bluuebunny/crossref_metadata_2025 huggingface dataset:
Node and edge nonlinear eigenvector centrality for hypergraphs
Authors: Tudisco Francesco , Higham Desmond J.
Published: September 2021

Network scientists have shown that there is great value in studying pairwise interactions between components in a system. From a linear algebra point of view, this involves defining and evaluating functions of the associated adjacency matrix. Recent work indicates that there are further benefits from accounting directly for higher order interactions, notably through a hypergraph representation where an edge may involve multiple nodes. Building on these ideas, we motivate, define and analyze a class of spectral centrality measures for identifying important nodes and hyperedges in hypergraphs, generalizing existing network science concepts. By exploiting the latest developments in nonlinear Perron−Frobenius theory, we show how the resulting constrained nonlinear eigenvalue problems have unique solutions that can be computed efficiently via a nonlinear power method iteration. We illustrate the measures on realistic data sets.
Development of a bimetal–organic framework–polypyrrole composite as a novel fiber coating for direct immersion solid phase microextractionin situsupercritical fluid extraction coupled with gas chromatography for simultaneous determination of furfurals in dates
Authors: Raofie Farhad , Falsafi Zohreh
Published: September 2021

A new, simple, hyphenated technique couples supercritical fluid extraction and direct immersion SPME with GC-FID (SFE-DI-SPME-GC-FID) for the determination of 2-furaldehyde (2-F) and 5-hydroxymethylfurfural (5-HMF) in solid foods.
Fluxionality by quantum tunnelling: nonclassical 21-homododecahedryl cation rearrangement re-revisited
Authors: Kozuch Sebastian , Karton Amir , Jalife Said , Merino Gabriel
Published: September 2021

The 21-homododecahedryl cation is a unique system in terms of its fluxionality based on two different rearrangements. We report the quantum tunneling effects that drive the reactions at temperatures where the semi-classical kinetics are impossible.
Bio-instructive materials on-demand – combinatorial chemistry of peptoids, foldamers, and beyond
Authors: Herlan Claudine Nicole , Feser Dominik , Schepers Ute , Bräse Stefan
Published: September 2021

Combinatorial chemistry allows for the rapid synthesis of large compound libraries for high throughput screenings in biology, medicinal chemistry, or materials science.
Synthesis and evaluation of peptidic thrombin inhibitors bearing acid-stable sulfotyrosine analogues
Authors: Dowman Luke J. , Agten Stijn M. , Ripoll-Rozada Jorge , Calisto Bárbara M. , Pereira Pedro José Barbosa , Payne Richard J.
Published: September 2021

We describe the incorporation of two acid-stable mimics of sulfotyrosine into thrombin-inhibiting peptides and assess their activity and binding mode.
Intramolecular charge transfer enhancing strategy based MAO-A specific two-photon fluorescent probes for glioma cell/tissue imaging
Authors: Fang Haixiao , Shi Riri , Chen Ding , Qu Yunwei , Wu Qiong , Yang Xuekang , Lu Xiaomei , Zhang Cheng-Wu , Li Lin , Lim Kah-Leong
Published: September 2021

Picking MAO-A: a new ICT-based two-photon small molecule fluorescent probe (A3), successfully detected endogenous MAO-A activity from a variety of biological samples, including live mammalian cells and human glioma tissue.
1,1′-Ferrocenedicarboxylic acid/tetrahydrofuran induced precipitation of calcium carbonate with a multi-level structure in water
Authors: Zhou Lihong , Wang Guanghui , Du Jie , Zhao Qinjiang , Pei Xiang
Published: September 2021

Multi-molecules co-regulate the orderly morphology and structure of CaCO3 precipitates and the influence of ether bonds on the formation of CaCO3 precipitates.
A facile template method to fabricate one-dimensional Fe3O4@SiO2@C/Ni microtubes with efficient catalytic and adsorption performance
Authors: Yang Liting , Zheng Jing , Xu Jingli , Zhang Baishun , Zhang Min
Published: September 2021

The Fe3O4@SiO2@C/Ni microtubes were well constructed with MoO3 microrods as sacrificing template, which manifested excellent performance as both catalyst and adsorbent.
Electrostatic patterning on graphene with dipolar self-assembly
Authors: Abbasian Hamed , Rochefort Alain
Published: September 2021

The presence of a self-assembly dipole shifts the neutrality point and introduces electrostatic patterns on graphene.
Adsorption of a single Pt atom on graphene: spin crossing between physisorbed triplet and chemisorbed singlet states
Authors: Ahn Jeonghwan , Hong Iuegyun , Lee Gwangyoung , Shin Hyeondeok , Benali Anouar , Kwon Yongkyung
Published: September 2021

Diffusion Monte Carlo calculations show that a triplet-to-singlet spin crossing takes place in a Pt atom adsorbed on graphene.
Spherand complexes with Li+ and Na+ ions in the gas phase: encapsulation structure and characteristic unimolecular dissociation
Authors: Kida Motoki , Wada Kanako , Muramatsu Satoru , Shang Rong , Yamamoto Yohsuke , Inokuchi Yoshiya
Published: September 2021

A spherand·Li+ complex shows characteristic unimolecular dissociation ascribed to the efficient release of dimethyl ethers, providing dibenzofuran frames.
Topological principles of protein folding
Authors: Scalvini Barbara , Sheikhhassani Vahid , Mashaghi Alireza
Published: September 2021

