bluuebunny/crossref_metadata_2025_split huggingface dataset:
Southeast Papuan crustal tectonics: Imaging extension and buoyancy of an active rift
Authors: Abers G. A. , Eilon Z. , Gaherty J. B. , Jin G. , Kim YH. , Obrebski M. , Dieck C. 
Published: January 2016

AbstractSoutheast Papua hosts the world's youngest ultra‐high‐pressure (UHP) metamorphic rocks. These rocks are found in an extensional setting in metamorphic core complexes. Competing theories of extensional shear zones or diapiric upwelling have been suggested as driving their exhumation. To test these theories, we analyze the CDPAPUA temporary array of 31 land and 8 seafloor broadband seismographs. Seismicity shows that deformation is being actively accommodated on the core complex bounding faults, offset by transfer structures in a manner consistent with overall north‐south extension rather than radial deformation. Rayleigh wave dispersion curves are jointly inverted with receiver functions for crustal velocity structure. They show crustal thinning beneath the core complexes of 30–50% and very low shear velocities at all depths beneath the core complexes. On the rift flanks velocities resemble those of normal continents and increase steadily with depth. There is no evidence for velocity inversions that would indicate that a major density inversion exists to drive crustal diapirs. Also, low‐density melt seems minor within the crust. Together with the extension patterns apparent in seismicity, these data favor an extensional origin for the core complexes and limit the role of diapirism as a secondary exhumation mechanism, although deeper mantle diapirs may be undetected. A small number of intermediate‐depth earthquakes, up to 120 km deep, are identified for the first time just northeast of the D'Entrecasteaux Islands. They occur at depths similar to those recorded by UHP rocks and similar temperatures, indicating that the modern seismicity occurs at the setting that generates UHP metamorphism.
Synthesis of Substituted Quinolizidines via a Gold‐Catalyzed Double Cyclization Cascade
Authors: Nonaka Shiori , Sugimoto Kenji , Ueda Hirofumi , Tokuyama Hidetoshi 
Published: January 2016

AbstractA novel synthesis of quinolizidines by a cationic gold‐catalyzed double cyclization cascade has been developed. The reaction was initiated by the gold‐catalyzed 6‐exo‐dig cyclization of ynamides, which was followed by a second cyclization of an enamide intermediate to provide the corresponding quinolizidine derivatives. The utility of this reaction was demonstrated by application to the synthesis of multi‐substituted quinolizidines and by the total synthesis of a quinolizidine alkaloid, (±)‐lupinine.magnified image
Towards Keratan Sulfate – Chemoenzymatic Cascade Synthesis of Sulfated N‐Acetyllactosamine (LacNAc) Glycan Oligomers
Authors: Lange Bastian , Šimonová Anna , Fischöder Thomas , Pelantová Helena , Křen Vladimír , Elling Lothar 
Published: January 2016

AbstractWe report on a novel chemoenzymatic cascade for the synthesis of sulfated N‐acetyllactosamine [(3Galβ1,4GlcNAcβ1,)n, LacNAc] oligomer structures. Starting from a linker modified GlcNAc substrate di‐ and trisaccharides were first synthesized by sequential use of human β4‐galactosyltransferase‐1 (β4GalT‐1) and β3‐N‐acetylglucosaminyltransferase from Helicobacter pylori (β3GlcNAcT). Subsequent regioselective chemical sulfation rendered the C‐6 mono‐, di‐, and tri‐O‐sulfated products in good yields. Further enzymatic elongation by β4GalT‐1 and β3GlcNAcT in a sequential mode yielded 6‐O‐sulfated LacNAc oligomers up to hexasaccharide length with variable degrees of sulfation. These carbohydrate structures mimic the sulfation pattern found in keratan sulfate and are potential ligands for different classes of glycan binding proteins.magnified image
Copper‐Nitrene Triggered Annulation of α‐Acyl Cinnamides: Access to Isoxazol‐3(2H)‐ones
Authors: Yu Mangfei , Zhang Qian , Li Gong , Yuan Jingwen , Zhang Ning , Zhang Rui , Liang Yongjiu , Dong Dewen 
Published: January 2016

