Search results for "opening"

Molte Palermo. Temi

2019

Nel tema delle incompiute idee di città possibili si riconoscerà il paradigma connotativo dello stesso divenire di Palermo, lungo un percorso millenario di processi di trasformazione nessuno dei quali portato a compimento, in virtù di quel valore distintivo di exemplum che non necessita di ulteriori e conclusive dimostrazioni. Il corso della storia, del resto, ha imposto a Palermo il ciclico riproporsi di destini interrotti. Tale si rilevò l’invenzione della città capitale, quella della “quadratura geometrica e della croce di strade” sovrimpressa a quella archetipica e fondativa della Pan-ormos scambiatrice. E l’incompiutezza sarà il tratto distintivo della città dei rettifili stradali otto…

From Benzofurans to Indoles: Palladium-Catalyzed Reductive Ring-Opening and Closure via β-Phenoxide Elimination

2018

International audience; Benzofurans can undergo ring-opening by a palladium-catalyzed process resulting in C−O bond breaking. Benzofuran-tethered 2-iodoanilines give synthetically interesting 2-(3-indolylmethyl)phenols in an overall reductive process. Mechanistic studies suggest that this unusual reaction proceeds by carbopalladation of benzofuran giving a 3-palladated 2,3-dihydrobenzofuran intermediate, which then fragments by an uncommon trans-elimination of the phenoxide group β to the metal. In this transformation, N,N-diisopropylethylamine (DIPEA) acts as a base and as a reducing agent: it regenerates palladium(0) from palladium(II), thus allowing catalytic turnover.

Chiroptical Induction and Molecular Recognition in Optically Active Hyperbranched Polyethers with Inherently Chiral Benzophenone Core

2010

Fatigue Design of Cruciform Joints including V-notch Effect at the Weld Toe

2014

Abstract The present paper proposes a new and more accurate fatigue life prediction model for fillet welded joints in steel subjected to constant amplitude loading. With the traditional fracture mechanics approach, the greatest difficulty when computing the fatigue life of a welded detail is to determine the initial crack size a0. The classical way to determine the stress intensity factor K (SIF) is by using the following formula Where σ is the applied stress, a is the crack size and g(a/T) the geometrical correction factor which has been determined by Gurney function or similar solutions. This approach is not accurate for short crack because of the singular V-notch behaviour close to the c…

Poly(isoglycerol methacrylate)-b-poly(d or l-lactide) Copolymers: A Novel Hydrophilic Methacrylate as Building Block for Supramolecular Aggregates

2010

On the basis of a new acetal-protected glycerol monomethacrylate monomer (cis-1,3-benzylidene glycerol methacrylate/BGMA) a series of potentially biocompatible and partially biodegradable homo- and block copolymers were synthesized. ATRP polymerization of BGMA yielded well-defined polyacrylates with pendant benzylidene acetal groups and high glass transition temperatures (115−130 °C). This hydrophobic poly(cis-1,3-benzylidene glycerol methacrylate) could be readily transformed into the hydrophilic and water-soluble poly(1,3-dihydroxypropyl methacrylate), referred to as poly(isoglycerol methacrylate) (PIGMA). It exclusively contains primary hydroxyl groups and therefore differs significantly…

Multi-Arm Star Poly(L-lactide) with Hyperbranched Polyglycerol Core

2007

Biocompatible multi-arm star block copolymers based on poly(L-lactide) (PLLA) have been prepared by a core-first approach, using hyperbranched polyglycerol (PG), a polyether polyol, as a polyfunctional initiator. The molecular weight of the hyperbranched initiator-core was varied from 2 200 to 5 200 g mol -1 , molecular weights of the resulting multi-arm stars were in the range of 6 700-107 000 g mol -1 (NMR), depending on the amount of dilactide (LA) added. Various monomer/initiator ratios have been employed in the Sn-catalyzed LA polymerization in order to vary the length of the lactide arms from DP n (arm) = 2 to 20 units. Detailed NMR analysis using conventional and 2D-NMR techniques (e…

Homoleptic Phosphoraneiminato Complexes of Rare Earth Elements as Initiators for Ring-Opening Polymerization of Lactones.

2000

Dealing with missing participants in the opening phases of a videoconference

2023

Abstract The paper explores the social interaction that takes place during the initial phases of videoconferences. The focus is on the problem of absent participants, which is often considered a reason for delaying the official beginning of the meeting. One of the resources that the participants have is to reach the absent participant by cellphone. We observed a recurrent pattern of action whereby one of the participants disengages from the video meeting to reach the missing person by phone. This negotiation process moves through four steps: (1) the detection of the problem, (2) the offer to call the missing person by one participant, (3) the acceptance of this offer by the moderator, and (…

Noncovalent Targeting of Nanocarriers to Immune Cells with Polyphosphoester‐Based Surfactants in Human Blood Plasma

2019

Abstract Dendritic cells (DCs) are part of the immune system and can internalize pathogens by carbohydrate receptors. The uptake induces maturation and migration of the DCs resulting in an adaptive immune response by presenting antigens to T‐cells. Thus, targeted delivery to DCs is a powerful tool for immunotherapy. However, in blood, specific targeting is challenging as blood proteins adsorb to the nanocarriers and mask the targeting molecules. Additionally, covalent coupling of targeting groups to nanocarriers requires new chemistry for each nanocarrier, while a general strategy is missing. A general protocol by noncovalent adsorption of mannosylated polyphosphoesters (PPEs) on the nanoca…

Evolución histórica de la autonomía de la voluntad en el Derecho matrimonial

2021

The autonomy of the will or power of self-regulation of relationships derived from marriage is a subject that is on the rise and that we can qualify as novel. More and more couples are opting to proceed making use of this power to self-regulate both personal and property effects derived from their union or its future breakdown. In the Spanish legal system there is no precise and complete regulation of the subject, without all these figures being equally legislated, although all are admitted without any doubt by jurisprudence. In recent years there has been an evolution of Family law, traditionally very reluctant to give space to self-regulation. Our Constitution marks a turning point by cha…