bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selen und Selenocystein in der Proteinchemie
Authors: Mousa Reem , Notis Dardashti Rebecca , Metanis Norman 
Published: August 2017

AbstractSelenocystein, das selenhaltige Analogon des Cysteins, ist die 21. proteinogene Aminosäure. Seit ihrer Entdeckung vor beinahe fünfzig Jahren ist ihre Rolle biologischen Systemen intensiv untersucht worden, in nichtnatürlichen noch häufiger als in natürlichen. Die Chemie des Selenocysteins hat aufgrund der hohen Reaktivität der Verbindung und des daraus resultierenden Potentials für diverse Anwendungen, z. B. in der chemischen Modifizierung, der chemische Protein(semi)synthese oder der Proteinfaltung, viel Aufmerksamkeit auf dem Gebiet der chemischen Biologie auf sich gezogen. In diesem Kurzaufsatz richten wir den Fokus auf die Chemie des Selens und des Selenocysteins sowie deren Nutzen in der Proteinchemie.
Das Aufrollen von Oligophenylenen zu Nanographenen durch einen HF‐Reißverschluss
Authors: Steiner Ann‐Kristin , Amsharov Konstantin Y. 
Published: August 2017

AbstractDie intramolekulare Aryl‐Aryl‐Kupplung ist die Schlüsselumwandlung in der rationalen Synthese von Nanographenen und Nanobändern. In dieser Hinsicht erwies sich die C‐F‐Bindungsaktivierung als eine vielseitige Alternative, die die Synthese mehrerer einzigartiger Kohlenstoff‐basierter Nanostrukturen ermöglicht. Hier beschreiben wir eine beispiellos anspruchsvolle Transformation, die zeigt, dass die C‐F‐Bindungsaktivierung durch Aluminiumoxid eine hochwirksame Domino‐C‐C‐Bindungsbildung ermöglicht. Trotz der flexiblen Struktur der Oligophenylen‐basierten Vorstufen gelingt ein effizienter regioselektiver Aufbau der Zielstrukturen. Die Fluorpositionen in der Vorstufe geben eindeutig das “Reißverschluss‐Programm” vor, welches zu einem Aufrollen von linearen Oligophenylenketten um einen Phenylrest führt und die gewünschten Nanographene ergibt. Das hoch effiziente Verfahren ist attraktiv für die Synthese nichtsubstituierter Nanographenen, die durch alternative Methoden in reiner Form schwer zugänglich sind.
Because the Light is Better Here: Correlation‐Time Analysis by NMR Spectroscopy
Authors: Smith Albert A. , Ernst Matthias , Meier Beat H. 
Published: August 2017

AbstractRelaxation data in NMR spectra are often used for dynamics analysis, by modeling motion in the sample with a correlation function consisting of one or more decaying exponential terms, each described by an order parameter, and a correlation time. This method has its origins in the Lipari–Szabo model‐free approach, which originally considered overall tumbling plus one internal motion and was later expanded to several internal motions. Considering several of these cases in the solid state it is found that if the real motion is more complex than the assumed model, model fitting is biased towards correlation times where the relaxation data are most sensitive. This leads to unexpected distortions in the resulting dynamics description. Therefore dynamics detectors should be used, which characterize different ranges of correlation times and can help in the analysis of protein motion without assuming a specific model of the correlation function.
Rocking‐Chair Ammonium‐Ion Battery: A Highly Reversible Aqueous Energy Storage System
Authors: Wu Xianyong , Qi Yitong , Hong Jessica J. , Li Zhifei , Hernandez Alexandre S. , Ji Xiulei 
Published: August 2017

