bluuebunny/crossref_metadata_2025 huggingface dataset:
Tabu Search for the Vehicle Routing Problem with Multiple Trips, Time Windows, and Simultaneous Delivery-Pickup
Authors: Suprayogi Suprayogi , Priyandari Yusuf
Published: February 2018

This paper discusses a vehicle routing problem with multiple trips, time windows, and simultaneous delivery-pickup (VRPMTTWSDP). This problem is a variant of the basic vehicle routing problem (VRP) including the following characteristics: multiple trips, time windows, and simultaneous delivery-pickup.  In this paper, a solution approach based on tabu search (TS) is proposed. In the proposed TS, the sequential insertion (SI) algorithm is used to construct an initial solution. A neighbor structure is generated by applying an operator order consisting of eleven operators of relocation, exchange, and crossover operators. A tabu solution code (TSC) method is applied as a tabu restriction mechanism. Computational experiments are carried out to examine the performance of the proposed TS using hypothetical instances. The performance of the proposed TS is compared to the local search (LS) and the genetic algorithm (GA). The comparison shows that the proposed TS is better in terms of the objective function value.
Nitrogen Fixation in the Intertidal Sediments of the Yangtze Estuary: Occurrence and Environmental Implications
Authors: Hou Lijun , Wang Rong , Yin Guoyu , Liu Min , Zheng Yanling
Published: February 2018

Nitrogen fixation is a microbial‐mediated process converting atmospheric dinitrogen gas to biologically available ammonia or other molecules, and it plays an important role in regulating nitrogen budgets in coastal marine ecosystems. In this study, nitrogen fixation in the intertidal sediments of the Yangtze Estuary was investigated using nitrogen isotope tracing technique. The abundance of nitrogen fixation functional gene (nifH) was also quantified. The measured rates of sediment nitrogen fixation ranged from 0.37 to 7.91 nmol N g−1 hr−1, while the abundance of nifH gene varied from 2.28 × 106 to 1.28 × 108 copies g−1 in the study area. The benthic nitrogen fixation was correlated closely to the abundance of nifH gene and was affected significantly by salinity, pH, and availability of sediment organic carbon and ammonium. It is estimated that sediment nitrogen fixation contributed approximately 9.3% of the total terrigenous inorganic nitrogen transported annually into the Yangtze estuarine and coastal environment. This result implies that the occurrence of benthic nitrogen fixation acts as an important internal source of reactive nitrogen and to some extent exacerbates nitrogen pollution in this aquatic ecosystem.
No seasonality in cognitive performance among adolescents at a subarctic latitude (69°N)
Authors: Friborg Oddgeir , Sundby Jørgen , Rognmo Kamilla , Rosenvinge Jan H. , Bergvik Svein
Published: February 2018

Seasonal changes in daylight are substantial in subarctic areas and are known to affect circadian sleep rhythms. We examined whether seasonality in cognitive performance also exists and to what extent seasonality in sleep moderates this relationship. In the city of Tromsø (Norway) at 69°N, 182 adolescents (36% male; mean age 16.8 years) participated in a prospective study. The cognitive measures included verbal and visual memory, verbal learning, psychomotor speed, and problem solving, whereas sleep and sleep‐related problems were recorded via weekly sleep diaries and questionnaires. The results indicated no effect of season on any of the cognitive tests. Seasonality in sleep timing, insomnia, and fatigue were confirmed; however, these variables did not modify the null correlation between season and cognition. The lack of seasonality in cognition is a positive finding and serves to undermine myths about the burdens of living in subarctic areas with substantial seasonal changes in daylight.
The Corrosion Behavior of Mg5Y in Nominally Distilled Water
Authors: Cao Fuyong , Zheng Dajiang , Song Guang‐Ling , Shi Zhiming , Atrens Andrej
Published: February 2018

This paper studies the macro and micro corrosion of Mg5Y in nominally distilled water. The Y‐containing corrosion product film formed on the alloy surface provides some protection for the Mg matrix to the galvanic corrosion caused by Y‐containing second‐phase particles. In some cases, there is no corrosion of the matrix surrounding most of the second phase particles. However, about 2% of the second‐phase particles in the as‐cast Mg5Y causes micro‐galvanic corrosion, resulting in ‘bump’ or ‘volcano’ shaped corrosion product deposit. These ‘active particles’ cannot be significantly reduced by solution‐heat‐treatment.
A Novel Theranostic Nanoplatform Based on Pd@Pt‐PEG‐Ce6 for Enhanced Photodynamic Therapy by Modulating Tumor Hypoxia Microenvironment
Authors: Wei Jingping , Li Jingchao , Sun Duo , Li Qi , Ma Jinyuan , Chen Xiaolan , Zhu Xuan , Zheng Nanfeng
Published: February 2018

