Second international spectroradiometer intercomparison: results and impact on PV device calibration

This paper describes the results of an intercomparison of spectroradiometers for measuring global normal incidence and direct normal incidence spectral irradiance in the visible and in the near infrared, together with an assessment of the impact these results may have on the calibration of the short circuit current (I-sc) of triple-junction photovoltaic devices and on the relevant spectral mismatch calculation. The intercomparison was conducted by six European scientific laboratories and a Japanese industrial partner. Seven spectroradiometer systems, for a total of 13 different instruments/channels using two different technologies and made by four different manufacturers were involved. This group of systems represents a good cross section of the instrumentation for solar spectrum measurements available to date. The instruments were calibrated by each partner prior to the intercomparison following their usual procedure and traceability route in order to verify the entire measurement and traceability chain. The difference in measured spectral irradiance showed to have an impact on the calibration of a set of Iso-Type cells varying from +/- 2% to +/- 14% for middle and bottom cell, respectively

Second international spectroradiometer intercomparison: preliminary results and impact on PV device calibration

This paper describes the preliminary results of an intercomparison of spectroradiometers for global (GNI) and direct normal incidence (DNI) irradiance in the visible (VIS) and near infrared (NIR) spectral regions together with an assessment of the impact these results may have on the calibration of triple-junction photovoltaic devices and on the relevant spectral mismatch calculation. The intercomparison was conducted by six European scientific laboratories and a Japanese industrial partner. Seven institutions and seven spectroradiometer systems, representing different technologies and manufacturers were involved, representing a good cross section of the todays available instrumentation for solar spectrum measurements

The Interaction between Reactive Peritoneal Mesothelial Cells and Tumor Cells via Extracellular Vesicles Facilitates Colorectal Cancer Dissemination

Simple SummaryEmerging evidence has suggested that cancer-derived extracellular vesicles (EVs) have a crucial role in mediating directional metastasis to the peritoneal surface in colorectal cancer (CRC). We investigated the EV-mediated crosstalk between tumor and mesothelial cells which may drive remodeling of the premetastatic niche to allow tumor spread to the peritoneal surface. Our findings demonstrated that cancer-derived EVs triggered apoptosis and reduced mesothelial cell invasiveness and mesothelial-to-mesenchymal transition. On the other hand, mesothelial cells actively supported tumor invasion by releasing EVs, which induced upregulation of the major pro-invasive system in tumor cells. For the first time, we provide evidence of EV-driven mechanisms of CRC progression in patient-derived models, highlighting the crucial role of EVs in the reprogramming of mesothelial and tumor cells to establish the metastatic process.Advanced colorectal cancer (CRC) is highly metastatic and often results in peritoneal dissemination. The extracellular vesicles (EVs) released by cancer cells in the microenvironment are important mediators of tumor metastasis. We investigated the contribution of EV-mediated interaction between peritoneal mesothelial cells (MCs) and CRC cells in generating a pro-metastatic environment in the peritoneal cavity. Peritoneal MCs isolated from peritoneal lavage fluids displayed high CD44 expression, substantial mesothelial-to-mesenchymal transition (MMT) and released EVs that both directed tumor invasion and caused reprogramming of secretory profiles by increasing TGF-beta 1 and uPA/uPAR expression and MMP-2/9 activation in tumor cells. Notably, the EVs released by tumor cells induced apoptosis by activating caspase-3, peritoneal MC senescence, and MMT, thereby augmenting the tumor-promoting potential of these cells in the peritoneal cavity. By using pantoprazole, we reduced the biogenesis of EVs and their pro-tumor functions. In conclusion, our findings provided evidence of underlying mechanisms of CRC dissemination driven by the interaction of peritoneal MCs and tumor cells via the EVs released in the peritoneal cavity, which may have important implications for the clinical management of patients

