32 research outputs found
Investigation of HERC2 and OCA2 SNP for iris color variation in puerto rican paso fino horses
No full textFammi del tuo valor sì fatto vaso, come dimandi a dar l'amato alloro
No full textIl contributo esamina lo sviluppo della possibilità di esistenza di poeti e autori volgari (accanto e in competizione con i classici soprattutto latini)nelle opere di Dante antecedenti la Commedia. Quindi argomenta le ragioni per cui Dante, nella Commedia, si proclama poeta ma non si definisce mai autore (tale in particolare è Virgilio).The contribution considers the development of the possibility of existence of vulgar poets and authors (beside and in competition with the classics, mostly Latin) in Dante's works prior to the Comedy.
Then it argues the reasons why Dante, in the Comedy, declares himself a poet but he never calls himself an author (such is particularly Virgil)
Development and Implementation of a university ambassador concept for Swisscom
No full textThe named IT company aims to belong to the top 3 ICT employers in Switzerland. Although the company invests strongly in university marketing, its student target group does not perceive the employer image as good as its professional target group does. As a consequence, the Employer Branding Team commissioned the author to introduce a new university ambassador concept on the basis of a bachelor thesis.
Following research questions were formulated:
• Can a university ambassador concept increase the overall employer attractiveness among a specific target group?
• Can a university ambassador concept lead to a change of perception among a specific target group in terms of an employer characteristic
Near-infrared photoluminescence of erbium tris(8-hydroxyquinoline) spin-coated thin films induced by low coherence light sources
No full textCopyright 2007 AIP Publishing LLC. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Applied Physics Letters [91, 021106 (2007)] and may be found at
Une lecture probabiliste du cycle d’affaires américain
No full textThis article explores 35 years of the U.S. business cycle with a multivariate hidden Markov model using monthly data. It identifies ten U.S. time series offering particularly reliable information to detect recessions. It also assesses the performances of different and complementary “ recession models ” based on Markov processes and draws two main conclusions : (1) simple univariate models are decisive to monitor the business cycle providing that the series are shown to be highly reliable ; (2) models adding a multivariate dimension are useful but work only marginally better than a simple summary. The primary determinant of model quality appears to be the variables’ information content. The author introduces a new reading of the business cycle using a preferred recession model and concludes by discussing the limitations of leading indicators and “ real-time detection.”En passant en revue 35 ans de “ Cycle d ’ affaires ” à l’aide de modèles à changements de régimes markoviens, cet article permet d’identifier dix séries mensuelles particulièrement fiables pour détecter les “ récessions ” américaines. En testant différents indicateurs synthétiques probabilistes, on remarque que de simples modèles univariés sont déterminants pour suivre le cycle d’affaires et que les performances de modèles incluant une dimension multivariée “ pure ” apportent une information très proche de celle extraite d’un résumé. La qualité d’un modèle semble dépendre avant tout du contenu informationnel des variables qui le constituent. Ce papier conclut sur les propriétés et les limites d’un modèle privilégié de détection de récession, notamment dans son utilisation en temps réel.Bellone Benoît. Une lecture probabiliste du cycle d’affaires américain. In: Économie & prévision, n°172, 2006-1. pp. 63-81
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No full textThe domestic cat (Felis silvestris catus) is a valued companion animal throughout the world. Over 60 different cat breeds are accepted for competition by the cat fancy registries in different countries. Genetic markers, including short tandem repeats and SNPs, are available to evaluate and manage levels of inbreeding and genetic diversity, population and breed structure relationships, and individual identification for forensic and registration purposes. The International Society of Animal Genetics (ISAG) hosts the Applied Genetics in Companion Animals Workshop, which supports the standardization of genetic marker panels and genotyping for the identification of cats via comparison testing. SNP panels have been in development for many species, including the domestic cat. An ISAG approved core panel of SNPs for use in cat identification and parentage analyses is presented. SNPs (n = 121) were evaluated by different university-based and commercial laboratories using 20 DNA samples as part of the ISAG comparison testing procedures. Different SNP genotyping technologies were examined, including DNA arrays, genotyping-by-sequencing and mass spectroscopy, to select a robust and efficient panel of 101 SNPs as the ISAG core panel for cats. The SNPs are distributed across all chromosomes including two on the X chromosome and an XY pseudo-autosomal sexing marker (zinc-finger XY; ZFXY). A population study demonstrated that the markers have an average polymorphic information
content of 0.354 and a power of exclusion greater than 0.9999. The SNP panel should keep testing affordable while also allowing for the development of additional panels to monitor health, phenotypic traits, hybrid cats and highly inbred cats
Characterization, modeling and simulation of 4H-SiC power diodes
No full text2009 - 2010Exploring the attractive electrical properties of the Silicon Carbide (SiC) for power devices, the
characterization and the analysis of 4H-SiC pin diodes is the main topic of this Ph.D. document. In
particular, the thesis concerns the development of an auto consistent, analytical, physics based
model, created for accurately replicating the power diodes behavior, including both on-state and
transient conditions.
