bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric and magnetic properties of holmium and ytterbium titanates
Authors: Bogolubskiy A. S. , Klepikova A. S. , Rinkevich A. B. , Neverov V. N. , Nemytova O. V. , Koroleva M. S. , Piir I. V. , Perov D. V.
Published: January 2021

Ytterbium and holmium titanates have been synthesized and their dielectric and magnetic properties have been investigated. The frequency dependences of the permittivity at T = 77 and 300 K, and measured magnetization curves and temperature dependences of the magnetic susceptibility in fields up to 30 kOe and at temperatures from 2 K to 50 K have been obtained. The properties of the doped and undoped titanates have been compared. Based on the temperature dependences of the magnetic susceptibility, the magnetic dipole and exchange couplings in the titanates have been analyzed.
Multi-parameter Tikhonov regularization-based OTPA with application to ship-radiated noise evaluation
Authors: Li Ruibiao , Bu Wenjun
Published: January 2021

The purpose of this study is to reduce the errors caused by the inversion of the transfer function (TF) matrix when evaluating ship-radiated noise by operational transfer path analysis. The singular value decomposition (SVD), generalized cross validation (GCV), and L-curve methods are separately introduced to evaluate the TF matrix, and the performances are compared. In order to overcome the shortcomings of the aforementioned methods and further reduce the errors, the optimized multi-parameter (M-P) Tikhonov regularization method based on the criterion of condition number is proposed to create an optimal regularization parameter to evaluate the TF matrix herein. The feasibility is verified with a double-layer cylindrical shell model experiment in Thousand Islets Lake. The obtained results indicate that the average error of M-P Tikhonov regularization is reduced by up to 0.38 dB compared with that of the L-curve, 0.68 dB compared with that of the GCV, and 1.34 dB compared with that of the SVD under various combinations of noise levels, which can provide guidance for ship-radiated noise evaluation in engineering applications.
Experimental study on surface ignition reaction evolution of pressed PBX-A under inertial mass confinement
Authors: Qiu Tian , Wen Shang-gang , Li Tao , Hu Haibo , Dai Xiaogan , Chai Chuan-guo , Fu Hua , Shang Hailin , Wen Yushi
Published: January 2021

An experimental apparatus was designed to study the non-shock initiation reaction evolution process of a HMX (cyclotetramethylenete-tranitramine)-based pressed PBX (Plastic Bonded Explosive)-A column under the main constraint of the inertial mass of the explosive bulk, with strong bottom and circumferential confinements and with the strength of a PMMA plate cover as the threshold to control the internal reaction pressure. The HMX-based pressed PBX-A column was ignited by black powder. The experimental results show that the reaction violence was quite mild, and the estimated amount of explosive consumed at the time of the PMMA plate cracking was only 1.8% of the thickness. The velocity curve of the constrained surface shows that the internal reaction pressure at the initial stage of the structural deformation shows the “quasi-isobaric” characteristic, and the estimated reaction pressure at this stage was about 157.41 MPa.
Periodicity, linearizability, and integrability in seed mutations of type AN(1)
Authors: Nobe Atsushi , Matsukidaira Junta
Published: January 2021

In the network of seed mutations arising from a certain initial seed, an appropriate path emanating from the initial seed is intendedly chosen, noticing periodicity of exchange matrices in the path each of which is assigned to the generalized Cartan matrix of type AN(1). Then, the dynamical property of seed mutations along the path, which is referred to as of type AN(1), is intensively investigated. The coefficients assigned to the path form certain N monomials that possess periodicity with period N under seed mutations and enable us to obtain the general terms of the coefficients. The cluster variables assigned to the path of type AN(1) also form certain N Laurent polynomials possessing the same periodicity as the monomials generated by the coefficients. These Laurent polynomials lead to a sufficient number of conserved quantities of the dynamical system derived from cluster mutations along the path. Furthermore, by virtue of the Laurent polynomials with periodicity, the dynamical system is non-autonomously linearized and its general solution is concretely constructed. Thus, seed mutations along the path of type AN(1) exhibit discrete integrability.
Apparatus for controlled microwave exposure of aerosolized pathogens
Authors: Hoff Brad W. , McConaha Jeremy W. , Cohick Zane W. , Franzi Matthew A. , Enderich Daniel A. , Revelli David , Cox Jason , Irshad Hammad , Pohle Hugh H. , Schmitt-Sody Andreas , Schaub Samuel C. , Baros Anthony E. , Lewis Naomi C. , Luginsland John W. , Lanagan Michael T. , Perini Steven
Published: January 2021

A set of three apparatus enabling RF exposure of aerosolized pathogens at four chosen frequencies (2.8 GHz, 4.0 GHz, 5.6 GHz, and 7.5 GHz) has been designed, simulated, fabricated, and tested. Each apparatus was intended to operate at high power without leakage of RF into the local environment and to be compact enough to fit within biocontainment enclosures required for elevated biosafety levels. Predictions for the range of RF electric field exposure, represented by the complex electric field vector magnitude, that an aerosol stream would be expected to encounter while passing through the apparatus are calculated for each of the chosen operating frequencies.
Evaluation of void nucleation, growth, and coalescence parameters for HCP-Zr at extreme strain rates
Authors: Zhou Wengang , Chen Wenjun , Yuan Jiajun
Published: January 2021

