bluuebunny/crossref_metadata_2025_split huggingface dataset:
π‐Phase Tin and Germanium Monochalcogenide Semiconductors: An Emerging Materials System
Authors: Abutbul Ran Eitan , Segev Elad , Argaman Uri , Makov Guy , Golan Yuval 
Published: June 2018

AbstractCubic π‐phase monochalcogenides (MX, M = Sn, Ge; X = S, Se) are an emerging new class of materials that has recently been discovered. Here, their thermodynamic stability, progress in synthetic routes, properties, and prospective applications are reviewed. The thermodynamic stability is demonstrated through density functional theory total energy and phonon spectra calculations, which show that the π‐phase polytype is stable across the monochalcogenide family. To date, only π‐phase tin monochalcogenides have been observed experimentally while π‐phase Ge‐monochalcogenides are predicted to be stable but are yet to be experimentally realized. Various synthetic preparation protocols of π‐SnS and π‐SnSe are described, focusing on surfactant‐assisted nanoparticle synthesis and chemical deposition of thin films from aqueous‐bath compositions. These techniques provide materials with different surface energies, which are likely to play a major role in stabilizing the π‐phase in nanoscale materials. The properties of this newly discovered family of semiconducting materials are discussed in comparison with their conventional orthorhombic polymorphs. These could benefit a number of photovoltaic and optoelectronic applications since, apart from being cubic, they also possess characteristic advantages, such as moderately low toxicity and natural abundance.
A Shape‐Induced Orientation Phase within 3D Nanocrystal Solids
Authors: Burian Max , Karner Carina , Yarema Maksym , Heiss Wolfgang , Amenitsch Heinz , Dellago Christoph , Lechner Rainer T. 
Published: June 2018

AbstractWhen nanocrystals self assemble into ordered superstructures they form functional solids that may inherit the electronical properties of the single nanocrystals. To what extent these properties are enhanced depends on the positional and orientational order of the nanocrystals within the superstructure. Here, the formation of micrometer‐sized free‐standing supercrystals of faceted 20 nm Bi nanocrystals is investigated. The self‐assembly process, induced by nonsolvent into solvent diffusion, is probed in situ by synchrotron X‐ray scattering. The diffusion‐gradient is identified as the critical parameter for controlling the supercrystal‐structure as well as the alignment of the supercrystals with respect to the substrate. Monte Carlo simulations confirm the positional order of the nanocrystals within these superstructures and reveal a unique orientation phase: the nanocrystal shape, determined by the atomic Bi crystal structure, induces a total of 6 global orientations based on facet‐to‐facet alignment. This parallel alignment of facets is a prerequisite for optimized electronic and optical properties within designed nanocrystal solids.
Giant Flexomagnetoelectric Effect in Dilute Magnetic Monolayer
Authors: Shen Yu‐Hao , Song Yu‐Xi , Tong Wen‐Yi , Shen Xin‐Wei , Gong Shi‐jing , Duan Chun‐Gang 
Published: June 2018

AbstractSpintronics rooted in the spin degree of freedom is of both theoretical and technological importance. The development of some fantastic properties for electrically controlling this degree of freedom encourages enormous effort to the research on magnetic systems which possess sensitive magnetic response to the electric field. Here, a giant flexomagnetoelectric effect is predicted in a typical dilute magnetic monolayer Mn‐doped MoS2. Combining lattice bending and magnetic doping, it is shown that the magnetic response and magnetic anisotropy can be greatly amplified under the applied electric field. Further investigations reveal that such an effect stems from the orbit‐dependent response of the single magnetic dopant. Physically, the electric field‐induced orbital polarization causes the spatial distribution change of the Mn‐3d orbital wavefunction, which is sensitive to the change of the orbital hybridization with the bent lattice. Hence the corresponding 3d energy levels can be controlled to shift near Fermi level via external electric field. These findings open a new route toward functional 2D materials design for flexible devices.
SiO2‐Enhanced Structural Stability and Strong Adhesion with a New Binder of Konjac Glucomannan Enables Stable Cycling of Silicon Anodes for Lithium‐Ion Batteries
Authors: Guo Songtao , Li Heng , Li Yaqian , Han Yong , Chen Kebei , Xu Gengzhao , Zhu Yingjie , Hu Xianluo 
Published: June 2018

