bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of hydrophobically modified PEO polymers (PEO-dodecyl) on oil/water microemulsion properties: in vitro and in silico investigations
Authors: Khatouri M. , Ahfir R. , Lemaalam M. , El Khaoui S. , Derouiche A. , Filali M.
Published: February 2021

In this work, we study the effect of grafted PEO-dodecyl co-polymers on the decane/water microemulsions properties. For this purpose, we combined the MD simulations, the OZ integral equations resolved using the HNC closure, and SANS experiments.
Current advances in nanomaterials affecting morphology, structure, and function of erythrocytes
Authors: Tian Yaxian , Tian Zhaoju , Dong Yanrong , Wang Xiaohui , Zhan Linsheng
Published: February 2021

This review focuses on the way how nanoparticles affect the structure and function of erythrocyte membranes, and is expected to pave the way for development of new nanodrugs.
Construction of a ratio fluorescence assay of 5-aminosalicylic acid based on its aggregation induced emission with blue emitting N/P-codoped carbon dots
Authors: Hu Yingying , Wang Yongping , Guan Rentian , Zhang Cong , Shao Xiaodong , Yue Qiaoli
Published: February 2021

Herein, a novel ratio fluorescence method based on N/P-doped carbon dots (NPCDs) for detecting 5-aminosalicylic acid (5-ASA) in mesalazine enteric coated tablets and blood were reported for the first time.
Microphase separation/crosslinking competition-based ternary microstructure evolution of poly(ether-b-amide)
Authors: Wang Yu , Wang Zefan , Zhu Ping , Liu Xinran , Wang Lei , Dong Xia , Wang Dujin
Published: February 2021

The temperature dependence of the rheological properties of poly(ether-b-amide) (PEBA) segmented copolymer under oscillatory shear flow has been investigated.
Synthetic strategies for aryl/heterocyclic selenides and tellurides under transition-metal-catalyst free conditions
Authors: Kundu Debasish
Published: February 2021

Synthesis of aryl and heteroaryl selenides and tellurides are summerized under transition free sustainable conditions by using greener reagents and techniques such as ball milling, microwave heating, ultrasound, visible light photocatalysis etc.
A modified random network model for P2O5–Na2O–Al2O3–SiO2 glass studied by molecular dynamics simulations
Authors: Zhao Yaxian , Du Jincheng , Cao Xin , Zhang Chong , Xu Gang , Qiao Xvsheng , Liu Yong , Peng Shou , Han Gaorong
Published: February 2021

(A) A modified structural model proposed for P2O5-bearing sodium aluminosilicate glasses. (B) Degree of preferred connection (DPC) of different T–O–T network linkage for LAP, MAP and HAP glass compositions with various P2O5 content.
Versatile one-pot synthesis of gold nanoclusters and nanoparticles using 3,6-(dipyridin-2-yl)-(1,2,4,5)-tetrazine
Authors: Rus Yahdi Bin , Bosmi Margarita , Maisonneuve Stéphane , Guérineau Vincent , Noël Vincent , Courty Alexa , Miomandre Fabien
Published: February 2021

Easy synthesis of gold nanoclusters stabilized by thiols and tetrazines.
Revealing the role of excited state proton transfer (ESPT) in excited state hydrogen transfer (ESHT): systematic study in phenol–(NH3)n clusters
Authors: Jouvet Christophe , Miyazaki Mitsuhiko , Fujii Masaaki
Published: February 2021

A general model of excited state hydrogen transfer (ESHT) which unifies ESHT and the excited state proton transfer (ESPT) is presented from experimental and theoretical works on phenol–(NH3)n. The hidden role of ESPT is revealed.
Hexafluoroisopropanol: the magical solvent for Pd-catalyzed C–H activation
Authors: Bhattacharya Trisha , Ghosh Animesh , Maiti Debabrata
Published: February 2021

Among numerous solvents available for chemical transformations, 1,1,1,3,3,3-hexafluoro-2-propanol (popularly known as HFIP) has attracted enough attention of the scientific community in recent years.
A 3D oriented CuS/Cu2O/Cu nanowire photocathode
Authors: He Xuefeng , Chen Xin , Chen Rong , Zhu Xun , Liao Qiang , Ye Dingding , Yu Youxu , Zhang Wei , Li Jinwang
Published: February 2021

The novelty of the work: a 3D oriented CuS/Cu2O/Cu nanowire photocathode on copper foam toward the oxygen reduction reaction for a photocatalytic fuel cell.
Core–shell-structured CNT@hydrous RuO2 as a H2/CO2 fuel cell cathode catalyst to promote CO2 methanation and generate electricity
Authors: Hu Jixiang , Qu Ting , Liu Yan , Dai Xin , Tan Qiang , Chen Yuanzhen , Guo Shengwu , Liu Yongning
Published: February 2021

Core–shell-structured CNT@hydrous RuO2 as the H2/CO2 fuel cell cathode catalyst promotes CO2 methanation.
Efficient and stable deep blue thermally activated delayed fluorescent molecules based on a bipyridine acceptor core
Authors: Cheng Cong , Jiang Yongshi , Wang Haonan , Lou Weiwei , Zhu Yunhui , Deng Chao , Wang Dan , Tsuboi Taiju , Li Guijie , Zhang Qisheng
Published: February 2021

