scholarly journals Cellular mechanisms of hypoxia development in the tissues of experimental animals under varying characteristics of vibration exposure

2019 ◽  
Vol 17 (3) ◽  
pp. 59-70
Author(s):  
Viktoriya V. Vorobieva ◽  
Petr D. Shabanov
Keyword(s):  
Kinetic Parameters ◽  
Oxidation Rate ◽  
Oxygen Sensor ◽  
Tissue Homogenate ◽  
Endogenous Respiration ◽  
Experimental Animals ◽  
Oxidation Rates ◽  
Metabolic States ◽  
Before And After ◽  
Endogenous Substrates

The aim of the work was to study the primary bioenergetic mechanisms of hypoxia formation in the myocardial tissue of experimental animals depending on the differentiated physical characteristics of vibration (frequency and duration) and their combination. The study of the functional states of native mitochondria in the composition of the tissue homogenate was carried out using the polarographic method and a galvanic-type closed-oxygen sensor in a 1-ml thermostatic cuvette in a salt incubation medium. The metabolic states of the mitochondria of the myocardium of experimental animals were modeled in vitro during the oxidation of endogenous substrates (before and after the administration of inhibitors of different links of the respiratory chain), with varying exogenous energy substrates (before and after the introduction of 2,4-DNP into the cell). In order to ensure synchronism of measurements in a short time, an incomplete cycle of metabolic states “endogenous respiration → rest → activity” was used. The results of multiple comparisons of variations in kinetic parameters revealed a reliable but multidirectional effect of the frequency of vibration on the rate of oxidation of substrates of the mitochondria of the heart of rabbits in different metabolic states. A change in the duration of exposure to vibration showed an increase in the oxidation rate of endogenous substrates and succinic acid at rest to 21–56 sessions by 17% and 24. 4%, respectively, while the oxidation rate of glutamate decreased to 56 sessions by 24. 5%. Comparison of the general variability of kinetic parameters with a combination of frequency and duration of vibration at different levels of variation showed that it was the interaction of factors that made the most important and significant contribution to the intergroup variability of oxidation rates of endogenous and exogenous substrates, identifying signs of the formation of bioenergetic hypoxia and allowing analysis of the primary physical transformation phenomena in the biological effect.

scholarly journals Tissue specific peculiarities of vibration-induced hypoxia of the rabbit heart, liver and kidney

2016 ◽  
Vol 14 (1) ◽  
pp. 46-62 ◽  
Author(s):  
Viktoriya V Vorobieva ◽  
Petr D Shabanov
Keyword(s):  
Succinic Acid ◽  
Energy Production ◽  
Pharmacological Action ◽  
Rabbit Heart ◽  
Tissue Type ◽  
Metabolic States ◽  
Before And After ◽  
Liver And Kidney ◽  
Endogenous Substrates

The purpose of the paper was experimental study of activity of energy production of the heart, liver and kidney after harmful action of general vibration with 8 and 44 Hz frequency. The functional state of native mitochondria in tissue homogenates was studied by polarographic method by means of closed oxygen device of halvanic type in thermostated cuvette of 1 ml volume in the salt medium of incubation. Metabolic states of mitochondria of the rabbit heart, liver and kidney were modeled in vitro in oxidation of endogenous substrates (before and after administration of inhibitors of different stages of breath chain) varying exogenous substrates (before and after administration of 2.4-DNP into the cell). In order to synchronize the changes in short time, the incomplete cycle of metabolic states “endogenous breath → rest → activity” was used. The velocity of mitochondrial oxidation of endogenous substrates was determined by tissue type, and was 16.3 ± 4.3, 5.2 ± 0.6 and 8.13 ± 1.4 ng-atom О min-1mg-1 protein for the heart, liver and kidney of intact animals respectively. In the heart, after high frequent vibration, the reduction of oxidation velocity of NAD-dependent substrates in rest and in active metabolic state of mitochondria was 43 % (р ≤ 0.05) and 30 % (р ≤ 0.01) respectively, while the velocity of oxidation for endogenous succinic acid increased by 77 % (р ≤ 0.05) to 21st session of vibration, then constantly decreasing to the end of vibration sessions. The same changes but in less degree were registerted in the liver and kidney. The systems of energy production of the heart and the studied parenchimatic organs were involved in reaction on vibration exposure and reacted typically by low energetic shift with hyperactivation of endogenous succinic acid system of oxidation and inhibition of NAD-depended part of the breath chain of mitochondria. Therefore, the study of bioenergetics mechanisms of hypoxia in different tissues allows to clear the molecular targets for pharmacological action by means of substrate antihypoxants.

