bluuebunny/crossref_metadata_2025 huggingface dataset:
Advancing the extended roles of 3D transition metal based heterostructures with copious active sites for electrocatalytic water splitting
Authors: Karthick Kannimuthu , Sam Sankar Selvasundarasekar , Kumaravel Sangeetha , Karmakar Arun , Madhu Ragunath , Bera Krishnendu , Kundu Subrata
Published: August 2021

This review highlights the importance of 3D transition metal based heterostructures with improved active sites for metal hydroxides, LDHs, oxides, sulfides and metal phosphides and the influencing roles of 3D foams in water splitting.
A novel yttrium-based metal–organic framework for the efficient solvent-free catalytic synthesis of cyanohydrin silyl ethers
Authors: Echenique-Errandonea Estitxu , Pérez Juana M. , Rojas Sara , Cepeda Javier , Seco José M. , Fernández Ignacio , Rodríguez-Diéguez Antonio
Published: August 2021

A novel MOF has been synthesized, characterized, and applied in the cyanosilylation of aldehydes and ketones being the first example of an yttrium MOF able to catalyze this reaction.
Enzymatic extraction of pectic oligosaccharides from finger citron (Citrus medica L. var. sarcodactylis Swingle) pomace with antioxidant potential
Authors: Yu Min , Xia Yuandan , Xie Wangling , Li Yunlong , Yu Xinjun , Zheng Jianyong , Zhang Yinjun
Published: August 2021

POS was obtained from finger citron pomace by enzymatic optimization extraction, with the highest yield of 64.5%. The purified FCPOS-1 possessed remarkable antioxidant properties, especially scavenging activity against DPPH radicals up to 94.07%.
Jellyfish skin polysaccharides enhance intestinal barrier function and modulate the gut microbiota in mice with DSS-induced colitis
Authors: Cao Yu , Gao Jingzhu , Zhang Lihua , Qin Ningbo , Zhu Beiwei , Xia Xiaodong
Published: August 2021

Jellyfish skin polysaccharides, isolated from Rhopilema esculentum Kishinouye, enhance intestinal barrier function and modulate the gut microbiota in mice with DSS-induced colitis.
Single-reactor tandem oxidation–amination process for the synthesis of furan diamines from 5-hydroxymethylfurfural
Authors: Sha Jin , Kusema Bright T. , Zhou Wen-Juan , Yan Zhen , Streiff Stephane , Pera-Titus Marc
Published: August 2021

A single-reactor tandem oxidation–amination process was engineered with bifunctional RuPd/C catalyst for the synthesis of secondary furan diamines.
Selective C(sp3)–H activation of simple alkanes: visible light-induced metal-free synthesis of phenanthridines with H2O2 as a sustainable oxidant
Authors: Zhang Yongqiang , Jin Yunhe , Wang Lifang , Zhang Qingqing , Meng Changgong , Duan Chunying
Published: August 2021

A visible light-induced metal-free C(sp3)–H phenanthridinylation of simple alkanes with isonitrile is developed with H2O2 as a terminal sustainable oxidant.
Development of an in-line magnetometer for flow chemistry and its demonstration for magnetic nanoparticle synthesis
Authors: Besenhard Maximilian O. , Jiang Dai , Pankhurst Quentin A. , Southern Paul , Damilos Spyridon , Storozhuk Liudmyla , Demosthenous Andreas , Thanh Nguyen T. K. , Dobson Peter , Gavriilidis Asterios
Published: August 2021

A highly sensitive magnetometer for flow chemistry to characterise magnetic nanoparticles in solution, in situ and in real-time is presented. This facilitates continuous quality control and high-throughput screening of magnetic nanoparticle syntheses.
Compartmentalized microfluidic chambers enable long-term maintenance and communication between human pluripotent stem cell-derived forebrain and midbrain neurons
Authors: Tong Ziqiu , Kwak Eunbi , Aguiar Alita , Peng Bo , Pouton Colin W. , Voelcker Nicolas H. , Haynes John M.
Published: August 2021

Open coculture microfluidic chambers embedding Matrigel for 3D culture of hPSCderived forebrain and midbrain neurons over 5 months with functional neural activity.
A photofabricated honeycomb micropillar array for loss-free trapping of microfluidic droplets and application to digital PCR
Authors: He Yu , Lu Zefan , Fan Hongliang , Zhang Tao
Published: August 2021

High-density and loss-free droplet trapping in a photofabricated honeycomb micropillar array for digital PCR.
An ultrahigh sensitivity micro-cliff graphene wearable pressure sensor made by instant flash light exposure
Authors: Zhang Yachu , Lin Han , Meng Fei , Liu Huai , Mesa David , Zhang Huihui , Huang Xiaodong , Lau Alan Kin Tak , Zhao Yuejin , Ma Tianyi , Jia Baohua
Published: August 2021

A graphene micro-cliff pressure sensor, fabricated using a single flashlight exposure, features ultrahigh sensitivity, fast response and low detection limit.
Microwave-accelerated and efficient synthesis of structurally diverse N-(2,2-diphenylvinyl)-β-oxoamides
Authors: Chen Xingpeng , Lei Yelong , Fu Duo , Xu Jiaxi
Published: August 2021

An efficient catalyst-free synthesis of N-(2,2-diphenylvinyl)-β-oxoamides was developed via electrophilic ring-opening of N-alkylaziridines with α-oxoketenes in situ generated from α-diazo-β-dicarbonyls under microwave irradiation.
Hetero-nanostructures constructed by 2D porous metal oxide/hydroxide nanosheets supported on 1D hollow Co9S8 nanowires for hybrid supercapacitors with high areal capacity
Authors: Pan Yifan , Wei Jinhe , Han Dandan , Xu Qian , Gao Dongyan , Yang Yaobin , Wei Yen
Published: August 2021

