Search results for "Pressure"

Divinyl Sulfone Cross-Linked Hyperpolymeric Human Haemoglobin as an Artificial Oxygen Carrier in Anaesthetized Spontaneously Breathing Rats

1994

Hyperpolymeric haemoglobin in concentrations necessary to transport oxygen in organism to a significant extent exhibits a negligible oncotic pressure as compared to that of plasma. This property makes hyperpolymeric haemoglobins suitable for development of an artificial oxygen transporting blood additive. With such an additive - in contrast to an oxygen transporting plasma expander - combating a chronic oxygen deficit of tissue (brain, heart, kidney, extremities or in case of anaemia) is possible. Using in these cases an isoncotic oxygen carrying plasma expander instead of an additive would be even more detrimental because of fluid load to heart, at least in case of heart injury. Chronic ox…

Molar masses and structure in solution of haemoglobin hyperpolymers--a common calibration of size exclusion chromatography of these artificial oxygen…

1997

We are developing artificial oxygen carriers for medical use, based on synthetic polymers--so-called hyperpolymers--obtained by cross-linking mammalian haemoglobins. One requirement with respect to the polymers is that they should not increase the oncotic pressure of blood remarkably--this can be realized by high molecular weights of the polymers with a narrow distribution. They may act as a oxygen transporting blood additive, and--in combination with a plasma expander--as a blood substitute. Another important and desired property of the artificial oxygen carrier is a low viscosity, which--first--is due to a high degree of uniformity of the polymer size (or molar mass) distribution and--sec…

Wet BNP, fluid and hemodynamic status at discharge in Acute Heart Failure

2010

We comment the noteworthy results of Pimenta et al. concerning the significance of discharge BNP levels in acute HF patients. The innovation of Pimento's study is the systematic research of the potential relationship between BNP and clinical and hemodynamic parameters. We focused the attention on the importance of wet "BNP" in managing HF and its ability to reflect congestion and multiple underlying patho-physiological disturbances. The first observation, regarding the statistical order, underlines the importance of renal insufficiency at discharge in genesis of higher BNP levels. Secondly, we note that the relationship between natriuretic peptides and the non-invasive measurement of the fl…

Topical glaucoma medications – Clinical implications for the ocular surface

2022

Glaucoma is a leading cause of irreversible blindness. The use of topical eye drops to reduce intraocular pressure remains the mainstay treatment. These eye drops frequently contain preservatives designed to ensure sterility of the compound. A growing number of clinical and experimental studies report the detrimental effects of not only these preservatives but also the active pharmaceutical compounds on the ocular surface, with resultant tear film instability and dry eye disease. Herein, we critically appraise the published literature exploring the effects of preservatives and pharmaceutical compounds on the ocular surface. publishedVersion

High flow nasal therapy in perioperative medicine: from operating room to general ward

2018

Abstract Background High flow nasal therapy (HFNT) is a technique in which humidified and heated gas is delivered to the airways through the nose via small nasal prongs at flows that are higher than the rates generally applied during conventional oxygen therapy. The delivered high flow rates combine mixtures of air and oxygen and enable different inspired oxygen fractions ranging from 0.21 to 1. HFNT is increasingly used in critically ill adult patients, especially hypoxemic patients in different clinical settings. Main body Noninvasive ventilation delivers positive pressure (end-expiratory and inspiratory pressures or continuous positive airway pressure) via different external interfaces. …

Hyperventilation in Severe Traumatic Brain Injury Has Something Changed in the Last Decade or Uncertainty Continues? A Brief Review

2021

Photonic-crystal fiber-based pressure sensor for dual environment monitoring.

2014

In this paper the development of a side-hole photonic-crystal fiber (SH-PCF) pressure sensor for dual environment monitoring is reported. SH-PCF properties (phase and group birefringence, sensitivity to pressure variations) are measured and compared to simulated data. In order to probe two environments, two sections of the SH-PCF with different lengths are spliced and set in a Solc filter-like configuration. This setup allows obtaining the individual responses of the first and second fiber independently, which is useful for a space-multiplexed measurement. As the employed fiber is sensitive to pressure variations, we report the use of this configuration for dual environment pressure sensing.

Optical experiments on a crystallizing hard-sphere–polymer mixture at coexistence

2010

We report on the crystallization kinetics in an entropically attractive colloidal system using a combination of time resolved scattering methods and microscopy. Hard sphere particles are polystyrene microgels swollen in a good solvent (radius a=380nm, starting volume fraction 0.534) with the short ranged attractions induced by the presence of short polymer chains (radius of gyration rg = 3nm, starting volume fraction 0.0224). After crystallization, stacking faulted face centred cubic crystals coexist with about 5% of melt remaining in the grain boundaries. From the Bragg scattering signal we infer the amount of crystalline material, the average crystallite size and the number density of cry…

Process parameters calibration in 3D tube hydroforming processes

2007

In tube hydroforming the concurrent actions of pressurized fluid and mechanical feeding allow to obtain tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. What is crucial in such processes is the proper design of operative parameters aimed to avoid defects (for instance shape defects or ductile fractures). The main process parameters are material feeding history (i.e. the punches velocity history) and internal pressure path during the process. In more complex three dimensional processes, also the action of a counterpunch is generally useful to reduce thinning in particular in expansion zones of the tube (i.e. T or Y shaped tubes). The g…

Design of concave and convex paired sloped drip laterals

2017

Abstract Properly designed microirrigation plants allow water use efficiency to be optimized and quite high values of emission uniformity to be obtained in the field. Disposing paired laterals so that two distribution pipes extend in opposite directions from a common manifold contributes to provide more uniform pressure to all laterals in thesystem. Towards this end, an analytical procedure to optimize the uniform pressure when designing paired drip laterals on uniform slopes has recently been proposed, based on the assumption that the variations of the emitters’ flow rate along the lateral and the local losses due to the emitters’ insertions could be neglected. More recently, an easy metho…