bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interfacial atomic site characterization by photoelectron diffraction for 4H-AlN/4H-SiC(

) heterojunction
Authors: Maejima Naoyuki , Horita Masahiro , Matsui Hirosuke , Matsushita Tomohiro , Daimon Hiroshi , Matsui Fumihiko 
Published: July 2016

Abstract
The interfacial atomic structure of an AlN thin film on a nonpolar 4H-SiC(

) substrate grown by atomic Al and N plasma deposition was studied by photoelectron diffraction and spectroscopy. The epitaxial growth of the thin film was confirmed by the comparison of element-specific photoelectron intensity angular distributions (PIADs). Depth profiles were analyzed by angle-resolved constant-final-state-mode X-ray photoelectron spectroscopy (AR-XPS). No polar angular dependence was observed in Al 2p spectra, while an additional intermixing component was found in interface-sensitive N 1s spectra. The site-specific N 1s PIADs for the AlN film and an intermixing component were derived from two N 1s PIADs with different binding energies. We attributed the intermixing component to SiN interfacial layer sites. In order to prevent SiN growth at the interface, we deposited Al on the SiC(

) substrate prior to the AlN growth. A significant reduction in the amount of intermixing components at the AlN/SiC interface was confirmed by AR-XPS.
Coherent seasonal, annual, and quasi‐biennial variations in ionospheric tidal/SPW amplitudes
Authors: Chang Loren C. , Sun Yan‐Yi , Yue Jia , Wang Jack Chieh , Chien Shih‐Han 
Published: July 2016

AbstractIn this study, we examine the coherent spatial and temporal modes dominating the variation of selected ionospheric tidal and stationary planetary wave (SPW) signatures from 2007 to 2013 FORMOSAT‐3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) total electron content observations using multidimensional ensemble empirical mode decomposition (MEEMD) from the Hilbert‐Huang Transform. We examine the DW1, SW2, DE3, and SPW4 components, which are driven by a variety of in situ and vertical coupling sources. The intrinsic mode functions (IMFs) resolved by MEEMD analysis allows for the isolation of the dominant modes of variability for prominent ionospheric tidal/SPW signatures in a manner not previously used, allowing the effects of specific drivers to be examined individually. The time scales of the individual IMFs isolated for all tidal/SPW signatures correspond to a semiannual variation at equatorial ionization anomaly (EIA) latitudes maximizing at the equinoxes, as well as annual oscillations at the EIA crests and troughs. All tidal/SPW signatures show one IMF isolating an ionospheric quasi‐biennial oscillation (QBO) in the equatorial latitudes maximizing around January of odd‐numbered years. This total electron content QBO variation is in phase with a similar QBO variation isolated in both the Global Ultraviolet Imager (GUVI) zonal mean column O/N2 density ratio (ΣO/N2) and the F10.7 solar radio flux index around solar maximum, while showing temporal variation more similar to that of GUVI ΣO/N2 during the time around the 2008/2009 extended solar minimum. These results point to both quasi‐biennial variations in solar irradiance and thermosphere/ionosphere composition as a generation mechanism for the ionospheric QBO.
Does resolution of flow field observation influence apparent habitat use and energy expenditure in juvenile coho salmon?
Authors: Tullos Desirée , Walter Cara , Dunham Jason 
Published: July 2016

AbstractThis study investigated how the resolution of observation influences interpretation of how fish, juvenile Coho Salmon (Oncorhynchus kisutch), exploit the hydraulic environment in streams. Our objectives were to evaluate how spatial resolution of the flow field observation influenced: (1) the velocities considered to be representative of habitat units; (2) patterns of use of the hydraulic environment by fish; and (3) estimates of energy expenditure. We addressed these objectives using observations within a 1:1 scale physical model of a full‐channel log jam in an outdoor experimental stream. Velocities were measured with Acoustic Doppler Velocimetry at a 10 cm grid spacing, whereas fish locations and tailbeat frequencies were documented over time using underwater videogrammetry. Results highlighted that resolution of observation did impact perceived habitat use and energy expenditure, as did the location of measurement within habitat units and the use of averaging to summarize velocities within a habitat unit. In this experiment, the range of velocities and energy expenditure estimates increased with coarsening resolution (grid spacing from 10 to 100 cm), reducing the likelihood of measuring the velocities locally experienced by fish. In addition, the coarser resolutions contributed to fish appearing to select velocities that were higher than what was measured at finer resolutions. These findings indicate the need for careful attention to and communication of resolution of observation in investigating the hydraulic environment and in determining the habitat needs and bioenergetics of aquatic biota.
Origins, seasonality, and fluxes of organic matter in the Congo River
Authors: Spencer Robert G. M. , Hernes Peter J. , Dinga Bienvenu , Wabakanghanzi Jose N. , Drake Travis W. , Six Johan 
Published: July 2016

