bluuebunny/crossref_metadata_2025_split huggingface dataset:
A freeze-and-thaw-induced fragment of the microtubule-associated protein tau in rat brain extracts: implications for the biochemical assessment of neurotoxicity
Authors: Vasconcelos Israel C. , Campos Raquel M. , Schwaemmle Hanna K. , Masson Ana P. , Ferrari Gustavo D. , Alberici Luciane C. , Faça Vitor M. , Garcia-Cairasco Norberto , Sebollela Adriano 
Published: February 2021

Abstract
Tau is a microtubule-associated protein (MAP) responsible for controlling the stabilization of microtubules in neurons. Tau function is regulated by phosphorylation. However, in some neurological diseases Tau becomes aberrantly hyperphosphorylated, which contributes to the pathogenesis of neurological diseases, known as tauopathies. Western blotting (WB) has been widely employed to determine Tau levels in neurological disease models. However, Tau quantification by WB should be interpreted with care, as this approach has been recognized as prone to produce artifactual results if not properly performed. In the present study, our goal was to evaluate the influence of a freeze-and-thaw cycle, a common procedure preceding WB, to the integrity of Tau in brain homogenates from rats, 3xTg-AD mice and human samples. Homogenates were prepared in ice-cold RIPA buffer supplemented with protease/phosphatase inhibitors. Immediately after centrifugation, an aliquot of the extracts was analyzed via WB to quantify total and phosphorylated Tau levels. The remaining aliquots of the same extracts were stored for at least 2 weeks at either −20 or −80°C and then subjected to WB. Extracts from rodent brains submitted to freeze-and-thaw presented a ∼25 kDa fragment immunoreactive to anti-Tau antibodies. An in-gel digestion followed by mass spectrometry (MS) analysis in excised bands revealed this ∼25 kDa species corresponds to a Tau fragment. Freeze-and-thaw-induced Tau proteolysis was detected even when extracts were stored at −80°C. This phenomenon was not observed in human samples at any storage condition tested. Based on these findings, we strongly recommend the use of fresh extracts of brain samples in molecular analysis of Tau levels in rodents.
Review on DC transmission systems for integrating large‐scale offshore wind farms
Authors: Li Zhengxuan , Song Qiang , An Feng , Zhao Biao , Yu Zhanqing , Zeng Rong 
Published: February 2021

AbstractThe exploitation of offshore wind power has increased rapidly in recent years. To gain more wind power energy, offshore wind farms move farther from onshore. A comparison between HVAC and HVDC in terms of reliability, cost and transmission capability shows that HVDC is more suitable for long‐distance, high‐capacity bulk power transmission. However, the HVDC transmission for offshore wind power also faces great challenges because the offshore applications bring critical demands for low volume and low weight for the converters at the offshore side. On the other hand, the new topologies and conversion techniques of power electronic converters expedite many new DC transmission architectures for offshore wind power. Different HVDC architectures by using centralised voltage source converter (VSC), diode rectifier (DR), series‐connected wind turbine converters and all‐DC wind farm based on DC transformers are reviewed and compared. The advantages, challenges and development and application prospects for various DC transmission solutions are discussed.
Intriguing detection of 12CO molecular emission in a classical Be star
Authors: Cochetti Y. R. , Arias M. L. , Kraus M. , Cidale L. S. , Torres A. F. , Granada A. , Maryeva O. V. 
Published: February 2021

Context. In the group of B stars with spectroscopic peculiarities, we can find the Be and the B[e] stars. The Be stars are early-type rapid rotators that present, as their principal characteristic, emission lines of hydrogen and singly ionized metals due to the presence of a gaseous envelope. The B[e] stars present in their spectra heterogeneous features that reveal the presence of regions with very different properties in a gaseous and dusty envelope.
Aims. Our goal is to study the evolution of the disks around peculiar B stars through the variability of their physical properties and dynamical structure, as well as to set constraints on different models and disk forming mechanisms.
Methods. Throughout the last decade, we have carried out temporal monitoring of a sample of objects in the near infrared using spectroscopic facilities at the Gemini and Las Campanas Observatories. In the present work, we focus on the classical Be star 12 Vul, for which also optical spectra have been collected quasi-simultaneously.
Results. We observed variability in the hydrogen line profiles of 12 Vul, attributed to dissipating and building-up processes of the circumstellar envelope. Also, we found that this Be star presented the 12CO band heads in emission in one observation. The emission of this molecule has not been previously reported in a Be star, while it is a common feature among B[e] stars. We obtained parameters to describe the 12CO emitting region and propose different scenarios to explain this intriguing emission.
The limits of institutionalizing predominance: understanding the emergence of Turkey’s new opposition
Authors: Aras Bülent , Helms Ludger 
Published: February 2021

