Factors affecting the onset and termination of respiration in the salamander, Amphiuma tridactylum

1971 ◽  
Vol 49 (9) ◽  
pp. 1231-1237 ◽  
Author(s):  
Daniel P. Toews
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Control ◽  
Dorsal Aorta ◽  
Free Swimming ◽  
Detection Mechanism ◽  
Factors Affecting ◽  
Oxygen Tensions ◽  
High Concentrations ◽  
Short Time ◽  
Very High

Respiratory control was studied in 22 intact, free-swimming Amphiuma tridactylum. Termination of inspiration was shown to be controlled by a volume-detection mechanism. Animals were shown to continue the breathing process if air was simultaneously removed from the lungs through a lung cannula. Injections of nitrogen into the lungs terminated inspiration for a short time but breathing occurred a short time after. Carbon dioxide injected into the lungs in doses 3-5 times the concentration normally present was removed from the lungs rapidly and did not result in the onset of breathing if the oxygen tensions were sufficiently high. Very high concentrations of carbon dioxide in the lungs resulted in a shortening of time between breaths. Increased levels of carbon dioxide in the dorsal aorta did not bring about the breathing response. Removal of oxygen from the lungs brought about a rapid breathing response. The presence of an oxygen chemoreceptor was postulated as a mechanism for controlling breathing in Amphiuma.

Gas Tensions in the Lungs and Major Blood Vessels of the Urodele Amphibian, Amphiuma Tridactylum

1971 ◽  
Vol 55 (1) ◽  
pp. 47-61
Author(s):  
DANIEL P. TOEWS ◽  
G. SHELTON ◽  
D. J. RANDALL
Keyword(s):  
Carbon Dioxide ◽  
Pulmonary Artery ◽  
Inferior Vena Cava ◽  
Blood Vessels ◽  
Pulmonary Vein ◽  
Oxygen Tension ◽  
Inferior Vena ◽  
Vena Cava ◽  
Dorsal Aorta ◽  
Oxygen Tensions

1. Oxygen and carbon dioxide tensions were determined in the lungs and in blood from the dorsal aorta, pulmonary vein, pulmonary artery and inferior vena cava in the intact, free swimming, Amphiuma. At 15° C this animal was submerged for a large part of the time and surfaced briefly to breathe at variable time intervals, the mean period being 45 min. 2. Oxygen tensions in the lungs and in all blood vessels oscillated with the breathing cycles, falling gradually during the period of submersion and rising rapidly after the animal breathed. The absolute level of oxygen tension did not appear to constitute the effective signal beginning or ending a series of breathing movements. 3. A small oxygen gradient existed between lungs and blood in the pulmonary vein immediately after a breath. The gradient increased in size as an animal remained submerged due, it is suggested, to lung vasoconstriction increasing the transfer factor. 4. Blood in the dorsal aorta had a lower oxygen tension than that in the pulmonary vein. A right-to-left shunt occurred as blood moved through the heart. The degree of shunting increased as the animal remained submerged and pulmonary vasoconstriction occurred. Left-to-right shunt was relatively insignificant since oxygen tensions in the inferior vena cava and pulmonary artery were very similar. 5. Carbon dioxide tensions were relatively constant during the breathing-diving cycle since Amphiuma removed almost all of this gas through the skin.

scholarly journals Survival and Behaviour of Ammocoetes at Low Oxygen Tensions

1970 ◽  
Vol 53 (1) ◽  
pp. 59-73 ◽  
Author(s):  
I. C. POTTER ◽  
B. J. HILL ◽  
SUSAN GENTLEMAN
Keyword(s):  
Carbon Dioxide ◽  
Haemoglobin Concentration ◽  
Low Oxygen ◽  
Lethal Level ◽  
Partial Pressures ◽  
Oxygen Conditions ◽  
Oxygen Tensions ◽  
High Concentrations ◽  
Ph Range ◽  
High Carbon Dioxide

