bluuebunny/crossref_metadata_2025 huggingface dataset:
The Galactic latitude dependency of Faraday complexity in the S-PASS/ATCA RM catalogue
Authors: Ranchod S. , Mao S. A. , Deane R. , Sridhar S. S. , Damas-Segovia A. , Livingston J. D. , Ma Y. K.
Published: March 2024

The S-band Polarisation All Sky Survey (SPASS/ATCA) rotation measure (RM) catalogue is the largest broadband RM catalogue to date, increasing the RM density in the sparse southern sky. Through analysis of this catalogue, we report a latitude dependency of the Faraday complexity of polarised sources in this catalogue within 10° of the Galactic plane towards the inner Galaxy. In this study, we aim to investigate this trend with follow-up observations using the Australia Telescope Compact Array (ATCA). We observe 95 polarised sources from the SPASS/ATCA RM catalogue at 1.1–3.1 GHz with ATCA’s 6 km configuration. We present Stokes QU fitting results and a comparative analysis with the SPASS/ATCA catalogue. We find an overall decrease in complexity in these sources with the higher angular resolution observations, with a complexity fraction of 42%, establishing that the majority of the complexity in the SPASS/ATCA sample is due to the mixing-in of diffuse Galactic emission at scales θ > 2.8′. Furthermore, we find a correlation between our observed small-scale complexity θ < 2.8′ and the Galactic spiral arms, which we interpret to be due to Galactic turbulence or small-scale polarised emission. These results emphasise the importance of considering the maximum angular scale to which the observations are sensitive in the classification of Faraday complexity; the effect of which can be more carefully investigated with SKA-precursor and pathfinder arrays (e.g. MeerKAT and ASKAP).
Thermal structure of circumbinary discs: Circumbinary planets should be icy, not rocky
Authors: Pierens Arnaud , Nelson Richard P.
Published: March 2024

The process of forming a circumbinary planet is thought to be intimately related to the structure of the nascent circumbinary disc. It has been shown that the structure of a circumbinary disc depends strongly on three-dimensional effects and on detailed modelling of the thermodynamics. Here, we employ three-dimensional hydrodynamical simulations, combined with a proper treatment of the thermal physics using the RADMC-3D radiation transport code, to examine the location of the snow line in circumbinary discs. The models have application to the circumbinary planets that have been discovered in recent years by the Kepler and TESS transit surveys. We find that the snow line is located in a narrow region of the circumbinary disc, close to the inner cavity that is carved out by the central binary, at typical orbital distances of ~ 1.5–2 au for the system parameters considered. In this region, previous work has shown that both grain growth and pebble accretion are likely to be inefficient because of the presence of hydrodynamical turbulence. Hence, in situ planet formation interior to the snow line is unlikely to occur and circumbinary planets should preferentially be icy, not rocky.
Some existence theorems on path-factor critical avoidable graphs
Authors: Zhou Sizhong , Liu Hongxia
Published: March 2024

A spanning subgraph F of G is called a path factor if every component of F is a path of order at least 2. Let k ≥ 2 be an integer. A P≥k-factor of G means a path factor in which every component has at least k vertices. A graph G is called a P≥k-factor avoidable graph if for any e ∈ E(G), G has a P≥k-factor avoiding e. A graph G is called a (P≥k, n)-factor critical avoidable graph if for any W ⊆ V (G) with |W| = n, G − W is a P≥k-factor avoidable graph. In other words, G is (P≥k, n)-factor critical avoidable if for any W ⊆ V (G) with |W| = n and any e ∈ E(G − W ), G − W − e admits a P≥k-factor. In this article, we verify that (i) an (n + r + 2)-connected graph G is (P≥2, n)-factor critical avoidable if I(G)>(n+r+2)/(2(r+2)) ; (ii) an (n + r + 2)-connected graph G is (P≥3, n)-factor critical avoidable if t(G)>(n+r+2)/(2(r+2)) ; (iii) an (n + r + 2)-connected graph G is (P≥3, n)-factor critical avoidable if I(G)>(n+3(r+2))/(2(r+2)) ; where n and r are two nonnegative integers.
Adipositas mit depressiver Komponente
Authors: Nickel Anja
Published: March 2024

Die Ernährungsberatung von Übergewichtigen ist langwierig. Rückschläge müssen
verdaut werden. Kommt dann noch eine depressive Erkrankung mit Antriebsarmut
hinzu, kann das Einzelcoaching der bessere Weg sein als ein Gruppensetting. Ein
Fallbericht.
Essstörungen und psychische Komorbidität
Authors: Mühleck Julia , Wick Katharina , Berger Uwe
Published: March 2024

Essstörungen zählen zu den schwerwiegendsten psychischen Erkrankungen bei
Jugendlichen und jungen Erwachsenen. Eine frühzeitige und exakte Diagnostik
sichert den Behandlungserfolg. Die Diagnostik ist jedoch u. a. erschwert durch
Mischformen, unklare Formen und eine hohe Rate an Komorbiditäten. Wir berichten
anhand eines klinischen Fallbeispiels über eine besondere Form der Komorbidität,
die erst seit wenigen Jahren genauer erforscht wird.
Synthesis of N-Trifluoromethyl Thiocarbamates and Ureas from 3-Aminopyridine-Derived Carbamates
Authors: Liu Jianbo , He Xingjin , Deng Linbei , You Ying , Lai Yongxing
Published: March 2024

