bluuebunny/crossref_metadata_2025_split huggingface dataset:
CLUSIM: A Synthetic Aperture Radar Clutter Simulator for Planetary Exploration
Authors: Ilyushin Ya. A. , Orosei R. , Witasse O. , Sánchez‐Cano B. 
Published: September 2017

AbstractIn this paper we present the CLUtter SIMulator (CLUSIM), a special program simulating radar side echoes from rough planetary surfaces using realistic topography data sets. A numerical model of realistic topography of the Martian surface, based on Mars Orbiter Laser Altimeter data, is developed. A specially developed computer routine for evaluation of wideband radar echoes reflected from rough surfaces, capable of aperture synthesis simulation, is described. A synthetic radargram for a portion of Mars Express (MEX) orbit 9466 is computed and validated against experimental data obtained by the MARSIS radar instrument. Finally, a previously developed ionospheric phase correction procedure is numerically tested with new simulated echo signals. Impact of the surface clutter on the ionospheric correction procedure is investigated with a direct numerical comparison to a known benchmark result, which shows robustness of the correction algorithm with respect to the surface clutter.
Climatology of the Auroral Electrojets Derived From the Along‐Track Gradient of Magnetic Field Intensity Measured by POGO, Magsat, CHAMP, and Swarm
Authors: Smith A. R. A. , Beggan C. D. , Macmillan S. , Whaler K. A. 
Published: September 2017

AbstractThe auroral electrojets (AEJs) are complex and dynamic horizontal ionospheric electric currents which form ovals around Earth's poles, being controlled by the morphology of the main magnetic field and the energy input from the solar wind interaction with the magnetosphere. The strength and location of the AEJ varies with solar wind conditions and the solar cycle but should also be controlled on decadal timescales by main field secular variation. To determine the AEJ climatology, we use data from four polar Low Earth Orbit magnetic satellite missions: POGO, Magsat, CHAMP, and Swarm. A simple estimation of the AEJ strength and latitude is made from each pass of the satellites, from peaks in the along‐track gradient of the magnetic field intensity after subtracting a core and crustal magnetic field model. This measure of the AEJ activity is used to study the response in different sectors of magnetic local time (MLT) during different seasons and directions of the interplanetary magnetic field (IMF). We find a season‐dependent hemispherical asymmetry in the AEJ response to IMF By, with a tendency toward stronger (weaker) AEJ currents in the north than the south during By>0 (By<0) around local winter. This effect disappears during local summer when we find a tendency toward stronger currents in the south than the north. The solar cycle modulation of the AEJ and the long‐term shifting of its position and strength due to the core field variation are presented as challenges to internal field modeling.
Automatic Near‐Real‐Time Detection of CMEs in Mauna Loa K‐Cor Coronagraph Images
Authors: Thompson W. T. , St. Cyr O. C. , Burkepile J. T. , Posner A. 
Published: September 2017

AbstractA simple algorithm has been developed to detect the onset of coronal mass ejections (CMEs), together with speed estimates, in near‐real time using linearly polarized white‐light solar coronal images from the Mauna Loa Solar Observatory K‐Cor telescope. Ground observations in the low corona can warn of CMEs well before they appear in space coronagraphs. The algorithm used is a variation on the Solar Eruptive Event Detection System developed at George Mason University. It was tested against K‐Cor data taken between 29 April 2014 and 20 February 2017, on days identified as containing CMEs. This resulted in testing of 139 days' worth of data containing 171 CMEs. The detection rate varied from close to 80% when solar activity was high down to as low as 20–30% when activity was low. The difference in effectiveness with solar cycle is attributed to the relative prevalence of strong CMEs between active and quiet periods. There were also 12 false detections, leading to an average false detection rate of 8.6%. The K‐Cor data were also compared with major solar energetic particle (SEP) storms during this time period. There were three SEP events detected either at Earth or at one of the two STEREO spacecraft when K‐Cor was observing during the relevant time period. The algorithm successfully generated alerts for two of these events, with lead times of 1–3 h before the SEP onset at 1 AU. The third event was not detected by the automatic algorithm because of the unusually broad width in position angle.
A game theory analysis of green infrastructure stormwater management policies
Authors: William Reshmina , Garg Jugal , Stillwell Ashlynn S. 
Published: September 2017