Native topology correlates with folding rate: entangled topological relationships between protein loops facilitate folding. High numbers of topologically independent units (circuits) – normalized by size – are associated with fast folding kinetics.
Physical, spectroscopic, and biological properties of ruthenium and osmium photosensitizers bearing diversely substituted 4,4′-di(styryl)-2,2′-bipyridine ligands
Authors: Vinck Robin , Karges Johannes , Tharaud Mickaël , Cariou Kevin , Gasser Gilles
Published: September 2021

Subtle structural modifications of a ruthenium complex significantly affect its performances as a photosensitizer for photodynamic therapy, including its cellular uptake and its phototoxicity.
Electrospray interfacial polymerization for a loose NF membrane: super-selective dye separation in saline dye wastewater treatment
Authors: Kang Yesol , Jang Jaewon , Lee Yunho , Kim In S.
Published: September 2021

A loose nanofiltration membrane fabricated by electrospray interfacial polymerization which contained a tiny amount of sulfonated graphene oxide nanoparticles showed excellent water permeance and salt/dye separation.
The efficient conversion of H2S into mercaptan alcohols mediated in protic ionic liquids under mild conditions
Authors: Xiong Wenjie , Shi Mingzhen , Zhang Xiaomin , Tu Zhuoheng , Hu Xingbang , Wu Youting
Published: September 2021

A novel H2S resource methodology mediated by protic ILs under solvent-free conditions with almost quantitative conversion and fast reaction kinetics.
Development and performance evaluation of a multi-modal optical spectroscopic sensor
Authors: V S Dhanada , Choudhari K. S. , George Sajan D. , Kartha V. B. , Chidangil Santhosh , V K Unnikrishnan
Published: September 2021

Multi-modal optical spectroscopic sensor for complete material characterization.
Synthesis and first-principles study of structural, electronic and optical properties of tetragonal hybrid halobismuthathes [Py2(XK)]2[Bi2Br10−xIx]
Authors: Kotov Vitalii Yu. , Buikin Pert A. , Ilyukhin Andrey B. , Korlyukov Alexander A. , Dorovatovskii Pavel V.
Published: September 2021

Tuning the optical properties of solid solutions by variation of the halogen composition.
Theoretical and experimental study of the influence of PEG and PEI on copper electrodeposition
Authors: Liang Xingyou , Ren Xuefeng , He Runshan , Ma Tingli , Liu Anmin
Published: September 2021

Through theoretical calculation and experimental research, the electrodeposition process of preparing copper catalyst in an acid electrolyte with polyethylene glycol (PEG) and polyethylene imine (PEI) as mixed additives is determined.
Photo- and electro-luminescent properties of 2,7-disubstituted spiro[fluorene-9,9′-xanthene] derivatives containing imidazole-derived moieties
Authors: Ma Hailin , Li Yuanying , Wu Shaoguang , Li Yanmei , Zhao Yuling , Yang Hongyan , Su Wenming , Yu Tianzhi
Published: September 2021

Two spiro[fluorene-9,9′-xanthene]/imidazole-derived moiety hybrid compounds were synthesized for OLED applications.
Visible light-assisted photocatalytic degradation of methylene blue in water by highly chemically stable Cd-coordination polymers at room temperature
Authors: Zhang Feng-Feng , Han You , Liang Qian , Wu Man , Wang Xiao , Tang Long , Yue Er-Lin , Wang Ji-Jiang , Fu Feng , Hou Xiang-Yang
Published: September 2021

Mesoporous YAU-10 based on a binuclear 3D structure has been synthesized as a photocatalytic material exhibiting excellent visible light-assisted degradation of methylene blue.
An efficient treatment of biofilm-induced periodontitis using Pt nanocluster catalysis
Authors: Wu Tao , Sun Jiahui , Lei Jie , Fan Qihang , Tang Xiuyu , Zhu Guixin , Yan Qi , Feng Xiaobo , Shi Bin
Published: September 2021

A Pt nanocluster modified g-C3N4 ointment was developed, showing oxidase-like and peroxidase-like activity, and used for efficient, non-invasive, and antibiotic-free treatment of periodontitis.
Computational study on N-triflylphosphoramide-catalyzed enantioselective hydroamination of alkenyl thiourea
Authors: Takagi Ryukichi , Duong Duyen Thi
Published: September 2021

The mechanism of the enantioselective intramolecular hydroamination of alkenyl thiourea catalyzed by chiral phosphoramide was revealed using density functional theory calculations.
Stress-responsive rhodamine bioconjugates for membrane-potential-independent mitochondrial live-cell imaging and tracking
Authors: Mukherjee Tarushyam , Regar Ramprasad , Soppina Virupakshi , Kanvah Sriram
Published: September 2021

The efficient imaging of mitochondria using cortisol and cholesterol conjugates of rhodamine was demonstrated.
Shape memory-assisted self-healing of dynamic thiol-acrylate networks
Authors: Alabiso Walter , Hron Tiago Manuel , Reisinger David , Bautista-Anguís Daniel , Schlögl Sandra
Published: September 2021

By following shape-memory assisted self-healing (SMASH), we used the shape-memory properties of thiol-acrylate photopolymers to physically close a scratch, whilst chemical healing was obtained via thermo-activated dynamic exchange reactions.
Crosslinked porous polyimides: structure, properties and applications
Authors: Narzary Basiram Brahma , Baker Benjamin C. , Yadav Neha , D'Elia Valerio , Faul Charl F. J.
Published: September 2021

