bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seismic imaging of the Sun's far hemisphere and its applications in space weather forecasting
Authors: Lindsey Charles , Braun Douglas 
Published: February 2017

AbstractThe interior of the Sun is filled acoustic waves with periods of about 5 min. These waves, called “p modes,” are understood to be excited by convection in a thin layer beneath the Sun's surface. The p modes cause seismic ripples, which we call “the solar oscillations.” Helioseismic observatories use Doppler observations to map these oscillations, both spatially and temporally. The p modes propagate freely throughout the solar interior, reverberating between the near and far hemispheres. They also interact strongly with active regions at the surfaces of both hemispheres, carrying the signatures of said interactions with them. Computational analysis of the solar oscillations mapped in the Sun's near hemisphere, applying basic principles of wave optics to model the implied p modes propagating through the solar interior, gives us seismic maps of large active regions in the Sun's far hemisphere. These seismic maps are useful for space weather forecasting. For the past decade, NASA's twin STEREO spacecraft have given us full coverage of the Sun's far hemisphere in electromagnetic (EUV) radiation from the far side of Earth's orbit about the Sun. We are now approaching a decade during which the STEREO spacecraft will lose their farside vantage. There will occur significant periods from thence during which electromagnetic coverage of the Sun's far hemisphere will be incomplete or nil. Solar seismology will make it possible to continue our monitor of large active regions in the Sun's far hemisphere for the needs of space weather forecasters during these otherwise blind periods.
The prognostic relevance of serum lactate dehydrogenase and mild bone marrow reticulin fibrosis in essential thrombocythemia
Authors: Mudireddy Mythri , Barraco Daniela , Hanson Curtis A. , Pardanani Animesh , Gangat Naseema , Tefferi Ayalew 
Published: February 2017

AbstractThe 2016 World Health Organization (WHO) diagnostic criteria for myeloproliferative neoplasms (MPN) underscore the prognostically‐relevant distinction between essential thrombocythemia (ET) and prefibrotic primary myelofibrosis (pre‐PMF). In addition, leukocytosis has been identified as an important prognostic marker in otherwise WHO‐defined ET. However, controversy remains regarding the objectivity of morphologic criteria in distinguishing ET from pre‐PMF and the precise prognostic cutoff values for leukocytosis. Serum lactate dehydrogenase (LDH) level might be a biologically more accurate measure of leukocyte turnover and a more sensitive marker of pre‐PMF, in otherwise WHO‐defined ET. In the current study of 183 consecutive patients with WHO‐defined ET, the presence of grade 1 bone marrow (BM) fibrosis did not affect presenting clinical or laboratory features; in contrast, increased serum LDH at diagnosis was associated with leukocytosis (p = .002), thrombocytosis (p < .001), palpable splenomegaly (p = .03) and higher international prognostic score (IPSET) (p = .002); serum LDH did not correlate with BM fibrosis, JAK2/CALR/MPL or TET2/ASXL1 mutations. In univariate analysis, risk factors for survival included age ≥60 years (p = .002; HR 10.2, 95% CI 2.3‐44.6), male sex (p = .02; HR 3.2, 95% CI 1.2‐8.2), leukocyte count ≥15 × 109/L (p = .007; HR 4.7, 95% CI 1.5‐14.6), and increased serum LDH (p = .002; HR 3.7, 95% CI 1.5‐9.1), but not BM fibrosis (p = .17). In multivariable analysis, age, sex and serum LDH remained significant; serum LDH also remained significant, in the context of IPSET (p = .003) and in patients with leukocytosis (p = .003). We conclude that serum LDH level carries an independent prognostic value for survival in ET and might represent a biologically more accurate surrogate for leukocytosis.
One‐Pot Assembly of Amino Acid Bridged Hybrid Macromulticyclic Cages through Multiple Multicomponent Macrocyclizations
Authors: Wessjohann Ludger A. , Kreye Oliver , Rivera Daniel G. 
Published: February 2017

