A novel approach for the estimation of nanoparticle evaporation through the Method of Moments

In this article the results of the application of two numerical approaches - the Method of Moments and the nodal method - for the prediction of the evaporation phenomena in the synthesis of nanoparticles are presented and compared, in order to evaluate the limits of the moment methods and to determine the usability of the method in plasma environments (i.e. high temperatures and steep gradients). Furthermore, a new closure term is introduced in the Method of Moments, in order to consider the disappearance of the particles due to the evaporation process. The Nodal Method is used as a benchmark for the Method of Moments

Many-core Algorithms for Combinatorial Optimization

Combinatorial Optimization is becoming ever more crucial, in these days. From natural sciences to economics, passing through urban centers administration and personnel management, methodologies and algorithms with a strong theoretical background and a consolidated real-word effectiveness is more and more requested, in order to find, quickly, good solutions to complex strategical problems. Resource optimization is, nowadays, a fundamental ground for building the basements of successful projects. From the theoretical point of view, Combinatorial Optimization rests on stable and strong foundations, that allow researchers to face ever more challenging problems. However, from the application point of view, it seems that the rate of theoretical developments cannot cope with that enjoyed by modern hardware technologies, especially with reference to the one of processors industry. In this work we propose new parallel algorithms, designed for exploiting the new parallel architectures available on the market. We found that, exposing the inherent parallelism of some resolution techniques (like Dynamic Programming), the computational benefits are remarkable, lowering the execution times by more than an order of magnitude, and allowing to address instances with dimensions not possible before. We approached four Combinatorial Optimization’s notable problems: Packing Problem, Vehicle Routing Problem, Single Source Shortest Path Problem and a Network Design problem. For each of these problems we propose a collection of effective parallel solution algorithms, either for solving the full problem (Guillotine Cuts and SSSPP) or for enhancing a fundamental part of the solution method (VRP and ND). We endorse our claim by presenting computational results for all problems, either on standard benchmarks from the literature or, when possible, on data from real-world applications, where speed-ups of one order of magnitude are usually attained, not uncommonly scaling up to 40 X factors

Intelligent approach to solvent substitution : the identification of a new class of levoglucosenone derivatives

With the increasing restriction and control of hazardous solvents, safer alternatives need to be identified. Here a contemporary approach to solvent selection and substitution is presented that offers a more scientific alternative to the simple “like-for-like” exchange. A new family of levoglucosenonederived compounds is proposed, modeled to determine their solvent properties, synthesized, and tested. These new molecules show promise as replacements for polar aprotic solvents that have chronic toxicity issues, such as dichloromethane, nitrobenzene, and N-methylpyrrolidinone. The success of this approach makes it possible for academia and industry to make calculated, intelligent choices for solvent substitution in the future

A step towards hydroformylation under sustainable conditions: platinum-catalysed enantioselective hydroformylation of styrene in gamma-valerolactone

Platinum-catalysed enantioselective hydroformylation of styrene was performed in γ-valerolactone (GVL) as a proposed environmentally benign reaction medium. Optically active bidentate ligands, possessing various types of chirality elements e.g. central (BDPP), axial (BINAP, SEGPHOS, DM-SEGPHOS, DTBM-SEGPHOS) and planar/central (JOSIPHOS) elements, were applied in in situ generated Pt-diphosphine-tin(II)chloride catalyst systems. In general, slightly higher activities and regioselectivities towards a branched aldehyde (2-phenylpropanal) were obtained in toluene as a reference conventional solvent. However, higher chemoselectivities towards aldehydes (up to 98%) in GVL were obtained at lower temperatures. The application of GVL proved to be also advantageous regarding enantioselectivity: although moderate enantioselectivities were obtained in both solvents, in most cases higher ee values were detected in GVL. From the mechanistic point of view, the formation of different catalytic intermediates and/or different kinetics can be envisaged from the different temperature dependences of ee in GVL and toluene. The 31P-NMR characterization of catalyst species in GVL was also provided

IMPIANTO AUTOLOGO DI CELLULE STAMINALI NOM (NASAL OLFACTORY MUCOSA) IN CANI PARAPLEGICI CRONICI\ud [AUTOLOGOUS IMPLANT OF NASAL OLFACTORY MUCOSA (NOM) STEM CELLS IN CHRONIC PARAPLEGIC DOGS]