Porous polyimides (pPIs) represent a fascinating class of porous organic polymers (POPs). Here the properties and functions of amorphous and crystalline pPIs are reviewed, and applications contributing to solutions to global challenges highlighted.
Synthesis of a bimetallic metal–organic framework catalyst via selective detection and adsorption of Fe3+ for enhanced bio-based catalysis
Authors: Wang Man , Huang Fangmin , Wang Chan , Hu Yuanyuan , Wu Pengyan , Hu Aonan , Ji Jingwen , Wang Jian
Published: September 2021

A MOF with good chemical resistance exhibits a sensitive fluorescence response and absorbance for Fe3+; Tb-HODA⊃Fe3+ enhances the catalytic efficiency for the dehydration of fructose/glucose into 5-hydroxymethylfurfural.
Tandem Strecker/C(sp3)–H amination reactions for the construction of cyanide-functionalized imidazo[1,5-a]pyridines with NH4SCN as a cyanating agent
Authors: Yang Qing , Yan Xiao-Tong , Feng Cheng-Tao , Chen De-Xiang , Yan Zhong-Zhong , Xu Kun
Published: September 2021

An I2O5-mediated multicomponent reaction that allows the single-step construction of cyano-functionalized imidazo[1,5-a]pyridines with molecular diversity was realized for the first time.
Global opportunities and challenges on net-zero CO2 emissions towards a sustainable future
Authors: Nathanael A. Joseph , Kannaiyan Kumaran , Kunhiraman Aruna K , Ramakrishna Seeram , Kumaravel Vignesh
Published: September 2021

Artistic representation of CO2 emissions from various sources into the atmosphere, and its consequence on the global climatic conditions.
Lipase on carbon nanotubes – an active, selective, stable and easy-to-optimize nanobiocatalyst for kinetic resolutions
Authors: Gal Cristian Andrei , Barabás Laura Edit , Bartha Vári Judith-Hajnal , Moisă Mădălina Elena , Balogh-Weiser Diana , Bencze László Csaba , Poppe László , Paizs Csaba , Toșa Monica Ioana
Published: September 2021

An efficient biocatalyst was obtained by covalent immobilization of lipase B from C. antarctica on functionalized SwCNTs for the kinetic resolution of some aryl-ethanols in batch and continuous-flow modes.
New Cy5 photosensitizers for cancer phototherapy: a low singlet–triplet gap provides high quantum yield of singlet oxygen
Authors: Ma He , Long Saran , Cao Jianfang , Xu Feng , Zhou Panwang , Zeng Guang , Zhou Xiao , Shi Chao , Sun Wen , Du Jianjun , Han Keli , Fan Jiangli , Peng Xiaojun
Published: September 2021

The electron-withdrawing group at the meso-position of Thio-Cy5 could dramatically reduce the singlet–triplet energy gap, and speed up the intersystem crossing process.
Understanding the interplay between the crystal structure and charge transport in alloyed lead-free perovskites
Authors: Boldyreva Aleksandra G. , Sun Shijing , Pierone Polly J. , Talalaev Filipp , Thapa Janak , Hartono Noor Titan Putri , Sher Meng-ju , Buonassisi Tonio , Troshin Pavel A. , Stevenson Keith J.
Published: September 2021

In this study we clarified how crystal structure of Pb-free perovskites affects carrier mobility photosensitivity and photostability.
Effects of aluminum substitution in nickel-rich layered LiNixAl1−xO2 (x = 0.92, 0.95) positive electrode materials for Li-ion batteries on high-rate cycle performance
Authors: Kaneda Haruki , Furuichi Yuki , Ikezawa Atsunori , Arai Hajime
Published: September 2021

Nano-scale Al-rich layers on the surface of LiNi0.92Al0.08O2 and substituted-Al in the crystal suppress both the surface degradation and bulk degradation, resulting in the excellent cycling performance Ni-rich electrode material.
Extraordinary dual-ion electrochemical deionization capacity and energy efficiency enabled by coupling of Na3Fe2(PO4)3 and NiVAl layered double hydroxide electrodes
Authors: Zhang Pei , Yao Lei , Ren Xiangzhong , Li Yongliang , Deng Libo
Published: September 2021

A dual-ion electrochemical deionization system was constructed using NiVAl trimetallic layered double hydroxides as the anode and Na3Fe2(PO4)3 as the cathode to remove NaCl, which exhibited a high desalination capacity and high energy efficiency.
Non-conjugated electrolytes as thickness-insensitive interfacial layers for high-performance organic solar cells
Authors: Yu Yufu , Tao Wuxi , Wang Linqiao , Tao Yang-Dan , Peng Zeyan , Zheng Xiaolong , Xiang Changhao , Zhao Bin , Li Chang-Zhi , Tan Songting
Published: September 2021

PEDETA-DBO has been developed as a thickness-insensitive ETL. The OSCs based on PEDETA-DBO retain more than 92.5% of PCE values at a thickness of 30 nm. The reason for the thickness-insensitive property of non-conjugated ETLs has been revealed.
10 MA cm−2 current density in nanoscale conductive bridge threshold switching selector via densely localized cation sources
Authors: Lin Qi , Feng Jinlong , Yuan Junhui , Liu Long , Eshraghian Jason K. , Tong Hao , Xu Ming , Wang Xingsheng , Miao Xiangshui
Published: September 2021

Super-ionic cation layer was introduced into the CBTS selector to realize ten-fold current density increase.
Accurate prediction of pressure and temperature T1/2 variation in solid state spin crossover by ab initio methods: the [CoII(dpzca)2] case
Authors: Bondì Luca , Brooker Sally , Totti Federico
Published: September 2021

