scholarly journals Highly Sensitive Biosensors Based on Oxidase-Amplified Reaction Induced by Reducing Agents.

1999 ◽  
pp. 431-440
Author(s):  
Yasushi HASEBE ◽  
Shunichi UCHIYAMA
Keyword(s):  
Reducing Agents ◽  
Highly Sensitive

scholarly journals The technology of the selective precipitation of arsenic from solutions for its detection and isolation

2021 ◽  
Author(s):  
Avak Avakyan
Keyword(s):  
Water Solution ◽  
Reducing Agents ◽  
Selective Precipitation ◽  
Qualitative Reaction ◽  
Highly Sensitive ◽  
Amorphous Precipitate

This is a technology of the selective precipitation of (AsO4)3− from solutions as the Fe3+ hydroxoarsenate using the FeCl3, NaHCO3 and CH3CO2H. This can be used as a qualitative reaction for arsenic. The dissolving of the Fe3+ and Ag+ arsenates in CH3CO2H in the presence of the CH3CO2Na is discovered. The Fe3+ acetate is stable in water solution without other reagents (it was discovered); and it is stable in CH3CO2H solutions. The arsenic can be isolated using the reactions: Fe3+ hydroxoarsenate + reducing agents, example: Ca(H2PO2)2, as the dark amorphous precipitate (like soot). Then it can be sublimated. This is a safe easy reliable highly sensitive alternative to the Marsh test.

Fabrication of highly sensitive ethanol sensor based on doped nanostructure materials using tiny chips

RSC Advances ◽  
2015 ◽  
Vol 5 (78) ◽  
pp. 63252-63263 ◽  
Author(s):  
Mohammed M. Rahman ◽  
Abdullah M. Asiri
Keyword(s):  
Chemical Process ◽  
Reducing Agents ◽  
Ethanol Sensor ◽  
Medium Ph ◽  
High Ph ◽  
Nanostructure Materials ◽  
Highly Sensitive ◽  
Wet Chemical

Doped CuO–Fe2O3 nanocubes (NCs) are prepared via a facile wet-chemical process using active reactant precursors with reducing agents in high pH medium (pH > 10).

Gold Nanoparticle Enlargement Coupled with Fluorescence Decrease for Highly Sensitive Detection of Analytes

2011 ◽  
Vol 1301 ◽  
Author(s):  
Seong Yoon Lim ◽  
Jae Hong Kim ◽  
Joon Seok Lee ◽  
Chan Beum Park
Keyword(s):  
Gold Nanoparticles ◽  
Enzymatic Reaction ◽  
Optical Biosensor ◽  
Reducing Agents ◽  
Sensitive Detection ◽  
Detection Methods ◽  
Fluorescent Substrate ◽  
Reaction Solution ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

ABSTRACTWe present a versatile and facile route for highly sensitive detection of analytes through coupling the enlargement of gold nanoparticles (Au NPs) with fluorescence decrease. The fluorescence intensity of dye molecules (e.g., fluorescein or rhodamine B) significantly decreased with the increasing concentration of reducing agents, such as hydrogen peroxide and hydroquinone. The sensitivity for the detection of reducing agents was much higher than other detection methods based on the absorbance measurement of enlarged gold nanoparticles or quantum dot-enzyme hybridization. We could successfully detect acetylthiocholine with the detection limit of several nM orders, using an enzymatic reaction by acetylcholinesterase, a key route for the detection of toxic organophosphate compounds. The fluorescence decreasing approach described in this work requires only a simple addition of fluorescence dye to the reaction solution without any chemical modification. The strategy of fluorescence decrease coupled with nanoparticle growth will be applied on the fluorescent substrate to develop detection templates for highly sensitive optical biosensor.

scholarly journals Microencapsulation of Riboflavin (Vitamine B2) using Alginate and Chitosan : Effect of Surfactant Span 80 upon Microcapsule Diameter

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
YC. Danarto ◽  
Rochmadi Rochmadi ◽  
Budhijanto Budhijanto
Keyword(s):  
Sodium Alginate ◽  
Environmental Influences ◽  
Reducing Agents ◽  
Vitamin B2 ◽  
Human Metabolism ◽  
Paraffin Oil ◽  
Highly Sensitive ◽  
Span 80

<p>Riboflavin (vitamin B2) plays an important role in the growth and maintenance of human metabolism. Riboflavin is the highly sensitive and unstable to environmental influences such as light, reducing agents and pH. Riboflavin is protected by forming it into microcapsules with sodium alginate as a matrix and coated with chitosan reinforced with glutraldehid crosslinking. This study aims to study the process of microencapsulation of riboflavin with sodium alginate and chitosan and is emphasized to study the effect surfactant span 80 upon the size of the microcapsules formed. Based on microcapsule size and its distribution,  it  can  be  concluded  that  more  span  80  added  to  paraffin  oil  will  reduce  the  size  of microcapsule that is formed</p>

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Fluorescence ratio imaging of dynamic intracellular ionic signals

