Search results for "oxygenation"
showing 10 items of 237 documents
ReO as a Brønsted acidic modifier in glycerol hydrodeoxygenation : Computational insight into the balance between acid and metal catalysis
2023
A computational study for the competitive conversion of glycerol to 1,2-propanediol and 1,3-propanediol is presented, considering a two-step sequence of dehydration followed by hydrogenation. The elementary steps for dehydration, i.e., breaking of C–H followed by C–OH or vice versa, were studied computationally both on the Rh metal surface and the acid-modified ReOH–Rh surface in order to understand the role of the acid promoter. While the acid modifier can catalyze the C–OH cleavage, the activation energy for the C–H cleavage was found to be considerably smaller on both pure and acid-doped Rh(111) surfaces, and breaking the secondary C–H bond is kinetically favored over breaking the termin…
Tumour oxygenation during fractionated radiotherapy--comparison with size-matched controls.
1999
The effect of fractionated irradiation on the oxygenation status of experimental tumours was investigated using polarographic assessment of the pO2 distribution. Since an improvement in tumour oxygenation could simply be the result of tumour shrinkage, a comparison of pO2 readings of untreated size-matched control tumours was performed. Irradiation was carried out using 6 fractions of 6 Gy applied within 11 days. A comparison of polarographic pO2 data with size-matched untreated tumours revealed a significant improvement in oxygenation after the irradiation. The median pO2 was 0.9+/-0.1 mm Hg for unirradiated tumours at a volume of 180 mm3, while the corresponding data for irradiated tumour…
Implementation of veno-venous extracorporeal membrane oxygenation in a COVID-19 convalescent
2020
Lung density distribution in dynamic CT correlates with oxygenation during pressure-controlled ventilation of pigs with lavage-ARDS
2000
Tumor Oxygenation Under Normobaric and Hyperbaric Hyperoxia
1997
Tumor hypoxia is an important factor limiting the efficiency of sparsely ionizing ra-diation and O2-dependent chemotherapy. Since the tumor pO2 is the result of a dynamic steady state between oxygen supply and O2 consumption of the tumor tissue, hypoxia could be reduced either by increasing the O2-supply or by reducing the O2 demand of the tumor cells. The O2 supply can be improved for instance by (i) increasing the arterial oxy-gen partial pressure, (ii) improving (and homogenizing) the tumor perfusion, or (iii) en-hancing the O2 release from blood into the tissue by right-shifting the HbO2 dissociation curve. Theoretically, it should also be possible to improve tumor oxygenation by a rela…
The Effect of Erythropoietin on Tumor Oxygenation in Normal and Anemic Rats
1994
Anemia associated with malignancy is a common clinical problem. Its etiology is varied and includes nutritional causes, hemorrhage, hemolysis, bone marrow metastasis and hypoplasia, paraneoplastic syndromes, and chemotherapy1, with many patients presenting with anemia even before they receive cytotoxic therapy and even if their bone marrow is not invaded by tumor cells2. The response of tumors to standard radiotherapy and oxygen-dependent chemotherapy in these patients is often less satisfactory than in subjects with normal hemoglobin levels3. This is presumed to be due to the worsening of tumor oxygenation as a result of the decreased oxygen-carrying capacity of the blood in these anemic t…
Accuracy Of Non-Invasive Methods For The Evaluation Of Oxygenation Status In Community-Acquired Pneumonia: Comparison Of PaO2/FiO2 Calculated From Se…
2012
Muscle Oxygen Delivery in the Forearm and in the Vastus Lateralis Muscles in Response to Resistance Exercise: A Comparison Between Nepalese Porters a…
2020
Altitude ascending represents an intriguing experimental model reproducing physiological and pathophysiological conditions sharing hypoxemia as the denominator. The aim of the present study was to investigate fractional oxygen extraction and blood dynamics in response to hypobaric hypoxia and to acute resistance exercises, taking into account several factors including different ethnic origin and muscle groups. As part of the “Kanchenjunga Exploration & Physiology” project, six Italian trekkers and six Nepalese porters took part in a high altitude trek in the Himalayas. The measurements were carried out at low (1,450 m) and high altitude (HA; 4,780 m). Near-infrared spectroscopy (NIRS)-d…
Near-Infrared Hemoencephalography for Monitoring Blood Oxygenation in Prefrontal Cortical Areas in Diagnosis and Therapy of Developmental Dyslexia
2013
The purpose of this study was to check empirically the relevance of the near-infrared hemoencephalography (NIR-HEG), which assesses local brain blood oxygenation, in facilitation of the diagnosis and behavioral therapy in dyslexics. The study was carried out in children and teenagers with physiologically recognized dyslexia, of three increasing age-groups: 6–7, 9–10, and 19–20 years old. Healthy age- and gender-matched subjects were used as controls. Left and right prefrontal cortical areas were targeted for the NIR-HEG measurements that were taken at baseline in both controls and dyslexics and then after a 10-day course of midriff breathing exercise combined with a standard vocal and writi…