bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dependence of Pedersen conductance in the E and F regions and their ratio on the solar and geomagnetic activities
Authors: Sheng Cheng , Deng Yue , Lu Yang , Yue Xinan 
Published: February 2017

AbstractIonospheric conductivity plays an important role in the magnetosphere‐ionosphere coupling. The altitudinal distribution of Pedersen conductivity gives us a rough idea about the altitudinal distribution of Joule heating at high latitudes, which is of great significance regarding the response of upper atmosphere to geomagnetic energy inputs. Based on the electron density profiles derived from the Constellation Observing System for Meteorology, Ionosphere, and Climate measurements during 2009–2014, Pedersen conductivity has been estimated. A climatologic study of the height‐integrated Pedersen conductivity in both E (100–150 km) and F (150–600 km) regions, i.e., ΣPE and ΣPF, and their ratio (γP=ΣPE/ΣPF) under different solar and geomagnetic conditions has been conducted. Both ΣPE and ΣPF increase with F10.7 and Ap indices. Their ratio is smaller at higher solar flux but larger under more disturbed geomagnetic conditions. Meanwhile, an interhemispheric asymmetry has been identified in the Ap and F10.7 dependencies of γP, which also varies with local time. These results will help to improve our understanding of the variations of the altitudinal energy distribution under different solar and geomagnetic conditions and the interhemispheric asymmetry of the high‐latitude electrodynamics.
Nonlinear hierarchical control of a quad tilt‐wing UAV: An adaptive control approach
Authors: Yildiz Yildiray , Unel Mustafa , Demirel Ahmet Eren 
Published: February 2017

SummaryIn this paper, a nonlinear hierarchical adaptive control framework is proposed for the control of a quad tilt‐wing unmanned aerial vehicle (UAV). An outer loop model reference adaptive controller with robustifying terms creates required forces to be able to move the UAV on a reference trajectory, and an inner loop nonlinear adaptive controller realizes the required attitude angles to achieve these forces. A rigorous stability analysis is provided showing the boundedness of all the signals in this cascaded controller structure. The development and the stability analysis of the controller do not use any linearizations and use the full nonlinear UAV dynamics. The controller is implemented on a high‐fidelity nonlinear tilt‐wing quadrotor model in the presence of uncertainties, wind disturbances, and measurement noise as well as actuator and structural failures. In this work, in addition to earlier modeling studies, the effect of wing‐angle variations, actuator failures, and structural failures and their effect on the center of gravity of the UAV are rigorously and systematically investigated and reflected in the model. Simulation results showing the performance of the proposed controller and a comparison with the fixed controller used in earlier studies are presented in the paper.
Multiple Wins: Embracing Technology to Increase Efficiency and Maximize Efforts
Authors: Gottlieb Michael , Chan Teresa M. , Sherbino Jonathan , Yarris Lalena 
Published: February 2017

AbstractClinician educators (CEs) are challenged to produce meaningful scholarship while balancing various clinical and administrative roles. The increasing availability of technology provides new opportunities for scholarly output and dissemination. This article proposes three strategies for utilizing technology to enhance scholarly output for the busy CE. The strategies are supported by real examples of these techniques, followed by a discussion of potential limitations and future directions.
A Chirality‐Returning Sequence for the Synthesis of an Unnatural Isomer of Hirsutellone B
Authors: Sugata Hayato , Kato Ryo , Tsubogo Tetsu , Uchiro Hiromi 
Published: February 2017

AbstractHerein, we have achieved the synthesis of an unnatural isomer of hirsutellone B. Previously, we reported the total synthesis of the antituberculosis agent hirsutellone B. The key step in that synthetic strategy involved the direct construction of a highly strained 13‐membered macrocycle by utilizing an intramolecular Ullmann reaction. In this work, we studied the effect of the configuration at the C19 position on the macrocyclization of the 13‐membered ring. The central chirality at the C19 position of the cyclization precursor was specifically transferred to give the planar chirality of the enol ether moiety of the 13‐membered macrocycle, and the planar chirality was then transferred back to the central chirality at the C19 position of the final product. This chirality‐returning sequence enabled the stereoselective construction of the γ‐hydroxylactam of the 13‐membered macrocycle of the unnatural isomer of hirsutellone B.
First Stereoselective Total Synthesis of a Dimeric Naphthoquinonopyrano‐γ‐lactone: (+)‐γ‐Actinorhodin
Authors: Neumeyer Markus , Brückner Reinhard 
Published: February 2017

