A new snowfall detection algorithm for high latitude regions based on a combination of active and passive sensors

Precipitation retrieval over high latitudes, particularly snowfall retrieval over ice and snow, using satellite-based passive microwave spectrometers, is currently an unsolved problem. The challenge results from the large variability of microwave emissivity spectra for snow and ice surfaces, which can mimic, to some degree, the spectral characteristics of snowfall. This work focuses on the investigation of a new snowfall detection algorithm specific for high latitude regions, based on a combination of active and passive sensors able to discriminate between snowing and non snowing areas. The space-borne Cloud Profiling Radar (on CloudSat), the Advanced Microwave Sensor units A and B (on NOAA-16) and the infrared spectrometer MODIS (on AQUA) have been co-located for 365 days, from October 1st 2006 to September 30th, 2007. CloudSat products have been used as truth to calibrate and validate all the proposed algorithms. The methodological approach followed can be summarised into two different steps. In a first step, an empirical search for a threshold, aimed at discriminating the case of no snow, was performed, following Kongoli et al. [2003]. This single-channel approach has not produced appropriate results, a more statistically sound approach was attempted. Two different techniques, which allow to compute the probability above and below a Brightness Temperature (BT) threshold, have been used on the available data. The first technique is based upon a Logistic Distribution to represent the probability of Snow given the predictors. The second technique, defined Bayesian Multivariate Binary Predictor (BMBP), is a fully Bayesian technique not requiring any hypothesis on the shape of the probabilistic model (such as for instance the Logistic), which only requires the estimation of the BT thresholds. The results obtained show that both methods proposed are able to discriminate snowing and non snowing condition over the Polar regions with a probability of correct detection larger than 0.5, highlighting the importance of a multispectral approach.

Development of glass-ceramics from combination of industrial wastes together with boron mining waste

The utilization of borate mineral wastes with glass-ceramic technology was first time studied and primarily not investigated combinations of wastes were incorporated into the research. These wastes consist of; soda lime silica glass, meat bone and meal ash and fly ash. In order to investigate possible and relevant application areas in ceramics, kaolin clay, an essential raw material for ceramic industry was also employed in some studied compositions. As a result, three different glass-ceramic articles obtained by using powder sintering method via individual sintering processes. Light weight micro porous glass-ceramic from borate mining waste, meat bone and meal ash and kaolin clay was developed. In some compositions in related study, soda lime silica glass waste was used as an additive providing lightweight structure with a density below 0.45 g/cm3 and a crushing strength of 1.8±0.1 MPa. In another study within the research, compositions respecting the B2O3–P2O5–SiO2 glass-ceramic ternary system were prepared from; borate wastes, meat bone and meal ash and soda lime silica glass waste and sintered up to 950ºC. Low porous, highly crystallized glass-ceramic structures with density ranging between 1.8 ± 0,7 to 2.0 ± 0,3 g/cm3 and tensile strength ranging between 8,0 ± 2 to 15,0 ± 0,5 MPa were achieved. Lastly, diopside - wollastonite (SiO2-Al2O3-CaO )glass-ceramics from borate wastes, fly ash and soda lime silica glass waste were successfully obtained with controlled rapid sintering between 950 and 1050ºC. The wollastonite and diopside crystal sizes were improved by adopting varied combinations of formulations and heating rates. The properties of the obtained materials show; the articles with a uniform pore structure could be useful for thermal and acoustic insulations and can be embedded in lightweight concrete where low porous glass-ceramics can be employed as building blocks or additive in cement and ceramic industries.

Novel prototypes of electro-activated molecular machines

The work presented in this thesis deals with the investigation of new prototypes of molecular machines, based on rotaxane and pseudorotaxane architectures, by means of voltammetric and spectroscopic techniques. The discussion is divided in two parts. Part I concerns the investigation of electro-switchable molecular muscles, based on mechanically interlocked molecules. This study is performed on systems of increasing complexity, starting from [2]rotaxanes and arriving to polymers. In Chapters 3 and 4, [2]- and [3]rotaxanes, characterized by the presence of three stations for the macrocycle(s), are investigated. In both systems, the macrocycle(s) movement can be controlled through a combination of stimuli, resulting in a processive and directional motion. In Chapter 5, daisy chain rotaxanes, dimers of the [2]rotaxanes discussed in Chapter 3, are investigated. These systems can be switched between an extended and a contracted conformation, and they represent the monomeric units for the realization of polymeric molecular muscles. In Chapter 6, the properties of electro-switchable polymeric molecular muscles, composed by the daisy chains investigated in Chapter 5, are discussed. The repeating units of these poly-daisy chains contract and extend upon electrical stimulation, and this motion is expected to be transmitted to the polymer itself, resulting in an amplification of the effect. Part II concerns the investigation of rotaxanes and pseduorotaxanes based on heteroditopic calix[6]arenes and cationic guests. In Chapters 8 and 9, novel calix[6]arene macrocycles, functionalized with thiourea or dansyl units, and their related pseudorotaxanes are investigated. In both cases, the calix[6]arene functionalization adds new features to the pseudorotaxane. In Chapters 10 and 11, the influence of orientational isomerism on the properties of [2]- and [3]rotaxanes is investigated. The [3]rotaxanes discussed in Chapter 10 display similar properties, while the [2]rotaxanes described in Chapter 11, characterized by a calix[6]arene and a stilbazolium unit, exhibit distinct photophysical and photochemical properties.

Azacitidine and Lenalidomide Combination Therapy in Myelodysplastic Syndromes: Topography and Translational Relevance of Nuclear Phospholipase C β - dependent Signalling

Nuclear inositide signalling pathways, and particularly those regulated by PI-PLCβ1, are associated with cell proliferation and differentiation. Myelodysplastic syndromes (MDS) are a heterogeneous spectrum of chronic myeloid hemopathies with associated symptomatic cytopenias and substantial potential for evolution to acute myeloid leukemia (AML). MDS patients are currently treated with two main approaches, epigenetic (Azacitidine) and immunomodulatory (Lenalidomide: above all in cell clones bearing a deletion of the long arm of the chromosome 5 [del(5q)]). As Azacitidine and Lenalidomide alone can show adverse effects or patients can be refractory, an experimental current approach is the combination of the two drugs. Clinically, this combination therapy is promising, while its molecular effect has to be clarified. Stemming from these data, in this study the effect of an Azacitidine-Lenalidomide combination therapy was studied, in both MDS patients and hematopoietic cell lines. The specific aims of this study were to evaluate the effect of Azacitidine and Lenalidomide MDS therapy on: cell cycle regulation, hematopoietic differentiation, gene mutation and miR expression. Lenalidomide alone, via PI-PLCβ1/PKC pathway, was able to induce a selective G0/G1 arrest of the cell cycle in del(5q) cells, slowing down their rate proliferation and favouring erythropoiesis activation. In addition, although the mutation profile at baseline was not entirely capable of predicting the clinical effect of Azacitidine and Lenalidomide therapy, the presence of specific point mutations affecting three inositide genes (PI3KCD, AKT3, PLCG2) was correlated to and anticipated a negative clinical outcome. Moreover, the differential miR expression was detectable even from the 4th cycle of therapy in responder patients, as compared to non-responders. In MDS, this is the first evidence that the molecular mutation profiling of inositide genes or a specific mini-cluster of differentially expressed miRs, targeting inositide signaling molecules, can be associated with the clinical response, thus possibly predicting the effect of the therapy.