bluuebunny/crossref_metadata_2025 huggingface dataset:
Métodos de avaliação do regenerado ósseo
Authors: Cardoso Gracielle Silva , Amorim Renato
Published: March 2024

Desde que foi descrita por Ilizarov, a técnica de osteogênese por distração tem sido utilizada para o tratamento de diversas condições relacionadas ao trauma, infecções, tumores ósseos e doenças congênitas, na forma de transporte ou alongamento ósseo. Um dos dilemas mais comuns do cirurgião ortopédico que realiza distração osteogênica é o estabelecimento de um método reprodutível de verificação da progressão da osteogênese, que permita a detecção precoce de falhas no regenerado, para que se possa interferir de forma eficaz durante o tratamento, bem como determinar o tempo apropriado de remoção do fixador externo. Recentemente, vários métodos de monitoramento quantitativo, com os quais se poderia avaliar a recuperação da estrutura e as propriedades biomecânicas do regenerado ósseo em diferentes estágios, além do processo de cicatrização óssea, têm sido amplamente investigados. Por esses métodos, pode-se saber o conteúdo mineral ósseo, a densidade mineral óssea, a rigidez e o metabolismo ósseo. Nesta revisão, resumimos de forma abrangente as técnicas mais recentes para avaliar a cicatrização óssea durante a distração osteogênica, entre elas, métodos como a radiografia convencional e os valores de pixels em radiologia digital, a ultrassonografia, a densitometria e a cintilografia ósseas, a tomografia computadorizada quantitativa, a avaliação biomecânica, os marcadores bioquímicos e os modelos matemáticos. Consideramos fundamental o conhecimento dos diversos métodos à disposição atualmente e entendemos que a utilização de vários métodos de monitoramento simultaneamente possa ser uma solução ideal, que aponte para uma direção futura no seguimento da distração osteogênica.
Uso de redes sociais por cirurgiões com treinamento especializado em trauma ortopédico
Authors: Smith Haley E. , Cantrell Colin K. , Goedderz Cody J. , Wiese Michelle L. , Memon Ramiz , Williams Joel C.
Published: March 2024

Objetivo: Quantificar o uso de plataformas de rede social por traumato-ortopedistas, com ênfase nas diferenças demográficas, regionais e de tipo de prática clínica.

Materiais e Métodos: Utilizando o banco de dados de membros da Orthopaedic Trauma Association (OTA), foram realizadas pesquisas on-line para identificar perfis de profissionais em diversas plataformas de rede social. Esta presença foi quantificada por uma pontuação cumulativa de redes sociais, que foi correlacionada com as informações demográficas coletadas.

Resultados: Foram identificados 1.262 profissionais com treinamento especializado em trauma ortopédico. Observou-se que os cirurgiões que atuam em ambiente acadêmico têm maior probabilidade de usar diversas plataformas de rede social e apresentam pontuação geral maior em redes sociais do que aqueles que atuam em consultório particular. Não foram encontradas diferenças significativas quanto ao uso de redes sociais com base na região de atuação.

Conclusão: Atualmente, as plataformas de rede social são subutilizadas pelos traumato-ortopedistas.

Nível de Evidência: IV.
Técnica do túnel femoral transtibial na reconstrução do LCA e incidência de osteoartrite
Authors: Danieli Marcus Vinicius , Molinari Allan Viktor Pires , Suzze João Vitor Guedes , Abreu Victoria de , Guerreiro João Paulo Fernandes
Published: March 2024

Objetivo: Avaliar a incidência de osteoartrite em pacientes submetidos à reconstrução do LCA pela técnica transtibial, com seguimento mínimo de 5 anos, com lesão isolada do LCA.

Métodos: Pacientes que passaram por reconstrução LCA pelo mesmo cirurgião usando a técnica transtibial com enxerto de tendão dos músculos isquiotibiais e que foram acompanhados por no mínimo 5 anos, sem outras lesões durante o procedimento cirúrgico, foram selecionados para realizar exames de imagem do joelho operado a fim de avaliar a incidência de osteoartrite. Os dados obtidos foram avaliados por meio de estatísticas descritivas..