AbstractThe Congo River in central Africa represents a major source of organic matter (OM) to the Atlantic Ocean. This study examined elemental (%OC, %N, and C:N), stable isotopic (δ13C and δ15N), and biomarker composition (lignin phenols) of particulate OM (POM) and dissolved OM (DOM) across the seasonal hydrograph. Even though the Congo exhibits an extremely stable intra‐annual discharge regime, seasonal variability in OM composition was evident. DOM appears predominantly derived from vascular plant inputs with greater relative contribution during the rising limb and peak in discharge associated with the major November–December discharge maximum. Generally, POM appears to be sourced from soil‐derived mineral‐associated OM (low C:N, low Λ8, and higher (Ad:Al)v) but the relative proportion of fresh vascular plant material (higher C:N, higher Λ8, and lower (Ad:Al)v) increases with higher discharge. During the study period (September 2009 to November 2010) the Congo exported 29.21 Tg yr−1 of total suspended sediment (TSS), 1.96 Tg yr−1 of particulate organic carbon (POC), and 12.48 Tg yr−1 of dissolved organic carbon. The Congo exports an order of magnitude lower TSS load in comparison to other major riverine sources of TSS (e.g., Ganges and Brahmaputra), but due to its OM‐rich character it actually exports a comparable amount of POC. The Congo is also 2.5 times more efficient at exporting dissolved lignin per unit volume compared to the Amazon. Including Congo dissolved lignin data in residence time calculations for lignin in the Atlantic Ocean results in an approximately 10% reduction from the existing estimate, suggesting that this material is more reactive than previously thought.
Verification of high‐speed solar wind stream forecasts using operational solar wind models
Authors: Reiss Martin A. , Temmer Manuela , Veronig Astrid M. , Nikolic Ljubomir , Vennerstrom Susanne , Schöngassner Florian , Hofmeister Stefan J. 
Published: July 2016

AbstractHigh‐speed solar wind streams emanating from coronal holes are frequently impinging on the Earth's magnetosphere causing recurrent, medium‐level geomagnetic storm activity. Modeling high‐speed solar wind streams is thus an essential element of successful space weather forecasting. Here we evaluate high‐speed stream forecasts made by the empirical solar wind forecast (ESWF) and the semiempirical Wang‐Sheeley‐Arge (WSA) model based on the in situ plasma measurements from the Advanced Composition Explorer (ACE) spacecraft for the years 2011 to 2014. While the ESWF makes use of an empirical relation between the coronal hole area observed in Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) images and solar wind properties at the near‐Earth environment, the WSA model establishes a link between properties of the open magnetic field lines extending from the photosphere to the corona and the background solar wind conditions. We found that both solar wind models are capable of predicting the large‐scale features of the observed solar wind speed (root‐mean‐square error, RMSE ≈100 km/s) but tend to either overestimate (ESWF) or underestimate (WSA) the number of high‐speed solar wind streams (threat score, TS ≈ 0.37). The predicted high‐speed streams show typical uncertainties in the arrival time of about 1 day and uncertainties in the speed of about 100 km/s. General advantages and disadvantages of the investigated solar wind models are diagnosed and outlined.
The late prehistoric introduction of pottery to Rossel Island, Louisiade Archipelago, Papua New Guinea: Insights into local social organisation and regional exchange in the Massim
Authors: SHAW BEN 
Published: July 2016

