bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hybrid Solar Absorber–Emitter by Coherence‐Enhanced Absorption for Improved Solar Thermophotovoltaic Conversion
Authors: Wang Yang , Zhou Lin , Zhang Ye , Yu Jianyu , Huang Baili , Wang Yuxi , Lai Yun , Zhu Shining , Zhu Jia 
Published: October 2018

AbstractSpectrum selective absorbers and emitters, with advantages of high temperature tolerance, wide angle insensitivity, and scalable fabrication processes, are crucial components for solar thermophotovoltaics (STPV). A bifunctional hybrid absorber–emitter (HAE) for efficient STPV by sequentially depositing HfO2/Mo/HfO2 films on a metallic surface is demonstrated here. Simultaneous broadband solar absorption and narrowband infrared emission are enabled by the same surface of the structure. By fine steering coherent perfect absorption of the ultrathin Mo film and destructive interference of interfacial reflections across the top HfO2 layer, the HAE exhibits a measured emissivity of 0.97 at 1.8 µm as well as an average absorptivity of ≈80% over 400–1000 nm, respectively, both of which are well maintained under nearly omnidirectional irradiance (≈80°) and up to 1373 K thermal stability test. The features of multiple coherence‐enhanced all‐in‐one single‐surface HAE (dual‐spectrum selectivity, wide angle tolerance, high temperature stability, etc.), make the HAE a good candidate for specialized efficient STPV. As a demonstration, it is theoretically shown that the HAE‐based cage‐type STPV can enable a maximal system efficiency increment of >15% compared to the double‐side planar systems, providing a potential route leading to integrated STPV–TPV systems for all‐climate operation in future.
Optimization on Molecular Restriction for Highly Efficient Thermally Activated Delayed Fluorescence Emitters
Authors: Chen Zhi‐Peng , Wang De‐Qi , Zhang Ming , Wang Kai , Shi Yi‐Zhong , Chen Jia‐Xiong , Tao Wen‐Wen , Zheng Cai‐Jun , Tao Si‐Lu , Zhang Xiao‐Hong 
Published: October 2018

AbstractTo develop efficient thermally activated delayed fluorescence (TADF) emitters with optimal molecular restrictions for organic light‐emitting diodes (OLEDs), four novel TADF emitters are designed and synthesized: 5′‐(9,9‐dimethylacridin‐10(9H)‐yl)‐[1,1′:3′,1″‐terphenyl]‐2′,4,4″‐tricarbonitrile (oAcTBC), 5′‐(10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)‐[1,1′:3′,1″‐terphenyl]‐2′,4,4″‐tricarbonitrile (oSpTBC), 2′‐(9,9‐dimethylacridin‐10(9H)‐yl)‐[1,1′:3′,1″‐terphenyl]‐4,4″,5′‐tricarbonitrile (mAcTBC), and 2′‐(10H‐spiro[acridine‐9,9′‐fluoren]‐10‐yl)‐[1,1′:3′,1″‐terphenyl]‐4,4″,5′‐tricarbonitrile (mSpTBC). The four compounds have similar constituent segments but different molecular restrictions by enhancing either segment rigidity or steric hindrance. The OLEDs using oAcTBC, oSpTBC, mAcTBC, and mSpTBC as the emitter exhibit maximum external quantum efficiencies of 20.9%, 26.8%, 19.2%, and 18.9%, respectively, consistent with their photoluminescence quantum yield values of 83.88%, 93.24%, 76.64%, and 65.02%. The best performance is successfully realized by oSpTBC with the optimal molecular restriction. This work suggests that appropriately enhancing the molecular restrictions with more rigid constituent segments is an optimal approach to improve the efficiencies of TADF emitters.
p‐Type Doped AlAsSb/GaSb Resonant Tunneling Diode Photodetector for the Mid‐Infrared Spectral Region
Authors: Pfenning Andreas , Hartmann Fabian , Weih Robert , Emmerling Monika , Worschech Lukas , Höfling Sven 
Published: October 2018

