bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preserving the Emission Lifetime and Efficiency of a Monolayer Semiconductor upon Transfer
Authors: Eizagirre Barker Simone , Wang Shaojun , Godiksen Rasmus H. , Castellanos Gabriel W. , Berghuis Matthijs , Raziman T. V. , Curto Alberto G. , Gómez Rivas Jaime 
Published: May 2019

AbstractMonolayer transition metal dichalcogenides (TMDs) are promising semiconductors for nanoscale photonics and optoelectronics due to their strong interactions with light. However, processes that integrate TMDs into nanophotonic and optoelectronic devices can introduce defects in the monolayers, resulting in lower emission efficiency. Quality control is therefore needed to process monolayer semiconductors effectively. Through micro‐photoluminescence and fluorescence lifetime imaging measurements, this work investigates the effects of encapsulation on the optical properties of TMD monolayers, focusing on the impact of different processing techniques and different dielectric environments. Spin coating a polymer layer on top of a TMD monolayer is shown to significantly reduce its emission lifetime and efficiency. In contrast, the soft transfer of a monolayer deposited on a polymer superstrate can preserve its intrinsic emission properties almost perfectly in various dielectric environments. This approach can be widely applied to integrate TMDs into devices and heterostructures while protecting sample quality, and demonstrates that intrinsic quantum efficiency and photoluminescence lifetimes of TMDs can be preserved upon transfer to different dielectric substrates.
Electroluminescent Warm White Light‐Emitting Diodes Based on Passivation Enabled Bright Red Bandgap Emission Carbon Quantum Dots
Authors: Jia Haoran , Wang Zhibin , Yuan Ting , Yuan Fanglong , Li Xiaohong , Li Yunchao , Tan Zhan'ao , Fan Louzhen , Yang Shihe 
Published: May 2019

AbstractThe development of efficient red bandgap emission carbon quantum dots (CQDs) for realizing high‐performance electroluminescent warm white light‐emitting diodes (warm‐WLEDs) represents a grand challenge. Here, the synthesis of three red‐emissive electron‐donating group passivated CQDs (R‐EGP‐CQDs): R‐EGP‐CQDs‐NMe2, ‐NEt2, and ‐NPr2 is reported. The R‐EGP‐CQDs, well soluble in common organic solvents, display bright red bandgap emission at 637, 642, and 645 nm, respectively, reaching the highest photoluminescence quantum yield (QY) up to 86.0% in ethanol. Theoretical investigations reveal that the red bandgap emission originates from the rigid π‐conjugated skeleton structure, and the ‐NMe2, ‐NEt2, and ‐NPr2 passivation plays a key role in inducing charge transfer excited state in the π‐conjugated structure to afford the high QY. Solution‐processed electroluminescent warm‐WLEDs based on the R‐EGP‐CQDs‐NMe2, ‐NEt2, and ‐NPr2 display voltage‐stable warm white spectra with a maximum luminance of 5248–5909 cd m−2 and a current efficiency of 3.65–3.85 cd A−1. The warm‐WLEDs also show good long‐term operational stability (L/L0 > 80% after 50 h operation, L0: 1000 cd m−2). The electron‐donating group passivation strategy opens a new avenue to realizing efficient red bandgap emission CQDs and developing high‐performance electroluminescent warm‐WLEDs.
Stable Metallic Enrichment in Conductive Filaments in TaOx‐Based Resistive Switches Arising from Competing Diffusive Fluxes
Authors: Ma Yuanzhi , Goodwill Jonathan M. , Li Dasheng , Cullen David A. , Poplawsky Jonathan D. , More Karren L. , Bain James A. , Skowronski Marek 
Published: May 2019

AbstractOxide‐based resistive‐switching devices hold promise for solid‐state memory technology. Information encoding is accomplished by electrically switching the device between two nonvolatile states with low and high resistance states (LRS/HRS). It is generally accepted that the change between these states is due to the motion of oxygen vacancies forming a continuous (LRS) or gapped (HRS) filament between the electrodes. Direct assessments of filaments are rare due to their small size and the difficulty of locating the filament. Electron microscopy experiments reveal the filament structure and chemistry in TaO2.0 ± 0.2‐based 150 × 150 nm2 devices with cross‐sectional geometry after forming with power dissipation lower than 1 mW. The filaments appear to be roughly hourglass‐shaped with a diameter of less than 10 nm and are composed of Ta‐rich and O‐poor mostly amorphous material with local compositions as Ta‐rich as TaO0.4. The as‐formed HRS has a gap up to 10 nm wide located next to the anode and composed of nearly stoichiometric TaO2.5. The tantalum and oxygen distribution is consistent with filaments formed by the motion of both Ta and O driven by temperature gradients (Soret effect) and an electric field. This interpretation points towards a new compact model of resistive‐switching devices.
Cold‐Sintered C0G Multilayer Ceramic Capacitors
Authors: Wang Dawei , Zhou Di , Song Kaixin , Feteira Antonio , Randall Clive A. , Reaney Ian M. 
Published: May 2019

