Development of Solid-Phase Extraction Using Molecularly Imprinted Polymer for the Analysis of Organophosphorus Pesticides-(Chlorpyrifos) in Aqueous Solution

A new and selective sorbent for molecularly imprinted solid-phase extraction (MISPE) was prepared to extract chlorpyrifos (CPF) residue from solutions. The extracted analyte was analyzed by high performance liquid chromotography (HPLC) coupled with photodiode array detection. To synthesize the molecularly imprinted polymers, four different pyrogens (acetonitrile, toluene, dichloromethane and chloroform) were initially studied. CPF was used as the template molecule, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinker. Thermo-polymerization method was used to produce bulk polymers. In order to determine the medium that enhances the best molecular recognition, the adsorption study of CPF to the MIPs was investigated. Both organic solvents and water were utilized as media. The acetonitrile solvent was fnally selected as pyrogen for the synthesisof the polymers and water was chosen as the medium for loading the analytes into the polymers. The selectivity of the MISPE method for CPF and other pesticides in aqueous solution was also assessed

Selection of imprinted nanoparticles by affinity chromatography

Soluble molecularly imprinted nanoparticles were synthesised via iniferter initiated polymerisation and separated by size via gel permeation chromatography. Subsequent fractionation of these particles by affinity chromatography allowed the separation of high affinity fractions from the mixture of nanoparticles. Fractions selected this way possess affinity similar to that of natural antibodies (Kd 6.6 × 10−8) M and were also able to discriminate between related functional analogues of the templ

Direct replacement of antibodies with molecularly imprinted polymer (MIP) nanoparticles in ELISA - development of a novel assay for vancomycin

A simple and straightforward technique for coating microplate wells with molecularly imprinted polymer nanoparticles (nanoMIPs) to develop ELISA type assays is presented here for the first time. NanoMIPs were synthesized by a solid phase approach with immobilized vancomycin (template) and characterized using Biacore 3000, dynamic light scattering and electron microscopy. Immobilization, blocking and washing conditions were optimized in microplate format. The detection of vancomycin was achieved in competitive binding experiments with a HRP-vancomycin conjugate. The assay was capable of measuring vancomycin in buffer and in blood plasma within the range 0.001-70 nM with a detection limit of 0.0025 nM (2.5 pM). The sensitivity of the assay was three orders of magnitude better than a previously described ELISA based on antibodies. In these experiments nanoMIPs have shown high affinity and minimal interference from blood plasma components. Immobilized nanoMIPs were stored for 1 month at room temperature without any detrimental effects to their binding properties. The high affinity of nanoMIPs and the lack of a requirement for cold chain logistics make them an attractive alternative to traditional antibodies used in ELIS

The stabilisation of receptor structure in low cross-linked MIPs by an immobilised template

In molecularly imprinted polymers (MIPs) a high level of cross-linking is usually important for preserving the receptor structure. We propose here an alternative approach for stabilising binding sites, which involves the use of an immobilised template. The idea is based on the assumption that an immobilised template will ‘‘hold’’ polymeric chains and complementary functionalities together, preventing the collapsing of the binding sites. To test this postulate, a range of polymers was prepared using polymerisable (2,4-diamino-6- (methacryloyloxy)ethyl-1,3,5-triazine) and non-polymerisable (or extractable) (2,4-diamino-6-methyl-1,3,5-triazine) templates, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. The level of cross- linking was varied from 12 to 80%. Polymerisations were performed in acetonitrile using UV initiation. Binding properties of the synthesised materials were characterised both by HPLC and equilibrium batch binding experiments followed by HPLC-MS or UV-visible detection. The adsorption isotherms of polymers were obtained and fitted to the Langmuir model to calculate dissociation constant, Kd, and concentration of binding sites for each material. The results strongly indicate that the presence of an immobilised template improves the affinity of MIPs containing low percentages of cross- linker. The low cross-linked MIPs synthesised with a polymerisable template also retain a reasonable degree of selectivity. Low crosslinked MIPs with such binding characteristics would be useful for the creation of new types of optical and electrochemical sensors, where induced fit or the ‘‘gate effect’’ could be used more effectively for generating and enhancin

Sensitivity analysis and applicability domain of the Keplerian map approach and application to distant retrograde orbits design

