bluuebunny/crossref_metadata_2025_split huggingface dataset:
Room‐Temperature Electrochemical Conversion of Metal–Organic Frameworks into Porous Amorphous Metal Sulfides with Tailored Composition and Hydrogen Evolution Activity
Authors: He Wenhui , Ifraemov Raya , Raslin Arik , Hod Idan 
Published: February 2018

AbstractThe conversion of metal–organic frameworks (MOFs) into inorganic nanomaterials is considered as an attractive means to produce highly efficient electrocatalysts for alternative‐energy related applications. Yet, traditionally employed MOF‐conversion conditions (e.g., pyrolysis) commonly involve multiple complex high‐temperature reaction processes, which often make it challenging to control the composition, pore structure, and active‐sites of the MOF‐derived catalysts. Herein, a general, simple, room‐temperature method is presented for a controlled electrochemical conversion of MOF (EC‐MOF) films into porous, amorphous metal sulfides (a‐MSx). Detailed X‐ray photoelectron spectroscopy analysis and control over independent EC‐MOF parameters (e.g., scan‐rate and potential window) enable to gain insights on the MOF‐conversion mechanisms, and in turn to fine‐tune the porosity and composition of the obtained MSx. As a result, a highly active amorphous cobalt sulfide (a‐CoSx) electrocatalyst can be designed for hydrogen evolution reaction in neutral pH. Furthermore, the adjustable nature of the EC‐MOF method allows to draw conclusions about the correlation between the concentration of catalytically active species ( sites) and the hydrogen evolution properties of the a‐CoSx. Given the method's generality and the diversity of available MOF structures, EC‐MOF provides a compelling platform for a rational design of a wide variety of active electrocatalytic materials.
Excitation‐Dependent Theranostic Nanosheet for Cancer Treatment
Authors: Guan Shanyue , Yang Di , Weng Yangziwan , Lu Heng , Meng Xiangmin , Qu Xiaozhong , Zhou Shuyun 
Published: February 2018

AbstractIn this work, a novel ruthenium complex loaded monolayer layered double hydroxide (LDH) (denoted as Ru(C‐bpy)2/mLDH) as supramolecular nanosensor is synthesized, which is greatly exclusive to the hypoxic tumor microenvironment. The Ru(C‐bpy)2/mLDH ultrathin sheet displays not only enhanced luminescence lifetime compared to the parent Ru(C‐bpy)2 alone, but also improved oxygen responsibility under an excitation of 488 or 800 nm. Moreover, the Ru(C‐bpy)2/mLDH is possessed of two‐photon fluorescence imaging ability under the 800 nm irradiation. In addition, the Ru(C‐bpy)2/mLDH can generate singlet oxygen with a high yield (φ∆) of 0.28 under the 520 nm irradiation, while the φ∆ of Ru(C‐bpy)2 is 0.19. Therefore, the Ru(C‐bpy)2/mLDH can be applied as a supramolecular theranostic agent with light‐switchable cancer imaging and photodynamic therapy properties.
Uncovering the Circular Polarization Potential of Chiral Photonic Cellulose Films for Photonic Applications
Authors: Zheng Hongzhi , Li Wanru , Li Wen , Wang Xiaojun , Tang Zhiyong , Zhang Sean Xiao‐An , Xu Yan 
Published: February 2018

AbstractCircularly polarized light (CPL) is central to photonic technologies. A key challenge lies in developing a general route for generation of CPL with tailored chiroptical activity using low‐cost raw materials suitable for scale‐up. This study presents that cellulose films with photonic bandgaps (PBG) and left‐handed helical sense have an intrinsic ability for circular polarization leading to PBG‐based CPL with extraordinary |g | values, well‐defiend handedness, and tailorable wavelength by the PBG change. Using such cellulose films, incident light ranging from near‐UV to near‐IR can be transformed to passive L‐CPL and R‐CPL with viewing‐side‐dependent handedness and |g | values up to 0.87, and spontaneous emission transformed to R‐CPL emission with |g | values up to 0.68. Unprecedented evidence is presented with theoretical underpinning that the PBG effect can stimulate the R‐CPL emission. The potential of cellulose‐based CPL films for polarization‐based encryption is illustrated. The evaporation‐induced self‐assembly coupled with nanoscale mesogens of cellulose nanocrystals opens new venues for technological advances and enables a versatile strategy for rational design and scalable manufacturing of organic and inorganic CPL films for photonic applications.
Liquid‐Crystalline Dynamic Networks Doped with Gold Nanorods Showing Enhanced Photocontrol of Actuation
Authors: Lu Xili , Zhang Hu , Fei Guoxia , Yu Bing , Tong Xia , Xia Hesheng , Zhao Yue 
Published: February 2018

