bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iron Gall Ink Revisited: In Situ Oxidation of Fe(II)–Tannin Complex for Fluidic‐Interface Engineering
Authors: Lee Hojae , Kim Won Il , Youn Wongu , Park Taegyun , Lee Sangmin , Kim Taek‐Soo , Mano João F. , Choi Insung S. 
Published: October 2018

AbstractThe ancient wisdom found in iron gall ink guides this work to a simple but advanced solution to the molecular engineering of fluidic interfaces. The Fe(II)–tannin coordination complex, a precursor of the iron gall ink, transforms into interface‐active Fe(III)–tannin species, by oxygen molecules, which form a self‐assembled layer at the fluidic interface spontaneously but still controllably. Kinetic studies show that the oxidation rate is directed by the counteranion of Fe(II) precursor salts, and FeCl2 is found to be more effective than FeSO4—an ingredient of iron gall ink—in the interfacial‐film fabrication. The optimized protocol leads to the formation of micrometer‐thick, free‐standing films at the air–water interface by continuously generating Fe(III)–tannic acid complexes in situ. The durable films formed are transferable, self‐healable, pliable, and postfunctionalizable, and are hardened further by transfer to the basic buffer. This O2‐instructed film formation can be applied to other fluidic interfaces that have high O2 level, demonstrated by emulsion stabilization and concurrent capsule formation at the oil–water interface with no aid of surfactants. The system, inspired by the iron gall ink, provides new vistas on interface engineering and related materials science.
Stretchable Suction Cup with Electroadhesion
Authors: Okuno Yuto , Shigemune Hiroki , Kuwajima Yu , Maeda Shingo 
Published: October 2018

AbstractSuction cups are commonly used as adhering and grasping devices. This study proposes a methodology to expand the applicability of suction cups. A suction cup is developed with a soft pad which consists of stretchable electrodes and insulating layers that bond to the bottom of the main body of the suction cup. When the stretchable electrodes generate an electrostatic attraction between the electrodes and the object, the pad deforms, filling the gaps between the pad and the object. Due to the soft pad, the amount of incoming air is significantly reduced compared to a normal suction cup. Experiments reveal the effect of these features. Applying a high voltage to the stretchable electrodes increases the holding success ratio of the suction cup in the normal direction for smooth and rough surfaces due to the stretchable electrodes. Measuring the negative pressure inside the suction cup confirms that the electrostatic force maintains the adhesion force on both smooth and rough surfaces. Thus, the electrostatic force and stretchability of the soft pad greatly increase the adhesion force of the suction cup. Furthermore, the electrostatic force prevents a slip of the suction cup, which improves the performance of the suction cup.
Highly Efficient Spintronic Terahertz Emitter Enabled by Metal–Dielectric Photonic Crystal
Authors: Feng Zheng , Yu Rui , Zhou Yu , Lu Hai , Tan Wei , Deng Hu , Liu Quancheng , Zhai Zhaohui , Zhu Liguo , Cai Jianwang , Miao Bingfeng , Ding Haifeng 
Published: October 2018

AbstractSpintronic terahertz (THz) emitter provides the advantages such as apparently broader spectrum, significantly lower cost, and more flexibility compared with the commercial THz emitters, and thus attracts great interest recently. In past few years, efforts have been made in optimizing the material composition and structure geometry, and the conversion efficiency has been improved close to that of ZnTe crystal. One of the drawbacks of the current designs is the rather limited laser absorption—more than 50% energy is wasted and the conversion efficiency is thus limited. Here, a novel device that fully utilizes the laser intensity and significantly improves the conversion efficiency is theoretically proposed and experimentally demonstrated. The device, which consists of a metal–dielectric photonic crystal structure, utilizes the interference between the multiple scattering waves to simultaneously suppress the reflection and transmission of the laser, and to reshape the laser field distributions. The experimentally detected laser absorption and THz generation show one‐to‐one correspondence with the theoretical calculations. The strongest THz pulse emission that presents a 1.7 times improvement compared to the currently designed spintronic emitter is achieved. This work opens a new pathway to improve the performance of spintronic THz emitter from the perspective of optics.
The Dawn of Single Material Organic Solar Cells
Authors: Roncali Jean , Grosu Ion 
Published: October 2018

