bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the Diurnal Variation of the Global Electric Circuit Obtained From Different Numerical Models
Authors: Jánský Jaroslav , Lucas Greg M. , Kalb Christina , Bayona Victor , Peterson Michael J. , Deierling Wiebke , Flyer Natasha , Pasko Victor P.
Published: November 2017

This work analyzes different current source and conductivity parameterizations and their influence on the diurnal variation of the global electric circuit (GEC). The diurnal variations of the current source parameterizations obtained using electric field and conductivity measurements from plane overflights combined with global Tropical Rainfall Measuring Mission satellite data give generally good agreement with measured diurnal variation of the electric field at Vostok, Antarctica, where reference experimental measurements are performed. An approach employing 85 GHz passive microwave observations to infer currents within the GEC is compared and shows the best agreement in amplitude and phase with experimental measurements. To study the conductivity influence, GEC models solving the continuity equation in 3‐D are used to calculate atmospheric resistance using yearly averaged conductivity obtained from the global circulation model Community Earth System Model (CESM). Then, using current source parameterization combining mean currents and global counts of electrified clouds, if the exponential conductivity is substituted by the conductivity from CESM, the peak to peak diurnal variation of the ionospheric potential of the GEC decreases from 24% to 20%. The main reason for the change is the presence of clouds while effects of 222Rn ionization, aerosols, and topography are less pronounced. The simulated peak to peak diurnal variation of the electric field at Vostok is increased from 15% to 18% from the diurnal variation of the global current in the GEC if conductivity from CESM is used.
The Impact of Nonequilibrium and Equilibrium Fractionation on Two Different Deuterium Excess Definitions
Authors: Dütsch Marina , Pfahl Stephan , Sodemann Harald
Published: November 2017

The deuterium excess (d) is a useful measure for nonequilibrium effects of isotopic fractionation and can therefore provide information about the meteorological conditions in evaporation regions or during ice cloud formation. In addition to nonequilibrium fractionation, two other effects can change d during phase transitions. The first is the dependence of the equilibrium fractionation factors on temperature, and the second is the nonlinearity of the δ scale on which d is defined. The second effect can be avoided by using an alternative definition that is based on the logarithmic scale. However, in this case d is not conserved when air parcels mix, which can lead to changes without phase transitions. Here we provide a systematic analysis of the benefits and limitations of both deuterium excess definitions by separately quantifying the impact of the nonequilibrium effect, the temperature effect, the δ‐scale effect, and the mixing effect in a simple Rayleigh model simulating the isotopic composition of air parcels during moist adiabatic ascent. The δ‐scale effect is important in depleted air parcels, for which it can change the sign of the traditional deuterium excess in the remaining vapor from negative to positive. The alternative definition mainly reflects the nonequilibrium and temperature effect, while the mixing effect is about 2 orders of magnitude smaller. Thus, the alternative deuterium excess definition appears to be a more accurate measure for nonequilibrium effects in situations where moisture is depleted and the δ‐scale effect is large, for instance, at high latitudes or altitudes.
Estimating Global Ecosystem Isohydry/Anisohydry Using Active and Passive Microwave Satellite Data
Authors: Li Yan , Guan Kaiyu , Gentine Pierre , Konings Alexandra G. , Meinzer Frederick C. , Kimball John S. , Xu Xiangtao , Anderegg William R. L. , McDowell Nate G. , Martinez‐Vilalta Jordi , Long David G. , Good Stephen P.
Published: November 2017

The concept of isohydry/anisohydry describes the degree to which plants regulate their water status, operating from isohydric with strict regulation to anisohydric with less regulation. Though some species level measures of isohydry/anisohydry exist at a few locations, ecosystem‐scale information is still largely unavailable. In this study, we use diurnal observations from active (Ku‐Band backscatter from QuikSCAT) and passive (X‐band vegetation optical depth (VOD) from Advanced Microwave Scanning Radiometer on EOS Aqua) microwave satellite data to estimate global ecosystem isohydry/anisohydry. Here diurnal observations from both satellites approximate predawn and midday plant canopy water contents, which are used to estimate isohydry/anisohydry. The two independent estimates from radar backscatter and VOD show reasonable agreement at low and middle latitudes but diverge at high latitudes. Grasslands, croplands, wetlands, and open shrublands are more anisohydric, whereas evergreen broadleaf and deciduous broadleaf forests are more isohydric. The direct validation with upscaled in situ species isohydry/anisohydry estimates indicates that the VOD‐based estimates have much better agreement than the backscatter‐based estimates. The indirect validation with prior knowledge suggests that both estimates are generally consistent in that vegetation water status of anisohydric ecosystems more closely tracks environmental fluctuations of water availability and demand than their isohydric counterparts. However, uncertainties still exist in the isohydry/anisohydry estimate, primarily arising from the remote sensing data and, to a lesser extent, from the methodology. The comprehensive assessment in this study can help us better understand the robustness, limitation, and uncertainties of the satellite‐derived isohydry/anisohydry estimates. The ecosystem isohydry/anisohydry has the potential to reveal new insights into spatiotemporal ecosystem response to droughts.
Partially Ordered Sets
Authors: Fattore Marco
Published: November 2017

