bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contact Lenses for Color Vision Deficiency
Authors: Elsherif Mohamed , Salih Ahmed E. , Yetisen Ali K. , Butt Haider 
Published: November 2020

AbstractColor blindness or color vision deficiency (CVD) affects around 4.5% of the population in Europe. There have been several attempts to assist color‐blind individuals using color filter glasses. Here, contact lenses are developed to assist individuals suffering from color blindness. Two dyes (Atto 488 and 565) that provide the desired absorption wavelength ranges are selected to be immobilized in soft contact lenses. The chosen dyes have absorption bands in wavelength ranges of 480–500 and 550–580 nm. Both dyes are individually immobilized in contact lenses, and over 95% of the light in the undesired ranges are blocked. The dyes do not diffuse out from lenses in artificial tears and contact lens storage solution. Performances of the developed contact lenses are compared to commercial color‐blind glasses. The contact lenses are tested in color vision deficient patients using Ishihara test. Participants indicate enhancement in the visibility of the colors and their contrast in a color rich environment. The proposed contact lenses show enhanced results as compared to commercial color‐blind glasses in indoors and achieved similar outcomes outdoors.
Threat to the Throne: Can Two Cooperating Boron Atoms Rival Transition Metals in Chemical Bond Activation and Catalysis?
Authors: Prey Sven E. , Wagner Matthias 
Published: November 2020

AbstractCertain electron‐rich 1,4‐diborabenzene derivatives efficiently activate single, double, and triple bonds and thereby increasingly compete with transition metals in homogeneous catalysis. This review compares the activation of three model substrates (H2, H2C=CH2, CO2) by (i) 9,10‐dihydro‐9,10‐diboraanthracene dianions, (ii) their neutral carbene‐stabilized congeners, (iii) 1,3,2,5‐diazadiborinines, and (iv) 1,4,2,5‐diazadiborinines. Distinct structure‐properties relationships become apparent, the most influential factors being (i) the steric demands of the B‐bonded substituents, (ii) the charges on the B‐doped (hetero)arenes, (iii) charge polarization as a result of additional N‐doping, and (iv) the energies and nodal structures of the frontier orbitals. The observed reactions are explained by a transition metal‐like activation mechanism. If the two boron atoms are chemically inequivalent, contributions of a B(+I)/B(+III) mixed‐valence state determine the observed regioselectivities when polar substrates are added. The lessons learned from the conversions of the model substrates are subsequently used to rationalize the behavior of the B2 heterocycles also toward more sophisticated substrate molecules. Finally, catalytic cycles based on H2‐ and H−‐transfers, hydroboration reactions, and CO2 reductions will be covered.magnified image
Ethyl 2‐Cyano‐2‐(2‐nitrobenzenesulfonyloxyimino) Acetate (ortho‐NosylOXY)‐Mediated Double Beckmann Rearrangement of Ketoximes under Microwave Irradiation: A Mechanistic Perception
Authors: Dev Dharm , Kalita Tapasi , Mondal Tanmay , Mandal Bhubaneswar 
Published: November 2020

AbstractA method for Beckmann rearrangement using ethyl 2‐cyano‐2‐(2‐nitrobenzenesulfonyloxyimino) acetate (o‐NosylOXY) under microwave irradiation is reported. Ketoximes (19 examples) are converted to the corresponding amides/lactams with 69–97% yields in ∼10 minutes without any Lewis acid or co‐catalyst. This is an example of halogen‐free organocatalytic Beckmann rearrangement. Nuclear magnetic resonance (NMR)‐ and high‐resolution mass spectrometry (HRMS)‐based detailed mechanistic investigation suggest that o‐NosylOXY acts as an initiator. Such initiators are reported before based on density functional theory (DFT) calculations. However, we report here the HRMS signatures of two transient intermediates, the nitrilium ion and the nitrilium ion's dimeric species. Rigorous NMR‐based investigation of the reaction mechanism is performed. Our results indicate that the reported Beckmann rearrangement proceeds via two consecutive rearrangements.magnified image
Molecular Cages Self‐Assembled by Imine Condensation in Water
Authors: Lei Ye , Chen Qiong , Liu Peiren , Wang Lingxiang , Wang Hongye , Li Bingda , Lu Xingyu , Chen Zhong , Pan Yuanjiang , Huang Feihe , Li Hao 
Published: November 2020

