644 research outputs found
Gli idrogel per la ricostruzione e la rigenerazione del tessuto muscolare scheletrico
No full textIl tessuto muscolare scheletrico costituisce circa il 40% della massa corporea ed è di fondamentale importanza per un organismo in quanto è responsabile dei movimenti, della postura e dell’equilibrio, oltre che di importanti funzioni metaboliche.
La perdita di questo tessuto può essere causata da una malattia progressiva oppure da un danno accidentale e tuttavia il muscolo scheletrico ha la capacità di rigenerarsi in modo rapido e completo così da prevenire la perdita di massa muscolare. Le cellule satelliti, cellule localizzate tra la membrana plasmatica e la lamina basale di ciascuna fibra, sono considerate le cellule staminali muscolari: in occasione di un qualsiasi processo degenerativo, esse vengono attivate ed iniziano a proliferare. Le cellule figlie migrano per formare catene di cellule satelliti disposte longitudinalmente sotto la lamina basale, qui si fondono tra di loro o con altri miotubi preesistenti per formare nuove fibre muscolari multinucleate. Le cellule satelliti hanno una limitata capacità proliferativa e probabilmente non possono sostenere molteplici cicli di rigenerazione durante fasi ripetute di degenerazione e rigenerazione, ciò è verosimilmente la causa della natura progressiva delle distrofie muscolari.
L’ingegneria tissutale del muscolo, ovvero l’utilizzo di un’impalcatura artificiale a supporto di mioblasti/cellule staminali, sta delineandosi da alcuni anni come una strategia terapeutica innovativa per la cura di molte malattie del sistema muscolare scheletrico. Lo scopo dell’ingegneria tissutale è recuperare tessuti ed organi persi, danneggiati o compromessi, partendo da cellule proliferanti in coltura per terminare con strutture cellulari differenziate tessuto-simili. La matrice extracellulare (ECM) gioca un ruolo essenziale nel determinare il comportamento delle cellule durante i processi di rimodellamento tissutale che portano a strutturare tissuti maturi. Quindi, è auspicabile controllare il differenziamento cellulare durante la rigenerazione del tessuto, mimando l’ECM mediante l’uso di materiali ingegnerizzati. La modifica delle proprieta’ biofisiche e meccaniche di questi biomateriali puo’ essere usata come strategia per indurre risposte cellulari specifiche. Inoltre, un biomateriale iniettabile sotto forma di idrogel, avendo queste caratteristiche, ha come vantaggio ulteriore quello di essere facilmente engrafted in vivo al fine di trasportare cellule staminali e/o molecole bioattive per promuovere il rinnovamento tissutale.
La nostra ricerca ha avuto come scopo l’utilizzo di un idrogel iniettabile fatto di glicole polietilenico (PEG) coniugato al fibrinogeno, il PEG-fibrinogeno (PF). Questo biomateriale è stato usato come scaffold per la ricostruzione muscolare in vitro ad opera di mesoangioblasti (Mabs), cellule progenitrici mesodermiche associate ai vasi, e di mioblasti (cellule satelliti, SCs) isolati freschi. Inoltre il PF è stato testato come carrier per il delivery dei Mabs in vivo al fine di incrementare il processo rigenerativo di muscoli danneggiati.
Gli scaffold di PF usati per le colture in tre-dimensioni in vitro hanno permesso una buona sopravvivenza cellulare ed hanno accelerato il processo differenziativo in muscolo scheletrico, portando alla formazione di miotubi contrattili entro le ventriquattro ore (normalmente, le colture in due dimensioni richiedono tre giorni prima di esibire la formazione di miotubi). Inoltre, utilizzando il biomateriale con un disegno più complesso, cioè contenente al suo interno dei microcanali creati con la microablazione laser, il PF ha permesso l’allineamento delle cellule lungo i canali, quindi il differenziamento e la formazione di fibre muscolari mature ben orientate.
