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Role of vegetable grafting in the control of abiotic stresses and effects on yield and quality
No full textThe large-scale spread of vegetable grafting was initially promoted to increase tolerance to biotic stresses, however, grafting onto appropriate rootstocks showed up to improve scion performances under many abiotic stress conditions and often resulting in higher yield levels. Low temperature stress is one of the main issues in pepper cultivation. Genetic variability for abiotic stress tolerance is low inside the species and the number of rootstocks available for pepper is limited. Aiming to increase germplasm availability for pepper grafting and to find a rootstock that could alleviate chilling stress, grafting compatibility of Capsicum pubescens and Capsicum baccatum accessions originated from high altitudes with a widespread pepper cv was assessed and grafted transplants were used in chilling stress experiments. Two of these accessions were able to increase biomass accumulation under low temperatures compared to a commercial rootstock and showed no yield decrease or quality worsening when cultivated under optimal temperature conditions. Tomato is both a widespread crop and a model plant and it is usually grafted in specialized agricultural systems. In soilless cultivation, tomato plants can experience root hypoxia as a consequence of both misjudgments in water requirements and the progressive decrease of the air capacity of the substrate over the cultivation cycles. Commercial rootstocks with a different genetic origin were tested for their effectiveness to increase tolerance to roots hypoxia and it resulted in better physiological performances of grafted plants compared to self-grafted ones under stress conditions.
The effects of grafting on yield and quality traits of tomato often depend on the specific rootstock-scion combinations. Through an experiment in which seven cherry tomato cultivars were grafted onto eight rootstocks, including both interspecific and intraspecific hybrids and compared to un-grafted plants, it was possible to identify some variables in which the role of the scion prevailed and others in which rootstock contribution was predominant. The analysis of the coefficients of variation, compared to the absolute values observed in each grafting combination, provided information regarding the ability of rootstock and scion to influence the different examined variables and on its potential benefits
DNA methylation, diet and retinal degenerative diseases
No full textThe present study reveals the role of DNA methylation process in the pathophysiology of retinal degenerative diseases, exploiting a multiple integrated approach. Findings from in vitro studies uncovered how pathological features of retinal degeneration - including oxidative stress, inflammation and hyperglycaemia - modulate DNMTs and SIRT1 functions, affecting LINE-1 methylation levels in retinal cells. However, what we have seen in retinal cells differed from that observed in peripheral blood of AMD patients. Thus, further research - which takes into account genetic susceptibility - is needed to understand the mechanistic underpinnings of retinal degeneration. In addition, we proved that resveratrol and curcumin may restore DNA methylation changes which occur in cells under oxidative, inflammatory or high glucose conditions. The use of these compounds - together with the promotion of healthy diet - represent promising preventive and therapeutic approaches to tackle the increased burden of retinal degenerative diseases
Narrazione e fotografia nel «Politecnico»
No full textLa tesi percorre i fascicoli della rivista «Il Politecnico», diretta da Elio Vittorini dal 1945 al 1947, adottando come lente di ingrandimento gli aspetti che manifestano una significativa apertura all immagine; si scopre così che l articolato contesto fotogiornalistico italiano e americano che fa da sfondo ai fogli del periodico, l ampio apparato illustrativo (e fotografico in particolare), l originale apporto del grafico Albe Steiner possono essere assunti come i poli di riferimento per la lettura di un attivismo vittoriniano che, pur nella apparente distanza dalla produzione narrativa dell autore, mostra non pochi punti di contatto con i tratti distintivi della sua poetica e con le sue più moderne e feconde intuizioni
Differential identities and almost polynomial growth. Star algebras and cocharacters.
No full textThe purpose of this thesis is to present some recent results on the polynomial identities of algebras with derivations and of algebras with involution.