AbstractSelf‐assembly by imine condensation in aqueous media is a formidable task because of the labile nature of imines in the presence of water. Here, by taking advantage of multivalence and ligand preorganization, basket‐shaped triscationic cage molecules are self‐assembled in high yields in both water and organic solvent, by condensing a hexaformyl and bisamine. These cages, especially the chiral ones, are stable or inert in aqueous solution, that is, no decomposition was observed upon dilution, precipitation, or exposure to competitive amines or aldehydes. Such water‐compatibility allows the hosts to take advantage of the hydrophobic effect to accommodate hydrophobic guests. The chiral cage S‐23+ selectively binds and distinguishes one of two enantiomers, opening up opportunities for applications such as chiral compound separation. Chiral narcissistic self‐sorting and sergeants‐and‐soldiers effects occur during cage formation when two amino precursors are involved in self‐assembly.
Nickel‐Catalyzed C‐Heteroatom Cross‐Coupling Reactions under Mild Conditions via Facilitated Reductive Elimination
Authors: Zhu Chen , Yue Huifeng , Jia Jiaqi , Rueping Magnus 
Published: November 2020

AbstractThe formation of C‐heteroatom bonds represents an important type of bond‐forming reaction in organic synthesis and often provides a fast and efficient access to privileged structures found in pharmaceuticals, agrochemical and materials. In contrast to conventional Pd‐ or Cu‐catalyzed C‐heteroatom cross‐couplings under high‐temperature conditions, recent advances in homo‐ and heterogeneous Ni‐catalyzed C‐heteroatom formations under mild conditions are particularly attractive from the standpoint of sustainability and practicability. The generation of NiIII and excited NiII intermediates facilitate the reductive elimination step to achieve mild cross‐couplings. This review provides an overview of the state‐of‐the‐art approaches for mild C‐heteroatom bond formations and highlights the developments in photoredox and nickel dual catalysis involving SET and energy transfer processes; photoexcited nickel catalysis; electro and nickel dual catalysis; heterogeneous photoredox and nickel dual catalysis involving graphitic carbon nitride (mpg‐CN), metal organic frameworks (MOFs) or semiconductor quantum dots (QDs); as well as more conventional zinc and nickel dual catalyzed reactions.
Criegee‐Intermediate über die Ozonolyse hinaus: Ein Einblick in Synthesen und Mechanismen
Authors: Hassan Zahid , Stahlberger Mareen , Rosenbaum Nicolai , Bräse Stefan 
Published: November 2020

AbstractMehr als 70 Jahre nach der Entdeckung sind die “Criegee‐Intermediate” (CIs) wieder an der Spitze der modernen Chemie kurzlebiger reaktiver Zwischenprodukte angelangt. Sie spielen eine wichtige Rolle im mechanistischen Kontext von chemischer Synthese, Totalsynthese, Pharmazeutika und vor allem von klimaregulierender Aerosolbildung sowie der Atmosphärenchemie. Diese Zusammenfassung beinhaltet Schlüsselaspekte von CIs (vom Bildungsmechanismus z. B. über die Ozonolyse von Alkenen und die Photolysemethode, bei der Diiod‐ und Diazoverbindungen verwendet werden, bis hin zu ihren elektronischen Strukturen und ihrer chemischen Reaktivität) und hebt neben den neusten Erkenntnissen einige bahnbrechende Ergebnisse der Gasphasenkinetik sowie deren Nachweise/Messungen hervor. Die jüngsten Fortschritte bei synthetischen und mechanistischen Studien in der Chemie der CIs bieten einen Leitfaden für weitere Untersuchungen auf diesem spannenden Gebiet.
Mixed Group 14–15 Metalates as Model Compounds for Doped Lead Halide Perovskites
Authors: Dehnhardt Natalie , Luy Jan‐Niclas , Klement Philip , Schipplick Luca , Chatterjee Sangam , Tonner Ralf , Heine Johanna 
Published: November 2020

