bluuebunny/crossref_metadata_2025 huggingface dataset:
Total Synthesis and Anti-inflammatory Activity of Stemoamide-Type Alkaloids Including Totally Substituted Butenolides and Pyrroles
Authors: Soda Yasuki , Sugiyama Yasukazu , Sato Shunsei , Shibuya Kana , Saegusa Junya , Matagawa Tomoe , Kawano Sayaka , Yoritate Makoto , Fukaya Keisuke , Urabe Daisuke , Oishi Takeshi , Mori Kento , Simizu Siro , Chida Noritaka , Sato Takaaki
Published: September 2022

Totally substituted butenolide including two tetrasubstituted olefins is a distinct structural motif seen in Stemona alkaloids, but efficient methods for its synthesis are not well developed. As an ongoing program aimed at the collective total synthesis of the stemoamide group, we report a stereodivergent method to give either (E)- or (Z)-totally substituted butenolide from the same intermediate. While AgOTf­-mediated elimination via an E1-type mechanism results in the formation of the kinetic (Z)-tetrasubstituted olefin, subsequent TfOH-mediated isomerization gives the thermodynamic (E)-tetrasubstituted olefin. The pyrrole ring is another important structure found in Stemona alkaloids. The direct oxidation of pyrrolidine rings with MnO2 and careful purification gives the pyrrole groups without isomerization of the stereocenter in the lactone group. These two methods enabled us to synthesize a series of stemoamide-type alkaloids including tricyclic, tetracyclic, and pentacyclic frameworks. The anti-inflammatory activities by inhibition of iNOS expression in macrophage cell line RAW264.7 indicate that the most potent anti-inflammatory compounds without cytotoxicity are protostemonines, which consist of pentacyclic frameworks including the totally substituted butenolide.
Analysis of Benign Retroperitoneal Schwannomas: A Single-center Experience
Authors: Tang Maosheng , Liu Wenqing , Chen Xiaobing , Zou Boyuan , Liu Shibo , Xiao Mengmeng , Luo Chenghua
Published: September 2022

Background Retroperitoneal schwannomas are rare. The purpose of this study was to present our experience with the diagnosis and treatment of 67 such tumors.

Methods We retrospectively analyzed 67 patients with retroperitoneal schwannoma admitted to the Peking University International Hospital from 2015 to 2021.

Results Thirty-seven of the 67 patients had no obvious clinical symptoms. Complete excision was obtained in 62 and subtotal excision in 5 cases. In7 cases, tumor resection was combined with organ resection. The intraoperative blood loss was 300 ml (20–9,000 ml), the maximum size of the tumor was 9 cm (2.5–26 cm), and postoperative complication occurred in six cases (9.0%). Compared with abdominal retroperitoneal tumors, pelvic retroperitoneal tumors had larger tumor volume, more bleeding, higher proportion of block resection, and longer postoperative hospitalization time (p < 0.05). The residual mass progressed slowly in five patients with subtotal resection, and no obvious malignant transformation occurred.

Conclusion Complete resection of a retroperitoneal schwannoma can achieve a good long-term prognosis. Residual tumor after surgery progresses slowly and rarely become malignant. We recommend early resection after the discovery of a pelvic retroperitoneal schwannoma.
UPLC/Q-TOF-MS-based Metabolomics Study of the Antiosteoporosis Effects of Vaccarin in Ovariectomized Mice
Authors: Song Fangming , Xie Tianyu , Liu Xi , Chin Bonnie , Luo Xiaoting , Liao Shijie , Feng Wenyu , He Mingwei , Huang Nenggan , Su Zhiheng , Liu Yun ,   Abu·Moro
Published: September 2022

Osteoporosis is a systemic and metabolic bone disease that usually occurs in postmenopausal women, which mainly manifests as bone loss and increased bone fragility that both facilitate
fracture. However, few drugs for osteoporosis have shown good efficacy and limited side effects. Vaccarin has demonstrated its antiosteoporosis effects by inhibiting the formation and
osteolytic activities of osteoclasts in our previous investigation. In this study, multivariate statistical analysis and ultrahigh-performance liquid chromatography and quadrupole
time-of-flight tandem mass spectrometry were used to analyze the serum metabolites of ovariectomized mice treated with or without vaccarin. As a result, 9 serum metabolites were identified
as biomarkers. The metabolic levels of 3 crucial biomarkers, namely, lysophosphatidylcholine [22 : 6, (4Z, 7Z, 10Z, 13Z, 16Z, 19Z)], 1-linoleoylglycerophosphocholine and
1-palmitoyl-Sn-glycero-3-phosphocholine, that were correlated with glycerophospholipid metabolism increased and then decreased significantly after vaccarin treatment. Molecular docking
analysis and osteoclasts differentiation experiment further revealed that vaccarin may bind with phospholipase A2 and downregulated its activity to reduce the osteoclastogenesis. Therefore,
the occurrence of osteoporosis is closely related with glycerophospholipid metabolism disorders, and vaccarin exerts antiosteoporosis effects by reducing the levels of glycerophospholipid
metabolites.
Novel Selection Tools in Rhinoplasty Patients
Authors: Lekakis Garyfalia , Constantian Mark , Most Sam P. , Picavet Valerie , Hellings Peter William
Published: September 2022

