Статті в журналах: "Oxygen supply and demand"

1

IRITA, KAZUO. "Brain oxygen demand and supply balance." JOURNAL OF JAPAN SOCIETY FOR CLINICAL ANESTHESIA 19, no. 1 (1999): 16–24. http://dx.doi.org/10.2199/jjsca.19.16.

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2

Vincent, J. L. "The relationship between oxygen demand, oxygen uptake, and oxygen supply." Intensive Care Medicine 16, S2 (February 1990): S145—S148. http://dx.doi.org/10.1007/bf01785244.

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3

Roytblat, Leonid, Simon Gelman, Edwin L. Bradley, Todd Henderson, and Dale Parks. "Dopamine and hepatic oxygen supply – demand relationship." Canadian Journal of Physiology and Pharmacology 68, no. 8 (August 1, 1990): 1165–69. http://dx.doi.org/10.1139/y90-174.

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The present study examined the effect of small, vasodilating doses of dopamine on the hepatic oxygen supply – uptake ratio. Thirteen miniature pigs weighing 18–27 kg were studied under sodium pentobarbital anesthesia. Hepatic arterial and portal blood flows were measured. Oxygen content in arterial, portal, and hepatic venous blood was determined. Dopamine was infused in doses of 5, 10, and 15 μg∙kg−1∙min−1. Dopamine infusion was associated with a dose-related increase in hepatic oxygen uptake and a dose-independent increase in hepatic oxygen delivery with a maximal increase (30%) in the hepatic oxygen delivery at 10 μg∙kg−1∙min−1. The hepatic oxygen delivery–uptake ratio remained unchanged during dopamine infusion in doses of 5 and 10 μg∙kg−1∙min−1 and significantly decreased during the dose of 15 μg∙kg−1∙min−1. The study demonstrated that an increase in cardiac output and hepatic oxygen delivery during dopamine administration was not associated with an improvement in hepatic oxygen supply – demand relationship since hepatic oxygen uptake also increased.Key words: dopamine, hepatic blood flow, hepatic oxygenation.

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4

Nemoto, Edwin M., Howard Yonas, and Amin Kassam. "Cerebral oximetry: Cerebral Oxygen Supply and Demand." Journal of Neurosurgical Anesthesiology 10, no. 4 (October 1998): 266. http://dx.doi.org/10.1097/00008506-199810000-00046.

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5

Ferro, Giuseppe, Letìzia Spinelli, Carlo Duilio, Marco Spadafora, Franco Guarnaccia, Giorgio Cinquegrana, and Mario Condorelli. "Noninvasive Assessment of Myocardial Oxygen Supply/Demand." American Journal of Noninvasive Cardiology 5, no. 2 (1991): 110–14. http://dx.doi.org/10.1159/000470424.

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6

White, Kathleen M. "Using Continuous SVO2 to Assess Oxygen Supply/Demand Balance in the Critically Ill Patient." AACN Advanced Critical Care 4, no. 1 (February 1, 1993): 134–47. http://dx.doi.org/10.4037/15597768-1993-1011.

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To ensure that tissues arc well oxygenated, oxygen supply and demand are now targets of therapy for the critically ill patient. This chapter reviews the physiologic determinants of oxygen supply, how it is threatened by respiratory or cardiac dysfunction or by hemorrhaged or anemic states, and how it can be assessed in individual patients. Activities and conditions that increase tissue oxygen demand arc examined so that clinicians can identify those patients whose oxygen demands may be excessive and should be controlled. Failure of tissues to consume enough oxygen is explained in patients with critically low delivery or with the maldistributed blood flow state seen in sepsis. The monitoring of mixed venous oxygen saturation is examined as a method of tracking the threats to supply/demand balance and of guiding treatment that can support the adequate oxygenation of tissue

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7

Gelman, S., L. Roytblat, E. L. Bradley, T. Henderson, and D. Parks. "HEPATIC OXYGEN SUPPLY-DEMAND RELATIONSHIP DURING DOPAMINE ADMINISTRATION." Anesthesiology 71, Supplement (September 1989): A160. http://dx.doi.org/10.1097/00000542-198909001-00160.

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8

KIM, Y. D., D. NEMATZADEH, D. E. LEES, P. H. WOLF, J. C. ROSE, P. A. KNOT, and T. E. MACNAMARA. "Halothane Effects on Subendocardial Oxygen Supply-Demand Balance." Survey of Anesthesiology 30, no. 4 (August 1986): 180???181. http://dx.doi.org/10.1097/00132586-198608000-00002.

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9

Tánczos, Krisztián, and Zsolt Molnár. "The oxygen supply–demand balance: A monitoring challenge." Best Practice & Research Clinical Anaesthesiology 27, no. 2 (June 2013): 201–7. http://dx.doi.org/10.1016/j.bpa.2013.06.001.

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10

Kim, Young D., David Nematzadeh, David E. Lees, Pamela H. Wolf, John C. Rose, Peter A. Kot, and Thomas E. Macnamara. "Halothane Effects on Subendocardial Oxygen Supply-Demand Balance." Anesthesia & Analgesia 64, no. 12 (December 1985): 1149???1155. http://dx.doi.org/10.1213/00000539-198512000-00003.