AbstractMid‐infrared (MIR) resonant tunneling diode (RTD) photodetectors based on a p‐type doped AlAsSb/GaSb double‐barrier quantum well (DBQW) are proposed and investigated for their optoelectronic transport properties. At room temperature, a distinct resonant tunneling current with a region of negative differential conductance is measured. The peak‐to‐valley current ratio (PVCR) is 1.51. To provide photosensitivity within the MIR spectral region, a lattice‐matched quaternary low‐bandgap GaInAsSb absorption layer with cutoff wavelength of λ = 2.77 μm is integrated near the DBQW. Under illumination with infrared light, photogenerated minority electrons within the absorption layer can drift toward the DBQW, where they accumulate and cause a shift of the current–voltage characteristics toward smaller bias voltages, which can be exploited to measure the incident MIR light power. In a tunable diode laser absorption spectroscopy experiment, the RTD photodetector is used to identify three distinct water absorption lines in the MIR close to λ = 2.61 μm. By adjusting the absorption layer doping concentration, the RTD quantum efficiency can be increased by a factor of 10, resulting in a sensitivity of S = 2.71 A W−1, which corresponds to an estimated multiplication factor of M = 8.6.
Flexible Gray‐Scale Surface Patterning Through Spatiotemporal‐Interference‐Based Femtosecond Laser Shaping
Authors: Li Bohong , Jiang Lan , Li Xiaowei , Lin Zemeng , Huang Lingling , Wang Andong , Han Weina , Wang Zhi , Lu Yongfeng 
Published: October 2018

AbstractThe function of a laser‐shaped material depends on the geometrical morphology of its laser‐induced surface structures, which is mainly determined by the spatial intensity distribution of the laser. However, conventional patterning methods based on laser shaping techniques have shortcomings in efficiency or flexibility. A novel patterning method is developed in the present study for mask‐free and flexible fabrication of surface structures through a time‐saving spatiotemporal‐interference‐based femtosecond laser shaping technique that is based on a Michelson interferometer. The phase‐difference distribution is controlled by a spatial light modulator so that the interference intensity distribution can be modulated to user‐designed shapes. The congruence between the interference intensity distribution and the geometries on phase holograms enables the generation of phase holograms without complicated algorithms and time‐consuming calculations. This uniquely simple technique realizes flexible gray‐scale patterning on bulk material surfaces with a single femtosecond laser pulse. Thus, by using the on‐the‐fly technique, fabrication of large‐area surface structures is realized. Moreover, this technique is applied to fabricate complex structures through splicing. As an application example, three types of terahertz filters, including band‐stop and band‐pass filters, are fabricated successfully; their transmittance is in good agreement with the finite‐difference time‐domain simulation results.
Incorporating Thermally Activated Delayed Fluorescence into Mechanochromic Luminescent Emitters: High‐Performance Solution‐Processed Yellow Organic Light Emitting Diodes
Authors: Zeng Xuan , Zhou Tao , Liu Jiangle , Wu Kailong , Li Shuqi , Xiao Xiao , Zhang Yu , Gong Shaolong , Xie Guohua , Yang Chuluo 
Published: October 2018

AbstractMultifunctional materials with stimuli‐responsive features are demonstrated to be promising smart materials. In this work, three multifunctional materials, namely 5TzPmPXZ, 7TzPmPXZ, and 5,7TzPmPXZ, are constructed by integrating phenoxazine with electron‐acceptor core [1,2,4]triazolo[1,5‐a]pyrimidine (TzPm). Intriguingly, these materials exhibit not only thermally activated delayed fluorescence but also multicolor luminescence switching which is caused by the phase transitions between microcrystalline and amorphous states upon external stimuli. Moreover, the solution‐processed organic light emitting diodes (OLEDs) fabricated with these materials furnish a high external quantum efficiency up to 14.3% and the Commission Internationale de l'Eclairage coordinates of (0.43, 0.53), which represents the state‐of‐the‐art performance for solution‐processed yellow OLEDs.
Highly Focused Library‐Based Engineering of Candida antarctica Lipase B with (S)‐Selectivity Towards sec‐Alcohols
Authors: Cen Yixin , Li Danyang , Xu Jian , Wu Qiongsi , Wu Qi , Lin Xianfu 
Published: October 2018

AbstractCandida antarctica lipase B (CALB) is one of the most extensively used biocatalysts in both academia and industry and exhibits remarkable (R)‐enantioselectivity for various chiral sec‐alcohols. Considering the significance of tailor‐made stereoselectivity in organic synthesis, a discovery of enantiocomplementary lipase mutants with high (R)‐ and (S)‐selectivity is valuable and highly desired. Herein, we report a highly efficient directed evolution strategy, using only 4 representative amino acids, namely, alanine (A), leucine (L), lysine (K), tryptophan (W) at each mutated site to create an extremely small library of CALB variants requiring notably less screening. The obtained best mutant with three mutations W104V/A281L/A282K displayed highly reversed (S)‐selectivity towards a series of sec‐alcohol with E values up to 115 (conv. 50%, ee 94%). Compared with the previously reported (S)‐selective CALB variant, W104A, a single mutation provided less selectivity, while the synergistic effects of three mutations in the best variant endow better (S)‐selectivity and a broader substrate scope than the W104A variant. Structural analysis and molecular dynamics simulation unveiled the source of reversed enantioselectivity.magnified image
Enantioselective and Diastereodivergent Access to α‐Substituted α‐Amino Acids via Dual Iridium and Copper Catalysis
Authors: Zhang Jiacheng , Huo Xiaohong , Li Bowen , Chen Zhouli , Zou Yashi , Sun Zhenliang , Zhang Wanbin 
Published: October 2018