AbstractDoping and alloying are valuable tools for modifying and enhancing the properties and performance of lead halide perovskites. However, the effects of heterovalent doping with Sb3+ and Bi3+ cations are still a matter of current investigation. Due to the different charge of the dopants compared to the constituting Pb2+ ions, a simultaneous creation of defects is unavoidable and the influence of these defects and the actual metal substitution become entangled. Herein, we present the first 14–15 iodido metalates, (BED)4PbE2I16 (BED=N‐benzylethylenediammonium; E=Sb (1), Bi (2)), which are model compounds for doped lead iodide perovskites and display surprisingly low band gaps of 2.01 (1) and 1.88 eV (2). Quantum chemical investigations show that this stems from a good electronic match between the PbI6 and EI6 units of the compounds. Our results provide a model system for doped perovskites, but also represent the first examples of a promising new class of metal halide materials.
Criegee Intermediates Beyond Ozonolysis: Synthetic and Mechanistic Insights
Authors: Hassan Zahid , Stahlberger Mareen , Rosenbaum Nicolai , Bräse Stefan 
Published: November 2020

AbstractAfter more than 70 years since their discovery, Criegee intermediates (CIs) are back at the forefront of modern chemistry of short‐lived reactive intermediates. They play an important role in the mechanistic context of chemical synthesis, total synthesis, pharmaceuticals, and, most importantly, climate‐controlling aerosol formation as well as atmospheric chemistry. This Minireview summarizes key aspects of CIs (from the mechanism of formation, for example, by ozonolysis of alkenes and photolysis methods employing diiodo and diazo compounds, to their electronic structures and chemical reactivity), highlights the most recent findings and some landmark results of gas‐phase kinetics, and detection/measurements. The recent progress in synthetic and mechanistic studies in the chemistry of CIs provides a guide to illustrate the possibilities for further investigations in this exciting field.
Efficient Assay for the Detection of Hydrogen Peroxide by Estimating Enzyme Promiscuous Activity in the Perhydrolysis Reaction
Authors: Wilk Monika , Ostaszewski Ryszard 
Published: November 2020

AbstractHydrogen peroxide is an ideal oxidant in view of its availability, atom economy, or green aspects. Furthermore, it is produced by the cell mitochondria and plays a meaningful role in controlling physiological processes, but its unregulated production leads to the destruction of organs. Due to its diverse roles, a fast and selective method for hydrogen peroxide detection is the major limitation to preventing the negative effects caused by its excess. Therefore, we aimed to develop an efficient assay for the detection of H2O2. For this purpose, we combined the enzymatic method for the detection of hydrogen peroxide with the estimation of the promiscuity of various enzymes. We estimated the activity of an enzyme in the reaction of p‐nitrophenyl esters with hydrogen peroxide resulting in the formation of peracid. To our knowledge, there is no example of a simple, multi‐sensor demonstrating the promiscuous activity of an enzyme and detecting hydrogen peroxide in aqueous media.
Bis‐conjugation of Bioactive Molecules to Cisplatin‐like Complexes through (2,2′‐Bipyridine)‐4,4′‐Dicarboxylic Acid with Optimal Cytotoxicity Profile Provided by the Combination Ethacrynic Acid/Flurbiprofen
Authors: Biancalana Lorenzo , Batchelor Lucinda K. , Pereira Sarah A. P. , Tseng Po‐Jen , Zacchini Stefano , Pampaloni Guido , Saraiva Lúcia M. F. S. , Dyson Paul J. , Marchetti Fabio 
Published: November 2020

AbstractA facile route to PtII complexes doubly functionalized with bioactive molecules through a bipyridine‐type ligand is described. Initially, ligands LEE (containing two ethacrynic acid units), LEF (ethacrynic acid+flurbiprofen) and LEB (ethacrynic acid+biotin) were obtained in moderate to good yields from 2,2′‐bipyridine‐4,4′‐dicarboxylic acid. Subsequent reaction of the ligands with [PtCl2(DMSO)2] afforded complexes [PtCl2(LEE)] (2), [PtCl2(LEF)] (3) and [PtCl2(LEB)] (4) in high yields. All compounds were fully characterized by analytical and spectroscopic methods. Complexes 2–4 are highly stable in water/DMSO solution at 37 °C after 72 h, whereas progressive release of the bioactive fragments was detected in a cell culture medium. The compounds were assessed for their in vitro antiproliferative activity towards tumorigenic A2780, A2780cisR and Y79 cells and non‐tumourigenic HEK293 cells. In particular, the combination of ethacrynic acid and flurbiprofen in 3 overcomes cisplatin‐based resistance and provides strong cancer cell selectivity. Enzyme inhibition assays on human GST P1 and human COX‐2 and cross‐experiments with complex 1, analogous to 2–4 but lacking bio‐groups, revealed a clear synergy between the PtII frame and the bioactive organic components.
Dithieno[a,e]pentalenes: Highly Antiaromatic Yet Stable π‐Electron Systems without Bulky Substituents
Authors: Usuba Junichi , Hayakawa Masahiro , Yamaguchi Shigehiro , Fukazawa Aiko 
Published: November 2020