AbstractSilicon‐based anodes with high theoretical capacity have intriguing potential applications for next‐generation high‐energy lithium‐ion batteries, but suffer from huge volumetric change that causes pulverization of electrodes. Rational design and construction of effective electrode structures combined with versatile binders remain a significant challenge. Here, a unique natural binder of konjac glucomannan (KGM) is developed and an amorphous protective layer of SiO2 is fabricated on the surface of Si nanoparticles (Si@SiO2) to enhance the adhesion. Benefiting from a plethora of hydroxyl groups, the KGM binder with inherently high adhesion and superior mechanical properties provides abundant contact sites to active materials. Molecular mechanics simulations and experimental results demonstrate that the enhanced adhesion between KGM and Si@SiO2 can bond the particles tightly to form a robust electrode. In addition to bridging KGM molecules, the SiO2‐functionalized surface may serve as a buffer layer to alleviate the stresses of Si nanoparticles resulting from the volume change. The as‐fabricated KGM/Si@SiO2 electrode exhibits outstanding structural stability upon long‐term cycles. A highly reversible capacity of 1278 mAh g−1 can be achieved over 1000 cycles at a current density of 2 A g−1, and the capacity decay is as small as 0.056% per cycle.
Porous Trimetallic PtRhCu Cubic Nanoboxes for Ethanol Electrooxidation
Authors: Han Shu‐He , Liu Hui‐Min , Chen Pei , Jiang Jia‐Xing , Chen Yu 
Published: June 2018

AbstractDirect ethanol fuel cells (DEFCs) have great activity as a green energy conversion device. However, the weak activity of most anode electrocatalysts for the CC bond cleavage is an obstacle to the DEFCs development. Herein, a simple galvanic replacement reaction strategy to synthesize hollow and porous PtRhCu trimetallic nanoboxes (CNBs) with a tunable Pt/Rh atomic ratio is developed. For the ethanol oxidation reaction (EOR), PtRhCu CNBs show morphology and composition‐dependent electrocatalytic activity. The composition optimized Pt54Rh4Cu42 CNBs exhibit excellent specific and mass activity and stability for the EOR, which is attributed to its unique geometric structure and synergistic effects. The hollow porous structure can effectively enhance the atomic utilization and mass transfer. The introduction of Cu improves the antipoisoning capability for CO. The introduction of Rh elevates the self‐stability of PtRhCu CNBs. More importantly, further electrochemical results confirm that the introduction of Rh significantly promotes the cleavage of CC bonds, leading to the transformation of the main catalytic pathway for EOR from C2 to C1 pathway. The real concentration detection for C2 products (CH3COOH and CH3CHO) shows Pt54Rh4Cu42 CNBs have a nearly 11.5‐fold C1 pathway enhancement compared to Pt nanoparticles, showing an obvious selectivity enhancement for the C1 pathway.
Total Synthesis and Biological Evaluation of the Glycosylated Macrocyclic Antibiotic Mangrolide A
Authors: Hattori Hiromu , Roesslein Joel , Caspers Patrick , Zerbe Katja , Miyatake‐Ondozabal Hideki , Ritz Daniel , Rueedi Georg , Gademann Karl 
Published: June 2018

AbstractThe macrocyclic antibiotic mangrolide A has been described to exhibit potent activity against a number of clinically important Gram‐negative pathogens. Reported is the first enantioselective total synthesis of mangrolide A and derivatives. Salient features of this synthesis include a highly convergent macrocycle preparation, stereoselective synthesis of the disaccharide moiety, and two β‐selective glycosylations. The synthesis of mangrolide A and its analogues enabled the re‐examination of its activity against bacterial pathogens, and only minimal activity was observed.
Asymmetric Synthesis of Axially Chiral 2‐Aminobiaryls by Rhodium‐Catalyzed Benzannulation of 1‐Arylalkynes with 2‐(Cyanomethyl)phenylboronates
Authors: Xue Fei , Hayashi Tamio 
Published: June 2018

AbstractAsymmetric benzannulation of 1‐arylalkynes, where the aryl group is an ortho‐substituted aromatic group, with 2‐(cyanomethyl)phenylboronate was catalyzed by a rhodium complex coordinated with a chiral diene ligand to give high yields of axially chiral 2‐aminobiaryls with greater than 90 % ee.
A Peri‐tetracene Diradicaloid: Synthesis and Properties
Authors: Ni Yong , Gopalakrishna Tullimilli Y. , Phan Hoa , Herng Tun Seng , Wu Shaofei , Han Yi , Ding Jun , Wu Jishan 
Published: June 2018

