bluuebunny/crossref_metadata_2025_split huggingface dataset:
Update on the Worsening Particle Radiation Environment Observed by CRaTER and Implications for Future Human Deep‐Space Exploration
Authors: Schwadron N. A. , Rahmanifard F. , Wilson J. , Jordan A. P. , Spence H. E. , Joyce C. J. , Blake J. B. , Case A. W. , de Wet W. , Farrell W. M. , Kasper J. C. , Looper M. D. , Lugaz N. , Mays L. , Mazur J. E. , Niehof J. , Petro N. , Smith C. W. , Townsend L. W. , Winslow R. , Zeitlin C. 
Published: February 2018

AbstractOver the last decade, the solar wind has exhibited low densities and magnetic field strengths, representing anomalous states that have never been observed during the space age. As discussed by Schwadron, Blake, et al. (2014, https://doi.org/10.1002/2014SW001084), the cycle 23–24 solar activity led to the longest solar minimum in more than 80 years and continued into the “mini” solar maximum of cycle 24. During this weak activity, we observed galactic cosmic ray fluxes that exceeded theERobserved small solar energetic particle events. Here we provide an update to the Schwadron, Blake, et al. (2014, https://doi.org/10.1002/2014SW001084) observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter. The Schwadron, Blake, et al. (2014, https://doi.org/10.1002/2014SW001084) study examined the evolution of the interplanetary magnetic field and utilized a previously published study by Goelzer et al. (2013, https://doi.org/10.1002/2013JA019404) projecting out the interplanetary magnetic field strength based on the evolution of sunspots as a proxy for the rate that the Sun releases coronal mass ejections. This led to a projection of dose rates from galactic cosmic rays on the lunar surface, which suggested a ∼20% increase of dose rates from one solar minimum to the next and indicated that the radiation environment in space may be a worsening factor important for consideration in future planning of human space exploration. We compare the predictions of Schwadron, Blake, et al. (2014, https://doi.org/10.1002/2014SW001084) with the actual dose rates observed by CRaTER in the last 4 years. The observed dose rates exceed the predictions by ∼10%, showing that the radiation environment is worsening more rapidly than previously estimated. Much of this increase is attributable to relatively low‐energy ions, which can be effectively shielded. Despite the continued paucity of solar activity, one of the hardest solar events in almost a decade occurred in September 2017 after more than a year of all‐clear periods. These particle radiation conditions present important issues that must be carefully studied and accounted for in the planning and design of future missions (to the Moon, Mars, asteroids, and beyond).
Seasonal Sensitivity of the Hadley Cell and Cross‐Hemispheric Responses to Diabatic Heating in an Idealized GCM
Authors: Baker Hugh S. , Mbengue Cheikh , Woollings Tim 
Published: February 2018

AbstractThe seasonal sensitivity of the Hadley cell to localized diabatic forcing is studied using a dry idealized atmospheric general circulation model. Sensitivities are broadly consistent with Hadley cell responses in observations and climate models to El Niño–Southern Oscillation and global warming‐like forcings. However, the exact seasonal sensitivity patterns highlight the importance of reducing the uncertainty in the size and position of expected anthropogenic forcings to understand how the atmospheric circulation will respond. The sensitivities reveal cross‐hemispheric Hadley cell responses that project onto the eddy‐driven jets and storm tracks. For summer hemisphere heating, the winter Hadley cell extent and jet latitude responses are highly correlated. For winter hemisphere heating, the summer Hadley cell extent and jet speed responses are highly correlated. These seasonal differences arise due to the contrast between the dominant winter Hadley cell and weaker summer Hadley cell.
Nonhalogen Solvent‐Processed Asymmetric Wide‐Bandgap Polymers for Nonfullerene Organic Solar Cells with Over 10% Efficiency
Authors: An Yongkang , Liao Xunfan , Chen Lie , Yin Jingping , Ai Qingyun , Xie Qian , Huang Bin , Liu Feng , Jen Alex K.‐Y. , Chen Yiwang 
Published: February 2018