The synthesis of N-trifluoromethyl thiocarbamates and ureas from 3-pyridyl isothiocyanates via the nucleophilic substitution reaction of perfluorophenyl pyridin-3-yl(trifluoromethyl)carbamate is described. Recently, Schoenebeck’s group reported a straightforward method to access N-trifluoromethyl analogues of amides and related carbonyl compounds. However, N-trifluoromethyl thiocarbamates and ureas derived from pyridine-containing amines remain a synthetic challenge. In this paper, the strategy relies on the operationally simple preparation of perfluorophenyl pyridin-3-yl(trifluoromethyl)carbamates, which can smoothly undergo nucleophilic substitution reactions with thiophenol, sodium mercaptide, and amine. Various functional groups such as amide, halogen, ether, and ester were tolerated under these reaction conditions. Notably, alkylamine structures containing pyridine heterocyclic rings are also compatible to access N-trifluoromethyl thiocarbamates.
Diazananographene with Quadruple [5]Helicene Units: Synthesis, Optical Properties, and Supramolecular Assembly
Authors: Ma Xiao-Hui , Xing Jiang-Feng , Chai Ling , Deng Qing-Song , Chen Xuan-Wen , Su Hai-Feng , Li Chao , Tan Yuan-Zhi
Published: March 2024

A helical diazananographene (1) was successfully synthesized by employing sterically hindered t-butyl groups to inhibit further dehydrocyclization of [5]helicene units. These t-butyl groups stabilized the conformation of [5]helicene units, thus resulting in three stable conformers of 1, comprising a pair of enantiomers (1-(P, P, P, P) and 1-(M, M, M, M)) and a mesomer (1-(P, P, M, M)). In comparison to its planar analogs, helical 1 exhibited broadened peaks in both its absorption and emission spectra, leading to an increase in the emission quantum yield from 0.3 to 0.6. The significantly enhanced radiative decay rate (k
r) accounted for the increase in the quantum yield of 1. Additionally, it was observed that the compound could be fully protonated upon the addition of an equivalent acid. Furthermore, 1 assembled into a chiral trimeric metallosupramolecular complex upon coordination with the PdII units. Both protonated 1 and the metallosupramolecular complex exhibited an enhanced circular dichroic response. These findings revealed that the incorporation of a helical structure and pyridinic nitrogen-doping into the nanographene can allow the synthesis of responsive chiroptical graphenic materials, which could serve as fundamental components for constructing chiral hierarchical metallosupramolecular structures.
Stereospecific Palladium-Catalyzed Cross-Coupling of Alkylboron Compounds: A Short Account
Authors: Lee Hong Geun , Roh Byeongdo
Published: March 2024

Stereospecific approaches allow the introduction of a stereogenic center into complex organic molecules using optically active reagents. Among these, the Pd-catalyzed stereospecific cross-coupling of chiral alkylboron compounds stands out as a highly effective tool for organic synthesis. In parallel with advances in the development of borylation technology, the strategy has recently witnessed a growth in its applicability. This account aims to review the progress on Pd-catalyzed stereospecific B-alkyl Suzuki–Miyaura cross-coupling, tracing its evolution from early breakthroughs to the most recent advances.

1 Introduction

2 Cross-Coupling of 1° Alkylboron Compounds

3 Cross-Coupling of Benzylboron Compounds

4 Cross-Coupling of Allyl- and Propargylboron Compounds

5 Cross-Coupling of Other Types of Activated 2° Alkylboron Compounds

6 Cross-Coupling of Unactivated 2° Alkylboron Compounds

7 Conclusion and Outlook
A Simple Tool to Benchmark Reactivity in Asymmetric Catalysis
Authors: Rovis Tomislav , Muñoz Alberto
Published: March 2024

Herein, we report a simple and noninvasive experimental protocol in which a series of relative reaction rates may be obtained by way of single competition experiments. This approach permits a quantitative comparison of any given number of chiral catalysts relative to a ‘benchmarking’ chiral catalyst – a particularly useful tool since catalyst design and selection have remained largely dependent on chemical intuition. We apply this benchmarking approach towards an asymmetric N-heterocyclic carbene (NHC) catalyzed intramolecular Stetter reaction as a proof-of-concept study. In doing so, we demonstrate a rapid method to assess the complex interplay between catalyst reactivity and stereoelectronic effects – an analytical approach that has heretofore not been attempted for NHCs. To showcase the generality of this method, we apply it to an enantioselective Rh(I)-catalyzed [2+2+2] cycloaddition of alkenyl isocyanates and aryl alkynes for a series of chiral phosphoramidite ligands. The results described herein demonstrate that this inexpensive and easily adoptable protocol can reveal complex yet subtle steric and stereoelectronic effects of vastly different chiral catalyst structures, which can further aid with catalyst development and selection for a clearly defined application.
The Electrochemical trans-Chloroformyloxylation of Unactivated Alkenes
Authors: Queder Jona , Hilt Gerhard
Published: March 2024

An attempted aryl selenium-catalyzed formation of cis-chlorohydrins from alkenes was unsuccessful but led to an electrochemical investigation for the trans-selective chloroformyloxylation of cyclic and acyclic alkenes in moderate to good yields. Interestingly, when 1,1-disubstituted alkenes were used, the corresponding vinyl chloride derivatives were obtained, and the application of 1-phenylcyclohex-1-ene led to the formation of an allyl chloride derivative.
SFM Fetal Therapy Practice Guidelines: Fetal Shunts
Authors: Manikandan K. , Bhatt Reema
Published: March 2024

Fetal shunt is placed into the fetus in order to drain fluid from a fluid-filled fetal area into the amniotic cavity. The main indications are hydrothorax, congenital pulmonary airway malformation (CPAM) with dominant cyst, and lower urinary tract obstruction.

