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Self-Assembled Monolayers of aromatic thiols on gold and copper in aqueous environment: an electrochemical and spectroscopic study
No full textThiolate Self-Assembled Monolayers (SAMs) offer the unique opportunity to tailor surface
properties of noble and coinage metal in extremely fine way through a simple bottom-up
approach, making them very attractive in a wide range of technological applications. On
copper surfaces, n-alkanethiolate monolayers have been extensively studied as corrosion
inhibitors in aqueous solutions revealing excellent performances but relatively poor stability,
a problem affecting SAMs in many of them applications. On the other hand, very few studies
have been performed on SAMs constituted by simple aromatic thiols and none of them
assessed their long term stability, although the relatively strong ring interaction should in
principle positively affect the layer durability.
In the present work the protective properties and the long term stability in strongly acidic
solution (H2SO4 0.5 M) of two aromatic SAMs, namely Benzenethiol (BT) and 2-
Naphthalenethiol (2-NT) was compared to that of one long-chain n-alkylic SAM, the 1-
Undecanethiol (1-UT) by means of XPS, Raman spectroscopy, DCA and electrochemical
techniques. The results not only demonstrated the aromatic SAMs to be remarkably stable,
but also highlighted a favourable influence of the aqueous environments on the layers
structures, resulting in a durable enhancement of their protective properties.
Subsequently, the effect of different p-substituent groups (-F, -CH3, -OH, -COOH, -
NHCOCH3) on the performance and the stability of the aromatic SAMs was investigated.
All such molecules, similarly to BT, showed a steep increase of their inhibition efficiency
upon ageing. The rate and the durability of the enhancement resulted mainly dependent from
the polar effect of the tail group; moreover, the hydrophobicity seems to influence the
protective properties of the layers as well.
Finally SAMs of BT and 1-UT on gold, both freshly prepared and aged in ultrapure water,
were characterized electrochemically. Again BT layers showed an improvement of their
structural order following the exposure to aqueous environments, indirectly supporting the
hypothesis of a direct involvement of water molecules in this process. In addition, a new
method to prepare high quality aromatic SAMs on gold has been proposed
IL CASO DI STUDIO ASPETTI EMOTIVI NELL'APPRENDIMENTO DI UNA DISCIPLINA
No full textRILEVANZA DELLA LOGICA FUZZY PER LA RICERCA SOCIALE E COSTRUZIONE DI UNA SCALA DI ATTEGGIAMENTO FUZZ
Le lesioni mammarie a potenziale neoplastico incerto (B3) diagnosticate su Core Needle Biopsy (CNB): inquadramento clinico, out come e valutazione dell’opzione chirurgica
No full textTITLE: "Uncertain malignant potential breast lesion (B3) diagnosed on core needle biopsy (CNB): clinical presentation, outcome and evaluating surgical option"
INTRODUCTION Core needle biopsy (CNB) have been introduced to increase the accuracy of diagnosis of breast cancer and to exclude from surgery benign lesions, with savings of injured tissues. However, a fair percentage of CNB are still classified, according to European guidelines, in the B3 category, which includes a heterogeneous group of lesions with uncertain malignant potential. The aim of this study is to evaluate the positive predictive value (PPV) on excisional biopsies (EB) after the diagnosis of B3 in our experience at Campus Bio-Medico of Rome and compare them with data in the literature to evaluate the possibility of a different treatment for each histological subgroup.
MATERIALS AND METHODS: From May 2003 to May 2011 were performed 808 CNB, stereo as well as US guided, at the Breast Unit of the Campus Bio-Medico. One hundred and sixteen of these (14.4%) were classified as B3. Ninety-five patients (81.9%) underwent BE.
