bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of novel pregnane-based 20-carboxamides via palladium-catalysed aminocarbonylation
Authors: Mikle Gábor , Zugó Alexandra , Szatnik Erzsébet , Maxim Anita , Mahó Sándor , Kollár László 
Published: January 2021

Abstract20-Carboxamidopregnene derivatives, such as 3β-acetoxy-5α-pregn-20-ene-20-carboxamides and 5α-pregn-20-ene-20-carboxamides were synthesized from the widely accessible 3β-acetoxy-pregn-5,16-dien-20-one (PDA) using selective hydrogenation, hydrazine and iodoalkene formation, as well as palladium-catalysed aminocarbonylation. The 20-iodo-20-ene derivatives, obtained from the corresponding 20-keto derivatives via their hydrazones, served as substrates. 23 new 20-carboxamides were obtained using variousN-nucleophiles ranging from simple primary amines to α-amino acid esters. The novelty of this methodology lies in the application of facile, moderate or high-yielding reactions to obtain otherwise hardly accessible steroidal 20-carboxamides of pharmaceutical importance. In other words, instead of the enzymatic or synthetic degradation of e.g., sterols or cholanic acids, functionalization of the basic skeleton (a ‘building-up’ approach) was used.
The role of managerial characteristics in FX risk management: Who increases risk?
Authors: Hecht Andreas 
Published: January 2021

AbstractWe examine the impact of managerial characteristics on the choice of risk-decreasing and risk-increasing/-constant strategies. Using unique data on firm-, year-, and currency-specific FX exposure before and after hedging with corresponding hedging instruments, we are able to measure how much a CEO has been involved in risk-increasing/-constant strategies over several years. We provide evidence that firms where the CEO has an MBA degree and is older are more likely to engage in risk-increasing/-constant strategies. In addition, we find that a CEO’s affiliation to the owner’s family seems to reduce the amount of derivatives a firms uses, while hedging short tends to increase derivative volumes.
The Use of Platelet-Rich Plasma (PRP) for the Management of Non-union Fractures
Authors: Andersen Christian , Wragg Nicholas M. , Shariatzadeh Maryam , Wilson Samantha Louise 
Published: January 2021

Abstract
Purpose of Review
The treatment of non-union fractures represents a significant challenge for orthopaedic surgeons. In recent years, biologic agents have been investigated and utilised to support and improve bone healing. Among these agents, platelet-rich plasma (PRP) is an emerging strategy that is gaining popularity. The aim of this review is to evaluate the current literature regarding the application and clinical effectiveness of PRP injections, specifically for the treatment of non-union fractures.

Recent Findings
The majority of published studies reported that PRP accelerated fracture healing; however, this evidence was predominantly level IV. The lack of randomised, clinical trials (level I–II evidence) is currently hampering the successful clinical translation of PRP as a therapy for non-union fractures. This is despite the positive reports regarding its potential to heal non-union fractures, when used in isolation or in combination with other forms of treatment.

Summary
Future recommendations to facilitate clinical translation and acceptance of PRP as a therapy include the need to investigate the effects of administering higher volumes of PRP (i.e. 5–20 mL) along with the requirement for more prolonged (> 11 months) randomised clinical trials.
Effects of Plastic Waste Materials on Geotechnical Properties of Clayey Soil
Authors: Hassan Hussein Jalal Aswad , Rasul Jabar , Samin Maleaha 
Published: January 2021

