bluuebunny/crossref_metadata_2025 huggingface dataset:
Overexpansion-dominated coronal mass ejection formation and induced radio bursts
Authors: Wang B. T. , Cheng X. , Song H. Q. , Ding M. D.
Published: September 2022

Aims. Coronal mass ejections (CMEs) are the most fascinating explosions in the Solar System. Their formation is still not fully understood, however.

Methods. We investigated a well-observed CME on 2021 May 7 that showed a typical three-component structure and was continuously observed from 0 to 3 R⊙ by a combination of SDO/AIA (0–1.3 R⊙), PROBA2/SWAP (0–1.7 R⊙), and MLSO/K-Cor (1.05–3 R⊙). Furthermore, we compared the morphological discrepancy between the CME white-light bright core and the extreme-UV (EUV) blob. We finally explored the origin of various radio bursts that are closely related to the interaction of the CME overexpansion with a nearby streamer.

Results. An interesting finding is that the height increases of the CME leading front and of the bright core are dominated by the overexpansion during the CME formation. The aspect ratios of the CME bubble and bright core, quantifying the overexpansion, are found to decrease as the SO/STIX 4–10 keV and GOES 1–8 Å soft X-ray flux of the associated flare increases near the peaks. This indicates that the flare reconnection plays an important role in the first overexpansion. The CME bubble even undergoes a second overexpansion, although it is relatively weak, which is closely related to the compression with a nearby streamer and likely arises from an ideal magnetohydrodynamics process. Moreover, the CME EUV blob is found to be relatively lower and wider than the CME white-light bright core, which may correspond to the bottom part of the growing CME flux rope. The interaction between the CME and the streamer leads to two type II radio bursts, one that is drifting normally and another that is stationary, which are speculated to be induced by two different sources of the CME-driven shock front. The bidirectional electrons shown in series of C-shaped type III bursts suggest that the interchange reconnection is also involved during the interaction of the CME and streamer.
A census of OBe stars in nearby metal-poor dwarf galaxies reveals a high fraction of extreme rotators
Authors: Schootemeijer A. , Lennon D. J. , Garcia M. , Langer N. , Hastings B. , Schürmann C.
Published: September 2022

The early Universe, together with many nearby dwarf galaxies, is deficient in heavy elements. The evolution of massive stars in such environments is thought to be affected by rotation. Extreme rotators among them tend to form decretion disks and manifest themselves as OBe stars. We use a combination of UB, Gaia, Spitzer, and Hubble Space Telescope photometry to identify the complete populations of massive OBe stars – from one hundred to thousands in number – in five nearby dwarf galaxies. This allows us to derive the galaxy-wide fraction of main sequence stars that are OBe stars (fOBe), and how it depends on absolute magnitude, mass, and metallicity (Z). We find fOBe = 0.22 in the Large Magellanic Cloud (0.5 Z⊙), increasing to fOBe = 0.31 in the Small Magellanic Cloud (0.2 Z⊙). In the thus-far unexplored metallicity regime below 0.2 Z⊙, in Holmberg I, Holmberg II, and Sextans A, we also obtain high OBe star fractions of 0.27, 0.27, and 0.27, respectively. These high OBe star fractions and the strong contribution in the stellar mass range – which dominates the production of supernovae–, shed new light on the formation channel of OBe stars, as well as on the tendency for long-duration gamma-ray bursts and superluminous supernovae to occur in metal-poor galaxies.
Communication tool in management accounting: adapting Jakobson’s (1960) communication model
Authors: Huang Ying Sophie , Nemoto Moeki
Published: September 2022

Cognition is often a problem in management accounting communication. A gap arises between the sender and receiver of management accounting information, leading to miscommunication. A semiotic approach is a practical tool to decrease such miscommunication in management accounting. Jakobson’s communication model helps decrease such miscommunication. This study examines how Jakobson’s communication model is helpful for management accounting communication and our proposed communication model is intended to support management by providing relevant and timely information for planning, controlling, and decision-making. Additionally, our communication model is designed to decrease miscommunication.
Viscosity of concentrated superfluid mixtures 3He−4He when vibrating a quartz tuning fork
Authors: Chagovets V. K. , Kapuza S. S. , Sokolov S. S. , Vrakina V. A. , Chagovets T. V.
Published: September 2022

The possibility has been investigated for measuring the viscosity of concentrated superfluid mixtures of 3He in 4He in the temperature range 0.4−2.2 K using commercial quartz tuning forks with a resonance frequency of ≈ 32 kHz. It was found that the temperature dependence of the viscosity coefficient in a mixture with a concentration of 5% of 3He in 4He is in good qualitative agreement with the data obtained using other experimental techniques in the entire temperature range of the research. The same dependence of a mixture with 3He concentration of 15% agrees with the previously obtained data only at temperature T > 1.4 K, and at lower temperatures a difference appears that grows with decreasing temperature. The experimental temperature dependences of the viscosity coefficient obtained by different methods are compared with those calculated within the framework of the kinetic theory for the quasiparticles in superfluid 3He−4He solutions, developed by Landau, Khalatnikov, and Zharkov for the temperature range T > 0.6 K and by Baym, Saam, and Ebner for lower temperature.
Lattice mismatch induced tunable dimensionality of transition metal Di-chalcogenides
Authors: Dong Hanxiao , Jiang Huijun , Hou Zhonghuai
Published: September 2022

