bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mw dependence of the preseismic ionospheric electron enhancements
Authors: Heki K. , Enomoto Y. 
Published: July 2015

AbstractIonospheric electron enhancement was reported to have occurred ~40 min before the 2011 Tohoku‐oki (Mw9.0) earthquake, Japan, by observing total electron content (TEC) with Global Navigation Satellite Systems receivers. Their reality has been repeatedly questioned due mainly to the ambiguity in the derivation of the reference TEC curves from which anomalies are defined. Here we propose a numerical approach, based on Akaike's information criterion, to detect positive breaks (sudden increase of TEC rate) in the vertical TEC time series without using reference curves. We demonstrate that such breaks are detected 25–80 min before the eight recent large earthquakes with moment magnitudes (Mw) of 8.2–9.2. The amounts of precursory rate changes were found to depend upon background TEC as well as Mw. The precursor times also showed Mw dependence, and the precursors of intraplate earthquakes tend to start earlier than interplate earthquakes. We also performed the same analyses during periods without earthquakes to evaluate the usefulness of TEC observations for short‐term earthquake prediction.
Comparison of co‐located independent ground‐based middle atmospheric wind and temperature measurements with numerical weather prediction models
Authors: Le Pichon A. , Assink J. D. , Heinrich P. , Blanc E. , Charlton‐Perez A. , Lee C. F. , Keckhut P. , Hauchecorne A. , Rüfenacht R. , Kämpfer N. , Drob D. P. , Smets P. S. M. , Evers L. G. , Ceranna L. , Pilger C. , Ross O. , Claud C. 
Published: July 2015

AbstractHigh‐resolution, ground‐based and independent observations including co‐located wind radiometer, lidar stations, and infrasound instruments are used to evaluate the accuracy of general circulation models and data‐constrained assimilation systems in the middle atmosphere at northern hemisphere midlatitudes. Systematic comparisons between observations, the European Centre for Medium‐Range Weather Forecasts (ECMWF) operational analyses including the recent Integrated Forecast System cycles 38r1 and 38r2, the NASA's Modern‐Era Retrospective Analysis for Research and Applications (MERRA) reanalyses, and the free‐running climate Max Planck Institute–Earth System Model–Low Resolution (MPI‐ESM‐LR) are carried out in both temporal and spectral domains. We find that ECMWF and MERRA are broadly consistent with lidar and wind radiometer measurements up to ~40 km. For both temperature and horizontal wind components, deviations increase with altitude as the assimilated observations become sparser. Between 40 and 60 km altitude, the standard deviation of the mean difference exceeds 5 K for the temperature and 20 m/s for the zonal wind. The largest deviations are observed in winter when the variability from large‐scale planetary waves dominates. Between lidar data and MPI‐ESM‐LR, there is an overall agreement in spectral amplitude down to 15–20 days. At shorter time scales, the variability is lacking in the model by ~10 dB. Infrasound observations indicate a general good agreement with ECWMF wind and temperature products. As such, this study demonstrates the potential of the infrastructure of the Atmospheric Dynamics Research Infrastructure in Europe project that integrates various measurements and provides a quantitative understanding of stratosphere‐troposphere dynamical coupling for numerical weather prediction applications.
Measurements of the complex refractive index of volcanic ash at 450, 546.7, and 650 nm
Authors: Ball J. G. C. , Reed B. E. , Grainger R. G. , Peters D. M. , Mather T. A. , Pyle D. M. 
Published: July 2015

