bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of metabolomics and transcriptomics data to further characterize Gliricidia sepium (Jacq.) Kunth under high salinity stress
Authors: Carvalho da Silva Thalliton Luiz , Belo Silva Vivianny Nayse , Braga Ítalo de Oliveira , Rodrigues Neto Jorge Candido , Leão André Pereira , Ribeiro José Antônio de Aquino , Valadares Leonardo Fonseca , Abdelnur Patrícia Verardi , de Sousa Carlos Antônio Ferreira , Souza Manoel Teixeira
Published: December 2021

Soil salinity is one abiotic stress that threatens agriculture in more than 100 countries. Gliricidia [Gliricidia sepium (Jacq.) Kunth] is a multipurpose tree known for its ability to adapt to a wide range of soils; however, its tolerance limits and responses to salt stress are not yet well understood. In this study, after characterizing the morphophysiological responses of young gliricidia plants to salinity stress, leaf metabolic and transcription profiles were generated and submitted to single and integrated analyses. RNA from leaf samples were subjected to RNA sequencing using an Illumina HiSeq platform and the paired‐end strategy. Polar and lipidic fractions from leaf samples were extracted and analyzed on an ultra‐high‐performance liquid chromatography (UHPLC) coupled with electrospray ionization quadrupole time‐of‐flight high‐resolution mass spectrometry (MS) system. Acquired data were analyzed using the OmicsBox, XCMS Online, MetaboAnalyst, and Omics Fusion platforms. The substrate salinization protocol used allowed the identification of two distinct responses to salt stress: tolerance and adaptation. Single analysis on transcriptome and metabolome data sets led to a group of 5,672 transcripts and 107 metabolites differentially expressed in gliricidia leaves under salt stress. The phenylpropanoid biosynthesis was the most affected pathway, with 15 metabolites and three genes differentially expressed. Results showed that the differentially expressed metabolites and genes from this pathway affect mainly short‐term salt stress (STS). The single analysis of the transcriptome identified 12 genes coding for proteins that might play a role in gliricidia response at both STS and long‐term salt stress (LTS). Further studies are needed to reveal the mechanisms behind the adaptation response.
Phase transitions in tensorial group field theories: Landau-Ginzburg analysis of models with both local and non-local degrees of freedom
Authors: Marchetti Luca , Oriti Daniele , Pithis Andreas G. A. , Thürigen Johannes
Published: December 2021

Abstract

In the tensorial group field theory approach to quantum gravity, the theory is based on discrete building blocks and continuum spacetime is expected to emerge from their collective dynamics, possibly at criticality, via a phase transition. On a compact group of fixed volume this can be expected to be only possible in a large-volume or thermodynamic limit. Here we show how phase transitions are possible in TGFTs in two cases: a) considering the non-local group degrees of freedom on a non-compact Lie group instead of a compact one (or taking a large-volume limit of a compact group); b) in models including ℝ-valued local degrees of freedom (that can be interpreted as discrete scalar fields, often used in this context to provide a matter reference frame). After adapting the Landau-Ginzburg approach to this setting of mixed local/non-local degrees of freedom, we determine the critical dimension beyond which there is a Gaussian fixed point and a continuous phase transition which can be described by mean-field theory. This is an important step towards the realization of a phase transition to continuum spacetime in realistic TGFT models for quantum gravity.
Estimates for Operators Related to the Sub-Laplacian with Drift in Heisenberg Groups
Authors: Li Hong-Quan , Sjögren Peter
Published: December 2021

In the Heisenberg group of dimension $$2n+1$$

2
n
+
1

, we consider the sub-Laplacian with a drift in the horizontal coordinates. There is a related measure for which this operator is symmetric. The corresponding Riesz transforms are known to be $$L^p$$

L
p

bounded with respect to this measure. We prove that the Riesz transforms of order 1 are also of weak type (1, 1), and that this is false for order 3 and above. Further, we consider the related maximal Littlewood–Paley–Stein operators and prove the weak type (1, 1) for those of order 1 and disprove it for higher orders.
Inversion of the transverse force on a spinning sphere moving in a rarefied gas
Authors: Taguchi Satoshi , Tsuji Tetsuro
Published: December 2021

The flow around a spinning sphere moving in a rarefied gas is considered in the following situation: (i) the translational velocity of the sphere is small (i.e. the Mach number is small); (ii) the Knudsen number, the ratio of the molecular mean free path to the sphere radius, is of the order of unity (the case with small Knudsen numbers is also discussed); and (iii) the ratio between the equatorial surface velocity and the translational velocity of the sphere is of the order of unity. The behaviour of the gas, particularly the transverse force acting on the sphere, is investigated through an asymptotic analysis of the Boltzmann equation for small Mach numbers. It is shown that the transverse force is expressed as

$\boldsymbol{F}_L = {\rm \pi}\rho a^3 (\boldsymbol{\varOmega} \times \boldsymbol{v}) \bar{h}_L$

, where

$\rho$

is the density of the surrounding gas, a is the radius of the sphere,

$\boldsymbol {\varOmega }$

is its angular velocity,

$\boldsymbol {v}$

is its velocity and

$\bar {h}_L$

is a numerical factor that depends on the Knudsen number. Then,

$\bar {h}_L$

is obtained numerically based on the Bhatnagar–Gross–Krook model of the Boltzmann equation for a wide range of Knudsen number. It is shown that

