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321.
Development and validation of a selective and robust LC-MS/MS method for quantifying amlodipine in human plasma 总被引:1,自引:0,他引:1
Massaroti P Moraes LA Marchioretto MA Cassiano NM Bernasconi G Calafatti SA Barros FA Meurer EC Pedrazzoli J 《Analytical and bioanalytical chemistry》2005,382(4):1049-1054
A liquid chromatographic–tandem mass spectrometric method (LC-MS/MS) for quantifying amlodipine in human plasma was developed and validated. Sample preparation was based on liquid–liquid extraction using NaOH and a mixture of ethyl acetate/hexane (80/20; v/v). Chromatography was performed on a C-18 analytical column and the retention times were 1.9 and 3.0 min for amlodipine and nimodipine (internal standard), respectively. The ionization was optimized using ESI(+) and enhanced selectivity was achieved using tandem mass spectrometric analysis via two MRM functions, 409238 and 418343 for amlodipine and nimodipine. The calibration curve ranged from 0.2 to 20.0 ng/mL. The inter-day precision and accuracy and the relative standard deviation (RSD) were <15%. The analyte was shown to be stable over the timescale of the whole procedure. The robustness of the method was demonstrated by the good reproducibility of the results obtained during the analysis of clinical samples. 相似文献
322.
L.F.L. Costa J.C.S. Moraes F.C. Cruz R.C. Viscovini D. Pereira 《Applied physics. B, Lasers and optics》2007,86(4):703-706
We report 12 new THz (far-infrared) laser lines from methanol (CH3OH), ranging from 58.1 μm (5.2 THz) to 624.6 μm (0.5 THz). A 13CO2 laser of wide tunability (110 MHz) has been used for optical pumping, allowing access to previously unexplored spectral regions.
Optoacoustic absorption spectra were used as a guide to search for new THz laser lines, which have been characterized in wavelength,
polarization, offset, relative intensity, and optimum operation pressure. For 20 laser lines previously observed, we have
measured the absorption offset with respect to the 13CO2 laser line center.
PACS 33.20.Ea; 33.20.Vq; 33.80.-b 相似文献
323.
Miguel Elias M. Campista Igor M. Moraes Pedro Miguel Esposito Aurelio Amodei Jr. Daniel De O. Cunha Luis Henrique M.K. Costa Otto Carlos M.B. Duarte 《Communications Magazine, IEEE》2007,45(1):136-143
The upcoming terrestrial digital television technology brings a new class of services to traditional TV sets. A set-top box may, for example, access the Internet and send email. The interactive return channel makes these new services possible. This channel allows TV viewers to interact by sending data back to the TV broadcaster. In this article we analyze the viability of a wireless ad hoc network to implement the return channel. For this purpose, an ad hoc network is a low-cost and flexible solution. We evaluate the performance of an ad hoc return channel using the IEEE 802.11 wireless technology for different Brazilian geographical scenarios. The results show that ad hoc networking is a promising solution for the return channel of Brazilian interactive digital TV 相似文献
324.
Letícia R. Teixeira Rubén D. Sinisterra Rafael P. Vieira Aline Scarlatelli-Lima Márcio F.D. Moraes Maria Carolina Doretto Ângelo M. Denadai Heloisa Beraldo 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):133-138
A non-hygroscopic pharmaceutical composition was obtained following a host-guest strategy that used the anticonvulsant drug
sodium valproate (VA) and α-cyclodextrin. The pharmaceutical composition was fully characterized by thermal analyses (TG/DTG,
DSC), X-ray powder diffraction and by 1H, 13C, hydrogen relaxation times (T1) and 2D-ROESY NMR techniques. Isothermal titration calorimetry (ITC) was used to determine the VA:α-CD 1:1 stoichiometry
as well as to calculate the equilibrium constant (K) and thermodynamic energies of interaction (ΔGo, ΔHo and TΔSo). 相似文献
325.
The molar single ion activity coefficients associated with hydrogen, copper(II), cadmium(II) and lead(II) ions were determined at 25 degrees C and ionic strengths between 0.100 and 3.00 M (NaClO4), whereas for acetate the ionic strengths were fixed between 0.300 and 2.00 M, held with the same inert electrolyte. The investigation was carried out potentiometrically by using proton-sensitive glass, copper, cadmium and lead ion-selective electrodes and a second-class Hg|Hg2(CH3COO)2 electrode. It was found that the activity coefficients of these ions (y(i)) can be assessed through the following empirical equations: log y(H) = -0.542I(0.5) + 0.451I; log y(Cu) = -1.249I(0.5) + 0.912I; log y(Cd) = -0.829I(0.5) + 0.448I(1.5); log y(Pb) = -0.404I(0.5) + 0.117I(2); and log y(Ac) = 0.0370I 相似文献
326.