Porous-hollow Co9S8/NiCo-Mo one-dimensional (1D) hetero-nanostructures are synthesized on carbon cloth using a stepwise fabrication process as battery-type electrodes.
Assembly of iron oxide nanosheets at the air–water interface by leucine–histidine peptides
Authors: Hoinkis Nina , Lutz Helmut , Lu Hao , Golbek Thaddeus W. , Bregnhøj Mikkel , Jakob Gerhard , Bonn Mischa , Weidner Tobias
Published: August 2021

The fabrication of inorganic nanomaterials is important for a wide range of disciplines.
Enhanced 1.5 μm emission from Yb3+/Er3+ codoped tungsten tellurite glasses for broadband near-infrared optical fiber amplifiers and tunable fiber lasers
Authors: Yuan Jian , Zheng Guodong , Ye Yingyi , Chen Yongbin , Deng Tingting , Xiao Peng , Ye Yichen , Wang Weichao
Published: August 2021

Strong 1.5 μm emission with full width at half maximum of 64 nm is achieved in 3 mol% Yb2O3 and 1 mol% Er2O3 codoped tungsten tellurite glass. The present glass shows large gain bandwidth (6.78 × 10−26 cm3) and figure of merit (4.06 × 10−23 cm2 s).
Double diffusion for the programmable spatiotemporal patterning of multi-domain supramolecular gels
Authors: Cooke Hannah S. , Schlichter Lisa , Piras Carmen C. , Smith David K.
Published: August 2021

To achieve spatial resolution of a multi-component gel, a double diffusion approach is used which enables the precise programming of emergent self-assembled patterned domains with well-defined shapes and sizes.
Vacancy-induced high activity of MoS2 monolayers for CO electroreduction: a computational study
Authors: Jiao Dongxu , Tian Yu , Liu Yuejie , Cai Qinghai , Zhao Jingxiang
Published: August 2021

The introduction of suitable S-vacancies can endow the MoS2 monolayer with high electrocatalytic activity for CO reduction to CH4.
“Thiol–ene” click synthesis of chiral covalent organic frameworks for gas chromatography
Authors: Guo Jing-Xuan , Yang Cheng , Yan Xiu-Ping
Published: August 2021

A facile “thiol–ene” click strategy was reported to construct novel chiral COFs for gas chromatographic separation.
Exploiting asymmetric anthracene-based multifunctional materials based on a “bulky peripheral modification” strategy for constructing simplified efficient deep-blue fluorescent OLEDs
Authors: Guo Runda , Ye Shaofeng , Wang Yaxiong , Duan Yalei , Di Kaiyuan , Wang Lei
Published: August 2021

An asymmetric bulky periphery enveloping strategy is proposed to delicately manipulate molecules for the construction of novel multifunctional organic electronic materials.
A high-performance short-wave infrared phototransistor based on a 2D tellurium/MoS2 van der Waals heterojunction
Authors: Yao Jinrong , Chen Fangfang , Li Juanjuan , Du Junli , Wu Di , Tian Yongtao , Zhang Cheng , Yang Jinke , Li Xinjian , Lin Pei
Published: August 2021

A gate-tunable Te/MoS2 vdW heterostructure is fabricated, exhibiting favourable photodetection properties with a response spectrum covering the whole SWIR band.
Colloidally stable, magnetoresponsive liquid crystals based on clay nanosheets
Authors: Khoruzhenko Olena , Wagner Daniel R. , Mangelsen Sebastian , Dulle Martin , Förster Stephan , Rosenfeldt Sabine , Dudko Volodymyr , Ottermann Katharina , Papastavrou Georg , Bensch Wolfgang , Breu Josef
Published: August 2021

Sandwich of magnetic nanoparticles makes magneto-responsive liquid crystal.
Axial and helical thermally activated delayed fluorescence bicarbazole emitters: opposite modulation of circularly polarized luminescence through intramolecular charge-transfer dynamics
Authors: Sumsalee Patthira , Abella Laura , Roisnel Thierry , Lebrequier Sabrina , Pieters Grégory , Autschbach Jochen , Crassous Jeanne , Favereau Ludovic
Published: August 2021

The design of novel chiral donor–acceptor emitters based on C2-symmetric bicarbazoles is reported together with their photophysical and CPL properties, both displaying an interesting modulation as a function of the solvent polarity.
TFEB phosphorylation on Serine 211 is induced by autophagy in human synovial fibroblasts and by p62/SQSTM1 overexpression in HEK293 cells
Authors: Relic Biserka , Deroyer Celine , Malaise Olivier , Plener Zelda , Gillet Philippe , de Seny Dominique , Malaise Michel G.
Published: August 2021