RESULTS It was confirmed the diagnosis of CNB in 47 cases (49.5%), in 31 (32.6%) definitive histology was of benign lesions, in 14 cases (14.7%) cancer in situ , ductal or lobular, was diagnosed, and in three (3.1%) an invasive cancer was detected. Overall, the PPV is of 17.9%. In particular, all malignant lesions were associated with atypia. Lobular Intraepithelial Neoplasia (LIN) grade 2 and 3 showed, at histological examination of EB, respectively PPV of 54.5% and of 66.7%, while LIN1 of 15.8%. In our series Ductal Intraepithelial Neoplasia (DIN) 1a and b have a PPV of 12.5% and 4%. Aftere the diagnosis of 6 papillary lesions, EB showed foci of carcinoma in situ inone case (PPV 16.7%).
Two/8 radial scars, both associated with DIN1, were tumors in situ at the excisional biopsy.
Excisional biopsy confirmed the other types of lesions (Phyllodes tumors, Fibroepithelial lesions).
DISCUSSION AND CONCLUSIONS The European Guidelines for the Diagnosis of breast cancers define B3 "lesions that may be benign on histology of BE, but it is known that heterogeneity can show, or have an increased risk (although low) to be associated in malignant lesions. " In our series the PPV was 17.9% and is associated in all cases but one (papillary lesions) with ductal or lobular intraepithelial neoplasia (LIN and DIN1-b). At a review of the literature, we believe that with a diagnosis of B3 at the CNB is mandatory a EB if is present LIN2 and 3 and recommended in LIN1 and DINA-b. We also propose that should be sent to EB every atypical papillary lesions and phyllodes tumor, because of the natural history of these tumors. Instead the opportunity of EB in other types of lesions classified B3 should be discussed in multidisciplinary meetings.
REFERENCES
Bianchi S. “Positive predictive value for malignancy on surgical excision of breast lesions of uncertain malignant potential (B3) diagnosed by stereotactic vacuum-assisted needle core biopsy (VANCB): a large multi-institutional study in Italy” Breast 2011; 20; 264-270
European Commission Working Group on Breast Screening Pathology. Quality assurance guidelines for pathology. Perry N. Ed. Luxemburg: Office for official publications of the European Communities; 2006: 219-312Aim of this work is to identify subclass of breast lesion unknown malignant potential with an higher Positive Predictive ValueNon
Studio delle proprietà ottiche e termiche di opali sintetici e acciai tramite tecniche fototermiche
No full textIn this thesis the study of thermal and optical properties of synthetic opals and stainless steels are investigated using photothermal technique
Wave generation and propagation at tribological interfaces
No full textWave generation and propagation at contact interfaces is a relevant issue in mechanics because they affect directly a large number of mechanical systems involving either static or sliding frictional parts. Contact dynamics is at the origin of friction induced vibrations, acoustical instabilities, surface damage, wear and fatigue failures [IBRA 94][AKAY 02] Propagating waves at the interface can be exploited for controlling the global friction features of the contact.
Beside classical experiments, numerical analysis on dry contacts in sliding state has been one of the mayor topic in recent literature to which a relevant number of important papers have been dedicated ([RENO 11] and reference therein), due also to the fact that it is a substantial subject of interest for researchers working on many different domains, from dynamics to tribology and geophysics.
At the origin of the phenomena cited above there is the wave generation and propagation at the frictional contact interface. Moreover when the two materials in contact are different, the dynamics of the phenomenon increases in complexity due to the so-called "bimaterial" effect ([WEER 80][ADA 95][BEN 01] and reference therein).
This thesis is addressed to the understanding of the mechanisms at the origin of the contact wave fields and its relationship with the local characteristics of the surfaces in contact, as well as with the global dynamics and macroscopic frictional behaviour of the system. The aim of this work is to provide insights on the generation and propagation of the waves through the contact both to avoid instabilities and to control their effect on friction. The work is organized in two main parts.
The first part presents the development of a non-linear finite element analysis in large transformations of the dynamic rupture at the interface with contact friction separating two bodies (isotropic and elastic) without relative motion. A rupture is considered when an initially sticking zone shifts in sliding state. The properties of the obtained ruptures are analyzed for a flat interface between dissimilar materials in function of the nucleation energy; then the effect of the interface roughness is analyzed. The differentiated rupture inside the asperities and the conditions for coupling and uncoupling between the waves radiating in the two bodies have been also investigated.
