bluuebunny/crossref_metadata_2025_split huggingface dataset:
Realizing the Capability of Negatively Charged Graphene Oxide in the Presence of Conducting Polyaniline for Performance Enhancement of Tribopositive Material of Triboelectric Nanogenerator
Authors: Ahmad Rafi u Shan , Haleem Abdul , Haider Zeeshan , Claver Uzabakiriho Pierre , Fareed Azam , Khan Irfan , Mbogba Momoh Karmah , Memon Kashan , Ali Wajahat , He Weidong , Hu Peng , Zhao Gang 
Published: April 2020

AbstractIn recent years, tremendous efforts have been made to investigate tribomaterials for triboelectric nanogenerators (TENGs), but due to their low performance there is still need of tribomaterials with new mechanisms for performance enhancement. Therefore, in this study, the potential of conducting polyaniline and tribonegative graphene oxide is exploited for performance enhancement of tribopositive material through a new mechanism of disturbing the equilibrium state inside the tribopositive material under an impact force. Thus, a TENG device made up of polymer with 700 µL polyaniline and 4 mg mL−1 graphene oxide as tribopositive and polydimethylsiloxane as a tribonegative layer with a dimension of 1 × 2 cm2 is able to produce an open‐circuit voltage of 314.92 V and a current density of 37.81 mA m−2 with a peak power density of 10.43 W m−2, which can directly power ON more than 175 white light‐emitting diodes. Amine group of polyaniline and its pathway to mobilize electrons inside the tribopositive material due to electron accepting ability of graphene oxide upon physical contact under external force are the main contributing factors toward performance enhancement. This work introduces a low cost, easy fabrication process with a new method for performance enhancement of tribopositive material to acquire a high performance TENGs.
Exploiting Flexible Memristors Based on Solution‐Processed Colloidal CuInSe2 Nanocrystals
Authors: Guo Ruiqi , Zhang Linxing , Meng Jie , Liu Aqiang , Yuan Jifeng , Zheng Kaibo , Tian Jianjun 
Published: April 2020

AbstractCompared to analogous bulk materials, colloidal nanocrystals have presented a powerful platform for building up electronic devices on the nano/micrometer scale and flexible portable electronic apparatus with the benefits of solution‐based processing approach at room temperature. Herein, memristors based on CuInSe2 (CISe) colloidal nanocrystals prepared using a solution‐based process at room temperature are constructed. The memristors exhibit obvious bipolar resistive switching performance with a high–low resistance ratio larger than 5.7 and a steady retention time over 104 s. This is attributed to the copper ion redox reaction and the migration of these ions under an applied electric field. When the SET voltage is reached, the ions are separated from one of the electrodes, and the memristor changes from a low‐resistance state (LRS) to a high‐resistance state (HRS). Conversely, when the voltage reaches the RESET voltage, the memristor switches from a HRS to a LRS. In addition, the flexible memristor can be fabricated by spincoating nanocrystal solution onto polyethylene terephthalate (PET) at room temperature, showing excellent reproducibility of the performance including 100 times of continuous operation, 104 s of reproducible reading, 600 times of antifatigue testing, and thermal stability up to 95 °C. The flexible devices demonstrate promising applications for portable electronic devices.
Realizing Excellent n‐ and p‐Type Niobium‐Based Half‐Heusler Compounds Based on Thermoelectric Properties and High‐Temperature Stability
Authors: Silpawilawan Wanthana , Tanuslip Sora‐at , Chetty Raju , Ohta Michihiro , Ohishi Yuji , Muta Hiroaki , Kurosaki Ken 
Published: April 2020

