Quantifying Compound Aging Resistance at Service (Ambient) Temperatures

2009 ◽  
Vol 82 (1) ◽  
pp. 121-130
Author(s):  
Edward R. Terrill ◽  
James T. Lewis
Keyword(s):  
Oxygen Consumption ◽  
Service Life ◽  
Oxygen Uptake ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Tensile Elongation ◽  
Ambient Temperatures ◽  
Rubber Compounds ◽  
Consumption Rates ◽  
The Stability

Abstract Oxygen consumption rates were measured on natural rubber compounds with varying levels of a standard antioxidant package. The oxygen consumption rate measurements were performed at temperatures between 20 °C and 80 °C. The results elucidated the mechanism of antioxidants, including their pro-oxidant effects. The pro-oxidant effect dwindled with time. Integrated oxygen uptake results were calculated from repetitive oxygen consumption rate measurements. Integrated oxygen uptake time temperature master curves with empirical shift factors were combined with elongation-tobreak data to monitor the extent of aging. The stability of the compounds at service life temperatures could be quantified by combining the integrated oxygen uptake shift factors with the tensile elongation-to-break data; thereby to produce an elongation-to-break master curve at service life temperatures.

THE IN VITRO ACTION OF ACTH ON THE OXYGEN CONSUMPTION OF SLICES OF CATTLE ADRENAL CORTEX

1953 ◽  
Vol 9 (4) ◽  
pp. 379-390 ◽  
Author(s):  
M. REISS ◽  
EVA BRUMMEL ◽  
I. D. K. HALKERSTON ◽  
F. E. BADRICK ◽  
M. FENWICK
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Linear Relationship ◽  
Adrenal Cortex ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Biological Assay ◽  
Percentage Increase ◽  
Small Doses

A technique for measuring the action of small doses of ACTH on the oxygen consumption of slices of cattle adrenal cortex is described. The oxygen consumption rate of such slices in vitro is increased by ACTH. A linear relationship between logarithm of the dose of ACTH and the percentage increase in the rate of oxygen uptake is obtained with this method, and its suitability for biological assay purposes has been investigated. The question of the specificity of this action of ACTH is discussed.

scholarly journals 129 RESPIRATION ACTIVITY OF BOVINE EMBRYOS CULTURED IN SERUM-FREE AND SERUM-CONTAINING MEDIA

2005 ◽  
Vol 17 (2) ◽  
pp. 215 ◽  
Author(s):  
H. Abe ◽  
H. Shiku ◽  
S. Aoyagi ◽  
T. Matsue ◽  
H. Hoshi
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Consumption Rate ◽  
Embryo Quality ◽  
Consumption Rate ◽  
Developmental Stages ◽  
Culture Conditions ◽  
Bovine Embryos ◽  
Respiration Activity ◽  
Serum Free ◽  
Consumption Rates

Oxygen consumption is a ubiquitous parameter which can provide valuable information about metabolic mechanisms and embryo quality. Recently, we succeeded in non-invasively and quantitatively determining oxygen consumption of individual bovine embryos by the scanning electrochemical microscopy (SECM). The aim of this study was to assess by SECM the oxygen consumption of individual bovine embryos at different developmental stages cultured in serum-free and serum-supplemented media. Bovine oocytes were matured in IVMD101 medium [Research Institute for the Functional Peptides (IFP), Shimojo, Yamagata, Japan] and inseminated in BO-based medium. For serum-free culture, inseminated ooocytes were cultured to the blastocyst stage in IVD101 medium in an atmosphere of a low oxygen condition (5% CO2/5% O2/90% N2) at 38.5°C. For serum-supplemented culture, inseminated oocytes were cultured in HPM199 medium (IFP) supplemented with 5% calf serum (HPM199 + CS) in the presence of bovine cumulus/granulosa cells in a humidified atmosphere of 5% CO2 in air. Oxygen consumption by individual bovine embryos was non-invasively quantified by the SECM measuring system. Some embryos were prepared for transmission electron microscopy. The oxygen consumption rates are presented in the table. Oxygen consumption rates (F) of the single embryos were low from 2-cell to 8-cell stages (0.45–0.52 × 10−14 mol s−1). In serum-free culture, an increase in oxygen consumption rate was found at the morula (1.03 × 10−14 mol s−1) stage, and blastocysts showed an even higher oxygen consumption rate (1.86 × 10−14 mol s−1). On the other hand, the oxygen consumption of morulae and blastocysts produced in serum-supplemented medium was lower than that of embryos cultured in serum-free medium. Electron microscopic study demonstrated that many of the mitochondria of morulae and blastocycts cultured in HPM199 + CS medium were an immature form, indicating a correlation between respiration activity and development of mitochondria. These results suggest that the culture conditions affect the respiration activity of bovine embryos. The SECM procedures may have a wide application for judging embryo quality and culture conditions for embryos. Table 1. Oxygen consumption rates (F × 10−14 mol s−1) of the bovine embryos at various developmental stages