AbstractGreen stormwater infrastructure has been demonstrated as an innovative water resources management approach that addresses multiple challenges facing urban environments. However, there is little consensus on what policy strategies can be used to best incentivize green infrastructure adoption by private landowners. Game theory, an analysis framework that has historically been under‐utilized within the context of stormwater management, is uniquely suited to address this policy question. We used a cooperative game theory framework to investigate the potential impacts of different policy strategies used to incentivize green infrastructure installation. The results indicate that municipal regulation leads to the greatest reduction in pollutant loading. However, the choice of the “best” regulatory approach will depend on a variety of different factors including politics and financial considerations. Large, downstream agents have a disproportionate share of bargaining power. Results also reveal that policy impacts are highly dependent on agents' spatial position within the stormwater network, leading to important questions of social equity and environmental justice.
Introduction to passive electron intensity modulation
Authors: Hogstrom Kenneth R. , Carver Robert L. , Chambers Erin L. , Erhart Kevin 
Published: September 2017

AbstractThis work introduces a new technology for electron intensity modulation, which uses small area island blocks within the collimating aperture and small area island apertures in the collimating insert. Due to multiple Coulomb scattering, electrons contribute dose under island blocks and lateral to island apertures. By selecting appropriate lateral positions and diameters of a set of island blocks and island apertures, for example, a hexagonal grid with variable diameter circular island blocks, intensity modulated beams can be produced for appropriate air gaps between the intensity modulator (position of collimating insert) and the patient. Such a passive radiotherapy intensity modulator for electrons (PRIME) is analogous to using physical attenuators (metal compensators) for intensity modulated x‐ray therapy (IMXT). For hexagonal spacing, the relationship between block (aperture) separation (r) and diameter (d) and the local intensity reduction factor (IRF) is discussed. The PRIME principle is illustrated using pencil beam calculations for select beam geometries in water with half beams modulated by 70%–95% and for one head and neck field of a patient treated with bolus electron conformal therapy. Proof of principle is further illustrated by showing agreement between measurement and calculation for a prototype PRIME. Potential utilization of PRIME for bolus electron conformal therapy, segmented‐field electron conformal therapy, modulated electron radiation therapy, and variable surface geometries is discussed. Further research and development of technology for the various applications is discussed. In summary, this paper introduces a practical, new technology for electron intensity modulation in the clinic, demonstrates proof of principle, discusses potential clinical applications, and suggests areas of further research and development.
Back to the Future: The Everyday Built Environment in a Phase of Transition
Authors: Habraken John 
Published: September 2017

Time is a crucial dimension in architecture, yet architectural education ignores it. While historical environments were able to evolve over centuries, the purist spirit that has prevailed since the advent of Modernism is at odds with the social dynamics of normal human life.John Habraken – a renowned architectural educator and writer both in the Netherlands and the US – examines the issues and argues for a more effective distribution of design control, showcasing recent projects in the Netherlands and Denmark that have achieved this.
High Performance Flexible Nonvolatile Memory Based on Vertical Organic Thin Film Transistor
Authors: Hu Daobing , Wang Xiumei , Chen Huipeng , Guo Tailiang 
Published: September 2017

AbstractFlexible floating‐gate organic transistor memory (FGOTM) is a potential candidate for emerging memory technologies. Unfortunately, conventional planar FGOTM suffers from weak driving ability and insufficient mechanical flexibility, which limits its commercial application. In this work, a novel flexible vertical FGOTM (VFGOTM) is reported. Benefitting from new vertical architecture, VFGOTM provides ultrashort channel length to afford an extremely high current density. Meanwhile, VFGOTM devices exhibit excellent memory performance and outstanding retention property. The memory properties of VFGOTM devices are comparable or even better than traditional planar FGOTM and much better than the reported organic nonvolatile memory with vertical transistor structures. More importantly, organic nonvolatile memory with vertical transistor structures is investigated for the first time on a flexible substrate. The results show that VFGOTM architecture allows vertical current flow across the channel layer to effectively eliminate the effect of mechanical bending during current transport, which significantly improves the mechanical stability of the flexible VFGOTM. Hence, with a combination of excellent driving ability, memory performance, and mechanical stability, VFGOTM devices meet the practical requirements for high performance memory applications, which have great potential for the application in a wide range of flexible and wearable electronics.
High Polarity Poly(vinylidene difluoride) Thin Coating for Dendrite‐Free and High‐Performance Lithium Metal Anodes
Authors: Luo Jing , Fang Chia‐Chen , Wu Nae‐Lih 
Published: September 2017