La terapia delle lesioni spinali croniche dell’uomo rappresenta attualmente uno dei maggiori campi di interesse della ricerca scientifica. Tra le strategie sperimentali di ultima elaborazione, il trapianto di cellule staminali sta dimostrando notevoli potenzialità per la cura di molte patologie del SNC.\ud I modelli animali principalmente utilizzati per gli studi sperimentali sono i ratti, ma le dimensioni del midollo spinale in questa specie sono estremamente diverse da quelle dell’uomo, e le condizioni di laboratorio in cui i protocolli sperimentali vengono applicati sono molto differenti dalle condizioni accidentali delle lesioni umane.\ud Il trauma spinale e' un’evenienza piuttosto frequente nel cane, ma molto spesso la terapia non viene effettuata precocemente o e' inefficace, cosi' da portare ad una condizione di paraplegia cronica. In questa specie l’eziopatogenesi delle lesioni e le dimensioni del midollo sono simili a quelle dell’uomo. Per tali ragioni il cane rappresenta un buon modello per lo studio delle terapie sperimentali nelle lesioni spinali croniche. \ud Lo scopo del presente lavoro e' quello di verificare se l’impianto autologo di cellule staminali adulte di natura olfattoria sia in grado di ripristinare la deambulazione volontaria in cani paraplegici cronici.\ud Sono stati inclusi nello studio 6 soggetti sottoposti alla nostra attenzione tra gennaio 2004 e dicembre 2005 per l’insorgenza di un grave trauma spinale compreso tra le vertebre T4 e L3. Trascorsi almeno due mesi dall’insorgenza della paraplegia, in ciascun cane e' stato effettuato il prelievo bioptico della mucosa nasale. Il campione è stato quindi inviato nel laboratorio di riferimento, dove le cellule staminali sono state isolate e allestite su un apposito supporto. Nei mesi successivi tutti i 6 pazienti sono stati sottoposti all’impianto delle cellule autologhe, dopo esposizione chirurgica del segmento midollare leso e asportazione del tessuto cicatriziale. La fase post-operatoria e' stata dedicata all’esecuzione di intensi protocolli fisioterapici e di indagini cliniche e strumentali, finalizzate alla valutazione del recupero neurologico.\ud I risultati ottenuti hanno evidenziato la presenza di un parziale ripristino delle capacita' deambulatorie in 3 soggetti, mentre i tracciati elettrofisiologici relativi ai Potenziali Evocati Somato-Sensoriali (PESS) non hanno subito alcuna variazione nel periodo successivo all’impianto. In un soggetto, deceduto spontaneamente per una patologia indipendente dalla condizione neurologica, e' stato possibile sottoporre il midollo spinale a valutazioni di tipo istologico e immunoistochimico. Queste hanno evidenziato la presenza, nel tratto midollare sede dell’impianto, di gruppi di neuroni-fibre dispersi all’interno di abbondante tessuto fibroso.\ud Pur considerando l’esiguita' del numero dei soggetti inclusi nella ricerca, e in attesa di poter sottoporre ad indagini istologiche il midollo spinale di 5 di loro, si puo' concludere che l’impianto di cellule staminali di origine olfattoria nel midollo spinale di cani paraplegici cronici puo' presentare notevoli potenzialita' terapeutiche.\ud \ud The treatment of chronic spinal cord injuries in humans is, today, one of the most important fields of scientific research. Among the experimental strategies recently developed, stem cell transplants are demonstrating great potentiality for the cure of many central nervous system (CNS) pathologies.\ud The most common animal models used in experimental studies are rats but the dimensions of the spinal cord of this species are quite different from those of the human, and the laboratory conditions in which the experimental protocols are applied do not resemble the accidental conditions of human injuries.\ud Spinal cord injuries are relatively frequent in dogs but very often the therapy is not applied promptly or is not efficacious, and the result is a condition of chronic paraplegia. The etiopathogenesis of the injuries and the dimensions of the spine of the dog are similar to those of the human. For these reasons, the dog represents a good model for studying experimental treatment of chronic spinal cord injuries.\ud The aim of this study is to verify whether the autologous implant of adult stem cells obtained from nasal olfactory mucosa (NOM) is able to restore voluntary ambulation in dogs with chronic paraplegia.\ud This study concerns six subjects that we cared for between January 2004 and December 2005 after the onset of a serious spinal trauma in the area between the vertebrae T4 and L3. At least two months after the onset of paraplegia, a bioptic sample was taken from the nasal mucosa of each dog. The sample was sent to the reference laboratory where the stem cells were isolated and prepared on an appropriate scaffold. During the following months all six patients were subjected to the implant of autologous cells, after the surgical exposure of the injured segment of the spinal cord and the removal of scar tissue. The post-surgical phase was dedicated to intensive physiotherapy protocols and clinical and instrumental investigations, with the aim of evaluating the neurological recovery.\ud The results obtained demonstrated the presence of a partial restoration of the ambulatory capacity in three subjects, while the electrophysiological pathways relative to the Somatosensory Evoked Potential (SSEPs) did not undergo any variation in the period following the implant. In the case of one dog, that died spontaneously from a pathology not connected with the neurological condition, it has been possible to carry out histological and immununohistochemical evaluations of the spinal cord. These have demonstrated the presence of groups of neuron-fibres dispersed inside abundant fibrous tissue in the area of the implant.\ud While taking into consideration the small number of subjects included in the research and in anticipation of being able to subject the spinal cords of the other five dogs to histological investigations, we can nevertheless conclude that the implant of the stem cells of olfactory origin in the spinal cord of dogs with chronic paraplegia can offer outstanding therapeutic potential.\ud \ud \u