First accurate ab initio prediction of spin crossover (SCO) T1/2 is achieved, for thermal and pressure-active crystalline [CoII(dpzca)2]. The T1/2 is reproduced with extremely low error, <10 K, up to a pressure of 2100 bar.
“Once upon a time...”
Authors: Taylor Mike
Published: September 2021

Representations of data have evolved considerably in the last 20 years: in terms of the scale of the data we have, the ways in which we can communicate and the expectations of our audiences. But as our tools evolve, so we have to evolve our understanding of what we’re doing, the limitations, strengths or weaknesses and how we can use visualization to support our insights and narratives.
The never-ending quest to understand the shapes and motions of molecules
Authors: Baaden Marc
Published: September 2021

Why is it so important to know the shape of molecules? How can virtual reality and advances in scientific visualization help? These are recurrent questions about the importance of understanding molecular shapes and molecular motions. In this brief feature article some background is provided to better understand the central role played by visual and computational analysis of molecular structures. The role of hardware devices and software tools to assist scientists in this quest is pointed out, along with challenges to share visual experiences more broadly. These topics touch upon many current questions in research. Examples related to biological membranes, molecular medicine, -omics data and SARS-Cov-2 structural data are provided to illustrate convincing use cases.
Glucosinolate biosynthesis: role of MAM synthase and its perspectives
Authors: Das Bidyadhar
Published: September 2021

Glucosinolates, synthesized by the glucosinolate biosynthesis pathway, are the secondary metabolites used as a defence mechanism in the Brassicaceae plants, including Arabidopsis thaliana. The first committed step in the pathway, catalysed by methylthioalkylmalate (MAM) synthase (EC: 2.3.3.17), is to produce different variants of glucosinolates. Phylogenetic analyses suggest that possibly MAM synthases have been evolved from isopropylmalate synthase (IPMS) by the substitutions of five amino acid residues (L143I, H167L, S216G, N250G and P252G) in the active site of IPMS due to point mutations. Considering the importance of MAM synthase in Brassicaceae plants, Petersen et al. (2019) made an effort to characterise the MAM synthase (15 MAM1 variants) in vitro by single substitution or double substitutions. In their study, the authors have expressed the variants in Escherichia coli and analysed the amino acids in the cultures of E. coli in vivo. Since modifying the MAM synthases by transgenic approaches could increase the resistance of Brassicaceae plants for enhancing the defence effect of glucosinolates and their degraded products; hence, MAM synthases should be characterized in detail in vivo in A. thaliana along with the structural analysis of the enzyme for meaningful impact and for its imminent use in vivo.
Factors Associated With Hearing Aid Wear Time in a Subset of U.S. Military Veterans: Tinnitus, the Presence of One or More Neurologic Conditions, and Unaided Speech Intelligibility Index
Authors: Giuliani Nicholas P.
Published: September 2021

Purpose:

A retrospective analysis was conducted to explore how tinnitus, one or more neurologic conditions, unaided speech intelligibility index, and other comorbidities impact the average number of hours hearing aids are worn each day by U.S. Military Veterans.

Method:

Medical records and a hearing aid database were queried to obtain information regarding active medical problems and average daily hearing aid wear time. Multiple linear regression was used to explore these relationships for 215 male Veterans whose records were available from 2009 to 2020. To be analyzed, Veterans must have possessed their hearing aid(s) for at least 3 consecutive months.

Results:

An active problem of subjective tinnitus was associated with increased hearing aid wear time (positive association) and one or more active neurologic conditions were associated with decreased hearing aid wear time (negative association). A high unaided speech intelligibility index (greater access to speech sounds without hearing aids) was also associated with decreased hearing aid wear time (negative association).

Conclusions:

There are many complex audiologic and medical concerns that may affect hearing aid wear time in U.S. Military Veterans. Therefore, the information from this study should be expanded on prospectively by further exploring these associations, and their severity, on hearing aid wear time. The information from this and future studies may lead to clinical recommendations with the goal of increasing daily hearing aid use in this and other populations.
Bilateral force sensorless control based on finite‐time adaptive sliding‐mode‐assisted disturbance observer
Authors: Tian Dapeng , Ni Shiquan
Published: September 2021

Bilateral teleoperation systems are widely used to compensate for image spin and in many other applications. Good transparency (position tracking and force feedback) is an important performance index in the control design of bilateral teleoperation systems. This study aims to achieve good transparency for teleoperation systems using force sensorless by proposing an alternative to direct force measurement. Our proposed method is a finite‐time adaptive sliding‐mode‐assisted disturbance observer, which combines disturbance observer with adaptive sliding mode control. The finite‐time stability of adaptive sliding‐mode‐assisted disturbance observer is analysed using the Lyapunov theory. Moreover, a bilateral control law based on adaptive sliding‐mode‐assisted disturbance observer is designed. The proposed method not only improves the system transparency with both force feedback and position tracking, but is also chatter‐free. Experiments are conducted using bilateral brushless DC motors in an experimental setup to demonstrate the effectiveness of the proposed method.
A new method to perform data-model comparison in Fermi-LAT analysis
Authors: Bruel P.
Published: September 2021

Context. The analysis of Fermi-Large Area Telescope (LAT) gamma-ray data in a given Region of Interest (RoI) usually consists of performing a binned log-likelihood fit in order to determine the sky model that after convolution with the instrument response best accounts for the distribution of observed counts.