AbstractThis article offers an institutionalist assessment of the more recent chapters of political opposition in Erdoğan’s Turkey. There is good reason to suppose that the institutional features of a given regime can explain the performance of opposition parties to a significant extent. That said, the case of Turkey provides impressive evidence that there are striking limits to institutionalizing political predominance, to undermining political oppositions by institutional means, and to explaining the performance of opposition parties with the prevailing institutional resources and constraints. Specifically, attempts at institutionalizing a predominant power status carry particular risks of generating inverse effects, including increased political vulnerability. However, there are no automatic effects. Rather, as the Turkish experience suggests, reasonably vigorous actors to become politically relevant must seize the particular (if usually limited) opportunities arising from advanced institutional autocratization.
Translating additive connectors from English into Spanish and vice versa
Authors: Labrador Belén 
Published: February 2021

AbstractThis contrastive study aims to analyze and compare the usages of one type of sentence connectors, reinforcing additive connectors, in English and in Spanish through a corpus-based approach, which relies on bidirectional translation data. The analysis includes behavioral profiles of each of the list of connectors in each language, comparisons among them, comparisons between original texts and translated texts in both directions, cross-register differences, translational options, and the connectors’ mutual correspondence, which shows the degree of equivalence of each pair of connectors based on how often they are translated into each other. The results show important differences in the use of reinforcing additive connectors, mainly connected with (a) the more even distribution in English as compared with the great predominance of one connector in Spanish,además; (b) a more marked tendency for explicitation in Spanish and for the use of zero translation in English; (c) generally low mutual correspondence values, which seem to reflect high language variation, richness, and complex mapping of resources utilized to connect sentences.
A wireless passive pressure sensor using microstructured ferromagnetic films with tunable effective permeability
Authors: Lin Y-C , Cai M-X , Yang Y-J 
Published: February 2021

Abstract
This paper presents a novel LC-based passive wireless flexible pressure sensor that employs microstructured ferromagnetic films with tunable effective permeability. The proposed device consists of a micromachined planar spiral coil and a polymer film with cilia arrays (CAs) realized by the ferrofluidic instability principle. The effective permeability of the polymer film can be tuned by deforming the CAs with externally applied pressure, which can be estimated in turn by detecting the resonant frequency of the device using the phase-dip technique. The fabrication parameters for synthesizing different dimensions and densities of CAs were investigated as well. Devices of different CA densities were measured and discussed. The measured results showed that the device quality factor and phase change both increased with applied pressure. Due to this characteristic, the proposed device is advantageous over typical capacitive LC-based devices and performs better in wireless interrogation while maintaining the sensitivity of pressure sensing.
Tunable plasmonic resonator using conductivity modulated Bragg reflectors
Authors: Pathiranage Sachinthana , Gunapala Sarath D , Premaratne Malin 
Published: February 2021

Abstract
We design a tunable plasmonic resonator that may have applications in sensing and plasmon generation—our design uses graphene-based Bragg reflectors of periodically modulated conductivity. Specifically, we explore and utilize the ability to use an array of Gaussian conductivity gratings as fully reflecting mirrors for surface plasmon polaritons (SPPs) propagating along a two-dimensional graphene sheet sandwiched between two dielectric materials. Graphene supports SPPs in the near-infrared to terahertz (THz) regime of the electromagnetic spectrum compared to those observed in metal-dielectric systems. Our resonator is fundamentally different from other similar published resonator designs because the distributed reflectors provide light confinement in both the horizontal and the vertical directions. As a result, the resonator is compact in the vertical-direction as we no longer use traditional mirrors or dielectric assisted gratings. Besides, conventional resonator designs only support a single, fixed resonant frequency, set by the mirror reflectivity and the cavity material’s properties. The versatility of graphene is that its Fermi energy can be electrically varied, thus allowing us to change the peak reflectivity of the graphene Bragg-grating without physically changing its physical dimensions. Therefore, by varying the Bragg wavelength, we can shift the resonance frequency of the cavity. One use of our resonator is in plasmonic lasers. We illustrate this use by analyzing the resonator parameters such as the linewidth and the quality factor of the plasmonic resonator.
Self-calibration of a variable-line-spacing grating for an absolute optical encoder with a Fizeau interferometer
Authors: Xiong Xin , Quan Lue , Shimizu Yuki , Matsukuma Hiraku , Gao Wei 
Published: February 2021