AbstractAqueous rechargeable batteries are promising solutions for large‐scale energy storage. Such batteries have the merit of low cost, innate safety, and environmental friendliness. To date, most known aqueous ion batteries employ metal cation charge carriers. Here, we report the first “rocking‐chair” NH4‐ion battery of the full‐cell configuration by employing an ammonium Prussian white analogue, (NH4)1.47Ni[Fe(CN)6]0.88, as the cathode, an organic solid, 3,4,9,10‐perylenetetracarboxylic diimide (PTCDI), as the anode, and 1.0 m aqueous (NH4)2SO4 as the electrolyte. This novel aqueous ammonium‐ion battery demonstrates encouraging electrochemical performance: an average operation voltage of ca. 1.0 V, an attractive energy density of ca. 43 Wh kg−1 based on both electrodes’ active mass, and excellent cycle life over 1000 cycles with 67 % capacity retention. Importantly, the topochemistry results of NH4+ in these electrodes point to a new paradigm of NH4+‐based energy storage.
Polysulfid‐Koordinationscluster der Lanthanoide
Authors: Ma Ying‐Zhao , Bestgen Sebastian , Gamer Michael T. , Konchenko Sergey N. , Roesky Peter W. 
Published: August 2017

AbstractDie Reaktion von [(DippForm)2Ln(thf)2] mit einem Überschuss an elementaren Schwefel führt in Toluol zur Bildung der dreikernigen Polysulfid‐Koordinationscluster [(DippForm)3Ln3S12] (Ln=Sm, Yb; DippForm=N,N′‐bis(2,6‐diisopropylphenyl)‐formamidinat). Dies sind die ersten f‐Element‐Koordinationscluster (LnnSx) mit einer größeren Polysulfideinheit (n und x>2). Die Bildung dieser Spezies kann über die reduktive Spaltung von Cyclooctaschwefel (S8) mittels zweiwertiger Lanthanoide erklärt werden.
Photoaktivierung von Cerdioxid: die Rolle von Defekten
Authors: Yang Chengwu , Yu Xiaojuan , Pleßow Philipp N. , Heißler Stefan , Weidler Peter G. , Nefedov Alexei , Studt Felix , Wang Yuemin , Wöll Christof 
Published: August 2017

AbstractDie Photoreaktivität von Cerdioxid, einem photochemisch inaktiven Oxid mit großer Bandlücke, lässt sich durch die Erzeugung von O‐Leerstellen deutlich steigern. Zur Klärung des Mechanismus wurde die UV‐induzierte Zersetzung von N2O an Einkristall‐Modellsystemen dieses Materials mithilfe von IRRAS untersucht. In Verbindung mit theoretischen Erkenntnissen bestätigen die IRRAS‐Daten, dass eine Reduzierung der Cerdioxid‐(110)‐Oberfläche zu einer hohen Photoreaktivität führt. An der (111)‐Oberfläche sind dagegen keine solchen Effekte zu beobachten. Der Tieftemperatur‐Photoabbau von N2O erfolgt hauptsächlich an O‐Leerstellen an der (110)‐Oberfläche. An diesen Defekten verkleinern die elektronenreichen Cerkationen die große Bandlücke (ca. 6 eV) lokal erheblich. Die Quanteneffizienz der stark reduzierten (110)‐Oberflächen von Cerdioxid beim Photoabbau von N2O ist erstaunlich hoch. Der Wert von 0.03 % ist vergleichbar mit dem Wirkungsgrad, der für die Photooxidation von CO an Rutil‐Titandioxid‐(110) beobachtet wurde.
H2S‐Activable MOF Nanoparticle Photosensitizer for Effective Photodynamic Therapy against Cancer with Controllable Singlet‐Oxygen Release
Authors: Ma Yu , Li Xiangyuan , Li Aijie , Yang Peng , Zhang Caiyun , Tang Bo 
Published: August 2017