Autophagy receptor p62/SQSTM1 signals a complex network that links autophagy-lysosomal system to proteasome. Phosphorylation of p62 on Serine 349 (P-Ser349 p62) is involved in a cell protective, antioxidant pathway. We have shown previously that P-Ser349 p62 occurs and is rapidly degraded during human synovial fibroblasts autophagy. In this work we observed that fingolimod (FTY720), used as a medication for multiple sclerosis, induced coordinated expression of p62, P-Ser349 p62 and inhibitory TFEB form, phosphorylated on Serine 211 (P-Ser211 TFEB), in human synovial fibroblasts. These effects were mimicked and potentiated by proteasome inhibitor MG132. In addition, FTY720 induced autophagic flux, LC3B-II up-regulation, Akt phosphorylation inhibition on Serine 473 but down-regulated TFEB, suggesting stalled autophagy. FTY720 decreased cytoplasmic fraction contained TFEB but induced TFEB in nuclear fraction. FTY720-induced P-Ser211 TFEB was mainly found in membrane fraction. Autophagy and VPS34 kinase inhibitor, autophinib, further increased FTY720-induced P-Ser349 p62 but inhibited concomitant expression of P-Ser211 TFEB. These results suggested that P-Ser211 TFEB expression depends on autophagy. Overexpression of GFP tagged TFEB in HEK293 cells showed concomitant expression of its phosphorylated form on Serine 211, that was down-regulated by autophinib. These results suggested that autophagy might be autoregulated through P-Ser211 TFEB as a negative feedback loop. Of interest, overexpression of p62, p62 phosphorylation mimetic (S349E) mutant and phosphorylation deficient mutant (S349A) in HEK293 cells markedly induced P-Ser211 TFEB. These results showed that p62 is involved in regulation of TFEB phosphorylation on Serine 211 but that this involvement does not depend on p62 phosphorylation on Serine 349.
Decoding the consecutive lysosomal degradation of 3-O-sulfate containing heparan sulfate by Arylsulfatase G (ARSG)
Authors: Kowalewski Björn , Lange Heike , Galle Sabrina , Dierks Thomas , Lübke Torben , Damme Markus
Published: August 2021

The lysosomal degradation of heparan sulfate is mediated by the concerted action of nine different enzymes. Within this degradation pathway, Arylsulfatase G (ARSG) is critical for removing 3-O-sulfate from glucosamine, and mutations in ARSG are causative for Usher syndrome type IV. We developed a specific ARSG enzyme assay using sulfated monosaccharide substrates, which reflect derivatives of its natural substrates. These sulfated compounds were incubated with ARSG, and resulting products were analyzed by reversed-phase HPLC after chemical addition of the fluorescent dyes 2-aminoacridone or 2-aminobenzoic acid, respectively. We applied the assay to further characterize ARSG regarding its hydrolytic specificity against 3-O-sulfated monosaccharides containing additional sulfate-groups and N-acetylation. The application of recombinant ARSG and cells overexpressing ARSG as well as isolated lysosomes from wild-type and Arsg knockout mice validated the utility of our assay. We further exploited the assay to determine the sequential action of the different sulfatases involved in the lysosomal catabolism of 3-O-sulfated glucosamine residues of heparan sulfate. Our results confirm and extend the characterization of the substrate specificity of ARSG and help to determine the sequential order of the lysosomal catabolic breakdown of (3-O-)sulfated heparan sulfate.
Network-based approach to identify prognosis-related genes in tamoxifen-treated patients with estrogen receptor-positive breast cancer
Authors: Wang Yanyan , Gong Xiaonan , Zhang Yujie
Published: August 2021

Tamoxifen is an estrogen receptor (ER) antagonist that is most commonly used for the treatment of ER-positive breast cancer. However, tamoxifen resistance remains a major cause of cancer recurrence and progression. Here, we aimed to identify hub genes implicated in the progression and prognosis of ER-positive breast cancer following tamoxifen treatment. Microarray data (GSE9893) for 155 tamoxifen-treated primary ER-positive breast cancer samples were obtained from the Gene Expression Omnibus database. In total, 1706 differentially expressed genes (DEGs), including 859 up-regulated and 847 down-regulated genes, were identified between relapse and relapse-free samples. Weighted correlation network analysis clustered genes into 13 modules, among which the tan and blue modules were the most significantly related to prognosis. From these two modules, we further identified and validated two prognosis-related hub genes (G-rich RNA sequence binding factor 1 (GRSF1) and microtubule-associated protein τ (MAPT)) via survival analysis based on several publicly available datasets. High expression of GRSF1 predicted poor prognosis, whereas MAPT indicated favorable outcomes in ER-positive breast cancer. Using breast cancer cell lines and tissue samples, we confirmed that GRSF1 was significantly up-regulated and MAPT was down-regulated in the tamoxifen-resistant group compared with the tamoxifen-sensitive group. The prognostic value of GRSF1 and MAPT was also verified in 48 tamoxifen-treated ER-positive breast cancer patients in our hospital. Gene set enrichment analysis (GSEA) suggested that GRSF1 was potentially involved in RNA degradation and cell cycle pathways, while MAPT was strongly linked to immune-related signaling pathways. Taken together, our findings established novel prognostic biomarkers to predict tamoxifen sensitivity, which may facilitate individualized management of breast cancer.
Adaptive event‐triggered control of multi‐agent systems with state constraints and unknown disturbances
Authors: Zhang Xi‐Zi , Lan Jie , Liu Yan‐Jun , Liu Lei
Published: August 2021

The leader‐following consensus problem of a class of non‐strict feedback multi‐agent systems with unknown disturbances, this paper develops a novel adaptive event‐triggered control strategy ground on the consideration of the full state constraints. Combining the dynamic surface control and event triggering mechanism, the unknown external disturbances are estimated by designing a disturbance observer. In order to deal with unknown functions, this paper employs the neural networks. On purpose of keeping the output variable within a constraint boundary, the barrier Lyapunov function is chosen during the design course. Then, through the backstepping method and the Lyapunov stability theorem, it is proved that all signals in the closed‐loop systems are bounded, and the control performance of the closed‐loop system is ensured by selecting design parameters reasonably. Eventually, the availability of the control strategy is guaranteed through experimental example.
Exploring longitudinal driving behaviour on a freeway deceleration lane using field operational test data
Authors: Lyu Nengchao , Wang Yugang , Wu Chaozhong , Wu Haoran , Wen Jiaqiang
Published: August 2021