Void nucleation, growth, and coalescence at extreme strain rates in ductile metals with weak mechanical anisotropies, e.g., copper, iron, and aluminum, have been extensively investigated. However, the atomic-scale fracture properties of strongly anisotropic metals, especially hexagonal close-packed (HCP) metals, at ultrahigh strain rates have rarely been studied. We have investigated the nucleation, growth, and coalescence of voids in HCP-Zr under isotropic-triaxial tension using molecular dynamics (MD) and void nucleation and growth (NAG) models. The effects of temperature were also examined by MD. The void evolution predicted by MD corresponded to that predicted by the NAG model and is divided into three stages, i.e., an initial nucleation stage, an exponential growth stage, and a linear stage. The nucleation threshold Pn0 is very sensitive to temperature, while the growth threshold Pg0 decreases slightly with increasing temperature. The initial NAG parameters were evaluated by an improved optimized genetic algorithm. In addition, we adjusted the NAG parameters until the history of the void volume fraction calculated by these parameters was exactly the same as that calculated by MD. This study predicts comprehensive NAG parameters for HCP-Zr under extreme conditions, providing a valuable reference for future studies of dynamic damage in HCP materials.
Full-frequency GW without frequency
Authors: Bintrim Sylvia J. , Berkelbach Timothy C.
Published: January 2021

Efficient computer implementations of the GW approximation must approximate a numerically challenging frequency integral; the integral can be performed analytically, but doing so leads to an expensive implementation whose computational cost scales as O(N6), where N is the size of the system. Here, we introduce a new formulation of the full-frequency GW approximation by exactly recasting it as an eigenvalue problem in an expanded space. This new formulation (1) avoids the use of time or frequency grids, (2) naturally obviates the need for the common “diagonal” approximation, (3) enables common iterative eigensolvers that reduce the canonical scaling to O(N5), and (4) enables a density-fitted implementation that reduces the scaling to O(N4). We numerically verify these scaling behaviors and test a variety of approximations that are motivated by this new formulation. The new formulation is found to be competitive with conventional O(N4) methods based on analytic continuation or contour deformation. In this new formulation, the relation of the GW approximation to configuration interaction, coupled-cluster theory, and the algebraic diagrammatic construction is made especially apparent, providing a new direction for improvements to the GW approximation.
Effect of voltage divider layer on self-current compliance resistive switching in Ta/TaOx/ITO structure with an ultra-low power consumption
Authors: Zhao Jinshi , Guo Shuqin , Li Jiacheng , Li Yingchen , Zhou Liwei
Published: January 2021

Based on the Ta/TaOx/ITO structure, self-current compliance behavior in the resistive switching (RS) properties was investigated. The formation and rupture of metallic indium (In) conducting filaments (CFs), which contributes to the RS in this device, are confirmed by the variable temperature electrical test combined with X-ray photoelectron spectroscopy (XPS) analysis. It showed high uniformity and endurance performance up to 108 switching cycles, including a lower power consumption. The excellent electrical performance can be attributed to the role of a series resistor of ITO because the adverse effects of the voltage (or current) overshooting can be efficiently suppressed, resulting in the controllability of the In CF formation and rupture. The XPS depth profile results confirmed the oxygen exchange at the TaOx/ITO interface, combined with the Ohmic conduction mechanism at low resistance state, indicating that the ITO interface acts as the series resistor rather than the Schottky barrier.
Expansion and combustion of droplets that contain long-chain alcohol alternative fuels
Authors: Li Fengyu , Tian Junjian , Han Kai , Bao Lin , Meng Kesheng , Lin Qizhao
Published: January 2021

This paper studies the expansion, micro-explosion, and combustion behaviors of base fuels blended with long-chain alcohols. Diesel, biodiesel, and aviation kerosene are chosen as the base fuels, while n-butanol and n-pentanol are representative long-chain alcohols. Upon addition of a long-chain alcohol, deformation of the blended-fuel droplet becomes more violent. Expansion and ejection of internal liquid and gas occur throughout the process; larger proportions of long-chain alcohols lead to larger ejection holes. The degree of expansion first increases and then decreases with the proportion of alcohol. The effect of the alcohol type on d* (normalized droplet diameter) is substantial at low φ (volume fraction of long-chain alcohol) but negligible at high φ. The aviation kerosene-based fuel exhibits the smallest changes in d*. The effects of φ and the alcohol type on the micro-explosion delay time are also analyzed. The ignition delay time of the diesel-based fuel decreases monotonically with the increasing alcohol proportion and that of the biodiesel-based fuel first decreases and then increases, while that of the aviation kerosene-based fuel increases and then decreases. The combustion rate of a pure base fuel accelerates upon addition of alcohol. The ignition delay time is greatly shortened at higher temperatures, and the combustion duration shortens significantly at temperatures lower than 800 °C. The biodiesel-based fuel offers the shortest ignition delay time and the longest combustion duration, while aviation kerosene exhibits the opposite characteristics. Finally, the micro-explosion and comprehensive combustion indices are proposed to estimate the comprehensive micro-explosion and combustion performances, respectively, of blended fuels.
ZFP57 dictates allelic expression switch of target imprinted genes
Authors: Jiang Weijun , Shi Jiajia , Zhao Jingjie , Wang Qiu , Cong Dan , Chen Fenghua , Zhang Yu , Liu Yuhan , Zhao Junzheng , Chen Qian , Gu Linhao , Zhou Wenjia , Wang Chenhang , Fang Zhaoyuan , Geng Shuhui , Xie Wei , Chen Luo-Nan , Yang Yang , Bai Yun , Lin Haodong , Li Xiajun
Published: January 2021