$\bar {h}_L$

varies with the Knudsen number monotonically from 1 (the continuum limit) to

$-\tfrac {2}{3}$

(the free molecular limit), vanishing at an intermediate Knudsen number. The present analysis is intended to clarify the transition of the transverse force, which is previously known to have different signs in the continuum and the free molecular limits.
Sound generation mechanism of compressible vortex reconnection
Authors: Daryan Hamid , Hussain Fazle , Hickey Jean-Pierre
Published: December 2021

We study the sound generation mechanism of initially subsonic viscous vortex reconnection at vortex Reynolds number

$Re~(\equiv \text {circulation}/\text {kinematic viscosity})=1500$

through decomposition of Lighthill's acoustic source term. The Laplacian of the kinetic energy, flexion product, enstrophy and deviation from the isentropic condition provide the dominant contributions to the acoustic source term. The overall (all time) extrema of the total source term and its dominant hydrodynamic components scale linearly with the reference Mach number

$M_o$

; the deviation from the isentropic condition shows a quadratic scaling. The significant sound arising from the flexion product occurs due to the coiling and uncoiling of the twisted vortex filaments wrapping around the bridges, when a rapid strain is induced on the filaments by the repulsion of the bridges. The spatial distributions of the various acoustic source terms reveal the importance of mutual cancellations among most of the terms; this also highlights the importance of symmetry breaking in the sound generation during reconnection. Compressibility acts to delay the start of the sequence of reconnection events, as long as shocklets, if formed, are sufficiently weak to not affect the reconnection. The delayed onset has direct ramifications for the sound generation by enhancing the velocity of the entrained jet between the vortices and increasing the spatial gradients of the acoustic source terms. Consistent with the near-field pressure, the overall maximum instantaneous sound pressure level in the far field has a quadratic dependence on

$M_o$

. Thus, reconnection becomes an even more dominant sound-generating event at higher

$M_o$

.
Tracking consumption at Pompeii: the graffiti lists
Authors: Bowes Kim
Published: December 2021

This paper examines five graffiti expense lists from Pompeii for information on the habits of consumption in the Vesuvian cities. It is intended as a contribution to the growing literature on economic well-being in Pompeii, focusing on the diet and consumption strategies of the nonelite Roman majority. These lists provide rare quantitative evidence for a portion of a whole diet, as well as nonfood expenses. They also shed light on the place of cereals in the overall Vesuvian diet, the importance of consumer goods, and cycles of plenty and want.
Anti-ELAB Movement, National Security Law, and heterogeneous institutional trust in Hong Kong
Authors: Tung Hans H. , Lin Ming-Jen , Lin Yi-Fan
Published: December 2021

How does repression on opposition protests affect citizens' institutional trust under dictatorships? There has been a burgeoning literature investigating empirically both long- and short-term impacts of protests and their repression on citizens' political preferences in both democratic and nondemocratic contexts. Yet, the literature tells us relatively little about how the above question could be answered. This paper tries to answer this question by taking advantage of a recent natural experiment in Hong Kong when Beijing suddenly adopted the National Security Law (NSL) in June 2020 to repress dissidents' protest mobilization. Our findings are twofold. First of all, the NSL drove a wedge in the Hong Kong society by making the pro-establishment camp more satisfied with the post-NSL institutions on the one hand, while alienating the pro-democracy camp who lost tremendous trust in them on the other. Second, our study also reveals that one's trust in institutions is significantly associated with the regimes' ability to curb protesters' contentious mobilization. The Hong Kongers who had higher confidence in the NSL to rein in protests would also have a greater level of trust than those who didn't. The effect, however, is substantially smaller among pro-democracy Hong Kongers except for their trust in monitoring institutions. As Beijing is transforming Hong Kong's current institutions from within hopes of bringing about a new political equilibrium, our study helps provide a timely assessment of Hong Kong's institutional landscape and sheds light on how likely this strategy can work.
Implications of Increasing Household Air Conditioning Use Across the United States Under a Warming Climate
Authors: Obringer Renee , Nateghi Roshanak , Maia‐Silva Debora , Mukherjee Sayanti , CR Vineeth , McRoberts Douglas Brent , Kumar Rohini
Published: December 2021

Soaring temperatures and increased occurrence of heatwaves have drastically increased air‐conditioning demand, a trend that will likely continue into the future. Yet, the impact of anthropogenic warming on household air conditioning is largely unaccounted for in the operation and planning of energy grids. Here, by leveraging the state‐of‐the‐art in machine learning and climate model projections, we find substantial increases in future residential air conditioning demand across the U.S.—up to 8% with a range of 5%–8.5% (13% with a range of 11%–15%) after anthropogenic warming of 1.5°C (2.0°C) in global mean temperature. To offset this climate‐induced demand, an increase in the efficiency of air conditioners by as much as 8% (±4.5%) compared to current levels is needed; without this daunting technological effort, we estimate that some states will face supply inadequacies of up to 75 million “household‐days” (i.e., nearly half a month per average current household) without air conditioning in a 2.0°C warmer world. In the absence of effective climate mitigation and technological adaptation strategies, the U.S. will face substantial increases in air conditioning demand and, in the event of supply inadequacies, there is increased risk of leaving millions without access to space cooling during extreme temperatures.
Analysis of Long‐Term GIC Measurements in Transformers in Austria
Authors: Albert D. , Schachinger P. , Bailey R. L. , Renner H. , Achleitner G.
Published: December 2021