Low-dimensional materials have excellent properties which are closely related to their dimensionality. However, the growth mechanism underlying tunable dimensionality from 2D triangles to ID ribbons of such materials is still unrevealed. Here, we establish a general kinetic Monte Carlo model for transition metal dichalcogenides (TMDs) growth to address such an issue. Our model is able to reproduce several key ñndings in experiments, and reveals that the dimensionality is determined by the lattice mismatch and the interaction strength between TMDs and the substrate. We predict that the dimensionality can be well tuned by the interaction strength and the geometry of the substrate. Our work deepens the understanding of tunable dimensionality of low-dimensional materials and may inspire new concepts for the design of such materials with expected dimensionality.
Tomographic reconstruction techniques optimized for velocity-map imaging applications
Authors: Sparling Chris , Townsend Dave
Published: September 2022

Examples of extracting meaningful information from image projection data using tomographic reconstruction techniques can be found in many areas of science. Within the photochemical dynamics community, tomography allows for complete three-dimensional (3D) charged particle momentum distributions to be reconstructed following a photodissociation or photoionization event. This permits highly differential velocity- and angle-resolved measurements to be made simultaneously. However, the generalized tomographic reconstruction strategies typically adopted for use with photochemical imaging—based around the Fourier-slice theorem and filtered back-projection algorithms—are not optimized for these specific types of problems. Here, we discuss pre-existing alternative strategies—namely, the simultaneous iterative reconstruction technique and Hankel Transform Reconstruction (HTR)—and introduce them in the context of velocity-map imaging applications. We demonstrate the clear advantages they afford, and how they can perform considerably better than approaches commonly adopted at present. Most notably, with HTR we can set a bound on the minimum number of projections required to reliably reconstruct 3D photoproduct distributions. This bound is significantly lower than what is currently accepted and will help make tomographic imaging far more accessible and efficient for many experimentalists working in the field of photochemical dynamics.
Acid form of Trofimenko’s scorpionates, H(TpR,R′); comments on synthesis and solid-state structure of H(TptBu,Me)
Authors: Saliu Kuburat O. , Chen Jianhua , McDonald Robert , Takats Josef
Published: September 2022

We report a re-examination of Trofimenko’s original protocol for the preparation of the acid form of his hydrotris(pyrazolyl)borates, H(TpR,R′), by the treatment of M(TpR,R′)with glacial acetic acid. It is concluded that the protocol is effective as long as the 3-substituent of the pyrazolyl moiety is sufficiently bulky to provide steric protection to the acidic N–H proton. The solid-state structure of H(TptBu,Me), the acid form of the popular TptBu,Me ligand is also presented.
Corrigendum to: Morphological and molecular evidence refute a broad circumscription for Pultenaea glabra (Fabaceae: Mirbelieae), with implications for taxonomy, biogeography, and conservation
Authors: Renner Matthew A. M. , Barrett Russell L. , Clarke Steve , Clugston James A. R. , Wilson Trevor C. , Weston Peter H.
Published: September 2022

Morphological and single-nucleotide polymorphism data support splitting Pultenaea glabra Benth. into eight species, including one in Victoria, and seven in eastern and northern New South Wales. Six species are newly described, five of which are, like P. glabra, narrow-range endemics within the Greater Blue Mountains World Heritage Area and adjacent sandstone landforms of the Great Dividing Range. The recognition of six new species from what was broadly P. glabra has implications for conservation management, including for P. glabra itself, which has a smaller distribution and more precise habitat requirements than previously thought. One of the new species, P. percussa, is known by a single 1971 gathering only. The occurrence of several narrow-range Blue Mountains endemic Pultenaea species may be explained by the combination of edaphic diversity and topographic complexity, which could act in concert to promote divergences among small, allopatric populations. Hybrids between P. glabra and P. flexilis Sm. are documented for the first time; however, limited evidence for introgression between the two species was observed. The following new taxa are described: Pultenaea aculeata M.A.M.Renner, P.H.Weston & S.Clarke, Pultenaea percussa M.A.M.Renner & P.H.Weston, Pultenaea furcata M.A.M.Renner & R.L.Barrett, Pultenaea mutabilis M.A.M.Renner & P.H.Weston, Pultenaea mutabilis var. angusta M.A.M.Renner, P.H.Weston, & S.Clarke, Pultenaea praecipua M.A.M.Renner & P.H.Weston, Pultenaea praecipua subsp. temperata M.A.M.Renner & R.L.Barrett, and Pultenaea tenebrosa M.A.M.Renner, P.H.Weston & S.Clarke. Lectotypes are designated for Pultenaea villosa var. glabrescens Benth. and Pultenaea weindorferi Reader.
Corrigendum to: Three new tribes in Myrtaceae and reassessment of Kanieae
Authors: Wilson Peter G. , Heslewood Margaret M. , Tarran Myall A.
Published: September 2022