Photodynamic therapy (PDT), which utilizes reactive oxygen species to kill cancer cells, has found wide applications in cancer treatment. However, the hypoxic nature of most solid tumors can severely restrict the efficiency of PDT. Meanwhile, the hydrophobicity and limited tumor selectivity of some photosensitizers also reduce their PDT efficacy. Herein, a photosensitizer‐Pd@Pt nanosystem (Pd@Pt‐PEG‐Ce6) is designed for highly efficient PDT by overcoming these limitations. In the nanofabrication, Pd@Pt nanoplates, exhibiting catalase‐like activity to decompose H2O2 to generate oxygen, are first modified with bifunctional PEG (SH‐PEG‐NH2). Then the Pd@Pt‐PEG is further covalently conjugated with the photosensitizer chlorin e6 (Ce6) to get Pd@Pt‐PEG‐Ce6 nanocomposite. The Pd@Pt‐PEG‐Ce6 exhibits good biocompatibility, long blood circulation half‐life, efficient tumor accumulation, and outstanding imaging properties. Both in vitro and in vivo experimental results clearly indicate that Pd@Pt‐PEG‐Ce6 effectively delivers photosensitizers to cancer cells/tumor sites and triggers the decomposition of endogenous H2O2 to produce oxygen, resulting in a remarkably enhanced PDT efficacy. Moreover, the moderate photothermal effect of Pd@Pt nanoplates also strengthen the PDT of Pd@Pt‐PEG‐Ce6. Therefore, by integrating the merits of high tumor‐specific accumulation, hypoxia modulation function, and mild photothermal effect into a single nanoagent, Pd@Pt‐PEG‐Ce6 readily acts as an ideal nanotherapeutic platform for enhanced cancer PDT.
Rational Design of Nanostructured Functional Interlayer/Separator for Advanced Li–S Batteries
Authors: Jeong Yo Chan , Kim Jae Ho , Nam Seunghoon , Park Chong Rae , Yang Seung Jae
Published: February 2018

The lithium–sulfur (Li–S) battery is considered as a promising future energy storage device owing to its high theoretical energy density, low cost of the raw active material (sulfur), and its environmental friendliness. On the other hand, there are still challenging issues for the practical applications of Li–S batteries, including low sulfur utilization, poor cyclability, and rate capability. Although considerable efforts are made to overcome the current obstacles in Li–S batteries, one is still far from meeting the requirements for the commercialization of Li–S batteries. This review outlines the recent progress in Li–S batteries based on novel configurations, such as incorporating functional interlayers/separators beyond the approach for preparing novel cathodes, and discusses the role of the configuration in Li–S batteries. The functions of the newly introduced functional interlayer/separator are highlighted to address the problems of Li–S batteries. From classification of the functions, the perspectives and outlook are presented to rationally design a novel functional interlayer/separator for high‐performance Li–S batteries.
Hollow Structural Transition Metal Oxide for Advanced Supercapacitors
Authors: Wei Jilei , Li Xinran , Xue Huaiguo , Shao Jinying , Zhu Rongmei , Pang Huan
Published: February 2018

Electrochemical capacitors (supercapacitors, SCs), have been deemed to be one of the most promising powerful electrochemical energy storage devices, owing to that SCs have long cycle lives, high power densities, and fast recharge capabilities. Transition metal oxide is one of the most promising electrode materials in the application of SCs, but the poor active surface areas limit their electrochemical performances. Particularly, hollow structures can enhance their active surface areas and porosity for better transportation. In this review, the development regarding hollow structures of the metal oxide, metal oxide complex, and carbon–metal oxide complex is discussed. Furthermore, performances of these materials applied in SCs are tested in various systems, and their electrochemical performances are introduced and compared. The disadvantages of SCs based on hollow metal oxide materials are also discussed, and the various solutions are provided.
Viologen‐Hypercrosslinked Ionic Porous Polymer Films as Active Layers for Electronic and Energy Storage Devices
Authors: Wang Luxin , Ding Junjie , Sun Sai , Zhang Bin , Tian Xiangyu , Zhu Jinhui , Song Sannian , Liu Bo , Zhuang Xiaodong , Chen Yu
Published: February 2018

Over the past decades, numerous scientists have focused on designing complicated monomers, developing new synthesis protocols, and optimizing chemical structures for realizing high‐performance organic or polymer electronics and energy storage devices. However, much less attention has been paid to ionic‐ and radical‐rich porous organic films, which are essential components of aforementioned devices. In this study, an air‐stable, large‐area, free‐standing, and viologen‐linked ionic porous polymer (denoted as IPP‐V) film is developed in situ through electrochemical polymerization. This film is applied to a device by sandwiching it between indium tin oxide (ITO) and Au (i.e., ITO/IPP‐V/Au); the device exhibits a memristive behavior with an ON–OFF current ratio of ≈2. After the IPP‐V film is subjected to thermal pyrolysis at 500 °C, the as‐produced film (denoted as IPP‐V‐500) acts as an active material for an in‐plane micro‐supercapacitor and exhibits a high volumetric capacitance level of up to 4.44 F cm−3. This work not only offers a new and convenient strategy toward large‐area ionic porous polymer films for memristor, but also provides a new porous polymer derived carbon film for energy storage.
An Effective Strategy toward High‐Efficiency Fluorescent OLEDs by Radiative Coupling of Spatially Separated Electron–Hole Pairs
Authors: Li Binbin , Gan Lin , Cai Xinyi , Li Xiang‐Long , Wang Zhiheng , Gao Kuo , Chen Dongcheng , Cao Yong , Su Shi‐Jian
Published: February 2018

An effective strategy toward low‐driving voltage and high‐efficiency fluorescent organic light‐emitting diodes (OLEDs) by long‐range radiative coupling of spatially separated electron–hole pairs is proposed. Charge transfer excited states between p‐type hole‐transport layer and n‐type electron‐transport layer can be achieved although they are separated by an interlayer, giving significantly reduced efficiency roll‐off and higher luminance compared with the devices based on interface exciplex. Remarkable external quantum efficiency near 15% is also achieved by employing conventional red fluorescent dyes doped into the hole‐transport layer adjacent to the interlayer due to the avoidance of the direct carrier trapping and thus the generation of unwanted nonradiative triplet excitons. Different from the conventional devices with a host–guest structure for both exciton generation and energy releasing, such unique device concept provides a bright avenue toward structure‐simplified and high‐performance fluorescent OLEDs, where the long‐range coupled radiative excitons and the following energy releasing are separated in their own channels.
Graphene–Perovskite Schottky Barrier Solar Cells
Authors: Song Yi , Osherov Anna , Bulović Vladimir , Kong Jing
Published: February 2018

