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Popescu C. Voicu I. Alexandrescu R. Morjan I. Dumitras D. Popescu M. Fatu D. 《Journal of Thermal Analysis and Calorimetry》1999,56(1):183-189
This paper reports on the synthesis of various iron oxides by the IR laser processing of different iron salts. X-ray diffraction
techniques were used to characterize the reaction products. Some differences in terms of crystallite size and isotropy between
these oxides and those obtained from the same salt by thermal means are described and explained.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Popa C. Bratu A. M. Matei C. Cernat R. Popescu A. Dumitras D. C. 《Laser Physics》2011,21(7):1336-1342
The hypothesis that blood, urine and other body fluids and tissues can be sampled and analyzed to produce clinical information
for disease diagnosis or therapy monitoring is the basis of modern clinical diagnosis and medical practice. The analysis of
breath air has major advantages because it is a non-invasive method, represents minimal risk to personnel collecting the samples
and can be often sampled. Breath air samples from the human subjects were collected using aluminized bags from QuinTron and
analyzed using the laser photoacoustic spectroscopy (LPAS) technique. LPAS is used to detect traces of ethylene in breath
air resulting from lipid peroxidation in lung epithelium following the radiotherapy and also traces of ammonia from patients
subjected to hemodialysis for treatment of renal failure. In the case of patients affected by cancer and treated by external
radiotherapy, all measurements were done at 10P(14) CO2 laser line, where the ethylene absorption coefficient has the largest value (30.4 cm−1 atm−1), whereas for patients affected by renal failure and treated by standard dialysis, all measurements were performed at 9R(30)
CO2 laser line, where the ammonia absorption coefficient has the maximum value of 57 cm−1 atm−1. The levels of ethylene and ammonia in exhaled air, from patients with cancer and renal failure, respectively, were measured
and compared with breath air contents from healthy humans. Human gas biomarkers were measured at sub-ppb (parts per billion)
concentration sensitivities. It has been demonstrated that LPAS technique will play an important role in the future of exhaled
breath air analysis. The key attributes of this technique are sensitivity, selectivity, fast and real time response, as well
as its simplicity. 相似文献
3.
C. Popa D. C. A. Dutu R. Cernat C. Matei A. M. Bratu S. Banita D. C. Dumitras 《Applied physics. B, Lasers and optics》2011,105(3):669-674
The application of laser photoacoustic spectroscopy (LPAS) for fast and precise measurements of breath biomarkers has opened
up new promises for monitoring and diagnostics in recent years, especially because breath test is a non-invasive method, safe,
rapid and acceptable to patients. Our study involved assessment of breath ethylene and breath ammonia levels in patients with
renal failure receiving haemodialysis (HD) treatment. Breath samples from healthy subjects and from patients with renal failure
were collected using chemically inert aluminized bags and were subsequently analyzed using the LPAS technique. We have found
out that the composition of exhaled breath in patients with renal failure contains not only ethylene, but also ammonia and
gives valuable information for determining efficacy and endpoint of HD. 相似文献
4.
Dumitras D. C. Dutu D. C. Matei C. Cernat R. Banita S. Patachia M. Bratu A. M. Petrus M. Popa C. 《Laser Physics》2011,21(4):796-800
Photoacoustic spectroscopy represents a powerful technique for measuring extremely low absorptions independent of the path
length and offers a degree of parameter control that cannot be attained by other methods. We report precise measurements of
the ammonia absorption coefficients at the CO2 laser wavelengths by using a photoacoustic (PA) cell in an extracavity configuration and we compare our results with other
values reported in the literature. Ammonia presents a clear fingerprint spectrum and high absorption strengths in the CO2 wavelengths region. Because more than 250 molecular gases of environmental concern for atmospheric, industrial, medical,
military, and scientific spheres exhibit strong absorption bands in the region 9.2–10.8 μm, we have chosen a frequency tunable
CO2 laser. In the present work, ammonia absorption coefficients were measured at both branches of the CO2 laser lines by using a calibrated mixture of 10 ppm NH3 in N2. We found the maximum absorption in the 9 μm region, at 9R(30) line of the CO2 laser. One of the applications based on the ammonia absorption coefficients is used to measure the ammonia levels in exhaled
human breath. This can be used to determine the exact time necessary at every session for an optimal degree of dialysis at
patients with end-stage renal disease. 相似文献
5.
M. Ittu Zugrav A. Dumitrica A. Dumitras N. Comaniciu 《Crystal Research and Technology》1982,17(4):475-480
The deuterated homologue of potassium dihydrogen phosphate crystals (DKDP) was grown by a modified transport method. Experimental results concerning electrooptic characteristics of these single crystals used in construction of a Q-switch and a four-crystals modulator are presented. An infrared extension of KURTZ -ROBINSON model electrooptic effect is also given. 相似文献
6.
Annamaria Jakab Serge Winter Marc Raccuglia Frank Picard Swati Dumitras Ralph Woessner Sanket Mistry Jayraj Chudasama Swati Guttikar Olivier Kretz 《Analytical and bioanalytical chemistry》2013,405(1):215-223
A simple, sensitive, and selective liquid chromatography/tandem mass spectrometry method was validated for the identification and quantification of mavoglurant (AFQ056) in human plasma. The chromatographic separation was performed using a Cosmosil 5 C18 (150?×?4.6 mm, 5 μm) column at 40?±?0.5 °C with a mobile phase consisting of acetic acid in water (0.1 %, v/v)/methanol (10:90, v/v) with a flow rate of 1.0 mL/min followed by quantification with tandem mass spectrometry, operating with electrospray ionization in positive ion mode and applying multiple reaction monitoring. The validated method described in this paper presents high absolute recovery with precision and accuracy meeting the acceptance criteria. The method was precise and accurate for 2- and 10-fold dilution of samples. The method was validated using sodium heparin as specific anticoagulant, and the anticoagulant effect was tested by lithium heparin and K3EDTA. The method was successfully cross-validated between two bioanalytical sites. The method was specific for mavoglurant within the given criteria for acceptance (apparent peak area at the retention time of mavoglurant in zero samples was less than 20 % compared with the mean peak area at LLOQ) in human plasma. The method was fully validated for the quantitative determination of mavoglurant in human plasma between the range of 2.00 and 2,500 ng/mL. 相似文献
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