Synthesis and process optimization of electrospun PEEK-sulfonated nanofibers by response surface methodology

In this study electrospun nanofibers of partially sulfonated polyether ether ketone have been produced as a preliminary step for a possible development of composite proton exchange membranes for fuel cells. Response surface methodology has been employed for the modelling and optimization of the electrospinning process, using a Box-Behnken design. The investigation, based on a second order polynomial model, has been focused on the analysis of the effect of both process (voltage, tip-to-collector distance, flow rate) and material (sulfonation degree) variables on the mean fiber diameter. The final model has been verified by a series of statistical tests on the residuals and validated by a comparison procedure of samples at different sulfonation degrees, realized according to optimized conditions, for the production of homogeneous thin nanofibers

Electrically Conductive Membranes Obtained by Simultaneous Electrospinning and Electrospraying Processes

Electrically conductive polyurethane nanostructured membranes have been prepared combining the electrospinning of polymer nanofibers (NFs) with the electrospraying of pristine multiwall carbon nanotubes (MWCNTs) in simultaneous processes. In order to have a better understanding of the distribution of MWCNTs on the surface of the membranes, the optimization of the electrospraying process has been carried out and the distribution of MWCNTs has been evaluated using image texture analysis techniques. Large membranes with a volume resistivity typical of electrostatic discharge materials with a MWCNTs concentration less than 0.3% wt (0.01 mg/cm2) have been obtained and characterized with morphological (SEM and TEM) and spectroscopic (UV-Vis, Raman) techniques

Effect of dual functional ionic liquids on the thermal degradation of poly(vinyl chloride)

The short-term thermal stability of PVC on addition of functional ionic liquids (ILs) based on phosphonium and pyridinium cations, and a docusate anion, was studied using FTIR, TGA-MS and TGA-FTIR. The thermal stability of PVC plasticized with these ILs is reduced and the activation energy for thermal degradation for the first step of PVC degradation lowered, relative to neat PVC. This feature is not dependent on the thermal stability of the IL itself, as their addition to neat PVC did not result in increased thermal stability of the resin. Analysis of the gases evolved during thermal degradation showed that there is no variation in the mechanism of PVC degradation in the presence of ILs, the only difference observed is that HCl is evolved at lower temperatures for PVC-ILs samples. The ILs had no effect on the second step of the thermal degradation of PVC. The decrease in the thermal stability of PVC-ILs is associated with two different effects: firstly, the anion weakens the C-H bond while the cation forms complexes and weakens the C-Cl bond; second, the IL interaction with the polymer chains partly substitutes the interaction between the polymer chain and heat stabilizers (e.g. stearates) added to the PVC compound. In this way, the latter tends to be expelled from the bulk polymer, thus not being available for PVC stabilization at high temperature. Heat stabilizer migration is related to the solvating power of the ILs: the higher the solvating power, the higher the migration of heat stabilizer, the lower the thermal stability of the polymer

Self-assembling peptide-enriched electrospun polycaprolactone scaffolds promote the h-osteoblast adhesion and modulate differentiation-associated gene expression

Electrospun polycaprolactone (PCL) is able to support the adhesion and growth of h-osteoblasts and to delay their degradation rate to a greater extent with respect to other polyesters. The drawbacks linked to its employment in regenerative medicine arise fromits hydrophobic nature and the lack of biochemical signals linked to it. This work reports on the attempt to add five different self-assembling (SA) peptides to PCL solutions before electrospinning. The hybrid scaffolds obtained had regular fibers (SEM analysis) whose diameters were similar to those of the extracellularmatrix, more stable hydrophilic (contact angle measurement) surfaces, and anamorphous phase constrained by peptides (DSC analysis). They appeared to have a notable capacity to promote the h-osteoblast adhesion and differentiation process by increasing the gene expression of alkaline phosphatase, bone sialoprotein, and osteopontin. Adding an Arg-Gly-Asp (RGD) motif to a self-assembling sequence was found to enhance cell adhesion, while the same motif condensed with a scrambled sequence did not, indicating that there is a cooperative effect between RGD and 3D architecture created by the self-assembling peptides. The study demonstrates that self-assembling peptide scaffolds are still able to promote beneficial effects on h-osteoblasts even after they have been included in electrospun polycaprolactone. The possibility of linking biochemical messages to self-assembling peptides could lead the way to a 3D decoration of fibrous scaffolds