AbstractMultilayer ceramic capacitors (MLCCs) based on (Bi0.95Li0.05)(V0.9Mo0.1)O4‐Na2Mo2O7 (BLVMO‐NMO), with εr = 39, temperature coefficient of capacitance, TCC ≈ ±0.01%, and tan δ = 0.01 at 1 MHz, are successfully fabricated by a cold‐sintering process at 150 °C. Scanning electron microscopy of the MLCCs combined with EDS mapping, X‐ray diffraction, and Raman spectroscopy reveals well‐laminated and undistorted dielectric layers composed of BLVMO and NMO discrete phases separated by Ag internal electrodes. Prototypes show comparable properties to C0G MLCCs (TCC = ±30 ppm °C−1 from −55 to +125 °C) currently commercially fabricated at 1100 °C using CaZrO3‐based dielectrics with glass sintering aids and Ni internal electrodes.
Type‐Switchable Inverter and Amplifier Based on High‐Performance Ambipolar Black‐Phosphorus Transistors
Authors: Zhang Le , Shao Li Yang , Gu Guoqiang , Wang Taihong , Sun Xiao Wei , Chen Xiaolong 
Published: May 2019

AbstractBlack phosphorus (BP), an emerging 2D layered material, is promising for nanoelectronic applications due to its high carrier mobility and saturation velocity. A high performance ambipolar BP field‐effect transistor (FET), fully assembled from 2D materials, is demonstrated. It exhibits two‐terminal mobility of 540 cm2 V−1 s−1 for holes and 250 cm2 V−1 s−1 for electrons at room temperature. The ambipolar charge transport of the BP FET allows it to operate as a p‐ and n‐type switchable inverter with operating frequency up to 160 kHz through simply changing the polarity of the supply voltage. At the same time, the voltage gain of the inverter is higher than 1, suggesting that it is suitable for logic‐circuit applications. Moreover, it is shown that the ambipolar BP FET can function as an output‐polarity controllable amplifier through tuning of the input and supply voltages. This demonstration paves the way for future BP applications in logic circuits.
Colonization, Baker's law, and the evolution of gynodioecy in Hawaii: implications from a study of Lycium carolinianum
Authors: Miller Jill S. , Blank Caitlin M. , Levin Rachel A. 
Published: May 2019

PremiseAs Baker’s law suggests, the successful colonization of oceanic islands is often associated with uniparental reproduction (self‐fertility), but the high incidence of dimorphism (dioecy, gynodioecy) on islands complicates this idea. Lycium carolinianum is widespread, occurring on the North American mainland and the Hawaiian Islands. We examined Baker's ideas for mainland and island populations of L. carolinianum and examined inbreeding depression as a possible contributor to the evolution of gynodioecy on Maui.MethodsControlled crosses were conducted in two mainland populations and two populations in Hawaii. Treatments included self and cross pollination, unmanipulated controls, and autogamy/agamospermy. Alleles from the self‐incompatibility S‐RNase gene were isolated and compared between mainland and island populations. Given self‐compatibility in Hawaii, we germinated seeds from self‐ and cross‐ treatments and estimated inbreeding depression using seven traits and a measure of cumulative fitness.ResultsMainland populations of Lycium carolinianum are predominately self‐incompatible with some polymorphism for self‐fertility, whereas Hawaiian populations are self‐compatible. Concordantly, S‐RNase allelic diversity is reduced in Hawaii compared to the mainland. Hawaiian populations also exhibit significant inbreeding depression.ConclusionsSelf‐compatibility in Hawaii and individual variation in self‐fertility in mainland populations suggests that a colonization filter promoting uniparental reproduction may be acting in this system. Comparison of S‐RNase variation suggests a collapse of allelic diversity and heterozygosity at the S‐RNase locus in Hawaii, which likely contributed to mate limitation upon arrival to the Pacific. Inbreeding depression coupled with autonomous self‐fertilization may have led to the evolution of gynodioecy on Maui.
Early Childhood Teachers’ Lives in Context: Implications for Professional Development in Under‐Resourced Areas
Authors: Schwartz Kate , Cappella Elise , Aber J. Lawrence , Scott Marc A. , Wolf Sharon , Behrman Jere R. 
Published: May 2019