The deceleration lane isbefore numbers to minus signs. a critical part of the freeway, enabling vehicles to exit the expressway safely and in an orderly fashion. However, drivers are human and thus make subjective decisions while driving; as such, each driver may approach and traverse the deceleration lane differently. This variance, which can cause major traffic disruptions and collisions, can be observed – and even mitigated, as proposed herein – based on a driver's particular characteristics. To study the variances in the longitudinal vehicle positions and microscopic operating characteristics of different drivers on a freeway exit area, a field operational test involving 46 subjects was carried out to collect data on driver characteristics, vehicle motion postures, micro‐driving operations, and road geometric elements. The 46 participants were observed based on experience and gender, and the mathematical statistical method was used to analyse driving differences in the deceleration lane. The results show that (1) the vehicle motion state can be divided into four operational stages on the deceleration lane: the pre‐deceleration process, the dynamic adjustment process, the first braking process, and the second braking process; (2) drivers generally adopted deceleration behaviour rather than maintain uniform speed when driving in the taper; (3) about 50% of drivers braked after entering the deceleration lane; (4) male drivers and skilled drivers were more inclined to drive at a higher speed on the deceleration lane, and female drivers showed a sharp increase in braking frequency once they travelled 110–150 m downstream of the taper starting point. The results of this study provide data and insights for deceleration lane design, traffic management, and driver training.
New analysis on two‐variable converter impedance model in grid‐connected systems
Authors: Shi Ying , Sun Yue , Liu Junliang , Du Xiong , Tai Heng‐Ming
Published: August 2021

This paper presents an in‐depth analysis for the two‐variable impedance model of a grid‐connected system. The two‐variable model describes the impedance using the frequency as well as the operating point variable. The impedance‐based stability analysis method cannot be directly applied because the conventional models are derived for a specific steady‐state operating point and the operating point varies during operation. Thus, this paper develops a new analysis method to shed light on the role the two‐variable model plays instability analysis. The proposed method not only analyzes the system stability at different operating points, but also enables the controller design to ensure system stability. Experimental results are presented to demonstrate the effectiveness of the proposed method.
La pince optique : Un outil interdisciplinaire
Authors: Westbrook Nathalie , Westbrook Christoph I.
Published: August 2021

L’invention de la pince optique, c’est l’histoire d’un chercheur qui s’amuse mais qui avance méthodiquement et patiemment pour améliorer un concept simple jusqu’à en faire un outil indispensable dans deux domaines de recherche très différents. En biologie et en physique atomique, la pince optique est devenue un instrument de laboratoire courant.
Editorial
Authors: Reimer Jens
Published: August 2021

Liebe Leserin, lieber Leser,

ich weiß nicht, ob Sie ‚White Lines‘ - eine in der Hauptsache
auf Ibiza spielende Netflix Serie aus dem Frühjahr 2020 - gesehen haben. Die
Süddeutsche Zeitung schrieb „eine Krimi-, Familien- und
Hedonismusgeschichte mit skurrilen Elementen, elektronischer Musik und
spektakulär inszenierten Partys“. Die Serie, die ich vor gut einem
Jahr vergnügt verfolgt habe, fiel mir beim Lesen des Beitrags der Autoren
Köhler und Grau, Köln, zum Thema ‚Kokain abseits von
pathologischem Konsum‘ ein.
Low Flow Venoarterial ECMO Support Management in Postcardiac Surgery Patient
Authors: Airan Ritu , Sharan Sandeep , Kapoor Poonam Malhotra , Chowdhury Ujjwal , Devagourou V. , John Archip
Published: August 2021

Venoarterial extracorporeal membrane oxygenation (VA ECMO) aims to fully support heart and lung function in postcardiac patients, ensuring end-organ perfusion and allowing time for possible heart recovery. VA ECMO is considered the modified and extended form of cardiopulmonary bypass (CPB), which is used to provide adequate tissue oxygenation. ECMO and the associated management protocols will mechanically support the patient and allow for the optimization of all aspects of care for the period of time necessary for the recovery of native cardiac or respiratory function. Significant technical advancements have been made in the equipment and the clinical management available for short- and long-term ECMO application. There are various parameters that have to be considered to evaluate whether the level of perfusion in patients on VA ECMO is adequate, and the outcomes of patients depend on them.
An ultralow-noise superconducting radio-frequency ion trap for frequency metrology with highly charged ions
Authors: Stark J. , Warnecke C. , Bogen S. , Chen S. , Dijck E. A. , Kühn S. , Rosner M. K. , Graf A. , Nauta J. , Oelmann J.-H. , Schmöger L. , Schwarz M. , Liebert D. , Spieß L. J. , King S. A. , Leopold T. , Micke P. , Schmidt P. O. , Pfeifer T. , Crespo López-Urrutia J. R.
Published: August 2021

We present a novel ultrastable superconducting radio-frequency (RF) ion trap realized as a combination of an RF cavity and a linear Paul trap. Its RF quadrupole mode at 34.52 MHz reaches a quality factor of Q ≈ 2.3 × 105 at a temperature of 4.1 K and is used to radially confine ions in an ultralow-noise pseudopotential. This concept is expected to strongly suppress motional heating rates and related frequency shifts that limit the ultimate accuracy achieved in advanced ion traps for frequency metrology. Running with its low-vibration cryogenic cooling system, electron-beam ion trap, and deceleration beamline supplying highly charged ions (HCIs), the superconducting trap offers ideal conditions for optical frequency metrology with ionic species. We report its proof-of-principle operation as a quadrupole-mass filter with HCIs and trapping of Doppler-cooled 9Be+ Coulomb crystals.
High-mobility ZnVxOy/ZnO conduction path in ZnO/V/ZnO multilayer structure
Authors: Li B. J. , Wei Y. S. , Liao C. H. , Chen W. H. , Chou C. Y. , Cheng C. , Liu C. Y.
Published: August 2021