A partially ordered set is a set endowed with an ordering criterion, which is in general not complete, that is, such that some pairs of elements of the set cannot be ordered or compared. Partially ordered sets are the natural setting for the description and the analysis of multidimensional systems of indicators, particularly, but not exclusively, when they are of an ordinal kind. They can be used in evaluation studies, for the computation of non‐aggregative synthetic indicators, for the definition of rankings, in cluster analysis, and in many other data analysis tasks. As the availability of complex ordinal data sets and multidimensional indicator systems is increasing, partially ordered sets are becoming a key tool for applied statistics, particularly in socio‐economics, environmental and ecological studies, and multicriteria decision‐making. Their use may involve heavy computations, but effective algorithms and software resources exist that make them a very useful tool in many concrete problems.
The Control of Flowering: Do Genetical and Physiological Approaches Converge?
Authors: Périlleux Claire , Bernier Georges
Published: November 2017

The sections in this article are

Introduction

Floral Meristem Identity Genes

Floral Repression Genes and Pathway

Floral Promotion Genes and Pathways

Interactions between Different Genes and Pathways: Welcome to Complexity

Conclusions

Acknowledgements
Endosperm Development
Authors: Brown Roy C. , Lemmon Betty E. , Nguyen Hong
Published: November 2017

The sections in this article are

Introduction

Background

Nuclear Endosperm Development

Differentiation

Acknowledgments
The Central Role of the Ovule in Apomixis and Parthenocarpy
Authors: Koltunow Anna M. , Vivian‐Smith Adam , Tucker Matthew R. , Paech Nicholas
Published: November 2017

The sections in this article are

Introduction

Development of Floral, Seed and Fruit Structures

Evolutionary Origin of Ovules, Seeds and Fruits

Plant Hormones Facilitate Long‐Range Communication within and between Floral Organs during Fruit and Seed Initiation

Apomixis—A Seed by Any Means?

Parthenocarpic Fruit Development and the Analysis of Fruit Initiation

Conclusions
Signaling by Protein Phosphorylation in Cell Division
Authors: Sasabe Michiko , Machida Yasunori
Published: November 2017

Regulation of cell division in eukaryotes including higher plants is crucial for growth, differentiation, development, and cell death. Protein phosphorylation plays a major role in signaling to control the cell division, and is driven by protein kinases called mitotic kinases, including a cyclin‐dependent kinase (CDK), an Aurora kinase, and a mitogen‐activated protein kinase (MAPK). In contrast to animals and yeast, our knowledge on the regulatory mechanism of the cell division in plants is very limited. Although plant cells seem to share some basic processes during the cell cycle progression with animal and yeast cells, they have acquired unique molecules orchestrating the cell division, reflecting the plant‐specific fashion in cell division such as cytokinesis. This chapter focuses on recent advances in the understanding of signaling molecules, so‐called mitotic kinases (CDKs, Auroras, MAPKs) during mitosis and cytokinesis in plant cells.
Induced Resistance – Orchestrating Defence Mechanisms through Crosstalk and Priming
Authors: van der Ent Sjoerd , Koornneef Annemart , Ton Jurriaan , Pieterse Corné M.J.
Published: November 2017

In nature, plants interact with a wide range of microbial pathogens and herbivorous insects. During the evolutionary arms race between plants and their attackers, primary and secondary immune responses evolved to recognise common or highly specialised features of the attacker encountered, resulting in sophisticated mechanisms of induced defence. Induced resistance mechanisms are characterised by a broad‐spectrum effectiveness and often act systemically in plant parts distant from the site of primary attack, thereby protecting the plant against subsequent invaders. Plant hormones are key players in the regulation of the defence signalling pathways involved. Because induced defence responses entail ecological fitness costs, plants must possess elaborate regulatory mechanisms that efficiently coordinate the activation of attacker‐specific defences so that fitness costs are minimised while optimal resistance is attained. A major focus in plant defence signalling research is to uncover key mechanisms by which plants tailor their responses to different attackers, and to investigate how plants cope with simultaneous interactions with multiple aggressors. Pathway crosstalk and priming for enhanced defence emerged as important regulatory mechanisms that enhance the efficiency of the plant's inducible defence arsenal. Here, we review the current knowledge on the signalling cascades involved in different types of induced pathogen and insect resistance, and the regulatory mechanisms by which plants are able to orchestrate their inducible defences in a cost‐effective manner.
Clarion call for histopathological clot analysis in “cryptogenic” ischemic stroke: implications for diagnosis and treatment
Authors: Bhaskar Sonu , Cordato Dennis , Cappelen‐Smith Cecilia , Cheung Andrew , Ledingham David , Celermajer David , Levi Christopher
Published: November 2017

Diagnosis, treatment, and secondary management of cryptogenic stroke patients pose a formidable challenge. The scenario is further complicated in patients with native and prosthetic valvular heart disease. We present a case study of a 36‐year‐old man who received intravenous thrombolysis (IV‐tPA) and endovascular thrombectomy (EVT) for presumed “cryptogenic” complete middle cerebral artery infarction who made a surprisingly excellent clinical recovery despite poor baseline and postintervention neuroimaging. Retrospective gram stain of his clot confirmed a diagnosis of infective endocarditis. This raises an important issue regarding need for more routine histopathological analysis of clot retrieved after EVT in “cryptogenic” stroke patients particularly those with valvular heart disease.
Electromagnetic Shielding Hybrid Nanogenerator for Health Monitoring and Protection
Authors: Zhang Qian , Liang Qijie , Zhang Zheng , Kang Zhuo , Liao Qingliang , Ding Yi , Ma Mingyuan , Gao Fangfang , Zhao Xuan , Zhang Yue
Published: November 2017