AbstractThe work reported within this paper describes an example of the application of bimetallic catalysts system in allylic substitution reactions. The development of new nucleophiles and the control of enantio‐ and diastereoselectivity are the main research topics in this area. An improvement in the reactivity and diastereoselectivity has been realized for the dual Ir/Cu catalyzed allylic alkylation of inactive prochiral nucleophiles, under mild reaction conditions. Furthermore, the choice of the metallacyclic iridium complex and chiral Cu‐Phox complex combination allows for access to all four stereoisomers from the same starting materials with excellent enantioselectivity and diastereoselectivity (up to >99% ee and >20:1 dr). Significantly, this method provides a stereodivergent access to 2‐amino‐3‐methylpent‐4‐acid ester, an important fragment for the synthesis of Halipeptin A.magnified image
Precursor Self‐Assembly Identified as a General Pathway for Colloidal Semiconductor Magic‐Size Clusters
Authors: Wang Linxi , Hui Juan , Tang Junbin , Rowell Nelson , Zhang Baowei , Zhu Tingting , Zhang Meng , Hao Xiaoyu , Fan Hongsong , Zeng Jianrong , Han Shuo , Yu Kui 
Published: October 2018

AbstractLittle is known about the formation pathway of colloidal semiconductor magic‐size clusters (MSCs). Here, the synthesis of the first single‐ensemble ZnSe MSCs, which exhibit a sharp optical absorption singlet peaking at 299 nm, is reported; their formation is independent of Zn and Se precursors used. It is proposed that the formation of MSCs starts with precursor self‐assembly followed by Zn and Se covalent bond formation to result in immediate precursors (IPs) which can transform into the MSCs. It is demonstrated that the IPs in cyclohexane appear transparent in optical absorption, and become visible as MSCs exhibiting one sharp optical absorption peak when a primary amine is added at room temperature. It is shown that when the preparation of the IP is controlled to be within the induction period, which occurs prior to nucleation and growth of conventional quantum dots (QDs), the resulting MSCs can be produced without the complication of the simultaneous coproduction of conventional QDs. The present study reveals the existence of precursor self‐assembly which leads to the formation of colloidal semiconductor MSCs and provides insights into a multistep nucleation process in cluster science.
3D Nanofabrication of SiOC Ceramic Structures
Authors: Brigo Laura , Schmidt Johanna Eva Maria , Gandin Alessandro , Michieli Niccolò , Colombo Paolo , Brusatin Giovanna 
Published: October 2018

AbstractShaping ceramic materials at the nanoscale in 3D is a phenomenal engineering challenge, that can offer new opportunities in a number of industrial applications, including metamaterials, nano‐electromechanical systems, photonic crystals, and damage‐tolerant lightweight materials. 3D fabrication of sub‐micrometer ceramic structures can be performed by two‐photon laser writing of a preceramic polymer. However, polymer conversion to a fully ceramic material has proven so far unfeasible, due to lack of suitable precursors, printing complexity, and high shrinkage during ceramic conversion. Here, it is shown that this goal can be achieved through an appropriate engineering of both the material and the printing process, enabling the fabrication of preceramic 3D shapes and their transformation into dense and crack‐free SiOC ceramic components with highly complex, 3D sub‐micrometer architectures. This method allows for the manufacturing of components with any 3D specific geometry with fine details down to 450 nm, rapidly printing structures up to 100 µm in height that can be converted into ceramic objects possessing sub‐micrometer features, offering unprecedented opportunities in different application fields.
Ultralight Layer‐by‐Layer Self‐Assembled MoS2‐Polymer Modified Separator for Simultaneously Trapping Polysulfides and Suppressing Lithium Dendrites
Authors: Wu Jingyi , Zeng Hongxia , Li Xiongwei , Xiang Xiao , Liao Yonggui , Xue Zhigang , Ye Yunsheng , Xie Xiaolin 
Published: October 2018