At the present, the fabrication of SiC devices with the given performances is not completely
obvious because of the lack of knowledge still existing in the physical properties of the material,
especially of those related to carrier transport and of their dependences on process parameters.
Among these, one can cite the degree of doping activation, the carrier lifetime into epitaxial layers
that will be employed and the sensitivity of some physical parameters to temperature changes.
Therefore, a set of investigative tools, designed especially for SiC devices, cannot be regarded as
secondary objective. It will be useful both for process monitoring, becoming essential to the tuning
of technological processes used for the implementation of the final devices, and for a proper
diagnostics of the realized devices. Following this need, in our research activity firstly a predictive,
static analytical model, including temperature dependence, is developed. It is able to explain the
carrier transport in diffused regions as function of the injection level and turns also useful for better
understanding the influence of physical parameters, which depend in a significant way from the
processed material, on device performances. The model solves the continuity equation in double
carrier conditions, taking into account the effects due to varying doping profile of the junction, the
spatial dependence of physical parameters on both doping and injection level and the modification
of the electric field of the region with the injection regime. The model includes also the device
characterization at high temperatures to analyze the influence of thermal issues on the overall
behavior up to temperature of 250°C. The accuracy of the static model has been extensively
demonstrated by numerous comparisons with numerical results obtained by the SILVACO
commercial simulator.
Secondly, with the aim to properly account for the dynamic electrical behavior of a diode with
generic structure, the static model has been incorporated in a more general, self-consistent model,
allowing the analysis of the device behavior when it is switched from an arbitrary forward-bias
condition. In particular, the attention is focused on an abrupt variation of diode voltage due to an
instantaneous interruption of the conduction current: although this situation is notably interesting
for the study of the switching behavior of diodes, the voltage transitory is also traditionally used in
different techniques of investigation to extract more information about the mean carrier lifetime.
This occurs, for example, in the conventional Open Circuit Voltage Decay (OCVD) technique,
where the voltage decay due to the current interruption is useful for an indirect measure of minority
carrier lifetime in the epitaxial layer.
Because of its heavy dependence on processes, the carrier lifetime is an important parameter to
be monitored, especially in the case of bipolar devices, and it cannot be neglected. Due to the
existent uncertainty about this parameter in SiC epi-layers, the OCVD method reveals itself a
practical way to overcoming this limit.
In detail, by using our self-consistent model, that exploits an improved method of the traditional
OCVD technique, it is possible to characterize the carrier lifetime into 4H-SiC epitaxial layer of a
generic diode under test, obtaining the spatial distributions of the minority carrier concentration and
carrier lifetime at any injection regime. The overall model performances are compared to both
device simulations and experimental results performed on Si and 4H-SiC rectifier structures with
various physical and electrical characteristics. From the comparisons, the model results to have
good predictive capabilities for describing the spatial–temporal variation of carriers and currents
along the whole epi-layer, proving contextually the validity of the used approximations and
allowing also to resolve some ambiguities reported in the literature, such as the stated
inapplicability of the OCVD method on thick epitaxial layers, the reasons of the observed non linear
decay of the voltage with time, and the effects of junction properties on voltage transient.
