Detection of Nitro-aromatic Compound in Soil and Sand using Time Gated Raman Spectroscopy

2017 ◽  
Vol 67 (5) ◽  
pp. 588 ◽  
Author(s):  
Kamal Kumar Gulati ◽  
Vijayeta Gambhir ◽  
M. N. Reddy
Keyword(s):  
Raman Spectroscopy ◽  
Benzoic Acid ◽  
Signal To Noise Ratio ◽  
Terrorist Attack ◽  
Laser Pulses ◽  
High Background ◽  
Detection And Identification ◽  
Set Up ◽  
Detection Of Explosives ◽  
Nitro Aromatic

<p>Laser based time-gated Raman Spectroscopy experiments for detection and identification of nitro-aromatic sample which premixed with soil and sand in different concentrations are conducted. A back-scattered stand-off Raman spectroscopy set-up using a frequency double Nd:YAG pulsed laser (532 nm, 8 ns, 10 Hz) was employed to evaluate samples made up of standard nitro- aromatic compounds, p-nitro Benzoic acid (PNBA) premixed with soil and sand at different concentrations. A sensitive ICCD detector was used to capture the weak Raman signals buried in high background noise at optimised experiments parameters like laser pulse energy, ICCD gate width, background subtraction, number of laser pulses averaging etc. p- nitro benzoic acid up to 5 per cent (v/v) concentration in sand with appreciable signal to noise ratio has been detected. This feasibility study also becomes relevant to evaluate the remnants for post-blast detection of explosives in terrorist attack as most of the explosives used in such attacks contain nitro-aromatic based high energetic explosives.</p>

scholarly journals Standoff Detection and Identification of Explosives and Hazardous Chemicals in Simulated Real Field Scenario using Time Gated Raman Spectroscopy

2019 ◽  
Vol 69 (4) ◽  
pp. 342-347 ◽  
Author(s):  
Kamal Kumar Gulati ◽  
Sanjay Gulia ◽  
Tanvi Gambhir ◽  
Nitesh Kumar ◽  
Vijayeta Gambhir ◽  
...  
Keyword(s):  
Experimental Study ◽  
Raman Spectroscopy ◽  
Energetic Materials ◽  
Real Field ◽  
Hazardous Chemicals ◽  
Security Screening ◽  
Detection And Identification ◽  
And Performance ◽  
Improvised Explosive ◽  
Detection Of Explosives

The detection of hazardous chemicals, explosives, improvised explosive materials, energetic materials and their associated compounds for security screening, forensic applications and detection of unexploded ordnance is an active area of research. The results based on comprehensive experimental study and performance of time gated Raman spectroscopy (TGRS) for stand-off detection of explosives and hazardous chemicals under realistic scenario are presented. Representative results drawn from the experimental study for detection of explosives and hazardous chemicals in simulated real field scenario are given.

o-Alkylselenenylated Benzoic Acid Accesses Several Sites in Serum Albumin According to Fluorescence Studies, Raman Spectroscopy and Theoretical Simulations

2013 ◽  
Vol 20 (6) ◽  
pp. 705-714 ◽  
Author(s):  
Federico Martinez-Ramos ◽  
Yadira Fonseca-Sabater ◽  
Marvin A. Soriano-Ursua ◽  
Eduardo Torres ◽  
Martha C. Rosales-Hernandez ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Benzoic Acid ◽  
Serum Albumin ◽  
Fluorescence Studies ◽  
Theoretical Simulations

scholarly journals The Reporter System for GPCR Assay with the Fission YeastSchizosaccharomyces pombe

Scientifica ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Shintaro Sasuga ◽  
Toshiya Osada
Keyword(s):  
Fluorescent Protein ◽  
Signal To Noise Ratio ◽  
Biological Activities ◽  
Inducible Promoter ◽  
Upstream Region ◽  
Reporter Plasmid ◽  
Reporter System ◽  
High Background ◽  
Downstream Region ◽  
Green Fluorescent

G protein-coupled receptors (GPCRs) are associated with a great variety of biological activities. Yeasts are often utilized as a host for heterologous GPCR assay. We engineered the intense reporter plasmids for fission yeast to produce green fluorescent protein (GFP) through its endogenous GPCR pathway. As a control region of GFP expression on the reporter plasmid, we focused on seven endogenous genes specifically activated through the pathway. When upstream regions of these genes were used as an inducible promoter in combination with LPI terminator, themam2upstream region produced GFP most rapidly and intensely despite the high background. Subsequently, LPI terminator was replaced with the corresponding downstream regions. The SPBC4.01 downstream region enhanced the response with the low background. Furthermore, combining SPBC4.01 downstream region with the sxa2 upstream region, the signal to noise ratio was obviously better than those of other regions. We also evaluated the time- and dose-dependent GFP productions of the strains transformed with the reporter plasmids. Finally, we exhibited a model of simplified GPCR assay with the reporter plasmid by expressing endogenous GPCR under the control of the foreign promoter.

scholarly journals Investigation of Biotransformation Products of p-Methoxymethylamphetamine and Dihydromephedrone in Wastewater by High-Resolution Mass Spectrometry

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 66
Author(s):  
Juliet Kinyua ◽  
Aikaterini K. Psoma ◽  
Nikolaos I. Rousis ◽  
Maria-Christina Nika ◽  
Adrian Covaci ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Wastewater Treatment Plants ◽  
High Resolution Mass Spectrometry ◽  
Transformation Products ◽  
New Psychoactive Substances ◽  
Batch Reactors ◽  
Flight Mass Spectrometry ◽  
Detection And Identification ◽  
Wastewater Samples ◽  
Set Up

