scholarly journals New Developments in Scanning Microelectrochemical Techniques: A Highly Sensitive Route to Evaluate Degradation Reactions and Protection Methods with Chemical Selectivity

2018 ◽  
Vol 875 ◽  
pp. 19-23
Author(s):  
Ricardo M. Souto ◽  
Dániel Filotás ◽  
Bibiana M. Fernández-Pérez ◽  
Lívia Nagy ◽  
Géza Nagy
Keyword(s):  
Galvanized Steel ◽  
New Developments ◽  
Saline Environment ◽  
Spatially Resolved ◽  
Degradation Reactions ◽  
Ion Distributions ◽  
Scanning Electrochemical Microscope ◽  
Highly Sensitive ◽  
Chemical Selectivity

The scanning electrochemical microscope (SECM) offers a highly sensitive route to evaluate degradation reactions and protection methods with chemical selectivity by using ion-selective microelectrodes as tips, thus operating SECM potentiometrically. Spatially resolved imaging of electrochemical reactivity related to each component of the investigated material can thus be effectively monitored selectively both in situ and in real time. The applicability of this method has been illustrated using a practical example of a metal-coating system, consisting in the exposure of cut edges of coil-coated galvanized steel to aqueous saline environment. In this contribution, localized pH and zinc(II) ion distributions originated around cut edges of coil coated steel immersed in 1 mM NaCl solution are shown.

FT-IR microspectroscopic analysis of diseased white matter brain tissues

1995 ◽  
Vol 53 ◽  
pp. 968-969
Author(s):  
Steven M. Le Vine ◽  
David L. Wetzel
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Twitcher Mouse ◽  
Grid Pattern ◽  
Marked Contrast ◽  
Spatially Resolved ◽  
Ft Ir ◽  
Ir Microspectroscopy ◽  
Chemical Evidence

In situ FT-IR microspectroscopy has allowed spatially resolved interrogation of different parts of brain tissue. In previous work the spectrrscopic features of normal barin tissue were characterized. The white matter, gray matter and basal ganglia were mapped from appropriate peak area measurements from spectra obtained in a grid pattern. Bands prevalent in white matter were mostly associated with the lipid. These included 2927 and 1469 cm-1 due to CH2 as well as carbonyl at 1740 cm-1. Also 1235 and 1085 cm-1 due to phospholipid and galactocerebroside, respectively (Figs 1and2). Localized chemical changes in the white matter as a result of white matter diseases have been studied. This involved the documentation of localized chemical evidence of demyelination in shiverer mice in which the spectra of white matter lacked the marked contrast between it and gray matter exhibited in the white matter of normal mice (Fig. 3).The twitcher mouse, a model of Krabbe’s desease, was also studied. The purpose in this case was to look for a localized build-up of psychosine in the white matter caused by deficiencies in the enzyme responsible for its breakdown under normal conditions.

scholarly journals Spatially Resolved Experimental Modal Analysis on High-Speed Composite Rotors Using a Non-Contact, Non-Rotating Sensor

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4705
Author(s):  
Julian Lich ◽  
Tino Wollmann ◽  
Angelos Filippatos ◽  
Maik Gude ◽  
Juergen Czarske ◽  
...  
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Fiber Reinforced ◽  
Structural Dynamic ◽  
Spatially Resolved ◽  
Glass Fiber Reinforced ◽  
Vibration Responses ◽  
And Performance

Due to their lightweight properties, fiber-reinforced composites are well suited for large and fast rotating structures, such as fan blades in turbomachines. To investigate rotor safety and performance, in situ measurements of the structural dynamic behaviour must be performed during rotating conditions. An approach to measuring spatially resolved vibration responses of a rotating structure with a non-contact, non-rotating sensor is investigated here. The resulting spectra can be assigned to specific locations on the structure and have similar properties to the spectra measured with co-rotating sensors, such as strain gauges. The sampling frequency is increased by performing consecutive measurements with a constant excitation function and varying time delays. The method allows for a paradigm shift to unambiguous identification of natural frequencies and mode shapes with arbitrary rotor shapes and excitation functions without the need for co-rotating sensors. Deflection measurements on a glass fiber-reinforced polymer disk were performed with a diffraction grating-based sensor system at 40 measurement points with an uncertainty below 15 μrad and a commercial triangulation sensor at 200 measurement points at surface speeds up to 300 m/s. A rotation-induced increase of two natural frequencies was measured, and their mode shapes were derived at the corresponding rotational speeds. A strain gauge was used for validation.

scholarly journals Spatial expression pattern of serine proteases in the blood fluke Schistosoma mansoni determined by fluorescence RNA in situ hybridization

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lenka Ulrychová ◽  
Pavel Ostašov ◽  
Marta Chanová ◽  
Michael Mareš ◽  
Martin Horn ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Schistosoma Mansoni ◽  
Rna Sequencing ◽  
Serine Proteases ◽  
Expression Patterns ◽  
High Sensitivity ◽  
Host Parasite Interactions ◽  
Highly Sensitive ◽  
Host Parasite