Aims. While tools are available to perform such a fit, it is not easy to check the goodness-of-fit. The difficulty of the assessment of the data-model agreement is twofold. First of all, the observed and predicted counts are binned in three dimensions (two spatial dimensions and one energy dimension) and comparing two 3D maps is not straightforward. Secondly, gamma-ray source spectra generally decrease with energy as the inverse of the energy square. As a consequence, the number of counts above several GeV generally falls into the Poisson regime, which precludes performing a simple χ2 test.

Methods. We propose a method that overcomes these two obstacles by producing and comparing, at each pixel of the analyzed RoI, spatially integrated count spectra for data and model. The comparison follows a log-likelihood approach that extends the χ2 test to histograms with low statistics. This method can take into account likelihood weights that are used to account for systematic uncertainties.

Results. We optimize the new method so that it provides a fast and reliable tool to assess the goodness-of-fit of Fermi-LAT data and we use it to check the latest gamma-ray source catalog on 10 years of data.
The eROSITA Final Equatorial-Depth Survey (eFEDS)
Authors: Chiu I-Non , Ghirardini Vittorio , Liu Ang , Grandis Sebastian , Bulbul Esra , Emre Bahar Y. , Comparat Johan , Bocquet Sebastian , Clerc Nicolas , Klein Matthias , Liu Teng , Li Xiangchong , Miyatake Hironao , Mohr Joseph , More Surhud , Oguri Masamune , Okabe Nobuhiro , Pacaud Florian , Ramos-Ceja Miriam E. , Reiprich Thomas H. , Schrabback Tim , Umetsu Keiichi
Published: September 2021

We present the first weak-lensing mass calibration and X-ray scaling relations of galaxy clusters and groups selected in the eROSITA Final Equatorial Depth Survey (eFEDS) observed by Spectrum Roentgen Gamma/eROSITA over a contiguous footprint with an area of ≈140 deg2, using the three-year (S19A) weak-lensing data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. In this work, we study a sample of 434 optically confirmed galaxy clusters (and groups) at redshift 0.01 ≲z ≲1.3 with a median of 0.35, of which 313 systems are uniformly covered by the HSC survey to enable the extraction of the weak-lensing shear observable. In a Bayesian population modeling, we perform a blind analysis for the weak-lensing mass calibration by simultaneously modeling the observed count rateηand the shear profileg+of individual clusters through the count-rate-to-mass-and-redshift (η-M500-z) relation and the weak-lensing-mass-to-mass-and-redshift (MWL-M500-z) relation, respectively, while accounting for the bias in these observables using simulation-based calibrations. As a result, the count-rate-inferred and lensing-calibrated cluster mass is obtained from the joint modeling of the scaling relations, as the ensemble mass spanning a range of 1013h-1M⊙≲M500≲ 1015h-1M⊙with a median of ≈1014h-1M⊙for the eFEDS sample. With the mass calibration, we further model the X-ray observable-to-mass-and-redshift relations, including the rest-frame soft-band and bolometric luminosity (LXandLb), the emission-weighted temperatureTX, the mass of intra-cluster mediumMg, and the mass proxyYX, which is the product ofTXandMg. Except forLXwith a steeper dependence on the cluster mass at a statistically significant level, we find that the other X-ray scaling relations all show a mass trend that is statistically consistent with the self-similar prediction at a level of ≲1.7σ. Meanwhile, all these scaling relations show no significant deviation from the self-similarity in their redshift scaling. Moreover, no significant redshift-dependent mass trend is present. This work demonstrates the synergy between the eROSITA and HSC surveys in preparation for the forthcoming first-year eROSITA cluster cosmology.
The cosmic-ray ionisation rate in the pre-stellar core L1544
Authors: Redaelli E. , Sipilä O. , Padovani M. , Caselli P. , Galli D. , Ivlev A. V.
Published: September 2021

Context. Cosmic rays (CRs), which are energetic particles mainly composed of protons and electrons, play an important role in the chemistry and dynamics of the interstellar medium. In dense environments, they represent the main ionising agent, hence driving the rich chemistry of molecular ions. Furthermore, they determine the ionisation fraction, which regulates the degree of coupling between the gas and the interstellar magnetic fields, and the heating of the gas. Estimates of the CR ionisation rate of molecular hydrogen (ζ2) span several orders of magnitude, depending on the targeted sources and on the method used.

Aims. Recent theoretical models have characterised the CR attenuation with increasing density. We aim to test these models for the attenuation of CRs in the low-mass pre-stellar core L1544.

Methods. We used a state-of-the-art gas-grain chemical model, which accepts the CR ionisation rate profile as input, to predict the abundance profiles of four ions: N2H+, N2D+, HC18O+, and DCO+. Non-local thermodynamic equilibrium radiative transfer simulations were run to produce synthetic spectra based on the derived abundances. These were compared with observations obtained with the Institut de Radioastronomie Millimétrique 30 m telescope.

Results. Our results indicate that a model with high ζ2 (>10−16 s−1) is excluded by the observations. Also the model with the standard ζ2 = 1.3 × 10−17 s−1 produces a worse agreement with respect to the attenuation model based on Voyager observations, which is characterised by an average ⟨ ζ2 ⟩ = 3 × 10−17 s−1 at the column densities typical of L1544. The single-dish data, however, are not sensitive to the attenuation of the CR profile, which changes only by a factor of two in the range of column densities spanned by the core model (N = 2−50 × 1021 cm−2). Interferometric observations at higher spatial resolution, combined with observations of transitions with lower critical density – hence tracing the low-density envelope – are needed to observe a decrease in the CR ionisation rate with density.
The impact of massive stars and black holes on the fate of open star clusters and their tidal streams
Authors: Wang Long , Jerabkova Tereza
Published: September 2021

Context. We use present-day observations to investigate how the content of massive OB stars affects the long-term evolution of young open clusters and their tidal streams, and how such an effect influences the constraint of initial conditions.