AbstractThe detection and quantification of volcanic ash is extremely important to the aviation industry, civil defense organizations, and those in peril from volcanic ashfall. To exploit the remote sensing techniques that are used to monitor a volcanic cloud and return information on its properties, the effective complex refractive index of the volcanic ash is required. This paper presents the complex refractive index determined in the laboratory at 450.0 nm, 546.7 nm, and 650.0 nm for volcanic ash samples from eruptions of Aso (Japan), Grímsvötn (Iceland), Chaitén (Chile), Etna (Italy), Eyjafjallajökull (Iceland), Tongariro (New Zealand), Askja (Iceland), Nisyros (Greece), Okmok (Alaska), Augustine (Alaska), and Spurr (Alaska). The Becke line method was used to measure the real part of the refractive index with an accuracy of 0.01. The values measured differed between eruptions and were in the range 1.51–1.63 at 450.0 nm, 1.50–1.61 at 546.7 nm, and 1.50–1.59 at 650.0 nm. A novel method is introduced to derive the imaginary part of the refractive index from the attenuation of light by ash. The method has a precision in the range 10−3–10−4. The values for the ash imaginary refractive index ranged 0.22–1.70 × 10−3 at 450.0 nm, 0.16–1.93 × 10−3 at 546.7 nm, and 0.15–2.08 × 10−3 at 650.0 nm. The accuracy of Becke and attenuation methods was assessed by measuring the complex refractive index of Hoya neutral density glass and found to have an accuracy of <0.01 and <2 × 10−5 for the real and imaginary parts of the refractive index, respectively.
Getting the Picture: Effects of Sketch Plans and Photographs on Children's, Adolescents' and Adults' Eyewitness Recall
Authors: Jack Fiona , Martyn Elise , Zajac Rachel 
Published: July 2015

SummaryWe compared the effects of three types of visual aid on free recall across three age groups in an eyewitness paradigm. Child, adolescent and adult participants (N = 144) viewed a short film depicting a non‐violent crime and, following a brief delay, gave a free‐recall account. Participants then described the event once again, with the aid of their own sketch plan, a provided sketch plan or photograph, or with no visual aid. Interviews were transcribed verbatim and coded for the type and accuracy of information reported. Across all age groups, relative to the control condition, all three visual aids increased the amount of new information reported during the second free‐recall account and helped participants to maintain accuracy. All three visual aids therefore had a positive effect on participants' performance; in a forensic setting, however, witnesses' own sketch plans are likely to be the safest, most easily applied and most time effective.Copyright © 2015 John Wiley & Sons, Ltd.
Assessment of Sacroiliitis at Diagnosis of Juvenile Spondyloarthritis by Radiography, Magnetic Resonance Imaging, and Clinical Examination
Authors: Weiss Pamela F. , Xiao Rui , Biko David M. , Chauvin Nancy A. 
Published: July 2015

ObjectiveTo evaluate the prevalence of sacroiliitis at diagnosis of juvenile spondyloarthritis (SpA) and the accuracy of physical examination and back pain to detect sacroiliitis, using imaging as the reference standard.MethodsWe performed a prospective cross‐sectional study of 40 children with newly diagnosed juvenile SpA and 14 healthy controls. Subjects were assessed using physical examination, anteroposterior pelvic radiograph, and pelvic magnetic resonance imaging (MRI). Differences in clinical features between those children with and without sacroiliitis were assessed by Fisher's exact test for categorical variables and Wilcoxon's rank sum test for continuous variables. Accuracy of physical examination and back pain for detection of sacroiliitis was determined using MRI as the reference standard. Predicted probability of sacroiliitis was determined using exact multivariate logistic regression.ResultsEight children (20%) with juvenile SpA had active sacroiliitis. Of those subjects with active changes on MRI, 7 of 8 (88%) also had evidence of erosions or sclerosis. Five children (13%) with juvenile SpA and 1 control (7%) had nonperiarticular bone marrow edema. Of the subjects with active sacroiliitis, only 3 (38%) reported a history of back pain or tenderness on palpation of the sacroiliac joints. The positive and negative predictive values of clinical examination features and back pain for detection of sacroiliitis were low. The estimated probability of having sacroiliitis was 0.84 (95% confidence interval 0.40–1.00) in HLA–B27–positive patients with an elevated C‐reactive protein (CRP) level.ConclusionActive sacroiliitis by MRI is common at diagnosis in juvenile SpA and is frequently asymptomatic. Children who are HLA–B27–positive and have elevated CRP levels have the highest probability of sacroiliitis.
Synthesis of Heterocycle‐fused Pyridine N‐Oxides from Oximes and Diazo Compounds via RhIII‐Catalyzed CH Activation and Annulation
Authors: Sun Peng , Wu Youzhi , Yang Tie , Wu Xiaoming , Xu Jinyi , Lin Aijun , Yao Hequan 
Published: July 2015

