bluuebunny/crossref_metadata_2025 huggingface dataset:
A cardiovascular magnetic resonance imaging-based pilot study to assess coronary microvascular disease in COVID-19 patients
Authors: Drakos Stefanos , Chatzantonis Grigorios , Bietenbeck Michael , Evers Georg , Schulze Arik Bernard , Mohr Michael , Fonfara Helena , Meier Claudia , Yilmaz Ali
Published: August 2021

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and is primarily characterised by a respiratory disease. However, SARS-CoV-2 can directly infect vascular endothelium and subsequently cause vascular inflammation, atherosclerotic plaque instability and thereby result in both endothelial dysfunction and myocardial inflammation/infarction. Interestingly, up to 50% of patients suffer from persistent exercise dyspnoea and a post-viral fatigue syndrome (PVFS) after having overcome an acute COVID-19 infection. In the present study, we assessed the presence of coronary microvascular disease (CMD) by cardiovascular magnetic resonance (CMR) in post-COVID-19 patients still suffering from exercise dyspnoea and PVFS. N = 22 patients who recently recovered from COVID-19, N = 16 patients with classic hypertrophic cardiomyopathy (HCM) and N = 17 healthy control patients without relevant cardiac disease underwent dedicated vasodilator-stress CMR studies on a 1.5-T MR scanner. The CMR protocol comprised cine and late-gadolinium-enhancement (LGE) imaging as well as velocity-encoded (VENC) phase-contrast imaging of the coronary sinus flow (CSF) at rest and during pharmacological stress (maximal vasodilation induced by 400 µg IV regadenoson). Using CSF measurements at rest and during stress, global myocardial perfusion reserve (MPR) was calculated. There was no difference in left ventricular ejection-fraction (LV-EF) between COVID-19 patients and controls (60% [57–63%] vs. 63% [60–66%], p = NS). There were only N = 4 COVID-19 patients (18%) showing a non-ischemic pattern of LGE. VENC-based flow measurements showed that CSF at rest was higher in COVID-19 patients compared to controls (1.78 ml/min [1.19–2.23 ml/min] vs. 1.14 ml/min [0.91–1.32 ml/min], p = 0.048). In contrast, CSF during stress was lower in COVID-19 patients compared to controls (3.33 ml/min [2.76–4.20 ml/min] vs. 5.32 ml/min [3.66–5.52 ml/min], p = 0.05). A significantly reduced MPR was calculated in COVID-19 patients compared to healthy controls (2.73 [2.10–4.15–11] vs. 4.82 [3.70–6.68], p = 0.005). No significant differences regarding MPR were detected between COVID-19 patients and HCM patients. In post-COVID-19 patients with persistent exertional dyspnoea and PVFS, a significantly reduced MPR suggestive of CMD—similar to HCM patients—was observed in the present study. A reduction in MPR can be caused by preceding SARS-CoV-2-associated direct as well as secondary triggered mechanisms leading to diffuse CMD, and may explain ongoing symptoms of exercise dyspnoea and PVFS in some patients after COVID-19 infection.
Advances in chemical probing of protein O-GlcNAc glycosylation: structural role and molecular mechanisms
Authors: Saha Abhijit , Bello Davide , Fernández-Tejada Alberto
Published: August 2021

This review describes the recent developments in chemical probing of O-GlcNAcylation with a special focus on its molecular, structural and mechanistic implications.
Surface engineering of oncolytic adenovirus for a combination of immune checkpoint blockade and virotherapy
Authors: Lv Peng , Chen Xiaomei , Fu Shiying , Ren En , Liu Chao , Liu Xuan , Jiang Lai , Zeng Yun , Wang Xiaoyong , Liu Gang
Published: August 2021

A new strategy to coat oncolytic viruses in a bioengineered cell membrane with PD1 expression provides a clinical basis for combining oncolytic virotherapy with checkpoint inhibitors, resulting in a stronger antitumor immunity response.
Interconnected channels through polypropylene and cellulose acetate by utilizing lactic acid for stable separators
Authors: Kim So Hee , Kang Sang Wook
Published: August 2021

Lactic acid complexed with cellulose acetate. The interconnected structure of cellulose acetate in polypropylene chains. Connected water channels through cellulose acetate and polypropylene for enhanced separators.
Self-assembled nickel cubanes as oxygen evolution catalysts
Authors: García-Álvarez Ana C. , Gamboa-Ramírez Stefani , Martínez-Otero Diego , Orio Maylis , Castillo Ivan
Published: August 2021

Ni4O4 cubanes [(μ3-L1O)NiCl(MeOH)]4 (1) and [(μ3-L2O)NiCl(H2O)]4 (2) (L1OH = 1-H-2-benzimidazolylmethanol, L2OH = 1-methyl-2-benzimidazolylmethanol) self-assemble, providing easy access to oxygen evolution electrocatalysts.
Isomeric effects on the acidity of Al13 Keggin clusters in porous ionic crystals
Authors: Zhou Wei , Ogiwara Naoki , Weng Zhewei , Tamai Nanako , Zhao Congcong , Yan Li-Kai , Uchida Sayaka
Published: August 2021

Rotational isomers of polyoxoaluminum Al13 Keggin clusters exhibit remarkably different Brønsted acidities.
Modulation of supramolecular self-assembly of BODIPY tectons via halogen bonding
Authors: Özcan Emrah , Dedeoglu Burcu , Chumakov Yurii , Zorlu Yunus , Çoşut Bünyemin , Ayhan Mehmet Menaf
Published: August 2021