First, we study in detail the differential polynomial identities of the algebra of upper triangular matrices over a field of characteristic zero when two distinct Lie algebras of derivations act on it. We explicitly determine a basis of the corresponding differential identities, the sequence of codimensions and the sequence of cocharacters in both cases. Furthermore, we study the growth of differential identities in both cases. In particular we prove that when the Lie algebra of all derivations acts on , then the variety of differential algebras with action generated by has no almost polynomial growth.
Afterwards, we study of the differential identities of the infinite dimensional Grassmann algebra over a field of characteristic different from two with respect to the action of a finite dimensional Lie algebra of inner derivations. We explicitly determine a set of generators of the ideal of differential identities of . Also in case is of characteristic zero, we study the space of multilinear differential identities in variables as a module for the symmetric group and we compute the decomposition of the corresponding character into irreducibles. Furthermore, we prove that unlike the ordinary case the variety of differential algebras with action generated by has no almost polynomial growth.
Finally, we study and characterize the algebras with involution over a field of characteristic zero satisfying a polynomial identity such that the multiplicities in the corresponding -cocharacter are bounded by a constant
Metal-TiO2 nanocomposites towards efficient solar-driven photocatalysis
No full textWater, together with energy and food, has been addressed as one of the main urgent problem of humanity. The reduction of fresh clean water sources will definitely lead to huge issues in the next future, especially in developing countries. The conventional wastewater treatments suffer some limitations related to the effectiveness in decontamination (mechanical filtration), in the heavy use of chemicals (chlorination), or in elevate operational costs and energy requirements (desalination and reverse osmosis). In this sense, new materials such as nanocomposites may overcome these issues taking advantage of the peculiar properties of materials at nanoscale. Research on novel nanotechnologies must bring advances in order to contrast and prevent water scarcity and pollution. In order to be effective, these nanotechnologies should run at low operational cost, even in places unequipped by strong infrastructures and in concert with conventional cheap methodologies.
Among the alternative water purification methods, TiO2-based photocatalysis has attracted great attention due to material stability, abundance, non-toxicity and high decontamination efficiency. In this material, electron-hole pairs, generated by light absorption, separate from each other and migrate to catalytically active sites at the surface of the photocatalyst. Photogenerated carriers are able to induce the water splitting reaction and, consequently, to decompose organic pollutants. The main deficiency of this material, related to its large band gap, is that only the UV fraction of the solar spectrum is effective to this purpose. Several approaches have been proposed to overpass this issue and, among them, the use of metal-TiO2 nanocomposites with proper nanostructurarion seems very promising for water purification strategies.
Aim of this work is to investigate the possibility to develop efficient solar-driven TiO2 photocatalyst taking advantage of metallic nanostructures to efficiently couple the incident light to the photoactive semiconductor. Two approaches have been followed: TiO2 nanoparticles obtained via pulsed laser ablation in liquid and optical engineering of multilayered metal-TiO2 thin films. The first approach maximizes the exposed surface, thus enhancing the photocatalytic efficiency. However, in this case nanomaterials is dispersed in the surrounding environment, and in order to avoid this drawback we have investigated, as second approach, the use of metal-TiO2 thin films
Representable functionals and derivations on Banach quasi *-algebras
No full textLocally convex quasi *-algebras, in particular Banach quasi *-algebras, have been deeply investigated by many mathematicians in the last decades in order to describe quantum physical phenomena (see \cite{ankar, ankar1, Ant1, Bag2, Bag6, Frag3,ino, ino1,kschm,Trap3,FragCt}).
Banach quasi *-algebras constitute the framework of this thesis. They form a special family of locally convex quasi *-algebras, whose topology is generated by a single norm, instead of a separating family of seminorms (see, for instance, \cite{Bag1,Bag4,Bag5,btt_meas}).
The first part of the work concerns the study of representable functionals and their properties. The analysis is carried through the key notions of \textit{fully representability} and \textit{*-semisimplicity}, appeared in the literature in \cite{Ant1,Bag1,Bag5,Frag2}. In the case of Banach quasi *-algebras, these notions are equivalent up to a certain \textit{positivity condition}. This is shown in \cite{AT}, by proving first that every sesquilinear form associated to a representable functional is everywhere defined and continuous. In particular, Hilbert quasi *-algebras are always fully representable.
