Microfluidic modules for pre-concentration of [¹⁸F]fluoride in positron emission tomography (PET) radiotracer synthesis

lPositron Emission Tomography (PET) is a non-invasive imaging method which enables to obtain both molecular and biochemical information of physiological processes in vivo, which means that PET imaging shows the chemical functioning of organs and tissues in a living subject. In recent years microfluidic lab-on-a-chip devices have been explored as a promising alternative for radiotracer synthesis due to benefits such as (i) superior control over reaction conditions leading to high yields and conversion rates, (ii) reduced reagent consumption and radioactive waste production as well as (iii) potential for automation with minimised shielding requirement. That said, most devices presented so far have focused on the synthesis of the radiotracer, with relatively little emphasis on the integrated devices that perform activation, synthesis and purification steps in an automated fashion. FDG (fluorodeoxyglucose) is one of the most widely used radiopharmaceuticals in Positron Emission Tomography (PET). Moreover the availability of several other PET radionuclides makes fluorine-18 (¹⁸F) the most predominant in the fields of oncology and neuroscience. The aim of the Radiochemistry On Chip (ROC) project was to develop such an integrated lab-on-chip device and, in particular, here results for on-chip pre-concentration of fluoride, together with some preliminary results on the removal of Kryptofix (K2.2.2) and the purification of fluoroethyl-dimethyl-2-hydroxy-ethylammonium (FECH) are presented. Here in, three microfluidic modules for fluoride pre-concentration are described, the first employs a dam structure, the second and the third magnetic forces. In the final part of the thesis, preliminary results on the purification of fluoroethylcholine (FECH) and a suitable detection method for Kryptofix (K2.2.2) are reported. Firstly, the design, fabrication and implementation of a glass microfluidic device for recovery of [¹⁸F] and [¹⁹F]fluoride ions is described. The device was initially tested with non radioactive [¹⁹F]fluoride ions and shown to repeatedly trap and elute > 95% fluoride over 40 successive experimental runs with no decrease in efficiency. The same device was then tested for the trapping and release of [18F]fluoride ions, again over 20 experiments were executed with no measurable decrease in performance. Finally, the [¹⁸F]fluoride ions were eluted as a K¹⁸F/K2.2.2 complex, dried by repeated dissolution in acetonitrile and evaporation of residual water, and reacted with EtDT leading to the formation of the desired product ([¹⁸F]fluoroethyltosylate) with 96 ± 3 % yield (RCY). The overall time needed for conditioning, trapping, elution and regeneration was less than 6 minutes. This approach will be of great benefit towards an integrated platform able to perform faster and safer radiochemical synthesis on the micro-scale. In the following chapter, magnetic microparticles are described as a method for the trapping and elution of [¹⁸/¹⁹F]fluoride ions via formation of a magnetic plug inside a glass microdevice. Even though the method was found to be not as fast and efficient as the packed bed of microparticles (Chapter 3), and still requires several manual steps which are time and labour consuming, the proof of principle illustrates an alternative process not yet reported in the literature, with potential for future on-chip pre-concentration of fluoride. The results showed that by employing positively charged magnetic particles, fluoride could be trapped in yield of > 50 % and elution achieved with approximately 90 % recovery of fluoride. A subsequent method for reducing the inefficiencies of the plug of magnetic particles is described where a multilaminar flow microreactor was investigated in which functionalised magnetic particles can be deflecte

Large Pseudo-Counts and L2L_2-Norm Penalties Are Necessary for the Mean-Field Inference of Ising and Potts Models

Mean field (MF) approximation offers a simple, fast way to infer direct interactions between elements in a network of correlated variables, a common, computationally challenging problem with practical applications in fields ranging from physics and biology to the social sciences. However, MF methods achieve their best performance with strong regularization, well beyond Bayesian expectations, an empirical fact that is poorly understood. In this work, we study the influence of pseudo-count and $L_2$-norm regularization schemes on the quality of inferred Ising or Potts interaction networks from correlation data within the MF approximation. We argue, based on the analysis of small systems, that the optimal value of the regularization strength remains finite even if the sampling noise tends to zero, in order to correct for systematic biases introduced by the MF approximation. Our claim is corroborated by extensive numerical studies of diverse model systems and by the analytical study of the $m$-component spin model, for large but finite $m$. Additionally we find that pseudo-count regularization is robust against sampling noise, and often outperforms $L_2$-norm regularization, particularly when the underlying network of interactions is strongly heterogeneous. Much better performances are generally obtained for the Ising model than for the Potts model, for which only couplings incoming onto medium-frequency symbols are reliably inferred.Comment: 25 pages, 17 figure

