bluuebunny/crossref_metadata_2025_split huggingface dataset:
Climatic controls on debris‐flow activity and sediment aggradation: The Del Medio fan, NW Argentina
Authors: Savi Sara , Schildgen Taylor F. , Tofelde Stefanie , Wittmann Hella , Scherler Dirk , Mey Jürgen , Alonso Ricardo N. , Strecker Manfred R. 
Published: November 2016

AbstractIn the Central Andes, several studies on alluvial terraces and valley fills have linked sediment aggradation to periods of enhanced sediment supply. However, debate continues over whether tectonic or climatic factors are most important in triggering the enhanced supply. The Del Medio catchment in the Humahuaca Basin (Eastern Cordillera, NW Argentina) is located within a transition zone between subhumid and arid climates and hosts the only active debris‐flow fan within this intermontane valley. By combining 10Be analyses of boulder and sediment samples within the Del Medio catchment, with regional morphometric measurements of nearby catchments, we identify the surface processes responsible for aggradation in the Del Medio fan and their likely triggers. We find that the fan surface has been shaped by debris flows and channel avulsions during the last 400 years. Among potential tectonic, climatic, and autogenic factors that might influence deposition, our analyses point to a combination of several favorable factors that drive aggradation. These are in particular the impact of occasional abundant rainfall on steep slopes in rock types prone to failure, located in a region characterized by relatively low rainfall amounts and limited transport capacity. These characteristics are primarily associated with the climatic transition zone between the humid foreland and the arid orogen interior, which creates an imbalance between sediment supply and sediment transfer. The conditions and processes that drive aggradation in the Del Medio catchment today may provide a modern analog for the conditions and processes that drove aggradation in other nearby tributaries in the past.
Stereocontrolled [4+1] Annulation of α‐Hydroxycyclobutenones: Synthesis of Polysubstituted Cyclopentenones
Authors: Mao Xu , Song Peidong , Hao Yu , Sun Zezhong , Hu Xiangdong 
Published: November 2016

AbstractA stereocontrolled [4+1] annulation of α‐hydroxycyclobutenones has been disclosed. For the first time, α‐hydroxycyclobutenones have been proven as facile diene precursors for [4+1] annulation. Meanwhile, the reported transformation presents a concise synthetic route to polysubstituted cyclopentenones with high stereoselectivity.magnified image
Copper‐Catalyzed Allenylation‐Isomerization Sequence of Penta‐1,4‐diyn‐3‐yl Acetates with P(O)H Compounds: Facile Synthesis of 1‐Phosphonyl 2,4‐Diynes
Authors: Shen Ruwei , Yang Jianlin , Luo Bing , Zhang Lixiong , Han Li‐Biao 
Published: November 2016

AbstractThe copper‐catalyzed reaction of 5‐substituted penta‐1,4‐diyn‐3‐yl acetates with P(O)H compounds to efficiently give a new class of phosphonyl diynes is reported. The reaction may take place through a regioselective nucleophilic attack of phosphorus nucleophiles on Cu‐allenylidene intermediates to form allenyl intermediates followed by a rapid allene‐alkyne isomerization process. The synthetic utility of the obtained products is demonstrated.magnified image
Catalyst‐Controlled Regiodivergent Dehydrogenative Heck Reaction of 4‐Arylthiophene/Furan‐3‐Carboxylates
Authors: Gao Shang , Wu Zijun , Wu Fei , Lin Aijun , Yao Hequan 
Published: November 2016

AbstractA catalyst‐controlled regiodivergent dehydrogenative Heck reaction of 4‐arylthiophene/furan‐3‐carboxylates has been realized. Use of a palladium catalyst led to the C‐5 alkenylation through electronic palladation, while a ruthenium catalyst favored the C‐2 alkenylation with the assistance of a directing group. This reaction exhibited good to excellent regioselectivities.magnified image
Copper(I) Iodide‐Catalyzed Sulfenylation of Maleimides and Related 3‐Indolylmaleimides with Thiols
Authors: Yang Zhen‐Hua , An Yu‐Long , Chen Ying , Shao Zhi‐Yu , Zhao Sheng‐Yin 
Published: November 2016

