Polymeric aerogels

2012 - 2013Aerogels are a unique class of materials characterized by a highly porous network, being attractive for many applications such as thermal and acoustic insulation, capacitors or catalysis. In more recent years, polymeric aerogels based on thermoplastic uncrosslinked polymers, where the knots of the three-dimensional networks are physical, not formed by covalent chemical bonds but by small crystallites, have been obtained. These physically cross-linked aerogels are generally prepared by supercritical CO2 extraction of thermoreversible organogels. Besides aerogels, another class of porous materials, which has received attention in the last decade by the scientific community, is constituted by semicrystalline thermoplastic polymers whose crystalline phase is nanoporous, i.e. presents a density lower than the corresponding amorphous phase. In this thesis monolithic aerogels, where the crystallites that constitute the physical knots exhibit a nanoporous-crystalline form have been prepared for polymer that exhibit a nanoporous crystalline phase e.g. syndiotactic polystyrene (s-PS) and poly(2,6-dimethyl-1,4-phenylene)oxide (PPO).[2c] Physically cross-linked aerogels have also been prepared for poly(2,6-diphenyl-1,4-phenylene oxide) (PPPO), that does not exhibit a nanoporous crystalline phase, but a highly absorbent amorphous phase.[2d] Moreover the preparation of aerogels of polyethylene, is described. The fast kinetics and high sorption capacity of VOCs by aerogels, as well as their good handling characteristics, make these new materials particularly suitable as a sorption medium to remove selectively traces of pollutants from water and air. Furthermore nanocomposites aerogels, with large amounts of both intercalated and exfoliated organically modified montmorillonite (OMMT) and including the nanoporous-crystalline δ form of s-PS, were prepared. Also for high OMMT content, the aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Analogous aerogels were prepared with graphene oxide (GO) leading to complete GO exfoliation as well as its substantial reduction. The most important result is that the aerogel preparation allows the inclusion of also large amount of nanofillers, without aggregation, at least up to a content of 20 wt%. This allows to improve mechanical and electrical properties of the nanoporous-crystalline aerogels of s-PS. Composite aerogels exhibiting large nanofiller content, can be also used as masterbatches for polymer composites. [edited by author]XII n.s

Gap Analysis Report

Julkaistu versi

Narrazioni affettive nella gestione del diabete di tipo 1. Studio pilota di una triade familiare

Il diabete mellito tipo 1 è una malattia cronica dovuta ad un disordine metabolico ad eziologia multipla. Definita da Bury (2005) come una “discordanza biografica”, il suo trattamento si basa sul coinvolgimento attivo delle famiglie e rende necessario una riorganizzare della vita quotidiana del paziente e della famiglia. Lo studio ha lo scopo di analizzare le interazioni di una triade familiare in termini di modalità enabling (facilitante) e constraining (ostacolante) e l’influenza sulla salute del ragazzo di queste modalità comunicative. Gli strumenti self report, come la Scala degli ambiti di discussione familiari (Gambini, 2008) per il tema scelto e il Sample Diabetes Questionnaire (SDQ) dello Stanford Patient Education Research Center (2007), per la salute del paziente, hanno affiancato lo strumento Constraining and Enabling Coding System (CECS; Hauser, et al.1991 adattato da Chiarolanza, et al. 2016) per le analisi dell’interazione videoregistrata di una triade familiare. Dall’analisi delle interazioni emerge che le forme comunicative nella triade si orientano verso modalità comunicative della dimensione cognitiva vincolante. Questo sembra interferire sul monitoraggio della glicemia e sul rapporto del figlio col medico. La modalità con cui i membri di una triade riescono a coordinarsi o non, dunque, durante un’interazione sembra avere effetti sulla salute dell’adolescente sia declinata come qualità delle relazioni familiari che di benessereThe type 1 diabetes mellitus is a chronic disease caused by a metabolic disorder with multiple etiologies. Defined by Bury (2005) as a "biographical disagreement ", its treatment is based on the active involvement of families and makes it necessary to reorganize both patient daily life and his/her family one. This paper aims to analyze the interactions of a family triad in terms of enabling and constraining style and how this type of communication has an impact on the child health. We utilized for this study self-report questionnaires and Constraining and Enabling Coding System (CECS; Hauser, et al.,1991 adapted by Chiarolanza, et al., 2016) for analysis of a family triad interaction. Results showed that interactive communication in the triad are oriented towards constraining cognitive dimension. This could interfere with blood glucose monitoring and the patient relationship with integrated team care. Members of a triad can coordinate or not during a family interaction and this could have effects on adolescent health in terms of quality of family relationships and well bein

Recent Advances in N-Heterocyclic Carbene Coinage Metal Complexes in A3-Coupling and Carboxylation Reaction

Owing of their accessibility and wide range of reactivities, alkynes make for fascinating building blocks. Either a selective alkyne carbon-carbon triple bond reaction or activation of the terminal alkyne C-H bond may be employed to functionalize them. Monocationic coinage metal complexes with a d10 electronic configuration are effective catalysts for alkyne activation. Silver(I) and gold(I) N-heterocyclic (NHC) systems are emerging as promising catalysts in multicomponent alkyne activation reactions; this review paper focuses on A3 (aldehyde-amine-alkyne)-coupling reaction and carbon dioxide fixation, furnishing a systematic overview of the scientific advances achieved during the last two decades. This study will carefully compare the corresponding silver and gold complexes employed in the two processes. The differences in reaction routes brought about by the catalyst ligand structure will be investigated with an emphasis on evaluating the benefits provided by the easily tuneable NHC backbone, in terms of chemo- and stereo-selectivit