Nowadays, mankind faces increasingly energy crisis and electromagnetic radiation pollution. An energy harvester with function of protecting human health from electromagnetic radiation is a desirable solution to this problem. Here, a stretchable electromagnetic shielding hybrid nanogenerator (ES‐HNG) is reported which can not only scavenge thermal and mechanical energy from living environment but also protect and monitor human health. The ES‐HNG is capable of transforming mechanical and thermal energy to electricity based on triboelectric, piezoelectric, and pyroelectric effects. To be devised as a computer keyboard cover, ES‐HNG takes about 200 s to charge a capacitor to 3 V by typing. The stored energy can drive the portable devices successfully. Besides, the ES‐HNG eliminates electromagnetic radiation of computer completely due to its unique electromagnetic shielding property. A large range of electromagnetic wave (frequency is between 0 and 1.5 GHz) is shielded more than 99.9978% by the ES‐HNG. Moreover, the ES‐HNG is able to monitor human health by attaching it on human abdomen to be a self‐powered sensor. This work opens up a new prospect of harvesting energy effectively as well as protecting/monitoring human health from electromagnetic radiation surroundings.
Flexible Graphene Solution‐Gated Field‐Effect Transistors: Efficient Transducers for Micro‐Electrocorticography
Authors: Hébert Clement , Masvidal‐Codina Eduard , Suarez‐Perez Alejandro , Calia Andrea Bonaccini , Piret Gaelle , Garcia‐Cortadella Ramon , Illa Xavi , Del Corro Garcia Elena , De la Cruz Sanchez Jose M. , Casals Damia Viana , Prats‐Alfonso Elisabet , Bousquet Jessica , Godignon Philippe , Yvert Blaise , Villa Rosa , Sanchez‐Vives Maria V. , Guimerà‐Brunet Anton , Garrido Jose A.
Published: November 2017

Brain–computer interfaces and neural prostheses based on the detection of electrocorticography (ECoG) signals are rapidly growing fields of research. Several technologies are currently competing to be the first to reach the market; however, none of them fulfill yet all the requirements of the ideal interface with neurons. Thanks to its biocompatibility, low dimensionality, mechanical flexibility, and electronic properties, graphene is one of the most promising material candidates for neural interfacing. After discussing the operation of graphene solution‐gated field‐effect transistors (SGFET) and characterizing their performance in saline solution, it is reported here that this technology is suitable for μ‐ECoG recordings through studies of spontaneous slow‐wave activity, sensory‐evoked responses on the visual and auditory cortices, and synchronous activity in a rat model of epilepsy. An in‐depth comparison of the signal‐to‐noise ratio of graphene SGFETs with that of platinum black electrodes confirms that graphene SGFET technology is approaching the performance of state‐of‐the art neural technologies.
The Salt Matters: Enhanced Reversibility of Li–O2 Batteries with a Li[(CF3SO2)(n‐C4F9SO2)N]‐Based Electrolyte
Authors: Tong Bo , Huang Jun , Zhou Zhibin , Peng Zhangquan
Published: November 2017

The safety hazards and cycle instability of lithium metal anodes (LMA) constitute significant barriers to progress in lithium metal batteries. This situation is worse in Li–O2 batteries because the LMA is prone to be chemically attacked by O2 shuttled from the cathode. Notwithstanding, efforts on LMA are much sparse than those on the cathode in the realm of Li–O2 batteries. Here, a novel lithium salt of Li[(CF3SO2)(n‐C4F9SO2)N] (LiTNFSI) is reported, which can effectively suppress the parasitic side reactions and dendrite growth of LMA during cycling and thereby significantly enhance the overall reversibility of Li–O2 batteries. A variety of advanced research tools are employed to scrutinize the working principles of the LiTNFSI salt. It is revealed that a stable, uniform, and O2‐resistive solid electrolyte interphase is formed on LMA, and hence the “cross‐talk” between the LMA and O2 shuttled from the cathode is remarkably inhibited in LiTNFSI‐based Li–O2 batteries.
Superior Toughness and Fast Self‐Healing at Room Temperature Engineered by Transparent Elastomers
Authors: Kim Seon‐Mi , Jeon Hyeonyeol , Shin Sung‐Ho , Park Seul‐A , Jegal Jonggeon , Hwang Sung Yeon , Oh Dongyeop X. , Park Jeyoung
Published: November 2017

The most important properties of self‐healing polymers are efficient recovery at room temperature and prolonged durability. However, these two characteristics are contradictory, making it difficult to optimize them simultaneously. Herein, a transparent and easily processable thermoplastic polyurethane (TPU) with the highest reported tensile strength and toughness (6.8 MPa and 26.9 MJ m−3, respectively) is prepared. This TPU is superior to reported contemporary room‐temperature self‐healable materials and conveniently heals within 2 h through facile aromatic disulfide metathesis engineered by hard segment embedded aromatic disulfides. After the TPU film is cut in half and respliced, the mechanical properties recover to more than 75% of those of the virgin sample within 2 h. Hard segments with an asymmetric alicyclic structure are more effective than those with symmetric alicyclic, linear aliphatic, and aromatic structures. An asymmetric structure provides the optimal metathesis efficiency for the embedded aromatic disulfide while preserving the remarkable mechanical properties of TPU, as indicated by rheological and surface investigations. The demonstration of a scratch‐detecting electrical sensor coated on a tough TPU film capable of auto‐repair at room temperature suggests that this film has potential applications in the wearable electronics industry.
Pure Organic Emitter with Simultaneous Thermally Activated Delayed Fluorescence and Room‐Temperature Phosphorescence: Thermal‐Controlled Triplet Recycling Channels
Authors: Yu Ling , Wu Zhongbin , Zhong Cheng , Xie Guohua , Zhu Zece , Ma Dongge , Yang Chuluo
Published: November 2017