Significance

This study provides further proof for ZFP57 as a master regulator of genomic imprinting since it maintains DNA methylation at most known imprinted regions and regulates allelic expression of the corresponding imprinted genes. We propose two alternate allelic switch models for ZFP57-dependent regulation of parent-of-origin–dependent expression of the imprinted genes based on allelic and quantitative expression analyses of the imprinted genes. Our results also shed light on the mechanistic link between DNA methylation imprint and monoallelic expression of the imprinted genes. The results indicate that ZFP57 regulates allelic expression of clustered imprinted genes through maintenance of DNA methylation at the imprinting control regions.
Tissue-specific dynamic codon redefinition in
Drosophila
Authors: Hudson Andrew M. , Szabo Nicholas L. , Loughran Gary , Wills Norma M. , Atkins John F. , Cooley Lynn
Published: January 2021

Significance

Here we describe efficient, developmentally regulated stop codon readthrough of the
Drosophila kelch
gene. Stop codon readthrough is a form of translational recoding in which a UGA, UAG, or UAA codon is redefined as a sense codon, allowing translation to continue. We show that readthrough of the
kelch
stop codon occurs at highest efficiency specifically in neurons of the central nervous system (CNS), and we define a short sequence near the
kelch
ORF1 UGA codon that stimulates efficient readthrough. We also show that stop codon readthrough for three additional genes occurs with high efficiency in the CNS, suggesting that stop codon readthrough may contribute significantly to the neuronal proteome.
Neural network interpretation using descrambler groups
Authors: Amey Jake L. , Keeley Jake , Choudhury Tajwar , Kuprov Ilya
Published: January 2021

Significance

Artificial neural networks are famously opaque—it is often unclear how they work. In this communication, we propose a group-theoretical way of finding out. It reveals considerable internal sophistication, even in simple neural networks: our nets apparently invented an elegant digital filter, a regularized integral transform, and even Chebyshev polynomials. This is a step toward saving reductionism. For centuries, the philosophical approach to science has been to find fundamental laws that govern reality, to test those laws, and to use their predictive power. Black-box neural networks amount to blasphemy within that school, but they are irresistible because they “just work.” Explaining how they work is a notoriously difficult problem, to which this paper offers a partial solution.
Heat stress destabilizes symbiotic nutrient cycling in corals
Authors: Rädecker Nils , Pogoreutz Claudia , Gegner Hagen M. , Cárdenas Anny , Roth Florian , Bougoure Jeremy , Guagliardo Paul , Wild Christian , Pernice Mathieu , Raina Jean-Baptiste , Meibom Anders , Voolstra Christian R.
Published: January 2021

Significance

Ocean warming is causing repeated mass coral bleaching, leading to catastrophic losses of coral reefs worldwide. Our ability to slow or revert this decline is hampered by an incomplete understanding of the processes underlying the breakdown of the coral–algal symbiosis. Here, we show that heat stress destabilizes the nutrient cycling between corals and their endosymbiotic algae long before bleaching becomes apparent. Notably, increased metabolic energy demands shift the coral–algal symbiosis from a nitrogen- to a carbon-limited state, reducing translocation and recycling of photosynthetic carbon. This effectively undermines the ecological advantage of harboring algal symbionts and directly contributes to the breakdown of the coral–algal symbiosis during heat stress.
Climate change adaptation and mitigation.
Authors: Taylor Mary
Published: January 2021

Climate is a description of the typical weather conditions experienced over a specific period of time (usually a few decades) and for a particular location and time of year. Climate also describes typical year-to-year variations and weather extremes of a region. Natural variation of the Earth's climate occurs over a wide range of timescales. These timescales can be year-to-year and decade-to-decade and can be due to a range of forcings, both internal, such as the El Niño-Southern Oscillation (ENSO) and external, such as the amount of incoming solar radiation to the climate system (Bindoff et al., 2013; Hartmann et al., 2013). Changes in the Earth's position relative to the Sun produced swings between glacial and interglacial conditions over much longer timescales (Masson-Delmotte et al., 2013). However, since the beginning of the Industrial Revolution the planet has experienced rapid changes in the climate, referred to as climate change (Stocker et al., 2013).
Mathematical modelling.
Authors: Durner Ed Rutgers
Published: January 2021

Plants are studied to understand their growth and development so that their quality and productivity can be optimised. Models are developed that can be simple and descriptive, or quite complex with numerous mathematical equations; their level of complexity is linked to their purpose. This summary serves as an introduction to mathematical models in horticulture. It is not a manual for modelling itself, but rather an overview of how important mathematical models are in horticultural production. Mathematical models are used extensively in horticulture both extrinsically, i.e. when calculating chilling hour accumulations and intrinsically, i.e. when applying fertilizer to a crop. In chilling calculations, developed models are used directly. Fertilizer recommendations were probably developed using a mathematical model. The first part of this article discusses models in general and reviews general characteristics of mathematical models. The second part outlines the major uses of mathematical modelling in modern horticultural production. Presentations of specific models are limited in order to present a general discussion of models with examples that will interest most horticulturists.
Harvesting.
Authors: Morgan Lynette
Published: January 2021