Geomagnetically induced currents (GICs), a result of solar wind interaction with the Earth's magnetic field and the resistive ground, are known to flow in power transmission grids, where they can lead to transformer damage and grid operation problems. In this study we present an analysis of five years of continuous GIC measurements in transformer neutral points in Austria. Seven self‐designed stand‐alone measurement systems are currently installed in the Austrian 220 and 380 kV transmission levels, measuring currents up to 25 A. We identify recurrent geomagnetic activity in the measurements, and also find man‐made sources of low frequency currents using frequency analysis. In order to support the transmission grid operators, two GIC simulation approaches are used to simulate GICs in the power grid. The first model uses measurements to derive the sensitivity of the location to northward and eastward geoelectric field components (which requires no detailed grid data), and the second model uses the detailed grid model to compute GICs from a geoelectric field. We evaluate two geomagnetic storms from September 2017 and May 2021 to discuss the effects of GICs on the power transmission grid and its assets.
Metal ion modulation triggers dielectric double switching and green fluorescence in A2MX4-type compounds
Authors: Shao Ting , Ren Rui-Ying , Huang Pei-Zhi , Ni Hao-Fei , Su Chang-Yuan , Fu Da-Wei , Xie Li-Yan , Lu Hai-Feng
Published: December 2021

Multifunctional switching materials show great potential for applications in sensors, smart switches, and other fields due to their ability to integrate different physical channels in one single device.
Recent developments of hydrogel based solar water purification technology
Authors: Mao Shudi , Johir Md Abu Hasan , Onggowarsito Casey , Feng An , Nghiem Long D. , Fu Qiang
Published: December 2021

Hydrogel-based solar water purification technology has been recognized as a promising alternative to existing energy-intensive technologies. This is a timely review of the recent 3 years, focusing on design principles and remaining challenges.
Molecular engineering of ruthenium-based photosensitizers with superior photovoltaic performance in DSSCs: novel N-alkyl 2-phenylindole-based ancillary ligands
Authors: Ashraf Saba , Su Rui , Akhtar Javeed , Shuja Ahmed , Siddiqi Humaira M. , El-Shafei Ahmed
Published: December 2021

In this work, we report the design and successful synthesis of two new heteroleptic polypyridyl Ru(ii) complexes (SD-5 and SD-6), by incorporating hetero-aromatic electron-donating N-alkyl-2-phenylindole moieties into the ancillary ligand.
A squaramide-catalysed asymmetric cascade Michael addition/acyl transfer reaction between unsaturated benzothiophenones and α-nitroketones
Authors: Niu Cheng , Du Da-Ming
Published: December 2021

A practical organocatalytic asymmetric synthesis of chiral acyloxybenzothiophene derivatives was developed using unsaturated benzothiophenones and α-nitroketones catalysed by squaramide via Michael addition/acyl transfer cascade reactions.
Overcoming energy loss of thermally activated delayed fluorescence sensitized-OLEDs by developing a fluorescent dopant with a small singlet–triplet energy splitting
Authors: Wang Xinye , Zhang Yifan , Yu Ze , Wu Yuan , Wang Dongdong , Wu Chuanming , Ma Huili , Ning Shuya , Dong Hua , Wu Zhaoxin
Published: December 2021

An approach was presented to suppress T1-state energy loss in OLEDs. That is developing comparable T1-energy FD with TADF co-host, and thus, T1 excitons on the FDs would escape and go back to the co-host and then transfer to the singlet state of the FDs, finally contributing to light-emission.
Magnetorotational instability with smoothed particle hydrodynamics
Authors: Wissing Robert , Shen Sijing , Wadsley James , Quinn Thomas
Published: December 2021

The magnetorotational instability (MRI) is an important process in driving turbulence in sufficiently ionized accretion disks. It has been extensively studied using simulations with Eulerian grid codes, but remains fairly unexplored for meshless codes. Here, we present a thorough numerical study on the MRI using the smoothed particle magnetohydrodynamics method with the geometric density average force expression. We performed 37 shearing box simulations with different initial setups and a wide range of resolution and dissipation parameters. We show, for the first time, that MRI with sustained turbulence can be simulated successfully with smoothed-particle hydrodynamics (SPH), with results consistent with prior work with grid-based codes, including saturation properties such as magnetic and kinetic energies and their respective stresses. In particular, for the stratified boxes, our simulations reproduce the characteristic “butterfly” diagram of the MRI dynamo with saturated turbulence for at least 100 orbits. On the contrary, traditional SPH simulations suffer from runaway growth and develop unphysically large azimuthal fields, similar to the results from a recent study with meshless methods. We investigated the dependency of MRI turbulence on the numerical Prandtl number (Pm) in SPH, focusing on the unstratified, zero net-flux case. We found that turbulence can only be sustained with a Prandtl number larger than ∼2.5, similar to the critical values for the physical Prandtl number found in grid-code simulations. However, unlike grid-based codes, the numerical Prandtl number in SPH increases with resolution, and for a fixed Prandtl number, the resulting magnetic energy and stresses are independent of resolution. Mean-field analyses were performed on all simulations, and the resulting transport coefficients indicate noα-effect in the unstratified cases, but an activeαωdynamo and a diamagnetic pumping effect in the stratified medium, which are generally in agreement with previous studies. There is no clear indication of a shear-current dynamo in our simulation, which is likely to be responsible for a weaker mean-field growth in the tall, unstratified, zero net-flux simulation.
The Great Aurora of 4 February 1872 observed by Angelo Secchi in Rome
Authors: Berrilli Francesco , Giovannelli Luca
Published: December 2021