AbstractAn important development in the field of macrocyclization strategies towards molecular cages is described. The approach comprises the utilization of a double Ugi four‐component macrocyclization for the assembly of macromulticycles with up to four different tethers, that is, hybrid cages. The innovation of this method rests on setting up the macromulticycle connectivities not through the tethers but through the bridgeheads, which in this case involve N‐substituted amino acids. Both dilution and metal‐template‐driven macrocyclization conditions were implemented with success, enabling the one‐pot formation of cryptands and cages including steroidal, polyether, heterocyclic, peptidic, and aryl tethers. This method demonstrates substantial complexity‐generating character and is suitable for applications in molecular recognition and catalysis.
Ein stabiles Hexakis(guanidino)benzol: Synthese des stärksten neutralen organischen Vier‐Elektronen‐Donors
Authors: Eberle Benjamin , Kaifer Elisabeth , Himmel Hans‐Jörg 
Published: February 2017

AbstractDie wachsende Nachfrage nach effizienten Batterien hat die Suche nach redoxaktiven organischen Verbindungen mit mehrstufigem Redoxverhalten als Materialien mit großer Ladungskapazität angeregt. Wir berichten hier über die Synthese und Eigenschaften des ersten Hexakis(guanidino)benzol‐Derivats, eines starken neutralen organischen Elektronendonors mit reversiblem mehrstufigem Redoxverhalten und dem niedrigsten bekannten Redoxpotential für die Abgabe von vier Elektronen. Die detaillierte strukturelle und spektroskopische Charakterisierung dreier Redoxzustände (0, +2 und +4) belegt dessen einzigartigen elektronischen Eigenschaften. Trotz ihres Stickstoffreichtums ist die Verbindung thermisch stabil und lässt sich durch Sublimation reinigen.
Self‐Assembly of Iodine in Superfluid Helium Droplets: Halogen Bonds and Nanocrystals
Authors: He Yunteng , Zhang Jie , Lei Lei , Kong Wei 
Published: February 2017

AbstractWe present evidence of halogen bond in iodine clusters formed in superfluid helium droplets based on results from electron diffraction. Iodine crystals are known to form layered structures with intralayer halogen bonds, with interatomic distances shorter than the sum of the van der Waals radii of the two neighboring atoms. The diffraction profile of dimer dominated clusters embedded in helium droplets reveals an interatomic distance of 3.65 Å, much closer to the value of 3.5 Å in iodine crystals than to the van der Waals distance of 4.3 Å. The profile from larger iodine clusters deviates from a single layer structure; instead, a bi‐layer structure qualitatively fits the experimental data. This work highlights the possibility of small halogen bonded iodine clusters, albeit in a perhaps limited environment of superfluid helium droplets. The role of superfluid helium in guiding the trapped molecules into local potential minima awaits further investigation.
Mehrkomponenten‐Oxyalkylierung von Styrolen durch Wasserstoffbrücken‐unterstützten photoinduzierten Elektronentransfer
Authors: Tlahuext‐Aca Adrian , Garza‐Sanchez R. Aleyda , Glorius Frank 
Published: February 2017

AbstractEine Strategie zur Aktivierung von N‐(Acyloxy)phthalimiden für den photoinduzierten Elektronentransfer durch die Bildung von Wasserstoffbrücken wird vorgestellt. Dieser Aktivierungsmodus führt effektiv zu C(sp3)‐zentrierten Radikalen nach Decarboxylierung von stabilen und leicht zugänglichen Substraten. Darüber hinaus wurde gezeigt, dass die gebildeten Alkylradikale in einem neuartigen redoxneutralen Protokoll zur Bildung von C(sp3)‐C(sp3)‐Bindungen zwischen Styrol‐Einheiten eingesetzt werden können, was einen einfachen Zugang zu komplexen Alkohol‐ und Ethergerüsten ermöglicht.
Multicomponent Oxyalkylation of Styrenes Enabled by Hydrogen‐Bond‐Assisted Photoinduced Electron Transfer
Authors: Tlahuext‐Aca Adrian , Garza‐Sanchez R. Aleyda , Glorius Frank 
Published: February 2017

