Ml Of Oxygen Research Articles

Systemically injected oxygen within rapidly dissolving microbubbles improves the outcomes of severe hypoxaemia in swine.

Acute respiratory failure can cause profound hypoxaemia that leads to organ injury or death within minutes. When conventional interventions are ineffective, the intravenous administration of oxygen can rescue patients from severe hypoxaemia, but at the risk of microvascular obstruction and of toxicity of the carrier material. Here we describe polymeric microbubbles as carriers of high volumes of oxygen (350-500 ml of oxygen per litre of foam) that are stable in storage yet quickly dissolve following intravenous injection, reverting to their soluble and excretable molecular constituents. In swine with profound hypoxaemia owing to acute and temporary (12 min) upper-airway obstruction, the microbubble-mediated delivery of oxygen led to: the maintenance of critical oxygenation, lowered burdens of cardiac arrest, improved survival, and substantially improved neurologic and kidney function in surviving animals. Our findings underscore the importance of maintaining a critical threshold of oxygenation and the promise of injectable oxygen as a viable therapy in acute and temporary hypoxaemic crises.

Optimizing electrochemical power generation: Harnessing synergies and surface innovation in NiTe-modified MOF nanoarchitectures

Metal-organic frameworks (MOFs) are considered potential electrocatalysts due to their high specific surface area (SSA) and the facilitation of efficient synergistic interactions. In this work, we have implemented a simple and cost-effective surface modification approach to design an efficient electrocatalyst for energy-conversion technologies, specifically water splitting. This work focuses on engineering a novel NiTe functionalized MOF structure wherein NiTe within the MOF channels is the core material, intricately intertwined with highly dispersed Ni particles enveloped by Ni MOF. This fusion of MOFs and NiTe within a designed configuration produces an efficient electrocatalyst with synergistic and surface interface effects and demonstrates bifunctional activity for water splitting. Among the prepared catalysts, one of the resulting catalysts (named Ni MOF/Ni/Ni10Te8) exhibits a low overpotential of 99 mV for the hydrogen evolution reaction (HER) and 180 mV for the oxygen evolution reaction (OER), both benchmarked against RHE @10 mA cm−2. This performance remains steady, with a stability of 99 % after 15 h of continuous operation. Furthermore, the Ni MOF/Ni/Ni10Te8 catalyst also operates in seawater electrocatalysis, requiring a low overpotential of 440 mV at 10 mA cm−2 to produce 70 mL of hydrogen and 34 mL of oxygen. Equally noteworthy are the Faradaic efficiencies achieved, with hydrogen production at 95.7 % and oxygen production at 92.9 %. Developing efficient and economically viable electrocatalysts like the Ni MOF/Ni/NiTe catalyst will advance a cleaner and more sustainable future.

320 Oxygenated Peritoneal Perfluorodecalin Improves Response to Normobaric Hypoxic Exposure in Swine

OBJECTIVES/GOALS: Patients suffering from respiratory failure have few options to support oxygenation and carbon dioxide removal aside from mechanical ventilation. Our objective was to test a novel extrapulmonary mechanism of gas exchange via peritoneal oxygenated perfluorocarbon (PFC) in a large animal model. METHODS/STUDY POPULATION: Using two 50 kg swine, hypoxia was modeled with subatmospheric oxygen and hypercarbia induced with acute hypoventilation. Through a midline laparotomy, cannulas were placed into the peritoneal space to allow for PFC infusion and circulation. After abdominal closure, these cannulas were connected to a device capable of draining, oxygenating, and infusing PFC. One animal was subjected to acute hypoxia (12% FiO2) and another animal to acute hypoventilation (4 breaths per minute). Primary outcomes were times for SpO2 to reach 75 mmHg, respectively. Trials were performed without PFC and with PFC dwelling or circulating through the peritoneal space, during which abdominal and bladder pressures were monitored and maintained under 20 mmHg by regulation of the PFC volume contained in the animal. RESULTS/ANTICIPATED RESULTS: In the animal subjected to acute hypoxia (12% FiO2), survival time improved from 5:55 to 20:00 (min:sec) after 2.5 liters of oxygenated PFC was instilled in the peritoneal space. Oxygen percent saturation of PFC before and after dwelling in the peritoneal space was measured at 100% before and 70% after dwelling in the animal during this hypoxic period corresponding with a gas transfer of 300 mL of oxygen over the 20-minute trial (i.e., 15 mL/min). Continual PFC circulation did not further extend the survival time during hypoxic conditions over PFC dwelling in the abdomen. In the animal that was acutely hypoventilated, there were no detectable differences in the rate of CO2 accumulation as measured by EtCO2 or direct blood pCO2 measurements with PFC dwelling or circulating through the peritoneal space. DISCUSSION/SIGNIFICANCE: Oxygenated PFC dwelling in the peritoneal space increased the duration of systemic arterial blood saturation remaining greater than 50% during normobaric hypoxic (12% FiO2) conditions but did not appreciably clear blood carbon dioxide during hypoventilation. Future experiments will focus on maximizing the rate of systemic oxygen uptake.