1. Survival and behaviour studies were made on ammocoetes subjected to water of various tensions of oxygen and carbon dioxide. 2. Ammocoetes can tolerate, for at least 4 days, oxygen tensions as low as 7-10 mmHg at 5 °C, 12-16 mmHg at 15.5 °C and between 13-16 and 19-21 mmHg at 22.5 °C. A limited ability to acclimate to low oxygen tensions was found in some animals. 3. A characteristic emergence behaviour is evoked by low partial pressures of oxygen that approach the lethal level and by high concentrations of carbon dioxide. 4. Ammocoetes respond to low oxygen and high carbon dioxide by an increase in the rate and amplitude of beating of the branchial basket. This increase is maintained in animals able to survive at low oxygen tensions. 5. A high affinity of the blood for oxygen is evident from oxygen equilibrium curves determined on erythrocytes suspension. There was an insignificant Bohr effect at 15.5 °C in the pH range 7.68-6.70, although a change occurred in the n value. 6. Haemoglobin concentration, haematocrit and oxygen equilibria suggest that the characteristics of the blood contribute significantly to the ability of ammocoetes to survive in low oxygen conditions.

Factors Affecting the Application of Low-Volume Sprays

1964 ◽  
Vol 68 (644) ◽  
pp. 535-539 ◽  
Author(s):  
R. C. Amsden
Keyword(s):  
Surface Tension ◽  
Critical Value ◽  
Factors Affecting ◽  
Application Rates ◽  
Low Volume ◽  
High Concentrations ◽  
Rate Of Evaporation ◽  
Biological Performance ◽  
The Tropics ◽  
Very High

SummaryAerial crop spraying necessitates the lowest feasible application rates to minimise costs. The low volumes now being used in the Tropics and in this country often require very high concentrations of active ingredient. Most agricultural sprays are formulated for use in 10-100 gallons per acre. When the same weight of chemical is applied in one gallon or less per acre any one of hitherto disregarded factors, such as surface tension, rate of evaporation, density, viscosity, dynamic catch, and so on, may unexpectedly reach a critical value. An understanding of the limits of these factors is essential for the diagnosis or prevention of faulty biological performance.

scholarly journals Synergism Between Phosphine (PH3) and Carbon Dioxide (CO2): Implications for Managing PH3 Resistance in Rusty Grain Beetle (Laemophloeidae: Coleoptera)

2020 ◽  
Vol 113 (4) ◽  
pp. 1999-2006
Author(s):  
Myrna Constantin ◽  
Rajeswaran Jagadeesan ◽  
Kerri Chandra ◽  
Paul Ebert ◽  
Manoj K Nayak
Keyword(s):  
Carbon Dioxide ◽  
Reference Strain ◽  
Fold Increase ◽  
Stored Grain ◽  
Response Data ◽  
Alternative Approach ◽  
Mortality Response ◽  
High Concentrations ◽  
Carbon Dioxide Co2 ◽  
Very High

Abstract Strong resistance to phosphine (PH3) in the rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Laemophloeidae: Coleoptera) poses a serious risk to stored-grain biosecurity. Resistant populations hold risk of surviving in PH3 fumigation, particularly in storage structure that limits achieving very high concentrations of PH3, demanding the need for alternative fumigation strategies. Cofumigation with PH3 and carbon dioxide (CO2) is one alternative approach that has the potential to be used widely. CO2 fumigation of adults of strongly PH3-resistant reference strain of C. ferrugineus, for 48 h, showed that the effective concentration (LC50) of CO2 was 30.99%. This 30% level of CO2 in combination with PH3 decreased the LC50 of PH3 from 6.7 mg/liter to 0.84 mg/liter, an eightfold increase in PH3 efficacy relative to PH3 fumigation in normal air. The LC99.9 decreased from 16.2 mg/liter to 5.8 mg/liter, a 2.8-fold increase in PH3 efficacy. Comparison of mortality response data of PH3 alone and the PH3 + CO2 mixture confirmed that CO2 enhances the toxicity of PH3 synergistically in addition to exerting its own toxicity. These results were validated against three independently field-derived strains of strongly resistant C. ferrugineus that confirmed that observed enhancement in toxicity with the PH3 + CO2 mixture was consistent, irrespective of differences in resistance phenotypes and inherent tolerance levels. Results of the current study provide further opportunities to develop new commercially viable strategy to control strongly PH3-resistant C. ferrugineus.