Observation of auroras at low latitudes is an extremely rare event typically associated with major magnetic storms due to intense Earth-directed Coronal Mass Ejections. Since these energetic events represent one of the most important components of space weather, their study is of paramount importance to understand the Sun-Earth connection. Due to the rarity of these events, being able to access all available information for the few cases studied is equally important. Especially if we refer to historical periods in which current accurate observations from ground-based instruments or space were not available. Certainly, among these events, we must include the great aurora of February 4, 1872. An event whose effects have been observed in different regions of the Earth. What we could consider today a global event, especially for its effects on the communication systems of the time, such as the transatlantic cable that allowed a connection between the United States and Europe since 1866. In this paper, we describe the main results of the observations and studies carried out by Angelo Secchi at the Observatory of the Roman College and described in hisMemoria sull’Aurora Elettrica del 4 Febbraio 1872for the Notes of the Pontifical Academy of new Lincei. This note is extremely modern both in its multi-instrumental approach to the study of these phenomena and in its association between solar-terrestrial connection and technological infrastructures on the Earth. The Secchi’s note definitely represents the first example of analysis and study of an event on a global scale, such as the Atlantic cable, affecting the Earth. What we nowadays call an extreme space weather event.
Natural Prenylated Xanthones as Potential Inhibitors of PI3k/Akt/mTOR Pathway in Triple Negative Breast Cancer Cells
Authors: Nguyen Thi Thu Ha , Qu Zhao , Nguyen Van Tuyen , Nguyen Thanh Tra , Le Thi Tu Anh , Chen Sibao , Ninh Son The
Published: December 2021

Three prenylated xanthones, garcinone E (1), bannaxanthone D (2) and bannanxanthone E (3) were isolated from the leaves of Garcinia mckeaniana Graib. Their structures were elucidated by spectral methods and compared with literature data. To evaluate their anti-proliferative effects in tumor cells, firstly, cisplatin was used as a positive control and the effects of compound 1 – 3 were determined by performing MTT assay in MDA-MB-231, CNE-2 and A549 cancer cells. The results showed compound 1 – 3 exhibited stronger inhibitory effect than cisplatin in MDA-MB-231. Further effects of compound 1 – 3 in TNBC MDA-MB-231 and MDA-MB-468 cells were examined by performing cell cycle and apoptosis assays. The results indicated that compound 1 – 3 had ability to arrest cell cycle at G2/M phase and induce apoptosis. Furthermore, compound 2 significantly down-regulated PI3K, Akt and mTOR levels in both total proteins and phosphorylated form, which is its potential anti-cancer mechanism. These findings indicated that those prenylated xanthones might serve as promising leading compounds for the development of anticancer drug for TNBC.
A Data-Driven Iterative Approach for Semi-automatically Assessing the Correctness of Medication Value Sets: A Proof of Concept Based on Opioids
Authors: Li Linyi , Grando Adela , Sarker Abeed
Published: December 2021

Background Value sets are lists of terms (e.g., opioid medication names) and their corresponding codes from standard clinical vocabularies (e.g., RxNorm) created with the intent of supporting health information exchange and research. Value sets are manually-created and often exhibit errors.

Objectives The aim of the study is to develop a semi-automatic, data-centric natural language processing (NLP) method to assess medication-related value set correctness and evaluate it on a set of opioid medication value sets.

Methods We developed an NLP algorithm that utilizes value sets containing mostly true positives and true negatives to learn lexical patterns associated with the true positives, and then employs these patterns to identify potential errors in unseen value sets. We evaluated the algorithm on a set of opioid medication value sets, using the recall, precision and F1-score metrics. We applied the trained model to assess the correctness of unseen opioid value sets based on recall. To replicate the application of the algorithm in real-world settings, a domain expert manually conducted error analysis to identify potential system and value set errors.

Results Thirty-eight value sets were retrieved from the Value Set Authority Center, and six (two opioid, four non-opioid) were used to develop and evaluate the system. Average precision, recall, and F1-score were 0.932, 0.904, and 0.909, respectively on uncorrected value sets; and 0.958, 0.953, and 0.953, respectively after manual correction of the same value sets. On 20 unseen opioid value sets, the algorithm obtained average recall of 0.89. Error analyses revealed that the main sources of system misclassifications were differences in how opioids were coded in the value sets—while the training value sets had generic names mostly, some of the unseen value sets had new trade names and ingredients.