AbstractThis study explores the personal, professional, and contextual conditions faced by early childhood education (ECE) teachers in under‐resourced settings and how these relate to teacher responsiveness to professional development (PD): namely, teacher attrition (a sign of PD failure when occurring shortly after PD), take‐up of offered PD, adherence to PD training/materials, and quality of implementation. We use data from six disadvantaged districts in the Greater Accra Region of Ghana and PD focused on implementation of a national, play‐based curriculum. Descriptive statistics indicate that ECE teachers (n = 302) face a multitude of barriers to high quality teaching across the bioecological model. Multilevel mixed effects models find that teachers with low job satisfaction are more likely to leave the school within the academic year. Teachers with moderate to severe depression are less likely to attend PD trainings. Senior teachers and those with poverty risks are less likely to adhere to PD material. Teachers with many time demand barriers are more likely to adhere to material. They also implement the content at higher observed quality as do teachers with bachelor's degrees and early childhood development (ECD) training. Take‐up of PD also predicts quality of implementation. Practice and research implications are discussed.
Schimke immunoosseous dysplasia and management considerations for vascular risks
Authors: Beleford Daniah T. , Diab Mohammad , Qubty William F. , Malloy Mary J. , Long Roger K. , Shieh Joseph T. 
Published: May 2019

AbstractSchimke immunoosseous dysplasia (SIOD) is a multisystemic condition characterized by early arteriosclerosis and progressive renal insufficiency, among other features. Many SIOD patients have severe, migraine‐like headaches, transient neurologic attacks, or cerebral ischemic events. Cerebral events could be exacerbated or precipitated by hypertension, and it is unclear how these are related to arteriosclerotic changes as dyslipidemia is also a feature of SIOD. The correlation between hypercholesterolemia and cardiovascular risk in SIOD is unclear. Also, the etiology and management of headaches is not well characterized. Here we report our clinical observations in the management of SIOD in a patient who was diagnosed in school age despite early signs and symptoms. We describe biallelic variants, including a previously unreported c.1931G>A (p.Arg644Gln) variant in SMARCAL1. We specifically investigated whether migraine‐like headaches and progressive nephropathy may be related to blood pressure dysregulation. We found a correlation between tighter blood pressure regulation using ambulatory blood pressure monitoring and a subjective decrease in headache symptoms. We discuss blood pressure medication management in SIOD. We also characterize dyslipidemia relative to atherosclerosis risks and provide new management strategies to consider for optimizing care.
The people or the place? An analysis of the protective factors of hate crime in multiethnic neighbourhoods in Australia
Authors: Benier Kathryn 
Published: May 2019

AbstractHate crime creates significant problems for individual victims and the social fabric of a community more broadly. Victimisation is most likely to occur around the victim's own neighbourhood, yet few studies examine how the neighbourhood context influences hate crime. This study uses data from the Australian Community Capacity Study involving 4,400 participants in 148 neighbourhoods in Brisbane. It examines whether it is characteristics of place (such as attitudes toward diversity, place attachment and social cohesion) that reduce hate crime, or whether it is interactions with fellow residents (such as frequency of neighbourly exchanges, number of friends, and number of acquaintances in the neighbourhood) that shelter residents from hate crime. Results demonstrate that characteristics of a place provide important protective factors against hate crime in the neighbourhood, rather than the number of social‐interactions between residents.
Effect of the hyaluronic acid‐poloxamer hydrogel on skin‐wound healing: in vitro and in vivo studies
Authors: Li Xiaojuan , Li Aimin , Feng Fan , Jiang Qiyu , Sun Huiwei , Chai Yantao , Yang Ruichuang , Wang Zhijie , Hou Jun , Li Ruisheng 
Published: May 2019

AbstractBackgroundRecent research into skin injury and wound healing has focused mainly on post‐trauma hemostasis, infection prevention, dermal regeneration and angiogenesis. However, less attention has been paid to air permeability and moisture loss prevention which also play important roles in injury healing.MethodsIn the present work, we prepared a hyaluronic acid‐poloxamer (HA‐POL) hydrogel and tested the therapeutic effect of the hydrogel on skin‐wound healing.ResultsThe HA‐POL hydrogel transformed from sol to gel at 30°C, close to body temperature, and had stable moisturizing properties. HA‐POL hydrogel promoted skin‐wound healing and increased protein accumulation in the wound area. HA‐POL hydrogel allowed greater air permeability than Band‐aid, a typical wound covering. Results from transwell assays showed that the HA‐POL hydrogel effectively isolated skin‐wounds from bacterial invasion.ConclusionThis work demonstrates the advantages of using HA‐POL gel materials in the treatment of cutaneous wounds.
Synthesis of Selenium‐Triphosphates (dNTPαSe) for More Specific DNA Polymerization
Authors: Hu Bei , Wang Yitao , Sun Shichao , Yan Weizhu , Zhang Chong , Luo Danyan , Deng Huiling , Hu Lillian R. , Huang Zhen 
Published: May 2019