The metachor as a characteristic of the association of electrolytes in aqueous solutions

1984 ◽  
Vol 49 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
Jiří Čeleda ◽  
Stanislav Škramovský
Keyword(s):  
Aqueous Solutions ◽  
Apparent Volume ◽  
Solutions Of Electrolytes ◽  
Molal Volumes ◽  
The Difference ◽  
High Concentrations ◽  
Experimental Values ◽  
Suitable Characteristic ◽  
Association Of Ions ◽  
Very High

Based on the earlier paper introducing a concept of the apparent parachor of a solute in the solution, we have eliminated in the present work algebraically the effect which is introduced into this quantity by the additivity of the apparent molal volumes. The difference remaining from the apparent parachor after substracting the contribution corresponding to the apparent volume ( for which the present authors suggest the name metachor) was evaluated from the experimental values of the surface tension of aqueous solutions for a set of 1,1-, 1,2- and 2,1-valent electrolytes. This difference showed to be independent of concentration up to the very high values of the order of units mol dm-3 but it was directly proportional to the number of the free charges (with a proportionality factor 5 ± 1 cm3 mol-1 identical for all studied electrolytes). The metachor can be, for this reason, a suitable characteristic for detection of the association of ions and formation of complexes in the solutions of electrolytes, up to high concentrations where other methods are failing.

scholarly journals Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo
Keyword(s):  
Ammonia Oxidation ◽  
High Load ◽  
Nuclear Fuels ◽  
Monod Model ◽  
Nernst Equation ◽  
Nitrification Process ◽  
Real Wastewater ◽  
High Concentrations ◽  
Wastewater Samples ◽  
Very High

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

scholarly journals Halogenated Volatile Organic Compounds in Water Samples and Inorganic Elements Levels in Ores for Characterizing a High Anthropogenic Polluted Area in the Northern Latium Region (Italy)

2021 ◽  
Vol 18 (4) ◽  
pp. 1628
Author(s):  
Mario Vincenzo Russo ◽  
Ivan Notardonato ◽  
Alberto Rosada ◽  
Giuseppe Ianiri ◽  
Pasquale Avino
Keyword(s):  
Organic Compounds ◽  
Mean Value ◽  
Greenhouse Crops ◽  
River Waters ◽  
Liquid Liquid Extraction ◽  
Volatile Organic ◽  
High Concentrations ◽  
Very High ◽  
Inorganic Fraction

This paper shows a characterization of the organic and inorganic fraction of river waters (Tiber and Marta) and ores/soil samples collected in the Northern Latium region of Italy for evaluating the anthropogenic/natural source contribution to the environmental pollution of this area. For organic compounds, organochloride volatile compounds in Tiber and Marta rivers were analyzed by two different clean-up methods (i.e., liquid–liquid extraction and static headspace) followed by gas chromatography–electron capture detector (GC-ECD) analysis. The results show very high concentrations of bromoform (up to 1.82 and 3.2 µg L−1 in Tiber and Marta rivers, respectively), due to the presence of greenhouse crops, and of chloroform and tetrachloroethene, due to the presence of handicrafts installations. For the qualitative and quantitative assessment of the inorganic fraction, it is highlighted the use of a nuclear analytical method, instrumental neutron activation analysis, which allows having more information as possible from the sample without performing any chemical-physical pretreatment. The results have evidenced high levels of mercury (mean value 88.6 µg g−1), antimony (77.7 µg g−1), strontium (12,039 µg g−1) and zinc (103 µg g−1), whereas rare earth elements show levels similar to the literature data. Particular consideration is drawn for arsenic (414 µg g−1): the levels found in this paper (ranging between 1 and 5100 µg g−1) explain the high content of such element (as arsenates) in the aquifer, a big issue in this area.

scholarly journals Selective capture of carbon dioxide from hydrocarbons using a metal-organic framework