AbstractWe have accomplished the first total synthesis of an isomerically pure naphthoquinonopyrano‐γ‐lactone dimer, γ‐actinorhodin, in eleven steps. Two steps exploit pairs of peri‐MeO groups as unusual selectivity controls. The respective MeO groups convey the steric bulk of a bromo or iodo substituent located ortho to one MeO group as steric hindrance into the vicinity of the second MeO group. This relay effect was indispensable for exerting regiocontrol in an aromatic bromination and diastereocontrol in an oxa‐Pictet–Spengler cyclization. The absolute configuration of our target compound was established in an asymmetric Sharpless dihydroxylation of a β,γ‐unsaturated ester, which was synthesized in a Heck coupling of a bromoiodonaphthalene with ethyl vinylacetate. The dihydroxylation provided the γ‐hydroxylactone moiety of the bromonaphthalene that was used as the substrate in the oxa‐Pictet–Spengler cyclization. Dimerization to the core of γ‐actinorhodin occurred by two Suzuki couplings.
Applications of the Wittig–Still Rearrangement in Organic Synthesis
Authors: Rycek Lukas , Hudlicky Tomas 
Published: February 2017

AbstractThis Review traces the discovery of the Wittig–Still rearrangement and its applications in organic synthesis. Its relationship to Wittig rearrangements is discussed along with detailed analysis of E/Z‐ and diastereoselectivity. Modifications of the products arising from the Wittig–Still rearrangement are reviewed in the context of increased complexity in intermediates potentially useful in target‐oriented synthesis. Early applications of the Wittig–Still rearrangement to modifications of steroids are reviewed as are applications to various terpene and alkaloid natural product targets and miscellaneous compounds. To the best of our knowledge, the literature is covered through December 2016.
Selective Arene Cleavage by Direct Insertion of Iridium into the Aromatic Ring
Authors: Jakoobi Martin , Halcovitch Nathan , Whitehead George F. S. , Sergeev Alexey G. 
Published: February 2017

AbstractWe report an unprecedented selective cleavage of aromatic C−C bonds through the insertion of well‐defined iridium complexes into the aromatic ring of simple alkylarenes. The insertion occurs at 50–100 °C without the activation of weaker C−H and C−C bonds and gives unique metallacycles in high yields. Key to the success of this approach is metal‐induced deformation of the arene ring, which creates temporary ring strain and promotes direct and selective insertion of the metal into the otherwise inert arene ring C−C bonds.
Palladium‐Catalyzed Oxidative Cascade Carbonylative Spirolactonization of Enallenols
Authors: Qiu Youai , Yang Bin , Jiang Tuo , Zhu Can , Bäckvall Jan‐E. 
Published: February 2017

AbstractA highly selective palladium‐catalyzed oxidative carbonylation/carbocyclization/alkoxycarbonylation of enallenols to afford spirolactones bearing an all‐carbon quaternary center was developed. This transformation involves the overall formation of three C−C bonds and one C−O bond through a cascade insertion of carbon monoxide (CO), an olefin, and CO. Preliminary experiments on chiral anion‐induced enantioselective carbonylation/carbocyclization of enallenols afforded spirolactones with moderate enantioselectivity.
Carbonyls as Latent Alkyl Carbanions for Conjugate Additions
Authors: Dai Xi‐Jie , Wang Haining , Li Chao‐Jun 
Published: February 2017

AbstractConjugate addition of carbon nucleophiles to electron‐deficient olefins is one of the most powerful methods for forming carbon–carbon bonds. Despite great achievements in controlling the selectivity, variation of the carbon nucleophiles remains largely underexplored, with this approach relying mostly on organometallic reagents. Herein, we report that naturally abundant carbonyls can act as latent carbon nucleophiles for conjugate additions through a ruthenium‐catalyzed process, with water and nitrogen as innocuous byproducts. The key to our success is homogeneous ruthenium(II) catalysis, combined with phosphines as spectator ligands and hydrazine as the reducing agent. This chemistry allows the incorporation of highly functionalized alkyl fragments into a vast array of electron‐deficient olefins under mild reaction conditions in a reaction complementary to the classical organometallic‐reagent‐based conjugate additions mediated or catalyzed by “soft” transition metals.
Visible‐Light‐Promoted Asymmetric Cross‐Dehydrogenative Coupling of Tertiary Amines to Ketones by Synergistic Multiple Catalysis
Authors: Yang Qi , Zhang Long , Ye Chen , Luo Sanzhong , Wu Li‐Zhu , Tung Chen‐Ho 
Published: February 2017