The current tribal classification of Myrtaceae was based on analysis of the plastid matK coding region within the trnK intron. The phylogenetic position of the genera Cloezia and Xanthomyrtus was poorly supported, and the original sequence for Kania, the type genus of the tribe Kanieae, was rather poor. To clarify relationships, we sequenced plastid psbA–trnH and an extended portion of the trnK intron, including the spacer regions flanking matK, and nuclear ribosomal ITS and ETS regions for representative species across the tribes, including denser sampling of the three genera of interest. Analyses of these extended datasets show a strong relationship between Kania and the tribe Metrosidereae but not with other genera presently assigned to the Kanieae. The relationship between Kania and the tribe Metrosidereae is strongly correlated with morphological features recently documented in Metrosideros fossils. Consequently, a new tribe, Tristaniopsideae PeterG.Wilson, is described to accommodate most genera presently assigned to Kanieae. Furthermore, the morphological divergence and genetic distance shown by Cloezia and Xanthomyrtus are here considered as justifying their recognition as the tribes Cloezieae Peter G.Wilson and Xanthomyrteae Peter G.Wilson. Recognition of these tribes brings to four the number of tribes absent from present-day mainland Australia. Prior to this study, Metrosidereae was the only tribe in subfamily Myrtoideae that was absent from mainland Australia.
Challenges and possible solutions to creating an achievable and effective Post-2020 Global Biodiversity Framework
Authors: Hughes Alice , Shen Xiaoli , Corlett Richard , Li Lin , Luo Maofang , Woodley Stephen , Zhang Yuanming , Ma Keping
Published: September 2022

Global biodiversity is in crisis as a result of human activity. This biodiversity crisis has been well documented by scientists, recognized by world leaders, politicians, businesses, and citizens. Both the biodiversity and climate crises need to be addressed now. 2020 was when this change was supposed to start, with the 15th Conference of Parties (COP15) of the Convention on Biodiversity (CBD) meeting in Kunming, and the 26th Conference of Parties (COP26) of the UN Framework Convention on Climate Change meeting in Glasgow, but both meetings were postponed. COP26 was held a year late (November 2021), while COP15 was split into two, with the first part held in Kunming in October 2021, and the second part scheduled for Montreal in December 2022. This meeting in Montreal – arguably the most important in the CBDs history – must agree on the Post-2020 Global Biodiversity Framework (GBF), to reverse biodiversity loss. Failure to reach agreement in Montreal would ultimately be a failure of us all, with irreversible consequences for life on earth. Yet, with three months before the final deadline only 20% of text and two targets are agreed. This paper reviews the factors hindering progress on the agreement and suggests possible solutions.
A robust RGB-D SLAM based on multiple geometric features and semantic segmentation in dynamic environments
Authors: Kuang Benfa , Yuan Jie , Liu Qiang
Published: September 2022

In indoor dynamic scenes, traditional visual simultaneous localization and mapping (SLAM) algorithms based on RGB-D cameras incorrectly use dynamic features to estimate the poses of the cameras, and do not fully utilize the geometric information in the scenes, resulting in the low positioning accuracy and robustness of SLAM systems. To solve this problem, this paper proposes an RGB-D SLAM algorithm based on multiple geometric features and semantic segmentation. The core of our SLAM system is the proposed robust exclusion method of dynamic point and line features. The method consists of the following three steps: (a) identify potential dynamic point features using motion consistency checks; (b) obtain potential motion regions via semantic segmentation, and then determine dynamic regions by combining these with dynamic point features; (c) remove point and line features in dynamic regions. The exclusion method of dynamic point and line features can be easily integrated into RGB-D SLAM systems for improving the accuracy and robustness of SLAM systems in dynamic scenes. Experimental results on the Technische Universität München (TUM) dataset demonstrate that the proposed algorithm has better positioning accuracy and stability than the original dynamic semantic (DS-SLAM) algorithm in dynamic environments. The effectiveness of the proposed algorithm is verified by comparison with other classical visual SLAM algorithms. Better mapping performance is achieved by this proposed algorithm in actual indoor scenes.
Development of sound reflection and refraction experiment equipment
Authors: Kang Eunju , Park Jongho
Published: September 2022

The reflection and refraction of light are more familiar to students than the reflection and refraction of sound. Reflection and refraction that occur during the transmission of sound waves are common phenomena in everyday life but are often difficult to understand during actual learning. In this study, we developed a sound reflection and refraction test apparatus that can measure sound’s reflection and refraction angles by injecting sound using a super directional speaker with excellent straightness. Consequently, moving the sound sensor made it possible to find a point with high sound pressure and measure the sound’s reflection and refraction angles. Since this device is similar to the experimental device that measures the angle of reflection and refraction of light, it is expected to be able to phenomenologically compare and confirm the reflection and refraction paths of light and sound.
Imaging of polychromatic sources through Compton spectral reconstruction
Authors: Muñoz Enrique , Etxebeste Ane , Dauvergne Denis , Létang Jean Michel , Sarrut David , Maxim Voichita , Testa Etienne
Published: September 2022