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11

Detterich, Jon A., Roberta Kato, Adam Bush, Patjanaporn Chalacheva, Derek Ponce, Madushka De Zoysa, Payal Shah, et al. "Sickle cell microvascular paradox—oxygen supply‐demand mismatch." American Journal of Hematology 94, no. 6 (April 19, 2019): 678–88. http://dx.doi.org/10.1002/ajh.25476.

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12

Masamoto, Kazuto, Jeff Kershaw, Masakatsu Ureshi, Naosada Takizawa, Hirosuke Kobayashi, Kazuo Tanishita, and Iwao Kanno. "Apparent diffusion time of oxygen from blood to tissue in rat cerebral cortex: implication for tissue oxygen dynamics during brain functions." Journal of Applied Physiology 103, no. 4 (October 2007): 1352–58. http://dx.doi.org/10.1152/japplphysiol.01433.2006.

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To investigate the dynamics of tissue oxygen demand and supply during brain functions, we simultaneously recorded Po2 and local cerebral blood flow (LCBF) with an oxygen microelectrode and laser Doppler flowmetry, respectively, in rat somatosensory cortex. Electrical hindlimb stimuli were applied for 1, 2, and 5 s to vary the duration of evoked cerebral metabolic rate of oxygen (CMRO2). The electrical stimulation induced a robust increase in Po2 (4–9 Torr at peak) after an increase in LCBF (14–26% at peak). A consistent lag of ∼1.2 s (0.6–2.3 s for individual animals) in the Po2 relative to LCBF was found, irrespective of stimulus length. It is argued that the lag in Po2 was predominantly caused by the time required for oxygen to diffuse through tissue. During brain functions, the supply of fresh oxygen further lagged because of the latency of LCBF onset (∼0.4 s). The results indicate that the tissue oxygen supports excess demand until the arrival of fresh oxygen. However, a large drop in Po2 was not observed, indicating that the evoked neural activity demands little extra oxygen or that the time course of excess demand is as slow as the increase in supply. Thus the dynamics of Po2 during brain functions predominantly depend on the time course of LCBF. Possible factors influencing the lag between demand and supply are discussed, including vascular spacing, reactivity of the vessels, and diffusivity of oxygen.

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13

Gelman, S., E. Dillard, and D. A. Parks. "Glucagon increases hepatic oxygen supply-demand ratio in pigs." American Journal of Physiology-Gastrointestinal and Liver Physiology 252, no. 5 (May 1, 1987): G648—G653. http://dx.doi.org/10.1152/ajpgi.1987.252.5.g648.

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The present study was performed on eight young pigs to test the hypothesis that glucagon increases hepatic oxygen supply to a greater extent than hepatic oxygen uptake, providing a better hepatic oxygen supply-demand relationship. The experiments were performed under pentobarbital sodium anesthesia and controlled ventilation. Splanchnic blood flow was studied using radioactive microspheres. Glucagon was administered in doses of 1 and 5 micrograms X kg-1 X min-1. During glucagon infusion, hepatic arterial blood flow substantially increased, splenic and pancreatic blood flows increased moderately, while stomach and intestinal blood flows, as well as portal blood flow did not change significantly. Shunting of both 9- and 15-micron spheres through preportal tissues did not change significantly. Oxygen content in arterial or portal venous blood did not change significantly, while it increased in hepatic venous blood by 30%. There were no differences in the effects between the doses of glucagon administered. There was no correlation found between changes in hepatic oxygen supply and cardiac output or blood pressure. The changes observed during glucagon administration resulted in an increase in oxygen delivery to the liver and hepatic oxygen supply-uptake ratio.

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14

Hart, Bradley J., Xiaoming Bian, Patricia A. Gwirtz, Srinath Setty, and H. Fred Downey. "Right ventricular oxygen supply/demand balance in exercising dogs." American Journal of Physiology-Heart and Circulatory Physiology 281, no. 2 (August 1, 2001): H823—H830. http://dx.doi.org/10.1152/ajpheart.2001.281.2.h823.

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This is the first investigation of right ventricular (RV) myocardial oxygen supply/demand balance in a conscious animal. A novel technique developed in our laboratory was used to collect right coronary (RC) venous blood samples from seven instrumented, conscious dogs at rest and during graded treadmill exercise. Contributions of the RV oxygen extraction reserve and the RC flow reserve to exercise-induced increases in RV oxygen demand were measured. Strenuous exercise caused a 269% increase in RV oxygen consumption. Expanded arteriovenous oxygen content difference (A-VΔO2) provided 58% of this increase in oxygen demand, and increased RC blood flow (RCBF) provided 42%. At less strenuous exercise, expanded A-VΔO2 provided 60–80% of the required oxygen, and increases in RCBF were small and driven by increased aortic pressure. RC resistance fell only at strenuous exercise after the extraction reserve had been mobilized. Thus RC resistance was unaffected by large decreases in RC venous Po 2 until an apparent threshold at 20 mmHg was reached. Comparisons of RV findings with published left ventricular data from exercising dogs demonstrated that increased O2 demand of the left ventricle is met primarily by increasing coronary flow, whereas increased O2extraction makes a greater contribution to RV O2 supply.

