bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die dynamische Wechselwirkung von n‐Butan mit Imidazolium‐basierten ionischen Flüssigkeiten
Authors: Bhuin Radha G. , Winter Leonhard , Lexow Matthias , Maier Florian , Steinrück Hans‐Peter 
Published: May 2020

AbstractDas Auftreffen eines Reaktanten aus der Gasphase auf die Oberfläche einer Flüssigkeit und dessen Transfer durch die Gas/Flüssig‐Grenzfläche sind äußerst wichtig für verschiedene Konzepte in der Katalyse, bei denen ionische Flüssigkeiten (engl. ionic liquids, ILs) verwendet werden. Wir haben daher die Adsorptionsdynamik von n‐Butan auf einer Reihe von 1‐Alkyl‐3‐methyl‐imidazolium‐bis(trifluoromethansulfonyl)imid‐ILs ([CnC1Im][Tf2N]; n=1, 2, 3, 8) mithilfe eines Überschallmolekularstrahls im Ultrahochvakuum auf gefrorenen IL‐Oberflächen in Abhängigkeit der Oberflächentemperatur zwischen 90 und 125 K bestimmt. Auf den C8‐ und C3‐ILs adsorbiert n‐Butan bei 90 K mit einem Anfangshaftfaktor von ≈0.89. Die Adsorptionsenergie steigt mit zunehmender Länge der Alkylseitenkette im Kation, während die ionischen Kopfgruppen anscheinend nur schwach mit n‐Butan wechselwirken. Im Gegensatz dazu findet auf den C1‐ und C2‐ILs keine Adsorption statt. Dies führen wir auf eine zu kurze Verweilzeit auf der IL‐Oberfläche zurück, weshalb selbst bei 90 K keine Kondensationskeime gebildet werden können.
Gold Complexes with Difunctional Perfluoroalkyl Chains: Quantifying the Energy of Aurophilic Interactions in Flexible Open‐Chain Complexes
Authors: Portugués Alejandro , González Lydia , Bautista Delia , Gil‐Rubio Juan 
Published: May 2020

AbstractThe first binuclear AuI compounds containing bridging (CF2)n chains (n=4, 6, 8) and AuIII metallaperfluorocyclopentanes have been obtained by photoinitiated reactions of LAuMe (L=PPh3, PMe3, PCy3, or IPr) with α,ω‐diiodoperfluorocarbons. Complexes LAu(CF2)4AuL present an unusual looped structure stabilized by an aurophilic interaction for L=PMe3, PPh3, and PCy3. The study of their dynamic behaviour has provided new insights about the strength of aurophilic interactions in solution, allowing quantification of the energy of a single Au⋅⋅⋅Au interaction.
High‐Performance All‐Polymer Solar Cells: Synthesis of Polymer Acceptor by a Random Ternary Copolymerization Strategy
Authors: Du Jiaqi , Hu Ke , Meng Lei , Angunawela Indunil , Zhang Jinyuan , Qin Shucheng , Liebman‐Pelaez Alex , Zhu Chenhui , Zhang Zhanjun , Ade Harald , Li Yongfang 
Published: May 2020

AbstractDemonstrated in this work is a simple random ternary copolymerization strategy to synthesize a series of polymer acceptors, PTPBT‐ETx, by polymerizing a small‐molecule acceptor unit modified from Y6 with a thiophene connecting unit and a controlled amount of an 3‐ethylesterthiophene (ET) unit. Compared to PTPBT of only Y6‐like units and thiophene units, PTPBT‐ETx (where x represents the molar ratio of the ET unit) with an incorporated ET unit in the ternary copolymers show up‐shifted LUMO energy levels, increased electron mobilities, and improved blend morphologies in the blend film with the polymer donor PBDB‐T. And the all‐polymer solar cell (all‐PSC) based on PBDB‐T:PTPBT‐ET0.3 achieved a high power conversion efficiency over 12.5 %. In addition, the PTPBT‐ET0.3‐based all‐PSC also exhibits long‐term photostability over 300 hours.
Sustainable synthesis of quinolines (pyridines) catalyzed by a cheap metal Mn(I)‐NN complex catalyst
Authors: Chai Huining , Tan Weiqiang , Lu Yuanyuan , Zhang Guangyao , Ma Jiping 
Published: May 2020