Fetal shunt is indicated if the hydrothorax is primary or hypertensive. In case of re-accumulation after a diagnostic tap or if the primary hydrothorax has led to a secondary nonimmune hydrops provided the primary nature is clearly established and in cases where gestational age is less than 34 weeks.

A shunt in CPAM is indicated in case of CPAM with a dominant cyst where the CPAM volume ratio (CVR) is greater than 1.6, where macrocysts are visible within the lesion, where the diameter of the dominant cyst is more than one-third of the largest diameter of the lesion and where presence of hydrops is not a contraindication for shunting. In case of lower urinary tract obstruction, fetal shunt may be indicated if the following conditions are met. The etiology of lower urinary tract obstruction is posterior urethral valve with oligohydramnios and fetal urinalysis is favorable.
Eficácia da ressonância magnética dinâmica no diagnóstico da mielopatia cervical degenerativa: Protocolo de revisão sistemática*
Authors: Luizari Vanessa Pereira Gil , Oliveira Lorena Pereira dos Reis , Pontes Mariana Demétrio de Sousa , Soeira Thabata Pasquini , Herrero Carlos Fernando Pereira da Silva
Published: March 2024

A mielopatia cervical degenerativa (MCD) é uma doença da coluna cervical com manifestações clínicas de compressão da medula espinal relacionadas ao estreitamento crônico, não traumático e progressivo do canal vertebral cervical. A ressonância magnética (RM) convencional é o exame padrão-ouro para o diagnóstico e a avaliação da gravidade da MCD. Contudo, o paciente encontra-se em posição neutra e estática durante a realização deste exame, o que pode desvalorizar os fatores dinâmicos da MCD, subestimando o risco de lesão medular relacionados aos movimentos de flexão e extensão da coluna cervical. A RM dinâmica é uma técnica promissora para modificar esse panorama. Portanto, a presente revisão tem o objetivo de responder a seguinte pergunta: “A RM dinâmica da coluna cervical é mais precisa no diagnóstico de MCD em comparação à RM convencional?” As buscas por estudos serão realizadas nas bases de dados MEDLINE (via PubMed), Embase, Scopus, Web of Science, LILACS e SciELO. A estratégia de busca conterá combinação de termos relacionados à mielopatia cervical e à ressonância magnética. Dois avaliadores independentes irão realizar a seleção dos estudos, a extração dos dados e a avaliação dos riscos de viés. A síntese dos resultados será realizada de maneira descritiva, considerando os principais achados dos estudos relacionados aos desfechos de interesse.
Um joelho com deficiência de ligamento cruzado anterior e alto grau no teste de pivot shift deve apresentar aumento de rotação interna?
Authors: Lima Luiz Henrique Pires de , Gomes João Luiz Ellera
Published: March 2024

Objetivo: A ruptura do ligamento cruzado anterior (LCA) é uma das lesões mais comuns em atletas e está frequentemente associada a danos nas estruturas anterolaterais. Esta combinação de lesões apresenta-se clinicamente como um teste de pivot shift de alto grau. A hipótese deste estudo é que pacientes com deficiência de LCA e teste de pivot shift de alto grau tenham aumento da rotação interna (RI) do joelho.

Métodos: Vinte e dois pacientes foram testados. Após raquianestesia efetiva, foram realizados dois testes com o paciente em posição supina. Primeiro, o teste de pivot shift bilateral foi realizado manualmente e seu grau foi registrado. Em seguida, com o joelho flexionado a 90 graus, o examinador traçou a projeção do pé em posição neutra e em RI máxima e mediu o ângulo de RI a partir dos eixos construídos entre o ponto central do calcanhar e o hálux.

Resultados: Joelhos com deficiência de LCA apresentam delta da RI média estatisticamente significativo de 10,5 graus entre os grupos sem ajuste de idade e de 10,6 graus com ajuste de idade.

Conclusões: Joelhos com deficiência do LCA e teste de pivot shift de grau I não apresentam aumento da RI em relação aos joelhos com LCA íntegro. Joelhos com deficiência do LCA e teste de pivot shift de graus II e III apresentam RI em comparação aos joelhos saudáveis.
Comparação entre os testes DN4 e DN4 interview na identificação de dor neuropática após cirurgia de fraturas
Authors: Waldolato Gustavo , Pereira Glauciana de Sousa , Carvalho Isabela Storch , Polese Janaine Cunha , Leopoldino Amanda Aparecida Oliveira
Published: March 2024

Objetivo: Comparar os resultados obtidos através do questionário DN4 com os do DN4i com aplicação via telefônica na identificação de dor neuropática após cirurgia de fraturas.

Métodos: Este foi um estudo metodológico com questionário aplicado presencialmente (DN4) e por telefone (DN4i). Foram elegíveis os participantes maiores de 18 anos de idade submetidos à cirurgia de fraturas em um hospital universitário no período de janeiro de 2017 a julho de 2020, que assinaram o Termo de Consentimento Livre e Esclarecido (TCLE) e puderam comparecer ao departamento de Ortopedia e Traumatologia do hospital. A concordância entre a pontuação total obtida na aplicação presencial e por telefone foi avaliada por meio do coeficiente de correlação de Pearson. O coeficiente de Kappa foi utilizado para avaliar a concordância entre os itens individuais dos questionários.