With no consensus document or guideline to help us compute the psychological make-up of rhinoplasty candidates and in the light of new perspectives of some key opinion leaders in the field of patient selection, the goals of this article are to offer a glimpse of the current literature together with the knowledge gaps, introduce some new tools for the preoperative consultation, help us identify who among our patients is at greatest risk for a poor outcome, and explain how childhood trauma can be linked to body shame and postoperative dissatisfaction.
Biomechanics of Septal L-Strut on Lamb Head Models
Authors: Erol Ozan , Soto-Galindo Germán Armando , Apaydin Fazil
Published: September 2022

It is very crucial to know the biomechanics of the septal cartilage and adjacent structures during septoplasty. The aim of this study was to investigate the strength changes of different L-strut models after mucoperichondrium elevation, application of septal extension grafts and spreader grafts on an experimental lamb model. Ten lamb heads were dissected according to a dissection protocol and septal resistances were measured with the newton meter at six zones. Three different L-strut types were designed, and all the L-strut models were created at different widths of 15mm, 10mm, and 5mm. In addition, effects of two different types of septal extension grafts and spreader grafts were compared. After mucoperichondrium elevation and harvesting the septum cartilage, there was a significant decrease in the septum resistance (p <0.05). As the width of the L-strut decreased, the septum strength decreased significantly (p <0.05). There was no significant difference between three chondrotomy types at different widths (p >0.05). There was no significant difference between the overlapping SEG and end-to-end SEG in terms of septum resistance (p >0.05). This was the first study to measure septal resistance in lamb heads. The mucoperichondrium and L-strut width were important structures for maintaining septal resistance. Chondrotomy style was not crucial, but as the width of the L-strut increased, the septal resistance increased. The septal extension grafts regardless of suturing style and the spreader grafts added strength to the caudal septum.
Tumors of the Spine: When Can Biopsy Be Avoided?
Authors: Weber Marc-André , Bazzocchi Alberto , Nöbauer-Huhmann Iris-M.
Published: September 2022

Regarding osseous tumors of the spine, characteristic morphology is encountered in hemangioma of the vertebral body, osteoid osteoma (OO), osteochondroma, Paget's disease, and bone islands. In these cases, radiologic imaging can make a specific diagnosis and thereby avoid biopsy, especially when the radiologist has chosen the correct imaging modality to establish the diagnosis, such as thin-slice computed tomography in suspected OO. A benign lesion is suggested by a high amount of fat within the lesion, the lack of uptake of the contrast agent, and a homogeneous aspect without solid parts in a cystic tumor. Suspicion of malignancy should be raised in spinal lesions with a heterogeneous disordered matrix, distinct signal decrease in T1-weighted magnetic resonance imaging, blurred border, perilesional edema, cortex erosion, and a large soft tissue component. Biopsy is mandatory in presumed malignancy, such as any Lodwick grade II or III osteolytic lesion in the vertebral column. The radiologist plays a crucial role in determining the clinical pathway by choosing the imaging approach wisely, by narrowing the differential diagnosis list, and, when characteristic morphology is encountered, by avoiding unnecessary biopsies.
Influence on Therapeutic Decision-Making of Supine and Standing Radiographs after Traumatic Thoracolumbar Fracture in the Elderly
Authors: Noguera-Alonso Laura , Vilà-Canet Gemma , De Caso-Rodriguez Julio , Da Ponte-Prieto Ariadna , Perez-Romera Ana Belen , Velazquez-Fragoso Juan Jose
Published: September 2022

Background A standing X-ray is recommended for decision-making relative to the therapy for a traumatic thoracolumbar fracture (TLF). However, standing X-ray management can be demanding in elderly patients because of pain. The goal of this study was to determine whether supine radiograph is sufficient for proper therapeutic decision-making in patients older than 65 years with acute stable traumatic TLF.

Methods Patients older than 65 years who came to the emergency department diagnosed with an acute and stable traumatic vertebral fracture between T10 and L3 (both included) were included in the study. Initially, all the patients were studied with a supine radiograph and computed tomography (CT) scan. If the TLF was stable, a standing radiograph was performed. Segmental kyphosis (SK) and visual analog scale (VAS) score were collected and compared in both the supine and standing X-ray projections.

Results Twenty-seven patients with a mean age of 76.39 (range: 65–93) years were included; most were females. The mean supine SK was 10.14degrees (SD±7.22degrees). It increased to 12.97 (SD±8.61degrees) in the standing projection (p<0.001). In 37.1% of the patients, the SK increased from 13.22degrees (SD±7.21degrees) in supine X-ray to 19.96degrees (SD±5.34degrees) in the standing position in this group. When the initial supine projection showed an SK of ≥10degrees, the mean SK observed in the standing X-ray increased to 20.5degrees (SD±5.30, p=0.321).