Perovskite solar cells have attained incredible power conversion efficiencies but it is still unclear whether photogenerated carriers are free or excitonic in nature. Originally, it is believed that they are exciton‐based devices, similar to organic or dye‐sensitized solar cells. However, the emergence of efficient planar devices as well as measurements of exciton binding energy in the range of 10–100 meV suggest that they may be free carrier‐based. In this work, the free carrier model is confirmed by building graphene/perovskite Schottky barrier solar cells, analogous to conventional metal/semiconductor Schottky barrier solar cells. To address the challenges of building such devices, solution‐processing techniques are extensively investigated for depositing perovskite films directly onto graphene in order to obtain an intimate contact between the graphene and perovskite. Interestingly, these graphene/perovskite Schottky barrier devices have reasonably good efficiency—up to 10.6%—and short circuit current densities only slightly lower than control devices. Furthermore, devices with neither a hole transport layer nor an electron transport layers have power conversion efficiencies of up to 6%. These results provide convincing evidence supporting the free carrier model for methylammonium lead iodide perovskites and offer insights on potential alternative designs for perovskite solar cells.
Validation study on spatially averaged two‐fluid model for gas–solid flows: I. A priori analysis of wall bounded flows
Authors: Schneiderbauer Simon
Published: February 2018

In our prior study (Schneiderbauer, AIChE J, 2017;63(8):3544–3562), we presented a spatially averaged two‐fluid model, where closure models for the unresolved terms were derived. These closures require constitutive relations for the turbulent kinetic energies (TKEs) of the gas and solids phase as well as for the sub‐filter variance of the solids volume fraction (VVF). In this study, we have performed highly resolved TFM simulations of a set of three‐dimensional wall dominated periodic channels. An a priori analysis shows that these closures are able to correctly predict the wall profiles of the sub‐grid drag modification, the TKEs, the turbulent viscosities and the VVF without requiring special wall corrections. Solely the mixing lengths, which is required by the closures, has to be adapted in the vicinity of wall similar to single‐phase turbulence; in particular, the minimum of the filter size and the distance to the wall should be used. © 2018 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1591–1605, 2018
A low‐cost ultrasound model for simulation of paediatric distal forearm fractures
Authors: Snelling Peter James
Published: February 2018

Background

Forearm injuries are a common presentation to the emergency department. Point‐of‐care ultrasound has been demonstrated to be an accurate and well‐tolerated tool in the diagnosis of non‐angulated paediatric distal forearm fractures. Ultrasound model simulation is a practical alternative for ultrasound education.

Aims

To describe the construction and validation of a low‐cost ultrasound model for the simulation of non‐angulated paediatric buckle and greenstick distal forearm fractures, for the educational instruction of healthcare providers.

Materials & Methods

The materials for the basic paediatric fracture model include turkey or chicken bones soaked in white vinegar to make them pliable, food‐grade gelatine and plastic containers. The fidelity can be improved by using synthetic gelatine set in a cylindrical mould, which can be placed within a manikin forearm.

Results

The models were validated by five paediatric emergency nurse practitioners and five paediatric emergency physicians. All participants were able to correctly identify the fracture types. All participants rated the models highly for both realism and educational value, with a preference for the turkey bone model as a better representation of buckle fractures.

Discussion

The ultrasound model described in this article can be made from low‐cost materials that can be easily sourced, which facilitates the identification of the different paediatric fracture subtypes, with the additional advantage of not causing discomfort to a child. A limitation of this model includes its inability to simulate the radiolucent epiphysis and represent Salter‐Harris fracture subtypes.

Conclusion

This low‐cost, high‐fidelity ultrasound model presents both an accurate and practical educational model for training healthcare providers, with a preference towards the turkey bone model.
Magnetic Mesoporous Silica Nanoparticles Cloaked by Red Blood Cell Membranes: Applications in Cancer Therapy
Authors: Xuan Mingjun , Shao Jingxin , Zhao Jie , Li Qi , Dai Luru , Li Junbai
Published: February 2018

Targeted drug delivery is an emerging technological strategy that enables nanoparticle systems to be responsive for tumor therapy. Magnetic mesoporous silica nanoparticles (MMSNs) were cloaked with red blood cell membrane (RBC). This integrates long circulation, photosensitizer delivery, and magnetic targeting for cancer therapy. In vivo experiments demonstrate that RBC@MMSNs can avoid immune clearance and achieve magnetic field (MF)‐induced high accumulation in a tumor. When light irradiation is applied, singlet oxygen rapidly generates from hypocrellin B (HB)‐loaded RBC@MMSN and leads to the necrosis of tumor tissue. Such a RBC‐cloaked magnetic nanocarrier effectively integrates immunological adjuvant, photosensitizer delivery, MF‐assisted targeting photodynamic therapy, which provides an innovative strategy for cancer therapy.
Palladium‐Catalyzed Decarbonylative Trifluoromethylation of Acid Fluorides
Authors: Keaveney Sinead T. , Schoenebeck Franziska
Published: February 2018