Blue thermally activated delayed fluorescence emitters with a compact “donors-surrounding-acceptor” structure exhibit high stability in both photoluminescence and electroluminescence.
MnO2 nanoflowers as a multifunctional nano-platform for enhanced photothermal/photodynamic therapy and MR imaging
Authors: Sun Wanru , Yu Hui , Wang Deqiang , Li Youjie , Tian Baocheng , Zhu Shuang , Wang Ping-Yu , Xie Shuyang , Wang Ranran
Published: February 2021

Well-defined flower-shaped manganese oxide nanoparticles modified with 3-aminopropyltriethoxysilane (APTES) and loaded with Ce6 were achieved to realize synergistic PDT/PTT therapy and MR imaging.
Interfacial cationization to quicken redox-responsive drug release
Authors: Zheng Yaxin , Lei Jie , Li Qi , Jin Xuan , Li Qingyuan , Li Yang
Published: February 2021

Interfacial cationization increases redox-responsiveness of nanocarriers to accelerate intracellular drug release by generating and adsorbing ionized thiols at interfaces.
Nanoscopic morphological effect on the optical properties of polymer-grafted gold polyhedra
Authors: Lee Jaedeok , Bae Cheongwon , Ou Zihao , Park Suhyeon , Kim Jeongeon , Kim Juyeong
Published: February 2021

We investigate a series of polymer-grafted polyhedral gold nanoparticles to find a correlation between localised surface plasmon resonance features and nanoscopic morphology details of the polyhedral core under the influence of the polymeric shell.
Effect of poly(diallyldimethylammonium chloride) adsorption on the dispersion features of SiC particles in aqueous media
Authors: Niu Yifan , Zhang Wenxiao , Zhai Chaoyang , Liu Jiaxiang
Published: February 2021

The dispersion behavior of SiC suspensions was improved by PDADMAC adsorbed on the SiC surface effectively through electrostatic interaction.
Interfacial chemistry in anode-free batteries: challenges and strategies
Authors: Tong Zizheng , Bazri Behrouz , Hu Shu-Fen , Liu Ru-Shi
Published: February 2021

Interfacial engineering strategies in the anode-free battery.
Unusual ring D fixation by three crucial residues promotes phycoviolobilin formation in the DXCF-type cyanobacteriochrome without the second Cys
Authors: Fushimi Keiji , Narikawa Rei
Published: February 2021

Cyanobacteriochromes are linear tetrapyrrole-binding photoreceptors produced by cyanobacteria. Their chromophore-binding GAF domains are categorized into many lineages. Among them, dual Cys-type cyanobacteriochrome GAF domains possessing not only a highly conserved ‘first Cys' but also a ‘second Cys' are found from multiple lineages. The first Cys stably attaches to C31 of the A-ring, while the second Cys mostly shows reversible ligation to the C10 of the chromophore. Notably, the position of the second Cys in the primary sequence is diversified, and the most abundant dual Cys-type GAF domains have a ‘second Cys' within the DXCF motif, which are called DXCF GAF domains. It has been long known that the second Cys in the DXCF GAF domains not only shows the reversible ligation but also is involved in isomerization activity (reduction in C4=C5 double bond) from the initially incorporated phycocyanobilin to phycoviolobilin. However, comprehensive site-directed mutagenesis on the DXCF GAF domains, AM1_6305g1 and AM1_1499g1, revealed that the second Cys is dispensable for isomerization activity, in which three residues participate by fixing the C- and D-rings. Fixation of the chromophore on both sides of the C5 bridge is necessary, even though one side of the fixation site is far from this bridge, with the other side at C31 fixed by the first Cys.
HMGB1 regulates ferroptosis through Nrf2 pathway in mesangial cells in response to high glucose
Authors: Wu You , Zhao Ying , Yang Han-ze , Wang Yan-jun , Chen Yan
Published: February 2021

Ferroptosis, a novel type of programmed cell death, is involved in inflammation and oxidation of various human diseases, including diabetic kidney disease. The present study explored the role of high-mobility group box-1 (HMGB1) on the regulation of ferroptosis in mesangial cells in response to high glucose. Compared with healthy control, levels of serum ferritin, lactate dehydrogenase (LDH), reactive oxygen species (ROS), malonaldehyde (MDA), and HMGB1 were significantly elevated in diabetic nephropathy (DN) patients, accompanied with deregulated ferroptosis-related molecules, including long-chain acyl-CoA synthetase 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (PTGS2), NADPH oxidase 1 (NOX1), and glutathione peroxidase 4 (GPX4). In vitro assay revealed that erastin and high glucose both induced ferroptosis in mesangial cells. Suppression of HMGB1 restored cellular proliferation, prevented ROS and LDH generation, decreased ACSL4, PTGS2, and NOX1, and increased GPX4 levels in mesangial cells. Furthermore, nuclear factor E2-related factor 2 (Nrf2) was decreased in DN patients and high glucose-mediated translocation of HMGB1 in mesangial cells. Knockdown of HMGB1 suppressed high glucose-induced activation of TLR4/NF-κB axis and promoted Nrf2 expression as well as its downstream targets including HO-1, NQO-1, GCLC, and GCLM. Collectively, these findings suggest that HMGB1 regulates glucose-induced ferroptosis via Nrf2 pathway in mesangial cells.
Optimal design of the drive motor based on the road condition of the electric vehicle
Authors: Wu Zhigang , Li Weili , Liu Xiaoke
Published: February 2021