A new route to utilize the triplet excitons by simultaneous thermally activated delayed fluorescence (TADF) and phosphorescence is demonstrated for a new quinoxaline/phenoxazine hybrid emitter. Moreover, the two triplet recycling channels are thermally controlled, and a clear threshold temperature of 170 K is observed. Below the threshold temperature, direct triplet radiation (phosphorescence) is the dominant process. In contrast, the channel of upconversion through intersystem crossing is activated above the threshold and the resulting TADF gradually becomes the predominant process. By using the new compound as emitter in organic light‐emitting diodes, a high external quantum efficiency of 16.8% is far beyond the theoretical limit of the traditional fluorescent emitters.
Difluorobenzoxadiazole‐Based Polymer Semiconductors for High‐Performance Organic Thin‐Film Transistors with Tunable Charge Carrier Polarity
Authors: Shi Shengbin , Wang Yuxi , Uddin Mohammad Afsar , Zhou Xin , Guo Han , Liao Qiaogan , Zhu Xucheng , Cheng Xing , Woo Han Young , Guo Xugang
Published: November 2017

A series of difluorobenzoxadiazole‐based copolymers are synthesized for applications in high‐performance organic thin‐film transistors. Four π‐spacers with distinct electrical properties, bithiophene, difluorobithiophene, 2‐thiophene‐2′‐thiazole, and bithiazole, are inserted between head‐to‐head linkage containing bithiophene to promote polymer chain packing. Among the series, polymer containing bithiophene exhibits a unipolar p‐channel performance with a substantial hole mobility of 2.92 cm2 V−1 s−1, and minor structural modification leads to polymer containing bithiazole showing a remarkable unipolar n‐channel performance with an electron mobility of 0.83 cm2 V−1 s−1. Through a simple structural modification, such a drastic charge carrier polarity change without sacrificing mobility is elusive in organic thin‐film transistor field. Polymer containing hybrid 2‐thiophene‐2′‐thiazole spacer exhibits ambipolarity with encouraging hole/electron mobility of 0.27/0.35 cm2 V−1 s−1, and polymer containing difluorobithiophene shows an average hole mobility of 0.53 cm2 V−1 s−1. Among the results, p‐channel transistors exhibit encouraging device stability. The results demonstrate that difluorobenzoxadiazole is a versatile building block for enabling high‐mobility semiconductors with variable charge carrier polarity. X‐ray diffraction reveals that all difluorobenzoxadiazole‐based polymers have substantial film crystallinity with close π‐stacking and varied polymer chain orientation. The structure–property–device performance correlations from this study offer useful insights for materials innovation in organic thin‐film transistors.
Nanoscale Bipolar Electrical Switching of Ge2Sb2Te5 Phase‐Change Material Thin Films
Authors: Sun Xinxing , Roß Ulrich , Gerlach Jürgen W. , Lotnyk Andriy , Rauschenbach Bernd
Published: November 2017

Chalcogenide phase‐change materials (PCMs) exhibit distinct rapid changes in electrical properties upon repeatable switching between amorphous and crystalline structure and are thus attractive for emerging nonvolatile memory (phase‐change random access memory, PCRAM) applications. However, one of the key limitations of PCRAM concepts is their power consumption due to high RESET current requirement. In this work, the electrical memory switching behavior of Ge2Sb2Te5 phase‐change thin films is investigated in detail. Bipolar electrical switching of PCMs at the nanoscale is demonstrated by use of conductive atomic force microscopy and visualized by simultaneously recording topography and electric current maps. The memory cell exhibits excellent scalability (≈15 nm lateral size), low RESET/SET operation voltages (0.5 V), and high on/off resistance ratios (≈5 × 103) with a data storage density higher than 0.7 Tbit in.−2. The physical switching mechanism of the memory is explored by investigation of the local conduction channel, evaluating the local microstructure and local chemical composition by advanced electron microscopy. The switching process is interpreted as a combination of both phase‐change and electrolytic mechanisms.
Copper‐Catalyzed Alkylation of Thiophenols with Benzyltrimethylammonium Triflates
Authors: Lu Fangling , Chen Ziyue , Li Zhen , Wang Xiaoyan , Peng Xinyue , Li Cong , Li Ru , Pei Hongqiao , Wang Huamin , Gao Meng
Published: November 2017

A copper‐catalyzed cross coupling of thiophenols with benzyltrimethylammonium triflates has been developed. Various kinds of aryl and heteroaryl thiophenols and alkylthiols demonstrated to be efficient substrates, generating the desired alkyl thioethers in moderate to good yields. Meanwhile, different benzyltrimethylammonium triflates could be well tolerated.
Breastfeeding, weaning, and dietary practices during the Western Zhou Dynasty (1122–771 BC) at Boyangcheng, Anhui Province, China
Authors: Xia Yang , Zhang Jinglei , Yu Fei , Zhang Hui , Wang Tingting , Hu Yaowu , Fuller Benjamin T.
Published: November 2017

Objectives

Here we investigate breastfeeding and weaning practices and adult dietary habits at the Western Zhou Dynasty (1122–771 BC) site of Boyangcheng (薄阳城) located in Anhui Province, China. In addition, we utilize the differences in bone collagen turnover rates between rib and long bones from the same individual to examine past life histories, such as changes in diet or residence.

Materials and methods

Bone collagen from both the rib and long bones (either femora or humeri) of 42 individuals was measured for stable isotope ratios of carbon (δ13C) and nitrogen (δ15N). In addition, δ13C and δ15N values are reported for 35 animals (dogs, cows, horses, pigs, and deer).