AbstractTwo new wide‐bandgap D–A–π copolymer donor materials, PBDT‐2TC and PBDT‐S‐2TC, based on benzodithiophene and asymmetric bithiophene with one carboxylate (2TC) substituent are synthesized by a facile approach for fullerene‐free organic solar cells (OSCs). The combination of one carboxylate‐substituted thiophene with one thiophene bridge in the backbone substantially reduces the steric hindrance, thereby favoring a planar geometry for efficient charge transport and molecular packing. A reasonable highest‐occupied‐molecular‐orbital energy level in relation to that of the acceptor and balanced hole and electron transport are observed for both polymers. This asymmetric structure unit is flexible and versatile, allowing the absorption, energy levels, and morphology of the blend films to be tailored. Fullerene‐free OSCs based on PBDT‐S‐2TC:ITIC achieve a high power conversion efficiency of 10.12%. More impressively, a successful nonhalogen solvent‐processed solar cell with 9.55% efficiency is also achieved, which is one of the highest values for a fullerene‐free OSC processed using an ecofriendly solvent.
Amorphizing of Cu Nanoparticles toward Highly Efficient and Robust Electrocatalyst for CO2 Reduction to Liquid Fuels with High Faradaic Efficiencies
Authors: Duan Yan‐Xin , Meng Fan‐Lu , Liu Kai‐Hua , Yi Sha‐Sha , Li Si‐Jia , Yan Jun‐Min , Jiang Qing 
Published: February 2018

AbstractConversion of carbon dioxide (CO2) into valuable chemicals, especially liquid fuels, through electrochemical reduction driven by sustainable energy sources, is a promising way to get rid of dependence on fossil fuels, wherein developing of highly efficient catalyst is still of paramount importance. In this study, as a proof‐of‐concept experiment, first a facile while very effective protocol is proposed to synthesize amorphous Cu NPs. Unexpectedly, superior electrochemical performances, including high catalytic activity and selectivity of CO2 reduction to liquid fuels are achieved, that is, a total Faradaic efficiency of liquid fuels can sum up to the maximum value of 59% at −1.4 V, with formic acid (HCOOH) and ethanol (C2H6O) account for 37% and 22%, respectively, as well as a desirable long‐term stability even up to 12 h. More importantly, this work opens a new avenue for improved electroreduction of CO2 based on amorphous metal catalysts.
Facile Nanopatterning of PEDOT:PSS Thin Films
Authors: ElMahmoudy Mohammed , Charrier Anne M. , Malliaras George G. , Sanaur Sébastien 
Published: February 2018

AbstractNanopatterned conducting polymer poly(3,4‐ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) films are obtained using a new, facile fabrication method. In this method, an epoxy supporting layer is used to facilitate the transfer of nanopatterns from a polydimethylsiloxane mold to rigid or flexible substrates. This process overcomes several limitations that are previously introduced when using other nanopatterning techniques such as nanoimprint lithography and capillary force lithography. Two sets of nanopatterned PEDOT:PSS/Gold (Au) electrodes are fabricated with different dimensions: set 1 with 87 nm linewidth, 140 nm pitch, 30 nm depth; and set 2 with 157 nm linewidth, 280 nm pitch, 26 nm depth, respectively. The electrochemical impedance of these electrodes is measured to be lower than that of flat electrodes fabricated following the same process. These findings open the way for fabricating smaller electrodes with reduced impedance. Possible applications can be in the field of biosensing, neural recordings, and interfaces, where decreasing the contact impedance plays a key role.
Molecular Engineering Using an Anthanthrone Dye for Low‐Cost Hole Transport Materials: A Strategy for Dopant‐Free, High‐Efficiency, and Stable Perovskite Solar Cells
Authors: Pham Hong Duc , Do Thu Trang , Kim Jinhyun , Charbonneau Cecile , Manzhos Sergei , Feron Krishna , Tsoi Wing Chung , Durrant James R. , Jain Sagar M. , Sonar Prashant 
Published: February 2018