Due to the progressive prevalence of electric vehicles (EV) in the last few decades, more concerns have been focussed on the drive motor efficiency and its manufacturing cost. This article presents an optimisation design method for EV's motor based on road condition to achieve more practical optimisation design. First, the magnetic circuit model of motor is established which can calculate the efficiency map. The correctness of the circuit model can be verified by comparing the calculated map with the testing map. Second, the objective function can be established by considering the feature of New European Driving Cycle (NEDC) cycle road condition into motor conditions and the time proportions for different motor conditions as the weights. Then, the optimisation design for the motor can be carried out by setting constraints of optimisation including the loss limitation, volume, and other geometrical feasibility. Two objective functions with efficiency as the single objective and efficiency–weight as the dual objective are constructed, and the difference between the two objective functions corresponding to the optimisation scheme is analysed at the end. The optimisation method proposed in this article can be employed in the optimal design of the drive motor under any road condition. The designed scheme obtained from optimisation can achieve the best performance in target under whole road conditions, and by weighing the contradiction between material optimisation and thermal design.
A model‐based method for rotor speed estimation of synchronous generators using wide area measurement system
Authors: Hosseini Hossein , Afsharnia Saeed
Published: February 2021

In this paper a novel method is proposed to estimate the rotor speed of synchronous generators in steady state and dynamic conditions using phasor measurement unit's data. This method uses the synchronous generator model to find the relationship between generator rotor speed and frequencies at different buses of the power system. The principles of the proposed method are first presented through a simple network consisting a generator connected to a transmission line. Afterward the general formulation is developed. To demonstrate the effectiveness of our method, IEEE 9‐bus and IEEE 39‐bus power systems are used as the benchmark systems. Different tests are carried out under three conditions including, normal condition, presence of measurement errors and uncertainty of the power system parameters. As well, the estimation results are compared with the results of other estimation methods. The results show the high accuracy of the proposed method in different conditions.
Agent-based modeling of a rule-based community energy sharing concept
Authors: Heendeniya Charitha Buddhika
Published: February 2021

In an energy community, the prosumers’ interactions are critical to ensure efficient use of renewable resources. Local energy sharing concepts where a coordinating agent typically regulates the energy transactions between prosumers intend to achieve such a sharing economy. The coordinating agent, known as the market agent or energy sharing agent, acts according to a set of rules to match the prosumers’ renewable energy surpluses and deficits. This paper describes an agent-based modeling strategy and a case study to demonstrate the interactions in an energy sharing community where each agent individually and collectively attempts to maximize renewable energy self-consumption. The prosumers attempt to achieve their individual and collective objectives by following a two-step rule-based strategy. In the first step, a building-integrated battery storage operation strategy based on a schedule improves the prosumer-level self-consumption while providing grid-friendly behavior. The next step involves an energy sharing strategy and an operating strategy for community-scale battery storage that maximizes the collective selfconsumption. Throughout the transactions, prosumers have no visibility of other prosumers; therefore, the energy sharing coordinator has the sole responsibility of orchestrating the energy exchanges between prosumers. Finally, we discuss the significance and future research outlook for energy interaction modeling at a community scale.
Vorstellung einer prospektiv randomisierten Multicenterstudie zum Vergleich der Hiatusplastik mit Nähten vs. Nähte mit Pledgets vs. resorbierbares Netz bei großen Hiatushernien
Authors: Koch Oliver , von Rahden Burkhard H. A. , Wykypiel Heinz , Schoppmann Sebastian F. , Függer Reinhold , Rosanelli Georg , Emmanuel Klaus , Weitzendorfer Michael
Published: February 2021

Hintergrund Die Hernienrezidivrate nach Versorgung von großen Hiatushernien ist nach wie vor sehr hoch. Über die optimale Versorgung des Hiatus bei großen Hiatushernien zur Senkung der Rezidivrate wird kontrovers diskutiert. Ziel dieser Arbeit ist es, zu klären, ob Pledget-verstärkte Nähte oder ein resorbierbares Netz die Rezidivrate im Vergleich zur ausschließlichen Nahtversorgung senken können.

Material und Methoden Es wurde eine österreichweite, multizentrische, prospektive, randomisierte Studie geplant. Durch das Hauptprüfzentrum (Universitätsklinik für Allgemein-, Viszeral- und Thoraxchirurgie, Paracelsus Medizinische Privatuniversität Salzburg) wurde das Studienprotokoll erstellt. Eingeschlossen in die Studie werden Patienten, die geplant wegen einer großen symptomatischen Hiatushernie laparoskopisch oder roboterassistiert operiert werden. Eine große Hiatushernie wird definiert als > 5 cm in der Manometrie bzw. Gastroskopie oder mindestens ⅓ des Magens intrathorakal liegend. Der primäre Studienendpunkt ist definiert als die Hernienrezidivrate, objektiv beurteilt mittels Gastroskopie. Nach Einschluss in die Studie werden die Patienten 6 Monate, 1 Jahr, 3 Jahre und 5 Jahre nach der Operation mithilfe von standardisierten Fragebögen und einer Gastroskopie nachbeobachtet. Die Fallzahlberechnung zeigt eine erforderliche Patientenanzahl von 55 pro Gruppe. Die präoperative Randomisierung und das Data Management erfolgen softwaregestützt.

Ergebnisse Die Studie wird aktuell durch die federführende Ethikkommission hinsichtlich eines positiven Votums bewertet und ist seit Oktober 2020 auf ClinicalTrials.gov registriert. Die Clinical Trials Registration Number lautet NCT04591860. Zum aktuellen Zeitpunkt nehmen 5 Kliniken an der Studie teil. Hierbei werden in allen Zentren aktiv Probanden eingeschlossen. Die Dauer der Studie wurde bis Januar 2027 festgesetzt.