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15

Kure, Shruti, Sneha Panicker, Siddhi Panchal, and Prof Prakash Khelage. "Oxygen Supply Management System." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (May 31, 2022): 1359–67. http://dx.doi.org/10.22214/ijraset.2022.42519.

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Abstract: The COVID’19 pandemic, recent spike of Omicron variant and the upsurge in air pollution in metropolitan cities like Delhi has highlighted the importance of oxygen cylinders andother equipment’s. The various units in the health system such as: General wards, Emergency transport, Delivery rooms, Operatingtheaters, Intensive care units (ICU) also require a regular supply of oxygen. Thus, timely and powerful planning for reliable oxygensupply and delivery is needed to protect and save lives of people who are in need. Due to the unavailability of a proper channel of acquiring Oxygen during the pandemic, forced people to search for the supply of oxygen through phone calls and various social media platforms. But only few people got reliable suppliers and many could not get their demand satisfied at the right time. Evenhospitals faced the same situation. To combat such problems,in this project we propose a unique system for Oxygen Supply Management to people and hospitals which can meet the crisisin an effective way. In order to overcome the shortage of oxygen in the coming times, this proposed system will be launched as a digital platform to fast-pace the supply chain to both people and hospitals. Index Terms: Covid-19, pandemic, Omicron

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16

Madden, Kenneth M., Gale Tedder, and Chris Lockhart. "The oral glucose tolerance test induces myocardial ischemia in healthy older adults." Clinical & Investigative Medicine 30, no. 3 (June 1, 2007): 118. http://dx.doi.org/10.25011/cim.v30i3.1080.

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Purpose: Postprandial myocardial ischemia has been observed in frail older adults with postprandial hypotension and in patients with severe coronary artery disease, especially after high doses of carbohydrates. The impact of oral glucose on myocardial oxygen supply and demand in healthy older adults without postprandial hypotension or postprandial angina remains unexamined. We hypothesized that oral glucose would result in decreased myocardial oxygen supply relative to demand in a healthy older subject pool free of postprandial hypotension, reversible coronary risk factors and postprandial angina. Methods: 19 older adults (mean age 71.9±1.1 yr) were screened for reversible coronary risk factors. Subjects were given a standardized oral glucose load (75 g) or a sham isovolumetric unsweetened drink during two separate sessions. Indirect measures of oxygen supply (Diastolic Pressure Time Index, DPTI) and demand (Rate Pressure Product, RPP; Systolic Pressure Time Index, SPTI) were obtained from aortic arterial blood pressure waveforms. The Subendocardial Viability Ratio (SEVR, DPTI/SPTI) and DPTI/RPP were also calculated. Results: Oral glucose resulted in decreases in both SEVR (P=0.016) and DPTI/RPP (P=0.028) in the glucose session, indicating a decrease in the relative myocardial oxygen supply to demand. This was due solely to a decrease in myocardial oxygen supply while measures of myocardial oxygen demand did not change significantly. Conclusions: Oral glucose decreases myocardial oxygen supply in older adults free of severe coronary artery disease and without postprandial hypotension. This represents a previously unrecognized complication of oral glucose tolerance tests in healthy older adults.

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17

Nagano, K., S. Gelman, E. L. Bradley, and D. Parks. "Hypothermia, hepatic oxygen supply-demand, and ischemia-reperfusion injury in pigs." American Journal of Physiology-Gastrointestinal and Liver Physiology 258, no. 6 (June 1, 1990): G910—G918. http://dx.doi.org/10.1152/ajpgi.1990.258.6.g910.

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We examined the effects of two degrees of hypothermia on hepatic oxygen delivery and uptake, hepatic lactate uptake as a marker of hepatic function, and the effect of hypothermia on ischemia-reperfusion injury in the liver in miniature pigs (n = 18, 21-30 kg body wt). Hepatic arterial and portal venous blood flows were measured while hepatic oxygen delivery was progressively decreased without venous congestion in the preportal area. With decreases in hepatic blood and oxygen supply, oxygen extraction gradually increased from 50 to 90% in the normothermic group and from 25 to 70 and 84% in the hypothermic (30. and 34 degrees C, respectively) groups. The values of critical hepatic oxygen delivery were between 7.3 and 11.9 ml O2.min-1.100 g-1 without significant differences among the groups. During reperfusion after ischemic insult, hepatic oxygen uptake returned to base-line values in both hypothermic groups but remained substantially below base-line values in normothermic groups of animals. Hepatic enzyme concentrations (lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, and alcohol dehydrogenase) were substantially increased (up to 30-fold) in normothermic animals, but the concentrations did not increase in either of the hypothermic groups. These results demonstrated that hypothermia per se does not affect hepatic oxygen delivery but decreases hepatic oxygen demand and uptake, provides an effective protection from hepatic oxygen deprivation, and lessens reperfusion injury.

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18

Bos, Willem Jan W., Robert Zietse, Karel H. Wesseling, and Nico Westerhof. "Effects of arteriovenous fistulas on cardiac oxygen supply and demand." Kidney International 55, no. 5 (May 1999): 2049–53. http://dx.doi.org/10.1046/j.1523-1755.1999.00433.x.

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19

Nagano, K., S. Gelman, D. Parks, T. Henderson, and T. Lowery. "HEPATIC OXYGEN SUPPLY-DEMAND RELATIONSHIP DURING ANESTHESIA IN THE PIG." Anesthesiology 69, no. 3A (September 1, 1988): A440. http://dx.doi.org/10.1097/00000542-198809010-00439.