Conclusion Stable traumatic TLF in patients older than 65 years showing ≥10degrees of SK in supine radiography may benefit from a standing radiography to make a proper therapeutic decision.
Disseminated Intravascular Coagulation: The Past, Present, and Future Considerations
Authors: Iba Toshiaki , Levi Marcel , Thachil Jecko , Levy Jerrold H.
Published: September 2022

Disseminated intravascular coagulation (DIC) has been understood as a consumptive coagulopathy. However, impaired hemostasis is a component of DIC that occurs in a progressive manner. The critical concept of DIC is systemic activation of coagulation with vascular endothelial damage. DIC is the dynamic coagulation/fibrinolysis disorder that can proceed from compensated to decompensated phases, and is not simply impaired hemostasis, a misunderstanding that continues to evoke confusion among clinicians. DIC is a critical step of disease progression that is important to monitor over time. Impaired microcirculation and subsequent organ failure due to pathologic microthrombi formation are the pathophysiologies in sepsis-associated DIC. Impaired hemostasis due to coagulation factor depletion from hemodilution, shock, and hyperfibrinolysis occurs in trauma-associated DIC. Overt-DIC diagnostic criteria have been used clinically for more than 20 years but may not be adequate to detect the compensated phase of DIC, and due to different underlying causes, there is no “one-size-fits-all criteria.” Individualized criteria for heterogeneous conditions continue to be proposed to facilitate the diagnosis. We believe that future research will provide therapeutics using new diagnostic criteria. Finally, DIC is also classified as either acute or chronic, and acute DIC results from progressive coagulation activation over a short time and requires urgent management. In this review, we examine the advances in research for DIC.
Transient absorption spectroscopy shines light on photocatalysts
Authors: Thompson Avery
Published: September 2022

Spectroscopy method can reveal relaxation pathways and inform design of new compounds
Spin-wave frequency combs
Authors: Hula T. , Schultheiss K. , Gonçalves F. J. T. , Körber L. , Bejarano M. , Copus M. , Flacke L. , Liensberger L. , Buzdakov A. , Kákay A. , Weiler M. , Camley R. , Fassbender J. , Schultheiss H.
Published: September 2022

We experimentally demonstrate the generation of spin-wave frequency combs based on the nonlinear interaction of propagating spin waves in a microstructured waveguide. By means of time- and space-resolved Brillouin light scattering spectroscopy, we show that the simultaneous excitation of spin waves with different frequencies leads to a cascade of four-magnon scattering events, which ultimately results in well-defined frequency combs. Their spectral weight can be tuned by the choice of amplitude and frequency of the input signals. Furthermore, we introduce a model for stimulated four-magnon scattering, which describes the formation of spin-wave frequency combs in the frequency and time domain.
Nucleation of stem cell domains in a bistable activator–inhibitor model of the shoot apical meristem
Authors: Battogtokh Dorjsuren , Tyson John J.
Published: September 2022

Shoot apical meristems (SAMs) give rise to all above-ground tissues of a plant. Expansion of meristematic tissue is derived from the growth and division of stem cells that reside in a central zone of the SAM. This reservoir of stem cells is maintained by expression of a transcription factor WUSCHEL that is responsible for the development of stem cells in the central zone. WUSCHEL expression is self-activating and downregulated by a signaling pathway initiated by CLAVATA proteins, which are upregulated by WUSCHEL. This classic activator–inhibitor network can generate localized patterns of WUSCHEL activity by a Turing instability provided certain constraints on reaction rates and diffusion constants of WUSCHEL and CLAVATA are satisfied, and most existing mathematical models of nucleation and confinement of stem cells in the SAM rely on Turing's mechanism. However, Turing patterns have certain properties that are inconsistent with observed patterns of stem cell differentiation in the SAM. As an alternative mechanism, we propose a model for stem cell confinement based on a bistable-switch in WUSCHEL–CLAVATA interactions. We study the bistable-switch mechanism for pattern formation in a spatially continuous domain and in a discrete cellularized tissue in the presence of a non-uniform field of a rapidly diffusing hormone. By comparing domain formation by Turing and bistable-switch mechanisms in these contexts, we show that bistable switching provides a superior account of nucleation and confinement of the stem cell domain under reasonable assumptions on reaction rates and diffusion constants.
Complex permittivity measurement technique using metamaterial broadside coupled split ring resonator
Authors: Sebastian Anju , Joseph Dona , P. V. Aswathi , K. Simon Sikha , C Bindu , V. P. Joseph , Andrews Jolly
Published: September 2022

A simple and effective method for the determination of complex permittivity of dielectric materials at microwave frequencies using a Broadside Coupled Split Ring Resonator (BCSRR) metamaterial structure is presented. A single BCSRR unit cell placed between the transmitting and receiving probes of a Vector Network Analyzer (VNA) is used as the test probe. Resonance frequencies and bandwidths of transmission curves, measured with and without the sample placed over the BCSRR test probe, are used to determine the real and imaginary parts of the complex permittivity by treating the BCSRR as an LC resonant circuit. Relevant equations connecting equivalent capacitance and resonance frequencies are derived from the basic equivalent circuit parameters of the BCSRR through a quasi-static analysis by considering the fringing fields in its vicinity, especially on the top and bottom. Accuracy of the theoretical formula derived for determining the complex permittivity using the BCSRR is verified through experiments and simulations.
Evidence for strain and a structural reset in Pd40Ni40P20 bulk metallic glass
Authors: Stringe Mark , Rösner Harald , Wilde Gerhard
Published: September 2022

Individual heat treatments on bulk Pd40Ni40P20 metallic glass samples were performed in a differential scanning calorimeter to either activate mainly β or both α and β relaxation processes as well as heating into the supercooled liquid. The medium-range order of the final amorphous structure was investigated by fluctuation electron microscopy and compared with that of the as-cast state. The results indicate that first, a defined structural reset was achieved by heating into the supercooled liquid. Second, the annealed states exhibit a lower volume fraction of medium-range order, and third, the strain is increased due to the reduction of excess volume after annealing.
Absence of spin-mixed states in ferrimagnet Yttrium iron garnet
Authors: Cheshire D. , Bencok P. , Gianolio D. , Cibin G. , Lazarov V. K. , van der Laan G. , Cavill S. A.
Published: September 2022