AbstractIn this report, highly efficient and humidity‐resistant perovskite solar cells (PSCs) using two new small molecule hole transporting materials (HTM) made from a cost‐effective precursor anthanthrone (ANT) dye, namely, 4,10‐bis(1,2‐dihydroacenaphthylen‐5‐yl)‐6,12‐bis(octyloxy)‐6,12‐dihydronaphtho[7,8,1,2,3‐nopqr]tetraphene (ACE‐ANT‐ACE) and 4,4′‐(6,12‐bis(octyloxy)‐6,12‐dihydronaphtho[7,8,1,2,3‐nopqr]tetraphene‐4,10‐diyl)bis(N,N‐bis(4‐methoxyphenyl)aniline) (TPA‐ANT‐TPA) are presented. The newly developed HTMs are systematically compared with the conventional 2,2′,7,7′‐tetrakis(N,N′‐di‐p‐methoxyphenylamino)‐9,9′‐spirbiuorene (Spiro‐OMeTAD). ACE‐ANT‐ACE and TPA‐ANT‐TPA are used as a dopant‐free HTM in mesoscopic TiO2/CH3NH3PbI3/HTM solid‐state PSCs, and the performance as well as stability are compared with Spiro‐OMeTAD‐based PSCs. After extensive optimization of the metal oxide scaffold and device processing conditions, dopant‐free novel TPA‐ANT‐TPA HTM‐based PSC devices achieve a maximum power conversion efficiency (PCE) of 17.5% with negligible hysteresis. An impressive current of 21 mA cm−2 is also confirmed from photocurrent density with a higher fill factor of 0.79. The obtained PCE of 17.5% utilizing TPA‐ANT‐TPA is higher performance than the devices prepared using doped Spiro‐OMeTAD (16.8%) as hole transport layer at 1 sun condition. It is found that doping of LiTFSI salt increases hygroscopic characteristics in Spiro‐OMeTAD; this leads to the fast degradation of solar cells. While, solar cells prepared using undoped TPA‐ANT‐TPA show dewetting and improved stability. Additionally, the new HTMs form a fully homogeneous and completely covering thin film on the surface of the active light absorbing perovskite layers that acts as a protective coating for underlying perovskite films. This breakthrough paves the way for development of new inexpensive, more stable, and highly efficient ANT core based lower cost HTMs for cost‐effective, conventional, and printable PSCs.
Defective Carbon–CoP Nanoparticles Hybrids with Interfacial Charges Polarization for Efficient Bifunctional Oxygen Electrocatalysis
Authors: Lin Yunxiang , Yang Li , Zhang Youkui , Jiang Hongliang , Xiao Zijian , Wu Chuanqiang , Zhang Guobin , Jiang Jun , Song Li 
Published: February 2018

AbstractThe development of efficient catalysts for both oxygen reduction and evolution reactions (oxygen reduction reaction (ORR) and oxygen evolution reaction (OER)) is central to regenerative fuel cells and rechargeable metal–air batteries. It is highly desirable to achieve the efficient integration of dual active components into the catalysts and to understand the interaction between the dual components. Here, a facile approach is demonstrated to construct defective carbon–CoP nanoparticle hybrids as bifunctional oxygen electrocatalysts, and further probe the interfacial charge distribution behavior. By combining multiple synchrotron‐based X‐ray spectroscopic characterizations with density functional theory calculations, the interfacial charge polarization with the electrons gathering at the defective carbon surface and the holes gathering at the CoP surface due to strong interfacial coupling is revealed, which simultaneously facilitates the ORR and OER with remarkable bifunctional oxygen electrode activities. This work not only offers a bifunctional oxygen catalyst with outstanding performance, but also unravels the promoting factor of the hybrids from the view of interfacial charge distribution.
Mississippian subadults from the Middle Cumberland and Eastern regions of Tennessee: Biological indicators of population interaction
Authors: Scopa Kelso Rebecca 
Published: February 2018

AbstractObjectivesHuman subadult skeletal remains can provide a unique perspective into biosocial aspects of Mississippian period population interactions within and between the Middle Cumberland (MCR) and Eastern Tennessee Regions (ETR). The majority of previous studies have concentrated on adult skeletal remains, leaving out a large and extremely important population segment.MethodsSkeletal indicators of disease, growth, body proportions, and metabolic stress were collected from subadult remains from five archaeological sites over several temporal periods. Crucial to overcoming limitations associated with the osteological paradox, the biological results were placed into an archaeological context based on prior studies as well as paleoclimatological data.ResultsResults reveal homogeneity both within and between regions for most skeletal indicators. However, MCR individuals exhibit a higher frequency of pathology than those from ETC, while stature is significantly lower in younger subadults from the MCR. Within the ETR, there is no evidence for biological differences between Early Dallas and subsequent Late Dallas and Mouse Creek cultural phases. Despite presumed signs of increased conflict at the Dallas site, frequencies and types of skeletal pathology and growth disruptions are comparable to other regional sites.ConclusionsThese findings suggest that despite cultural differences between the ETR and MCR, there was no large‐scale intrusion from an outside population into the ETR during the Late Mississippian Period, or if one occurred, it is biologically invisible. Combined with climatic and archaeobotanical data, results suggest the MCR subadults were under increased stress in their earlier years. This may have been associated with increased interpersonal violence and dependence on few food sources occurring with greater scarcity.
Locomotor activity, growth hormones, and systemic robusticity: An investigation of cranial vault thickness in mouse lines bred for high endurance running
Authors: Copes L. E. , Schutz H. , Dlugsoz E. M. , Judex S. , Garland T. 
Published: February 2018