Resultados: Foram avaliados 42 pacientes (44 joelhos), com idade média de 31 anos (DP: 8), sendo 23 joelhos direitos e 28 pacientes do sexo masculino. O tempo médio entre a cirurgia e a avaliação por imagem foi de 94,1 meses (variando de 60 a 154 meses; DP: 28). Dos joelhos avaliados, 37 não apresentavam osteoartrite (83,3%) e 7 apresentavam (16,7%).

Conclusão: A reconstrução do LCA com túnel femoral realizado por meio da técnica transtibial em pacientes sem outras lesões associadas no joelho operado, utilizando enxerto dos tendões isquiotibiais, com um acompanhamento mínimo de 5 anos, apresentou uma incidência de osteoartrite de 16,7% em um acompanhamento médio de 94,1 meses.

Level of Evidence V; Case Series.

Nível de Evidência V; Série de casos
Técnica de sutura minimamente invasiva pull-out para reparar lesões agudas dos tendões flexores da zona II da mão
Authors: Belloti João Carlos , Buendia Luis Antonio , Tamaoki Marcel Jun , Santos João Batista Gomes dos , Falopa Flávio , Ulson Heitor José Rizardo
Published: March 2024

Objetivo: Avaliar a segurança e a efetividade da técnica de sutura pull-out modificada nos pacientes submetidos à cirurgia de reparo primário das lesões dos tendões flexores nos dedos, tendo como desfecho primário o movimento ativo total (TAM).

Método: Foram escolhidos 29 pacientes (38 dedos), de ambos os sexos, com idade entre 18 e 65 anos, com laceração tendinosa aguda e limpa, ocorrida em até 15 dias, na zona II de Verdan do tendão flexor da mão, quando apenas o tendão flexor profundo foi suturado, associada ou não à lesão do nervo digital. Os pacientes foram operados pela técnica proposta e avaliados em 3, 9 e 24 semanas PO. O desfecho primário foi a avaliação do movimento ativo total (TAM) e foram empregadas 3 classificações: Strickland, IFSSH e Buck-Gramcko.

Resultados: Observamos um movimento ativo total (TAM) de 209,3° ao final de 24 semanas; 83,0% de resultados Bons e Excelentes pela Classificação de Strickland Modificada, 93% de resultados Excelentes pela Classificação IFSSH e 97% de resultados Bons e Excelentes pela Classificação Buck-Gramcko. Não houve casos de ruptura, mas foi observada aderência tendínea em 3 dedos.

Conclusão: A presente técnica de sutura mostrou-se segura e eficaz com baixo índice de complicações, obtendo excelente resultado funcional em termos de mobilidade ativa total, de acordo com as avaliações e classificações utilizadas.
Os ângulos de distalização e lateralização do ombro na artroplastia reversa podem interferir nos resultados funcionais em pacientes com artropatia do manguito rotador?
Authors: Dainotto Tamara , Gómez Diego , Ernst Glenda
Published: March 2024

Objetivo: Avaliar a influência dos valores radiográficos nos resultados clínicos e funcionais em pacientes tratados com artroplastia reversa para artropatia do manguito rotador utilizando um desenho lateralizado.

Métodos: Foi realizada uma análise retrospectiva. Foram registradas as demografias dos pacientes, bem como o intervalo de movimento pré-operatório e pós-operatório. A função foi calculada usando a pontuação Constant-Murley tanto antes como depois do procedimento. Radiografias pré e pós-operatórias anteroposteriores e axiais do ombro afetado foram analisadas. Nas imagens pré-operatórias, foram calculados a distância acromioumeral (DAU) e offset lateral umeral (OLU). As medidas pós-operatórias incluídas foram DAU, OLU, ângulo de distalização do ombro (ADO) e ângulo de lateralização do ombro (ALO). Foi realizada uma análise de regressão linear e regressão quadrática para determinar seu grau de associação com os resultados funcionais finais. Aplicando uma análise de regressão quadrática e curvas ROC, os valores de corte foram determinados em relação aos ângulos acima mencionados e o valor preditivo positivo foi calculado.