Abstract
The principle of the self-calibration method for the evaluation of a planar scale grating having a constant pitch is extended to realize the evaluation of the pitch distribution of a planar scale grating having variable line spacings (VLSs) along the X- and Y-directions. In the conventional self-calibration method, the wavefronts in the zeroth-order diffracted beam and the first-order diffracted beams observed by a Fizeau interferometer arranged in the Littrow configuration were employed to evaluate the pitch deviation of a scale grating. The arithmetic operation with the wavefront data realizes the evaluation of the pitch deviation over a large area in a short time, while cancelling the influence of the out-of-flatness of a scale grating. Meanwhile, theoretical equations in the conventional self-calibration method cannot be directly applied to the evaluation of a VLS grating due to its unique properties of the pitch distribution. In this paper, major modifications are thus made to the conventional theoretical equations for deriving the pitch distribution of a VLS grating. To verify the performance of the newly proposed method, the pitch distribution of a VLS grating employed in a commercial planar absolute encoder is evaluated in experiments.
A review on factors that affect surface charge accumulation and charge-induced surface flashover
Authors: Yuan Mengqiang , Zou Liang , Li Zongze , Pang Long , Zhao Tong , Zhang Li , Zhou Jierui , Xiao Peng , Akram Shakeel , Wang Zezhong , He Shun 
Published: February 2021

Abstract
The surface charge accumulation is very likely to trigger the surface flashover, which limits the large-scale application of DC GIL/GIS. This article comprehensively reviews the effect of six factors, including insulator-electrode shape, surface roughness of the insulator and conductor, metal particles, temperature, humidity, and gas type, on the insulator surface charging property. Furthermore, three models i.e. ‘analogous ineffective region’ expansion model, charge cluster triggered surface flashover model, and synergistic model of adsorbed gas, revealing the mechanism of charge triggered surface flashover phenomenon are reviewed and discussed. Future work from the perspective of theoretical analysis and engineering application are suggested in this field.
Bimetallic oxygen electrocatalyst derived from metallocenes doped MOFs
Authors: Cheng Guojie , Wu Guangyao , Li Han , Liu Shucheng , Liu Yi 
Published: February 2021

Abstract
Herein, metallocens (ferrocene, ruthenocene and cobaltocene) were in situ hybridized with two dimensional metal-organic frameworks (MOFs) via an improved inter-diffusion approach. The metallocens@MOFs hybrids were direct carbonized and transformed to Fe(Ru,Co)–Co@C composites. These bimetallic electrocatalysts show remarkable oxygen evolution reaction (OER) activity by taking advantage of the synergetic effect between the binary metals. Among of them, the obtained Fe–Co@C exhibits lower overpotential (320 mV at 10 mA cm−2) and satisfactory stability toward OER. The study presents a novel and facile strategy to synthesize low-cost bimetallic catalyst, showing great promise in electrocatalysis of oxygen.
The size effect in adhesive contact on a gradient nanostructured coating
Authors: Li Peixing , Liu Tie-Jun 
Published: February 2021

Abstract
The adhesive contact problem between a rigid cylindrical punch and a gradient nanostructured (GNS) coating is investigated by considering the size effect. The laminated plate model is applied to characterize the material properties of a GNS coating in plane strain couple stress elasticity. By using the Fourier integral transform and transfer matrix method, the governing integral equation(s) for the two-dimensional adhesive contact problem are obtained. Numerically calculated results are presented to analyse the effect of characteristic material length, the adhesion parameter and nonhomogeneous parameters on the mechanical response of the GNS coating for the adhesive contact problem. We explore the nanoscale contact of a GNS coating with shear modulus varying as a function of depth according to an exponential function or the power-law function. The present results provide a way to improve the contact deformation and damage to nanoelectromechanical systems by adjusting the gradient index of the GNS coating.
Highly stretchable and self-foaming polyurethane composite skeleton with thermally tunable microwave absorption properties
Authors: Ye Fengchao , He Xinsheng , Zheng Jiajia , Li Yancheng , Li Mengjia , Hu Zhonglue , Wang Sisi , Tong Guoxiu , Li Xiping 
Published: February 2021