In the second part, the analysis deals with the sliding onset between two bodies in contact. The sliding between two bodies made of different isotropic elastic materials and separated by a frictional interface is simulated. The evolution along the time of the global normal and tangential forces is analyzed, relating it to the local phenomena occurring at the interface. This part tries to investigate how micro-slips at the interface, acting as distributed ruptures, trigger the macro-slips between the two bodies. The interaction between local and global dynamics is also studied. Finally a numerical parameter space study is carried out, as a function of several system parameters (contact law, friction coefficient, material damping, normal load, translational velocity and regularization time).
The results show the key role of the micro-slips and precursors (detectable wave propagations that occur at tangential global force well below the critical value expected by the friction law) in triggering the macro-slip between the two bodies. Depending on their distribution and magnitude the evolution of the contact forces passes from stick-slip-like behaviour to continuous sliding. The local dynamics at the contact (wave and rupture propagation) is linked to the global behaviour of the system (stick-slip, continuous sliding, induced vibrations); the effect of the contact and system parameters on the transfer of vibrational energy between the sliding contact and the system is investigated.
The numerical results obtained by the two parts of the work show a good agreement with experimental results in literature.French-Italian Universit
“Potential biological meaning and origin of cardiac progenitor cells isolated as Cardiospheres"
No full textSeveral populations of progenitor cells have been identified in the adult heart, based on the expression of specific surface markers (c-kit, Sca1), or on functional properties, such as the ability to spontaneously migrate from tissue explants and grow in three dimensional structures, called cardiospheres (CSs). CSs represent a niche-like microtissue with a cardiogenic gradient of differentiation towards the periphery. It is not clear which is the origin of these endogenous progenitor populations and how they function in vivo, given the limited regenerative capacity of the heart. Several possibilities can be envisioned. These cells could be remnants of the embryonic development, or derive from the de-differentiation of cardiomyocytes. To test this hypothesis we used a double transgenic mouse expressing the recombinase MerCreMer under the cardiomyocyte-specific αMyosin-Heavy-Chain promoter. After a pulse with 4OH-tamoxifen (TAM) the activated Cre removes a stop signal between two LoxP sequences, allowing the expression of the reporter gene LacZ, in a spatial and temporal regulated manner. Ideally with this system all the differentiated cardiomyocytes should be irreversibly labeled after TAM treatment, even if they subsequently undergo de-differentiation. B-gal positive cells were very rare in culture, as shown by x-gal staining and real time PCR, suggesting that cardiomyocytes de-differentiation is not the main mechanism underlying CSs formation. However, given the limited sensibility of this method (the efficiency of recombination in the cardiomyocytes is 80% at maximum), we cannot conclusively exclude the occurrence of this phenomenon. Using another transgenic mouse strain, in which epicardial and epicardial-derived cells are labeled, we observed a large number of positive cells at all culture stages. Our hypothesis, supported by RT-PCR data, is that epicardial-derived cells undergo mesenchyma-to-epithelium (MET) transition during cardiospheres formation. This is consistent with a recent report presenting MET as a crucial mechanism in cell reprogramming.Pasteur Institute- Cenci Bolognetti Foundatio
Tecniche di rappresentazione contemporanee interattive: limiti e potenzialità
No full textViene condotta una valutazione critica relativa all'introduzione sperimentale della Realtà Aumentata in ambiti di natura
architettonica e di rappresentazione multimediale interattiva ad essi relativi.Lo studio condotto concerne lo sviluppo di applicazioni su piattaforme di Realtà Aumentata, finalizzate a ricostruzioni
virtuali di beni architettonici
A Study of the Principles of the Ideal Urban-Architecture for the 21st century
No full textThe perception of the ideal utopia changes based on the different contexts such as
politics, social, cultural and historical conditions and technologies. The cities reflect
these states of mind which are transformed through urban evolution. There are
factors concerning the ideal city as the spirit of the time that affect the urban form.
The goal of this study is to define these factors to understand and analyze the
characteristics of the ideal urban-architecture of the 21st century.