The aforementioned result about sesquilinear forms allows one to select {\em well behaved} Banach quasi *-algebras where it makes sense to reconsider in a new framework classical problems that are relevant in applications (see \cite{Bade,Brat1,HP,Kish,Sakai,trap,weigt,WZ1,WZ2}). One of them is certainly that of derivations and of the related automorphisms groups (for instance see \cite{AT2,Alb,Ant4,Bag8,Brat2}). Definitions of course must be adapted to the new situation and for this reason we introduce weak *-derivations and weak automorphisms in \cite{AT2}. We study conditions for a weak *-derivation to be the generator of such a group. An infinitesimal generator of a continuous one-parameter group of uniformly bounded weak *-automorphisms is shown to be closed and to have certain properties on its spectrum, whereas, to acquire such a group starting with a certain closed * derivation, extra regularity conditions on its domain are required. These results are then applied to a concrete example of weak *-derivations, like inner qu*-derivation occurring in physics.
Another way to study representations of a Banach quasi *-algebra is to construct new objects starting from a finite number of them, like \textit{tensor products} (see \cite{ada,fiw,fiw1,hei,hel,lau,lp,sa}). In \cite{AF} we construct the tensor product of two Banach quasi *-algebras in order to obtain again a Banach quasi *-algebra tensor product. We are interested in studying their capacity to preserve properties of their factors concerning representations, like the aforementioned full representability and *-semisimplicity. It has been shown that a fully representable (resp. *-semisimple) tensor product Banach quasi *-algebra passes its properties of representability to its factors. About the viceversa, it is true if only the pre-completion is considered, i.e. if the factors are fully representable (resp. *-semisimple), then the tensor product pre-completion normed quasi *-algebra is fully representable (resp. *-semisimple).
Several examples are investigated from the point of view of Banach quasi *-algebras
Sviluppo tecnologico ed implementazione clinica degli scaffold coronarici bio-riassorbibili.
No full textLa ricerca riportata nel presente elaborato è stata focalizzata sull'emergente tecnologia degli stent coronarici riassorbibili (BRS, bioresorbable scaffold), con l obiettivo di generare dati a medio e lungo termine che potessero contribuire a chiarire il comportamento di tale tecnologia nei diversi contesti clinici, a ottimizzarne l uso e a definire gli ostacoli alla sua applicazione ordinaria, per poter definire strategie mirate di sviluppo e miglioramento dell intera tecnologia dei BRS.
Per tale scopo, il presente progetto consta di diversi studi che possono essere raggruppati in:
- valutazione dei risultati clinici a medio termine associati all impianto del BRS Absorb;
- analisi di sottogruppo da registri monocentrici e multicentrici del BRS Absorb;
- registro con survey multicentrica mirata a valutare nella pratica clinica quotidiana i criteri di selezione dei pazienti da trattare con i BRS;
- documenti di consenso mirati a definire la tecnica di impianto ottimale e la selezione dei pazienti e delle lesioni potenzialmente candidate all'impianto del BRS Absorb;
- analisi mediante tecniche di imaging intravascolare mirate a valutare le caratteristiche dell interazione tra lo scaffold e la parete coronarica, che possono traslare in outcome clinici;
- valutazione dei risultati clinici a lungo termine associati all impianto del BRS Absorb.