Abstract Background The blood flukes of genus Schistosoma are the causative agent of schistosomiasis, a parasitic disease that infects more than 200 million people worldwide. Proteases of schistosomes are involved in critical steps of host–parasite interactions and are promising therapeutic targets. We recently identified and characterized a group of S1 family Schistosoma mansoni serine proteases, including SmSP1 to SmSP5. Expression levels of some SmSPs in S. mansoni are low, and by standard genome sequencing technologies they are marginally detectable at the method threshold levels. Here, we report their spatial gene expression patterns in adult S. mansoni by the high-sensitivity localization assay. Methodology Highly sensitive fluorescence in situ RNA hybridization (FISH) was modified and used for the localization of mRNAs encoding individual SmSP proteases (including low-expressed SmSPs) in tissues of adult worms. High sensitivity was obtained due to specifically prepared tissue and probes in combination with the employment of a signal amplification approach. The assay method was validated by detecting the expression patterns of a set of relevant reference genes including SmCB1, SmPOP, SmTSP-2, and Sm29 with localization formerly determined by other techniques. Results FISH analysis revealed interesting expression patterns of SmSPs distributed in multiple tissues of S. mansoni adults. The expression patterns of individual SmSPs were distinct but in part overlapping and were consistent with existing transcriptome sequencing data. The exception were genes with significantly low expression, which were also localized in tissues where they had not previously been detected by RNA sequencing methods. In general, SmSPs were found in various tissues including reproductive organs, parenchymal cells, esophagus, and the tegumental surface. Conclusions The FISH-based assay provided spatial information about the expression of five SmSPs in adult S. mansoni females and males. This highly sensitive method allowed visualization of low-abundantly expressed genes that are below the detection limits of standard in situ hybridization or by RNA sequencing. Thus, this technical approach turned out to be suitable for sensitive localization studies and may also be applicable for other trematodes. The results suggest that SmSPs may play roles in diverse processes of the parasite. Certain SmSPs expressed at the surface may be involved in host–parasite interactions. Graphic abstract

scholarly journals Airborne determination of the temporo-spatial distribution of benzene, toluene, nitrogen oxides and ozone in the boundary layer across Greater London, UK

2015 ◽  
Vol 15 (9) ◽  
pp. 5083-5097 ◽  
Author(s):  
M. D. Shaw ◽  
J. D. Lee ◽  
B. Davison ◽  
A. Vaughan ◽  
R. M. Purvis ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Nitrogen Oxides ◽  
Linear Regression Analysis ◽  
Proton Transfer Reaction ◽  
Mixing Ratios ◽  
Spatially Resolved ◽  
Dual Channel ◽  
Benzene Toluene

Abstract. Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NOx) and ozone (O3) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in situ using a proton transfer reaction mass spectrometer (PTR-MS), NOx by dual-channel NOx chemiluminescence and O3 mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO2 and NOx respectively. Linear regression analysis between NO2, benzene and toluene mixing ratios yields a strong covariance, indicating that these compounds predominantly share the same or co-located sources within the city. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.5 ppbv ppbv-1), indicative of strong local sources. Daytime maxima in NOx, benzene and toluene mixing ratios were observed in the morning (~ 40 ppbv NOx, ~ 350 pptv toluene and ~ 200 pptv benzene) and in the mid-afternoon for ozone (~ 40 ppbv O3), all at 360 ± 10 m a.g.l.

In Situ Biaxial Mechanical Testing at the Neutron Time-of-Flight Diffractometer POLDI

2013 ◽  
Vol 768-769 ◽  
pp. 60-65 ◽  
Author(s):  
Julia Repper ◽  
Markus Niffenegger ◽  
Steven van Petegem ◽  
Werner Wagner ◽  
Helena van Swygenhoven
Keyword(s):  
Steel Sample ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Uniaxial Deformation ◽  
Spatially Resolved ◽  
Neutron Diffractometer ◽  
Neutron Time ◽  
Strain Paths ◽  
Biaxial Mechanical Testing

Complex strain paths are often applied to materials during production processes. This paper shows the first successful in-situ biaxial mechanical tests during neutron diffraction performed on a cruciform steel sample and reports on the differences compared to uniaxial deformation. Digital image correlation is demonstrated to be an appropriate tool to monitor spatially resolved the macroscopic straining. The new, modular biaxial machine that will be installed at the neutron diffractometer POLDI is presented.

A highly sensitive chlorine gas sensor and enhanced thermal DC electrical conductivity from polypyrrole/silicon carbide nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 84200-84208 ◽  
Author(s):  
Adil Sultan ◽  
Sharique Ahmad ◽  
Faiz Mohammad
Keyword(s):  
Electrical Conductivity ◽  
Silicon Carbide ◽  
Gas Sensor ◽  
Dodecylbenzenesulfonic Acid ◽  
Chemical Polymerization ◽  
Dc Electrical Conductivity ◽  
Highly Sensitive ◽  
Chlorine Gas

We report the synthesis of polypyrrole (PPy) and polypyrrole/silicon carbide nanocomposites (PPy/SiC) and PPy/SiC/dodecylbenzenesulfonic acid (DBSA) by in situ chemical polymerization and their application as sensors for the detection of highly toxic chlorine gas.

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