bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Flow Alteration Index for Complex River Networks With Cascading Reservoir Systems
Authors: Kumar Hemant , Hwang Jeongwoo , Devineni Naresh , Sankarasubramanian A.
Published: December 2021

Large dams degrade the river’s health by heavily regulating the natural flows. Despite a long history of research on flow regulation due to dams, most studies focused only on the impact of a single dam and ignored the combined impact of flow regulation on a river network. We propose a new Dynamic Flow Alteration Index (DFAI) to quantify the local and cumulative degree of regulation by comparing the observed controlled flows with the naturalized flows based on a moving time horizon for the highly regulated Colorado River Basin. The proposed DFAI matches closely to dam’s localized regulation for headwater gages and starts to diverge as we move downstream due to increase in cumulative impact of the dams. DFAI considers the impact of dam operations on flow characteristics such as shifting of peak flow occurrence and dampening of peak flows. DFAI estimates the degree of regulation to be small for upstream dams and finds the maximum network regulation to be 2.52 years at Glen Canyon reservoir. DFAI also successfully captures the reduction in cumulative regulation when dam operations (e.g., Hoover Dam) bring the altered flow in synchronization with natural regime due to downstream flow requirements. The impact of San Juan River Basin Recovery Implementation Program is also captured by DFAI as the reduction in network regulation drops by 1.5 years for Navajo Dam. Our findings using DFAI suggest the need to develop naturalized flows for major river basins to quantify the flow alteration under continually changing climate and human influences.
Model‐Reduced Adjoint‐Based Inversion Using Deep‐Learning: Example of Geological Carbon Sequestration Modeling
Authors: Xiao Cong , Zhang Shicheng , Ma Xinfang , Jin Jianbing , Zhou Tong
Published: December 2021

As an extension of our previous research on deep‐learning‐based adjoint‐state approach (Xiao, Deng, & Wang, 2021, https://doi.org/10.1029/2020wr027400), we present a two‐level hybrid neural network architecture to efficiently derive a model‐reduced adjoint‐based optimization workflow with a large‐scale inverse modeling example in geological carbon‐storage applications. The first level employs a nonlinear dimensionality reduction technique, that is, deep convolutional autoencoder, owing to its high scalability and the availability of high‐performance deep‐learning libraries for flexible implementation. Analogous to the reduced‐order linear model, the second level emulates a neural‐network‐powered linear transition unit based on the reduced subspace. This hybrid framework provides a readily available model‐reduced adjoint derivation with negligible computational cost and computer storage. Once the gradient is obtained in reduced space, it is correspondingly projected back to full space for the inverse modeling. The performance of the method is verified by estimating the space‐dependent stochastic permeability field using two geological carbon storage (GCS) process‐based multiphase flow models with an increasing complexity. The experimental results indicate that the surrogate model can accurately characterize the spatial‐temporal evolution of the CO2 saturation fields using a relatively small number of training data. Although the proposed inversion workflow achieves comparable results similar to the conventional finite‐difference method, it is faster than high‐fidelity model simulations in several orders of magnitude; hence, it will be a beneficial simulation and modeling tool for engineers to manage the uncertainty of GCS processing.
Hydrogeochemical Response of a Variably Saturated Sulfide‐Bearing Mine Waste‐Rock Pile to Precipitation: A Field‐Scale Study in the Discontinuous Permafrost Region of Northern Canada
Authors: Bao Zhongwen , Bain Jeff , Holland Steven P. , Wilson David , Ptacek Carol J. , Blowes David W.
Published: December 2021

Globally, drainage from sulfide‐bearing waste‐rock piles, containing high concentrations of toxic metal(loid)s, can severely degrade surrounding ecosystems. Waste‐rock piles are typically deposited as unsaturated porous media. The complex physical and chemical heterogeneity of waste rock poses significant challenges to the evaluation of internal hydrological, (bio)geochemical, and mineralogical controls on the magnitude and duration of environmental impacts. An operational‐scale waste‐rock pile located in the discontinuous permafrost region of Northern Canada was well‐instrumented and monitored to examine hydrological processes (including precipitation, evaporation, and infiltration), hydrological and thermal responses to freeze‐thaw and dry‐wet cycles, and concentration‐discharge (cQ) relationships in drainage‐water quantity and quality. The net infiltration (subtraction of evaporation from precipitation) into the waste‐rock pile occurred from May to November, resulting in rainfall‐dominated recharge to pore water, surface seepage, and groundwater. Pronounced variations in water content and temperature in response to freeze‐thaw and dry‐wet cycles and variations in surface topography were observed in regions of the waste‐rock pile impacted by preferential flow pathways. In contrast, distinct variations in water content and temperature were not observed in regions of matrix‐dominated flow pathways. The cQ relationships show chemodynamically controlled dilution behavior for most dissolved constituents (e.g., SO4, Fe, Pb, Zn, Cu, Ca, Mn) in the drainage. Therefore, hydrological processes and (bio)geochemical and mineralogical reactions both play prominent roles in determining drainage‐water chemistry. This work presents an integrated approach to site‐specific monitoring and characterization to evaluate remediation and reclamation options for operational‐scale waste‐rock piles for long‐term ecosystem preservation.
Variability of human fasted venous plasma metabolomic profiles with tourniquet induced hemostasis
Authors: Devi Sarita , Pasanna Roshni M. , Nadiger Nikhil , Ghosh Santu , Kurpad Anura V. , Mukhopadhyay Arpita
Published: December 2021