Sediment Microbial Activity in Acidic and Non-Acidic Lakes

1986 ◽  
Vol 21 (4) ◽  
pp. 560-571 ◽  
Author(s):  
B. K. Burnison ◽  
S. S. Rao ◽  
A. A. Jurkovic ◽  
D. J. Nuttley
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Glutamic Acid ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
The Other ◽  
Labeled Compounds ◽  
Acidic Lake ◽  
Consumption Rates ◽  
Plate Counts

Abstract The sediments from an acidic lake, a slightly acidic lake and a non-acidic lake were studied to determine the effect of lake acidification on organic biodegradation rates and bacterial numbers. Organic biodegradation was determined by mano-metric respirometry and mineralization of 14C-labeled compounds. All measurements were normalized to the same temperature (20°C). The oxygen consumption rate and bacterial numbers (based on spread plate counts) were greater in the non-acidic lake sediment throughout the study period. The oxygen consumption rates in the other lake sediments were 18-20 times lower and the bacterial numbers were 15 times lower than the non-acidic lake. In contrast, the results from experiment s using 14C-labeled glucose and glutamic acid often showed that the acidic sediments had twice the heterotrophic potential of the non-acidic sediments. 14C-labeled compounds should be used cautiously when measuring the acidification effects on organic matter decomposition.

Time course of aerobic recovery after contraction of rabbit papillary muscle

1987 ◽  
Vol 253 (2) ◽  
pp. H325-H332 ◽  
Author(s):  
F. Mast ◽  
G. Elzinga
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Time Constant ◽  
Oxygen Consumption Rate ◽  
Time Course ◽  
Consumption Rate ◽  
Oxygen Storage ◽  
Measuring System ◽  
Measured Time ◽  
Isometric Twitch

The time course of oxygen uptake after isometric twitch contractions of isolated rabbit papillary muscles was determined at 20 degrees C by continuous polarographic measurement of the partial pressure of oxygen in a 219-microliters glass chamber in which the fluid circulated rapidly. The response time of the oxygen-measuring system was characterized by a delay of 1.1 s and a time constant of 2.1 s after that delay. Depending on the stimulation frequency (0.125–1.0 Hz) the total amount of oxygen uptake for 120 twitches varied from 5.3 to 32.7 nmol/mg dry wt, and the steady-state oxygen consumption rate varied from 0.4 to 8.5 nmol X min-1 X mg dry wt-1. On the basis of a diffusion model we eliminated the effect of oxygen storage on the measured time course of oxygen consumption to determine the mitochondrial kinetics. We found a time constant of an average 19–22 s of mitochondrial off kinetics. By use of this time constant for the change in oxygen consumption rate after contraction, it can be estimated that 9–10% of the oxygen required to restore ATP levels is already taken up by the mitochondria during the twitch.

Techniques for Measurement of Oxygen Consumption Rates of Hepatocytes during Attachment and Post-Attachment

1996 ◽  
Vol 19 (1) ◽  
pp. 36-44 ◽  
Author(s):  
M. D. Smith ◽  
A. D. Smirthwaite ◽  
D. E. Cairns ◽  
R. B. Cousins ◽  
J. D. Gaylor
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Consumption Rate ◽  
Metabolic Pathways ◽  
Consumption Rate ◽  
Cultured Cells ◽  
Rat Hepatocytes ◽  
Flow Cell ◽  
Bioartificial Liver ◽  
Consumption Rates ◽  
Cytodex 3