Schlussfolgerung Diese Studie ist die weltweit erste prospektive, randomisierte Studie, welche die Wertigkeit von Pledgets und resorbierbaren Netzen zur Senkung der Rezidivrate nach Versorgung von großen Hiatushernien untersucht. Die Ergebnisse werden dazu beitragen, die Frage nach der adäquaten Versorgung des Hiatus zu klären.
Study on Palladium(II)-Catalyzed Mono-1-alkenylation of 9H-Carbazoles
Authors: Wang Yongqiang , Zhao Jinzhong , Guo Dongdong , Li Bin , Gao Wenmei , Zhang Wuxia
Published: February 2021

A general and efficient method is reported for the direct mono-1-alkenylation of 9H-carbazole molecules with divalent palladium as a catalyst and an N-(2-pyridyl)sulfanyl directing group. This method also provides an efficient synthetic route for the synthesis of cross-dialkenylated carbazoles.
Pyrrolidine and Indolizidine Alkaloids from Chiral N-tert-Butanesulfinyl Imines Derived from 4-Halobutanal
Authors: Yus Miguel , Foubelo Francisco , Sirvent Ana , Hernández-Ibáñez Sandra
Published: February 2021

An efficient stereocontrolled preparation of 2-substituted pyrrolidines and 5-substituted indolizidin-7-ones, by using chiral N-tert-butanesulfinyl imines derived from 4-halobutanal as starting materials, is detailed. Addition of Grignard reagents and a decarboxylative Mannich­ reaction with β-keto acids involving these chiral imines proceeded with high diastereoselectivity. The synthesis of the pyrrolidinic alkaloids (–)-bgugaine, (+)-villatamine B, (–)-norhygrine, trans-dendrochrysanine, and (–)-ruspolinone demonstrated the utility of this methodology.
Clinical Characteristics and Remedy Profiles of Patients with COVID-19: A Retrospective Cohort Study
Authors: Jethani Bipin , Gupta Meeta , Wadhwani Parul , Thomas Rekha , Balakrishnan Thankaraj , Mathew George , Mathur Mohit , Rao Bachha Pompi , Shukla Dhananjay , Khullar Aashima , Khera Meghna , Sharma Himani , Kumar Ravinder , Kumar Sudeep , Jaggi Sayami , Sinha Robin , Rawal Kamal , Kapoor Anu , Manchanda Raj Kumar
Published: February 2021

Objective The aim of the study was to identify indicated homeopathic remedies based on the clinical characteristics of coronavirus disease 2019 (COVID-19) patients in India.

Methods In this retrospective, cohort study, confirmed COVID-19 patients admitted at a COVID Health Centre in New Delhi between April 29 and June 17, 2020 were given conventional and homeopathic treatment. Patients were grouped into mild, moderate or severe categories of disease. Their symptomatologic profiles were analyzed to identify indicated homeopathic medicines.

Results A total of 196 COVID-19 patients were admitted. One hundred and seventy-eight patients had mild symptoms; eighteen patients had moderate symptoms; no patients with severe symptoms were included as they were referred to tertiary care centers with ventilatory support. The mean age of patients with mild symptoms was significantly lower (38.6 years; standard deviation or SD ± 15.8) compared with patients in the moderate category (66.0 years; SD ± 9.09). The most important symptoms identified were fever (43.4%), cough (47.4%), sore throat (29.6%), headache (18.4%), myalgia (17.9%), fatigue (16.8%), chest discomfort (13.8%), chills (12.6%), shortness of breath (11.2%) and loss of taste (10.2%). Twenty-eight homeopathic medicines were prescribed, the most frequently indicated being Bryonia alba (33.3%), Arsenicum album (18.1%), Pulsatilla nigricans (13.8%), Nux vomica (8%), Rhus toxicodendron (7.2%) and Gelsemium sempervirens (5.8%), in 30C potency.

Conclusion Data from the current study reveal that Arsenicum album, Bryonia alba, Pulsatilla nigricans, Nux vomica, Rhus toxicodendron and Gelsemium sempervirens are the most frequently indicated homeopathic medicines. A randomized controlled clinical trial based on this finding is the next step.
Características eletrofisiológicas das pessoas diabéticas com síndrome do túnel do carpo
Authors: Paiva Filho Henver Ribeiro , Reis Alex Timóteo Rodrigues , Matos Gabriel Antonio , Paiva Valdênia Graças Nascimento , Oliveira Elias Felix , Rocha Murilo Antônio
Published: February 2021

Objetivo O presente trabalho teve por objetivo verificar se existe correlação entre a síndrome do túnel do carpo (STC) e eletroneuromiografia (ENMG) de pacientes diabéticos e não diabéticos.

Métodos Foram avaliados 154 pacientes em um ambulatório de cirurgia da mão. Todas as ENMGs avaliadas foram realizadas por um único neurologista, bilateralmente. As variáveis qualitativas foram descritas para todas as pessoas em acompanhamento devido à STC segundo a presença de diabetes e foi verificada a associação com uso do teste qui-quadrado. Foi ajustado o modelo conjunto para verificar a influência da diabetes na gravidade da ENMG em pacientes com STC.