Facile and selective covalent grafting of an RGD-peptide to electrospun scaffolds improves HUVEC adhesion

The development of a biomimetic surface able to promote endothelialization is fundamental in the search for blood vessel substitutes that prevent the formation of thrombi or hyperplasia. This study aims at investigating the effect of functionalization of poly-ε-caprolactone or poly(L-lactic acid-co-ɛ-caprolactone) electrospun scaffolds with a photoreactive adhesive peptide. The designed peptide sequence contains four Gly-Arg-Gly-Asp-Ser-Pro motifs per chain and a p-azido-Phe residue at each terminus. Different peptide densities on the scaffold surface were obtained by simply modifying the peptide concentration used in pretreatment of the scaffold before UV irradiation. Scaffolds of poly-ε-caprolactone embeddedwith adhesive peptideswere produced to assess the importance of peptide covalent grafting. Our results show that the scaffolds functionalized with photoreactive peptides enhance adhesion at 24h with a dosedependent effect and control the proliferation of human umbilical vein endothelial cells, whereas the inclusion of adhesive peptide in the electrospun matrices by embedding does not give satisfactory results

AUTOLOGOUS STEM CELL TRANSPLANTATION IN REFRACTORY OR RELAPSED DIFFUSE LARGE B CELL LYMPHOMA – A SINGLE CENTRE EXPERIENCE

Autologna transplantacija perifernih matičnih stanica zlatni je standard u liječenju refraktornog ili relapsnoga kemosenzitivnog difuznog B-velikostaničnog limfoma u pogodnih bolesnika. Cilj je ovog rada prikazati ishode autologne transplantacije perifernih matičnih stanica u bolesnika s refraktornim ili relapsnim ne-Hodgkinovim limfomom difuznoga B-velikostaničnog tipa. Retrospektivno smo analizirali podatke 62-je bolesnika liječenih autolognom transplantacijom u našem centru u razdoblju od 2000. do 2013. godine. Većina bolesnika (71%) liječena je kemoterapijom miniBEAM, a svi su primili mijeloablativnu kemoterapiju BEAM s reinfuzijom vlastitih matičnih stanica. Ukupna stopa odgovora (kom­pletna i parcijalna remisija) nakon autologne transplantacije iznosila je 75,8%. Medijan ukupnog preživljenja iznosio je 37,2 mjeseca. Medijan preživljenja bez događaja vezanih uz bolest iznosio je 16,9 mjeseci. Čimbenici statistički značajno povezani s ukupnim preživljenjem bili su aktivnost bolesti prije visokodozne spasonosne terapije, odgovor na spasonosnu terapiju. Internacionalni prognostički indeks, stadij bolesti, odgovor na autolognu transplantaciju perifernih matičnih sta­nica te radioterapija nakon autologne transplantacije. Liječenje rituksimabom nije bilo statistički značajno povezano s ishodom. U ovoj skupini bolesnika autologna je transplantacija perifernih matičnih stanica bila učinkovita u postizanju remisije i preživljenja, što je dobar i očekivan ishod navedenog postupka. Naglašavamo da je i u skupini bolesnika s kemorezistentnom bolešću autologna transplantacija bila učinkovita u 32,5% bolesnika.Autologous stem cell transplantation represents the gold standard in chemosensitive diffuse B large cell lymphoma in relapse or in refractory setting. The aim of this study was to present the outcome of peripheral autologous stem cell transplantation in patients with refractory or relapsed diffuse large B cell lymphoma. We retrospectively analysed the data of 62 patients, who underwent this procedure for the period 2000–2013. The majority of patients (71%) were treated with miniBEAM salvage chemotherapy and all received BEAM myeloablative protocol followed by the stem cell reinfusion. The overall response rate for autologous transplantation was 75.8%. Median overall survival was 37.2 months. Median event-free survival was 16.9 months. Factors associated with overall survival were state of disease prior to salvage chemotherapy, chemosensitivity of disease, International prognostic index, disease activity at the relapse, response to autologous transplantation and post-transplantation radiotherapy. The use of rituximab was not significantly correlated to the outcome. In this patient group autologous stem cell transplantation was found to be effective in achieving remission and survival showing the adequate role of this procedure in this clinical setting. We stress out that autologous stem cell transplantation was effective in 32.5% patients with chemorefractory disease after salvage therapy