In this study, a 300 °C-annealed 3 × 4 V/ZnO multilayer structure demonstrates the lowest resistivity (3.82 × 10−3 Ω cm) and the highest mobility (18 cm2/V s) among the studied V/ZnO multilayer structures. By measuring the energy bandgap (Eg), work function (Φ), and electron affinity (χ) by ultraviolet photoelectron spectroscopy and photoluminescence analysis, the corresponding energy band diagram at the ZnVxOy/ZnO interface can be constructed. A potential is observed at the ZnVxOy/ZnO interface, which induces the two-dimensional electron gas (2DEG) effect, and this is attributed to the high-mobility conduction path. The potential well directly relates to the Φ difference between the ZnO and ZnVxOy layers, which is determined to be 0.22, 0.46, and −0.1 eV for the as-deposited, 300 °C-annealed, and 500 °C-annealed V/ZnO multilayer structures, respectively. The 300 °C-annealed V/ZnO multilayer structure could possibly have the largest depth in the potential well. This supports the 2DEG mechanism for the high mobility of the 300 °C-annealed V/ZnO multilayer structure.
Implementation of skyrmion cellular automaton using Brownian motion and magnetic dipole interaction
Authors: Ishikawa Ryo , Goto Minori , Nomura Hikaru , Suzuki Yoshishige
Published: August 2021

In this study, we investigated the interaction between skyrmions in Brownian motion at room-temperature. Cells containing two skyrmions were implemented by controlling the magnetic anisotropy in the Ta/CoFeB/Ta/MgO/SiO2 structure. The interaction between skyrmions was investigated by fabricating a circuit with two cells in close proximity to each other. It was found that the minimum value of the correlation coefficient was −0.234. These results show that the Brownian motion of skyrmions can potentially realize unconventional computing such as stochastic calculations and ultra-low power computing.
Single-cycle all-fiber frequency comb
Authors: Xing Sida , Lesko Daniel M. B. , Umeki Takeshi , Lind Alexander J. , Hoghooghi Nazanin , Wu Tsung-Han , Diddams Scott A.
Published: August 2021

Single-cycle pulses with a deterministic carrier-envelope phase enable the study and control of light–matter interactions at the sub-cycle timescale, as well as the efficient generation of low-noise multi-octave frequency combs. However, current single-cycle light sources are difficult to implement and operate, hindering their application and accessibility in a wider range of research. In this paper, we present a single-cycle 100 MHz frequency comb in a compact, turnkey, and reliable all-silica-fiber format. This is achieved by amplifying 2 µm seed pulses in heavily doped Tm:fiber, followed by cascaded self-compression to yield 6.8 fs pulses with 215 kW peak power and 374 mW average power. The corresponding spectrum covers more than two octaves, from below 700 up to 3500 nm. Driven by this single-cycle pump, supercontinuum with 180 mW of integrated power and a smooth spectral amplitude between 2100 and 2700 nm is generated directly in silica fibers. To broaden applications, few-cycle pulses extending from 6 µm to beyond 22 µm with a long-term stable carrier-envelope phase are created using the intra-pulse difference frequency, and electro-optic sampling yields comb-tooth-resolved spectra. Our work demonstrates the first all-fiber configuration that generates single-cycle pulses and provides a practical source to study nonlinear optics on the same timescale.
Topological spin textures in a two-dimensional MnBi2(Se, Te)4 Janus material
Authors: Jiang Jiawei , Liu Xiang , Li Rui , Mi Wenbo
Published: August 2021

Realizing and controlling topological spin textures are widely attractive for their promising applications in information and communication technology. Here, using first-principles calculations and micromagnetic simulations, a stable magnetic Janus material MnBi2(Se, Te)4 with an inherent Dzyaloshinskii–Moriya interaction is proposed to stabilize a variety of topological magnetic structures under temperature and magnetic fields. Furthermore, a sub-10 nm skyrmion can spontaneously form in the absence of magnetic fields in MnBi2(Se, Te)4 by using van der Waals heterostructure engineering. These results provide a promising route for the generation and modulation of topological spin textures in two-dimensional spintronic devices.
Faraday isolator based on NTF crystal in critical orientation
Authors: Mironov E. A. , Palashov O. V. , Naumov A. K. , Aglyamov R. D. , Semashko V. V.
Published: August 2021

The characteristics of a magneto-optical material promising for the development of Faraday isolators for high-power lasers—the Na0.37Tb0.63F2.26 (NTF) solid solution crystal with a negative value of optical anisotropy parameter—were investigated. The value of the optical anisotropy parameter ξNTF = −0.26 ± 0.02 was refined in model experiments on samples with increased absorption, and the value of the thermo-optical constant Q characterizing thermally induced depolarization was measured to be QNTF = (3.44 ± 0.4)·10−6 K−1. The negative value of ξ indicates that the depolarization resulting from stress-induced birefringence in this material is strongly dependent on orientation and ensures the presence of a critical orientation [C], with the use of which the magnitude of thermally induced depolarization in the Faraday isolator may be significantly reduced. The [C] orientation is determined by the parameter ξ; therefore, its accurate measurement is of particular importance. The investigation of Faraday isolators based on NTF crystals cut in [001] and [C] orientations demonstrated a significant advantage of the critical orientation. According to the measurement result, with the use of crystals with normal absorption, it is possible to develop a traditional (single element) Faraday isolator operating at room temperature and ensuring the isolation ratio of about 30 dB at the laser radiation power of ∼7 kW. This makes the NTF crystal one of the most prospective magneto-active media.
Improved internal model control method for carbon content of argon–oxygen refining ferrochromium alloys
Authors: You Yuan , Wang Zhanli , Wei Bingkun , Jiang Baoliang
Published: August 2021