In una prima serie di esperimenti in vivo siamo riusciti ad indurre il differenziamento di tessuti simil muscolo da PF e Mabs impiantati sotto la cute in topi immunodeficienti. Il PF ha mostrato di essere in grado di promuovere la crescita ed il differenziamento dei precursori miogenici, proprio come accade in vitro, portando alla formazione di un vero e proprio organoide, senza dare segni di tumorigenicità. Nella seconda serie di esperimenti in vivo, invece, il PF è stato usato come carrier di Mabs in muscoli danneggiati (tibiali anteriori) di topi immunodeficienti. La presenza del PF ha permesso un’aumentata sopravvivenza delle cellule trapiantate, una migliore ritenzione cellulare in situ e un complessivo miglioramento nell’engraftment cellulare, che si è tradotto in una più rapida rigenerazione del tessuto danneggiato.
In conclusione, i biomateriali ed in particolare gli idrogel come il PF possono essere facilmente utilizzati per il trasferimento di cellule muscolari scheletriche, mediante una semplice procedura di iniezione one-step, e quindi potrebbero avere un enorme impatto nel trattamento di patologie degenerative a carico dei muscoli scheletrici, come la distrofia muscolare.Tissue engineering aims to replace lost, damaged or failing tissue and organs, starting with cultured proliferating cells and ending with tissue-like structures. The extracellular matrix (ECM) plays a pivotal role in determining cell behavior during tissue remodelling processes leading to complete differentiated structures. Therefore it is desirable to control cell differentiation during tissue regeneration by mimicking the ECM using engineered biomaterials. To modify the biophysical and mechanical properties of these biomaterials can be used as a strategy to elicit specific cellular responses. Moreover, an injectable hydrogel biomaterial, having such capabilities, should have the advantage to be easily engrafted in vivo in order to carry stem cell and/or bioactive molecules to promote tissue renewal.
Our research is thus focused on the use of an injectable hydrogel made from polyethylene glycol (PEG) conjugated to Fibrinogen. The PEG-Fibrinogen (PF) is used as scaffold for in vitro muscle reconstruction, seeded and cultured with mesoangioblasts (vessel associated progenitor cells) and freshly isolated muscle satellite cells (SCs). The PF, which can be controlled in terms of its matrix modulus, is tested in vivo as mesoangioblast carrier for muscle regeneration.
The PF scaffold used for in vitro 3-D cultures promoted good survival of miogenic precursors and accelerated skeletal muscle differentiation (contractile myotubes) within 24 hours (normally, 2-D cultures take three days to exhibit myotube formation). The confining geometry of the microchannels created with microablation in the PF scaffolds promoted the development of oriented mature muscle fibers. Sub-cutaneous PF/miogenic precursors implants in Rag2 Chain -/- mice were able to form a “muscle organoid”. Finally, in vivo experiments using PF as a cell carrier showed increased transplanted cell survival, ameliorated in situ cellular retention and an overall improvement in cell engraftment.
Injectable hydrogel biomaterials can be readily applied for skeletal muscle cell delivery by a simple one-step injection procedure and could have a noteworthy impact in the treatment of muscular dystrophy
Online resources for mathematics in the scientific virtual reference desk
No full textThe present work briefly describes the Virtual Reference Desk for mathematics elaborated during the time I worked at the CERN Library (European Laboratory for Particle Physics or Laboratoire européen pour la physique des particules) in Geneva. This instrument is dedicated to the CERN librarians, with whom I have shared important moments of my professional career. In particular, I would like to gratefully acknowledge their valuable co-operation and assistance during our time spent working together. The Web metasource is comprised of three directories, annotated and interrelated with dual application: The first is intended as a work tool for librarians working in mathematics libraries, but above all for librarians of high energy physics, who more often than not must turn to mathematics and the use of mathematical applications and models for the physical sciences and in particular particle physics. The second is an on-line resource for mathematics; that is, a Virtual Reference Desk for the community of mathematicians, with whom I have been collaborating for some twenty years at the University of Padova. The bibliographical instrument is born from the need to have at our disposal a scientific Virtual Reference Desk created according to the needs of those working in physics and mathematics libraries – a tool which is comprised of materials collected during years of work as much as material available on-line through the use of new technologies
Aplicación de las herramientas de costos a la producción de tortas
No full textLa presente investigación se propone indagar y analizar como la implementación de una estructura de costos en un emprendimiento específico permite mejorar la tomar decisiones tanto operativas como estratégicas.