Multistructured membranes based on electro-dynamic technologies: process optimization and catalytic performances

Electodynamic technologies represent a challenging task in the nanotechnology field for producing multistructured and multifunctional membranes, based on nanofibers and nanoparticles that have been shown to be a good candidate as photocatalytic membrane on VOCs degradation. Before going toward fabrication of multistructured membranes, it is necessary to optimize the process of fiber formation. At this regard Response Surface Methodology (RSM) represents a versatile tool for exploring the space of the process or independent variables, empirical statistical modeling to develop an appropriate approximating relationship between the yield and the process variables, and optimization methods for finding the values of the process variables that produce desirable values of the response. Subsequently, it has been implemented a method for multilayer membranes fabrication in order to deposit inorganic nanoparticles and optimize their distribution over polymeric nanofibers. The processed membranes have been adequately characterized and phocatalytic performance tested.le tecnologie elettroidro dinamiche costituiscono un valido strumento nell'ambito delle nanotecnologie per la produzione di membrane multistrutturate e multifunzionali costituite da nanofibre e nanoparticelle che trovano applicazione nel settore della fotocatalisi per la rimozione di VOCs. Prima di procedere alla produzione vera e propria è necessario ottimizare il processo di elettrofilatura. a tal riguardo la metodologia di risposta delle superfici è un valido strumento per esplorare il processo, valutare e stabilire un'adeguata relazione tra la variabile risposta e le variabili di processo e rilevare la configurazione più adeguata per l'ottenimento di una fissata risposta. Successivamente, è stato implementato un metodo per la produzione di membrane multistrato in cui particelle inorganice sono depositate su nanofibre polimeriche. Tali membrane sono state adeguatamente caratterizzate ed è stata studiata la loro attività catalitica nei confronti di agenti inquinanti

ANALYSIS OF THE TOURIST SEASON OF THE SPLIT-DALMATIA COUNTY 2018.

Cilj ovoga rada je analizirati turističkusezonu u Splitsko-dalmatinskoj županiji u 2018. godini u odnosu na 2017. godinu. Tako je 2018. godine zabilježeno 3,4 milijuna dolazaka i 17,5 milijuna noćenja,što je porast za 9% u dolascima i 5% u noćenjima. Najvećiudio u smještajnim smislu, imaju privatni iznajmljivači.Što se pak tiče nautičkogturizma u Splitskodalmatinskoj županiji, daleko je ispred drugih županija na hrvatskoj obali, iako 2018. godine ima blagi pad od 1% u dolascima i 2% u noćenjima.Rezultati takođerukazuju da na području Županije u skoro svim mjesecima bilježi porast dolazaka i noćenja,te da su vodeće destinacije Split, Makarska, Baška Voda, Omiš i Tučepi.Iz ovoga razvidno zaključujemo kako je turističkasezona 2018. godine s ostvarenim prihodom od 16,1 milijuna kuna bila uspješnija od prethodne 2017. godine.The aim of this paper is to analyze the tourist season in the Split-Dalmatia County in 2018 compared to 2017. Thus, in 2018, 3.4 million arrivals and 17.5 million overnight stays were recorded, which is an increase of 9% in arrivals and 5% in overnight stays. The largest share in terms of accommodation, have private renters. As for nautical tourism in the Split-Dalmatia County, it is far ahead of other counties on the Croatian coast, although in 2018 it has a slight decline of 1% in arrivals and 2% in overnight stays. The results also indicate that in the area of the County in almost all months there is an increase in arrivals and overnight stays, and that the leading destinations are Split, Makarska, Baška Voda, Omiš and Tučepi.From this we can clearly conclude that the tourist season in 2018 with a revenue of 16.1 million kunas was more successful than the previous 2017