Resultados Foram incluídos no presente estudo 117 mulheres e 37 homens, com média de idade de 56,9 anos. Eletroneuromiografia demonstrando STC bilateral foi observada em 82,5% das pessoas. Pessoas diabéticas foram identificadas em 21,4% dos casos. Eletroneuromiografia com padrão grave foi prevalente.

Conclusão Não houve associação entre a presença de diabetes e a gravidade da ENMG em pessoas com STC. Nível de evidência IV, série de casos.
Interventions for Distal Radius Fractures: A Meta-analysis of Comparison Studies
Authors: Beyer Julia , Wynkoop Emily , Liu Jiayong , Ebraheim Nabil A.
Published: February 2021

Background Distal radius fractures are one of the most frequent orthopaedic injuries. There are many effective treatment methods, such as volar plate, dorsal plate, percutaneous pins, external fixation, and casting; however, comparison of the treatment outcomes has not been thoroughly investigated. Our purpose is to determine if volar plating is the superior treatment method for distal radius fractures. We will address this through the following questions: First, is volar plating superior to dorsal plating, percutaneous pins, external fixation, or casting in terms of reported complications? Second, does volar plating produce superior functional outcomes to dorsal plating, percutaneous pins, external fixation, or casting? Third, are the radiographic outcomes superior for volar plating when compared with dorsal plating, percutaneous pins, external fixation, or casting?

Methods MEDLINE, Academic Search Ultimate, Academic Search Complete, CINAHL Plus, and JSTOR databases, as well as manual search, were used to identify papers comparing complications and functional results of volar plating to other treatment methods for distal radius fractures published after the year 2000. Complication data and function scores were recorded. Risk of bias was assessed using the Cochrane Risk of Bias Tool and data was analyzed for meta-analysis using Cochrane ReviewManager software.

Results Compared with dorsal plate, volar plate performed significantly better in Gartland and Werley score. Volar plating outperformed percutaneous pins for loss of reduction, infection, Disabilities of the Arm, Shoulder, and Hand (DASH) score, and ulnar deviation. Loss of reduction, malunion, Patient Related Wrist Evaluation (PRWE) score, DASH score, grip strength, ulnar deviation, and supination were significantly better for volar plating when compared with casting. When compared with external fixation, volar plating had significantly less cases of infection, lower QuickDASH score, and higher range of motion for flexion, pronation, and supination. All other complication and functional outcomes were not significantly different.

Conclusions Distal radius fractures treated with volar plating showed relatively better measures of complications, function scores, and range of motion than other treatment methods; however, there was no significant difference in healing time when compared with percutaneous pins. More studies are needed to compare the rest of the treatment methods with each other.
Quantum efficiency of photocatalytic activity by GaN films
Authors: Shimosako N. , Sakama H.
Published: February 2021

We have evaluated the quantum efficiency of photocatalytic activity by GaN films using methylene blue decomposition. The quantum efficiency of GaN was found to be comparable to that of TiO2, which is widely used as a general photocatalyst. These results suggest that GaN photocatalysts are effective to decompose not only water but also toxic compounds. Optimized GaN photocatalysts are expected to show even higher photocatalytic activity.
Resolution of the identity approximation applied to PNOF correlation calculations
Authors: Lew-Yee Juan Felipe Huan , Piris Mario , M. del Campo Jorge
Published: February 2021

In this work, the required algebra to employ the resolution of the identity approximation within the Piris Natural Orbital Functional (PNOF) is developed, leading to an implementation named DoNOF-RI. The arithmetic scaling is reduced from fifth-order to fourth-order, and the memory scaling is reduced from fourth-order to third-order, allowing significant computational time savings. After the DoNOF-RI calculation has fully converged, a restart with four-center electron repulsion integrals can be performed to remove the effect of the auxiliary basis set incompleteness, quickly converging to the exact result. The proposed approach has been tested on cycloalkanes and other molecules of general interest to study the numerical results, as well as the speed-ups achieved by PNOF7-RI when compared with PNOF7.
Sound insulation via a reconfigurable ventilation barrier with ultra-thin zigzag structures
Authors: Chen Di-Chao , Wei Qi , Yan Peng-Yi , Zhu Xing-Feng , Wu Da-Jian
Published: February 2021

Acoustic ventilation barriers (AVBs) constructed from metamaterials can effectively insulate sound waves while maintaining airflow, but previous schemes suffer from complex geometric structures. Here, we propose a reconfigurable AVB with subwavelength thickness (0.15λ), which is composed of simple zigzag structures with regular intervals and can be assembled into a full enclosure with an arbitrary shape. It is the interaction between the scattered wave of the zigzag structure and the un-scattered wave through the air channel that leads to a transmission dip and hence a sound insulation. Numerical simulations and experimental demonstrations consistently verify that the AVB possesses excellent omnidirectional sound insulation, while the width of the air channel can reach three times the unit width. As the number of cavity increases, the acoustic insulation bandwidth is broadened from 0.875/λ to 2.75/λ. As an example, a circle AVB is further demonstrated to shield acoustic waves emitting from either the interior or exterior. Experimental measurements indicate that the average sound transmission losses can reach roughly 19 dB and 15 dB, respectively. We believe that the proposed AVB may find potential applications in architectural acoustics, room acoustics, and duct noise control.
Optical solitons in birefringent fibers with quadratic-cubic nonlinearity using three integration architectures
Authors: Gómez-Aguilar J. F. , Osman M. S. , Raza Nauman , Zubair Asad , Arshed Saima , Ghoneim Mohamed E. , Mahmoud Emad E. , Abdel-Aty Abdel-Haleem
Published: February 2021

