Mass Spectrometric Characterization of Modifications to Angiotensin II by Lipid Peroxidation Products, 4-Oxo-2(E)-nonenal and 4-Hydroxy-2(E)-nonenal

2010 ◽  
Vol 23 (11) ◽  
pp. 1771-1785 ◽  
Author(s):  
Seon Hwa Lee ◽  
Ryo Takahashi ◽  
Takaaki Goto ◽  
Tomoyuki Oe
2020 ◽  
Vol 132 ◽  
pp. 258-267
Author(s):  
Naďa Wilhelmová ◽  
Hana Lukšanová ◽  
Martina Srbová ◽  
Jin K. Kim ◽  
Jiří Wilhelm

1991 ◽  
Author(s):  
K. Balasaunmugam ◽  
K. G. Owens ◽  
K. F. Hsueh ◽  
P. Hoontrakul ◽  
M. A. Olsen

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2123
Author(s):  
Makuachukwu F. Mbaegbu ◽  
Puspa L. Adhikari ◽  
Ipsita Gupta ◽  
Mathew Rowe

Determining gas compositions from live well fluids on a drilling rig is critical for real time formation evaluation. Development and utilization of a reliable mass spectrometric method to accurately characterize these live well fluids are always challenging due to lack of a robust and effectively selective instrument and procedure. The methods currently utilized need better calibration for the characterization of light hydrocarbons (C1–C6) at lower concentrations. The primary goal of this research is to develop and optimize a powerful and reliable analytical method to characterize live well fluid using a quadruple mass spectrometer (MS). The mass spectrometers currently being used in the field have issues with detection, spectra deconvolution, and quantification of analytes at lower concentrations (10–500 ppm), particularly for the lighter (<30 m/z) hydrocarbons. The objectives of the present study are thus to identify the detection issues, develop and optimize a better method, calibrate and QA/QC the MS, and validate the MS method in lab settings. In this study, we used two mass spectrometers to develop a selective and precise method to quantitatively analyze low level lighter analytes (C1–C6 hydrocarbons) with masses <75 m/z at concentrations 10–500 ppm. Our results suggest that proper mass selection like using base peaks with m/z 15, 26, 41, 43, 73, and 87, respectively, for methane, ethane, propane, butane, pentane, and hexane can help detect and accurately quantify hydrocarbons from gas streams. This optimized method in quadrupole mass spectrometer (QMS) will be invaluable for early characterization of the fluid components from a live hydrocarbon well in the field in real time.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 293-294
Author(s):  
Murat Baymishev ◽  
Sergey Eremin ◽  
Kirill Plemyashov ◽  
Khamidulla Baymishev ◽  
Igor Konopel’tsev ◽  
...  

Abstract The aim of the study was to determine the etiopathogenesis of reproductive dysfunction in highly productive cows. Studies were conducted on cows of black-motley breed, aged 3–5 lactations, with a live weight of 480–520 kg. Cows were divided into two groups. The first group included 20 cows effective inseminated after the first insemination. The second group included 17 cows that did not fertilize after the first insemination. Blood samples (n = 253) were taken from 4–7; 14–17; 24–34; 35–50; 88–95; 195–210 days of pregnancy; during the beginning of dry period (DP); 1–4 days before calving and on the first day after calving. The content of total serum lipids in pregnant animals was 15.8% higher compared to unfertilized animals. In non-pregnant cows, a decrease in free cholesterol (by 28.65%), especially in its ether-bound fraction (14.91%), indicates a lower synthetic function of the liver, which is confirmed by the low serum levels of vitamins A and E (a difference of 11.3 and 23.65%). The DP was characterized by a significant increase in the products of lipid peroxidation - malondialdehyde by 12–17%, diene and triene conjugates - by 10–15 and 8–15%, respectively, and 1–4 days before calving in cows, which subsequently had a pathological calving, in particular - retention of placenta (5 cows), were characterized by an increased content in the blood plasma of lipid peroxidation products. Thus, the difference in the number of dienes, trienes, and malondialdehyde products was 14.0, 12.0, and 23.5%, compared with animals without obstetric pathology. On the first day after calving, this difference increased even more. Cows with retention of placenta had a significantly higher level of lipid peroxidation products and were characterized by a predominance of oxidized products over the antiradical thiol disulfide and ascorbate systems restored in the antioxidant balance.


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