Abstract2′‐Deoxynucleoside 5′‐(alpha‐P‐seleno)‐triphosphates (dNTPαSe) have been conveniently synthesized using a protection‐free, one‐pot strategy. One of two diastereomers of each dNTPαSe can be efficiently recognized by DNA polymerases, while the other is neither a substrate nor an inhibitor. Furthermore, this Se‐atom modification can significantly inhibit non‐specific DNA polymerization caused by mis‐priming. Se–DNAs amplified with dNTPαSe via polymerase chain reaction have sequences identical to the corresponding native DNA. In conclusion, a simple strategy for more specific DNA polymerization has been established by replacing native dNTPs with dNTPαSe.
Near‐Infrared‐Emitting Nitrogen‐Doped Nanographenes
Authors: Yamato Kairi , Sekiya Ryo , Suzuki Kaho , Haino Takeharu 
Published: May 2019

AbstractThe quantum‐size effect, which enables nanographenes to emit photoluminescence (PL) in the UV to visible region, has inspired intense research. However, the control of the PL properties of nanographenes through manipulation of their π‐system by post‐modifications is not well developed. By utilizing a ring‐closure reaction between an aromatic 1,2‐dicarboxylic acid and a 1,8‐naphthalenediamine derivative, which produces a perimidine framework, nitrogen‐doped nanographenes were realized. Two nanographenes produced by a one‐pot reaction of edge‐oxidized nanographene (GQD‐2) with 1,8‐naphthalenediamine derivatives (GQD‐1 a and GQD‐1 b) displayed an absorption band extending to >1000 nm; furthermore, the PL wavelength of GQD‐1 a was significantly red‐shifted into the near‐infrared (NIR) region in which it can be used for bioimaging. Time‐dependent DFT calculations of model nanographenes showed that the functional groups narrow the HOMO–LUMO gap, realizing the NIR‐emitting nanographenes.
Diterpenbiosynthese in Actinomyceten: Studien an Cattleyensynthase und Phomopsensynthase
Authors: Rinkel Jan , Steiner Simon T. , Dickschat Jeroen S. 
Published: May 2019

AbstractDrei Diterpensynthasen aus Actinomyceten wurden studiert. Das erste Enzym aus Streptomyces cattleya produzierte die neue Verbindung Cattleyen. Zwei weitere Enzyme aus Nocardia testacea und Nocardia rhamnosiphila wurden als Phomopsensynthasen identifiziert. Der Cyclisierungsmechanismus der Cattleyensynthase und der EI‐MS‐Fragmentierungsmechanismus ihres Produktes wurden extensiv durch Inkubationsexperimente mit isotopenmarkierten Vorläufern studiert. Oxidative Transformationen erweiterten den chemischen Strukturraum dieser einzigartigen Diterpene.
Cryogenic Exfoliation of Non‐layered Magnesium into Two‐Dimensional Crystals
Authors: Zhang Chen , Xu Yingfeng , Lu Ping , Wei Chenyang , Zhu Chenxi , Yao Heliang , Xu Fangfang , Shi Jianlin 
Published: May 2019

AbstractPhysical exfoliation of layered precursors is one of the most prevailing techniques to prepare two‐dimensional (2D) crystals, which, however, is considered to be intrinsically inapplicable to non‐layered bulks. Now, plane cleavage differentiation is identified in metallic magnesium at cryogenic temperature (CT), and a cryogenic exfoliation strategy of non‐layered magnesium into 2D crystals is developed. The cleavage anisotropy of the Mg lattice in response to the external mechanical stress originates from the CT‐induced specific inactivation of basal slip, which results in the basal cleavage perpendicular to c axis. The exfoliated novel 2D Mg crystals exhibit remarkable localized surface plasmon resonances, holding great promise for the applications in harvesting and converting solar energy. Beyond creating a new member for the burgeoning 2D family, this study may provide a useful tool for the physical exfoliations of various non‐layered materials.
Intermolecular C−H Amidation of (Hetero)arenes to Produce Amides through Rhodium‐Catalyzed Carbonylation of Nitrene Intermediates
Authors: Yuan Si‐Wen , Han Hui , Li Yan‐Lin , Wu Xueli , Bao Xiaoguang , Gu Zheng‐Yang , Xia Ji‐Bao 
Published: May 2019