AbstractA RhIII‐catalyzed tandem CH activation and CN bond formation reaction between oximes and diazo compounds for the synthesis of heterocycle‐fused pyridine N‐oxides has been developed. The reaction exhibits good functional group tolerance and regioselectivity. After simple transformation, the 1‐substituted, 1,3‐disubstituted, 1,4‐disubstituted and 1,3,4‐trisubstituted heterocycle‐fused pyridines were all obtained in high efficiency. Moreover, this strategy has also been expanded to the synthesis of a key intermediate for the construction of one potential anti‐HIV agent.magnified image
Heat and hydration status: Predictors of repeated measures of urine specific gravity among Tsimane’ adults in the Bolivian Amazon
Authors: Rosinger Asher 
Published: July 2015

ABSTRACTObjectiveHydration status is critical to physiological and cognitive health, yet it is unclear how populations living in hot‐humid environments experiencing lifestyle transitions manage this underexplored facet of heat adaptation. This study assesses the predictors of repeated measures of hydration status for adults from two villages (close and distant from a market town) in the Bolivian Amazon.Materials and MethodsInterviews and focal follows were conducted with 36 Tsimane’ (50% male). Urine samples, temperature, activity levels, and anthropometrics were measured pre‐interview and post‐follow and yielded a small panel (72 observations). Urine samples were analyzed for urine specific gravity (USG), a biomarker of hydration, with a refractometer.ResultsThe mean USG was 1.020 g/ml (SD ± 0.008) with men (1.022 ± 0.008) slightly more dehydrated than women (1.018 ± 0.007). Using 1.020 as the criteria for clinical dehydration, 42% of the participants were dehydrated at both intervals and 21% were extremely dehydrated. Controlling for activity level, village membership, and covariates in random‐effects linear regression models, each degree centigrade increase was associated with a USG increase of 0.0008 g/ml (P = 0.000). Adults from the village closer to the market town had significantly higher USG (B = 0.0041; P = 0.04) than those in the distant village. Dehydration was predicted to occur at 29°C, just above the thermoneutral range, and extreme dehydration at 37°C.DiscussionThese findings suggest that hotter temperatures coupled with lifestyle transitions may create conditions that increase vulnerability to dehydration among rural populations through landscape modifications and diet changes. Am J Phys Anthropol 158:696–707, 2015. © 2015 Wiley Periodicals, Inc.
Redoxaktive NOx‐Liganden in palladiumvermittelten Prozessen
Authors: J. S. Fairlamb Ian 
Published: July 2015

AbstractDieser Kurzaufsatz fasst jüngste Arbeiten über redoxaktive (“non‐innocent”) NOx‐Liganden (x=1, 2 oder 3) in ausgewählten Pd‐vermittelten Prozessen, beispielsweise Alken‐ und aromatischen Oxidationen, zusammen. Im Mittelpunkt stehen mechanistische Studien, sowie Betrachtungen zu den Parallelen zwischen neueren Umsetzungen, wie C‐H‐Bindungsaktivierungen und der Wacker‐Oxidation, und früheren Arbeiten zur Funktionalisierung von Aromaten und Alkenen mit PdII‐Salzen.
Biomimetische Selbstheilung
Authors: Diesendruck Charles E. , Sottos Nancy R. , Moore Jeffrey S. , White Scott R. 
Published: July 2015