Vitamin C Deficiency in Patients With Acute Myeloid Leukemia

Vitamin C has been shown to play a significant role in suppressing progression of leukemia through epigenetic mechanisms. We aimed to study the role of vitamin C in acute myeloid leukemia (AML) biology and clinical course. To this purpose, the plasma levels of vitamin C at diagnosis in 62 patients with AML (including 5 cases with acute promyelocytic leukemia, APL),7 with myelodysplastic syndrome (MDS), and in 15 healthy donors (HDs) were studied. As controls, vitamins A and E levels were analysed. Expression of the main vitamin C transporters and of the TET2 enzyme were investigated by a specific RQ-PCR while cytoplasmic vitamin C concentration and its uptake were studied in mononuclear cells (MNCs), lymphocytes and blast cells purified from AML samples, and MNCs isolated from HDs. There were no significant differences in vitamin A and E serum levels between patients and HDs. Conversely, vitamin C concentration was significantly lower in AML as compared to HDs (p<0.0001), inversely correlated with peripheral blast-counts (p=0.029), significantly increased at the time of complete remission (CR) (p=0.04) and further decreased in resistant disease (p=0.002). Expression of the main vitamin C transporters SLC23A2, SLC2A1 and SLC2A3 was also significantly reduced in AML compared to HDs. In this line, cytoplasmic vitamin C levels were also significantly lower in AML-MNCs versus HDs, and in sorted blasts compared to normal lymphocytes in individual patients. No association was found between vitamin C plasma levels and the mutation profile of AML patients, as well as when considering cytogenetics or 2017 ELN risk stratification groups. Finally, vitamin C levels did not play a predictive role for overall or relapse-free survival. In conclusion, our study shows that vitamin C levels are significantly decreased in patients with AML at the time of initial diagnosis, further decrease during disease progression and return to normal upon achievement of CR. Correspondingly, low intracellular levels may mirror increased vitamin C metabolic consumption in proliferating AML cells

Roadmap on thermoelectricity

The increasing energy demand and the ever more pressing need for clean technologies of energy conversion pose one of the most urgent and complicated issues of our age. Thermoelectricity, namely the direct conversion of waste heat into electricity, is a promising technique based on a long-standing physical phenomenon, which still has not fully developed its potential, mainly due to the low efficiency of the process. In order to improve the thermoelectric performance, a huge effort is being made by physicists, materials scientists and engineers, with the primary aims of better understanding the fundamental issues ruling the improvement of the thermoelectric figure of merit, and finally building the most efficient thermoelectric devices. In this Roadmap an overview is given about the most recent experimental and computational results obtained within the Italian research community on the optimization of composition and morphology of some thermoelectric materials, as well as on the design of thermoelectric and hybrid thermoelectric/photovoltaic devices

Sintesi di analoghi del resveratrolo quali potenziali stabilizzatori della transtiretina nativa

