Search results for "Methylamine"
showing 10 items of 97 documents
Description and commissioning of NEXT-MM prototype: first results from operation in a Xenon-Trimethylamine gas mixture
2014
[EN] A technical description of NEXT-MM and its commissioning and first performance is reported. Having an active volume of ∼35 cm drift × 28 cm diameter, it constitutes the largest Micromegas-read TPC operated in Xenon ever constructed, made by a sectorial arrangement of the 4 largest single wafers manufactured with the Microbulk technique to date. It is equipped with a suitably pixelized readout and with a sufficiently large sensitive volume (∼23 l) so as to contain long (∼20 cm) electron tracks. First results obtained at 1 bar for Xenon and Trymethylamine (Xe-(2%)TMA) mixture are presented. The TPC can accurately reconstruct extended background tracks. An encouraging fu…
The molecular basis of the low hemolytic activity of C4 molecules from low-C4 mice with IgM-coated erythrocytes.
1989
This study investigated the origin of the different hemolytic activity of two allotypes of murine C4, C4H (C4-high) and C4L (C4-low) in the presence of IgM-coated erythrocytes. C4H displayed a threefold higher hemolytic titer (expressed in hemolytic units/microgram protein) than C4L. No difference was found between c4H and C4L either in stability at 37 degrees C at different pH values and in the rate of C4H and C4L hydrolysis by activated Cl. The major functional difference was found in the covalent binding capacity to IgM-coated erythrocytes, with the amount of C4H bound being about threefold higher than that of C4L. A marked difference in the reactivity of the C4b fragment of C4H and C4L …
An evaluation of solid phase microextraction for aliphatic amines using derivatization with 9-fluorenylmethyl chloroformate and liquid chromatography
2005
The reliability of SPME combined with a chemical reaction for the analysis of short-chain aliphatic amines by liquid chromatography has been investigated. Different options to couple SPME and derivatization have been tested and compared: (i) derivatization of the analytes in solution followed by the extraction of the derivatives, (ii) extraction of the analytes and subsequent derivatization by immersing the SPME fibre onto a solution of the reagent, and (iii) extraction/derivatization of the analytes using fibres previously coated with the reagent. Methylamine (MA), dimethylamine (DMA) and trimethylamine (TMA) have been selected as a model of primary, secondary and tertiary amines, respecti…
Optical sensing responses of CrIIICl(TPP)(H2O)-based coatings obtained by an atmospheric pressure plasma method – Application to the detection of vol…
2014
Food spoilage processes are a considerable concern for both the food industry and the consumer, due to financial, food quality and food safety aspects. A primary issue is the prevention/monitoring of the formation of biogenic and volatile amines, such as occurring in fish and in other microbiologically unstable food items rich in proteins, produced by e.g. oxidative decarboxylation of amino acids. One strategy for their monitoring is the development of films with colorimetric sensing properties that are able to indicate food spoilage. The aim of this investigation was the development of a novel metalloporphyrin-based coating allowing the sensitive detection of typical volatile amines, such …
Designing solid optical sensors for in situ passive discrimination of volatile amines based on a new one-step hydrophilic PDMS preparation
2016
Abstract We reported an optimal material for embedding chemoresponsive dyes based on modified commercial PDMS. A new approach to impart hydrophilicity to H-PDMS in an unique step was developed by addition of tetraethyl orthosilicate (TEOS) and in absence of basic or acid aqueous mixtures or hydroxyl-compounds during the PDMS coating process. This incorporation significantly enhances the performance of PDMS-based devices for sensing applications. New colorimetric sensors for passive detection and in situ discrimination of volatile amines have been obtained. The limit of detection achieved was 1.5 mg m −3 for both, dimethylamine and methylamine, suitable to control real working atmospheres. T…
Synthesis and antiproliferative activity of triazenoindazoles and triazenopyrazoles: a comparative study.