Aims. OB stars are typically found in binaries. They have a strong wind mass loss during the first few million years and many become black holes. These affect the dynamical evolution of an open star cluster and impact its dissolution in a given Galactic potential. We investigate the correlation between the mass of OB stars and the observational properties of open clusters. Hyades-like star clusters are well represented in the solar neighborhood and thus allow comparisons with observational data.

Methods. We perform a large number of star-by-star numerical N-body simulations of Hyades-like star clusters using the high-performance N-body code PETAR combined with GALPY.

Results. We find that OB stars and black holes have a major effect on star cluster evolution. Star clusters with the same initial conditions but a different initial content of OB stars follow very different evolutionary paths. Thus, the initial total mass and radius of an observed star cluster cannot be unambiguously determined unless the initial content of OB stars is known. We show that the stellar counts in the corresponding tidal tails, which can be identified in the Gaia data, help to resolve this issues. We thus emphasize the importance of exploring not only star clusters but also their corresponding tidal tails. These findings are relevant for studies of the formation of massive stars.
Efficiency of automatic analyses of fish passages detected by an acoustic camera using Sonar5-Pro
Authors: Martignac François , Baglinière Jean-Luc , Ombredane Dominique , Guillard Jean
Published: September 2021

The acoustic camera is a non-intrusive method increasingly used to monitor fish populations. Acoustic camera data are video-like, providing information on fish behaviour and morphology helpful to discriminate fish species. However, acoustic cameras used in long-term monitoring studies generate a large amount of data, making one of the technical limitations the time spent analysing data, especially for multi-species fish communities. The specific analysis software provided for DIDSON acoustic cameras is problematic to use for large datasets. Sonar5-Pro, a popular software in freshwater studies offers several advantages due to its automatic tracking tool that follows targets moving into the detection beam and distinguishes fish from other targets. This study aims to assess the effectiveness of Sonar5-Pro for detecting and describing fish passages in a high fish diversity river in low flow conditions. The tool's accuracy was assessed by comparing Sonar5-Pro outputs with a complete manual analysis using morphological and behavioural descriptors. Ninety-eight percent of the fish moving into the detection beam were successfully detected by the software. The fish swimming direction estimation was 90% efficient. Sonar5-Pro and its automatic tracking tool have great potential as a database pre-filtering process and decrease the overall time spent on data analysis but some limits were also identified. Multi-counting issues almost doubled the true fish abundance, requiring manual operator validation. Furthermore, fish length of each tracked fish needed to be manually measured with another software (SMC). In conclusion, a combination of Sonar5-Pro and SMC software can provide reliable results with a significant reduction of manpower needed for the analysis of a long-term monitoring DIDSON dataset.
Improving the quality of identification and filtering of micro-object images based on neural networks
Authors: Jumanov Isroil , Djumanov Olim , Safarov Rustam
Published: September 2021

Constructive approaches, principles, and models for optimizing the identification of micro-objects have been developed based on the use of combined statistical, dynamic models and neural networks with mechanisms for filtering noise and foreign particles of images of medical objects and pollen grains. Algorithms for learning neural networks under conditions of a priori insufficiency, uncertainty of parameters, and low accuracy of data processing are investigated. The mechanisms of contour selection, segmentation, obtaining the boundaries of segments with hard and soft thresholds, filtering using the morphological features of the image have been developed [1]. Mechanisms for recognition and classification of images, adaptation of parameter values, tuning of the network structure, approximation and smoothing of random emissions, bursts in the image contour are proposed. A mechanism for suppressing impulse noise and noise is implemented based on various filtering methods, preserving the boundaries of objects and small-sized parts. Mathematical expressions are obtained for estimating the identification errors caused by nonstationarity, inadequacy of approximation, interpolation, and extrapolation of the image contour. A software package for the recognition and classification of micro-objects has been developed. The results were obtained for correct, incorrect recognition, as well as rejected pollen samples, which were synthesized with cubic, biquadratic, interpolation spline-functions and wavelet transforms.
Mathematical modeling of heat and mass exchange processes in the evaporative cooler
Authors: Usmonov Nizomjon , Mavjudova Shaxlo , Ivanisova Adeliya
Published: September 2021

This article describes the advantages of the widespread using of the evaporative coolers for cooling recycled wastewater in the air conditioning systems in various industries. The mathematical model of heat and mass transfer processes in the evaporative coolers has been developed. The dependence of the changes in the temperature of the air leaving the evaporator on the irrigation density is considered. When comparing the values obtained by using mathematical expressions and experiments, the resulting difference was 6.7%.
Research of Mechanochemical Processes of Activation of Building Materials by Air-Impact Method
Authors: Kravchenko Igor , Erofeev Mihail , Fedorov Aleksandr , Kondrashchenko Valeriy , Abdumuminova Diana , Yuldashev Shukurilo , Matyokubov Jaloliddin , Bobomurodov Kudrat
Published: September 2021