In this study, the efficiency of halogen bonding strategies to control over the supramolecular assemblies of boron dipyrromethene (BODIPY) (B-1, B-2, and B-3) derivatives was explored.
Adsorption of the amyloid β40 monomer on charged gold nanoparticles and slabs: a molecular dynamics study
Authors: Kalipillai Pandurangan , Mani Ethayaraja
Published: August 2021

Negatively charged nanoparticles inhibit the fibrillation of amyloid β (Aβ40).
Oscillatory dynamics during the methanol electrooxidation reaction on Pt(111)
Authors: da Silva Kaline Nascimento , Sitta Elton
Published: August 2021

The oscillatory methanol electrooxidation reaction on Pt(111) occurs at the Pt(111)–OH region and it is dependent on methanol and sulfate concentrations.
On the question of steric repulsionversusnoncovalent attractive interactions in chiral phosphoric acid catalyzed asymmetric reactions
Authors: Tribedi Soumi , Kitaura Kazuo , Nakajima Takahito , Sunoj Raghavan B.
Published: August 2021

The balance between attractive noncovalent interactions and the repulsive steric interaction is quantified in the enantiocontrolling transition states in chiral phosphoric acid catalyzed asymmetric transformations.
Correction: Eutectics: formation, properties, and applications
Authors: Yu Dongkun , Xue Zhimin , Mu Tiancheng
Published: August 2021

Correction for ‘Eutectics: formation, properties, and applications’ by Dongkun Yu et al., Chem. Soc. Rev., 2021, DOI: 10.1039/d1cs00404b.
Design and fabrication of integral carbon monoliths combining 3D printing and sol–gel polymerization: effects of the channel morphology on the CO-PROX reaction
Authors: Chaparro-Garnica Cristian Yesid , Bailón-García Esther , Lozano-Castelló Dolores , Bueno-López Agustín
Published: August 2021

A new method to synthesize integral carbon monoliths with a controlled channel morphology has been developed in this work by combining 3D-printing technology and sol–gel polymerization.
The impact of binary water–CO2 isotherm models on the optimal performance of sorbent-based direct air capture processes
Authors: Young John , García-Díez Enrique , Garcia Susana , van der Spek Mijndert
Published: August 2021

We outline mathematical descriptions of H2O–CO2 co-adsorption on an amine-functionalised solid sorbent and support this with experimental data. We then show what impact this has on a solid sorbent based direct air capture process.
Lactide-derived ester oligomers for highly compatible poly(lactide) plasticizer produced through an eco-friendly process: renewable resources, biodegradation, enhanced flexibility, and elastomeric performance
Authors: Jeong Haemin , Yuk Jeong Suk , Lee Hyunho , Kang Seomgyeol , Park Hyejin , Park Sae Hume , Shin Jihoon
Published: August 2021

Highly compatible PLA plasticizers were prepared using lactide, which demonstrated “double green” based on renewability and biodegradation, and “dual performances” including flexible and elastomeric behaviors.
Effective and viable photocatalytic degradation of rhodamine B dye in aqueous media using CuO/PVA nanocomposites
Authors: Mahar Zaheer Ahmed , Shar Ghulam Qadir , Balouch Aamna , Pato Abdul Hameed , Shaikh Abdul Rauf
Published: August 2021

Graphical representation of CuO/PVA nanocomposite synthesis to degrade rhodamine B dye in aqueous medium
Photochemistry of triphenylamine (TPA) in homogeneous solution and the role of transient N-phenyl-4a,4b-dihydrocarbazole. A steady-state and time-resolved investigation
Authors: Protti Stefano , Mella Mariella , Bonesi Sergio M.
Published: August 2021

Irradiation of triphenylamine with a laser pulse (355 nm) provided intermediate N-phenyl-4a,4b-tetrahydrocarbazole (DHC0) whose reactivity depends on the reaction media and atmospheres used.
Optimization of closed-cycle oil recovery: a non-thermal process for bitumen and extra heavy oil recovery
Authors: Sharma Pushpesh , Kostarelos Konstantinos , Salman Mohamad
Published: August 2021

The conceptual application of a single-phase microemulsion in the closed-cycle oil recovery approach for bitumen and extra-heavy oil reserves.
Modification of a nitrocellulose membrane with nanofibers for sensitivity enhancement in lateral flow test strips
Authors: Wang Xue , Xue Chao-Hua , Yang Dong , Jia Shun-Tian , Ding Ya-Ru , Lei Lei , Gao Ke-Yi , Jia Tong-Tong
Published: August 2021

We constructed a new type of ICT strip by replacing the conventional nitrocellulose membrane with an electrospin-coated nitrocellulose (ENC) fibrous membrane, and the ICT strip could obtain an HCG detection limit of 0.22 mIU mL−1, and an LH detection limit of 0.36 mIU mL−1.
Synergetic effect of C and Ni on hydrogen release from Mg–Ni-electrochemically synthesized reduced graphene oxide based hydride
Authors: Panda Srikanta , Satya Aditya Marla V. V. , Tatiparti Sankara Sarma V.
Published: August 2021