AbstractA facile and efficient one‐pot synthesis of isoxazol‐3(2H)‐ones has been developed starting from α‐acyl cinnamides and tosyliminophenyliodinane catalyzed by copper(II) acetate [Cu(OAc)2] under very mild conditions involving a tandem aza‐Michael addition and intramolecular cyclization sequence.magnified image
The Applications of Dimethyl Sulfoxide as Reagent in Organic Synthesis
Authors: Wu Xiao‐Feng , Natte Kishore 
Published: January 2016

AbstractDimethyl sulfoxide (DMSO) is one of the most commonly applied organic solvents in chemical transformations and is utilized widely in industrial processes as well. During the past decades, numerous procedures using DMSO as a reaction reagent have been developed and published. In this review, the main developments on the employment of DMSO as sources of Me, SMe, SO2Me, as an oxidant etc. have been summarized and discussed.magnified image
Is the twin‐singleton difference in BMI related to the difference in birth weight? A register‐based birth cohort study of Norwegian males
Authors: Eriksen Willy , Tambs Kristian 
Published: January 2016

ObjectiveThe aim was to test the hypothesis that the difference in body mass index (BMI) between twins and singletons may be attributed to a difference in birth weight.MethodsData from the Medical Birth Registry of Norway were linked with data from the Norwegian Conscript Service. This study used data on 411,186 males who were born in single or twin births in Norway during 1967 to 1984, and who were examined at the mandatory military conscription (98% were examined the year they turned 18 or 19 years of age).ResultsThe difference in BMI between singletons and twins was 0.49 kg/m2 (95% confidence interval [CI]: 0.41, 0.56) after adjustment for background factors and gestational age at birth. When birth weight was added to the model, the difference was reduced to 0.17 kg/m2 (95% CI: 0.09, 0.25). The corresponding figures for sibships that included both singletons and twins were 0.63 kg/m2 (95% CI: 0.39, 0.86) and 0.38 kg/m2 (95% CI: 0.06, 0.70) when twins were compared with their singleton brothers. In both the analysis of the total study population and the analysis of the sibships, birth weight was significantly associated with the BMI after adjustment for twin status, gestational age at birth, and background factors.ConclusionsMale twins born in Norway during 1967 to 1984 had lower BMI at the military conscription than had singletons, and a part of this difference may probably be attributed to lower intrauterine growth rate among twins. Am. J. Hum. Biol. 28:566–573, 2016. © 2016 Wiley Periodicals, Inc.
Two‐Step Synthesis of a Clickable Photoaffinity Probe from an Anticancer Saponin OSW‐1 and its Photochemical Reactivity
Authors: Yamada Rika , Hiraizumi Masato , Narita Sho , Sakurai Kaori 
Published: January 2016

AbstractOSW‐1 is a highly potent anticancer saponin with an unknown mechanism of action that is distinct from the currently used chemotherapeutic agents. Toward investigation of its binding proteins, we designed and synthesized a clickable photoaffinity probe from OSW‐1 and characterized its photochemical reactivity. A mild, two‐step procedure involving a Me2SnCl2‐mediated acylation reaction was developed to site‐selectively derivatize OSW‐1 with a linker that bears a photoreactive group and an alkyne tag. The OSW‐1‐based photoaffinity probe retained potent anticancer activity similar to that of the parent natural product, thereby providing a cell‐permeable analogue of OSW‐1. Photoaffinity labeling studies demonstrated that the probe enabled crosslinking of a model sterol‐binding protein in an affinity‐dependent fashion, which could be efficiently detected by conjugating a fluorophore or biotin by click chemistry.
Deciphering diet and monitoring movement: Multiple stable isotope analysis of the viking age settlement at Hofstaðir, Lake Mývatn, Iceland
Authors: Sayle Kerry L. , Hamilton W. Derek , Cook Gordon T. , Ascough Philippa L. , Gestsdóttir Hildur , McGovern Thomas H. 
Published: January 2016

