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Analysis of the growth of microalgae in batch and semi-batch photobioreactors
Get PDFGlobal warming induced by increasing concentrations of greenhouse gases in the atmosphere has become today an important environmental concern. A worldwide problem
has become the depletion of petrochemical fuels and the continuous rise in oil prize that call us to make a global effort in order to find alternative energetic sources.
A gradual replacement of fossil fuels by renewable energy sources (i.e. biofuels) is needed. In this scenario the use of microalgae can be seen as a possible solution to the problem of global warming since this group of fast-growing unicellular organisms shows several advantages (widespread availability, absent competition with agricultural land, utilization of cheap and abundant nutrient sources, high oil and biomass yields, high quality of the byproducts,
generation of biomass for biofuel production with concomitant CO2 sequestration and suitability for wastewater treatments and other industrial plants) which make them one of the most promising and attractive renewable sources for a fully sustainable and lowcarbon
economy portfolio. Despite this growing interest, the current microalgae-based technology is still not widespread since it is affected by technical and economic constraints that hinder its full scale-up. Therefore, great R&D efforts are currently undertaken to produce biodiesel at competitive
costs and with the required quality starting from microalgae feedstock. In particular given the potential benefits of microalgae, their cultivation should be studied and optimized to make them competitive as fuel producing systems in the global market. Coherently to the scenario above reported, this work is focused on the investigation of two microalgae strains, Nannochloris eucaryotum and Chorella vulgaris. In particular, growth kinetics of these strains are investigated by taking into consideration
the effect of medium composition and gas concentration using batch and fed-batch photobioreactors. The aim of this characterization is thus to gain useful information for the cultivation of microalgae in order to optimize the viable production of biofuels and high value-added products at the industrial scale by means of a process which uses flue gases as CO2
Diagnosi prenatale non invasiva di malattie monogeniche attraverso la ricerca e l'isolamento di cellule e DNA fetale nel sangue materno
Get PDFPrenatal genetic diagnosis of monogenic diseases and chromosomal abnormalities is usually performed collecting fetal samples through villocentesis or amniocentesis.
These invasive procedures are associated with 0.5-1% risk for the fetus. Due to it, in recent years, much effort has been made to develop non invasive prenatal diagnosis (NIPD). Two potential non invasive approaches involve the analysis of fetal cells and cell-free fetal DNA (cffDNA) found in the maternal circulation. The presence of fetal cells in the maternal circulation was first documented by 1893 when the fetal cells were found in pregnant women died for eclampsia. The Fetal erythroblasts (NRBC) from the maternal circulation have been considered the best potential target for NIPD because they can be detected early in pregnancy, are nucleated and have short life. The NRBC isolation from maternal circulation is still
difficult because the number of NRBC is small and a fetal specific antibody is not currently available. Cff-DNA detected in the maternal circulation during pregnancy, could potentially offer an excellent method for early NIPD of the genetic status of a fetus. In a recent study has been
shown that, during the pregnancy, the cffDNA is cleared from the maternal circulation, 16 min following delivery. Moreover, it has been demonstrated that cffDNA has a mean
fractional concentration of about 10%. The goal of our project was to develop and validate a protocol for NIPD of monogenic diseases by two experimental procedures: the isolation and the molecular characterization of fetal NRBC, and the analysis of cffDNA in maternal plasma. We recruited 95 pregnant women between 6th and 14th week of gestation. In our study we have developed a protocol for fetal NRBC isolation from maternal blood that unfortunately require further refinements the isolation procedure. In parallel we have developed a protocol for non invasive fetal sexing from cffDNA. This method appears to be highly accurate showing 100% sensitivity and 96% specificity. In the next future we are planning to analyze cffDNA both for monogenic diseases and for the most frequent aneuploidies using massively parallel sequencing
Dominant points detection for shape analysis
Get PDFThe growing interest in recent years towards the multimedia and the large amount of information exchanged across the network involves the various fields of research towards the study of methods for automatic identification. One of
the main objectives is to associate the information content of images, using techniques for identifying composing objects. Among image descriptors, contours reveal are very important because most of the information can be extracted
from them and the contour analysis offers a lower computational complexity also. The contour analysis can be restricted to the study of some salient points with high curvature from which it is possible to reconstruct the original contour. The thesis is focused on the polygonal approximation of closed digital curves. After an overview of the most common shape descriptors, distinguished between