Schematic representation of synergetic effect aiding in superior hydrogen release from Mg–Ni–rGO nanocomposite.
Poly(NIPAM-co-thienoviologen) for multi-responsive smart windows and thermo-controlled photodynamic antimicrobial therapy
Authors: Zhang Yueyan , Zhou Kun , Jiang Huaiyu , Zhang Suikun , Zhang Bingjie , Guo Mengying , He Gang
Published: August 2021

Multi-responsive polymers based on thienoviologens and NIPAM were synthesized and applied in smart windows and thermo-controlled photodynamic antimicrobial therapy.
Unraveling the structural and morphological stability of oxygen vacancy engineered leaf-templated CaTiO3 towards photocatalytic H2 evolution and N2 fixation reactions
Authors: Kumar Ashish , Kumar Manish , Navakoteswara Rao Vempuluru , Shankar Muthukonda Venkatakrishnan , Bhattacharya Saswata , Krishnan Venkata
Published: August 2021

The leaf-templated and oxygen vacancy engineered CaTiO3 showed excellent structural stability but with loss in morphology for the studied binary phase photocatalytic reactions.
Nanosupercapacitors with fractal structures: searching designs to push the limit
Authors: Pei Liyuan , Zhuang Peiyuan , Sun Yangye , Zhang Xiang , Qiao Haohui , Zhu Keyu , Ajayan Pulickel M. , Ye Mingxin , Shen Jianfeng
Published: August 2021

Nanosupercapacitors with fractal structures are designed, fabricated by FIB and evaluated by modeling for enhanced microelectronic system powers.
All-in-one polarized Cd/CdS/halloysite ferroelectric hybrid for exceptional photocatalytic hydrogen evolution
Authors: Lin Sen , Li Shutao , Zhang Yihe , Ma Tianyi , Huang Hongwei
Published: August 2021

The substantially promoted charge separation, good dispersion and enhanced photo absorption allow Cd/CdS/halloysite an H2evolution rate of 32.11 mmol g−1h−1with an AQE of 45.13% at 420 nm, being one of the best CdS-based photocatalysts.
Nonlinear optical probes of nucleation and crystal growth: recent progress and future prospects
Authors: Dok Ahmet R. , Legat Thibaut , de Coene Yovan , van der Veen M. A. , Verbiest T. , Van Cleuvenbergen Stijn
Published: August 2021

Nonlinear optical techniques are emerging as powerfulin-situprobes of crystallization processes due to their inherent sensitivity to crystal structure and morphology.
A simple, repeatable and highly stable self-powered solar-blind photoelectrochemical-type photodetector using amorphous Ga2O3 films grown on 3D carbon fiber paper
Authors: Huang Lijuan , Hu Zhengrui , Zhang Hong , Xiong Yuanqiang , Fan Shiqiang , Kong Chunyang , Li Wanjun , Ye Lijuan , Li Honglin
Published: August 2021

A new type of self-powered solar-blind photoelectrochemical-type photodetector based on 3D a-Ga2O3/CFP core–shell structures was obtained. The device is simple, low cost, and has high reproducibility, and extreme stability.
Exploring chromatin structural roles of non-coding RNAs at imprinted domains
Authors: Llères David , Imaizumi Yui , Feil Robert
Published: August 2021

Different classes of non-coding RNA (ncRNA) influence the organization of chromatin. Imprinted gene domains constitute a paradigm for exploring functional long ncRNAs (lncRNAs). Almost all express an lncRNA in a parent-of-origin dependent manner. The mono-allelic expression of these lncRNAs represses close by and distant protein-coding genes, through diverse mechanisms. Some control genes on other chromosomes as well. Interestingly, several imprinted chromosomal domains show a developmentally regulated, chromatin-based mechanism of imprinting with apparent similarities to X-chromosome inactivation. At these domains, the mono-allelic lncRNAs show a relatively stable, focal accumulation in cis. This facilitates the recruitment of Polycomb repressive complexes, lysine methyltranferases and other nuclear proteins — in part through direct RNA–protein interactions. Recent chromosome conformation capture and microscopy studies indicate that the focal aggregation of lncRNA and interacting proteins could play an architectural role as well, and correlates with close positioning of target genes. Higher-order chromatin structure is strongly influenced by CTCF/cohesin complexes, whose allelic association patterns and actions may be influenced by lncRNAs as well. Here, we review the gene-repressive roles of imprinted non-coding RNAs, particularly of lncRNAs, and discuss emerging links with chromatin architecture.
Micro/mini-dystrophines et dystrophie musculaire de Duchenne : entre espoirs et défis
Authors: Lagrue Emmanuelle , Cancès Claude , Ropars Juliette
Published: August 2021

Les nombreux travaux précliniques de thérapie génique (TG) mis en œuvre afin de modifier l’histoire naturelle de la dystrophie musculaire de Duchenne (DMD), ont aujourd’hui abouti à la mise en place d’essais cliniques évaluant la sécurité et l’efficacité de l’administration de mini- ou micro-dystrophines chez l’enfant, et à terme peut-être chez l’adulte. Nous reprendrons dans cet article le principe général de la TG, les modèles animaux étudiés, les essais cliniques avec mini- ou micro-dystrophine actuellement en cours, et enfin les limites et effets indésirables possibles de ce type de thérapeutique innovante.
Features of consumer value management of an innovative product
Authors: Gaifutdinova Oksana , Poroshin Igor , Sergeeva Elena , Artemova Ekaterina
Published: July 2021