AbstractHerein, we disclose a strategy for the activation of N‐(acyloxy)phthalimides towards photoinduced electron transfer through hydrogen bonding. This activation mode enables efficient access to C(sp3)‐centered radicals upon decarboxylation from bench‐stable and readily available substrates. Moreover, we demonstrate that the formed alkyl radicals can be successfully employed in a novel redox‐neutral method for constructing sp3−sp3 bonds across styrene moieties that gives straightforward access to complex alcohol and ether scaffolds.
Enhancing the stability of UV‐curable thiol/vinyl carbonate resins
Authors: Edler Matthias , Mostegel Florian H. , Roth Meinhart , Oesterreicher Andreas , Kappaun Stefan , Griesser Thomas 
Published: February 2017

ABSTRACTIn this study, the effect of various stabilizer systems on low‐cytotoxic thiol/vinyl carbonate formulations was evaluated with the aim to inhibit premature dark polymerization reactions. The addition of hydroxybenzene‐based radical scavengers such as pyrogallol (PyG), hydroquinone monomethyl ether (MEHQ), or butylated hydroxytoluene (BHT) resulted in a significantly decelerated increase in viscosity compared to formulations without stabilizers during a defined storage period at 50 °C. The usage of bicomponent stabilization systems in appropriate concentrations further reduced the viscosity increase for nonpigmented formulations. The most effective heterosynergistic stabilization system based on PyG and diisoctyl phosphonic acid (9 mM/90 mM) exerts only a minor influence on the polymerization performance, which was shown by photo‐DSC measurements. The herein presented stabilization of vinyl carbonate/thiol resins exhibits a significant contribution to bringing these low‐toxic building blocks into industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44934.
Reachable Set Estimation for Discrete‐Time Singular Systems
Authors: Li Jiangrong , Feng Zhiguang , Zhang Changzhu 
Published: February 2017

AbstractThis paper is concerned with the problem of reachable set estimation for discrete‐time singular systems with bounded input disturbances. Based on the Lyapunov method, a new sufficient condition is established in terms of linear matrix inequality (LMI) to guarantee that the reachable set of discrete‐time singular system is bounded by the intersection of ellipsoids. Then the result is extended to the problem for discrete‐time singular systems with time‐varying delay by utilizing the delay‐dependent approach and free weighting matrices. Two numerical examples are provided to demonstrate the effectiveness of the obtained results proposed in this paper.
Tunable luminescence and energy transfer in Ca3SiO4Cl2:Ce3+,Li+,Mn2+,Eu2+ phosphors
Authors: Li Xiangqi , Xie Xiuzhen , Wei Haiting , Zhong Minzhen 
Published: February 2017

AbstractA series of color‐tunable Ca3–2x‐y‐zSiO4Cl2 (CSC):xCe3+,xLi+,yMn2+,zEu2+ phosphors with low temperature phase structure was synthesized via the sol–gel method. An energy transfer process from Ce3+ to Mn2+ in CSC:0.01Ce3+,0.01Li+,yMn2+ (y = 0.03–0.09) and the mechanism was verified to be an electric dipole–dipole interaction. The Ce3+ and Mn2+ emission intensities were greatly enhanced by co‐doping Eu2+ ions into CSC:0.01Ce3+,0.01Li+,0.07Mn2+ phosphors due to competitive energy transfers from Eu2+/Ce3+ to Mn2+, and Ce3+ to Eu2+. Under 332 nm excitation, CSC:0.01Ce3+,0.01Li+,0.07Mn2+,zEu2+ (z = 0.0005–0.002) exhibited tunable emission colors from green to white with coexisting orange, green and violet‐blue emissions. These phosphors could have potential application in white light‐emitting diodes.
Citizen Science
Authors: Zizka Georg 
Published: February 2017