While acid fluorides can readily be made from widely available or biomass‐feedstock‐derived carboxylic acids, their use as functional groups in metal‐catalyzed cross‐coupling reactions is rare. This report presents the first demonstration of Pd‐catalyzed decarbonylative functionalization of acid fluorides to yield trifluoromethyl arenes (ArCF3). The strategy relies on a Pd/Xantphos catalytic system and the supply of fluoride for transmetalation through intramolecular redistribution to the the Pd center. This strategy eliminated the need for exogenous and detrimental fluoride additives and allows Xantphos to be used in catalytic trifluoromethylations for the first time. Our experimental and computational mechanistic data support a sequence in which transmetalation by R3SiCF3 occurs prior to decarbonylation.
Peptide‐Guided Assembly of Repeat Protein Fragments
Authors: Michel Erich , Plückthun Andreas , Zerbe Oliver
Published: February 2018

Herein, we present the peptide‐guided assembly of complementary fragments of designed armadillo repeat proteins (dArmRPs) to create proteins that bind peptides not only with high affinity but also with good selectivity. We recently demonstrated that complementary N‐ and C‐terminal fragments of dArmRPs form high‐affinity complexes that resemble the structure of the full‐length protein, and that these complexes bind their target peptides. We now demonstrate that dArmRPs can be split such that the fragments assemble only in the presence of a templating peptide, and that fragment mixtures enrich the combination with the highest affinity for this peptide. The enriched fragment combination discriminates single amino acid variations in the target peptide with high specificity. Our results suggest novel opportunities for the generation of new peptide binders by selection from dArmRP fragment mixtures.
Synthesis of (−)‐Hebelophyllene E: An Entry to Geminal Dimethyl‐Cyclobutanes by [2+2] Cycloaddition of Alkenes and Allenoates
Authors: Wahl Johannes M. , Conner Michael L. , Brown M. Kevin
Published: February 2018

The first synthesis of hebelophyllene E is presented, along with assignment of its previously unknown relative configuration through synthesis of epi‐ent‐hebelophyllene E. Development of a catalytic enantioselective [2+2] cycloaddition of alkenes and allenoates provides access to the required chiral geminal dimethylcyclobutanes. Key to its success is the identification of a novel oxazaborolidine catalyst which promotes the cycloaddition in high enantioselectivities with good functional‐group tolerance (9 examples, up to 97:3 e.r.). Thus, a late‐stage cycloaddition using a fully functionalized alkene, followed by a diastereoselective reduction allows a concise entry to this class of natural products.
A Ligand System for the Flexible Functionalization of Quantum Dots via Click Chemistry
Authors: Chen Yue , Cordero Jose M. , Wang Hua , Franke Daniel , Achorn Odin B. , Freyria Francesca S. , Coropceanu Igor , Wei He , Chen Ou , Mooney David J. , Bawendi Moungi G.
Published: February 2018

We present a novel ligand, 5‐norbornene‐2‐nonanoic acid, which can be directly added during established quantum dot (QD) syntheses in organic solvents to generate “clickable” QDs at a few hundred nmol scale. This ligand has a carboxyl group at one terminus to bind to the surface of QDs and a norbornene group at the opposite end that enables straightforward phase transfer of QDs into aqueous solutions via efficient norbornene/tetrazine click chemistry. Our ligand system removes the traditional ligand‐exchange step and can produce water‐soluble QDs with a high quantum yield and a small hydrodynamic diameter of approximately 12 nm at an order of magnitude higher scale than previous methods. We demonstrate the effectiveness of our approach by incubating azido‐functionalized CdSe/CdS QDs with 4T1 cancer cells that are metabolically labeled with a dibenzocyclooctyne‐bearing unnatural sugar. The QDs exhibit high targeting efficiency and minimal nonspecific binding.
Utility of silver‐coated fabrics as electrodes in electrotherapy applications
Authors: Ali Azam , Baheti Vijay , Militky Jiri , Khan Zaman
Published: February 2018

The present study deals with the deposition of silver particles onto knitted fabrics for possible applications in electrotherapy. The performance of silver‐coated fabrics was evaluated based on number of properties such as electrical conductivity, physiological comfort, antibacterial, and durability. Furthermore, the conductive fabrics were subjected to various repeated extensions and change in electrical resistivity was examined to simulate the performance of electrodes under various movements of human body. With increase in extension till 80%, very small change in volume electrical resistance was observed and after 90% extension, the electrical resistance was found to increase significantly. The volume resistance was found to remain constant for repeated extensions of over 100 cycles and also there was insignificant change in electrical resistivity when constant current was applied over prolonged time. The utility of silver‐coated fabrics can be expected as flexible textile electrodes in transcutaneous electrical nerve stimulation electrotherapy applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46357.
Fast swelling behaviors of thermosensitive poly(N‐isopropylacrylamide‐co‐methacryloxyethyltrimethyl ammonium chloride)/Na2WO4 cationic composite hydrogels
Authors: Xiao Zhixin , Tan Yun , Ma Jianjun , Wang Di , Yu Lina , Yue Fan , Xu Shimei , Huang Jianbin
Published: February 2018