Venous plasma metabolomics is a potent and highly sensitive tool for identifying and measuring metabolites of interest in human health and disease. Accurate and reproducible insights from such metabolomic studies require extreme care in removing preanalytical confounders; one of these is the duration of tourniquet application when drawing the venous blood sample. Using an untargeted plasma metabolomics approach, we evaluated the effect of varying durations of tourniquet application on the variability in plasma metabolite concentrations in five healthy female subjects. Tourniquet application introduced appreciable variation in the metabolite abundances: 73% of the identified metabolites had higher temporal variation compared to interindividual variation [Intra-Class Correlation (ICC) > 0.50]. As such, we recommend tourniquet application for minimal duration and to wait for 5 min with the needle in situ after removing the tourniquet, to reduce hemostasis-induced variability and false flags in interpretation.
SATB1, genomic instability and Gleason grading constitute a novel risk score for prostate cancer
Authors: Dumke Christoph , Gemoll Timo , Oberländer Martina , Freitag-Wolf Sandra , Thorns Christoph , Glaessgen Axel , Klooster Rinse , van der Maarel Silvère M. , Widengren Jerker , Doehn Christian , Auer Gert , Habermann Jens K.
Published: December 2021

Current prostate cancer risk classifications rely on clinicopathological parameters resulting in uncertainties for prognostication. To improve individual risk stratification, we examined the predictive value of selected proteins with respect to tumor heterogeneity and genomic instability. We assessed the degree of genomic instability in 50 radical prostatectomy specimens by DNA-Image-Cytometry and evaluated protein expression in related 199 tissue-microarray (TMA) cores. Immunohistochemical data of SATB1, SPIN1, TPM4, VIME and TBB5 were correlated with the degree of genomic instability, established clinical risk factors and overall survival. Genomic instability was associated with a GS ≥ 7 (p = 0.001) and worse overall survival (p = 0.008). A positive SATB1 expression was associated with a GS ≤ 6 (p = 0.040), genomic stability (p = 0.027), and was a predictor for increased overall survival (p = 0.023). High expression of SPIN1 was also associated with longer overall survival (p = 0.048) and lower preoperative PSA-values (p = 0.047). The combination of SATB1 expression, genomic instability, and GS lead to a novel Prostate Cancer Prediction Score (PCP-Score) which outperforms the current D’Amico et al. stratification for predicting overall survival. Low SATB1 expression, genomic instability and GS ≥ 7 were identified as markers for poor prognosis. Their combination overcomes current clinical risk stratification regimes.
Kinetic control of nascent protein biogenesis by peptide deformylase
Authors: Bögeholz Lena A. K. , Mercier Evan , Wintermeyer Wolfgang , Rodnina Marina V.
Published: December 2021

Synthesis of bacterial proteins on the ribosome starts with a formylated methionine. Removal of the N-terminal formyl group is essential and is carried out by peptide deformylase (PDF). Deformylation occurs co-translationally, shortly after the nascent-chain emerges from the ribosomal exit tunnel, and is necessary to allow for further N-terminal processing. Here we describe the kinetic mechanism of deformylation by PDF of ribosome-bound nascent-chains and show that PDF binding to and dissociation from ribosomes is rapid, allowing for efficient scanning of formylated substrates in the cell. The rate-limiting step in the PDF mechanism is a conformational rearrangement of the nascent-chain that takes place after cleavage of the formyl group. Under conditions of ongoing translation, the nascent-chain is deformylated rapidly as soon as it becomes accessible to PDF. Following deformylation, the enzyme is slow in releasing the deformylated nascent-chain, thereby delaying further processing and potentially acting as an early chaperone that protects short nascent chains before they reach a length sufficient to recruit other protein biogenesis factors.
A nano phototheranostic approach of toluidine blue conjugated gold silver core shells mediated photodynamic therapy to treat diabetic foot ulcer
Authors: Akhtar Farheen , Khan Asad U. , Qazi Bushra , Kulanthaivel Senthilguru , Mishra Prashant , Akhtar Kafil , Ali Asif
Published: December 2021

Diabetic foot infection caused by multidrug-resistant bacteria, is becoming serious problem. Moreover, polymicrobial biofilms contribute significantly to the persistent infections. In the present study, we investigated the effectiveness of novel toluidine blue conjugated chitosan coated gold–silver core–shell nanoparticles (TBO–chit–Au–AgNPs) mediated photodynamic therapy and demonstrate their use as a nontoxic antibacterial therapy to combat diabetic foot ulcer (DFU) caused by multi-drug resistant strains both in monomicrobial and polymicrobial state of infection. In vitro efficacy of TBO–chit–Au–AgNPs mediated photodynamic therapy (PDT) against polymicrobial biofilms was determined using standard plate count method and compared with that of monomicrobial biofilms of each species. Different anti-biofilm assays and microscopic studies were performed to check the efficacy of TBO–chit–Au–AgNPs mediated PDT, displayed significant decrease in the formation of biofilm. Finally, its therapeutic potential was validated in vivo type-2DFU. Cytokines level was found reduced, using nano-phototheranostic approach, indicating infection control. Expression profile of growth factors confirmed both the pathogenesis and healing of DFU. Hence, we conclude that TBO–chit–Au–AgNPs mediated PDT is a promising anti-bacterial therapeutic approach which leads to a synergistic healing of DFU caused by MDR bacterial strains.
Living in a pandemic: changes in mobility routines, social activity and adherence to COVID-19 protective measures
Authors: Lucchini Lorenzo , Centellegher Simone , Pappalardo Luca , Gallotti Riccardo , Privitera Filippo , Lepri Bruno , De Nadai Marco
Published: December 2021

