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showing 10 items of 38174 documents
Senso e prospettive di un incontro
2020
Nella postfazione si evidenzia l'importanza di valorizzare le collezioni universitarie sia per i loro numerosi elementi di interesse, sia per gli input che forniscono per ulteriori iniziative e progressi di conoscenza, secondo le parole d'ordine di "fare rete" e "sistematizzare" i vari asset, specializzazioni, conoscenza e utenti In the afterword the importance of enhancing university collections is highlighted both for their numerous elements of interest, and for the inputs they provide for further initiatives and knowledge progress, according to the watchwords of "networking" and "systematizing" the various assets , specialisms, knowledge and users
Una memoria fragile? Collezioni di calchi in gesso e il loro ruolo di eredità storica tra passato e presente
2020
A collection of papers about the recovery and the new arrangement of the plaster casts of ancient sculpture at the University of Palermo in Italy and the University of Leipzig in Germany
Plasma PAF-acetylhydrolase in patients with coronary artery disease: results of a cross-sectional analysis.
2003
Inflammation underlies both onset and perpetuation of atherosclerosis. Plasma lipoproteins transport the platelet-activating factor-acetylhydrolase (PAF-AH) with potentially anti-inflammatory activities. Our aim was to determine whether PAF-AH activity was associated with inflammatory markers and with coronary artery disease (CAD). PAF-AH activity and a panel of inflammatory mediators were measured in plasma of 496 patients with CAD and in 477 controls; 276 patients presented with stable angina pectoris and 220 with acute coronary syndrome (ACS). Individuals within the highest quartile of PAF-AH activity had an 1.8-fold increase in CAD risk [95% confidence interval (CI), 1.01 to 3.2; P = 0.…
Self-Consistent Charge Density-Functional Tight-Binding Parametrization for Pt–Ru Alloys
2017
We present a self-consistent charge density-functional tight-binding (SCC-DFTB) parametrization for PtRu alloys, which is developed by employing a training set of alloy cluster energies and forces obtained from Kohn-Sham density-functional theory (DFT) calculations. Extensive simulations of a testing set of PtRu alloy nanoclusters show that this SCC-DFTB scheme is capable of capturing cluster formation energies with high accuracy relative to DFT calculations. The new SCC-DFTB parametrization is employed within a genetic algorithm to search for global minima of PtRu clusters in the range of 13-81 atoms and the emergence of Ru-core/Pt-shell structures at intermediate alloy compositions, consi…
Self-healing, luminescent metallogelation driven by synergistic metallophilic and fluorine–fluorine interactions
2020
Square planar platinum(ii) complexes are attractive building blocks for multifunctional soft materials due to their unique optoelectronic properties. However, for soft materials derived from synthetically simple discrete metal complexes, achieving a combination of optical properties, thermoresponsiveness and excellent mechanical properties is a major challenge. Here, we report the rapid self-recovery of luminescent metallogels derived from platinum(ii) complexes of perfluoroalkyl and alkyl derivatives of terpyridine ligands. Using single crystal X-ray diffraction studies, we show that the presence of synergistic platinum-platinum (PtMIDLINE HORIZONTAL ELLIPSISPt) metallopolymerization and f…
PtII versus PdII-assisted [2+3] cycloadditions of nitriles and nitrone. Synthesis of nitrile-derived arylamido platinum(II) and Δ4-1,2,4-oxadiazoline…
2019
Abstract The reactions of bis(organonitrile) platinum(II) complexes trans-[PtCl2(N CR)2] (R = C6H4(p-HC O), CH2C6H4(p-CH3)) with pyrroline N-oxide −O+N CHCH2CH2CMe2 afford arylamido platinum(II) complexes trans-[PtCl2{(O CR)N CCH2CH2CMe2NH}2] (R = C6H4(p-HC O) (1), CH2C6H4(p-CH3) (2)). The spectral data of 1 and 2 show that the oxadiazoline rings in both cases have opened by a spontaneous N O bond cleavage to form (Z)-p-formyl-N-(5,5-dimethylpyrrolidin-2-ylidene)benzamide or (Z)-N-(5,5-dimethylpyrrolidin-2-ylidene)-2-p-tolylacetamide ligands, respectively, where the N-atoms of the benzamide or acetamide moieties coordinate to platinum(II) metal centre in trans positions. However, the reacti…
Bis(hydroxyammonium) hexachloridoplatinate(IV)–18-crown-6 (1/2)
2014
In the title complex, (NH3OH)2[PtCl6]·2C12H24O6, the PtIV atom is coordinated by six chloride anions in a slightly distorted octahedral geometry. The Pt—Cl bond lengths are comparable to those reported for other hexachloridoplatinate(IV) species. The hydroxyammonium groups act as linkers between the [PtCl6]2− anion and the crown ether molecules. The anion is linked to two hydroxyammonium cations via O—H...Cl hydrogen bonds and each hydroxyammonium moiety is linked to a crown ether molecule by hydrogen bonds between ammonium H atoms and 18-crown-6 O atoms. The crown ether molecules have the classic crown shape in which all O atoms are located in the inner part of the crown ether ring and all…
Noncovalent axial I∙∙∙Pt∙∙∙I interactions in platinum(II) complexes strengthen in the excited state
2021
Abstract Coordination compounds of platinum(II) participate in various noncovalent axial interactions involving metal center. Weakly bound axial ligands can be electrophilic or nucleophilic; however, interactions with nucleophiles are compromised by electron density clashing. Consequently, simultaneous axial interaction of platinum(II) with two nucleophilic ligands is almost unprecedented. Herein, we report structural and computational study of a platinum(II) complex possessing such intramolecular noncovalent I⋅⋅⋅Pt⋅⋅⋅I interactions. Structural analysis indicates that the two iodine atoms approach the platinum(II) center in a “side‐on” fashion and act as nucleophilic ligands. According to c…
Okręty podwodne typu Vanguard jako podstawa brytyjskiego systemu odstraszania militarnego w XXI wieku
2016
W świecie pozimnowojennym arsenał atomowy bogatych państw Zachodu przestał odgrywać decydującą rolę w polityce międzynarodowej. Nie znaczy to jednak, iż państwa te całkowicie zrezygnowały z tego narzędzia wywierania wpływu i wyznacznika pozycji siły. Broń atomowa w XXI w. nadal pozostaje najbardziej śmiercionośnym narzędziem pozostającym w arsenale wojskowym. W związku z tym każde państwo dysponujące tego typu uzbrojeniem poszukuje co rusz nowych metod i środków przenoszenia, użycia i modernizacji tejże. W przypadku Wielkiej Brytanii sytuacja jest szczególna, ponieważ flota strategicznych okrętów podwodnych o napędzie atomowym typu Vanguard jest jedynym brytyjskim rodzajem uzbrojenia zdolny…
Mind the gap: Treefalls as drivers of parental trade-offs
2015
Abstract Tree‐fall gaps are small‐scale disturbances whose formation, colonization, and role in forest dynamics are well documented, but whose effects on animal ecology are still greatly overlooked, except for studies comparing species richness of gaps 6+ months old to that in the closed canopy. Other factors associated with the invasion of fresh tree‐fall gaps such as animal breeding adaptations have been largely neglected. I studied the immediate (within hours and days) arrival of the poison frog Dendrobates tinctorius in new tree‐fall gaps to examine the dynamics of their invasion in relation to tadpole rearing. I found that rearing sites are occupied sooner and tadpoles deposited at hig…