AbstractRecently, the use of plastic products, such as polyethylene (PE) bottles and polypropylene (PP), has been significantly increased, which may lead to many environmental issues. Therefore, it is important to find methods to manage these waste materials without causing any ecological hazards. One of these methods is to use plastic wastes as soil stabiliser materials. In this study, PE and PP have been used in the form of fibres. The effect of the stabilisation was evaluated through carrying out standard laboratory tests. These tests have been conducted on natural and stabilised soils with four fibre contents (1%, 2%, 3%, and 4%) of the soil weight. The tests included the standard compaction test, unconfined compressive strength (UCS) test, California Bearing Ratio (CBR) test, and resilient modulus (Mr) tests. In all these tests, the fibre content was added in two lengths, which were 1.0 cm and 2.0 cm. Laboratory test results revealed that the plastic pieces decrease maximum dry density (MDD) and optimum moisture content (OMC) of the stabilised soils, which are required for the construction of embankments of lightweight materials. In addition, there was a significant improvement in the UCS of soils by 76.4 and 96.6% for both lengths of PE fibres and 57.4% and 73.0% for both lengths of PP fibres, respectively. Results of the CBR tests demonstrated that the inclusion of plastic fibres in clayey soils improves the strength and deformation behaviour of the soil especially with 4% fibre content for both lengths 1.0 cm and 2.0 cm, respectively, to a figure of 185 to 150% for PE and PP, respectively. Furthermore, the results of the Mr tests demonstrated that the mechanical properties improved to an extent. For an increase in fibre content, the resilient modulus increased by about 120% at 4% fibre content for PE. However, for PP, improvement in resilient modulus declined at 3% fibre content. Therefore, for soil stabilisation with fibre material, optimum fibre content shall be sought.
A note on different types of product of neutrosophic graphs
Authors: Mohanta Kartick , Dey Arindam , Pal Anita 
Published: January 2021

AbstractFuzzy set and neutrosophic set are two efficient tools to handle the uncertainties and vagueness of any real-world problems. Neutrosophic set is more capable than fuzzy set to deal the uncertainties of a real-life problem. This research paper introduces some new concept of single-valued neutrosophic graph (SVNG). We have also presented some different operations on SVNG such as rejection, symmetric difference, maximal product, and residue product with appropriate examples, and some of their important theorems are also described. Then, we have described the concept of total degree of a neutrosophic graph with some interesting examples. We have also presented an efficient approach to solve a decision-making problem using SVNG.
Surrogate-assisted evolutionary algorithm for expensive constrained multi-objective discrete optimization problems
Authors: Gu Qinghua , Wang Qian , Xiong Neal N. , Jiang Song , Chen Lu 
Published: January 2021

AbstractSurrogate-assisted optimization has attracted much attention due to its superiority in solving expensive optimization problems. However, relatively little work has been dedicated to addressing expensive constrained multi-objective discrete optimization problems although there are many such problems in the real world. Hence, a surrogate-assisted evolutionary algorithm is proposed in this paper for this kind of problem. Specifically, random forest models are embedded in the framework of the evolutionary algorithm as surrogates to improve approximate accuracy for discrete optimization problems. To enhance the optimization efficiency, an improved stochastic ranking strategy based on the fitness mechanism and adaptive probability operator is presented, which also takes into account both convergence and diversity to advance the quality of candidate solutions. To validate the proposed algorithm, it is comprehensively compared with several well-known optimization algorithms on several benchmark problems. Numerical experiments are demonstrated that the proposed algorithm is very promising for the expensive constrained multi-objective discrete optimization problems.
Strategy and Future Prospects to Develop Room-Temperature-Recoverable NO2 Gas Sensor Based on Two-Dimensional Molybdenum Disulfide
Authors: Agrawal Abhay V. , Kumar Naveen , Kumar Mukesh 
Published: January 2021