The spectroscopic g-factor of epitaxial thin film Yttrium Iron Garnet (YIG) has been studied using a combination of ferromagnetic resonance spectroscopy and x-ray magnetic circular dichroism. The values obtained by the two techniques are found, within experimental error, to be in agreement using Kittel's original derivation for the g-factor. For an insulating material with an entirely Fe3+ configuration, a spin mixing correction to Kittel's derivation of the spectroscopic g-factor, as recently shown by Shaw et al. [Phys. Rev. Lett. 127, 207201 (2021)] for metallic systems, is not required and demonstrates that the spin mixing parameter is small in YIG due to negligible spin–orbit coupling.
Fabrication of multi-layer graphene by repeated transfer
Authors: Kawata Kazunori , Kawaki Syunsuke , Nakamura Takako , Koga Yoshinori , Hasegawa Masataka
Published: September 2022

Multi-layer graphene was formed by repeated transfer onto a silicon oxide substrate, and changes in its doping characteristics were observed. The structure of multi-layer graphene was investigated in comparison with pyrolytic graphite with a turbostratic structure. Single-layer graphene is doped due to the influence of the silicon oxide substrate, and the influence of poly(methyl methacrylate) and water residue, which are used for the transfer, is small. Graphene in the first layer suppresses the influence of the silicon oxide substrate, and the second and subsequent layers are almost unaffected. By repeating the transfer and stacking, multi-layer graphene approaches ideal turbostratic graphite.
Single-shot off-axis full-field optical coherence tomography
Authors: Seromenho Emmanuel Martins , Marmin Agathe , Facca Sybille , Bahlouli Nadia , Perrin Stephane , Nahas Amir
Published: September 2022

Full field optical coherence tomography (FF-OCT) enables high-resolution in-depth imaging within turbid media. In this work, we present a simple approach which combines FF-OCT with off-axis interferometry for reconstruction of en-face images. With low spatial and temporal coherence illumination, this method is able to extract an FF-OCT image from only one interference acquisition. This method is described, and the proof-of-concept is demonstrated through the observation of scattering samples such as organic and ex vivo biomedical samples.
Improvement of deposition characteristics of silicon oxide layers using argon-based atmospheric-pressure very high-frequency plasma
Authors: Kakiuchi Hiroaki , Ohmi Hiromasa , Takeda Seiya , Yasutake Kiyoshi
Published: September 2022

We have investigated the deposition characteristics of silicon oxide (SiOx) layers in atmospheric pressure (AP) argon (Ar)-based plasma at a substrate temperature of 120 °C. A 150 MHz, very high-frequency (VHF) power is effectively used for exciting stable and uniform hexamethyldisiloxane (HMDSO)-oxygen (O2) fed plasma under AP. The microstructure of the SiOx layers is discussed in comparison with that by using helium (He)-based plasma. In the case of depositions with He/HMDSO/O2 plasma, SiO2-like films with uniform thickness, which have sufficient compactness to be used as the gate dielectrics of bottom-gate thin film transistors, can be obtained by moving substrate at a constant speed during the plasma operation. However, the decrease in the total gas flow rate (increase in the gas residence time in the plasma) causes the increase in the participation of nanoparticles to the film growth, which might result in the deterioration of film quality. Shortening the electrode length is effective for avoiding the incorporation of nanoparticles into the growing SiOx films. On the other hand, when Ar/HMDSO/O2 plasma is used, no deterioration of film compactness is observed irrespective of the gas flow rate. The results obtained in this study demonstrate the effectiveness of the VHF excitation of AP plasma on the generation of stable and uniform glow discharge without using He, which will lead to the development of a highly efficient and reduced cost formation process of good-quality SiOx films.
Electronic transport studies of Ag-doped Bi2Se3 topological insulator
Authors: Sharma Shailja , Kumar Shiv , Kumar Amit , Shimada Kenya , Yadav C. S.
Published: September 2022

The structural, magnetotransport, and angle-resolved photoemission spectroscopy (ARPES) of Ag-doped Bi2Se3 single crystals are presented. Temperature dependent resistivity exhibits metallic behavior with a slope change above 200 K for Ag-doped Bi2Se3. The magnetoresistance shows positive quadratic dependence at low fields satisfying Kohler's rule. Hall resistivity measurement shows that electrons are dominant charge carriers. Furthermore, these results agree well with the ARPES spectra observed at T = 20 K, where the Fermi level lies inside the bulk conduction band. The Dirac point of the topological surface states is shifted toward higher binding energy (∼0.12 eV) for Ag-doped samples as compared to pristine Bi2Se3.
Ambipolarity of diluted hydrogen in wide-gap oxides revealed by muon study
Authors: Hiraishi M. , Okabe H. , Koda A. , Kadono R. , Hosono H.
Published: September 2022