simple descriptors and external methods, that focus on the analysis of boundary points of objects, and internal methods, which use the pixels inside the object also, a description of the major methods regarding the extraction of dominant points studied so far and the metrics typically used to evaluate the goodness of the polygonal approximation found is given. Three novel approaches to the
problem are then discussed in detail: a fast iterative method (DPIL), more suitable for realtime processing, and two metaheuristics methods (GAPA, ACOPA) based on genetic algorithms and Ant Colony Optimization (ACO), more com-
plex from the point of view of the calculation, but more precise. Such techniques are then compared with the other main methods cited in literature, in order to
assess the performance in terms of computational complexity and polygonal approximation error, and measured between them, in order to evaluate the robustness with respect to affine transformations and conditions of noise. Two
new techniques of shape matching, i.e. identification of objects belonging to the same class in a database of images, are then described. The first one is based on the shape alignment and the second is based on a correspondence by ACO, which puts in evidence the excellent results, both in terms of computational time and recognition accuracy, obtained through the use of dominant points. In the first matching algorithm the results are compared with a selection of dominant points generated by a human operator while in the second the dominant points are used instead of a constant sampling of the outline typically used for
this kind of approach
Attivazione del gene delta globinico in vivo attraverso la creazione di topi transgenici quale modello di studio per la cura della beta talassemia
Get PDFThe δ globin gene is the minor adult β-like globin gene in humans. The δ globin chain forms together with the α globin chain, the hemoglobin A2 (HbA2). HbA2 represents less than 3% of the total hemoglobin in normal individuals and it is typically increased in β thalassemia carriers. The δ globin gene is highly homologous to the δ globin gene deriving from a common ancestor . In our previous work we ( as well as others) have demonstrated, in vitro, that the creation of the CACCC box consensus sequence on the globin gene promoter is sufficient to enhance its expression to a considerable extent. This observation is at the basis of possible gene therapy strategies for hemoglobinopathies based on the reactivation of the endogenous δ globin gene. The δ globin chain could represent in fact a valid substitution of the δ globin chain in beta thalassemia
patients. It is also well known that HbA2 is a powerful antisickling agent which could benefit sickle
cell patients. Here we show that:
1) The δ globin gene promoter can be activated in vivo in a transgenic mouse model;
2) The activated δ globin gene promoter is able to drive the expression of δ globin gene to a high
level;
3) The crossing of the homozygous transgenic line LCR-δ CACCC with the heterozygous mouse
model of β0-thalassemia (Hbbth-3/+) increased up to 3 g/dl the total hemoglobin level.
First, we have produced transgenic mice lines with a DNA construct in which the wild type (wt) β globin gene promoter and the proximal CACCC box containing δ globin gene promoter are linked in cis to a single erythroid specific enhancer, the second hypersensitive site ( HS2) of the Locus Control Region (LCR), (HS2δMFLβRL). The order of the different elements in our construct mimics the spatial organization of the βglobin cluster were the δ globin gene is situated 5’ to the β gene and relatively closer to the LCR. We have also produced transgenic mice lines bearing the wtδ globin gene promoter on place of the CACCC containing δ, as a control line (HS2δ wtFLβRL). The δ and β globin gene promoters are respectively linked to two different (fireflies and renilla) luciferase reporter genes. The level of the expression of the two reporter genes has been assessed in the fetal liver at day 10.5, 12.5, 14.5 and 16.5 post coitum (pc). We have analyzed 3 independent transgenic lines bearing the CACCC containing δ globin gene promoter construct(HS2δ FLβ RL), and 3 independent lines bearing the control construct (HS2δwtFLβ RL). For each transgenic line we have analyzed 3 different pregnancies. Fetal liver samples have been lysated and the crude protein extracted has been assayed for the luciferase versus renilla activity. The expression level of the transgenic lines bearing the construct with the CACCC box containing δ globin gene promoter (HS2δ FLRβ L) show an activity greater than the control wt (HS2δ wtFLβ RL): 12.5pc (85.07%±15,8 – t test 1.57164E-06), 14.5pc (78,74%±22,6 – t test 0.0002) e 16.5pc (97,35%±29,3 – t test 0.0006. After these preliminary results, we have produced a transgenic line carrying the mini LCR (HS-
HS4) and the δ gene driven by the CACCC containing δ promoter (CACCCδM-LCR). Here we show that the δ globin gene can be activated in vivo reaching high levels of expression in our transgenic mouse model. Our results on a single copy transgenic line show an expression level of the δ gene of 30% compared to the endogenous beta major.
