New fullerene derivatives for the photovoltaic application

Cyclopropano[70]fullerenes have been synthesized in the aim of being used as acceptors in blends based on regioregular poly (3,5-Hexylthiophene) RR-P3HT for photovoltaic (PV) plastic cells. These molecules used with RR-P3HT in bulk heterojunction (BHJ) configuration provided interesting characteristics: 1.5% solar conversion efficiency, 9.29 mA/cm² current density, 0.51 V open circuit voltage, and 0.34 fill factor. The IPCE spectrum for P3HT: cyclopropano[70]fullerene cells shows a peak around 430 nm with 71% external quantum efficiency. This result justifies the increased current density

Dibenzo[ f,h]furazano[3,4- b]quinoxalines: Synthesis by Intramolecular Cyclization through Direct Transition Metal-Free C-H Functionalization and Electrochemical, Photophysical, and Charge Mobility Characterization

Herein, we describe the synthesis of unsymmetrically substituted dibenzo[f,h]furazano[3,4-b]quinoxalines by intramolecular cyclization through direct transition metal-free C-H functionalization. The electrochemical and photophysical properties for several polycycles have been measured. In thin films of the dibenzo[f,h]furazano[3,4-b]quinoxalines, hole mobility is in the order of 10-4 cm2 V-1 s-1. The results show that the HOMO and LUMO energy levels are appropriate for using the compounds as hole-transport materials in thin-film devices, in particular, organic and perovskite solar cells. Copyright © 2020 American Chemical Society.Russian Foundation for Basic Research, RFBR: 18-33-00103-mol_aRussian Science Foundation, RSF: 18-13-00409The research was financially supported by the Russian Science Foundation (project no. 18-13-00409). Y.A.K would like to acknowledge the financial support for the part of the synthetic section from the Russian Foundation for Basic Research (research project no. 18-33-00103-mol_a). The authors are grateful to Grigory A. Kim for carrying out the DFT calculations, which were performed by using “Uran” supercomputer of the Institute of Mathematics and Mechanics of the Ural Branch of the Russian Academy of Sciences. NMR experiments were carried out by using equipment of the Center for Joint Use “Spectroscopy and Analysis of Organic Compounds” at the Postovsky Institute of Organic Synthesis of the Ural Branch of the Russian Academy of Sciences

Diquat Derivatives: Highly Active, Two-Dimensional Nonlinear Optical Chromophores with Potential Redox Switchability

In this article, we present a detailed study of structure−activity relationships in diquaternized 2,2′-bipyridyl (diquat) derivatives. Sixteen new chromophores have been synthesized, with variations in the amino electron donor substituents, π-conjugated bridge, and alkyl diquaternizing unit. Our aim is to combine very large, two-dimensional (2D) quadratic nonlinear optical (NLO) responses with reversible redox chemistry. The chromophores have been characterized as their PF_6^− salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Their visible absorption spectra are dominated by intense π → π^* intramolecular charge-transfer (ICT) bands, and all show two reversible diquat-based reductions. First hyperpolarizabilities β have been measured by using hyper-Rayleigh scattering with an 800 nm laser, and Stark spectroscopy of the ICT bands affords estimated static first hyperpolarizabilities β_0. The directly and indirectly derived β values are large and increase with the extent of π-conjugation and electron donor strength. Extending the quaternizing alkyl linkage always increases the ICT energy and decreases the E_(1/2) values for diquat reduction, but a compensating increase in the ICT intensity prevents significant decreases in Stark-based β_0 responses. Nine single-crystal X-ray structures have also been obtained. Time-dependent density functional theory clarifies the molecular electronic/optical properties, and finite field calculations agree with polarized HRS data in that the NLO responses of the disubstituted species are dominated by ‘off-diagonal’ β_(zyy) components. The most significant findings of these studies are: (i) β_0 values as much as 6 times that of the chromophore in the technologically important material (E)-4′-(dimethylamino)-N-methyl-4-stilbazolium tosylate; (ii) reversible electrochemistry that offers potential for redox-switching of optical properties over multiple states; (iii) strongly 2D NLO responses that may be exploited for novel practical applications; (iv) a new polar material, suitable for bulk NLO behavior

Benzo[ b]selenophene/thieno[3,2- b]indole-Based N,S,Se-Heteroacenes for Hole-Transporting Layers

Two series of new N,S,Se-heteroacenes, namely, 6H-benzo[4′,5′]selenopheno[2′,3′:4,5]thieno[3,2-b]indoles and 12H-benzo[4″,5″]selenopheno[2″,3″:4′,5′]thieno[2′,3′4,5]thieno[3,2-b]indoles, were successfully obtained using an effective strategy based on Fiesselmann thiophene and Fischer indole synthesis. The new molecules exhibit a large optical band gap (2.82 eV < Egopt < 3.23 eV) and their highest occupied molecular orbital (HOMO) energy formed by the plane π-core ranges between -5.2 and -5.6 eV, with the narrower optical band gap and lower HOMO level corresponding to selenated heteroacenes. In thin solid films of the heteroacenes, hole mobility measured using the conventional CELIV technique ranges between 10-5 and 10-4 cm2·V-1·s-1. All these make the proposed condensed-ring compounds a promising platform for the development of hole-transporting materials applicable in organic electronics. Copyright © 2020 American Chemical Society.The research (synthesis of new heteroacenes and investigation of their semiconductor properties) was financially supported by the Russian Science Foundation (project no. 18-13-00409). N.S.D. and N.A.R. would like to acknowledge the financial support for the analytical studies of synthesized compounds from the Ministry of Education and Science of the Russian Federation within the framework of the State Assignment for Research (project no. AAAA-A19-119012490006-1). The authors are grateful to Grigory A. Kim for carrying out the DFT calculations which were performed using ⟨⟨Uran⟩⟩ supercomputer of the Institute of Mathematic and Mechanics of the Ural Branch of the Russian Academy of Sciences. The XRD measurements were performed using the equipment of CKP FMI IPCE RAS