Satellite Lidar Measurements as a Critical New Global Ocean Climate Record

The year 2023 marked the tenth anniversary of the first published description of global ocean plankton stocks based on measurements from a satellite lidar. Diverse studies have since been conducted to further refine and validate the lidar retrievals and use them to discover new characteristics of plankton seasonal dynamics and marine animal migrations, as well as evaluate geophysical products from traditional passive ocean color sensors. Surprisingly, all of these developments have been achieved with lidar instruments not designed for ocean applications. Over this same decade, we have witnessed unprecedented changes in ocean ecosystems at unexpected rates and driven by a multitude of environmental stressors, with a dominant factor being climate warming. Understanding, predicting, and responding to these ecosystem changes requires a global ocean observing network linking satellite, in situ, and modeling approaches. Inspired by recent successes, we promote here the creation of a lidar global ocean climate record as a key element in this envisioned advanced observing system. Contributing to this record, we announce the development of a new satellite lidar mission with ocean-observing capabilities and then discuss additional technological advances that can be envisioned for subsequent missions. Finally, we discuss how a potential near-term gap in global ocean lidar data might, at least partially, be filled using on-orbit or soon-to-be-launched lidars designed for other disciplinary purposes, and we identify upcoming needs for in situ support systems and science community development

A pilot study of brisk walking in sedentary combination antiretroviral treatment (cART)- treated patients: benefit on soluble and cell inflammatory markers

Background: Chronic HIV infection is associated with low-level inflammation and increased risk of chronic diseases and mortality. The objective was to assess the effects of moderate intensity exercise on metabolic and inflammatory markers in HIV-infected treated persons. Methods: This was a pilot study enrolling cART-treated, sedentary persons with metabolic complications in a 12-week protocol, consisting of three sessions per week of 60 min brisk walking with (strength-walk group) or without (walk group) 30 min circuit-training. Assessments at baseline and week 12 (W12) included body morphometrics and total body dual-energy X-ray absorptiometry; lipid and glucose blood profile; plasma level of high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), D-dimer, interleukin-18 (IL-18), soluble CD14, and CD38 and HLA-DR expression on CD4+ and CD8+ T-cells. Results: Forty-nine patients were included and 35 (71%) completed the program: 21 in the walk and 14 in the strength-walk group. At W12, significant improvements were observed of body mass index, waist and hip circumference, and total cholesterol both overall and in the walk group, and of LDL cholesterol in both training groups. In the whole group, significant reductions were observed in hsCRP, IL-6, D-dimer, IL-18, and of CD8 +/CD38+/HLA-DR+ cell frequencies. HsCRP and CD8+/CD38+/HLA-DR+ frequency decreased significantly in both training groups when examined separately whereas IL-6 and D-dimer in the walk group only. Conclusions: Brisk walking, with or without strength exercise, could improve lipid profile and inflammatory markers in chronic HIV infection

Genome analysis and gene expression profiling of neuroblastoma and ganglioneuroblastoma reveal differences between neuroblastic and Schwannian stromal cells

Neuroblastic tumours are a group of paediatric cancers with marked morphological heterogeneity. Neuroblastoma (Schwannian stroma-poor) (NB-SP) is composed of undifferentiated neuroblasts. Ganglioneuroblastoma intermixed (Schwannian stroma-rich) (GNBi-SR) is predominantly composed of Schwannian stromal (SS) and neuroblastic (Nb) cells. There are contrasting reports suggesting that SS cells are non-neoplastic. In the present study, laser capture microdissection (LCM) was employed to isolate SS and Nb cells. Chromosome 1p36 deletion and MYCN gene amplification were found to be associated in two out of seven NB-SPs, whereas no abnormalities were observed in five GNBi-SRs. In some cases, loss of heterozygosity (LOH) at 1p36 loci was detected in Nb cells but not in the bulk tumour by LCM; furthermore, LOH was also identified in both SS and tumour tissue of a GNBi-SR. DNA gain and loss studied by comparative genomic hybridization were observed at several chromosome regions in NB-SP but in few regions of GNBi-SR. Finally, gene expression profiles studied using an oligo-microarray technique displayed two distinct signatures: in the first, 32 genes were expressed in NB-SP and in the second, 14 genes were expressed in GNBi-SR. The results show that NB-SP is composed of different morphologically indistinguishable malignant cell clones harbouring cryptic mutations that are detectable only after LCM. The degree of DNA imbalance is higher in NB-SP than in GNBi-SR. However, when the analysis of chromosome 1p36 is performed at the level of microdissection, LOH is also observed in SS cells. These data provide supportive evidence that SS cells have a less aggressive phenotype and play a role in tumour maturation. Copyright © 2005 Pathological Society of Great Britain and Ireland

Storiografia filosofica e storiografia religiosa. Due punti di vista a confronto. Scritti in onore di Luciano Malusa

Il volume raccoglie una trentina di contributi sul tema della storiografia filosofica nel suo rapporto con la storiografia religiosa