The Effect Of Different Loads Squat Training On Energy Expenditure Of Young Women

As an important part of fitness program, resistance training is becoming more and more popular among women. However, there are few studies on the energy consumption of female resistance training. PURPOSE:Observing the energy expenditure of female squat under different loads. METHODS:Twelve women (aged 21 ± 2 years) with more than one year of resistance training experience from Beijing Sport University were selected, and the Smith squat 1RM value was more than double their body weight (79.17 ± 6.67 kg). Subjects are required to enter the laboratory 3 hours after the meal, sit and rest for 20 minutes after coming to the laboratory, and collect the oxygen intake at rest, during exercise, and 15 minutes after exercise. Subjects need to complete the Smith barbell squat with low(Smith barbell bar 4 kg and 20% 1RM), medium(40% 1RM and 60% 1RM) and high(70% 1RM and 80% 1RM) load in sequence.Subjects need to draw lots to decide and finish one of the two weight for each load.3 sets for each weight, 5 reps in each set. Squat rhythm is 2 s up and 2 s down, the interval is 4 min in the set, and the interval between different weights is 15 min. Take the peak blood lactic acid of the fingertips after exercise, calculate the difference between the blood lactic acid and the resting level, converting it to the energy consumption of 3 ml of oxygen per kilogram of body weight. RESULTS:(1) The aerobic and anaerobic glycolysis energy consumption during exercise were 5.38 ± 1.23KJ, 3.98 ± 2.25KJ. 20% 1RM were 5.17 ± 1.52KJ, 3.78 ± 1.87KJ. 40% 1RM were 5.78 ± 0.98KJ, 4.69 ± 2.22KJ. 60%1RM were 6.03 ± 1.19KJ, 6.71 ± 2.40KJ. 70% 1RM were 6.47 ± 1.23KJ, 9.37 ± 4.12KJ. 80%1RM were 6.97 ± 1.19KJ, 12.92 ± 5.52KJ. (2)Aerobic energy consumption during exercise:only the energy consumption between low and high loads has a significant difference (p < 0.05). (3) Anaerobic glycolysis energy consumption during exercise:there is a significant difference between high, low and medium load (p < 0.05), and there is no significant difference between the other loads. CONCLUSIONS:(1) The aerobic energy consumption of young women in Smith barbell squat is only significantly different from other loads energy consumption at 70% 1RM and 80% 1RM. (2) During the Smith barbell squat, the energy consumption of anaerobic glycolysis with weight below 60% of 1RM doesn’t increase with the increase in weight.

ORGANIZATION OF OXYGEN THERAPY USING A NASAL MASK AND VENTURA MASK IN SEVERE PATIENTS WITH COVID-19 CORONA VIRUS INFECTION

Oxygen is supplied to the blood by simple diffusion through the alveolo-capillary membrane, along the partial pressure gradient. With an oxygen content of about 21% in the atmospheric air, the partial pressure of oxygen in the atmosphere is about 150 mm Hg, while its content in the blood reaches 100 mm Hg. Oxygen is transported by blood in two forms: dissolved in plasma and bound to hemoglobin. 0.31 ml of O2 is dissolved in 100 ml of blood, which is not enough for tissue oxygenation. Oxygen is mainly transported in combination with hemoglobin in red blood cells: 100 ml of blood is transferred to 200 ml of oxygen. The most important parameter by which one can judge the amount of oxygen associated with hemoglobin is the saturation of hemoglobin with oxygen — SaO2, or saturation. At a partial oxygen pressure of 100 mm Hg, the saturation of hemoglobin with oxygen in arterial blood is about 97%.

Resting Oxygen Uptake Value of 1 Metabolic Equivalent of Task in Older Adults: A Systematic Review and Descriptive Analysis.