AbstractPolysulfide shuttling and uncontrollable lithium dendrite growth have hampered the application of lithium–sulfur (Li–S) batteries. Although various materials have been utilized to overcome these obstacles, simple and scalable methods are still needed for Li–S battery commercialization. It is shown for the first time that the layer‐by‐layer (LbL) self‐assembly of 2D nanomaterials can be used to controllably fabricate multifunctional separators that simultaneously trap polysulfides and suppress lithium dendrite growth. The double‐sided “nanobrick wall” structure, constructed by MoS2/poly(diallyl dimethyl ammonium chloride) hybrid in conjunction with poly(acrylic acid) (PAA), provides a physical shield against polysulfides and the chemical adsorption of such species by MoS2 and PAA. At the same time, the robust and Li‐ion conducting MoS2 layers strengthen the separator and regulate Li deposition, thereby effectively suppressing Li dendrite formation. As a result, a simple sulfur cathode battery with an ultralight separator coating (0.10 mg cm−2) is able to achieve an outstanding cycle stability with a capacity decay as low as 0.029% per cycle over 2000 cycles and a reversible areal capacity ≈2.0 mAh cm−2 at 1 C. The proposed LbL approach opens the door to the simple, scalable, and economic fabrication of advanced functional separators for use in the real world.
Architecture of the femoral and tibial diaphyses in relation to body mass and composition: Research from whole‐body CT scans of adult humans
Authors: Lacoste Jeanson Alizé , Santos Frédéric , Villa Chiara , Banner Jytte , Brůžek Jaroslav 
Published: October 2018

AbstractObjectivesRecent investigations have evaluated the influence of body composition on long bones in order to overcome the limits of body mass (BM) estimation methods and eventually lead to studying nutrition in past populations. Knowing how fat mass (FM) and fat‐free mass (FFM) impact the skeleton would also enhance the understanding of mobility, activity, and locomotion derived from bone architecture. We investigated the relationship between BM and composition, and the architecture of the entire tibial and femoral diaphyses in an adult sample representative of a wide range of variation in age, BM, and composition.Materials and methodsBody composition was measured directly from 78 whole‐body CT scans for which the age, sex, BM, and stature were recorded. The entire diaphyseal thickness, volume, curvature, and cross‐sectional geometry parameters of both the femur and tibia were numerically extracted.ResultsFM correlates with large portions of the femoral thickness in females only. FFM correlates with the femoral diaphysis in males but not in females. FFM correlates with the tibia architecture in both sexes, while FM is correlated in males exclusively.DiscussionBM and body components influence the architecture of the diaphysis of lower limb long bones in sex‐specific patterns that are mostly reflected in their thickness and can be recorded, in some cases, for their strength, rigidity, and volume. Our results suggest that (1) long bone diaphyses should be thoroughly studied, as a whole, when possible; and (2) BM and body components should be accounted for when deriving activity, mobility, or locomotion patterns from cortical bone.
Diphosphahexaarenes as Highly Fluorescent and Stable Materials
Authors: Hindenberg Philip , Busch Marvin , Paul Alexander , Bernhardt Moritz , Gemessy Patrick , Rominger Frank , Romero‐Nieto Carlos 
Published: October 2018

AbstractOligoarenes are regarded as subunits of π‐extended carbon nanoforms, such as graphene and nanotubes, with exceptional technological importance. Fused arenes can thus provide fundamental insight into the nature of the electronic properties of fused polyaromatic rings and pave the way for the design of extended graphene‐like materials. However, large π‐extended arenes often show low stability. Herein we report the straightforward preparation of linearly fused diphosphahexaarenes containing two six‐membered phosphorus heterocycles. They are highly stable towards air, water, and light over months in both solution and the solid state. Single‐crystal X‐ray crystallography confirmed the molecular structure of all derivatives. Investigations of their optoelectronic properties revealed that the diphosphahexaarenes exhibit ambipolar redox behavior and high fluorescence quantum yields. Embedding six‐membered phosphorus rings into large acenes thus opens up new opportunities for the investigation of polyaromatic systems.
Dexamethasone Reduces the Foreign Body Reaction to Intraneural Electrode Implants in the Peripheral Nerve of the Rat
Authors: De la Oliva Natàlia , Navarro Xavier , del Valle Jaume 
Published: October 2018