A facile method was explored to synthesize thermosensitive poly[N‐isopropylacrylamide (NIPAM)‐co‐methacryloxyethyltrimethyl ammonium chloride (DMC)]/Na2WO4 cationic hydrogels via copolymerization of NIPAM and DMC in the presence of Na2WO4. Na2WO4 acted as both a physical crosslinking agent and a porogen precursor. The hydrogels were characterized by Fourier transform infrared spectroscopy, energy dispersive X‐ray, thermogravimetry, environmental scanning electron microscopy, and transmission electron microscopy. Effects of various salt solutions, pH solutions on swelling were investigated. Thermosensitivity of the hydrogels were also investigated in various polar solvents at different temperatures. The resultant hydrogel showed a fast swelling rate and good salt tolerance. The hydrogels reached the swelling equilibrium within 10 min. Moreover, the swelling ratio of the hydrogels increased with the increase of the polarity of the solvent. In the water, the swelling ratio decreased with the increasing of temperature, but remained at a high level even at 80 °C since the pore structure weaken the lower critical solution temperature effect of PNIPAM. The swelling ratio increased instead in low polar solvent, while it became negligible in nonpolar solvent with the increasing of temperature. The whole swelling kinetics was fit for Schott's pseudo‐second order model. The hydrogels have a great potential as catalysts and smart materials. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46375.
Study on spinnability of polyacrylonitrile solution based on dynamics simulation of dry‐jet wet spinning
Authors: Wang Jianning , Wang Tao , Xu Jing , Yu Jinchao , Zhang Yumei , Wang Huaping
Published: February 2018

Spinnability of polyacrylonitrile (PAN) solution was studied based on the spinning dynamics simulation and dry‐jet wet spinning experiments. The spinnability phenomenon was observed from the extruding and extending spinning experiments. The suitable conditions of normal extruding and extending of the PAN solution were obtained and the critical spinnability conditions were simulated. The experimental and simulation results showed that pressure drop through the spinneret was similar, while the temperature, velocity, and velocity gradient through the spinneret of PAN solution changed dramatically. It suggests that pressure drop can be chosen as one of the spinnability criterion for solution extruding and filaments forming during dry‐jet wet spinning. Furthermore, the effect of spinneret parameters and spinning conditions on spinnability was simulated. It shows that spinneret entrance angle, outlet channel length and width have impacts on the pressure drop and the die swell ratio, which suggests the spinneret design can be optimized to regulate the spinnability according to the simulation results. It is also found that some bad situations of spinnability such as sticking phenomenon can be avoided by decreasing spinning temperature or increasing mass flow rate to increase the pressure drop at a certain level under the premise of extruding smoothly. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46377.
2:2 Complexes from Diphenylpyridiniums and Cucurbit[8]uril: Encapsulation‐Promoted Dimerization of Electrostatically Repulsing Pyridiniums
Authors: Yang Bo , Yu Shang‐Bo , Wang Hui , Zhang Dan‐Wei , Li Zhan‐Ting
Published: February 2018

Rigid linear compounds G1 and G2, which contained two 4‐phenylpyridinium (PhPy+) units, have been prepared to investigate their binding with cucurbit[8]uril (CB[8]). X‐ray crystallographic structures revealed that in the solid state both compounds were included by CB[8], through antiparallel stacking, to form 2:2 quaternary complexes (G1)2@(CB[8])2 and (G2)2@(CB[8])2. For the former complex, CB[8] entrapped G1 by holding two heterodimers of its Py+ and benzyl units, which were at opposite ends of the backbone. In contrast, for the first time, the second complex disclosed parallel stacking of two cationic Py+ units of G2 in the cavity of CB[8] in the solid state, despite the generation of important electrostatic repulsion. Isothermal titrations in water afforded high apparent association constants of 4.36×106 and 6.43×106 m−1 for 1:1 complexes G1@CB[8] and G2@CB[8], respectively, and 1H NMR spectroscopy experiments in D2O confirmed a similar stacking pattern to that observed in the solid state. A previous study and crystal structures of the 2:1 complexes formed between three new controls, G3–5, and CB[8] did not display such unusual stacking of the cationic Py+ unit; this may be attributed to the multivalency of the two CB[8] encapsulation interactions.
Artificial Composite Anode Comprising High‐Capacity Silicon and Carbonaceous Nanostructures for Long Cycle Life Lithium‐Ion Batteries
Authors: Breitung Ben , Schneider Artur , Chakravadhanula Venkata Sai Kiran , Suchomski Christian , Janek Jürgen , Sommer Heino , Brezesinski Torsten
Published: February 2018

The use of functional nanomaterials is a common strategy to improve the mechanical and electrochemical properties of silicon anodes for secondary lithium‐ion cells. Here, we report the preparation of a structurally stable composite material with a unique morphology comprising small‐size silicon particles and especially branched carbonaceous nanofibers and the analysis of its cycling performance by galvanostatic measurements. This two‐phase composite was obtained from pyrolysis of blended silicon/cyanamide powders. The conversion of cyanamide to turbostratic carbon, rather than graphitic carbon nitride, was unexpected and appears to be catalyzed by accidental iron nanoparticles. Although the carbon content after pyrolysis was only about 7 %, half‐cells using electrodes containing the silicon/carbon composite outperformed other silicon‐based anode materials tested herein in terms of cyclability. After 300 cycles, they delivered two times higher capacity (>1.7 A h gsilicon−1 at C/10 and >0.5 A h gsilicon−1 at 1C in the 600–30 mV range when operated in constant current mode) than cells of similar loading with pristine silicon particles. The average fade rate per cycle was around 0.1 % between the 10th and 300th cycles, which is notable considering that the electrode structure and composition have not yet been optimized for battery applications.
Class composition as a frame of reference for teachers? The influence of class context on teacher recommendations
Authors: Boone Simon , Thys Sarah , Van Avermaet Piet , Van Houtte Mieke
Published: February 2018

