bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vertical structure of the axi‐asymmetric temperature disturbance in the Venusian polar atmosphere: Comparison between radio occultation measurements and GCM results
Authors: Ando Hiroki , Imamura Takeshi , Sugimoto Norihiko , Takagi Masahiro , Kashimura Hiroki , Tellmann Silvia , Pätzold Martin , Häusler Bernd , Matsuda Yoshihisa 
Published: July 2017

AbstractVertical temperature profiles at 40–75 km around 80°N in the Venus polar vortex are retrieved over 13 Earth days almost continuously from radio occultation measurements (Venus Express radio occultation) in the Venus Express mission. They show periodical variations with a dominant period of ∼3.1 Earth days. These fluctuations are confined in an altitude range of 45–65 km with a local minimum at ∼58 km altitude, where the static stability abruptly increases with height. The phase of the temperature fluctuations is almost reversed at the 58 km level and varies little above and below this altitude. A numerical simulation of a Venusian atmospheric general circulation model (GCM) shows that the axi‐asymmetric temperature disturbance with zonal wave number 1 is predominant at 50–75 km levels in the model atmosphere. The vertical structure of the reproduced disturbance agrees quite well with that retrieved by the radio occultation measurement: amplitude of the temperature fluctuation has a local minimum and its phase is reversed at the altitude (65 km in the model) where the static stability rapidly changes as in the observations. Above and below this altitude, the phase is almost constant in the vertical direction. The relationship among the temperature, horizontal winds, and geopotential height associated with the simulated disturbance suggests that the axi‐asymmetric temperature disturbance observed in the Venus polar region can be interpreted as neutral barotropic Rossby waves related to barotropic instability in the polar region.
Emission factors of health‐ and climate‐relevant pollutants measured in home during a carbon‐finance‐approved cookstove intervention in rural India
Authors: Grieshop Andrew P. , Jain Grishma , Sethuraman Karthik , Marshall Julian D. 
Published: July 2017

AbstractWe present results of an emission characterization effort, completed as part of a larger intervention trial, of a carbon‐finance‐approved program replacing traditional cookstoves with “rocket”‐style natural draft stoves. The 100 emission tests were conducted across 31 households in control and intervention groups, with repeated tests in most households during preintervention and postintervention periods. While mean fine particulate matter (PM2.5) emission factor for intervention stoves was significantly lower than for traditional stoves in baseline measurements, they were only marginally lower than traditional stoves during follow‐up. Intervention stove PM2.5 emissions had a larger contribution from light‐absorbing (elemental) carbon than traditional stoves. Repeated measurements in control households provide evidence for strong seasonality, likely due to differences in fuel moisture/types, in traditional stove emissions, with important implications for study design. Seasonality observed in control household emission factors (baseline > follow‐up) was in the opposite direction as that observed in indoor PM2.5 concentrations (baseline < follow‐up), highlighting that seasonally varying conditions (e.g., ventilation rates) may modify the link between emissions and exposures. Emission factor differences in paired (pre/post) tests from the same households were similar to differences in the medians of entire groups, suggesting variability is dominated by test‐to‐test variation. Emission reductions from intervention stoves were significantly smaller than laboratory performance would suggest or that are required to strongly reduce exposures. Field emissions assessment like that presented here should be prioritized early in technology assessment and development to provide rigorous estimates of the benefits reasonably expected from interventions with the potential for substantial benefits to human health and the environment.
Experimental postseismic recovery of fractured rocks assisted by calcite sealing
Authors: Aben F. M. , Doan M.‐L. , Gratier J.‐P. , Renard F. 
Published: July 2017

AbstractPostseismic recovery within fault damage zones involves slow healing of coseismic fractures leading to permeability reduction and strength increase with time. To better understand this process, experiments were performed by long‐term fluid percolation with calcite precipitation through predamaged quartz‐monzonite samples subjected to upper crustal conditions of stress and temperature. This resulted in a P wave velocity recovery of 50% of its initial drop after 64 days. In contrast, the permeability remained more or less constant for the duration of the experiment. Microstructures, fluid chemistry, and X‐ray microtomography demonstrate that incipient calcite sealing and asperity dissolution are responsible for the P wave velocity recovery. The permeability is unaffected because calcite precipitates outside of the main flow channels. The highly nonparallel evolution of strength recovery and permeability suggests that fluid conduits within fault damage zones can remain open fluid conduits after an earthquake for much longer durations than suggested by the seismic monitoring of fault healing.
Frequency dependence of susceptibility in magnets with uniaxial and triaxial anisotropy
Authors: Newell A. J. 
Published: July 2017