AbstractThe introduction and exchange of pottery between Pacific Islands can provide insight into interaction and social organisation from both regional and local perspectives. In the Massim island region of far eastern Papua New Guinea, pottery is present in the archaeological record from 2800 to 2600 calBP. However, on Rossel Island, a relatively isolated landmass in the far east of the Louisiade Archipelago, archaeological excavation and AMS dating of several sites has determined that pottery on this island was a late prehistoric introduction, from 550–500 calBP. The introduction of pottery coincided with the establishment of increasingly complex exchange networks in the Massim, namely the Kula. It is argued in this paper that the desire for Kula participants to obtain high‐quality shell necklaces (bagi), which are prominently manufactured on Rossel, led to the island becoming more actively involved in down‐the‐line regional exchange. Pottery is largely found on the western end of Rossel, where most bagi are manufactured. The uneven distribution of pottery across the island is further argued to indicate a socio‐economic/political divide between the populations living on the western and eastern ends, which is supported by linguistic and anthropological evidence.
Improvement in Aqueous Solubility of Retinoic Acid Receptor (RAR) Agonists by Bending the Molecular Structure
Authors: Hiramatsu Michiaki , Ichikawa Yuki , Tomoshige Shusuke , Makishima Makoto , Muranaka Atsuya , Uchiyama Masanobu , Yamaguchi Takao , Hashimoto Yuichi , Ishikawa Minoru 
Published: July 2016

AbstractAqueous solubility is a key requirement for many functional molecules, e. g., drug candidates. Decrease of the partition coefficient (log P) by chemical modification, i.e., introduction of hydrophilic group(s) into molecules, is a classical strategy for improving aqueous solubility. We have been investigating alternative strategies for improving the aqueous solubility of pharmaceutical compounds by disrupting intermolecular interactions. Here, we show that introducing a bend into the molecular structure of retinoic acid receptor (RAR) agonists by changing the substitution pattern from para to meta or ortho dramatically enhances aqueous solubility by up to 890‐fold. We found that meta analogs exhibit similar hydrophobicity to the parent para compound, and have lower melting points, supporting the idea that the increase of aqueous solubility was due to decreased intermolecular interactions in the solid state as a result of the structural changes.
Environmentally‐Safe Conditions for a Palladium‐Catalyzed Direct C3‐Arylation with High Turn Over Frequency of Imidazo[1,2‐b]pyridazines Using Aryl Bromides and Chlorides
Authors: Chikhi Sabah , Djebbar Safia , Soulé Jean‐François , Doucet Henri 
Published: July 2016

AbstractPd(OAc)2 was found to catalyze very efficiently the direct arylation of imidazo[1,2‐b]pyridazine at C3‐position under a very low catalyst loading and phosphine‐free conditions. The reaction can be performed in very high TOFs and TONs employing as little as 0.1–0.05 mol % catalyst using a wide range of aryl bromides. In addition, some electron‐deficient aryl chlorides were also found to be suitable substrates. Moreover, 31 examples of the cross couplings were reported using green, safe, and renewable solvents, such as pentan‐1‐ol, diethylcarbonate or cyclopentyl methyl ether, without loss of efficiency.
An Azaacene Derivative as Promising Electron‐Transport Layer for Inverted Perovskite Solar Cells
Authors: Gu Pei‐Yang , Wang Ning , Wu Anyang , Wang Zilong , Tian Miaomiao , Fu Zhisheng , Sun Xiao Wei , Zhang Qichun 
Published: July 2016

AbstractIt is highly desirable to develop novel n‐type organic small molecules as an efficient electron‐transport layer (ETL) for the replacement of PCBM to obtain high‐performance metal‐oxide‐free, solution‐processed inverted perovskite solar cells (PSCs) because this type of solar cells with a low‐temperature and solution‐based process would make their fabrication more feasible and practical. In this research, the new azaacene QCAPZ has been synthesized and employed as non‐fullerene ETL material for inverted PSCs through a solution‐based process without the need for additional dopants or additives. The as‐fabricated inverted PSCs show a power conversion efficiency up to 10.26 %. Our results clearly suggest that larger azaacenes could be promising electron‐transport materials to achieve high‐performance solution‐processed inverted PSCs.
Noria: A Highly Xe‐Selective Nanoporous Organic Solid
Authors: Patil Rahul S. , Banerjee Debasis , Simon Cory M. , Atwood Jerry L. , Thallapally Praveen K. 
Published: July 2016