Results

The human δ13C values range from −20.7‰ to −12.0‰ with a mean value of −18.8 ± 1.6‰. The human δ15N values range from 9.1‰ to 13.4‰ with a mean value of 10.9 ± 1.0‰. The animals display a wide range of δ13C (−21.5‰ to −8.2‰; −15.8 ± 4.5‰) and δ15N values (4.0‰ to 9.5‰; 6.5 ± 1.8‰).

Conclusions

The adult δ13C and δ15N results indicate that mixed C3 (rice) and C4 (millet) terrestrial diets with varying levels of animal protein (mostly pigs and deer) were consumed. The elevated subadult δ15N results return to adult levels by approximately 3–4 years of age, indicating that the weaning process was completed during this period. Individuals between 2 and 10 years old, with lower δ13C and δ15N results than the adult mean, possibly consumed more plant‐based diets, and this is consistent with Chinese medical teachings ∼1500 years later during the Tang Dynasty (AD 618–907). The isotopic offsets between the ribs and long bones revealed that five adults experienced dramatic dietary shifts in their later lives, switching from predominately C3/C4 to C3 diets. This research provides the first isotopic information about ancient Chinese breastfeeding and weaning practices and establishes a foundation for future studies to examine diachronic trends.
TeV‐ and MeV‐Physics Out of an Model
Authors: Neves Mario Junior , Helaÿel‐Neto Jose A.
Published: November 2017

The standard electroweak interaction is here re‐assessed to accommodate two different situations in Particle Physics. The first one is a ‐model at the TeV‐scale physics. The second one tackles the recent discussion of a possible fifth force mediated by a 17‐MeV X‐boson associated with an electron‐positron emission in the transition of an excited 8‐Beryllium to its ground state. The anomaly‐free model that provides these two scenarios is based on an ‐symmetry. It yields a new massive neutral boson, an exotic massive neutral fermion, right‐neutrinos and an additional neutral Higgs particle, which stems from a supplementary Higgs field, introduced along with the usual Higgs doublet responsible for the electroweak breaking and the masses of and Z0. Yukawa interactions of the two scalars generate the masses of the Standard Model leptons, neutrinos and a new exotic fermion of the model. The vacuum expectation values of the Higgses fix up two independent energy scales. One of them is the well‐confirmed electroweak scale, 246 GeV, whereas the other one is set up by adopting an experimental estimate for the ‐mass.
Coalescence of Cluster Beam Generated Sub‐2 nm Bare Au Nanoparticles and Analysis of Au Film Growth Parameters
Authors: Verrelli Emanuele , Michelakaki Irini , Boukos Nikos , Kyriakou Georgios , Tsoukalas Dimitris
Published: November 2017

In this work is presented the growth model for Au films grown on a carbon substrate at room temperature by using as building blocks Au nanoparticles (NPs) with 1.4 nm mean size generated via remote cluster beam synthesis and soft landing on the substrate. The key results highlighted in this work are that 1) the deposited nanoparticles coalesce at substrate level in such a way that the film growth is 3D, 2) newly formed nanoparticles at substrate level are predominantly magic number clusters and 3) coalescensce takes place as soon as two neighboring nanopartciles come closer than a critical distance. The film growth was investigated by TEM as a function of Au load, in the range 0–1.2 μg/cm2. Two distinct regimes are identified: the “landing regime” and the “coalescence regime”. During the latter the film growth is 3D with a dynamic scaling exponent z of 2.13. Particular attention was devoted to the study of the evolution of the NP population from the moment they are generated with the cluster beam generator to the moment they land on the substrate and coalesce with other NPs. Our results show that 1) the NPs generated by the cluster beam are heterogeneous in size and are made by more than 95% by Au Magic numbers, mainly Au20 and Au55 and 2) kinetic processes (coalescence) at substrate level is capable of producing NPs populations made of larger Au magic numbers containing up to several thousands of Au atoms. Experimental and simulation results provide insight into the coalescence mechanism and provide strong evidence that the NPs coalesce when the nearest neighbor distance is below a critical mark. The critical distance is at its minimum 0.4‐0.5 nm and it is still unclear whether it is constant or not although the best matching simulation results seem to point to a superlinear dependence from the NP size difference between two neighboring candidate coalescing NPs. The coalescence phenomenon investigated in this work pinpoints the unique self‐organization properties of these small Au NPs in creating films with a stable edge‐to‐edge mean nearest neighbor distance of the order of 1.4 nm.
Columnar Liquid Crystals from a Giant Macrocycle Mesogen
Authors: Kawano Shin‐ichiro , Kato Masahiro , Soumiya Shinya , Nakaya Masato , Onoe Jun , Tanaka Kentaro
Published: November 2017

Columnar liquid crystals composed of a giant macrocyclic mesogen were prepared. The giant macrocyclic mesogen has a square hollow with a 2.5 nm diagonal, which was bounded by diindolo[3,2‐b:2′,3′‐h]carbazole (diindolocarbazole) moieties as the edges and bis(salicylidene)‐o‐phenylenediamine (salphen) moieties as the corners. The shape and size of the macrocycle were directly observed by scanning tunneling microscopy (STM). Each side of the bright square in the STM image corresponds to a diindolocarbazole moiety, and the length of the sides was consistent with the result of the single crystal analysis of diindolocarbazole. Finally, we successfully obtained a giant macrocycle with long and branched side chains, which exhibited a rectangular columnar LC phase over a wide temperature range. To the best of our knowledge, it contained the largest discrete inner space of any thermotropic columnar liquid crystal composed of macrocyclic mesogens.
Fluorinated Vinylsilanes from the Copper‐Catalyzed Defluorosilylation of Fluoroalkene Feedstocks
Authors: Sakaguchi Hironobu , Ohashi Masato , Ogoshi Sensuke
Published: November 2017