Use of Lime in Recycling Asphalt

1996 ◽  
Vol 1535 (1) ◽  
pp. 117-123 ◽  
Author(s):  
M. L. Wisneski ◽  
J. M. Chaffin ◽  
R. R. Davison ◽  
J. A. Bullin ◽  
C. J. Glover
Keyword(s):  
Low Temperature ◽  
Kinetic Parameters ◽  
Research Program ◽  
Oxidation Rate ◽  
Supercritical Extraction ◽  
Oxidation Rates ◽  
Pressure Oxygen ◽  
Air Blowing ◽  
Highway Research ◽  
Lime Addition

Two Strategic Highway Research Program asphalts were aged in a pressure oxygen vessel (POV) with and without admixture of CaO and Ca(OH)2 at several concentrations. These same asphalts were then aged by low-temperature air blowing, and the resulting materials were softened by mixing with three recycling agents obtained by supercritical extraction of asphalts. These rejuvenated asphalts were mixed with varying amounts of CaO and aged in the POV. Oxidation rates and hardening were measured at various temperatures, and the resulting kinetic parameters were used to estimate hardening at road conditions. The hardening rate was always reduced by lime addition. The oxidation rate was sometimes reduced. The recycling agents alone reduced the hardening rates relative to those of the original asphalts, but the effect was further enhanced by CaO additions.

IMCL area density, but not IMCL utilization, is higher in women during moderate-intensity endurance exercise, compared with men

2007 ◽  
Vol 293 (6) ◽  
pp. R2336-R2342 ◽  
Author(s):  
Michaela C. Devries ◽  
Stuart A. Lowther ◽  
Alexander W. Glover ◽  
Mazen J. Hamadeh ◽  
Mark A. Tarnopolsky
Keyword(s):  
Lipid Oxidation ◽  
Endurance Exercise ◽  
Oxidation Rate ◽  
Respiratory Exchange Ratio ◽  
Exercise Bout ◽  
Moderate Intensity ◽  
Intramyocellular Lipid ◽  
Area Density ◽  
Net Use ◽  
Before And After

Women use more fat during endurance exercise as evidenced by a lower respiratory exchange ratio (RER). The contribution of intramyocellular lipid (IMCL) to lipid oxidation during endurance exercise is controversial, and studies investigating sex differences in IMCL utilization have found conflicting results. We determined the effect of sex on net IMCL use during an endurance exercise bout using an ultrastructural evaluation. Men ( n = 17) and women ( n = 19) completed 90-min cycling at 63% V̇o2peak. Biopsies were taken before and after exercise and fixed for electron microscopy to determine IMCL size, # IMCL/area, IMCL area density, and the % IMCL touching mitochondria. Women had a lower RER and carbohydrate oxidation rate and a higher lipid oxidation rate during exercise ( P < 0.05), compared with men. Women had a higher # IMCL/area and IMCL area density ( P < 0.05), compared with men. Women, but not men, had a higher % IMCL touching mitochondria postexercise ( P = 0.03). Exercise decreased IMCL area density ( P = 0.01), due to a decrease in the # IMCL/area ( P = 0.02). There was no sex difference in IMCL size or net use. In conclusion, women have higher IMCL area density compared with men, due to an increased # IMCL and not an increased IMCL size, as well as an increased % IMCL touching mitochondria postexercise. Endurance exercise resulted in a net decrease in IMCL density due to decreased number of IMCL, not decreased IMCL size, in both sexes.