AbstractThe high‐polarity β‐phase poly(vinylidene difluoride) (β‐PVDF), which has all trans conformation with F and H atoms located on the opposite sides of the polymer backbone, is demonstrated to be a promising artificial solid‐electrolyte interphase coating on both Cu and Li metal anodes for dendrite‐free Li deposition/stripping and enhanced cycling performance. A thin (≈4 µm) β‐PVDF coating on Cu enables uniform Li deposition/stripping at high current densities up to 5 mA cm−2, Li‐plating capacity loadings of up to 4 mAh cm−2, and excellent cycling stability over hundreds of cycles under practical conditions (1 mA cm−2 with 2 mAh cm−2). Full cells containing an LiFePO4 cathode and an anode of either β‐PVDF coated Cu or Li also exhibit excellent cycling stability. The profound effects of the high‐polarity PVDF coating on dendrite suppression are attributed to the electronegative F‐rich interface that favors layer‐by‐layer Li deposition. This study offers a new strategy for the development of dendrite‐free metal anode technology.
Eine NMR‐Methode zur Bestimmung der Bindungsreihenfolge supramolekularer Liganden an basische Reste in Proteinen
Authors: Hogeweg Anna , Sowislok Andrea , Schrader Thomas , Beuck Christine 
Published: September 2017

AbstractDie Erkennung von Proteinoberflächen, die in Protein‐Protein‐Wechselwirkungen eine Rolle spielen, entwickelt sich zu einem Fokus der supramolekularen Chemie. NMR‐Spektroskopie ist die Methode der Wahl, um Bindungsstellen von Liganden mittels Signalverschiebung und Linienverbreiterung zu identifizieren. Für große aromatische Liganden ist dies anhand klassischer NMR‐Spektren oft jedoch nicht eindeutig möglich. Wir verwenden Lys‐ und Arg‐spezifische H2(C)N‐NMR‐Experimente, um die Seitenkettenatome, die in engem Kontakt mit den Liganden stehen und für die die größten Änderungen in den NMR‐Signalen zu erwarten sind, direkt zu beobachten. Dazu wurde die Bindung von Lys‐ und Arg‐spezifischen supramolekularen Pinzetten und einem Calixaren an zwei Modellproteine untersucht. In den H2(C)N‐Spektren sind Signale für die terminalen CH2‐Gruppen aller Lys‐ und Arg‐Reste sichtbar und anhand signifikanter Unterschiede in ihren Intensitäten oder Verschiebungen kann die Bindungsreihenfolge eines Liganden eindeutig identifiziert werden.
Green synthesis of new pyrimido[4,5‐d]pyrimidine derivatives using 7‐aminonaphthalene‐1,3‐disulfonic acid‐functionalized magnetic Fe3O4@SiO2 nanoparticles as catalyst
Authors: Ghorbani‐Vaghei Ramin , Sarmast Narges 
Published: September 2017

AbstractWe, herein, describe a novel, simple, efficient and one‐pot multi‐component procedure for the synthesis of substituted pyrimido[4,5‐d]pyrimidines via reaction of N,N‐dimethyl‐6‐amino uracil, isothiocyanate and aromatic aldehydes promoted by 7‐aminonaphthalene‐1,3‐disulfonic acid (ANDSA)‐functionalized magnetic Fe3O4@SiO2 in water as solvent and without using any other harmful organic reagents. Compared with other reactions, using these organic–inorganic hybrid heterogeneous catalysts can help us to achieve a green procedure, high catalytic activity, easy recovery with an external magnetic field, and short reaction times.
Taxadiene‐5α‐ol is a minor product of CYP725A4 when expressed in Escherichia coli
Authors: Sagwan‐Barkdoll Laxmi , Anterola Aldwin M. 
Published: September 2017