AbstractHalf‐Heusler (HH) compounds are currently promising thermoelectric (TE) materials due to their outstanding performance. For reliable n‐ and p‐type HH compounds, the dimensionless figure of merit zT is reported as greater than unity. However, to develop a high‐performance TE module, zT, high‐temperature stability, and compatibility of n‐ and p‐type materials are key parameters. Here, the TE and thermomechanical properties and the high‐temperature stability of Nb‐based HH compounds: n‐type Nb0.75M0.1CoSb and p‐type FeNb0.9M0.1Sb (M = Ti, Zr, Hf) are investigated. The results reveal that the Ti‐doped system exhibits better TE and thermomechanical properties than the Zr‐ and Hf‐doped systems. Furthermore, the Ti‐doped samples show good high‐temperature stability in an inert atmosphere up to 773 K and in air up to 673 K. The performance of a 2π‐module based on the best n‐type Nb0.75Ti0.1CoSb and p‐type FeNb0.9Ti0.1Sb is simulated by using the 3D finite element method. The maximum output power density (ωmax) and conversion efficiency (ηmax) of 2.3 W cm−2 and 4.0%, respectively, are obtained when the cold‐ and hot‐side temperatures are 298 and 773 K, respectively.
Topological Hall Effect in Single Thick SrRuO3 Layers Induced by Defect Engineering
Authors: Wang Changan , Chang Ching‐Hao , Herklotz Andreas , Chen Chao , Ganss Fabian , Kentsch Ulrich , Chen Deyang , Gao Xingsen , Zeng Yu‐Jia , Hellwig Olav , Helm Manfred , Gemming Sibylle , Chu Ying‐Hao , Zhou Shengqiang 
Published: April 2020

AbstractThe topological Hall effect (THE) has been discovered in ultrathin SrRuO3 (SRO) films, where the interface between the SRO layer and another oxide layer breaks the inversion symmetry resulting in the appearance of THE. Thus, THE only occurs in ultrathin SRO films of several unit cells. In addition to employing a heterostructure, the inversion symmetry can be broken intrinsically in bulk SRO by introducing defects. In this study, THE is observed in 60‐nm‐thick SRO films, in which defects and lattice distortions are introduced by helium ion irradiation. The irradiated SRO films exhibit a pronounced THE in a wide temperature range from 5 to 80 K. These observations can be attributed to the emergence of Dzyaloshinskii–Moriya interaction as a result of artificial inversion symmetry breaking associated with the lattice defect engineering. The creation and control of the THE in oxide single layers can be realized by ex situ film processing. Therefore, this work provides new insights into the THE and illustrates a promising strategy to design novel spintronic devices.
The Journey toward Low Temperature, Low Pressure Catalytic Nitrogen Fixation
Authors: Shi Run , Zhang Xuerui , Waterhouse Geoffrey I. N. , Zhao Yunxuan , Zhang Tierui 
Published: April 2020

AbstractAmmonia and its derived products are vital to modern societies. Artificial nitrogen fixation to ammonia via the Haber–Bosch process has been employed industrially for over 100 years. However, the Haber–Bosch process is energy intensive and not sustainable in its current form as it uses hydrogen sourced from steam methane reforming to reduce N2. The roadmap to sustainable NH3 production demands the discovery of novel approaches for nitrogen fixation under near ambient conditions that preferably use water as the reducing agent. Over the last decade, great efforts have been made to develop catalysts capable of N2 fixation under mild reaction conditions, using strategies such as low temperature thermal catalysis, nonthermal plasma catalysis, enzymatic catalysis, photocatalysis, and electrocatalysis to generate ammonia and other valuable nitrogen‐containing chemicals. In parallel with catalytic performance studies, researchers have also placed emphasis on the mechanistic understanding of natural and artificial nitrogen fixation catalysts. In this work, the various routes now being explored for nitrogen fixation are summarized. The different dinitrogen activation and hydrogenation pathways are described, whilst describing key advances made to date on the journey toward near ambient ammonia synthesis. Key obstacles that need to be overcome to attract industry interest are also discussed.
Recent Advances in Photoredox Methods for Ketone Synthesis
Authors: Chalotra Neha , Sultan Shaista , Shah Bhahwal Ali 
Published: April 2020

AbstractSynthesis of ketones is one of the most addressed problems in organic chemistry owing to their presence in a diverse array of drugs, pharmaceuticals, natural products and photosensitizers. Many of the limitations associated with the traditional approaches enabling the synthesis of ketones like creation of high energy acylating reagents, poor functional group tolerance, pre‐activation of starting materials have been largely addressed with the advent of photoredox chemistry. This review summarizes the recent advances made in the photoredox catalyzed synthesis of ketones.
Hydrosulfonylation of Alkenes with Sulfonyl Chlorides under Visible Light Activation
Authors: Hell Sandrine M. , Meyer Claudio F. , Misale Antonio , Sap Jeroen B. I. , Christensen Kirsten E. , Willis Michael C. , Trabanco Andrés A. , Gouverneur Véronique 
Published: April 2020