AbstractAn efficient copper(I) iodide‐catalyzed sulfenylation of maleimides and related 3‐indolylmaleimides with thiols has been developed in the presence of fluoroboric acid. Several 3‐thiomaleimides and 3‐indolyl‐4‐thiomaleimides were obtained with good yields under ligand‐free conditions. The methods are simple, practical and show good functional group tolerance.magnified image
Copper(II)‐Catalyzed Asymmetric 1,3‐Dipolar [3+4] Cycloaddition and Kinetic Resolution of Azomethine Imines with Azoalkenes
Authors: Wei Liang , Wang Zuo‐Fei , Yao Lu , Qiu Guofu , Tao Haiyan , Li Hua , Wang Chun‐Jiang 
Published: November 2016

AbstractAn unprecedented copper(II)‐catalyzed enantioselective 1,3‐dipolar [3+4] cycloaddition of azomethine imines with in situ formed azoalkenes has been realized. This strategy provides a facile access to biologically important 1,2,4,5‐tetrazepine derivatives in high yield with exclusive regioselectivity and high stereoselectivity. Moreover, enantioenriched azomethine imines could be obtained via an efficient kinetic resolution using the same approach.magnified image
Stochastic phenomena in a fiber Raman amplifier
Authors: Kalashnikov Vladimir , Sergeyev Sergey V. , Ania‐Castanón Juan Diego , Jacobsen Gunnar , Popov Sergei 
Published: November 2016

The interplay of such cornerstones of modern nonlinear fiber optics as a nonlinearity, stochasticity and polarization leads to variety of the noise induced instabilities including polarization attraction and escape phenomena harnessing of which is a key to unlocking the fiber optic systems specifications required in high resolution spectroscopy, metrology, biomedicine and telecommunications. Here, by using direct stochastic modeling, the mapping of interplay of the Raman scattering‐based nonlinearity, the random birefringence of a fiber, and the pump‐to‐signal intensity noise transfer has been done in terms of the fiber Raman amplifier parameters, namely polarization mode dispersion, the relative intensity noise of the pump laser, fiber length, and the signal power. The obtained results reveal conditions for emergence of the random birefringence‐induced resonance‐like enhancement of the gain fluctuations (stochastic anti‐resonance) accompanied by pulse broadening and rare events in the form of low power output signals having probability heavily deviated from the Gaussian distribution.
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Struktur eines monomeren Transthyretin mit der klinisch wichtigen T119M‐Mutation
Authors: Kim Jin Hae , Oroz Javier , Zweckstetter Markus 
Published: November 2016

AbstractMutationen im Protein Transthyretin können Transthyretin‐Amyloidose hervorrufen sowie Individuen davor schützen. Wenig ist jedoch über die strukturelle Basis pathogener und klinisch schützender Transthyretin‐Mutanten bekannt. Hier berichten wir über die Lösungsstruktur eines Transthyretin‐Monomers, das die klinisch wichtige T119M‐Mutation trägt. Die Struktur offenbart eine nichtnative Anordnung, die sich von allen bekannten Transthyretin‐Strukturen unterscheidet, und unterstreicht die Bedeutung von Lösungsstudien mit hoher Auflösung, um molekulare Prozesse zu verstehen, die zu Amyloid‐Erkrankungen führen.
Ein stabil protoniertes Adenin‐Nukleotid mit einem extrem verschobenen pKa‐Wert stabilisiert die Tertiärstruktur eines GTP‐bindenden RNA‐Aptamers
Authors: Wolter Antje C. , Weickhmann A. Katharina , Nasiri Amir H. , Hantke Katharina , Ohlenschläger Oliver , Wunderlich Christoph H. , Kreutz Christoph , Duchardt‐Ferner Elke , Wöhnert Jens 
Published: November 2016