AbstractSingle material organic solar cells (SMOSCs) are based on ambivalent materials containing electron donor (D) and acceptor (A) units capable to ensure the basic functions of light absorption, exciton dissociation, and charge transport. Compared to bicomponent bulk heterojunctions, SMOSCs present several major advantages such as considerable simplification of cell fabrication and a strong stabilization of the morphology of the D/A interface, and thus of the cell lifetime. In addition to these technical issues, SMOSCs pose fundamental questions regarding the possible formation, and dissociation of excitons on the same molecular D–A architecture. SMOSCs are developed with various approaches, namely “double‐cable” polymers, block copolymers, oligomers, and molecules that differ by the donor platform: polymer or molecule, the nature of A, the D–A connection, and the intra‐ and intermolecular interactions of D and A. Although for several years the maximum efficiency of SMOSCs has remained limited to 1.0–1.5%, impressive progress has been recently accomplished leading to SMOSCs with 4.0–5.0% efficiency. Here, recent advances in the synthesis of D–A materials for SMOSCs are presented in the broader context of the chemistry of organic photovoltaic materials in order to discuss possible directions for future research.
Biodegradable 2D Fe–Al Hydroxide for Nanocatalytic Tumor‐Dynamic Therapy with Tumor Specificity
Authors: Cao Zhenbang , Zhang Liang , Liang Kang , Cheong Soshan , Boyer Cyrille , Gooding J. Justin , Chen Yu , Gu Zi 
Published: October 2018

AbstractTherapeutic nanocatalysis has emerged as an intriguing strategy for efficient cancer‐specific therapy, but the traditional inorganic nanocatalysts suffer from low catalytic efficiency and difficulty in biodegradation, hindering their further clinical translation. Herein, a tumor microenvironment‐triggered, biodegradable and biocompatible nanocatalyst employing 2D hydroxide nanosheet is presented, and is shown to have high catalytic capacity to efficiently produce abundant hydroxyl radicals under the tumor microenvironment and consequently kill tumor cells selectively. A polyethylene glycol (PEG)‐conjugated Fe2+‐containing hydroxide nanosheet is successfully constructed via a facile but efficient bottom‐up approach that concurrently realizes nanosheet synthesis and PEGylation. Importantly, the nanosheets are featured with high catalytic activity to disproportionate H2O2 in tumors, and consequently generate abundant hydroxyl radicals at a high reaction rate under tumorous acidic condition; the highly toxic hydroxyl radicals, as a result, cause the death of tumor cells in vitro and suppress the tumor growth in vivo without the use of any supplementary toxic agent, only with the biocompatible nanocatalysts. Meanwhile, the desirable biodegradation and biocompatibility of the hydroxide nanosheet render a high degree of safety to the organism. Therefore, this work provides the first paradigm of biodegradable 2D nanocatalytic platform with concurrently high catalytic‐therapeutic performance and biosafety for efficient tumor‐specific treatment.
Spektroskopischer Nachweis einer attraktiven Kation‐Kation‐ Wechselwirkung in OH‐funktionalisierten ionischen Flüssigkeiten: ein H‐Brücken‐gebundenes kettenförmiges Trimer
Authors: Niemann Thomas , Strate Anne , Ludwig Ralf , Zeng Helen J. , Menges Fabian S. , Johnson Mark A. 
Published: October 2018

AbstractWir untersuchen die Bildung von wasserstoffverbrückten Domänen zwischen den kationischen Bestandteilen der ionischen Flüssigkeit (IL) 1‐(3‐Hydroxypropyl)‐pyridinium‐tetrafluoroborat [HPPy][BF4] mithilfe der kryogenen Ionenschwingungs‐Prädissoziationsspektroskopie von kalten (≈35 K) ionischen Gasphasenclustern und quantenchemischen Berechnungen. Eine Analyse der OH‐Streckschwingungen zeigt ein kettenförmiges OH⋅⋅⋅OH⋅⋅⋅OH⋅⋅⋅BF4−‐Strukturmotiv, an dem die drei Kationen in einem quinären kationischen Cluster (HPPy+)3(BF4−)2 beteiligt sind. Rechnungen belegen, dass die Anziehung dieser kooperativen H‐Brücken die Coulomb‐Abstoßung kompensiert und zu stabilen Komplexen führt, die erfolgreich mit den Komplexen konkurrieren, bei denen die OH‐Gruppen überwiegend an Anionen gebunden sind. Unser experimenteller und theoretischer Ansatz liefert wichtige Einblicke in die kooperativen Effekte, die zur Bildung von wasserstoffverbrückten Domänen unter Einbeziehung der kationischen Bestandteile von ILs führen.
Remodeling of the Photosynthetic Chain Promotes Direct CO2 Conversion into Valuable Aromatic Compounds
Authors: Ni Jun , Liu Hong‐Yu , Tao Fei , Wu Yu‐Tong , Xu Ping 
Published: October 2018