AbstractObjectivesTo use a mouse model to investigate the relationships among the components of the systemic robusticity hypothesis (SRH): voluntary exercise on wheels, spontaneous physical activity (SPA) in cages, growth hormones, and skeletal robusticity, especially cranial vault thickness (CVT).Materials and MethodsFifty female mice from lines artificially selected for high running (HR) and 50 from nonselected control (C) lines were housed in cages with (Active) or without wheels (Sedentary). Wheel running and SPA were monitored daily. The experiment began at 24–27 days of age and lasted 12 weeks. Food consumption was measured weekly. Mice were skeletonized and their interparietal, parietal, humerus, and femur were µCT scanned. Mean total thickness of the parietal and interparietal bones was determined, along with thickness of the cortical and diploe layers individually. Geometric cross‐sectional indicators of strength were calculated for the long bones. Blood samples were assayed for IGF‐1 and IGFBP‐3.ResultsPhysical activity differed significantly among groups, based both on linetype (C vs. HR) and activity (A vs. S). However, contrary to our predictions, the ratio of IGF‐1 to IGFBP‐3 was higher in C mice than in HR mice. Neither CVT nor postcranial robusticity was affected by linetype or activity, nor were most measures of CVT and postcranial robusticity significantly associated with one another.DiscussionOur results fail to provide support for the systemic robusticity hypothesis, suggesting it is important to rethink the long‐standing theory that increased CVT in Homo erectus reflects increased physical activity compared other hominin species.
Nanobody‐Enabled Reverse Pharmacology on G‐Protein‐Coupled Receptors
Authors: Pardon Els , Betti Cecilia , Laeremans Toon , Chevillard Florent , Guillemyn Karel , Kolb Peter , Ballet Steven , Steyaert Jan 
Published: February 2018

AbstractThe conformational complexity of transmembrane signaling of G‐protein‐coupled receptors (GPCRs) is a central hurdle for the design of screens for receptor agonists. In their basal states, GPCRs have lower affinities for agonists compared to their G‐protein‐bound active state conformations. Moreover, different agonists can stabilize distinct active receptor conformations and do not uniformly activate all cellular signaling pathways linked to a given receptor (agonist bias). Comparative fragment screens were performed on a β2‐adrenoreceptor–nanobody fusion locked in its active‐state conformation by a G‐protein‐mimicking nanobody, and the same receptor in its basal‐state conformation. This simple biophysical assay allowed the identification and ranking of multiple novel agonists and permitted classification of the efficacy of each hit in agonist, antagonist, or inverse agonist categories, thereby opening doors to nanobody‐enabled reverse pharmacology.
Genexpression auf DNA‐Biochips: Strukturierung durch Strangverdrängungs‐Lithographie
Authors: Pardatscher Günther , Schwarz‐Schilling Matthaeus , Daube Shirley S. , Bar‐Ziv Roy H. , Simmel Friedrich C. 
Published: February 2018

AbstractDie lithographische Strukturierung von DNA‐Molekülen ermöglicht die räumliche Organisation von zellfreien, genetischen Schaltkreisen unter streng kontrollierten Bedingungen. Im Folgenden beschreiben wir einen biokompatiblen, DNA‐basierten Chip‐Photolack namens “Bephore”, der mittels Photo‐ und Elektronenstrahllithographie strukturiert werden kann. Das Verfahren basiert auf der Spaltung eines chemisch modifizierten, haarnadelförmigen DNA‐Moleküls durch ultraviolettes Licht oder Elektronen, und auf einer nachfolgenden DNA‐Strangverdrängungsreaktion. Hierbei werden alle Schritte in wässriger Lösung und ohne eine chemische Entwicklung des Photolacks durchgeführt, wodurch sich der lithographische Prozess als besonders robust und biokompatibel auszeichnet. Bephore eignet sich auch für ein mehrstufiges lithographisches Verfahren und erlaubt dadurch die Immobilisierung verschiedener DNA‐Moleküle mit Mikrometer‐Präzision. Als Anwendung für das Verfahren zeigen wir die Expression dreier Gene, die in Kompartimenten auf einem Chip immobilisiert wurden, und die Entstehung der daraus resultierenden, räumlichen Proteinexpressions‐Gradienten.
Li2B12 and Li3B12: Prediction of the Smallest Tubular and Cage‐like Boron Structures
Authors: Dong Xue , Jalife Said , Vásquez‐Espinal Alejandro , Ravell Estefanía , Pan Sudip , Cabellos José Luis , Liang Wei‐yan , Cui Zhong‐hua , Merino Gabriel 
Published: February 2018