Objective. Study the performance of a spectral reconstruction method for Compton imaging of polychromatic sources and compare it to standard Compton reconstruction based on the selection of photopeak events. Approach. The proposed spectral and the standard photopeak reconstruction methods are used to reconstruct images from simulated sources emitting simultaneously photons of 140, 245, 364 and 511 keV. Data are simulated with perfect and realistic energy resolutions and including Doppler broadening. We compare photopeak and spectral reconstructed images both qualitatively and quantitatively by means of activity recovery coefficient and spatial resolution. Main results. The presented method allows improving the images of polychromatic sources with respect to standard reconstruction methods. The main reasons for this improvement are the increase of available statistics and the reduction of contamination from higher initial photon energies. The reconstructed images present lower noise, higher activity recovery coefficient and better spatial resolution. The improvements become more sensible as the energy resolution of the detectors decreases. Significance. Compton cameras have been studied for their capability of imaging polychromatic sources, thus allowing simultaneous imaging of multiple radiotracers. In such scenarios, Compton images are conventionally reconstructed for each emission energy independently, selecting only those measured events depositing a total energy within a fixed window around the known emission lines. We propose to employ a spectral image reconstruction method for polychromatic sources, which allows increasing the available statistics by using the information from events with partial energy deposition. The detector energy resolution influences the energy window used to select photopeak events and therefore the level of contamination by higher energies. The spectral method is expected to have a more important impact as the detector resolution worsens. In this paper we focus on energy ranges from nuclear medical imaging and we consider realistic energy resolutions.
Unsupervised contrastive learning based transformer for lung nodule detection
Authors: Niu Chuang , Wang Ge
Published: September 2022

Objective. Early detection of lung nodules with computed tomography (CT) is critical for the longer survival of lung cancer patients and better quality of life. Computer-aided detection/diagnosis (CAD) is proven valuable as a second or concurrent reader in this context. However, accurate detection of lung nodules remains a challenge for such CAD systems and even radiologists due to not only the variability in size, location, and appearance of lung nodules but also the complexity of lung structures. This leads to a high false-positive rate with CAD, compromising its clinical efficacy. Approach. Motivated by recent computer vision techniques, here we present a self-supervised region-based 3D transformer model to identify lung nodules among a set of candidate regions. Specifically, a 3D vision transformer is developed that divides a CT volume into a sequence of non-overlap cubes, extracts embedding features from each cube with an embedding layer, and analyzes all embedding features with a self-attention mechanism for the prediction. To effectively train the transformer model on a relatively small dataset, the region-based contrastive learning method is used to boost the performance by pre-training the 3D transformer with public CT images. Results. Our experiments show that the proposed method can significantly improve the performance of lung nodule screening in comparison with the commonly used 3D convolutional neural networks. Significance. This study demonstrates a promising direction to improve the performance of current CAD systems for lung nodule detection.
Hidden Markov model in nonnegative matrix factorization for fetal heart rate estimation using physiological priors
Authors: Reséndiz Rojas Mariel , Fontecave-Jallon Julie , Rivet Bertrand
Published: September 2022

Objective. Fetal heart rate (fHR) analysis remains the most common technique for detecting fetal distress when monitoring the fetal well-being during labor. If cardiotocography (CTG) is nowadays the non-invasive clinical reference technique for fHR measurement, it suffers from several drawbacks, hence an increasing interest towards alternative technologies, especially around abdominal ECG (aECG). Approach. An original solution, using a single abdominal lead, was recently proposed to address both the feasibility in clinical routine and the challenging detection of temporal events when facing interfered signals from real life conditions. Based on a specification of the non-negative matrix factorization (NMF) algorithm, it exploits the semi-periodicity of fetal electrocardiogram (fECG) for fHR estimation. However, this method assumes temporal independence and therefore does not consider the continuity property of fHR values. It is thus proposed to add to the NMF framework a hidden Markov model (HMM) to include physiological information about fHR temporal evolution. Under a statistical setting, constraints have been added by accommodating regularization terms through Bayesian priors. Main results. The proposed method is evaluated on 23 real aECG signals from a new clinical database, according to CTG reference, and compared with the original NMF-only algorithm. The new proposed method improves performance, with an agreement with CTG increasing from 71% to 80%. Significance. This highlights the interest of a better modelization of the fHR characteristics for a more robust estimation.
Frequency estimation under non-Markovian spatially correlated quantum noise
Authors: Riberi Francisco , Norris Leigh M , Beaudoin Félix , Viola Lorenza
Published: September 2022

We study the estimation precision attainable by entanglement-enhanced Ramsey interferometry in the presence of spatiotemporally correlated non-classical noise. Our analysis relies on an exact expression of the reduced density matrix of the qubit probes under general zero-mean Gaussian stationary dephasing, which is established through cumulant-expansion techniques and may be of independent interest in the context of non-Markovian open dynamics. By continuing and expanding our previous work (Beaudoin et al 2018 Phys. Rev. A 98 020102(R)), we analyze the effects of a non-collective coupling regime between the qubit probes and their environment, focusing on two limiting scenarios where the couplings may take only two or a continuum of possible values. In the paradigmatic case of spin–boson dephasing noise from a thermal environment, we find that it is in principle possible to suppress, on average, the effect of spatial correlations by randomizing the location of the probes, as long as enough configurations are sampled where noise correlations are negative. As a result, superclassical precision scaling is asymptotically restored for initial entangled states, including experimentally accessible one-axis spin-squeezed states.
A fuzzy purchase model with backorders - GMI method of defuzzification
Authors: Kasthuri R , Vasanthi P , Ranganayaki S , Kavithamani K
Published: September 2022