2003
Several triazenoindazoles and triazenopyrazoles were prepared transforming the appropriate aminoindazoles and aminopyrazoles in the corresponding diazonium salts which were reacted with dimethylamine, diethylamine and pyrrolidine. All the triazenes were tested for their antiproliferative activity against K562, HL60, L1210 and MCF7 cell lines. The biological data showed that the benzocondensation plays a positive role on the antiproliferative activity. The (1)H-NMR spectra showed that the rotational barrier around the N(2)-N(3) bond in the triazene group can be influenced both by the position of this group in the indazole nucleus and by the substitution pattern in the benzene moiety.
Bis(dichlorosilyl)methylamine - Synthesis, Crystal Structure, and Conformational Analysis in the Gas Phase
1999
A straightforward preparation has been found for bis(dichlorosilyl)methylamine, (SiHCl2)2NMe (1), involving reaction between H2NMe and an excess of SiHCl3, dissolved either in pentane or THF at 253 K. 1 and a side-product, 1,3,5-trichloro-2,4,6-trimethylcyclotrisilazane, (–SiHCl–NMe–)3 (2), were identified by elemental analysis, mass spectrometry and 1H-NMR-spectroscopy. Some physical, NMR- and IR spectroscopical properties of 1 were determined. The molecular and crystal structure of 1 was investigated by single crystal X-ray diffraction. Selected structural parameters: r(Si–N) 169.7(5), r(Si–Cl) 203.1(2)–204.4(2), r(C–N) 150.0(8) pm; a(SiNSi) 123.6(3), a(SiNC) 118.3(4)/118.0(4)°. Ab initio…
Nonheme Fe(IV) Oxo Complexes of Two New Pentadentate Ligands and Their Hydrogen-Atom and Oxygen-Atom Transfer Reactions.
2015
Two new pentadentate {N5} donor ligands based on the N4Py (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) framework have been synthesized, viz. [N-(1-methyl-2-benzimidazolyl)methyl-N-(2-pyridyl)methyl-N-(bis-2-pyridyl methyl)amine] (L1) and [N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L2), where one or two pyridyl arms of N4Py have been replaced by corresponding (N-methyl)benzimidazolyl-containing arms. The complexes [FeII(CH3CN)(L)]2+ (L = L1 (1); L2 (2)) were synthesized, and reaction of these ferrous complexes with iodosylbenzene led to the formation of the ferryl complexes [FeIV(O)(L)]2+ (L = L1 (3); L2 (4)), which were characterized by UV–vis spe…
Aminoallenylidene complexes of ruthenium(II) from the regioselective addition of secondary amines to butatrienylidene intermediates: a combined exper…
2003
Aminoallenylidene complexes trans-[Cl(dppm)2RuC3(NRR )(CH3)] are obtained from the regioselective addition of secondary amines to trans-[Cl(dppm)2Ru C C C CH2] . Unsymmetrically substituted amines give rise to Z/E isomeric mixtures. Dynamic 31P NMR spectroscopy gave an energy barrier of about 85 kJ mol 1 for rotation around the CN-bond pointing to a large contribution of the iminium alkynyl resonance form trans-[Cl(dppm)2Ru–C C– C( NRR )(CH3)] . This is also indicated by the pronounced bond length alternation within the RuC3N-chain as is revealed by X-ray structure analysis of the Z isomer of the (benzylmethyl)methylamine derivative 2d. The issue of NR2 rotation was also addressed by DFT ca…
Characterization of a medium size Xe/TMA TPC instrumented with microbulk Micromegas, using low-energy gamma-rays
2014
NEXT-MM is a general-purpose high pressure (10 bar, $\sim25$ l active volume) Xenon-based TPC, read out in charge mode with an 8 cm $\times$8 cm-segmented 700 cm$^2$ plane (1152 ch) of the latest microbulk-Micromegas technology. It has been recently commissioned at University of Zaragoza as part of the R&D of the NEXT $0\nu\beta\beta$ experiment, although the experiment's first stage is currently being built based on a SiPM/PMT-readout concept relying on electroluminescence. Around 2 million events were collected during the last months, stemming from the low energy $\gamma$-rays emitted by a $^{241}$Am source when interacting with the Xenon gas ($\epsilon$ = 26, 30, 59.5 keV). The localized…