AbstractSelbstheilung ist ein natürlicher Vorgang, der allen lebenden Organismen zu eigen ist und eine höhere Lebensspanne sowie die Fähigkeit zur Anpassung an Umgebungsveränderungen mit sich bringt. Inspiriert von dieser evolutionär entwickelten Funktionalität haben Wissenschaftler und Ingenieure synthetische Materialien mit Selbstheilungsvermögen erschaffen. In Anlehnung an mechanisch ausgelöste chemische Vorgänge und die Speicherung und Abgabe flüssiger Reagentien in der Natur wurden neue Materialien mit höherer Lebensspanne entwickelt, die nach Beschädigung ihre mechanische Integrität sowie zusätzliche Funktionen regenerieren können. Dieser Aufsatz beschreibt die Grundlagen dieses aktuellen Gebiets an der Schnittstelle zwischen Chemie, Physik, Material‐ und Ingenieurwissenschaften.
Einkristalline Halbleiter mit kleinen Bandlücken für die solare Wasserspaltung
Authors: Wang Tuo , Gong Jinlong 
Published: July 2015

AbstractDie Wasserspaltung mittels Sonnenenergie bietet einen sauberen und erneuerbaren Ansatz für die Produktion von Wasserstoff. Einkristalline Halbleiter mit kleinen Bandlücken und geringer Ladungsträgerrekombination, wie Si und InP, erweisen sich als sehr gut geeignet, die Halbreaktionen der Wasserspaltung – die Wasserstoff‐ (HER) und Sauerstoffentwicklung (OER) – unter Einwirkung von sichtbarem Licht zu fördern. Durch die Verwendung dieser Halbleiter als Photoelektroden konnte in jüngster Zeit eine Reihe von Problemen im Zusammenhang mit Photokorrosion, langsamen Reaktionskinetiken, niedrigen Photospannungen und ungünstigen planaren Substratoberflächen gelöst werden. Dieser Kurzaufsatz fasst den aktuellen Stand der Forschungen zusammen, mit Schwerpunkt auf Oberflächenmodifizierungsstrategien, wie z. B. Oberflächenschützung, Beladung mit Kokatalysatoren, Abstimmung der Oberflächenenergetiken und Oberflächentexturierung.
Selective Rhodium‐Catalyzed Reduction of Tertiary Amides in Amino Acid Esters and Peptides
Authors: Das Shoubhik , Li Yuehui , Bornschein Christoph , Pisiewicz Sabine , Kiersch Konstanze , Michalik Dirk , Gallou Fabrice , Junge Kathrin , Beller Matthias 
Published: July 2015

AbstractEfficient reduction of the tertiary amide bond in amino acid derivatives and peptides is described. Functional group selectivity has been achieved by applying a commercially available rhodium precursor and bis(diphenylphosphino)propane (dppp) ligand together with phenyl silane as a reductant. This methodology allows for specific reductive derivatization of biologically interesting peptides and offers straightforward access to a variety of novel peptide derivatives for chemical biology studies and potential pharmaceutical applications. The catalytic system tolerates a variety of functional groups including secondary amides, ester, nitrile, thiomethyl, and hydroxy groups. This convenient hydrosilylation reaction proceeds at ambient conditions and is operationally safe because no air‐sensitive reagents or highly reactive metal hydrides are needed.
Single‐Molecule Visualization of the Activity of a Zn2+‐Dependent DNAzyme
Authors: Endo Masayuki , Takeuchi Yosuke , Suzuki Yuki , Emura Tomoko , Hidaka Kumi , Wang Fuan , Willner Itamar , Sugiyama Hiroshi 
Published: July 2015

AbstractWe demonstrate the single‐molecule imaging of the catalytic reaction of a Zn2+‐dependent DNAzyme in a DNA origami nanostructure. The single‐molecule catalytic activity of the DNAzyme was examined in the designed nanostructure, a DNA frame. The DNAzyme and a substrate strand attached to two supported dsDNA molecules were assembled in the DNA frame in two different configurations. The reaction was monitored by observing the configurational changes of the incorporated DNA strands in the DNA frame. This configurational changes were clearly observed in accordance with the progress of the reaction. The separation processes of the dsDNA molecules, as induced by the cleavage by the DNAzyme, were directly visualized by high‐speed atomic force microscopy (AFM). This nanostructure‐based AFM imaging technique is suitable for the monitoring of various chemical and biochemical catalytic reactions at the single‐molecule level.
Stereoselective Synthesis of α‐3‐Deoxy‐D‐manno‐oct‐2‐ulosonic Acid (α‐Kdo) Glycosides Using 5,7‐O‐Di‐tert‐butylsilylene‐Protected Kdo Ethyl Thioglycoside Donors
Authors: Huang Jia‐Sheng , Huang Wei , Meng Xue , Wang Xin , Gao Peng‐Cheng , Yang Jin‐Song 
Published: July 2015

