Synthesis and characterisation of hyperbranched polymers

Hyperbranched polymers are a subclass of dendritic molecules characterised by a highly branched architecture. Such polymers are usually prepared in an easy and affordable one-pot synthesis and therefore are considered suitable for industrial large-scale applications such as coating and resins formulation. Hyperbranched poly(ester amine)s (PEAs) and poly(amido amine)s (HPAMAMs) were synthesised by the double monomer methodology (DMM) with multifunctional monomers. The Michael addition reaction was used with and A2 + B4 methodology. The use an A2 + B4 system has the advantage of producing hyperbranched polymers with high number of functional terminal groups but also the disadvantage of (potentially) undergoing gelation due to the use of monomers with symmetric functionalities. Therefore a key project aim was the development of novel, simple, versatile and cost-efficient synthetic strategies to exclusively synthesise soluble (gel-free) hyperbranched polymers via the A2 + B4 system. It was also an objective of this work to (i) further modify/functionalise the chemical structure of the resulting hyperbranched polymers, (ii) understand the long-term (storage) stability of the synthesised polymers and (iii) explore potential industrial applications. PEAs and HPAMAMs were synthesised by selecting suitable pairs of monomers (A2 and B4) with a molar ratio of A2:B4 which was higher than 1:1 (A:B (>2):4). The reactions studied show susceptibility to gelation and at long reaction times the formation of a cross-linked product or alternatively a sol-gel product was observed in many cases. In this latter case the relative amount of gel and soluble (sol) fraction was found to be dependent on the reaction conditions used such as monomer molar ratio, temperature and monomer solution concentration. A first strategy to produce exclusively soluble branched polymers involved the use of a large stoichiometric excess of A2 monomer with respect to B4 monomer and quenching the polymerisation after a certain time. It was observed that at a molar ratio A2:B4 of 3:1, highly branched and gel-free polymers were formed and after 24 hours (i) for HPAMAMs, a polymer with Mn 620 g/mol, Mw 10550 g/mol, Ð 17.7 and degree of branching (DB) 0.98 was obtained in methanol/water at 40°C while (ii) for PEAs, a polymer with Mn 620 g/mol, Mw 1150, Ð 1.8 and DB 0.45 was formed at 60°C in DMF. A novel alternative strategy was developed with the above-mentioned requirements, that enabled the synthesis of soluble branched polymers without the need to monitor and stop the reaction at a certain conversion of functional groups above which gelation occur. Moreover, a variety of effective and versatile strategies for the modification of the basic polymer skeleton of HPAMAMs were explored. The stability of PEAs was studied in methanol and evidence of degradation was found both by SEC analysis and NMR spectroscopy. It was shown that degradation occurred via cleavage of the ester group of the polymer catalysed by the amine groups within the same structure. The stability of HPAMAMs towards degradation was instead studied in water and a good long-term stability both in dilute and in concentrated solution was observed by SEC analysis and NMR spectroscopy. However, HPAMAMs underwent chain-coupling in water which did lead in some cases to gelation. Polymers were hence modified in order to reduce the risk of gelation. The properties of the HPAMAMs polymers synthesised by A2 + B4 system were finally investigated and proved to be of potential commercial utility in certain industrial applications

Differential neural dynamics underling pragmatic and semantic affordance processing in macaque ventral premotor cortex

Premotor neurons play a fundamental role in transforming physical properties of observed objects, such as size and shape, into motor plans for grasping them, hence contributing to "pragmatic" affordance processing. Premotor neurons can also contribute to "semantic" affordance processing, as they can discharge differently even to pragmatically identical objects depending on their behavioural relevance for the observer (i.e. edible or inedible objects). Here, we compared the response of monkey ventral premotor area F5 neurons tested during pragmatic (PT) or semantic (ST) visuomotor tasks. Object presentation responses in ST showed shorter latency and lower object selectivity than in PT. Furthermore, we found a difference between a transient representation of semantic affordances and a sustained representation of pragmatic affordances at both the single neuron and population level. Indeed, responses in ST returned to baseline within 0.5 s whereas in PT they showed the typical sustained visual-to-motor activity during Go trials. In contrast, during No-go trials, the time course of pragmatic and semantic information processing was similar. These findings suggest that premotor cortex generates different dynamics depending on pragmatic and semantic information provided by the context in which the to-be-grasped object is presented

