Search results for "Mixture"
showing 10 items of 1178 documents
The enantiomers of phenprocoumon: pharmacodynamic and pharmacokinetic studies.
1976
The pharmacodynamics and pharmacokinetics of the optical enantiomers of phenprocoumon were studied in 5 normal subjects and compared to the racemic mixture. Each subject received a single oral dose of 0.6 mg/kg of racemic, S(-), and R(+) phenprocoumon. S(-) phenprocoumon was 1.6 to 2.6 times as a potent as R(+) phenprocoumon when the area under the effect/time curve was used to quantify the total anticoagulant effect per dose. Comparing the plasma concentrations that elicited the same anticoagulant effect, S(-) phenprocoumon was 1.5 to 2.5 times as potent as R(+) phenprocoumon. The anticoagulant activity of the racemic mixture was between that of the enantiomers. There was no distinct diffe…
Rasch validation of the Depression Scale among patients with low back pain.
2020
BACKGROUND: The Depression Scale (DEPS) is a commonly used screening tool for major depression in studies investigating low back pain, yet it has not been validated for patients with back-specific problems. OBJECTIVE: To assess the psychometric properties of the DEPS in patients with degenerative spinal disease. METHODS: Six hundred and thirty-seven patients with a degenerative spinal disease completed the DEPS instrument. The Rasch Measurement Theory was applied to analyze the measurement properties of the DEPS. The main hypothesis-driven approach was whether the DEPS would meet relevant psychometric criteria for assessing depressive symptoms among patients with degenerative spinal disease…
Oral cancer associated with chronic mechanical irritation of the oral mucosa
2017
Background Most of the studies dealing with Chronic Mechanical Irritation (CMI) and Oral Cancer (OC) only considered prosthetic and dental variables separately, and CMI functional factors are not registered. Thus, the aim of this study was to assess OC risk in individuals with dental, prosthetic and functional CMI. Also, we examined CMI presence in relation to tumor size. Material and Methods A case-control study was carried out from 2009 to 2013. Study group were squamous cell carcinoma cases; control group was patients seeking dental treatment in the same institution. Results 153 patients were studied (Study group n=53, Control group n=100). CMI reproducibility displayed a correlation coe…
Anti-diphtheria antibody seroprotection rates are similar 10 years after vaccination with dTpa or DTPa using a mathematical model
2003
The reduced antigen content diphtheria, tetanus and pertussis (dTpa) vaccine (Boostrixtrade mark) has been shown to induce a strong booster response to all the vaccine components in 4-6 year olds. However, anti-diphtheria antibody levels were observed to be lower when compared to the "full strength" paediatric DTPa vaccine. To assess the impact of this difference on long-term protection, a mathematical model was developed to predict diphtheria antibody decay over time. The model was based on a linear decrease in log-transformed antibody concentrations after the first year post-vaccination. When applied to data collected 3.5 years after vaccination of 4-6 year olds with either DTPa or dTpa, …
A robust aerial image registration method using Gaussian mixture models
2014
Aerial image registration is one of the bases in many aerospace applications, such as aerial reconnaissance and aerial mapping. In this paper, we propose a novel aerial image registration algorithm which is based on Gaussian mixture models. First of all, considering the characters of the aerial images, the work uses a shape feature detector which computes the boundaries of regions with nearly the same gray-value to extract invariant feature. Then, a Gaussian mixture models (GMM) based image registration model is built and solved to estimate the transformation matrix between two aerial images. Furthermore, the proposed method is applied on real aerial images, and the results demonstrate the …
Enhanced Role of Transition Metal Ion Catalysis During In-Cloud Oxidation of SO2
2013
Global sulfate production plays a key role in aerosol radiative forcing; more than half of this production occurs in clouds. We found that sulfur dioxide oxidation catalyzed by natural transition metal ions is the dominant in-cloud oxidation pathway. The pathway was observed to occur primarily on coarse mineral dust, so the sulfate produced will have a short lifetime and little direct or indirect climatic effect. Taking this into account will lead to large changes in estimates of the magnitude and spatial distribution of aerosol forcing. Therefore, this oxidation pathway-which is currently included in only one of the 12 major global climate models-will have a significant impact on assessmen…
A new approach for characterizing atmospheric aerosols from spectral values of their optical depth. A simulated case study.
2005
We are developing a new method to determine the spectral contribution to the aerosol optical depth due to each aerosol type. An aerosol type depends directly on the procedence of the particles (marine, continental, artic, etc) and it is formed by some different pure components (mineral, soot, soluble and insoluble particles, sulphate, etc). In order to separate these contributions it is necessary to have the spectral aerosol optical thickness and aerosol size distribution. We use this distribution function to identify the different components of aerosols allowing us to reconstruct the aerosol optical depth taking into account the contribution of each type of aerosol. The validation of the m…
An investigation of the mechanical properties of rubber modified asphalt mixtures using a modified dry process
2017
Incorporating recycling tyres into asphalt mixtures contributes to solving a serious environmental problem as well as the potential of improving the mechanical performance of asphalt mixtures. The recycled tyre rubber is added by two technologies known as the dry process (when rubber particles are treated as an aggregate modifier) and the wet process (when rubber particles are treated as a binder modifier). Although, the dry process is easier and requires minimal or no modification in the asphalt plant, the inconsistency in field performance makes the dry process not widely used. The main reason for this is believed to be the lack of interaction between the rubber particles and binder. In o…
Towards a new mix design method for asphalt mixtures containing rap
2016
Recycling is one of the most important aspects to conceive the new construction or rehabilitation of sustainable road infrastructures. Even if Reclaimed Asphalt Pavement (RAP) is commonly used in the practice, its presence may lead to some critical aspects due to the physical and chemical phenomena occurring during the new mix process. For instance, the formation of RAP clusters during a new mix may inhibit the uniform distribution of the virgin binder as well as cause changes in the design grading curve of the mixture. Indeed, laboratory results demonstrate that small-size RAP particles stick together forming clusters. The amount of clusters depends on different parameters observed: The pe…
Choline is a Selective Agonist of α7 Nicotinic Acetylcholine Receptors in the Rat Brain Neurons
1998
In the present study, we demonstrate that choline, a precursor of acetylcholine (ACh) and a product of acetylcholine hydrolysis by acetylcholinesterase (AChE), acts as an efficient and relatively selective agonist of alpha7-containing nicotinic acetylcholine receptors (nAChR) in neurons cultured from the rat hippocampus, olfactory bulb and thalamus as well as in PC12 cells. Choline was able to activate postsynaptic and presynaptic alpha7 nAChRs, with the latter action resulting in the release of other neurotransmitters. Although choline was approximately one order of magnitude less potent than ACh (EC50 of 1.6 mM for choline and 0.13 mM for ACh), it acted as a full agonist at alpha7 nAChRs.…