Besides Purkinje cells and granule neurons: an appraisal of the cell biology of the interneurons of the cerebellar cortex

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Parathyroidectomy and survival in a cohort of Italian dialysis patients: results of a multicenter, observational, prospective study

Background: Severe secondary hyperparathyroidism (SHPT)&nbsp;is associated with mortality in end stage kidney disease (ESKD). Parathyroidectomy (PTX) becomes necessary when medical therapy fails, thus highlighting the interest to compare biochemical and clinical outcomes of patients receiving either medical treatment or surgery. Methods: We aimed to compare overall survival and biochemical control of hemodialysis patients with severe hyperparathyroidism, treated by surgery or medical&nbsp;therapy&nbsp;followed-up for 36&nbsp;months.&nbsp;Inclusion criteria were age older than 18&nbsp;years, renal failure requiring dialysis treatment (hemodialysis or peritoneal dialysis) and ability to sign the consent form. A control group of&nbsp;418 patients treated in the same centers,&nbsp;who did not undergo parathyroidectomy was selected after matching&nbsp;for&nbsp;age, sex, and dialysis vintage. Results: From 82 Dialysis units in Italy, we prospectively collected data of 257 prevalent patients&nbsp;who underwent parathyroidectomy (age&nbsp;58.2 ± 12.8 years; M/F: 44%/56%, dialysis&nbsp;vintage: 15.5 ± 8.4 years) and of 418 control patients who did not undergo parathyroidectomy (age&nbsp;60.3 ± 14.4 years; M/F 44%/56%; dialysis vintage 11.2 ± 7.6 y). The survival rate was higher in the group&nbsp;that underwent&nbsp;parathyroidectomy (Kaplan–Meier log rank test = 0.002). Univariable analysis (HR 0.556, CI: 0.387–0.800, p = 0.002) and multivariable analysis (HR 0.671, CI:0.465–0.970, p = 0.034), identified parathyroidectomy as a&nbsp;protective factor of overall survival. The prevalence of patients at KDOQI targets for PTH was lower in patients&nbsp;who underwent parathyroidectomy&nbsp;compared to controls (PTX vs non-PTX: PTH &lt; 150&nbsp;pg/ml: 59% vs 21%, p = 0.001; PTH at target: 18% vs 37% p = 0.001; PTH &gt; 300&nbsp;pg/ml 23% vs 42% p = 0.001). The control group received more intensive medical treatment&nbsp;with higher prevalence of vitamin D (65% vs 41%, p = 0.0001), calcimimetics (34% vs 14%, p = 0.0001) and phosphate binders (77% vs 66%,&nbsp;p = 0.002). Conclusions: Our data suggest that parathyroidectomy is associated with survival rate&nbsp;at 36 months, independently of biochemical control. Lower exposure to high PTH levels could represent an advantage in the long term. Graphical abstract: [Figure not available: see fulltext.]

The violent youth of bright and massive cluster galaxies and their maturation over 7 billion years

In this study, we investigate the formation and evolution mechanisms of the brightest cluster galaxies (BCGs) over cosmic time. At high redshift (z ∼ 0.9), we selected BCGs and most massive cluster galaxies (MMCGs) from the Cl1604 supercluster and compared them to low-redshift (z ∼ 0.1) counterparts drawn from the MCXC meta-catalogue, supplemented by Sloan Digital Sky Survey imaging and spectroscopy. We observed striking differences in the morphological, colour, spectral, and stellar mass properties of the BCGs/MMCGs in the two samples. High-redshift BCGs/MMCGs were, in many cases, star-forming, late-type galaxies, with blue broad-band colours, properties largely absent amongst the low-redshift BCGs/MMCGs. The stellar mass of BCGs was found to increase by an average factor of 2.51 ± 0.71 from z ∼ 0.9 to z ∼ 0.1. Through this and other comparisons, we conclude that a combination of major merging (mainly wet or mixed) and in situ star formation are the main mechanisms which build stellar mass in BCGs/MMCGs. The stellar mass growth of the BCGs/MMCGs also appears to grow in lockstep with both the stellar baryonic and total mass of the cluster. Additionally, BCGs/MMCGs were found to grow in size, on average, a factor of ∼3, while their average Sérsic index increased by ∼0.45 from z ∼ 0.9 to z ∼ 0.1, also supporting a scenario involving major merging, though some adiabatic expansion is required. These observational results are compared to both models and simulations to further explore the implications on processes which shape and evolve BCGs/MMCGs over the past ∼7 Gyr