Search results for "Urethane"

Acetylcholine release in the hippocampus of the urethane anaesthetised rat positively correlates with both peak theta frequency and relative power in…

2000

The need to achieve a clearer understanding of relations between hippocampal theta characteristics and cholinergic septohippocampal neuron activity, prompted us to re-examine, in the urethane-anaesthetised rat, the statistical relationships between the electrophysiological and neurochemical variables using a procedure which is believed to enhance significantly the degree of confidence with which parameters of theta recorded with classic macroelectrodes can be related to concomitant acetylcholine output measured by high-performance liquid chromatography with electrochemical detection. Firstly, the theta rhythm and the acetylcholine content were derived from the same hippocampus. Secondly, th…

Coupling between simultaneously recorded BOLD response and neuronal activity in the rat somatosensory cortex

2007

Abstract Understanding the link between the hemodynamic response and the underlying neuronal activity is important for interpreting functional magnetic resonance (fMRI) signals in human and animal studies. Simultaneous electrophysiological and functional imaging measurements provide a knowledge of information processing and communication in the brain with high spatial and temporal resolution. In this study, a range of neural and blood oxygenation level-dependent (BOLD) responses were elicited in the rat somatosensory cortex by changing the type of anesthesia (urethane or alpha-chloralose) and the electrical forepaw stimulus frequency (1–15 Hz). Duration of the stimulus was 30 s. Electrical …

Permanent stenting in “unextractable” common bile duct stones in high risk patients. A prospective randomized study comparing two different stents

2007

BACKGROUND: Endoscopic sphincterotomy (ES) and stone extraction is the treatment of choice for bile duct stones. Therefore, if ES and conventional stone extraction fail, further treatment is mandatory. Insertion of a biliary endoprosthesis is an effective option. MATERIALS AND METHODS: We treated 30 high-risk patients (17 women and 13 men, mean age 82 years) affected by difficult common bile duct stones. The patients were randomly assigned preoperatively using closed envelopes (blind randomization) into two groups to receive insertion of polyethylene or hydrophilic hydromer-coated polyurethane stent, respectively. Follow-up was achieved by contacting referring physicians and patient's relat…

Auditory‐evoked potentials to changes in sound duration in urethane‐anaesthetized mice

2019

Spectrotemporally complex sounds carry important information for acoustic communication. Among the important features of these sounds is the temporal duration. An event-related potential called mismatch negativity indexes auditory change detection in humans. An analogous response (mismatch response) has been found to duration changes in speech sounds in rats but not yet in mice. We addressed whether mice show this response, and, if elicited, whether this response is functionally analogous to mismatch negativity or whether adaptation-based models suffice to explain them. Auditory-evoked potentials were epidurally recorded above the mice auditory cortex. The differential response to the chang…

Prospective, randomized, single-center trial comparing 3 different 10F plastic stents in malignant mid and distal bile duct strictures.

2003

Abstract Background: The aim of this study was to determine whether patency rates differ with respect to the material, design, and surface texture of 3 different plastic stents. Methods: A total of 120 patients (median age 70.5 years; interquartile range 62-78 years) with malignant mid or distal bile duct strictures, seen between March 1996 and May 1999, were prospectively randomized to receive a 10F polyurethane stent, a Teflon Tannenbaum stent, or a hydrophilic hydromer-coated polyurethane stent. The primary study outcome measure was the interval between stent insertion and the first episode of clogging (or the presence of jaundice at death without stent exchange). All 3 types of stent we…

Elastomeric Electrospun Polyurethane Scaffolds: The Interrelationship Between Fabrication Conditions, Fiber Topology, and Mechanical Properties

2010

Electrospinning has been gaining increasing popularity in the fabrication of engineered tissue scaffolds due to its ability to produce nano to micro scale fibrous sheets. Many investigators have attempted to apply various degrees of control to this process in order to produce fiber meshes with more predictable patterns. These attempts have largely been limited to controlling fiber alignment and have fallen into two categories: physical manipulation of the fibers by pulling them into alignment using a rapidly spinning mandrel[1–3] or manipulation of the electric field during fabrication.[4, 5]

Effect of Poly(Titanium Oxide) on the Viscoelastic and Thermophysical Properties of Interpenetrating Polymer Networks

2021

The authors thank V. Serga for many useful discussions. The research was (partly) performed in the Institute of Solid State Physics, University of Latvia ISSP UL. ISSP UL as the Center of Excellence is supported through the Framework Program for European universities Union Horizon 2020, H2020-WIDESPREAD-01–2016–2017-Teaming Phase 2 under Grant Agreement No. 739508, CAMART2 project.

Thermostability of polymeric langmuir-blodgett films

1991

Effect of chain extender on the morphology, thermal, viscoelastic, and dielectric behavior of soybean polyurethane

2021

An experimental method for the investigation of rigid polyurethane foams in shear

2018

Widespread applications of rigid polyurethane and plastic foams lead to shear deformations. Therefore, methods for ensuring shear using experimental investigations are necessary, including the possibility of determining the shear modulus, strength and limit angle. Therefore, a device that allows investigating the shear properties of highly porous plastic foams was developed. The proposed device comprises a clip-on extensometer, commonly exploited in uni-axial compression/tension tests, for the determination of the shear displacement directly on the foams’ sample, on a measurement zone of certain dimensions and location. An innovative construction of the extensometer’s legs is elaborated, p…