A fuzzy EOQ model with backorders is considered in which the costs like setup, holding and the penalty price are assumed as triangular FN (fuzzy numbers). Graded mean integration approach which is more simple and accurate is employed to defuzzify the cost functions. The model is illustrated with numerical examples to compute the optimal values.
Rendering Abstract Notation of Kinematic Chains to Modified Franke’s Notation Form
Authors: H Manikandan , Kaup Vijayananda , Babu Harish
Published: September 2022

To bring about innovation in the development of any product, it is required that the designer explores multitude design concepts right at the conceptual design phase of the product development cycle. At this phase, results of structural synthesis and analysis of mechanisms have been shown to serve as an invaluable tool in the attempt to infuse novelty in the design being conceptualized. There are several studies available in literature dealing with structural enumeration of kinematic chains. Invariably, all these studies culminate in reporting the results in an abstract form such as link adjacency matrix or its simpler variants like joints’ lists, etc. Certainly, it will be more useful to designers if the chain were reported in the pictorial form since it will be more intuitive for designers to fruitfully relate what is in his mind as an unformulated idea to what is directly visible as a sketch. This paper presents the results of a computer based method that converts link adjacency matrix into modified Franke’s notation format. The way to draw full-fledged chain from its modified Franke’s notation form is explained. Chains containing 8 or more links and possessing 1 to 5 freedoms have been sketched and made available in the form of a PDF file.
Research on the effects of raft on vibration isolation
Authors: Zhang Zhenli , Liu Haijian , Tan Haitao , Wang Qiangyong , Chao Shang , Yang Xuesong , Guo Hanbei
Published: September 2022

The floating raft vibration isolation system includes upper and lower isolators and middle raft. As one of the most important parts that affect the performance of vibration isolation, the raft is usually assumed to be an undamped or viscous damping structure in the analysis, which is different from the actual situation. To study the effects of raft with hysteresis damping characteristics, a three-freedom complex stiffness mechanical model was built, and an approach for calculating the raft's force transmission rate was derived from impedance methods. Based on the mechanical model and a large-sized floating raft, we analysed the effects of raft mass, stiffness and damping on vibration isolation through numerical calculation. Results show that increasing raft mass improved vibration isolation over most frequency ranges; increase in raft stiffness contributed to improved isolation performance over frequency ranges near its low-order natural frequencies, while reduced the performance over higher frequency ranges; and greater raft damping led to enhanced vibration isolation at its natural frequencies and higher frequency ranges.
Experimental study on the anti-penetration performance of 675 armor steel at low temperature
Authors: Chang Xuna , Han Feng , Ren Yunyan , Zhou Qiao , Liu Yang
Published: September 2022

675 armor steel is a kind of high strength and hard steel newly developed and put into use, which has excellent anti-penetration performance. In order to study the anti-penetration performance of 675 armor steel on 30CrMnSiNi2A projectile and analyze the influence of low temperature on the anti-penetration performance of 675 armor steel. By impacting 675 armor steel with a one-stage light-gas gun, the mechanism of action of the target and the mechanical behavior of armor steel were analyzed. On this basis, adjusted the experimental temperature of 675 armor steel. It was found that the 675 armor steel target plate crater and dorsal mutant are consistent with temperature changes in the range of -40 to 15 °C, increasing first and then decreasing with the increase of temperature, and the dorsal mutant is smaller than the deformation of the crater. None of the projectiles can form penetrating pores on the target plate and the projectile fragmentation occurs at the beginning of the target collision at 4 different temperatures. The projectile impact target plate has a slight damage crater on the front and a bulge on the back. The results of this paper can provide important reference value for the analysis of the role of the target and the study of the anti-penetration mechanism of 675 armor steel.
Impact of cryogenic treatment on the microstructure and properties of a thermo-mechanically processed Cu-11Fe composite
Authors: Liu Keming , Jin Ying , Fu Kai , Shi Jinke , Li Mulin , Wen Jiahao , Zhang Yanyan , Shen Zhi , Huang Zhikai
Published: September 2022

The conductivity and strength of Cu-Fe composites are contradictory. Cryogenic treatment is a promising process to improve the conductivity and strength of materials at the same time. The impact of cryogenic treatment on a thermo-mechanically processed Cu-11Fe composite was studied using a digital micro-ohmmeter, a tensile testing machine and optical microscopy. The average size of the iron grain in the cryogenically treating Cu-11Fe alloy decreased and the distribution was more uniform after the cryogenic treatment. The grain refinement and the distribution uniformity increased with improving cryogenic treatment time. The elongation to fracture and tensile strength improved first with increasing cryogenic treatment time to a peak value at 18 h and 12 h respectively, and subsequently tended to be stable at longer cryogenic treatment time. The electrical resistivity decreased first with the increase of cryogenic treatment time, then reached an electrical resistivity valley value at 18 h, and subsequently tended to be stable at longer cryogenic treatment time.
Study on high thermal conductivity insulation materials for wide temperature range applications
Authors: Huang Haichao , Zhao Dongyan , Chen Yanning , Fu Zhen , Wang Shuaipeng , Liu Fang
Published: September 2022

