Search results for "complex"
showing 10 items of 5889 documents
A cocrystal of two Mo(VI) complexes bearing different diastereomers of the 2,4-di-tert-butyl-6-{[(1-oxido-1-phenylpropan-2-yl)(methyl)amino]methyl}ph…
2013
The title cocrystal contains two chiral conformational diastereomers, viz. (1S,2R,RN)- and (1S,2R,SN)-, of [2,4-ditert-butyl-6-{[(1-oxido-1-phenylpropan-2-yl)(methyl)amino]- methyl}phenolato](methanol)-cis-dioxidomolybdenum(VI), [Mo(C25H35NO2)O2(CH3OH)], representing the first example of a structurally characterized molybdenum complex with enantiomerically pure ephedrine derivative ligands. The MoVI cations exhibit differently distorted octahedral coordination environments, with two oxide ligands positioned cis to each other. The remainder of the coordination comprises phenoxide, alkoxide and methanol O atoms, with an amine N atom completing the octahedron. The distinct complexes are linked…
Impact of humic acids on EYL liposome membranes: ESR method
2015
Abstract In this paper, the effects of model (commercial) and natural (extracted from peat) humic substances on the membrane of liposomes formed with egg yolk lecithin (EYL) are presented. In our research, mass concentrations of fulvic and humic acids were used, which in relation to lecithin varied from 0% to 13%. To study membrane fluidity, electron spin resonance (EPR) was used with two spin probes, penetrating various regions of the lipid bilayer. The effects of model and natural humic substances (humic acids – HAs and fulvic acids – FAs) on the lipid membrane in different regions were researched: the lipid-water interphase, and in the middle of the lipid bilayer. It was shown that FA an…
Microwave-Assisted Esterification of Tall Oil Fatty Acids with Methanol Using Lignin-Based Solid Catalyst
2016
During alkaline pulping significant amounts of lignin, carbohydrates (mostly hemicelluloses), and extractives (tall oil soap and turpentine) are removed from wood feedstock. In this study, the catalytic esterification of fatty acids in tall oil with methanol to produce fatty acid methyl esters under microwave irradiation was performed at 100 °C for 10–60 min. A novel heterogeneous acid catalyst tested for this purpose was synthesized from the hardwood alkali lignin that was precipitated by acidification from the black liquor from soda-AQ pulping. The comparative reaction data were obtained by using other solid catalysts, Amberlyst 15, and p-toluenesulfonic acid. The results showed the highe…
Aging of the musculoskeletal system: How the loss of estrogen impacts muscle strength.
2019
Skeletal muscle weakness occurs with aging and in females this is compounded by the loss of estrogen with ovarian failure. Estrogen deficiency mediates decrements in muscle strength from both inadequate preservation of skeletal muscle mass and decrements in the quality of the remaining skeletal muscle. Processes and components of skeletal muscle that are affected by estrogens are beginning to be identified. This review focuses on mechanisms that contribute to the loss of muscle force generation when estrogen is low in females, and conversely the maintenance of strength by estrogen. Evidence is accumulating that estrogen deficiency induces apoptosis in skeletal muscle contributing to loss of…
La storia celata del trauma complesso. Una rassegna teorica tra realtà clinica e problemi diagnostici
2017
Il presente contributo si propone di analizzare le difficoltà di riconoscimento e legittimazione, storicamente presenti nello studio del trauma psichico infantile, nonché di stimolare riflessioni aperte sulla possibilità che tali difficoltà siano ancora attuali. Recenti contributi sullo studio del disturbo traumatico dello sviluppo sottolineano infatti l’importanza degli aspetti relazionali e cumulativi nonché del momento evolutivo in cui il soggetto vive le proprie esperienze traumatiche.
Evolutionary Dynamics of Inter-firm Networks: A Complex Systems Perspective
2008
This chapter aims to identify the main determinants that define the architectural properties of network emergence and significantly influence the dynamics underlying network evolution in time. The identification and analysis of these determinants, as well as the dynamic processes tied to them, allows to appreciate the competitive bases and consequences of network morphology. To this purpose, using a complex systems perspective as an integrative conceptual approach, we represent networks as complex dynamic systems of knowledge and capabilities. We perform a comparative in-depth analysis of the processes underlying the emergence and evolution of STMicroelectronic's global network and of Toyot…
Fonds de retraite et performance : la famille compte-t-elle ?
2008
(VF)Actuellement, la majorité des fonds mutuels ou des fonds de pension appartient à une famille. Une famille comprend les fonds gérés par la même société. Cet article s’intéresse à la performance des fonds de pension anglais à cotisations définies sur longue période. La performance est mesurée du point de vue de la famille de fonds. Ce changement de niveau d’analyse amène à s’interroger sur l’influence de la taille et donc de la complexité organisationnelle des sociétés de gestion de portefeuille sur leur performance. Autrement dit, les petites familles présentent-elles des performances supérieures à celles des grandes familles? (VA)Almost all mutual funds or pension funds belong to a fami…
Oxidovanadium(v) complexes with l-proline-based amino acid phenolates
2019
Abstract l -proline was used to prepare chiral, tridentate amino acid phenol proligands H2L1–4. These proligands react with vanadium precursors VO(acac)2, VOSO4∙5H2O and VO(OPr)3 in methanol to form the corresponding oxidoalkoxidovanadium( v ) complexes 1–4. The complexes crystallize from methanol, and are octahedrally coordinated with a general formula [VO(L1–4)(OMe)(MeOH)]. In solution, however, they adopt several different conformations or isomeric structures depending on the solvent.
Bi-, Tetra-, and Hexanuclear AuI and Binuclear AgI Complexes and AgI Coordination Polymers Containing Phenylaminobis(phosphonite), PhN{P(OC6H4OMe-o)2…
2008
The reactions of phenylaminobis(phosphonite), PhN{P(OC6H4OMe-o)2}2 (1) (PNP), with [AuCl(SMe2)] in appropriate ratios, afford the bi- and mononuclear complexes, [(AuCl)2(µ-PNP)] (2) and [(AuCl)(PNP)]2 (3) in good yield. Treatment of 2 with 2 equiv of AgX (X = OTf or ClO4) followed by the addition of 1 or 2,2′-bipyridine affords [Au2(µ-PNP)2](OTf)2 (4) and [Au2(C10H8N2)2(µ-PNP)](ClO4)2 (5), respectively. Similarly, the macrocycles [Au4(C4H4N2)2(µ-PNP)2](ClO4)4 (6), [Au4(C10H8N2)2(µ-PNP)2](ClO4)4 (7), and [Au6(C3H3N3)2(µ-PNP)3](ClO4)6 (8) are obtained by treating 2 with pyrazine, 4,4′-bipyridine, or 1,3,5-triazine in the presence of AgClO4. The reaction of 1 with AgOTf in a 1:2 molar ratio pr…
The average state complexity of rational operations on finite languages is linear
2010
Considering the uniform distribution on sets of m non-empty words whose sum of lengths is n, we establish that the average state complexities of the rational operations are asymptotically linear.