Utopia is the basic concept. Historically, the aim of the space called “city” has been a
utopia for the human civilization. Hence, first, I analyze the relationship between
utopia and the ideal city through investigating urban characteristics chronologically,
based on the urban theories and plans relating to the changes of thought on utopian
urban-architecture. Then, I also investigate several accomplished urban plans of
cities in the 20th century as practical case studies to understand how urban theories
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and planning have been implemented.
To examine this, I investigate contemporary urban plans as an example of
contemporary ideal urban-architecture. The 8 cities selected as case studies are
classified in 3 categories: Urban, District and Self-sufficiency. The selection was made
considering construction time, geographical location, objects, and key functions.
Through these processes of research it is shown that the concept of utopia plays an
important role in the development of the urban structure throughout time, even when
it has been difficult to be realized in an urban structure physically. And the process of
research makes it possible to draw the common constructive principles, which were
used to operate on the ideal urban-architecture, from the analysis of the flow of
urban-planning in history.
As a result, they can be categorized in three main factors for constructive principles of
the ideal city: Perception, Compression, and Technology.
Perception is related to the utopian thought that has concretized as
the image for the future. It is based on real experiences, or at least
imaginable experiences.
Generally speaking, perception has changed dynamically relying on
the different time periods and in new perceptions; it doesn’t matter
if it is positive or negative, it criticizes reality and plays an
important role in the creation of a utopian society.
Time and space are very significant factors as indexes in the ideal
urban-architecture, based on the utopian thought.
Compression of time and space physically influences the urban form
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in the construction of the ideal urban-architecture. The form and
structure of the ideal urban-architecture has been dynamically
transforming in relation to the level of this compression of time and
space.
Since the 19th century, the fundamental motif for the ideal cities is to
overcome time and space in people’s daily life. The progress of the
ability to overcome time and space has rapidly affected the
perception of the society. Then, it has also played a key role in the
construction of the ideal urban-architecture.
Technology has been a key factor as a tool in the progressive flow of
the ideal urban-architecture. It worked together with the other two
principles: Perception and Compression. It accelerated the
compression of time and space and renewed the perception on time
and space at the same time.
The technology of the steam engine caused the automation system
in the industrial field, and it gave people freedom from natural time
and labors. Besides, the progress of transportation: train, steamship,
car, airplane, etc., also accelerated the speed of the compression of
time and space in the 19th and in the early 20th century.
In the late of 20th century the progress of information and
communication has brought the concept of synchronization and the
virtual world into our daily lives.
Thanks to these new technologies, people can have new experiences
in terms of time and space and the boundary of perception has been
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getting wider and deeper at the same time.
As a conclusion to this study I analyzed and summarized the concept of the ideal
urban-architecture towards the 21st century under those three constructive principles.
It is shown that they create the spirit of the time for the ideal urban-architecture of
the 21st century. In fact, the paradigm for the 21st century can be analyzed under these
three constructive principles. It is significant to identify the direction of ideal urbanarchitecture
in the 21st century
Tall Building. Infrastrutture verticali per il riequilibrio energetico dell’ambiente urbano.
No full textThe Thesis has the general aim to inquire on tall buildings in relation to the quest for a more sustainable future, by going through research on their potential capability to produce energy from renewable sources.
The final result is a systematic framework of tall buildings morphological and functional features related to building and renewable energy sources systems, and identifies critical elements and design variables as well, usefull for comparing tall buildings with targets such as Net Zero Energy Building and Plus Energy Building.
The thesis is divided into three thematic areas. First of all, it investigates the tall buildings’ embodied and operational energy, by going through the most up-to-date literature and post occupancy evaluation data. The specific aim is to identify innovatory architectural strategies aimed at enhancing the energy efficiency of tall buildings. The second part of the research looks into the potential that tall buildings have of generating power from renewable sources. On the basis of an analysis of the technologies for generating power from renewable energy sources, the criticalities and the potential of each system implemented in tall buildings have been highlighted, focusing on the key issues of integration, maintenance and safety. Finally, a targeted selection of case studies, both built and experimental designs, are aimed to outline the state of the art, in terms of the implementation of renewable energy generation systems in tall buildings