A new design method of highly reliable thermally conductive packaging material is proposed for the heat dissipation problem of high-density packaging of chips. The high reliability is obtained by high temperature condensation of AlN particles suspension of PAA. Focusing on the influence law of the content of AIN on the electronic packaging material, the experimental results show that the thermal conductivity reaches 3.8 W/(m⋅K) when the mass percentage of AIN reach more than 60%. The Td in N2 is 524°C. The surface of AIN is modified by the macromolecular coupling agent GBM to increase the compatibility of AIN with the Polymeric materials. The tensile strength of PI/AlN composite is 170 MPa, and the material has good insulation performance when the temperature rises to 200°C under 120 kV/mm electric field, which meets the application requirements of high-density chip packaging.
Study on Structural, Electrical and Magnetical Properties of Zn Doped CuAlO2 Ceramics
Authors: Liu Yantao , Wang Ying , Ma Jianping
Published: September 2022

To improve the properties of CuAlO2 thin films, the preparation of CuAlO2 ceramics with excellent properties is an important prerequisite, and the optimization of ceramic properties is often achieved by doping. Zn-doped CuAlO2 ceramics were prepared by the solid phase sintering method. The structural, electrical and magnetic properties of Zn-doped CuAlO2 ceramics were systematically studied. The results show that the crystal structure of the as-sintered Zn-doped CuAlO2 was rhombohedral, space group R3m. Grain size of samples grew with the amount of Zn increases, which is related to the enhancement of CuAl2O4 phases in the sample ceramics. The density of doped ceramics changed when increasing Zn-doping concentration compared to undoped ceramics. It reached a minimum 0.96 g/cm3. The resistivity of Zn-doped CuAlO2 ceramic samples climbed with the increase of Zn content, and it can reach 59.6 Ω•cm at 10 mol%. The ferromagnetic behavior was enhanced with increasing the Zn concentration.
Study on hydrophobic properties of coatings enhanced by organofluorosilicone polymers
Authors: Xiang Dingding , Liu Kanglian , Wu Dawang , Zhou Jing , Cao Maoqi , Mao Haili
Published: September 2022

Hydrophobic materials are widely used in industry and life. It is of great practical significance to develop new hydrophobic materials. In this paper, organofluorosilicone polymers were prepared by low-cost and easily accessible process using organofluorosilicone prepolymers as reactants and under the action of organosilicon crosslinking agent. Infrared spectrum test showed that the prepared organofluorosilicone polymer had obvious C-F stretching vibration peak at 1211cm-1, which proved the effective synthesis of organofluorosilicone polymer. The test of contact Angle under water condition shows that the water contact Angle of coating materials added with organofluorosilicone polymer is larger. Therefore, organofluorosilicone polymer can be used as a kind of efficient hydrophobic additive to enhance the hydrophobicity of coating materials.
The study on modulable tin whisker growth behaviors and mechanisms on Ti2SnC
Authors: Liu Yushuang , Zhang Peigen , Sun ZhengMing
Published: September 2022

The spontaneous growth of tin whiskers has resisted interpretation for more than 70 years. Herein, tin whisker growth behaviours on Ti2SnC bulks cold-pressed under different pressures were studied. It was found that higher whisker growth propensity is reached when Ti2SnC cold-pressed under higher pressure. Several thicker whiskers with diameter more than 3 μm were observed on the samples formed under higher pressure, while the diameter of more than 50% whiskers ranges from 0.5 μm to 1.5 μm for all of the samples. An atomic motion mechanism, in which the element source supplying Sn whisker growth diffuse through the Sn atom layer in Ti2SnC lattice, and the interaction between Ti2SnC and Sn is considered to be the fundamental factor initiating the Sn whisker growth, was employed to understand the phenomena. The findings herein provide new clues to understand the tin whisker growth behaviors and modulable metal whisker fabrication.
Legged locomotion over irregular terrains: state of the art of human and robot performance
Authors: Torres-Pardo Adriana , Pinto-Fernández David , Garabini Manolo , Angelini Franco , Rodriguez-Cianca David , Massardi Stefano , Tornero Jesús , Moreno Juan C , Torricelli Diego
Published: September 2022

Legged robotic technologies have moved out of the lab to operate in real environments, characterized by a wide variety of unpredictable irregularities and disturbances, all this in close proximity with humans. Demonstrating the ability of current robots to move robustly and reliably in these conditions is becoming essential to prove their safe operation. Here, we report an in-depth literature review aimed at verifying the existence of common or agreed protocols and metrics to test the performance of legged system in realistic environments. We primarily focused on three types of robotic technologies, i.e., hexapods, quadrupeds and bipeds. We also included a comprehensive overview on human locomotion studies, being it often considered the gold standard for performance, and one of the most important sources of bioinspiration for legged machines. We discovered that very few papers have rigorously studied robotic locomotion under irregular terrain conditions. On the contrary, numerous studies have addressed this problem on human gait, being nonetheless of highly heterogeneous nature in terms of experimental design. This lack of agreed methodology makes it challenging for the community to properly assess, compare and predict the performance of existing legged systems in real environments. On the one hand, this work provides a library of methods, metrics and experimental protocols, with a critical analysis on the limitations of the current approaches and future promising directions. On the other hand, it demonstrates the existence of an important lack of benchmarks in the literature, and the possibility of bridging different disciplines, e.g., the human and robotic, towards the definition of standardized procedures that will boost not only the scientific development of better bioinspired solutions, but also their market uptake.
Ergodicity of the Wang–Swendsen–Kotecký algorithm on several classes of lattices on the torus
Authors: Salas Jesús , Sokal Alan D
Published: September 2022

