103,488 research outputs found
Ionic Self Assembly in the Design of Fluorinated Ionic Liquid Crystals (ILCs)
No full textIonic liquid crystals are a class of compounds containing anions and cations, that combine the properties of liquid crystals and ionic liquids[1].
In the conventional design of ionic liquid crystalline compounds, an ionic core is connected with mesogenic groups via chemical covalent bonding . Alternatively, in ionic compounds, strong electrostatic interactions between cation and anion can be used to build up liquid crystalline order at supramolecular level. This general approach, called ionic self-assembly (ISA), allows one to create ionic phases and mesophases with highly organized supramolecular order [2].
In this context, a new series of fluorinated ionic liquids (ILs) and ionic liquid crystals (ILCs) was obtained starting from perfluoro-alkylated carboxylic acids and 1,2,4-oxadiazolyl-pyridine units (Figure 1). Their thermotropic properties were investigated by combined differential scanning calorimetry and polarized optical microscopy.
Figure 1.
[1] K.V. Axenov and S. Laschat, Materials, 4, 2011, 206; F. Lo Celso, I. Pibiri, A. Triolo, R. Triolo, A. Pace, S. Buscemi and N. Vivona, J. Mater. Chem., 17, 2007, 1201; V. Causin and G. Saielli, J. Mater. Chem., 19, 2009, 9153.
[2] C.F.J. Faul and M. Antonietti, Adv. Mater., 15, 2003, 673
High-Level Petri Nets as Type Theories in the Join Calculus
No full textWe study the expressiveness of the join calculus by comparison with (generalised, coloured) Petri nets and using tools from type theory. More precisely, we consider four classes of nets of increasing expressiveness, , introduce a hierarchy of type systems of decreasing strictness, , , and we prove that a join process is typeable according to if and only if it is (strictly equivalent to) a net of class . In the details, and contain, resp., usual place/transition and coloured Petri nets, while and propose two natural notions of high-level net accounting for dynamic reconfiguration and process creation and called reconfigurable and dynamic Petri nets, respectively
La felicità pubblica in Sicilia nella modernità tra filosofia e politica
No full textIl saggio documenta la discussione sulla natura pubblica della felicità nel contesto mediterraneo moderno, mettendo in risalto le significative specificità letterarie e ideologiche rispetto al giudizio sull’origine e la legittimità del potere che si possono cogliere in Sicilia
Regulation of the Cell Cycle, Cell Cycle Checkpoints and Cancer
No full textDNA damage response (DDR) pathways are triggered to ensure proper repair of DNA lesions and preserve genome integrity. Key intracellular transducers of the DNA damage are ataxia-telangiectasia mutated kinase (ATM) and ataxia-telangiectasia and Rad3-related kinase (ATR). These nuclear proteins, through dynamic interaction with chromatin-bound sensory components and phosphorylation at T/SQ residues of a multitude of substrates, including the checkpoint kinases Chk1 and Chk2, activate a network of pathways important for DNA repair, multiple cell cycle–phase arrest, transcription, and apoptosis. Interestingly, the DDR machinery is a key mediator of telomere-dependent and telomere-independent forms of cellular senescence, and provides a barrier to aberrant DNA replication induced by oncogenic stimuli. These findings and the constitutive activation of the DDR in human precancerous lesions, underscore the role of the DDR as a tumour suppressor constraining transformation by driving incipient tumour cells into apoptosis or senescence. Since genetic abnormalities of the DDR hypersensitize to genotoxic anticancer agents, this pathway represents a relevant target to increase tumour cell kill and possibly overcome drug resistance. The promising results with a number of chemical inhibitors of ATM, Chk1 and Chk2 are paving the way for new chemoradiation strategies that exploit the DDR machinery
Surgical-orthodontic therapy of an impacted second molar with the use of low friction orthodontic mechanisms
No full textResting energy expenditure and body composition in morbidly obese, obese and control subjects
No full textResting energy expenditure (REE) was investigated by indirect calorimetry in relation to body composition and to different degrees of obesity in order to assess if a defective energy expenditure contributes to extra body fat accumulation. Differences were found between control subjects (group C; BMI 23±0.5 kg/m2, REE 5890±218 kJ/day; mean±SEM) and obese subjects (group O; BMI 34.2±0.9 kg/m2, REE 7447±360 kJ/day;P<0.0001) and between group C and morbidly obese subjects (group MO; BMI 49.9±1.6 kg/m2, REE 8330±360 kJ/day;P<0.0001); REE was not significantly different between groups O and MO. Body composition data were obtained by means of body impedance analysis. Even though group MO had a fat mass higher than group O, body cell mass, the metabolically active body compartment, was similar in groups O and MO, and this fact may have contributed to the similar REE in the two groups. Multiple regression analysis gave the following equation as the best predictor of REE: REE (kJ/day)+1591±49BW+74BCM-737G (R2=0.88), where BW is body weight, BCM is body cell mass and G is a dummy variable coding group membership (group C=1; group O=2; group MO=3). Thus the analysis showed a negative impact of obesity on REE beyond body composition variables. © 1994 Springer-Verlag
«Io non accuso, non giudico; spiego»: Napoleone III negli scritti di Tommaseo
No full textThe essay analyzes the political evaluation of Niccolò Tommaseo on the role played by Napoleon III in the path of Italian unification. In this sense, the issues concerning the relationship between the Church and the nascent Italian state are particularly interesting, especially as regards political theories and relations between European nations
The Saccharomyces cerevisiae SDA1 gene is required for actin cytoskeleton organization and cell cycle progression
No full textThe organization of the actin cytoskeleton is essential for several cellular processes. Here we report the characterization of a Saccharomyces cerevisiae novel gene, SDA1, encoding a highly conserved protein, which is essential for cell viability and is localized in the nucleus. Depletion or inactivation of Sda1 cause cell cycle arrest in G 1 by blocking both budding and DNA replication, without loss of viability. Furthermore, sda1-1 temperature-sensitive mutant cells arrest at the non-permissive temperature mostly without detectable structures of polymerized actin, although a normal actin protein level is maintained, indicating that Sda1 is required for proper organization of the actin cytoskeleton. To our knowledge, this is the first mutation shown to cause such a phenotype. Recovery of Sda1 activity restores proper assembly of actin structures, as well as budding and DNA replication. Furthermore we show that direct actin perturbation, either in sda1-1 or in cdc28-13 cells released from G 1 block, prevents recovery of budding and DNA replication. We also show that the block in G 1 caused by loss of Sda1 function is independent of Swe1. Altogether our results suggest that disruption of F-actin structure can block cell cycle progression in G 1 and that Sda1 is involved in the control of the actin cytoskeleton
L’isola delle città felici : riflessi d’Europa nella letteratura politica siciliana (secoli XVII-XIX)
No full textIl saggio ricostruisce il tema della felicità pubblica nella letteratura politica siciliana, mettendo in risalto l'originalità con cui soprattutto nelle opere poco note o cadute in oblio è trattato e proposto rispetto alle principali concezioni europee che si diffondono e circolano tra i secoli XVII-XIX
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