AbstractRNA‐Tertiärstrukturmotive werden durch viele verschiedene Wasserstoffbrücken stabilisiert. Protonierte A‐ und C‐Nukleotide werden normalerweise nicht als geeignete Bausteine für solche Motive betrachtet, da ihre pKa‐Werte weit vom physiologischen pH‐Wert entfernt sind. Hier beschreiben wir die NMR‐Struktur eines in vitro selektierten GTP‐bindenden RNA‐Aptamers gebunden an GTP mit einer sehr komplexen Tertiärstruktur. Es enthält ein neuartiges, durch ein protoniertes A stabilisiertes Basenquartett. Aufgrund der besonderen strukturellen Umgebung innerhalb des Basenquartetts im GTP‐Komplex ist der pKa‐Wert für die Protonierung dieses A‐Nukleotides im Vergleich zum pKa‐Wert für A‐Nukleotide in einzelsträngiger RNA um mehr als fünf pH‐Einheiten verschoben. Dies ist die größte bisher beschriebene Verschiebung des pKa‐Wertes für ein A in strukturierten Nukleinsäuren. Sowohl die Vorfaltung der RNA als auch die Ligandenbindung tragen zu dieser Verschiebung des pKa‐Wertes bei.
Variable Time Normalization Analysis: General Graphical Elucidation of Reaction Orders from Concentration Profiles
Authors: Burés Jordi 
Published: November 2016

AbstractThe recent technological evolution of reaction monitoring techniques has not been paralleled by the development of modern kinetic analyses. The analyses currently used disregard part of the data acquired, thus requiring an increased number of experiments to obtain sufficient kinetic information for a given chemical reaction. Herein, we present a simple graphical analysis method that takes advantage of the data‐rich results provided by modern reaction monitoring tools. This analysis uses a variable normalization of the time scale to enable the visual comparison of entire concentration reaction profiles. As a result, the order in each component of the reaction, as well as kobs , is determined with just a few experiments using a simple and quick mathematical data treatment. This analysis facilitates the rapid extraction of relevant kinetic information and will be a valuable tool for the study of reaction mechanisms.
Structure of Monomeric Transthyretin Carrying the Clinically Important T119M Mutation
Authors: Kim Jin Hae , Oroz Javier , Zweckstetter Markus 
Published: November 2016

AbstractMutations in the protein transthyretin can cause as well as protect individuals from transthyretin amyloidosis, an incurable fatal inherited disease. Little is known, however, about the structural basis of pathogenic and clinically protective transthyretin mutants. Here we determined the solution structure of a transthyretin monomer that carries the clinically important T119M mutation. The structure displays a non‐native arrangement that is distinct from all known structures of transthyretin and highlights the importance of high‐resolution studies in solution for understanding molecular processes that lead to amyloid diseases.
A Stably Protonated Adenine Nucleotide with a Highly Shifted pKa Value Stabilizes the Tertiary Structure of a GTP‐Binding RNA Aptamer
Authors: Wolter Antje C. , Weickhmann A. Katharina , Nasiri Amir H. , Hantke Katharina , Ohlenschläger Oliver , Wunderlich Christoph H. , Kreutz Christoph , Duchardt‐Ferner Elke , Wöhnert Jens 
Published: November 2016

AbstractRNA tertiary structure motifs are stabilized by a wide variety of hydrogen‐bonding interactions. Protonated A and C nucleotides are normally not considered to be suitable building blocks for such motifs since their pKa values are far from physiological pH. Here, we report the NMR solution structure of an in vitro selected GTP‐binding RNA aptamer bound to GTP with an intricate tertiary structure. It contains a novel kind of base quartet stabilized by a protonated A residue. Owing to its unique structural environment in the base quartet, the pKa value for the protonation of this A residue in the complex is shifted by more than 5 pH units compared to the pKa for A nucleotides in single‐stranded RNA. This is the largest pKa shift for an A residue in structured nucleic acids reported so far, and similar in size to the largest pKa shifts observed for amino acid side chains in proteins. Both RNA pre‐folding and ligand binding contribute to the pKa shift.
Synthesis and Investigation of Advanced Energetic Materials Based on Bispyrazolylmethanes
Authors: Fischer Dennis , Gottfried Jennifer L. , Klapötke Thomas M. , Karaghiosoff Konstantin , Stierstorfer Jörg , Witkowski Tomasz G. 
Published: November 2016