Non-Pharmaceutical Interventions (NPIs), aimed at reducing the diffusion of the COVID-19 pandemic, have dramatically influenced our everyday behaviour. In this work, we study how individuals adapted their daily movements and person-to-person contact patterns over time in response to the NPIs. We leverage longitudinal GPS mobility data of hundreds of thousands of anonymous individuals to empirically show and quantify the dramatic disruption in people’s mobility habits and social behaviour. We find that local interventions did not just impact the number of visits to different venues but also how people experience them. Individuals spend less time in venues, preferring simpler and more predictable routines, also reducing person-to-person contacts. Moreover, we find that the individual patterns of visits are influenced by the strength of the NPIs policies, the local severity of the pandemic and a risk adaptation factor, which increases the people’s mobility regardless of the stringency of interventions. Finally, despite the gradual recovery in visit patterns, we find that individuals continue to keep person-to-person contacts low. This apparent conflict hints that the evolution of policy adherence should be carefully addressed by policymakers, epidemiologists and mobility experts.
Label-free and sensitive detection of RNA demethylase FTO with primer generation rolling circle amplification
Authors: Han Xiaoxia , Li Yueying , Wang Zi-Yue , Liu Ling-Zhi , Qiu Jian-Ge , Liu Bing-Jie , Zhang Chun-yang
Published: December 2021

We develop a label-free fluorescent method for sensitive detection of FTO activity using MazF-mediated primer generation rolling circle amplification.
Effects of vacancy defects on the interfacial thermal resistance of partially overlapped bilayer graphene
Authors: Wang Bing-cheng , Cao Qun , Shao Wei , Cui Zheng
Published: December 2021

The effects of the overlapping area of partially overlapped bilayer graphene and the interlayer sp3 bonding of adjacent vacancies on the interfacial thermal resistance are studied by molecular dynamics simulations.
A simulation study on the subdiffusion of polymer chains in crowded environments containing nanoparticles
Authors: Lu Rong-Xing , Huang Jian-Hua , Luo Meng-Bo
Published: December 2021

The subdiffusion-to-normal diffusion transition of polymer chains originates from the change of the adsorption mode of polymer chains on attractive nanoparticles.
Tailoring graphene-supported Ru nanoparticles by functionalization with pyrene-tagged N-heterocyclic carbenes
Authors: García-Zaragoza Adrián , Cerezo-Navarrete Christian , Mollar-Cuni Andrés , Oña-Burgos Pascual , Mata Jose A. , Corma Avelino , Martínez-Prieto Luis M.
Published: December 2021

Controlling the reactivity and stability of graphene-supported Ru NPs by modifying their surface with pyrene-tagged N-heterocyclic carbene ligands.
Towards understanding photon absorption and emission in MgAl layered double hydroxide
Authors: Gevers Bianca R. , Roduner Emil , Labuschagné Frederick J. W. J.
Published: December 2021

MgAl-LDH, a UV-Vis luminescent material, reveals suitability to study in-depth the charge separation and temperature-dependent recombination pathways in LDHs.
Discovery of new chiral sulfonamides bearing benzoxadiazole as HIF inhibitors for non-small cell lung cancer therapy: design, microwave-assisted synthesis, binding affinity,in vitroantitumoral activities andin silicostudies
Authors: Kahraman Demet Taşdemir , Karaküçük-İyidoğan Ayşegül , Saygideger Yasemin , Oruç-Emre Emine Elçin , Taskin-Tok Tugba , Başaran Eyüp , İlhan Sedat , Demir Burcu Saygıdeğer , Üren Aykut , Bayram Hasan
Published: December 2021

Thirty-four chiral compounds having benzoxadiazole and sulfonamide moieties on the skeleton have been synthesized. The in vitro cytotoxic activity and apoptotic effects of these compounds have been evaluated using the A549 lung cancer cell line.
Ni(OH)2 Coated CoMn-layered double hydroxide nanowires as efficient water oxidation electrocatalysts
Authors: Li Xue , Patil Komal , Agarwal Ashutosh , Babar Pravin , Jang Jun Sung , Chen Xing , Yoo Yung Tae , Kim Jin Hyeok
Published: December 2021

Hierarchical heterostructures with a core of CoMn-LDH nanowires and a shell of Ni(OH)2 were successfully synthesized by a facile hydrothermal method followed by electrodeposition.
Magnetic nanoribbons with embedded cobalt grown inside single-walled carbon nanotubes
Authors: Krichevsky Denis M. , Shi Lei , Baturin Vladimir S. , Rybkovsky Dmitry V. , Wu Yangliu , Fedotov Pavel V. , Obraztsova Elena D. , Kapralov Pavel O. , Shilina Polina V. , Fung Kayleigh , Stoppiello Craig T. , Belotelov Vladimir I. , Khlobystov Andrei , Chernov Alexander I.
Published: December 2021

Magnetic nanoribbons were grown inside single-walled carbon nanotubes. The fingerprint features of CoPc nanoribbons we identified and confirmed the encapsulation. An impact of magnetic Co atoms was verified using TMOKE measurements.
The 3D-structure-mediated growth of zero-dimensional Cs4SnX6 nanocrystals
Authors: Xu Kaimin , Wei Qi , Wang Hao , Yao Bing , Zhou Wenjia , Gao Rong , Chen Hao , Li Hansheng , Wang Jingtian , Ning Zhijun
Published: December 2021