Resultados: Dos 53 participantes, 50 apresentaram resultado igual para rastreio de dor neuropática em relação ao DN4 com o DN4i, sendo 41 com escore positivo para dor neuropática e 12 com escore negativo. O coeficiente de correlação de Pearson e o coeficiente Kappa apresentaram r = 0.84.

Conclusão: O uso telefônico do DN4i comparado à aplicação presencial do DN4 apresenta forte concordância tanto entre os itens individuais dos questionários quanto entre a pontuação total obtida.
Effect of sputtering working pressure on the reliability and performance of amorphous indium gallium zinc oxide thin film transistors
Authors: Lee Taeho , Park Jin-Seok , Oh Saeroonter
Published: March 2024

In this study, the reliability and electrical properties of indium gallium zinc oxide (IGZO) thin film transistors (TFTs) are investigated when the working pressure of the sputtering system is varied. As IGZO is deposited at a low working pressure, the sputtering yield increases and the film density increases from 5.84 to 6.00 g/cm3 based on x-ray reflectivity measurements. IGZO TFT sputtered at low working pressure has a mobility of 8.05 cm2/V s, a threshold voltage of 1.25 V, and a subthreshold swing of 0.25 V/dec. In addition, x-ray photoelectron spectroscopy analysis shows that the oxygen content in the film decreases when IGZO is deposited at a low working pressure, resulting in improved positive bias stress reliability due to the oxygen-poor film. Furthermore, the IGZO film deposited at a low working pressure effectively prevents the formation of defects caused by the environment such as H2O molecules.
Phase-field modeling of ATG instability in Allen–Cahn framework
Authors: Chen Xuyang , Li Guangchao , Lin Feng
Published: March 2024

The phenomenon of Asaro–Tiller–Grinfeld (ATG) instability is common in the molecular beam epitaxy (MBE) process. In order to investigate the ATG instability, a two-dimensional mathematical model is established, which considers elastic stress. The phase-field method is utilized to simulate the interface evolution and the stress distribution. Furthermore, the Allen–Cahn approach, coupled with the motion of the interface, is used to investigate the morphology evolution. The results show that the thin film becomes unstable when it reaches a critical value. The critical thickness of the thin film is about 5.08 nm. The interface breaks into several parts due to the effect of elastic stress. The validity and correctness of the model are verified by the relevant theoretical results. Moreover, the numerical model can provide the basis for optimizing the ATG instability phenomenon in the MBE process.
Rapid and automatic phenotyping of cells through their annexin-mediated enforced blebbing response
Authors: Huang Wei , Wang Zheng , Au Dennis WY , Tang Bingxian , Qi Baiqian , Cho William C. , Lin Yuan
Published: March 2024

Cellular blebbing has been widely recognized as a hallmark of processes such as apoptosis and cell migration. Here, we developed a novel double-layer compression microfluidic device to trigger the enforced blebbing of cells in a programmable manner. It was found that the critical compression for inducing membrane bleb in highly invasive or drug-resistant breast and lung cancer cell lines could be several times higher than that of their non-invasive or drug-sensitive counterparts. Furthermore, we showed that knockdown of annexin-6, a protein known to be heavily involved in membrane and calcium dynamics in cells, led to a significantly reduced cellular volume, reflecting a lowered intracellular pressure, and an ∼twofold increase in the critical compressive strain for triggering blebbing. The fact that hundreds of cells can be tested and automatically analyzed in our device at the same time highlights the potential of this simple and label-free method in applications such as cell sorting and disease detection.
Enhanced sensitivity to target offset when using cross-beam energy transfer mitigation techniques in direct-drive inertial confinement fusion implosions
Authors: Anderson K. S. , Marozas J. A. , Collins T. J. B. , Forrest C. J. , Goncharov V. N. , Cao D.
Published: March 2024

In direct-drive inertial confinement fusion, target offset from the target chamber center (or center of beam convergence) may lead to significant implosion asymmetry and fusion yield degradation. In addition, cross-beam energy transfer (CBET) has been shown to be a significant source of laser energy scattering and leads to a reduction in implosion velocity and yield. To improve energy coupling and implosion performance, several techniques for CBET mitigation have been proposed. Recent simulations, however, have shown that CBET also substantially mitigates the effect of target offset on implosion asymmetry and yield [Anderson et al., Phys. Plasmas 27, 112713 (2020)]. Furthermore, the inclusion of CBET models in radiation-hydrodynamics codes was shown to greatly improve agreement between simulations and experiments involving substantial target offset distances. This paper explores the intensity dependence of this CBET–offset effect. In addition, it is shown that enhanced sensitivity to target offset can be expected when CBET-mitigation techniques are used in direct-drive implosions. This is shown through simulations of two such CBET-mitigation techniques on the OMEGA laser: (1) decreased beam-to-target radius, and (2) beam-to-beam frequency detuning. For the typical target offset distances (<15 μm) observed in experiments on OMEGA, however, overall yield is still anticipated to be substantially higher when CBET-mitigation techniques are employed.
Probabilistic learning approach for the liquid holdup analysis of high-viscosity intermittent flows
Authors: Guzmán J. E. V. , González-Treviño J. A. , Torres L. , Aragón-Rivera F. , Hernández-García J. , Palacio-Pérez A. , Klapp J.
Published: March 2024