AbstractReported herein is an unprecedented photocatalytic asymmetric cross‐dehydrogenative coupling reaction between tertiary amines and simple ketones, and it proceeds by synergistic multiple catalysis with substoichiometric amounts of a hydrogen acceptor. This process is enabled by a simple chiral primary amine catalyst through the coupling of a catalytic enamine intermediate and an iminium cation intermediate in situ generated from tetrahydroisoquinoline derivatives by coupled Ru/Co catalysis.
Low‐Temperature Anharmonicity in Cesium Chloride (CsCl)
Authors: Sist Mattia , Fischer Karl Frederik Færch , Kasai Hidetaka , Iversen Bo Brummerstedt 
Published: February 2017

AbstractAnharmonic lattice vibrations govern heat transfer in materials, and anharmonicity is commonly assumed to be dominant at high temperature. The textbook cubic ionic defect‐free crystal CsCl is shown to have an unexplained low thermal conductivity at room temperature (ca. 1 W/(m K)), which increases to around 13  W/(m K) at 25 K. Through high‐resolution X‐ray diffraction it is unexpectedly shown that the Cs atomic displacement parameter becomes anharmonic at 20 K.
Drones in Archaeology. State‐of‐the‐art and Future Perspectives
Authors: Campana Stefano 
Published: February 2017

AbstractIn addition to traditional platforms for low‐level remote sensing (balloons, kites, etc.) new and more complex automated systems [unmanned aerial vehicles (UAVs) or drones] have become available in the last decade. The success and market expansion of these platforms has been a driving force in the development of active and passive sensors specifically designed for UAVs. In the last few years archaeologists have started testing both platforms and sensors, particularly for the following applications: three‐dimensional (3D) documentation of archaeological excavations; 3D survey of monuments and historic buildings; survey of archaeological sites and landscapes; exploratory aerial survey; and the archaeological survey of woodland areas. The scale of these applications has ranged from site‐based to landscapes‐based (approximately up to about 10 km2in extent). The role of such platforms in the archaeological survey of excavations and landscapes, and in diagnostics more generally, is of great interest and is inexorably growing. Copyright © 2017 John Wiley & Sons, Ltd.
Affordable echelle spectroscopy of the eccentric HAT‐P‐2, WASP‐14, and XO‐3 planetary systems with a sub‐meter‐class telescope
Authors: Garai Z. , Pribulla T. , Hambálek Ľ. , Kundra E. , Vaňko M. , Raetz S. , Seeliger M. , Marka C. , Gilbert H. 
Published: February 2017

BackgroundA new off‐the‐shelf, low‐cost echelle spectrograph was installed recently on the 0.6‐m telescope at the Stará Lesná Observatory (Slovakia). In this paper, we describe in detail the radial velocity (RV) analysis of the first three transiting planetary systems, namely HAT‐P‐2, WASP‐14, and XO‐3, observed with this instrument.Materials and MethodsFirst, we reduced and analyzed our RV observations. Subsequently, we compared our data with previously published RV data. We were curious about the precision of our measurements in comparison to that of the RV data achieved with echelle spectrographs of other sub‐meter‐, meter‐ and 2‐m‐class telescopes. Another question was the applicability of our RV data for modeling orbital parameters. For this purpose, the previously published data were analyzed in the same way as our RV data in order to determine and compare the parameters. Finally, we combined and analyzed all used RV data per object.ResultsThe accuracy of our data is well comparable with the average RV scatter achieved with other sub‐meter and meter‐class telescopes. In comparison with 2‐m‐class telescopes, our instrumentation gives an RV scatter of about one order greater. On the other hand, our fit results show that RV data obtained with our instrumentation can be used to determine orbital parameters of these objects.ConclusionBased on our results, we can conclude that the spectrograph is a useful instrument for the study of objects with a relatively small RV amplitude. Resulting values are sufficient for exoplanet RV detections and spectroscopic follow‐up measurements of massive exoplanets on close‐in orbits.
Serieller Wohnungsbau – Der Schlüssel für mehr kostengünstigen Wohnraum in unseren Städten
Authors: Bramann Helmut 
Published: February 2017