There is a paucity of information on biotransformation and stability of new psychoactive substances (NPS) in wastewater. Moreover, the fate of NPS and their transformation products (TPs) in wastewater treatment plants is not well understood. In this study, batch reactors seeded with activated sludge were set up to evaluate biotic, abiotic, and sorption losses of p-methoxymethylamphetamine (PMMA) and dihydromephedrone (DHM) and identify TPs formed during these processes. Detection and identification of all compounds was performed with target and suspect screening approaches using liquid chromatography quadrupole-time-of-flight mass spectrometry. Influent and effluent 24 h composite wastewater samples were collected from Athens from 2014 to 2020. High elimination rates were found for PMMA (80%) and DHM (97%) after a seven-day experiment and degradation appeared to be related to biological activity in the active bioreactor. Ten TPs were identified and the main reactions were O- and N-demethylation, oxidation, and hydroxylation. Some TPs were reported for the first time and some were confirmed by reference standards. Identification of some TPs was enhanced by the use of an in-house retention time prediction model. Mephedrone and some of its previously reported human metabolites were formed from DHM incubation. Retrospective analysis showed that PMMA was the most frequently detected compound.

scholarly journals A large area diamond-based beam tagging hodoscope for ion therapy monitoring

2018 ◽  
Vol 170 ◽  
pp. 09005 ◽  
Author(s):  
M.-L. Gallin-Martel ◽  
L. Abbassi ◽  
A. Bes ◽  
G. Bosson ◽  
J. Collot ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Signal To Noise Ratio ◽  
Therapy Monitoring ◽  
Chemical Vapor ◽  
X Rays ◽  
Reaction Products ◽  
Large Area ◽  
Position Measurement ◽  
Set Up ◽  
Good Signal

The MoniDiam project is part of the French national collaboration CLaRyS (Contrôle en Ligne de l’hAdronthérapie par RaYonnements Secondaires) for on-line monitoring of hadron therapy. It relies on the imaging of nuclear reaction products that is related to the ion range. The goal here is to provide large area beam detectors with a high detection efficiency for carbon or proton beams giving time and position measurement at 100 MHz count rates (beam tagging hodoscope). High radiation hardness and intrinsic electronic properties make diamonds reliable and very fast detectors with a good signal to noise ratio. Commercial Chemical Vapor Deposited (CVD) poly-crystalline, heteroepitaxial and monocrystalline diamonds were studied. Their applicability as a particle detector was investigated using α and β radioactive sources, 95 MeV/u carbon ion beams at GANIL and 8.5 keV X-ray photon bunches from ESRF. This facility offers the unique capability of providing a focused (~1 μm) beam in bunches of 100 ps duration, with an almost uniform energy deposition in the irradiated detector volume, therefore mimicking the interaction of single ions. A signal rise time resolution ranging from 20 to 90 ps rms and an energy resolution of 7 to 9% were measured using diamonds with aluminum disk shaped surface metallization. This enabled us to conclude that polycrystalline CVD diamond detectors are good candidates for our beam tagging hodoscope development. Recently, double-side stripped metallized diamonds were tested using the XBIC (X Rays Beam Induced Current) set-up of the ID21 beamline at ESRF which permits us to evaluate the capability of diamond to be used as position sensitive detector. The final detector will consist in a mosaic arrangement of double-side stripped diamond sensors read out by a dedicated fast-integrated electronics of several hundreds of channels.

scholarly journals Now you see it, now you don't: optimal parameters for interslice stimulation in concurrent TMS-fMRI

2021 ◽  
Author(s):  
Catriona L Scrivener ◽  
Jade B Jackson ◽  
Marta Morgado Correia ◽  
Marius Mada ◽  
Alexandra Woolgar
Keyword(s):  
Single Channel ◽  
Signal To Noise Ratio ◽  
Brain Activity ◽  
Surface Coil ◽  
Acquisition Time ◽  
Surface Coils ◽  
Human Participant ◽  
Set Up ◽  
Promising Avenue ◽  
Slice Acquisition

The powerful combination of transcranial magnetic stimulation (TMS) concurrent with functional magnetic resonance imaging (fMRI) provides rare insights into the causal relationships between brain activity and behaviour. Despite a recent resurgence in popularity, TMS-fMRI remains technically challenging. Here we examined the feasibility of applying TMS during short gaps between fMRI slices to avoid incurring artefacts in the fMRI data. We quantified signal dropout and changes in temporal signal-to-noise ratio (tSNR) for TMS pulses presented at timepoints from 100ms before to 100ms after slice onset. Up to 3 pulses were delivered per volume using MagVenture's MR-compatible TMS coil. We used a spherical phantom, two 7-channel TMS-dedicated surface coils, and a multiband (MB) sequence (factor=2) with interslice gaps of 100ms and 40ms, on a Siemens 3T Prisma-fit scanner. For comparison we repeated a subset of parameters with a more standard single-channel TxRx (birdcage) coil, and with a human participant and surface coil set up. We found that, even at 100% stimulator output, pulses applied at least -40ms/+50ms from the onset of slice readout avoid incurring artifacts. This was the case for all three setups. Thus, an interslice protocol can be achieved with a frequency of up to ~10 Hz, using a standard EPI sequence (slice acquisition time: 62.5ms, interslice gap: 40ms). Faster stimulation frequencies would require shorter slice acquisition times, for example using in-plane acceleration. Interslice TMS-fMRI protocols provide a promising avenue for retaining flexible timing of stimulus delivery without incurring TMS artifacts.

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