LAUREA MAGISTRALEModellare in modo efficace e allo stesso tempo accurato l'effetto di un secondo corpo sulla dinamica di uno spacecraft che sta orbitando attorno ad un attrattore primario, è stata da sempre una sfida. Le equazioni del problema dei tre corpi ristretto riescono in ciò, ma richiedono di essere integrate numericamente, non avendo una soluzione in forma chiusa. Questa integrazione numerica risulta essere dispendiosa in termini di tempo computazionale quando il moto del satellite deve essere predetto per un lungo periodo. Negli ultimi anni, la teoria della Keplerian Map è stata sviluppata con l'intenzione di approssimare con buona accuratezza la soluzione di queste equazioni in modo da risparmiare tempo nell'integrazione, essendo un modello (semi-)analitico. Implementata per la prima volta da Petrosky e Broucke nel 1988, l'ultima evoluzione della teoria include nel suo modello matematico il moto eccentrico del terzo corpo, ed è ottenuta senza fare assunzioni sul parametro di massa del sistema. Questo approccio è stato utilizzato per propagare il moto di un corpo in diversi scenari, come nel sistema Gioviano o per un asteroide vicino alla Terra. Ad ogni modo, non è ancora chiaro quando è possibile o no approssimare la traiettiera con buona accuratezza. In modo tale da sapere a priori se la Keplerian Map può essere utilizzata senza introdurre errori significanti, c'è la necessità di identificare un suo dominio di applicabilità. Questa regione può essere trovata comparando i risultati con quelli numerici proposti dal problema dei tre corpi. L'obiettivo di questa tesi è di determinare il dominio di applicabilità della Keplerian Map. Tale scopo è raggiunto tramite un'analisi di sensibilità nel quale le condizioni iniziali della particella sono fatte variare e poi propagate. Questa procedura è effettuata molte volte, comparando i risultati con quelli del problema dei tre corpi tramite un errore relativo. L'output sono diversi grafici nei quali è riportato il valore dell'errore in funzione di alcuni parametri del sistema, dai quali è possibile identificare quando le soluzioni convergono. Infine, dopo che un dominio di applicabilità è stato definito, la teoria viene applicata per progettare orbite retrogradi distanti, sfruttando un processo di ottimizzazione ed evidenziando i vantaggi nel fare ciò con la Keplerian Map. Questo lavoro di tesi è parte del progetto COMPASS "Control for Orbit manoeuvring through perturbations for application to space systems". Il progetto COMPASS ha ricevuto fondi dall'European Research Council (ERC) per il programma di ricerca e innovazione dell'European Union's Horizon 2020 (accordo di sovvenzione No 679086 - COMPASS).The effect of a secondary attractor on the dynamics of a spacecraft orbiting around a primary, has been always a challenge to be modeled in an efficient and, at the same time, accurate way. The equations of the Restricted Three Body Problem accomplish this task, but they require to be numerically integrated since they do not have a close form solution. Such numerical integration results to be expensive in terms of computational time when the motion of the probe shall be predicted for a long period. In recent years, the Keplerian Map theory was developed with the purpose of approximating the solution of such equations saving time and with good accuracy, possibly with a (semi-)analytical model. Implemented for the first time by Petrosky and Broucke in 1988, the latest evolution of the theory includes in its mathematical model the eccentric motion of the third body and it is obtained without making assumptions on the mass parameter of the system. The approach was applied to propagate the motion of a body in different scenarios, as in the Jovian system or for a Near Earth Asteroid. However, it is still not clear when it is possible or not to approximate the trajectory with good accuracy. In order to know a priori if the Keplerian Map approach can be used without introducing a significant error on the motion prediction, there is the necessity to identify an applicability domain. This region can be identified through a comparison with the solution obtained with the numerical integration of the three-body problem equations. The aim of this thesis is to determine the Keplerian Map applicability domain. Such purpose is achieved with a sensitivity analysis in which the initial conditions of the spacecraft are made to vary and then propagated. This procedure is performed many times comparing the results with the solution of the three-body problem through a relative percentage error. The output of this analysis are different plots in which the error value is reported in function of some system parameters. By reading these maps graphically, scenarios in which the theory can be applied are recognised. Finally, after that an applicability domain is defined, the theory is applied to design direct retrograde orbits with the exploitation of an optimisation process, highlighting the advantages in doing that with the Keplerian Map approach. This thesis project is part of the project COMPASS "Control for Orbit manoeuvring through perturbations for application to space systems". The COMPASS project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 679086 - COMPASS)