AbstractDeutschland ist in Bewegung gekommen: Immer mehr Menschen zieht es in die Ballungszentren und Städte. Gleichzeitig stehen wir vor der Herausforderung, knapp 1 Mio. Zuwanderer mit Wohnraum zu versorgen. Hier hat sich inzwischen ein enormer Nachfragedruck aufgebaut. Seit vielen Jahren wurde im bezahlbaren Mietwohnungsbau zu wenig gebaut. Um wachsenden Wohnungsengpässen zu begegnen, müssen alle Möglichkeiten ausgelotet werden. Bestehende Standards, Vergabestrukturen, baurechtliche Rahmenbedingungen werden hinterfragt, Planungs‐ und Genehmigungsprozesse müssen beschleunigt werden. Vor allem aber gilt es, innovative Baukonzepte zu entwickeln, mit denen Wohnungen in größerer Stückzahl und angemessener architektonischer Qualität errichtet werden können. Moderne serielle Fertigungsweisen und eine stärkere Industrialisierung des Wohnungsbaus bieten hierzu den Schlüssel.
Comparison of 6‐mercaptopurine with 6‐thioguanine for the analysis of thiopurine S‐methyltransferase activity in human erythrocyte by LC–MS/MS
Authors: Mei Shenghui , Li Xindi , Gong Xiaoqing , Zhang Xiaoyi , Li Xingang , Yang Li , Zhu Leting , Zhou Heng , Liu Yonghong , Zhou Anna , Zhang Xinghu , Zhao Zhigang 
Published: February 2017

AbstractThiopurines (TPDs) are first‐line drugs in treating neuromyelitis optica spectrum disorders (NMOSD). Evaluation of thiopurine S‐methyltransferase activity (TPMT), a major determinant of TPD toxicity, before TPD treatment using 6‐mercaptopurine (6‐MP) and 6‐thioguanine (6‐TG) as substrate was suggested. However, the equivalent of the two substrates in TPMT activity evaluation was unknown, and an alternative substrate was required in TPMT activity evaluation in patients who were already taking 6‐MP or 6‐TG. Before evaluating the agreement of 6‐MP and 6‐TG in TPMT activity measurement in patients with NMOSD, the affinity of the two substrates for the active center of TPMT should be established. A computer‐based simulation indicated that 6‐MP and 6‐TG had similar affinities for the two active sites of TPMT. According to the guidelines, an LC–MS/MS method was developed and validated to evaluate the TPMT activity in human erythrocyte hemolysate using 6‐MP or 6‐TG as substrates via 1 h incubation at 37°C. The method was applied in 81 patients with NMOSD. Evaluated by Bland–Altman plot, 6‐methylmercaptopurine and 6‐methylthioguanine represented TPMT activities were in agreement with each other. Further studies are warranted to confirm the results.
Relationships between cardiorespiratory fitness, hippocampal volume, and episodic memory in a population at risk for Alzheimer's disease
Authors: Dougherty Ryan J. , Schultz Stephanie A. , Boots Elizabeth A. , Ellingson Laura D. , Meyer Jacob D. , Van Riper Stephanie , Stegner Aaron J. , Edwards Dorothy F. , Oh Jennifer M. , Einerson Jean , Korcarz Claudia E. , Koscik Rebecca L. , Dowling Maritza N. , Gallagher Catherine L. , Carlsson Cynthia M. , Rowley Howard A. , Bendlin Barbara B. , Asthana Sanjay , Hermann Bruce P. , Sager Mark A. , Stein James H. , Johnson Sterling C. , Okonkwo Ozioma C. , Cook Dane B. 
Published: February 2017

AbstractIntroductionCardiorespiratory fitness (CRF) has been shown to be related to brain health in older adults. In individuals at risk for developing Alzheimer's disease (AD), CRF may be a modifiable risk factor that could attenuate anticipated declines in brain volume and episodic memory. The objective of this study was to determine the association between CRF and both hippocampal volume and episodic memory in a cohort of cognitively healthy older adults with familial and/or genetic risk for Alzheimer's disease (AD).MethodsEighty‐six enrollees from the Wisconsin Registry for Alzheimer's Prevention participated in this study. Participants performed a graded maximal exercise test, underwent a T‐1 anatomical magnetic resonance imaging scan, and completed the Rey Auditory Verbal Learning Test (RAVLT).ResultsThere were no significant relationships between CRF and HV or RAVLT memory scores for the entire sample. When the sample was explored on the basis of gender, CRF was significantly associated with hippocampal volume for women. For men, significant positive associations were observed between CRF and RAVLT memory scores.SummaryThese results suggest that CRF may be protective against both hippocampal volume and episodic memory decline in older adults at risk for AD, but that the relationships may be gender specific.
Phosphorylation of pRb: mechanism for RB pathway inactivation in MYCN‐amplified retinoblastoma
Authors: Ewens Kathryn G. , Bhatti Tricia R. , Moran Kimberly A. , Richards‐Yutz Jennifer , Shields Carol L. , Eagle Ralph C. , Ganguly Arupa 
Published: February 2017