Today, much is being done in Russia to ensure that the country acquires the status of an innovation-oriented power that can occupy and maintain the world leading positions in the main, strategically important areas of the state's development. Successful development of any socio-economic entity operating in modern conditions is impossible without widespread usage of innovative technologies. New technologies are important in open innovation processes for enterprises, because due to them, they can meet customer expectations and achieve higher corporate financial performance. By creating new organizational connections to take advantage of emerging technological opportunities, entrepreneurs are restructuring the economy, driving change and overall economic growth. In addition to the focus on innovation, an important direction in the development concept of a socio-economic entity is solving environmental issues. More and more companies are thinking about creating environmentally friendly products with minimal impact on the environment. Such products have a higher attractiveness for the consumer and compete more successfully with foreign analogues. Creating an effective program of innovative growth in compliance with environmental requirements and standards is one of the most important factors in improving competitiveness and sustainable development of Russian enterprises.
The impact of leadership style on ethical decision-making, the moderating role of strategic thinking: a study among Malaysian managers
Authors: Balasubramaniam Vishalni , Salamzadeh Yashar , Richardson Christopher , Plakhin Andrey
Published: July 2021

This study develops and empirically tests a multilevel model of cross-level interactions between leadership style and ethical decision-making at the individual level. The study also examines the moderating role of strategic thinking support in the proposed cross-level relationships. Data were collected from 389 managers of electrical and electronic (E&E) companies in Penang. These data were evaluated using a partial least square-structural equation demonstrating via SmartPLS. Results confirmed the relationship between leadership style and ethical decision-making. Additionally, strategic thinking was found to perform the moderating role between leadership style and ethical decision-making. This research contributes to the literature on leadership styles and ethical decision-making. In recent times, no such study in (E&E) manufacturing context has been reported in Malaysia. Also using strategic thinking as a moderator is another novelty of this research.
Using machine learning methods in problems with large amounts of data
Authors: Kuimova Olga , Kukartsev Vladislav , Stupin Artem , Markevich Ekaterina , Apanasenko Stanislav
Published: July 2021

This article explores the use of artificial intelligence in medicine, in particular in radiology, pathology, drug development. The usefulness of robotic assistants in the medical field is revealed, including machine learning in medical science, as well as routing in hospitals. It also discusses such machine learning methods as classification methods, regression restoration methods, clustering methods. As a result, based on what is considered in this article, it is concluded that manual processing becomes more complicated and impossible with a large amount of data. There is a need for automatic processing that can transform modern medicine. And also, conclusions were made about how accurately the deep learning mechanisms can provide a more accurate result in the processing and classification of images compared to the results obtained at the human level. It became clear that deep learning not only aids in the selection and extraction of characteristics, but also has the potential to measure predictive target audiences and provide proactive predictions to help clinicians go a long way.
Tinnitus Management: The Utilization of a Hybrid Telehealth and In-Person Delivery Model
Authors: Scaglione Tricia , Kuzbyt Brianna
Published: August 2021

Telehealth, or the delivery of healthcare services from a distance, has historically been used to provide care to underserved populations and to those unable to visit a healthcare center. During the ongoing global COVID-19 pandemic, some providers of tinnitus healthcare services incorporated telehealth into their clinical protocols to allow for continued care for their patients while adhering to social distancing guidelines and safety measures. Bothersome tinnitus can negatively impact one's quality of life. Telehealth has been instrumental in treating this debilitating problem in a time when in-person care has not been easily available. The case of a patient with tinnitus is examined to demonstrate the use of a hybrid delivery model utilizing telehealth and in-person interactions to assess and manage her bothersome tinnitus. In-person services were used for audiological assessments and fitting of treatment devices, while telehealth was utilized for counseling, education, and remote programming of her treatment devices. This combined approach, which has allowed the patient to continue receiving care safely during the pandemic, can be continued for future care. Telehealth offers several advantages to patients and providers alike. While the COVID-19 pandemic will hopefully come to an end, telehealth services for tinnitus management may be here to stay.
Accuracy of ultrasonography in detecting radiolucent soft-tissue foreign bodies
Authors: Tahmasebi Morteza , Zareizadeh Hamdollah , Motamedfar Azim
Published: August 2021

Background and Objective: Detection of radiolucent soft-tissue foreign bodies is a challenging problem, which is especially further complicated when retained foreign body is highly suggested by clinicians but radiography is negative. So, blind exploration is sometimes hazardous for patients. The purpose of this study was to determine the accuracy of ultrasonography (USG) in detecting radiolucent soft-tissue foreign bodies in the extremities. Materials and Methods: From November 2011 to January 2012, patients with clinically suspected radiolucent soft-tissue foreign body and negative radiography were evaluated by USG with a 12-MHz linear array transducer. The patients with positive clinical and USG examination were included in our study and underwent exploration or USG removal. Results: Fifty-one patients underwent foreign body removal under ultrasonography-guided or surgical exploration and 47 patients had foreign body (31, 12, 3, and 1 case had thorn, wood, glass, and plastic, respectively). Ultrasound was positive in 50 patients. USG falsely predicted the presence of foreign body in four cases and was falsely negative in one of the cases. Accuracy, sensitivity, and positive predictive value were determined as 90.2%, 97.9%, and 92%, respectively. Conclusions: The real-time high-frequency USG is a highly sensitive and accurate tool for detecting and removing radiolucent foreign bodies which are difficult to be visualized by routine radiography.
The method of comparative-historical analysis: a tailor-made approach to public diplomacy research
Authors: Ohnesorge Hendrik W.
Published: August 2021