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20

Zong, Pu, Johnathan D. Tune, and H. Fred Downey. "Mechanisms of Oxygen Demand/Supply Balance in the Right Ventricle." Experimental Biology and Medicine 230, no. 8 (September 2005): 507–19. http://dx.doi.org/10.1177/153537020523000801.

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Few studies have investigated factors responsible for the O2 demand/supply balance in the right ventricle. Resting right coronary blood flow is lower than left coronary blood flow, which Is consistent with the lesser work of the right ventricle. Because right and left coronary artery perfusion pressures are Identical, right coronary conductance is less than left coronary conductance, but the signal relating this conductance to the lower right ventricular O2 demand has not been defined. At rest, the left ventricle extracts ~75% of the O2 delivered by coronary blood flow, whereas right ventricular O2 extraction Is only ~50%. As a result, resting right coronary venous PO2 is ~30 mm Hg, whereas left coronary venous PO2 is ~20 mm Hg. Right coronary conductance does not sufficiently restrict flow to force the right ventricle to extract the same percentage of O2 as the left ventricle. Endogenous nitric oxide impacts the right ventricular O2 demand/supply balance by increasing the right coronary blood flow at rest and during acute pulmonary hypertension, systemic hypoxia, norepinephrine infusion, and coronary hypoperfusion. The substantial right ventricular O2 extraction reserve is used preferentially during exercise-induced increases in right ventricular myocardial O2 consumption. An augmented, sympathetic-mediated vasoconstrictor tone blunts metabolically mediated dilator mechanisms during exercise and forces the right ventricle to mobilize its O2 extraction reserve, but this tone does not limit resting right coronary flow. During exercise, right coronary vasodilation does not occur until right coronary venous PO2 decreases to ~20 mm Hg. The mechanism responsible for right coronary vasodilation at low PO2 has not been delineated. In the poorly autoregulating right coronary circulation, reduced coronary pressure unloads the coronary hydraulic skeleton and reduces right ventricular systolic stiffness. Thus, normal right ventricular external work and O2 demand/supply balance can be maintained during moderate coronary hypoperfusion.

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21

Crystal, George J., Song-Jung Kim, M. Ramez Salem, and Mohamed Abdel-Latif. "Myocardial Oxygen Supply/Demand Relations During Phenylephrine Infusions in Dogs." Anesthesia & Analgesia 73, no. 3 (September 1991): 283???288. http://dx.doi.org/10.1213/00000539-199109000-00010.

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22

Gelman, S., L. Roytblat, E. L. Bradley, T. Henderson, and D. Parks. "HEPATIC OXYGEN SUPPLY-DEMAND DURING H1 AND H2 RECEPTOR BLOCKADE." Anesthesiology 71, Supplement (September 1989): A243. http://dx.doi.org/10.1097/00000542-198909001-00243.

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23

Vespa, Paul M. "Brain tissue oxygen monitoring: A measure of supply and demand*." Critical Care Medicine 34, no. 6 (June 2006): 1850–52. http://dx.doi.org/10.1097/01.ccm.0000219370.99823.5b.

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24

Yamasaki, Shiori. "Oxygen demand and supply in Zizania latifolia and Phragmites australis." Aquatic Botany 29, no. 3 (December 1987): 205–15. http://dx.doi.org/10.1016/0304-3770(87)90016-7.

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25

Thoman, W. J., S. Lampotang, D. Gravenstein, and J. van der Aa. "AUTOREGULATION MEDIATED BY OXYGEN DEMAND/SUPPLY IN A BRAIN MODEL." Anesthesiology 89, Supplement (September 1998): 540A. http://dx.doi.org/10.1097/00000542-199809100-00007.

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26

Gelman, S., and E. Dillard. "HEPATIC OXYGEN SUPPLY-DEMAND RELATIONSHIP DURING ANESTHESIA IN THE DOG." Anesthesiology 63, Supplement (September 1985): A540. http://dx.doi.org/10.1097/00000542-198509001-00540.

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27

Yuzawa, Izumi, Sava Sakadžić, Vivek J. Srinivasan, Hwa Kyoung Shin, Katharina Eikermann-Haerter, David A. Boas, and Cenk Ayata. "Cortical Spreading Depression Impairs Oxygen Delivery and Metabolism in Mice." Journal of Cerebral Blood Flow & Metabolism 32, no. 2 (October 19, 2011): 376–86. http://dx.doi.org/10.1038/jcbfm.2011.148.

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Cortical spreading depression (CSD) is associated with severe hypoperfusion in mice. Using minimally invasive multimodal optical imaging, we show that severe flow reductions during and after spreading depression are associated with a steep decline in cerebral metabolic rate of oxygen. Concurrent severe hemoglobin desaturation suggests that the oxygen metabolism becomes at least in part supply limited, and the decrease in cortical blood volume implicates vasoconstriction as the mechanism. In support of oxygen supply-demand mismatch, cortical nicotinamide adenine dinucleotide (NADH) fluorescence increases during spreading depression for at least 5 minutes, particularly away from parenchymal arterioles. However, modeling of tissue oxygen delivery shows that cerebral metabolic rate of oxygen drops more than predicted by a purely supply-limited model, raising the possibility of a concurrent reduction in oxygen demand during spreading depression. Importantly, a subsequent spreading depression triggered within 15 minutes evokes a monophasic flow increase superimposed on the oligemic baseline, which markedly differs from the response to the preceding spreading depression triggered in naive cortex. Altogether, these data suggest that CSD is associated with long-lasting oxygen supply-demand mismatch linked to severe vasoconstriction in mice.