CONNECTION BETWEEN ACCOMMODATION DESTINATION OFFER AND SEASONALITY OF BUSINESS

Smještajna ponuda je jedan od glavnih elemenata turističkog proizvoda. Razvojem turizma kao masovne pojave dolazi do razvoja različitih oblika smještajne destinacijske ponude koja pokušava zadovoljiti turističke potrebe potražnje te stvoriti turistički doživljaj. Neadekvatno korištenje smještajne destinacijske ponude dovodi do sezonalnosti poslovanja te niske razine popunjenosti smještajnih kapaciteta u određenim mjesecima. Pojavom sezonalnosti u određenim turističkim destinacijama dovodi do neefikanosti smještajne destinacijske ponude te sezonskog generiranja prihoda. Poželjnost svake turističke destinacije je ostvariti nisku vezu smještajne destinacijske ponude sa sezonalnosti poslovanja, odnosno da je ravnomjerno raspoređena koncentracija turističke potražnje tijekom cijele godine u svim smještajnim objektima.The accommodation offer is one of the main elements of the tourist product. The development of tourism as a mass phenomenon leads to the development of various forms of accommodation destination offers that try to meet tourist needs and demand and create a tourist experience. Inadequate use of the accommodation destination offers leads to seasonality of business and a low level of occupancy of accommodation capacities in certain months. The appearance of seasonality in certain destinations leads to the inefficiency of the accommodation destination offer and seasonal income generation. The desirability of every tourist destination is to achieve a low connection between the destination's accommodation offer and the seasonality of business, that is, that there is an evenly distributed concentration of tourist demand throughout the year in all accommodation facilities

CONNECTION BETWEEN ACCOMMODATION DESTINATION OFFER AND SEASONALITY OF BUSINESS

Smještajna ponuda je jedan od glavnih elemenata turističkog proizvoda. Razvojem turizma kao masovne pojave dolazi do razvoja različitih oblika smještajne destinacijske ponude koja pokušava zadovoljiti turističke potrebe potražnje te stvoriti turistički doživljaj. Neadekvatno korištenje smještajne destinacijske ponude dovodi do sezonalnosti poslovanja te niske razine popunjenosti smještajnih kapaciteta u određenim mjesecima. Pojavom sezonalnosti u određenim turističkim destinacijama dovodi do neefikanosti smještajne destinacijske ponude te sezonskog generiranja prihoda. Poželjnost svake turističke destinacije je ostvariti nisku vezu smještajne destinacijske ponude sa sezonalnosti poslovanja, odnosno da je ravnomjerno raspoređena koncentracija turističke potražnje tijekom cijele godine u svim smještajnim objektima.The accommodation offer is one of the main elements of the tourist product. The development of tourism as a mass phenomenon leads to the development of various forms of accommodation destination offers that try to meet tourist needs and demand and create a tourist experience. Inadequate use of the accommodation destination offers leads to seasonality of business and a low level of occupancy of accommodation capacities in certain months. The appearance of seasonality in certain destinations leads to the inefficiency of the accommodation destination offer and seasonal income generation. The desirability of every tourist destination is to achieve a low connection between the destination's accommodation offer and the seasonality of business, that is, that there is an evenly distributed concentration of tourist demand throughout the year in all accommodation facilities