Herein, a copper‐catalyzed C−F bond defluorosilylation reaction of tetrafluoroethylene and other polyfluoroalkenes is described. Mechanistic studies, based on a series of stoichiometric reactions with copper complexes, revealed that the key steps of this defluorosilylation reaction are 1) the 1,2‐addition of a silylcopper intermediate to the polyfluoroalkene and 2) a subsequent selective β‐fluorine elimination, which generates a Cu−F species. The β‐fluorine elimination is facilitated by Lewis acidic F−Bpin, which is generated in situ during the defluorosilylation.
Total Syntheses of the Monoterpenoid Indole Alkaloids (±)‐Alstoscholarisine B and C
Authors: Mason Jeremy D. , Weinreb Steven M.
Published: November 2017

Total syntheses of the monoterpenoid indole alkaloids (±)‐alstoscholarisine B and C were accomplished starting from a readily available indole‐2‐acetic ester and an α,β‐unsaturated N‐sulfonyllactam.
Rational Optimization of Tumor Suppressor‐Derived Peptide Inhibitor Selectivity between Oncogene Tyrosine Kinases ErbB1 and ErbB2
Authors: Deng Yilin , Li Jian
Published: November 2017

The tumor‐suppressor protein Mig‐6 has been found to directly target and inhibit the human ErbB receptor tyrosine kinases ErbB1 and ErbB2. Despite their highly homologous nature, these two kinases are separately involved in the development of different types of human cancer. Here, we utilized a rational strategy to iteratively optimize the interaction specificity of the two kinases with a Mig‐6 derived peptide by exploiting structural diversity space. Instead of traditionally improving the peptide binding potency, the optimization attempts to maximize the affinity difference between peptides binding to ErbB1 and ErbB2. The computational design was also substantiated by using fluorescence‐based assays. Consequently, we successfully designed three peptides, HSLTPTQSF, THLMNLLRI, and NSGCPMHK, with high or moderate selectivity for ErbB1 over ErbB2 (3.1‐, 6.3‐, and 3.0‐fold, respectively) and two peptides, PCMTDFLFT and WVIFPSQTN, with moderate or modest selectivity for ErbB2 over ErbB1 (3.5‐ and 1.6‐fold, respectively). The method is expected to be used for the rational molecular design of selective peptide entities for other protein systems.
Design, Synthesis, Molecular Docking, and Anticancer Activity of Phthalazine Derivatives as VEGFR‐2 Inhibitors
Authors: El‐Helby Abdel‐Ghany A. , Ayyad Rezk R. A. , Sakr Helmy , El‐Adl Khaled , Ali Mamdouh M. , Khedr Fathalla
Published: November 2017

Novel series of phthalazine derivatives 6–11 were designed, synthesized, and evaluated for their anticancer activity against two human tumor cell lines, HCT‐116 human colon adenocarcinoma and MCF‐7 breast cancer cells, targeting the VEGFR‐2 enzyme. Compounds 7a,b and 8b,c showed the highest anticancer activities against both HCT116 human colon adenocarcinoma cells with IC50 of 6.04 ± 0.30, 13.22 ± 0.22, 18 ± 0.20, and 35 ± 0.45 μM, respectively, and MCF‐7 breast cancer cells with IC50 of 8.8 ± 0.45, 17.9 ± 0.50, 25.2 ± 0.55, and 44.3 ± 0.49 μM, respectively, in comparison to sorafenib as reference drug with IC50 of 5.47 ± 0.3 and 7.26 ± 0.3 μM, respectively. Eleven compounds in this series were further evaluated for their inhibitory activity against VEGFR‐2, where compounds 7a, 7b, 8c, and 8b also showed the highest VEGFR‐2 inhibition with IC50 of 0.11 ± 0.01, 0.31 ± 0.03, 0.72 ± 0.08, and 0.91 ± 0.08 μM, respectively, in comparison to sorafenib as reference ligand with IC50 of 0.1 ± 0.02. Furthermore, molecular docking studies were performed for all synthesized compounds to predict their binding pattern and affinity towards the VEGFR‐2 active site, in order to rationalize their anticancer activity in a qualitative way.
Effect of status epilepticus on expression of brain UDP‐glucuronosyltransferase 1a in rats
Authors: Asai Yuki , Tanaka Hatsuna , Nadai Masayuki , Katoh Miki
Published: November 2017

Status epilepticus (SE) involves severe epileptic seizures that cause oxidative stress in the brain. Oxidative stress is known to influence uridine 5'‐diposphate‐glucuronosyltransferase (UGT) 1A expression. The present study aimed at elucidating the effect of SE on Ugt1a1, Ugt1a6 and Ugt1a7 expression in the rat brain. Kainic acid was used to create an animal model of SE. Sprague‐Dawley rats were treated intraperitoneally with 10 mg/kg kainic acid. Ugt1a1 and Ugt1a7 mRNA levels were increased by SE in the cortex and hippocampus (Ugt1a1: 4.0‐ and 5.3‐fold, respectively; Ugt1a7: 2.8‐ and 2.5‐fold, respectively). Moreover, the induction degree of heme oxygenase‐1 mRNA, an oxidative stress marker, was high in these regions, suggesting that oxidative stress could be involved in Ugt1a1 and Ugt1a7 induction. Ugt1a6 was elevated by 1.8‐fold in the cortex in both SE and non‐response (non‐epileptic seizure response) rats, implying that Ugt1a6 induction may be independent from SE. An intraperitoneal single administration of 25 mg/kg diazepam (DZP) for the treatment of SE could attenuate heme oxygenase‐1 induction in the cortex, whereas Ugt1a1 was decreased in the hippocampus, but not in the cortex, suggesting that there likely exists an alternative mechanism for Ugt1a1 reduction by DZP treatment. Continuous 14‐day administration of DZP inhibited Ugt1a1 induction in the cortex, but did not have an effect on Ugt1a7 induction. This study indicated that SE altered the expression of brain Ugt1a1 and Ugt1a7, which could alter glucuronidation in the brain.
Displaying Tetra‐Membrane Spanning Claudins on Enveloped Virus‐Like Particles for Cancer Immunotherapy
Authors: Schneider Irene C. , Hartmann Jessica , Braun Gundula , Stitz Jörn , Klamp Thorsten , Bihi Mahjoub , Sahin Ugur , Buchholz Christian J.
Published: November 2017