AbstractCharacterization of minerals in rocks and soils provides a window into environmental processes and improves the interpretation of paleomagnetic measurements. Mineral composition, size, and shape can be constrained using magnetic measurements. For small minerals, a promising measurement is the frequency dependence of magnetic susceptibility. The size and shape dependence of the in‐phase componentand out‐of‐phase componentare derived for arbitrarily oriented superparamagnetic and single‐domain magnets with uniaxial and triaxial anisotropy. In a fluctuating field, a single magnet has a thermal response parallel to the easy axis and instantaneous rotation of the moment perpendicular to it. The size and temperature variations have the same form as in earlier theories in which all the magnets are aligned with the field and can be easily adapted to the methods of Shcherbakov and Fabian (2005) and Egli (2009) for finding size distributions using multiple temperatures and frequencies. These inversions are inherently nonunique and complicated by non‐SD contributions, but some robust constraints can be put on the volume distribution if the commonly used ratioχfdis 10% or greater. The anisotropy of the out‐of‐phase component (opAMS) has the same sense as thermoremanent magnetization (TRM) and can be used to correct the paleofield direction. Along with the anisotropy of the in‐phase component (ipAMS), it can be used to gain quantitative information on the deformation of the host rock. For the line/plane, or March, deformation model, opAMS and ipAMS are calculated and it is shown how they can be used to accurately represent the strain anisotropy.
Winter snow conditions on Arctic sea ice north of Svalbard during the Norwegian young sea ICE (N‐ICE2015) expedition
Authors: Merkouriadi Ioanna , Gallet Jean‐Charles , Graham Robert M. , Liston Glen E. , Polashenski Chris , Rösel Anja , Gerland Sebastian 
Published: July 2017

AbstractSnow is a crucial component of the Arctic sea ice system. Its thickness and thermal properties control heat conduction and radiative fluxes across the ocean, ice, and atmosphere interfaces. Hence, observations of the evolution of snow depth, density, thermal conductivity, and stratigraphy are crucial for the development of detailed snow numerical models predicting energy transfer through the snow pack. Snow depth is also a major uncertainty in predicting ice thickness using remote sensing algorithms. Here we examine the winter spatial and temporal evolution of snow physical properties on first‐year (FYI) and second‐year ice (SYI) in the Atlantic sector of the Arctic Ocean, during the Norwegian young sea ICE (N‐ICE2015) expedition (January to March 2015). During N‐ICE2015, the snow pack consisted of faceted grains (47%), depth hoar (28%), and wind slab (13%), indicating very different snow stratigraphy compared to what was observed in the Pacific sector of the Arctic Ocean during the SHEBA campaign (1997–1998). Average snow bulk density was 345 kg m−3 and it varied with ice type. Snow depth was 41 ± 19 cm in January and 56 ± 17 cm in February, which is significantly greater than earlier suggestions for this region. The snow water equivalent was 14.5 ± 5.3 cm over first‐year ice and 19 ± 5.4 cm over second‐year ice.
Retrieving near‐global aerosol loading over land and ocean from AVHRR
Authors: Hsu N. C. , Lee J. , Sayer A. M. , Carletta N. , Chen S.‐H. , Tucker C. J. , Holben B. N. , Tsay S.‐C. 
Published: July 2017

AbstractThe spaceborne advanced very high resolution radiometer (AVHRR) sensor data record is approaching 40 years, providing a crucial asset for studying long‐term trends of aerosol properties regionally and globally. However, due to limitations of its channels' information content, aerosol optical depth (AOD) data from AVHRR over land are still largely lacking. In this paper, we describe a new physics‐based algorithm to retrieve aerosol loading over both land and ocean from AVHRR for the first time. The over‐land algorithm is an extension of our Sea‐viewing Wide Field‐of‐view Sensor and Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue algorithm, while a simplified version of our Satellite Ocean Aerosol Retrieval algorithm is used over ocean. We compare retrieved AVHRR AOD with that from MODIS on a daily and seasonal basis and find, in general, good agreement between the two. For the satellites with equatorial crossing times within 2 h of solar noon, the spatial coverage of the AVHRR aerosol product is comparable to that of MODIS, except over very bright arid regions (such as the Sahara), where the underlying surface reflectance at 630 nm reaches the critical surface reflectance. Based upon comparisons of the AVHRR AOD against Aerosol Robotic Network data, preliminary results indicate that the expected error confidence interval envelope is around ±(0.03 + 15%) over ocean and ±(0.05 + 25%) over land for this first version of the AVHRR aerosol products. Consequently, these new AVHRR aerosol products can contribute important building blocks for constructing a consistent long‐term data record for climate studies.
The effect of target properties on transient crater scaling for simple craters
Authors: Prieur N. C. , Rolf T. , Luther R. , Wünnemann K. , Xiao Z. , Werner S. C. 
Published: July 2017