A 3D structure-mediated growth method is developed to synthesize high quality zero dimensional Cs4SnX6 nanocrystals.
Anomalous polarization pattern evolution of Raman modes in few-layer ReS2 by angle-resolved polarized Raman spectroscopy
Authors: Wu Ruowei , Qi Mei , Zhao Qiyi , Huang Yuanyuan , Zhou Yixuan , Xu Xinlong
Published: December 2021

The polarization pattern evolution of both in-plane and out-of-plane Raman modes is systematically investigated by angle-resolved polarized Raman spectroscopy for few-layer ReS2.
Asymmetric synthesis of isochromanone derivatives via trapping carboxylic oxonium ylides and aldol cascade
Authors: Lang Jiawen , Wang Siyuan , He Changli , Liu Xiaohua , Feng Xiaoming
Published: December 2021

A highly enantioselective cascade Z-selective-1,3-OH insertion/aldol cyclization of ketoacids with diazoketones involving carboxylic oxonium ylides was achieved by using a bimetallic Rh(ii)/chiral N,N′-dioxide-Fe(iii) or Sc(iii) complex catalyst.
From Speech Acoustics to Communicative Participation in Dysarthria: Toward a Causal Framework
Authors: Borrie Stephanie A. , Wynn Camille J. , Berisha Visar , Barrett Tyson S.
Published: December 2021

Purpose:

We proposed and tested a causal instantiation of the World Health Organization's International Classification of Functioning, Disability and Health (ICF) framework, linking acoustics, intelligibility, and communicative participation in the context of dysarthria.

Method:

Speech samples and communicative participation scores were collected from individuals with dysarthria (
n
= 32). Speech was analyzed for two acoustic metrics (i.e., articulatory precision and speech rate), and an objective measure of intelligibility was generated from listener transcripts. Mediation analysis was used to evaluate pathways of effect between acoustics, intelligibility, and communicative participation.

Results:

We observed a strong relationship between articulatory precision and intelligibility and a moderate relationship between intelligibility and communicative participation. Collectively, data supported a significant relationship between articulatory precision and communicative participation, which was almost entirely mediated through intelligibility. These relationships were not significant when speech rate was specified as the acoustic variable of interest.

Conclusion:

The statistical corroboration of our causal instantiation of the ICF framework with articulatory acoustics affords important support toward the development of a comprehensive causal framework to understand and, ultimately, address restricted communicative participation in dysarthria.
Implementation of a DSP‐based speed‐sensorless adaptive control for permanent‐magnet synchronous motor drives with uncertain parameters using linear matrix inequality approach
Authors: Tsai Ming‐Fa , Tseng Chung‐Shi , Li Nan‐Sin , Jan Rong‐Maw
Published: December 2021

This paper presents a novel speed sensorless adaptive control scheme for the uncertain permanent‐magnet synchronous motor (PMSM) drive system using a linear matrix equalities approach with a digital signal processing (DSP) chip. The dynamic model of the PMSM drive with eight error states based on the structure of speed estimator, speed and current controllers is developed. The speed controller, current controller and rotor speed and position estimators are considered simultaneously and designed together. In addition, a three‐parameter observer is also designed and the adaptive control law is derived in the light of Lyapunov stability theorem. The objective of this study is to determine the two estimation gains and the six control gains such that the closed‐loop system is stable. The stability condition of the system can be characterized in terms of some linear matrix inequalities (LMIs). The LMIs problem can be efficiently solved with the help of MATLAB simulation tool. Differently from the conventional proportional‐integral controller, a novel controller with a low‐pass filter instead of a pure integrator is proposed. By a suitable adjustment for a design parameter, the steady‐state error can also be improved. Numerical solutions of the controller and the estimator gains and simulation examples are provided to illustrate the design procedure and corresponding performances. The experimental results by using a TI TMS320F28335 DSP chip with the speed reference 400, 700, 1000 RPM, respectively and sudden change of the reference demonstrate the performance of the proposed control scheme.
Study of improved signal‐based merge strategy in work zone areas based on Cellular Automata simulation
Authors: Duan Ke , Yan Xuedong , Hang Junyu , Li Xiaomeng
Published: December 2021

Work zones have critical effects on traffic safety and efficiency. Previous researchers have developed lots of merge strategies to regulate drivers’ behaviours, which can be divided into early merge and late merge. As a special kind of late merge, signal‐based merge strategy was proposed in recent years to reduce traffic conflicts and increase throughput at bottlenecks. Although traffic signal has been confirmed to improve the traffic in work zone areas effectively, the existing strategy still has limitations that require further improvements. In this research, an improved signal‐based merge (IM) strategy was proposed to fulfil the research gaps. The strategy included a calculation method of green time considering the relationship between arrival traffic and the bottleneck's capacity and a dynamic signal‐phase conversion method. Based on the Cellular Automata simulation, the effectiveness of the IM strategy was verified through parameter sensitive analysis and comparative study with the existing merge strategies. The results showed that the IM strategy could lead to greater throughputs, lower traffic delays, less aggressive merge and more balanced queue length. Furthermore, the IM strategy also showed great stability in response to the changes of parameters and the imbalance of arrival traffic. Overall, the proposed IM strategy is considered more effective in improving the traffic management in work zone areas and is feasible to be applied in practice.
Moving target detection and tracking with multiplatform radar network (MRN)
Authors: Geng Zhe , Wang Beining , Yan He , Zhang Jindong , Zhu Daiyin
Published: December 2021