ABSTRACTObjectivesA previous multi‐isotope study of archaeological faunal samples from Skútustaðir, an early Viking age settlement on the southern shores of Lake Mývatn in north‐east Iceland, demonstrated that there are clear differences in δ34S stable isotope values between animals deriving their dietary protein from terrestrial, freshwater, and marine reservoirs. The aim of this study was to use this information to more accurately determine the diet of humans excavated from a nearby late Viking age churchyard.Materials and Methodsδ13C, δ15N, and δ34S analyses were undertaken on terrestrial animal (n = 39) and human (n = 46) bone collagen from Hofstaðir, a high‐status Viking‐period farmstead ∼10 km north‐west of Skútustaðir.Resultsδ34S values for Hofstaðir herbivores were ∼6‰ higher relative to those from Skútustaðir (δ34S: 11.4 ± 2.3‰ versus 5.6 ± 2.8‰), while human δ13C, δ15N, and δ34S values were broad ranging (−20.2‰ to −17.3‰, 7.4‰ to 12.3‰, and 5.5‰ to 14.9‰, respectively).DiscussionResults suggest that the baseline δ34S value for the Mývatn region is higher than previously predicted due to a possible sea‐spray effect, but the massive deposition of Tanytarsus gracilentus (midges) (δ34S: −3.9‰) in the soil in the immediate vicinity of the lake is potentially lowering this value. Several terrestrial herbivores displayed higher bone collagen δ34S values than their contemporaries, suggesting trade and/or movement of animals to the region from coastal areas. Broad ranging δ13C, δ15N, and δ34S values for humans suggest the population were consuming varied diets, while outliers within the dataset could conceivably have been migrants to the area. Am J Phys Anthropol 160:126–136, 2016. © 2016 Wiley Periodicals, Inc.
Elektrospray‐Massenspektrometrie: ein umgekehrtes Periskop zur Erforschung von Reaktionsmechanismen in Lösung
Authors: Iacobucci Claudio , Reale Samantha , De Angelis Francesco 
Published: January 2016

AbstractSo wie man in einem U‐Boot Objekte oberhalb der Wasseroberfläche mit einem Periskop erfassen kann, so kann man die Elektrospray‐Massenspektrometrie (ESI‐MS) als eine Art umgekehrtes Periskop auffassen, um an der Gas/Flüssig‐Schnittstelle gelöste Verbindungen auf ihre chemische Zusammensetzung hin zu analysieren. Ziel ist es, Zwischenstufen in chemischen Umsetzungen, die sich anderweitig der Charakterisierung entziehen und für den Ablauf der Reaktion entscheidend sind, zu identifizieren und strukturell zu charakterisieren. Anhand von ausgewählten aktuellen Publikationen werden in diesem Kurzaufsatz die ESI‐MS‐Techniken erläutert, die derzeit zur Erforschung von Zwischenstufen in homogenen chemischen Reaktionen in Lösung eingesetzt werden.
Gold‐katalysierte hochselektive Photoredox‐C(sp2)‐H‐Difluoralkylierung und ‐Perfluoralkylierung von Hydrazonen
Authors: Xie Jin , Zhang Tuo , Chen Fei , Mehrkens Nina , Rominger Frank , Rudolph Matthias , Hashmi A. Stephen K. 
Published: January 2016

AbstractDie ersten erfolgreichen gold‐katalysierten photoredoxselektiven C(sp2)‐H‐Difluoralkylierungen und ‐Perfluoralkylierungen von Hydrazonen mit gut verfügbaren RF‐Br‐Reagentien werden beschrieben. Die resultierenden gem‐difluormethylierten und perfluoralkylierten Hydrazone sind hoch funktionalisierte, vielseitige Moleküle. Eine milde Reduktion der Kupplungsprodukte liefert effizient gem‐difluormethylierte β‐Aminophosphonsäuren und β‐Aminosäure‐Derivate. In mechanistischen Studien wurde eine Difluoroalkylradikal‐Zwischenstufe in einem EPR‐“Spin‐Trapping”‐Experiment detektiert, was auf einen gold‐katalysierten Radikal‐Mechanismus hinweist.
Modulated Binary–Ternary Dual Semiconductor Heterostructures
Authors: Prusty Gyanaranjan , Guria Amit K. , Mondal Indranil , Dutta Anirban , Pal Ujjwal , Pradhan Narayan 
Published: January 2016