Virus‐like particles (VLPs) displaying foreign antigens have become an important tool in vaccination including the induction of immune responses against self‐antigens. Claudin 6 (CLDN6) has been identified as tumor‐associated antigen and is therefore a potential target for tumor vaccination strategies. However, as tetra‐membrane spanning protein its incorporation into VLPs while preserving a native fold is challenging. Here, we attempted the incorporation of a panel of engineered CLDN6 variants into the membrane of retrovirus‐derived VLPs. Interestingly, wild‐type CLDN6 revealed the most efficient display. VLPs presenting CLDN6 or CLDN9 derived from different donor species were produced and preservation of their native confirmation was demonstrated by antibody binding assays. VLPs displaying murine CLDN6 were used to immunize mice. Antibodies recognizing native CLDN6 as displayed on cell surfaces and mediating complement‐dependent cytotoxicity were elicited in vaccinated animals. The data suggest applications of CLDN6 displaying VLPs in cancer immunotherapy.
Flexible and Accessible Automated Operation of Miniature Chromatography Columns on a Liquid Handling Station
Authors: Konstantinidis Spyridon , Goh Hai‐Yuan , Martin Bufájer José M. , de Galbert Paul , Parau Maria , Velayudhan Ajoy
Published: November 2017

The High Throughput (HT) investigation of chromatographic separations is an important element of downstream bioprocess development due to the importance of chromatography as a technique for achieving stringent regulatory requirements on product purity. Various HT formats for chromatography exist, but the miniature column approach has characteristics resembling large scale packed bed column chromatography the most. The operation of such columns on robotic stations can be automated, but this is not always a straightforward procedure; the robotic manipulations are highly dependent on the settings of each experiment and the standard commands of the supporting software may not provide readily the required flexibility and accessibility for “plug and play” functionality. These can limit the potential of this technique in laboratories engaging on HT activities. In this work, we present an application which aims to overcome this challenge by providing end‐users with a flexible operation of the miniature column technique on an automated liquid handler. The application includes a script which is written on Freedom EVOware, and is supplemented by custom compiled executables. Here, the manipulations carried out by the application are described in detail and its functionality is demonstrated through typical experiments based on bind and elute miniature column chromatography. The application is shown to allow for the unsupervised “on‐the‐fly” programming of the robotic station and to ultimately make the technique accessible to non‐automation experts. This application is therefore well suited to simplifying development activities based on the robotic deployment of the miniature column chromatography technique.
When Do Two‐Stage Processes Outperform One‐Stage Processes?
Authors: Klamt Steffen , Mahadevan Radhakrishnan , Hädicke Oliver
Published: November 2017

Apart from product yield and titer, volumetric productivity is a key performance indicator for many biotechnological processes. Due to the inherent trade‐off between the production of biomass as catalyst and of the actual target product, yield and volumetric productivity cannot be optimized simultaneously. Therefore, in combination with genetic techniques for dynamic regulation of metabolic fluxes, two‐stage fermentations (TSFs) with separated growth and production phase have recently gained much interest because of their potential to improve the productivity of bioprocesses while still allowing high product yields. However, despite some successful case studies, so far it has not been discussed and analyzed systematically whether or under which conditions a TSF guarantees superior productivity compared to one‐stage fermentation (OSF). In this study, we use mathematical models to demonstrate that the volumetric productivity of a TSF is not automatically better than of a corresponding OSF. Our analysis reveals that the sharp decrease of the specific substrate uptake rate usually observed in (non‐growth) production phases severely impacts the volumetric productivity and thus raises a big challenge for designing competitive TSF processes. We discuss possible approaches such as enforced ATP wasting to improve substrate utilization rates in the production phase by which TSF processes can become superior to OSF. We also analyze additional factors influencing the relative performance of OSF and TSF and show that OSF processes can be more appropriate if a high product yield is an economic constraint. In conclusion, a careful assessment of the trade‐offs between substrate uptake rates, yields, and productivity is necessary when deciding for OSF vs. TSF processes.
Highly active spore biocatalyst by self‐assembly of co‐expressed anchoring scaffoldin and multimeric enzyme
Authors: Chen Long , Holmes Megan , Schaefer Elise , Mulchandani Ashok , Ge Xin
Published: November 2017