A multiplatform radar network (MRN) composed of multiple transmitting and receiving facilities is advantageous over monostatic radar in moving target detection (MTD) and tracking due to the diversity gain. Within the framework of the Internet of Battlefield Things (IoBT), the authors propose that the airborne platforms equipped with the cognitive multimodal radar (CMR), the subarray‐based MIMO radar (SMR), the active electronically scanned array (AESA) radar, and the adaptive radar countermeasures (ARC) should team up in target detection and tracking. To obtain better target detection and tracking performance, the probing signals from the CMR, the SMR, and the AESA radar are adaptively optimised based on the scenario under consideration. The ARC consists of two parts: 1) RF signal sensing and recognition with deep neural network (DNN), that is, to detect, identify, and localise multiple radio frequency emitters; 2) intelligent fake return creation and jamming to confuse the enemy radars in real time in the field. This work aims to serve as a good reference for future researchers interested in developing MRN with diverse nodes and the general teaming of radars on the battlefield.
Color Doppler Ultrasound versus Computed Tomography Angiography for Preoperative Anterolateral Thigh Flap Perforator Imaging: A Systematic Review and Meta-Analysis
Authors: Moore Reece , Mullner Donna , Nichols Georgina , Scomacao Isis , Herrera Fernando
Published: December 2021

Background The anterolateral thigh (ALT) perforator flap is a commonly used flap with a predictable, though often variable, perforator anatomy. Preoperative imaging with color Doppler ultrasound (CDU) and computed tomography angiography (CTA) of ALT flap perforators can be a useful tool for flap planning. This study provides a complete review and analysis of the relevant preoperative ALT imaging literature.

Methods Studies related to preoperative CDU and CTA imaging were reviewed, and information related to imaging method, sensitivity, false-positive rates, and perforator course identification (musculocutaneous vs. septocutaneous) were analyzed.

Results A total of 23 studies related to preoperative ALT flap CDU and CTA imaging were included for review and analysis. Intraoperative perforator identification was compared with those found preoperatively using CDU (n = 672) and CTA (n = 531). Perforator identification sensitivity for CDU was 95.3% (95% CI: 90.9–97.6%) compared with the CTA sensitivity of 90.4% (95% confidence interval [CI]: 74.4–96.9%). The false-positive rate for CDU was 2.8% (95% CI: 1.1–4.5%) compared with 2.4% (95% CI: 0.7–4.1%) for CTA. Accuracy of perforator course identification was 95.5% (95% CI: 93.6–99.2%) for CDU and 96.9% (95% CI: 92.7–100.1%) for CTA.

Conclusion CDU provides the reconstructive surgeon with greater preoperative perforator imaging sensitivity compared with CTA; however, false-positive rates are marginally higher with preoperative CDU. Preoperative imaging for ALT flap design is an effective tool, and the reconstructive surgeon should consider the data presented here when selecting a flap imaging modality.
A Review, Tabulation, and Parameterization of M-Series X-Ray Production Cross Sections for Proton and Helium Ion Impact
Authors: Singh Balwinder , Shehla  , Puri Sanjiv
Published: December 2021

In the present work, the experimental total and line resolved M-series x-ray production cross sections (XRPCSs) for different elements with Z = 59–92 for 0.05–39.34 MeV proton and 0.2–6.0 MeV He ion (3He/4He) impact reported by different research groups until December 2020 have been compiled in tabular form. A status of different physical parameters, namely, the ionization cross sections, x-ray emission rates, fluorescence yields, and Coster–Kronig and super Coster–Kronig yields, required to calculate the theoretical M-series XRPCSs have been reviewed. The tabulated experimental total M-series XRPCSs for different elements are found to exhibit universal scaling similar to that shown by the theoretical cross sections. These tabulated experimental cross sections for different elements have been parameterized in order to provide empirical cross sections for use in different applications.
New opportunities for nuclear and atomic physics on the femto- to nanometer scale with ultra-high-intensity lasers
Authors: Fu Changbo , Zhang Guoqiang , Ma Yugang
Published: December 2021

There are a number of puzzles concerning physics on the scale of nanometers to femtometers, including the neutron lifetime, the proton charge radius, and the possible existence of the deep Dirac level. With the development of high-intensity laser technology, lasers today can induce extremely strong electromagnetic fields. Electrons in the deep shells of atoms as well as the atomic nucleus itself can be affected by these fields. This may provide a new experimental platform for studies of physical processes on the femto- to nanometer scale, where atomic physics and nuclear physics coexist. In this paper, we review possible new opportunities for studying puzzles on the femto- to nanometer scale using high-intensity lasers.
Emission of fused silica and KBr samples in the UV and visible spectral ranges under irradiation with 2.7 MeV electrons
Authors: Baksht E. Kh. , Alekseev B. A. , Burachenko A. G. , Vukolov A. V. , Potylitsyn A. P. , Tarasenko V. F. , Uglov S. R. , Shevelev M. V.
Published: December 2021

Fused silica and KBr samples were irradiated with a 2.7 MeV electron beam. The emission of fused silica and KBr samples in the UV and visible regions was studied under various experimental conditions. Numerical simulation of optical emission was carried out using the GEANT4 computer platform. Simulations of energy spectra and angular distributions of the beam electrons were performed for different target thicknesses. The results reveal the effect of scattering of the beam electrons on the angular distribution of Cherenkov radiation in fused silica samples with thicknesses exceeding the electron path length.
Photochromism of UV-annealed Fe-doped SrTiO3
Authors: Wu Yifeng , Bowes Preston C. , Baker Jonathon N. , Irving Douglas L.
Published: December 2021