Harvesting involves gathering a mature crop from the field where it has been grown, and transporting it for postharvest handling with minimal damage or losses. Once the earliest crops came under cultivation, harvesting processes did not initially change much from those used for gathering from the wild, i.e. hand harvesting and basic stone or wooden tools used for cutting and digging. In Egypt, the first crops of wheat were cut with flint blades; the scythe was introduced into Europe by the Romans, but the sickle had been in widespread use for centuries. By the 1800s labour shortages in both Europe and the Western United States saw the development of new and more efficient methods of harvesting grain crops. The first reaper equipment pushed by horses with shears cutting the wheat in front was developed in the early 1800s. The early 'Bell' reapers could cut 10 acres a day compared with a hand worker at only 0.3 acres a day. While the first reapers cut wheat stalks in the field at harvest, the process still required workers to manually pick them up; later models would cut and stack stalks. Harvesting equipment and machinery progressed through to steam powered, and then onto internal combustion engines in the early 20th Century. By the 1930-1960s mechanical harvesters for grain, beans and cotton became increasingly available, but many fruits, flowers, vegetables and other crops were still largely harvested by hand. By the mid-1960s the self-propelled tomato fruit harvester was developed in response to concerns that expected shortages of labourers would prevent harvest of the increasing volumes of processing tomatoes being grown through the 1950s. Later inventions and developments in mechanical harvesting equipment then yielded further labour saving and product quality improvements. Increasing levels of harvest mechanisation allowed many farmers to remain profitable in highly competitive markets by lowering the costs of production and removing the reliance on finding a suitable labour force during the harvest season. Despite this, a large proportion of fruit and vegetable crops destined for fresh consumption worldwide are still hand harvested, while mechanised harvest now dominates large scale production of major agronomic crops such as wheat, maize, soybean, cotton, rice, potatoes and other crops destined for processing.
Occupational health and safety in horticulture.
Authors: Morgan Lynette
Published: January 2021

According to the International Labour Organisation (ILO), health is defined as the promotion and maintenance of the highest degree of physical, mental and social well-being of workers in all occupations, while safety is freedom from unacceptable risk or harm. Occupational health and safety (OHS or OSH) is specifically concerned with the health, safety and welfare of people in their work environment, but it also encompasses any other people who may be present onsite, including customers, friends and family members, visitors and contractors. In addition it considers the fact that many horticultural properties have staff and owners who reside on the site.
Mussaenda philippica (queen of Philippines).
Authors: Rojas-Sandoval Julissa
Published: January 2021

Mussaenda philippica is a large shrub or small tree that is native to the Philippines and frequently cultivated as an ornamental in tropical regions. It can be found growing in parks, botanical gardens, private and public gardens and along roadsides and highways. Although plants in cultivation usually do not produce fruits, they can spread vegetatively by stem fragments and cuttings. M. philippica is a species of environmental concern because it can grow up to 8 m tall and has a wide spreading crown that may shade out other vegetation including native plant species.
Effect of hydroxychloroquine on angiographic progression in routine treatment of Takayasu arteritis
Authors: Rongyi Chen , Zongfei Ji , Jiang Lin , Sifan Wu , Lingying Ma , Ying Sun , Wenshu Yu , Xiaomeng Cui , Xiufang Kong , Xiaomin Dai , Lili Ma , Yanshan Li , Lindi Jiang
Published: January 2021

Objectives

Hydroxychloroquine (HCQ), an anti-malarial drug, is widely used in the treatment of rheumatic diseases. However, the benefits of HCQ in the treatment of Takayasu arteritis (TA) remain unclear, especially in terms of alleviation of vascular progression.

Methods

This longitudinal observational retrospective study was based on the East China TA cohort. Patients received routine treatment with prednisone and immunosuppressants. Fifty TA patients who underwent magnetic resonance angiography two times within a 1.5-year follow-up period of monitoring vascular changes were divided into HCQ and non-HCQ groups according to whether HCQ was prescribed. Changes in angiographic features were compared. Multivariate Cox regression analysis was employed to further validate the results.

Results

Of 50 TA patients, 21 were prescribed HCQ. The two groups shared a similar disease course, vascular types, prednisone with immunosuppressants intervention strategy, globin level, and disease remission rate at 6 months. The HCQ group showed greater reduction in the inflammatory indices erythrocyte sedimentation rate and C-reactive protein (CRP) level (p < .05), and a significantly lower incidence of angiographic progression than the non-HCQ group (19.0% vs. 51.7%, p = .035). After adjustment for age and usage of tocilizumab, angiographic progression was found to be independently associated with CRP (hazard ratio [95% confidence interval], HR [95% CI]: 1.102 [1.000–1.024], p = .046), and the usage of HCQ (HR [95% CI]: 0.266 [0.075–0.940], p = .040).