Conclusion The proposed approach is data-centric, reusable, customizable, and not resource intensive. It may help domain experts to easily validate value sets.
Effects of Modified Osteoplastic Pterional Craniotomy on Temporal Muscle Volume and Frontal Muscle Nerve Function
Authors: Seçer Mehmet , Çam İsa , Gökbel Aykut , Ulutaş Murat , Çakır Özgür , Ergen Anıl , Çınar Kadir
Published: December 2021

Introduction Pterional craniotomy is a surgical approach frequently used in aneurysm and skull base surgery. Pterional craniotomy may lead to cosmetic and functional problems, such as eyebrow drop due to facial nerve frontal branch damage, temporal muscle atrophy, and temporomandibular joint pain. The aim was to compare the postoperative effects of our modified osteoplastic craniotomy with classical pterional craniotomy in terms of any change in volume of temporal muscle and in the degree of frontal muscle nerve damage.

Materials and Methods Aneurysm cases were operated with either modified osteoplastic pterional craniotomy or free bone flap pterional craniotomy according to the surgeon's preference. Outcomes were compared in terms of temporal muscle volume and frontal muscle nerve function 6 months postoperatively.

Results Preoperative temporal muscle volume in the modified osteoplastic pterional and free bone flap pterional craniotomy groups were not different (p > 0.05). However, significantly less atrophy was observed in the postoperative temporal muscle volume of the osteoplastic group compared with the classical craniotomy group (p < 0.001). In addition, when comparing frontal muscle nerve function there was less nerve damage in the modified osteoplastic pterional craniotomy group compared with the classical craniotomy group, although this did not reach significance (p > 0.05).

Conclusion Modified osteoplastic pterional craniotomy significantly reduced atrophy of temporal muscle and caused proportionally less frontal muscle nerve damage compared with pterional craniotomy, although this latter outcome was not significant. These findings suggest that osteoplastic craniotomy may be a more advantageous intervention in cosmetic and functional terms compared with classical pterional craniotomy.
Volumetric Resection and Complications in Nonfunctioning Pituitary Adenoma by Fully Endoscopic Transsphenoidal Approach along 15 Years of Single-Center Experience
Authors: Palpan Flores Alexis , Sáez Alegre Miguel , Vivancos Sanchez Catalina , Pérez Alvaro Zamarrón , Pérez-López Carlos
Published: December 2021

Objective The aim of this study was to evaluate the rate of complications and the extent of resection (EOR) of nonfunctioning pituitary adenomas by endoscopic endonasal approach (EEA) in a 15-year learning curve.

Methods A total of 100 patients operated by the same surgical team were divided chronologically into two, three, and four groups, comparing differences in EOR measured by a semiautomatic software (Smartbrush, Brainlab), rate of immediate postoperative complications, and the visual and hormonal status at 6 months.

Results There were no significant differences over the years in rates of postoperative complications and in visual status at 6 months. A significant linear correlation between the EOR and the number of surgeries (rho = 0.259, p = 0.007) was found. The analysis was performed in three groups because of the remarkable differences among them; the EOR were: 87.2% (early group), 93.03% (intermediate group), and 95.1% (late group) (p = 0.019). Gross total resection was achieved in 30.3, 51.5, and 64%, respectively (p = 0.017); also, the rate of reoperation and the worsening of at least one new hormonal axis were worse in the early group. Consequently, the early group had a higher risk of incomplete resection compared with the late group (odds ratio: 4.2; 95% confidence interval: 1.5–11.7). The three groups were not different in demographic and volume tumor variables preoperatively.

Conclusions The first 33 interventions were associated with a lower EOR, a high volume of residual tumor, a high reoperation rate, and a higher rate of hormonal dysfunction. We did not find differences in terms of postoperative complications and the visual status at 6-month follow-up.
Temperature-dependent local conformations and conformational distributions of cyanine dimer labeled single-stranded–double-stranded DNA junctions by 2D fluorescence spectroscopy
Authors: Heussman Dylan , Kittell Justin , von Hippel Peter H. , Marcus Andrew H.
Published: December 2021

DNA replication and the related processes of genome expression require binding, assembly, and function of protein complexes at and near single-stranded (ss)–double-stranded (ds) DNA junctions. These central protein–DNA interactions are likely influenced by thermally induced conformational fluctuations of the DNA scaffold across an unknown distribution of functionally relevant states to provide regulatory proteins access to properly conformed DNA binding sites. Thus, characterizing the nature of conformational fluctuations and the associated structural disorder at ss–dsDNA junctions is critical for understanding the molecular mechanisms of these central biological processes. Here, we describe spectroscopic studies of model ss–dsDNA fork constructs that contain dimers of “internally labeled” cyanine (iCy3) chromophore probes that have been rigidly inserted within the sugar–phosphate backbones of the DNA strands. Our combined analyses of absorbance, circular dichroism, and two-dimensional fluorescence spectroscopy permit us to characterize the local conformational parameters and conformational distributions. We find that the DNA sugar–phosphate backbones undergo abrupt successive changes in their local conformations—initially from a right-handed and ordered DNA state to a disordered splayed-open structure and then to a disordered left-handed conformation—as the dimer probes are moved across the ss–dsDNA junction. Our results suggest that the sugar–phosphate backbones at and near ss–dsDNA junctions adopt specific position-dependent local conformations and exhibit varying extents of conformational disorder that deviate widely from the Watson–Crick structure. We suggest that some of these conformations can function as secondary-structure motifs for interaction with protein complexes that bind to and assemble at these sites.
Optical Coherence Elastography Imaging Probes
Authors: Sanderson Rowan W. , Fang Qi , Curatolo Andrea , Kennedy Brendan F.
Published: December 2021

