Search results for "Tact"
showing 10 items of 1313 documents
Effects of Natural Products on Contact Dermatitis
2005
Some medicinal plants, which are known to produce allergic reactions, are also specifically used as anti- inflammatory agents. Among the more relevant plants, we report species with cinnamaldehyde, cinnamic alcohol, geraniol, hydroxycitronellal, eugenol and isoeugenol are all potential allergens. In addition, fragrances, which are mixtures of small-molecul ar-weight compounds, may induce allergic contact dermatitis due to fragrance-spe cific CD4 + and CD8 + T lymphocytes. Plants from the Asteraceae family used in folk medicine as anti-inflamma tories can cause allergic contact dermatitis because of its content in sesquiterpene lactones, which have been reported as the anti- inflammatory pri…
2,3,7,8-Tetrachlorodibenzo-p-dioxin-Dependent Release from Contact Inhibition in WB-F344 Cells: Involvement of Cyclin A
2002
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most potent tumor promoter ever tested in rodents. Although it is known that most of TCDD actions are mediated by binding to the aryl hydrocarbon receptor (AhR), the mechanisms leading to tumor promotion still remain to be elucidated. Loss of contact inhibition is one characteristic hallmark in tumorigenesis. In rat liver epithelial WB-F344 cells, TCDD induces a release from contact inhibition, which is manifested by a twofold increase in cell number when TCDD (1 nM for 48 h) is added to confluent cells in the presence of serum, but not when given to exponentially growing or subconfluent, serum-deprived WB-F344 cells. Loss of G1 arrest was a…
Rewarding Properties of Testosterone in Intact Male Mice
2000
The present study examined the rewarding properties of 4-androsten-17β-ol-3-one testosterone in intact male mice using the conditioned place preference (CPP) technique. In Experiment 1, the pharmacokinetics of 0.8 and 1.2 mg/kg of testosterone were studied to determine the most appropriate temporal interval to test behavior. Additionally, the locomotor activity was recorded to control a possible interfering effect on CPP. The maximum testosterone concentration was registered at 45 min of administration, and no effects on activity were found. In Experiment 2, three groups of male OF-1 mice received four pairings of the least-preferred compartment with testosterone (0.8, 1, or 1.2 mg/kg, SC) …
Two-state protein-like folding of a homopolymer chain
2010
Many small proteins fold via a first-order "all-or-none" transition directly from an expanded coil to a compact native state. Here we study an analogous direct freezing transition from an expanded coil to a compact crystallite for a simple flexible homopolymer. Wang-Landau sampling is used to construct the 1D density of states for square-well chains of length 128. Analysis within both the micro-canonical and canonical ensembles shows that, for a chain with sufficiently short-range interactions, the usual polymer collapse transition is preempted by a direct freezing or "folding" transition. A 2D free-energy landscape, built via subsequent multi-canonical sampling, reveals a dominant folding …
Phase Transitions in Prequenched Mesomorphic Isotactic Polypropylene during Heating and Annealing Processes As Revealed by Simultaneous Synchrotron S…
2011
Time-resolved simultaneous synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) technique was used to investigate the phase transitions in prequenched mesomorphic isotactic polypropylene (iPP) samples during heating and annealing processes, respectively. For the heating process, it is shown that the mesomorphic-to-monoclinic phase transition is relatively faster for the mesomorphic iPP sample obtained with the high quenching rate than that with the low quenching rate. For the former, the stability of α-monoclinic crystals formed during heating is relatively higher. As for the annealing process, WAXD and SAXS data illustrate that the higher the annealing te…
Early signs of dyslexia from the speech and language processing of children
2009
The Jyvaskyla Longitudinal Study of Dyslexia project (JLD) has followed the development of 200 children from birth until 10 years of age. Half the children are from families in which at least one of the parents has dyslexia, thus the child has a high risk of becoming dyslexic, and half have no such risk. Here the main findings of four studies in linguistics from the JLD project are reviewed. The speech processing skills were studied in 6, 18, 24 and 30-month-old children. The findings show that early signs of dyslexia can be detected in speech processing both phonologically and morphosyntactically. These precursors can be seen in perception or production of duration, in the prosody and phon…
Subsurface treatment of a contact subjected to a hertz pressure
2013
Abstract The study proposes an approach allowing the favorable modification of the stresses field of a structure subjected to a Hertzian contact. It is based on the study of a classic Hertzian contact in the presence of subsurface circular defects. The idea is to limit the field of tangential stresses without large increasing of the global stress (Von Mises) of the system. The location of the defects is made according to the mechanical parameters of the contact (Fn, has, z). The results of the numerical calculations (FEM) are compared with photoelastic measurements and highlight an excellent correlation. The location of the defect on the symmetry axis (x=0) is the dominating parameter for t…
Effects of Oxygen Plasma on the Chemical, Light-Emitting, and Electrical-Transport Properties of Inorganic and Hybrid Lead Bromide Perovskite Nanocry…
2018
We show that oxygen plasma affects in different ways the structural, chemical, optical, and electrical properties of methylammonium and cesium lead bromide nanocrystals. Hybrid organic–inorganic nanocrystals were severely and quickly degraded by oxygen plasma at 50 W. Their photoluminescence was quenched with almost 100% loss of the initial quantum yield, which is linked to decomposition of the nanocrystals. Inorganic nanocrystals were more resistant to oxygen plasma in the same conditions. Despite a moderate loss of photoluminescence and electrical conductivity, oxygen plasma had a positive impact, removing unbound ligands and resulting in more ohmic behavior of the film. This paves the wa…
Four colour photometry of late-type binary systems
1997
This paper presents rst complete uvby light curves of the late-type detached eclipsing binary ZZ UMa (G0V + G8V, P =2 : d 2993). This binary system has been observed during eight campaigns at the Calar Alto Observatory (Almeria, Spain)and at the Sierra Nevada Observatory (Granada, Spain). 294 points distributed over the binary period and covering both eclipses are given. The comparison stars used to calculate the dierential light curves (SAO 15242 and SAO 15251) were conrmed as being good reference stars with constant flux. These observations are part of a 6 year uvby and H monitor- ing program of low mass eclipsing binaries whose main objective is to provide accurate absolute astrophysical…
Effect of quantized conductivity on the anomalous photon emission radiated from atomic-size point contacts
2019
We observe anomalous visible to near-infrared electromagnetic radiation emitted from electrically driven atomic-size point contacts. We show that the number of photons released strongly depends on the quantized conductance steps of the contact. Counter-intuitively, the light intensity features an exponential decay dependence with the injected electrical power. We propose an analytical model for the light emission considering an out-of-equilibrium electron distribution. We treat photon emission as bremsstrahlung process resulting from hot electrons colliding with the metal boundary and a find qualitative accord with the experimental data.