Bifurcation analysis of auction mechanisms

LAUREA MAGISTRALEQuello dei meccanismi economici è uno dei campi attualmente studiati della comunità scientifica. Abbiamo applicato strumenti della teoria dei giochi algoritmica a problemi d'asta con l'obiettivo di progettare un meccanismo in grado di guidare il sistema verso uno stato con un Social Welfare migliore rispetto a quello dell'equilibrio di Nash. Abbiamo studiato ed analizzato i meccanismi della First Price, Generalized Second Price e della GSP ripetuta con budget fissato. Ogni giocatore che prende parte al meccanismo utilizza strategie adattive, comunemente dette di learning. Oggetto di studio sono state le dinamiche evolutive del Q-Learning, FAQ e Gradient Ascent. Per modellare le dinamiche di apprendimento e studiare la calibrazione dei parametri abbiamo utilizzato strumenti di teoria dei sistemi, mentre, per lo studio di biforcazione, abbiamo utilizzato MATCONT un tool di Matlab in grado di analizzare sistemi di equazioni dinamiche. Infine è stato progettato un meccanismo in grado di guidare il sistema verso uno stato con Social Welfare migliore rispetto a quello del Nash che non è raggiungibile nel caso di giocatori razionali.This thesis focuses on the field of algorithmic applied to problems of decision with opponents, commonly called algorithmic game theory. This field combines mathematical models, which describe situations of strategic interaction, with algorithmic tools, which allow to find solutions that prescribe to each player the best strategies to be implemented. Within this framework, a topic currently studied by the scientific community is the development of economic mechanisms when the players, who will take part in the mechanism, use adaptive strategies, commonly called learning strategies. For example, a typically used algorithm is Q-Learning. To design the best economic mechanism it is necessary to model the learning dynamics of the players and study the calibration of the parameters of the mechanism using system theory tools, such as bifurcation studies. The objective of this project is to study this type of problem in the context of the auction scenarios. In particular, online advertising auctions (used, for example, by Google, Microsoft, Amazon) have been analyzed

Estimation of the variance for different estimators of the change over time for overlapping samples

This work was inspired by the growing need to have a measure of the accuracy of the estimates produced within the short-term statistics in the Official Statistics. In particular, the aim of the work is to illustrate the methodology for the computation of the variance for the estimators currently used in the service turnover survey carried on by the Italian National Institute of Statistics, for the quarterly turnover growth rate estimation. While the calculation of the variance of the estimates produced for a given instant of time is now a good practice (also through the development of software packages), the same does not happen for the variation of two quantities over time. An estimator of variance must take into account of both the estimator and the sampling design (Wolter, K.M. (1985)). The greatest difficulty is that for many surveys, the samples for producing estimates in two different time are not independent each other, due to the rotation operations of the sample. In particular for business surveys, in order to take into account the birth-mortality of units in the population and changes in stratification variables (such as size category and type of economic activity), the sample is updated, and a part of the units is replaced with others. Moreover, many indicators are non-linear function of linear estimators (e.g. simple ratio, difference of ratios), therefore, to calculate their variance a first-order Taylor approximation can be used. Alternatively, balanced repeated replication (BRR) can be used. My methodological contribution is not only to suggest how to assess the variance of possible estimators of the turnover variation over time, but also to compare such estimators with respect to their variance to identify the best one. The performance of these estimators is assessed by a simulation study, which also has the aim of exploring under which conditions it is better to use all the observations or only the overlapping observations. The change estimators and the corresponding estimators of the variance are defined at stratum and estimation domain level and take into account the use of a stratified sampling design and the updating of the sample due to a replacement of some units and to a dynamic stratification of the population

Basi genetiche dell’adattamento alle basse pressioni di ossigeno in popolazioni di alta quota delle Ande peruviane.

High-altitude is the only environment colonized by modern humans where no behavioral buffering is available to face the peculiar and unavoidable stress: hypoxia. Life at low oxygen pressure needs specific biological adaptations to deliver enough oxygen to maintain aerobic metabolism. In the last decades many studies investigated the relationship between altitude and adaptive phenotypic traits, but to date no association between genetic variants and adaptive traits to hypoxia-related stress have been found in native American highlands. Here we aim at identifying the genetic bases of human adaptation to high altitude by studying the evolution of candidate genes and investigating their genetic variation in Andean native populations. The hypoxia inducible factors (HIF-

Metallic nano carrier complex targeting neuroendocrine prostate cancer

Poster presented at Cranfield University’s 2019 Manufacturing Doctoral Community event

Nanomaterial integration in micro LED technology: Enhancing efficiency and applications

The micro-light emitting diode (µLED) technology is poised to revolutionise display applications through the introduction of nanomaterials and Group III-nitride nanostructures. This review charts state-of-the-art in this important area of micro-LEDs by highlighting their key roles, progress and concerns. The review encompasses details from various types of nanomaterials to the complexity of gallium nitride (GaN) and III nitride nanostructures. The necessity to integrate nanomaterials with III-nitride structures to create effective displays that could disrupt industries was emphasised in this review. Commercialisation challenges and the economic enhancement of micro-LED integration into display applications using monolithic integrated devices have also been discussed. Furthermore, different approaches in micro-LED development are discussed from top-down and bottom-up approaches. The last part of the review focuses on nanomaterials employed in the production of micro-LED displays. It also highlights the combination of III-V LEDs with silicon LCDs and perovskite-based micro-LED displays. There is evidence that efficiency and performance have improved significantly since the inception of the use of nanomaterials in manufacturing these