To increase the specific surface area of the binder and accelerate the strength gain of fast-hardening concrete mixtures, a model has been created for calculating aeroactivators as part of mobile complexes based on new equipment for cement activation, sand enrichment, local materials, and production waste. The proposed model establishes the dependence of the rate of destruction of the dusty shell of particles on the mechanical impact of the beaters and materials` physical and mechanical characteristics. To improve the operational characteristics of the cement aeroactivator, experimental studies were carried out, the results of which made it possible to determine the rational parameters of the developed installation. Based on the test results, it was found that the use of the cement activation process with additives accelerates the hardening process of concrete and mortar mixtures in the initial period, increases the design strength of concretes and mortars by 20–40% in comparison with the strength of the control composition at the same cement consumption, and also reduces the consumption cement up to 17% to obtain concretes and mortars equal to the control composition at the design age.
Refining the Galerkin method error estimation for parabolic type problem with a boundary condition
Authors: Mamatov Alisher , Narjigitov Xusanboy , Turdibayev Dilshod , Rakhmanov Jamshidbek
Published: September 2021

The article considers a parabolic-type boundary value problem with a divergent principal part, when the boundary condition contains the time derivative of the required function: {ut−d/dxiai(x,t,u,∇u)+a(x,t,u,∇u)=0,a0ut+ai(x,t,u,∇u)cos(v,xi)=g(x,t,u,),(x,t)∈St,u(x,0)=u0(x),x∈ΩSuch nonclassical problems with boundary conditions containing the time derivative of the desired function arise in the study of a number of applied problems, for example, when the surface of a body, whose temperature is the same at all its points, is washed off by a well-mixed liquid, or when a homogeneous isotropic body is placed in the inductor of an induction furnace and an electro-magnetic wave falls on its surface. Such problems have been little studied, therefore, the study of problems of parabolic type, when the boundary condition contains the time derivative of the desired function, is relevant. In this paper, the definition of a generalized solution of the considered problem in the space H˜1,1(QT) is given. This problem is solved by the approximate Bubnov-Galerkin method. The coordinate system is chosen from the spaceH1(Ω). To determine the coefficients of the approximate solution, the parabolic problem is reduced to a system of ordinary differential equations. The aim of the study is to obtain conditions under which the estimate of the error of the approximate solution in the normH1(Ω) has orderO(hk−1) The paper first explores the auxiliary elliptic problem. When the condition of the ellipticity of the problem is satisfied, inequalities are proposed for the difference of the generalized solution of the considered parabolic problem with a divergent principal part, when the boundary condition contains the time derivative of the desired function and the solution of the auxiliary elliptic problem. Using these estimates, as well as under additional conditions for the coefficients and the function included in the problem under consideration, estimates of the error of the approximate solution of the Bubnov-Galerkin method in the normH1(Ω) of orderO(hk−1) for the considered nonclassical parabolic problem with divergent principal part, when the boundary condition contains the time derivative of the desired function.
Drip irrigation of the apple orchard in the conditions of Tashkent region in Uzbekistan
Authors: Gulyamov Sardor
Published: September 2021

This article presents the results of long-term theoretical experimental field studies on drip irrigation of Apple orchard of the cultivar “Golden” in the conditions of Tashkent region. Based on the analysis of climate, soil, hydrogeological, hydrological and economic conditions of the experimental plot and biological features of the garden is determined by the values of total water use, scarcity of water, irrigation, irrigation norms and number of irrigations bioclimatic method.
Study of the fabric structure influence on the physical-mechanical and technological properties of knitted products
Authors: Jurabayev Nozimjon , Shogofurov Shakhboz , Kholikov Kurbonali , Meliboev Umarjon
Published: September 2021

Three kinds of knitted fabrics with high shape retention capacity equipment LONG-XING SM 252 (China) 12-grade flat needle loom were produced, their technological characteristics were compared, and graphical records were supplied in this article based on experimental samples of knitted rubber fabric. The developed variants of knitted fabric differ from each other in pattern type, report, shape retention feature and a number of other indicators. Physical and mechanical properties of the obtained samples were determined experimentally on modern equipment installed in the testing laboratory of the Namangan Institute of Engineering Technology.
Development of effective construction and justification of parameters of the cleaner of fibrous material
Authors: Djuraev Anvar , Rosulov Ruzimurad , Kholmirzaev Javlon , Diyorov Husan , Berdimurodov Umid
Published: September 2021

This article provides a general scheme of the principle of operation of a fibrous material cleaner from coarse and fine litter. Based on the compilation of dynamic and mathematical models, its numerical solution, the regularities of the movement of the working bodies of the purifier are presented. Analyzes of the laws of motion and graphic dependencies substantiated the main parameters of the purifier. Recommendations are given for widespread use in fiber-cleaning production.
Theoretical study of the influence of the length of the spike on the cleaning effect of the fine litter cleaner
Authors: Rosulov Ruzimurad , Djuraev Anvar , Diyorov Husan , Berdimurodov Umid
Published: September 2021

In the article, a schematic diagram and principle of operation of the recommended raw cotton cleaner from fine litter are provide. The article presents the results of theoretical studies of the effect of the length of the pegs on the cleaning effect of the raw cotton cleaner. Based on the study of the law of movement of raw cotton on the surface of the splitter, graphical dependences of the change in the length of the splitter on the change in the mass of cotton are constructed. Substantiation of the length of the drum heads of the corresponding areas for cleaning cotton from fine litter.
Enantioselective Palladium-Catalyzed Decarboxylative Dearomative Asymmetric Allylic Alkylation of Benzofurans: Diversity-Oriented Synthesis of Flavaglines
Authors: Lu Hai-Hua , Cao Meng-Yue
Published: September 2021

With the introduction of new Trost-type bisphosphine ligands bearing a chiral cycloalkane framework, the highly efficient and enantioselective palladium-catalyzed decarboxylative dearomative asymmetric allylic alkylation (AAA) of benzofurans was achieved. This enabled a diversity-oriented synthesis (DOS) of previously unreachable flavaglines, which features two diversification stages. A new avenue for developing flavagline-based drugs was thus established.