It is important for sport scientists and health professionals to have estimative methods for energy demand during different physical activities. The metabolic equivalent of task (MET) provides a feasible approach for classifying activity intensity as a multiple of the resting metabolic rate (RMR). RMR is generally assumed to be 3.5mL of oxygen per kilogram of body mass per minute (mLO2kg-1min-1), a value that has been criticized and considered to be overestimated in the older adult population. However, there has been no comprehensive effort to review available RMR estimations, equivalent to 1 MET, obtained in the older adult population. The aim of this review was to examine the existing evidence reporting measured RMR values in the older adult population and to provide descriptive estimates of 1 MET. A systematic review was conducted by searching PubMed, Web of Science, Scopus, CINAHL, SPORTDiscus, and Cochrane Library, from database inception to July 2021. To this end, original research studies assessing RMR in adults ≥ 60years old using indirect calorimetry and reporting results in mLO2kg-1min-1 were sought. Twenty-three eligible studies were identified, including a total of 1091 participants (426 men). All but two studies reported RMR values lower than the conventional 3.5mLO2kg-1min-1. The overall weighted average 1 MET value obtained from all included studies was 2.7 ± 0.6mLO2kg-1min-1; however, when considering best practice studies, this value was 11% lower (2.4 ± 0.3mLO2kg-1min-1). Based on the results of this systematic review, we would advise against the application of the standard value of 1 MET (3.5mLO2kg-1min-1) in people ≥ 60years of age and encourage the direct assessment of RMR using indirect calorimetry while adhering to evidence-based best practice recommendations. When this is not possible, assuming an overall value of 2.7mLO2kg-1min-1 might be reasonable. Systematic review registration: International Prospective Register of Systematic Reviews on 30 September 2020, with registration number CRD42020206440.

Insights into the Coadsorption and Reactivity of O and CO on Ru(0001) and Their Coverage Dependence

Using density functional theory and an exchange-correlationfunctional that includes the van der Waals interaction, we study the coadsorption of CO on Ru(0001) saturated with 0.5 ML of oxygen. Different coexisting CO coverages are considered that are experimentally motivated, the room temperaturecoverage consisting of 0.5 ML-O + 0.25 ML-CO (low coverage), the saturation coverage achieved at low temperatures (0.5 ML-O + 0.375 ML-CO, intermediate coverage), and the equally mixed monolayer that is stable according to our calculations but not experimentally observed yet (0.5 ML-O + 0.5 ML-CO, high coverage). For each coverage, we study the competition between the desorption and oxidation of CO on the corresponding optimized structure by analyzing their reaction energies and minimum energy reaction paths. The desorption process is endothermic at all coverages, although the desorption energy decreases as the CO coverage increases. The process itself (and also the reverted adsorption) becomes more involved at the intermediate and high coverages because of the appearance of a physisorption well and concomitant energy barrier separating it from the chemisorbed state. Remarkably, the oxidation of CO, which is endothermic at low coverages, turns exothermic at the intermediate and high coverages. In all cases, the minimum reaction path for oxidation, which involves the chemisorbed and physisorbed CO2, is ruled by one of the large energy barriers that protect these molecular states. Altogether, the larger activation energies for oxidation as compared to those for desorption and the extreme complexity of the oxidation against the desorption paths explain that CO desorption dominates over the oxidation in experiments.

The Influence of Temperature on Embryonic Respiration, Growth, and Sex Determination in a Western Australian Population of Green Turtles (Chelonia mydas).

The thermal environment of sea turtle embryos has marked effects on many aspects of their development and energetics and has consequences for posthatching stages. Here we incubated Chelonia mydas embryos from Ningaloo Reef in Western Australia at a range of temperatures (27°, 29°, 30°, 31°, 32°, and 30° ± 5°C) to determine development rates and the pivotal temperature for sex determination. We also measured embryonic growth, oxygen consumption, and carbon dioxide production throughout development at 27° and 31°C. Metabolic rates were higher at 31°C than at 27°C, but total energy expenditure was greater at 27°C, with 2,281 mL of oxygen consumed compared with 1,992 mL at 31°C. Respiration at both temperatures showed a pattern typical of sea turtle embryos, with peak rates occurring at approximately 85% of development and then declining toward hatching. Hatchlings produced at higher incubation temperatures developed faster, were smaller, and had larger residual yolk masses than hatchlings produced at lower temperatures. The pivotal temperature that produced an equal sex ratio was 29.2°C, with mixed sexes produced between 27.9° and 30.4°C. Our results showed that the Ningaloo population of C. mydas has somewhat different thermal sensitivities than other C. mydas populations and justified why is it necessary to collect population-specific data to accurately project the impacts of global warming on focal populations.