In view of the major methodological challenges which confront researchers in public diplomacy (PD), the paper recognizes the method of comparative-historical analysis (CHA) as an eminently suitable approach for robust empirical studies. The paper starts by exploring different conceptualizations and operationalizations of public diplomacy. Subsequently, four defining characteristics of CHA are identified: (1) CHA starts from a positivist epistemological perspective; (2) CHA-based research usually is concerned with “big questions;” (3) comparative methods are applied in CHA, either across different cases or within cases across time, allowing for in-depth analyses; (4) by considering respective starting points, specific historical developments, and cultural particulars, CHA is committed to methods drawn from historical research, including process tracing and causal narrative. The paper demonstrates that CHA, in view of these characteristics and with its highly interdisciplinary pedigree and methodological eclecticism, is eminently suited for studies exploring PD practices and outcomes. To provide a tailor-made approach for such endeavors, CHA is innovatively combined with the method of structured, focused comparison. Finally, drawing on both the different operationalizations of PD and the requirements of CHA, a comprehensive matrix for CHA-based PD research is presented, offering a tangible framework for future empirical analyses.
The impact of commuters’ psychological feelings due to delay on perceived quality of a rail transport
Authors: Rezapour Mahdi , Richard Ferraro F.
Published: August 2021

Public transport’s delay has become an integral part of the daily routine for many commuters, and become more intense as people are under more time pressure and deadline. This study was set forward to study a relationship between various psychological feelings that the commuters might experience due to delay and the level of transport satisfaction. One of the most notorious rail transport in Malaysia was employed as the case study. The passengers of that rail transport often experience more than an hour of delay due to malfunctions or other mechanical problems of that transport. Our instruments include 396 fully completed commuters’ responses at the locations of the waiting time. The instruments include three subsections: demographic, physical, and psychological behaviors that commuters might experience. An indicator was also used to obtain the passengers’ opinions about the impacts of delay on the level of the perceived quality of the transport. The ordered mixed logit model was employed for the analysis. The mixed model was considered to provide more flexibility and to prevent biased point estimates. That is especially important as it is expected that the point estimates of some commuters’ feelings might vary across population based on factors such as the commuters’ objectives of travel, or level of urgency to reach the destination. The results highlighted, for instance, the feelings of being tired or nervous to be random in predicting the perceived quality of the transport. The results also indicated that the interactions between age, gender, and level of education, and also neck pain, and an increased heartbeat should be considered, instead of their sole main effects. Also, evaluating the heterogeneity in taste revealed that the change in a random parameter of feeling nervous is dependent on the parameter of commuters’ gender. Overall, the results provide important insights regarding various feelings that the commuters experienced, which impact their perceived quality of rail transportation. Extensive discussion regarding the link between the study’s findings and mindsponse theory was given in the “Discussion” and “Conclusion” sections of this study.
Statistical analysis of non-Maxwellian electron distribution functions measured with angularly resolved Thomson scattering
Authors: Milder A. L. , Katz J. , Boni R. , Palastro J. P. , Sherlock M. , Rozmus W. , Froula D. H.
Published: August 2021

Angularly resolved Thomson scattering is a novel extension of Thomson scattering, enabling the measurement of the electron velocity distribution function over many orders of magnitude. Here, details of the theoretical basis of the technique and the instrument designed for this measurement are described. Angularly resolved Thomson-scattering data from several experiments are shown with descriptions of the corresponding distribution functions. A reduced model describing the distribution function is given and used to perform a Monte Carlo analysis of the uncertainty in the measurements. The electron density and temperature were determined to a precision of 12% and 21%, respectively, on average, while all other parameters defining the distribution function were generally determined to better than 20%. It was found that these uncertainties were primarily due to limited signal to noise and instrumental effects. Measurements with this level of precision were sufficient to distinguish between Maxwellian and non-Maxwellian distribution functions.
Atomistic insights into the structure of heptapeptide nanofibers
Authors: Peccati Francesca , Sodupe Mariona
Published: August 2021

Artificial amyloid-like nanofibers formed from short peptides are emerging as new supramolecular structures for catalysis and advanced materials. In this work, we analyze, by means of computational approaches, the preferred atomistic fibrillar architectures that result from the self-assembly of polar NY7, NF7, SY7, SF7, and GY7 peptides into steric zippers formed by two β-sheets (describing an individual steric zipper) and by four β-sheets. For all heptapeptides, except GY7, parallel β-sheet organizations with polar residues packed at the steric zipper appear to be the preferred assemblies for the two β-sheets system due to the formation of a strong network of hydrogen bonds. For GY7, however, an antiparallel organization with glycine at the steric zipper is the most stable one. The preferred architecture is mostly conserved when enlarging our model from two to four β-sheets. The present work shows that the relative stability of different architectures results from a delicate balance between peptide composition, side chain hydrophobicity, and non-covalent interactions at the interface and provides the basis for a rational design of new improved artificial prion-inspired materials.
First principles study of phase stability in Ba-based tantalate complex double perovskites
Authors: Gonzales Justin , Hu Jing , Muhich Christopher , Oswald Jay , Newman Nathan
Published: August 2021