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28

Zhao, Ying Jie, and Hui Xiang Wu. "Design and Analysis of the Oxygen Regulator in the Aircraft." Applied Mechanics and Materials 752-753 (April 2015): 1073–77. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.1073.

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Based on the analysis of the aircrafts oxygen supply performance, an new electronic oxygen supply regulator is designed. Meanwhile, the design calculation work is conducted and the structure parameters is obtained. From the results we can see that the designed oxygen regulator can satisfy the pilot’s oxygen demand under designed heights and that oxygen flow rise under different outlet pressures is not boundless as the valve opening width is increasing .Furthermore, when the valve opens to the half of its radius, the oxygen flow no longer changes as the opening width is increasing. Also, when it opens to the maximum, the peak demand under emergency can be satisfied.

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29

Haselgrove, J. C., I. M. Shapiro, and S. F. Silverton. "Computer modeling of the oxygen supply and demand of cells of the avian growth cartilage." American Journal of Physiology-Cell Physiology 265, no. 2 (August 1, 1993): C497—C506. http://dx.doi.org/10.1152/ajpcell.1993.265.2.c497.

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We have used computer modeling studies to investigate the oxygen supply to the prehypertrophic and hypertrophic regions of avian growth plate. We measured experimentally the characteristics of the oxygen consumption of chondrocytes at different oxygen tensions. The oxygen consumption decreases at low oxygen tensions. This relation between oxygen tension and oxygen consumption serves as a protective mechanism that prevents the cells in the prehypertrophic zone from becoming anoxic in the regions farthest from the blood vessels. The results of the calculations, when combined with redox measurements of the cells in the growth plate, indicate that the metabolism of the chondrocytes is not controlled simply by the available oxygen supply.

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30

Stahl, L. D., H. R. Weiss, and L. C. Becker. "Myocardial oxygen consumption, oxygen supply/demand heterogeneity, and microvascular patency in regionally stunned myocardium." Circulation 77, no. 4 (April 1988): 865–72. http://dx.doi.org/10.1161/01.cir.77.4.865.

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31

Islam, Eftahrul, and Dr Ganesh D. "Survey Paper on Mankind Essential – Oxygen." International Journal for Research in Applied Science and Engineering Technology 10, no. 3 (March 31, 2022): 1068–70. http://dx.doi.org/10.22214/ijraset.2022.40803.

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Abstract: The Second wave of COVID’19 Coronavirus has brought a human unexpected condition for demand on Oxygen Supply in all over the world and especially in India. Due to lack of proper channel of getting Oxygen, made people to find the supply of oxygen through social media like phone calls, SMS, WhatsApp message, posting through Facebook, twitter and so many. But only limited people got the right suppliers and many could not get their demand satisfied at the right time. Even hospitals had difficulties during this situation. To face such problems, in this project we propose a unique system for Online Oxygen Management System which can effectively meet the crisis situation in an effective way. To fight the crisis of oxygen shortage in the face of the raging Covid-19 wave, this proposed system is launched as a digital platform to fast-pace the supply chain to both people and hospitals.

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32

YABE, Hiroki, and Yusuke NISHIDA. "Effects of Different Pedal Rates on Oxygen Supply and Metabolic Demand." Rigakuryoho Kagaku 24, no. 4 (2009): 617–24. http://dx.doi.org/10.1589/rika.24.617.

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33

Matsumoto, Tamaki, Minoru Shinohara, Masashi Shibata, and Toshio Moritani. "The noninvasive method for evaluation of myocardial oxygen supply and demand." Taiikugaku kenkyu (Japan Journal of Physical Education, Health and Sport Sciences) 38, no. 4 (1993): 257–64. http://dx.doi.org/10.5432/jjpehss.kj00003391955.

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34

Prociuk, JL. "Management of cerebral oxygen supply-demand balance in blunt head injury." Critical Care Nurse 15, no. 4 (August 1, 1995): 38–45. http://dx.doi.org/10.4037/ccn1995.15.4.38.

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35

Braunwald, Eugene, and David S. Warner. "Reducing Myocardial Injury by Minimizing Imbalance between Oxygen Supply and Demand." Anesthesiology 107, no. 1 (July 1, 2007): 161–63. http://dx.doi.org/10.1097/01.anes.0000268391.73266.5b.