Three techniques for measuring oxygen consumption rate (OCR) of cultured cells relevant to the development of bioartificial liver devices are reported. In an oxystat apparatus, HepG2 cells immobilised on Cytodex 3 microcarriers at a concentration of 106 cells ml-1 had a mean OCR of 0.7 nmol s-1/106 cells. The OCR decreased with increasing cell density, a characteristic previously reported for other cell lines. Rat hepatocytes immobilised on single collagen layers in a flow cell and challenged with ammonia had a mean OCR of 0.59 nmol s-1/106 cells. A novel two-compartment oxystat system was used to determine the OCR of rat hepatocytes during the attachment phase. OCR declined from 1.0 nmol s-1/106 immediately after seeding to 0.7 nmol s-1/106 cells at nine hours. The low OCR for HepG2 reflects loss of certain oxygen dependent metabolic pathways. The OCR measured for rat hepatocytes during and post-attachment are significantly higher than those reported elsewhere and have major implications for the development of bioartificial liver devices.

scholarly journals The oxygen consumption rates of different life stages of the endoparasitic nematode

2010 ◽  
Vol 29 (1) ◽  
pp. 20-29 ◽  
Author(s):  
Willie Van Aardt ◽  
Don Loots ◽  
Sonia Steenkamp
Keyword(s):  
Oxygen Consumption ◽  
Relative Humidity ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Secondary Infection ◽  
Life Stage ◽  
Life Stages ◽  
Adult Nematode ◽  
Respiration Physiology ◽  
Consumption Rates

The oxygen consumption rates of different life stages of the endoparasitic nematode, Pratylenchus zeae (Nematoda: Tylenchida) during non- and post-anhydrobiosisPratylenchus zeae, widely distributed in tropical and subtropical regions, is an endoparasite in roots of maize and other crop plants. The nematode is attracted to plant roots by CO2 and root exudates and feeds primarily on cells of the root cortex, making channels and openings where the eggs are deposited, with the result that secondary infection occurs due to bacteria and fungi. Nothing is known about the respiration physiology of this nematode and how it manages to survive during dry seasons. To measure the oxygen consumption rate (VO2 ) of individual P. zeae (less than half a millimeter long), a special measuring technique namely Cartesian diver micro-respirometry was applied. The Cartesian divers were machined from Perspex, and proved to be more accurate to measure VO2 compared with heavier glass divers used in similar experiments on free living nematodes. An accuracy of better than one nanoliter of oxygen consumed per hour was achieved with a single P. zeae inside the diver. Cartesian diver micro-respirometry measurements are based in principle on the manometric changes that occur in a fl otation tube in a manometer set-up when oxygen is consumed by P. zeae and CO2 from the animal is chemically absorbed. VO2 was measured for eggs (length: < 0.05 mm), larvae (length: 0.36 mm) and adults (length: 0.47 mm) before induction to anhydrobiosis. P. zeae from infected maize roots were extracted and exposed aseptically to in vitro maize root cultures in a grow cabinet at 50 % to 60% relative humidity at 28 ºC using eggs, larvae and adults. VO2 was also measured for post-anhydrobiotic eggs, larvae and adults by taking 50 individuals, eggs and larvae from the culture and placing them in Petri-dishes with 1% agar/water to dry out for 11 days at 28 ºC and 50% relative humidity. The VO2 was measured after the anhydrobiotic eggs, larvae and adults were re-hydrated for 12 hours in a high humidity atmosphere. The average VO2 value found for ten consecutive measurements during a 50 minute period of one adult using the diver technique was 32.8 nanoliter per hour. The differences between the ten VO2 values were less than 3.5 %, an indication of the accuracy of the diver measurements. The average VO2 values from ten measurements per life stage, expressed in nanolitres per hour per life stage of the pre-anhydro-biotes (eggs: 7.96; larva: 6.13; adult: 26.04) were compared with those of post-anhydrobiotes 12 hours after anhydrobiosis. The average VO2 values of the post-anhydrobiotes for the three life stages (egg: 19.34; larva: 14.17; adult: 32.86) were statistically signifi cantly higher in comparison with the pre-anhydrobiotes. The reasons for the difference are that high concentrations of metabolites, probably in the form of trehalose, accumulate during the anhydrobiosis stage to be utilized during the post-anhydrobiotic revival period. The oxygen consumption rate was also expressed in nanolitres per hour per microgram adult nematode after applying the following equation taken from the literature: M = a2 x b/16 x 1000 where M = mass (µg) of adult nematode; a = largest body width (µm); b = body length (µm). Using this equation it was found that one gram P. zeae uses 503 times more oxygen compared with one gram mammal the size of a cow. This high specifi c oxygen consumption rate (MO2 ) is a direct indication of the large metabolic damage this endoparasitic nematode can have on the metabolic substrates provided by the roots of the various plant crops it parasitize. 

