73 research outputs found
Selective localization of nanoparticles in microstructured systems
The research activities carried out during the doctoral program focused on selective localization of nanoparticles in microstructured polymer systems. Three distinct processes, very different from each other, were employed to achieve similar results.
The first area of research has involved the selective localization of the carbon nanotubes within a biphasic and bicontinuous blend of polystyrene and polylactic acid, obtained by melt mixing the two thermoplastic polymers. Nanoparticles were selectively dispersed in the polystyrene phase achieving a lower percolation threshold than the initial one.
In the second line of research, carried out in collaboration with the Soft Matter Physics group of the Adolphe Merkle Institute (Fribourg, Switzerland), hybrid organometallic perovkite nanocrystals were produced by precipitation in liquid phase. These nanocrystals were then incorporated into a thin film of polyethylene glycol diacrylate deposited by spin-coating on a glass substrate. The polymer crosslinking, triggered by exposure to an oxygen plasma, induced the formation of corrugations on the film surface (wrinkles) allowing the microstructuring of the perovskite.
In the third line of research, carried out in collaboration with the National Institute of Optics (INO-CNR), selective localization of quantum dots in polydimethylsiloxane microlenses on a pyroelectric lithium niobate substrate were achieved through electrohydrodynamic and dielectrophoretic mechanisms. The lithium niobate substrate was periodically poled in an hexagonal pattern using finite element simulations to predict the final position of particles
On the Spraying Modality of Liquids by Pyroelectrohydrodynamics
We present for the first time an investigation on the spraying modality for the pyroelectrohydrodynamic (pyro-EHD) system. We show that the pyro-EHD spray (p-Spray) works well in the range from far field (d > 10 mm) to near field (d < 2 mm) without the need of external voltage and without the needs to change the experimental apparatus in that wide range of distances. Because the proposed method works without a counter electrode, no limitations are connected with the geometric shape of the substrate on which the spray coating is deposited. We report on several examples of the formation of disperse sprayed droplets, whose size can be varied between hundreds of micrometers and hundreds of nanometers, as well as on the production of sprayed pattern footpaths. The results reported here demonstrate the direct writing of spray patterns of nano/microdroplets with different materials in a very wide range, that is, from low- to high-viscous liquid solutions. Finally, as an example of application, we show the use of..
Discontinuation of first-line bevacizumab in metastatic colorectal cancer: the BEAWARE Italian Observational Study
BEAWARE investigated the pattern of first-line bevacizumab early interruption in the Italian real-world setting of metastatic colorectal cancer
Origin of Sn(II) oxidation in tin halide perovskites
Tin-halide perovskites have great potential as photovoltaic materials, but their performance is hampered by undesirable oxidation of Sn(ii) to Sn(iv). NMR proves DMSO to be a main cause of oxidation
Fluoride Chemistry in Tin Halide Perovskites
Tin is the frontrunner for substituting toxic lead in perovskite solar cells. However, tin suffers the detrimental oxidation of SnII to SnIV. Most of reported strategies employ SnF2 in the perovskite precursor solution to prevent SnIV formation. Nevertheless, the working mechanism of this additive remains debated. To further elucidate it, we investigate the fluoride chemistry in tin halide perovskites by complementary analytical tools. NMR analysis of the precursor solution discloses a strong preferential affinity of fluoride anions for SnIV over SnII, selectively complexing it as SnF4. Hard X-ray photoelectron spectroscopy on films shows the lower tendency of SnF4 than SnI4 to get included in the perovskite structure, hence preventing the inclusion of SnIV in the film. Finally, small-angle X-ray scattering reveals the strong influence of fluoride on the colloidal chemistry of precursor dispersions, directly affecting perovskite crystallization