Hemoglobin Is a Vital Determinant of Arterial Oxygen Content in Hypoxemic Patients with Pulmonary Arteriovenous Malformations.

PaO2 and SaO2 are commonly measured in respiratory practice, but arterial oxygen content (CaO2) refers to the volume of oxygen delivered to the tissues per unit blood volume. CaO2 is calculated from SaO2 and the hemoglobin concentration in blood, recognizing that each gram of hemoglobin can transport approximately 1.34 ml of oxygen when fully saturated. To prospectively evaluate serial changes in CaO2 in humans, incorporating and excluding dynamic changes to oxygenation and hemoglobin parameters that may occur during life. A cohort of 497 consecutive patients at risk of both hypoxemia and anemia were recruited. The patients had radiologically proven pulmonary arteriovenous malformations (PAVMs), which result in hypoxemia due to right-to-left shunting, and concurrent hereditary hemorrhagic telangiectasia, which placed them at risk of iron deficiency anemia due to recurrent hemorrhagic iron losses. Presentation SaO2 (breathing room air, by pulse oximetry), hemoglobin, red cell and iron indices were measured, and CaO2 calculated as SaO2 × hemoglobin × 1.34 ml/g. Serial measurements were evaluated in 100 cases spanning up to 32.1 (median, 10.5) years. Presentation CaO2 ranged from 7.6 to 27.5 (median, 17.6) ml/dl. CaO2 did not change appreciably across the SaO2 quartiles. In contrast, hemoglobin ranged from 5.9 to 21.8 g/dl (median, 14.1 g/dl), with a linear increase in CaO2 across hemoglobin quartiles. After PAVM embolization and an immediate increase in SaO2, hemoglobin fell and CaO2 was unchanged 1.6-12 (median, 4) months later. When hemoglobin fell because of iron deficiency, there was no change in SaO2. Similarly, when hemoglobin rose after iron treatment, there was no change in SaO2, and the expected CaO2 increment was observed. These relationships were not evident during pregnancy when hemoglobin fell, and PAVMs usually deteriorated: in pregnancy SaO2 commonly increased, and serial CaO2 values (incorporating hemodilution/anemia) more accurately reflected deteriorating PAVM status. An apparent fall in CaO2 with age in females was attributable to the development of iron deficiency. There was an unexplained increase in CaO2 with age in follow-up of males after embolization. Hemoglobin/CaO2 should be further incorporated into oxygenation considerations. More attention should be given to modest changes in hemoglobin that substantially modify CaO2.

The place of goal-directed haemodynamic therapy in the 21st century

### Key points This article will discuss the history and subsequent development of goal-directed haemodynamic therapy (GDT), reviewing briefly the significant clinical trials of GDT, and finally suggest a practical clinical guide to GDT based on the most up-to-date evidence synthesis. The future role for GDT will also be discussed. The ‘high-risk’ surgical patient may be classified in a variety of ways. One suggested threshold includes those patients who have an individual postoperative mortality risk exceeding 5%, incorporating surgical factors such as complexity and urgency (often emergency), and patient factors such as comorbidities and (increasing) age.1 ‘Extremely high-risk’ patients are those whose postoperative mortality risk is >20%.2 Another classification describes those patients undergoing procedures that carry an inherent mortality rate exceeding 5%. Twenty-five per cent of the surgical population undergoing vascular, upper gastrointestinal, lower gastrointestinal, and hepatobiliary surgery fall into this latter category.3 Measures of cardiovascular fitness can also be used to stratify patient risk. Patients unable to achieve four metabolic equivalents (METS) (such as climbing a flight of stairs or gardening) are designated high risk, as are those with an anaerobic threshold (AT) of <11 ml of oxygen per kilogram per minute (ml O2 kg−1 min−1) on preoperative cardiopulmonary …

DFT Study of Chemisorbed Atomic Oxygen Inducing Co Segregation in CoNi(111) Alloy