A Gaussian mixture model (GMM) was implemented to investigate the relationship between the liquid holdup (in various parts of the flow) and the pressure for different experimental realizations of high-viscosity gas–liquid flows. We considered a Newtonian fluid with a constant viscosity of 6 Pa s (600 cP) under a laboratory-controlled temperature. Because the pressure and the holdup do not exhibit a clear-cut relationship in the time domain, a supervised classification algorithm and a “deep” neural network (DNN) were first applied to classify the data points and predict average holdup values. Then, the GMM was applied to determine the holdup in various liquid aggregation structures of the flow as a function of the pressure. The growth rates of the cumulative lengths of the liquid structures (i.e., slug body, mixing front, and liquid film) and the gas bubbles were obtained. The GMM predicted holdup values were in close agreement with the experimental data.
Nonlinear motion characteristics of the high-temperature superconducting levitation system with boundary crack
Authors: Li Hui , Huang Yi
Published: March 2024

High-temperature superconducting levitation systems have nonlinear behaviors, such as the period-doubling bifurcation and chaotic vibration under external excitation, in connection with the nonlinear hysteresis interaction between the high-temperature superconductors (HTSC) and permanent magnet. The HTSC is a non-ideal type II superconductor in which the fracture is generated internally during manufacturing, and the material properties are brittle. The HTSC tends to crack under a strong magnetic field and electromagnetic force, and its internal defects are likely to cause structural damage with the variable Lorentz force. The fracture performance of the superconducting magnetic levitation system will affect the temperature variation of HTSC, in which the temperature is coupled with the internal electromagnetic force. In this paper, we analyze the fracture characteristics of the HTSC in nonlinear vibration with thermal effect. A superconducting magnetic levitation system model with boundary cracks is applied to study the coupling of multiple physical fields in dynamic processes. The Maxwell equation and superconducting electromagnetic constitutive equation are used to obtain the superconductor’s current density, and the temperature is calculated through the heat conduction equation. The superconducting magnetic flux flow and creep model is applied to analyze the magnetic flux motion inside the superconductors. We compare the superconducting levitation system’s electromagnetic force, temperature, and current density with four critical current densities. The numerical results show that the critical current density of superconductors significantly impacts bifurcation motion, and the temperature of the crack tip of the superconductors varies greatly during vibration, causing the superconductor to lose its superconductivity.
A new Stroh formalism for gradient
electro-mechanics with applications
to Lamb waves in piezoelectric and
flexoelectric coupled plates
Authors: Zhu Feng , Li Nian , Pan Ernian , Qu Yilin
Published: March 2024

In this paper, a new Stroh formalism for gradient electro-mechanics is derived for the first time, which is both mathematically concise and numerically powerful, applicable to generally coupled anisotropic material systems. Based on this new formalism, the complicated Lamb wave in flexoelectric and piezoelectric plates is investigated. The dispersion equation is obtained by solving the eigenvalue problem along with the unconditionally stable dual-variable and position method. From the obtained dispersion equation, the dispersion curves and mode shapes of the Lamb wave are calculated by the 1D form of the multidimensional moduli ratio convergence method. Two important and interesting features are observed from our analysis: One is the difference in the mode shape symmetry between the piezoelectric and flexoelectric cases, and the other is the size-dependent property of the flexoelectric effect as observed by nondimensionalization. These features are further illustrated by comparing the dispersion curves and wave-mode shapes among the three different material models (purely piezoelectric, purely flexoelectric, and flexoelectric and piezoelectric coupled). The newly derived Stroh formalism offers a robust, concise, and unified approach for dealing with strain gradient electro-mechanic materials with crystal systems of general anisotropy. The present work also explains the physical mechanism of symmetry breaking observed, as induced by flexoelectric coupling in piezoelectric materials.
CREST—A program for the exploration of low-energy molecular chemical space
Authors: Pracht Philipp , Grimme Stefan , Bannwarth Christoph , Bohle Fabian , Ehlert Sebastian , Feldmann Gereon , Gorges Johannes , Müller Marcel , Neudecker Tim , Plett Christoph , Spicher Sebastian , Steinbach Pit , Wesołowski Patryk A. , Zeller Felix
Published: March 2024

Conformer–rotamer sampling tool (CREST) is an open-source program for the efficient and automated exploration of molecular chemical space. Originally developed in Pracht et al. [Phys. Chem. Chem. Phys. 22, 7169 (2020)] as an automated driver for calculations at the extended tight-binding level (xTB), it offers a variety of molecular- and metadynamics simulations, geometry optimization, and molecular structure analysis capabilities. Implemented algorithms include automated procedures for conformational sampling, explicit solvation studies, the calculation of absolute molecular entropy, and the identification of molecular protonation and deprotonation sites. Calculations are set up to run concurrently, providing efficient single-node parallelization. CREST is designed to require minimal user input and comes with an implementation of the GFNn-xTB Hamiltonians and the GFN-FF force-field. Furthermore, interfaces to any quantum chemistry and force-field software can easily be created. In this article, we present recent developments in the CREST code and show a selection of applications for the most important features of the program. An important novelty is the refactored calculation backend, which provides significant speed-up for sampling of small or medium-sized drug molecules and allows for more sophisticated setups, for example, quantum mechanics/molecular mechanics and minimum energy crossing point calculations.
Dichotomy of the description of the elastic and electronically inelastic scattering of electrons by methane
Authors: Randi P. A. S. , Moreira G. M. , da Costa R. F. , Bettega M. H. F.
Published: March 2024