AbstractNitrogen dioxide (NO2), a hazardous gas with acidic nature, is continuously being liberated in the atmosphere due to human activity. The NO2 sensors based on traditional materials have limitations of high-temperature requirements, slow recovery, and performance degradation under harsh environmental conditions. These limitations of traditional materials are forcing the scientific community to discover future alternative NO2 sensitive materials. Molybdenum disulfide (MoS2) has emerged as a potential candidate for developing next-generation NO2 gas sensors. MoS2 has a large surface area for NO2 molecules adsorption with controllable morphologies, facile integration with other materials and compatibility with internet of things (IoT) devices. The aim of this review is to provide a detailed overview of the fabrication of MoS2 chemiresistance sensors in terms of devices (resistor and transistor), layer thickness, morphology control, defect tailoring, heterostructure, metal nanoparticle doping, and through light illumination. Moreover, the experimental and theoretical aspects used in designing MoS2-based NO2 sensors are also discussed extensively. Finally, the review concludes the challenges and future perspectives to further enhance the gas-sensing performance of MoS2. Understanding and addressing these issues are expected to yield the development of highly reliable and industry standard chemiresistance NO2 gas sensors for environmental monitoring.
Solution-Processed Transparent Conducting Electrodes for Flexible Organic Solar Cells with 16.61% Efficiency
Authors: Wan Juanyong , Xia Yonggao , Fang Junfeng , Zhang Zhiguo , Xu Bingang , Wang Jinzhao , Ai Ling , Song Weijie , Hui Kwun Nam , Fan Xi , Li Yongfang 
Published: January 2021

AbstractNonfullerene organic solar cells (OSCs) have achieved breakthrough with pushing the efficiency exceeding 17%. While this shed light on OSC commercialization, high-performance flexible OSCs should be pursued through solution manufacturing. Herein, we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid (CF3SO3H). Through a low-concentration and low-temperature CF3SO3H doping, the conducting polymer anodes exhibited a main sheet resistance of 35 Ω sq−1 (minimum value: 32 Ω sq−1), a raised work function (≈ 5.0 eV), a superior wettability, and a high electrical stability. The high work function minimized the energy level mismatch among the anodes, hole-transporting layers and electron-donors of the active layers, thereby leading to an enhanced carrier extraction. The solution-processed flexible OSCs yielded a record-high efficiency of 16.41% (maximum value: 16.61%). Besides, the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85 °C, demonstrating a high flexibility and a good thermal stability.
Lotus Leaf-Derived Gradient Hierarchical Porous C/MoS2 Morphology Genetic Composites with Wideband and Tunable Electromagnetic Absorption Performance
Authors: Pan Fei , Liu Zhicheng , Deng Baiwen , Dong Yanyan , Zhu Xiaojie , Huang Chuang , Lu Wei 
Published: January 2021

AbstractInspired by the nature, lotus leaf-derived gradient hierarchical porous C/MoS2 morphology genetic composites (GHPCM) were successfully fabricated through an in situ strategy. The biological microstructure of lotus leaf was well preserved after treatment. Different pores with gradient pore sizes ranging from 300 to 5 μm were hierarchically distributed in the composites. In addition, the surface states of lotus leaf resulted in the Janus-like morphologies of MoS2. The GHPCM exhibit excellent electromagnetic wave absorption performance, with the minimum reflection loss of − 50.1 dB at a thickness of 2.4 mm and the maximum effective bandwidth of 6.0 GHz at a thickness of 2.2 mm. The outstanding performance could be attributed to the synergy of conductive loss, polarization loss, and impedance matching. In particularly, we provided a brand-new dielectric sum-quotient model to analyze the electromagnetic performance of the non-magnetic material system. It suggests that the specific sum and quotient of permittivity are the key to keep reflection loss below − 10 dB within a certain frequency range. Furthermore, based on the concept of material genetic engineering, the dielectric constant could be taken into account to seek for suitable materials with designable electromagnetic absorption performance.
Present and Future of Phase-Selectively Disordered Blue TiO2 for Energy and Society Sustainability
Authors: Luo Yongguang , Lee Hyoyoung 
Published: January 2021