Chemisorbed atomic oxygen inducing Co segregation in CoNi (111) alloy is studied using periodic self-consistent density functional theory (DFT) calculations. In particular, the coverage dependence and possible adsorption-induced segregation phenomena are addressed by investigating segregation energies (the difference in calculated total free energy between surface sites and bulk-like sites) of isolated Co in CoNi (111) alloy. In agreement with previous experimental and theoretical investigations, segregation of Co is found to be oxygen-coverage dependent. While for ‘clean’ CoNi (111), Co prefers to be in the bulk. In the presence of more than 2/9 ML of oxygen, Co segregates to the surface. The analysis of oxygen adsorption trends and surface electronic structures explains the change in the local atomic arrangement which is expected to occur on the surface of alloys under reaction conditions. Our predictions for the high oxygen coverage cases are particularly relevant in underlining the importance of segregation phenomena to the hydrogen evolution performance of CoNi alloy hydrogen evolution electrode.

Некоторые особенности ответа организма на локальное введение активных форм кислорода

The purpose of this work is the study of microcirculation state at different local effects of reactive&#x0D; oxygen species on animal tissues. The experiment was performed on 60 healthy white Wistar rats. Control&#x0D; group (without any manipulations) included 20 Wistar rats. Also 4 main groups were formed (10 rats in each).&#x0D; Rats of the first group (n=10) were intracutaneously injected with 1 ml of oxygen (in the back), a local darsonvalization&#x0D; during 4 min. was carried out in animals of the second group (n=10). In third group (n=10) the injection&#x0D; of 1 ml of oxygen-ozone mixture was made, in the fourth group (n=10) - darsonvalization during 4 min. after a&#x0D; preliminary introduction of oxygen (1 ml). Microcirculation parameters were tested by laser Doppler flowmetry&#x0D; with LAKK-02 device. It was defined, that local effects of reactive oxygen species include microcirculation&#x0D; changes, depending from specialties of exposed factor.

Hypoxaemia, sport and polycythaemia: a case from Imperial College London

WY : An 18-year-old footballer with no previous significant medical history sustained a tendon injury during a football match. This was repaired successfully under general anaesthetic, but the SaO2 (%...

Exercise Therapy in Cardiac Rehabilitation

Exercise is integral part of rehabilitation programme. It is necessary for optimal physical functioning and psychological wellbeing. It has a direct positive effect on maximal oxygen capacity increasing cardiac output, decreasing blood lipids, decreasing blood pressure, increasing blood flow through the coronary arteries, increasing muscle mass flexibility, improving psychological state and assisting weight loss and control. A regular schedule of moderate exercise even after many years of sedentary living is beneficial. One method used to identify levels of physical activities is through metabolic equivalent (MET) units. 1 MET is the amount of oxygen needed by the body at rest -3.5 ml of oxygen per kilogram per minute. In the hospital, the activity level is gradually increased so that time of discharge the patient can tolerate moderate energy activities of 3–5 MET.

Haemoglobin concentration and mass as determinants of exercise performance and of surgical outcome

The ability of the cardiorespiratory system (heart, lungs, blood) to deliver oxygen to exercising skeletal muscle constrains maximum oxygen consumption , with cardiac output and the concentration of oxygen-carrying haemoglobin ([Hb]) being key limiting parameters. Total blood volume (BV) is the sum of the plasma volume (PV) and the total red cell volume. The measured [Hb] is dependent upon the total circulating mass of haemoglobin (tHb-mass) and plasma volume (PV). While the proportion of oxygen carried in plasma is trivial (0.3 mL of oxygen per 100 mL of plasma), each gram of Hb, contained in red blood cells, binds 1.39 mL of oxygen. As a result, the relationship between and tHb-mass is stronger than that observed between and [Hb] or BV. The glycoprotein hormone erythropoietin drives red cell synthesis and, like simple transfusion of packed red blood cells, can increase tHb-mass. An iron-containing haem group lies at the centre of the Hb molecule and, in situations of actual or functional iron deficiency, tHb-mass will also rise following iron administration. However achieved, an increase in tHb-mass also increases circulating oxygen-carrying capacity, and thus the capacity for aerobic phosphorylation. It is for such reasons that alterations in and exercise performance are proportional to those in arterial oxygen content and systemic oxygen transport, a change in tHb-mass of 1 g being associated with a 4 mL · min−1 change in . Similarly, increases by approximately 1% for each 3 g · L−1 increase in [Hb] over the [Hb] range (120 to 170 g · L−1). Surgery, like exercise, places substantial metabolic demands on the patient. Whilst subject to debate, oxygen supply at a rate inadequate to prevent muscle anaerobiosis may underpin the occurrence of the anaerobic threshold (AT), an important submaximal marker of cardiorespiratory fitness. Preoperatively, cardiopulmonary exercise testing (CPET) can be used to determine AT and peak exertional oxygen uptake ( peak) as measures of ability to meet increasing oxygen demands. The degree of surgical insult and the ability to meet the resulting additional postoperative oxygen demand appear to be fundamental determinants of surgical outcome: individuals in whom such ability is impaired (and thus those with reduced peak and AT) are at greater risk of adverse surgical outcome. This review provides an overview of the relationships between [Hb], tHb-mass, exercise capacity, and surgical outcome and discusses the potential value of assessing tHb-mass over [Hb].