AbstractSeparation of xenon and krypton is of industrial and environmental concern; the existing technologies use cryogenic distillation. Thus, a cost‐effective, alternative technology for the separation of Xe and Kr and their capture from air is of significant importance. Herein, we report the selective Xe uptake in a crystalline porous organic oligomeric molecule, noria, and its structural analogue, PgC‐noria, under ambient conditions. The selectivity of noria towards Xe arises from its tailored pore size and small cavities, which allows a directed non‐bonding interaction of Xe atoms with a large number of carbon atoms of the noria molecular wheel in a confined space.
Understanding Interactions between Cellular Matrices and Metal Complexes: Methods To Improve Silver Nanodot‐Specific Staining
Authors: Choi Sungmoon , Yu Junhua 
Published: July 2016

AbstractMetal complexes are frequently used for biological applications due to their special photophysical and chemical characteristics. Due to strong interactions between metals and biomacromolecules, a random staining of cytoplasm or nucleoplasm by the complexes results in a low signal‐to‐background ratio. In this study, we used luminescent silver nanodots as a model to investigate the major driving force for non‐specific staining in cellular matrices. Even though some silver nanodot emitters exhibited excellent specific staining of nucleoli, labeling with nanodots was problematic owing to severe non‐specific staining. Binding between silver and sulfhydryl group of proteins appeared to be the major factor that enforced the silver staining. The oxidation of thiol groups in cells with hexacyanoferrate(III) dramatically weakened the silver‐cell interaction and consequently significantly improved the efficiency of targeted staining.
Trifluoromethylthiolation and Trifluoromethylselenolation of α‐Diazo Esters Catalyzed by Copper
Authors: Matheis Christian , Krause Thilo , Bragoni Valentina , Goossen Lukas J. 
Published: July 2016

Abstractα‐Diazo esters are smoothly converted into the corresponding trifluoromethyl thio‐ or selenoethers by reaction with Me4NSCF3 or Me4NSeCF3, respectively, in the presence of catalytic amounts of copper thiocyanate. This straightforward method gives high yields under neutral conditions at room temperature and is applicable to a wide range of functionalized molecules, including diverse α‐amino acid derivatives. It is well‐suited for the late‐stage introduction of trifluoromethylthio or ‐seleno groups into drug‐like molecules.
Synthesis and Biological Evaluation of Iodoglucoazomycin (I‐GAZ), an Azomycin–Glucose Adduct with Putative Applications in Diagnostic Imaging and Radiotherapy of Hypoxic Tumors
Authors: Kumar Piyush , Elsaidi Hassan R. H. , Zorniak Bohdarianna , Laurens Evelyn , Yang Jennifer , Bacchu Veena , Wang Monica , Wiebe Leonard I. 
Published: July 2016

AbstractIodoglucoazomycin (I‐GAZ; N‐(2‐iodo‐3‐(6‐O‐glucosyl)propyl)‐2‐nitroimidazole), a non‐glycosidic nitroimidazole–6‐O‐glucose adduct, was synthesized, radioiodinated, and evaluated as a substrate of glucose transporter 1 (GLUT1) for radiotheranostic (therapy+diagnostic) management of hypoxic tumors. Nucleophilic iodination of the nosylate synthon of I‐GAZ followed by deprotection afforded I‐GAZ in 74 % overall yield. I‐GAZ was radioiodinated via ‘exchange’ labeling using [123/131I]iodide (50–70 % RCY) and then purified by Sep‐Pak™ (>96 % RCP). [131I]I‐GAZ was stable in 2 % ethanolic solution in sterile water for 14 days when stored at 5 °C. In cell culture, I‐GAZ was found to be nontoxic to EMT‐6 cells at concentrations <0.5 mm, and weakly radiosensitizing (SER 1.1 at 10 % survival of EMT‐6 cells; 1.2 at 0.1 % survival in MCF‐7 cells). The hypoxic/normoxic uptake ratio of [123I]I‐GAZ in EMT‐6 cells was 1.46 at 2 h, and under normoxic conditions the uptake of [123I]I‐GAZ by EMT‐6 cells was unaltered in the presence of 5 mm glucose. The biodistribution of [131I]I‐GAZ in EMT‐6 tumor‐bearing Balb/c mice demonstrated rapid clearance from blood and extensive renal and hepatic excretion. Tumor/blood and tumor/muscle ratios reached ∼3 and 8, respectively, at 4 h post‐injection. Regression analysis of the first order polynomial plots of the blood and tumor radioactivity concentrations supported a perfusion–excretion model with low hypoxia‐dependent binding. [131I]I‐GAZ was found to be stable in vivo, and did not deiodinate.
Chemotherapy use and adoption of new agents is affected by age and comorbidities in patients with metastatic colorectal cancer
Authors: Vijayvergia Namrata , Li Tianyu , Wong Yu‐Ning , Hall Michael J. , Cohen Steven J. , Dotan Efrat 
Published: July 2016