Prognostic and predictive role of EGFR pathway alterations in biliary cancer patients treated with chemotherapy and anti-EGFR
The association of anti-EGFR to gemcitabine and oxaliplatin (GEMOX) chemotherapy did not improve survival in biliary tract carcinoma (BTC) patients. Multiple mechanisms might be involved in the resistance to anti-EGFR. Here, we explored the mutation profile of EGFR extracellular domain (ECD), of tyrosine kinase domain (TKD), and its amplification status. EGFR mutational status of exons 12, 18-21 was analyzed in 57 tumors by Sanger sequencing. EGFR amplification was evaluated in 37 tumors by Fluorescent In Situ Hybridization (FISH). Kaplan-Meier curves were calculated using the log-rank test. Six patients had mutations in exon 12 of EGFR ECD and 7 in EGFR TKD. Neither EGFR ECD nor TKD mutations affected progression free survival (PFS) or overall survival (OS) in the entire population. In the panitumumab plus GEMOX (P-GEMOX) arm, ECD mutated patients had a worse OS, while EGFR TKD mutated patients had a trend towards shorter PFS and OS. Overall, the presence of mutations in EGFR or in its transducers did not affect PFS or OS, while the extrahepatic cholangiocarcinoma (ECC) mutated patients had a worse prognosis compared to WT. Nineteen out of 37 tumors were EGFR amplified, but the amplification did not correlate with survival. ECC EGFR amplified patients had improved OS, whereas the amplification significantly correlated with poor PFS (p = 0.03) in gallbladder carcinoma patients. The high molecular heterogeneity is a predominant feature of BTC: the alterations found in this work seem to have a prognostic impact rather than a predictive role towards anti-EGFR therapy
Photovoltaic potential of tin perovskites revealed through layer-by-layer investigation of optoelectronic and charge transport properties
Tin perovskites are the most promising environmentally friendly alternative
to lead perovskites. Among tin perovskites, FASnI3 (CH4N2SnI3) shows optimum
band gap, and easy processability. However, the performance of FASnI3 based
solar cells is incomparable to lead perovskites for several reasons, including
energy band mismatch between the perovskite absorber film and the charge
transporting layers (CTLs) for both types of carriers, i.e., for electrons
(ETLs) and holes (HTLs). However, the band diagrams in the literature are
inconsistent, and the charge extraction dynamics are poorly understood. In this
paper, we study the energy band positions of FASnI3 based perovskites using
Kelvin probe (KP) and photoelectron yield spectroscopy (PYS) to provide a
precise band diagram of the most used device stack. In addition, we analyze the
defects within the current energetic landscape of tin perovskites. We uncover
the role of bathocuproine (BCP) in enhancing the electron extraction at the
fullerene C60/BCP interface. Furthermore, we used transient surface
photovoltage (tr-SPV) for the first time for tin perovskites to understand the
charge extraction dynamics of the most reported HTLs such as NiOx and PEDOT,
and ETLs such as C60, ICBA, and PCBM. Finally, we used Hall effect, KP, and
time-resolved photoluminescence (TRPL) to estimate an accurate value of the
p-doping concentration in FASnI3 and showed a consistent result of 1.5 * 1017
cm-3. Our findings prove that the energetic system of tin halide perovskites is
deformed and should be redesigned independently from lead perovskites to unlock
the full potential of tin perovskites.Comment: 22 pages, 5 figure
Fluoridchemie in ZinnâHalogenidâPerowskiten