La investigación implicó realizar un análisis cuantitativo, correlacional, microsocial, empírico y sincrónica o seccional. A partir de datos de la entrevista realizada a la dueña del emprendimiento se analizan los costos que posee el mismo y se elabora una estructura de costos para dicho emprendimiento. Luego se evalúa como mejora el uso de la herramienta propuesta la toma de decisiones.
Los resultados indican que: 1) al no poseer una estructura de costos, la dueña del emprendimiento no realiza un cálculo exacto de los mismos, lo que no permite conocer el resultado operativo que realmente obtiene, y que puede llegar a influir en la toma de decisiones erróneas que pueden afectar negativamente al negocio y; 2) La implementación de la herramienta mejora las decisiones operativas y estratégicas, ya que permite el conocimiento de la rentabilidad que brinda cada uno de los productos que se ofrecen, posibilitando de esta manera, mejorar la obtención de ganancias.Fil: Biondo López, M. Antonella. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: Guerrero, Mariana Elizabeth. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: Sottano, Virginia. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas
Intervista con Antonella De Robbio, Responsabile del Settore Progetti e Biblioteca Digitale del Centro d'Ateneo per le Biblioteche CAB dell' Università di Padova e Referente per il diritto d'autore del Sistema Bibliotecario di Ateneo
No full textThe interview with Antonella De Robbio – manager of the “Project Sector and Digital Library” for CAB (Centro di Ateneo per le Biblioteche) of the University of Padua and copyright expert for Sistema Bibliotecario di Ateneo – was published in Pinali news.
Antonella De Robbio answered the following questions:
1) How to deal with the issues of author’s intellectual and economic rights in the context of scientific publishing and digital library?
2) What is the influence of the digital approach on the traditional ways to create and disseminate scientific communication?
3) In your opinion, can the experiences of University Press and the Open Archives represent the path to follow in order to overcome the paradox that a scientific author is also the user of his publisher?
4) Which are the outcomes of the fight between copyright and copyleft?
5) Which of these approaches are more suitable to label the metaphor of the “Society of Knowledge”
Literacy in Neapolitan Women's Convents in the Middle Ages and the Contribution of Digital Archives on Monasterium.Net
No full textAntonella Ambrosio seeks a viable way of carrying out research on this topic: the palaeographic analysis of the few available sources using a multidisciplinary approach that combines diplomatics, archival, and historical research. This approach ensures the appropriate contextualization of the source both historically and culturally. In "Literacy in Neapolitan Women's Convents: An Example of Female Handwriting in a Late Fifteenth-Century Accounts Ledger", Ambrosio provides a case study, analysing a single piece of handwriting evidence. The source is an accounts ledger from the Dominican convent of Santi Pietro e Sebastiano compiled in the second half of the fifteenth century, from 1485 to 1496. Using an analytical approach, the author has identified the handwriting of a particular (anonymous) nun from the convent; Ambrosio studies the script the nun used and formulates hypotheses about her cultural background and how she learned to write. The palaeographic analysis is fully contextualized thanks to the reconstruction of the old convent archive, a reconstruction helped by using digital technologies now accessible online at Monasterium.net. As Ambrosio's work demonstrates, technological advances may aid codicological work but careful palaeographic analysis is necessary to ascertain the participation of female scribes. In this case we witness the scribal development of a nun who began with a basic knowledge of writing and who went on to perform her practical task not well but adequately for the purpose
Literacy in Neapolitan Women’s Convents: An Example of Female Handwriting in a Late Fifteenth-Century Accounts Ledger
No full textThis paper is about a research i on the literacy and writing skills of Neapolitan sisters in medieval convents, due to the lack of adequate historical study of such nuns and the extremely complex nature of the documentary sources. Surviving evidence is scattered far and wide, and the old convent archives have been dispersed. Given the state of the survivals, Antonella Ambrosio seeks a viable way of carrying out research on this topic: the palaeographic analysis of the few available sources using a multidisciplinary approach that combines diplomatics, archival, and historical research. This approach ensures the appropriate contextualization of the source both historically and culturally. In ‘Literacy in Neapolitan Women’s Convents: An Example of Female Handwriting in a Late Fifteenth-Century Accounts Ledger’, Ambrosio