scholarly journals Pengaruh konsentrasi sublethal endosulfan dan glifosat terhadap konsumsi oksigen kerang darah (anadara granosa)

DEPIK ◽  
2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Mikson M.D. Nalle ◽  
Ricky Gimin
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Consumption Rates ◽  
Animal Exposure ◽  
The Relationship ◽  
Anadara Granosa ◽  
Standard Animal

<p><strong><em>Abstract.</em></strong><em> The aims of the study were: (1) to test oxygen consumption of Anadara granosa under sub-lethal concentrations of endosulfan, (2) oxygen consumption under sub-lethal concentrations of glifosat and (3) oxygen consumption under mixture of endosulfan and glifosat. </em><em>Complete randomlizeddesign were applied on this experiment.</em><em> Initially, the oxygen consumption was standardised against animal’s dry flesh weight. Results showed that dry flesh weight afffected significantly the oxygen consumption.  The relationship between the two variables was formulated as  y = 0</em><em>.</em><em>217 + 0</em><em>.</em><em>243x.  Based on teh relationship, the oxygen consumption was reported as mg/l/hr of 1g standard animal.  Exposure of blood cockles to various sub-lethal concentrations of pesticides showed that the oxygen consumption rates reduced as the concentrations increased.  For endosulfan, the oxygen consumption rate decreased from </em><em>(</em><em>0</em><em>.</em><em>5325 ±</em><em> 0.1556)</em><em>mg/l/hr at 0</em><em>.</em><em>05 ppm to </em><em>(</em><em>0</em><em>.</em><em>2282 ±</em><em> 0.1552 ) </em><em>mg/l/hr at 0</em><em>.</em><em>5 ppm.  Increasing glifosat from 50 ppm to 200 ppm reduced the oxygen consumption from </em><em>(</em><em>0</em><em>.</em><em>3111±</em><em> 0.1811)</em><em>to </em><em>(</em><em>0</em><em>.</em><em>2449 ±</em><em> 0.2548)</em><em>mg/l/hr.</em><em> </em><em>Accordingly, the oxygen consumption decreased from </em><em>(</em><em>0</em><em>.</em><em>3376±</em><em> 0.972)</em><em>mg/l/hr to </em><em>(</em><em>0,2841±</em><em> 0.2057)</em><em>mg/l/hr</em><em> </em><em>when concentrations of mixture endosulfan + glifosat mixture increased from 0</em><em>.</em><em>005 + 50 ppm to 5 + 200 ppm.</em></p><p><strong><em>Keywords:</em></strong><em> pesticide</em><em>; </em><em>endosulfan</em><em>;</em><em> glyphosate</em><em>;</em><em> Anadara granosa</em><em>;</em><em> bioassay</em><em>;</em><em> oxygen consumption</em></p><p><strong> </strong></p><p><strong>Abstrak.</strong><strong> </strong>Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi sublethal endosulfan, glifosat, dan secara bersama-sama terhadap konsumsi oksigen kerang darah (<em>Anadara granosa</em>). Metode eksperimental dengan rancangan percobaan Rancangan Acak Lengkap (RAL) diterapkan dalam penelitian ini. Hasil penelitian menunjukan bahwa berat tubuh mempengaruhi laju konsumsi oksigen dengan hubungan <em>y = 0,217+0,243 x</em>, sehingga hasil pengukuran laju konsumsi oksigen dinyatakan sebagai mg/l/jam per 1 gram berat kering kerang standar. Pemaparan terhadap konsentrasi sublethal menunjukkan bahwa laju konsumsi oksigen menurun seiring dengan meningkatnya konsentrasi masing – masing pestisida maupun campurannya.  Untuk endosulfan, laju konsumsi oksigen menurun dari (0,5325± 0,1556) mg/l/jam pada 0,05 ppm menjadi (0,2282 ± 0,1552) mg/l/jam pada 5 ppm.  Untuk glifosat, laju konsumsi oksigen menurun dari (0,3111± 0,1811) mg/l/jam pada 50 ppm menjadi (0,2449 ± 0,2548) pada 200 ppm, sedangkan untuk campuran endosulfan + glifosat, laju konsumsi oksigen menurun dari (0,3376± 0,972)  mg/l/jam pada 0,005 + 50 ppm menjadi (0,2841± 0,2057) mg/l/jam pada 5 + 200 ppm.  Kisaran konsentrasi sublethal ini sangat mempengaruhi konsumsi oksigen kerang darah (<em>Anadara granosa</em>) yaitu laju konsumsi oksigen akan menurun jika konsentrasi endosulfan dan glifosat ditingkatkan. </p><strong><em>Kata kunci</em></strong><em>: pestisida; endosulfan; glifosat; Anadara granosa; bioassay; konsumsi oksigen</em>