Imaging probes for optical coherence elastography (OCE) are undergoing development to enable its practical implementation in a number of applications. The specific challenges posed by each application defines the technical requirements for each probe, leading to the development of a range of benchtop, handheld and endoscopic probes. In addition, a number of more compact OCE imaging probes have been proposed, including finger-mounted and needle-based probes. In this chapter, we describe each of these probes in detail within the context of the relevant applications they are proposed for. An analysis of each probe is provided, with particular focus on optical design, mechanical loading, and image acquisition protocol.
Bearing fault diagnosis using a speed-adaptive network based on vibro-speed data fusion and majority voting
Authors: Yuan Zonghao , Ma Zengqiang , Li Xin , Gao Dayong , Fu Zhipeng
Published: December 2021

Fault diagnosis of rolling bearings is key to maintain and repair modern rotating machinery. Rolling bearings are usually working in non-stationary conditions with time-varying loads and speeds. Existing diagnosis methods based on vibration signals only do not have the ability to adapt to rotational speed. And when the load changes, their accuracy rate will be obviously reduced. A method is put forward which fuses multi-modal sensor signals to fit speed information. Firstly, the features are extracted from raw vibration signals and instantaneous rotating speed signals, and fused by 1D-convolution neural network-based networks. Secondly, to improve the robustness of the model when the load changes, a majority voting mechanism is proposed in the diagnosis stage. Lastly, multiple variable speed samples of four bearings under three loads are obtained to evaluate the performance of the proposed method by analyzing the loss function, accuracy rate and F
1 score under different variable speed samples. It is empirically found that the proposed method achieves higher diagnostic accuracy and speed-adaptive ability than the algorithms based on vibration signal only. Moreover, a couple of ablation studies are also conducted to investigate the inner mechanism of the proposed speed-adaptive network.
Vision-based measurement for decoupling identification of geometric errors of rotating axes for five-axis platform
Authors: Yin Song , Zhou Haibo , Ju Xia , Li Zhiqiang
Published: December 2021

In this paper, a method for identifying and decoupling geometric errors of rotation axes using vision measurement is proposed. Based on screw theory and exponential product formula, identification equations of position-dependent geometric errors (PDGEs) and position-independent geometric errors (PIGEs) of the rotation axes are established. The mapping relationships between the error twist and geometric errors are established. The error model provides the coupling mechanism of PDGEs and PIGEs. Furthermore, a progressive decoupling method is proposed to separate PDGEs and PIGEs without additional assumptions. The pose parameters, required for solving the identification equations, are obtained by visual measurement. Then, the error terms of PIGEs and PDGEs are determined. Lastly, the error calibration of the rotation axes is investigated, thus providing an average rotary table orientation error reduction of 28.1% compared to the situation before calibration.
Applications of machine learning in computational nanotechnology
Authors: Liu Wenxiang , Wu Yongqiang , Hong Yang , Zhang Zhongtao , Yue Yanan , Zhang Jingchao
Published: December 2021

Machine learning (ML) has gained extensive attention in recent years due to its powerful data analysis capabilities. It has been successfully applied to many fields and helped the researchers to achieve several major theoretical and applied breakthroughs. Some of the notable applications in the field of computational nanotechnology are ML potentials, property prediction, and material discovery. This review summarizes the state-of-the-art research progress in these three fields. ML potentials bridge the efficiency versus accuracy gap between density functional calculations and classical molecular dynamics. For property predictions, ML provides a robust method that eliminates the need for repetitive calculations for different simulation setups. Material design and drug discovery assisted by ML greatly reduce the capital and time investment by orders of magnitude. In this perspective, several common ML potentials and ML models are first introduced. Using these state-of-the-art models, developments in property predictions and material discovery are overviewed. Finally, this paper was concluded with an outlook on future directions of data-driven research activities in computational nanotechnology.
The relationship between solid–liquid interface interaction and gelling capacity of h-BN 2D material: a rheological study
Authors: Zhang Ruochong , Cao Wenhui , Xia Yu , Zhang Haojie , Ding Qi , Xu Xuefeng , Hu Litian
Published: December 2021

Diurea modified h-BN nanosheet is a novel kind of 2D gelator that could gel the lubricating oils under the stimulus of ultrasound. Morphological analyzations in previous study confirmed that the ultrasound induced layer-by-layer (LBL) structure of BN gelator is critical for the gelation. However, the elastic response in LBL structure, which is crucial for the formation of a stable gel system, has not been explicitly illustrated yet. The challenge is that the LBL gelator structure is based on 2D material and thus lacks vertical linkage between gelator layers, which is significantly different from the traditional gel systems that generally possess highly crosslinked gelator network. In this work, by investigating the viscoelastic behavior of the BN-based gel via rheometer, it is found the solid–liquid interface interaction, which is regulated by the diurea molecular structure in the BN gelator, is the key factor for triggering the stable elastic response in the LBL structure, and the elasticity mainly originates from the interface interaction induced bending deformation of h-BN 2D material. The findings further elucidate the gelling mechanism of BN gelators and enlighten the structure design of ultrasound-responsive gelator based on 2D materials.
Prior knowledge of potential energy and the understanding of quantum mechanics
Authors: Krijtenburg-Lewerissa Kim , Pol Henk , Brinkman Alexander , van Joolingen Wouter
Published: December 2021