Il contenuto di questa relazione è strettamente riservato, essendo presenti argomenti tutelati dalla legge come segreti. Pertanto tutti coloro che ne prendono conoscenza sono soggetti all'obbligo, sanzionato anche penalmente dagli articoli 325 e 623 del codice penale, di non divulgare e di non utilizzare le informazioni acquisite La Transtiretina è una proteina di 55 KDa costituita da 4 subunità identiche formate da 127 aa ciascuna. Per le sue somiglianze con l’albumina è definita anche pre-albumina. È presente in diverse specie animali tra cui mammiferi, volatili e rettili . Questa proteina è sintetizzata principalmente dal fegato ma anche, seppur in minor quantità, dal plesso corioideo nel cervello, dalla retina e dalla placenta. In condizione fisiologiche la transtiretina è solubile e circola nel sangue e nel liquido cerebrospinale (a diverse concentrazioni) con il ruolo di trasportatore di Tiroxina e Retinolo (Vitamina A). Quest’ultimo è trasportato attraverso la sua associazione con la proteina chaperone RBP. Da ciò il suo acronimo TTR: trasporter, thyroxine and Retinol . La struttura quaternaria della proteina possiede due siti di legame imbutiformi, situati all’interfaccia dimero-dimero A,B/C,D che legano la Tiroxina. Ciascuno dei due siti di legame è formato da due sottositi, ognuno dei quali è costituito da: una piccola tasca di legame che guarda verso l’interno (inner binding pocket) ed una larga tasca di legame che guarda verso l’esterno (Outer binding pocket). Nelle suddette subunità vi sono tre depressioni che rappresentano le tasche di legame per l’interazione degli atomi di iodio del ligando endogeno (HBPs). Tuttavia, anche se ogni TTR può potenzialmente trasportare 2 molecole di ormone tiroideo, queste si ritrovano in circolo saturate solo in piccola parte. Ciò è dovuto al fatto che nel sangue circolano altre proteine, come la globulina legante la tiroxina (TBG) e l’albumina, che legano l’ormone, già presente in quantità molto basse . Per cause non note, il tetramero della transtiretina si dissocia e riassociandosi modifica la sua forma nativa e forma delle fibrille amiloidi insolubili che si depositano a livello di organi e tessuti, compromettendone la funzionalità. Il deposito di proteine insolubili in organi e/o tessuti costituisce un’amiloidosi. Le amiloidosi conosciute riguardano più di 30 proteine sieriche e tra le più conosciute e studiate, seppur considerate delle patologie rare fino a pochi anni fa, vi sono le amiloidosi da transtiretina. Queste si distinguono in ereditarie e non ereditarie. Tra queste ultime figura l’amiloidosi sistemica senile (SSA), che è età dipendente, insorge tra i 60 e 70 anni ed interessa principalmente il cuore. Nella SSA si può avere anche un interessamento intestinale o tunnel carpale. In questa forma è coinvolta la transtiretina wild-type (TTR nativa). Invece tra le forme ereditarie, dovute a singole mutazioni puntiformi della TTR, distinguiamo: - La polineuropatia amiloide familiare (FAP), che coinvolge principalmente il sistema nervoso periferico. - L’amiloidosi cardiaca familiare (FAC), che coinvolge principalmente il cuore. - L’amiloidosi selettiva del SNC (CNSA), che coinvolge principalmente il sistema nervoso centrale. In passato per il trattamento di queste patologie veniva utilizzato il trapianto di fegato, principale fonte di TTR. Questa metodologia presenta dei rischi e, inoltre, può risultare inefficace in alcuni tipi di amiloidosi da TTR dal momento che non è l’unica fonte di transtiretina. Il trattamento che sta emergendo negli ultimi anni riguarda l’utilizzo di piccole molecole che vanno a legarsi e stabilizzare il tetramero. Questa deduzione è derivata dal fatto che è stato visto che la tiroxina, ligando endogeno, è in grado di stabilizzare la TTR. Possiamo distinguere i composti che stabilizzano la TTR in: analoghi di ormoni tiroidei, composti non naturali e composti naturali. Per quanto concerne i composti non naturali bisogna fare accezione a due composti entrati in fase clinica che sono il Diflunisal e il Tafamidis. Il primo è un farmaco antinfiammatorio non stereoideo in trial clinico approvato da FDA che possiede però diversi effetti collaterali legati all’inibizione delle prostaglandine. Il Tafamidis, al contrario non ha ottenuto l’approvazione della agenzia americana, ma è stato approvato da EMA e PMDA per il trattamento della FAP nel primo stadio. Recenti studi su molecole naturali a struttura polifenolica presenti nell’alimentazione mediterranea hanno dimostrato che sono in grado di dare beneficio in diverse patologie a carattere amiloide. Nello specifico, composti come l’oleuropeina (olive) , epigallocatechina 3-gallato (the verde) e resveratrolo (vino rosso) possono donare benefici per varie patologie a carattere degenerativo, tra cui le amiloidosi da transtiretina. In questo elaborato di tesi il nostro interesse si è rivolto verso il resveratrolo: una molecola di natura stilbenica dotata, oltre che di un’attività stabilizzatrice la TTR, anche di un’attività antiossidante. Il resveratrolo ha rappresentato la nostra molecola lead. Sono stati sintetizzati una serie di composti resveratrolo-like, in cui il linker insaturo fra le due porzioni aromatiche è stato sostituito con un liker più flessibile di natura eteroatomica. I composti sintetizzati sono stati caratterizzati per mezzo di spettroscopia 1H-NMR e valutati attraverso un saggio turbidimetrico in vitro UV-vis che consente di valutare la capacità delle molecole sintetizzate di inibire la formazione di fibrille comparandole con il Diflunisal, scelto come farmaco di riferimento che è in grado di inibire la formazione di fibrille fino al 97 %