scholarly journals Methods for Predicting More Confident Lifetimes of Seals in Air Environments

2000 ◽  
Vol 73 (2) ◽  
pp. 265-283 ◽  
Author(s):  
Kenneth T. Gillen ◽  
Mathias Celina ◽  
Michael R. Keenan
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Synergistic Effects ◽  
Tensile Elongation ◽  
Mechanical Strain ◽  
Extensive Study ◽  
Oxidation Reactions ◽  
Arrhenius Behavior ◽  
Degradation Rates

Abstract We have been working for many years to develop improved methods for predicting the lifetimes of polymers exposed to air environments and have recently turned our attention to seal materials. This paper describes an extensive study on a butyl material using elevated temperature compression stress—relaxation (CSR) techniques in combination with conventional oven aging exposures. The results initially indicated important synergistic effects when mechanical strain is combined with oven aging, as well as complex, non-Arrhenius behavior of the CSR results. By combining modeling and experiments, we show that diffusion-limited oxidation (DLO) anomalies dominate traditional CSR experiments. A new CSR approach allows us to eliminate DLO effects and recover Arrhenius behavior. Furthermore, the resulting CSR activation energy (Ea) from 125 to 70 °C is identical to the activation energies for the tensile elongation and for the oxygen consumption rate of unstrained material over similar temperature ranges. This strongly suggests that the same underlying oxidation reactions determine both the unstrained and strained degradation rates. We therefore utilize our ultrasensitive oxygen consumption rate approach down to 23 °C to show that the CSR Ea likely remains unchanged when extrapolated below 70 °C, allowing more confident room temperature lifetime predictions for the butyl seal.

Microbial efficiency in a meromictic reservoir

2008 ◽  
Vol 37 (2) ◽  
Author(s):  
Grażyna Mazurkiewicz-Boroń ◽  
Teresa Bednarz ◽  
Elżbieta Wilk-Woźniak
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Release Rate ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Metabolic Efficiency ◽  
Sulphur Compounds ◽  
Carbon Dioxide Release ◽  
Microbial Efficiency ◽  
Ion Contents

Microbial efficiency in a meromictic reservoirIndices of microbial efficiency (expressed as oxygen consumption and carbon dioxide release) were determined in the water column of the meromictic Piaseczno Reservoir (in an opencast sulphur mine), which is rich in sulphur compounds. Phytoplankton abundances were low in both the mixolimnion (up to 15 m depth) and monimolimnion (below 15 m depth). In summer and winter, carbon dioxide release was 3-fold and 5-fold higher, respectively, in the monimolimnion than in the mixolimnion. Laboratory enrichments of the sulphur substrate of the water resulted in a decrease in oxygen consumption rate of by about 42% in mixolimnion samples, and in the carbon dioxide release rate by about 69% in monimolimnion samples. Water temperature, pH and bivalent ion contents were of major importance in shaping the microbial metabolic efficiency in the mixolimnion, whilst in the monimolimnion these relationships were not evident.

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