AbstractAn intriguing structural transition from the quasi‐planar form of B12 cluster upon the interaction with lithium atoms is reported. High‐level computations show that the lowest energy structures of LiB12, Li2B12, and Li3B12 have quasi‐planar (Cs), tubular (D6d), and cage‐like (Cs) geometries, respectively. The energetic cost of distorting the B12 quasi‐planar fragment is overcompensated by an enhanced electrostatic interaction between the Li cations and the tubular or cage‐like B12 fragments, which is the main reason of such drastic structural changes, resulting in the smallest tubular (Li2B12) and cage‐like (Li3B12) boron structures reported to date.
Gene Expression on DNA Biochips Patterned with Strand‐Displacement Lithography
Authors: Pardatscher Günther , Schwarz‐Schilling Matthaeus , Daube Shirley S. , Bar‐Ziv Roy H. , Simmel Friedrich C. 
Published: February 2018

AbstractLithographic patterning of DNA molecules enables spatial organization of cell‐free genetic circuits under well‐controlled experimental conditions. Here, we present a biocompatible, DNA‐based resist termed “Bephore”, which is based on commercially available components and can be patterned by both photo‐ and electron‐beam lithography. The patterning mechanism is based on cleavage of a chemically modified DNA hairpin by ultraviolet light or electrons, and a subsequent strand‐displacement reaction. All steps are performed in aqueous solution and do not require chemical development of the resist, which makes the lithographic process robust and biocompatible. Bephore is well suited for multistep lithographic processes, enabling the immobilization of different types of DNA molecules with micrometer precision. As an application, we demonstrate compartmentalized, on‐chip gene expression from three sequentially immobilized DNA templates, leading to three spatially resolved protein‐expression gradients.
Electron Transfer around a Molecular Corner
Authors: Schmidt Hauke C. , Larsen Christopher B. , Wenger Oliver S. 
Published: February 2018

AbstractThe distance dependence of electron transfer (ET) is commonly investigated in linear rigid rod‐like compounds, but studies of molecular wires with integrated corners imposing 90° angles are very rare. By using spirobifluorene as a key bridging element and by substituting it at different positions, two isomeric series of donor‐bridge‐acceptor compounds with either nearly linear or angled geometries were obtained. Photoinduced ET in both series is dominated by rapid through‐bond hole hopping across oligofluorene bridges over distances of up to 70 Å. Despite considerable conformational flexibility, direct through‐space and through‐solvent ET is negligible even in the angled series. The independence of the ET rate constant on the total number of fluorene units in the angled series is attributed to a rate‐limiting tunneling step through the spirobifluorene corner. This finding is relevant for multidimensional ET systems and grids in which individual molecular wires are interlinked at 90° angles.
Manganese‐Catalyzed Carbonylative Annulations for Redox‐Neutral Late‐Stage Diversification
Authors: Liang Yu‐Feng , Steinbock Ralf , Münch Annika , Stalke Dietmar , Ackermann Lutz 
Published: February 2018

AbstractAn inexpensive, nontoxic manganese catalyst enabled unprecedented redox‐neutral carbonylative annulations under ambient pressure. The manganese catalyst outperformed all other typically used base and precious‐metal catalysts. The outstanding versatility of the manganese catalysis manifold was reflected by ample substrate scope, setting the stage for effective late‐stage manipulations under racemization‐free conditions of a wealth of marketed drugs and natural products, including alkaloids, amino acids, steroids, and carbohydrates.
A Delamination Strategy for Thinly Layered Defect‐Free High‐Mobility Black Phosphorus Flakes
Authors: Yang Sheng , Zhang Ke , Ricciardulli Antonio Gaetano , Zhang Panpan , Liao Zhongquan , Lohe Martin R. , Zschech Ehrenfried , Blom Paul W. M. , Pisula Wojciech , Müllen Klaus , Feng Xinliang 
Published: February 2018

AbstractExtraordinary electronic and photonic features render black phosphorus (BP) an important material for the development of novel electronics and optoelectronics. Despite recent progress in the preparation of thinly layered BP flakes, scalable synthesis of large‐size, pristine BP flakes remains a major challenge. An electrochemical delamination strategy is demonstrated that involves intercalation of diverse cations in non‐aqueous electrolytes, thereby peeling off bulk BP crystals into defect‐free flakes comprising only a few layers. The interplay between tetra‐n‐butylammonium cations and bisulfate anions promotes a high exfoliation yield up to 78 % and large BP flakes up to 20.6 μm. Bottom‐gate and bottom‐contact field‐effect transistors, comprising single BP flakes only a few layers thick, exhibit a high hole mobility of 252±18 cm2 V−1 s−1 and a remarkable on/off ratio of (1.2±0.15)×105 at 143 K under vacuum. This efficient and scalable delamination method holds great promise for development of BP‐based composites and optoelectronic devices.