High-temperature annealing coupled with above bandgap UV illumination is an emerging approach to manipulate defect chemistries and resultant properties of electroceramics. To explore defect-processing-property relationships in these materials, an advanced multiphysics and multiscale model has been developed, which involves (a) high-fidelity first principles simulations of defect energies, (b) grand canonical thermodynamics of defect equilibria, (c) UV-perturbed defect formation energies from Shockley–Read–Hall generation and recombination, and (d) finite-element analyses of electrostatic potential and defect redistribution. Using this model, bottom-up insights into defect mechanisms associated with the UV-induced brown photochromism of Fe-doped SrTiO3 at high temperatures are provided. It is found that UV illumination leads to dissociation of the FeTi-vO complex and reduction in the oxygen vacancy concentration through exchange with the gas reservoir. Changes to these defect populations cause reionization of the FeTi defect from −1 to 0 charge state to maintain charge neutrality. This collectively gives rise to an increased concentration of FeTi0, which is the source of brown chromism. In addition, this model reproduces the experimentally observed electrical resistance degradation of samples annealed in this manner due to the increasing hole concentration in the material with time. The present model itself offers a route to guide and facilitate future efforts in this field.
An in situ ambient and cryogenic transmission electron microscopy study of the effects of temperature on dislocation behavior in CrCoNi-based high-entropy alloys with low stacking-fault energy
Authors: Fang Yan , Chen Yujie , Chen Bing , Li Suzhi , Gludovatz Bernd , Park Eun Soo , Sheng Guan , Ritchie Robert O. , Yu Qian
Published: December 2021

Temperature is known to affect deformation mechanisms in metallic alloys. As temperature decreases, the stacking-fault energy in many face-centered cubic (fcc) alloys decreases, resulting in a change of deformation mode from dislocation slip to deformation twinning. Such an impact of temperature can be more complex in compositionally heterogeneous microstructures that exhibit, for example, local concentration fluctuation such as that in multi-principal element alloys. In this work, we compare the dislocation behavior and mechanical properties of a fcc Cr20Mn10Fe30Co30Ni10 high-entropy alloy at ambient and liquid-nitrogen temperatures. We find that a network of stacking faults is formed by uniformly extended dislocations at ambient temperatures with low stacking-fault energy, whereas at lower temperatures, uneven dissociation of dislocations becomes significant, which results in severe dislocation pile-ups together with their pronounced entanglement. Our findings indicate that as the stacking-fault energy decreases with decreasing temperature, the heterogeneity of the distribution of elements becomes more dominant in tuning the local variation of lattice resistance. As a result, the change in dislocation behavior at low temperatures strongly affects microstructural evolution and consequently leads to significantly more pronounced work hardening.
Nano-analytical investigation of the forming process in an HfO2-based resistive switching memory
Authors: Lefevre Gauthier , Dewolf Tristan , Guillaume Nicolas , Blonkowski Serge , Charpin-Nicolle Christelle , Jalaguier Eric , Nowak Etienne , Bernier Nicolas , Blomberg Tom , Tuominen Marko , Sprey Hessel , Audoit Guillaume , Schamm-Chardon Sylvie
Published: December 2021

Metal oxide-based resistive random access memory devices are highly attractive candidates for next-generation nonvolatile memories, but the resistive switching phenomena remain poorly understood. This article focuses on the microscopic understanding of the initial forming step, which is decisive for the switching process. The integrated resistive switching memory effect in Ti/HfO2/TiWN metal insulator metal structures is studied. After forming, transmission electron microscopy investigations pointed out the presence of a funnel-shaped region, in the ON state of the cell, where slightly oxidized Ti (TiOx) was present within HfO2 dielectric. Modeling of the measured ON state conductance of the cell with the semi-classical approximation is consistent with a conductive nanometric TiOx filament (or a sum of sub-nanometric TiOx filaments) present in the funnel-shaped region. The conductive area is likely formed by diffusion after the dielectric breakdown.
Digital electronics using dielectric elastomer structures as transistors
Authors: Ciarella L. , Richter A. , Henke E.-F. M.
Published: December 2021

Dielectric elastomers (DEs) are soft and stretchable structures that are typically used as actuators, sensors, and energy harvesters and can perform basic signal processing tasks. Thus, they can be used to create multi-functional and autonomous DE structures, with intrinsic information processing capabilities, that require fewer external components. This contribution introduces how to assemble electronic circuits with DEs, in a similar way to how transistors are employed in conventional electronics. The focus is on the design of digital circuits. At first, parallels between digital signal processing with DEs and with conventional transistors are shown. After describing the differences in the working conditions (e.g., working voltages) of the two structures, it is demonstrated that various design techniques, commonly adopted in conventional electronics, can be used to build DE electronics. The functioning is demonstrated by presenting alternative ways of designing NOR and XOR gates, reducing, in the latter case, the number of components required. Moreover, pass transistor logic is employed to realize a DE multiplexer. This work illustrates a consistent method to realize digital circuits with DEs, and it demonstrates how electronic design techniques can be adapted to work with DEs. It shows that DE circuits can be built starting from their conventional counterpart, obtaining improved devices.
Migration dynamics of excitons/biexcitons induced by a funnel-like nonuniform compression strain over organic polymers
Authors: Shi Xueyi , Zhang Maomao , Wang Wenjing , Gao Kun
Published: December 2021