ABSTRACTIntraneural electrodes must be in intimate contact with nerve fibers to have a proper function, but this interface is compromised due to the foreign body reaction (FBR). The FBR is characterized by a first inflammatory phase followed by a second anti‐inflammatory and fibrotic phase, which results in the formation of a tissue capsule around the implant, causing physical separation between the active sites of the electrode and the nerve fibers. We have tested systemically several anti‐inflammatory drugs such as dexamethasone (subcutaneous), ibuprofen and maraviroc (oral) to reduce macrophage activation, as well as clodronate liposomes (intraperitoneal) to reduce monocyte/macrophage infiltration, and sildenafil (oral) as an antifibrotic drug to reduce collagen deposition in an FBR model with longitudinal Parylene C intraneural implants in the rat sciatic nerve. Treatment with dexamethasone, ibuprofen, or clodronate significantly reduced the inflammatory reaction in the nerve in comparison to the saline group after 2 weeks of the implant, whereas sildenafil and maraviroc had no effect on infiltration of macrophages in the nerve. However, only dexamethasone was able to significantly reduce the matrix deposition around the implant. Similar positive results were obtained with dexamethasone in the case of polyimide‐based intraneural implants, another polymer substrate for the electrode. These results indicate that inflammation triggers the FBR in peripheral nerves, and that anti‐inflammatory treatment with dexamethasone may have beneficial effects on lengthening intraneural interface functionality. Anat Rec, 301:1722–1733, 2018. © 2018 Wiley Periodicals, Inc.
Learning while playing: Children's Forest School experiences in the UK
Authors: Coates Janine K. , Pimlott‐Wilson Helena 
Published: October 2018

Children's outdoor play is declining, despite clear links between play, learning and development. Alternative learning initiatives which provide children with a diversity of play opportunities, including the chance to play outdoors, are therefore needed. One such programme, Forest School, is increasing in popularity in the UK and internationally, yet little is understood about its impact on children's learning, or how alternative approaches are informing learning in mainstream settings. This novel study examined primary school children's experiences of engaging in a Forest School programme in relation to this intersection between formal and informal approaches to learning. It explored how children interpret their experiences when faced with a fusion of learning environments and critically evaluates the benefits children realise, when asked to reflect on their learning engagement in both classroom and outdoor settings.Interviews were conducted with 33 children from two mainstream primary schools in England who had recently completed a 6‐week Forest School programme. A rigorous phenomenological thematic analysis revealed three inter‐related themes: a break from routine; learning through play; collaboration and teamwork. The findings suggest that the blending of Forest School with mainstream settings contributes to children's social, cognitive, emotional and physical skill development through experiential learning using play. These findings are significant because they not only emphasise the values of social constructivist play‐pedagogy which underpin Forest School practice, but also highlight the need for primary schools to consider learning outside of the classroom as an effective pedagogy.
Uptake and function of membrane‐destabilizing cationic nanogels for intracellular drug delivery
Authors: Liechty William B. , Scheuerle Rebekah L. , Vela Ramirez Julia E. , Peppas Nicholas A. 
Published: October 2018

AbstractThe design of intracellular drug delivery vehicles demands an in‐depth understanding of their internalization and function upon entering the cell to tailor the physicochemical characteristics of these platforms and achieve efficacious treatments. Polymeric cationic systems have been broadly accepted to be membrane disruptive thus being beneficial for drug delivery inside the cell. However, if excessive destabilization takes place, it can lead to adverse effects. One of the strategies used to modulate the cationic charge is the incorporation of hydrophobic moieties, thus increasing the hydrophobic content. We have demonstrated the successful synthesis of nanogels based on diethylaminoethyl methacrylate and poly(ethylene glycol) methyl ether methacrylate. Addition of the hydrophobic monomers tert‐butyl methacrylate or 2‐(tert‐butylamino)ethyl methacrylate shows improved polymer hydrophobicity and modulation of the critical swelling pH. Here, we evaluate the cytocompatibility, uptake, and function of these membrane‐destabilizing cationic methacrylated nanogels using in vitro models. The obtained results suggest that the incorporation of hydrophobic monomers decreases the cytotoxicity of the nanogels to epithelial colorectal adenocarcinoma cells. Furthermore, analysis of the internalization pathways of these vehicles using inhibitors and imaging flow cytometry showed a significant decrease in uptake when macropinocytosis/phagocytosis inhibitors were present. The membrane‐disruptive abilities of the cationic polymeric nanogels were confirmed using three different models. They demonstrated to cause hemolysis in sheep erythrocytes, lactate dehydrogenase leakage from a model cell line, and disrupt giant unilamellar vesicles. These findings provide new insights of the potential of polymeric nanoformulations for intracellular delivery.