Conclusion

HCQ enhanced the anti-inflammatory effect of routine treatment strategies with prednisone and immunosuppressants, and alleviated angiographic progression in TA.
Characteristics of rheumatoid arthritis with immunodeficiency-associated lymphoproliferative disorders to regress spontaneously by the withdrawal of methotrexate and their clinical course: A retrospective, multicenter, case–control study
Authors: Kuramoto Nobuo , Saito Shuntaro , Fujii Takao , Kaneko Yuko , Saito Rintaro , Tanaka Masao , Takada Hideto , Nakano Kazuhisa , Saito Kazuyoshi , Sugimoto Naoki , Sasaki Sho , Harigai Masayoshi , Suzuki Yasuo
Published: January 2021

Objective

To investigate clinical characteristics and time course of lymphoproliferative disorders (LPDs) in rheumatoid arthritis (RA) patients after methotrexate (MTX) discontinuation, in those who achieved spontaneous regression (SR).

Methods

We retrospectively reviewed clinical data from RA patients with LPDs obtained from eight institutions between 2000 and 2017 and compared clinical and pathological findings between SR and non-SR groups.

Results

Among 232 RA patients with LPDs, 216 were treated with MTX at the onset of LPD and 144 (66.7%) achieved SR after MTX discontinuation. Higher MTX doses, high titers of anti-CCP antibodies (>13.5 U/mL), and lower LDH and soluble IL-2 receptor levels were associated with SR. Lymphocyte count was decreased at LPD onset and increased at 2 weeks after MTX discontinuation in the SR group. Epstein–Barr virus-positive mucocutaneous ulcer, reactive lymphoid hyperplasia and unclassifiable B-cell lymphoma, were more frequent in the SR than in the non-SR group. In multivariable analysis, diffuse large B-cell lymphomas was an independent predictive factor for non-SR. In the patients with SR, 73.9% achieved partial or complete regression as early as 2 weeks after MTX discontinuation.

Conclusion

SR and non-SR in RA patients with LPDs after MTX discontinuation were associated with certain clinical characteristics.
Hermann von Helmholtz and the aesthetics of the acoustics
Authors: Mion Marta , Martini Alessandro
Published: January 2021

Objective

The aim of this study was to honour the 100-year birth jubilee of Hermann von Helmholtz (1821–1894), and his studies on the ‘aesthetics of acoustic’.

Methods

We will present original documents and historical references.

Results

After a brief section of biographical notes on von Helmholtz, we present the results of his acoustic studies and the analysis of his work ‘On the sensation of tone’.

Conclusion

von Helmholtz devoted part of his researches to acoustics, also creating new tools of his invention as his eponymy named resonators.
Cep57 and Cep57L1 maintain centriole engagement in interphase to ensure centriole duplication cycle
Authors: Ito Kei K. , Watanabe Koki , Ishida Haruki , Matsuhashi Kyohei , Chinen Takumi , Hata Shoji , Kitagawa Daiju
Published: January 2021

Centrioles duplicate in interphase only once per cell cycle. Newly formed centrioles remain associated with their mother centrioles. The two centrioles disengage at the end of mitosis, which licenses centriole duplication in the next cell cycle. Therefore, timely centriole disengagement is critical for the proper centriole duplication cycle. However, the mechanisms underlying centriole engagement during interphase are poorly understood. Here, we show that Cep57 and Cep57L1 cooperatively maintain centriole engagement during interphase. Codepletion of Cep57 and Cep57L1 induces precocious centriole disengagement in interphase without compromising cell cycle progression. The disengaged daughter centrioles convert into centrosomes during interphase in a Plk1-dependent manner. Furthermore, the centrioles reduplicate and the centriole number increases, which results in chromosome segregation errors. Overall, these findings demonstrate that the maintenance of centriole engagement by Cep57 and Cep57L1 during interphase is crucial for the tight control of centriole copy number and thus for proper chromosome segregation.
ANO5 ensures trafficking of annexins in wounded myofibers
Authors: Foltz Steven J. , Cui Yuan Yuan , Choo Hyojung J. , Hartzell H. Criss
Published: January 2021

Mutations in ANO5 (TMEM16E) cause limb-girdle muscular dystrophy R12. Defective plasma membrane repair is a likely mechanism. Using myofibers from Ano5 knockout mice, we show that trafficking of several annexin proteins, which together form a cap at the site of injury, is altered upon loss of ANO5. Annexin A2 accumulates at the wound to nearly twice the level observed in WT fibers, while annexin A6 accumulation is substantially inhibited in the absence of ANO5. Appearance of annexins A1 and A5 at the cap is likewise diminished in the Ano5 knockout. These changes are correlated with an alteration in annexin repair cap fine structure and shedding of annexin-positive vesicles. We conclude that loss of annexin coordination during repair is disrupted in Ano5 knockout mice and underlies the defective repair phenotype. Although ANO5 is a phospholipid scramblase, abnormal repair is rescued by overexpression of a scramblase-defective ANO5 mutant, suggesting a novel, scramblase-independent role of ANO5 in repair.
Cardiomyopathic troponin mutations predominantly occur at its interface with actin and tropomyosin
Authors: Tobacman Larry S. , Cammarato Anthony
Published: January 2021