AbstractTitanium dioxide (TiO2) has garnered attention for its promising photocatalytic activity, energy storage capability, low cost, high chemical stability, and nontoxicity. However, conventional TiO2 has low energy harvesting efficiency and charge separation ability, though the recently developed black TiO2 formed under high temperature or pressure has achieved elevated performance. The phase-selectively ordered/disordered blue TiO2 (BTO), which has visible-light absorption and efficient exciton disassociation, can be formed under normal pressure and temperature (NPT) conditions. This perspective article first discusses TiO2 materials development milestones and insights of the BTO structure and construction mechanism. Then, current applications of BTO and potential extensions are summarized and suggested, respectively, including hydrogen (H2) production, carbon dioxide (CO2) and nitrogen (N2) reduction, pollutant degradation, microbial disinfection, and energy storage. Last, future research prospects are proposed for BTO to advance energy and environmental sustainability by exploiting different strategies and aspects. The unique NPT-synthesized BTO can offer more societally beneficial applications if its potential is fully explored by the research community.
Hierarchical Magnetic Network Constructed by CoFe Nanoparticles Suspended Within “Tubes on Rods” Matrix Toward Enhanced Microwave Absorption
Authors: Xu Chunyang , Wang Lei , Li Xiao , Qian Xiang , Wu Zhengchen , You Wenbin , Pei Ke , Qin Gang , Zeng Qingwen , Yang Ziqi , Jin Chen , Che Renchao 
Published: January 2021

AbstractHierarchical magnetic-dielectric composites are promising functional materials with prospective applications in microwave absorption (MA) field. Herein, a three-dimension hierarchical “nanotubes on microrods,” core–shell magnetic metal–carbon composite is rationally constructed for the first time via a fast metal–organic frameworks-based ligand exchange strategy followed by a carbonization treatment with melamine. Abundant magnetic CoFe nanoparticles are embedded within one-dimensional graphitized carbon/carbon nanotubes supported on micro-scale Mo2N rod (Mo2N@CoFe@C/CNT), constructing a special multi-dimension hierarchical MA material. Ligand exchange reaction is found to determine the formation of hierarchical magnetic-dielectric composite, which is assembled by dielectric Mo2N as core and spatially dispersed CoFe nanoparticles within C/CNTs as shell. Mo2N@CoFe@C/CNT composites exhibit superior MA performance with maximum reflection loss of − 53.5 dB at 2 mm thickness and show a broad effective absorption bandwidth of 5.0 GHz. The Mo2N@CoFe@C/CNT composites hold the following advantages: (1) hierarchical core–shell structure offers plentiful of heterojunction interfaces and triggers interfacial polarization, (2) unique electronic migration/hop paths in the graphitized C/CNTs and Mo2N rod facilitate conductive loss, (3) highly dispersed magnetic CoFe nanoparticles within “tubes on rods” matrix build multi-scale magnetic coupling network and reinforce magnetic response capability, confirmed by the off-axis electron holography.
Laser Synthesis and Microfabrication of Micro/Nanostructured Materials Toward Energy Conversion and Storage
Authors: Zhao Lili , Liu Zhen , Chen Duo , Liu Fan , Yang Zhiyuan , Li Xiao , Yu Haohai , Liu Hong , Zhou Weijia 
Published: January 2021

AbstractNanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications, including energy conversion and storage, nanoscale electronics, sensors and actuators, photonics devices and even for biomedical purposes. In the past decade, laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction, including the laser processing-induced carbon and non-carbon nanomaterials, hierarchical structure construction, patterning, heteroatom doping, sputtering etching, and so on. The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices, such as light–thermal conversion, batteries, supercapacitors, sensor devices, actuators and electrocatalytic electrodes. Here, the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized. An extensive overview on laser-enabled electronic devices for various applications is depicted. With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies, laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
An Apple Extract Beverage Combined with Caffeine Can Improve Alertness, Mental Fatigue, and Information Processing Speed
Authors: Ward-Ritacco Christie L. , Wilson Alissa R. , O’Connor Patrick J. 
Published: January 2021