AbstractA near‐infrared‐light (NIR)‐ and UV‐light‐responsive polymer nanocomposite is synthesized by doping polymer‐grafted gold nanorods into azobenzene liquid‐crystalline dynamic networks (AuNR‐ALCNs). The effects of the two different photoresponsive mechanisms, i.e., the photochemical reaction of azobenzene and the photothermal effect from the surface plasmon resonance of the AuNRs, are investigated by monitoring both the NIR‐ and UV‐light‐induced contraction forces of the oriented AuNR‐ALCNs. By taking advantage of the material's easy processability, bilayer‐structured actuators can be fabricated to display photocontrollable bending/unbending directions, as well as localized actuations through programmed alignment of azobenzene mesogens in selected regions. Versatile and complex motions enabled by the enhanced photocontrol of actuation are demonstrated, including plastic “athletes” that can execute light‐controlled push‐ups or sit‐ups, and a light‐driven caterpillar‐inspired walker that can crawl forward on a ratcheted substrate at a speed of about 13 mm min‐1. Moreover, the photomechanical effects arising from the two types of light‐triggered molecular motion, i.e., the trans–cis photoisomerization and a liquid‐crystalline–isotropic phase transition of the azobenzene mesogens, are added up to design a polymer “crane” that is capable of performing light‐controlled, robot‐like, concerted macroscopic motions including grasping, lifting up, lowering down, and releasing an object.
Reversible and Precisely Controllable p/n‐Type Doping of MoTe2 Transistors through Electrothermal Doping
Authors: Chang Yuan‐Ming , Yang Shih‐Hsien , Lin Che‐Yi , Chen Chang‐Hung , Lien Chen‐Hsin , Jian Wen‐Bin , Ueno Keiji , Suen Yuen‐Wuu , Tsukagoshi Kazuhito , Lin Yen‐Fu 
Published: February 2018

AbstractPrecisely controllable and reversible p/n‐type electronic doping of molybdenum ditelluride (MoTe2) transistors is achieved by electrothermal doping (E‐doping) processes. E‐doping includes electrothermal annealing induced by an electric field in a vacuum chamber, which results in electron (n‐type) doping and exposure to air, which induces hole (p‐type) doping. The doping arises from the interaction between oxygen molecules or water vapor and defects of tellurium at the MoTe2 surface, and allows the accurate manipulation of p/n‐type electrical doping of MoTe2 transistors. Because no dopant or special gas is used in the E‐doping processes of MoTe2, E‐doping is a simple and efficient method. Moreover, through exact manipulation of p/n‐type doping of MoTe2 transistors, quasi‐complementary metal oxide semiconductor adaptive logic circuits, such as an inverter, not or gate, and not and gate, are successfully fabricated. The simple method, E‐doping, adopted in obtaining p/n‐type doping of MoTe2 transistors undoubtedly has provided an approach to create the electronic devices with desired performance.
High‐Performance n‐Channel Organic Transistors Using High‐Molecular‐Weight Electron‐Deficient Copolymers and Amine‐Tailed Self‐Assembled Monolayers
Authors: Wang Yang , Hasegawa Tsukasa , Matsumoto Hidetoshi , Mori Takehiko , Michinobu Tsuyoshi 
Published: February 2018

AbstractWhile high‐performance p‐type semiconducting polymers are widely reported, their n‐type counterparts are still rare in terms of quantity and quality. Here, an improved Stille polymerization protocol using chlorobenzene as the solvent and palladium(0)/copper(I) as the catalyst is developed to synthesize high‐quality n‐type polymers with number‐average molecular weight up to 105 g mol−1. Furthermore, by sp2‐nitrogen atoms (sp2‐N) substitution, three new n‐type polymers, namely, pBTTz, pPPT, and pSNT, are synthesized, and the effect of different sp2‐N substitution positions on the device performances is studied for the first time. It is found that the incorporation of sp2‐N into the acceptor units rather than the donor units results in superior crystalline microstructures and higher electron mobilities. Furthermore, an amine‐tailed self‐assembled monolayer (SAM) is smoothly formed on a Si/SiO2 substrate by a simple spin‐coating technique, which can facilitate the accumulation of electrons and lead to more perfect unipolar n‐type transistor performances. Therefore, a remarkably high unipolar electron mobility up to 5.35 cm2 V−1 s−1 with a low threshold voltage (≈1 V) and high on/off current ratio of ≈107 is demonstrated for the pSNT‐based devices, which are among the highest values for unipolar n‐type semiconducting polymers.
A Printing‐Centric Approach to the Electrostatic Modification of Polymer/Clay Composites for Use in 3D Direct‐Ink Writing
Authors: Rauzan Brittany M. , Lehman Sean E. , McCracken Joselle M. , Lee Jonghun , Lin Xiao‐Min , Sandy Alec , Narayanan Suresh , Rogers Simon A. , Nuzzo Ralph G. 
Published: February 2018