Substrate oxidation during exercise in taekwondo athletes: impact of aerobic fitness status

2020 ◽  
Vol 16 (5) ◽  
pp. 371-376
Author(s):  
B. Taati ◽  
H. Rohani
Keyword(s):  
Aerobic Fitness ◽  
Oxidation Rate ◽  
Fat Oxidation ◽  
Potential Effect ◽  
Substrate Oxidation ◽  
Training Experience ◽  
Male Athletes ◽  
Fitness Level ◽  
Oxidation Rates ◽  
Maximal Fat Oxidation

The present study aimed to investigate the potential effect of different aerobic fitness levels on substrate oxidation in trained taekwondo athletes. 57 male athletes (age 21.10±7.79 years; VO2max 50.67±6.67 ml/kg/min) with regular weekly taekwondo training and training experience of at least three years completed a graded exercise test to exhaustion on a treadmill. Maximal fat oxidation (MFO), the exercise intensity related to MFO (Fatmax), and carbohydrate (CHO) oxidation rate were measured using indirect calorimetry methods. The athletes then were divided into a low (<50 ml/kg/min, n=18) and high (>50 ml/kg/min, n=39) VO2max group. The average MFO was higher in the high VO2max group than in the low VO2max group (0.46±0.19 vs 0.28±0.11 g/min; P<0.001). Although Fatmax tended toward higher values in the high VO2max group, no difference was observed between the groups (49.15±15.22 vs 42.42±12.37% of VO2max; P=0.18). It was also shown that the high VO2max group had a lower CHO oxidation rate and a higher fat oxidation rate at given exercise intensities. In conclusion, it seems that MFO and substrate oxidation rates in taekwondo athletes can be influenced by aerobic fitness level such that the athletes with higher VO2max appeared to use more fat as a fuel source for energy supply during a given exercise.

UK landfill methane emissions: Use of mobile plume measurements and carbon isotopic characterisation to reassess oxidation rates for open and closed sites 

2021 ◽  
Author(s):  
Semra Bakkaloglu ◽  
Dave Lowry ◽  
Rebecca Fisher ◽  
James France ◽  
Euan Nisbet
Keyword(s):  
Methane Oxidation ◽  
Mole Fraction ◽  
Oxidation Rate ◽  
Methane Emissions ◽  
Isotopic Signature ◽  
Oxidation Rates ◽  
Landfill Cover ◽  
Carbon Isotopic ◽  
Landfill Sites ◽  
The Impact

&lt;p&gt;Biological methane oxidation in landfill cover material can be characterised using stable isotopes. Methane oxidation fraction is calculated from the carbon isotopic signature of emitted CH&lt;sub&gt;4&lt;/sub&gt;, with enhanced microbial consumption of methane in the aerobic portion of the landfill cover indicated by a shift to less depleted isotopic values in the residual methane emitted to air. This study was performed at four southwest England landfill sites. Mobile mole fraction measurement at the four sites was coupled with Flexfoil bag sampling of air for high-precision isotope analysis. Gas well samples collected from the pipeline systems and downwind plume air samples were utilized to estimate methane oxidation rate for whole sites. This work was designed to assess the impact on carbon isotopic signature and oxidation rate as UK landfill practice and waste streams have changed in recent years.&lt;/p&gt;&lt;p&gt;The landfill status such as closed and active, seasonal variation, cap stripping and site closure impact on landfill isotopic signature and oxidation rate were evaluated. The isotopic signature of &lt;sup&gt;13&lt;/sup&gt;C-CH&lt;sub&gt;4&lt;/sub&gt; values of emissions varied between -60 and -54&amp;#8240;, with an averaged value of -57 +- 2&amp;#8240; for methane from closed and active landfill sites. Methane emissions from older, closed landfill sites were typically more enriched in &lt;sup&gt;13&lt;/sup&gt;C than emissions from active sites. This study found that the isotopic signature of &lt;sup&gt;13&lt;/sup&gt;C-CH&lt;sub&gt;4&lt;/sub&gt; of fugitive methane did not show a seasonal trend, and there was no plume observed from a partial cap stripping process to assess changes in &lt;sup&gt;13&lt;/sup&gt;C-CH&lt;sub&gt;4&lt;/sub&gt;&amp;#160;&amp;#160;isotopic signatures of emitted methane. Also, the closure of an active landfill cell caused a significant decrease in mole fraction of measured CH&lt;sub&gt;4&lt;/sub&gt;, which was less depleted &lt;sup&gt;13&lt;/sup&gt;C in the emitted plume due to a higher oxidation rate. Methane oxidation, estimated from the isotope fractionation, ranged from 3 to 27%, with mean values of 7% and 15% for active and closed landfills, respectively. These results indicate that the oxidation rate is highly site specific.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Ammonia Oxidizing Bacteria (AOB) kinetic parameters estimated using the actual maximum ammonia oxidation rate

