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11.
Development of a Simple and Fast Electrochemical Method for Screening and Stoichiometric Determination of Dimenhydrinate
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Jhonys Machado Freitas Thiago da Costa Oliveira Polyana Luiza Silva Denise Tofanello Gimenes Rodrigo Alejandro Abarza Munoz Eduardo Mathias Richter 《Electroanalysis》2014,26(9):1905-1911
Dimenhydrinate (DIM) is a salt composed by the combination of two active pharmaceutical ingredients: diphenhydramine (DIP) and 8‐chlorotheophylline (CTP). In this work, the use of batch injection analysis with multiple pulse amperometric detection (BIA‐MPA) was proposed for the first time for fast stoichiometric determination of DIM. DIP (cation) and CTP (anion) were determined simultaneously in pharmaceutical samples with a simple and fast injection procedure (70 injections h?1). Additional strategies were also proposed for rapid screening of samples containing the DIM salt. By a simple injection of a sample into the BIA system (without using of calibration curve), reliable information about stoichiometry of the DIM salt (1 : 1; DIP:CTP) and presence or absence of interfering species (electroactive) can be achieved. 相似文献
12.
The presentation of the quantum cohomology of the moduli spaceof stable vector bundles of rank two and odd degree with fixeddeterminant over a Riemann surface of genus g > 2 is obtained.The argument avoids the use of gauge theory, providing an alternativeproof to that given by the author in Duke Math. J. 98 (1999)525540. 2000 Mathematics Subject Classification 14N35(primary); 14H60, 53D45 (secondary). 相似文献
13.
Denise Tofanello Gimenes Wallans Torres Pio dos Santos Rodrigo Alejandro Abarza Munoz Eduardo Mathias Richter 《Electrochemistry communications》2010,12(2):216-218
In this work, we describe for the first time the use of the internal standard method in flow injection analysis (FIA) with amperometric detection. The method is based on the application of sequential potential pulses to the working electrode in an electrochemical flow cell. The sequence of potential pulses is selected in such a way that the analyte and internal standard compound are detected and monitored individually and independently at the same working electrode. This approach compensates for random errors associated with variations of flow rate, injection volume, ionic strength difference between standards and samples, and accidental insertion or formation of air bubbles in the carrier stream. In addition, this method can overcome the major drawback of amperometric detection using solid electrodes, which is gradual electrode passivation. To illustrate the potential of this method, the flow-injection amperometric detection of uric acid using [Fe(CN)6]3? as an internal standard (IS) is presented as an example. 相似文献
14.
Perceptions of sensation and pain in healthy people are believed to be the net result of sensory input and descending modulation from brainstem and cortical regions depending on emotional and cognitive factors. Here, the influence of attention on neural activity in the spinal cord during thermal sensory stimulation of the hand was investigated with functional magnetic resonance imaging by systematically varying the participants' attention focus across and within repeated studies. Attention states included (1) attention to the stimulus by rating the sensation and (2) attention away from the stimulus by performing various mental tasks of watching a movie and identifying characters, detecting the direction of coherently moving dots within a randomly moving visual field and answering mentally-challenging questions. Functional MRI results spanning the cervical spinal cord and brainstem consistently demonstrated that the attention state had a significant influence on the activity detected in the cervical spinal cord, as well as in brainstem regions involved with the descending analgesia system. These findings have important implications for the detection and study of pain, and improved characterization of the effects of injury or disease. 相似文献
15.
C. Urlacher J. Dumas J. Serughetti J. Mugnier M. Munoz 《Journal of Sol-Gel Science and Technology》1997,8(1-3):999-1005
ZrO2 waveguides are prepared by the sol-gel process from a solution containing zirconiumn-propoxide and acetylacetone in propanol-2. Structural characterizations are investigated for different annealing temperatures using suitable techniques including Waveguide Raman Spectroscopy, Electron Microscopy and Atomic Force Microscopy. Films are amorphous at 300°C and the pure ZrO2 tetragonal crystalline phase appears beyond 400°C. Crystallized films present a dense, uniform and polycrystalline structure made up by randomly oriented nanocrystallites, the diameter of which increases from 38 Å at 400°C to 53 Å at 600°C. Waveguides are at least monomode TE0 at 632.8 nm. At this wavelength, optical losses are about, 0.8±0.2dB/cm for amorphous layers and increase up to 2.5±0.4 dB/cm for 600°C heat-treated waveguides. 相似文献
16.