AbstractSulfonyl chlorides are inexpensive reactants extensively explored for functionalization, but never considered for radical hydrosulfonylation of alkenes. Herein, we report that tris(trimethylsilyl)silane is an ideal hydrogen atom donor enabling highly effective photoredox‐catalyzed hydrosulfonylation of electron‐deficient alkenes with sulfonyl chlorides. To increase the generality of this transformation, polarity‐reversal catalysis (PRC) was successfully implemented for alkenes bearing alkyl substituents. This late‐stage functionalization method tolerates a remarkably wide range of functional groups, is operationally simple, scalable, and allows access to building blocks which are important for medicinal chemistry and drug discovery.
Oxidative Addition of Dihydrogen to Divanadium in Solid Ne: Multiple‐Bonded Triplet HVVH and Singlet V2(μ‐H)2
Authors: Hübner Olaf , Himmel Hans‐Jörg 
Published: April 2020

AbstractDinuclear compounds of early transition metals with a high metal–metal bond order are of fundamental interest due to their intriguing bonding situation and of practical interest because of their potential involvement in catalytic processes. In this work, two isomers of V2H2 have been generated in solid Ne by the reaction between V2 and H2 and detected by infrared spectroscopy: the linear HVVH molecule (3Σg− ground state), which is the product of the spin‐allowed reaction between V2 (3Σg− ground state) and H2, and a lower‐energy, folded V2(μ‐H)2 isomer (1A1 ground state) with two bridging hydrogen atoms. Both isomers are characterized by metal–metal bonding with a high bond order; the orbital occupations point to quadruple bonding. Irradiation with ultraviolet light induces the transformation of linear HVVH to folded V2(μ‐H)2, whereas irradiation with visible light initiates the reverse reaction.
Accumulation of 2‐tert‐Butyl‐1,4‐Benzoquinone in Frying Oil and Fried Food during Repeated Deep Fat Frying Processes
Authors: Ye Qin , Xia Chaosheng , Nie Xiaohua , Meng Xianghe 
Published: April 2020

Abstract2‐tert‐Butyl‐1,4‐benzoquinone (TBBQ), the main oxidation product of tert‐butyl‐hydroquinone (TBHQ) during frying, is cytotoxic and its residual levels in frying oils and foods are unknown. In this study, TBBQ residues have been evaluated during the preparation of french fries. Results showed that frying at 140 °C resulted in the highest TBBQ peak concentration (48.42 mg kg−1) compared with frying at 190 or 170 °C. This unexpected finding can be attributed to more extensive hydrolytic reaction when frying at the lower temperature, generating more peroxyl radicals. TBBQ concentrations proved to be independent of the oil type among various unsaturated oils. However, higher TBBQ levels were observed in saturated palm oil and crude soybean oil than in unsaturated oil or refined oil. Continuous frying leads to the accumulation of a large amount of TBBQ in fried food. After frying 1–5 batches, TBBQ levels in both the frying oil and fries were above 10 mg kg−1, exceeding its critical cytotoxic concentration (IC50 value of 10.71 mg kg−1 for RAW 246.7 cells in our previous study), warranting concern with respect to the safety of fried food. FTIR has been utilized as an effective tool for visually monitoring the degree of oxidation in the frying medium with respect to its hydrogen peroxide level, which contributes to the increased level of TBBQ derived from TBHQ therein.
Constituent diversity of ethanol extracts from pitaya
Authors: Ma Jinghua , Mo Wei , Zhang Pangpan , Lai Yong , Li Ximei , Zhang Dangquan 
Published: April 2020