AbstractInvited for the cover of this issue are Aiko Fukazawa and co‐workers at Kyoto University and Nagoya University. The image depicts the π‐electrons as people to highlight the effect of fused aromatic rings in the antiaromatic π‐electron systems. Read the full text of the article at 10.1002/chem.202004244.
Second‐Generation Biofuels
Authors: Wilke Timm 
Published: November 2020

ZusammenfassungUngeachtet des Wandels zur Elektromobilität werden konventionelle Kraftstoffe noch auf Jahrzehnte hinaus von großer Bedeutung für die weltweite Mobilität sein. Im Beitrag wird ein Unterrichtsprojekt präsentiert, welches mit einem neuen Ansatz an diese Problemstellung anknüpfen soll. In diesem Rahmen identifizieren Schüler zunächst ethisch unproblematische Biomassequellen (z. B. Pflanzenabfälle) und erarbeiten unter Bezugnahme auf aktuelle fachwissenschaftliche und fachdidaktische Veröffentlichungen Möglichkeiten, hieraus Oktan zu gewinnen. Anschließend werden diese Hypothesen innerhalb einer Versuchsreihe umgesetzt. Mit den vorgestellten Schülerexperimenten können die Schüler dabei nicht nur den gesamten Prozess von der Biomasse zum Oktan experimentell nachvollziehen, sondern auch klassische chemische Grundlagen erschließen (Hydrolyse, Redox‐Reaktionen, Elektrolyse) und experimentelle Techniken festigen (Destillation, Extraktion, Filtration). Den Abschluss der Unterrichtseinheit bildet eine kritische Bewertung des Verfahrens im Hinblick auf Zukunftsfähigkeit, Nachhaltigkeit und Bedeutung, was beispielsweise fächerübergreifend im Rahmen eines WebQuests erfolgen kann.
Obinutuzumab‐related adverse events: A systematic review and meta‐analysis
Authors: Amitai Irina , Gafter‐Gvili Anat , Shargian‐Alon Liat , Raanani Pia , Gurion Ronit 
Published: November 2020

ABSTRACTRituximab, the first anti‐CD20 monoclonal antibody, has dramatically improved outcomes for patients with B‐cell lymphoproliferative disorders. Obinutuzumab was developed to potentiate activity and overcome resistance to rituximab. Clinical data suggest that obinutuzumab is superior to rituximab in follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). Yet, it has increased toxicity. This systematic review and meta‐analysis compiled all randomized controlled trials (RCTs) comparing obinutuzumab‐based regimens with rituximab‐based regimens to better assess their toxicity profile. Primary outcome was grade 3–4 infections; secondary outcomes included any adverse events (AE), grade 3–4 AE, drug discontinuation rate, and 3‐years mortality. Relative risks (RRs) were estimated and pooled using a fixed‐effect model, unless there was significant heterogeneity, in which case a random‐effects model was used. Our comprehensive search yielded five RCTs conducted between 2009 and 2014, including 4247 patients. The trials included FL patients, CLL and diffuse large B cell lymphoma. Monoclonal antibodies were given with different chemotherapy regimens (in four trials) or as monotherapy (in one trial). The point estimate favored increase in both grade 3–4 infections rate (RR 1.17 [95% CI, 1.0–1.36]) and any AE rate (RR 1.05 [95% 1–1.1]) with obinutuzumab, although this was not statistically significant. There was a significantly increased rate of grade 3–4 AE (RR 1.15 [95% CI, 1.09–1.2]), as well as grade 3–4 toxicities including thrombocytopenia (RR 2.8 [95% CI, 1.92–4.06]), infusion related reactions (RR 2.8 [95% CI, 2.16‐3.64]) and cardiac events (RR 1.65 [95% CI, 1.11‐2.46]). There was no significant difference in grade 3–4 anemia and neutropenia nor in the 3‐year mortality rate. The point estimate favored increase in discontinuation rate due to AE with obinutuzumab, although without statistical significance (RR 1.24 [95% CI, 1.0–1.54]). In conclusion, physicians need to weigh the clinical benefits of this agent against higher toxicity.
Implications of the overconfidence bias in presence of private information: Evidence from MENA stock markets
Authors: Boussaidi Ramzi 
Published: November 2020