Emergent Cardiopulmonary Bypass for a 180 Kilogram Patient: Support with a Single Oxygenator

As obesity increases in prevalence, so will cases in which patients present at the boundaries of care. We report the support of a class III obese man, having a body mass index of 60.8 kg/m2 and in acute renal failure, with a single Trillium™-coated Affinity® NT Hollow Fiber oxygenator in cardiopulmonary bypass for an emergent aortic valve replacement secondary to infective endocarditis. A maximum oxygen delivery of 807.51 mL of oxygen per minute is reported for this oxygenator in this case report.

Physical Activity and Structured Exercise for Patients With Stable Ischemic Heart Disease

EXERCISE WAS RECENTLY DESCRIBED AS “A MIRACLE drug” that can benefit every part of the body and substantially extend lifespan.” The authors suggested that the cardioprotective and systemic health benefits of regular exercise are underestimated by many clinicians, who often fail to emphasize the importance of regular physical activity, as well as the harms of physical inactivity, even though they routinely counsel patients about other modifiable cardiovascular risk factors, such as cigarette smoking, elevated cholesterol levels, and hypertension. If exercise is a central and indispensible component of a comprehensive strategy for the primary prevention of coronary artery disease, the mantra “exercise is medicine” may be even more valid and is too often undervalued as a critical element in secondary prevention. However, many patients with heart disease who qualify for and require exercise training as an essential part of their recovery process are not receiving this therapy, often because of a lack of awareness by patients, health care professionals, and payers of the necessity, appropriateness, and effectiveness of this intervention. This gap between scientific evidence and clinical practice is the focus of this Viewpoint, which discusses the importance of structured exercise and increased physical activity for patients with stable ischemic heart disease and the need to highlight the poor prognosis associated with being in the least fit, least active cohort (bottom 20%) for the 12 to 13 million US residents who comprise this population. One of the most puzzling aspects of the medical community’s failure to recommend regular exercise for patients with stable ischemic heart disease may be the fundamental simplicity and affordability of this intervention, particularly compared with other widely accepted preventive measures. For instance, the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial showed no difference in clinical outcomes in patients with stable ischemic heart disease (eg, death, myocardial infarction, hospitalization for unstable angina) during a mean 55-month follow-up between those who underwent percutaneous coronary intervention (PCI) and optimal medical therapy (including both risk-reducing and symptom-reducing therapies) and those treated with optimal medical therapy and lifestyle modification. Anginal symptoms were reduced in both groups, and there was no significant difference in health status between the groups, demonstrating that optimal control of risk factors could favorably affect outcomes. Despite clinical guideline recommendations that, among patients with stable ischemic heart disease, revascularization may be deferred until the effects of optimal medical therapy and lifestyle modification have been assessed and validated, more than half of the 1.3 million annual PCI procedures in the United States are performed electively for patients with stable ischemic heart disease, and only about 45% of these patients receive optimal medical therapy prior to their procedure. Equally concerning is that many of these patients do not participate in medically supervised or home-based exercise training programs, even after revascularization. Increased exercise or physical activity and cardiorespiratory fitness appear to mitigate cardiovascular disease progression. Exercise has antiatherosclerotic, antithrombotic, anti-ischemic, antiarrhythmic, and positive psychological effects, and secondary prevention exercise training regimens in conjunction with optimal medical therapy have been shown to reduce total mortality by 20%, cardiac mortality by 26%, and nonfatal myocardial infarction by 21%. Cardiorespiratory fitness may be expressed as metabolic equivalents (METs), for which 1 MET isapproximately 3.5 mL of oxygen per kilogram of body weight per minute (mL/kg/ min), which is equivalent to the energy requirement for basal homeostasis. Multiples of this value are often used to quantify relative levels of energy expenditure. Each 1-MET increase in exercise capacity is associated with an 8% to 35% (median, 16%) reduction in mortality, which compares favorably with the survival benefit conferred by low-dose aspirin, statins, -blockers, and angiotensin-converting enzyme inhibitors after acute myocardial infarction. Current guidelines recommend 30to 60 minutes of moderate-intensity aerobic activity at least 5 days a week for patients with stable ischemic heart disease to augment peak oxygen uptake and modify cardiovascular risk factors, as well as complementary resistance training at least 2 days a week to increase weight-carrying tolerance and skeletal muscle strength. Resistance training also attenuates the rate-

