Morphology and properties evolution upon ring-opening polymerization during extrusion of cyclic butylene terephthalate and graphene-related-materials into thermally conductive nanocomposites

In this work, the study of thermal conductivity before and after in-situ ring-opening polymerization of cyclic butylene terephthalate into poly (butylene terephthalate) in presence of graphene-related materials (GRM) is addressed, to gain insight in the modification of nanocomposites morphology upon polymerization. Five types of GRM were used: one type of graphite nanoplatelets, two different grades of reduced graphene oxide (rGO) and the same rGO grades after thermal annealing for 1 hour at 1700{\deg}C under vacuum to reduce their defectiveness. Polymerization of CBT into pCBT, morphology and nanoparticle organization were investigated by means of differential scanning calorimetry, electron microscopy and rheology. Electrical and thermal properties were investigated by means of volumetric resistivity and bulk thermal conductivity measurement. In particular, the reduction of nanoflake aspect ratio during ring-opening polymerization was found to have a detrimental effect on both electrical and thermal conductivities in nanocomposites

Effect of morphology and defectiveness of graphene-related materials on the electrical and thermal conductivity of their polymer nanocomposites

In this work, electrically and thermally conductive poly (butylene terephthalate) nanocomposites were prepared by in-situ ring-opening polymerization of cyclic butylene terephthalate (CBT) in presence of a tin-based catalyst. One type of graphite nanoplatelets (GNP) and two different grades of reduced graphene oxide (rGO) were used. Furthermore, high temperature annealing treatment under vacuum at 1700{\deg}C was carried out on both RGO to reduce their defectiveness and study the correlation between the electrical/thermal properties of the nanocomposites and the nanoflakes structure/defectiveness. The morphology and quality of the nanomaterials were investigated by means of electron microscopy, x-ray photoelectron spectroscopy, thermogravimetry and Raman spectroscopy. Thermal, mechanical and electrical properties of the nanocomposites were investigated by means of rheology, dynamic mechanical thermal analysis, volumetric resistivity and thermal conductivity measurements. Physical properties of nanocomposites were correlated with the structure and defectiveness of nanoflakes, evidencing a strong dependence of properties on nanoflakes structure and defectiveness. In particular, a significant enhancement of both thermal and electrical conductivities was demonstrated upon the reduction of nanoflakes defectiveness

Role of Ligand Conformation on Nanoparticle-Protein Interactions

Engineered biomedical nanoparticles (NPs) administered via intravenous routes are prone to associate to serum proteins. The protein corona can mask the NP surface functionalization and hamper the delivery of the NP to its biological target. The design of corona-free NPs relies on our understanding of the chemical-physical features of the NP surface driving the interaction with serum proteins. Here, we address, by computational means, the interaction between human serum albumin (HSA) and a prototypical monolayer-protected Au nanoparticle. We show that both the chemical composition (charge, hydrophobicity) and the conformational preferences of the ligands decorating the NP surface affect the NP propensity to bind HSA

L'ELETTRONEUROSTIMOLAZIONE : NEUROFISIOLOGIA ED APPLICAZIONE DEI MODERNI STIMOLATORI

Spesso negli incontri di anestesisti, in occasione di seminari e congressi, si assiste a discussioni relative alla corrente minima impiegata nella realizzazione di un blocco regionale mediante elettroneurostimolazione (ENS) e alla formulazione di ipotesi sulla distanza fra la punta dell’ago-elettrodo e il nervo da bloccare. Non vengono in generale, queste discussioni, precedute da informazioni sullo stimolatore utilizzato (generatore di tensione o generatore di corrente), sulla durata dell’impulso di stimolazione, sulla posizione relativa degli elettrodi stimolante e ricevente. I volumi e le concentrazioni di anestetico usati possono risultare molto differenti. Non c’è dubbio che tutti i partecipanti alla discussione riferiscono dati reali relativi alla loro esperienza clinica quotidiana, ma questi dati sono spesso non confrontabili. Il razionale per l’esecuzione di un blocco è molto semplice. Mediante un ago-elettrodo vengono inviati, scegliendo adeguatamente il punto di accesso e in zone opportune determinate dalla buona conoscenza dell’anatomia, impulsi elettrici che attivano la contrazione di una particolare regione muscolo-tendinea. Dall’osservazione della clonia indotta si risale così all’esatta localizzazione dell’innervazione tributaria. Sulla superficie del paziente va anche ben posizionato l’elettrodo ricevente, generalmente un elettrodo da ECG autoadesivo. Il mantenimento della clonia, riducendo lo stimolo elettrico, ottenuto aumentando progressivamente l’inserimento dell’ago-elettrodo consente, con dosaggi molto limitati di anestetico, di bloccare selettivamente la componente nervosa. A parità di punto di accesso, di posizionamento dell’elettrodo di riferimento, con lo stesso stimolatore e utilizzando lo stesso tipo di aghi, due diversi operatori, sullo stesso paziente, potrebbero eseguire il blocco con volumi diversi della stessa soluzione anestetica. Infatti, a parità di condizioni operative, per le diverse esperienze, potrebbero corrispondere differenti profondità dell’ago-elettrodo e quindi risultare diverse distanze fra ago e nervo nel momento in cui viene deciso di iniettare l’anestetico. E potrebbe essere necessario, nei due casi, iniettare volumi anche molto diversi perché il bolo anestetico possa investire e interessare il nervo cercato. Sono facilmente immaginabili le ulteriori difficoltà di comunicazione quando vengono usati strumentari diversi, sia per concezione sia per caratteristiche (1). Metterò qui a fuoco alcuni punti fonte di tanta soggettività, nonostante il metodo sia chiaro a tutti e applicato da tutti con successo