AbstractPhotodynamic therapy (PDT) has emerged as an important minimally invasive tumor treatment technology. The search for an effective photosensitizer to realize selective cancer treatment has become one of the major foci in recent developments of PDT technology. Controllable singlet‐oxygen release based on specific cancer‐associated events, as another major layer of selectivity mode, has attracted great attention in recent years. Here, for the first time, we demonstrated that a novel mixed‐metal metal–organic framework nanoparticle (MOF NP) photosensitizer can be activated by a hydrogen sulfide (H2S) signaling molecule in a specific tumor microenvironment for PDT against cancer with controllable singlet‐oxygen release in living cells. The effective removal of tumors in vivo further confirmed the satisfactory treatment effect of the MOF NP photosensitizer.
Regioselektive para‐Carboxylierung von Catecholen mit einer Prenylflavin‐abhängigen Decarboxylase
Authors: Payer Stefan E. , Marshall Stephen A. , Bärland Natalie , Sheng Xiang , Reiter Tamara , Dordic Andela , Steinkellner Georg , Wuensch Christiane , Kaltwasser Susann , Fisher Karl , Rigby Stephen E. J. , Macheroux Peter , Vonck Janet , Gruber Karl , Faber Kurt , Himo Fahmi , Leys David , Pavkov‐Keller Tea , Glueck Silvia M. 
Published: August 2017

AbstractDie Verwendung von CO2 als Kohlenstoffquelle in der Synthese organischer Verbindungen entspricht den aktuellen Bemühungen für eine nachhaltigere Produktion von Chemikalien. Wir beschreiben hier die enzymkatalysierte para‐Carboxylierung von Catecholen durch eine 3,4‐Dihydroxybenzoesäure‐Decarboxylase (AroY) aus der UbiD‐Enzymfamilie. Die Kristallstrukturen und experimentelle Daten zeigen, dass dieses Enzym ein erst kürzlich entdecktes prenyliertes Flavin als Cofaktor benötigt (prFMN) und oxidative Prozesse zur Bildung der katalytisch aktiven prFMNiminium‐Spezies führen. Diese Studie beschreibt die In‐vitro‐Rekonstitution und Aktivierung dieser prFMN‐abhängigen Enzyme, welche die direkte Carboxylierung von aromatischen Catecholen unter milden Bedingungen katalysieren. Ein Reaktionsmechanismus für den reversiblen Carboxylierungsprozess über ein Intermediat mit einfach kovalent gebundener Chinoidform des Substrats wird vorgeschlagen, der sich von dem 1,3‐Cycloadditionsmechanismus in verwandten Enzymen unterscheidet.
Stereoselective Synthesis of Z Fluoroalkenes through Copper‐Catalyzed Hydrodefluorination of gem‐Difluoroalkenes with Water
Authors: Hu Jiefeng , Han Xiaowei , Yuan Yu , Shi Zhuangzhi 
Published: August 2017

AbstractA copper catalytic system was established for the stereoselective hydrodefluorination of gem‐difluoroalkenes through C−F activation to synthesize various Z fluoroalkenes. H2O is used as the hydrogen source for the fluorine acceptor moiety. This mild catalytic system shows good‐functional group compatibility, accepting a range of carbonyls as precursors to the gem‐difluoroalkenes, including aliphatic, aromatic, and α,β‐unsaturated aldehydes and even ketones. It serves as a powerful synthetic method for the late‐stage modification of complex compounds.
Wellenlängenselektive freie radikalische Photopolymerisation zur einfachen Herstellung von Sternpolymeren
Authors: Eibel Anna , Fast David E. , Sattelkow Jürgen , Zalibera Michal , Wang Jieping , Huber Alex , Müller Georgina , Neshchadin Dmytro , Dietliker Kurt , Plank Harald , Grützmacher Hansjörg , Gescheidt Georg 
Published: August 2017