2020 ◽  
Vol 147 ◽  
pp. 104876
Author(s):  
Alberto Mannucci ◽  
Cecilia Caretti ◽  
Iacopo Ducci ◽  
Claudio Lubello ◽  
Riccardo Gori ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Oxidation Rate ◽  
Ammonia Oxidation ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonia Oxidation Rate

Fundamentals of SiC-Based Device Processing

MRS Bulletin ◽  
1997 ◽  
Vol 22 (3) ◽  
pp. 42-49 ◽  
Author(s):  
M.R. Melloch ◽  
J.A. Cooper ◽  
D.J. Larkin
Keyword(s):  
Integrated Circuits ◽  
Metal Oxide ◽  
Oxidation Rate ◽  
Field Effect Transistors ◽  
Metal Oxide Semiconductor ◽  
Processing Technology ◽  
Oxide Semiconductor ◽  
Processing Technologies ◽  
Oxidation Rates ◽  
Polysilicon Gate

Since the commercial availability of SiC substrates in 1990, SiC processing technology has advanced rapidly. There have been demonstrations of monolithic digital and analogue integrated circuits, complementary metal-oxide-semiconductor (CMOS) analog integrated circuits, nonvolatile random-access memories, self-aligned polysilicon-gate metal-oxide-semiconductor field-effect transistors (MOSFETs), and buried-channel polysilicon-gate charge-coupled devices (CCDs). In this article, we review processing technologies for SiC.OxidationA beneficial feature of SiC processing technology is that SiC can be thermally oxidized to form SiO2. When a thermal oxide of thickness x is grown, 0.5x of the SiC surface is consumed, and the excess carbon leaves the sample as CO. Shown in Figure 1 are the oxide thicknesses as a function of time for the Si-face and the C-face of 6H-SiC, and for Si. The oxidation rates are considerably lower for SiC than for Si. The oxidation rate of the C-face of 6H-SiC is considerably greater than that of the Si-face. Hornetz et al. have shown that the reason for the slower oxidation rate of the Si-face is due to a 1-nm Si4C4−xO2 (x < 2) layer that forms between the SiC and the SiO2 during oxidation of the Si-face. When oxidizing the Si-face, the Si atoms oxidize first, which inhibits the oxidation of the underlying C atoms that are 0.063 nm below the Si atoms. When oxidizing the C-face, the C atoms readily oxidize first to form CO, with no formation of the Si4C4−xO2 layer for temperatures above 1000°C.

scholarly journals Effect of N-Methylacetamide Concentration and Thawing Rate on Chicken Sperm Quality after Cryopreservation

Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 824
Author(s):  
Fabio Mosca ◽  
Luisa Zaniboni ◽  
Ahmad Abdel Sayed ◽  
Nicolaia Iaffaldano ◽  
Dominga Soglia ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Kinetic Parameters ◽  
Sperm Quality ◽  
Membrane Integrity ◽  
Motile Sperm ◽  
Cell Membrane Integrity ◽  
Before And After ◽  
Freezing Procedure ◽  
Thawing Rate