AbstractAn efficient methodology for the synthesis of α‐Kdo glycosidic bonds has been developed with 5,7‐O‐di‐tert‐butylsilylene (DTBS) protected Kdo ethyl thioglycosides as glycosyl donors. The approach permits a wide scope of acceptors to be used, thus affording biologically significant Kdo glycosides in good to excellent chemical yields with complete α‐selectivity. The synthetic utility of an orthogonally protected Kdo donor has been demonstrated by concise preparation of two α‐Kdo‐containing oligosaccharides.
Nickel‐katalysierte Cyclopropanierung mit NMe4OTf und nBuLi
Authors: Künzi Stefan A. , Sarria Toro Juan Manuel , den Hartog Tim , Chen Peter 
Published: July 2015

AbstractNickel wurde als Katalysator für die Cyclopropanierung von unaktivierten Olefinen durch in situ hergestelltes Lithiomethyltrimethylammoniumtriflat als Methylendonor identifiziert. Eine mechanistische Hypothese wird vorgeschlagen, welche die Entstehung eines reaktiven Nickelcarben beinhaltet, um einige interessante Beobachtungen zu erklären. Zudem beleuchten unsere Resultate einen Bericht von Franzen und Wittig aus dem Jahre 1960, der später wegen Irreproduzierbarkeit zurückgezogen wurde, und liefern eine rationale Basis für eine systematische Entwicklung der Reaktion für präparative Zwecke als Alternative zu Diazomethan oder Simmons‐Smith‐Bedingungen.
Regio‐ and Enantioselective Aza‐Diels–Alder Reactions of 3‐Vinylindoles: A Concise Synthesis of the Antimalarial Spiroindolone NITD609
Authors: Zheng Haifeng , Liu Xiaohua , Xu Chaoran , Xia Yong , Lin Lili , Feng Xiaoming 
Published: July 2015

AbstractAn asymmetric aza‐Diels–Alder reaction of 3‐vinylindoles with isatin‐derived ketimines has been developed. A series of spiroindolone derivatives were thus obtained in good to excellent yields with excellent enantioselectivity (up to 96 % yield and 99 % ee). Furthermore, the antimalarial compound NITD609 could be obtained in three steps with an overall yield of 40.6 %. Control experiments and operando IR experiments imply a concerted reaction pathway. The regioselectivity and exo selectivity result from π–π interactions between the two indoline rings of the two reactants.
Biomimetic Self‐Healing
Authors: Diesendruck Charles E. , Sottos Nancy R. , Moore Jeffrey S. , White Scott R. 
Published: July 2015

AbstractSelf‐healing is a natural process common to all living organisms which provides increased longevity and the ability to adapt to changes in the environment. Inspired by this fitness‐enhancing functionality, which was tuned by billions of years of evolution, scientists and engineers have been incorporating self‐healing capabilities into synthetic materials. By mimicking mechanically triggered chemistry as well as the storage and delivery of liquid reagents, new materials have been developed with extended longevity that are capable of restoring mechanical integrity and additional functions after being damaged. This Review describes the fundamental steps in this new field of science, which combines chemistry, physics, materials science, and mechanical engineering.
Transparent Electrodes Printed with Nanocrystal Inks for Flexible Smart Devices
Authors: Song Jizhong , Zeng Haibo 
Published: July 2015