We propose an improved internal model control method for the carbon content in the production process of argon–oxygen refining ferrochromium alloys. In the actual process, the control output is restricted and cannot fully demonstrate the control effect. Therefore, by decomposing the traditional internal model controller, we achieved saturation compensation, overcoming this limitation. In addition, by referring to the current production process, the smelting stages with different carbon-content ranges were determined. Combined with the actual equipment conditions, an anti-saturation internal model controller structure and a controller saturation numerical expert system were constructed, forming a fully improved internal model control system. The proposed method fully utilizes the steady-state error-free characteristic of the internal model control, achieving the preset control goal and significantly shortening the smelting time and improving the smelting efficiency.
Experiments on thermal drift
Authors: Inasawa A. , Hara K. , Floryan J. M.
Published: August 2021

Thermal drift is a horizontal flow driven by a pattern interaction effect occurring on a solid surface; that is, the flow is driven by an interaction between surface topography and the heating pattern applied to the surface. The interaction generates surface forces through projection of the convective pressure field onto the surface topography—these forces drive the flow. The existence of thermal drift is demonstrated experimentally. Its basic characteristics, that is, variations of the strength and direction of the resulting flow as a function of the relative position of both patterns, were determined experimentally and theoretically. An excellent agreement between both sets of data has been demonstrated.
Numerical investigation of respiratory drops dynamics released during vocalization
Authors: Peña-Monferrer C. , Antao S. , Manson-Sawko R.
Published: August 2021

Release of drops from a human body has been the focus of many recent investigations because of the current COVID-19 pandemic. Indirect virus transmission from asymptomatic individuals has been proved to be one of the major infectious routes and difficult to quantify, detect, and mitigate. We show in this work a detailed and novel numerical investigation of drops released during vocalization from a thermal manikin using a large eddy simulation coupled with Lagrangian tracking of drops. The vocalization experiment was modeled using existing data from the literature for modeling exhaled airflow, emission rate, and size distribution. Particular focus was on the definition of the boundary conditions for the exhalation process. Turbulence was compared with experimental data for the near mouth region for 75 exhalation breathing cycles and showed the sensitivity of different modeling assumptions at the mouth inlet. The results provide insights of special interest for understanding drop dynamics in speech-like exhalation modes, modeling the mouth inlet boundary conditions, and providing data for verifying other more simplified models.
NMR chemical shift computations at second-order Møller–Plesset perturbation theory using gauge-including atomic orbitals and Cholesky-decomposed two-electron integrals
Authors: Burger Sophia , Lipparini Filippo , Gauss Jürgen , Stopkowicz Stella
Published: August 2021

We report on a formulation and implementation of a scheme to compute nuclear magnetic resonance (NMR) shieldings at second-order Møller–Plesset (MP2) perturbation theory using gauge-including atomic orbitals (GIAOs) to ensure gauge-origin independence and Cholesky decomposition (CD) to handle unperturbed and perturbed two-electron integrals. We investigate the accuracy of the CD for the derivatives of the two-electron integrals with respect to an external magnetic field and for the computed NMR shieldings, before we illustrate the applicability of our CD-based GIAO-MP2 scheme in calculations involving up to about 100 atoms and more than 1000 basis functions.
Evolution of field line helicity in magnetic relaxation
Authors: Yeates A. R. , Russell A. J. B. , Hornig G.
Published: August 2021

Plasma relaxation in the presence of an initially braided magnetic field can lead to self-organization into relaxed states that retain non-trivial magnetic structure. These relaxed states may be in conflict with the linear force-free fields predicted by the classical Taylor theory, and remain to be fully understood. Here, we study how the individual field line helicities evolve during such a relaxation, and show that they provide new insights into the relaxation process. The line helicities are computed for numerical resistive-magnetohydrodynamic simulations of a relaxing braided magnetic field with line-tied boundary conditions, where the relaxed state is known to be non-Taylor. First, our computations confirm recent analytical predictions that line helicity will be predominantly redistributed within the domain, rather than annihilated. Second, we show that self-organization into a relaxed state with two discrete flux tubes may be predicted from the initial line helicity distribution. Third, for this set of line-tied simulations we observe that the sub-structure within each of the final tubes is a state of uniform line helicity. This uniformization of line helicity is consistent with Taylor theory applied to each tube individually. However, it is striking that the line helicity becomes significantly more uniform than the force-free parameter.
The doping engineering and crystal structure of rod-like Au8Ag17 nanoclusters
Authors: Lin Xinzhang , Tang Jie , Zhang Jubo , Yang Yang , Ren Xiuqing , Liu Chao , Huang Jiahui
Published: August 2021