AbstractDirecting CO2 conversion using photosynthetic microorganisms offers a promising route to couple CO2 sequestration with petrochemical replacement. However, the low‐flux shikimate pathway remains largely unexploited for the synthesis of valuable aromatics. In addition, it is unclear how an enhanced low‐flux pathway would influence the photosynthetic chain. We created a powerful metabolic sink by introducing the 2‐phenylethanol pathway and an artificial feedback‐inhibition‐resistant cassette to Synechococcus elongatus. More than 30 % of the fixed carbon was redirected to the shikimate pathway for aromatic synthesis, and carbon fixation and O2 evolution increased significantly. A “self‐remodeling” mechanism of the photosynthetic chain was discovered, which accelerates electron transport and reduces energy waste. This study represents a significant step toward the industrial viability of CO2 conversion into aromatic compounds and provides design guidance for improving photosynthetic efficiency.
Selektive Übertragung eines Stickstoffatoms im [CeON]+/CH4‐System durch hocheffizientes Intersystem Crossing
Authors: Zhou Shaodong , Sun Xiaoyan , Yue Lei , Guo Cheng , Schlangen Maria , Schwarz Helmut 
Published: October 2018

AbstractDie thermischen Reaktionen von [CeON]+ mit Methan wurden mithilfe von FT‐ICR‐Massenspektrometrie und quantenchemischen Rechnungen untersucht. Als einziger Reaktionspfad wurde die Übertragung eines Stickstoffatoms vom Cluster‐Ion auf Methan beobachtet. Laut Rechnungen handelt es sich bei dem gebildeten Neutralmolekül entweder um CH2NH2 oder um CH3NH. Außer durch die relativ schwache OCe+‐N‐Bindung wird diese Reaktion auch von einem hocheffizienten Intersystem Crossing angetrieben. Mechanistische Aspekte und die damit verbundenen elektronischen Ursachen werden diskutiert, und ein detaillierter Vergleich von [CeON]+, [CeO]+, [CeN]+, [CeO2]+ und atomarem Stickstoff in deren Reaktionen mit CH4 wird geliefert.
Enantioselective Synthesis of Chiral‐at‐Sulfur 1,2‐Benzothiazines by CpxRhIII‐Catalyzed C−H Functionalization of Sulfoximines
Authors: Sun Yang , Cramer Nicolai 
Published: October 2018

AbstractSulfoximines with stereogenic sulfur atoms are attractive structural motifs in drug discovery. A direct catalytic enantioselective method for the synthesis of sulfur‐chiral 1,2‐benzothiazines from readily accessible diaryl sulfoximines is presented. Rhodium(III) complexes equipped with chiral cyclopentadienyl ligands and paired with suitable carboxylic acid additives engage in an enantiodetermining C−H activation directed by the sulfoximine group. Subsequent trapping of the rhodacycle with a broad range of diazoketones gives access to S‐chiral 1,2‐benzothiazines with synthetically highly attractive substitution patterns in good yields and enantioselectivities.
Substrate‐Induced Self‐Assembly of Cooperative Catalysts
Authors: Solís Muñana Pablo , Ragazzon Giulio , Dupont Julien , Ren Chloe Z.‐J. , Prins Leonard J. , Chen Jack L.‐Y. 
Published: October 2018

AbstractDissipative self‐assembly processes in nature rely on chemical fuels that activate proteins for assembly through the formation of a noncovalent complex. The catalytic activity of the assemblies causes fuel degradation, resulting in the formation of an assembly in a high‐energy, out‐of‐equilibrium state. Herein, we apply this concept to a synthetic system and demonstrate that a substrate can induce the formation of vesicular assemblies, which act as cooperative catalysts for cleavage of the same substrate.
Defined High Molar Mass Poly(2‐Oxazoline)s
Authors: Monnery Bryn D. , Jerca Valentin V. , Sedlacek Ondrej , Verbraeken Bart , Cavill Rachel , Hoogenboom Richard 
Published: October 2018