1988 ◽  
Vol 46 ◽  
pp. 42-43
Author(s):  
R. Y. Tsien ◽  
A. Minta ◽  
M. Poenie ◽  
J.P.Y. Kao ◽  
A. Harootunian
Keyword(s):  
Binding Sites ◽  
Living Cells ◽  
Molecular Engineering ◽  
Ph Indicators ◽  
Highly Sensitive ◽  
Fluorescence Ratio Imaging ◽  
Ratio Imaging ◽  
Technical Advances ◽  
Indicator Dyes ◽  
Fluorescein Dyes

Recent technical advances now enable the continuous imaging of important ionic signals inside individual living cells with micron spatial resolution and subsecond time resolution. This methodology relies on the molecular engineering of indicator dyes whose fluorescence is strong and highly sensitive to ions such as Ca2+, H+, or Na+, or Mg2+. The Ca2+ indicators, exemplified by fura-2 and indo-1, derive their high affinity (Kd near 200 nM) and selectivity for Ca2+ to a versatile tetracarboxylate binding site3 modeled on and isosteric with the well known chelator EGTA. The most commonly used pH indicators are fluorescein dyes (such as BCECF) modified to adjust their pKa's and improve their retention inside cells. Na+ indicators are crown ethers with cavity sizes chosen to select Na+ over K+: Mg2+ indicators use tricarboxylate binding sites truncated from those of the Ca2+ chelators, resulting in a more compact arrangement of carboxylates to suit the smaller ion.

Various technic for the measurement of step thickness on crystal surfaces

1978 ◽  
Vol 36 (1) ◽  
pp. 438-439
Author(s):  
C. Boulesteix ◽  
C. Colliex ◽  
C. Mory ◽  
B. Pardo ◽  
D. Renard
Keyword(s):  
Critical Thickness ◽  
Symmetric Case ◽  
Transmitted Intensity ◽  
Crystal Surfaces ◽  
Bright Field ◽  
Excited Wave ◽  
Highly Sensitive ◽  
Contrast Mechanisms ◽  
Step Thickness ◽  
Thickness Variations

Contrast mechanisms, which are responsible of the various types of image formation, are generally thickness dependant. In the following, two imaging modes in the 100 kV CTEM are described : they are highly sensitive to thickness variations and can be used for quantitative estimations of step heights.Detailed calculations (1) of the bright-field intensity have been carried out in the 3 (or 2N+l)-beam symmetric case. They show that in given conditions, the two important symmetric Bloch waves interfere most strongly at a critical thickness for which they have equal emergent amplitudes (the more excited wave at the entrance surface is also the more absorbed). The transmitted intensity I for a Nd2O3 specimen has been calculated as a function of thickness t. The capacity of the method to detect a step and measure its height can be more clearly deduced from a plot of dl/Idt as shown in fig. 1.

Estimation of the noise in TEM image recorded on “imaging plate”

1987 ◽  
Vol 45 ◽  
pp. 748-749
Author(s):  
T. Oikawa ◽  
N. Mori ◽  
T. Katoh ◽  
Y. Harada ◽  
J. Miyahara ◽  
...  
Keyword(s):  
Low Dose ◽  
Quantum Noise ◽  
Laser Light ◽  
Imaging Plate ◽  
Total System ◽  
Electron Dose ◽  
X Ray ◽  
Image Recording ◽  
Recording Material ◽  
Highly Sensitive

The “Imaging Plate”(IP) is a highly sensitive image recording plate for X-ray radiography. It has been ascertained that the IP has superior properties and high practicability as an image recording material in a TEM. The sensitivity, one of the properties, is about 3 orders higher than that of conventional photo film. The IP is expected to be applied to low dose techniques. In this paper, an estimation of the quantum noise on the TEM image which appears in case of low electron dose on the IP is reported.In this experiment, the JEM-2000FX TEM and an IP having the same size as photo film were used.Figure 1 shows the schematic diagram of the total system including the TEM used in this experiment. In the reader, He-Ne laser light is scanned across the IP, then blue light is emitted from the IP.

High-sensitivity detection of gold labels by high-angle dark-field STEM imaging

1990 ◽  
Vol 48 (3) ◽  
pp. 892-893 ◽  
Author(s):  
Max T. Otten
Keyword(s):  
High Sensitivity ◽  
Dark Field ◽  
Bright Field ◽  
Backscattered Electron Imaging ◽  
Backscattered Electrons ◽  
Average Atomic Number ◽  
Highly Sensitive ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
High Sensitivity Detection

Labelling of antibodies with small gold probes is a highly sensitive technique for detecting specific molecules in biological tissue. Larger gold probes are usually well visible in TEM or STEM Bright-Field images of unstained specimens. In stained specimens, however, the contrast of the stain is frequently the same as that of the gold labels, making it virtually impossible to identify the labels, especially when smaller gold labels are used to increase the sensitivity of the immunolabelling technique. TEM or STEM Dark-Field images fare no better (Figs. 1a and 2a), again because of the absence of a clear contrast difference between gold labels and stain.Potentially much more useful is backscattered-electron imaging, since this will show differences in average atomic number which are sufficiently large between the metallic gold and the stains normally used. However, for the thin specimens and at high accelerating voltages of the STEM, the yield of backscattered electrons is very small, resulting in a very weak signal. Consequently, the backscattered-electron signal is often too noisy for detecting small labels, even for large spot sizes.

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