Despite the practical importance of Ba-based perovskite dielectrics in microwave applications, the literature does not consistently agree which structural phases form. To provide insight, we use density functional methods to calculate Gibbs energies of structural polymorphs of 1:1 ordered Ba-based perovskites. Ba(In1/2Ta1/2)O3 has a ground state Fm3¯m cubic phase at 0 K, while Ba(Y1/2Ta1/2)O3, Ba(Gd1/2Ta1/2)O3, and Ba(Nd1/2Ta1/2)O3 form lower symmetry ground state phases. With increasing temperature, the structural phases change from monoclinic I2/m to trigonal R3¯ and finally to cubic Fm3¯m. For the zero and higher temperature conditions, the energy differences between the ground state and next higher energetic polymorphs are below 50 meV/atom and arise predominantly from changes in the octahedral tilts. The resulting coexistence of two or more polymorphs at room temperature and similar x-ray diffraction patterns may explain why so many papers report different phases for the same compound.
Hybrids of perovskite nanocrystals and SiO2 microfiber for robust and long-haul transmittable fiber lasers
Authors: Wang Weihua , Zhang Mingshui , Deng Fei , Wang Ziming , Wang Yue
Published: August 2021

Fiber lasers have broad prospects for the development of tunable high-performance photonic equipment and active fiber devices. However, they are still facing challenges, such as the limited emission wavelength and relatively high pump energy. Perovskite nanocrystals possess a large absorption cross-section, high quantum efficiency, long Auger lifetime, and tunable emission wavelength, which have been recognized as the promising gain media. In this work, a unique method was developed to form a type of fiber laser device based on high-quality SiO2 microfibers integrated with solution-processed perovskite nanocrystals. By this way, the robust and efficient fiber laser with characteristics of long-haul transmission, tunable laser mode, and high polarization state was effectively obtained. Our results represent a significant advancement in fiber lasers based on favorable perovskite nanocrystals and high-quality SiO2 microfiber and provide new possibilities for active fiber devices.
An 18.3-MJ charging and discharging pulsed power supply system for the Space Plasma Environment Research Facility (SPERF): The subsystem for the magnetosheath coils
Authors: Guan Jian , E Peng , Ma Xun , Mao Aohua , Deng Weijun , Ding Mingjun , Kang Chuanhui , Li Songjie , Xiao Jinshui , Tong Weiming , Li Hongtao
Published: August 2021

3D asymmetric magnetic reconnection is an important investigation of the Space Plasma Environment Research Facility, which is being built as a user facility at the Harbin Institute of Technology in China. Four magnetosheath coils, which consist of Poloidal Field (labeled PF) coils and Toroidal Field (labeled TF) coils, are used to generate the magnetic field and plasma environment for the reconnecting experiment. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite the magnetosheath coils to generate the required amplitude and duration of the magnetic field. The PPS system includes the PF PPS and TF PPS, which include four sets of PPSs, respectively. Each set of PF PPS and TF PPS consists of nine modules and four modules, respectively, and each module consists of a charge and discharge unit. The PF PPS can provide a pulsed current of no less than 360 kA for the corresponding PF coil at 0.11 ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 0.6 ms. The TF PPS can provide a pulsed current of no less than 200 kA for the corresponding TF coil at 0.08 ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 1.6 ms. The detailed design of the PPS has been discussed in this paper, and the detailed design of the main components in the discharge unit of the PPS is also given in this paper. Finally, the discharge tests of all the PPSs are carried out to verify the design of the PPSs, and the results of the PPSs in discharge tests indicate that all the PPSs meet the design requirements.
A statistical study of three-second foreshock ULF waves observed by the Magnetospheric Multiscale mission
Authors: Wang Shan , Chen Li-Jen , Ng Jonathan , Bessho Naoki , Le Guan , Fung Shing F. , Gershman Daniel J. , Giles Barbara L.
Published: August 2021

We perform a statistical study of 3-s ultra-low frequency (ULF) waves using Magnetospheric Multiscale observations in the Earth's foreshock region. The average phase velocity in the plasma rest frame is determined to be anti-sunward, and the intrinsic polarization is right-handed. We further examine the linear instability conditions based on the drift-bi-Maxwellian distribution functions according to the observed plasma conditions. The resulting instability is a solution to the common dispersion equation of the ion/ion right-hand non-resonant and left-hand resonant instabilities. The predicted wave propagation is also predominantly anti-sunward. The cyclotron resonant conditions of the solar wind and backstreaming beam ions are evaluated, and we find that, in some cases, the anti-sunward propagating waves can be resonant with beam ions, which was overlooked in previous studies. The study suggests that the dispersion equation provides the 3-s ULF waves a fundamental explanation that unifies a rich variety of resonant conditions.
Numerical study on cavitation over flat hydrofoils with arc obstacles
Authors: Lin Zhe , Tao Junyu , Yin Dapeng , Zhu Zuchao
Published: August 2021

Cavitation is a complex and unsteady phenomenon. When the cavity generated at the leading edge extends to the trailing edge, a cloud/supercavitation phenomenon appears. This type of cavitation moving downstream causes the flow to become more unstable. In this paper, the influence of different-sized arc obstacles on the cavitation evolution process is studied. The simulation accuracy is verified by comparing the numerical calculation results with the experimental results. The large edgy simulation results can effectively reproduce the unsteady evolution process of cavity formation, development, and shedding on flat hydrofoils with different structures. Results show that the obstacles of different structures affect the frequency of cavitation shedding and the distribution of air content on the flat hydrofoils. The arc obstacles on the flat hydrofoil can stabilize the cavity at the leading edge and reduce the size of the shedding cavity, thereby inhibiting the evolution of cavitation.
A simple method for energy calibration of keV incident electron beam using a contactless electrostatic voltmeter probe
Authors: Belhaj M. , Dadouch S.
Published: August 2021