AbstractPoly(2‐alkyl‐2‐oxazoline)s (PAOx) are regaining interest for biomedical applications. However, their full potential is hampered by the inability to synthesise uniform high‐molar mass PAOx. In this work, we proposed alternative intrinsic chain transfer mechanisms based on 2‐oxazoline and oxazolinium chain‐end tautomerisation and derived improved polymerization conditions to suppress chain transfer, allowing the synthesis of highly defined poly(2‐ethyl‐2‐oxazoline)s up to ca. 50 kDa (dispersity (Ð) <1.05) and defined polymers up to at least 300 kDa (Ð<1.2). The determination of the chain transfer constants for the polymerisations hinted towards the tautomerisation of the oxazolinium chain end as most plausible cause for chain transfer. Finally, the method was applied for the preparation of up to 60 kDa molar mass copolymers of 2‐ethyl‐2‐oxazoline and 2‐methoxycarbonylethyl‐2‐oxazoline.
Cherenkov Radiation‐Mediated In Situ Excitation of Discrete Luminescent Lanthanide Complexes
Authors: Cosby Alexia G. , Ahn Shin Hye , Boros Eszter 
Published: October 2018

AbstractLanthanide luminescence, while ideal for in vivo applications owing to sharp emission bands within the optical window, requires high‐intensity, short‐wavelength excitation of small organic “antenna” chromophores in the vicinity of the lanthanide complex to access excited f‐orbital states through intersystem crossing. Herein, we explored Cherenkov radiation of the radioisotopes 18F and 89Zr as an in situ source of antenna excitation. The effective inter‐ and intramolecular excitation of the terbium(III) complexes of a macrocylic polyaminocarboxylate ligand (hydration number (q)=0, quantum yield (φ)=47 %) as well as its analogue functionalized to append an intramolecular Cherenkov excitation source (q=0.07, φ=63 %) was achieved. Using conventional small‐animal fluorescence imaging equipment, we have determined a detection limit of 2.5 nmol of Tb(III) complex in presence of 10 μCi of 18F or 89Zr. Our system is the first demonstration of the optical imaging of discrete luminescent lanthanide complexes without external short‐wave excitation.
Combined Esterification and Short‐Path Distillation for High‐Purity Pentaerythritol Ester from Palm Kernel for Biolubricants
Authors: Abd Maurad Zulina , Yeong Shoot Kian , Idris Zainab , Ishak Siti Afida 
Published: October 2018

AbstractThe development of specialty esters using palm‐based materials through a solventless and autocatalytic method was investigated. The C8−C10 fatty‐acid esters of pentaerythritol are the bases for high‐performance lubricants. In the present study, an easy and efficient method was developed using an esterification process coupled with short‐path distillation to produce high‐purity pentaerythritol ester (PEE) for the more complete removal of acid value (AV) in the end products. The compositions of the distilled PEE have the highest 96% w/w % tetraester at an evaporator temperature of 200–225 °C and a vacuum pressure of 0.05 mbar to retain a low AV of less than 1 mg KOH g−1 and a low hydroxyl value. The rate of heating at 30 °C h−1 was found to be crucial in obtaining high‐purity tetraester. According to Organization for Economic Cooperation and Development (OECD) 301F, PEE is readily biodegradable and 100% biodegradability can be achieved in less than 9 days. PEE produced has shown lubricant properties and can be used as a base stock for biolubricant composition.
Genetic Inactivation of ZCCHC6 Suppresses Interleukin‐6 Expression and Reduces the Severity of Experimental Osteoarthritis in Mice
Authors: Ansari Mohammad Y. , Khan Nazir M. , Ahmad Nashrah , Green Jonathan , Novak Kimberly , Haqqi Tariq M. 
Published: October 2018