Chemisorbed atomic oxygen inducing Pd segregation in PdAu(1 1 1) alloy: Energetic and electronic DFT analysis

Segregation energies of isolated Pd in PdAu(111) alloy are investigated by DFT calculations as a function of the oxygen coverage. Segregation of Pd is found to be oxygen-coverage dependent. While for ‘clean’ PdAu(111), Pd prefers to be in the bulk, in the presence of more than 1/3 ML of oxygen, Pd meanly segregates to the surface. The analysis of Pd d-band provides evidence of strong Pd–O affinity. The understanding of such behaviour is of interest in the field of heterogeneous catalysis because of the lack of information about the surface ordering in bimetallic alloys in the presence of reactive gas.

Local Bonding Effects in the Oxidation of CO on Oxygen-Covered Au(111) from Ab Initio Molecular Dynamics Simulations.

A fully dynamical approach using ab initio molecular dynamics (AIMD) simulations is applied to the investigation of CO oxidation on O-covered Au(111). We investigate how the activity of gold depends upon temperature, oxygen coverage, and surface structure. On clean Au(111) at 500 K, CO binds transiently on top of Au atoms, spending a small fraction (∼7%) of the total simulation time adsorbed on the surface. The presence of O on the surface increases the residence time for CO by more than 4 times on a surface containing 0.22 ML of O. On the other hand, the probability for CO adsorption decreases with oxygen coverage from 31% at 0.22 ML of oxygen to 15% at 0.55 ML of oxygen. Our simulations show that the activity for CO reaction with O to yield CO2 decreases with increasing oxygen coverage. We attribute this decrease of activity to (1) the decrease in the CO adsorption probability as the oxygen coverage increases and (2) the decreasing amount of reactive chemisorbed oxygen (oxygen bound in a 3-fold site) with increasing total oxygen coverage. We show that oxygen bound in sites of local 3-fold coordination (chemisorbed oxygen) is nearly 2 times more reactive than other oxygen species observed on the surface, namely, surface and subsurface oxide. Our work demonstrates the value and feasibility of using AIMD to study surface reactions.

Effect of resistance exercise during hemodialysis on physical function and quality of life: randomized controlled trial

The objective of this study was to determine whether 24 weeks resistance training during hemodialysis could improve exercise capacity, muscle strength, physical functioning and health-related quality of life compared to a low intensity aerobic program. 27 patients (55.6 +/- 17.6 years) were recruited from two hemodialysis clinics in Valencia (Spain). Patients were randomized to resistance training (n = 19) or low-intensity aerobic training (n = 8). Resistance training consisted of three sets of 4 exercises at an intensity of 12 - 15 out of 20 at the rate of perceived exertion scale (Borg scale measuring self-rated exercise intensity) using weights and elastic bands on every session during 24 weeks. Primary outcomes included physical performance tests, evaluated by the "sit-to-stand-to-sit tests" and the 6 minutes walking test, and knee extensor muscles strength, evaluated by isometric dynamometry. Secondary outcomes included cardiorespiratory fitness, measured by time and METs (measure of energy expenditure as ml of oxygen per kg of weight and per minute; 1 MET is equal to 3.5 ml O(2)/kg/min) achieved on a graded exercise test, and quality of life, measured by the SF-36 questionnaire. No differences were noted in change-over-time between the two groups in any of the physical performance tests. However, a significant change was found in change-over-time in right knee extensor muscles dynamometry, and intragroup analysis showed a significant improvement in resistance training groups in the physical performance tests and METs. These findings suggest that resistance training during hemodialysis improves patient's physical functioning.