Study of responses to heat stress in durum wheat, and their relationship with nutraceutical quality

Il frumento duro [Triticum turgidum (L.) subsp. turgidum (L.) convar. durum (Desf.)] è una coltura di largo uso per la nutrizione umana, in particolare nel bacino del Mediterraneo. Costituisce la principale fonte di semola utilizzata per la produzione di pasta, pane di frumento duro, ma viene utilizzato anche per la produzione di cuscus e burghul. Condizioni ambientali avverse riducono la produzione e influenzano le caratteristiche qualitative della granella. Gli stress che più comunemente colpiscono le piante coltivate consistono in un eccesso o carenza di acqua, eccesso di sale o metalli pesanti nel terreno, e temperature estreme. In particolare dall’inizio del secolo si sta assistendo ad un incremento della temperatura media mondiale, ed un ulteriore aumento è previsto per i prossimi decenni. Alte temperature durante la fase riproduttiva del frumento possono determinare una riduzione del peso della granella e del numero di semi per spiga. Queste espressioni fenotipiche sono il risultato dell’alterazione del profilo dei trascritti e di variazione dei livelli di accumulo dei metaboliti nelle piante, in risposta ai cambiamenti di temperatura. Lo scopo di questa ricerca è di studiare le variazioni dei trascritti e dei metaboliti in risposta a stress termico, in due varietà di frumento duro, e di comprendere come tali variazioni possano influenzare la composizione della granella e quindi la qualità nutrizionale e nutraceutica del prodotto finale acquistato dai consumatori. Lo studio è stato condotto sulla varietà di frumento duro Primadur e su una cultivar non commercializzata T1303 (codice USDA PI 352395); la prima è una cultivar élite caratterizzata da alta resa produttiva e un alto indice di giallo (altamente correlato al contenuto di pigmenti carotenoidi), la seconda è una cultivar caratterizzata da un alto contenuto di antociani che conferiscono alla granella un colore rosso (purple-cultivar). Lo shock termico è stato imposto a 37°C, durante il periodo di riempimento della granella. La temperatura elevata è stata imposta per 5 giorni in un periodo che va dal quinto al decimo giorno dopo la fioritura. Le analisi sono state condotte su seme immaturo, prelevato 14 giorni dopo la fioritura, e seme maturo, prelevato alla fine del ciclo riproduttivo della pianta. I risultati ottenuti da seme derivante da piante sottoposte a shock termico sono stato confrontati con quelli ottenuti da piante controllo (20°C). La risposta allo stress è stata valutata con due differenti approcci. L’analisi dell’espressione genica, condotta con un approccio di sequenziamento genome–wide di nuova generazione che ha utilizzato la tecnologia Illumina, ha mostrato che un totale di 1202 geni hanno subito variazioni dei livelli di trascritto in risposta a stress. Molti dei geni sovraespressi in risposta a stress in Primadur ricadevano nelle categorie geniche note per avere un ruolo in risposta a stress, mentre tali categorie erano meno rappresentate in T1303 in cui erano sovraespressi geni codificanti per proteine di 3 riserva. Tali risultati erano in accordo con la maggiore sensibilità allo stress termico mostrata da Primadur rispetto a T1303, valutata come calo in peso della granella. L'accumulo dei metaboliti è stato valutato con gas-cromatografia associata a spettromeria di massa (GS-MS) in seme immaturo e maturo. I due genotipi hanno mostrato differente risposta allo stress termico. Il contenuto di molti dei metaboliti analizzati è risultato incrementato in ‘Primadur’, mentre un decremento è stato osservato in T1303; tuttavia per alcuni metaboliti con un ruolo chiave di risposta alle condizioni di stress (per esempio saccarosio e glicerolo) è stato osservato un incremento del contenuto per entrambi i genotipi. Per alcuni metaboliti le variazioni sono state osservate già nel seme immaturo e le stesse variazioni sono state conservate anche nel seme maturo. Questo studio ha evidenziato come un incremento di temperatura, della durata di pochi giorni nelle fasi iniziali di riempimento della granella, sia in grado di determinare cambiamenti a breve e lungo termine in grado di cambiare qualità e produzione della granella di frumento duro. In risposta a stress, il contenuto di antociani è risultato incrementato mentre quello dei carotenoidi non è variato. Solo lo sfarinato della granella di T1303, maturata dopo l’imposizione dello stress, ha mostrato un incremento della capacità antiossidante (misurata come ‘Trolox Equivalent Antioxidant Capacity’-TEAC) rispetto allo sfarinato della granella maturata in condizioni controllo. Il contenuto proteico è risultato incrementato solo in ‘T1303’, che ha mostrato un minore calo in peso della granella rispetto a Primadur, in risposta allo stress. Questo studio fornisce nuove conoscenze