provides a case study, analysing a single piece of handwriting evidence. The source is an accounts ledger from the Dominican convent of Santi Pietro e Sebastiano compiled in the second half of the fifteenth century, from 1485 to 1496. Using an analytical approach, the author has identified the handwriting of a particular (anonymous) nun from the convent; Ambrosio studies the script the nun used and formulates hypotheses about her cultural background and how she learned to write. The palaeographic analysis is fully contextualized thanks to the reconstruction of the old convent archive, a reconstruction helped by using digital technologies now accessible online at Monasterium.net. As Ambrosio’s work demonstrates, technological advances may aid codicological work but careful palaeographic analysis is necessary to ascertain the participation of female scribes. In this case we witness the scribal development of a nun who began with a basic knowledge of writing and who went on to perform her practical task not well but adequately for the
purpose
How special are special sciences?
No full textThis essay deals with issues such as the unity of science, the autonomy of the special sciences, reductionism, physicalism, and the role that the concept of emergence plays in the debate about these topics. The author develops her point of view through critical examination of three significant perspectives held in contemporary epistemological discussion. Thus, according to Jerry Fodor, three theses are entailed by reductionism: the generality of physics, token physicalism, and reductionism itself (that is, the idea that every natural kind predicate of a special science is related to a natural kind predicate of physics). Fodor maintains that, in order to safeguard the autonomy of the special sciences, the reductionist thesis should be given up, as a consequence of the validity of the multiple realization thesis. Besides the generality of physics, only token physicalism is needed to guarantee both the autonomy of the special sciences and the unity of science on a physicalistic basis. However, reacting to Fodor’s thesis, Jaegwon Kim points out that adoption of token physicalism leads to consequences which are undesirable for the supporters of the autonomy of the special sciences. Moving from assumptions also shared by non-reductive physicalists, Kim argues that reductionism comes up again through “local reductions” and that, as a consequence, sciences such as psychology are devoid of any disciplinary unity. In the author’s view, Kim’s conclusions show that, in order to safeguard the autonomy of the special sciences, token-physicalism needs to be abandoned along with reductionism. In the context of present-day philosophy of science, John Dupre’s perspective is taken as an example of a position which gives up both of these conditions along with the unity of science thesis, as traditionally understood. The alternative to physicalism and to reductionism is an epistemological and ontological pluralism, according to which the different domains and levels of reality display autonomous characteristics and autonomous causal powers. But how should these latter be conceived? Does downward causation finds its place in the picture? The author’s aim in the final part of her essay is to show that Dupré’s allegiance to a liberalized form of empiricism is incompatible with an autonomous form of mental causation as well as with the most typical characteristics of the human being as a personal agent. The conclusion is drawn that in the particular case of psychology as the science of the mental, the last of Fodor’s conditions, the generality of physics, should also be rejected. Instead, a strong form of emergent property-dualism should, as a minimum, be accepted
Electronic Dictionaries for Information Retrieval, Automatic Textual Analysis and Semantic-Based Data Mining Software
No full textToday Lexicon-Grammar (LG) remains one of the most consistent
Natural Language Processing (NLP) approaches, especially for
Semantic-Based Data Mining (SBDM) and Semantic Web. Its main goal
is to describe all mechanisms of word combinations closely related to the
concrete use of lexical units and to sentence creation. Also, it gives an
exhaustive description of lexical and syntactic structures of several
languages. LG was set up by the French linguist Maurice Gross during
the ‘60s, and subsequently developed for and applied to Italian by
Annibale Elia, Emilio D’Agostino and Maurizio Martinelli. Its
theoretical approach is prevalently based on Zelig Sabbettai Harris’
Operator-Argument Grammar, which assumes that each human language
is a self-organizing system, and that the syntactic and semantic properties
of a given word may be calculated on the basis of the relationships this
word has with all other co-occurring words inside given sentence
contexts. Simple sentences2 are the minimal linguistic meaning structures
upon which LG founds its studies on natural language syntactic features.