AbstractHerein we present the preparation and characterization of three new bispyrazolyl‐based energetic compounds with great potential as explosive materials. The reaction of sodium 4‐amino‐3,5‐dinitropyrazolate (5) with dimethyl iodide yielded bis(4‐amino‐3,5‐dinitropyrazolyl)methane (6), which is a secondary explosive with high heat resistance (Tdec=310 °C). The oxidation of this compound afforded bis(3,4,5‐trinitropyrazolyl)methane (7), which is a combined nitrogen‐ and oxygen‐rich secondary explosive with very high theoretical and estimated experimental detonation performance (Vdet (theor)=9304 m s−1 versus Vdet(exp)=9910 m s−1) in the range of that of CL‐20. Also, the thermal stability (Tdec=205 °C) and sensitivities of 7 are auspicious. The reaction of 6 with in situ generated nitrous acid yielded the primary explosive bis(4‐diazo‐5‐nitro‐3‐oxopyrazolyl)methane (8), which showed superior properties to those of currently used diazodinitrophenol (DDNP).
Processing and mechanical properties of bio‐derived vinyl ester resin‐based composites
Authors: Shah Priyank N. , Dev Siddharth , Lee Yongwoo , Hansen Christopher J. 
Published: November 2016

ABSTRACTA “green” vinyl ester resin (GVER) is investigated for use in structural applications. The GVER was formulated using a monodisperse vinyl ester created via a novel synthetic route capable of using bio‐waste material from paper and biodiesel industries. The GVER was used either as a neat resin or as blended with a commercial vinyl ester resin. The processing viscosity and gel times are investigated. The GVER reaches a similar viscosity as the commercial resin with only half the styrene monomer content, thereby reducing the volatile organic compounds associated with manufacturing. Composites of the GVER matrix reinforced by carbon fabric were tested for their tensile and flexural properties. The mechanical performance of the GVER compares favorably with commercial resin and provide a route for composites manufacturing from sustainably sourced vinyl ester matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44642.
Self‐driven graft polymerization of vinyl monomers on poultry chicken feathers in the absence of initiator/catalyst
Authors: Patnam Padma L. , Ray Siddharth S. , Chatterjee Alok K. , Jain Suman L. 
Published: November 2016

ABSTRACTAn efficient and simple method for graft copolymerization of powdered chicken feather (CF) with vinyl monomers without any free radical initiator is reported. Various vinyl monomers such as glycidyl methacrylate (GMA), styrene (S), and methyl methacrylate (MMA); (20–60 wt % with respect to CF) were successfully grafted to chicken feather (CF) by using sodium dodecyl sulfate (SDS, 0.086–0.5 mmol) in the absence of any catalyst or initiator. Most likely, the hydrophilicity, hydrophobicity, and complex forming properties of chicken feather keratin with surfactant molecules were responsible for efficient grafting of polymers on CF surface. The effect of polymerization conditions, such as monomer concentration, temperature, and time of reaction, on the grafting parameters such as monomer conversion, grafting efficiency, and molar grafting ratio were studied. The described method showed a good potential of using low cost, easily accessible poultry chicken feathers as grafting material and self catalyzing agent for graft copolymerization with vinyl monomers to produce low cost commodity plastic for various end uses. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44645.
Superionic Conductivity in Hybrid of 3‐Hydroxypropanesulfonic Acid and Graphene Oxide
Authors: Wakata Kosuke , Karim Mohammad Razaul , Islam Md. Saidul , Ohtani Ryo , Nakamura Masaaki , Koinuma Michio , Hayami Shinya 
Published: November 2016