This level of expression could be considered curative for beta thalassemia and sickle cell disease. After this result, we decided to intercross the homozygous transgenic line CACCCδM-LCR with the heterozygous mouse model of beta-thalassemia (Hbb-th3/+). Hematological analysis performed at 8 weeks after-born mice Hbb-th3/+ revealed 8,7±1,2 g/dL of total hemoglobin levels versus 10,5 g/dL ± 1,3 in heterozygous CACCCδM-LCR /Hbb-th3/+ mice, 11,6±0,94 g/dL in homozygous CACCCδM-LCR /Hbb-th3/+ and 15.48±1.4 g/dL in wild type mice. We plan to obtain the final validation of the δ globin gene as a therapeutic gene by the rescue of the thalassemic mouse model th3/th3. Current gene therapy strategies for the hemoglobinopathies
focus on the trasduction of the hematopoietic stem cells by viral vectors. More recently strategies involving the correction of the endogenous δ globin gene by homologous recombination have been proposed. An alternative approach could be to introduce into the hematopoietic stem cells an engineered transcription factor able to enhance δ globin gene transcription. Recently enormous developments have been made in engineering sequence specific zinc finger DNA-binding protein. It is thus conceivable to design a
δ specific transcription factor able to specifically activate the endogenous δ globin gene as a therapeuthical tool for the hemoglobinopathies
Il trattamento cronico con etinilestradiolo e levonorgestrel modifica i livelli cerebrali dei neurosteroidi e il comportamento nel ratto
Get PDFOral contraceptives (OCs) are among the most widely used drugs in the world and offer many benefits for women's health, such as reduction of the risk of endometrial and ovarian cancer, benign ovarian cysts, and are useful in the control of menstrual irregularities and acne. However, several studies show that OCs induce adverse effects in the central nervous system, such as mood disorders, irritability and decreased sexual desire. We have previously demonstrated that long-term treatment
with a combination of ethinylestradiol and levonorgestrel (EE/LNG), two of the compounds more frequently used in OCs in female rats decreases brain concentrations of progesterone and its metabolite allopregnanolone, a positive allosteric modulator of the type A receptor for the gamma-aminobutyric acid (GABA), the most common inhibitory neurotransmitter of the central nervous
system, which exerts anxiolytic, anticonvulsant, sedative-hypnotics and neuroprotective effects and is involved in the regulation of social and sexual behavior in female rats. The aim of this research was to assess whether the reduction in the brain concentrations of allopregnanolone induced by EE/LNG treatment altered the behavior of rats. Chronic treatment with EE/LNG induces an anxiety-like behavior in animals, reduces agonistic behavior and sexual motivation, while it does not affect cognitive functions, such as learning and spatial memory. Accordingly, the recovery of allopregnanolone concentration induced by progesterone administration results in a significant
increase in sexual motivation, while the subsequent blocking of its synthesis by finasteride decreases proceptive behaviors. These results suggest that the reduction in allopregnanolone concentrations induced by OCs treatment might be relevant to the side effect sometimes exhibited by women taking these drugs
Modeling and Performance Evaluation of MANET Handover
Get PDFA Mobile Ad Hoc Network (MANET) is an unstructured collection of wireless nodes that move arbitrarily and use multi-hop protocols to communicate between each other. There is not a predefined infrastructure in a MANET as there is in other types of wireless networks. Now days,
MANET networks integrate with other networks, like the Internet, permitting ad hoc nodes to communicate with hosts placed in any part of the world. But the integration of MANETs with fixed infrastructures must be carefully studied to evaluate how it performs. In such integrated scenario,
commonly known as Hybrid Ad Hoc Network, a MANET can be seen as an extension to the existing infrastructure, whose mobile nodes seamlessly communicate with hosts on the fixed network by forwarding packets throughout the gateways found on the edge that join both types of network. Connecting MANETs to the Internet does not come without difficulties. Ad hoc routing protocols work different than the regular routing protocols used on the Internet, and their
interoperability becomes an important issue. But when MANETs integrate with the Internet, a more demanding challenge emerges if node mobility is considered. A moving node may lose registration with its current gateway, and may then need to register to a different gateway (a handover) to continue communicating. During a handover, any ongoing communication will be interrupted affecting network performance. In order to improve this performance, an IP mobility management protocol must be used. The main objective of this research is to develop a model that may be used to evaluate the performance of MANET handovers under different scenarios. Different issues about MANET
integration with the Internet are considered: the IP mobility protocol implemented, the external route computation procedure, the type of ad hoc routing protocol used, and the gateway discovery approach used. For this evaluation, a mobile node in a MANET holding a communication with a correspondent node in the Internet roams to a different sub-network, having to change its
