51 research outputs found

    Conditions for efficient charge generation preceded by energy transfer process in non-fullerene organic solar cells

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    The minimum driving force strategy is applied to promote the exciton dissociation in organic solar cells (OSCs) without significant loss of open-circuit voltage. However, this strategy tends to promote F\"orster resonance energy transfer (FRET) from the donor to the acceptor (D-A), a consequence generally ignored until recently. In spite of the advances reported on this topic, the correlation between charge-transfer (CT) state binding energy and driving force remains unclear, especially in the presence of D-A FRET. To address this question, we employ a kinetic approach to model the charge separation in ten different D/A blends using non-fullerene acceptors. The model considers the influence of FRET on photoluminescence (PL) quenching efficiency. It successfully predicts the measured PL quenching efficiency for D or A photoexcitation in those blends, including the ones for which the D-A FRET process is relevant. Furthermore, the application of the model allows to quantifying the fractions of quenching loss associated with charge transfer and energy transfer. Fundamental relationships that controls the exciton dissociation was derived evidencing the key roles played by the Marcus inverted regime, exciton lifetime and mainly by the correlation between the driving force and binding energy of CT state. Based on those findings, we propose some strategies to maximize the quenching efficiency and minimize energy loss of OSCs in the presence of D-A FRET.Comment: 44 pages, 10 figures, 3 table

    PO-338 Recurrent glioblastoma: a complex scenario dominated by loss of MMR proteins

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    Introduction Glioblastoma (GBM) is the most common primary brain tumour in adults and the Stupp protocol represents the standard of care. However, the tumour invariably relapses suggesting marked intra-tumour genetic heterogeneity enabling rapid adaptation to therapy. In-depth characterisation of recurrent GBM (rGBM) might contribute to better understand mechanisms behind tumour progression and enable rGBM treatment with targeted drugs. Material and methods Matched GBM samples have been collected at diagnosis and recurrence from adult patients (n=57) treated with the Stupp protocol. Expression of mismatch repair (MMR) proteins (MLH1, PMS2, MSH2, MSH6) was evaluated by IHC, followed by exome sequencing of 3 pairs showing loss of MSH6 reactivity as well as of 3 MSH6 positive pairs. In addition, established genetic and epigenetic markers of GBM were investigated along with their correlation with loss of MMR proteins and patients' survival. Results and discussions According to IHC results, 13 out of 52 rGBM samples (25%) lacked expression of MMR proteins. In particular, 11 among the 13 samples (85%) showed partial or total reduction of MSH6 expression. Conversely, almost all GBM samples at diagnosis (96.4%) stained positive for the 4 MMR markers. Consistent with IHC data, exome sequencing disclosed lack of variants in MMR genes in primary samples whereas rGBM samples lacking MSH6 expression were mutated in the abovementioned genes and shared a c.3438+1G>A* splicing variant in MSH6 with a potential loss of function effect. Moreover, MSH6 negative relapsed specimens were characterised by 30 to 100-fold more variants compared to the matched primary ones and lacked microsatellite instability. Notably, MMR deficiency was associated with significant telomere shortening. Conversely, the tumour pairs expressing MMR proteins showed an almost comparable number of mutations in primary versus relapsed samples and absence of variants in MMR genes both in the initial tumours and in their recurrent counterpart. Conclusion Our study shows that IHC staining is a valuable tool to identify a subset of rGBM patients with alterations in MMR genes linked to high mutational burden and, hence, potentially eligible for drugs targeting immune checkpoint inhibitors

    Dianthracenylazatrioxa[8]circulene: synthesis, characterization and application in OLEDs

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    A soluble, green-blue fluorescent, pi-extended azatrioxa[8]circulene was synthesized by oxidative condensation of a 3,6-dihydroxycarbazole and 1,4-anthraquinone by using benzofuran scaffolding. This is the first circulene to incorporate anthracene within its carbon framework. Solvent-dependent fluorescence and bright green electroluminescence accompanied by excimer emission are the key optical properties of this material. The presence of sliding pi-stacked columns in the single crystal of dianthracenylazatrioxa[8]circulene is found to cause a very high electron-hopping rate, thus making this material a promising n-type organic semiconductor with an electron mobility predicted to be around 2.26 cm(2) V-1 s(-1). The best organic light-emitting diode (OLED) device based on the dianthracenylazatrioxa[8]circulene fluorescent emitter has a brightness of around 16 000 Cd m(-2) and an external quantum efficiency of 3.3 %. Quantum dot-based OLEDs were fabricated by using dianthracenylazatrioxa[8]circulene as a host matrix material.Peer reviewe