Reversible Ca2+ binding to troponin is the primary on-off switch of the contractile apparatus of striated muscles, including the heart. Dominant missense mutations in human cardiac troponin genes are among the causes of hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy. Structural understanding of troponin action has recently advanced considerably via electron microscopy and molecular dynamics studies of the thin filament. As a result, it is now possible to examine cardiomyopathy-inducing troponin mutations in thin-filament structural context, and from that to seek new insight into pathogenesis and into the troponin regulatory mechanism. We compiled from consortium reports a representative set of troponin mutation sites whose pathogenicity was determined using standardized clinical genetics criteria. Another set of sites, apparently tolerant of amino acid substitutions, was compiled from the gnomAD v2 database. Pathogenic substitutions occurred predominantly in the areas of troponin that contact actin or tropomyosin, including, but not limited to, two regions of newly proposed structure and long-known implication in cardiomyopathy: the C-terminal third of troponin I and a part of the troponin T N terminus. The pathogenic mutations were located in troponin regions that prevent contraction under low Ca2+ concentration conditions. These regions contribute to Ca2+-regulated steric hindrance of myosin by the combined effects of troponin and tropomyosin. Loss-of-function mutations within these parts of troponin result in loss of inhibition, consistent with the hypercontractile phenotype characteristic of HCM. Notably, pathogenic mutations are absent in our dataset from the Ca2+-binding, activation-producing troponin C (TnC) N-lobe, which controls contraction by a multi-faceted mechanism. Apparently benign mutations are also diminished in the TnC N-lobe, suggesting mutations are poorly tolerated in that critical domain.
Multilayer graphene frequency doubler using direct-current bias and reflector networks
Authors: Hou Ying , Ding Manlai , Fang Yong , Hou Xueshi , Zhong Xiaoling , Guo Yong , Guo Tingting
Published: January 2021

A multilayer graphene frequency doubler (GFD) with inductance–capacitor resonators (LCRs) and microstrip reflective stubs (MRS) is proposed in this paper. Graphene has strong nonlinear characteristics. Under the excitation of electromagnetic waves, the output power of odd harmonic of graphene is greater than that of even harmonic. Under the joint excitation of electromagnetic wave and bias voltage, the even harmonic output power of graphene is enhanced and the odd harmonic is suppressed, which is very suitable for making GFD. On the basis of analyzing the conductivity of graphene, the symbolically defined device model of multilayer graphene is established, and the model is applied to GFD circuit, the simulation results are basically consistent with the experimental data. The multiplier efficiency of graphene can be effectively improved by the bias voltage and LCR and the MRS. At an operating frequency of 0.65–1.15 GHz, the minimum conversion loss (CL) of the GFD is 20.57 dB when the input power is 16 dBm.
Dominant heating mechanisms in a surface barrier discharge
Authors: Gilbart B , Dickenson A , Walsh J L , Hasan M I
Published: January 2021

In computational models of atmospheric pressure surface barrier discharges (SBDs) the role of heating of the dielectric material and the quiescent gas is often neglected, impacting the accuracy of the calculated chemical kinetics. In this contribution, a two-dimensional fluid model of an SBD was developed and experimentally validated to determine the relative contribution of the dominant heat transfer mechanisms and to quantify the impact of discharge heating on the resultant chemistry. Three heating mechanisms were examined, including electron heating of the background gas due to inelastic collisions, ion bombardment of the dielectric surface and dielectric heating by the time-varying electric field. It was shown that electron heating of the background gas was not significant enough to account for the experimentally observed increase in temperature of the dielectric material, despite being the dominant heating mechanism of the gas close to the electrode. Dielectric heating was ruled out as the frequency response of typical dielectric materials used in SBD devices does not overlap with the experimentally observed power spectrum of an SBD excited at kHz frequencies. The ionic flux heating was found to be the dominant heating mechanism of the dielectric material and the downstream flow driven by the SBD. The largest impact of plasma heating on discharge chemistry was found in reactive nitrogen species (RNS) production, where the densities of RNSs increased when an appropriate treatment of heating was adopted. This had a marked effect on the discharge chemistry, with the concentration of NO2 increasing by almost 50% compared to the idealized constant temperature case.
The drag of photons by electric current in quantum wells
Authors: Budkin G V , Makhov I S , Firsov D A
Published: January 2021

The flow of electric current in quantum well breaks the space inversion symmetry, which leads to the dependence of the radiation transmission on the relative orientation of current and photon wave vector, this phenomenon can be named current drag of photons. We have developed a microscopic theory of such an effect for intersubband transitions in quantum wells taking into account both depolarization and exchange-correlation effects. It is shown that the effect of the current drag of photons originates from the asymmetry of intersubband optical transitions due to the redistribution of electrons in momentum space. We show that the presence of dc electric current leads to the shift of intersubband resonance position and affects both transmission coefficient and absorbance in quantum wells.
Accuracy of position tracking and fabrication of thin diameter sensor
Authors: Chen Xiangyan , Zhang Yanan , Qian Jinwu , Shen Linyong
Published: January 2021