Le caratteristiche e i risultati di tali studi sono stati riportati nel presente elaborato finale
Profiling of circulating microRNAs in body fluids from Autism Spectrum Disorder patients
No full textAutism Spectrum Disorder is the name for a heterogeneous group of neurodevelopmental conditions, clinically defined by: defects in social interaction and communication; fixed interests and repetitive behaviors. Molecular basis of ASD is heterogeneous and only partially known. ASD-associated variants have been characterized in hundreds of genes and separate transcriptome studies have identified points of convergence among these loci, proving that common biological processes play a role in this disorder. However, no common ASD-associated variants with large effect size, that would be appropriate for its molecular diagnosis, have been identified to date, and therefore, diagnosis just relies on clinical assessment and confirmation. Many factors, including disorders comorbid with ASD, like Tourette Syndrome, complicate ASD behavior-based diagnosis and make it vulnerable to bias. Extracellular microRNAs have attracted researchers for their potential as non-invasive tools for diagnosis, prognosis, and treatment evaluation of human diseases and disorders. Circulating miRNAs can be detected in all mammalian body fluids, from serum to saliva. Stability and general consistency of levels among individuals, along with the existence of specific expression signatures in association with both physiological and pathological conditions, make circulating miRNAs appropriate biomarkers. To investigate ASD etiology and to identify potential biomarkers to support its diagnosis, we used TLDA technology to profile serum miRNAs from ASD, TS, and TS+ASD patients and NCs (unaffected controls). Through validation assays, we demonstrated that miR-140-3p is upregulated in ASD vs: NC, TS, and TS+ASD. We found that delta Ct values for miR-140-3p and YGTSS scores are positively correlated. Our network functional analysis showed that nodes controlled by miR-140-3p, especially CD38 and NRIP1, are involved in processes convergingly dysregulated in ASD, such as synaptic plasticity, immune response, and chromatin binding. Through biomarker analysis, we proved that serum miR-140-3p can discriminate among ASD and NC, ASD and TS, and ASD and TS+ASD, showing that it could be useful to strengthen the behavior-based diagnosis of either ASD or TS+ASD, which can be challenging in some clinical cases. Among all body fluids, saliva represents the most accessible and complete source of different types of molecules that could reflect genetic, epigenetic, environmental, metabolic, emotional, and behavioral alterations in ASD. Therefore, we also used NanoString nCounter technology to profile supernatant saliva circulating miRNAs from ASD patients and NCs. Through validation assays, we demonstrated that both miR-29a-3p and miR-141-3p are upregulated in ASD saliva compared to NC one. We observed that delta Ct values for both miRNAs are correlated with neuropsychiatric scores evaluating ASD defects in social interaction and verbal communication. Target genes of these miRNAs represent main components and regulators of pathways and processes known to be dysregulated in ASD. Through biomarker performance evaluation, we proved that saliva miR-29a-3p and miR-141-3p when used in combination could be useful and non-invasive tools for discriminating ASD patients. In particular, these miRNAs could be used as supportive means for the recognition of ASD verbal and social defects. Overall, our findings suggest that profiling of circulating miRNAs in body fluids can represent an easy and innovative approach to address important biomedical issues, such as the need for biomarkers and the necessity to investigate neurodevelopmental disorders through more accessible patient biopsies. In fact, through the characterization of miRNAs in ASD serum and saliva, we identified three miRNAs that could facilitate ASD clinical assessment and that are worth being further investigated for their potential role in neurodevelopment
High resolution linear spectropolarimetry: a study of the potentiality in probing stellar atmospheres and circumstellar environments
No full textPolarimetry is considered as an important searching tool in Astronomy and it deserves to be a standard observational technique for a variety of astrophysical environments. Many phenomena, in fact, can contribute to the polarisation of radiation and so, its observation can potentially provide information about their basic causes. In particular, in a stellar context high resolution spectropolarimetry can potentially: (i) investigate the physics of the shaping mechanisms of the protoplanetary nebulae (PNe) and the possible interaction between the central star and the very close surrounding, (ii) investigate stellar photospheric inhomogeneities (e.g. pulsations, granulations, hot spots and magnetic activity), (iii) play a key role in the exoplanet research. Despite this, however, the difficulties involved in the measurements and in the theoretical interpretation made this technique not as widespread as it deserves.