We report a spore‐based biocatalysis platform capable of producing and self‐assembling active multimeric enzymes on a spore surface with a high loading density. This was achieved by co‐expressing both a spore surface‐anchoring scaffoldin protein containing multiple cohesin domains and a dockerin‐tagged enzyme of interest in the mother cell compartment during Bacillus subtilis sporulation. Using this method, tetrameric β‐galactosidase was successfully displayed on the spore surface with a loading density of 1.4 × 104 active enzymes per spore particle. The resulting spore biocatalysts exhibited high conversion rates of transgalactosylation in water/organic emulsions. With easy manufacture, enhanced thermostability, excellent reusability, and long‐term storage stability at ambient temperature, this approach holds a great potential in a wide range of biocatalysis applications especially involving organic phases.
Risk score to predict biliary leakage after elective liver resection
Authors: Mohkam K , Farges O , Vibert E , Soubrane O , Adam R , Pruvot F-R , Regimbeau J-M , Adham M , Boleslawski E , Mabrut J-Y , Ducerf C , Pradat P , Darnis B , Cazauran J-B , Lesurtel M , Dokmak S , Aussilhou B , Dondero F , Allard M-A , Ciacio O , Pittau G , Cherqui D , Castaing D , Sa Cunha A , Truant S , Hardwigsen J , Le Treut Y-P , Grégoire E , Scatton O , Brustia R , Sepulveda A , Cosse C , Laurent C , Adam J-P , El Bechwaty M , Perinel J
Published: November 2017

Background

Biliary leakage remains a major cause of morbidity after liver resection. Previous prognostic studies of posthepatectomy biliary leakage (PHBL) lacked power, population homogeneity, and model validation. The present study aimed to develop a risk score for predicting severe PHBL.

Methods

In this multicentre observational study, patients who underwent liver resection without hepaticojejunostomy in one of nine tertiary centres between 2012 and 2015 were randomly assigned to a development or validation cohort in a 2 : 1 ratio. A model predicting severe PHBL (International Study Group of Liver Surgery grade B/C) was developed and further validated.

Results

A total of 2218 procedures were included. PHBL of any severity and severe PHBL occurred in 141 (6·4 per cent) and 92 (4·1 per cent) patients respectively. In the development cohort (1475 patients), multivariable analysis identified blood loss of at least 500 ml, liver remnant ischaemia time 45 min or more, anatomical resection including segment VIII, transection along the right aspect of the left intersectional plane, and associating liver partition and portal vein ligation for staged hepatectomy as predictors of severe PHBL. A risk score (ranging from 0 to 5) was built using the development cohort (area under the receiver operating characteristic curve (AUROC) 0·79, 95 per cent c.i. 0·74 to 0·85) and tested successfully in the validation cohort (AUROC 0·70, 0·60 to 0·80). A score of at least 3 predicted an increase in severe PHBL (19·4 versus 2·6 per cent in the development cohort, P < 0·001; 15 versus 3·1 per cent in the validation cohort, P < 0·001).

Conclusion

The present risk score reliably predicts severe PHBL. It represents a multi-institutionally validated prognostic tool that can be used to identify a subset of patients at high risk of severe PHBL after elective hepatectomy.
Chromatographic analysis of VOC patterns in exhaled breath from smokers and nonsmokers
Authors: Capone Simonetta , Tufariello Maria , Forleo Angiola , Longo Valentina , Giampetruzzi Lucia , Radogna Antonio Vincenzo , Casino Flavio , Siciliano Pietro
Published: November 2017

Cigarette smoking harms nearly every organ of the body and causes many diseases. The analysis of exhaled breath for exogenous and endogenous volatile organic compounds (VOCs) can provide fundamental information on active smoking and insight into the health damage that smoke is creating. Various exhaled VOCs have been reported as typical of smoking habit and recent tobacco consumption, but to date, no eligible biomarkers have been identified. Aiming to identify such potential biomarkers, in this pilot study we analyzed the chemical patterns of exhaled breath from 26 volunteers divided into groups of nonsmokers and subgroups of smokers sampled at different periods of withdrawal from smoking. Solid‐phase microextraction technique and gas chromatography/mass spectrometry methods were applied. Many breath VOCs were identified and quantified in very low concentrations (ppbv range), but only a few (toluene, pyridine, pyrrole, benzene, 2‐butanone, 2‐pentanone and 1‐methyldecyclamine) were found to be statistically significant variables by Mann–Whitney test. In our analysis, we did not consider the predictive power of individual VOCs, as well as the criterion of uniqueness for biomarkers suggests, but we used the patterns of the only statistically significant compounds. Probit prediction model based on statistical relevant VOCs‐patterns showed that assessment of smoking status is heavily time dependent. In a two‐class classifier model, it is possible to predict with high specificity and sensitivity if a subject is a smoker who respected 1 hour of abstinence from smoking (short‐term exposure to tobacco) or a smoker (labelled "blank smoker") after a night out of smoking (long‐term exposure to tobacco). On the other side, in our study "blank smokers" are more like non‐smokers so that the two classes cannot be well distinguished and the corresponding prediction results showed a good sensitivity but low selectivity.
Sustainable Entrepreneurship Research: Taking Stock and looking ahead
Authors: Muñoz Pablo , Cohen Boyd
Published: November 2017

The recognition of entrepreneurship as a solution to, rather than a cause of, environmental degradation and social inequality moved the field to identify a new type of entrepreneurial activity, namely sustainable entrepreneurship. Scholarly interest has spiked in recent years; however, aside from its aspirational appeal, there remains a lack of understanding of the nature of the phenomenon and the future of sustainable entrepreneurship in theory and practice. This review seeks to provide a conceptual basis for stimulating scholarly thought and improving our collective understanding of sustainable entrepreneurship as a distinct subdomain within entrepreneurship research. Based on boundary definition and delineation of main features, this review critically discusses the main challenges ahead and elaborates on the research implications and future research directions beyond current, dominant approaches to entrepreneurial action. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment