Tumours that are low in oxygen (hypoxic) tend to be more aggressive and respond less well to treatment. Knowing the spatial distribution of oxygen within a tumour could therefore play an important role in treatment planning, enabling treatment to be targeted in such a way that higher doses of radiation are given to the more radioresistant tissue. Mapping the spatial distribution of oxygen in vi...

Hummingbirds evolved during a period of decline in atmospheric oxygen concentration and currently encounter varying levels of oxygen availability along their elevational distribution. We tested the hypothesis that inspiration of hyperoxic gas increases hummingbird hovering performance when birds are simultaneously challenged aerodynamically. We measured the maximum duration of hovering flight w...

The interaction of singlet oxygen (O2) generated in a photosensitized process with well-known reference photosensitizers Perinaphthenone (PN) and TMPyP is investigated in a model system consisting of fatty acids and the respective exogenous photosensitizer (PS) in solution by direct detection of the luminescence photons of O2 at 1270 nm. Such a model system is a first approach to mimic the comp...

the accurate estimation of reaeration rate coefficient, because of its effects on dissolved oxygen in rivers, is one of the most important initial steps of water quality management. the main goal of this paper is to evaluate the effects of reaeration rate coefficient on the river water dissolved oxygen, case study dinachal river, iran. to achieve these aims, water quality samples were collected...

The interactions between oxygen permeation and homogeneous fuel oxidation reactions on the sweep side of an ion transport membrane (ITM) are examined using a comprehensive model, which couples the dependency of the oxygen permeation rate on the membrane surface conditions and detailed chemistry and transport in the vicinity of the membrane. We assume that the membrane surface is not catalytic t...

OBJECTIVE To compare the effects on transcutaneous carbon dioxide tension (Ptco2) of high concentration and titrated oxygen therapy in medical inpatients with morbid obesity who were not selected for a pre-existing diagnosis of obesity hypoventilation syndrome. DESIGN A randomised, crossover trial undertaken between February and September 2015. SETTING Internal medicine service, Wellington ...

Two groups of 10 patients were studied during artificial ventilation with a mixture of oxygen, nitrogen and either halothane or trichloroethylene. Arterial blood and respiratory gas smapling was performed at FIO2 values of 0.33, 0.5 and 0.75. The efficiency of oxygen transfer, expressed as the difference between pulmonary end-capillary and arterial oxygen content, was found to decrease progress...

The inspired oxygen concentration (F/O2) was changed on 43 occasions at about 30-min intervals in 13 patients during artificial ventilation with mixtures of nitrous oxide (N2O), oxygen and halothane. Ventilator settings remained unchanged for each patient and at the end of each period, samples of arterial and central venous blood (and, in six patients, pulmonary arterial blood) and inspired and...

BACKGROUND The likely values of inspired oxygen concentration (FIO2) of patients with chronic obstructive pulmonary disease breathing via nasal cannulas have not been assessed previously. METHODS Seven patients with chronic obstructive lung disease and seven healthy subjects were studied while breathing oxygen via nasal cannulas or fixed performance (Venturi) or uncontrolled (MC) oxygen masks...

Optical methods using phosphorescence quenching by oxygen are suitable for sequential monitoring and non-invasive measurements for oxygen concentration (OC) imaging within cells. Phosphorescence intensity measurement is widely used with phosphorescent dyes. These dyes are ubiquitously but heterogeneously distributed inside the whole cell. The distribution of phosphorescent dye is a major disadv...