We prove the ergodicity of the Wang–Swendsen–Kotecký (WSK) algorithm for the zero-temperature q-state Potts antiferromagnet on several classes of lattices on the torus. In particular, the WSK algorithm is ergodic for q ⩾ 4 on any quadrangulation of the torus of girth

⩾
4

. It is also ergodic for q ⩾ 5 (resp. q ⩾ 3) on any Eulerian triangulation of the torus such that one sublattice consists of degree-4 vertices while the other two sublattices induce a quadrangulation of girth

⩾
4

(resp. a bipartite quadrangulation) of the torus. These classes include many lattices of interest in statistical mechanics.
Chemically exfoliated nanosheets of β-Bi2O3
Authors: Hoff Brianna L , Cheng Guangming , Villalpando Graciela , Yuan Fang , Yao Nan , Schoop Leslie M
Published: September 2022

Exploring two dimensional (2D) materials is important for further developing the field of quantum materials. However, progress in 2D material development is limited by difficulties with their production. Specifically, freestanding 2D materials with bulk non-layered structures remain particularly challenging to prepare. Traditionally, chemical or mechanical exfoliation is employed for obtaining freestanding 2D materials, but these methods typically require layered starting materials. Here we put forth a method for obtaining thin layers of β-Bi2O3, which has a three-dimensional covalent structure, by using chemical exfoliation. In this research, Na3Ni2BiO6 was exfoliated with acid and water to obtain β-Bi2O3 nanosheets less than 10 nm in height and over 1 µm in lateral size. Our results open the possibility for further exploring β-Bi2O3 nanosheets to determine whether their properties change from the bulk to the nanoscale. Furthermore, this research may facilitate further progress in obtaining nanosheets of non-layered bulk materials using chemical exfoliation.
Phylotranscriptomics reveal the spatio-temporal distribution and morphological evolution ofMacrozamia, an Australian endemic genus of Cycadales
Authors: Habib Sadaf , Gong Yiqing , Dong Shanshan , Lindstrom Anders , William Stevenson Dennis , Liu Yang , Wu Hong , Zhang Shouzhou
Published: September 2022

Background and Aims

Cycads are regarded as an ancient lineage of living seed plants, and hold important clues to understand the early evolutionary trends of seed plants. The molecular phylogeny and spatio-temporal diversification of one of the species-rich genera of cycads, Macrozamia, have not been well reconstructed.

Methods

We analysed a transcriptome dataset of 4740 single-copy nuclear genes (SCGs) of 39 Macrozamia species and two outgroup taxa. Based on concatenated (maximum parsimony, maximum likelihood) and multispecies coalescent analyses, we first establish a well-resolved phylogenetic tree of Macrozamia. To identify cyto-nuclear incongruence, the plastid protein coding genes (PCGs) from transcriptome data are extracted using the software HybPiper. Furthermore, we explore the biogeographical history of the genus and shed light on the pattern of floristic exchange between three distinct areas of Australia. Six key diagnostic characters are traced on the phylogenetic framework using two comparative methods, and infra-generic classification is investigated.

Key Results

The tree topologies of concatenated and multi-species coalescent analyses of SCGs are mostly congruent with a few conflicting nodes, while those from plastid PCGs show poorly supported relationships. The genus contains three major clades that correspond to their distinct distributional areas in Australia. The crown group of Macrozamia is estimated to around 11.80 Ma, with a major expansion in the last 5–6 Myr. Six morphological characters show homoplasy, and the traditional phenetic sectional division of the genus is inconsistent with this current phylogeny.

Conclusions

This first detailed phylogenetic investigation of Macrozamia demonstrates promising prospects of SCGs in resolving phylogenetic relationships within cycads. Our study suggests that Macrozamia, once widely distributed in Australia, underwent major extinctions because of fluctuating climatic conditions such as cooling and mesic biome disappearance in the past. The current close placement of morphologically distinct species in the phylogenetic tree may be related to neotenic events that occurred in the genus.
Seronegative autoimmune encephalitis: exploring the unknown
Authors: van Steenhoven Robin W , Titulaer Maarten J
Published: September 2022

This scientific commentary refers to ‘Seronegative autoimmune encephalitis: clinical characteristics and factors associated with outcomes’ by Lee et al. (https://doi.org/10.1093/brain/awac166).
Brain network dynamics codify heterogeneity in seizure evolution
Authors: Rungratsameetaweemana Nuttida , Lainscsek Claudia , Cash Sydney S , Garcia Javier O , Sejnowski Terrence J , Bansal Kanika
Published: September 2022