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Omid T. Qazvini ◽  
Ravichandar Babarao ◽  
Shane G. Telfer
Keyword(s):  
Carbon Dioxide ◽  
Density Functional ◽  
Metal Organic Framework ◽  
Density Functional Theory Calculations ◽  
Time Lags ◽  
X Ray Crystallography ◽  
Metal Organic ◽  
Adsorption Of Co ◽  
Short Time ◽  
Organic Framework

AbstractEfficient and sustainable methods for carbon dioxide capture are highly sought after. Mature technologies involve chemical reactions that absorb CO2, but they have many drawbacks. Energy-efficient alternatives may be realised by porous physisorbents with void spaces that are complementary in size and electrostatic potential to molecular CO2. Here, we present a robust, recyclable and inexpensive adsorbent termed MUF-16. This metal-organic framework captures CO2 with a high affinity in its one-dimensional channels, as determined by adsorption isotherms, X-ray crystallography and density-functional theory calculations. Its low affinity for other competing gases delivers high selectivity for the adsorption of CO2 over methane, acetylene, ethylene, ethane, propylene and propane. For equimolar mixtures of CO2/CH4 and CO2/C2H2, the selectivity is 6690 and 510, respectively. Breakthrough gas separations under dynamic conditions benefit from short time lags in the elution of the weakly-adsorbed component to deliver high-purity hydrocarbon products, including pure methane and acetylene.

scholarly journals Comparative Evaluation of Orthostatic Hypotension in Patients with Diabetic Nephropathy

2021 ◽  
pp. 1-7
Author(s):  
Gamze Aytaş ◽  
Rümeyza Kazancıoğlu ◽  
Ömer C. Elçioğlu ◽  
Meltem Gürsu ◽  
A. Serra Artan ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Orthostatic Hypotension ◽  
Electronic Device ◽  
Channel Blockers ◽  
Factors Affecting ◽  
Clinical Criteria ◽  
Measure Blood Pressure ◽  
Significant Difference ◽  
Male Patients ◽  
Very High

<b><i>Introduction:</i></b> Orthostatic hypotension (OH) affects 5–20% of the population. Our study investigates the presence of OH in diabetic nephropathy (DNP) patients and the factors affecting OH in comparison with nondiabetic chronic kidney disease (NDCKD) patients. <b><i>Method:</i></b> Patients presented to the nephrology clinic, and those who consented were included in the study. DNP was defined by kidney biopsy and/or clinical criteria. NDCKD patients of the same sex, age, and eGFR were matched to DNP patients. Demographic parameters and medications were obtained from the records. OH was determined by Mayo clinic criteria. The same researcher used an electronic device to measure blood pressure (BP). All samples were taken and analyzed the same day for biochemical and hematologic parameters and albuminuria. <b><i>Results:</i></b> 112 (51 F, 61 M, mean age: 62.56 ± 9.35 years) DNP and 94 (40 F, 54 M, mean age: 62.23 ± 10.08 years) NDCKD patients were included. There was no significant difference between DNP and NDCKD groups in terms of OH prevalence (70.5 vs. 61.7%, <i>p</i> = 0.181). Male patients had significantly higher OH prevalence than female patients (74.7 vs. 60.0%, <i>p</i> = 0.026). There was no significant difference in change in systolic BP between the groups (24.00 [10.00–32.00] mm Hg vs. 24.00 [13.75–30.25] mm Hg, <i>p</i> = 0.797), but the change in diastolic BP was significantly higher in the DNP group (8.00 [2.00–13.00] mm Hg vs. 6.00 [2.00–9.00] mm Hg, <i>p</i> = 0.025). In the DNP group, patients with OH had significantly higher uric acid levels than those without OH (7.18 ± 1.55 vs. 6.36 ± 1.65 mg/dL, <i>p</i> = 0.017). And, 73.7% of patients on calcium channel blockers developed OH (<i>p</i> = 0.015), and OH developed in 80.6% of 36 patients on alpha-blockers (<i>p</i> = 0.049). <b><i>Conclusion:</i></b> OH prevalence is very high in CKD, and etiology of CKD does not have a statistically significant effect on the frequency of OH, despite a difference that could be meaningful clinically. Therefore, patients with CKD are checked for OH, with or without concurrent diabetes mellitus. Evaluation of postural BP changes should be a part of nephrology practice.

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