Quantum mechanics (QM) has become part of many secondary school curricula. These curricula often do not include the mathematical tools for a formal, mathematical introduction of QM. QM therefore needs to be taught at a more conceptual level, but making secondary school students understand counterintuitive QM concepts without introducing mathematical formalism is a challenge. In order to accept QM, students not only have to see the need of it, but also have to see that QM is understandable and logical. Dutch secondary school students are familiar with potential energy (PE) in the context of gravitational and elastic energy. Therefore, the introduction of QM by using the potential wells and tunneling with emphasis on students’ prior knowledge of PE could be a way to make QM more understandable and logical. To explore this, we investigated the relation between the understanding of energy diagrams and the understanding of the potential well and tunneling. A module was created to promote students’ understanding of PE in classical context. Then, a quasi-experimental intervention was used, in which the experimental group received additional lessons using the module on classical energy diagrams before being taught QM. Two tests were developed in order to determine students’ understanding of PE and QM. The results of the tests showed that the experimental group not only had better understanding of PE diagrams, but also of QM even before they were being taught QM. Analysis of the tests also showed that there was a significant correlation between the understanding of PE diagrams and the understanding of QM. Therefore, the results of this study indicate that emphasis on PE can be used to reduce the gap between students’ prior knowledge and QM.
We know the way: learning the secrets of celestial navigation from ancient travellers
Authors: Spathopoulos Vassilios McInnes
Published: December 2021

Educators are constantly looking for new ways to inspire students to actively engage with science. Learning how to navigate by using the stars, sun and moon can be one of the first steps for pupils, students and the general public to cultivate an interest in astronomy. With this in mind, an online platform based on the Google Earth and Stellarium software has been developed. It presents basic celestial navigation techniques that were first devised and deployed by the ancient Phoenicians and Greeks, the Vikings and the Polynesian travellers. Both software applications are free to use and are available in web versions, making them easily accessible to anyone with an internet connection. The user undertakes a set of predefined tasks that take him/her on a fascinating journey both around the world and back in time.
Spatial aspects of spin polarization of structurally split surface states in thin films with magnetic exchange and spin–orbit interaction
Authors: Nechaev I A , Krasovskii E E
Published: December 2021

A theoretical study is presented of the effect of an in-plane magnetic exchange field on the band structure of centrosymmetric films of noble metals and topological insulators. Based on an ab initio relativistic k ⋅ p theory, a minimal effective model is developed that describes two coupled copies of a Rashba or Dirac electronic system residing at the opposite surfaces of the film. The coupling leads to a structural gap at

Γ

¯

and causes an exotic redistribution of the spin density in the film when the exchange field is introduced. We apply the model to a nineteen-layer Au(111) film and to a five-quintuple-layer Sb2Te3 film. We demonstrate that at each film surface the exchange field induces spectrum distortions similar to those known for Rashba or Dirac surface states with an important difference due to the coupling: at some energies, one branch of the state loses its counterpart with the oppositely directed group velocity. This suggests that a large-angle electron scattering between the film surfaces through the interior of the film is dominant or even the only possible for such energies. The spin-density redistribution accompanying the loss of the counterpart favors this scattering channel.
Synchronization or cluster synchronization in coupled Van der Pol oscillators networks with different topological types
Authors: Shuai Wang , Yong Li
Published: December 2021

In this paper, we discuss the mechanism of synchronization or cluster synchronization in the coupled van der Pol oscillator networks with different topology types by using the theory of rotating periodic solutions. The synchronous solutions here are transformed into rotating periodic solutions of some dynamical systems. By analyzing the bifurcation of rotating periodic solutions, the critical conditions of synchronous solutions are given in three different networks. We use the rotating periodic matrix in the rotating periodic theory to judge various types of synchronization phenomena, such as complete synchronization, anti-phase synchronization, periodic synchronization, or cluster synchronization. All rotating periodic matrices which satisfy the exchange invariance of multiple oscillators form special groups in these networks. By using the conjugate classes of these groups, we obtain various possible synchronization solutions in three networks. In particular, we find symmetry has different effects on synchronization in different networks. The network with more types of symmetry has more elements in the corresponding group, which may have more types of synchronous solutions. However, different types of symmetry may get the same type of synchronous solutions or different types of synchronous solutions, depending on whether their corresponding rotating periodic matrices are similar.
High power supercontinuum generation by dual-color femtosecond laser pulses in fused silica
Authors: Zafar Saba , Li Dong-Wei , Camino Acner , Chang Jun-Wei , Hao Zuo-Qiang
Published: December 2021