1 Introduction

2 The Dearomative Asymmetric Allylic Alkylation of Benzofurans

3 Synthesis of Flavaglines

4 Conclusion and Outlook
Synthetic Study on Carthamin, Part 4. Improved Synthesis of a C-Glycosyl Quinochalcone by Installation of a Side Chain through Regioselective De-O-methylation and Acyl Rearrangement
Authors: Ohmori Ken , Suzuki Keisuke , Matsuoka Seiya , Azami Kohei , Fujiki Yusuke , Dohi Reina , Yasuike Tomokazu
Published: September 2021

We report an improved synthesis of a C-Glycosyl quinochalcone that is a key intermediate in our total synthesis of carthamin, a natural red pigment of traditional heritage. The C-glycosyl quinochalcone is prepared by regioselective de-O-methylation of a C-glycosyl bromodienone, and installation of a p-coumaroyl side chain through an O→C acyl rearrangement.
3D Whole-Body MRI of the Musculoskeletal System
Authors: Pasoglou Vassiliki , Van Nieuwenhove Sandy , Peeters Frank , Duchêne Gaetan , Kirchgesner Thomas , Lecouvet Frederic E.
Published: September 2021

With its outstanding soft tissue contrast, spatial resolution, and multiplanar capacities, magnetic resonance imaging (MRI) has become a widely used technique. Whole-body MRI (WB-MRI) has been introduced among diagnostic methods for the staging and follow-up assessment in oncologic patients, and international guidelines recommend its use. In nononcologic applications, WB-MRI is as a promising imaging tool in inflammatory diseases, such as seronegative arthritis and inflammatory myopathies. Technological advances have facilitated the introduction of three-dimensional (3D) almost isotropic sequences in MRI examinations covering the whole body. The possibility to reformat 3D images in any plane with equal or almost equal resolution offers comprehensive understanding of the anatomy, easier disease detection and characterization, and finally contributes to correct treatment planning. This article illustrates the basic principles, advantages, and limitations of the 3D approach in WB-MRI examinations and provides a short review of the literature.
3D MRI of the Spine
Authors: Sahr Meghan , Tan Ek Tsoon , Sneag Darryl B.
Published: September 2021

Three-dimensional (3D) magnetic resonance imaging of the spine is now clinically feasible due to technological advancements. Its advantages over two-dimensional imaging include higher in-plane spatial resolution and the ability for reformation in any plane that enables time savings in image acquisition and aids more accurate interpretation. Multispectral 3D techniques for imaging around metal are sometimes useful for evaluating anatomy adjacent to spinal fixation hardware. 3D gradient-recalled echo sequences, including ultrashort or zero time to echo sequences, can provide osseous detail similar to conventional computed tomography.
3D MRI of the Ankle: A Concise State-of-the-Art Review
Authors: Fritz Benjamin , Fritz Jan , Sutter Reto
Published: September 2021

Magnetic resonance imaging (MRI) is a powerful imaging modality for visualizing a wide range of ankle disorders that affect ligaments, tendons, and articular cartilage. Standard two-dimensional (2D) fast spin-echo (FSE) and turbo spin-echo (TSE) pulse sequences offer high signal-to-noise and contrast-to-noise ratios, but slice thickness limitations create partial volume effects. Modern three-dimensional (3D) FSE/TSE pulse sequences with isotropic voxel dimensions can achieve higher spatial resolution and similar contrast resolutions in ≤ 5 minutes of acquisition time. Advanced acceleration schemes have reduced the blurring effects of 3D FSE/TSE pulse sequences by affording shorter echo train lengths. The ability for thin-slice partitions and multiplanar reformation capabilities eliminate relevant partial volume effects and render modern 3D FSE/TSE pulse sequences excellently suited for MRI visualization of several oblique and curved structures around the ankle. Clinical efficiency gains can be achieved by replacing two or three 2D FSE/TSE sequences within an ankle protocol with a single isotropic 3D FSE/TSE pulse sequence. In this article, we review technical pulse sequence properties for 3D MRI of the ankle, discuss practical considerations for clinical implementation and achieving the highest image quality, compare diagnostic performance metrics of 2D and 3D MRI for major ankle structures, and illustrate a broad spectrum of ankle abnormalities.
3D MRI of the Hand and Wrist: Technical Considerations and Clinical Applications
Authors: Dalili Danoob , Fritz Jan , Isaac Amanda
Published: September 2021

In the last few years, major developments have been observed in the field of magnetic resonance imaging (MRI). Advances in both scanner hardware and software technologies have witnessed great leaps, enhancing the diagnostic quality and, therefore, the value of MRI. In musculoskeletal radiology, three-dimensional (3D) MRI has become an integral component of the diagnostic pathway at our institutions. This technique is particularly relevant in patients with hand and wrist symptoms, due to the intricate nature of the anatomical structures and the wide range of differential diagnoses for most presentations. We review the benefits of 3D MRI of the hand and wrist, commonly used pulse sequences, clinical applications, limitations, and future directions. We offer guidance for enhancing the image quality and tips for image interpretation of 3D MRI of the hand and wrist.