A simple method is proposed to calibrate the energy of an electron beam. An electrical floating metal foil is irradiated by the incident electrons. The electron energy is deduced from the magnitude of the surface potential developed on the irradiated conductor surface. The measurement of the surface potential is made outside the vacuum chamber on a metallic slab connected through a coaxial feedthrough to the electron irradiated sample. The energy calibration obtained by this method is compared to the conventional method based on measuring the energy position of the backscattered electron elastic peak.
CAP/EA-ADC method for metastable anions: Computational aspects and application to π* resonances of norbornadiene and 1,4-cyclohexadiene
Authors: Dempwolff Adrian L. , Belogolova Alexandra M. , Sommerfeld Thomas , Trofimov Alexander B. , Dreuw Andreas
Published: August 2021

The second- and third-order algebraic-diagrammatic construction schemes for the electron propagator for studies of electron attachment processes [EA-ADC(2) and EA-ADC(3)] have been extended to include the complex absorbing potential (CAP) method for the treatment of electronic resonances. Theoretical and conceptual aspects of the new CAP/EA-ADC methodology are studied in detail at the example of the well-known 2Πg resonance of the nitrogen anion N2−. The methodology is further applied to π* shape resonances, for which ethylene is considered as a prototype. Furthermore, the first many-body treatment of the π+* and π−* resonances of norbornadiene and 1,4-cyclohexadiene is provided, which have served as model systems for the concept of through-space and through-bond interactions for a long time.
Effects of surface wettability on contact line motion in liquid–liquid displacement
Authors: Zheng Wenxiu , Wen Boyao , Sun Chengzhen , Bai Bofeng
Published: August 2021

The behaviors of oil–water–solid interfaces are of basic and applied importance for many fields, such as energy, geochemistry, and biomedical sciences, yet molecular mechanisms are still poorly known. In particular, the traditional adsorption–desorption mechanism based on a single compound does not work to describe the contact line for liquid–liquid–solid systems where the two liquids have similar interactions with the solid surface. Here, we present a series of experiments of water spreading in alkanes, i.e., n-decane, n-dodecane, and n-hexadecane, under various surface wettabilities. The contact line motion is captured by the high-speed camera, allowing us to analyze the friction coefficient, displacement distance and frequency, and activation free energy during the contact line motion via the molecular kinetic theory. We further develop a friction model of contact line motion in liquid–liquid–solid systems by establishing the activation free energy of liquid–liquid–solid systems as a function of the activation free energies of separate one-liquid systems. Results show that the contact line friction coefficients increase with the increasing hydrophobicity (e.g., for n-decane, the coefficient changes from 0.3072 to 2.1967 Pa·s), explained by the increase in the displacement distance and sharp decrease in the displacement frequency of the molecules. Additionally, we find a non-monotonic dependence of the contribution of the surface part to the activation free energy on the wettability, with a maximum percentage of 70%–80% at the intermediate wettability, where the reduced collisions of liquid molecules weaken the molecular adsorption/desorption process. Finally, we find that the correlation coefficient n in our model is affected by the surface wettability, with a maximum at the intermediate wettability, showing a good prediction of the results in the literature. The reason can be attributed to the non-monotonic effects of wettability on the surface part of the activation free energy in two-liquid systems.
Thermoelectric properties of the SnS monolayer: Fully ab initio and accelerated calculations
Authors: Gupta Raveena , Dongre Bonny , Carrete Jesús , Bera Chandan
Published: August 2021

An energetic and dynamical stability analysis of five candidate structures—hexagonal, buckled hexagonal, litharge, inverted litharge, and distorted-NaCl—of the SnS monolayer is performed using density functional theory. The most stable is found to be a highly distorted-NaCl-type structure. The thermoelectric properties of this monolayer are then calculated using the density functional theory and the Boltzmann transport equation. In terms of phonon scattering, there is a sharp contrast between this monolayer and bulk materials, where normal processes are more important. The calculations reveal that the SnS monolayer has enhanced electrical performance as compared to the bulk phase. As a consequence, high figures of merit ZT∼5 and ZT∼1.36 are predicted at 600 and 300 K, respectively, for the monolayer, ∼33 times higher than the ZT of its bulk analog. Therefore, this structure is an interesting candidate for room-temperature thermoelectric applications. A comparison between the fully ab initio results and simpler models based on relaxation times for electrons and phonons highlights the efficiency of computationally inexpensive models. However, ab initio calculations are found to be very important for the prediction of thermal transport properties.
Efficient treatment of molecular excitations in the liquid phase environment via stochastic many-body theory
Authors: Weng Guorong , Vlček Vojtěch
Published: August 2021