Muon spin rotation has long been recognized as one of the few methods for experimentally accessing the electronic state of dilute hydrogen (H) in semiconductors and dielectrics, where muon behaves as a pseudo-H (designated by the elemental symbol Mu). Meanwhile, predictions on the electronic state of H in these materials by density functional theory (DFT) do not always agree with the observed states of Mu. Most notably, Mu frequently occurs in wide-gap oxides simultaneously in a neutral (Mu0) and a diamagnetic state (Mu+ or Mu−), which DFT calculations do not explain; they predict that H is stable only in a diamagnetic state with the polarity determined by the equilibrium charge-transition level (E+/−) vs the Fermi level. To address this issue, we developed a semi-quantitative model that allows a systematic understanding of the electronic states reported for Mu in the majority of oxides. Our model assumes that muons interact with self-induced excitons to produce relaxed-excited states corresponding to donor-like (MuD) and/or acceptor-like (MuA) states and that these states correspond to the non-equilibrium electronic level (E+/0 or E0/−) predicted by DFT calculations for H. The known experimental results are then explained by the relative position of E+/0 and E0/− in the host’s energy band structure. In addition, the model sheds new light on the polaron-like nature of the electronic states associated with shallow donor Mu complexes.
Improved resistance to oxidation of Ge-doped Fe3O4 thin films with cation excess composition using a sputtering target of FeO
Authors: Abe Seishi
Published: September 2022

The correlation between the composition of Ge-doped Fe3O4 thin films, including excess cation from stoichiometry, and resistance to oxidation during heat treatment in air was investigated. The films were prepared on glass substrates by radio-frequency sputtering using a target of Ge chips set on a ceramic FeO disk. Ge-doped Fe3O4 films with cation excess compositions were obtained by optimizing the deposition conditions, and five of these samples with Ge concentrations ranging from 0 to 4.3 at. % were heat treated in air at 673 K for up to 113 days. The magnetization after heat treatment was largest at 2.4 at. % Ge, which was larger than that of Fe3−δO4 (δ = 0.054) doped with Ge thin film. In other words, it is clear that the resistance to oxidation is better in the cation excess composition.
Continuous amplitude control of second harmonic waves from the metasurfaces through interference paths
Authors: Liu Xuan , Tang Yutao , Li Yang , Hu Zixian , Deng Junhong , Li Guixin
Published: September 2022

Nonlinear plasmonic metasurfaces represent a promising platform for generating and controlling the multiple degrees of freedom of harmonic waves at the subwavelength scale. Among various functionalities, the amplitude control of the harmonic waves is usually achieved by varying the fundamental frequency and the pumping power. However, these kinds of methods lack the ability to control the energy distributions of the nonlinear waves at different diffraction orders. Here, we report the continuous intensity control of the harmonic waves from the plasmonic metasurfaces through interference paths. The metasurfaces consist of geometric phase controlled gold meta-atoms with threefold rotational symmetry. By controlling the relative phase of two neighboring metasurface paths, the intensity of the diffracted second harmonic waves can be artificially modulated. Our findings suggest that the conventional interference technique represents a powerful route for controlling the radiation of the nonlinear waves from sub-wavelength meta-atoms and may have great applications in developing ultra-compact nonlinear optical sources.
A review on nature-inspired gating membranes: From concept to design and applications
Authors: Bazyar Hanieh , Moultos Othonas A. , Lammertink Rob G. H.
Published: September 2022

Nature has been a constant source of inspiration for technological developments. Recently, the study of nature-inspired materials has expanded to the micro- and nanoscale, facilitating new breakthroughs in the design of materials with unique properties. Various types of superhydrophobic surfaces inspired by the lotus/rice leaf are examples of nature-inspired surfaces with special wettability properties. A new class of functional surfaces whose design is inspired by the pitcher plant are the slippery liquid-infused porous surfaces (SLIPS). This Review summarizes the properties, design criteria, fabrication strategies, and working mechanisms of both surfaces with specific focus on SLIPS. The applications of SLIPS in the field of membrane technology [slippery liquid-infused membranes (SLIMs)] are also reviewed. These membranes are also known as liquid gating membranes due to the gating functionality of the capillary-stabilized liquid in the membrane pores leading to a smart gating mechanism. Similar to the gating ion channels in biological systems, the pores open and close in response to the ambient stimuli, e.g., pressure, temperature, and ions. Different types of stimuli-responsive smart gating membranes are introduced here, and their properties and applications are reviewed in detail. Finally, challenges and perspectives on both SLIPS and smart gating membranes are discussed. This Review provides a thorough discussion and practical applications of nature-inspired functional surfaces and membranes to pave the way for future research and further developments in this emerging field.
A study of Novec 649TM fluid jets injected into sub-, trans-, and supercritical thermodynamic conditions using planar laser induced fluorescence and elastic light scattering diagnostics
Authors: Kasapis Georgios , Yang Shangze , Falgout Zachary , Linne Mark
Published: September 2022

This paper describes laser imaging experiments on steady, rotationally symmetric, laminar jets aimed at observation of the interface between an injected liquid and the surrounding gas under subcritical, transcritical, and supercritical conditions. A steady, laminar flow of fluoroketone enters a chamber of high pressure and temperature nitrogen, allowing direct examination of the interface as it evolves with flow time (i.e., axial position in the chamber). Vapor/liquid equilibrium calculations identifying the critical locus for mixtures of fluoroketone and nitrogen are used to define six test cases, covering the range from entirely subcritical to entirely supercritical states. Planar laser induced fluorescence (PLIF) and planar elastic light scattering (PELS) imaging are applied to these jets, to image mixture fraction (via PLIF) simultaneously with the detection of the interface strength (via PELS). Temperature distributions are acquired using thermocouples. Evidence for the evolution of the interface, and for supercritical states, is presented and discussed.
Effect of drag models on hydrodynamic behaviors of slurry flows in horizontal pipes
Authors: Liu Weihuang , He Yanping , Li Mingzhi , Huang Chao , Liu Yadong
Published: September 2022