Lewis Acid Catalyzed Condensation–Cyclization Cascade: Direct Synthesis of Di/Trifluoromethyl‐1,2,3,4‐tetrahydroquinazolines
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Prof. Dr. G. K. Surya Prakash Dr. Attila Papp Socrates B. Munoz Nathan May John‐Paul Jones Prof. Dr. Ralf Haiges Prof. Dr. Pierre Mothé Esteves Dr. Thomas Mathew 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10170-10178
Condensed heterocycles such as quinazolines constitute the framework of many promising drugs. The great impact of the dramatic fluorine effect in pharmaceuticals prompted a great surge in the quest for fluorinated drug design resulting in over 20 % fluorine‐containing drugs in the market today. Therefore, finding an efficient and cost‐effective method for the direct synthesis of fluorine‐tagged quinazoline systems is of great significance in the pharmaceutical arena. For the first time, a one‐pot sequential condensation–cyclization reaction to form selectively the difluoro/trifluoromethylated tetrahydroquinazolines from simple components difluoro/trifluoroacetaldehyde hemiacetal and aromatic amines is reported. Our recent studies using difluoro/trifluoroacetaldehyde hemiacetal as simple and elegant difluoro/trifluoromethyl synthons and metal triflates such as gallium triflate as safe and stable Lewis acid catalysts led us to this direct synthesis protocol for the expedient and convenient synthesis of fluorinated quinazolines. DFT calculations at PCM/B3LYP/6‐31++G** were carried out for evaluating a possible reaction mechanism for this cyclization. According to the DFT calculations, product stereochemistry is thermodynamically driven, favoring the cis isomer as the major product, which is also confirmed experimentally. 相似文献
17.
A successful synthesis of novel diimides, namely anthracene diimide containing six-membered imide rings, with potential application in organic electronics is reported. The single crystal of 5a exhibits a close interplanar spacing of 3.45 ? between molecules in a stack. 相似文献
18.
Bernard Garrigues Aurelio Munoz Max Koenig Michel Sanchez Robert Wolf 《Tetrahedron》1977,33(6):635-643
New spirophosphoranes have been prepared by reaction of &alpha-aminoacids with tricoordinate phosphorus substrates. In one case, 1i, an equilibrium chain-cycle PIIIPv has been observed. 相似文献
19.
B. Blank A. Bey I. Matea J. Souin L. Audirac M. J. G. Borge G. Canchel P. Delahaye F. Delalee C. -E. Demonchy R. Domínguez-Reyes L. M. Fraile J. Giovinazzo Tran Trong Hui J. Huikari D. Lunney F. Munoz J. -L. Pedroza C. Plaisir L. Serani S. Sturm O. Tengblad F. Wenander 《The European Physical Journal A - Hadrons and Nuclei》2010,44(3):363-372
The half-lives of 38Ca and 39Ca have been measured at ISOLDE of CERN. The REXTRAP facility was used to prepare ultra-clean samples of radioactive nuclei for precision decay spectroscopy. 38Ca is one of the T z = - 1 , 0+ $ \rightarrow$ 0+ $ \beta$ -emitting nuclides used to determine the vector coupling constant of the weak interaction and the Vud quark-mixing matrix element. The result obtained, T 1/2 = 443.8(19) ms, is four times more precise than the average of previous measurements. For 39Ca , a half-life of T 1/2 = 860.7(10) ms is obtained, a result in agreement with the average value from the literature. 相似文献
20.
Solvignon P Liyanage N Chen JP Choi S Aniol K Averett T Boeglin W Camsonne A Cates GD Chang CC Chudakov E Craver B Cusanno F Deur A Dutta D Ent R Feuerbach R Frullani S Gao H Garibaldi F Gilman R Glashausser C Gorbenko V Hansen O Higinbotham DW Ibrahim H Jiang X Jones M Kelleher A Kelly J Keppel C Kim W Korsch W Kramer K Kumbartzki G Lerose JJ Lindgren R Ma B Margaziotis DJ Markowitz P McCormick K Meziani ZE Michaels R Moffit B Monaghan P Munoz Camacho C Paschke K Reitz B Saha A Sheyor R 《Physical review letters》2008,101(18):182502
We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_{1} of the neutron and 3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c);{2}. Global duality is observed for the spin-structure function g_{1} down to at least Q;{2}=1.8 (GeV/c);{2} in both targets. We have also formed the photon-nucleon asymmetry A1 in the resonance region for 3He and found no strong Q2 dependence above 2.2 (GeV/c);{2}. 相似文献