AbstractPolymer/clay composite inks are exceptionally useful materials for fabrication processes based on 3D direct‐ink writing, however, there remains an insufficient understanding of how their physiochemical dynamics impact printability. Using a model system, N‐isopropylacrylamide/Laponite, the electrostatic interactions between Laponite platelets are modified to tune critical rheological properties in order to improve printability. Rheological measurements and X‐ray scattering experiments are carried out to monitor the nano/micro‐structural dynamics and complex physicochemical interactions of Laponite as it impacts complex modulus in the linear region, flow behavior, thixotropy, and yield stress of the composite ink. Modification of the electrostatic interactions between platelets reduces the yield stress of the material, while maintaining a complex microstructure that allows for sufficient recovery times upon removal of stress to form stable, and thus printable, filaments. A printing‐centric approach is established based on a fundamental understanding of electrostatic inter‐particle interactions, harnessing the innate microstructure of Laponite in 3D direct‐ink writing of composites.
Fabrication of Nearly‐Hyperuniform Substrates by Tailored Disorder for Photonic Applications
Authors: Piechulla Peter M. , Muehlenbein Lutz , Wehrspohn Ralf B. , Nanz Stefan , Abass Aimi , Rockstuhl Carsten , Sprafke Alexander 
Published: February 2018

AbstractDisordered optical substrates play a key role in photonic applications. Furthermore, structures of correlated, in particular hyperuniform, disorder are an emerging new class of photonic material enabling new ways of k‐space engineering. Yet, there are little to no feasible technologies that allow fabrication of tailored disordered structures to facilitate a tailored optical response. This work reports on a scalable method to fabricate substrates of tailored correlated disorder by self‐stabilized colloid deposition. Easy‐to‐access experimental parameters allow to tune lateral and vertical statistics of the disordered patterns. In addition, a model is presented that allows accurate prediction of mono‐ as well as polydisperse particle patterns. Correlation of disorder of the prepared patterns is investigated by means of the structure factor and optical measurements.
The Nature of Ion‐Pair Recognition by Tetra‐phosphonate Calix[4]pyrroles
Authors: Wang Teng , Liu Jingjing 
Published: February 2018

AbstractThe tetra‐phosphonate calix[4]pyrroles can function as multitopic receptors for ion‐pair recognition, and this process is mainly driven by noncovalent interactions (NCIs). In the present contribution, the NCIs in ion‐pair recognition by two representative receptors iiii and oooo, which differ in the relative orientation of the phosphonate groups, were explored by density functional theory calculations. The decomposition of the interaction energy suggests that electrostatic plays a dominant role in ion‐pair recognition, and it dictates that contact and separated arrangements are the favorable binding modes for iiii and oooo receptors, respectively. Furthermore, the calculation results predict that iiii receptors show superior binding affinities for organic chloride salts compared to oooo receptors. This study reveals the nature of ion‐pair recognition by tetra‐phosphonate calix[4]pyrroles, while providing valuable insights into the design of novel calix[4]pyrrole‐based ion‐pair receptors.
Boosting the Potassium Storage Performance of Alloy‐Based Anode Materials via Electrolyte Salt Chemistry
Authors: Zhang Qing , Mao Jianfeng , Pang Wei Kong , Zheng Tian , Sencadas Vitor , Chen Yuanzhen , Liu Yajie , Guo Zaiping 
Published: February 2018