Abstract
Stretchable and lightweight polymer composite material possessing tunable microwave absorption (MA) properties under thermal radiations remain a significant challenge. Here, we proposed a facile strategy to fabricate stretchable, magnetic composite skeletons by incorporating the tadpole-like CNTs@Fe3O4 nanoparticles into self-foaming polyurethane (PU) matrix and the electromagnetic responsive of CNTs@Fe3O4/PU composite foams with different CNTs contents under heating−cooling cycle in a temperature range of 253 −333 K were carefully investigated. Enhanced complex permittivity and shifting peak frequency were observed at elevated temperatures. For instance, the 70-CNTs@Fe3O4/PU sample with 15 wt% loading content at 333 K exhibits excellent MA properties including a minimum reflection loss (RLm) of −66.9 dB and ultrabroad effective frequency bandwidth (RL ≤ −20 dB) of 9.98 GHz at the thickness of 1.58−3.37 mm. Meanwhile, great recoverability in terms of RL-f profile was achieved in the process of thermal cooling back to 253 K. Such adjustable MA property was attributed to the well-matched impedance and dramatic attenuation ability, benefiting from the temperature-dependant electrical conductivity, abundant interfacial polarization and interior microcellular structures. Besides, the rising temperature increased the sample elongation and electrical conductivity with a slight sacrifice of maximum tensile strength. This stretchable PU skeleton with a unique assembly of CNTs and Fe3O4 nanoparticles are expected to be promising candidates as smart absorbers for application in the harsh environments.
Homemade experiment for understanding the fluid continuity principle
Authors: Nugraha M G , Purwana U , Parwati S , Kirana K H 
Published: February 2021

Abstract
In science learning, the experiment is an essential activity to facilitate students to discover and develop knowledge as well as to enhance scientific process skills and self-confidence. This study aims to create a simple experimental apparatus related to the principle of fluid continuity that can be made and conducted by the teacher and student as a learning media. Basic tools were used to assemble this homemade experiment and a free video analysis software, Tracker, was used to determine and analyse the fluid velocity. The experimental results showed that the fluid flows faster in the small hose than the larger one, which is in line with the fluid continuity principle. Nevertheless, there is a slightly different volumetric water flux (Q) in both hoses.
A novel 2D/3D hierarchical registration framework via principal-directional Fourier transform operator
Authors: Yang Keke , Luo Yang , Zhao Yiwen , Su Shun , Qu Danyang , Zhao Xingang , Song Guoli 
Published: February 2021

Abstract
An effective registration framework between preoperative 3D computed tomography and intraoperative 2D x-ray images is crucial in image-guided therapy. In this paper, a novel 2D/3D hierarchical registration framework via principal-directional Fourier transform operator (HRF-PDFTO) is proposed. First, a PDFTO was established to obtain the in-plane translation and rotation invariance. Then, an initial free template-matching approach based on PDFTO was utilized to avoid initial value assignment and expand the capture range of registration. Finally, the hierarchical registration framework, HRF-PDFTO, was proposed to reduce the dimensions of the registration search space from n
6 to n
2. The experimental results demonstrated that the proposed HRF-PDFTO has good performance with an accuracy of 0.72 mm, and a single registration time of 16 s, which improves the registration efficiency by ten times. Consequently, the HRF-PDFTO can meet the accuracy and efficiency requirements of 2D/3D registration in related clinical applications.
Four-dimensional inverse-geometry computed tomography: a preliminary study
Authors: Kim Kyeong-Hyeon , Shin Dong-Seok , Kang Sang-Won , Kang Seong-Hee , Kim Tae-Ho , Chung Jin-Beom , Suh Tae Suk , Kim Dong-Su 
Published: February 2021