Accurate predictions of charge excitation energies of molecules in the disordered condensed phase are central to the chemical reactivity, stability, and optoelectronic properties of molecules and critically depend on the specific environment. Herein, we develop a stochastic GW method for calculating these charge excitation energies. The approach employs maximally localized electronic states to define the electronic subspace of a molecule and the rest of the system, both of which are randomly sampled. We test the method on three solute–solvent systems: phenol, thymine, and phenylalanine in water. The results are in excellent agreement with the previous high-level calculations and available experimental data. The stochastic calculations for supercells containing up to 1000 electrons representing the solvated systems are inexpensive and require ≤1000 central processing unit hrs. We find that the coupling with the environment accounts for ∼40% of the total correlation energy. The solvent-to-solute feedback mechanism incorporated in the molecular correlation term causes up to 0.6 eV destabilization of the quasiparticle energy. Simulated photo-emission spectra exhibit red shifts, state-degeneracy lifting, and lifetime shortening. Our method provides an efficient approach for an accurate study of excitations of large molecules in realistic condensed phase environments.
Static hysteresis modeling for grain-oriented electrical steels based on the phenomenological concepts of energy loss mechanism
Authors: Hamzehbahmani Hamed
Published: August 2021

This paper proposes an advanced approach to construct static hysteresis loop of Grain-Oriented (GO) electrical steels for dynamic modeling and energy loss analysis. The proposed approach is in line with the magnetic hysteresis and phenomenological concepts of rate-dependent and rate-independent energy loss components of ferromagnetic materials under time-varying magnetic fields. The proposed method can predominantly describe energy loss mechanism and magnetization processes of the material. Accuracy of this technique was validated on Epstein size laminations of 3% GO silicon steels. The results explicitly confirmed the effectiveness of the proposed method in dynamic hysteresis modeling of GO electrical steels at magnetizing frequencies up to 1 kHz and peak flux densities up to 1.7 T.
Direct numerical simulation of control of oblique breakdown in a supersonic boundary layer using a local cooling strip
Authors: Zhou Teng , Lu Yuhan , Liu Zaijie , Yan Chao
Published: August 2021

Control of oblique breakdown in a supersonic boundary layer at Mach 2.0 using a local cooling strip is investigated by direct numerical simulation. Previous studies have indicated that wall cooling can stabilize first-mode disturbances, but no study has yet investigated the use of local cooling to control oblique breakdown in a supersonic boundary layer. In the present work, local cooling strips with various temperatures and widths are utilized at different locations to control oblique breakdown. Insight is obtained into the stabilizing effect of a cooling wall on the evolution of various disturbances in the streamwise direction. A local cooling strip controls oblique breakdown mainly by suppressing the amplification of the fundamental oblique waves in the streamwise direction, and it is found that this suppressive effect is enhanced by increasing the width and decreasing the temperature of the strip. The stabilizing effect of a local cooling strip on higher-harmonic modes is reinforced when the strip is located farther downstream, although this effect is negligible when compared with the stabilizing effect on the fundamental oblique waves. When the cooling strip is placed in the midstream area, where the steady vortex mode is amplified to the order of the fundamental oblique waves, outstanding performance in suppressing transition is found. Furthermore, in addition to the stabilizing effect of the cooling wall on the fundamental oblique waves, the boundary layer is stabilized by rapid growth of higher-spanwise-wavenumber steady modes. Eventually, oblique breakdown is suppressed and substantial improvements in the skin-friction coefficient are also obtained.
Structural features of chalcogenide glass SiTe: An ovonic threshold switching material
Authors: Gu Rongchuan , Xu Meng , Yu Run , Qiao Chong , Wang Cai-Zhuang , Ho Kai-Ming , Wang Songyou , Miao Xiangshui , Xu Ming
Published: August 2021

The state-of-the-art phase-change memory is usually composed of ovonic threshold switching (OTS) material and ovonic memory switching (OMS) material for selective and data storage, respectively. OMS materials have been intensely studied, while the knowledge of the OTS mechanism is still inadequate. In this article, we have explored the local structure and electronic property of a simple OTS material, the amorphous (a-) SiTe, by first-principles calculations. The results reveal that most of the atoms in a-SiTe obey the “8-N” rule in contrast to a-GeTe, a well-studied OMS material. 76.5% of Si-centered configurations are in the form of randomly distributed tetrahedral clusters, while Te-centered configurations are relatively disordered without notable conformation. Furthermore, a large number of fivefold rings are found in a-SiTe. All of these structural characteristics lead to the high stability of a-SiTe, prohibiting its crystallization. In addition, the p state of Te also contributes much to the mid-gap states, which may be relevant for OTS behavior. Our findings provide an in-depth understanding of the structural signature and electronic properties of a-SiTe, having important implications for the design and applications of OTS materials.
Fracture and fatigue of thin crystalline SrTiO3 membranes
Authors: Harbola Varun , Xu Ruijuan , Crossley Samuel , Singh Prastuti , Hwang Harold Y.
Published: August 2021

The increasing availability of a variety of two-dimensional materials has generated enormous growth in the field of nanoengineering and nanomechanics. Recent developments in thin film synthesis have enabled the fabrication of freestanding functional oxide membranes that can be readily incorporated in nanomechanical devices. While many oxides are extremely brittle in bulk, recent studies have shown that, in thin membrane form, they can be much more robust to fracture as compared to their bulk counterparts. Here, we investigate the ultimate tensile strength of SrTiO3 membranes by probing freestanding SrTiO3 drumheads using an atomic force microscope. We demonstrate that SrTiO3 membranes can withstand an elastic deformation with an average strain of ∼6% in the sub-20 nm thickness regime, which is more than an order of magnitude beyond the bulk limit. We also show that these membranes are highly resilient upon a high cycle fatigue test, surviving up to a billion cycles of force modulation at 85% of their fracture strain, demonstrating their high potential for use in nanomechanical applications.