In this work, the nonlinear Schrödinger’s equation is studied for birefringent fibers incorporating four-wave mixing. The improved tanϕ(ξ)2-expansion, first integral, and G′G2-expansion methods are used to extract a novel class of optical solitons in the quadratic-cubic nonlinear medium. The extracted solutions are dark, periodic, singular, and dark-singular, along with other soliton solutions. These solutions are listed with their respective existence criteria. The recommended computational methods here are uncomplicated, outspoken, and consistent and minimize the computational work size, which give it a wide range of applicability. A detailed comparison with the results that already exist is also presented.
Photoelectric absorption cross section of silicon near the bandgap from room temperature to sub-Kelvin temperature
Authors: Stanford C. , Wilson M. J. , Cabrera B. , Diamond M. , Kurinsky N. A. , Moffatt R. A. , Ponce F. , von Krosigk B. , Young B. A.
Published: February 2021

The use of cryogenic silicon as a detector medium for dark matter searches is gaining popularity. Many of these searches are highly dependent on the value of the photoelectric absorption cross section of silicon at low temperatures, particularly near the silicon bandgap energy, where the searches are most sensitive to low mass dark matter candidates. While such cross section data have been lacking from the literature, previous dark matter search experiments have attempted to estimate this parameter by extrapolating it from higher temperature data. However, discrepancies in the high temperature data have led to order-of-magnitude differences in the extrapolations. In this paper, we resolve these discrepancies by using a novel technique to make a direct, low temperature measurement of the photoelectric absorption cross section of silicon at energies near the bandgap (1.2 eV–2.8 eV).
Cross-plane thermal conductivity of GaN/AlN superlattices
Authors: Spindlberger Anna , Kysylychyn Dmytro , Thumfart Lukas , Adhikari Rajdeep , Rastelli Armando , Bonanni Alberta
Published: February 2021

Heterostructures consisting of alternating GaN/AlN epitaxial layers represent the building blocks of state-of-the-art devices employed for active cooling and energy-saving lightning. Insights into the heat conduction of these structures are essential in the perspective of improving the heat management for prospective applications. Here, the cross-plane (perpendicular to the sample's surface) thermal conductivity of GaN/AlN superlattices as a function of the layers' thickness is established by employing the 3ω-method. Moreover, the role of interdiffusion at the interfaces in the phonon scattering is taken into account in the modeling and data treatment. It is found that the cross-plane thermal conductivity of the epitaxial heterostructures can be driven to values as low as 5.9 W/(m·K) comparable with those reported for amorphous films, thus opening wide perspectives for optimized heat management in III-nitride-based epitaxial multilayers.
Utilizing four-node tetrahedra-shaped Hopfield neural network configurations in the local magnetization assessment of 3d objects exhibiting hysteresis
Authors: Adly A. A. , Abd-El-Hafiz S. K.
Published: February 2021

There is no doubt that the accurate assessment of local magnetization in three-dimensional objects exhibiting hysteresis is crucial to accurate performance estimation of a variety of electromagnetic devices. Recently, it has been demonstrated that a Stoner-Wohlfarth-like elementary hysteresis operator may be constructed using two-node Hopfield neural network (HNN) having internal positive feedback. Based upon the previously mentioned approach, this paper presents a methodology using which local magnetization in 3D objects exhibiting hysteresis may be assessed. The approach utilizes a four-node tetrahedron-shaped HNN with activation functions constructed using a weighted superposition of a step and sigmoidal functions in accordance with the M − H curve of the material under consideration. In this approach, the internal feedback factors between the different nodes for any tetrahedron are dependent on its geometrical configuration. Hence, shape configuration effects on the magnetization patterns of any three-dimensional object approximated by an ensemble of tetrahedra are implicitly taken into consideration. To demonstrate the applicability of the proposed approach, computations were carried out for different three-dimensional magnetized bodies having different M − H curves. Theoretical and computational details of the approach are given in the paper.
Reduction of Nd moments and local magnetic anisotropy in Nd2Fe14B single crystals
Authors: Sato H. , Kubo Y. , Yoshioka T. , Tsuchiura H. , Mizuno Y. , Koike K. , Takahashi K. , Kato H.
Published: February 2021

Magnetization curves for Nd2Fe14B single crystals were measured between 300 K and 900 K. The saturation magnetization Ms along the [100] direction was found to be 2% to 4% smaller than that for the [001] direction, not only at 300 K but also up to the Curie temperature. We attributed this difference in Ms to the reduction of the Nd moment when forced to be aligned by external fields. Significant anisotropy was observed in the paramagnetic susceptibility χ up to 900 K. Based on the crystalline electric field parameters for Nd2Fe14B obtained by first-principles calculation, we calculated the magnetization and paramagnetic susceptibility χ. The difference in Ms and χ obtained from the calculation was in good agreement with the experiment. We found that the reduction rates for the Nd moments at 4f site are much smaller than that for the Nd moments at 4g site. This result therefore suggests a significant deterioration of local magnetic anisotropy at the Nd(4f) site even at elevated temperatures.
Magnetic anisotropy and electrical property of CoZrTaB thin films deposited by oblique sputtering
Authors: Tummalapalli Sridutt , Yu Hongbin
Published: February 2021