In seeking alternative cryoprotectants to glycerol for a reference chicken semen freezing procedure, the aim of the present study was to compare the effect of two concentrations of N-Methylacetamide (MA) and two thawing rates on the quality of frozen-thawed semen. Semen samples were diluted in Lake pre-freezing extender, including 0.1 M trehalose in presence of 6% or 9% MA, loaded into straws, frozen in nitrogen vapors, and stored in liquid nitrogen. The following thawing treatments were used: 5 °C for 100 s and 38 °C for 30 s. Sperm quality (cell membrane integrity, motility and kinetic parameters) was assessed before and after cryopreservation. The decrease of MA concentration from 9 to 6% improved sperm quality after freezing/thawing and this effect was dependent on thawing temperature. Decreasing the MA concentration from 9 to 6% improved the proportion of undamaged membrane, motile, and progressive motile sperm recovered after thawing at 5 °C for 100 s; in contrast, no effect of the MA concentration was observed thawing at 38 °C for 30 s. Therefore, the treatment with 6% MA and thawing at 5 °C for 100 s has given the best cryoprotective action. These results contribute to improve the efficacy of the current chicken semen cryopreservation procedures.

scholarly journals Comparison of the Postprandial Metabolic Fate of U- 13 C Stearic Acid and U- 13 C Oleic Acid in Postmenopausal Women

2020 ◽  
Vol 40 (12) ◽  
pp. 2953-2964
Author(s):  
Jose Rodríguez-Morató ◽  
Jean Galluccio ◽  
Gregory G. Dolnikowski ◽  
Alice H. Lichtenstein ◽  
Nirupa R. Matthan
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acid ◽  
Postmenopausal Women ◽  
Oxidation Rate ◽  
Ldl Cholesterol ◽  
Area Under The Curve ◽  
Density Lipoprotein ◽  
Plasma Metabolites ◽  
Acid Oxidation ◽  
Oxidation Rates

Objective: Compare the postprandial fatty acid metabolism of isotopically labeled stearate (U- 13 C18:0) and oleate (U- 13 C18:1). Approach and Results: In conjunction with a randomized-controlled crossover trial, 6 hypercholesterolemic postmenopausal women (≥50 years; body mass index: 25.6±3.0 kg/m 2 ; LDL [low-density lipoprotein]-cholesterol ≥110 mg/dL) consumed isocaloric diets enriched in 18:0 or 18:1 (10%–15% E) for 5 weeks each. On day 1 of week 5, following a 12-hour fast, participants receive their experimental diet divided into 13 hourly meals beginning at 8 am . U- 13 C18:0 or U- 13 C18:1 was incorporated into the 1:00 pm meal (1.0 mg/kg body weight). Serial blood and breath samples were collected over 12 hours and fasting samples at 24 and 48 hours. Plasma and lipid subfraction fatty acid profiles were assessed by gas chromatography-flame ionization detector, isotope-enrichment by liquid chromatography time-of-flight mass spectrometry, and fatty acid oxidation rate (expired 13 CO 2 ) by isotope ratio mass spectrometry. Both diets resulted in similar plasma LDL-cholesterol concentrations. Kinetic curves showed that U- 13 C18:0 had a higher plasma area under the curve (66%), lower plasma clearance rate (−46%), and a lower cumulative oxidation rate (−34%) than U- 13 C18:1. Three labeled plasma metabolites of U- 13 C18:0 were detected: 13 C16:0, 13 C16:1, and 13 C18:1. No plasma metabolites of U- 13 C18:1 were detected within the study time-frame. Higher incorporation of 18:0 in cholesteryl ester and triglyceride fractions was observed on the 18:0 compared with the 18:1 diet. Conclusions: The neutrality of 18:0 on plasma LDL-cholesterol concentrations is not attributable to a single factor. Compared with 18:1, 18:0 had higher plasma area under the curve because of lower clearance and oxidation rates, underwent both a direct and a multistage conversion to 18:1, and was preferentially incorporated into cholesteryl esters and triglycerides.

Sign in / Sign up

Export Citation Format

Share Document