AbstractPotassium‐ion batteries (PIBs) are promising energy storage systems because of the abundance and low cost of potassium. The formidable challenge is to develop suitable electrode materials and electrolytes for accommodating the relatively large size and high activity of potassium. Herein, Bi‐based materials are reported as novel anodes for PIBs. Nanostructural design and proper selection of the electrolyte salt have been used to achieve excellent cycling performance. It is found that the potassiation of Bi undergoes a solid‐solution reaction, followed by two typical two‐phase reactions, corresponding to Bi ↔ Bi(K) and Bi(K) ↔ K5Bi4 ↔ K3Bi, respectively. By choosing potassium bis(fluorosulfonyl)imide (KFSI) to replace potassium hexafluorophosphate (KPF6) in carbonate electrolyte, a more stable solid electrolyte interphase layer is achieved and results in notably enhanced electrochemical performance. More importantly, the KFSI salt is very versatile and can significantly promote the electrochemical performance of other alloy‐based anode materials, such as Sn and Sb.
Tuning Electronic Structure of NiFe Layered Double Hydroxides with Vanadium Doping toward High Efficient Electrocatalytic Water Oxidation
Authors: Li Pengsong , Duan Xinxuan , Kuang Yun , Li Yaping , Zhang Guoxin , Liu Wen , Sun Xiaoming 
Published: February 2018

AbstractBinary NiFe layer double hydroxide (LDH) serves as a benchmark non‐noble metal electrocatalyst for the oxygen evolution reaction, however, it still needs a relatively high overpotential to achieve the threshold current density. Herein the catalyst's electronic structure is tuned by doping vanadium ions into the NiFe LDHs laminate forming ternary NiFeV LDHs to reduce the onset potential, achieving unprecedentedly efficient electrocatalysis for water oxidation. Only 1.42 V (vs reversible hydrogen electrode (RHE), ≈195 mV overpotential) is required to achieve catalytic current density of 20 mA cm−2 with a small Tafel slope of 42 mV dec−1 in 1 m KOH solution, which manifests the best of NiFe‐based catalysts reported till now. Electrochemical analysis and density functional theory +U simulation indicate that the high catalytic activity of NiFeV LDHs mainly attributes to the vanadium doping which can modify the electronic structure and narrow the bandgap thereby bring enhanced conductivity, facile electron transfer, and abundant active sites.
Total duplication of the small single copy region in the angiosperm plastome: Rearrangement and inverted repeat instability in Asarum
Authors: Sinn Brandon T. , Sedmak Dylan D. , Kelly Lawrence M. , Freudenstein John V. 
Published: February 2018

Premise of the StudyAs more plastomes are assembled, it is evident that rearrangements, losses, intergenic spacer expansion and contraction, and syntenic breaks within otherwise functioning plastids are more common than was thought previously, and such changes have developed independently in disparate lineages. However, to date, the magnoliids remain characterized by their highly conserved plastid genomes (plastomes).MethodsIllumina HiSeq and MiSeq platforms were used to sequence the plastomes of Saruma henryi and those of representative species from each of the six taxonomic sections of Asarum. Sequenced plastomes were compared in a phylogenetic context provided by maximum likelihood and parsimony inferences made using an additional 18 publicly available plastomes from early‐diverging angiosperm lineages.Key ResultsIn contrast to previously published magnoliid plastomes and the newly sequenced Saruma henryi plastome published here, Asarum plastomes have undergone extensive disruption and contain extremely lengthy AT‐repeat regions. The entirety of the small single copy region (SSC) of A. canadense and A. sieboldii var. sieboldii has been incorporated into the inverted repeat regions (IR), and the SSC of A. delavayi is only 14 bp long. All sampled Asarum plastomes share an inversion of a large portion of the large single copy region (LSC) such that trnE‐UUC is adjacent to the LSC‐IR boundary.ConclusionsPlastome divergence in Asarum appears to be consistent with trends seen in highly rearranged plastomes of the monocots and eudicots. We propose that plastome instability in Asarum is due to repetitive motifs that serve as recombinatory substrates and reduce genome stability.
Herbarium specimens show patterns of fruiting phenology in native and invasive plant species across New England
Authors: Gallinat Amanda S. , Russo Luca , Melaas Eli K. , Willis Charles G. , Primack Richard B. 
Published: February 2018

Premise of the StudyPatterns of fruiting phenology in temperate ecosystems are poorly understood, despite the ecological importance of fruiting for animal nutrition and seed dispersal. Herbarium specimens represent an under‐utilized resource for investigating geographical and climatic factors affecting fruiting times within species, patterns in fruiting times among species, and differences between native and non‐native invasive species.MethodsWe examined over 15,000 herbarium specimens, collected and housed across New England, and found 3159 specimens with ripe fruits, collected from 1849–2013. We examined patterns in fruiting phenology among 37 native and 18 invasive woody plant species common to New England. We compared fruiting dates between native and invasive species, and analyzed how fruiting phenology varies with temperature, space, and time.Key ResultsSpring temperature and year explained a small but significant amount of the variation in fruiting dates. Accounting for the moderate phylogenetic signal in fruiting phenology, invasive species fruited 26 days later on average than native species, with significantly greater standard deviations.ConclusionsHerbarium specimens can be used to detect patterns in fruiting times among species. However, the amount of intraspecific variation in fruiting times explained by temporal, geographic, and climatic predictors is small, due to a combination of low temporal resolution of fruiting specimens and the protracted nature of fruiting. Later fruiting times in invasive species, combined with delays in autumn bird migrations in New England, may increase the likelihood that migratory birds will consume and disperse invasive seeds in New England later into the year.
A new commelinid monocot seed fossil from the early Eocene previously identified as Solanaceae
Authors: Särkinen Tiina , Kottner Sören , Stuppy Wolfgang , Ahmed Farah , Knapp Sandra 
Published: February 2018