sugli effetti dell'adattamento allo stress termico del frumento duro sulle proprietà nutrizionali e qualitative della granella e mostra come tali proprietà possano essere differentemente alterate in due genotipi. Anche se il ‘background’ genetico dei due genotipi è differente, non può essere escluso che alcune delle differenze osservate, nella risposta a stress termico, tra i due genotipi possano essere legate al metabolismo degli antociani. L’incremento del loro accumulo in risposta a stress termico insieme al ridotto calo in peso della granella sono considerati tratti di interesse per le future attività di miglioramento genetico del frumento duro.Durum wheat [Triticum turgidum (L.) subsp. turgidum (L.) convar. durum (Desf.)] is an important crop for human nutrition, especially in the Mediterranean area, where it is the main source of semolina for the production of pasta, traditional/typical bread, couscous, and burghul. Environmental stress can strongly limit the yield potential and affect qualitative characteristics of grain. The stress conditions that are commonly experienced by crops are extreme lack or excess of water (i.e., drought, flooding), presence of salt or contaminants (e.g., heavy metals), and temperature (i.e., cold, heat). In particular, environmental temperatures have increased since the beginning of the last century and they are predicted to further increase under the present conditions of climate change. Wheat is very sensitive to high temperatures during the reproductive phase, due to direct effects of temperature on grain numbers and dry weight. These phenotypic effects are due to molecular modifications at the different levels of gene expression, and to changes in metabolite accumulation levels. The aim of this study was to investigate the transcriptomic and metabolomic variations in response to heat stress in grains of two durum wheat genotypes, and their relationship with variation in grain composition that can affect the nutraceutical quality of the final product. The study was carried out on the durum wheat cv Primadur and T1303 (PI 352395 USDA code); the first is an elite cultivar with high grain yield and yellow index and the second one an anthocyanin-rich purple cultivar. Heat shock was imposed at 37°C from 5 up to 10 days after flowering (DAF). Immature seeds (14 DAF) and mature seeds (seeds at physiological maturity stage), collected from heat shocked and control plants (20°C), were analyzed. The response to stress was investigated with different approaches. Genome–wide gene expression analysis, carried out using Illumina HiSeq2000, showed that 1202 genes were differentially expressed in response to stress in the two genotypes. The number of up-regulated genes belonging to stress-related categories was higher in Primadur with respect to T1303, whereas the number of genes with nutrient reservoir activity was larger in T1303 compared to Primadur. These results were according to the higher sensitivity to stress of Primadur with respect to T1303, measured as grain weight loss. The profile of polar metabolites was investigated by gas chromatography-mass spectrometry (GC-MS). The effects of heat stress were genotype dependent. Although some metabolites (e.g., sucrose, glycerol) increased in response to heat stress in both genotypes, clear differences were observed. Following the heat stress, there was a general increase in most of the analyzed metabolites in Primadur, with a general decrease in T1303. Heat shock applied early during seed development produced changes that were observed in immature seeds, and also long-term effects 5 that changed the qualitative and quantitative parameters of the mature grain. The level of anthocyanins increased significantly in response to the heat stress whereas the levels of carotenoids were not affected. Only for T1303, the Trolox equivalent antioxidant capacity (TEAC) method assessed an increased antioxidant capacity of ground grains, in response to heat stress. Protein content increased only in T1303 that showed lower grain weight loss with respect to Primadur, in response to stress. Therefore, short heat-stress treatments can affect the nutritional and nutraceutical value of grain of different genotypes of durum-wheat in different ways. The present study increased the knowledge about the effect of mechanisms of adaptation to stress of wheat plants on nutritional and quality traits of grain and provides a global picture of the effects of the heat stress on metabolies and transcriptome of two different genotypes of durum wheat. Moreover, although the genetic backgrounds of two durum-wheat genotypes were different, it cannot be excluded that some of the differences observed in the responses to heat stress can be due to anthocyanin accumulation, which can be considered a trait of interest for future breeding activities for durum wheat