AbstractThis study represents the first example of a bidentate phosphine‐free manganese(I)‐NN complex catalyst for the synthesis of quinolines (pyridines) through acceptorless dehydrogenative condensation of various secondary alcohols with amino alcohols. The coupling reactions occurred at 3 mol% catalyst loading and 110°C, and tolerated diverse functional groups. Moderate to excellent yields ranging from 45% to 89% were achieved after 12 hr of reaction. The present protocol provides a concise and environmentally friendly method for the construction of heterocyclic compounds.
Triazine‐cored dendritic molecules containing multiple o‐carborane clusters
Authors: Jena Bibhuti Bhusan , Jena Soumya Ranjan , Swain Biswa Ranjan , Mahanta Chandra Sekhara , Samanta Luna , Dash Barada P. , Satapathy Rashmirekha 
Published: May 2020

AbstractA series of C3‐symmetricaltriazine‐cored small dendritic molecules containing three to nine peripheral o‐carborane clusters were synthesized through Cu(I)‐catalyzedazide–alkyne cycloaddition reactions. The newly synthesized molecules containing multiple o‐carborane moieties were characterized using nuclear magnetic resonance and matrix‐assisted laser desorption/ionization‐time of flight mass spectral analysis. The biological evaluation of these three to nine cage dendrimers was performed using breast cancer cells (Michigan Cancer Foundation 7). All these dendritic compounds showed cytotoxicity toward breast cancer cells, and the toxicity increased as the number of peripheral o‐carboranes increased. The 9‐cage molecule showed the highest cytotoxicity, and the half maximal inhibitory concentration (IC50) value was found to be 80.67 ng/ml. Its cytotoxicity was significantly higher than the common chemotherapy agent cisplatin. As expected, the boron‐richo‐carborane‐appended molecules showed high thermal stability. The thermal stability increased as the number of peripheral o‐carborane moieties increased.
Alkali Metal–Promoted Facile Synthesis of Secondary Amines from Imines and Carbodiimides
Authors: Panda Tarun K. , Banerjee Indrani , Sagar Shweta 
Published: May 2020

AbstractWe present here an efficient method for the hydroboration of aldimines (‐C=N‐) with pinacolborane (HBpin) using an alkali metal catalyst, potassium benzyl. The reaction was accomplished with unprecedented catalytic efficiency under mild and solvent‐free conditions to afford the high yield of the corresponding N‐boryl amines up to 97%. Various functionalities on aldimines were incorporated for hydroboration. The corresponding boryl amines were subjected to further hydrolysis to yield the corresponding secondary amines with good yields up to 89%. This protocol for the reaction demonstrates an atom‐economic and green method with diverse imines that bears excellent functional group tolerance. Chemoselective reduction of imines was also attained, with good yields of 74–89%. We also propose the most plausible mechanism involving the formation of metal hydride as the active pre‐catalyst.
Near‐Infrared Multipurpose Lanthanide‐Imaging Nanoprobes
Authors: Wang Zhimin , Xing Bengang 
Published: May 2020

AbstractOptical imaging plays a growing role in modern biomedical research and clinical applications due to its high sensitivity, superb spatiotemporal resolution and minimal hazards. Lanthanide‐doped nanoparticles (LDNPs), as a classical category of luminescent materials, exhibit promising photostability, near‐infrared (NIR)‐excited frequency up‐/down‐converting capabilities, emission fine‐tuning and multispectral features, which have greatly promoted the endeavors of deeper and clearer diagnostics in complex living conditions. This review focuses on the recent advances of LDNP‐based multipurpose imaging studies using upconversion, downshifting, lifetime, photoacoustic and multimodal nanoprobes in the NIR (650–1000 nm) and the second near‐infrared window (NIR‐II, 1000–1700 nm). The principle and design of various functional, activatable, multiplexing or multimodal lanthanide‐imaging nanoprobes (LINPs) as well as representative biophotonic applications are summarized in detail. In addition, the future perspectives and challenges for facilitating LINPs to clinical translations are discussed.
Masked observation for majority‐based control of a democratic progress model in the framework of discrete event systems
Authors: Park Seong‐Jin , Yang Jung‐Min 
Published: May 2020

AbstractThis paper addresses a simple democratic progress model represented by a discrete‐event system (DES) and the influence of information accessibility on the progressiveness of the model. Each agent makes a decision according to its selfish criterion, and the final decision for the progress or regression of the system is done by the majority rule based on individual decisions of agents. We first present the conditions for the closed‐loop system to be progressive or regressive under full observation where every agent can observe all the states. Then we focus on the masked observation problem, namely, whether the progressiveness of the closed‐loop behavior can be changed by restricting the information accessibility of agents that are characterized by their masks. Especially, we show that due to the elite class, the regressive closed‐loop system can never be transformed into progressive regardless of mask design, which conforms to the feature of modern democracy.
Thromboembolic and bleeding complications in patients with oesophageal cancer
Authors: Mulder F I , Hovenkamp A , Laarhoven H W M , Büller H R , Kamphuisen P W , Hulshof M C C M , Berge Henegouwen M I , Middeldorp S , Es N 
Published: May 2020

Abstract

Background
In patients who undergo curative treatment for oesophageal cancer, risk estimates of venous thromboembolism (VTE), arterial thromboembolism and bleeding are needed to guide decisions about thromboprophylaxis.