AbstractInsertion of 3‐hydroxypropanesulfonicacid (HPS) in the graphene oxide (GO) interlayer results in high proton conductivity (10−2–10−1 S cm−1), owing to an improvement in oxygen content, interlayer distance and water absorbing capacity. This result indicates that hydroxyalkylsulfonicacids can be perfect guest molecules for improving the proton conductivity of carbon materials.
Trusting me, trusting you: Evaluating three forms of trust on an information‐rich consumer review website
Authors: Duffy Andrew 
Published: November 2016

AbstractWhen faced with a lack of information, consumers turn to trust to make a decision; but what happens to trust when individuals are confronted with the wealth of data on the Internet? This study evaluates three forms of trust in information‐abundant contexts: trust in the site, trust in the reviewers, and a postulated third form, trust‐in‐self. It looks at the roles of these three forms of trust in the information‐rich travel review website TripAdvisor. Two studies of site users, interviews (N = 30) and a survey (N = 237), found trust‐in‐self was highly influential in purchase decision making. Further, even with so much information, consumers sought more; the site is just one source they turn to, and they cross‐check among sources. The study concludes that any trust consumers have in TripAdvisor is not so much in the reviewers or the site, but in their own selves. Copyright © 2016 John Wiley & Sons, Ltd.
Influence of Preparation Method on Size Distribution of the Dispersed Phase of Primary Emulsions
Authors: Kulawik‐Pióro Agnieszka , Tal‐Figiel Barbara 
Published: November 2016

AbstractThe distribution and size of dispersed‐phase droplets impacts the most important parameters of fast disintegrating tablets including their bioavailability. The fact that after reconstruction the most emulsion droplets are bigger than those of primary emulsions led to a study of innovative emulsification techniques, like ultrasonic energy, mechanical mixing, and a combined technique of homogenization and ultrasonic energy. Taking the size of dispersed‐phase droplets as criterion of effectiveness for a procedure to create a primary emulsion, it can be concluded that the proposed emulsification methods of ultrasonic energy and combined technique are not suitable for water phases containing hydrocolloids such as gums.
Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence
Authors: Bosson Johann , Labrador Geraldine M. , Pascal Simon , Miannay François‐Alexandre , Yushchenko Oleksandr , Li Haidong , Bouffier Laurent , Sojic Neso , Tovar Roberto C. , Muller Gilles , Jacquemin Denis , Laurent Adèle D. , Le Guennic Boris , Vauthey Eric , Lacour Jérôme 
Published: November 2016

AbstractThe physicochemical properties of cationic dioxa (1), azaoxa (2), and diaza (3) [6]helicenes demonstrate a much higher chemical stability of the diaza adduct 3 (pKR+=20.4,
=−0.72 V) compared to its azaoxa 2 (pKR+=15.2,
=−0.45 V) and dioxa 1 (pKR+=8.8,
=−0.12 V) analogues. The fluorescence of these cationic chromophores is established, and ranges from the orange to the far‐red regions. From 1 to 3, a bathochromic shift of the lowest energy transitions (up to 614 nm in acetonitrile) and an enhancement of the fluorescence quantum yields and lifetimes (up to 31 % and 9.8 ns, respectively, at 658 nm) are observed. The triplet quantum yields and circularly polarized luminescence are also reported. Finally, fine tuning of the optical properties of the diaza [6]helicene core is achieved through selective and orthogonal post‐functionalization reactions (12 examples, compounds 4–15). The electronic absorption is modulated from the orange to the far‐red spectral range (560–731 nm), and fluorescence is observed from 591 to 755 nm with enhanced quantum efficiency up to 70 % (619 nm). The influence of the peripheral auxochrome substituents is rationalized by first‐principles calculations.
Tuning the Energy Transfer Efficiency between Ce3+ and Ln3+ Ions (Ln=Tm, Sm, Tb, Dy) by Controlling the Crystal Phase of NaYF4 Nanocrystals
Authors: Adusumalli Venkata N. K. B. , Koppisetti Heramba V. S. R. M. , Ganguli Sagar , Sarkar Shyam , Mahalingam Venkataramanan 
Published: December 2016

