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Time-and Solvent-Dependent Self-Assembly of Photochromic Crystallites
No full textMolecular self-assembly provides complex structures and enables the tuning of system features on the nanoscale. Guided assembly, induced by external stimuli, gives hierarchical but static arrangements, limiting the exploitation in several fields. A dynamic arrangement can confer improved and smarter properties, but adaptive self-assembly requires new molecules and the knowledge of kinetics effects. The interest in adaptive self-assembly is constantly growing and comprises environmental-, chemical-, and field-adaptive molecules. Thus reversible adaptive self-assembly systems, which can be build and destroyed for several times, attract large attention. To contribute in this field, we report the particular post-solvato-control on solid habit morphology of the vinyl-terminated spiropyran derivative named 1-(5-hexenyl)-3,3-dimethyl-6′-nitro-1,3-dihydrospiro[2H-indole-2,2′-[2H][1]benzopyran. For this molecule, the formation of supramolecular structures is solvent- and time-governed and exhibited reversible isomerization upon UV irradiation. We observed different solid habits by varying solvent polarity as well as an increasing degree of arrangement with time. Light-induced precipitation in nonpolar solvent afforded spherical merocyanine aggregates under mild conditions. This example of kinetics-controlled photochromic system has the potential to drive toward adaptive and dynamic self-assembly systems, with application in material science and for polymer functionalization
Does corporate control matter to financial volatility?
No full textIn our contribution we study how the ownership channel affects the stock price volatility
of listed stock markets. In particular, we study how a linkage between a parent company and
its affiliates may drive differences in stock price volatility, within and across countries. We
exploit a worldwide dataset of stock-exchange listed firms, controlling for several financial
dimensions, to assess whether business groups matter to financial volatility. The answer is
positive and does not depend on the definition of volatility used. Our results contribute to
the corporate finance literature by defining the role of multinational corporate control in
financial markets, and to the financial stability literature by assessing corporate control as
an undiscovered channel of transmission for financial shocks
Functional and spatial segregation within the inferior frontal and superior temporal cortices during listening, articulation imagery, and production of vowels
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Molecularly Imprinted Biodegradable Nanoparticles
No full textBiodegradable polymer nanoparticles are promising carriers for targeted drug delivery in nanomedicine applications. Molecu- lar imprinting is a potential strategy to target polymer nanoparticles through binding of endogenous ligands that may promote recognition and active transport into specific cells and tissues. However, the lock-and-key mechanism of molecular imprinting requires relatively rigid cross-linked structures, unlike those of many biodegradable polymers. To date, no fully biodegradable molecularly imprinted particles have been reported in the literature. This paper reports the synthesis of a novel molecularly- imprinted nanocarrier, based on poly(lactide-co-glycolide) (PLGA) and acrylic acid, that combines biodegradability and molec- ular recognition properties. A novel three-arm biodegradable cross-linker was synthesized by ring-opening polymerization of glycolide and lactide initiated by glycerol. The resulting macromer was functionalized by introduction of end-functions through reaction with acryloyl chloride. Macromer and acrylic acid were used for the synthesis of narrowly-dispersed nanoparticles by radical polymerization in diluted conditions in the presence of biotin as template molecule. The binding capacity of the imprinted nanoparticles towards biotin and biotinylated bovine serum albumin was twentyfold that of non-imprinted nanoparti- cles. Degradation rates and functional performances were assessed in in vitro tests and cell cultures, demonstrating effective biotin-mediated cell internalization
Law no. 1089 of 1 June 1939. The Origin and Consequences of Italian Legislation on the Protection of the National Cultural Heritage in the Twentieth Century
Get PDFThe author seeks to set out a criticism of the alleged innovations brought about by the 1939 Italian law on the “Protection of objects of artistic or historical value”. The law came in those years during which Fascist authorities struggled to keep on national soil a great deal of cultural property, which belonged to those who were trying to flee Italy following the harshening of persecutory regulations. Yet, scores of valuable public and private works of art had been reaching Nazi top brass following the Italian government’s own initiative. This eventually hindered the legitimacy of part of the cultural restitutions granted to Italy by the Allied military authorities after 1945
The double role of GDP in shaping the structure of the International Trade Network
No full textThe International Trade Network (ITN) is the network formed by trade relationships between world countries. The complex structure of the ITN impacts important economic processes such as globalization, competitiveness, and the propagation of instabilities. Modeling the structure of the ITN in terms of simple macroeconomic quantities is therefore of paramount importance. While traditional macroeconomics has mainly used the Gravity Model to characterize the magnitude of trade volumes, modern network theory has predominantly focused on modeling the topology of the ITN. Combining these two complementary approaches is still an open problem. Here we review these approaches and emphasize the double role played by GDP in empirically determining both the existence and the volume of trade linkages. Moreover, we discuss a unified model that exploits these patterns and uses only the GDP as the relevant macroeconomic factor for reproducing both the topology and the link weights of the ITN
Periodic Optimal Control, Dissipativity and MPC
Get PDFRecent research has established the importance of (strict) dissipativity for proving stability of economic MPC in the case of an optimal steady state. In many cases, though, steady-state operation is not economically optimal and periodic operation of the system yields a better performance. In this technical note, we propose ways of extending the notion of (strict) dissipativity for periodic systems. We prove that optimal P-periodic operation and MPC stability directly follow, similarly to the steady-state case, which can be seen as a special case of the proposed framework. Finally, we illustrate the theoretical results with several simple examples
Long-term EVA degradation simulation: climatic zones comparison and possible revision of accelerated tests
No full textPeripersonal space representation develops independently from visual experience
No full textOur daily-life actions are typically driven by vision. When acting upon an object, we need to represent its visual features (e.g. shape, orientation, etc.) and to map them into our own peripersonal space. But what happens with people who have never had any visual experience? How can they map object features into their own peripersonal space? Do they do it differently from sighted agents? To tackle these questions, we carried out a series of behavioral experiments in sighted and congenitally blind subjects. We took advantage of a spatial alignment effect paradigm, which typically refers to a decrease of reaction times when subjects perform an action (e.g., a reach-to-grasp pantomime) congruent with that afforded by a presented object. To systematically examine peripersonal space mapping, we presented visual or auditory affording objects both within and outside subjects’ reach. The results showed that sighted and congenitally blind subjects did not differ in mapping objects into their own peripersonal space. Strikingly, this mapping occurred also when objects were presented outside subjects’ reach, but within the peripersonal space of another agent. This suggests that (the lack of) visual experience does not significantly affect the development of both one’s own and others’ peripersonal space representation