Search results for "PIP"
showing 10 items of 1156 documents
Chances in the Brain Cells, From Epigenetic To the Future
2014
Copyright: © 2014 Valles SL. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Both oxidative damage and inflammation are elevated in brain from neurodegenerative patients [1], but their pathogenic significance remains unclear. Central nervous system has its own resident immune system, in which glial cells not only serve such as supportive and nutritive roles for neuron cells, also engage in several inflammatory processes that defend the central nervous system from pathogens and help it to recover from stres…
1,3-Dipolar cycloaddition of diaryldiazomethanes across N-ethoxy-carbonyl-N-(2,2,2-trichloroethylidene)amine and reactivity of the resulting 2-azabut…
2016
Abstract 1,3-dipolar cycloaddition of diaryldiazomethanes Ar2C N2 across Cl3C–CH N–CO2Et 1 yields Δ3-1,2,4-triazolines 2. Thermolysis of 2 leads, via transient azomethine ylides 3, to diaryldichloroazabutadienes [Ar(Ar')C N–CH CCl2] 4. Treatment of 4a (Ar = Ar' = C6H5) and 4c (Ar = Ar' = p-ClC6H4) with NaSR in DMF yields 2-azabutadienes [Ar2C N–C(H) C(SR)2] 5. In contrast, nucleophilic attack of NaStBu on 4 affords azadienic dithioethers [Ar2C N–C(StBu) C(H)(StBu)] (7a Ar = C6H5; 7b Ar' = p-ClC6H4). The reaction of 4a with NaSEt conducted in neat EtSH produces [Ph2C N–C(H)(SEt)–CCl2H] 8, which after dehydrochloration by NaOMe and subsequent addition of NaSEt is converted to [Ph2C N–C(SEt) C…
Stereoselective syntheses of piperidinones and their modification by organometallic coupling reactions
2007
Dehydropiperidinones stereoselectively obtained from N-arabinosyl imines were iodinated at the enaminone structure. Knochel iodine-magnesium exchange afforded Grignard compounds of these piperidinone derivatives which reacted, either directly or after transmetalation to zinc or copper intermediates, with alkyl-, aryl- or acylhalides to give correspondingly substituted piperidinones. Stereoselective conjugate allyl cuprate addition to a thus obtained 5-allyl dehydropiperidinone and ring-closing metathesis of the product gave a hydroquinolinone containing three stereogenic centers.
Electrodeposition methods in superheavy element chemistry
2008
To prepare electrodeposition experiments with superheavy elements (SHE), their homologs were investigated. In the experiments, various electrode materials and electrolytes were used. Critical potentials (E crit ) where the electrodeposition starts and potentials for the deposition of 50% of the atoms in solution (E 50% ) were determined. Underpotential deposition was observed in most cases. An electrolytic cell for a fast electrochemical deposition was developed and the time for the deposition of 50% of the atoms in solution (t 50% ) was determined. Short lived α-emitting isotopes were produced at Gesellschaft fur Schwerionenforschung (GSI), Darmstadt, transferred to the aqueous phase with …
Recyclable Catalyst Reservoir: Oxidation of Alcohols Mediated by Noncovalently Supported Bis(imidazolium)-Tagged 2,2,6,6-Tetramethylpiperidine 1-Oxyl
2013
Bis(imidazolium)-tagged 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) catalysts were adsorbed on different supports such as silica gel, silica gel modified with highly cross-linked polymeric imidazolium networks, and highly cross-linked polymeric imidazolium networks entrapping magnetic particles. These systems provided a convenient tool for the oxidation of both primary and secondary alcohols working as recyclable reservoirs for the bis(imidazolium)-tagged TEMPO catalysts. By using EPR spectroscopy it was demonstrated that the catalyst was released as the corresponding oxoammonium salt in the solution during the recycling step, thus promoting the oxidative process in a homogeneous fashion. …
How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?
2015
This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1). For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace chang…
Separation and identification of piperine and chavicine in black pepper by TLC and GC-MS
2006
Conventional extraction of piperine and its derivatives by stirring the black pepper powder with solvents (ethyl alcohol, chloroform, petroleum ether, diethyl ether, etc.) for 16 to 24 h, or in a Soxhlet device for 16 h, can be replaced by extraction with supercritical fluids (CO 2 , CO + ethanol mixtures) [5, 6], or can be aided by use of microwave irradiation [7]. Separation and identification of the compounds present in pepper (essential oils, alkaloids, etc.) has been achieved by gas chromatography combined with mass spectrometry [8] and by thin-layer chromatography [9, 10]. C. Marutoiu, M.I. Moise, Lucian Blaga University of Sibiu, Faculty of Agricultural Sciences, Food Industry, and E…
Determination of quinolone residues in chicken and fish by capillary electrophoresis-mass spectrometry
2006
A specific pressure-assisted CE-MS method is described for the analysis of five quinolone residues. MS using a single quadrupole is compared with multiple-stage MS using a quadrupole IT (QIT-MS(n)). The procedure involves a common sample preparation by SPE on disposable cartridges. The most suitable electrolyte is 60 mM (NH(4))(2)CO(3) at pH 9.2. Single quadrupole does not provide enough fragmentation to confirm identities according to the current legislation. However, QIT-MS(n) achieves selective fragmentation. Using this method, danofloxacin, enrofloxacin, flumequine, ofloxacin, and pipemidic acid are analyzed in fortified samples of chicken and fish. Recoveries at levels of 50 ng/g were …
Study on the efficiency of assembled packed microbore columns in HPLC
1984
Stainless steel columns (internally mirror-finished, 125 or 250nm in length, of bore 1.0 or 1.6mm) were slurry-packed with 5µm and 4µm reversed phase silicas (Hypersil ODS, LiChrosorb RP-8 and RP-18 and Superspher RP-8. The HPLC equipment consisted of a pump LC5A (Shimadzu) or a pump 2150 (LKB Instruments), a rheodyne valve 7413 with loops of 0.5, 1.0 and 5.0mm3 and a Jasco-Uvidec 100-II UV detector, variously with one of three specially constructed cells of 0.2, 0.4 and 1.3mm3 volume. Columns were assembled using two types of coupling device employing a stainless steel capillary of 0.12mm bore. The effect of sample volume, design of coupling device in assembled column, detector cell volume…
Spectrophotometric determination of nalidixic and pipemidic acids in a flow injection assembly with a solid-phase reactor as a highly stable reagent …
2001
Abstract The flow-injection spectrophotometric determination of nalidixic (I) and pipemidic (II) acids were carried out by reaction with Fe(III) ions entrapped in a polymeric material and filling a packed-bed reactor; the released Fe(III) complexed with the quinolone is monitored at 426 nm. The method worked with a high reproducibility, even when using different reactors, days and solutions. Selectivity of the procedure was tested with different foreign compounds found in human urine as well as in pharmaceutical formulations containing both quinolones; no relevant interferences were observed. The calibration graph for (I) was linear over the range 1–250 μg ml −1 with a relative standard dev…