bluuebunny/crossref_metadata_2025_split huggingface dataset:
Entanglement Locking in the Unique Elasticity of Polydimethylsiloxane Rubbers
Authors: Villani Vincenzo , Lavallata Vito 
Published: April 2020

AbstractThe viscoelasticity behavior of the polydimethylsiloxane (PDMS) rubber blends of high molecular weight polymers modified by low molecular weight agents is studied in compression mode by stress–strain curves, the creep and step‐strain, and dynamic‐mechanical experiments. The strain spectra highlight the dynamics of active chains at high frequencies and of dangling ends in the low frequencies field. At low deformation, the blending agent enhances the elastic properties by increasing the density of the active chains in the rubber network, in agreement with the classical theories of elasticity. At high deformation, in analogy with the rheological studies on similar liquid blends, the Entanglement Locking model is proposed: the short chains of the blending agent are adsorbed on entanglement sites of long dangling chains, giving effective crosslinks via high entropy dynamics. In this way, the long‐term entanglement locking enhances the density of active chains and elastic behavior. At high deformation, the entanglement locking model enriches the rubber elasticity theories according to the tube network model and Mooney–Rivlin equation. The models herein and the possibility they offer for improving rubber viscoelasticity are valuable for the development of polymer physics and technology.
Stereoselective Polymerization of an Aromatic Vinyl Monomer to Access Highly Syndiotactic Poly(vinyl alcohol)
Authors: Huang Jianming , Jiang Yang , Zhang Zhen , Li Shihui , Cui Dongmei 
Published: April 2020

AbstractStreoregular poly(vinyl alcohol) is hard to obtain because vinyl alcohol is unstable relative to its tautomer acetaldehyde, and the monomer precursor vinyl ester is poisonous to the coordination catalyst. Herein, the coordination polymerization of 2‐vinyl‐2,1‐borazanaphthalene (BN2VN) is reported by the linked or unlinked half‐sandwich ligands attached scandium precursors ((FluSiMe3)Sc(CH2SiMe3)2(THF) (THF = tetrahydrofuran, 1), (FluCH2CH2‐NHC‐R)Sc(CH2SiMe3)2(THF) (R = mesityl 2, iPr 3, Me 4), and (FluCH2Py)Sc(CH2SiMe3)2 (5) for the first time. Among these precursors, complex 5 converts 600 equivalents of BN2VN into polymer within 5 min to reach an activity as high as 8.99 × 105 g molSc−1 h−1. The resultant products show excellent syndiotacticity and melting temperatures above 300 °C, which can be transferred to syndiotactic poly(vinyl alcohol) with 90% rr triad content by postpolymerization oxidation.
White Matter Hyperintensities Related to Parkinson's Disease Executive Function
Authors: Linortner Patricia , McDaniel Colin , Shahid Marian , Levine Taylor F. , Tian Lu , Cholerton Brenna , Poston Kathleen L. 
Published: April 2020

AbstractBackgroundPeople with Parkinson's disease (PD) can develop multidomain cognitive impairments; however, it is unclear whether different pathologies underlie domain‐specific cognitive dysfunction.ObjectivesWe investigated the contribution of vascular copathology severity and location, as measured by MRI white matter hyperintensities (WMHs), to domain‐specific cognitive impairment in PD.MethodsWe studied 85 PD (66.6 ± 9.2 years) and 18 control (65.9 ± 6.6) participants. Using the Fazekas scale for rating the severity of WMH, we subdivided PD into 14 PD–WMH+ and 71 PD–WMH–. Participants underwent global, executive, visuospatial, episodic memory, and language testing. We performed nonparametric permutation testing to create WMH probability maps based on PD‐WMH group and cognitive test performance.ResultsThe PD–WMH+ group showed worse global and executive cognitive performance than the PD–WMH– group. On individual tests, the PD–WMH+ group showed worse Montreal Cognitive Assessment (MoCA), Stroop, Symbol Digit Modalities Test (SDMT), and Digit Span scores. WMH probability maps showed that in the PD–WMH+ group, worse Stroop was associated with lesions centered around the corticospinal tract (CST), forceps major, inferior‐fronto‐occipital fasciculus, and superior longitudinal fasciculus; worse SDMT with lesions around the CST, forceps major, and posterior corona radiata; worse Digit Span with lesions around the posterior corona radiata; and worse MoCA with lesions around the CST.ConclusionsWe found that WMH severity was associated with PD executive dysfunction, including worse attention, working memory, and processing speed. Disruption of key white matter tracts in proximity to vascular lesions could contribute to these specific cognitive impairments. Early treatment of vascular disease might mitigate some executive dysfunction in a subset of patients with PD.
Resurrecting the phoenix: When an assay fails
Authors: Srinivasan Bharath , Kantae Vasudev , Robinson James 
Published: April 2020