Resultados: As maiores faixas de elevação anterior (EA) foram encontradas com ADO entre 40 e 45° e ALO entre 80 e 90°, enquanto a melhor abdução (ABD) foi observada com ALO de 90 e 100°. A DAU pré-operatória foi correlacionada com a rotação externa (RE) (rs: 0,47; p: 0,049). A DAU pós-operatória apresentou uma relação diretamente proporcional com a EA (rs: 0,49; p: 0,03). A ABD pós-operatória mostrou uma regressão linear inversa com a DAU pré-operatória (rs: -0,44, p: 0,047). O ALO e o ADO estavam inversamente relacionados.

Conclusão: Determinamos que um ADO entre 40 e 45° e um ALO de 80 e 100° poderia levar a uma melhor amplitude de movimento em relação à EA e ABD em pacientes com artropatia do manguito rotador tratados com artroplastia reversa de ombro.
Avaliação do tratamento cirúrgico de pacientes acima de 90 anos com fraturas de quadril e sua morbimortalidade
Authors: Burguêz Daniela , Menegatti Rangel , Susin Felipe Odeh , Dornelles Lauro Manoel Etchepare , Serafini Osvaldo André
Published: March 2024

Objetivo: As fraturas de quadril em idosos são as que mais impactam na saúde do paciente e estão associadas a muitas complicações, levando a redução da capacidade funcional, da qualidade de vida e da expectativa de vida. O nosso trabalho visa trazer mais dados epidemiológicos sobre os desfechos dessas fraturas em nonagenários em uma grande cidade atendidos em um hospital terciário.

Métodos: O trabalho foi realizado através de revisão de prontuários e entrevistas.

Resultados: Foram realizadas 82 cirurgias em 76 pacientes nesse período. A média de idade foi de 92,5 anos, 90% eram mulheres e ficaram 10,4 dias internados. A cirurgia foi realizada em média 2,3 dias após a internação. Do total, 46 fraturas foram trocantéricas (56%) e 34 do colo do fêmur (41,5%). Foram realizadas 41 cirurgias com a técnica da haste cefalomedular curta (50%) e 18 artroplastias parcial de quadril (22%). Durante a internação, 46 pacientes (55%) não apresentaram complicações, excluindo episódios de delirium, e 7 pacientes (9% dos casos) evoluíram para óbito. 42 pacientes já fecharam 1 ano após cirurgia: 56% estão vivos e 44% evoluíram para óbito.

Conclusões: O tratamento de fraturas de quadril em pacientes idosos é desafiador. O nosso objetivo deve estar focado em ajudar esses idosos a receber um tratamento rápido e menos agressivo possível e a mobilizar precocemente. Esperamos que, com os dados apresentados nesse trabalho, possamos entender melhor acerca das características da nossa população nonagenária vítimas de fratura de quadril e buscar o melhor tratamento possível para esses pacientes.
Parafuso pedicular percutâneo em fraturas toracolombares: Acompanhamento em longo prazo
Authors: Furtado Marcos Vinícius da Rocha , Braga Gabriel Santos , Rossanez Roberto , Herrero Carlos Fernando Pereira da Silva
Published: March 2024

Objetivo: Este é um estudo de coorte retrospectivo para analisar os desfechos em longo prazo de pacientes com fratura da coluna toracolombar submetidos à fixação percutânea minimamente invasiva.

Métodos: Os casos de 17 pacientes com fraturas da coluna toracolombar submetidos à fixação percutânea entre 2009 e 2011 foram objeto de análise retrospectiva. Variáveis clínicas e radiográficas foram coletadas. A avaliação clínica foi baseada nos questionários SF-36 e Oswestry. Os parâmetros radiográficos foram avaliados de acordo com a classificação de fratura baseada nos critérios de Magerls, o ângulo de cunha da vértebra fraturada e o ângulo de Cobb do segmento acometido. As medidas foram feitas em diferentes momentos: antes da cirurgia, imediatamente após a cirurgia, um ano depois e no acompanhamento tardio (cinco anos depois). Lesões associadas a traumas, complicações pós-cirúrgicas e relacionadas a implantes também foram consideradas.