AbstractSternpolymere finden zunehmende Bedeutung auf den schnell wachsenden Gebieten der Nanotechnologie und der Lebenswissenschaften, unter anderem in den Bereichen diagnostische Bildgebung, Gewebezüchtung und gezielte Wirkstoff‐Freisetzung. Hier wird über eine effiziente Methode zur Synthese von wellenlängenselektiven multifunktionellen Photoinitiatoren (PIs) berichtet, die aus einer Bisacylphosphanoxid(BAPO)‐ und einer α‐Hydroxyketon‐Einheit bestehen. Diese photoaktiven Gruppen werden bei drei unterschiedlichen Wellenlängen selektiv angeregt und aktiviert. Dies ermöglicht die Herstellung von ABC‐Miktoarm‐Sternpolymeren mithilfe einer einfachen, hochselektiven und robusten radikalischen Polymerisation. Die Photochemie dieser neuartigen Initiatoren und die Möglichkeiten ihrer Anwendbarkeit wurden mit einer Reihe spektroskopischer Methoden detailliert untersucht.
Preorganization and Cooperation for Highly Efficient and Reversible Capture of Low‐Concentration CO2 by Ionic Liquids
Authors: Huang Yanjie , Cui Guokai , Zhao Yuling , Wang Huiyong , Li Zhiyong , Dai Sheng , Wang Jianji 
Published: August 2017

AbstractA novel strategy based on the concept of preorganization and cooperation has been designed for a superior capacity to capture low‐concentration CO2 by imide‐based ionic liquids. By using this strategy, for the first time, an extremely high gravimetric CO2 capacity of up to 22 wt % (1.65 mol mol−1) and excellent reversibility (16 cycles) have been achieved from 10 vol. % of CO2 in N2 when using an ionic liquid having a preorganized anion. Through a combination of quantum‐chemical calculations and spectroscopic investigations, it is suggested that cooperative interactions between CO2 and multiple active sites in the preorganized anion are the driving force for the superior CO2 capacity and excellent reversibility.
Ultrafast Charge Transfer and Upconversion in Zinc β‐Tetraaminophthalocyanine‐Functionalized PbS Nanostructures Probed by Transient Absorption Spectroscopy
Authors: Lauth Jannika , Grimaldi Gianluca , Kinge Sachin , Houtepen Arjan J. , Siebbeles Laurens D. A. , Scheele Marcus 
Published: August 2017

AbstractWe functionalize PbS nanocrystals with the organic semiconductor Zn β‐tetraaminophthalocyanine to design a nanostructured solid‐state material with frequent organic–inorganic interfaces. By transient absorption and fluorescence spectroscopy, we investigate the optoelectronic response of this hybrid material under near‐infrared excitation to find efficient charge transfer from the nanocrystals to the molecules. We demonstrate that the material undergoes cooperative sensitization of two nanocrystals followed by photon upconversion and singlet emission of the organic semiconductor. The upconversion efficiency resembles that of comparable systems in solution, which we attribute to the large amount of interfaces present in this solid‐state film. We anticipate that this synthetic strategy has great prospects for increasing the open‐circuit voltage in PbS nanocrystal‐based solar cells.
Polysulfide Coordination Clusters of the Lanthanides
Authors: Ma Ying‐Zhao , Bestgen Sebastian , Gamer Michael T. , Konchenko Sergey N. , Roesky Peter W. 
Published: August 2017

AbstractThe reaction of [(DippForm)2Ln(thf)2] with an excess of elemental sulfur in toluene resulted in the formation of the trinuclear polysulfide coordination clusters [(DippForm)3Ln3S12] (Ln=Sm, Yb; DippForm=N,N′‐bis(2,6‐diisopropylphenyl)formamidinate). These are the first f element coordination clusters (LnnSx) with a larger polysulfide unit (n and x>2). The formation of the coordination clusters can be rationalized by the reductive cleavage of S8 with divalent lanthanides.
Constructing a Strongly Absorbing Low‐Bandgap Polymer Acceptor for High‐Performance All‐Polymer Solar Cells
Authors: Zhang Zhi‐Guo , Yang Yankang , Yao Jia , Xue Lingwei , Chen Shanshan , Li Xiaojun , Morrison William , Yang Changduk , Li Yongfang 
Published: August 2017