Soft magnetic materials have been studied extensively in recent years due to their applications in micro-transformers, micro-inductors, spin dependent memories etc. Achieving high uniaxial anisotropy is one of the most important properties for these materials. Oblique angle sputtering without the presence of the magnetic field enables the ease thus lower cost of the adoption of magnetic materials in applications. With a highly soft magnetic material, one can operate the devices made out of these films at giga hertz regions without significant loss of efficiency thus desirable for applications such as power conversion and radio frequency (RF) devices. This work focuses on analyzing different growth conditions of thin films of CoZrTaB and the resulting magnetic and electrical properties of the films. Thin films are grown by oblique-angle sputtering, where the sputtering gun forms an angle with respect to the sample substrate normal, ranging from 0 to 75 degrees. External magnetic field normally applied in order to form magnetic anisotropy is not used during film sputtering process. Using vibrating sample magnetometer, it was observed that films resulting from small oblique angles have no clear magnetic anisotropy developed; whereas in samples deposited at large angles close to 60°, there is clear magnetic anisotropy observed. Scanning electron microscopy imaging of the cross-section of film suggests the formation of tilted columns, which is likely to be the reason for magnetic anisotropy. Resistivity of the films was measured systematically and found to increase as the magnitude of oblique angle during sputtering increased.
The origin and early spread of SARS-CoV-2 in Europe
Authors: Nadeau Sarah A. , Vaughan Timothy G. , Scire Jérémie , Huisman Jana S. , Stadler Tanja
Published: February 2021

Significance

We estimate the origin and spread of SARS-CoV-2 in Europe prior to spring 2020 border closures based on viral genome sequences using a phylodynamic model with geographic structure. We confirm that the predominant European outbreak most likely started in Italy and spread from there. This outbreak was probably seeded by a transmission event in either Hubei, China or Germany. In particular, we find that before the first border closures in Europe, the rate of new cases occurring from within-country transmission was within or exceeded the estimated bounds on the rate of new migration cases.
Demographic perspectives on the rise of longevity
Authors: Vaupel James W. , Villavicencio Francisco , Bergeron-Boucher Marie-Pier
Published: February 2021

This article reviews some key strands of demographic research on past trends in human longevity and explores possible future trends in life expectancy at birth. Demographic data on age-specific mortality are used to estimate life expectancy, and validated data on exceptional life spans are used to study the maximum length of life. In the countries doing best each year, life expectancy started to increase around 1840 at a pace of almost 2.5 y per decade. This trend has continued until the present. Contrary to classical evolutionary theories of senescence and contrary to the predictions of many experts, the frontier of survival is advancing to higher ages. Furthermore, individual life spans are becoming more equal, reducing inequalities, with octogenarians and nonagenarians accounting for most deaths in countries with the highest life expectancy. If the current pace of progress in life expectancy continues, most children born this millennium will celebrate their 100th birthday. Considerable uncertainty, however, clouds forecasts: Life expectancy and maximum life span might increase very little if at all, or longevity might rise much faster than in the past. Substantial progress has been made over the past three decades in deepening understanding of how long humans have lived and how long they might live. The social, economic, health, cultural, and political consequences of further increases in longevity are so significant that the development of more powerful methods of forecasting is a priority.
Quantifying asymptomatic infection and transmission of COVID-19 in New York City using observed cases, serology, and testing capacity
Authors: Subramanian Rahul , He Qixin , Pascual Mercedes
Published: February 2021

Significance

As health officials face another wave of COVID-19, they require estimates of the proportion of infected cases that develop symptoms, and the extent to which symptomatic and asymptomatic cases contribute to community transmission. Recent asymptomatic testing guidelines are ambiguous. Using an epidemiological model that includes testing capacity, we show that many infections are nonsymptomatic but contribute substantially to community transmission in the aggregate. Their individual transmissibility remains uncertain. If they transmit as well as symptomatic infections, the epidemic may spread at faster rates than current models often assume. If they do not, then each symptomatic case generates, on average, a higher number of secondary infections than typically assumed. Regardless, controlling transmission requires community-wide interventions informed by extensive, well-documented asymptomatic testing.
L2 English learners’ knowledge of figurative meaning senses of phrasal verbs
Authors: Kang Dae-Min
Published: February 2021

While phrasal verbs (PVs) represent “a problematic feature of English vocabulary” (Garnier & Schmitt, 2016, p. 29) for a large number of learners, research into L2 English PVs remains
insufficient. This study examines 150 tertiary-level L2 English learners’ knowledge of figurative meaning senses of PVs and the
influence of congruence in the figurative meaning senses between L1 and L2 on their knowledge of the meaning senses. The research
instruments consisted of a form-recall and a meaning-recall task, questionnaires, and focus group interviews. The results indicate
that the learners’ PV knowledge differed significantly according to proficiency level and task type – production and reception.
Further, L1 congruence influenced the learners’ knowledge of PVs differently depending on proficiency levels.
The gravimagnetic dipole
Authors: Clément Gérard
Published: February 2021

We investigate a previously constructed stationary solution of the vacuum Einstein equations, which represents a system of two non-extreme black holes with equal masses and opposite NUT charges, connected by a Misner string with tension. For large separations, the inverse square law force measured by this tension is attractive or repulsive, according to the relative values of the masses and NUT charges. For small separations, the force is always repulsive, so that the system cannot collapse to a single black hole. For given values of the black hole masses and NUT charges, there is a unique configuration such that the Misner string is tensionless. This behaves asymptotically as the Kerr solution, but can be overspinning while remaining free from a ring singularity, thus evading the usual black hole uniqueness theorems. All double black hole and string configurations satisfy a generalized first law of black hole mechanics where the two black holes and the Misner string are treated on an equal footing.
All conformally flat Einstein–Gauss–Bonnet static metrics
Authors: Hansraj Sudan , Megandhren Govender , Banerjee Ayan , Mkhize Njabulo
Published: February 2021