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Abstract Factors Influencing Infarct Size following Experimental Coronary Artery Occlusion. By P. R. Maroko, J. K. Kjekshus, B. E. Sobel, T. Watanabe, J. W. Covell, J. Ross, Jr., and E. Braunwald. Circulation 1971; 43:67–82. Reprinted with permission. The purpose of this study was to determine whether hemodynamic and pharmacologic factors can influence the extent and severity of myocardial necrosis produced by coronary occlusion. In 48 dogs, 10 to 14 epicardial leads were recorded on the anterior surface of the left ventricle in the distribution and vicinity of the site of occlusion of a branch of the left anterior descending coronary artery. The average S-T segment elevation for each animal was determined at 5-min intervals after occlusion. This elevation was used as an index of the presence and severity of myocardial ischemic injury. Isoproterenol, ouabain, glucagon, bretylium, and tachycardia given prior to a repeated occlusion each increased the severity and extent of ischemic injury, while propranolol decreased it. Elevation of arterial pressure with methoxamine reduced the occlusion-induced S-T segment elevation, and lowering of the mean arterial pressure by hemorrhage had the opposite effect. In 19 additional experiments, propranolol, isoproterenol, and alterations in arterial pressure produced similar alterations in S-T segment elevation when these interventions were applied as long as 3 hr after ligation. Myocardial creatine phosphokinase (CPK) activity determined 24 hr after coronary artery ligation correlated well with S-T segment elevation at the same sites recorded 15 min after ligation. Moreover, isoproterenol increased and propranolol decreased the area of depression of myocardial CPK activity. We conclude that the hemodynamic status and neurohumoral background at the time of coronary occlusion and for at least 3 hr thereafter can alter the extent and severity of myocardial ischemic injury and myocardial necrosis.

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36

Bavis, R. W., F. L. Powell, A. Bradford, C. C. W. Hsia, J. E. Peltonen, J. Soliz, B. Zeis, et al. "Respiratory plasticity in response to changes in oxygen supply and demand." Integrative and Comparative Biology 47, no. 4 (October 1, 2007): 532–51. http://dx.doi.org/10.1093/icb/icm070.

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37

Reinhart, Konrad, Tobias Rudolph, Donald L. Bredle, Lutz Hannemann, and Stephen M. Cain. "Comparison of Central-Venous to Mixed-Venous Oxygen Saturation During Changes in Oxygen Supply/Demand." Chest 95, no. 6 (June 1989): 1216–21. http://dx.doi.org/10.1378/chest.95.6.1216.

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38

Giomi, Folco, Alberto Barausse, Carlos M. Duarte, Jenny Booth, Susana Agusti, Vincent Saderne, Andrea Anton, Daniele Daffonchio, and Marco Fusi. "Oxygen supersaturation protects coastal marine fauna from ocean warming." Science Advances 5, no. 9 (September 2019): eaax1814. http://dx.doi.org/10.1126/sciadv.aax1814.

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Ocean warming affects the life history and fitness of marine organisms by, among others, increasing animal metabolism and reducing oxygen availability. In coastal habitats, animals live in close association with photosynthetic organisms whose oxygen supply supports metabolic demands and may compensate for acute warming. Using a unique high-frequency monitoring dataset, we show that oxygen supersaturation resulting from photosynthesis closely parallels sea temperature rise during diel cycles in Red Sea coastal habitats. We experimentally demonstrate that oxygen supersaturation extends the survival to more extreme temperatures of six species from four phyla. We clarify the mechanistic basis of the extended thermal tolerance by showing that hyperoxia fulfills the increased metabolic demand at high temperatures. By modeling 1 year of water temperatures and oxygen concentrations, we predict that oxygen supersaturation from photosynthetic activity invariably fuels peak animal metabolic demand, representing an underestimated factor of resistance and resilience to ocean warming in ectotherms.

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Golub, Aleksander S., Sami C. Dodhy, and Roland N. Pittman. "Oxygen dependence of respiration in rat spinotrapezius muscle contracting at 0.5–8 twitches per second." Journal of Applied Physiology 125, no. 1 (July 1, 2018): 124–33. http://dx.doi.org/10.1152/japplphysiol.01136.2016.

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The oxygen dependence of respiration was obtained in situ in microscopic regions of rat spinotrapezius muscle for different levels of metabolic activity produced by electrical stimulation at rates from 0.5 to 8 Hz. The rate of O2 consumption (V̇o2) was measured with phosphorescence quenching microscopy (PQM) as the rate of O2 disappearance in a muscle with rapid flow arrest. The phosphorescent oxygen probe was loaded into the interstitial space of the muscle to give O2 tension (Po2) in the interstitium. A set of sigmoid curves relating the Po2 dependence of V̇o2 was obtained with a Po2-dependent region below a characteristic Po2 (~30 mmHg) and a Po2-independent region above this Po2. The V̇o2(Po2) plots were fit by the Hill equation containing O2 demand (rest to 8 Hz: 216 ± 26 to 636 ± 77 nl O2/cm3 s) and the Po2 value corresponding to O2 demand/2 (rest to 8 Hz: 22 ± 4 to 11 ± 1 mmHg). The initial Po2 and V̇o2 pairs of values measured at the moment of flow arrest formed a straight line, determining the rate of oxygen supply. This line had a negative slope, equal to the oxygen conductance for the O2 supply chain. For each level of tissue blood flow the set of possible values of Po2 and V̇o2 consists of the intersection points between this O2 supply line and the set of V̇o2 curves. An electrical analogy for the intraorgan O2 supply and consumption is an inverting transistor amplifier, which allows the use of graphic analysis methods for prediction of the behavior of the oxygen processing system in organs. NEW & NOTEWORTHY The sigmoidal shape of curves describing oxygen dependence of muscle respiration varies from basal to maximal workload and characterizes the oxidative metabolism of muscle. The rate of O2 supply depends on extracellular O2 tension and is determined by the overall oxygen conductance in the muscle. The dynamics of oxygen consumption is determined by the supply line that intersects the oxygen demand curves. An electrical analogy for the oxygen supply/consumption system is an inverting transistor amplifier.