AbstractAll‐polymer solar cells (all‐PSCs) offer unique morphology stability for the application as flexible devices, but the lack of high‐performance polymer acceptors limits their power conversion efficiency (PCE) to a value lower than those of the PSCs based on fullerene derivative or organic small molecule acceptors. We herein demonstrate a strategy to synthesize a high‐performance polymer acceptor PZ1 by embedding an acceptor–donor–acceptor building block into the polymer main chain. PZ1 possesses broad absorption with a low band gap of 1.55 eV and high absorption coefficient (1.3×105 cm−1). The all‐PSCs with the wide‐band‐gap polymer PBDB‐T as donor and PZ1 as acceptor showed a record‐high PCE of 9.19 % for the all‐PSCs. The success of our polymerization strategy can provide a new way to develop efficient polymer acceptors for all‐PSCs.
Regioselective para‐Carboxylation of Catechols with a Prenylated Flavin Dependent Decarboxylase
Authors: Payer Stefan E. , Marshall Stephen A. , Bärland Natalie , Sheng Xiang , Reiter Tamara , Dordic Andela , Steinkellner Georg , Wuensch Christiane , Kaltwasser Susann , Fisher Karl , Rigby Stephen E. J. , Macheroux Peter , Vonck Janet , Gruber Karl , Faber Kurt , Himo Fahmi , Leys David , Pavkov‐Keller Tea , Glueck Silvia M. 
Published: August 2017

AbstractThe utilization of CO2 as a carbon source for organic synthesis meets the urgent demand for more sustainability in the production of chemicals. Herein, we report on the enzyme‐catalyzed para‐carboxylation of catechols, employing 3,4‐dihydroxybenzoic acid decarboxylases (AroY) that belong to the UbiD enzyme family. Crystal structures and accompanying solution data confirmed that AroY utilizes the recently discovered prenylated FMN (prFMN) cofactor, and requires oxidative maturation to form the catalytically competent prFMNiminium species. This study reports on the in vitro reconstitution and activation of a prFMN‐dependent enzyme that is capable of directly carboxylating aromatic catechol substrates under ambient conditions. A reaction mechanism for the reversible decarboxylation involving an intermediate with a single covalent bond between a quinoid adduct and cofactor is proposed, which is distinct from the mechanism of prFMN‐associated 1,3‐dipolar cycloadditions in related enzymes.
Iminophosphine palladium catalysts for Suzuki carbonylative coupling reaction
Authors: Yılmaz Mustafa Kemal , Keleş Hülya , İnce Simay , Keleş Mustafa 
Published: August 2017

Three iminophosphine ligands having soft phosphorus and hard nitrogen atoms and their Pd(II) complexes were synthesized and characterized using 1H NMR, 13C NMR, 31P NMR and Fourier transform infrared spectroscopic techniques. Also, electrochemical properties of the iminophosphines and their Pd(II) complexes were investigated in acetonitrile–tetrabutylammonium perchlorate solution with cyclic and square wave voltammetry techniques. All Pd(II) complexes were evaluated as catalysts for carbonylative cross‐coupling reactions of aryl iodides with phenylboronic acid. The Suzuki carbonylation of aryl iodides at 80 °C under balloon pressure of carbon monoxide in the presence of K2CO3 as a base was examined, and good to high conversions and excellent selectivities were obtained.
Microstructural and mechanical property evolutions of shape memory polyurethane during a thermodynamic cycle
Authors: Shi Shuang , Shen Dongya , Xu Tao 
Published: August 2017

ABSTRACTTo better understand the shape memory behaviors of synthesized shape memory polyurethane (SMPU) sealant with a tailored transition temperature (Tt) for concrete pavement joints, the thermal and dynamic mechanical properties of SMPU were first characterized to determine the shape memory switching temperature of SMPU. Then the microstructural and mechanical property evolutions of SMPU in the original, programmed, and recovered states during a five‐step thermodynamic cycle were discussed, respectively. The results indicate that the tailored Tt of prepared SMPU can be used as the shape memory switching temperature to match its working temperature. Further, the programming causes the phase separation in SMPU, leading to an obvious anisotropy. The SMPU has satisfactory shape memory performance. The orientation of molecular chains in soft segments is confirmed along the stretching direction. The oriented molecular chains can restore to the naturally curled state during the free recovery. Finally, the programming improves the mechanical properties of SMPU. The recovered SMPU shows a slight decrease in mechanical properties because of the partially impaired crystal structures and broken molecular segments during the programming and recovery. It is concluded that the synthesized SMPU with the specially tailored Tt is suitable to use as a sealant of concrete pavement joints. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45703.
Assessing the importance of net colour as a seabird bycatch mitigation measure in gillnet fishing
Authors: Hanamseth Roshan , Barry Baker G. , Sherwen Sally , Hindell Mark , Lea Mary‐Anne 
Published: August 2017