AbstractThe effects of the coefficient of friction and porosity on impact cratering are not sufficiently considered in scaling laws that predict the crater size from a known impactor size, velocity, and mass. We carried out a systematic numerical study employing more than 1000 two‐dimensional models of simple crater formation under lunar conditions in targets with varying properties. A simple numerical setup is used where targets are approximated as granular or brecciated materials, and any compression of porous materials results in permanent compaction. The results are found to be consistent with impact laboratory experiments for water, low‐strength and low‐porosity materials (e.g., wet sand), and sands. Using this assumption, we found that both the friction coefficient and porosity are important for estimating transient crater diameters as is the strength term in crater scaling laws, i.e., the effective strength. The effects of porosity and friction coefficient on impact cratering were parameterized and incorporated into π group scaling laws, and predict transient crater diameters within an accuracy of ±5% for targets with friction coefficients f ≥ 0.4 and porosities Φ = 0–30%. Moreover, 90 crater scaling relationships are made available and can be used to estimate transient crater diameters on various terrains and geological units with different coefficient of friction, porosity, and cohesion. The derived relationships are most robust for targets with Φ > 10–15%, applicable for a lunar environment, and could therefore yield significant insights into the influence of target properties on cratering statistics.
Transferred, Ultrathin Oxide Bilayers as Biofluid Barriers for Flexible Electronic Implants
Authors: Song Enming , Lee Yoon Kyeung , Li Rui , Li Jinghua , Jin Xin , Yu Ki Jun , Xie Zhaoqian , Fang Hui , Zhong Yiding , Du Haina , Zhang Jize , Fang Guanhua , Kim Yerim , Yoon Younghee , Alam Muhammad A. , Mei Yongfeng , Huang Yonggang , Rogers John A. 
Published: July 2017

AbstractThe work presented here introduces a materials strategy that involves physically transferred, ultrathin layers of silicon dioxide (SiO2) thermally grown on silicon wafers and then coated with hafnium oxide (HfO2) by atomic layer deposition, as barriers that satisfy requirements for even the most challenging flexible electronic devices. Materials and physics aspects of hydrolysis and ionic transport associated with such bilayers define their performance and reliability characteristics. Systematic experimental studies and reactive diffusion modeling suggest that the HfO2 film, even with some density of pinholes, slows dissolution of the underlying SiO2 by orders of magnitude, independent of the concentration of ions in the surrounding biofluids. Accelerated tests that involve immersion in phosphate‐buffered saline solution at a pH of 7.4 and under a constant electrical bias demonstrate that this bilayer barrier can also obstruct the transport of ions that would otherwise cause drifts in the operation of the electronics. Theoretical drift–diffusion modeling defines the coupling of dissolution and ion diffusion, including their effects on device lifetime. Demonstrations of such barriers with passive and active components in thin, flexible electronic test structures highlight the potential advantages for wide applications in chronic biointegrated devices.
Enhanced Moisture Stability of Cesium‐Containing Compositional Perovskites by a Feasible Interfacial Engineering
Authors: Li Nan , Zhu Zonglong , Dong Qingshun , Li Jiangwei , Yang Zhanlue , Chueh Chu‐Chen , Jen Alex K.‐Y. , Wang Liduo 
Published: July 2017

AbstractThe compositional perovskites have attracted broad attention due to the improved photovoltaic performance and enhanced stability compared with the single cation perovskite, such as methylammonium lead iodide and formamidinium lead iodide. In this study, the moisture stability of the widely used cesium and bromide‐containing mixed perovskites is carefully studied by characterizing the morphology, crystallization, and device performance before and after the exposure to moisture. Though the mixed perovskites possess strong resistance to moisture in the ambient air, a rapid degradation is observed when the perovskites are exposed to a high relative humidity (RH) up to 70%. The degradation is evidenced by the obvious appearance of CsPbI3 phase along with needle‐like morphology after several hours' storage in 70% RH. Moreover, to suppress the erosion of perovskites by the high‐level moisture, an interfacial engineering is introduced with phenylethylammonium iodide (PEAI). The PEAI passivation not only shows a retarded degradation but also delivers an enhanced photovoltaic performance from 13% to >17% with much improved stability under high‐level moisture. The results imply the efficacy of interfacial engineering in fabricating high‐efficiency and stable perovskite solar cells.
pHstimuli‐responsive poly(acrylamide‐co‐sodium alginate) hydrogels prepared by γ‐radiation for improved compressive strength of concrete
Authors: Ghobashy Mohamed Mohamady , Bassioni Ghada 
Published: July 2017