Arthur A. Zopellaro Soares Juan Lucas Vieira Silvio E. Quincozes Vinicius C. Ferreira Luana M. Uchôa Yona Lopes Diego Passos Natalia C. Fernandes Igor Monteiro Moraes Débora Muchaluat-Saade Célio Albuquerque 《International Journal of Network Management》2021,31(3):e2112
With the popularization of the smart grid paradigm, substation automation technology has gradually been upgraded with additional processing and communication capabilities within control and protection devices. Hence, the research community is pressured to find new, efficient, and reliable communication solutions for such a scenario. That task is complicated by the stringent temporal requirements defined by the International Electrotechnical Commission (IEC) 61850 standard for power system communication comprising teleprotection schemes. Further compounding the issue is the critical nature of the power grid, in which availability is definitely a strong requirement. Software-defined networking (SDN) may provide powerful tools to fulfill those requirements at acceptable costs. As such, this paper surveys and compares several available SDN controllers and their applicability to the teleprotection scenario. It further evaluates controllers in terms of capacity and resilience through experiments in an emulated environment. 相似文献
327.
E. M. Telles J. C. S. Moraes A. Scalabrin D. Pereira A. Moretti F. Strumia 《Applied physics. B, Lasers and optics》1991,52(1):36-41
In this work we report new FIR laser lines from CD3OD optically pumped by a CO2 waveguide laser. The wide tunability of this laser (290 MHz) makes it possible to pump absorption lines with large frequency offset relative to the CO2 laser line center, which are not possible by using conventional CO2 lasers. As a consequence 19 new laser lines have been discovered, ranging from 38.0 m to 455.2 m in wavelength. For all lines, precise frequency offset measurements between the CO2 line center and the center of the absorber CD3OD line were performed using the transferred Lamb-dip technique. We also present direct Doppler-free offset measurements of infrared absorption, obtained within the FIR laser cavity itself, using optoacoustic detection.Work supported by FAPESP, CNPq, FAP-Brasil and CNR-Italy 相似文献
328.
Ion-emission characteristics of a single-filament surface-ionization source for uranium are described. It is shown that a graphite coating over uranium samples enhances reduction of oxides to U+ and improves quantitative performance. Results obtained for uranium in several rock samples are in reasonable agreement with results reported by others. 相似文献
329.
A.P.A. Moraes R. Romano A.G. Souza Filho P.T.C. Freire J. Mendes Filho O.L. Alves 《Vibrational Spectroscopy》2006,40(2):209-212
We have measured Raman and infrared spectra of α-Ge(HPO4)2·H2O compound at room temperature. The analysis of vibrational modes indicated the presence of two non-equivalent HPO42− units in agreement with 31P nuclear magnetic resonance measurements. A tentative assignment of all the observed modes is proposed based on the previous works reported for other hydrogenphosphate-based compounds. 相似文献
330.
Ifa DR Falci M Moraes ME Bezerra FA Moraes MO de Nucci G 《Journal of mass spectrometry : JMS》2001,36(2):188-194
A rapid, sensitive and specific analytical method was developed and validated to quantify gabapentin in human plasma using acetaminophen as an internal standard. The method employs a single plasma protein precipitation. The analytes are chromatographed on a C4 reversed-phase chromatographic column and analyzed by mass spectrometry in the multiple reaction monitoring (MRM) mode. The method has a chromatographic run time of 4 min and a linear calibration curve over the range 50-10 000 ng x ml(-1) (r > 0.999). The between-run precision, based on the relative standard deviation for replicate quality controls, was < or = 4.8 % (200 ng x ml(-1)), 6.0% (1000 ng x ml(-1)) and 4.4% (5000 ng x ml(-1)). The between-run accuracy was +/-2.6, 4.4 and 0.5% for the above-mentioned concentrations, respectively. This method was employed in a bioequivalence study of two gabentin capsule formulations (Progresse from Biosintética, Brazil, as a test formulation, and Neurotin from Parke-Davis, as a reference formulation) in 24 healthy volunteers of both sexes who received a single 300 mg dose of each formulation. The study was conducted using an open, randomized, two-period crossover design with a 7-day washout interval. The 90% confidence interval (CI) of the individual ratio geometric mean for Progresse/Neurotin was 87.9-115.6% for AUC(0-36 h) and 88.6-111.7% for Cmax. Since both 90% CI for AUC(0-36 h) and Cmax were included in the 80-125% interval proposed by the US Food and Drug Administration, Progresse was considered bioequivalent to Neurotin according to both the rate and extent of absorption. 相似文献