AbstractPitaya is rich in nutrition and unique in function and contains vegetable albumin, anthocyanins, rich vitamins, and water soluble dietary fiber, which are rare in fruits and vegetables. However, researches mostly focused on pitaya cultivation, biological characteristics, fresh‐keeping, and lacked analyses about chemical composition of pitaya. Therefore, ethanol extraction and GC/MS were used to extract and identify the bioactive components in pulp and pericarp of red pitaya and white pitaya. The extracting results showed that percentages of ethanol extracts from pulp and pericarp of red pitaya were 14.5% and 12%, whereas those of white pitaya were 16% and 12%. The GC/MS results showed that different kinds of bioactive constituents were identified in fresh pericarp and pulp of red pitaya and white pitaya. In the four ethanol extracts, there are rich polysiloxane plant organosilicon with total contents of 10.09%, 24.21%, 25.77%, and 23.25%. Meanwhile, there are many heterocyclic substances, and the content of pericarp is much higher than that of pulp. The four ethanol extracts also contain some other bioactive ingredients, such as esters, hydrocarbons, alcohols, amides, halides, and fatty acids, which can be used as raw materials for biomedicine, advanced cosmetics, and skin care products.
Sulfonamides incorporating ketene N,S‐acetal bioisosteres as potent carbonic anhydrase and acetylcholinesterase inhibitors
Authors: Istrefi Qëndresa , Türkeş Cüneyt , Arslan Mustafa , Demir Yeliz , Nixha Arleta R. , Beydemir Şükrü , Küfrevioğlu Ömer İ. 
Published: April 2020

AbstractIn this study, 15 novel compounds in a series of sulfonamide‐based ketenes (7a–o) were synthesized and characterized using Fourier‐transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass spectrometry. All compounds were tested for their ability to inhibit the human carbonic anhydrase (hCA) isoforms I and II, and acetylcholinesterase (AChE). The halogen‐appended compounds, 7g, 7o, and 7i, exhibited the highest hCA I/II and AChE inhibition, with the KI values in the low nanomolar range (KI = 9.01 ± 0.08, 7.41 ± 0.03, and 7.37 ± 0.31 nM, respectively), as compared with their corresponding parent 2‐[2,2‐dicyano‐1‐(phenylamino)vinylthio]‐N‐(4‐sulfamoylphenyl)acetamide analogs 7a–o. Besides, derivatives 7c and 7e selectively inhibited the isoform hCA I, whereas compounds 7m and 7n selectively inhibited isoform hCA II. These findings indicated that all compounds can inhibit metabolic dysfunctions, such as edema, epilepsy, glaucoma, and Alzheimer's disease, by specifically targeting both the hCA isoforms and AChE expression. Herein, also the interactions between ligands and receptors were highlighted through in silico molecular docking studies. The molecular mechanics–generalized Born surface area method was utilized to compute the binding free energy and the energy contribution of the critical residues in the active site was estimated. All these results would help us to perfectly understand the relationship between activity and structural characteristics of derivatives and to further improve newly and highly effective analogs targeting hCA and AChE.
Substituted adamantylphthalimides: Synthesis, antiviral and antiproliferative activity
Authors: Mandić Leo , Benčić Patricia , Mlinarić‐Majerski Kata , Liekens Sandra , Snoeck Robert , Andrei Graciela , Kralj Marijeta , Basarić Nikola 
Published: April 2020

AbstractIn this study, three groups of adamantylphthalimides, bearing different substituents at the phthalimide moiety, N‐(4′‐R2)phthalimidoadamantanes (1–7), 3‐[N‐(4′‐R2)phthalimido]‐1‐adamantanols (8–10), and 3‐[N‐(4′‐R2)phthalimido]adamantane‐1‐carboxylic acids (11–15), were synthesized and screened against tumor cells and viruses. The most potent compounds are not substituted at the adamantane and bear an OH or NH2 substituent at the phthalimide (compounds 3 and 5). The antiproliferative activities of compounds 3 and 5 are in the micromolar range, much higher than the one of thalidomide. A minor antiviral activity against cytomegalovirus and varicella‐zoster virus was found for compounds 3 and 5, but these compounds lacked selectivity. The results presented are important for the rational design of the next‐generation compounds with anticancer and antiviral activities.
Online Assessment of Applied Anatomy Knowledge: The Effect of Images on Medical Students' Performance
Authors: Sagoo Mandeep Gill , Vorstenbosch Marc A.T.M. , Bazira Peter J. , Ellis Harold , Kambouri Maria , Owen Charlie 
Published: April 2020

