Search results for " Phase"
showing 10 items of 1862 documents
Key-ring structure gradients and sheath folds in the Goantagab Domain of NW Namibia
2011
Abstract The concept of deformation phases is one of the corner stones of structural geology but, despite its simplicity, there are situations where the concept breaks down. In the Goantagab Domain of NW Namibia, structures in an area of complex deformation can be subdivided into at least four sets, attributed to four deformation phases on the basis of overprinting relations. Three of these sets of structures, however, formed during the same tectonic event under similar metamorphic circumstances but slightly different flow conditions. These sets of structures show gradational transitions in space that can be understood by a concept of “key-ring structure gradients”, where older D A structur…
Dynamic regulation of CD8 T cell tolerance induction by liver sinusoidal endothelial cells.
2010
Abstract Cross-presentation of soluble Ag on MHC class I molecules to naive CD8 T cells by liver sinusoidal endothelial cells (LSECs) leads to induction of T cell tolerance that requires interaction between coinhibitory B7-H1 on LSECs and programmed cell death-1 on CD8 T cells. In this study, we investigate whether cross-presentation of high as well as low Ag concentrations allowed for LSEC-induced tolerance. Ag concentration directly correlated with the cross-presentation capacity of murine LSECs and thus strength of TCR stimulation. Although LSEC cross-presentation at low-Ag concentrations resulted in tolerance, they induced differentiation into effector T cells (CTL) at high-Ag concentra…
Acute stress may induce ovulation in women
2010
Abstract Background This study aims to gather information either supporting or rejecting the hypothesis that acute stress may induce ovulation in women. The formulation of this hypothesis is based on 2 facts: 1) estrogen-primed postmenopausal or ovariectomized women display an adrenal-progesterone-induced ovulatory-like luteinizing hormone (LH) surge in response to exogenous adrenocorticotropic hormone (ACTH) administration; and 2) women display multiple follicular waves during an interovulatory interval, and likely during pregnancy and lactation. Thus, acute stress may induce ovulation in women displaying appropriate serum levels of estradiol and one or more follicles large enough to respo…
Unpredicted ovulations and conceptions during early pregnancy: an explanatory mechanism of human superfetation
2012
In this bioessay, a literature review on human superfetation was performed in order to find epidemiological variables associated with this phenomenon. Thereafter, an explanatory mechanism of superfetation compatible with the endocrinological, histological and physiological changes undergone by women during early pregnancy is proposed. Superfetation can be defined as the ovulation, fertilisation and implantation of a second or additional embryo(s) during pregnancy. The literature review evidences a small discordance in gestational age between dizygotic twins in humans (range: 2–4 weeks; mean ± s.e.m.: 3.3 ± 0.3 weeks). This difference is compatible with a luteal out-of-phase (LOOP; i.e. atyp…
MCC1019, a selective inhibitor of the Polo-box domain of Polo-like kinase 1 as novel, potent anticancer candidate
2019
Polo-like kinase (PLK1) has been identified as a potential target for cancer treatment. Although a number of small molecules have been investigated as PLK1 inhibitors, many of which showed limited selectivity. PLK1 harbors a regulatory domain, the Polo box domain (PBD), which has a key regulatory function for kinase activity and substrate recognition. We report on 3-bromomethyl-benzofuran-2-carboxylic acid ethyl ester (designated: MCC1019) as selective PLK1 inhibitor targeting PLK1 PBD. Cytotoxicity and fluorescence polarization-based screening were applied to a library of 1162 drug-like compounds to identify potential inhibitors of PLK1 PBD. The activity of compound MC1019 against the PLK1…
Stability and nature of the volume collapse of ε-Fe2O3 under extreme conditions
2018
Iron oxides are among the major constituents of the deep Earth’s interior. Among them, the epsilon phase of Fe2O3 is one of the less studied polymorphs and there is a lack of information about its structural, electronic and magnetic transformations at extreme conditions. Here we report the precise determination of its equation of state and a deep analysis of the evolution of the polyhedral units under compression, thanks to the agreement between our experiments and ab-initio simulations. Our results indicate that this material, with remarkable magnetic properties, is stable at pressures up to 27 GPa. Above 27 GPa, a volume collapse has been observed and ascribed to a change of the local env…
Fully automatic simultaneous fiber grating amplitude and group delay characterization
1997
Electrically tunable photonic true-time-delay line
2010
We present a new application of the acousto-optic superlattice modulation of a fiber Bragg grating based on the dynamic phase and group delay properties of this fiber-optic component. We demonstrate a tunable photonic true-time-delay line based on the group delay change of the light reflected from the grating sidebands. The delay is electrically tuned by adjusting the voltage applied to a piezoelectric transducer that generates the acoustic wave propagating along the grating. In our experiments, a true-time delay of 400 ps is continuously adjusted (300 ps within the 3 dB amplitude range of the first sideband), using a 12 cm long uniform grating.
A molecular approach to remove lead from drinking water
2005
Abstract Corrosion of lead-containing plumbings is responsible for significant contamination of tap water, which can reach several hundreds of micrograms per liter. According to a decision of the European Council applicable in 2013, the maximal lead level in tap water should not exceed 10 μg l −1 . A new concept has been explored that relies on solid-phase extraction by covalent attachment of a lead-selective macrocyclic sequestering agent onto the surface of silica gel. An N -carbamoylmethyl substituted 1,4,8,11-tetraazacyclotetradecane (cyclam) derivative was shown to exhibit favorable protonation properties together with an almost 10 6 -fold selectivity for lead over calcium. Structural …