The Eulerian–Eulerian method is efficient when dealing with liquid–solid slurry flows containing a large number of particles, but its reliability relies on an accurate description of liquid–particle interaction for which numerous interphase drag models have been proposed. However, the performance of these models has not been systematically evaluated when applied to slurry flows. In this study, slurries in horizontal pipes under various flow conditions are simulated using the Eulerian–Eulerian method. Six commonly used drag models, such as the Schiller–Naumann, Wen–Yu, Gibilaro, Gidaspow, Syamlal–O'Brien, and Huilin–Gidaspow models, are assessed based on their predictions of streamwise velocity, secondary flow, solid concentration, and liquid turbulent kinetic energy. Under normal operations, all models provide similar streamwise velocities and secondary flow patterns. However, the Schiller–Naumann model presents an intensified secondary flow and a flattened solid concentration profile. All models perform poorly for the solid concentration distribution, which may be corrected by considering the overall mean solid concentration. Additionally, the Wen–Yu model, which has previously been thought applicable only for dilute systems, behaves very closely to the Gidaspow model, which is usually recommended for dense fluidized beds.
Fractional-unit-cell-doped spinel/perovskite oxide interfaces with switchable carrier conduction
Authors: Gan Yulin , Zhang Yu , Jiang Sicong , Zhang Hongrui , Guan Xiangxiang , Yan Lei , Hu Fengxia , Yu Richeng , Sun Jirong , Ding Hong , Yang Kesong , Chen Yunzhong , Shen Baogen
Published: September 2022

The two-dimensional hole gas (2DHG) at the polar LaAlO3/SrTiO3 interface remains elusive. Different from isostructural perovskite-type interfaces, the spinel/perovskite heterointerface of γ-Al2O3/SrTiO3 (GAO/STO) enables us to control interfacial states with sub-unit-cell precision. Herein, we present the epitaxial growth of fractionally doped GAO/STO heterointerfaces, where GAO is precisely doped on the scale of 1/4-unit-cell (0.2 nm) by ferromagnetic Fe3O4 and nonmagnetic ZnO atomic layers. Notably, the conduction of the engineered interfaces depends critically on the position of the dopant, where a coexistence of electron and hole conduction is measured at even sublayer-doped GAO/STO interfaces. First-principles density functional theory calculations indicate that electron conductivity is from the interfacial TiO2 layers of the STO substrate, while the hole conductivity is from the Zn-doped GAO film. The presence of hole conduction can be explained from the alternating structural feature of a doped layer without oxygen vacancies. This work sheds additional insight on the emergence of 2DHG at oxide interfaces and provides opportunities for atomically engineered oxide interfaces with non-isostructural layers.
Pinch-off dynamics of double-emulsion droplets with/without the influence of interfacial coupling effect
Authors: Wang Xiang , Li Dezhi , Pang Yan , Liu Zhaomiao
Published: September 2022

Pinch-off dynamics of double-emulsion droplets is experimentally studied. Pure liquid systems with different combinations of three-phase viscosities are considered to particularly reveal the thinning mechanisms and their variation characteristics when the interfacial coupling effect exists. The whole breakup process is analyzed at first, and the pinch-off stage governed by the interfacial tension is confirmed. The scaling law of the minimum neck width is constructed to make quantitative comparisons with the conventional theories obtained from single emulsions. The influence of the coupling effect on the thinning dynamics is discussed by sequentially varying the viscosity of one single phase of the liquid system. With the coupling effect, it is found that the rapid collapsing occurs in advance due to the superposition of the Laplace pressure differences at the minimum neck width. The thinning rate of the outer droplet follows that of the inner droplet until the breakup of the inner droplet, after which the thinning process of the outer droplet quickly coincides with the uncoupled case as the disturbances damp out by relatively high viscosity. On the contrary, the subsequent thinning dynamics would be changed when the low-viscosity liquid is used.
Inertial migration of soft particles initially evenly spaced along the flow direction in a channel
Authors: Huang Lizhong , Lin Jianzhong , Wang Ruijin , Shao Chun
Published: September 2022

The inertial migration of two-dimensional soft particles initially distributed uniformly in channel flow is numerically studied by employing an immersed-boundary lattice Boltzmann method coupled with a finite element method. To model a soft particle, a capsule with an elastic membrane separating the liquid inside from the outside is used. Validation tests show excellent agreement with previous numerical results of other researchers. Then, the effects of the number of capsules Np, the bending stiffness Eb, the initial position Y0′, and the Reynolds number Re on the dynamics of the capsules in channel flow are investigated in detail. Interestingly, we discover a new regime (labeled as regime E) in which a few capsules situated near the channel centerline travel much faster than the rest. Moreover, regime E is more prone to vanishing while the capsules are very soft. The normalized overall lateral position of the capsules σ increases almost linearly with Np when the capsules stabilize in a single-line particle train (designated as regime A). We also make an effort to explain the formation of the capsule deformation shape in regime A. The steady dynamics of a single capsule depend on whether the initial position is on the channel centerline. However, if the capsule is not released on the channel centerline, the steady capsule dynamics are independent of the initial position. But, it is not true for multiple capsule dynamics. These findings may help understand the inertial migration of capsules in channel flow.
Structure of IMPORTIN-4 bound to the H3–H4–ASF1 histone–histone chaperone complex
Authors: Bernardes Natália Elisa , Fung Ho Yee Joyce , Li Yang , Chen Zhe , Chook Yuh Min
Published: September 2022