Hyperthermic Perfusion 16 Years After its First Clinical Applications

It is known that above-normal temperatures (42°-42.5°C) provoke selective damage to neoplastic cells. We used heated circulating blood as a method for heat transfer on patients with limb tumors. From October 1964 to December 1979, we treated a total of 198 patients with hyperthermic perfusion for melanoma of the limbs (91), osteosarcoma (57), and soft tissue sarcoma (50). For melanoma patients, the five-year survival rate, excluding Stage IV, was 60%. For patients with soft tissue sarcoma, the five-year survival rates were 53% and 56% for hyperthermic perfusion and hyperthermic antiblastic perfusion. respectively. For 29 patients with osteosarcoma, hyperthermic perfusion was combined with systematic amputation ofthe limb for a 60% survival rate over a five-year period. Newer studies with osteosarcoma patients involve a multistep treatment that saves the tumor-bearing limb without reducing survival rates. Our 16-year clinical trial demonstrates that hyperthermia is effective in curing some tumors of the limbs, especially osteosarcoma and melanoma. We believe that perfusion remains the most reliable heat transfer method for loco-regional treatment and perhaps even for whole-body treatment for limb tumors

Ultrafast Electrochemical Self-Doping of Anodic Titanium Dioxide Nanotubes for Enhanced Electroanalytical and Photocatalytic Performance

This study explores an ultrarapid electrochemical self-doping procedure applied to anodic titanium dioxide (TiO2) nanotube arrays in an alkaline solution to boost their performance for electroanalytical and photocatalytic applications. The electrochemical self-doping process (i.e., the creation of surface Ti3+ states by applying a negative potential) is recently emerging as a simpler and cleaner way to improve the electronic properties of TiO2 compared to traditional chemical and high-temperature doping strategies. Here, self-doping was carried out through varying voltages and treatment times to identify the most performing materials without compromising their structural stability. Interestingly, cyclic voltammetry characterization revealed that undoped TiO2 shows negligible activity, whereas all self-doped materials demonstrate their suitability as electrode materials: an outstandingly short 10 s self-doping treatment leads to the highest electrochemical activity. The electrochemical detection of hydrogen peroxide was assessed as well, demonstrating a good sensitivity and a linear detection range of 3–200 µM. Additionally, the self-doped TiO2 nanotubes exhibited an enhanced photocatalytic activity compared to the untreated substrate: the degradation potential of methylene blue under UV light exposure increased by 25% in comparison to undoped materials. Overall, this study highlights the potential of ultrafast electrochemical self-doping to unleash and improve TiO2 nanotubes performances for electroanalytical and photocatalytic applications

Zooplankton as an indicator of the status of contamination of the Mediterranean Sea and temporal trends

Zooplankton has been intensively used as bioindicators of water pollution at global level, however, only few comprehensive studies have been conducted from the Mediterranean Sea and manly dated back to the 1970s. To redress the urgent need for updated data, this study provides information on the presence and levels of contaminants in zooplankton from the Tyrrhenian Sea. Although banned, both PCBs (46.9 +/- 37.2 ng g-1) and DDT (8.9 +/- 10.7 ng g-1) are still present and widespread, but their contamination appears to be a local problem and to be declining over the past 50 years. Zooplankton accumulates high levels of certain TEs, including Zn (400 +/- 388 ppm) and Pb (35.3 +/- 45.5 ppm), but shows intermediate concentrations of other TEs, including Cd (1.6 +/- 0.9 ppm) and Hg (0.1 +/- 0.1 ppm), comparing with both strongly polluted and more pristine marine habitats, which may reflect a general improvement