Abstract

Gillnets are used widely in fisheries throughout the world and known to cause the death of thousands of seabirds each year. Currently few practical or technical options are available to fishers for preventing seabird mortalities.
The ability of little penguins (Eudyptula minor) to differentiate between different coloured netting materials was tested under controlled conditions to ascertain if changes in gillnet colour could facilitate a potential mitigation measure by improving visibility of nets.
The study involved a repeated‐measures design with penguins exposed to variously coloured mono‐filament threads creating a gillnet mimic. The gillnet mimic was made up of gillnet material configured as a series of vertical lines 25 mm apart stretched tightly across a stainless steel frame that measured 1160 mm × 1540 mm and divided into two equal panel areas. The panels were placed in a large tank within an enclosure that housed 25 penguins. Penguins were able to readily access the tank and swim freely. The frame was always introduced into the tank with one panel containing a gillnet mimic, and the other panel left empty as a control.
Gillnet filament colours tested were clear, green and orange. Orange coloured monofilament lines resulted in lower collision rates (5.5%), while clear and green monofilament lines resulted in higher rates of collision (35.9% and 30.8%, respectively).
These results suggest that orange‐coloured lines were more apparent to the birds. Constructing nets of orange‐coloured material may be effective in reducing bycatch in gillnets set in shallow waters and high light levels where seabirds are able to identify fine colour differences.
Further testing under experimental conditions, accompanied with at‐sea trials to verify effectiveness in varied light conditions is warranted, together with an assessment of the effect of gillnet colour on catch efficiency of target species.
Re‐introduction of structurally complex wood jams promotes channel and habitat recovery from overwidening: Implications for river conservation
Authors: Harvey Gemma L. , Henshaw Alexander J. , Parker Chris , Sayer Carl D. 
Published: August 2017

Abstract

Large wood is a powerful geomorphic agent in rivers, providing important habitat functions for a range of aquatic organisms, but has been subject to a long history of removal.
Internationally, approaches to river restoration are increasingly incorporating large wood features, but generally favour simple flow deflectors (e.g. single logs, stripped of branches and anchored in place) over more complex structures that more accurately mimic natural wood jams.
This paper explores channel response to wood‐based restoration of an overwidened lowland chalk stream that incorporated whole felled trees. Hydraulics, sediment, topography and vegetation data were assessed for a 3 year period for two restored reaches: an upstream reach where pre‐restoration baseline data were obtained, and a downstream reach restored before data collection.
Where pre‐restoration data were available, the introduction of wood jams generated sediment deposition within jams leading to the development of vegetated marginal ‘benches’ and bed scour in adjacent areas of flow convergence. Patterns were less clear in the downstream reach, where restoration design was less ambitious and outcomes may have been affected by subsequent restoration work upstream.
The results indicate that reintroduction of large wood (whole trees), can promote channel and habitat recovery from overwidening in lowland rivers, creating important ecological benefits through the provision of structurally complex marginal habitat and associated food resources. Longer‐term assessments are required to establish whether the trajectories of change are persistent.
The work emphasizes the effectiveness of restoration approaches that aim to ‘work with nature’. The ambitious design, incorporating structurally complex wood jams, was also low‐cost, using materials available from the river corridor (existing riparian trees). Furthermore, ecosystem engineering effects were amplified by the colonization of wood jams by aquatic vegetation. The approach should, therefore, be transferable to other lowland rivers, subject to wider catchment constraints.