The main goal of this work is to demonstrate the diagnostic potential of high resolution linear spectropolarimetry. At this purpose, we studied the polarised spectrum of the post-AGB binary system 89 Herculis on the basis of data collected with the high resolution \emph{Catania Astrophysical Observatory Spectropolarimeter} (CAOS) and \emph{HArps-North POlarimeter} (HANPO), in addition to archive data taken with the \emph{Echelle SpectroPolarimtric Device for the Observation of Stars} (ESPaDOnS). We found the existence of linear polarisation in the metal lines in absorption and in some of the metal lines in emission: this is the first \emph{Second Solar Spectrum} ever observed in a star different than the Sun. We have then analyzed the observed polarisation properties. Firstly, regarding the polarisation measured across the absorption lines, we found that the complex Stokes and morphologies vary with the orbital period of the system. We then rule out magnetic field, continuum depolarisation due to pulsations and hot spots as a possible origin. We found that in the framework of optical pumping due to the secondary star, the observed periodic properties of the spectral line polarisation can be justified by two jets, with a flow velocity of a few tens of , at the basis of that hourglass structure characterizing 89 Herculis. Regarding the emission lines, numerical simulations show that these polarised profiles could be formed in an undistrupted circumbinary disk rotating at and with an orientation in the sky in agreement with optical and radio interferometric results. We have concluded that the study of aspherical envelopes, the origin of which is not yet completely understood, of PNe and already present in post-AGBs can benefit from high resolution spectropolarimetry and that this technique can shape envelopes still too far away for interferometry.
In addition, we have conducted a large spectropolarimetric survey on a sample of F-G-K bright stars to understand if the presence of intrinsic linear polarisation is a rare case or it is widespread in these type of stars. Surprisingly, we have found linear polarisation across metal lines in absorption for about of stars of our sample. Some of them clearly show temporal variability, to be characterized with further data. Despite this study is neither exhaustive nor conclusive we speculated that the presence of linear polarisation in the stars is not rare: a broad and in-depth spectropolarimetric study is then necessary
First trimester combined test in high risk population
No full textIntroduction
Down Syndrome (DS) is the most common chromosomal abnormality and the risk to have an affected baby relates directly to maternal age. Invasive prenatal diagnosis based on advanced maternal age (AMA) alone is still a large contributor to invasive testing (amniocentesis and villocentesis). However, there are many reasons to abandon screening on the basis of AMA, given its low detection rate (DR), the risk of fetal loss (0,5-1%) and high costs for the national health systems (NHS).
The aim of our study was to evaluate the performance of the first trimester combined screening test (CT) plus markers in women aged 35 years or older.
Materials and methods
From February 2016 and September 2018 we prospectively enrolled 493 women aged 35 or older, referred to the Fetal Medicine Clinic Policlinico G. Rodolico University Hospital, Catania Italy. After counseling 259 (52,5%) women chose to have an invasive test (group A) while 234 (47,5%) underwent the CT plus (group B), reserving the right to choose the invasive test after receiving the results.
Results
The incidence of DS was similar in both group, 2.3% in group A and 1.7% in group B. The DR for the CT was 100% for a 12.5% of false positive rate (FPR); by the additional use of first trimester markers, the presence of the nasal bone (NB), the evaluation of the ductus venosus blood flow (DV) and tricuspid regurgitation (TR), we were able to reduce the FPR at a value of 2%. During the study period we observed a 19.6% reduction of invasive procedures and a 60% increase in the uptake of CT in women aged 35 or older.
Conclusions
The additional use of first trimester markers, NB, DV and TR, is feasible and it reduces FPR without any additional costs for NHS. We provide evidence that adequate Down syndrome screening policy are the best way to reduce the rate of invasive procedures and to improve costeffectiveness.
In conclusion this study demonstrates that maternal age is not an appropriate criterion for Down syndrome screening when CT plus is available