Alloy nanoclusters protected by ligands were widely studied due to the synergistic effect of metal atoms, and they exhibit enhanced properties in different fields, such as bio-imaging and catalysis. Herein, we obtained Au8Ag17(PPh3)10Cl10 nanoclusters via one-step simple synthesis. The atomically precise crystal structure was determined by x-ray crystallography. It is found that the rod-like Au8Ag17 nanoclusters were composed of two Au4Ag9 icosahedrons via sharing the same Ag atom. Two Au atoms occupy the center of icosahedrons, and the other six Au atoms are all at the neck sites. Four kinds of Cl–Ag connecting modes were observed in Au8Ag17 nanoclusters. Moreover, the ultraviolet–visible absorption spectrum shows that the prominent absorption peaks of Au8Ag17 nanoclusters are at ∼395 and 483 nm. This work provides a feasible strategy to synthesize alloy nanoclusters with precise composition via doping engineering.
Reproduction of vortex lattices in the simulations of rotating liquid helium-4 by numerically solving the two-fluid model using smoothed-particle hydrodynamics incorporating vortex dynamics
Authors: Tsuzuki Satori
Published: August 2021

Our recent study has shown that the representative phenomena of liquid helium-4 rotating in a cylinder could be simulated by solving the two-fluid model using smoothed-particle hydrodynamics (SPH) after reformulating the viscosity to conserve the rotational angular momentum. Specifically, the emergence of multiple parallel vortices and their rigid-body rotations were observed in our previous SPH simulations. The reported scheme is based on a classical approximation that assumes the fluid forces of both components and their interactions, with the expectation of functioning as a coarse-grained model of existing approximations that couple a microscopic model and the Navier–Stokes equation. Based on previous studies, this paper proposes an improved SPH scheme that explicitly incorporates vortex dynamics into SPH to reproduce vortex lattices, which was not possible in previous studies. Consequently, our improved scheme was observed to reproduce vortex lattices by introducing the Magnus force and interaction forces among vortices into the reformulated two-fluid model. The spinning of the vortices and rigid-body rotations were also observed. The number of vortices showed a certain agreement with Feynman's rule after the model parameter was optimized. Notably, from a scientific point of view, such vortex lattices are reproduced by the classical-mechanical approximation. We hope that our model will help physicists studying low-temperature physics find a new way of approaching this bizarre phenomenon that has attracted attention for more than 80 years.
The study of shallow water flow with bottom topography by high-order compact gas-kinetic scheme on unstructured mesh
Authors: Zhao Fengxiang , Gan Jianping , Xu Kun
Published: August 2021

A well-balanced compact high-order gas-kinetic scheme (GKS) on unstructured mesh is first developed for solving the shallow water equations with source terms. The distinguishable feature of the finite volume GKS is that based on the gas-kinetic formulation, a time-accurate gas distribution function can be constructed, from which both the fluxes and the flow variables can be explicitly evaluated at the cell interface. As a result, besides the update of cell-averaged conservative variables, the cell-averaged slopes of the flow variables can be updated as well. Equipped with both flow variables and their slopes, a fourth-order compact spatial reconstruction on unstructured mesh can be obtained as the initial condition at the beginning of each time step. For the shallow water flow, in order to preserve the well-balanced property, the advection and the source terms in the flux function have to be balanced properly. The current compact GKS achieves high-order accuracy, keeps the well-balanced property, and has super-robustness in the simulation of bore waves. The scheme is used in the shallow water flow studies, such as dam breaking and bore wave propagation. In addition, the pollution transport, morphodynamics, and bottom friction in the shallow water flow have been included in the scheme. In the end, the water discharge in the Pearl River estuary and the dam-break experiment with movable bed topography have been simulated.
Improvement of photocatalytic hydrogen evolution of La5Ti2AgS5O7 by flash sintering method
Authors: Cai Mengdie , Wang Xue , Xue Jiawei , Jiang Yong , Wei Yuxue , Cheng Qin , Chen Jingshuai , Sun Song
Published: August 2021

La5Ti2AgS5O7 (LTA) is a long-wavelength-responsive oxysulfide photocatalyst that exhibits considerable photocatalytic H2 evolution activity with an intense visible light absorption up to 570 nm. However, suppression of oxide impurities and sulfur defects when preparing LTA remains a big challenge. In this study, LTA was prepared by using a flash sintering (FS) method that allows for the synthesis of LTA (LTA-FS) with a significantly short heating period (a few seconds). The approach allowed a formation of high degree crystallinity with relatively small particle sizes without adding excessive sulfur that was employed in conventional solid-state reactions during the preparation process. Moreover, well-defined sulfur defects on the surface of LTA-FS were favorable for constructing the self-organized homojunction between the bulk and surface phases with a local built-in electric field, which is beneficial for charge separation and transfer, thus improving H2 evolution activity. The corresponding structure-to-performance relationship was further investigated by combining with the density functional theory of the electronic band structures and charge densities. This work suggests that FS may be very useful for the preparation of oxysulfide photocatalysts.
Rheotaxis of active droplets
Authors: Dwivedi Prateek , Shrivastava Atishay , Pillai Dipin , Mangal Rahul
Published: August 2021

Rheotaxis is a well-known phenomenon among microbial organisms and artificial active colloids, wherein the swimmers respond to an imposed flow. We report the first experimental evidence of upstream rheotaxis by spherical active droplets. It is shown that the presence of a nearby wall and the resulting strong flow-gradient at the droplet level is at the root of this phenomenon. Experiments with optical cells of different heights reveal that rheotaxis is observed only for a finite range of shear rates, independent of the bulk flow rate. We conjecture that the flow induced distortion of an otherwise isotropic distribution of filled/empty micelles around the droplet propels it against the flow. We also show that nematic droplets exhibit elastic stress-induced oscillations during their rheotactic flight. A promising potential of manipulating the rheotactic behavior to trap as well as shuttle droplets between target locations is demonstrated, paving way to potentially significant advancement in bio-medical applications.
Solvation of anthraquinone and TEMPO redox-active species in acetonitrile using a polarizable force field
Authors: Berthin Roxanne , Serva Alessandra , Reeves Kyle G. , Heid Esther , Schröder Christian , Salanne Mathieu
Published: August 2021