AbstractPeri‐acenes are good model compounds for zigzag graphene nanoribbons, but their synthesis is extremely challenging owing to their intrinsic open‐shell diradical character. Now, the successful synthesis and isolation of a stable peri‐tetracene derivative PT‐2ClPh is reported; four 2,6‐dichlorophenyl groups are attached onto the most reactive sites along the zigzag edges. The structure was confirmed by X‐ray crystallographic analysis and its electronic properties were systematically investigated by both experiments and theoretical calculations. It exhibits an open‐shell singlet ground state with a moderate diradical character (y0=51.5 % by calculation) and a small singlet–triplet gap (ΔES‐T=−2.5 kcal mol−1 by SQUID measurement). It displays global aromatic character, which is different from the smaller‐size bisanthene analogue BA‐CF3.
Multistage Microfluidic Platform for the Continuous Synthesis of III–V Core/Shell Quantum Dots
Authors: Baek Jinyoung , Shen Yi , Lignos Ioannis , Bawendi Moungi G. , Jensen Klavs F. 
Published: June 2018

AbstractWe present a fully continuous chip microreactor‐based multistage platform for the synthesis of quantum dots with heterostructures. The use of custom‐designed chip reactors enables precise control of heating profiles and flow distribution across the microfluidic channels while conducting multistep reactions. The platform can be easily reconfigured by reconnecting the differently designed chip reactors allowing for screening of various reaction parameters during the synthesis of nanocrystals. III–V core/shell quantum dots are chosen as model reaction systems, including InP/ZnS, InP/ZnSe, InP/CdS and InAs/InP, which are prepared in flow using a maximum of six chip reactors in series.
Bayesian variable selection logistic regression with paired proteomic measurements
Authors: Kakourou Alexia , Mertens Bart 
Published: June 2018

AbstractWe explore the problem of variable selection in a case‐control setting with mass spectrometry proteomic data consisting of paired measurements. Each pair corresponds to a distinct isotope cluster and each component within pair represents a summary of isotopic expression based on either the intensity or the shape of the cluster. Our objective is to identify a collection of isotope clusters associated with the disease outcome and at the same time assess the predictive added‐value of shape beyond intensity while maintaining predictive performance. We propose a Bayesian model that exploits the paired structure of our data and utilizes prior information on the relative predictive power of each source by introducing multiple layers of selection. This allows us to make simultaneous inference on which are the most informative pairs and for which—and to what extent—shape has a complementary value in separating the two groups. We evaluate the Bayesian model on pancreatic cancer data. Results from the fitted model show that most predictive potential is achieved with a subset of just six (out of 1289) pairs while the contribution of the intensity components is much higher than the shape components. To demonstrate how the method behaves under a controlled setting we consider a simulation study. Results from this study indicate that the proposed approach can successfully select the truly predictive pairs and accurately estimate the effects of both components although, in some cases, the model tends to overestimate the inclusion probability of the second component.
A novel cytochrome P450 mono‐oxygenase from Streptomyces platensis resembles activities of human drug metabolizing P450s
Authors: Worsch Anne , Eggimann Fabian Kurt , Girhard Marco , von Bühler Clemens J. , Tieves Florian , Czaja Rico , Vogel Andreas , Grumaz Christian , Sohn Kai , Lütz Stephan , Kittelmann Matthias , Urlacher Vlada B. 
Published: June 2018

AbstractCytochrome P450 mono‐oxygenases (P450) are versatile enzymes which play essential roles in C‐source assimilation, secondary metabolism, and in degradations of endo‐ and exogenous xenobiotics. In humans, several P450 isoforms constitute the largest part of phase I metabolizing enzymes and catalyze oxidation reactions which convert lipophilic xenobiotics, including drugs, to more water soluble species. Recombinant human P450s and microorganisms are applied in the pharmaceutical industry for the synthesis of drug metabolites for pharmacokinetics and toxicity studies. Compared to the membrane‐bound eukaryotic P450s, prokaryotic ones exhibit some advantageous features, such as high stability and generally easier heterologous expression. Here, we describe a novel P450 from Streptomyces platensis DSM 40041 classified as CYP107L that efficiently converts several commercial drugs of various size and properties. This P450 was identified by screening of actinobacterial strains for amodiaquine and ritonavir metabolizing activities, followed by genome sequencing and expression of the annotated S. platensis P450s in Escherichia coli. Performance of CYP107L in biotransformations of amodiaquine, ritonavir, amitriptyline, and thioridazine resembles activities of the main human metabolizing P450s, namely CYPs 3A4, 2C8, 2C19, and 2D6. For application in the pharmaceutical industry, an E. coli whole‐cell biocatalyst expressing CYP107L was developed and evaluated for preparative amodiaquine metabolite production.
Co‐immobilized Whole Cells with ω‐Transaminase and Ketoreductase Activities for Continuous‐Flow Cascade Reactions
Authors: Nagy‐Győr László , Abaházi Emese , Bódai Viktória , Sátorhelyi Péter , Erdélyi Balázs , Balogh‐Weiser Diána , Paizs Csaba , Hornyánszky Gábor , Poppe László 
Published: June 2018