AbstractA small, but unique subgroup of retinoblastoma has been identified with no detectable mutation in the retinoblastoma gene (RB1) and with high levels of MYCN gene amplification. This manuscript investigated alternate pathways of inactivating pRb, the encoded protein in these tumors. We analyzed the mutation status of the RB1 gene and MYCN copy number in a series of 245 unilateral retinoblastomas, and the phosphorylation status of pRb in a subset of five tumors using immunohistochemistry. There were 203 tumors with two mutations in RB1 (RB1−/−, 83%), 29 with one (RB1+/−, 12%) and 13 with no detectable mutations (RB1+/+, 5%). Eighteen tumors carried MYCN amplification between 29 and 110 copies: 12 had two (RB1−/−) or one RB1 (RB1+/−) mutations, while six had no mutations (RB1+/+). Immunohistochemical staining of tumor sections with antibodies against pRb and phosphorylated Rb (ppRb) displayed high levels of pRb and ppRb in both RB1+/+ and RB1+/− tumors with MYCN amplification compared to no expression of these proteins in a classic RB1−/−, MYCN‐low tumor. These results establish that high MYCN amplification can be present in retinoblastoma with or without coding sequence mutations in the RB1 gene. The functional state of pRb is inferred to be inactive due to phosphorylation of pRb in the MYCN‐amplified retinoblastoma without coding sequence mutations. This makes inactivation of RB1 by gene mutation or its protein product, pRb, by protein phosphorylation, a necessary condition for initiating retinoblastoma tumorigenesis, independent of MYCN amplification.
Genetic variants in the plasminogen activator inhibitor‐1 gene are associated with an increased risk of radiation pneumonitis in lung cancer patients
Authors: Liu Bo , Tang Yang , Yi Minxiao , Liu Qingxu , Xiong Huihua , Hu Guangyuan , Yuan Xianglin 
Published: February 2017

AbstractPlasminogen activator inhibitor‐1 (PAI‐1) plays a crucial role in the process of lung injury, although its association with radiation pneumonitis (RP) is unclear. We hypothesized that genetic variants in PAI‐1 may influence the risk of RP. In this study, 169 lung cancer patients were genotyped for six single‐nucleotide polymorphisms in PAI‐1 using the Sequenom MassARRAY system. The risk of RP was evaluated by Cox proportional hazards analyses. The cumulative RP probabilities by genotype were assessed using Kaplan–Meier analyses. Univariate and multivariate analyses revealed that PAI‐1:rs7242 GT/GG was correlated with an increased occurrence of grade ≥3 RP (crude hazard ratio = 3.331; 95% confidence interval, 1.168–9.497; P = 0.024). Our results indicated that PAI‐1:rs7242 in the 3′‐untranslated region of PAI‐1 can be a predictor of grade ≥3 RP before radiotherapy.
Targeting of crosstalk between tumor and tumor microenvironment by β‐D mannuronic acid (M2000) in murine breast cancer model
Authors: Hosseini Fatemeh , Hassannia Hadi , Mahdian‐Shakib Ahmad , Jadidi‐Niaragh Farhad , Enderami Seyed Ehsan , Fattahi Mohammadjavad , Anissian Ali , Mirshafiey Abbas , Kokhaei Parviz 
Published: February 2017

AbstractMetastasis is the main cause of death in breast cancer patients. Inflammatory processes following crosstalk between tumor cells and tumor microenvironment play an important role in progression and metastasis of cancer. Hence, targeting of these interactions may represent a novel promising strategy for breast cancer therapy. So, we investigated the effects of β‐D mannuronic acid (BDM), a new antiinflammatory agent, on 4T1 breast cancer cell line both in vitro and in vivo. Proliferation assays revealed low‐cytotoxic effect of BDM on 4T1 cells. However, BDM reduced activity of MMP‐2, MMP‐9 and significantly decreased the adhesion of 4T1 cells to extracellular matrix (ECM) in a dose‐dependent manner. The in vivo results demonstrated that BDM strongly inhibits tumor growth and increases lifespan as compared with control mice. The decrease in tumor mass was associated with decreased metastasis, recruitment, and frequency of inflammatory cells in tumor tissue. Our preclinical findings demonstrated that BDM therapy not only prevents formation of chronic inflammatory response but also inhibits crosstalk between tumor cells and their microenvironment, which is associated with reduction of tumor growth and metastasis arrest. Our data imply the use of BDM therapy in future clinical trials to open a new horizon for breast cancer therapy.