Study of the cellulose-peptide conjugation for the development of antimicrobial cotton textiles

openThe aim of this thesis is the study of chemoselective ligations in the context of antimicrobial tissues. Cotton is the chosen textile because it is a natural fiber, widely produced, air permeable and easy to functionalize. The selected class of antimicrobial agents are antimicrobial peptides. In fact, they present a broad-spectrum mechanism of action. Thus, they are at a lower risk for the resistance development; they are produced by the immune system of different organisms, thus inherently biocompatible and biodegradable. Thiazolidine and oxime bonds are the selected ligation methods. They are formed by the reaction of an aldehyde and a β-amino thiol (Cysteine) and an alkoxyamine (Aminooxyacetic acid), respectively. The use of a covalent bond is due to the requirement to produce a functionalized textile that is durable, washable and reusable. The aldehyde is introduced at the C6 atom of the glucose unit of cotton cellulose by an enzymatic oxidation in a 2,2,6,6-Tetramethyl-1-piperidinyloxyical(TEMPO)/laccase/O2 system, whereas the Cysteine (Cys) and Aminooxyacetic acid (Aox) are introduced during the peptide synthesis at the N-terminal. Both the oxidizing and the conjugation reactions are interesting for the mild conditions at which they take place. All the peptides are synthetized through solid phase peptide synthesis (SPPS). Two model peptides are used for the study of the two ligation types. They both have a UV-vis active side chain, a detectable side chain and either a Cys or an Aox. The first is needed to follow the course of the reaction, the second allows to confirm the presence of the peptide on cotton by colorimetric tests and the last two are necessary for the effective ligation with the oxidized cotton. FT-IR analysis is performed to further confirm the presence of the peptides on cotton. The main goals of using these peptides are: the quantification of the peptide loading on different types of cotton, the rough estimation of the aldehyde content on cotton upon the re-use of the oxidizing solution and the evaluation the stability of the two bonds in different media. Finally, a short analogue of PMAP-36, an antimicrobial peptide, is linked to cotton using the above-mentioned strategy and the antimicrobic activity of the obtained material is tested

Functional interaction between BDNF and Kidins220: a study in primary mouse astrocytes and in an adult conditional knock-out mouse model

Neurotrophins are a family of growth factors known for their pleiotropic effects on neuronal survival, maturation and plasticity. Brain-derived neurotrophic factor (BDNF) is the most expressed in the brain. The activation of specific BDNF downstream pathways hinges on BDNF binding to its receptor TrkB. Kidins220 is a scaffold protein that interacts with neurotrophin receptors and is directly involved in the activation of neurotrophin signaling. It is also required for neuron differentiation, survival and plasticity. This protein has been linked to several diseases including psychiatric and neurodegenerative pathologies and for this reason, several KO animal models have been generated. So far none of them was viable after birth, making it impossible to investigate the role of this protein in postnatal/adult brain development. Astrocytes are fundamental in maintaining nervous system homeostasis. They are capable of perceiving a wide variety of extracellular cues and transducing them via the activation of specific intracellular signaling pathways into responses that may be protective or disruptive toward neighboring neurons. Moreover, astrocytes are key regulators of neuronal circuit formation and synaptic transmission. Several aspects of astrocyte physiology are controlled by neurotrophins. However, the role of Kidins220 in astrocytes, as well as in the adult brain remains largely unknown. Thus, in this thesis we aimed to deeply understand the role of Kidins220 using both in vivo and in vitro models. First we compared the signaling competence of embryonic and postnatal primary cortical astrocytes exposed to BDNF, and observed a shift from a kinase-based response in embryonic cells to a predominantly Ca2+-based response in postnatal cultures. We demonstrated that Kidins220 ablation is accompanied by a decreased expression of both BDNF receptor TrkB isoforms. We also described the role of Kidins220 in BDNF-induced signaling in astrocytes, showing that it contributes to both kinase and Ca2+-activated pathways. To evaluate the effect of Kidins220 ablation in the adult brain we used a floxed line that expresses only the full-length isoform, which we crossed with mice expressing Cre under the CamKII promoter, leading to a conditional knockout (cKO) line where Kidins220 is absent only in the excitatory neurons of the forebrain, starting at the second postnatal week. In this animal model, we have observed altered dendritic arborization and spine number in the cortico-hippocampal regions. The deletion of Kidins220 also leads to behavioral changes, such as reduced anxiety-like traits due to to alterations in TrkB-BDNF signaling. Our data increase the knowledge of the complex role played by Kidins220 both in astrocytes and in adult brains, reveal a previously unidentified role of this protein in astrocytes, controlling the response to BDNF and to Ca2+ dynamics during development. Finally, our data confirm the fundamental role of Kidins220 in adult mice, where its ablation leads to both behavioral and biochemical impairments

On the Use of Large Area Tactile Feedback for Contact Data Processing and Robot Control

The progress in microelectronics and embedded systems has recently enabled the realization of devices for robots functionally similar to the human skin, providing large area tactile feedback over the whole robot body. The availability of such kind of systems, commonly referred to as extit{robot skins}, makes possible to measure the contact pressure distribution applied on the robot body over an arbitrary area. Large area tactile systems open new scenarios on contact processing, both for control and cognitive level processing, enabling the interpretation of physical contacts. The contents proposed in this thesis address these topics by proposing techniques exploiting large area tactile feedback for: (i) contact data processing and classification; (ii) robot control

A survey of the past earthquakesin the Eastern Adriatic (14th to early 19th century)

Focusing on the Eastern Adriatic region, from Zadar in the north to Corfu in the south, the background information supporting our knowledge of the seismicity in the time-span 14th to early 19th century is discussed from the point of view of the historical earthquake records. The late 19th century seismological compilations turn out to be those responsible for the uneven spatial and temporal distribution of seismicity suggested by current parametric earthquake catalogues. This awareness asked for a comprehensive reappraisal of the reliability and completeness of the available historical earthquake records. This task was addressed by retrieving in the original version the information already known, by putting the records in the historical context in which they were produced, and finally by sampling historical sources so far not considered. Selected case histories have been presented in some detail also. This material altogether has shown that i) current parameterisation of past earthquakes in the Eastern Adriatic should be reconsidered in the light of a critically revised interpretation of the available records; ii) collecting new evidence in sources and repositories, not fully exploited so far, is needed. This should aim mostly at overcoming another limitation affecting the evaluation of full sets of earthquake parameters, that is the few observations available for each earthquake. In this perspective, an optimistic assessment of the potential documentation on this area is proposed

Alien Registration- Begin, Albini B. (Lewiston, Androscoggin County)

https://digitalmaine.com/alien_docs/22721/thumbnail.jp