Modern circular economy: corporate strategy, supply chain, and industrial symbiosis

This paper analyses the firms’ chances to consider circular economy as a part of the corporate strategy. The analysis of four Italian firms engaged in circular economy programs allows us to detect its connections with the corporate strategy, the real activities involved, the supply chain network ensuring circularity, the industrial symbiosis, as well as the links with performance. Our findings highlight that circular economy is a true business lever when the corporate strategy complements and supports its development. This allows firms to achieve high level targets that go beyond the traditional targets of social, environmental, and economic performance, and include circular supply chain, eco-innovations, and industrial symbiosis

Modern circular economy: Corporate strategy, supply chain, and industrial symbiosis

This paper analyses the firms\u2019 chances to consider circular economy as a part of the corporate strategy. The analysis of four Italian firms engaged in circular economy programs allows us to detect its connections with the corporate strategy, the real activities involved, the supply chain network ensuring circularity, the industrial symbiosis, as well as the links with performance. Our findings highlight that circular economy is a true business lever when the corporate strategy complements and supports its development. This allows firms to achieve high level targets that go beyond the traditional targets of social, environmental, and economic performance, and include circular supply chain, eco-innovations, and industrial symbiosis

La reconstrucción del pasado reciente en los edificios escolares de Mendoza

Reinhart Koselleck despliega sobre el recuerdo una teoría del lenguaje en la articulación de la experiencia histórica como base de un proyecto historiográfico porque ningún recuerdo ni transposición científica de éste es posible sin el lenguaje. La historia de los conceptos está relacionada con lo social porque los hechos sociales rebasan el lenguaje. Se pueden mencionar diversos modos posibles en los que se pueden vincular el presente, el pasado y el futuro porque existe un distanciamiento progresivo entre el espacio de la experiencia y el horizonte de expectativa que puede ser modificado si ese espacio supera lo generacional y se transforma en un depósito de experiencias o base. Esta investigación vincula dos intervenciones en comunidades escolares que como menciona Koselleck están vinculadas a la experiencia de una generación con sus muertos y su memoria, sea esta descubierta en su proceso de identidad (el ISFD) u ocultada o silenciada (CNAA). En estas instituciones educativas: Colegio Nacional Agustín Álvarez se recuperaron los legajos de 6 ex alumnos que durante la dictadura integrarían la lista de detenidos desaparecidos y el ISFD Tomás Godoy Cruz, convive en su edificio con los restos de la Jefatura que entre 1974 y 1975 funcionó como Departamento de Logística. El “Jardín de la Memoria" es la demanda de identidad y memoria que realiza en ISFD Tomás Godoy Cruz en el embate con los actuales intentos de invisibilización y olvido. En ambas instituciones, el entretejido de tensiones y disputas de territorios de la memoria (Ludmila Da Silva Catela) posibilitan los debates en torno a la memoria y su uso social y político. Lo instituyente y lo instituido se articulan cuando el trabajo de la memoria nace en una institución educativa como una demanda social o se construye en un contexto ideológico e histórico desde el paradigma de DD.HH. pero conviven con modalidades que pretenden en muchas ocasiones debilitar u opacar estos trabajos y es responsabilidad como señala Koselleck de las instituciones y de las generaciones anteriores mantener el sentido de lo que conmemora y celebra.Fil: Balada, Mónica . Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y SocialesFil: Torres, Verónica . Universidad Nacional de CuyoFil: Maranesi, Romina

Processing of own hand visual feedback during object grasping in ventral premotor mirror neurons

Mirror neurons (MNs) discharge during action execution as well as during observation of others’ actions. Our own actions are those that we have the opportunity to observe more frequently, but no study thus far to our knowledge has addressed the issue of whether, and to what extent, MNs can code own hand visual feedback (HVF) during object grasping. Here, we show that MNs of the ventral premotor area F5 of macaque monkeys are particularly sensitive to HVF relative to non-MNs simultaneously recorded in the same penetrations. Importantly, the HVF effect is more evident on MN activity during hand-object interaction than during the hand-shaping phase. Furthermore, the increase of MN activity induced by HVF and others’ actions observed from a subjective perspective were positively correlated. These findings indicate that at least part of ventral premotor MNs can process the visual information coming from own hand interacting with objects, likely playing a role in self-action monitoring