AbstractA generic modular synthetic strategy for the fabrication of a series of binary‐ternary group II‐VI and group I‐III‐VI coupled semiconductor nano‐heterostructures is reported. Using Ag2Se nanocrystals first as a catalyst and then as sacrificial seeds, four dual semiconductor heterostructures were designed with similar shapes: CdSe‐AgInSe2, CdSe‐AgGaSe2, ZnSe‐AgInSe2, and ZnSe‐AgGaSe2. Among these, dispersive type‐II heterostructures are further explored for photocatalytic hydrogen evolution from water and these are observed to be superior catalysts than the binary or ternary semi‐conductors. Details of the chemistry of this modular synthesis have been studied and the photophysical processes involved in catalysis are investigated.
Delocalization and Valence Tautomerism in Vanadium Tris(iminosemiquinone) Complexes
Authors: Bendix Jesper , Clark Kensha Marie 
Published: January 2016

AbstractTo survey the noninnocence of bis(arylimino) acenaphthene (BIAN) ligands (L) in complexes with early metals, the homoleptic vanadium complex, [V(L)3] (1), and its monocation, [V(L)3]PF6 (2), were synthesized. These complexes were found to have a very rich electronic behavior, whereby 1 displays strong electronic delocalization and 2 can be observed in unprecedented valence tautomeric forms. The oxidation states of the metal and ligand components in these complexes were assigned by using spectroscopic, crystallographic, and magnetic analyses. Complex 1 was identified as [VIV(Lred)(L.)2] (Lred=N,N′‐bis(3,5‐dimethylphenylamido)acenaphthylene; L.=N,N′‐bis(3,5‐dimethylphenylimino)acenaphthenesemiquinonate). Complex 2 was determined to be [VV(Lred)(L.)2]+ at T<150 K and [VIV(L.)3]+ at T>150 K. Cyclic voltammetry experiments reveal six quasi‐reversible processes, thus indicating the potential of this metal–ligand combination in catalysis or materials applications.
Isolierung und vielseitige Derivatisierung eines ungesättigten anionischen Siliciumclusters (Silicoid)
Authors: Willmes Philipp , Leszczyńska Kinga , Heider Yannic , Abersfelder Kai , Zimmer Michael , Huch Volker , Scheschkewitz David 
Published: January 2016

AbstractDie charakteristischen Merkmale von Silicium‐Oberflächenmaterialen werden in den verwandten, partiell substituierten – und folglich ungesättigten – neutralen Siliciumclustern (den Silicoiden) widergespiegelt. Der Einbau von Silicoiden in ausgedehntere Systeme ist aufgrund ihrer elektronischen Eigenschaften vielversprechend. Weitere Entwicklungen auf diesem Gebiet sind bisher allerdings durch das Fehlen funktionalisierter Silicoidderivate limitiert. Wir berichten hier von der Isolierung und vollständigen Charakterisierung des Lithiumsalzes eines anionischen R5Si6‐Silicoids und liefern damit zugleich das fehlende Glied zwischen Silicium‐basierten Zintl‐Anionen und silicoiden Clustern. Das hohe Potential dieser Spezies für den effizienten Transfer der intakten, ungesättigten R5Si6‐Einheit wird durch saubere Reaktionen mit repräsentativen Elektrophilen der Gruppen 13, 14 und 15 grundsätzlich demonstriert.
A Bifunctional Photosensitizer for Enhanced Fractional Photodynamic Therapy: Singlet Oxygen Generation in the Presence and Absence of Light
Authors: Turan Ilke Simsek , Yildiz Deniz , Turksoy Abdurrahman , Gunaydin Gurcan , Akkaya Engin U. 
Published: January 2016