Resveratrol-like Compounds as SIRT1 Activators

The sirtuin 1 (SIRT1) activator resveratrol has emerged as a promising candidate for the prevention of vascular oxidative stress, which is a trigger for endothelial dysfunction. However, its clinical use is limited by low oral bioavailability. In this work, we have applied a previously developed computational protocol to identify the most promising derivatives from our in-house chemical library of resveratrol derivatives. The most promising compounds in terms of SIRT1 activation and oral bioavailability, predicted in silico, were evaluated for their ability to activate the isolated SIRT1 enzyme. Then, we assessed the antioxidant effects of the most effective derivative, compound 3d, in human umbilical vein endothelial cells (HUVECs) injured with H2O2 100 µM. The SIRT1 activator 3d significantly preserved cell viability and prevented an intracellular reactive oxygen species increase in HUVECs exposed to the oxidative stimulus. Such effects were partially reduced in the presence of a sirtuin inhibitor, sirtinol, confirming the potential role of sirtuins in the activity of resveratrol and its derivatives. Although 3d appeared less effective than resveratrol in activating the isolated enzyme, the effects exhibited by both compounds in HUVECs were almost superimposable, suggesting a higher ability of 3d to cross cell membranes and activate the intracellular target SIRT1

Characterization of High Efficiency c-Si CPV Cells

Concentrating Photovoltaics (CPV) represents an emerging market at its early stage for terrestrial application with large growth expectation and considerable research activity on new cells production has been conducting recently. As response to a fast growing demand for traceable and independent measurements on CPV cells and systems the European Solar Test Installation (ESTI) has started a research program on indoor/outdoor device characterization. This paper focuses on the results of an intercomparison of procedures and experimental setup for concentrating c-Si cell characterization held at ESTI and at the UTTP FOTO Laboratory of ENEA. Current voltage curves, short-circuit current and efficiency measurements have been performed at high intensities on three different setups: a recently developed 1500X pulsed solar simulator at ESTI and two modified solar simulators capable of achieving up to 250X concentration at ENEA. Reference c-Si cells equipped with neutral density filters of various optical densities have been used at ESTI for checking the linearity of cells under test at different concentration ratios. First results show the agreement within measurement uncertainties of the electrical parameters.JRC.DDG.F.8-Renewable Energy (Ispra

Extending the Spectrum Characterisation of Solar Simulators from 300 nm to 1200 nm: Challenges on Spectral Measurements in the UV and NIR

Innovative photovoltaic technologies with spectral sensitivity exceeding the 400 to 1100 nm limits (as currently defined by the international standard IEC 60904-9) are nowadays available on the market. This poses new challenges in the correct measurement of the spectral content of solar simulators and natural sunlight in those wavelength bands that lie outside these limits. This study proposes an extension of the IEC 60904-9 bandwidth by adding two bands in the UV (300-400 nm) and NIR (1100-1200 nm) regions. This new proposed extension is analysed in terms of spectral match, using spectral measurements of Global Normal Irradiance (GNI) acquired during the 6th European Spectroradiometer Intercomparison by eight independent laboratories. A laboratory is selected to provide reference spectra, and the spectral match of the other ones is calculated, both on a single-measurement level and on a daily average level. The intra-day and inter-day variations are evaluated as well. Results show that all investigated laboratories are capable to assure a spectral match well below the ±25% limit corresponding to class-A simulators. When the more stringent, informal class-A+ corresponding to the ±12.5% limit is considered, four out of seven laboratories are still compliant with it.JRC.C.2-Energy Efficiency and Renewable