ObjectiveCytokine expression is tightly regulated posttranscriptionally, but high levels of interleukin‐6 (IL‐6) in patients with osteoarthritis (OA) indicate that regulatory mechanisms are disrupted in this disorder. The enzyme ZCCHC6 (zinc‐finger CCHC domain–containing protein 6; TUT‐7) has been implicated in posttranscriptional regulation of inflammatory cytokine expression, but its role in OA pathogenesis is unknown. The present study was undertaken to investigate whether ZCCHC6 directs the expression of IL‐6 and influences OA pathogenesis in vivo.MethodsHuman and mouse chondrocytes were stimulated with recombinant IL‐1β. Expression of ZCCHC6 in human chondrocytes was knocked down using small interfering RNAs. IL‐6 transcript stability was determined by actinomycin D chase, and 3′‐uridylation of microRNAs was determined by deep sequencing. Zcchc6−/− mice were produced by gene targeting. OA was surgically induced in the knee joints of mice, and disease severity was scored using a semiquantitative grading system.ResultsZCCHC6 was markedly up‐regulated in damaged cartilage from human OA patients and from wild‐type mice with surgically induced OA. Overexpression of ZCCHC6 induced the expression of IL‐6, and its knockdown reduced IL‐6 transcript stability and IL‐1β–induced IL‐6 expression in chondrocytes. Reintroduction of Zcchc6 in Zcchc6−/− mouse chondrocytes rescued the IL‐1β–induced IL‐6 expression. Knockdown of ZCCHC6 reduced the population of micro‐RNA 26b (miR‐26b) with 3′‐uridylation by 60%. Zcchc6−/− mice with surgically induced OA produced low levels of IL‐6 and exhibited reduced cartilage damage and synovitis in the joints.ConclusionThese findings indicate that ZCCHC6 enhances IL‐6 expression in chondrocytes through transcript stabilization and by uridylating miR‐26b, which abrogates repression of IL‐6. Inhibition of IL‐6 expression and significantly reduced OA severity in Zcchc6−/− mice identify ZCCHC6 as a novel therapeutic target to inhibit disease pathogenesis.
Divergent Dynamic Kinetic Resolution of a Racemic Mixture of Four Stereoisomers via N‐Heterocyclic Carbene Organocatalysis
Authors: Vasamsetty Laxmaiah , Kong Xiangwen , Meng Miao , Yang Shuang , Xu Weici , Reddy Pogula Sreekanth , Fang Xinqiang 
Published: October 2018

AbstractRacemic mixtures of four stereoisomers are easily formed via many fundamental organic transformations, but the direct utilities of these mixtures have been less studied and remain large challenges to date. In this work, we introduce a new method, i.e., divergent dynamic kinetic resolution, to achieve the separation of racemic mixtures of four stereoisomers. The hypothesis was proved by using a N‐heterocyclic carbene‐catalyzed benzoin reaction, which afforded two separable diastereomeric products bearing three consecutive stereocenters with good to excellent enantioselectivties. We believe that this resolution protocol will find applications in more transformations.
Mixed Event‐Triggered Mechanism Modeling and Controlling for Networked Control Systems with Time‐Varying Delays and Uncertainties
Authors: Liu Bin , Liu Yicai 
Published: October 2018

AbstractThis paper is concerned with modeling and controlling under the mixed event‐triggered mechanism (ETM) for networked control systems (NCSs) with time‐varying delays and uncertainties. Firstly, an event‐triggered threshold is set by using both state and state‐independent informations in the mixed ETM. Then the event‐triggered NCSs with network‐induced time‐varying delays which exist in both sensor‐to‐controller and controller‐to‐actuator channels are modeled as a general time‐delay system. Based on the piecewise differentiable characteristic of the time‐varying delay and by using the approach of free weighting matrix and reciprocally convex, a less conservative criterion to be globally uniformly ultimately bounded (GUUB) stability and a controller design method are derived. Furthermore, an algorithm is proposed to obtain the desired mixed ETM and state‐feedback controller which can render the network load and control performance to reach an expected level. Compared with the relative and absolute ETMs, the proposed mechanism can effectively improve the transmission efficiency during the whole working time. Finally, a numerical example is given to show the effectiveness of the proposed approach.
Understanding the Reaction Interface in Lithium‐Oxygen Batteries
Authors: Huang Jun , Peng Zhangquan 
Published: October 2018

AbstractThe presented review article recapitulates the current state of the art in understanding three fundamental issues relevant to the reaction interface in lithium‐oxygen batteries; i) charge transport across lithium peroxide, ii) morphological evolution and identification of reactive sites, and iii) mechanisms of the involved oxygen reactions. Except of the discharge reaction mechanism, there is still a lack of a complete mechanistic picture for these fundamental issues. However, we are standing at the brink of connecting the single dots to draw the overall image. Neglect of double layer effects and nonlinearities has led us to stray from the path towards correct understanding of the charge transport. The current status of reaction sites reminds us of the parable of the blind and the elephant. Multiple in‐situ, cross‐validated methods and multiple working hypotheses are essential for a comprehensive understanding. More efforts, especially on identifying the reaction intermediates, are required to portray a unifying mechanistic scheme for the charge reaction mechanism.