Resultados: O questionário SF-36 apresentou médias acima de 63,5% em todos os domínios no período pós-operatório tardio (a partir de cinco anos após a cirurgia). As respostas do questionário Oswestry mostraram limitações físicas mínimas ou nulas em 80% dos pacientes, com pontuação média de 10,8% ± 10,5%. O valor médio do ângulo de Cobb foi de 5,53° ± 13,80° de cifose no período pré-operatório, 2,18° ± 13,38° de cifose no pós-operatório imediato, 5,26 ± 13,95° de cifose no pós-operatório de um ano e de 8,78° ± 15,06° de cifose no período pós-operatório tardio. A correção média foi de 3,35° e a perda média de correção foi de 6,6°. Não foram observadas complicações, casos de déficit neurológico, infecções ou falhas do implante.

Conclusão: As fraturas das vértebras toracolombares podem ser tratadas cirurgicamente com desfechos clínicos e radiológicos tardios positivos e baixas taxas de complicações usando um método percutâneo minimamente invasivo.
Shared recycling model for waste electrical and electronic equipment based on the targeted responsibility system in the context of China
Authors: Chu Tao , Ma Jingai , Zhong Yongguang , Sun Hao , Jia Weiqiang
Published: March 2024

The formal recycling of waste electrical and electronic equipment (WEEE) has long faced collection difficulties owing to the inadequate recycling system and insufficient collection capacity under China’s fund-based recycling model. The government has introduced the recycling Target Responsibility System (TRS) to motivate producers to develop and share recycling systems, yet without clear incentive mechanisms. In this study, we provide a “1 + N” shared recycling model referring to the theory of the sharing economy, and we propose a credit mechanism with a deposit system and a penalty mechanism for dishonesty to constrain the opportunistic behavior of sharing. In addition, according to the TRS, we design a “reduction-penalty-subsidy” fund policy to incentivize producers and recyclers to achieve recycling targets. On this basis, we apply evolutionary game theory and system dynamics approach to analyze the collaborative mechanism of shared recycling and the incentive effect of the funding policy. Game analysis yields the evolution of shared recycling from the developing stage to the mature stage. The system simulation results indicate that the government’s “penalty” and “subsidy” strategies provide evident incentives for producers and recyclers, respectively, in the developing stage, whereas endogenous dynamics derived from economies of scale under market mechanisms promote the multi-agent collaborative implementation of shared recycling in the mature stage.
An investigation into employees’ factors of flexible working hours (FWH) for productivity in Saudi: a mixed qualitative triangulation
Authors: Mohiya Mohamed
Published: March 2024

One of the most controversial HRM topics that have received extensive attention from academics and practitioners communities over the past two decades is flexible working hours (FWH) and its impact on productivity. Nevertheless, the work is focused almost exclusively on business and organizational aspects neglecting the employees’ and social perspectives, and thus far lacks a strong theoretical foundation, particularly social theory. Therefore, unlike other work, the present study focuses heavily on the employees’ perspective based on a social theory; namely: social exchange theory (SET). This study aims to explore and evaluate the antecedents for requesting FWH, mainly: employee and social-related factors, which affect their productivity. SET was found valuable to serve the aim of the research because it magnifies the importance of the employee as a partner who is in reciprocal social relations. Two mixed triangulated sets of qualitative data were collected, namely: semi-structured interviews and document analysis (cross-sectional and longitudinal). Thirty-two interviews were conducted with employees and with management. Document analysis is a novel source of data that was extracted from the company’s internal technological platform and contains employees’ first-hand computerized typewritten comments about FWH. The analysis of the findings reveals that the most significant factors found affecting employees’ decision to demand FWH for productivity are midday breaks, traffic/transportation, schooling, and social life. Moreover, the findings suggest that HR practitioners need to recognize employees’ social factors before applying FWH practice. This present research makes an original and important contribution to HRM scholarship and reflects theoretical rigor (social exchange theory), methodological (mixed triangulation methods), empirical, and practical. For example, theoretical contributions regarding SET’s reciprocity “black box” were highlighted. Moreover, the implication of the findings assists HR, in particular in Saudi organizations, to ensure the FWH contributes to overcoming these identified employees’ related antecedents.
Quantifying recombination and charge carrier extraction in halide perovskites via hyperspectral time-resolved photoluminescence imaging
Authors: Phirke H. , Gharabeiki S. , Singh A. , Krishna A. , Siebentritt S. , Redinger A.
Published: March 2024