AbstractThe photosensitized generation of singlet oxygen within tumor tissues during photodynamic therapy (PDT) is self‐limiting, as the already low oxygen concentrations within tumors is further diminished during the process. In certain applications, to minimize photoinduced hypoxia the light is introduced intermittently (fractional PDT) to allow time for the replenishment of cellular oxygen. This condition extends the time required for effective therapy. Herein, we demonstrated that a photosensitizer with an additional 2‐pyridone module for trapping singlet oxygen would be useful in fractional PDT. Thus, in the light cycle, the endoperoxide of 2‐pyridone is generated along with singlet oxygen. In the dark cycle, the endoperoxide undergoes thermal cycloreversion to produce singlet oxygen, regenerating the 2‐pyridone module. As a result, the photodynamic process can continue in the dark as well as in the light cycles. Cell‐culture studies validated this working principle in vitro.
Organometallic Rhenium Complexes Divert Doxorubicin to the Mitochondria
Authors: Imstepf Sebastian , Pierroz Vanessa , Rubbiani Riccardo , Felber Michael , Fox Thomas , Gasser Gilles , Alberto Roger 
Published: January 2016

AbstractDoxorubicin, a well‐established chemotherapeutic agent, is known to accumulate in the cell nucleus. By using ICP‐MS, we show that the conjugation of two small organometallic rhenium complexes to this structural motif results in a significant redirection of the conjugates from the nucleus to the mitochondria. Despite this relocation, the two bioconjugates display excellent toxicity toward HeLa cells. In addition, we carried out a preliminarily investigation of aspects of cytotoxicity and present evidence that the conjugates disrupt the mitochondrial membrane potential, are strong inhibitors of human Topoisomerase II, and induce apoptosis. Such derivatives may enhance the therapeutic index of the aggressive parent drug and overcome drug resistance by influencing nuclear and mitochondrial homeostasis.
Gold‐Catalyzed Highly Selective Photoredox C(sp2)−H Difluoroalkylation and Perfluoroalkylation of Hydrazones
Authors: Xie Jin , Zhang Tuo , Chen Fei , Mehrkens Nina , Rominger Frank , Rudolph Matthias , Hashmi A. Stephen K. 
Published: January 2016

AbstractThe first gold‐catalyzed photoredox C(sp2)−H difluoroalkylation and perfluoroalkylation of hydrazones with readily available RF−Br reagents is reported. The resulting gem‐difluoromethylated and perfluoroalkylated hydrazones are highly functionalized, versatile molecules. A mild reduction of the coupling products can efficiently produce gem‐difluoromethylated β‐amino phosphonic acids and β‐amino acid derivatives. In mechanistic studies, a difluoroalkyl radical intermediate was detected by an EPR spin‐trapping experiment, indicating that a gold‐catalyzed radical pathway is operating.
A Synthetic Glycopeptide Vaccine for the Induction of a Monoclonal Antibody that Differentiates between Normal and Tumor Mammary Cells and Enables the Diagnosis of Human Pancreatic Cancer
Authors: Palitzsch Björn , Gaidzik Nikola , Stergiou Natascha , Stahn Sonja , Hartmann Sebastian , Gerlitzki Bastian , Teusch Nicole , Flemming Peer , Schmitt Edgar , Kunz Horst 
Published: January 2016

AbstractIn studies within the realm of cancer immunotherapy, the synthesis of exactly specified tumor‐associated glycopeptide antigens is shown to be a key strategy for obtaining a highly selective biological reagent, that is, a monoclonal antibody that completely differentiates between tumor and normal epithelial cells and specifically marks the tumor cells in pancreas tumors. Mucin MUC1, which is overexpressed in many prevalent cancers, was identified as a promising target for this strategy. Tumor‐associated MUC1 differs significantly from that expressed by normal cells, in particular by altered glycosylation. Structurally defined tumor‐associated MUC1 cannot be isolated from tumor cells. We synthesized MUC1–glycopeptide vaccines and analyzed their structure–activity relationships in immunizations; a monoclonal antibody that specifically distinguishes between human normal and tumor epithelial cells was thus generated.
Stereoselective Arene‐Forming Aldol Condensation: Synthesis of Configurationally Stable Oligo‐1,2‐naphthylenes
Authors: Lotter Dominik , Neuburger Markus , Rickhaus Michel , Häussinger Daniel , Sparr Christof 
Published: January 2016