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Walley, K. R. "Heterogeneity of oxygen delivery impairs oxygen extraction by peripheral tissues: theory." Journal of Applied Physiology 81, no. 2 (August 1, 1996): 885–94. http://dx.doi.org/10.1152/jappl.1996.81.2.885.

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The hypothesis that the distribution of oxygen demand in relation to oxygen supply (dO2/qO2) effects oxygen extraction in peripheral tissues was tested. By using a simple theoretical model, realistic biphasic oxygen consumption-delivery relationships were predicted from dO2/qO2 distributions. Increasing width (relative dispersion) of the dO2/qO2 distribution, indicating mismatch between oxygen demand and supply, nonlinearly decreased the critical oxygen extraction ratio (calculated by using dual-line regression). Skewed dO2/qO2 distributions had a lesser effect. Incomplete oxygen uptake, due to diffusion limitation or other causes of physiological arteriovenous shunt, linearly decreased the critical oxygen extraction ratio. Approximate dO2/qO2 distributions were then estimated from previously reported capillary transit-time distributions. Critical oxygen extraction ratios predicted from these estimated dO2/qO2 distributions match reported values. This theoretical approach also predicts the decrease in the critical oxygen extraction ratio in porcine gut after endotoxin infusion in the companion paper (M. F. Humer, P. T. Phang, B. P. Friesen, M. F. Allard, C. M. Goddard, and K. R. Walley. J. Appl. Physiol. 81: 895–904, 1996). Much as pulmonary ventilation-perfusion relationships account for pulmonary gas exchange, dO2/qO2 distributions quantitatively account for measured tissue oxygen extraction and predict novel features of the relationship between heterogeneity and oxygen extraction.

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Driedzic, William R. "Matching of cardiac oxygen delivery and fuel supply to energy demand in teleosts and cephalopods." Canadian Journal of Zoology 66, no. 5 (May 1, 1988): 1078–83. http://dx.doi.org/10.1139/z88-158.

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Both fish and cephalopods have a single systemic ventricle which performs mechanical work at similar levels in the two groups of organisms. This example of convergent evolution is used to identify common features of cardiac oxygen delivery and fuel supply in relation to energy demand. Foremost, both groups of animals exhibit morphological alterations to enhance oxygen delivery to the myocardium. In cephalopods, the heart is positioned to directly receive oxygenated blood, and coronary arteries can be present in both fish and cephalopods. At the cellular level, oxygen extraction is facilitated by elevated concentrations of myoglobin in the hearts of fish, which face particularly acute low levels of extracellular oxygen. These features represent adaptations to meet the challenge of oxygen delivery. In temperate-zone teleosts and cephalopods, maximal in vitro activity of ATPase reflects maximal in situ oxygen demand. In both groups of animals, there is a linear relationship between maximal in vitro hexokinase and ATPase activities, and in temperate-zone teleosts a similar relationship exists between carnitine palmitoyl transferase and ATPase activities. These enzyme activities are interpreted to reflect adaptations in maximal capacities to utilize glucose and fatty acids in response to increased energy demand.

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Tahir, Saad, Asher Ramish, and Talha Mehmood. "“We can’t breathe!” – A dilemma faced by Total Technologies (Pvt.) Ltd. amid oxygen cylinder crisis." Emerald Emerging Markets Case Studies 12, no. 1 (March 21, 2022): 1–22. http://dx.doi.org/10.1108/eemcs-05-2021-0175.

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Learning outcomes This case study aims to be taught at an MBA level. Students who are majoring in the supply chain would benefit the most from this case study. This case study has elements of logistics management, supply chain management, supply chain strategies, warehouse and logistics and responsible supply chain. The learning outcome of this case study could be seen if the students identify the gaps in the real market setting and come up with strategies that would connect and/or fill the areas missing. Teaching objective 1: students should be able to identify unstable demand scenarios and learn how demand collaboration could be implemented in that setting. Teaching objective 2: students should identify how a transparent and interconnected supply chain, both upstream and downstream, can be created. Teaching objective 3: students should be able to understand the role of a responsible supply chain and to define the role and responsibility of each party. Teaching objective 4: students should be able to learn the dynamics of safety stocks, reorder points and incorporate that in warehouse management decisions. Case overview/synopsis Based in Lahore, Pakistan, Total Technologies (Pvt.) Ltd is a company that supplies medical equipment and provides solutions in the health-care industry. This case explores the supply chain issues faced by Tallat Mehmood, who is the Managing Director of the company, during the third wave of the COVID-19 pandemic in April 2021. Oxygen cylinders have become the need of the hour as more and more patients need oxygen. The supply of medical gases across Pakistan has become a logistical issue, causing hospital reserves to be drained without timely replenishment. Increasing the number of beds in hospitals, with limited oxygen outlets, has increased the demand for oxygen cylinders. Operating under unstable demand and not being able to meet it has caused Tallat to realize that the company is out of its comfort zone and is not responding well to the environment. The company needs to redesign the supply chain as well as collaborate with the supplier and buyer to provide better levels of service. Complexity academic level Masters level supply chain courses. Supplementary materials Teaching Notes are available for educators only. Subject code CSS 9: Operations and logistics.