Identifying sources of nonradiative recombination and quantifying charge carrier extraction in halide perovskite solar cells are important in further developing this thin-film technology. Steady-state and time-resolved photoluminescence (TRPL), in combination with analytical modeling, have emerged as non-destructive tools to achieve the desired results. However, the exact location of the recombination and charge carrier extraction losses in devices is often obscured by various competing processes when photoluminescence measurements are analyzed. Here, we show via absolute-photon-calibrated hyperspectral photoluminescence and TRPL imaging how surface passivation and inhomogeneities at interfaces impact the photoluminescence quantum yields and minority carrier lifetimes. Laser illumination from the perovskite and glass/TiO2 sides allows us to disentangle changes in surface recombination velocity from the charge carrier extraction at the electron transport layer. We find that charge extraction is spatially modulated due to an inhomogeneous mesoporous (mp)-TiO2 film thickness. Our results show that the mp-TiO2 layer is not fully optimized since the electronic properties are spatially modified, leading to lateral changes in quasi-Fermi-level splitting, minority carrier lifetime and, consequently, a reduction in open-circuit voltage.
StyleGAN as an AI deconvolution operator for large eddy simulations of turbulent plasma equations in BOUT++
Authors: Castagna J. , Schiavello F. , Zanisi L. , Williams J.
Published: March 2024

We present the use of StyleGAN, a face-synthesis generative adversarial network (GAN) developed by NVidia, as a deconvolution operator for large eddy simulation (LES) of plasma turbulence. The overall methodology, named style eddy simulation, has been integrated into the BOUT++ solver and tested on the original and modified Hasegawa–Wakatani models using different mesh sizes, 2562 and 5122, and different values of the adiabaticity parameter α and background density gradient κ. Using a LES resolution of 32 × 32 and 64 × 64, i.e., 64× smaller resolution than the corresponding direct numerical simulation (DNS), results show convergence toward the ground truth as we tighten the reconstruction tolerance, and an algorithm complexity O(N log N) is compared to the O(N2) of BOUT++. Finally, the trained GAN can be used to create valid initial conditions for a faster DNS by avoiding to start from nonphysical initial perturbations.
On parallel laser beam merger in plasmas
Authors: Lezhnin K. V. , Qu Kenan , Fisch N. J. , Bulanov S. V.
Published: March 2024

Self-focusing instability is a well-known phenomenon of nonlinear optics, which is of great importance in the field of laser–plasma interactions. Self-focusing instability leads to beam focusing and, consequently, breakup into multiple laser filaments. The majority of applications tend to avoid a laser filamentation regime due to its detrimental role on laser spot profile and peak intensity. In our work, using nonlinear Schrödinger equation solver and particle-in-cell simulations, we address the problem of interaction of multiple parallel beams in plasmas. We consider both non-relativistic and moderately relativistic regimes and demonstrate how the physics of parallel beam interaction transitions from the familiar self- and mutual-focusing instabilities in the non-relativistic regime to a moderately relativistic regime, where an analytical description of filament interaction is not available.
Single-molecule analysis of solvent-responsive mechanically interlocked ring polymers and the effects of nanoconfinement from coarse-grained simulations
Authors: Becerra Diego , Klotz Alexander R. , Hall Lisa M.
Published: March 2024