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4 mapes.Evolució històrica d' Europa del secle 3 fins al 1812.- Al revers: vol.5, no.14, 8.- Enciclopedia universale illustrata, lexicon Vallardi.- Obra complerta en 22 vols.- publicat entre 1887-195628 x 39 c

Largely shared neural codes for biological and nonbiological observed movements but not for executed actions in monkey premotor areas

The neural processing of others' observed actions recruits a large network of brain regions (the action observation network; AON) in which frontal motor areas are thought to play a crucial role. As the discovery of mirror neurons (MNs) in the ventral premotor cortex, it has been assumed that their activation was conditional upon the presentation of biological rather than nonbiological motion stimuli, supporting a form of direct visuomotor matching. Nonetheless, nonbiological observed movements have rarely been used as control stimuli to evaluate visual specificity, thereby leaving the issue of similarity among neural codes for executed actions and biological or nonbiological observed movements unresolved. Here, we addressed this issue by recording from two nodes of the AON that are attracting increasing interest, namely, the ventrorostral part of the dorsal premotor area F2 and the mesial presupplementary motor area F6 of macaques while they 1) executed a reaching-grasping task, 2) observed an experimenter performing the task, and 3) observed a nonbiological effector moving in the same context. Our findings revealed stronger neuronal responses to the observation of biological than nonbiological movement, but biological and nonbiological visual stimuli produced highly similar neural dynamics and relied on largely shared neural codes, which in turn remarkably differed from those associated with executed actions. These results indicate that, in highly familiar contexts, visuomotor remapping processes in premotor areas hosting MNs are more complex and flexible than predicted by a direct visuomotor matching hypothesis

The physiological dilemma of the high progesterone syndrome in rabbit does

This work focused on the mechanisms that may cause multiple asynchronous ovulations and alter normal ovarian function in order to characterize the high progesterone (P+) syndrome in rabbit does, that, having abnormally high plasma progesterone concentration at the time of insemination, fail to become pregnant. At different luteal stages, at either days 4, 9, or 13 of pseudopregnancy, induced by GnRH injection (d-0), two groups of rabbits (n=5/group) were treated with saline or 0.8 \ub5g GnRH. Blood samples were collected from d-0 to d-26 of pseudopregnancy. At d-4, GnRH injection prolonged (P<0.05) the functional CL life span by 3 to 4 d over that of controls. At d-9, GnRH caused a transient decline (P<0.01) of progesterone for the following 3 d but, thereafter, increased again and remained higher (P<0.01) than controls up to d-26. At d-13, progesterone fell to 1 ng/ml within one day following GnRH, but then gradually increased. Based of these progesterone profiles, it can be argued that, at both mid- and late-luteal phase, GnRH triggered luteolysis and induced ovulation followed by the formation of a new generation of CL. For the in vitro study, CL, collected at days 4, 9, and 13 of pseudopregnancy, were incubated with GnRH, GnRH-antagonist, PLA2 inhibitor, and PLC inhibitor. GnRH decreased (P<0.01) progesterone secretion by d-9 and d-13 CL cultured in vitro; by converse, GnRH antagonist, increased (P<0.01) progesterone release from d-4 CL. Co-incubation of GnRH with GnRH antagonist increased (P<0.01) progesterone release in d-4 CL, but had an opposite effect (P<0.01) on d-9 and d-13 CL. PLC inhibitor reversed the GnRH effects in both d-9 and d-13 CL, while PLA2 inhibitor did not change progesterone release. These data suggest that rabbit CL express a functional receptor for GnRH, likely of type II, that utilizes the PLC post transductional cascade. Luteal FSH-R and LH-R mRNA relative abundances did not differ between d-4 and d-9 CL, but were two- to three-fold (P 640.01) higher, respectively, at d-13. StAR mRNA was highly expressed at d-4 of pseudopregnancy, but then markedly declined (P 640.01) at d-9 and d-13. Taken together, our results show that GnRH triggers i) functional regression when CL acquire luteolytic capacity from d 9 of pseudopregnancy onward, and ii) multiple asynchronous ovulations, thus partly explaining the P+ syndrome associated with the simultaneous coexistence of two population of \u201cfresh\u201d and \u201cold\u201d CL, although not yet the underlying causes