As a promising strategy, strain engineering has been employed on different semiconductor materials, aiming to modulate their photoelectric properties, thus innovate device applications. An interesting experimental result is the directional exciton migration induced by creating some local nonuniform strains in materials, such as “exciton funneling.” In this Letter, to clarify the dynamical mechanism and the impacting factors, we theoretically investigate the migration dynamics of excitons/biexcitons along organic polymers induced by a funnel-like nonuniform compression strain. First, the migration dynamics of an exciton/biexciton are separately demonstrated right after the strain created. It is found that both of them will migrate toward the strain center with the speeds up to 7–10 nm/ps, comparable with the experimental observations in a bending ZnO microwire, where the difference between the exciton and biexciton migration dynamics is also emphasized. We attribute the present exciton/biexciton migration mechanism to the strain-induced gradient of the exciton/biexciton creation energy along polymers. Furthermore, some typical factors impacting the exciton migration dynamics are considered, such as the strain gradient, the initial ratio of the exciton located in the strain region, the electron-lattice interaction, etc. Finally, based on these findings, we briefly discuss the possible results about the strain-modulated luminescence of organic polymers.
In-plane dynamic crushing of a novel gradient square honeycomb with enhanced energy absorption
Authors: Wang Wei Min , Chen Wang Long , Hu Jun
Published: December 2021

Due to the unstable structural characteristics of square cell elements, square honeycombs undergo slip deformation to the sides when the honeycomb is impacted at middle and low velocities, and consequently, the energy absorption capacities are low. To improve the energy absorption and modify the dynamic crushing behavior of the square honeycomb, a novel square honeycomb was proposed in which rods are added to the interior of the square cell elements. Subsequently, two graded gradient honeycombs and a “buffer” honeycomb were established based on the novel square unit cell, and their energy absorption properties were investigated. Through numerical simulations of the in-plane impact, it was demonstrated that one of the gradient square honeycombs exhibited the best specific energy absorption (34.92% higher than that of the square honeycomb) under low-velocity crushing, and the buffered square honeycomb showed the best crushing force efficiency (218.68% larger than that of the square honeycomb) for a mid-velocity collision. Furthermore, the slip degree of the honeycomb deformation mode was strongly inhibited for one of the novel square honeycombs, which exhibited the zero Poisson ratio effect. In addition, the effects of various factors, such as the geometric configuration and impact velocity, on the energy absorption performance were explored. This study offers novel ideas for improving the abilities of traditional honeycomb structures.
Homemade-HEMT-based transimpedance amplifier for high-resolution shot-noise measurements
Authors: Shimizu Takase , Hashisaka Masayuki , Bohuslavskyi Heorhii , Akiho Takafumi , Kumada Norio , Katsumoto Shingo , Muraki Koji
Published: December 2021

We report a cryogenic transimpedance amplifier (TA) suitable for cross-correlation current-noise measurements. The TA comprises homemade high-electron-mobility transistors with high transconductance and low noise characteristics, fabricated in an AlGaAs/GaAs heterostructure. The low input-referred noise and wide frequency band of the TA lead to a high resolution in current-noise measurements. The TA’s low input impedance suppresses unwanted crosstalk between two distinct currents from a sample, justifying the advantage of the TA for cross-correlation measurements. We demonstrate the high resolution of a TA-based experimental setup by measuring the shot noise generated at a quantum point contact in a quantum Hall system.
Low-energy O+ ion beam induced chemical vapor deposition using hexamethyldisilane or hexamethyldisilazane for silicon dioxide film formation
Authors: Yoshimura Satoru , Sugimoto Satoshi , Takeuchi Takae , Kiuchi Masato
Published: December 2021

A methodology for silicon dioxide (SiO2) film formation by an ion beam induced chemical vapor deposition (IBICVD) method using hexamethyldisilane (HMDS) or hexamethyldisilazane (HMDSN) is presented in this paper. In this method, an O+ ion beam was injected onto a substrate in conjunction with the source material (HMDS or HMDSN). The substrate temperature was set at room temperature. The O+ ion energy was 100 eV. After the experiment, a film was found to be deposited on the substrate and the film thickness was about 50 nm in both HMDS and HMDSN cases. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy of the deposited films showed that SiO2 films were formed on the substrates. XPS data of the film which was prepared by the injection of both O+ ions and HMDS to the substrate showed that no obvious peak was observed in the C1s region. On the contrary, a small amount of carbon was included in the film when the film was prepared by the injection of O+ ions in conjunction with HMDSN. These results suggest that HMDS is more suitable than HMDSN as the source material for SiO2 film formation when using the IBICVD method.
Optimization of selective-area regrown n-GaN via MOCVD for high-frequency HEMT
Authors: Zhang Lian , Cheng Zhe , He Yawei , Xu Jianxing , Jia Lifang , Wang Xinyuan , Zhang Shiyong , Tan Wei , Zhang Yun
Published: December 2021