AbstractAmide bond formation is one of the most important reactions in organic chemistry because of the widespread presence of amides in pharmaceuticals and biologically active compounds. Existing methods for amides synthesis are reaching their inherent limits. Described herein is a novel rhodium‐catalyzed three‐component reaction to synthesize amides from organic azides, carbon monoxide, and (hetero)arenes via nitrene‐intermediates and direct C−H functionalization. Notably, the reaction proceeds in an intermolecular fashion with N2 as the only by‐product, and either directing groups nor additives are required. The computational and mechanistic studies show that the amides are formed via a key Rh‐nitrene intermediate.
Uranocenium: Synthesis, Structure, and Chemical Bonding
Authors: Guo Fu‐Sheng , Chen Yan‐Cong , Tong Ming‐Liang , Mansikkamäki Akseli , Layfield Richard A. 
Published: May 2019

AbstractAbstraction of iodide from [(η5‐C5iPr5)2UI] (1) produced the cationic uranium(III) metallocene [(η5‐C5iPr5)2U]+ (2) as a salt of [B(C6F5)4]−. The structure of 2 consists of unsymmetrically bonded cyclopentadienyl ligands and a bending angle of 167.82° at uranium. Analysis of the bonding in 2 showed that the uranium 5f orbitals are strongly split and mixed with the ligand orbitals, thus leading to non‐negligible covalent contributions to the bonding. Investigation of the dynamic magnetic properties of 2 revealed that the 5f covalency leads to partially quenched anisotropy and fast magnetic relaxation in zero applied magnetic field. Application of a magnetic field leads to dominant relaxation by a Raman process.
Kinetic Treatments for Catalyst Activation and Deactivation Processes based on Variable Time Normalization Analysis
Authors: Martínez‐Carrión Alicia , Howlett Michael G. , Alamillo‐Ferrer Carla , Clayton Adam D. , Bourne Richard A. , Codina Anna , Vidal‐Ferran Anton , Adams Ralph W. , Burés Jordi 
Published: May 2019

AbstractProgress reaction profiles are affected by both catalyst activation and deactivation processes occurring alongside the main reaction. These processes complicate the kinetic analysis of reactions, often directing researchers toward incorrect conclusions. We report the application of two kinetic treatments, based on variable time normalization analysis, to reactions involving catalyst activation and deactivation processes. The first kinetic treatment allows the removal of induction periods or the effect of rate perturbations associated with catalyst deactivation from kinetic profiles when the quantity of active catalyst can be measured. The second treatment allows the estimation of the activation or deactivation profile of the catalyst when the order of the reactants for the main reaction is known. Both treatments facilitate kinetic analysis of reactions suffering catalyst activation or deactivation processes.
Diterpene Biosynthesis in Actinomycetes: Studies on Cattleyene Synthase and Phomopsene Synthase
Authors: Rinkel Jan , Steiner Simon T. , Dickschat Jeroen S. 
Published: May 2019

AbstractThree diterpene synthases from actinomycetes have been studied. The first enzyme from Streptomyces cattleya produced the novel compound cattleyene. The other two enzymes from Nocardia testacea and Nocardia rhamnosiphila were identified as phomopsene synthases. The cyclisation mechanism of cattleyene synthase and the EIMS fragmentation mechanism of its product were extensively studied by incubation experiments with isotopically labelled precursors. Oxidative transformations expanded the chemical space of these unique diterpenes.
Viscoelastic Conjugated Polymer Fluids
Authors: Shinohara Akira , Pan Chengjun , Guo Zhenfeng , Zhou Liyang , Liu Zhonghua , Du Lei , Yan Zhichao , Stadler Florian J. , Wang Lei , Nakanishi Takashi 
Published: May 2019

AbstractThe introduction of optoelectronic functions into viscoelastic polymers can yield highly sophisticated soft materials for biomedical devices and autonomous robotics. However, viscoelasticity and excellent optoelectronic properties are difficult to achieve because the presence of a large number of π‐conjugated moieties drastically stiffens a polymer. Here, we report a variation of additive‐free viscoelastic conjugated polymers (VE‐CPs) at room temperature by using an intact π‐conjugated backbone and bulky, yet flexible, alkyl side chains as “internal plasticizers.” Some of these polymers exhibit gel‐ and elastomer‐like rheological behaviors without cross‐linking or entanglement. Furthermore, binary blends of these VE‐CPs exhibit a never‐seen‐before dynamic miscibility with self‐restorable and mechanically induced fluorescence color changes.