AbstractCross‐linking of superabsorbent hydrogels based on poly(acrylamide‐co‐sodium alginate) is carried out using60Co γ‐radiation. Hydrogels ofPAM/NaAlg with 1.5:0.5 and 1.0:1.0 w/v concentrations showed good gel contents of 87 and 66 (%) and swelling degrees in water of 3.7 and 5 (g/g) after 40 min, respectively. The chemical structure of the hydrogel is confirmed byFTIR,XRD, andESR. The morphology of the hydrogel is observed using scanning electron microscopy. Intramolecular H‐bonding in the hydrogel network is confirmed byTGAandDSC. ThepH‐responsive swelling behavior of (PAM‐co‐NaAlg) hydrogels is tested in differentpHranges showing higher swelling capacities in basic than in acidic media. This property proposes the use of (PAM‐co‐NaAlg) hydrogel as internal curing agent for concrete. The hydrogel is examined with cement weight ratios of (0.1–0.5) wt%. The study shows that cement with (PAM‐co‐NaAlg) hydrogel improves the compressive strength of cement at 0.1 and 0.2 wt%.
Postoperative complications after stapled and hand‐sewn ileal pouch‐anal anastomosis for familial adenomatous polyposis: A multicenter study
Authors: Konishi Tsuyoshi , Ishida Hideyuki , Ueno Hideki , Kobayashi Hirotoshi , Hinoi Takao , Inoue Yasuhiro , Ishida Fumio , Kanemitsu Yukihide , Yamaguchi Tatsuro , Tomita Naohiro , Matsubara Nagahide , Watanabe Toshiaki , Sugihara Kenichi 
Published: July 2017

AbstractIleal pouch‐anal anastomosis (IPAA) after total proctocolectomy (TPC) can be conducted with either hand‐sewn or stapled anastomosis for patients with familial adenomatous polyposis (FAP). Although stapled IPAA without mucosectomy has a higher risk for developing adenomas in the remnant mucosa, it is the simpler procedure with potential benefit in short‐term outcomes. However, it remains controversial as to whether stapled IPAA has any advantages in reducing postoperative complications. The aim of the present study was to compare the postoperative complications and short‐term outcomes of stapled and hand‐sewn IPAA for patients with FAP, using a multicenter cohort sample in Japan. Data of 143 patients with FAP who underwent TPC with stapled IPAA (n=37) and hand‐sewn IPAA (n=106) at 23 institutions between 2000 and 2012 were collected. Postoperative complications, proportion of ostomy, fecal continence and overall survival were compared. Overall rates of the Clavien‐Dindo grade II‐IV complications were not different between the two groups (19% in stapled vs 25% in hand‐sewn, P=.42), with significantly fewer pouch‐related complications including leakage, pelvic abscess, vaginal fistula and anastomotic stricture in stapled IPAA (none in stapled vs 11% in hand‐sewn, P=.036). There was no mortality. Proportion of ostomy at 12 months was similar (2.7% in stapled vs 4.3% in hand‐sewn, P=.26). Mean Wexner score was similar. (0.47 in stapled vs 2.0 in hand‐sewn, P=.12). Five‐year overall survival excluding Stage IV patients was 96% in both groups. Stapled IPAA is a safe option in patients with FAP with a potential benefit in reducing pouch‐related complications.
Synthesis of Benzopyrans by Enolate‐Directed Rhodium‐Catalyzed Oxidative C−H Alkenylation of 1,3‐Dicarbonyl Compounds
Authors: Bollikolla Hari Babu , Choppakatla Subrahmanyam , Polam Naresh , Thripuram Vijaya Durga , Chidipudi Suresh Reddy 
Published: July 2017