ZusammenfassungCitizen Science ist charakterisiert durch ehrenamtliche wissenschaftliche Arbeit von Personen, die nicht in diesem Bereich beruflich tätig sind und kann bezüglich Fachrichtung, Ausbildung, Vorkenntnissen und Zeiteinsatz der Akteure sehr unterschiedlich sein. Gerade in Bereichen, die heute oft von der Berufswissenschaft vernachlässigt werden, z. B. der regionalen Forschung, spielt diese Form der Citizen Science („Citizen Science proper”) eine wichtige Rolle.In den letzten Jahren hat sich eine andere, jüngere Form der Bürgerwissenschaft stark entwickelt, bei der eine größere Zahl von Personen an der Erhebung von wissenschaftlichen Daten mitwirkt („Citizen Science light”). Internet, Smartphones und Georeferenzierung über GPS sind wichtige Werkzeuge für die Dokumentation und Weiterleitung der Daten. Neben dem wissenschaftlichen Ertrag spielen die Erhöhung der gesellschaftlichen Relevanz durch Teilnahme und Information der Bürger sowie die Mobilisierung, z. B. für den Naturschutz, eine sehr wichtige Rolle. Die aktuell große Resonanz und Beteiligung im Bereich „Citizen Science” ist ein wichtiger Fortschritt, der dazu beiträgt, Wissenschaft stärker in der Gesellschaft zu verankern und ihre Ergebnisse zu kommunizieren.
Renal damage following Alloxan‐induced diabetes is associated with generation of reactive oxygen species, alterations of p53, TGF‐β1, and extracellular matrix metalloproteinases in rats
Authors: Abdel Aziz Mohamed A. , Badary Dalia M. , Hussein Mahmoud Rezk Abdelwahed 
Published: February 2017

AbstractRenal damage is a common problem in diabetes. Alloxan, a potent hyperglycemic and diabetogenic molecule, can induce diabetes through oxidative stress‐related mechanisms. Here, we hypothesize that “Alloxan‐induced renal damage is associated with alterations of p53, TGF‐β1, and extracellular matrix metalloproteinases.” To test our hypothesis, we established an animal model (male abino rats) and induced diabetes by intraperitoneal injection of Alloxan monohydrate. Rats with fasting blood glucose level ≥ 200 mg/dL were considered diabetic and were sacrificed after 14, 28, and 42 day intervals. Tissue levels of malondialdehyde and glutathione levels (markers of oxidative stress), and serum MMP‐1 were measured. The expression patterns of p53, TGF‐β1were evaluated using Western blot and immunohistochemical methods. TIMP‐1 expression pattern was determined using RT‐PCR and immunohistochemical methods. Alloxan treatment induced histological features of renal damage (inflammation and fibrosis) and was associated with deterioration of the renal functions (elevated blood urea nitrogen and creatinin levels), hyperglycemia, and oxidative stresss (increased malondialdehyde and decreased glutathione levels). There was over‐expression of the TGF‐β1 protein (profibrogenic protein), p53 (proapoptotic protein), and alterations of extracellular matrix proteins (low level of serum MMP‐1 and over‐expression of TIMP‐1). Alterations of TGF‐β, p53, and extracellular matrix metalloproteinases contribute to the pathogenesis of Alloxan‐induced renal damage.
Good to great: TAVR tackles stroke risk
Authors: Pelberg Justin , Gray William A. 
Published: February 2017

Key Points

In this small feasibility trial of a next‐generation device, the TriGuardHDH embolic protection device (EPD) appears to be safe and feasible during use in the majority of the TAVR subjects studied.
The question as to the use of EPD during TAVR, while intuitively appealing, is not further elucidated by the results of this small, uncontrolled study.
Future research on this (and other) device(s) would be expected to include, at a minimum, a randomized arm, more standardized imaging, and neurological assessment (including longer‐term) protocols, and less variability in valve types used.
Label‐Free Electrochemiluminescence Aptasensor for Highly Sensitive Detection of Acetylcholinesterase Based on Au‐Nanoparticle‐Functionalized g‐C3N4 Nanohybrid
Authors: Liu Qiao , Peng Yu‐Jiao , Xu Jin‐Chun , Ma Cheng , Li Lingling , Mao Chang‐Jie , Zhu Jun‐Jie 
Published: February 2017