AbstractUnderstanding protein‐small‐molecule interactions is a critical component of rational drug‐design. Structure‐activity relationship (SAR)‐guided medicinal chemistry is informed by the biological outcome, as assessed by biochemical activity or cellular effect, of chemical modifications on small molecules. The effectiveness of SAR is reliant on the sturdiness and durability of assay design and the quality of information garnered from assays. Lack of quality data at this step can lead to obstruction of the drug discovery pipeline with profound implications for the timelines of introducing a drug into the market. Hence, it would not be an overstatement to consider biochemical/biological assays as the backbone of drug‐discovery. Enzyme assays can fail for many different reasons, with the enzyme and the substrate being the principal players. Lack of clarity can hamper progress and can lead to mounting costs and potentially losing competitive advantage. Although each assay is unique and requires a specific approach to troubleshoot the problem at hand, there are general guidelines that can be followed to maximize the chances of success. This review is a step‐by‐step attempt at reintroducing fundamental biochemical concepts within the context of an enzyme assay, delineating probable causes for failure and potential approaches to get an assay back up and running.
CSRR‐loaded UWB monopole antenna with electronically tunable triple band‐notch characteristics for cognitive radio applications
Authors: Shome Partha P. , Khan Taimoor , Laskar Rabul H. 
Published: April 2020

AbstractThis article introduces a compact configuration of printed monopole antenna with electronically tunable band‐notched function for ultra‐wideband (UWB) applications. A partially grounded rectangular shaped monopole is designed initially to achieve UWB behavior. The notch characteristics are then introduced by employing three complementary split‐ring resonators (CSRRs) on the radiating surface. The proposed antenna exhibits an ultra‐wide operating band ranging from 1.98 to 10.54 GHz with the notched frequencies at 2.37, 3.03, and 4.18 GHz, respectively. In order to accomplish versatility in the antenna operation, the notched frequencies are controlled electronically by implementing three varactor diodes in between the split‐ring slots. By applying an appropriate reverse bias voltage, the triple notched bands are tuned over the frequency bands: 1.58‐2.12 GHz, 2.24‐2.68 GHz, and 3.08‐3.78 GHz, respectively. A prototype with an overall dimension of 34.9 × 31.3 × 1.6 mm3 has been fabricated to experimentally determine the tuning capability of the antenna structure. The experimental result establishes close correspondence with the simulated antenna properties. The suggested antenna can be implemented practically to reject interferences from complete 1.5‐2.1 GHz LTE systems, and 2.5/3.5 GHz‐WiMAX bands, simultaneously. The capability of tuning three notched‐bands together is distinctive and has not been reported in the published literature to the best of authors' knowledge.
Pseudospectral method for assessing stability robustness for linear time‐periodic delayed dynamical systems
Authors: Borgioli Francesco , Hajdu David , Insperger Tamas , Stepan Gabor , Michiels Wim 
Published: April 2020

SummaryThe article presents a pseudospectral approach to assess the stability robustness of linear time‐periodic delay systems, where periodic functions potentially present discontinuities and the delays may also periodically vary in time. The considered systems are subject to linear real‐valued time‐periodic uncertainties affecting the coefficient matrices, and the presented method is able to fully exploit structure and potential interdependencies among the uncertainties. The assessment of robustness relies on the computation of the pseudospectral radius of the monodromy operator, namely, the largest Floquet multiplier that the system can attain within a given range of perturbations. Instrumental to the adopted novel approach, a solver for the computation of Floquet multipliers is introduced, which results into the solution of a generalized eigenvalue problem which is linear w.r.t. (samples of) the original system matrices. We provide numerical simulations for popular applications modeled by time‐periodic delay systems, such as the inverted pendulum subject to an act‐and‐wait controller, a single‐degree‐of‐freedom milling model and a turning operation with spindle speed variation.
Structural and tensile characteristics of reduced graphene oxide/poly (vinyl alcohol) composite films: Influence of ultraviolet irradiation
Authors: Bozdoğan Altan , Aksakal Baki , Yargi Onder , Şahintürk Utkan 
Published: April 2020