Zinn ist der Top-Favorit fĂŒr den Ersatz von giftigem Blei in Perowskit-Solarzellen. Allerdings kommt es dabei verstĂ€rkt zu der unerwĂŒnschten Oxidation von SnII zu SnIV. Die herkömmlichen Verfahren verwenden SnF2 in der Perowskit-VorlĂ€uferlösung, um die Bildung von SnIV zu verhindern. Dennoch bleibt der Wirkmechanismus des Additivs unklar. Um diesen eingehender zu erlĂ€utern, untersuchen wir die Fluoridchemie in Zinn-Halogenid-Perowskiten mit einander ergĂ€nzenden Analyseverfahren. NMR-Spektroskopie der VorlĂ€uferlösung offenbart eine stark bevorzugte AffinitĂ€t der Fluoridanionen fĂŒr SnIV gegenĂŒber SnII, wodurch dieses selektiv als SnF4 komplexiert wird. Harte Röntgenphotoelektronenspektroskopie an DĂŒnnschichten zeigt die geringere Bereitschaft von SnF4 gegenĂŒber SnI4, in die Perowskit-Struktur eingebaut zu werden und verhindert somit den Einschluss von SnIV in der DĂŒnnschicht. AbschlieĂend offenbart Röntgen-Kleinwinkelstreuung den starken Einfluss vom Fluorid auf die kolloidale Chemie der VorlĂ€uferlösungen, der sich direkt auf die darauffolgende Kristallisation auswirkt.European Research Council (ERC)Peer Reviewe
Cetuximab continuation after first progression in metastatic colorectal cancer (CAPRI-GOIM): A randomized phase II trial of FOLFOX plus cetuximab versus FOLFOX
Background: Cetuximab plus chemotherapy is a first-line treatment option in metastatic KRAS and NRAS wild-type colorectal cancer (CRC) patients. No data are currently available on continuing anti-epidermal growth factor receptor (EGFR) therapy beyond progression. Patients and methods: We did this open-label, 1:1 randomized phase II trial at 25 hospitals in Italy to evaluate the efficacy of cetuximab plus 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX) as second-line treatment of KRAS exon 2 wild-type metastatic CRC patients treated in first line with 5-fluorouracil, folinic acid and irinotecan (FOLFIRI) plus cetuximab. Patients received FOLFOX plus cetuximab (arm A) or FOLFOX (arm B). Primary end point was progressionfree survival (PFS). Tumour tissues were assessed by next-generation sequencing (NGS). This report is the final analysis. Results: Between 1 February 2010 and 28 September 2014, 153 patients were randomized (74 in arm A and 79 in arm B). Median PFS was 6.4 [95% confidence interval (CI) 4.7-8.0] versus 4.5 months (95% CI 3.3-5.7); [hazard ratio (HR), 0.81; 95% CI 0.58-1.12; P = 0.19], respectively. NGS was performed in 117/153 (76.5%) cases; 66/117 patients (34 in arm A and 32 in arm B) had KRAS, NRAS, BRAF and PIK3CA wild-type tumours. For these patients, PFS was longer in the FOLFOX plus cetuximab arm [median 6.9 (95% CI 5.5-8.2) versus 5.3 months (95% CI 3.7-6.9); HR, 0.56 (95% CI 0.33-0.94); P = 0.025]. There was a trend in better overall survival: median 23.7 [(95% CI 19.4-28.0) versus 19.8 months (95% CI 14.9-24.7); HR, 0.57 (95% CI 0.32-1.02); P = 0.056]. Conclusions: Continuing cetuximab treatment in combination with chemotherapy is of potential therapeutic efficacy in molecularly selected patients and should be validated in randomized phase III trials
An open-access database and analysis tool for perovskite solar cells based on the FAIR data principles
Large datasets are now ubiquitous as technology enables higher-throughput experiments, but rarely can a research field truly benefit from the research data generated due to inconsistent formatting, undocumented storage or improper dissemination. Here we extract all the meaningful device data from peer-reviewed papers on metal-halide perovskite solar cells published so far and make them available in a database. We collect data from over 42,400 photovoltaic devices with up to 100 parameters per device. We then develop open-source and accessible procedures to analyse the data, providing examples of insights that can be gleaned from the analysis of a large dataset. The database, graphics and analysis tools are made available to the community and will continue to evolve as an open-source initiative. This approach of extensively capturing the progress of an entire field, including sorting, interactive exploration and graphical representation of the data, will be applicable to many fields in materials science, engineering and biosciences
- âŠ