structure was studied by scanning electron microscopy and energy-dispersive X-ray microanalysis (SEM-EDX). Results The results showed that the drug had caused erosions of the incisors and the molars, as compared to the premolars. Conclusion According to the results, incisors and the molars appeared esthetically and functionally compromised teeth. The drug should, therefore, be used by doctor's prescription only, especially during pregnancy, avoiding the teratogenic effect on the dentition of the newborns.

An Improvement on Tracking Resistance of Silicone Rubber Filled with Micro-Wollastonite/Gehlenite Synthesized by Solid-State Reaction

2021 ◽  
Vol 902 ◽  
pp. 107-111
Author(s):  
Pattarabordee Khaigunha ◽  
Tanakorn Wongwuttanasatian
Keyword(s):  
Silicone Rubber ◽  
Room Temperature ◽  
Raw Materials ◽  
Filler Loading ◽  
Test Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Tracking ◽  
Long Time ◽  
Scanning Electron

Enhancement of the room temperature vulcanization silicone rubber (RTV) tracking resistance with various filler loadings of synthesized wollastonite against electrical surface tracking was prepared. The X-ray diffraction (XRD), Scanning electron microscope (SEM), and X-ray fluorescent (XRF) techniques were involved in characterizing the synthesized substances. The test method IEC-60587 standard was employed to evaluate the surface tracking resistance. The results obtained from the XRF technique confirmed that the raw materials could be synthesized for wollastonite, while the XRD and SEM techniques revealed the formation of wollastonite (CaSiO3) associated with gehlenite (Ca2Al2SiO7). Moreover, it was found that the electrical surface tracking resistance of composite insulation takes a long time to track when the filler loading is increased more than 5 phr.

Study on Recovery of Electrical Degradation of ZnO Varistors

2007 ◽  
Vol 350 ◽  
pp. 209-212 ◽  
Author(s):  
Hiroshi Yoshida ◽  
Masayuki Takada ◽  
Shinzo Yoshikado
Keyword(s):  
Crystal Structure ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Ions ◽  
Electrical Degradation ◽  
Long Time ◽  
Zno Varistors ◽  
The Relationship ◽  
Scanning Electron

The relationship between the crystal structure of Bi2O3 and the recovery of the electrical degradation of ZnO varistors was investigated. The evaluation methods used were analysis of the voltage-current (V-I) characteristics, scanning electron microscopy (SEM), energy-dispersion X-ray spectroscopy (EDX), and X-ray diffraction (XRD) measurements. The electrical degradation was estimated by the nonlinearity of the V-I characteristics. A marked recovery of the nonlinearity of the V-I characteristics was observed for a sample having the crystal structure of δ-type Bi2O3. It is speculated that the electrical degradation is markedly recovered for optimum conditions of both the amount and the crystal structure of the added Bi2O3, because, for samples sintered for a long time, the recovery speed is shorter than that for samples sintered for a shorter time. During long-time sintering, the amount of Bi2O3 decreased because of evaporation. No change of the crystal structure of Bi2O3 was observed upon repeated the electrical degradation and the recovery. It is suggested that another mechanism apart from the diffusion of oxygen ions through the grain boundaries of ZnO particles contributes to the electrical degradation and recovery of the nonlinearity of V-I characteristics.

A Novel Nonenzymatic Hydrogen Peroxide Sensor Based on Pd Nanoparticles Modified Electrode

2011 ◽  
Vol 117-119 ◽  
pp. 790-794 ◽  
Author(s):  
Zhen Jing Zhuang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Pd Nanoparticles ◽  
Carbon Electrode ◽  
Deposition Method ◽  
Applied Potential ◽  
Medium Ph ◽  
X Ray ◽  
Electrochemical Deposition Method ◽  
Scanning Electron

Pd nanoparticles have been prepared on the surface of glassy carbon electrode (GCE) by electrochemical deposition method and applied for the nonenzymatic detection of H2O2. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to investigate the as-prepared Pd nanoparticles on the surface of GCE. The electrochemical properties of Pd nanoparticles modified GCE were also characterized by cyclic voltammetry and chronoamperometry. The results showed that Pd nanoparticles modified GCE had a favorable catalytic ability for the reduction of H2O2in PBS medium (pH=7.6). At an applied potential of -0.06 V, the nonenzymatic H2O2sensors produce high and reproducible sensitivity to H2O2with 52.45 μA/mmol۰dm–3. Linear responses were obtained over a concentration range from 0.15 mmol۰dm–3to 18 mmol۰dm–3with a detection limit of 25 μmol۰dm–3(S/N=3). Additionally, it exhibited a rapid response time (within 1s), which was much faster than some nonenzymatic H2O2sensors.