AbstractThe influence of ultraviolet (UV) radiation on the structural and uniaxial tensile characteristics of reduced graphene oxide (rGO)/poly(vinyl alcohol) (PVA) composite films produced by using various contents (0‐10 wt%) of rGO obtained by a microwave‐assisted reduction process was investigated. With increasing rGO content, significant reinforcing effects of the rGO sheets were seen on the tensile characteristics of the unirradiated rGO/PVA composite films, that is, increases in the stiffness and rigidity and decreases in the strain at break values. After UV exposure times from minutes up to 1 hour, for all the rGO contents, the rGO/PVA composite films had improved tensile strength and modulus values as well as considerable improvement in the stress‐strain behavior in spite of great decreases in the strain at break values. The structural changes responsible for the improvement in the tensile strength and Young's modulus of the rGO/PVA composite films were associated with the development of strong intermolecular interactions between the rGO sheets and the PVA polymer chains through the formation of hydrogen bonds. Deterioration of the mechanical characteristics, especially strain at break values, was mainly due to the photodegradation of the structural units induced by UV radiation leading to the formation of some free radicals caused by the chemical bond breakages in the polymer chains as well as the weakening of intermolecular interactions such as hydrogen bonds. Correlation between the changes in the tensile properties and the structure of the rGO/PVA composite films were sought by analyzing tensile testing, fourier transform infrared/attenuated total reflectance (FTIR/ATR), and UV‐visible spectral results.
Children's effortful control moderates the relationship between parental psychological control and adolescents’ depressive symptoms
Authors: Li Qianqian , Fu Rui , Yao Lining , Xing Shufen 
Published: April 2020

AbstractThe present study examined the interactions of adolescents' temperamental effortful control and parental psychological control on adolescents' depressive symptoms in China. A total of 440 adolescents between the ages of 14 and 20 years (Mage = 15.7) participated in this study. Data on parental psychological control, adolescents' depressive symptoms and effortful control were collected from self‐reports. Results showed that adolescents' effortful control moderated the link between paternal psychological control and adolescents' depressive symptoms. Specifically, for adolescents with low levels of effortful control, paternal psychological control was positively associated with increased depressive symptoms whereas for adolescents with a high level of effortful control, this association was not significant. In addition, maternal psychological control was associated with adolescents' depressive symptoms. These findings confirmed and extended previous findings on the associations between parental psychological control, children's temperament effortful control, and depressive symptoms in adolescence.
A meta‐analytic review of paraprofessional‐implemented interventions for students with autism spectrum disorder
Authors: Walker Virginia L. , Coogle Christan Grygas , Lyon Kristin J. , Turf Mindi 
Published: April 2020

AbstractThe purpose of this meta‐analysis was to summarize single‐case design studies in which paraprofessionals delivered interventions to students with autism spectrum disorder in school settings. We descriptively analyzed participant and intervention characteristics and study quality and estimated intervention effect using Tau‐U across student participants. Overall, paraprofessional‐implemented interventions resulted in large to very large changes across a range of student outcomes and intervention conditions. Interventions delivered by paraprofessionals in inclusive school settings and within the context of whole group instructional arrangements resulted in significant changes in student outcomes as compared to interventions delivered in self‐contained classrooms and within one‐to‐one and small group instructional arrangements. We present implications for research and practice and discuss limitations.
Synthesis and Simulation Study of Right Silver Bipyramids via Seed‐Mediated Growth cum Selective Oxidative Etching Approach
Authors: Tavakkoli Yaraki Mohammad , Daqiqeh Rezaei Soroosh , Middha Eshu , Tan Yen Nee 
Published: April 2020