Abstract
This study introduces and evaluates respiratory-correlated four-dimensional (4D) inverse geometry computed tomography (IGCT). The projection data of the IGCT were acquired in a single gantry rotation over 120 s. Three virtual phantoms—static Defrise, 4D Shepp–Logan, and 4D extended cardiac-torso (XCAT)—were used to obtain projection data for the IGCT and cone-beam computed tomography (CBCT). The projection acquisition parameters were determined to eliminate vacancies in the Radon space for an accurate rebinning process. Phase-based sorting was conducted within 10 phase bins, and the sorted projection data were binned into a cone beam geometry. Finally, Feldkamp–Davis–Kress reconstruction was conducted independently at each phase. The reconstructed images were compared using the structural similarity index measure (SSIM) and root mean square error (RMSE). The vertical profile of the Defrise reconstruction image was uniform, and the cone beam artefact was reduced in the IGCT image. Under an ideal projection acquisition condition, the mean coronal plane SSIMs of the Shepp–Logan and 4D XCAT phantoms were 0.899 and 0.706, respectively, which were higher than those of the CBCT (0.784 and 0.623, respectively). Similarly, the mean RMSEs of the coronal plane IGCT (0.036 and 0.158) exhibited an improvement over those of the CBCT (0.165 and 0.261, respectively). The mean standard deviations of the SSIM and RMSE were lower for IGCT than for CBCT. In particular, the SSIM and RMSE of the sagittal and coronal planes of the Shepp–Logan IGCT images were stable in all phase bins; however, those of the CBCT changed depending on the phase bins. Poor image quality was observed for IGCT under inappropriate conditions. This was caused by a vacancy in the Radon space, owing to an inappropriate scan setting. Overall, the proposed 4D IGCT exhibited better image quality than conventional CBCT.
Evaluation of the effectiveness of electrical muscle stimulation on human calf muscles via frequency difference electrical impedance tomography
Authors: Sun Bo , Baidillah Marlin Ramadhan , Darma Panji Nursetia , Shirai Tomoyuki , Narita Kosei , Takei Masahiro 
Published: February 2021

Abstract

Objectives. The human skeletal muscle responds immediately under electrical muscle stimulation (EMS), and there is an immediate physiological response in human skeletal muscle. Non-invasive quantitative analysis is at the heart of our understanding of the physiological significance of human muscle changes under EMS. Response muscle areas of human calf muscles under EMS have been detected by frequency difference electrical impedance tomography (fd-EIT). Approach. The experimental protocol consists of four parts: pre-training (pre), training (tra), post-training (post), and relaxation (relax) parts. The relaxation part has three relaxation conditions, which are massage relaxation (MR), cold pack relaxation (CR), and hot pack relaxation (HR). Main results. From the experimental results, conductivity distribution images σ

p
(p means protocol = pre, tra, post, or relax) are clearly reconstructed by fd-EIT as response muscle areas, which are called the M
1 response area (composed of gastrocnemius muscle) and the M
2 response area (composed of the tibialis anterior muscle, extensor digitorum longus muscle, and peroneus longus muscle). A paired samples t-test was conducted to elucidate the statistical significance of spatial-mean conductivities 〈σ

p
〉
M1 and 〈σ

p
〉
M2 in M
1 and M
2 with reference to the conventional extracellular water ratio β

p
by bioelectrical impedance analysis. Significance. From the t-test results, 〈σ

p
〉
M1
and 〈σ

p
〉
M2 have good correlation with β

p
. In the post-training part, 〈σ

post
〉 and β

post
were significantly higher than in the pre-training part (n = 24, p < 0.001). The relax–pre difference ratios of spatial-mean conductivity Δ〈σ

relax–pre
〉 and the relax–pre difference ratios of extracellular water ratio Δβ

relax–pre
in both MR and CR were lower; on the contrary, the Δ〈σ

relax–pre
〉 and Δβ

relax–pre
in HR were significantly higher than those in post–pre difference ratios of spatial-mean conductivity Δ〈σ

post–pre
〉 (n = 8, p < 0.05). The reason for the changes in 〈σ

p
〉
M1 and 〈σ

p
〉
M2 are caused by the changes in muscle extracellular volumes. In conclusion, fd-EIT satisfactorily evaluates the effectiveness of human calf muscles under EMS.