registration to a different gateway. The different scenarios considered to evaluate the handover
performance include the use of different types of MANET protocols, the use of different gateway discovery approaches, and the use of different versions of the Mobile IP protocol. During the research a review was made of the functioning conditions for the proposed scenario. Then, a handover model was proposed, which was used to develop some metrics that were later used to evaluate the MANET handover performance. This metrics are the broken communication time, the probability of handover failure, and the average communication interruption time. In all the results found, we could confirm that the proactive discovery approach
has a better handover performance than the reactive discovery approach, which permit us to conclude that regardless the MANET routing protocol, and the Mobile IP version, the proactive agent discovery approach should be used in highly mobile scenarios, preferable, with the reactive routing protocol
Studio preliminare per la valutazione della fattibilità di un progetto di CO2-ECBM nel bacino carbonifero del Sulcis
Get PDFNowadays CO2 geological storage represents a valuable alternative to reduce greenhouse gases release into atmosphere. Correct identification of the location for a suitable reservoir is a complex decisional process
because it must consider a great number of criteria mainly concerning environmental, geological and economical aspects. The variety and variability of these parameters make each evaluation unique and, for this reason, it is not advisable for the decision maker (DM) using only his own
experience rather it would be advisable the use of a decision support system (DSS). In the carbon sequestration research field, the combination of DSS and GIS technologies allows the realization of powerful tools able to identify and solve technical problems and to evaluate both technically and economically different alternatives in order to assure the right balance between the success of the project and its environmental sustainability.
The main objective of this research work was to propose a novel approach for the assessment of the pre-feasibility of a CO2 geological storage within Sulcis Coal Basin coal seams (Italy, SW Sardinia) with enhanced coalbed methane recovery (ECBM). All the techniques developed to assess suitable reservoirs, to perform the in-situ characterization and to evaluate “Sulcis” coal required a complex of studies and laboratory tests. All methods and results are introduced and discussed within this PhD thesis
Modelli letterari russo-sovietici del romanzo neorealista: Pavese, Calvino e Viganò (1938-1949)
Get PDFThis thesis is about the role of Soviet-Russian literature in translation as a model for the literary evolution of Neorealist novel. The first part analyzes the conflicting reception of Soviet-Russian culture and literature in pre-fascist and fascist Italy, trying to underline the alternative reception of Russian revolutionary culture and literature expressed by Gobetti, Ginzburg and Gramsci. The second part illustrates the suggestions of Soviet-Russian literature that can be found in the developing literary activity of Cesare Pavese and discusses in detail the role of some Soviet-Russian literary models (I. Goncharov’s Oblomov, A. Fadeev’s The Rout, M. Sholokhov’s Virgin Soil Upturned) for the composition of four of his most important novels: Il carcere, Paesi tuoi, Il compagno, La casa in collina. The third and the fourth part study the role of some Soviet-Russian literary models (L. Tolstoy’s War and Peace, M. Gorky’s Mother, A. Fadeev’s The Rout, M. Sholokhov’s Virgin Soil Upturned, N. Ostrovsky’s How the Steel Was Tempered, K. Simonov’s Days and Nights) for the composition of two Resistance novels: Il sentiero dei nidi di ragno by Italo Calvino and L’Agnese va a morire by Renata Viganò
Security of multimodal biometric systems against spoof attacks
Get PDFA biometric system is essentially a pattern recognition system being used in ad-versarial environment. Since, biometric system like any conventional security system is exposed to malicious adversaries, who can manipulate data to make the system ineffective by compromising its integrity. Current theory and de- sign methods of biometric systems do not take into account the vulnerability to such adversary attacks. Therefore, evaluation of classical design methods is an open problem to investigate whether they lead to design secure systems. In order to make biometric systems secure it is necessary to understand and evalu-ate the threats and to thus develop effective countermeasures and robust system designs, both technical and procedural, if necessary. Accordingly, the extension
of theory and design methods of biometric systems is mandatory to safeguard the security and reliability of biometric systems in adversarial environments. In
this thesis, we provide some contributions towards this direction. Among all the potential attacks discussed in the literature, spoof attacks are one of the main threats against the security of biometric systems for identity
recognition. Multimodal biometric systems are commonly believed to be in-trinsically more robust to spoof attacks than systems based on a single biomet-ric trait, as they combine information coming from different biometric traits.