AbstractIn this study, a simple method to synthesize right silver bipyramid (AgBP) nanostructures via the seed‐mediated growth cum oxidative etching approach in aqueous solution is developed. The key strategy of this method is to control the growth and etching process by careful adjustment of the reactants concentration. Ascorbic acid (AA) is used to reduce silver precursor while cetyltrimethylammonium bromide stabilizer is used to direct the preferential growth of (100) facets. The presence of Cu2+ and AA in the reaction mixture also enable in‐situ generation of H2O2, leading to selective etching of (111) facets, which is crucial to the formation of anisotropic AgBPs. The structure‐properties of AgBPs is systematically investigated through a series of experiments and theoretical simulations. Transmission electron microscope images and X‐ray diffraction patterns of the as‐synthesized AgBPs show the formation of single crystalline twined nanostructures with a relatively high yield. These results suggest the important role of the excitation of electric dipole in enhancing the electric field at the six sharp corners of AgBPs, making them especially promising for a wide range of technological applications including surface‐enhanced Raman scattering with a significant enhancement factor of 1.50 × 105 as demonstrated herein.
Contextualizing technology: Between gender pluralization and class reproduction
Authors: Ottemo Andreas , Berge Maria , Silfver Eva 
Published: April 2020

AbstractA diverse body of feminist scholarship has addressed the masculine orientation of Western engineering education for at least four decades. Among critiques specifically targeting curriculum, a recurrent line of argumentation highlights its reductionist framing and narrow focus on mathematics and technology. The argument is that these traits represent a masculine orientation and that women would gain from a curriculum more oriented towards the context and applicability of technical knowledge. Simultaneously, researchers working in a Bernsteinian, social realist, educational tradition have suggested that, from a social‐class perspective, it is important to provide all students with access to theoretical, abstract and context‐independent knowledge. This article explores the resultant, theoretical tension between these two positions. Our empirical starting point is a recently completed ethnographic study of a male‐dominated bachelor's degree engineering program in Sweden. This program's curriculum repeatedly emphasizes the value of experiential and contextually rooted knowledge over contextless and mathematically modeled knowledge. Borrowing Bernstein's terminology, we argue that such emphasis represents a privileging of horizontal discourse over vertical and that, as such, said curriculum potentially deprives the male, working‐class students of access to powerful knowledge. We further highlight how the program represents a poor target for the line of feminist critique identified above, despite being strongly male dominated. We thereby shed light on challenges related to formulating (intersectional) critiques of the engineering curriculum simultaneously attentive to both class and gender. Conclusively, we argue that efforts directed at making the engineering curriculum more inclusive can learn from both feminist and social realist lines of argumentation.
Synergistically Coupling Black Phosphorus Quantum Dots with MnO2 Nanosheets for Efficient Electrochemical Nitrogen Reduction Under Ambient Conditions
Authors: Wang Chuang , Gao Jian , Zhao Jing‐Geng , Yan Du‐Juan , Zhu Xiao‐Dong 
Published: April 2020

AbstractThe electrochemical nitrogen reduction reaction (NRR) is a promising strategy of nitrogen fixation into ammonia under ambient conditions. However, the development of electrochemical NRR is highly bottlenecked by the expensive noble metal catalysts. As a representative 2D nonmetallic material, black phosphorus (BP) has the valence electron structure similar to nitrogen, which can effectively adsorb the inactive nitrogen molecule and activate its triple bond. In addition, the relatively weak hydrogen adsorption can restrict the competitive and vigorous hydrogen evolution reaction. Herein, ultrafine BP quantum dots (QDs) are prepared via liquid‐phase exfoliation and then assembled on catalytically active MnO2 nanosheets through van der Waals interactions. The obtained BP QDs/MnO2 catalyst demonstrates admirable synergetic effects in electrochemical NRR. The monodisperse BP QDs providing major activity manifest excellent ammonia production steadily with high selectivity, which benefits from the robust confinement of the BP QDs on the wrinkled MnO2 nanosheets with decent activity. A high ammonia yield rate of 25.3 µg h−1 mgcat.−1 and faradic efficiency of 6.7% can be achieved at −0.5 V (vs RHE) in 0.1 m Na2SO4 electrolyte, which are dramatically superior to either component. The isotopic labelling and other control tests further exclude the external contamination possibility and attest the genuine activity.
UV–Vis–NIR Full‐Range Responsive Carbon Dots with Large Multiphoton Absorption Cross Sections and Deep‐Red Fluorescence at Nucleoli and In Vivo
Authors: Jiang Lei , Ding Haizhen , Xu Mingsheng , Hu Xiaolong , Li Shengli , Zhang Mingzhu , Zhang Qiong , Wang Qiyang , Lu Siyu , Tian Yupeng , Bi Hong 
Published: April 2020