The interaction between electrons and methane is studied with a particular focus on describing the dynamics of elastic and electronic excitation processes under the influence of the multichannel coupling effects. Elastic and electronically inelastic integral and differential cross sections are reported. These cross sections were calculated with the Schwinger multichannel method implemented with norm-conserving pseudopotentials within the minimal orbital basis for single-configuration interaction approach with up to 181 open channels. While an excellent agreement with previously published data is found in the elastic channel, the comparisons involving electronic excitation cross sections reveal significant discrepancies. Furthermore, the lack of reliable experimental data regarding the electronically inelastic channels hampers a more detailed analysis of the theoretical results. Additionally, total ionization and total cross sections for electron collisions with methane are also presented. By highlighting the current theoretical challenges in dealing with electron-induced electronic excitation of molecules, we seek to contribute to a deeper understanding of this scattering process and, thus, pave the way for future research.
A sectional method to estimate the transmission coefficients of a new type pile-supported permeable breakwater
Authors: Pan Xinying , Wu Dan , Liang Bingchen , Wu Guoxiang
Published: March 2024

This article investigates the transmission coefficient of a novel pile-supported permeable breakwater featuring inclined porous plates under regular waves. To analyze the transmission coefficient, we propose a sectional method that involves multiplying the transmission coefficients of three distinct sections: the upper retaining wall and porous plates, the horizontal platform, and the piles. The calculation employs the eigenfunction expansion method and empirical formula for pile-supported breakwaters. This method is applicable for water levels that fall between the upper and lower edges of the horizontal platform. The analytical results are compared with experimental tests and show good agreement. Further analysis reveals that the transmission coefficient is significantly influenced by the increasing length of the horizontal platform. Moreover, it is observed that the effect of porosity ε is not particularly noticeable when ε>20%.
Investigation of cavitation shedding mechanisms including reentrant jet and shock wave by Eulerian–Lagrangian multiscale simulation
Authors: Li Linmin , Cheng Xiang , Zhu Zuchao , Sun Xun , Zhang Xinglin
Published: March 2024

Sheet-to-cloud cavitation in a Venturi pipe is investigated experimentally and numerically in this work. The multiscale vapor structures are simulated by Eulerian–Lagrangian multiscale modeling. The volume of fluid method with adaptive mesh refinement is employed to capture the macroscale cavity features, utilizing the large eddy simulation approach. The results of mesh sensitivity study demonstrate that second-order refinement is capable of capturing phase details and cavitation shedding behaviors. A comparison with experimental results reveals the mechanisms of different types of cavitation shedding induced by reentrant jet and shock wave. Taking microscale bubbles into account using the Lagrangian approach and achieving Eulerian–Lagrangian coupling, the multiscale cavitation features, including the morphological evolution of large cavities and characteristics of microbubbles, are accurately reproduced. The evolution features of microbubbles during pressure wave or condensation shock propagation are well recognized by different changing rates. The results indicate that shedding mechanisms in Venturi pipe cavitation can be categorized into three types: reentrant jet, condensation shock, and pressure wave. In the three conditions investigated in this work, shedding cycles are found to be mainly induced by the reentrant jet (σ = 1.03), reentrant jet, condensation shock, and pressure wave (σ = 0.64), and condensation shock (σ = 0.39), respectively, with a decrease in the cavitation number.
Carbon nanotube–cesium tungsten oxide–poly(N-isopropylacrylamide) hydrogel-based optical writing display
Authors: Yang Jonguk , Ju Sanghyun
Published: March 2024

Studies have attempted to improve thermal conductivity by complexing polymers. Via the complexing of photothermal materials with a heat-sensitive polymer, heat can be generated internally, thus resulting in efficient changes in the properties of the heat-sensitive polymer. This study fabricated an optical writing display to locally induce heat generation in poly(N-isopropylacrylamide) (pNIPAM), which is a heat-responsive material, using the photothermal effect of a near-infrared (NIR) absorbing material. Cesium tungsten oxide (CTO), an NIR-absorbing material, exhibits excellent properties due to its photothermal properties. By mixing carbon nanotubes (CNTs), the photothermal effect caused by NIR rays was strengthened and was more effectively controlled by providing thermal conductivity characteristics. The CNT–CTO hybrid absorbed the NIR laser, converted it into heat, and transmitted it to the adjacent pNIPAM network. When pNIPAM received heat, a hydrophilic–hydrophobic phase transition occurred, and a white pattern was observed owing to a change in the refractive index inside the hydrogel. Upon stopping the application of the NIR laser, rapid cooling occurred due to the high thermal conductivity of the CNTs, and the hydrophobic–hydrophilic phase transition was quickly achieved and restored. Therefore, based on the results of this study, optical writing displays using heat-responsive polymers containing photothermal particles and NIR lasers are expected to be applicable for information transmission in extreme environments, such as aviation, space, and the military, owing to the ability of lasers to travel in a straight line.
A numerical study of natural convection through a vertical heated channel with a confined circular cylinder
Authors: Nguyen Quang Duy , Ji Siyu , Lei Chengwang
Published: March 2024