Methods
This was a single-centre, retrospective cohort study of patients with stage I–III oesophageal cancer who received neoadjuvant chemoradiation followed by oesophagectomy. The outcomes VTE, arterial thromboembolism, major bleeding, clinically relevant non-major bleeding and mortality were analysed for four consecutive cancer treatment stages (from diagnosis to neoadjuvant chemoradiotherapy, during neoadjuvant treatment, 30-day postoperative period, and up to 6 months after postoperative period).

Results
Some 511 patients were included. The 2-year survival rate was 67·3 (95 per cent c.i. 63·2 to 71·7) per cent. During the 2-year follow-up, 50 patients (9·8 per cent) developed VTE, 20 (3·9 per cent) arterial thromboembolism, 21 (4·1 per cent) major bleeding and 30 (5·9 per cent) clinically relevant non-major bleeding. The risk of these events was substantial at all treatment stages. Despite 30-day postoperative thromboprophylaxis, 17 patients (3·3 per cent) developed VTE after surgery. Patients with VTE had worse survival (time-varying hazard ratio 1·81, 95 per cent c.i. 1·25 to 2·64). Most bleeding events occurred around the time of medical intervention, and approximately one-half during concomitant use of prophylactic or therapeutic anticoagulation.

Conclusion
Patients with oesophageal cancer undergoing neoadjuvant chemoradiotherapy and surgery are at substantial risk of thromboembolic and bleeding events throughout all stages of treatment. Survival is worse in patients with thromboembolic events during follow-up.
Redirection of miRNA‐Argonaute Complexes to Specific Target Sites by Synthetic Adaptor Molecules
Authors: Bolz Mathias , Thomas Laura , Scheffer Ute , Kalden Elisabeth , Hartmann Roland K. , Göbel Michael W. 
Published: May 2020

AbstractDysregulation of miRNAs is connected with a multitude of diseases for which antagomirs and miRNA replacement are discussed as therapeutic options. Here, we suggest an alternative concept based on the redirection of RISCs to non‐native target sites. Metabolically stable DNA‐LNA mixmers are used to mediate the binding of RISCs to mRNAs without any direct base complementarity to the presented guide RNA strand. Physical redirection of a dye‐labeled miRNA model and of specific miRNA‐programmed RISC fractions present in HeLa extracts is demonstrated by pull‐down experiments with biotinylated capture oligonucleotides.
Cutis verticis gyrata: Two cases associated with drug‐resistant epilepsy
Authors: Rattagan Maria , De Francesco Maria , Kriebaum Antonio , Ferraro Fernando , Major Catherine , Sharma Deepak , Ojeda Andrew , Martinez Oscar , Musto Alberto E. 
Published: May 2020

AbstractCutis verticis gyrata (CVG) is a neurocutaneous syndrome characterized by the formation of folds in the scalp that resembles the cerebral cortex. We present two cases of CVG and intellectual disability with drug‐resistant epilepsy. Recognizing CVG is necessary to provide interdisciplinary support for the treatment of comorbidities associated with this entity.
Vanadium Oxide‐Nitride Composites for Catalytic Oxidative C−C Bond Cleavage of Cyclohexanol into Lactones with Dioxygen
Authors: Xiao Chuhong , Du Zhongtian , Li Shaojie , Zhao Yanbin , Liang Changhai 
Published: May 2020

AbstractSelective catalytic oxidative C−C bond cleavage with dioxygen is useful and challenging to prepare oxygenated fine chemicals. Herein we fabricated vanadium oxide–nitride composites as catalysts via a facile thermal treatment process, and the surface composition could be tuned by the thermal treatment temperature, which could affect catalytic oxidation of cyclohexanol significantly. By using such a V−N−C composite prepared at 500 °C, cyclohexanol could be selectively oxidized with dioxygen into lactones including δ‐valerolactone and γ‐butyrolactone, rather than common dicarboxylic acids. Cyclohexanone and 2‐cyclohexen‐1‐one were verified as two key intermediates. V3+ species in the form of vanadium nitride and vanadium (III) oxide were detected, and well dispersed on amorphous carbon with a low degree of graphitization. These findings will provide a reference for catalytic oxidative C−C bond cleavage with molecular oxygen under mild reaction conditions.
Effect of Larger Pore Size on the Sorption Properties of Isoreticular Metal–Organic Frameworks with High Number of Open Metal Sites
Authors: Dietzel Pascal D. C. , Georgiev Peter A. , Frøseth Morten , Johnsen Rune E. , Fjellvåg Helmer , Blom Richard 
Published: May 2020