Premise of the StudyFossils provide minimum age estimates for extant lineages. Here we critically evaluate Cantisolanum daturoides Reid & Chandler and two other early putative seed fossils of Solanaceae, an economically important plant family in the Asteridae.MethodsThree earliest seed fossil taxa of Solanaceae from the London Clay Formation (Cantisolanum daturoides) and the Poole and Branksome Sand Formations (Solanum arnense Chandler and Solanispermum reniforme Chandler) were studied using x‐ray microcomputed tomography (MCT) and scanning electron microscopy (SEM).Key ResultsThe MCT scans of Cantisolanum daturoides revealed a high level of pyrite preservation at the cellular level. Cantisolanum daturoides can be clearly excluded from Solanaceae and has more affinities to the commelinid monocots based on a straight longitudinal axis, a prominent single layer of relatively thin‐walled cells in the testa, and a clearly differentiated micropyle surrounded by radially elongated and inwardly curved testal cells. While the MCT scans show no internal preservation in Solanum arnense and Solanispermum reniforme, SEM images show the presence of several characteristics that allow the placement of these taxa at the stem node of Solanaceae.ConclusionsCantisolanum daturoides is likely a member of commelinid monocots and not Solanaceae as previously suggested. The earliest fossil record of Solanaceae is revised to consist of fruit fossil with inflated calyces from the early Eocene of Patagonia (52 Ma) and fossilized seeds from the early to mid‐Eocene of Europe (48–46 Ma). The new identity for Cantisolanum daturoides does not alter a late Cretaceous minimum age for commelinids.
How High Schools Become Empowering Communities: A Mixed‐Method Explanatory Inquiry into Youth‐Adult Partnership and School Engagement
Authors: Zeldin Shepherd , Gauley Josset Sky , Barringer Alexandra , Chapa Brie 
Published: February 2018

AbstractEducational reform efforts emphasize empowerment and engagement, but these concepts are rarely translated into policy or classroom practice. This inquiry explores how schools can become places where students take ownership over their own learning. Phase 1 of this inquiry, a survey of students from diverse high schools, examines pathways to school engagement. Results indicated that youth voice in decision‐making, particularly when the experience is situated within supportive adult relationships and a sense of safety, significantly predicts emotional and cognitive engagement. Phase 2, a case study of an exemplary high school, sought to explain these pathways. Grounded in the theoretical perspectives of “empowered community settings” and “youth‐adult partnership,” analyses highlighted the importance of a shared belief system and core instructional activities that were student‐centered, affirmative, and strength‐based. Within this context, the opportunity role structure allowed students to exercise voice in creating their own educational program. The relational environment offered partnership and safety for academic risk‐taking. Teachers broke down traditional roles and power hierarchies in ways that helped students discover their own sources of engagement. The article identifies ways that community psychologists, as policy framers and as researchers, can help schools become places of empowerment and engagement.
Spectroscopic Evidence for Aminomethylene (H−C̈−NH2)—The Simplest Amino Carbene
Authors: Eckhardt André K. , Schreiner Peter R. 
Published: February 2018

AbstractAlthough N‐heterocyclic carbenes have been well‐studied, the simplest aminocarbene, aminomethylene H−C̈−NH2, has not been spectroscopically identified to date. Herein we report the gas‐phase preparation of aminomethylene by high‐vacuum flash pyrolysis of cyclopropylamine and subsequent trapping of the pyrolysate in an inert argon matrix at 12 K. Aminomethylene was characterized by matching matrix IR and UV/Vis spectroscopic data with ab initio coupled cluster computations. After UV irradiation of the matrix aminomethylene rearranges to its isomer methanimine (formaldimine) H2C=NH. Based on our experimental results and computations aminomethylene has a singlet ground state with a reaction barrier of almost 46 kcal mol−1 to methanimine so that H‐tunneling is excluded.