This study examines thermal flow structures and heat transfer through a vertical heated channel with an adiabatic circular cylinder symmetrically positioned between lateral walls. A two-dimensional numerical simulation is conducted covering a range of parameters including Rayleigh numbers Ra = 8.9 × 106–8.9 × 108, cylinder positions relative to the channel height h = 0–0.50, and blockage ratios (the ratio of cylinder diameter to channel width) β = 0.25–0.75. Three distinct flow regimes are observed at different Rayleigh numbers and blockage ratios, including steady symmetric, unsteady periodic, and unsteady asymmetric flow regimes. The steady symmetric and unsteady periodic flows are observed at all blockage ratios, while the unsteady asymmetric flow is only observed at the highest blockage ratio of β = 0.75 for Rayleigh numbers above 8.9 × 107. It is found that the presence of the cylinder significantly enhances mixing and turbulence in the channel, which in turn enhances heat transfer through the channel. A 64.3% enhancement of heat transfer is achieved at β = 0.50 and h = 0.05 for Ra = 8.9 × 108.
Heating from above in non-scattering suspension: Phototactic bioconvection under collimated irradiation
Authors: Kumar Sandeep , Wang Shaowei
Published: March 2024

Examining phototactic bioconvection in non-scattering suspensions with upper heating and collimated irradiation, this study delves into the intricate dynamics influenced by light and microorganisms. The study focuses on the linear stability of the basic state, examining neutral curves. The numerical analysis involves solving a system of equations using the MATLAB bvp4c solver. The investigation considers the impact of parameters, such as the thermal Rayleigh number, critical total intensity, and Lewis number, on the critical bioconvection Rayleigh number. As the critical total intensity varies, a transition from a stationary to an oscillatory solution (and vice versa) is observed. Phototactic microorganisms are incorporated into the model, and the results show how varying parameters affect convection patterns and stability. The findings reveal interesting phenomena, including Hopf bifurcations and limit cycles.
RAB3 phosphorylation by pathogenic LRRK2 impairs trafficking of synaptic vesicle precursors
Authors: Dou Dan , Aiken Jayne , Holzbaur Erika L.F.
Published: March 2024

Gain-of-function mutations in the LRRK2 gene cause Parkinson’s disease (PD), characterized by debilitating motor and non-motor symptoms. Increased phosphorylation of a subset of RAB GTPases by LRRK2 is implicated in PD pathogenesis. We find that increased phosphorylation of RAB3A, a cardinal synaptic vesicle precursor (SVP) protein, disrupts anterograde axonal transport of SVPs in iPSC-derived human neurons (iNeurons) expressing hyperactive LRRK2-p.R1441H. Knockout of the opposing protein phosphatase 1H (PPM1H) in iNeurons phenocopies this effect. In these models, the compartmental distribution of synaptic proteins is altered; synaptophysin and synaptobrevin-2 become sequestered in the neuronal soma with decreased delivery to presynaptic sites along the axon. We find that RAB3A phosphorylation disrupts binding to the motor adaptor MADD, potentially preventing the formation of the RAB3A–MADD-KIF1A/1Bβ complex driving anterograde SVP transport. RAB3A hyperphosphorylation also disrupts interactions with RAB3GAP and RAB-GDI1. Our results reveal a mechanism by which pathogenic hyperactive LRRK2 may contribute to the altered synaptic homeostasis associated with characteristic non-motor and cognitive manifestations of PD.
Positioning centrioles and centrosomes
Authors: Hannaford Matthew R. , Rusan Nasser M.
Published: March 2024

Centrosomes are the primary microtubule organizer in eukaryotic cells. In addition to shaping the intracellular microtubule network and the mitotic spindle, centrosomes are responsible for positioning cilia and flagella. To fulfill these diverse functions, centrosomes must be properly located within cells, which requires that they undergo intracellular transport. Importantly, centrosome mispositioning has been linked to ciliopathies, cancer, and infertility. The mechanisms by which centrosomes migrate are diverse and context dependent. In many cells, centrosomes move via indirect motor transport, whereby centrosomal microtubules engage anchored motor proteins that exert forces on those microtubules, resulting in centrosome movement. However, in some cases, centrosomes move via direct motor transport, whereby the centrosome or centriole functions as cargo that directly binds molecular motors which then walk on stationary microtubules. In this review, we summarize the mechanisms of centrosome motility and the consequences of centrosome mispositioning and identify key questions that remain to be addressed.
Adaptive mesh refinement in binary black holes simulations
Authors: Rashti Alireza , Bhattacharyya Maitraya , Radice David , Daszuta Boris , Cook William , Bernuzzi Sebastiano
Published: March 2024

We discuss refinement criteria for the Berger–Rigoutsos (block-based) refinement algorithm in our numerical relativity code GR-Athena++ in the context of binary black hole (BBH) merger simulations. We compare three different strategies: the ‘box-in-box’ approach, the ‘sphere-in-sphere’ approach and a local criterion for refinement based on the estimation of truncation error of the finite difference scheme. We extract and compare gravitational waveforms using the three different mesh refinement methods and compare their accuracy against a calibration waveform and demonstrate that the sphere-in-sphere approach provides the best strategy overall when considering computational cost and the waveform accuracy. Ultimately, we demonstrate the capability of each mesh refinement method in accurately simulating gravitational waves from BBH systems—a crucial aspect for their application in next-generation detectors. We quantify the mismatch achievable with the different strategies by extrapolating the gravitational wave mismatch to higher resolution.
Fabrication of micro-ultrasonic phased array electrode via electric field-driven printing method
Authors: Cheng E , Zhu Yeming , Deng Qibo , Zhang Zhengyan , Tian Xintao
Published: March 2024