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Weibel, E. R., C. R. Taylor, J. M. Weber, R. Vock, T. J. Roberts, and H. Hoppeler. "Design of the oxygen and substrate pathways. VII. Different structural limits for oxygen and substrate supply to muscle mitochondria." Journal of Experimental Biology 199, no. 8 (August 1, 1996): 1699–709. http://dx.doi.org/10.1242/jeb.199.8.1699.

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This paper integrates the results of a series of studies on the supply of O2 and substrates for oxidative muscle metabolism and draws conclusions on the role of structural design in partitioning and limiting substrate supply. The studies compared dogs and goats exercising at different intensities and combined physiological, biochemical and morphometric investigations. In both species, the rate of fatty acid oxidation reached an upper limit at low exercise intensities, and only glucose consumption was increased at higher exercise intensities. The supply of both glucose and fatty acids from the capillaries reached maximal rates at low exercise intensities; this limitation is related to the design of the sarcolemma as calculations suggest that the endothelium introduces only a small resistance to substrate flux. From these findings, it appears that the capillaries are designed to satisfy O2 supply up to maximal O2 demand. The increase in substrate supply to the mitochondria at higher exercise intensities is achieved by drawing on intracellular stores of glycogen and lipids. The size of these stores is larger in dogs than in goats, providing the athletic species with twice the fuel reserves. These findings are interpreted on the basis of a network model with fluxes partitioned between direct and indirect pathways and with some structures shared by more than one function. Whereas O2 is supplied through a direct pathway, the supply of both substrates is split temporally to allow, during exercise, immediate fuel supply to the mitochondria from intracellular stores; these are replaced from the vasculature, during periods of rest, to a size commensurate with high rates of combustion. Considering this complexity, we conclude that the results are compatible with the principle of symmorphosis applied to a network structure and that the adjustment of design to functional demand involves different structures for O2 and for substrates.

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Wheaton, William W., and Navdeep S. Chandel. "Hypoxia. 2. Hypoxia regulates cellular metabolism." American Journal of Physiology-Cell Physiology 300, no. 3 (March 2011): C385—C393. http://dx.doi.org/10.1152/ajpcell.00485.2010.

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Adaptation to lowering oxygen levels (hypoxia) requires coordinated downregulation of metabolic demand and supply to prevent a mismatch in ATP utilization and production that might culminate in a bioenergetic collapse. Hypoxia diminishes ATP utilization by downregulating protein translation and the activity of the Na-K-ATPase. Hypoxia diminishes ATP production in part by lowering the activity of the electron transport chain through activation of the transcription factor hypoxia-inducible factor-1. The decrease in electron transport limits the overproduction of reactove oxygen species during hypoxia and slows the rate of oxygen depletion to prevent anoxia. In this review, we discuss these mechanisms that diminish metabolic supply and demand for adaptation to hypoxia.

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45

Oshima, Yoshiaki, Naoto Okazaki, Kazumi Funaki, Shunsaku Takahashi, Tomomi Harada, Akihiro Otsuki, and Yoshimi Inagaki. "Prone Position Impairs Oxygen Supply-Demand Balance During Systemic Hypoxia in Rabbits." Yonago Acta Medica 64, no. 2 (2021): 229–33. http://dx.doi.org/10.33160/yam.2021.05.012.

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&NA;. "Venous O2 Saturation Reflects the Balance Between Supply and Demand of Oxygen." Anesthesia & Analgesia 76, no. 6 (June 1993): 1377–78. http://dx.doi.org/10.1213/00000539-199306000-00046.

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47

&NA;. "Venous O2 Saturation Reflects the Balance Between Supply and Demand of Oxygen." Anesthesia & Analgesia 76, no. 6 (June 1993): 1377–78. http://dx.doi.org/10.1213/00000539-199376060-00046.

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O'Reilly, Kirk T., and Augus E. McGrath. "Oxygen Supply and Demand: Considerations for the Design of Groundwater Remediation Systems." Soil and Sediment Contamination: An International Journal 11, no. 3 (May 2002): 382. http://dx.doi.org/10.1080/20025891106952.

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Salvi, L., A. Grillo, P. Salvi, G. Parati, and S. Perlini. "TROPONIN INCREASE AND SUBENDOCARDIAL OXYGEN SUPPLY AND DEMAND IMBALANCE IN CARDIAC AMYLOIDOSIS." Journal of Hypertension 36, Supplement 1 (June 2018): e197. http://dx.doi.org/10.1097/01.hjh.0000539548.31652.18.

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GREGORETTI, SERGIO, SIMON GELMAN, ALAN DIMICK, and JIMMY PROCTOR. "Total Body Oxygen Supply-Demand Balance in Burned Patients Under Enflurane Anesthesia." Journal of Trauma: Injury, Infection, and Critical Care 27, no. 2 (February 1987): 158–60. http://dx.doi.org/10.1097/00005373-198702000-00011.

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