The Methanol Response Sensing Properties Using MWCNT-ZnO Composite

2015 ◽  
Vol 1112 ◽  
pp. 116-119 ◽  
Author(s):  
Ni Luh Wulan Septiani ◽  
Brian Yuliarto ◽  
Muhammad Iqbal ◽  
Suyatman ◽  
Ahmad Nuruddin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Weight Percent ◽  
Fast Response ◽  
Zno Thin Films ◽  
X Ray Diffraction ◽  
Nano Composite ◽  
X Ray ◽  
Sensing Properties ◽  
Best Response ◽  
Scanning Electron

Nano composite MWCNT-ZnO thin films have been synthesized to investigate their methanol sensing properties. MWCNTs have a large surface area, many adsorption site, are sensitive to their chemical environmental, and can be operated at room temperature. While zinc oxide was popular as gas sensor because its easy to fabricate, fast response, easy to control their morphology, and has unique properties depend on their size and shape. In this study, combination of MWCNT and ZnO were made to get their advantages. These nano composites were prepared with weight percent ratio 63:37. MWCNT-ZnO were synthesized by reflux method at 197°C in ethylene glycol. Heat treatment at 300°C were done to obtain powder of nano composite. X-ray diffraction (XRD) and scanning electron microscope were used to investigate the crystal phase and morphology of nano composite. Sensing behavior was investigated at 100°C to 300°C. The best response of 200 ppm methanol occurred at 300°C.

scholarly journals Influence of Synthesis Method on LTA Time-Dependent Stability

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2122 ◽  
Author(s):  
Claudia Belviso ◽  
Antonio Lettino ◽  
Francesco Cavalcante
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
Synthesis Method ◽  
Synthetic Zeolite ◽  
Time Dependent ◽  
Time Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lta Zeolite ◽  
Scanning Electron

Time-stability of LTA zeolite formed by hydrothermal method with or without the action of ultrasonic irradiation was investigated by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The results show that 6 months after the synthesis by hydrothermal process with continuous sonication, LTA evolves into a more stable sodalite, whereas no differences are detected 12 months after LTA synthesis by conventional pre-fused hydrothermal process. These data confirm that using the two approaches, different mechanisms control both zeolite crystallization and time-stability of the newly-formed mineral at solid state. The results are particularly important in the light of the synthetic zeolite application.

Effect of substrates on the growth and properties of LiNbO3 films by the sol-gel method

1994 ◽  
Vol 9 (4) ◽  
pp. 980-985 ◽  
Author(s):  
Nam H. Hur ◽  
Yong K. Park ◽  
Dong H. Won ◽  
Kwangsoo No
Keyword(s):  
Sol Gel ◽  
Epitaxial Films ◽  
Optical Measurements ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Sol Gel Process ◽  
Optimized Conditions ◽  
Scanning Electron

Thin films of LiNbO3 were fabricated on sapphire(012), MgO(OOl), and Si(111) substrates by the sol-gel process. Under optimized conditions, films deposited onto sapphire(012) were epitaxially grown. Preferred orientations, however, were not observed in the films on MgO(001) and Si(111) by x-ray diffraction measurements. Morphology of the epitaxial films on sapphire(012) was examined by scanning electron microscopy, which indicated that the films were smooth and had a pore-free surface. Electrical and optical measurements on the epitaxial films revealed that the properties of the films were very similar to those of the single crystalline LiNbO3, while films deposited onto Si(111) did not show any orientational behaviors. The highest quality films with epitaxy were obtained only on sapphire(012). The remaining substrates appeared to be not suitable for growing epitaxial LiNbO3 films by the sol-gel method.

scholarly journals Investigation of In-service Creep Failures of Aircraft Ti-6Al-4V Bolts

2018 ◽  
Vol 188 ◽  
pp. 04008
Author(s):  
Iordanis Spyroglou ◽  
Kyriakos Kourousis ◽  
Angelos Koutsomichalis
Keyword(s):  
Visual Inspection ◽  
Fracture Morphology ◽  
Sem Analysis ◽  
Void Coalescence ◽  
X Ray ◽  
Service Operation ◽  
Macroscopic Deformation ◽  
Long Time ◽  
Low Temperature Creep ◽  
Scanning Electron

Three Ti-6Al-4V bolts from mid-life jet aircraft failed during service operation. Each of the failed bolts were installed on a landing gear component. Metallurgical failure analysis indicated that the fracture mechanism is low temperature creep, possibly resulting from a sustained tension load over a long time. Visual inspection revealed ductile fracture morphology with no macroscopic deformation or corrosion. For all bolts fracture occurred close to the root at the first pitches of the thread. Scanning Electron Microscope (SEM) analysis revealed dimple morphologies with micro-void coalescence. Energy Dispersive X-Ray (EDX) analysis did not reveal any material deficiency that would have precipitated failure.

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