AbstractThe psychological effects of low-dose caffeine combined with polyphenols from apples have rarely been explored scientifically yet synergistic effects are plausible. A randomized, double-blind, placebo-controlled cross-over experiment was used to test the psychological effects of apple extract beverages combined with 10, 20, 37.5, and 75 mg caffeine. Comparisons were made to both a placebo drink that was artificially sweetened and colored to mimic the test beverages and a positive control drink with 75 mg caffeine but without apple extract. Compared to placebo, it was hypothesized that dose-dependent improvements in cognitive performance, mood, and motivation would be realized after consuming the beverage with apple extract containing added caffeine. Outcomes were assessed before, 60 to 110, and 125 to 175 min post-beverage. The positive control beverage resulted in more serial seven subtractions, greater motivation to perform cognitive tasks, and reduced feelings of fatigue (all p < .005). The study found that psychological effects (i) were not observed for beverages containing apple extract and 10 or 20 mg caffeine, (ii) of the apple extract beverage containing 75 mg caffeine generally mimicked the effects of the positive control drink and significantly increased serial seven processing speed, and (iii) of the apple extract beverage containing 37.5 mg improved feelings of alertness and mental fatigue. In sum, effects of apple extract combined with caffeine were not dose-dependent; the apple extract beverage containing 75 mg caffeine improved information processing speed and the apple extract beverage with 37.5 mg caffeine improved feelings of alertness and mental fatigue.
The First Cathedral on America’s Pacific Coast
Authors: Hernández Mora Iosvany , Martín Juan G. , Aram Bethany 
Published: January 2021

AbstractNew research dispels the idea that Panamá Viejo was initially founded one-half mile from the site of its visible present-day ruins. The archaeological and historical evidence, subjected to interdisciplinary analysis, demonstrates that the city remained on the same main plaza next to its natural port from its founding 500 years ago until its destruction in 1671. The data reconsidered and newly uncovered also suggest reasons for previous misinterpretations of the city’s early foundational history. Unlike many colonial cities and towns, Panamá Viejo did not move during its first century of existence. However, its main church, which became the bishopric’s cathedral in 1524, did relocate after 1541. The new evidence establishes and confirms the original location of the first cathedral on America’s Pacific Ocean to the south of Panamá Viejo’s main plaza and explains its move to an elevated, rocky area on the eastern side of the same plaza over 20 years later. Excavations undertaken in 2018 have confirmed the original building’s location a mere 50 m from the visible ruins of the cathedral, the tower of which remains a symbol of Panamanian identity today.
One-flow synthesis of tetrahydrocannabinol and cannabidiol using homo- and heterogeneous Lewis acids
Authors: Bloemendal Victor R. L. J. , Spierenburg Bram , Boltje Thomas J. , van Hest Jan C. M. , Rutjes Floris P. J. T. 
Published: January 2021

AbstractContinuous flow chemistry holds great potential for the production of biologically relevant molecules. Herein, we present an approach for the continuous synthesis of cannabidiol and tetrahydrocannabinol in a one-flow system. The designed route consists of a reaction cascade involving Friedel-Crafts alkylation, subsequent ring opening and cyclisation in up to 45% yield. The reactions were successfully performed using both hetero- and homogeneous Lewis acids in continuous flow and provide yields that are similar to comparable batch processes.Graphical abstract
A robust-filtering method for noisy non-stationary multivariate time series with econometric applications
Authors: Kunitomo Naoto , Sato Seisho 
Published: January 2021

AbstractWe investigate a new filtering method to estimate the hidden states of random variables for multiple non-stationary time series data. This helps in analyzing small sample non-stationary macro-economic time series in particular and it is based on the frequency domain application of the separating information maximum likelihood (SIML) method, developed by Kunitomo et al. (Separating Information Maximum Likelihood Estimation for High Frequency Financial Data. Springer, New York, 2018), and Kunitomo et al. (Japan J Statistics Data Sci 2:73–101, 2020), and Nishimura et al. (Asic-Pacific Financial Markets, 2019). We solve the filtering problem of hidden random variables of trend-cycle, seasonal and measurement-errors components, and propose a method to handle macro-economic time series. We develop the asymptotic theory based on the frequency domain analysis for non-stationary time series. We illustrate applications, including some properties of the method of Müller and Watson (Econometrica 86-3:775–804, 2018), and analyses of some macro-economic data in Japan.