The shape reconstruction of medical surgical instruments in robotic laryngeal surgery, positioning a needle to puncture a breast tumour, shape display during intestinal endoscopy, and positioning a cardiac vascular catheter, is affected by not only the end position and the shape reconstruction accuracy but also the diameter and curvature of the sensor owing to the limited application space. A sensor with a substrate is manufactured by pasting a fibre Bragg grating (FBG) on the surface of nitinol wire. The measuring range of the substrate is improved by applying a certain preload before glue injection. The sensor has the advantages of being less prone to breakage and greater durability but has a limited bending curvature and diameter. In minimally invasive surgery, the curvature of the body cavity is complex, and the space is narrow, and thus the FBG sensor must have a smaller diameter and good bending curvature. The present paper proposes a method of filling and encapsulating a small-diameter substrate sensor. A substrate-less sensor with a diameter of 1.5 mm and sensing length of 200 mm is encapsulated by improving the packaging positioning piece, current glue injection method, and packaging process. Four FBGs with two grating points for each fibre are distributed at 90° to each other, and four measuring points are obtained by wavelength division multiplexing and space division multiplexing. A calibration and shape reconstruction experiment is carried out for the shape sensor, while a packaging error compensation calibration method is introduced to improve the precision of shape reconstruction. Results of a two-dimensional experiment show that the shape reconstruction accuracy of the sensor on the plane bending is 2.71%. In a three-dimensional spiral experiment, the measurement accuracy of FBG shape sensor out-of-plane bending is 3.42%.
Facile synthesis of 2D α-MnO2 nanosheets for the removal of heavy metal ions
Authors: Li Hao , Gui Lin , Gao Zhanyang , Ren Feipeng , Zhang Honglei , Peng Ruichao
Published: January 2021

Removal of heavy metal ions (HMIs) has attracted great attentions due to the fact that they have serious effect on environment and human beings. Manganese oxide (MnO2) was widely used as absorbent for the HMIs removal on account of its low-cost, eco-friendly and biocompatibility. The modification of morphological and structure is recognized as the effective route to improve the adsorption capacity. In this work, 2D α-MnO2 nanosheets were synthesized by hydrothermal method with Al3+ additive. With the merits of high specific surface area, high dispersity in aqueous solution and abundant surface defects, 2D α-MnO2 nanosheets exhibited excellent HMIs adsorption performance. The maximum adsorption capacity of 2D α-MnO2 nanosheets reached 1.604 mmol g−1 (Pb2+) and 0.813 mmol g−1 (Cd2+), respectively and can maintain stable after five cycles. Besides, the established adsorption kinetics fitted well with pseudo-second-order adsorption kinetics model. Based on the above results, 2D α-MnO2 is efficient for the removal of HMIs and possesses remarkable practical application potential.
Strong adsorption, catalysis and lithiophilic modulation of carbon nitride for lithium/sulfur battery
Authors: Ji Lei , Jia Yongfeng , Wang Xia , Duan Limei , Li Weishan , Liu Jinghai , Zhang Yuegang
Published: January 2021

Lithium/sulfur (Li/S) batteries have emerged as one of the most promising next-generation energy storage systems with advantages of high theoretical energy density, low cost and environmental friendliness. However, problems regarding to severe shuttle effect of soluble polysulfide, poor electronic/ionic conductor of solid charged/discharged products (S8 and Li2S), and fatal swell of volume along with the growth of Li dendrites greatly deteriorate the sulfur utilization and capacity retention during extended charge–discharge cycles. With advantages of high nitrogen content, lithiophilic modulation and tunable charge density and charge transfer, carbon nitride (g-C3N4) has played a positive role in restricting the shuttle effects and dendrite formation. This minireview mainly discusses these research achievements of g-C3N4 in Li/S batteries, aiming to provide a basic understanding and direct guidance for further research and development of functionalized g-C3N4 materials in electrical energy storage. The two-dimensional (2D) structure of g-C3N4 with abundant hierarchical pores improves its accommodation capacity for sulfur by effectively confining the lithium polysulfides (LiPSs) into the pores, and provides favorable channels for ion diffusion. The rich nitrogen and carbon defects further offer more active sites for strongly adsorbing LiPSs and bridge electron transfer pathway at atomic scale for catalytic reactions to accelerate redox kinetics of Li/S conversion chemistry. Moreover, the features of lithiophilic wettability, high adsorption energy and densely distributed lithiophilic N of g-C3N4 provide a large number of adhesive sites for lithium cation (Li+) and disperse the nucleation sites to enable uniform nucleation and deposition of Li on the anode surface and to suppress formation and growth of Li dendrites. Finally, the g-C3N4 also effectively regulates the wettability between Li anode and solid inorganic electrolyte, and reduces the crystallinity of solid polymer electrolyte to enhance the Li+ migration ability and ionic conductivity.
Crystallinity-dependent device characteristics of polycrystalline 2D n = 4 Ruddlesden–Popper perovskite photodetectors
Authors: Kim Junwoo , Lee Woocheol , Cho Kyungjune , Ahn Heebeom , Lee Jonghoon , Baek Kyeong-Yoon , Kim Jae-Keun , Kang Keehoon , Lee Takhee
Published: January 2021

Ruddlesden–Popper (RP) perovskites have attracted a lot of attention as the active layer for optoelectronic devices due to their excellent photophysical properties and environmental stability. Especially, local structural properties of RP perovskites have shown to play important roles in determining the performance of optoelectronic devices. Here, we report the photodetector performance variation depending on the crystallinity of n = 4 two-dimensional (2D) RP perovskite polycrystalline films. Through controlling the solvent evaporation rate, 2D RP perovskite films could be tuned between highly- and randomly-orientated phases. We investigated how different factors related to the film crystallinity are reflected in the variation of photodetector performances by considering grain boundary and low energy edge state effects in n = 4 RP perovskites. Better understanding the interplay between these factors that govern the photophysical properties of the devices would be beneficial for designing high-performance RP perovskite-based optoelectronic devices.
H2S sensing for breath analysis with Au functionalized ZnO nanowires
Authors: Kaiser Angelika , Torres Ceja Erick , Liu Yujia , Huber Florian , Müller Raphael , Herr Ulrich , Thonke Klaus
Published: January 2021