AbstractFour isostructural CPO‐54‐M metal‐organic frameworks based on the larger organic linker 1,5‐dihydroxynaphthalene‐2,6‐dicarboxylic acid and divalent cations (M=Mn, Mg, Ni, Co) are shown to be isoreticular to the CPO‐27 (MOF‐74) materials. Desolvated CPO‐54‐Mn contains a very high concentration of open metal sites, which has a pronounced effect on the gas adsorption of N2, H2, CO2 and CO. Initial isosteric heats of adsorption are significantly higher than for MOFs without open metal sites and are slightly higher than for CPO‐27. The plateau of high heat of adsorption decreases earlier in CPO‐54‐Mn as a function of loading per mole than in CPO‐27‐Mn. Cluster and periodic density functional theory based calculations of the adsorbate structures and energetics show that the larger adsorption energy at low loadings, when only open metal sites are occupied, is mainly due to larger contribution of dispersive interactions for the materials with the larger, more electron rich bridging ligand.
One‐Pot Synthesis of Enantioenriched β‐Amino Secondary Amides via an Enantioselective [4+2] Cycloaddition Reaction of Vinyl Azides withN‐Acyl Imines Catalyzed by a Chiral Brønsted Acid
Authors: Nakanishi Taishi , Kikuchi Jun , Kaga Atsushi , Chiba Shunsuke , Terada Masahiro 
Published: May 2020

AbstractA catalytic enantioselective synthesis of β‐amino secondary amides was achieved using vinyl azides as the enamine‐type nucleophile and chiralN‐Tf phosphoramide as the chiral Brønsted acid catalyst through a five‐step sequential transformation in one pot. The established sequential transformation involves an enantioselective [4+2] cycloaddition reaction of vinyl azides withN‐acyl imines as the key stereo‐determining step that is efficiently accelerated by a chiralN‐Tf phosphoramide catalyst in a highly enantioselective manner in most cases. Further generation of the iminodiazonium ion intermediate through ring opening of the cycloaddition product and subsequent skeletal rearrangement involving Schmidt‐type 1,2‐aryl group migration followed by recyclization of the resulting nitrilium ion were also initiated by the same acid catalyst. Final acid hydrolysis of the recyclized products in the same pot gave rise to enantioenriched β‐amino amides through C−C bond formation at the α‐position of the secondary amides.
Protein‐Templated Hit Identification through an Ugi Four‐Component Reaction**
Authors: Mancini Federica , Unver M. Yagiz , Elgaher Walid A. M. , Jumde Varsha R. , Alhayek Alaa , Lukat Peer , Herrmann Jennifer , Witte Martin D. , Köck Matthias , Blankenfeldt Wulf , Müller Rolf , Hirsch Anna K. H. 
Published: May 2020

AbstractKinetic target‐guided synthesis represents an efficient hit‐identification strategy, in which the protein assembles its own inhibitors from a pool of complementary building blocks via an irreversible reaction. Herein, we pioneered an in situ Ugi reaction for the identification of novel inhibitors of a model enzyme and binders for an important drug target, namely, the aspartic protease endothiapepsin and the bacterial β‐sliding clamp DnaN, respectively. Highly sensitive mass‐spectrometry methods enabled monitoring of the protein‐templated reaction of four complementary reaction partners, which occurred in a background‐free manner for endothiapepsin or with a clear amplification of two binders in the presence of DnaN. The Ugi products we identified show low micromolar activity on endothiapepsin or moderate affinity for the β‐sliding clamp. We succeeded in expanding the portfolio of chemical reactions and biological targets and demonstrated the efficiency and sensitivity of this approach, which can find application on any drug target.
Self‐Assembly and Biorecognition of a Spirohydantoin Derived from α‐Tetralone: Interplay between Chirality and Intermolecular Interactions
Authors: Lazić Anita M. , Đorđević Ivana S. , Radovanović Lidija D. , Popović Dragan M. , Rogan Jelena R. , Janjić Goran V. , Trišović Nemanja P. 
Published: May 2020