The selective-area regrowth (SAG) n-type GaN source/drain electrode has been widely used in high electron mobility transistors (HEMTs) for high-frequency applications. Previous studies focused only on device performances, but not on SAG n+-GaN in devices. This paper studies electron concentration and mobility of SAG n+-GaN on InAlN/GaN HEMTs via metal-organic chemical vapor deposition (MOCVD). It is revealed that electron mobility of SAG GaN is significantly affected by thickness. The decrease in mobility in a thin GaN may be attributed to regrowth interface defects. A gas flow model on the regrowth region is proposed to guide the regrowth of SAG GaN for improving the electron mobility. A high electron mobility of 138 cm2/V s with an electron concentration of 5.2 × 1019/cm3 is obtained from an 80-nm n+-GaN with the regrowth width of 10 μm. Due to the high doping level, the nonalloy metal-semiconductor contact resistance (Rm-GaN) is as low as 0.041 Ω mm. The interface resistance (Rint) between GaN and 2DEG is extracted using transfer length measurement (TLM) models and found to be 0.106 Ω mm. The on-resistance (Ron) is 0.753 Ω mm for InAlN/GaN HEMT with a source-drain metal spacing (Lsd metal) of 2 μm.
Elements of Stochastic Methods
Authors: Gardiner Crispin
Published: December 2021

This book provides a compact practical exposition of the stochastic methods and their applications for a wide range of fields, including population dynamics, infectious diseases, financial modeling, hydrology, physics, quantum optics, chemistry, and many others. The aim is to give practitioners an idea of how to formulate their current problem stochastically, and how to get an idea of what the predictions of such modeling are.

Elements of Stochastic Methods features:A treatment based on Markov processes, including an outline of their theoretical foundations, and a description of basic algorithms for simulating Markov processesA straightforward and practical formulation of stochastic differential equations and Ito calculus, including simulation methodsHeavy-tailed processes, Mandelbrot's fractional Brownian motion, as well as the more traditional diffusion and jump processes

This book is an essential resource for researchers, professionals, and graduate students in physics and in any field where random processes are relevant.
Introduction
Authors: Gardiner Crispin
Published: December 2021

The everyday world around us is a mixture of predictability and chance. The “exact sciences,” such as physics or chemistry, are built on the idea that there are definite laws governing observable phenomena, and these sciences have had extraordinary success in elucidating the relevant laws, and in using these laws to describe the world.
The Wiener Process and Brownian Motion
Authors: Gardiner Crispin
Published: December 2021

Brownian motion has two rather different connotations. On the one hand, there is the point of view of the scientist, which sees Brownian motion as the phenomenon observed when a small particle suspended in a fluid is seen to undergo irregular and incessant motion. This what we will call physical Brownian motion.
Escape and Extinction
Authors: Gardiner Crispin
Published: December 2021

The general problem of how long a random variable remains within a definite region has many applications to natural phenomena. The following are some typical examples.
Lévy Processes
Authors: Gardiner Crispin
Published: December 2021

Markov processes that are homogeneous in time and space are known as Lévy processes. The Wiener process has this property, but there is a more extensive class of such processes, which can all be described by a master equation or by a limit of a master equation.
Non-commutative methods in additive combinatorics and number theory
Authors: Shkredov I. D.
Published: December 2021

The survey is devoted to applications of growth in non- Abelian groups to a number of problems in number theory and additive combinatorics. We discuss Zaremba’s conjecture, sum-product theory, incidence geometry, the affine sieve, and some other questions.

Bibliography: 149 titles.
Wrist‐worn devices for the measurement of heart rate and energy expenditure: A validation study for the Apple Watch 6, Polar Vantage V and Fitbit Sense
Authors: Hajj‐Boutros Guy , Landry‐Duval Marie‐Anne , Comtois Alain Steve , Gouspillou Gilles , Karelis Antony D.
Published: December 2021

The purpose of this study was to investigate the accuracy of 3 recently released wrist‐worn devices (Apple Watch 6, Polar Vantage V and Fitbit Sense) for heart rate and energy expenditure during various activities. The study population consisted of 60 young healthy individuals (30 men and 30 women; age: 24.9 ± 3.0 years, BMI: 23.1 ± 2.7 kg/m2). Heart rate and energy expenditure were measured using the Polar H10 and Metamax 3B, respectively (reference measures) as well as with the 3 wrist‐worn devices during 5 different activities (sitting, walking, running, resistance exercises and cycling). The Apple Watch 6 displayed the highest level of accuracy for heart rate measurement with a coefficient of variation (CV) (%) of less than 5% for all 5 activities, whereas the Polar Vantage V and the Fitbit Sense presented various degrees of accuracy (from high to poor accuracy) dependent on the activity (CVs between 2.44‐8.80% and 4.14‐10.76%, respectively). As for energy expenditure, all 3 devices displayed poor accuracy for all 5 physical activities (CVs between 14.68‐24.85% for Apple Watch 6, 16.54‐25.78% for Polar Vantage V and 13.44‐29.66% for Fitbit Sense). Results of the present study indicate that the Apple Watch 6 was the most accurate for measuring heart rate across all 5 activities, whereas variable levels of accuracy for heart rate measurement for the Polar Vantage V and the Fitbit Sense were observed depending on the activity. As for energy expenditure, all 3 devices showed poor accuracy during all activities.

Highlights

The Apple Watch 6 was the most accurate for measuring heart rate, whereas the Polar Vantage V and Fitbit Sense showed variable results dependent on the activity

The Apple Watch 6, Polar Vantage V and Fitbit Sense showed poor accuracy for energy expenditure during 5 different physical activities

Healthcare care professionals, athletes/coaches and the general population may want to proceed with caution on the clinical utility of energy expenditure of these devices during the implementation of an exercise training or nutritional programme.