AbstractCYP725A4 is a P450 enzyme from Taxus cuspidata that catalyzes the formation of taxadiene‐5α‐ol (T5α‐ol) from taxadiene in paclitaxel biosynthesis. Past attempts expressing CYP725A4 in heterologous hosts reported the formation of 5(12)‐oxa‐3(11)‐cyclotaxane (OCT) and/or 5(11)‐oxa‐3(11)‐cyclotaxane (iso‐OCT) instead of, or in addition to, T5α‐ol. Here, we report that T5α‐ol is produced as a minor product by Escherichia coli expressing both taxadiene synthase and CYP725A4. The major products were OCT and iso‐OCT, while trace amounts of unidentified monooxygenated taxanes were also detected by gas chromatography–mass spectrometry. Since OCT and iso‐OCT had not been found in nature, we tested the hypothesis that protein–protein interaction of CYP725A4 with redox partners, such as cytochrome P450 reductase (CPR) and cytochrome b5, may affect the products formed by CYP725A4, possibly favoring the formation of T5α‐ol over OCT and iso‐OCT. Our results show that coexpression of CYP725A4 with CPR from different organisms did not change the relative ratios of OCT, iso‐OCT, and T5α‐ol, while cytochrome b5 decreased overall levels of the products formed. Although unsuccessful in finding conditions that promote T5α‐ol formation over other products, we used our results to clarify conflicting claims in the literature and discuss other possible approaches to produce paclitaxel via metabolic and enzyme engineering.
Zum Verbundverhalten von Betonschraubdübeln mit großem Durchmesser
Authors: Lechner Johannes , Fleischhacker Nikolaus , Waltl Christoph , Feix Jürgen 
Published: September 2017

AbstractDas Verbundverhalten von Betonschrauben mit großem Durchmesser wird mittels Auszugsversuchen mit enger Stützung untersucht. Durch das Eindrehen von Betonschrauben in das erstellte Bohrloch wird eine kraftschlüssige Verbindung hergestellt, über deren Verhalten wenig bekannt ist. Zusätzlich zur konventionellen Installation auf Basis des Hinterschnitts wurde eine Variante mit zusätzlichem Verbundmörtel untersucht. In ersten Versuchen wird der Einfluss der Verbundlänge der Schrauben auf das Tragverhalten durch Variation der Anzahl an Gewindegängen für verschiedene Betondruckfestigkeiten betrachtet. Um genauere Auskunft über die Spannungsverteilung im Kraftübertragungsbereich zu erhalten, wurden anschließend zwei Arten von Messschrauben mit Dehnmessstreifen im Verbundbereich entwickelt. Aus den Erkenntnissen, die mit diesen Messschrauben gewonnen wurden, wird eine Ansatzfunktion abgeleitet, mit welcher die Verteilung der Längsspannung beschrieben werden kann. Aus dieser Verteilung kann anschließend analytisch auf die Verbundspannungsverteilung rückgerechnet werden. Abschließend wird ein Vergleich mit dem gängigen Ansatz einer konstanten Verbundspannung untersucht.
Superparamagnetic iron oxide nanoparticles as the sole method for sentinel node biopsy detection in patients with breast cancer
Authors: Karakatsanis A , Daskalakis K , Stålberg P , Olofsson H , Andersson Y , Eriksson S , Bergkvist L , Wärnberg F 
Published: September 2017

Abstract

Background
Sentinel node biopsy (SNB) using superparamagnetic iron oxide (SPIO) nanoparticles is a novel method in breast cancer. Several studies have verified the non-inferiority of SPIO compared with the standard use of radioisotope 99mTc with or without blue dye. The aim of the MONOS study presented here was to evaluate the use of SPIO as a sole tracer and the efficacy of tracer injection in the preoperative setting.

Methods
This prospective cohort study was carried out in two hospitals, one using 99mTc and the other SPIO. 99mTc was injected in the morning of the day of surgery or the day before. SPIO was either injected before surgery in the outpatient clinic or 1 h before the operation.

Results
A total of 338 consecutive patients with breast cancer underwent 343 procedures; SPIO nanoparticles were used in 184 procedures and 99mTc-labelled tracer in 159. Detection rates for SPIO and 99mTc were 95·6 and 96·9 per cent respectively (P = 0·537). All nodes with SPIO uptake were coloured brown. Fewer nodes were retrieved with SPIO (mean 1·35 versus 1·89), regardless of whether blue dye was used (P &lt; 0·001). Preoperative SPIO injection (58·7 per cent of procedures), a median of 16 (range 2–27) days before the procedure, was associated with a better tracer-specific detection rate (95·3 versus 86 per cent; P = 0·031) and retrieval of more nodes (mean 1·43 versus 1·03; P &lt; 0·001) than perioperative administration. Skin staining was present in 39·9 per cent of patients, and was related to breast-conserving surgery and periareolar injection.