Anatomical examinations have been designed to assess topographical and/or applied knowledge of anatomy with or without the inclusion of visual resources such as cadaveric specimens or images, radiological images, and/or clinical photographs. Multimedia learning theories have advanced the understanding of how words and images are processed during learning. However, the evidence of the impact of including anatomical and radiological images within written assessments is sparse. This study investigates the impact of including images within clinically oriented single‐best‐answer questions on students' scores in a tailored online tool. Second‐year medical students (n = 174) from six schools in the United Kingdom participated voluntarily in the examination, and 55 students provided free‐text comments which were thematically analyzed. All questions were categorized as to whether their stimulus format was purely textual or included an associated image. The type (anatomical and radiological image) and deep structure of images (question referring to a bone or soft tissue on the image) were taken into consideration. Students scored significantly better on questions with images compared to questions without images (P < 0.001), and on questions referring to bones than to soft tissue (P < 0.001), but no difference was found in their performance on anatomical and radiological image questions. The coding highlighted areas of “test applicability” and “challenges faced by the students.” In conclusion, images are critical in medical practice for investigating a patient's anatomy, and this study sets out a way to understand the effects of images on students' performance and their views in commonly employed written assessments.
Validity and accuracy of the Adult Attention‐Deficit/Hyperactivity Disorder (ADHD) Self‐Report Scale (ASRS) and the Wender Utah Rating Scale (WURS) symptom checklists in discriminating between adults with and without ADHD
Authors: Brevik Erlend Joramo , Lundervold Astri J. , Haavik Jan , Posserud Maj‐Britt 
Published: April 2020

AbstractObjectiveTo validate the Adult ADHD Self‐Report Scale (ASRS) and the Wender Utah Rating Scale (WURS) in a well‐characterized sample of adult attention‐deficit/hyperactivity disorder (ADHD) patients and population controls.MethodsBoth the ASRS and the WURS were administered to clinically diagnosed adult ADHD patients (n = 646) and to population controls (n = 908). We performed principal component analyses (PCA) and calculated receiver operating curves (ROC) including area under the curve (AUC) for the full WURS and ASRS, as well as for the PCA generated factors and the ASRS short screener.ResultsWe found an AUC of 0.956 (95% CI: 0.946–0.965) for the WURS, and 0.904 (95% CI: 0.888–0.921) for the ASRS. The ASRS short screener had an AUC of 0.903 (95%CI: 0.886–0.920). Combining the two full scales gave an AUC of 0.964 (95% CI: 0.955–0.973). We replicated the two‐factor structure of the ASRS and found a three‐factor model for the WURS.ConclusionThe WURS and the ASRS both have high diagnostic accuracy. The short ASRS screener performed equally well as the full ASRS, whereas the WURS had the best discriminatory properties. The increased diagnostic accuracy may be due to the wider symptom range of the WURS and/or the retrospective childhood frame of symptoms.
Corporate carbon risk exposure, voluntary disclosure, and financial reporting quality
Authors: Lemma Tesfaye T. , Shabestari Mehrzad Azmi , Freedman Martin , Mlilo Mthokozisi 
Published: April 2020

AbstractThe study examines whether corporate carbon risk exposure is associated with financial reporting quality and whether voluntary carbon disclosure mediates the relationship. We analyze data drawn from firms traded on the Johannesburg Stock Exchange (JSE), for the period 2011 to 2015. We document robust evidence that firms with higher carbon risk exposure tend to provide financial statements of poorer quality (i.e., direct effect) and this association is partially mediated through voluntary carbon disclosure (i.e., indirect effect). The overall negative association between corporate carbon risk exposure and the firm's financial reporting quality is partly explained by the quality of voluntary carbon disclosure.
Feasibility study on machine‐learning‐based hybrid renewable energy applications for engineering education
Authors: Chandrasekaran Shilaja 
Published: April 2020

AbstractIn addition to the conventional natural resources such as petroleum extracts, natural gas and charcoal, and particularly with the current worldwide condition of economy of the energy sector, renewable energy sources are increasingly gaining attention. On the basis of recent researches, experts and environmentalists suggest that the renewable energy sources contribute for the major energy consumption. Rapid development of the renewable energy and energy‐efficient technologies results in significant energy security and economic benefits, which lead to reduction in capital investment for electricity systems. Therefore, through power system planning, we can augment the quality and efficiency of the power supply. The challenges in meeting the power requirements can be addressed by machine learning (ML) technique, an interdisciplinary field that allows using the statistical techniques to solve the energy‐related problems using pattern recognition, artificial neural network, and fuzzy and hybrid combinations. The recent innovations in web‐based and mobile technologies led to the application of ML in energy sector.