Search results for "Pentane"
showing 10 items of 174 documents
Strukturuntersuchungen von polyamiden aus cyclischen dicarbonsäuren und piperazin durch direkten abbau im massenspektrometer
1977
Polyamide aus 1,2-Cyclobutan-, 1,2-Cyclopentan- und 1,2-Cyclohexandicarbonsaure und Piperazin wurden direkt in der Ionenquelle eines Massenspektrometers pyrolysiert. Die hohe Empfindlichkeit der massenspektrometrischen Methode erlaubt, bei Abbauraten von ca. 1%/min zu pyrolysieren und dadurch selektive thermische Abbaumechanismen neben den Fragmentierungsreaktionen nachzuweisen. Durch thermischen Abbau werden dabei Oligomere mit Piperazinendgruppen sowie gesattigte und ungesattigte Cyclobutan-, -pentan- und -hexanendgruppen gebildet. Polyamides of 1,2-cyclobutane-, 1,2-cyclopentane- and 1,2-cyclohexane-dicarboxylic acid and piperazine were pyrolyzed directly in the ion source of a mass spec…
Cinema audiences reproducibly vary the chemical composition of air during films, by broadcasting scene specific emissions on breath
2016
AbstractHuman beings continuously emit chemicals into the air by breath and through the skin. In order to determine whether these emissions vary predictably in response to audiovisual stimuli, we have continuously monitored carbon dioxide and over one hundred volatile organic compounds in a cinema. It was found that many airborne chemicals in cinema air varied distinctively and reproducibly with time for a particular film, even in different screenings to different audiences. Application of scene labels and advanced data mining methods revealed that specific film events, namely “suspense” or “comedy” caused audiences to change their emission of specific chemicals. These event-type synchronou…
Coarse-graining dipolar interactions in simple fluids and polymer solutions: Monte Carlo studies of the phase behavior
2009
In this paper we investigate the phase diagram of pure dipolar substances and their mixtures with short alkanes, using grand canonical Monte Carlo simulations of simplified coarse-grained models. Recently, an efficient coarse-grained model for simple quadrupolar molecules, based on a Lennard-Jones (LJ) interaction plus a spherically averaged quadrupolar potential, has been shown to be successful in predicting single-component and mixture phase diagrams. Motivated by these results, we investigate the phase diagrams of simple dipolar molecules (and their mixtures with alkanes) using a spherically averaged potential. First, we test the model on pure components. A generalized (state-dependent) …
Antihyperalgesic and analgesic properties of the N-methyl-d-aspartate (NMDA) receptor antagonist neramexane in a human surrogate model of neurogenic …
2006
Abstract NMDA-receptors are a major target in the prevention and treatment of hyperalgesic pain states in neuropathic pain. However, previous studies revealed equivocal results depending on study design and efficacy parameters. We tested the analgesic (generalized reduction of generation and processing of nociceptive signalling) and anti-hyperalgesic (prevention of central sensitization) properties of the NMDA-receptor antagonist neramexane and the potassium channel opener flupirtine in the intradermal capsaicin injection model. Furthermore, we tested the effect on pain summation (wind up). Eighteen healthy subjects received either a single dose of neramexane (40 mg p.o.), flupirtine (100 m…
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…
Priming for JA-dependent defenses using hexanoic acid is an effective mechanism to protect Arabidopsis against B. cinerea
2011
Abstract Soil drench treatments with hexanoic acid can effectively protect Arabidopsis plants against Botrytis cinerea through a mechanism based on a stronger and faster accumulation of JA-dependent defenses. Plants impaired in ethylene, salicylic acid, abscisic acid or glutathion pathways showed intact protection by hexanoic acid upon B. cinerea infection. Accordingly, no significant changes in the SA marker gene PR-1 in either the SA or ABA hormone balance were observed in the infected and treated plants. In contrast, the JA signaling pathway showed dramatic changes after hexanoic acid treatment, mainly when the pathogen was present. The impaired JA mutants, jin1-2 and jar1 , were unable …
Combining Spontaneous Polymerization and Click Reactions for the Synthesis of Polymer Brushes: A "Grafting Onto" Approach
2013
Two novel benzofulvene monomers bearing propargyl or allyl groups have been synthesized by means of readily accessible reactions, and were found to polymerize spontaneously by solvent removal, in the apparent absence of catalysts or initiators, to give the corresponding polybenzofulvene derivatives bearing clickable propargyl or allyl moieties. The clickable propargyl and allyl groups were exploited in appropriate click reactions to develop a powerful and versatile "grafting onto" synthetic methodology for obtaining tailored polymer brushes.
Phospholipid breakdown and choline release under hypoxic conditions: inhibition by bilobalide, a constituent of Ginkgo biloba
1997
A marked increase of choline release from rat hippocampal slices was observed when the slices were superfused with oxygen-free buffer, indicating hypoxia-induced hydrolysis of choline-containing phospholipids. This increase of choline release was suppressed by bilobalide, an ingredient of Ginkgo biloba, but not by a mixture of ginkgolides. The EC50 value for bilobalide was 0.38 microM. In ex vivo experiments, bilobalide also inhibited hypoxia-induced choline release when given p.o. in doses of 2-20 mg/kg 1 h prior to slice preparation. The half-maximum effect was observed with 6 mg/kg bilobalide. A similar effect was noted after p.o. administration of 200 mg/kg EGb 761, a ginkgo extract con…
Contact Allergens Modulate the Expression of MHC Class II Molecules on Murine Epidermal Langerhans Cells by Endocytotic Mechanisms
1992
MHC class II molecules play an important role during the sensitization phase of allergic contact dermatitis. To study the influence of contact allergens on the expression of these molecules by murine epidermal Langerhans cells (LC), we performed a flow-cytofluorometric analysis of the Ia-antigen expression after in vivo application of contact allergens. A distinct decrease in the Ia-antigen expression of the entire LC population was noticed 3 h after in vivo application of the contact allergen 2,4-dinitrofluorobenzene (DNFB). This decrease was transient and balanced 24 h after in vivo application of DNFB. A downregulation was also detectable after in vivo application of the contact allergen…
Quantitative evaluation of ethane and n-pentane as indicators of lipid peroxidation in vivo.
1983
The use of exhalation of ethane and n-pentane in experimental animals as parameters of lipid peroxidation led to an examination of pharmacokinetics of both compounds in rats. When rats were exposed, in a closed desiccator jar chamber, to a wide range of ethane concentrations, linear elimination pharmacokinetics were observed. n-Pentane, when concentrations higher than 100 ppm were applied, displayed saturation kinetics. These were formally explained by action of two competing metabolizing pathways or enzymes. Application of preexisting models could describe exhalation of both ethane and n-pentane by untreated control rats. Stimulation of lipid peroxidation by ferrous ions or by carbon tetra…