AbstractAn improved sol–gel process involving the use of hollow silica microspheres as a supporting additive was applied for the co‐immobilization of whole cells of Escherichia coli with Chromobacterium violaceum ω‐transaminase activity and Lodderomyces elongisporus with ketoreductase activity. The co‐immobilized cells with two different biocatalytic activities could perform a cascade of reactions to convert racemic 4‐phenylbutan‐2‐amine or heptan‐2‐amine into a nearly equimolar mixture of the corresponding enantiomerically pure R amine and S alcohol even in continuous‐flow mode. The novel co‐immobilized whole‐cell system proved to be an easy‐to‐store and durable biocatalyst.
High‐Throughput Measurement of Small‐Molecule Enantiopurity by Using Flow Cytometry
Authors: Tan Zhesen , Heemstra Jennifer M. 
Published: June 2018

AbstractFluorescence‐activated cell sorting (FACS) offers a powerful approach to high‐throughput library screening in directed evolution experiments. However, FACS is rarely used in the evolution of stereoselective enzymes, due to the difficulty of designing fluorescence‐based assays for measuring enantiopurity. Here, we describe a new FACS‐based enantiopurity analysis approach that overcomes these limitations by using enantiomeric DNA biosensors labeled with orthogonal fluorophores. By co‐encapsulating the biosensors with a mixture of target enantiomers in microfluidic droplets, we could demonstrate the use of FACS to differentiate between droplets having various levels of target enantiopurity. We envision the utility of this method for high‐throughput screening of enantiopurity in the directed evolution of stereoselective enzymes, thereby facilitating the discovery of new asymmetric biocatalysts for the synthesis of pharmaceuticals and other high‐value chemicals.
Nanoparticle@Metal‐Organic Frameworks as a Template for Hierarchical Porous Carbon Sponges
Authors: Salazar‐Beltrán Daniel , Cabello Carlos Palomino , Guzmán‐Mar Jorge Luis , Hinojosa‐Reyes Laura , Palomino Gemma Turnes , Maya Fernando 
Published: June 2018

AbstractThe preparation of hierarchical porous carbon sponges (HCS) from metal oxide nanoparticle@metal‐organic frameworks is reported. ZnO nanoparticles are partially converted to zeolitic imidazolate framework‐8 (ZIF‐8) crystals in presence of n‐butylamine to obtain ZnO@ZIF‐8 porous hybrids. After direct carbonization, followed by ZnO acidic etching, ZnO@ZIF‐8 crystals were converted to submicrometric HCS. Due to the high surface area and accessible porosity, combining micro‐ and mesoporosity of HCS, their application for the extraction of water pollutants was studied by preparing HCS/polymer membranes, and showed a high efficiency for the fast (650 L m−2 h−1) removal of plastic degradation by‐products (DBP, dibutyl phthalate. DEHP, bis(2‐n‐ethylhexyl)phthalate). DBP and DEHP breakthroughs were lower than 3 % after the filtration of 100 mL of water containing simultaneously both phthalates at a high concentration level (300 μg L−1, each). HCS/polymer membranes were reusable up to 5 times, maintaining their extraction capacity, with relative errors of 6 % for DBP, and <1 % for DEHP.
Modular Preparation of Graphene‐Based Functional Architectures through Two‐Step Organic Reactions: Towards High‐Performance Energy Storage
Authors: Zhang Xiaoyan , Hou Lili , Richard Fanny , Samorì Paolo 
Published: June 2018