Finally, with the imposition of right boundary conditions, it is possible to use the versatility of
the developed model for extending the analysis and obtaining a physical insight of any arbitrary switching condition of 4H-SiC power diodes. [edited by Author]IX n.s
Analysis and design of 4H-SiC bipolar mode field effect power (BMFET)
No full text2011 - 2012Analysis and design of a new Silicon Carbide polytype 4H (4H-SiC) bipolar power transistor are
the main topics of this Ph.D. thesis. The device is the Bipolar Mode Field Effect Transistor
(BMFET) and exploits the electric field due to the channel punching-through in order to have a
normally-off behavior and the minority carrier injection from the gate regions into the channel in
order to obtain the channel conductivity modulation. The structure of the transistor is oxide-free and
its advantages are due to the lower conduction resistance, to the higher output current density and
blocking voltage and to the elevated switching frequency, which make it competitive with
commercial 4H-SiC Junction Field Effect Transistors or Bipolar Junction Transistors.
These activities, which have been completed with the definition of the main process steps and of
the mask layouts, are supported by a technology activity and by an intense modeling activity of
BMFET electrical characteristics, which has been validated by comparisons with the results of
numerical simulator (ATLAS Silvaco) and the measures of commercial devices having a similar
structure, like Vertical-JFETs.
In the former activity, in order to obtain an integrated free-wheeling diode in anti-parallel
configuration to BMFET, an original 4H-SiC Schottky rectifier has been fabricated; precisely, for
the first time in the literature, DiVanadium PentOxide (V2O5), a Transition Metal Oxide, has been
used as anode contact of the rectifier. The device is a heterojunction between a thin V2O5 layer,
which is thermally evaporated and has a thickness of around 5nm, and a 4H-SiC n-type low doped
epilayer. By analyzing the JD-VD and CD-VD curves, the structure has a rectifier behavior with a
high/low current ratio higher than seven order of magnitude and its transport mechanism is
described by the thermionic emission theory characterized by a Schottky barrier height and an
ideality factor between 0.78eV and 0.85eV and between 1.025 and 1.06, respectively, at T=298K.
Because the gate doping concentration greatly influences the BMFET performances, as input
resistance, DC current gain and blocking voltage, Aluminum ion implantation process, used to
realize the Gate regions, is strongly analyzed in terms of the dose concentrations and of the
annealing temperature. It will show as the necessity of a low BMFET on-resistance, which is
possible with highly conductive gate regions in order to permit high injection levels of the minority
carriers, is counteracted by the Aluminum incomplete ionization in 4H-SiC. This phenomenon
together with the band-gap narrowing effect limits the hole carrier density from gate to channel.
The analysis, in collaboration with the Institute for the Microelectronics and Microsystems (IMM)
of CNR in Bologna, Italy, consists to reveal the effects of various different doses at different
temperature annealing (1920K and 2170K) on the gate injection efficiency and on the input current
density.
Since the introduction of the first normally-off Si JFET in ‘80 years, the description of the
potential barrier height into the channel has been unresolved due to the complex relations with the
channel geometry and bias conditions. In the second activity an analytical model of the potential
barrier height in the channel is proposed and compared with the numerical simulation results by
changing the channel length and width, respectively in the range 0.1÷6μm e 0.5÷3μm, the channel
doping concentration, between 1014÷1017cm-3, and the output and input bias voltages. Moreover, it
has been also validated by using Silicon as semiconductor material, permitting to extend it to other
devices with similar structures, like BSITs, VJFETs and SITs. From a further improvement of this
model, another has been developed, which is able to describe the trans-characteristics of the
transistor both in sub-threshold condition and in unipolar conduction, and the comparisons with
numerical simulations and experimental data validated the results.