AbstractCarbon dots (CDs), with excellent optical property and cytocompatibility, are an ideal class of nanomaterials applied in the field of biomedicine. However, the weak response of CDs in the near‐infrared (NIR) region impedes their practical applications. Here, UV–vis–NIR full‐range responsive fluorine and nitrogen doped CDs (N‐CDs‐F) are designed and synthesized that own a favorable donor‐π‐acceptor (D‐π‐A) configuration and exhibit excellent two‐photon (λex = 1060 nm), three‐photon (λex = 1600 nm), and four‐photon (λex = 2000 nm) excitation upconversion fluorescence. D‐π‐A‐conjugated CDs prepared by solvothermal synthesis under the assistance of ammonia fluoride are reported and are endowed with larger multiphoton absorption (MPA) cross sections (3PA: 9.55 × 10−80 cm6 s2 photon−2, 4PA: 6.32 × 10−80 cm8 s3 photon−3) than conventional organic compounds. Furthermore, the N‐CDs‐F show bright deep‐red to NIR fluorescence both in vitro and in vivo, and can even stain the nucleoli of tumor cells. A plausible mechanism is proposed on the basis of the strong inter‐dot and intra‐dot hydrogen bonds through NH···F that can facilitate the expanding of conjugated sp2 domains, and thus not only result in lower highest occupied molecular orbital‐lowest unoccupied molecular orbital energy level but also larger MPA cross sections than those of undoped CDs.
Giant Thickness‐Tunable Bandgap and Robust Air Stability of 2D Palladium Diselenide
Authors: Xie Chunyu , Jiang Shaolong , Gao Yinlu , Hong Min , Pan Shuangyuan , Zhao Jijun , Zhang Yanfeng 
Published: April 2020

AbstractUncovering the thickness‐dependent electronic property and environmental stability for 2D materials are crucial issues for promoting their applications in high‐performance electronic and optoelectronic devices. Herein, the extrahigh air stability and giant tunable electronic bandgap of chemical vapor deposition (CVD)–derived few‐layer PdSe2 on Au foils, by using scanning tunneling microscope/spectroscopy (STM/STS), are reported. The robust stability of 2D PdSe2 is uncovered by the observation of nearly defect/adsorption‐free atomic lattices on long‐time air‐exposed samples. A one‐to‐one correspondence between the electronic bandgap (from ≈1.15 to ≈0 eV) and thickness of PdSe2/Au (from bilayer to bulk) is established. It is also revealed that few‐layer semiconducting PdSe2 flakes present zero‐gap edges, induced by hybridization of Pd 4d and Se 4p orbitals. This work hereby provides straightforward evidence for the thickness‐tunable electronic property and air stability of 2D semiconductors, thus shedding light on their applications in next‐generation electronic devices.
Springtail‐Inspired Superamphiphobic Ordered Nanohoodoo Arrays with Quasi‐Doubly Reentrant Structures
Authors: Dong Shilian , Zhang Xiaolei , Li Qian , Liu Chuandong , Ye Tianyu , Liu Jiangchao , Xu Hang , Zhang Xingang , Liu Jing , Jiang Changzhong , Xue Longjian , Yang Shikuan , Xiao Xiangheng 
Published: April 2020

AbstractThe skin of springtails is well‐known for being able to repel water and organic liquids using their hexagonally arranged protrusions with reentrant structures. Here, a method to prepare 100 nm‐sized nanohoodoo arrays with quasi‐doubly reentrant structures over square centimeters through combining the nanosphere lithography and the template‐protected selective reactive ion etching technique is demonstrated. The top size of the nanohoodoos, the intra‐nanohoodoo distance, and the height of the nanohoodoos can be readily controlled by the plasma‐etching time of the polystyrene (PS) spheres, the size of the PS spheres used, and the reactive ion etching time of silicon. The strong structural control capability allows for the study of the relationship between the nanohoodoo structure and the wetting property. Superamphiphobic nanohoodoo arrays with outstanding water/organic liquid repellent properties are finally obtained. The superamphiphobic and liquid repellent properties endow the nanohoodoo arrays with remarkable self‐cleaning performance even using hot water droplets, anti‐fogging performance, and the surface‐enhanced Raman scattering sensitivity improvement by enriching the analyte molecules on the nanohoodoo arrays. Overall, the simple and massive production of the superamphiphobic nanohoodoo structures will push their practical application processes in diverse fields where wettability and liquid repellency need to be carefully engineered.