The electrode is an important part of a micro-ultrasonic phased array, commonly fabricated by magnetron sputtering technology. However, with the expansion of the application field, the structures of the phased arrays are becoming more complex, making the traditional magnetron sputtering method no longer applicable, and the realization of micro-scale phased array electrodes by direct printing technology still faces great challenges. Herein, an electric field-driven direct printing method was proposed to fabricate micro-ultrasonic phased array electrodes. The influence of sintering parameters on the resistivity and the effect of printing parameters on the geometric size and surface morphology of the electrode were comprehensively explored, and the mathematical model between the electrode line width and the printing parameters was established. The final printed electrodes exhibit superior properties with a resistivity of 2.4 × 10−7

Ω
⋅
m

, a surface roughness range of 460–550 nm, and a line width range of 125–480 µm. Additionally, a micro-scale electrode was printed on the piezoelectric ceramic with PZT-5 as the material, and after polarization treatment, the piezoelectric coefficient can reach 405 pC N−1, which proves that this method can be applied in the field of fabricating phased array electrodes.
Numerical and experimental investigation on droplet entrainment mechanism and closed equations of two-fluid model
Authors: Wang Mi , Liu Jiegui , Bai Yuxin , Fang Lide
Published: March 2024

As a clean and low-carbon energy source, natural gas is an important force in achieving carbon peaking and carbon neutrality goals. Affected by the strong force of gas and liquid during mining and transportation, it exhibits the phenomenon of droplet entrainment. Entrained droplets change the properties of gas and liquid phases, which is crucial for accurate measurement of liquid film thickness, gas holdup, pressure drop and flow rates in natural gas pipelines. The measurement of entrained droplets has always been a focus and difficulty in the two-phase flow research field. Therefore, numerical simulation combined with experimental measurement are presented to study the droplet entrainment mechanism and closed equations of two-fluid model. The specific parameter settings for simulating horizontal gas–liquid annular flow based on numerical method are discussed, and effective simulation of droplet entrainment and deposition in annular flow is achieved. By comparing liquid film thickness and wave velocity from the simulation results with the experimental results, the correctness of the simulation method is verified. Then, the mechanism and dynamic evolution process of entrained droplets in annular flow are revealed, and the generation and deposition characteristics of entrained droplets are studied. As a result, the closed equations of two-fluid model such as droplet velocity, gas–liquid interface velocity, and gas–liquid interface friction factor are established. The proposed two-fluid model is validated using dual mode ultrasound and differential pressure sensors, demonstrating its good applicability and extrapolation.
Green synthesized Cu-doped CeO2 nanoparticles for Congo red dye adsorption and antibacterial action
Authors: Norbert Aleena , A Surya Mary , John Sareen Sarah , Shaji Sadasivan , Jacob Mohan V , Philip Rachel Reena
Published: March 2024

The removal of pollutants from water bodies is crucial for the well-being of humanity and is a topic of global research. Researchers have turned their attention to green synthesized nanoparticles for wastewater treatment due to their eco-friendly nature, biocompatibility, and cost-effectiveness. This work demonstrates the efficient removal of organic dye and both gram-positive and gram-negative bacteria from water bodies using copper-doped cerium oxide nanoparticles synthesized with Murraya Koenigii extract. Characterized via various methods, the 15% copper doped cerium oxide nanoparticles (Cu 15% NPs) exhibited maximum Congo red dye adsorption (98% degradation in 35 min). Kinetic analysis favoured a pseudo-second-order model, indicating the chemical nature of adsorption. Equilibrium adsorption isotherms aligned with the Langmuir model, indicating homogenous monolayer dye adsorption on the doped adsorbent. The maximum uptake of adsorbate, Q
m obtained from Langmuir model for Cu 15% NPs was 193 mg g−1. The study also showed enhanced antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa for Cu-doped ceria, attributed to generation of reactive oxygen species (ROS) induced by the redox cycling between Ce3+ and Ce4+. This substantiated that the green synthesized copper doped cerium oxide nanoparticles are potential candidates for adsorptive removal of Congo red dye and as antibacterial agents.
The plasma-charge model in a convex domain
Authors: Wu Jingpeng
Published: March 2024

The aim of this paper is to study the initial-boundary value problems of a Vlasov type system in a convex domain, so called the plasma-charge model, in which there are two kinds of singular sets, one caused by the boundary effect, the other by the heavy point charges. We prove the local existence of classical solutions for the case that the point charges are moving and global existence of classical solutions for the case that the point charges are fixed away from the boundary. The crucial tools are the extended Velocity Lemma for the plasma-charge model and the Pfaffelmoser’s method developed by Hwang and Velázquez (2010 Arch. Ration. Mech. Anal.
195 763–96) and Marchioro et al (2011 Arch. Ration. Mech. Anal.
201 1–26). In the Pfaffelmoser’s argument, a new idea is that the plasma particles can only be close to one of the singular sets during the time interval

[
t
−
δ
,
t
]

with small length δ, which allows us to obtain the global existence for the fixed point charges case by adapting the techniques established by Hwang et al (2013 Discrete Contin. Dyn. Syst.
33 723–37; 2010 Arch. Ration. Mech. Anal.
195 763–96) and Marchioro et al (2011 Arch. Ration. Mech. Anal.
201 1–26) to the corresponding singular sets respectively.