Conclusion
The use of SPIO alone is a safe alternative, with results comparable to those of the standard dual technique using 99mTc and blue dye. The efficacy of injection in the preoperative setting simplifies logistics and improves performance. Skin staining can be prevented by a deeper peritumoral injection.
Euphorbia tirucalli β‐Amyrin Synthase: Critical Roles of Steric Sizes at Val483 and Met729 and the CH–π Interaction between Val483 and Trp534 for Catalytic Action
Authors: Hoshino Tsutomu , Nakagawa Kazuya , Aiba Yukari , Itoh Daichi , Nakada Chika , Masukawa Yukari 
Published: September 2017

AbstractThe functions of Val483, Trp534, and Met729 in Euphorbia tirucalli β‐amyrin synthase were revealed by comparing the enzyme activities of site‐directed mutants against that of the wild type. The Gly and Ala variants with a smaller bulk size at position 483 predominantly afforded monocyclic camelliol C, which suggested that the orientation of the (3S)‐2,3‐oxidosqualene substrate was not appropriately arranged in the reaction cavity as a result of the decreased bulk size, leading to failure of its normal folding into the chair–chair–chair–boat–boat conformation. The Ile variant, with a somewhat larger bulk, afforded β‐amyrin as the dominant product. Intriguingly, various variants of Trp534 exhibited significantly decreased enzymatic activities and provided no aberrantly cyclized products, although the aromatic Phe and Tyr residues were incorporated and the steric sizes of the aliphatic residues were altered. Therefore, the Trp534 residue does not stabilize the transient cation through a cation–π interaction. Furthermore, the Trp residue, with the largest steric bulk among all natural amino acids, is essential for high enzymatic activity. Robust CH–π complexation between the Val483 and Trp534 residues is proposed herein. Altering the steric bulk at the Met729 position afforded the pentacyclic skeletons. Thus, Met729 is positioned at the E‐ring formation site. More detailed insights into the functions of the Val483, Trp534, and Met729 residues are provided by homology modeling.
Overcoming the Incompatibility Challenge in Chemoenzymatic and Multi‐Catalytic Cascade Reactions
Authors: Schmidt Sandy , Castiglione Kathrin , Kourist Robert 
Published: September 2017

AbstractMulti‐catalytic cascade reactions bear a great potential to minimize downstream and purification steps, leading to a drastic reduction of the produced waste. In many examples, the compatibility of chemo‐ and biocatalytic steps could be easily achieved. Problems associated with the incompatibility of the catalysts and their reactions, however, are very frequent. Cascade‐like reactions can hardly occur in this way. One possible solution to combine, in principle, incompatible chemo‐ and biocatalytic reactions is the defined control of the microenvironment by compartmentalization or scaffolding. Current methods for the control of the microenvironment of biocatalysts go far beyond classical enzyme immobilization and are thus believed to be very promising tools to overcome incompatibility issues and to facilitate the synthetic application of cascade reactions. In this Minireview, we will summarize recent synthetic examples of (chemo)enzymatic cascade reactions and outline promising methods for their spatial control either by using bio‐derived or synthetic systems.
A Newly Designed Composite Gel Polymer Electrolyte Based on Poly(Vinylidene Fluoride‐Hexafluoropropylene) (PVDF‐HFP) for Enhanced Solid‐State Lithium‐Sulfur Batteries
Authors: Xia Yan , Wang Xiuli , Xia Xinhui , Xu Ruochen , Zhang Shengzhao , Wu Jianbo , Liang Yanfei , Gu Changdong , Tu Jiangping 
Published: September 2017

AbstractDeveloping high‐performance solid‐state electrolytes is crucial for the innovation of next‐generation lithium‐sulfur batteries. Herein, a facile method for preparation of a novel gel polymer electrolyte (GPE) based on poly(vinylidene fluoride‐hexafluoropropylene) (PVDF‐HFP) is reported. Furthermore, Li1.5Al0.5Ti1.5(PO4)3 (LATP) nanoparticles as the active fillers are uniformly embedded into the GPE to form the final PVDF‐HFP/LATP composite gel polymer electrolyte (CPE). Impressively, the obtained CPE demonstrates a high lithium ion transference number of 0.51 and improved electrochemical stability as compared to commercial liquid electrolyte. In addition, the assembled solid‐sate Li−S battery with the composite gel polymer electrolyte membrane presents a high initial capacity of 918 mAh g−1 at 0.05 C, and better cycle performance than the counterparts with liquid electrolyte. Our designed PVDF‐HFP/LATP composite can be a promising electrolyte for next‐generation solid‐state batteries with high cycling stability.