Dynamic functional brain connectivity facilitates adaptive cognition and behaviour. Abnormal alterations within such connectivity could result in disrupted functions observed across various neurological conditions. As one of the most common neurological disorders, epilepsy is defined by the seemingly random occurrence of spontaneous seizures. A central but unresolved question concerns the mechanisms by which extraordinarily diverse propagation dynamics of seizures emerge. Here, we applied a graph-theoretical approach to assess dynamic reconfigurations in the functional brain connectivity before, during and after seizures that display heterogeneous propagation patterns despite sharing similar cortical onsets. We computed time-varying functional brain connectivity networks from human intracranial recordings of 67 seizures (across 14 patients) that had a focal origin—49 of these focal seizures remained focal and 18 underwent a bilateral spread (focal to bilateral tonic-clonic seizures). We utilized functional connectivity networks estimated from interictal periods across patients as control. Our results characterize network features that quantify the underlying functional dynamics associated with the observed heterogeneity of seizure propagation across these two types of focal seizures. Decoding these network features demonstrate that bilateral propagation of seizure activity is an outcome of the imbalance of global integration and segregation in the brain prior to seizure onset. We show that there exist intrinsic network signatures preceding seizure onset that are associated with the extent to which an impending seizure will propagate throughout the brain (i.e. staying within one hemisphere versus spreading transcallosally). Additionally, these features characterize an increase in segregation and a decrease in excitability within the brain network (i.e. high modularity and low spectral radius). Importantly, seizure-type-specific differences in these features emerge several minutes prior to seizure onset, suggesting the potential utility of such measures in intervention strategies. Finally, our results reveal network characteristics after the onset that are unique to the propagation mechanisms of two most common focal seizure subtypes, indicative of distinct reconfiguration processes that may assist termination of each seizure type. Together, our findings provide insights into the relationship between the temporal evolution of seizure activity and the underlying functional connectivity dynamics. These results offer exciting avenues where graph-theoretical measures could potentially guide personalized clinical interventions for epilepsy and other neurological disorders in which extensive heterogeneity is observed across subtypes as well as across and within individual patients.
Vibration accelerates orthodontic tooth movement by inducing osteoclastogenesis via transforming growth factor-β signalling in osteocytes
Authors: Sasaki Kiyo , Takeshita Nobuo , Fukunaga Tomohiro , Seiryu Masahiro , Sakamoto Mayuri , Oyanagi Toshihito , Maeda Toshihiro , Takano-Yamamoto Teruko
Published: September 2022

Background

We previously found the conditions of supplementary vibration that accelerated tooth movement and induced bone resorption in an experimental rat tooth movement model. However, the molecular biological mechanisms underlying supplementary vibration-induced orthodontic tooth movement are not fully understood. Transforming growth factor (TGF)-β upregulates osteoclastogenesis via induction of the receptor activator of nuclear factor kappa B ligand expression, thus TGF-β is considered an essential cytokine to induce bone resorption.

Objectives

The aim of this study is to examine the role of TGF-β during the acceleration of orthodontic tooth movement by supplementary vibration.

Materials and methods

In experimental tooth movement, 15 g of orthodontic force was loaded onto the maxillary right first molar for 28 days. Supplementary vibration (3 g, 70 Hz) was applied to the maxillary first molar for 3 min on days 0, 7, 14, and 21. TGF-β receptor inhibitor SB431542 was injected into the submucosal palatal and buccal areas of the maxillary first molars once every other day. The co-culture of RAW264.7 cells and MLO-Y4 cells was used as an in vitro osteoclastogenesis model.

Results

SB431542 suppressed the acceleration of tooth movement and the increase in the number of osteoclasts by supplementary vibration in our experimental rat tooth movement model. Immunohistochemical analysis showed supplementary vibration increased the number of TGF-β1-positive osteocytes in the alveolar bone on the compression side during the experimental tooth movement. Moreover, vibration-upregulated TGF-β1 in MLO-Y4 cells induced osteoclastogenesis.

Conclusions

Orthodontic tooth movement was accelerated by supplementary vibration through the promotion of the production of TGF-β1 in osteocytes and subsequent osteoclastogenesis.
Searching for a Consensus Among Inflammatory Bowel Disease Studies: A Systematic Meta-Analysis
Authors: Abdel-Rahman Lama Izzat Hasan , Morgan Xochitl C
Published: September 2022

Background

Numerous studies have examined the gut microbial ecology of patients with Crohn’s disease (CD) and ulcerative colitis, but inflammatory bowel disease–associated taxa and ecological effect sizes are not consistent between studies.

Methods

We systematically searched PubMed and Google Scholar and performed a meta-analysis of 13 studies to analyze how variables such as sample type (stool, biopsy, and lavage) affect results in inflammatory bowel disease gut microbiome studies, using uniform bioinformatic methods for all primary data.

Results

Reduced alpha diversity was a consistent feature of both CD and ulcerative colitis but was more pronounced in CD. Disease contributed significantly variation in beta diversity in most studies, but effect size varied, and the effect of sample type was greater than the effect of disease. Fusobacterium was the genus most consistently associated with CD, but disease-associated genera were mostly inconsistent between studies. Stool studies had lower heterogeneity than biopsy studies, especially for CD.

Conclusions

Our results indicate that sample type variation is an important contributor to study variability that should be carefully considered during study design, and stool is likely superior to biopsy for CD studies due to its lower heterogeneity.