Redox-active molecules are of interest in many fields, such as medicine, catalysis, or energy storage. In particular, in supercapacitor applications, they can be grafted to ionic liquids to form so-called biredox ionic liquids. To completely understand the structural and transport properties of such systems, an insight at the molecular scale is often required, but few force fields are developed ad hoc for these molecules. Moreover, they do not include polarization effects, which can lead to inaccurate solvation and dynamical properties. In this work, we developed polarizable force fields for redox-active species anthraquinone (AQ) and 2,2,6,6-tetra-methylpiperidinyl-1-oxyl (TEMPO) in their oxidized and reduced states as well as for acetonitrile. We validate the structural properties of AQ, AQ•−, AQ2−, TEMPO•, and TEMPO+ in acetonitrile against density functional theory-based molecular dynamics simulations and we study the solvation of these redox molecules in acetonitrile. This work is a first step toward the characterization of the role played by AQ and TEMPO in electrochemical and catalytic devices.
High internal quantum efficiency of long wavelength InGaN quantum wells
Authors: Marcinkevičius Saulius , Yapparov Rinat , Chow Yi Chao , Lynsky Cheyenne , Nakamura Shuji , DenBaars Steven P. , Speck James S.
Published: August 2021

Time-resolved and quasi-cw photoluminescence (PL) spectroscopy was applied to measure the internal quantum efficiency (IQE) of c-plane InGaN single quantum wells (QWs) grown on sapphire substrates using metal-organic chemical vapor deposition. The identical temperature dependence of the PL decay times and radiative recombination times at low temperatures confirmed that the low temperature IQE is 100%, which allowed evaluation of the absolute IQE at elevated temperatures. At 300 K, the IQE for QWs emitting in green and green–yellow spectral regions was more than 60%. The weak nonradiative recombination in QWs with a substantial concentration of threading dislocations and V-defects (∼2 × 108 cm−2) shows that these extended defects do not notably affect the carrier recombination.
Fluid dynamics of respiratory droplets in the context of COVID-19: Airborne and surfaceborne transmissions
Authors: Katre Pallavi , Banerjee Sayak , Balusamy Saravanan , Sahu Kirti Chandra
Published: August 2021

The World Health Organization has declared COVID-19 a global pandemic. Several countries have experienced repeated periods of major spreading over the last two years. Many people have lost their lives, employment, and the socioeconomic situation has been severely impacted. Thus, it is considered to be one of the major health and economic disasters in modern history. Over the last two years, several researchers have contributed significantly to the study of droplet formation, transmission, and lifetime in the context of understanding the spread of such respiratory infections from a fluid dynamics perspective. The current review emphasizes the numerous ways in which fluid dynamics aids in the comprehension of these aspects. The biology of the virus, as well as other statistical studies to forecast the pandemic, is significant, but they are not included in this review.
Monometallic and Multimetallic Zinc Complexes of 2,7-Bis(2-pyridyl)-1,8-naphthyridine
Authors: Stevens Michael A. , Hall Peter D. , Colebatch Annie L.
Published: August 2021

A series of zinc complexes of 2,7-bis(2-pyridyl)-1,8-naphthyridine (BPNP) has been synthesised and characterised by single crystal X-ray diffraction and solution state NMR spectroscopic studies. Reactions of BPNP with zinc acetate and zinc chloride were found to give mononuclear complexes of the form [Zn(BPNP)X2] (X = OAc, Cl), whereas reactions with zinc triflate led to a mixture of products. Several of these were identified crystallographically as [Zn(BPNP-H)(H2O)4](OTf)3 and [Zn(BPNP-H)(NCMe)(OTf)2]OTf, in which protonation of one pyridyl group occurred, and the dimeric species [Zn2(BPNP)4(μ-H2O)2](OTf)4. A trimetallic complex [Zn3(μ2-BPNP)(μ2-OAc)3(OAc)2(μ3-OH)] was also isolated from reactions involving zinc acetate, and demonstrates the ability of BPNP to coordinate two zinc atoms in the adjacent binding pockets.
Photosynthetic characteristics and leaf litter production of mangrove forests in Trang, southern Thailand
Authors: Cadiz Pablina , Sinutok Sutinee , Chotikarn Ponlachart
Published: August 2021

The aim of this study was to investigate the photosynthetic performance and litter production of planted (PLA) and natural (NAT) mangroves in Trang, southern Thailand. Relative chlorophyll content and other photosynthetic parameters, such as photosynthetic efficiency of Photosystem II (Phi2), yield of non-regulatory energy dissipation (PhiNO), yield of non-photochemical quenching (PhiNPQ) and quenching due to non-photochemical dissipation of absorbed light energy (NPQt), and litter fall production were determined and compared between two mangrove stands. Measurements of photosynthetic parameters were made using PhotosynQ to assess the health of the community structure in both stands. The assumption of this study, namely that there would be no significant difference in any photosynthetic parameter measured between the two stands, was confirmed using t-test with unequal variances confirmed (P > 0.05 for all). Changes occurred quarterly and in sites with different species. In terms of litter production, significant differences were found according to stand (P < 0.001), season (P < 0.05) and site (Sikao, F3,129 = 4.357, P < 0.01; Kantang, F3,190 = 3.243, P < 0.01). PLA stands demonstrated similar photosynthetic characteristics to NAT stands. This study established the effects of land use changes on PLA mangroves (planted in an abandoned shrimp pond). The overall significance of the study is in highlighting the positive outcomes of mangrove restoration, particularly in degraded mangrove stands due to land use change.