AbstractThis paper extends the empirical literature on overconfidence by investigating the implications of this bias on the trading activity and the market volatility for different levels of private information. Using individual data for 10 MENA stock markets, we found a positive unidirectional causal relation from market return to trading volume in most markets, indicating that overconfident investors attribute past market gains to their own talent in selecting securities and trade later as if they had generated these gains. Consistent with the hypothesis of the investors' overreaction to private information, we found that the trading activity becomes more excessive as the level of private information increases. Moreover, the overconfidence helps explain the observed excessive volatility in presence of high level of private information.
Temperature changes and elevation‐warming relationships in the Carpathian Mountains
Authors: Micu Dana Magdalena , Dumitrescu Alexandru , Cheval Sorin , Nita Ion‐Andrei , Birsan Marius‐Victor 
Published: November 2020

AbstractThis paper investigates the elevation‐warming relationships across the Carpathian Mountains, using the 0.1° × 0.1° gridded daily air temperature dataset developed within the CARPATCLIM project, in order to understand the spatial patterns of annual and seasonal temperature trends and test the hypothesis of enhanced warming with elevation. Temperature trend and elevation‐warming analyses were conducted over the 50 years of the dataset (1961–2010). The vertical variations of five key isotherms relevant for the development of cold‐climate weathering, presence of permafrost (−2°C, 0°C, +2°C, +3°C) and spread of forest vegetation (July +10°C) were also examined. The Carpathian Mountains are under visible annual and seasonal warming (stronger in the summer and winter), both daytime and nighttime. The warming process shows a great spatial inhomogeneity, but is more pronounced in the lowlands of the region, generally below 1,000–1,200 m. The correlations between elevation and warming rates across the Carpathians have been found both to be positive and negative, while mostly significant at the 5% level. Evidence of enhanced warming with elevation was found to be related to the minimum temperature increase mostly across the NW and SW Carpathians, at both annual and seasonal scales (winter, summer and spring). Less prominent EDW signals have been identified in the NE, E and S Carpathians (summer), as well as in the NE Carpathians (spring). Parts of the detected temperature trends and EDW signals have been considered to be an effect of the changing atmospheric circulation (i.e. westerly intensification especially in the winter), although other mechanisms and processes could be involved (e.g. snow‐albedo feedbacks in the spring). These results could serve as a reference for further investigations of climate warming effects across the Carpathian Mountains region (e.g. ecological and geomorphic), especially in relation to the augmented summer heat stress (e.g. more frequent heatwaves) and milder winters (e.g. less freezing days).
Clinicopathologic Characteristics of Centrilobular Injury in Pediatric Liver Transplantation
Authors: González Iván A. , Lu Hsiang‐Chih , Alipour Zahra , Kulkarni Sakil S. , Stoll Janis M. , Liss Kim H.H. , Dehner Louis P. , He Mai 
Published: November 2020

Centrilobular injury (CLI) is defined as the presence of perivenular mononuclear inflammation, hepatocyte dropout, and extravasated erythrocytes. In pediatric liver allografts, CLI has been associated with advanced fibrosis and chronic rejection (CR). We sought to better characterize the clinicopathologic features of CLI in the setting of T cell–mediated rejection (TCMR) and its association with complement component 4d (C4d) deposition. A total of 206 posttransplant pediatric patients (491 allograft liver biopsies) were available from 2000 to 2018, of which 63 patients (102 biopsies) showed evidence of TCMR and were included in the study. Of the patients, 35 (55.6%) had CLI on their initial episode of TCMR; those patients with CLI were significantly associated with the type of immunosuppression treatment (P = 0.03), severity of TCMR (P < 0.001), higher gamma‐glutamyltransferase (P = 0.01), and advanced fibrosis (P = 0.03). There was a trend to shorter time interval from transplantation to presentation of CLI compared with those without CLI (P = 0.06). No difference was observed in graft or overall survival in the patients with CLI. In 20 patients with CLI, additional biopsies were available; in 45% of these patients, CLI was a persistent/recurrent finding. C4d deposition was noted in 12% of all biopsies (6 patients) with CLI. No significant correlation was noted in C4d deposition and CLI, CR, or graft/overall survival. In conclusion, CLI, although not significantly associated with worse graft survival, was significantly associated with severe TCMR and degree of fibrosis, which highlights the importance of active clinical management and follow‐up for these patients.