BACKGROUNDThe treatment of metastatic colorectal cancer (mCRC) has changed substantially in the last 2 decades, but to the authors' knowledge, the effect of age and comorbidities on chemotherapy use has not been well studied to date.METHODSPatients with mCRC who were being treated with 5‐fluorouracil (5‐FU)‐based chemotherapy between January 1995 to December 2009 were studied using the LifeLink Health Plan Claims Database. The cohort was divided into older (aged >70 years) and younger (aged ≤70 years) patients. The Charlson Comorbidity Index (CCI) was used to assess comorbidity burden. The Wilcoxon and chi‐square tests were used in univariate and logistic regression in multivariate analyses.RESULTSA total of 16,087 patients were identified, with 24% of the patients who were receiving chemotherapy being aged >70 years. The percentage of patients with a CCI >1 receiving chemotherapy increased over time (14% in 1996 vs 40% after 2004; P<.05). Older patients were less likely to receive treatment with >2 agents compared with younger patients (15% vs.22% and 11% vs.16%, respectively, in 2003 and 2009; P<.001). After approval by the US Food and Drug Administration in 1998, the use of irinotecan was lower in older compared with younger patients, a difference that resolved by 2002 (15% vs 38% [P<.05]; 62% in both groups [P = .9], respectively). Similarly, oxaliplatin was used more frequently in younger patients in 2003 (22% vs 15%; P<.05), with a decrease in this difference noted by 2009 (64% vs 60%; P = .95). On multivariate analysis, older age (odds ratio, 0.65; P<.001) and a CCI >1 (odds ratio, 0.84; P<.001) were found to be associated with a lower likelihood of receiving combination chemotherapy.CONCLUSIONSIn this commercially insured population, the percentage of older patients treated for mCRC was low, and the rate of chemotherapy adoption was found to lag behind that of younger patients. However, the percentage of older patients with comorbidities receiving therapy increased over time. Cancer 2016;122:3191–8. © 2016 American Cancer Society.
Water level regulation affects niche use of a lake top predator, Arctic charr (Salvelinus alpinus)
Authors: Eloranta Antti P. , Sánchez‐Hernández Javier , Amundsen Per‐Arne , Skoglund Sigrid , Brush Jaclyn M. , Henriksen Eirik H. , Power Michael 
Published: July 2016

AbstractWater level fluctuations are expected to deteriorate the littoral zone in heavily regulated hydropower reservoirs, but there is limited empirical evidence of how food webs and fish populations are affected. We contrasted the size, growth, condition, niche use (i.e., habitat and diet), and parasite infection of allopatric Arctic charr (Salvelinus alpinus) populations in two neighboring and comparable Norwegian mountain lakes. We hypothesized that the presumed abiotic and biotic deterioration of the littoral zone would lead to reduced abundance and growth as well as to increased pelagic niche use and reduced niche width of the charr in the heavily regulated Govdajavri (maximum regulation amplitude 24 m) as compared with the unregulated Cazajavri. Our stable isotope and parasite data showed that charr had a slightly narrower and more pelagic feeding niche in the regulated than in the unregulated lake. The relative abundance of charr was lower in the regulated lake, but no between‐lake differences were observed in charr condition, and the charr grew slightly faster in the regulated than in the unregulated lake. Our study suggests that impaired littoral production can alter food webs in alpine hydropower reservoirs and induce a pelagic niche shift by top predators. These results argue for further investigations of hydropower impacts on lake food webs along with other factors that influence the abundance and niche use of fish, such as intraspecific interactions and compensatory growth, which may partly mask the potential impacts.