Teacher recommendations are an important factor in the process of track placement, but research has shown that they are biased by pupils’ social background. Pupils from higher socio‐economic backgrounds are more likely to get the advice to enrol in an academic track than pupils from lower socio‐economic backgrounds, irrespective of prior achievement. Previous studies looked primarily at individual pupil or parent characteristics and their influence on teacher recommendations. However, in this article, the authors argue that the class context forms the frame of reference within which a teacher forms his/her recommendation for pupils. Therefore, this article investigates class composition effects on teacher recommendations at the transition between primary and secondary education in Flanders. More specifically, we look at the socio‐economic, ethnic and ability composition of a class. Multilevel logistic models were tested on data collected in 36 primary schools in the cities of Ghent and Antwerp in May 2015. The results show that only the ability composition of the classroom exerts a frame‐of‐reference effect on teacher recommendations for academically versus practically oriented tracks. A pupil with a low individual ability in a low‐ability class was more likely to get the advice to enrol in an academically oriented track than an equally able pupil in a high‐ability class. This study demonstrated the limited importance of class composition in teacher recommendations, but calls for more research on teacher bias in the process of track assignment.
Synthesizing Manganese Oxide Materials for Electrochemical Supercapacitors
Authors: Wang Jia , Wang Baocheng
Published: February 2018

The application of manganese oxide is limited for its difficulty to prevent the generated particles from aggregating. In our study, an optimized polyvinyl polypropylene‐assisted chemical coprecipitation method was adopted to improve the dispersion of manganese oxide particles, which was also facilely scalable in large‐scale production of materials. The results confirmed that both adding polyvinyl pyrrolidone and conducting thermal treatment for manganese oxide were effective methods to improve the electrochemical properties of manganese oxide.
Prognostic factors in breast phyllodes tumors: a nomogram based on a retrospective cohort study of 404 patients
Authors: Zhou Zhi‐Rui , Wang Chen‐Chen , Sun Xiang‐Jie , Yang Zhao‐Zhi , Chen Xing‐Xing , Shao Zhi‐Ming , Yu Xiao‐Li , Guo Xiao‐Mao
Published: February 2018

The aim of this study was to explore the independent prognostic factors related to postoperative recurrence‐free survival (RFS) in patients with breast phyllodes tumors (PTBs). A retrospective analysis was conducted in Fudan University Shanghai Cancer Center. According to histological type, patients with benign PTBs were classified as a low‐risk group, while borderline and malignant PTBs were classified as a high‐risk group. The Cox regression model was adopted to identify factors affecting postoperative RFS in the two groups, and a nomogram was generated to predict recurrence‐free survival at 1, 3, and 5 years. Among the 404 patients, 168 (41.6%) patients had benign PTB, 184 (45.5%) had borderline PTB, and 52 (12.9%) had malignant PTB. Fifty‐five patients experienced postoperative local recurrence, including six benign cases, 26 borderline cases, and 22 malignant cases; the three histological types of PTB had local recurrence rates of 3.6%, 14.1%, and 42.3%, respectively. Stromal cell atypia was an independent prognostic factor for RFS in the low‐risk group, while the surgical approach and tumor border were independent prognostic factors for RFS in the high‐risk group, and patients receiving simple excision with an infiltrative tumor border had a higher recurrence rate. A nomogram developed based on clinicopathologic features and surgical approaches could predict recurrence‐free survival at 1, 3, and 5 years. For high‐risk patients, this predictive nomogram based on tumor border, tumor residue, mitotic activity, degree of stromal cell hyperplasia, and atypia can be applied for patient counseling and clinical management. The efficacy of adjuvant radiotherapy remains uncertain.
A hierarchical prognostic model for risk stratification in patients with early breast cancer according to 18F‐fludeoxyglucose uptake and clinicopathological parameters
Authors: Cha Jongtae , Park Hyung Seok , Kim Dongwoo , Kim Hyun Jeong , Kim Min Jung , Cho Young Up , Yun Mijin
Published: February 2018

This study was to investigate a hierarchical prognostic model using clinicopathological factors and 18F‐fludeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) for recurrence‐free survival (RFS) in patients with early breast cancer who underwent surgery without neoadjuvant chemotherapy. A total of 524 patients with early breast cancer were included. The Cox proportional hazards model was used with clinicopathological variables and maximum standardized uptake value (SUVmax) on PET/CT. After classification and regression tree (CART) modeling, RFS curves were estimated using the Kaplan–Meier method and differences in each risk layer were assessed using the log‐rank test. During a median follow‐up of 46.2 months, 31 (5.9%) patients experienced recurrence. The CART model identified four risk layers: group 1 (SUVmax ≤6.75 and tumor size ≤2.0 cm); group 2 (SUVmax ≤6.75 and Luminal A [LumA] or TN tumor >2.0 cm); group 3 (SUVmax ≤6.75 and Luminal B [LumB] or human epidermal growth factor receptor 2 [HER2]‐enriched] tumor >2.0 cm); group 4 (SUVmax >6.75). Five‐year RFS was as follows: 95.9% (group 1), 98% (group 2), 82.8% (group 3), and 85.4% (group 4). Group 3 or group 4 showed worse prognosis than group 1 or group 2 (group 1 vs. group 3: P = 0.040; group 1 vs. group 4: P < 0.001; group 2 vs. group 3: P = 0.016; group 2 vs. group 4: P < 0.001). High SUVmax (>6.75) in primary breast cancer was an independent factor for poor RFS. In patients with low SUVmax, LumB or HER2‐enriched tumor >2 cm was also prognostic for poor RFS, similar to high SUVmax.
Synergy of Catechol‐Functionalized Zinc Oxide Nanorods and Porphyrins in Layer‐by‐Layer Assemblies
Authors: Burger Alexandra , Kunzmann Andreas , Costa Rubén D. , Srikantharajah Rubitha , Peukert Wolfgang , Guldi Dirk M. , Hirsch Andreas
Published: February 2018