AbstractTransparent electrodes (TEs) are crucial in a wide range of modern electronic and optoelectronic devices. However, traditional TEs cannot meet the requirements of smart devices under development in unique fields, such as electronic skins, wearable electronics, robotic skins, flexible and stretchable displays, and solar cells. Emerging TEs printed with nanocrystal (NC) inks are inexpensive and compatible with solution processes, and have huge potential in flexible, stretchable, and wearable devices. Every development in ink‐based electrodes makes them more competitive for practical applications in various smart devices. Herein, we provide an overview of emergent ink‐based electrodes, such as transparent conducting oxides, metal nanowires, graphene, and carbon nanotubes, and their application in solution‐based flexible and stretchable devices.
Vibrational Imaging of Glucose Uptake Activity in Live Cells and Tissues by Stimulated Raman Scattering
Authors: Hu Fanghao , Chen Zhixing , Zhang Luyuan , Shen Yihui , Wei Lu , Min Wei 
Published: July 2015

AbstractGlucose is a ubiquitous energy source for most living organisms. Its uptake activity closely reflects cellular metabolic demand in various physiopathological conditions. Extensive efforts have been made to specifically image glucose uptake, such as with positron emission tomography, magnetic resonance imaging, and fluorescence microscopy, but all have limitations. A new platform to visualize glucose uptake activity in live cells and tissues is presented that involves performing stimulated Raman scattering on a novel glucose analogue labeled with a small alkyne moiety. Cancer cells with differing metabolic activities can be distinguished. Heterogeneous uptake patterns are observed with clear cell–cell variations in tumor xenograft tissues, neuronal culture, and mouse brain tissues. By offering the distinct advantage of optical resolution but without the undesirable influence of fluorophores, this method will facilitate the study of energy demands of living systems with subcellular resolution.
Organocatalytic Glycosylation by Using Electron‐Deficient Pyridinium Salts
Authors: Das Somnath , Pekel Daniel , Neudörfl Jörg‐M. , Berkessel Albrecht 
Published: July 2015

AbstractA new organocatalytic glycosylation method based on electron‐deficient pyridinium salts is reported. At ambient temperature and catalyst loadings as low as 1 mol %, 2‐deoxyglycosides were formed from benzyl‐ and silyl‐protected glycals and primary or secondary glycosyl acceptors, with excellent yields and anomeric selectivity. Mechanistic investigations point to alcohol–pyridinium conjugates (1,2‐addition products) as key intermediates in the catalytic cycle.
A 6,11,16‐Triarylbiphenylcorrole with an adj‐CCNN Core: Stabilization of an Organocopper(III) Complex
Authors: Adinarayana B. , Thomas Ajesh P. , Suresh Cherumuttathu H. , Srinivasan A. 
Published: July 2015

AbstractAn adj‐dicarbacorrole with CCNN in the core is achieved by replacing the bipyrrole moiety by a simple polycyclic aromatic hydrocarbon, such as biphenyl unit. Spectroscopic studies and structural analyzes confirm the absence of macrocyclic aromatization, thus leading to overall nonaromatic character. The trianionic core is effectively utilized to stabilize a copper(III) ion to form an organocopper complex.
[Fe19] “Super‐Lindqvist” Aggregate and Large 3D Interpenetrating Coordination Polymer from Solvothermal Reactions of [Fe2(OtBu)6] with Ethanol
Authors: Nachtigall Olaf , Kusserow Matthias , Clérac Rodolphe , Wernsdorfer Wolfgang , Menzel Michael , Renz Franz , Mrozinski Jerzy , Spandl Johann 
Published: July 2015

AbstractThe syntheses, crystal structures, and physical properties of [HFe19O14(OEt)30] and {Fe11(OEt)24}∞ are reported. [HFe19O14(OEt)30] has an octahedral shape. Its core with a central Fe metal ion surrounded by six μ6‐oxo ligands is arranged in the rock salt structure. {Fe11(OEt)24}∞ is a mixed‐valence coordination polymer in which FeIII metal ions form three 3D interpenetrating (10,3)‐b nets. The arrangement of the FeIII ions can also be compared to that of Si ions in α‐ThSi2. Thus, the described structures are at the interface between molecular and solid‐state chemistry.