High power supercontinuum (SC) is generated by focusing 800 nm and 400 nm femtosecond laser pulses in fused silica with a microlens array. It is found that the spectrum of the SC is getting broader compared with the case of a single laser pulse, and the spectral energy density between the two fundamental laser wavelengths is getting significantly higher by optimizing the phase matching angle of the BBO. It exceeds μJ/nm over 490 nm range which is from 380 nm to 870 nm, overcoming the disadvantage of relative lower power in the ranges far from the fundamental wavelength.
Exploring physical features of anisotropic quark stars in Brans-Dicke theory with a massive scalar field via embedding approach *
Authors: Errehymy Abdelghani , Mustafa G. , Khedif Youssef , Daoud Mohammed
Published: December 2021

The main aim of this study is to explore the existence and salient features of spherically symmetric relativistic quark stars in the background of massive Brans-Dicke gravity. The exact solutions to the modified Einstein field equations are derived for specific forms of coupling and scalar field functions using the equation of state relating to the strange quark matter that stimulates the phenomenological MIT-Bag model as a free Fermi gas of quarks. We use a well-behaved function along with the Karmarkar condition for class-one embedding as well as junction conditions to determine the unknown metric tensors. The radii of strange compact stars viz., PSR J1416-2230, PSR J1903+327, 4U 1820-30, CenX-3, and EXO1785-248, are predicted via their observed mass for different values of the massive Brans-Dicke parameters. We explore the influences of the mass of scalar field

, coupling parameter

, and bag constant

on state determinants and perform several tests on the viability and stability of the constructed stellar model. Conclusively, we find that our stellar system is physically viable and stable as it satisfies all the energy conditions and necessary stability criteria under the influence of a gravitational scalar field.
Investigation of the relation between space-weather parameters and Forbush decreases automatically selected from Moscow and Apatity cosmic ray stations during solar cycle 23
Authors: Alhassan Jibrin Adejoh , Okike Ogbonnaya , Chukwude Augustine Ejikeme
Published: December 2021

We present the results of an investigation of the relation between space-weather parameters and cosmic ray (CR) intensity modulation using algorithm-selected Forbush decreases (FDs) from Moscow (MOSC) and Apatity (APTY) neutron monitor (NM) stations during solar cycle 23. Our FD location program detected 408 and 383 FDs from MOSC and APTY NM stations respectively. A coincident computer code employed in this work detected 229 FDs that were observed at the same Universal Time (UT) at the two stations. Out of the 229 simultaneous FDs, we formed a subset of 139 large FDs(%) ≤ − 4 at the MOSC station. We performed a two-dimensional regression analysis between the FD magnitudes and the space-weather data on the two samples. We find that there were significant space-weather disturbances at the time of the CR flux depressions. The correlation between the space-weather parameters and decreases in galactic cosmic ray (GCR) intensity at the two NM stations is statistically significant. The implications of the present space-weather data on CR intensity depressions are highlighted.
Simulation analysis of a method to improve data-transmission performance of Nanshan 26m Radio Telescope based on Software-Defined Networks
Authors: Wang Jie , Zhang Hai-Long , Wang Na , Ye Xin-Chen , Wang Wan-Qiong , Li Jia , Zhang Meng , Zhang Ya-Zhou
Published: December 2021

Data Center of Xinjiang Astronomical Observatory (XAO-DC) commenced operating in 2015, and provides services including archiving, releasing and retrieving precious astronomical data collected by the Nanshan 26m Radio Telescope (NSRT) over the years, and realises the open sharing of astronomical observation data. The observation data from NSRT are transmitted to XAO-DC 100 km away through dedicated fiber for long-term storage. With the continuous increase of data, the static architecture of the current network cannot meet NSRT data-transmission requirements due to limited network bandwidth. To get high-speed data-transmission using the existing static network architecture, a method for reconstruction data-transmission network using Software-Defined Networks (SDN) is proposed. Benefit from the SDNʼs data and control plane separation, and open programmable, combined with the Mininet simulation platform for experiments, the TCP throughput (of single thread) was improved by ∼24.7%, the TCP throughput (of multi threads) was improved by ∼9.8%, ∼40.9%, ∼35.5% and ∼11.7%. Compared with the current network architecture, the Latency was reduced by ∼63.2%.
LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N): subtraction of geocoronal Hα emission
Authors: Zhang Wei , Wu Hong , Wu Chao-Jian , Ren Juan-Juan , Chen Jian-Hun , Hsia Chih-Hao , Wu Yu-Zhong , Zhu Hui , Shi Jian-Rong , Bai Zhong-Rui , Qi Zhao-Xiang , Zhao Yong-Heng , Hou Yong-Hui
Published: December 2021

We introduce a method of subtracting geocoronal Hα emissions from the spectra of LAMOST medium-resolution spectral survey of Galactic nebulae (LAMOST-MRS-N). The flux ratios of the Hα sky line to the adjacent OH λ6554 single line do not show a pattern or gradient distribution in a plate. More interestingly, the ratio is well correlated to solar altitude, which is the angle of the Sun relative to the Earthʼs horizon. It is found that the ratio decreases from 0.8 to 0.2 with the decreasing solar altitude from –17 to –73 degree. Based on this relation, which is described by a linear function, we can construct the Hα sky component and subtract it from the science spectrum. This method has been applied to the LAMOST-MRS-N data, and the contamination level of the Hα sky to nebula is reduced from 40% to less than 10%. The new generated spectra will significantly improve the accuracy of the classifications and the measurements of physical parameters of Galactic nebulae.