AbstractA feasible label‐free electrochemiluminescence (ECL) aptasensor that uses an Au‐nanoparticle‐functionalized g‐C3N4 nanohybrid (Au‐g‐C3N4 NH) as the luminophore was constructed for highly sensitive acetylcholinesterase (AChE) detection. The sensor was fabricated by successively modifying a glassy carbon electrode with Au‐g‐C3N4 NH and thiol‐modified AChE‐specific aptamers. In the presence of AChE, the ECL signal decreased significantly, because AChE could hydrolyze the substrate acetylthiocholine to generate acetic acid, which could react with the co‐reactant triethylamine (Et3N), leading to evident consumption of the co‐reactant. The ECL response of the aptasensor was linearly proportional to the concentration of AChE ranging from 0.1 pg/mL to 10 ng/mL, with a detection limit of 42.3 fg/mL (S/N=3). This novel ECL sensing strategy demonstrated a highly sensitive and selective method for AChE detection and was expected to possess potential applications in clinical diagnosis and biomedical technology.
Ge@CNFs Anchored on 3D Graphene Foam for Binder‐Free and High‐Efficiency Anodes in Li–Ion Batteries
Authors: Peng Chang Jian , Wang Lei , Li Qing Wei , Li Yuan Yuan , Huo Kaifu , Chu Paul K. 
Published: February 2017

AbstractA spider‐like Ge@CNFs/3D graphene nanocomposite is prepared and used as a binder‐free, large‐capacity, high‐rate, and long‐life anode in lithium‐ion batteries (LIBs). The carbon nanofibers (CNFs) are radially grown on the Ge nanoparticles and then attached onto the 3D graphene foam to form Ge@CNFs/3D graphene. The CNFs buffer the internal stress induced by the volume change, alleviate Ge NP detachment or break down, and prevent aggregation of Ge during cycling. Moreover, the integrated structure of the 3D graphene facilitates fast electron transport and rapid diffusion of Li ions. The obtained spider‐like Ge@CNFs/3D graphene composite shows a capacity of 594 mA h g−1 (based on total mass of the electrode) after 1200 cycles at a current density of 0.8 A g−1. Furthermore, at 12.8 A g−1, the Ge@CNFs/3D graphene nanocomposite delivers a reversible capacity of 474 mA h g−1, corresponding to 74% capacity retention at 0.32 A g−1, rendering it promising for application in high‐performance LIBs.
Synthesis and Reduction of Uranium(V) Imido Complexes with Redox‐Active Substituents
Authors: Mullane Kimberly C. , Carroll Patrick J. , Schelter Eric J. 
Published: February 2017

AbstractOrganic azides that contain naphthyl functional groups were used to prepare uranium(V) imido complexes UV[=NC(2‐naph)Ph2][N(SiMe3)2]3 (2), UV[=NC(2‐naph)3][N(SiMe3)2]3 (3), and UV[=N(2‐naph)][N(SiMe3)2]3 (4), and their properties were compared with UV[=NCPh3][N(SiMe3)2]3 (1). The electronic structures of these compounds were investigated by solution electrochemistry studies, which revealed accessible UV/VI, UIV/V, and naphthalene0/naphthalene−1 couples. The uranium(V) naphthylimido complexes were reduced by potassium graphite to yield their uranium(IV) congeners K[UIV[=NC(2‐naph)Ph2][N(SiMe3)2]3] (2‐K), K[UIV[=NC(2‐naph)3][N(SiMe3)2]3] (3‐K), and K[UIV[=N(2‐naph)][N(SiMe3)2]3] (4‐K). The electronic structure of the dianionic compounds were investigated by DFT calculations, and this revealed that the second reduction was ligand‐based, which opens the possibility of accomplishing multi‐electron redox chemistry by using a tailored multiply‐bonded ligand.
Controlled Synthesis of Octahedral Platinum‐Based Mesocrystals by Oriented Aggregation
Authors: Zhong Ping , Liu Hongpo , Zhang Jie , Yin Yadong , Gao Chuanbo 
Published: February 2017