AbstractNaYF4 is a superior host matrix to study the luminescence properties of lanthanide (Ln3+) ions. Ln3+ ions in hexagonal‐phase NaYF4 (β‐phase) nanocrystals (NCs) exhibit strong luminescence via an upconversion process compared to cubic NaYF4 (α‐phase) NCs. However, in Ce3+/Ln3+‐doped NaYF4 NCs (Ln=Tm, Tb, Sm, Dy) the α‐phase NaYF4 NCs shows strong luminescence compared to their counterpart β‐phase NCs despite the latter being much larger in size. This is attributed to comparatively large overlap between Ce3+ ions emission band with excited energy levels of those Ln3+ ions in α‐phase compared to β‐phase NCs. This difference is attributed to different crystal‐field splitting of Ce3+ ions 4f–5d band in different crystal environments of the α‐phase (cubic crystal field environment) and β‐phase (trigonal prismatic with equatorials crystal field environment) NaYF4 NCs with respect to their barycenter. The enhanced luminescence from α‐phase NaYF4 NCs is advantageous as they are prepared at a relatively lower temperature and shorter reaction times compared to β‐NaYF4 NCs.
Physicochemical and Electronic Properties of Cationic [6]Helicenes: from Chemical and Electrochemical Stabilities to Far‐Red (Polarized) Luminescence
Authors: Bosson Johann , Labrador Geraldine M. , Pascal Simon , Miannay François‐Alexandre , Yushchenko Oleksandr , Li Haidong , Bouffier Laurent , Sojic Neso , Tovar Roberto C. , Muller Gilles , Jacquemin Denis , Laurent Adèle D. , Le Guennic Boris , Vauthey Eric , Lacour Jérôme 
Published: November 2016

AbstractInvited for the cover of this issue is the group of Eric Vauthey and Jérôme Lacour. The image depicts a chiral cationic [6]helicene, which is a powerful dye and fluorophore emitting circularly polarized light in the red to far red region. Read the full text of the article at 10.1002/chem.201603591.
From Type I to Type II: Design, Synthesis, and Characterization of Potent Pyrazin‐2‐ones as DFG‐Out Inhibitors of PDGFRβ
Authors: Bethke Eugen , Pinchuk Boris , Renn Christian , Witt Lydia , Schlosser Joachim , Peifer Christian 
Published: November 2016

AbstractReversible protein kinase inhibitors that bind in the ATP cleft can be classified as type I or type II binders. Of these, type I inhibitors address the active form, whereas type II inhibitors typically lock the kinase in an inactive form. At the molecular level, the conformation of the flexible activation loop holding the key DFG motif controls access to the ATP site, thereby determining an active or inactive kinase state. Accordingly, type I and type II kinase inhibitors bind to so‐called DFG‐in or DFG‐out conformations, respectively. Based on our former study on highly selective platelet‐derived growth factor receptor β (PDGFRβ) pyrazin‐2‐one type I inhibitors, we expanded this scaffold toward the deep pocket, yielding the highly potent and effective type II inhibitor 5 (4‐[(4‐methylpiperazin‐1‐yl)methyl]‐N‐[3‐[[6‐oxo‐5‐(3,4,5‐trimethoxyphenyl)‐1H‐pyrazin‐3‐yl]methyl]phenyl]benzamide). In vitro characterization, including selectivity panel data from activity‐based assays (300 kinases) and affinity‐based assays (97 kinases) of these PDGFRβ type I (1; 5‐(4‐hydroxy‐3‐methoxy‐phenyl)‐3‐(3,4,5‐trimethoxyphenyl)‐1H‐pyrazin‐2‐one) and II (5) inhibitors showing the same pyrazin‐2‐one chemotype are compared. Implications are discussed regarding the data for selectivity and efficacy of type I and type II ligands.