AbstractGraphene‐based materials have recently attracted much attention due to their extraordinary physical and chemical properties, which make them attractive candidates for many technological applications in sensing, optoelectronics, catalysis, and energy storage. Their chemical functionalization is key to tuning their properties. Herein, a novel two‐step synthetic approach, which enables a high degree of covalent functionalization of graphene oxide (GO) is devised, thereby making the facile attachment of various robust functional molecules possible. Such a process relies initially on the grafting of an ethylenediamine linker followed by a second step consisting of the condensation reaction between aldehyde and amine groups to form imine bonds. As test beds, two kinds of graphene‐based functional systems, namely, porphyrin‐modified GO and ferrocene‐modified GO, are prepared. Such hybrid systems are characterized by various spectroscopic and microscopic techniques. The degree of functionalization is quantified as the attachment of one porphyrin or ferrocene unit to every 34 or 77 carbon atoms of the GO scaffold, respectively, which is much higher than that of values obtained upon using various established chemical approaches to functionalize GO, such as condensation, cycloaddition, or coupling reactions. For the first time, the reduced form of ferrocene‐modified GO was employed as an electrode material in supercapacitors, showing a specific capacitance of 127 F g−1 at a current density of 1 A g−1, with capacitance retention of about 93 % after 5000 cycles at the same current density; this demonstrates great potential for application in high‐performance energy‐storage devices.
Influence of Crosshead Speed and Particle Size on the Bursting Behavior of Agar Beads
Authors: Höft Steffi , Waluga Thomas , Scholl Stephan 
Published: June 2018

AbstractDie mechanische Charakterisierung von Enzym‐ und Zellimmobilisaten stellt eine wesentliche Voraussetzung für deren Auswahl und Design zum Einsatz in Bioreaktoren dar. Vor diesem Hintergrund wurde das Bruchverhalten von Agarperlen unterschiedlicher Agarkonzentrationen mithilfe eines Texture Analyzers untersucht. Hierbei konnten ein Einfluss des umgebenden Mediums ausgeschlossen und signifikante Abhängigkeiten des Bruchverhaltens von Beanspruchungsgeschwindigkeit und Perlengröße festgestellt werden.
Chinin, ein legendäres Alkaloid
Authors: Rudo Anna , Zeller Klaus‐Peter , Siehl Hans‐Ullrich , Berger Stefan , Sicker Dieter 
Published: June 2018

ZusammenfassungChinin, schon 1820 als eines der ersten Alkaloide rein isoliert, ist eines der wertvollsten Medikamente, mit dem seit Jahrhunderten und noch heute Malaria behandelt wird. Wie seine Quelle, der Chinarindenbaum, ist es legendenumwoben. Wir belegen mit Zitaten aus Reviews sowohl diesen spektakulären Hintergrund als auch die Anstrengungen zur Isolierung, Strukturaufklärung und Totalsynthese, die die Organische Chemie vorangebracht haben. Wenn wir Tonic Water oder Gin Tonic trinken, nehmen wir selbst Chinin als Bitterstoff auf. Wir zeigen seine eindrucksvolle blaue Fluoreszenz unter UV‐Bestrahlung und diskutieren weitere Anwendungen. Im Zentrum des Artikels steht die spektroskopische Analyse des Alkaloids für das wir eine Laborvorschrift zum Isolieren aus Chinarinde angeben.
Verifiable Chebyshev maps‐based chaotic encryption schemes with outsourcing computations in the cloud/fog scenarios
Authors: Li Jing , Wang Licheng , Wang Lihua , Wang Xianmin , Huang Zhengan , Li Jin 
Published: June 2018

SummaryBased on cloud servers' powerful storage and computing resources, users can store mass encrypted data in the cloud and outsource complex encryption computations to the cloud servers. Since cloud servers cannot be completely trusted, then data privacy and integrity are concerned about hot issues. We focus on the following problems in outsourced encryptions: how to protect the data privacy and how to check the integrity of data and the correctness of cloud server's outsourcing computations. In this paper, we at first propose a verifiable chaotic encryption based on Chebyshev polynomials. The scheme supports verifiable function for data integrity. To further improve the efficiency of the scheme, a corresponding outsourced encryption scheme is constructed, where the heavy overhead evaluations of Chebyshev polynomials are transferred from the user side to the cloud server. The outsourced encryption also provides the checkability for data integrity and correctness of cloud computations. The scheme is suitable for mobile users with limited computing resources. Moreover, the newly proposed scheme no longer depends upon the simple heuristic analysis. It achieves the indistinguishability under chosen‐ciphertext attacks (IND‐CCA) in the standard model based on the Chebyshev‐based Decisional Diffie‐Hellman (CDDH) assumption. Thus, we answer a long‐term open problem for building a chaotic encryption scheme with provable security in the sense of the IND‐CCA.