AbstractDesigned synthesis of noble metal mesocrystals is of great significance for a variety of applications. Here, the synthesis of octahedral Pt‐Ag alloy mesocrystals with precisely controlled morphology, size, and exposing facets, formed by oriented aggregation of their crystallites, is reported. The critical role of bromide was revealed in regulating the overall octahedral morphology of the Pt–Ag mesocrystals, by bridging the interactions between the capping agent and the Ag‐modified Pt crystallites. The size of the mesocrystals was precisely controlled in a broad range by tuning the number of the seeds, all retaining their octahedral morphology. Based on this understanding, octahedral Pt–Ag mesocrystals exposing {1 1 1} facets have been obtained in a highly controllable and reproducible manner. This material showed excellent electrocatalytic activity and stability in oxygen reduction reactions (ORR). It is hoped that the current synthesis provides new insights that pave the way to diverse faceted nanocrystals/mesocrystals for high‐performance catalytic and many other applications.
Structural Studies of Nicotinoids: Cotinine versus Nicotine
Authors: Uriarte Iciar , Pérez Cristóbal , Caballero‐Mancebo Elena , Basterretxea Francisco J. , Lesarri Alberto , Fernández José A. , Cocinero Emilio J. 
Published: February 2017

AbstractNicotinoids are agonists of the acetylcholine receptor (nAChR) and play important biochemical and pharmacological roles. Herein, we report on the structure and conformation of cotinine, and compare its molecular properties with the nicotine prototype, from which it only differs in the addition of a carbonyl group. This investigation included a theoretical survey of the effects of rotamerization of the pyridine moiety, the puckering of the pyrrolidinone ring and the internal rotation of the methyl group. The experimental work examined the rotational spectrum of the molecule in a supersonic expansion, using both broadband chirped‐pulse excitation techniques and cavity microwave spectrometers. Two conformers were observed for cotinine, and the fine and hyperfine structures arising from the two quadrupolar 14N nuclei and the methyl internal rotor were fully analyzed. The two observed conformers share the same twisted conformation of the five‐membered ring, but differ in a roughly 180° rotamerization around the C−C bond connecting the two rings. The energy barriers for the internal rotation of the methyl group in cotinine (4.55(4) and 4.64(3) kJ mol−1, respectively) are much lower than in nicotine (estimated in 16.5 kJ mol−1). The combination of different intramolecular electronic effects, hydrogen bonding and possible binding differences to receptor molecules arising from the carbonyl group could explain the lower affinity of cotinine for nAChRs.
Highly Stable Sr‐Free Cobaltite‐Based Perovskite Cathodes Directly Assembled on a Barrier‐Layer‐Free Y2O3‐ZrO2 Electrolyte of Solid Oxide Fuel Cells
Authors: Ai Na , Li Na , Rickard William D. A. , Cheng Yi , Chen Kongfa , Jiang San Ping 
Published: February 2017

AbstractDirect assembly is a newly developed technique in which a cobaltite‐based perovskite (CBP) cathode can be directly applied to a barrier‐layer‐free Y2O3‐ZrO2 (YSZ) electrolyte with no high‐temperature pre‐sintering steps. Solid oxide fuel cells (SOFCs) based on directly assembled CBPs such as La0.6Sr0.4Co0.2Fe0.8O3−δ show high performance initially but degrade rapidly under SOFC operation conditions at 750 °C owing to Sr segregation and accumulation at the electrode/electrolyte interface. Herein, the performance and interface of Sr‐free CBPs such as LaCoO3−δ (LC) and Sm0.95CoO3−δ (SmC) and their composite cathodes directly assembled on YSZ electrolyte was studied systematically. The LC electrode underwent performance degradation, most likely owing to cation demixing and accumulation of La on the YSZ electrolyte under polarization at 500 mA cm−2 and 750 °C. However, the performance and stability of LC electrodes could be substantially enhanced by the formation of LC‐gadolinium‐doped ceria (GDC) composite cathodes. Replacement of La by Sm increased the cell stability, and doping of 5 % Pd to form Sm0.95Co0.95Pd0.05O3−δ (SmCPd) significantly improved the electrode activity. An anode‐supported YSZ‐electrolyte cell with a directly assembled SmCPd‐GDC composite electrode exhibited a peak power density of 1.4 W cm−2 at 750 °C, and an excellent stability at 750 °C for over 240 h. The higher stability of SmC as compared to that of LC is most likely a result of the lower reactivity of SmC with YSZ. This study demonstrates the new opportunities in the design and development of intermediate‐temperature SOFCs based on the directly assembled high‐performance and durable Sr‐free CBP cathodes.