AbstractA racemic spirohydantoin derivative with two aromatic substituents, a tetralin and a 4‐methoxybenzyl unit, was synthesized and its crystal structure was determined. To define the relationship between molecular stereochemistry and spatial association modes, development of the crystal packing was analyzed through cooperativity of intermolecular interactions. Homo and heterochiral dimeric motifs were stabilized by intermolecular N−H⋅⋅⋅O, C−H⋅⋅⋅O, C−H⋅⋅⋅π interactions and parallel interactions at large offsets (PILO), thus forming alternating double layers. The greatest contribution to the total stabilization came from a motif of opposite enantiomers linked by N−H⋅⋅⋅O bonds (interaction energy=−13.72 kcal/mol), followed by a homochiral motif where the 4‐methoxybenzyl units allowed C−H⋅⋅⋅π, C−H⋅⋅⋅O interactions and PILO (interaction energy=−11.56 kcal/mol). The number of the contact fragments in the environment of the tetralin unit was larger, but the 4‐methoxybenzyl unit had greater contribution to the total stabilization. The statistical analysis of the data from the Cambridge Structural Database (CSD) showed that this is a general trend. The compound is a potential inhibitor of kinase enzymes and antigen protein‐coupled receptors. A correlation between the docking study and the results of the CSD analysis can be drawn. Due to a greater flexibility, the 4‐methoxybenzyl unit is more adaptable for interactions with the biological targets than the tetralin unit.
A Metal‐Free Electrode: From Biomass‐Derived Carbon to Hydrogen
Authors: Ding Yuxiao , Greiner Mark , Schlögl Robert , Heumann Saskia 
Published: May 2020

AbstractHydrogen is the emission‐free fuel of the future if produced from non‐fossil sources. Biomass gasification or electrolysis of water are possible clean routes. For a global application, the material solution for the electrodes must be sustainable, scalable, and relatively inexpensive compared to the current precious metal‐based electrodes. A key requirement to sustainable and green energy systems is that all harmful or rare resources utilized in the process must be part of a closed material cycle. Here, a carbon‐based electrode for hydrogen production is presented that can be part of a closed material cycle if produced from biomass. Continuous hydrogen production takes place at the cathode through catalytic water splitting during the oxygen evolution reaction (OER), while intentionally allowing the decomposition of the electrode into CO2 analogous to the process of natural biomass decomposition. This strategy of a sacrificial electrode could provide a scalable and low‐cost material solution for hydrogen production from renewable energy sources. The theoretical and technical feasibility of using carbon to produce hydrogen is demonstrated, and it is shown that chemical modification can further improve the performance characteristics towards the catalytic process. Combined with renewable energy derived electricity, this idea offers a real option for future energy systems.
Reproductive maturity and cone abundance vary with tree size and stand basal area for two widely distributed conifers
Authors: Andrus Robert A. , Harvey Brian J. , Hoffman Ashley , Veblen Thomas T. 
Published: May 2020

AbstractUnderstanding potential limitations to tree regeneration is essential as rates of tree mortality increase in response to direct (extreme drought) and indirect (bark beetle outbreaks, wildfire) effects of a warming climate. Seed availability is increasingly recognized as an important limitation for tree regeneration. High variability in seed cone production is a trait common among many northern temperate conifers, but few studies examine the determinants of individual tree cone production and how they vary with stand structure. In subalpine forests in the southern Rocky Mountains, USA, we monitored >1600 Picea engelmannii (Engelmann spruce) and Abies lasiocarpa (subalpine fir) trees for cone presence (an indicator of reproductive maturity) and a subset of those trees for cone abundance (an indicator of seed production) from 2016 to 2018. We constructed mixed models to test how individual tree cone presence and cone abundance were affected by tree size and age as well as forest attributes at the neighborhood‐ and stand‐scales. The probability of cone presence and cone abundance increased with tree size and age for A. lasiocarpa and P. engelmannii. The youngest ages of trees with cones present were more than 100 yr later for individuals in high basal area (BA) stands (>65 m2/ha) relative to low BA stands (<25 m2/ha). P. engelmannii produced many more cones than A. lasiocarpa at similar sizes, especially in young, low BA stands. Our findings reveal how differences in tree sizes and stand structures typically associated with time since last disturbance can affect seed production patterns for decades to well over a century. The consistent regional pattern of earlier and more abundant postfire establishment of P. engelmannnii vs. the delayed postfire establishment by A. lasiocarpa may be partially explained by species’ differences in cone abundance by stand structure. The increasing loss of large, dominant cone‐producing trees will significantly reduce seed production to support future tree regeneration and maintain forest cover. However, seed availability and resilience following disturbances may be less limiting than expected for species like P. engelmannii that have the capacity to produce more cones in open‐canopy forests, such as recently disturbed areas.