Catechol‐functionalized, positively charged ZnO nanorods (NRs) and anionic porphyrins were integrated into layer‐by‐layer (LbL) assemblies. In general, this study focuses on the impact that different porphyrins, varying in size and number of negative charges, exert on the LbL architecture in terms of morphology and spectroscopy. In particular, through a combination of analytical methods, including UV/Vis spectroscopy, SEM, and profilometry, valuable insights into LbL assembly formation were gathered. A key feature was the surface coverage in the resulting films. Denser films and surface coverages were realized when highly negatively charged and sterically demanding porphyrins were employed. As a complement to basic characterization, the LbL assembled films were used to fabricate proof‐of‐concept solar cells.
Novel Synthesis of Anhydrous and Hydroxylated CuF2 Nanoparticles and Their Potential for Lithium Ion Batteries
Authors: Krahl Thoralf , Marroquin Winkelmann Friederike , Martin Andréa , Pinna Nicola , Kemnitz Erhard
Published: February 2018

Anhydrous nanoscopic CuF2 is synthesized from alkoxides Cu(OR)2 (R=Me, tBu) by their reaction either in pure liquid HF at −70 °C, or under solvothermal conditions at 150 °C using excess HF and THF as solvent. Depending on the synthesis method, nanoparticles of sizes between 10 and 100 nm are obtained. The compound is highly hygroscopic and forms different hydrolysis products under moist air, namely CuF2⋅2 H2O, Cu2(OH)F3, and Cu(OH)F, of which only the latter is stable at room temperature. CuF2 exhibits an electrochemical plateau at a potential of ≈2.7 V when cycled versus Li in half cell Li‐ion batteries, which is attributed to a non‐reversible conversion mechanism. The cell capacity in the first cycle depends on the particle size, being 468 mAh g−1 for ≈8 nm crystallite diameter, and 353 mAh g−1 for ≈12 nm crystallite diameter, referred to CuF2. However, such a high capacity cannot be sustained for several cycles and the capacity rapidly fades out. The cell voltage decreases to ≈2.0 V for CuF2⋅2 H2O, Cu2(OH)F3, and Cu(OH)F. As all the compounds studied in this work show irreversible conversion reactions, it can be concluded that copper‐based fluorides are unsuitable for Li‐ion battery applications.
Determination of Trapping Parameters of Tl2In2S3Se Layered Single Crystal by Thermoluminescence
Authors: Guler Ipek , Gasanly Nizami
Published: February 2018

Thermoluminescence (TL) measurements are performed to evaluate the trap states in Tl2In2S3Se layered single crystals. TL experiments are conducted with varying temperature from 10 to 300 K and warming rates from 0.2 to 1.0 K s−1. From the analysis of both initial rise and curve fitting methods, the activation energy of the traps is obtained as 23 meV. The Chen's method is also used to find activation energy. By means of this technique, the activation energy of the TL glow curve is calculated as 25 meV. From both Chen's method and curve fitting method, the existence of mixed order of kinetics in Tl2In2S3Se crystal is found. The cross section to capture of the trap center is found out from the results of curve fitting method. The trap distribution of the crystals is investigated with different temperatures of illumination at a constant warming rate of 0.8 K s−1. The temperatures of illumination change from 10 to 22 K. As a result of the increase in temperatures of illumination, the peak maximum values move to higher temperatures and intensity of the TL curves decreases. This behavior shows us that quasicontinuous traps distribution is present in Tl2In2S3Se layered single crystals.
The Yokohama system for reporting directly sampled endometrial cytology: The quest to develop a standardized terminology
Authors: Fulciniti Franco , Yanoh Kenji , Karakitsos Petros , Watanabe Jun , Di Lorito Alessia , Margari Niki , Maeda Yoshinobu , Kihara Maki , Norimatsu Yoshiaki , Kobayashi Tadao K. , Hirai Yasuo
Published: February 2018

Background

The main purpose of directly sampled endometrial cytology is to detect invasive endometrial malignancies. With this principle in mind, The Yokohama System (TYS) Working Group, composed of cytopathologists, surgical pathologists, and gynecologic oncologists met at the 2016 International Congress of Cytology, Yokohama, with the aim to publish a standardized reporting system inclusive of specific diagnostic categories and cytomorphologic criteria for uniform and reliable diagnosis of endometrial malignancies on directly sampled endometrial samples.

Methods

The diagnostic cytopathologic criteria previously published in the literature by the Japanese and Greek working group on endometrial cytology (Yanoh et al. [2012] Acta Cytol. 56:233; Margari et al. [2016] Diagn Cytopathol. 44:888‐901) were critically reviewed with the aim of correlating the diagnostic classes to well defined risk categories for endometrial carcinoma (EC). Moreover, two classes of “atypical” endometrial cells were correlated respectively to a low‐ and high risk group. Some methodological suggestions for the application of ancillary special technologies to liquid based samples were also given.