It is known that the standard Schwarzschild interior metric is conformally flat and generates a constant density sphere in any spacetime dimension in Einstein and Einstein–Gauss–Bonnet (EGB) gravity. This motivates the questions: in EGB does the conformal flatness criterion yield the Schwarzschild metric? Does the assumption of constant density generate the Schwarzschild interior spacetime? The answer to both questions turn out in the negative in general. In the case of the constant density sphere, a generalised Schwarzschild metric emerges. When we invoke the conformal flatness condition the Schwarschild interior solution is obtained as one solution and another metric which does not yield a constant density hypersphere in EGB theory is found. For the latter solution one of the gravitational metrics is obtained explicitly while the other is determined up to quadratures in 5 and 6 dimensions. The physical properties of these new solutions are studied with the use of numerical methods and a parameter space is located for which both models display pleasing physical behaviour.
Inquiring the Unruh–DeWitt detector about the global property of spacetime
Authors: Sun Hongsong , Zhang Kaituo , Cai Huabing
Published: February 2021

We investigate the effect of spatial compactification on the transition rate of an inertial or accelerated Unruh–Dewitt detector coupled to an untwisted or twisted massless quantum scalar field. Four typical cases of the detector’s motion in the compactified Minkowski spacetime are considered respectively. Our results indicate that the detector’s transition rates are crucially dependent on the spatial compactification length, the magnitude and direction of detector’s velocity, the detector’s acceleration, and the field structure. As these factors change, the detector’s spontaneous emission and absorption processes can be enhanced or weakened at different degrees. In particular, when the compact length is small, the behavior of transition rate in the case of the twisted field is quite distinct from that of the untwisted field. Notably, when the detector moves at a constant velocity with nonzero components along the compact and non-compact directions, our study finds that the spontaneous emission rate depends on the component of velocity along the non-compact direction besides that along the compact direction. This is in sharp contrast with the case of the free Minkowski spacetime. Moreover, for the uniformly accelerated detector along the non-compact direction, the spatial compactification clearly modifies both the spontaneous emission and absorption rates, as the modifying factors depend on the compact length and the detector’s acceleration. Our work indirectly but comprehensively examines the nonequivalence of inertial frames in the compactified Minkowski spacetime, and meanwhile provides a theoretical way to identify the orientation and the size of the compact spatial dimension.
Solving an inverse heat convection problem with an implicit forward operator by using a projected quasi-Newton method
Authors: Rothermel Dimitri , Schuster Thomas
Published: February 2021

We consider the quasilinear 1D inverse heat convection problem of determining the enthalpy-dependent heat fluxes from noisy internal enthalpy measurements. This problem arises in the accelerated cooling process of producing thermomechanically controlled processed heavy plates made of steel. In order to adjust the complex microstructure of the underlying material, the Leidenfrost behavior of the hot surfaces with respect to the application of the cooling fluid has to be studied. Since the heat fluxes depend on the enthalpy and hence on the solution of the underlying initial boundary value problem (IBVP), the parameter-to-solution operator, and thus the forward operator of the inverse problem, can only be defined implicitly. To guarantee well-defined operators, we study two approaches for showing existence and uniqueness of solutions of the IBVP. One approach deals with the theory of pseudomonotone operators and so-called strong solutions in Sobolev–Bochner spaces. The other theory uses classical solutions in Hölder spaces. Whereas the first approach yields a solution under milder assumptions, it fails to show the uniqueness result in contrast to the second approach. Furthermore, we propose a convenient parametrization approach for the nonlinear heat fluxes in order to decouple the parameter-to-solution relation and use an iterative solver based on a projected quasi-Newton (PQN) method together with box-constraints to solve the inverse problem. For numerical experiments, we derive the necessary gradient information of the objective functional and use the discrepancy principle as a stopping rule. Numerical tests show that the PQN method outperforms the Landweber method with respect to computing time and approximation accuracy.
A particle-capturing and -separating, sheathless chip in series with microfilters and planar interdigital electrodes
Authors: Zhang Binzhen , Wang Yangyang , Liu Yunpeng , Li Huan , Zang Wenxuan , Duan Junping
Published: February 2021

Research on microfluidic chips is becoming more and more important in life sciences, medical testing, and chemical reactions. In the process of separating particles by dielectrophoresis (DEP), focusing of mixed particles is essential. The commonly used focusing method is sheath flow which dilutes the particle samples. However, it requires an additional injector which precludes development of an integrated system for chemical analysis and biological detection. In this paper, we propose a novel sheathless, shunt-focusing approach using microfilters (MFs) and interdigital electrodes to achieve particle capture and separation. By passing through a shrinking channel, most of the flowing small particles pass through the MFs, generating an artificial sheath flow in the channels to achieve focusing. Subsequently, interdigital electrodes provide DEP force to separate the particles. Separation efficiency was assessed by collecting polystyrene (20 μm diameter) from silica (4 μm diameter) at various flow rates. From the experimental results, the efficiency of capture reached 71%–86% and that of separation was over 98.6%. This chip is expected to be applied to the separation of circulating tumor cells in blood samples.