IMPORTIN-4, the primary nuclear import receptor of core histones H3 and H4, binds the H3–H4 dimer and histone chaperone ASF1 prior to nuclear import. However, how H3–H3–ASF1 is recognized for transport cannot be explained by available crystal structures of IMPORTIN-4–histone tail peptide complexes. Our 3.5-Å IMPORTIN-4–H3–H4–ASF1 cryoelectron microscopy structure reveals the full nuclear import complex and shows a binding mode different from suggested by previous structures. The N-terminal half of IMPORTIN-4 clamps the globular H3–H4 domain and H3 αN helix, while its C-terminal half binds the H3 N-terminal tail weakly; tail contribution to binding energy is negligible. ASF1 binds H3–H4 without contacting IMPORTIN-4. Together, ASF1 and IMPORTIN-4 shield nucleosomal H3–H4 surfaces to chaperone and import it into the nucleus where RanGTP binds IMPORTIN-4, causing large conformational changes to release H3–H4–ASF1. This work explains how full-length H3–H4 binds IMPORTIN-4 in the cytoplasm and how it is released in the nucleus.
Synaptotagmin rings as high-sensitivity regulators of synaptic vesicle docking and fusion
Authors: Zhu Jie , McDargh Zachary A. , Li Feng , Krishnakumar Shyam S. , Rothman James E. , O’Shaughnessy Ben
Published: September 2022

Synchronous release at neuronal synapses is accomplished by a machinery that senses calcium influx and fuses the synaptic vesicle and plasma membranes to release neurotransmitters. Previous studies suggested the calcium sensor synaptotagmin (Syt) is a facilitator of vesicle docking and both a facilitator and inhibitor of fusion. On phospholipid monolayers, the Syt C2AB domain spontaneously oligomerized into rings that are disassembled by Ca
2+
, suggesting Syt rings may clamp fusion as membrane-separating “washers” until Ca
2+
-mediated disassembly triggers fusion and release [J. Wang et al.,
Proc. Natl. Acad. Sci. U.S.A.
111, 13966–13971 (2014)].). Here, we combined mathematical modeling with experiment to measure the mechanical properties of Syt rings and to test this mechanism. Consistent with experimental results, the model quantitatively recapitulates observed Syt ring-induced dome and volcano shapes on phospholipid monolayers and predicts rings are stabilized by anionic phospholipid bilayers or bulk solution with ATP. The selected ring conformation is highly sensitive to membrane composition and bulk ATP levels, a property that may regulate vesicle docking and fusion in ATP-rich synaptic terminals. We find the Syt molecules hosted by a synaptic vesicle oligomerize into a halo, unbound from the vesicle, but in proximity to sufficiently phosphatidylinositol 4,5-bisphosphate (PIP2)-rich plasma membrane (PM) domains, the PM-bound trans Syt ring conformation is preferred. Thus, the Syt halo serves as landing gear for spatially directed docking at PIP2-rich sites that define the active zones of exocytotic release, positioning the Syt ring to clamp fusion and await calcium. Our results suggest the Syt ring is both a Ca
2+
-sensitive fusion clamp and a high-fidelity sensor for directed docking.
Linearized boundary control method for an acoustic inverse boundary value problem
Authors: Oksanen Lauri , Yang Tianyu , Yang Yang
Published: September 2022

We develop a linearized boundary control method for the inverse boundary value problem of determining a potential in the acoustic wave equation from the Neumann-to-Dirichlet map. When the linearization is at the zero potential, we derive a reconstruction formula based on the boundary control method and prove that it is of Lipschitz-type stability. When the linearization is at a nonzero potential, we prove that the problem is of Hölder-type stability in two and higher dimensions. The proposed reconstruction formula is implemented and evaluated using several numerical experiments to validate its feasibility.
Stable determination of coefficients in semilinear parabolic system with dynamic boundary conditions
Authors: Ait Ben Hassi El Mustapha , Chorfi Salah-Eddine , Maniar Lahcen
Published: September 2022

In this work, we study the stable determination of four space-dependent coefficients appearing in a coupled semilinear parabolic system with variable diffusion matrices subject to dynamic boundary conditions which couple intern-boundary phenomena. We prove a Lipschitz stability result for interior and boundary potentials by means of only one observation component, localized in any arbitrary open subset of the physical domain. The proof mainly relies on some new Carleman estimates for dynamic boundary conditions of surface diffusion type.
Field emitter electrostatics: a review with special emphasis on modern high-precision finite-element modelling
Authors: de Assis Thiago A , Dall’Agnol Fernando F , Forbes Richard G
Published: September 2022