However, recent works have question such belief and shown that multimodal systems can be misled by an attacker (impostor) even by spoofing only one of the biometric traits. Therefore, we first provide a detailed review of state-of-the-art works in multimodal biometric systems against spoof attacks. The scope ofstate-of-the-art results is very limited, since they were obtained under a very
restrictive “worst-case” hypothesis, where the attacker is assumed to be able to fabricate a perfect replica of a biometric trait whose matching score distribu-tion is identical to the one of genuine traits. Thus, we argue and investigate the validity of “worst-case” hypothesis using large set of real spoof attacks and provide empirical evidence that “worst-case” scenario can not be representa-
ixtive of real spoof attacks: its suitability may depend on the specific biometric trait, the matching algorithm, and the techniques used to counterfeit the spoofed traits. Then, we propose a security evaluation methodology of biometric systems against spoof attacks that can be used in real applications, as it does not require fabricating fake biometric traits, it allows the designer to take into account the different possible qualities of fake traits used by different attackers, and it exploits only information on genuine and impostor samples which is col-
lected for the training of a biometric system. Our methodology evaluates the performances under a simulated spoof attack using model of the fake score distribution that takes into account explicitly different degrees of the quality of fake biometric traits. In particular, we propose two models of the match score distribution of fake traits that take into account all different factors which can affect the match score distribution of fake traits like the particular spoofed biometric, the sensor, the algorithm for matching score computation, the technique used to construct fake biometrics, and the skills of the attacker. All these factors are summarized in a single parameter, that we call “attack strength”. Further, we propose extension of our security evaluation method to rank several biometric
score fusion rules according to their relative robustness against spoof attacks. This method allows the designer to choose the most robust rule according to the method prediction. We then present empirical analysis, using data sets of face and fingerprints including real spoofed traits, to show that our proposed models provide a good approximation of fake traits’ score distribution and our
method thus providing an adequate estimation of the security1 of biometric systems against spoof attacks. We also use our method to show how to evaluate the security of different multimodal systems on publicly available benchmark
data sets without spoof attacks. Our experimental results show that robustness of multimodal biometric systems to spoof attacks strongly depends on the particular matching algorithm, the score fusion rule, and the attack strength of fake traits. We eventually present evidence, considering a multimodal system based on face and fingerprint biometrics, that the proposed methodology to rank score
fusion rules is capable of providing correct ranking of score fusion rules under spoof attacks
Perception and Motion: use of Computer Vision to solve Geometry Processing problems
Get PDFComputer vision and geometry processing are often see as two different and, in a certain sense, distant fields: the first one works on two-dimensional data, while the other needs three dimensional information. But are 2D and 3D data really disconnected? Think about the human vision: each eye captures patterns of light, that are then used by the brain in order to reconstruct the perception of the observed scene. In a similar way, if the eye detects a variation in the patterns of light, we are able to understand that the scene is not static; therefore, we're able to perceive the motion of one or more object in the scene. In this work, we'll show how the perception of the 2D motion can be used in order to solve two significant problems, both dealing with three-dimensional data. In the first part, we'll show how the so-called optical flow, representing the observed motion, can be used to estimate the alignment error of a set of digital cameras looking to the same object. In the second part, we'll see how the detected 2D motion of an object can be used to better understand its underlying geometric structure by means of detecting its rigid parts and the way they are connected