Finally, the analysis of the input diode during the switching-off has been performed because the
switching capability of the BMFET depends on the storage charge into the channel during the “on”
state. The result is the development of an analytical model that describes the spatial distributions of
the electric field, of the minority carrier concentration and of the carrier current densities into the
epilayer at each instant during the switching, in addition obviously to the current and voltage
transients. It is shown as the combination of this model with another static model just developed in
a previous Ph.D. thesis is an useful instrument to understand how physical parameters, which are
dependent on the manufacturing processes, as carrier life-time and doping concentrations, can affect
the dynamic behavior. [edited by Author]XI n.s
Proteomic investigation of the impact of Cannabidiolic acid on Eukaryotic Translation complex in glioblastoma
No full text2021 - 2022Phytocannabinoids, the major secondary metabolites of cannabis plants, exert a wide range
of biological activities. The present work was focused on investigating the mechanism of
action of cannabidiolic acid (CBDA) in U87MG glioblastoma cell line, exploiting the efficacy
of chemical-proteomics based approaches in identifying target proteins of uncharacterized
drugs. DARTS experiments showed Eukaryotic Initiation Translation Factor 2A (EIF2A) as a
putative target of CBDA. This interaction was further validated by western blot and CETSA,
thus showing a thermal stabilization of Eukaryotic Translation Complex conferred by CBDA.
Moreover, Limited Proteolysis showed that the EIF2A C-terminal portion 460-480 could play
a critical role in the molecular recognition of CBDA by the protein. This result was also
confirmed by Molecular Dynamics (MD) calculations, which revealed that CBDA interacts
with a stretch of residues in the 460-480 portion and in the adjacent C-terminal helix, acting
as a bridge between these regions. Hence, since EIF2A is the initiator factor of translation
process, the impact of CBDA-EIF2A interaction on proteins synthesis was investigated by
p-SILAC and enrichment via click-chemistry. Comparing CBDA and EIF2A-silencing
treatments, a similar remodeling of nascent proteome was detected in the two conditions in
terms of protein expression reduction and biological effect. Particularly, CBDA appeared to
induce an UPR response, triggering as a balancing effect between the ER-stress response
and the attempt to restore cellular homeostasis. Moreover, EIF2A revealed to interact not
only with eukaryotic translation proteins but also with the proteins involved in triggering of
UPR response and the CBDA-induced reorganization of eukaryotic translation machinery.
Interestingly, these proteins seem to be involved in several pathways already highlighted by
nascent proteome investigation.
In order to evaluate the protein-CBDA interaction in a cell model closer to the tumor in vivo,
a 3D cell culture was set up using a classic-sandwich model. Based on the observation that
in 2D- and 3D- cell model U87MG cells grow differently since in 3D they show a natural
shape and more cellular interactions, a global proteome comparative analysis was firstly
carried out. Interestingly, the obtained results highlighted a higher-amount of proteins
involved in invasion cellular processes and cell-ECM interaction expressed by 3D-U87MG,
compared to 2D-cultured cells. These findings prompted us to further study the effects of
CBDA in 2D and 3D cellular models. In 3D cultured cells, CBDA showed a different
cytotoxicity depending on the concentration of FBS in the upper and lower- gels and in the
culture medium as well. DARTS assay performed in this cell system also suggested a direct
correlation between the percentage of FBS used in cell culture conditions and the ability of
CBDA to interact with EIF2A, thus confirming the critical role played by the molecule-FBS
interaction on its availability. Furthermore, comparing the results of DARTS assays
performed on 2D and 3D, a difference of the EIF2A interactome with respect to the entire
translational complex was revealed in the two conditions. In contrast to 2D-cellular model,
EIF2A was highly resistant to proteolysis in untreated 3D cultured cells, but was more
digested after CBDA treatment. This result suggested that EIF2A in 3D-U87MG could be
likely associated with the other protein partners more strongly than in the 2D model. In
closing of this study, it is possible to state that the use of a multi-proteomic approach allowed
us to highlight the potential impact of CBDA on the eukaryotic translation machinery, also
suggesting the importance of investigating the interactome differences that exist between
innovative three-dimensional and conventional cellular models. [edited by Author]XXXV cicl
