Search results for "M2"
showing 10 items of 256 documents
Prediction of phase transformation of Ti-6Al-4V titanium alloy during hot-forging processes using a numerical model
2013
In this article numerical model for prediction of phase evolution of Ti-6Al-4V titanium alloy was presented. In particular, attention was focused on alpha to beta and beta to alpha+beta phase transformations. The analysis was conducted using a commercial implicit finite element method code, considering the data and the parameters of a real case study to check the quality of the numerical model. The alpha to beta transformation was developed using the simplified form of the Avrami model and the beta to alpha+beta transformation was controlled through the generalized Avrami model. The model so-thought has been used to conduct a 2D simulation of a forging process. A comparison between the num…
Blown-up toric surfaces with non-polyhedral effective cone
2020
We construct examples of projective toric surfaces whose blow-up at a general point has a non-polyhedral pseudo-effective cone, both in characteristic $0$ and in every prime characteristic $p$. As a consequence, we prove that the pseudo-effective cone of the Grothendieck-Knudsen moduli space $\overline M_{0,n}$ of stable rational curves is not polyhedral for $n\geq 10$ in characteristic $0$ and in characteristic $p$, for all primes $p$. Many of these toric surfaces are related to a very interesting class of arithmetic threefolds that we call arithmetic elliptic pairs of infinite order. Their analysis in characteristic $p$ relies on tools of arithmetic geometry and Galois representations in …
Conformal invariance of the writhe of a knot
2008
We give a new proof of an old theorem by Banchoff and White 1975 that claims that the writhe of a knot is conformally invariant.
Generalized Dehn twists in low-dimensional topology
2021
The generalized Dehn twist along a closed curve in an oriented surface is an algebraic construction which involves intersections of loops in the surface. It is defined as an automorphism of the Malcev completion of the fundamental group of the surface. As the name suggests, for the case where the curve has no self-intersection, it is induced from the usual Dehn twist along the curve. In this expository article, after explaining their definition, we review several results about generalized Dehn twists such as their realizability as diffeomorphisms of the surface, their diagrammatic description in terms of decorated trees and the Hopf-algebraic framework underlying their construction. Going t…
Blow-up of the non-equivariant 2+1 dimensional wave map
2014
It has been known for a long time that the equivariant 2+1 wave map into the 2-sphere blows up if the initial data are chosen appropriately. Here, we present numerical evidence for the stability of the blow-up phenomenon under explicit violations of equivariance.
The use of low-resolution phasing followed by phase extension from 7.6 to 2.5 Å resolution with noncrystallographic symmetry to solve the structure o…
2011
P2, the major capsid protein of bacteriophage PM2, adopts the double β-barrel fold characteristic of the PRD1-adenoviral lineage. The 2.5 Å resolution X-ray data obtained by analysis of the two major lattices of a multiple crystal of P2 were phased by molecular replacement, using as a search model structure factors to 7.6 Å resolution obtained from electron density cut from the map of the entire PM2 virion. Phase extension to 2.5 Å resolution used solely sixfold cycling averaging and solvent flattening. This represents an atypical example of an oligomeric protein for which the structure has been determined at high resolution by bootstrapping from low-resolution initial phases.
On base loci of higher fundamental forms of toric varieties
2019
We study the base locus of the higher fundamental forms of a projective toric variety $X$ at a general point. More precisely we consider the closure $X$ of the image of a map $({\mathbb C}^*)^k\to {\mathbb P}^n$, sending $t$ to the vector of Laurent monomials with exponents $p_0,\dots,p_n\in {\mathbb Z}^k$. We prove that the $m$-th fundamental form of such an $X$ at a general point has non empty base locus if and only if the points $p_i$ lie on a suitable degree-$m$ affine hypersurface. We then restrict to the case in which the points $p_i$ are all the lattice points of a lattice polytope and we give some applications of the above result. In particular we provide a classification for the se…
Muscarinic modulation of acetylcholine release: Receptor subtypes and possible mechanisms
1989
The release of acetylcholine from central and peripheral neurones can be inhibited and facilitated by muscarine autoreceptors, i.e. receptors located on the cholinergic neurone. In the last few years evidence has accumulated that muscarine receptors are heterogeneous. This chapter describes attempts that have been made to classify the muscarine autoreceptors. In addition, some possible mechanisms behind the neuronal muscarine receptors are examined.
Activation of Muscarinic Receptors by Non-neuronal Acetylcholine
2011
The biological role of acetylcholine and the cholinergic system is revisited based particularly on scientific research early and late in the last century. On the one hand, acetylcholine represents the classical neurotransmitter, whereas on the other hand, acetylcholine and the pivotal components of the cholinergic system (high-affinity choline uptake, choline acetyltransferase and its end product acetylcholine, muscarinic and nicotinic receptors and esterase) are expressed by more or less all mammalian cells, i.e. by the majority of cells not innervated by neurons at all. Moreover, it has been demonstrated that acetylcholine and “cholinergic receptors” are expressed in non-neuronal organism…
Behavioural and pharmacological characterization of a novel cannabinomimetic adamantane-derived indole, APICA, and considerations on the possible mis…
2015
The novel adamantane derivative APICA (N-(adamantan-1-yl)-1-pentyl-1H-indole-3-carboxamide) was recently identified as a cannabinomimetic indole of abuse. Despite its novel structure, APICA recalls cannabinomimetic indoles, such as representative member JWH-018.In present study, the effects of APICA (1-3 mg/kg, i.p.) were tested in C57BL/6J mice, in the Tetrad task which includes the assessment of: body temperature; locomotor activity and behavioural reactivity; nociception; motor coordination; declarative memory. Furthermore, pre-treatment with the CB1 antagonist AM251 (3 mg/kg, i.p.) or the CB2 antagonist AM630 (3 mg/kg, i.p.) was carried out to characterize APICA activity.Our results sho…