AbstractA diverse scope of 2‐aryl‐1,3‐dicarbonyl substrates was investigated in an efficient and facile enolate‐directed C−H alkenylation process using readily available electron‐deficient alkenes. The developed domino strategy works under rhodium catalysis, providing a range of benzopyran heterocycles by the formation of two distinct C−C and C−O bonds and one new six‐membered ring. The salient features of the protocol include the broad range of previously unexplored 1,3‐dicarbonyl substrates for C−H alkenylations, good functional group tolerance and rapid assembly of new benzopyrans in generally good to excellent isolated yields.
Stereospecific Decarboxylative Nazarov Cyclization Mediated by Carbon Dioxide for the Preparation of Highly Substituted 2‐Cyclopentenones
Authors: Komatsuki Keiichi , Sadamitsu Yuta , Sekine Kohei , Saito Kodai , Yamada Tohru 
Published: July 2017

AbstractHighly substituted 2‐cyclopentenones were stereospecifically and regioselectively constructed with high catalytic efficiency through Lewis‐acid catalyzed decarboxylative Nazarov cyclization of the cyclic carbonate derivative, which is prepared by reacting the propargyl alcohol with carbon dioxide in the presence of a silver catalyst. The stereochemistry of the 2‐cyclopentenone is strictly controlled by the geometry of the alkene in the starting material. This method is applicable for various substrates.
Strukturelle und elektronische Flexibilität in Hydriden von Zintl‐Phasen mit Tetrel‐Wasserstoff‐ und Tetrel‐Tetrel‐Bindung
Authors: Auer Henry , Schlegel Robert , Oeckler Oliver , Kohlmann Holger 
Published: July 2017

AbstractDie Hydrierung von Zintl‐Phasen ermöglicht die Bildung neuer Strukturmotive mit Hauptgruppenelement‐Wasserstoff‐Bindungen im Festkörper. Die Hydrierung von SrSi, BaSi und BaGe führt zu den Hydriden SrSiH5/3‐x, BaSiH5/3‐x und BaGeH5/3‐x. Die Kristallstrukturen wurden durch eine Kombination von Röntgen‐, Neutronen‐ und Elektronenbeugung sowie unter Zuhilfenahme von DFT‐Rechnungen gelöst und zeigen eine sechsfache Überstruktur im Vergleich zur wasserstofffreien Zintl‐Phase. Schichten aus verknüpften HSr4‐(HBa4‐)Tetraedern, die ein Hydridanion enthalten, wechseln sich mit Schichten aus polyanionischen Einfach‐ und Doppelketten ab, in denen Wasserstoff kovalent an Silicium oder Germanium gebunden ist. Die idealisierten chemischen Formeln EaTtH5/3 (Ea=Erdalkalimetall, Tt=Tetrelatom) lassen sich mit dem Zintl‐Klemm‐Konzept als (Ea2+)3(TtH−)(Tt2H2−)(H−)3 beschreiben, wobei alle Tt‐Atome dreibindig sind. Die Nichtstöchiometrie (SrSiH5/3‐x, x=0.17(2); BaGeH5/3‐x, x=0.10(3)) ist durch zusätzliche π‐Bindungsanteile zu erklären.
Colossal Stability of Gas‐Phase Trianions: Super‐Pnictogens
Authors: Zhao Tianshan , Zhou Jian , Wang Qian , Jena Puru 
Published: July 2017

AbstractMultiply charged negative ions are ubiquitous in nature. They are stable as crystals because of charge compensating cations; while in solutions, solvent molecules protect them. However, they are rarely stable in the gas phase because of strong electrostatic repulsion between the extra electrons. Therefore, understanding their stability without the influence of the environment has been of great interest to scientists for decades. While much of the past work has focused on dianions, work on triply charged negative ions is sparse and the search for the smallest trianion that is stable against spontaneous electron emission or fragmentation continues. Stability of BeB11(X)123− (X=CN, SCN, BO) trianions is demonstrated in the gas phase, with BeB11(CN)123− exhibiting colossal stability against electron emission by 2.65 eV and against its neutral adduct by 15.85 eV. The unusual stability of these trianions opens the door to a new class of super‐pnictogens with potential applications in aluminum‐ion batteries.
Electrophilic Amination with Nitroarenes
Authors: Rauser Marian , Ascheberg Christoph , Niggemann Meike 
Published: July 2017

AbstractAn exceptionally general electrophilic amination, which directly transforms commercially available nitroarenes into alkylated aromatic aminoboranes with zinc organyl compounds was developed. The reaction starts with a two‐step partial reduction of the nitro group to a nitrenoid, which is used in situ as the electrophilic amination reagent. To facilitate isolation, the resulting air‐ and moisture‐sensitive aminoboranes were reacted with a range of electrophiles. The method not only represents a direct transformation of nitro compounds into electrophilic amination reagents but also provides an elegant alternative to dehydrocoupling methods for the generation of aminoboranes.