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

Presence of multiple bacterial markers in clinical samples might be useful for presumptive diagnosis of infection in cirrhotic patients with culture-negative reports

Bacterial infections in cirrhotic patients with ascites are associated with a severe prognosis and an increased risk of death. The microbiological standard tests for the diagnosis of suspected infection, based on culture test of blood and ascitic fluid, are, in many cases (30-40 %), negative, even when patients show symptoms of infection. A multiple culture-independent protocol was applied and evaluated as a diagnostic and prognostic tool for the detection of bacterial infection in cirrhotic patients. Sixty-four culture-negative samples obtained from 34 cirrhotic patients, with PMN < 250 cells/μl of ascitic fluid, were screened for the presence of bacterial DNA, endotoxin, peptidoglycan/β-glucan and microscopically visible bacterial cells. Correlations between the presence of multiple markers and various clinical and laboratory parameters were evaluated. Bacterial DNA was detected in 23 samples collected from 16 patients; a large part of these samples also showed the presence of other bacterial markers, which was associated with a worsening of liver functionality, a higher incidence of infections during the follow-up and a higher mortality rate in our cohort of cirrhotic patients. We believe that the detection of additional bacterial markers in bacterial DNA-positive clinical samples makes the bacterial presence and its clinical significance more realistic and might be useful as early markers of an ongoing bacterial infection and in establishing a clinical prognosis

Sviluppo di blend polimerici per il miglioramento delle proprietà barriera di polimeri per il packaging alimentare

Il lavoro di tesi ha previsto lo svolgimento di un'attività di ricerca atta all'individuazione di opportune soluzioni in grado di realizzare il miglioramento delle prestazioni barriera di materiali impiegati nel settore del packaging alimentare finalizzato alla riduzione dello spessore dei contenitori per bevande per ottenere una riduzione nei costi e nell'impatto ambientale associato al trasporto sul mercato finale del prodotto. In particolare lo studio si concentrato sulla realizzazione di blend polimerici a matrice PET e PLA con l'aggiunta di piccole percentuali di polimeri barriera. Tali blend sono stati caratterizzati e sono state condotte misure di permeabilit che hanno mostrato un certo miglioramento nelle prestazioni dei blend rispetto al comportamento delle matriciopenEmbargo per motivi di segretezza e/o di proprietà dei risultati e informazioni di enti esterni o aziende private che hanno partecipato alla realizzazione del lavoro di ricerca relativo alla tes

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

Kiri tundmatule

Boaretti, Francesco, 1748-1799, itaalia kirjani

COMPOSTING OF STARCH-BASED BIOPLASTIC BAGS: SMALL SCALE TEST OF DEGRADATION AND SIZE REDUCTION TREND

In Italy, the majority of bioplastic bags used in food waste collection is made of starch-based biopolymer. The compostability of this material in a full-scale plant remains to be demonstrated, largely due to the fact that bioplastic bags are screened and removed together with conventional plastic bags during pre-treatment steps. The present research was performed on a small scale to study the degradation of starch-based bioplastics during composting. Evolution of the physical and chemical parameters of the material was evaluated by means of Fourier Transform Infrared (FTIR), experimental mass loss and granulometric trend. The results obtained suggested that fragmentation (physical size reduction of the material) occurred mainly during the thermophilic phase, while biodegradation (breakdown by microorganisms of an organic chemical into simpler, innocuous compounds) occurred during the curing phase. Based on the monitored parameters (TS, VS, pH, C/N and RI4), the composting process of the waste matrix ended after 55 days, but the degradation of bioplastics failed to achieve the regulatory standards for assessment of compostability ( 64 10% sized > 2 mm). Experimental data revealed a linear trend for the fragmentation process and a duration of 100 days would be required to meet regulatory requirement

Inhibition of Pseudomonas aeruginosa secreted virulence factors reduces lung inflammation in CF mice

Cystic fibrosis (CF) lung infection is a complex condition where opportunistic pathogens and defective immune system cooperate in developing a constant cycle of infection and inflammation. The major pathogen, Pseudomonas aeruginosa, secretes a multitude of virulence factors involved in host immune response and lung tissue damage. In this study, we examined the possible anti-inflammatory effects of molecules inhibiting P. aeruginosa virulence factors

Toothbrushes may convey bacteria to the cystic fibrosis lower airways

Recent findings indicate that the oral cavity acts as a bacterial reservoir and might contribute to the transmission of bacteria to the lower airways. Control of a potentially pathogenic microbiota might contribute to prevent the establishment of chronic infection in cystic fibrosis. We evaluated the presence of CF microorganisms in saliva and toothbrushes of CF patients and verify their possible transmission to lower airways. Methods: We assessed the presence of P. aeruginosa, S. aureus, S. maltophilia, A. xylosoxidans, S. marcescens, and yeasts in saliva, toothbrushes and sputum of 38 CF patients and assessed the clonal identity of the strains occurring contemporary in multiple sites by PFGE. Results: At least one of the investigated species was isolated from 60 saliva samples and 23 toothbrushes. S. aureus was the most abundant species, followed by Candida spp. 31 patients contemporary had the same species in sputum and saliva/toothbrush: in most cases, clonal identity of the strains among the different sites was confirmed. Conclusion: Toothbrushes may be sources of oral contamination and might act as reservoirs favoring transmission of potentially pathogenic microorganisms from the environment to the oral cavity and eventually to the LAW. Oral hygiene and toothbrush care are important strategies to prevent CF lung infections

A GEOMETRIA NO ENSINO FUNDAMENTAL 2: dos Parâmetros Curriculares Nacionais à Base Nacional Comum Curricular

Esse artigo é resultado das discussões tecidas ao longo do desenvolvimento da disciplina Ensino e Aprendizagem de Geometria na Educação Básica, ministrada no (contexto identificador - retirado). Com o objetivo de analisar como é proposto o ensino de Geometria nos anos finais do Ensino Fundamental, de acordo com os PCN e a BNCC, e identificar aproximações e distanciamentos entre essas propostas, dialogamos com o referencial teórico metodológico da Hermenêutica de Profundidade, proposto por John B. Thompson, para compreender tanto aspectos internos destes documentos, tais como sua organização, objetivos e propostas relacionadas ao ensino de Geometria por etapas, como também os aspectos relacionados ao contexto social, político e econômico no qual esses documentos foram produzidos e disseminados. Dentre várias discussões acerca desses movimentos, destacamos que alguns conteúdos passaram a figurar em ciclos diferentes, tendo sido antecipados; a BNCC ampliou a abordagem de alguns conceitos e procedimentos ao propor a exploração da descrição de algoritmos para construções geométricas e para a resolução de problemas; ademais, alguns conteúdos que constavam nos PCN dos anos finais do Ensino Fundamental não estão contemplados na BNCC, entretanto, nossos dados são insuficientes para afirmar que estes tenham sido suprimidos, sendo necessário cotejá-los com os PCN dos anos iniciais do Ensino Fundamental e do Ensino Médio, a fim de verificar a possibilidade de estes terem sido antecipados ou postergados