AbstractStructurally well‐defined oligomers are fundamental for the functionality of natural molecular systems and key for the design of synthetic counterparts. Herein, we describe a strategy for the efficient synthesis of individual stereoisomers of 1,2‐naphthylene oligomers by iterative building block additions and consecutive stereoselective arene‐forming aldol condensation reactions. The catalyst‐controlled atropoenantioselective and the substrate‐controlled atropodiastereoselective aldol condensation reaction provide structurally distinct ter‐ and quaternaphthalene stereoisomers, which represent configurationally stable analogues of otherwise stereodynamic, helically shaped ortho‐phenylenes.
Light‐Harvesting Systems Based on Organic Nanocrystals To Mimic Chlorosomes
Authors: Chen Peng‐Zhong , Weng Yu‐Xiang , Niu Li‐Ya , Chen Yu‐Zhe , Wu Li‐Zhu , Tung Chen‐Ho , Yang Qing‐Zheng 
Published: January 2016

AbstractWe report the first highly efficient artificial light‐harvesting systems based on nanocrystals of difluoroboron chromophores to mimic the chlorosomes, one of the most efficient light‐harvesting systems found in green photosynthetic bacteria. Uniform nanocrystals with controlled donor/acceptor ratios were prepared by simple coassembly of the donors and acceptors in water. The light‐harvesting system funneled the excitation energy collected by a thousand donor chromophores to a single acceptor. The well‐defined spatial organization of individual chromophores in the nanocrystals enabled an energy transfer efficiency of 95 %, even at a donor/acceptor ratio as high as 1000:1, and a significant fluorescence of the acceptor was observed up to donor/acceptor ratios of 200 000:1.
Pd Nanocubes@ZIF‐8: Integration of Plasmon‐Driven Photothermal Conversion with a Metal–Organic Framework for Efficient and Selective Catalysis
Authors: Yang Qihao , Xu Qiang , Yu Shu‐Hong , Jiang Hai‐Long 
Published: January 2016

AbstractComposite nanomaterials usually possess synergetic properties resulting from the respective components and can be used for a wide range of applications. In this work, a Pd nanocubes@ZIF‐8 composite material has been rationally fabricated by encapsulation of the Pd nanocubes in ZIF‐8, a common metal–organic framework (MOF). This composite was used for the efficient and selective catalytic hydrogenation of olefins at room temperature under 1 atm H2 and light irradiation, and benefits from plasmonic photothermal effects of the Pd nanocube cores while the ZIF‐8 shell plays multiple roles; it accelerates the reaction by H2 enrichment, acts as a “molecular sieve” for olefins with specific sizes, and stabilizes the Pd cores. Remarkably, the catalytic efficiency of a reaction under 60 mW cm−2 full‐spectrum or 100 mW cm−2 visible‐light irradiation at room temperature turned out to be comparable to that of a process driven by heating at 50 °C. Furthermore, the catalyst remained stable and could be easily recycled. To the best of our knowledge, this work represents the first combination of the photothermal effects of metal nanocrystals with the favorable properties of MOFs for efficient and selective catalysis.
Ruthenium‐Catalyzed C−C Bond Cleavage of 2H‐Azirines: A Formal [3+2+2] Cycloaddition to Fused Azepine Skeletons
Authors: Li Tengfei , Xu Fen , Li Xincheng , Wang Chunxiang , Wan Boshun 
Published: January 2016

Abstract2H‐azirines can serve as three‐atom synthons by C−C bond cleavage, however, it involves a high energy barrier under thermal conditions (>50.0 kcal mol−1). Reported is a ruthenium‐catalyzed [3+2+2] cycloaddition reaction of 2H‐azirines with diynes, thus leading to the formation of fused azepine skeletons. This approach features an unprecedented metal‐catalyzed C−C bond cleavage of 2H‐azirines at room temperature, and the challenging construction of aza‐seven‐membered rings from diynes. The results of this study provide a new reaction pattern for constructing nitrogen‐containing seven‐membered rings and may find applications in the synthesis of other complex heterocycles.