Results

The TYS group conceived a new Bethesda‐style classification for directly sampled endometrial cytology which correlates the cytologic diagnostic classes with definite risk categories. The cytomorphologic findings have been correlated to the molecular pathology of EC, also through the application of ancillary special techniques to liquid‐based samples.

Conclusions

The success of TYS will depend on the acceptance of TYS by all the relevant pathology and gynecologic oncology communities who, by their joint efforts, will adopt, critically evaluate, and optimize this method with the only aim of further improving the impact of endometrial cytology on patients’ care.
Ecological versatility and the assembly of multiple competitors: cautionary notes for assembly inferences
Authors: Saito Victor S. , Laroche Fabien , Siqueira Tadeu , Pavoine Sandrine
Published: February 2018

The role of niche differences and competition is invoked when one finds coexisting species to be more dissimilar in trait composition than expected at random in community assembly studies. This approach has been questioned as competition has been hypothesized to either lead to communities assembled by similar or dissimilar species, depending on whether species similarity reflects fitness or niche differences, respectively. A current problem is that the arguments used to draw relationships between competition and species similarity are based on pairwise theoretical examples, while in nature competition can occurs among a constellation of species with different levels of versatility in resources used. By versatility we mean the documented ability of some species to escape competition for commonly used resources by changing for marginal and unused resources. Thus, a versatile species will have the ability to decrease niche overlap with all other species when facing strong competitors. When these species are embedded in multiple interactions the role of pairwise niche and fitness differences could be reduced due to indirect effects and thus competition would not be detectable. Here we developed a coexistence theory where competition occurs simultaneously among multiple species with different levels of versatility and then used it in a simulation to unravel patterns of species similarity during community assembly. We found that simulated communities can be assembled by species with more, less or equal similarity compared to a null model when using a mean distance based metric (SES.MPD). However, contrasting these varied results, we consistently found species overdispersion using a nearest neighbor‐based metric (SES.MNTD), even when species differences reflected more directly their competitive abilities than their niche differences. Strong tendency to overdispersion emerged when high ecological versatility promoted large niche differences and enabled coexistence. This is because versatility to use marginal resources compensates possible fitness differences among species. Our findings provide mounting evidence of the important role of minimum niche differences and versatility in resource consumption for species embedded in multiple direct and indirect interactions.
Performance of an in situ activated carbon treatment to reduce PCB availability in an active harbor
Authors: Kirtay Victoria , Conder Jason , Rosen Gunther , Magar Victor , Grover Melissa , Arblaster Jennifer , Fetters Kyle , Chadwick Bart
Published: February 2018

In situ amendment of surface sediment with activated carbon is a promising technique for reducing the availability of hydrophobic organic compounds in surface sediment. The present study evaluated the performance of a logistically challenging activated carbon placement in a high-energy hydrodynamic environment adjacent to and beneath a pier in an active military harbor. Measurements conducted preamendment and 10, 21, and 33 months (mo) postamendment using in situ exposures of benthic invertebrates and passive samplers indicated that the targeted 4% (by weight) addition of activated carbon (particle diameter ≤74 µm) in the uppermost 10 cm of surface sediment reduced polychlorinated biphenyl availability by an average (± standard deviation) of 81 ± 11% in the first 10 mo after amendment. The final monitoring event (33 mo after amendment) indicated an approximate 90 ± 6% reduction in availability, reflecting a slight increase in performance and showing the stability of the amendment. Benthic invertebrate census and sediment profile imagery did not indicate significant differences in benthic community ecological metrics among the preamendment and 3 postamendment monitoring events, supporting existing scientific literature that this approximate activated carbon dosage level does not significantly impair native benthic invertebrate communities. Recommendations for optimizing typical site-specific assessments of activated carbon performance are also discussed and include quantifying reductions in availability and confirming placement of activated carbon. Environ Toxicol Chem 2018;37:1767–1777. Published 2018 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
Potential impact of effects on reproductive attributes induced by herbicides on a plant community
Authors: Reeg Jette , Heine Simon , Mihan Christine , Preuss Thomas G. , McGee Sean , Jeltsch Florian
Published: February 2018

Current herbicide risk assessment guidelines for nontarget terrestrial plants require testing effects on young, vulnerable life stages (i.e., seedling emergence [and subsequent growth] and vegetative vigor [growth and dry wt]) but not directly on the reproduction of plants. However, the European Food Safety Authority (EFSA) has proposed that effects on reproduction might be considered when evaluating the potential effects on plants. We adapted the plant community model for grassland (IBC-grass) to give insight into the current debate on the sensitivity of reproductive versus vegetative endpoints in ecological risk assessment. In an extensive sensitivity analysis of this model, we compared plant attributes potentially affected by herbicides and the consequences for long-term plant population dynamics and plant diversity. This evaluation was implemented by reducing reproductive as well as vegetative endpoints by certain percentages (e.g., 10–90%) as a theoretical assumption. Plant mortality and seed sterility (i.e., inability of seeds to germinate) were the most sensitive attributes. Our results indicated that effects on seed production at off-field exposure rates must be very strong to have an impact on the risk assessment. Otherwise, effects on seed production are compensated for by the soil seed bank. The present study highlights the usefulness of community level modeling studies to support regulators in their decisions on the appropriate risk assessment endpoints and provides confidence in their assessments. Environ Toxicol Chem 2018;37:1707–1722. © 2018 SETAC