In the last twenty years, LG has also reached important results in the
domain of automatic textual analysis and parsing with NLP-oriented
software such as INTEX3, UNITEX4, and more recently NOOJ5.
1 Alberto Postiglione is author of paragraph 4.1. Mario Monteleone is author of
paragraphs 3.1 and 4. Federica Marano is author of paragraphs 3.2 and 4.3. Johanna
Monti is author of sections 1 and 2. Antonella Napoli is author of paragraph 4.2.
2 In LG, a simple sentence is formed by a unique predicative element (a verb, but
also a name or an adjective) plus all the necessary arguments it selects to achieve
acceptability and grammaticality. The study of simple sentences is completed analyzing
the rules of co-occurrence and selection restriction, which are distributional and
transformational rules based on predicate syntactic-semantic properties.
3 For more on INTEX, see http://intex.univ-fcomte.fr/.
4 For more on UNITEX, see http://www-igm.univ-mlv.fr/~unitex/.
5 For more on NooJ, see http://www.nooj4nlp.net/pages/nooj.html.
ALBERTO POSTIGLIONE - MARIO MONTELEONE -
FEDERICA MARANO - JOHANNA MONTI - ANTONELLA NAPOLI1
Università degli Studi di Salerno
ELECTRONIC DICTIONARIES FOR INFORMATION RETRIEVAL,
AUTOMATIC TEXTUAL ANALYSIS AND SEMANTIC-BASED
DATA MINING SOFTWARE
1. Theoretical and analytical framework: Lexicon-Gramma
L'identità, la morte, l'ago della memoria. Salva con nome di Antonella Anedda
No full textIl saggio analizza e commenta la raccolta di poesie di Antonella Anedda "Salva con nome", con riferimenti intertestuali ad altre opere in versi e in prosa della stessa autrice. Individua puntuali caratteri di stile e i nuclei fondamentali della sua poetica, in particolare il significato della memoria, il rapporto con i morti, l'importanza dei gesti di cura, l'influenza delle radici geografiche e culturali.The essay analyzes and comments on the collection of poems by Antonella Anedda "Salva con nome", with intertextual references to other works in verse and prose by the same author. The essay identifies the core nuclei of Anedda's poetics, in particular the meaning of memory, the relationship with dead or desappeared beloved, the importance of gestures, the influence of geographic and cultural roots
Performance evaluation of active RFID location systems based on RF power measures
No full textIn this paper we provide a general and repeatable experimental evaluation campaign of location algorithms based on RSSI measures for active RFID systems. We start from the well-known LANDMARC approach and conduct a thorough investigation aiming at evaluating its actual potentials and limitations under different environmental conditions. For the sake of completeness, we compare its behavior with the one of a further technique, named RSSI Spatial Interpolation (RSI), which is taken as a representative of a wider family of solutions which also LANDMARC belongs to. Experimental results show that by even introducing some modifications, still both algorithms get poor performance in indoor scenarios; location errors lower than 2m are only attainable in limited size outdoor environments in 90% of the experiment
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