This work presents a H2S selective resistive gas sensor design based on a chemical field effect transistor (ChemFET) with open gate formed by hundreds of high temperature chemical vapour deposition (CVD) grown zinc oxide nanowires (ZnO NW). The sensing ability of pristine ZnO NWs and surface functionalized ZnO NWs for H2S is analysed systematically. ZnO NWs are functionalized by deposition of discontinuous gold (Au) nanoparticle films of different thicknesses of catalyst layer ranging from 1 to 10 nm and are compared in their gas sensing properties. All experiments were performed in a temperature stabilized small volume compartment with adjustable gas mixture at room temperature. The results allow for a well-founded understanding of signal-to-noise ratio, enhanced response, and improved limit of detection due to the Au functionalisation. Comprehension and controlled application of the beneficial effects of Au catalyst on ZnO NWs allow for the detection of very low H2S concentrations down to 10 ppb, and a theoretically estimated 500 ppt in synthetic air at room temperature.
Quantitative estimation of atom-scaled ripple structure using transmission electron microscopy images
Authors: Xie Lilin , Oshima Yoshifumi
Published: January 2021

Atom-scaled ripple structure can be intrinsically formed because of thermal instability or induced stress in graphene or two-dimensional (2D) materials. However, it is difficult to estimate the period, amplitude, and shape of such a ripple structure. In this study, by applying the geometrical phase analysis method to atomically resolved transmission electron microscopy images, we demonstrate that the atom-scaled ripple structure of MoS2 nanosheet can be quantitatively analyzed at the subnanometer scale. Furthermore, by analyzing the observed ripple structure of the MoS2 nanosheet, we established that it is inclined by approximately 7.1° from the plane perpendicular to the incident electron beam; it had 5.5 and 0.3 nm in period and amplitude, respectively. For quantitative estimation of ripple structure, our results provide an effective method that contributes to a better understanding of 2D materials in the sub-nanometre scale.
An oblique projection modification technique (OPMT) for fast multispectral CT reconstruction
Authors: Zhao Shusen , Pan Huiying , Zhang Weibin , Xia Dimeng , Zhao Xing
Published: January 2021

In x-ray multispectral (or photon-counting) computed tomography (MCT), the object of interest is scanned under multiple x-ray spectra, and it can acquire more information about the scanned object than conventional CT, in which only one x-ray spectrum is used. The obtained polychromatic projections are utilized to perform material-selective and energy-selective image reconstruction. Compared with the conventional single spectral CT, MCT has a superior material distinguishability. Therefore, it has wide potential applications in both medical and industrial areas. However, the nonlinearity and ill condition of the MCT problem make it difficult to get high-quality and fast convergence of images for existing MCT reconstruction algorithms. In this paper, we proposed an iterative reconstruction algorithm based on an oblique projection modification technique (OPMT) for fast basis material decomposition of MCT. In the case of geometric inconsistency, along the current x-ray path, the oblique projection modification direction not only relates to the polychromatic projection equation of the known spectrum, but it also comprehensively refers to the polychromatic projection equation information of the unknown spectra. Moreover, the ray-by-ray correction makes it applicable to geometrically consistent projection data. One feature of the proposed algorithm is its fast convergence speed. The OPMT considers the information from multiple polychromatic projection equations, which greatly speeds up the convergence of MCT reconstructed images. Another feature of the proposed algorithm is its high flexibility. The ray-by-ray correction will be suitable for any common MCT scanning mode. The proposed algorithm is validated with numerical experiments from both simulated and real data. Compared with the ASD-NC-POCS and E-ART algorithms, the proposed algorithm achieved high-quality reconstructed images while accelerating the convergence speed of them.
New target volume delineation and PTV strategies to further personalise radiotherapy
Authors: Bernstein David , Taylor Alexandra , Nill Simeon , Oelfke Uwe
Published: January 2021

Target volume delineation uncertainty (DU) is arguably one of the largest geometric uncertainties in radiotherapy that are accounted for using planning target volume (PTV) margins. Geometrical uncertainties are typically derived from a limited sample of patients. Consequently, the resultant margins are not tailored to individual patients. Furthermore, standard PTVs cannot account for arbitrary anisotropic extensions of the target volume originating from DU. We address these limitations by developing a method to measure DU for each patient by a single clinician. This information is then used to produce PTVs that account for each patient’s unique DU, including any required anisotropic component. We do so using a two-step uncertainty evaluation strategy that does not rely on multiple samples of data to capture the DU of a patient’s gross tumour volume (GTV) or clinical target volume. For simplicity, we will just refer to the GTV in the following. First, the clinician delineates two contour sets; one which bounds all voxels believed to have a probability of belonging to the GTV of 1, while the second includes all voxels with a probability greater than 0. Next, one specifies a probability density function for the true GTV boundary position within the boundaries of the two contours. Finally, a patient-specific PTV, designed to account for all systematic errors, is created using this information along with measurements of the other systematic errors. Clinical examples indicate that our margin strategy can produce significantly smaller PTVs than the van Herk margin recipe. Our new radiotherapy target delineation concept allows DUs to be quantified by the clinician for each patient, leading to PTV margins that are tailored to each unique patient, thus paving the way to a greater personalisation of radiotherapy.