    Socratic dialogue: a comparison between ancient and contemporary method (substantive revision 2015)

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    These last years have witnessed the emergence and blossoming of practices inspired by philosophy on the didactic and pedagogical scene. In this context, Socrates’ philosophy represents one main point of reference. Socratic dialogue is now a model for a maieutic conception of teaching as well as for the constitution of dialogical communities and for an interrogative inquiry into reality. However, at times this recovery of the Socratic model is not exempt from misunderstandings and anachronisms. The aim of this entry is to underline the main differences between the ancient and contemporary method

    Predicting invasive signal crayfish (Pacifastacus leniusculus) spread using a traditional survey and river network simulation

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    Rivers are among the most vulnerable ecosystems to biological invasions. After introduction, predicting the timing and magnitude of population growth and range expansion is critical to decision making on where management tactics will be most efficient. Yet, management is often hindered by the lack of knowledge on species-specific attributes and the spatially complex structure of river networks that influences connectivity between sites. We analysed the population structure and predicted the range expansion of signal crayfish (Pacifastacus leniusculus), an invasive species in North-western Italy which was first recorded in the Valla Stream in 2009 and then spread to adjacent rivers including Erro Stream in 2020. A total of 1,284 individual P. leniusculus crayfish were collected in the Valla Stream. No significant difference was found in density or body condition along a downstream gradient for different sex and maturity classes. These empirical data were combined with the available scientific literature to obtain key life-history information for P. leniusculus, including carrying capacity, downstream versus upstream dispersion and proliferation rate. We used the OCNet R package to simulate the Erro Stream network and applied a meta-population model to predict the range expansion of this species over time. Results indicate P. leniusculus may completely invade the Erro Stream network in 30–40 years, depending on the proliferation rate and without additional introductions. These findings represent one of the first attempts to use optimal channel networks simulation in R to predict the meta-population dynamics of aquatic invasive species, a potential key tool to prevent invasive species spread

    Cardiac interstitial cells express GATA4 and control dedifferentiation and cell cycle re-entry of adult cardiomyocytes.

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    Interstitial cells of the adult rat heart were characterized with respect to i) expression of cardiac markers of commitment and differentiation, ii) myogenic potential in vitro and iii) ability to modulate cardiomyocyte differentiation state. We demonstrate for the first time that fibroblasts and a proportion of pericytes in the adult rat heart express the transcription factor GATA4. This appears to be a peculiar property of the heart. Fibroblasts that are also derived from the splanchnopleuric mesoderm, such as those of the gut, or fibroblasts of different embryological origin, such as those of skin and skeletal muscle, lack this property. Of note, a nestin+/GATA4+ putative stem cell population is also detected in the adult heart. GATA4+ cardiac interstitial cells do not display myogenic potential in vitro. However, cardiac fibroblasts, but not skin fibroblasts, stimulate dedifferentiation of adult cardiomyocytes and their re-entry into the cell cycle in vitro, as demonstrated by the high number of cardiomyocytes expressing Ki67, phosphorylated histone H3 (H3P) and incorporating 5-bromodeoxiuridine (BrdU) in the co-cultures. In conclusion, cardiac fibroblasts have peculiar expression of myogenic transcription factors, a property that may have an impact for reprogramming these cells to the myogenic differentiation. In addition, they are able to modulate the behavior of adult cardiomyocytes, a property that may be used to promote dedifferentiation and proliferation of cardiac cells in the damaged myocardium

    Un singolare caso di ipomagnesemia.

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    An old man with previous resections of small intestine for infarction and sigmoid for adenocarcinoma presented vomit, vertigo, visual impairment, fatigue, serum non detectable, reduced cellular magnesium, no ECG alterations. For the lack of symptoms proportionate to this alteration, an adaptation to progressive decrease in cellular magnesium is hypothesized
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