Forme organizzative del terzo settore e qualità sociale

Il dibattito scientifico e culturale che si è sviluppato anche in Italia a partire dalla metà degli anni ’80 sul terzo settore, le sue caratteristiche, il suo ruolo economico e sociale, ha prodotto una grande quantità di ricerche, riflessioni teoriche e proposte politiche. Il terzo settore è diventato per sociologi, analisti delle politiche pubbliche ed economisti un osservatorio privilegiato per analizzare le trasformazioni degli obiettivi e delle forme di regolazione delle politiche sociali, in rapporto anche alle metamorfosi del lavoro e della struttura produttiva. Pur nella eterogeneità e relativa incoerenza che caratterizzano questo campo di studi, in termini di definizioni e classificazioni, di frames interpretativi e di intenzioni politiche sottese 1, vi è in generale un consenso di fondo nel considerare strategico il ruolo del 3° settore nella riorganizzazione dei sistemi di welfare, in particolare rispetto all’obiettivo di ricostituire sinergie rinnovate tra sviluppo economico e benessere sociale (...)

EFFECTS OF A PLYOMETRIC SUPPLEMENTAL TRAINING ON VERTICAL JUMP HEIGHT AND AESTHETIC JUMPING ABILITY IN ADOLESCENT FEMALE DANCERS

Dance is an artistic discipline that requires precision, artistry, grace, strength and power. Previous studies indicate that plyometric training has positive effects on fitness performance measures in ballet and modern dancers. However, many dancers are wary of engaging in supplementary training out of fear of excessive muscle hypertrophy that could change the aesthetics of body appearance, technique and general, dance artistry. Therefore, the purpose of this study was to investigate the effects of an 8-week supplementary plyometric intervention on vertical jump height, aesthetic jumping ability and anthropometric measures in female contemporary dancers. Sixteen females (12-18 years) were randomly assigned to an 8-week experimental group (EG, n=8) that performed a supplementary plyometric training twice a week or a control group (CG, n=8) that continued regular dance regimen. At baseline and after 8 weeks all participants were tested on the subjective aesthetic jumping ability, anthropometrics and vertical jump. The EG group showed significant (p<0.05) improvements in the subjective ability to hang suspended in the air during a jump (+21.4%) and the subjective jump height (+43.3%) following the intervention. Also, a significant ‘Time x Group’ interaction was found for countermovement jump and countermovement jump free arms (p<0.05), with the EG that showed significant improvements of 36.8% and 47.9%, respectively. No significant changes were seen in the CG for all measures from pre- to post-testing. There were no significant changes in any group for body weight and body fat. Our findings suggested that an 8-week supplementary plyometric training program twice a week had a significantly beneficial effect on both physical fitness indices and aesthetic jumping ability for female contemporary dancers. Therefore, it is suggested that the way a dancer is trained needs to be reviewed and the concept of supplementary training must be deepened.  Article visualizations

Les cooperatives sociales et la construction du tiers secteur en Italie

La notion de tiers secteur s’est imposée en Italie à la fin des années quatre-vingt, au moment où les organisations et les pratiques de l’économie sociale ont été identifiées et valorisées. Il s’agit d’une définition par défaut d’un espace qui ne relève ni de l’État, ni du marché. C’est peut-être précisément pour cela qu’il a pu, parfois par la contrainte, inclure des pratiques et des organisations hétérogènes sous bien des aspects. Il s’agissait essentiellement au début d’un contre-discours sur l’État-providence selon lequel il fallait « dépasser » aussi bien la solution autoritaire d’une « société totalement administrée » (de type collectiviste, mais également sociale-démocrate), que la solution néolibérale de la mise en liquidation des institutions de protection sociale, grâce à la contribution décisive des ressources du volontariat et à la capacité d’initiative de la société civile (...)