This review of the quantitative electrostatics of field emitters, covering analytical, numerical and ‘fitted formula’ approaches, is thought the first of its kind in the 100 years of the subject. The review relates chiefly to situations where emitters operate in an electronically ideal manner, and zero-current electrostatics is applicable. Terminology is carefully described and is ‘polarity independent’, so that the review applies to both field electron and field ion emitters. It also applies more generally to charged, pointed electron-conductors—which exhibit the ‘electrostatic lightning-rod effect’, but are poorly discussed in general electricity and magnetism literature. Modern electron-conductor electrostatics is an application of the chemical thermodynamics and statistical mechanics of electrons. In related theory, the primary role of classical electrostatic potentials (rather than fields) becomes apparent. Space and time limitations have meant that the review cannot be comprehensive in both detail and scope. Rather, it focuses chiefly on the electrostatics of two common basic emitter forms: the needle-shaped emitters used in traditional projection technologies; and the post-shaped emitters often used in modelling large-area multi-emitter electron sources. In the post-on-plane context, we consider in detail both the electrostatics of the single post and the interaction between two identical posts that occurs as a result of electrostatic depolarization (often called ‘screening’ or ‘shielding’). Core to the review are discussions of the ‘minimum domain dimensions’ method for implementing effective finite-element-method electrostatic simulations, and of the variant of this that leads to very precise estimates of dimensionless field enhancement factors (error typically less than 0.001% in simple situations where analytical comparisons exist). Brief outline discussions, and some core references, are given for each of many ‘related considerations’ that are relevant to the electrostatic situations, methods and results described. Many areas of field emitter electrostatics are suggested where further research and/or separate mini-reviews would probably be useful.
Low-temperature infrared spectroscopy of the strongly correlated semiconductor Tm0.19Yb0.81B12with dynamic charge stripes
Authors: Zhukova Elena , Melentyev Aleksander , Gorshunov Boris , Muratov Andrey , Aleshchenko Yurii , Azarevich Andrey , Krasikov Kirill , Shitsevalova Natalya , Filipov Volodymyr , Sluchanko Nikolay
Published: September 2022

Tm1–xYbxB12dodecaborides represent model objects for the studies of quantum critical behavior, metal–insulator transitions (MITs) and complex charge-spin–orbital–phonon coupling phenomena. In spite of intensive investigations, the mechanism of semiconducting ground state formation both in YbB12and in the Yb-based strongly correlated electron systems remains a subject of active debates. We have performed first systematic measurements of temperature-dependent spectra of infrared conductivity of Tm0.19Yb81B12at frequencies 40–35 000 cm−1and in the temperature range 10–300 K. Analysis of the temperature evolution of the observed absorption resonances is performed allowing to associate these with the cooperative dynamic Jahn–Teller instability of the boron sub-lattice. This ferrodistortive effect of B12-complexes induces the rattling modes of the rare earth ions leading to emergence of both the intra-gap mixed-type collective excitations and the dynamic charge stripes. We estimate the temperature-dependent effective mass of charge carriers and propose the scenario of transformation of the many-body states in the multiple relaxation channels. We attribute the MIT to the localization of electrons at the vibrationally coupled Yb–Yb pairs, which is accompanied by the electronic phase separation and formation of the nanoscale filamentary structure of electron density (stripes) in Tm1–xYbxB12compounds.
Spin-selective thermoelectric transport along a vibrating α-helical protein molecule
Authors: Zhai Guangwei , Zhu Yanyan , Jiang Feng , Yan Yonghong , Wang Shikuan
Published: September 2022

Motivated by the development of bio-thermoelectricity and spin caloritronics, we studied the nonlinear spin-selective transport along a vibrating α-helical protein molecule in the presence of thermal bias by using the standard nonequilibrium Green’s function formalism. Our results demonstrate that the thermal bias induces the oscillation of spin-polarization between positive and negative values accompanied by spin current with increasing the chain length. Moreover, even for the very short preparable peptide chains, external electron-phonon interaction can give rise to the spin-selectivity, whereas characteristic electron-phonon interaction can not, but in conjunction with thermal bias, it has an important impact on the total current’s direction and the spin-polarized current intensity. Finally, the spin-polarization induced by thermal bias can be modulated by gate-bias much more easily as compared to that induced by electric bias. We conclude that by applying thermal bias and gate-bias, α-helical protein molecules are conducive to the storage of binary digits.
SWT-KELM-based rolling bearing fault diagnosis method under noise conditions with different SNRs
Authors: Wang Jinxi , Ye Chenglong , Jiang Mingshun , Zhang Faye , Sui Qingmei
Published: September 2022

Most existing studies carry out bearing fault diagnosis tasks in labs with weak noise. However, field noise is so heavy under actual conditions that some methods may suffer from degradation or failure. To solve this problem, a fault diagnosis framework is proposed based on the synchrosqueezing wavelet transform and kernel extreme learning machine (SWT-KELM). First, vibration signals are collected, and white Gaussian noise is added. Second, SWT is employed for signal decomposition in the time–frequency domain, and inverse SWT is applied for subsignal reconstruction. Subsignals with high correlation coefficients are selected for further feature extraction, specifically by singular value decomposition, to obtain singular values as the fault feature. Third, the KELM model, in which the beetle antennae search algorithm is employed for parameter optimization, is constructed to classify the faults. For verification, the proposed method is implemented on the Case Western Reserve University dataset and Lab-625 dataset, and the results show that it maintains satisfactory outcomes on original and noise-contaminated data. Specifically, under noisy conditions, the accuracies of the two datasets average at 96% and 83%, respectively, indicating the robustness and generalization of the method compared to other methods.