In this study, we simulate mechanically interlocked semiflexible ring polymers inspired by the minicircles of kinetoplast DNA (kDNA) networks. Using coarse-grained molecular dynamics simulations, we investigate the impact of molecular topological linkage and nanoconfinement on the conformational properties of two- and three-ring polymer systems in varying solvent qualities. Under good-quality solvents, for two-ring systems, a higher number of crossing points lead to a more internally constrained structure, reducing their mean radius of gyration. In contrast, three-ring systems, which all had the same crossing number, exhibited more similar sizes. In unfavorable solvents, structures collapse, forming compact configurations with increased contacts. The morphological diversity of structures primarily arises from topological linkage rather than the number of rings. In three-ring systems with different topological conformations, structural uniformity varies based on link types. Extreme confinement induces isotropic and extended conformations for catenated polymers, aligning with experimental results for kDNA networks and influencing the crossing number and overall shape. Finally, the flat-to-collapse transition in extreme confinement occurs earlier (at relatively better solvent conditions) compared to non-confined systems. This study offers valuable insights into the conformational behavior of mechanically interlocked ring polymers, highlighting challenges in extrapolating single-molecule analyses to larger networks such as kDNA.
Discovering invariant spatial features in electron energy loss spectroscopy images on the mesoscopic and atomic levels
Authors: Roccapriore Kevin M. , Ziatdinov Maxim , Lupini Andrew R. , Singh Abhay P. , Philipose Usha , Kalinin Sergei V.
Published: March 2024

Over the last two decades, Electron Energy Loss Spectroscopy (EELS) imaging with a scanning transmission electron microscope has emerged as a technique of choice for visualizing complex chemical, electronic, plasmonic, and phononic phenomena in complex materials and structures. The availability of the EELS data necessitates the development of methods to analyze multidimensional data sets with complex spatial and energy structures. Traditionally, the analysis of these data sets has been based on analysis of individual spectra, one at a time, whereas the spatial structure and correlations between individual spatial pixels containing the relevant information of the physics of underpinning processes have generally been ignored and analyzed only via the visualization as 2D maps. Here, we develop a machine learning-based approach and workflows for the analysis of spatial structures in 3D EELS data sets using a combination of dimensionality reduction and multichannel rotationally invariant variational autoencoders. This approach is illustrated for the analysis of both the plasmonic phenomena in a system of nanowires and in the core excitations in functional oxides using low loss and core-loss EELS, respectively. The code developed in this manuscript is open sourced and freely available and provided as a Jupyter notebook for the interested reader.
A closer examination of the nature of atomic motion in the interfacial region of crystals upon approaching melting
Authors: Zhang Jiarui , Zhang Hao , Douglas Jack F.
Published: March 2024

Although crystalline materials are often conceptualized as involving a static lattice configuration of particles, it has recently become appreciated that string-like collective particle exchange motion is a ubiquitous and physically important phenomenon in both the melting and interfacial dynamics of crystals. This type of collective motion has been evidenced in melting since early simulations of hard disc melting by Alder et al. [Phys. Rev. Lett. 11(6), 241–243 (1963)], but a general understanding of its origin, along with its impact on melting and the dynamics of crystalline materials, has been rather slow to develop. We explore this phenomenon further by focusing on the interfacial dynamics of a model crystalline Cu material using molecular dynamics simulations where we emphasize the geometrical nature and spatial extent of the atomic trajectories over the timescale that they are caged, and we also quantify string-like collective motion on the timescale of the fast β-relaxation time, τf, i.e., “stringlets.” Direct visualization of the atomic trajectories in their cages over the timescale over which the cage persists indicates that they become progressively more anisotropic upon approaching the melting temperature Tm. The stringlets, dominating the large amplitude atomic motion in the fast dynamics regime, are largely localized to the crystal interfacial region and correspond to “excess” modes in the density of states that give rise to a “boson peak.” Moreover, interstitial point defects occur in direct association with the stringlets, demonstrating a link between classical defect models of melting and more recent studies of melting emphasizing the role of this kind of collective motion.
Iron-nitrogen co-doped biochar (FeN@BC) as particle electrode for three-dimensional (3D) electro-peroxydisulfate process for tetracycline degradation
Authors: He Dongcai , Chen Pu , Zheng Peng , Yang Mengying , Liu Lang , Yuan Shaochun
Published: March 2024

In this work, a three-dimensional electrode material (FeN@BC) was prepared by doping iron-nitrogen sites into biochar for activating peroxydisulfate (E-FeN@BC-PS). The scanning electron microscope, x-ray diffractometer, Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy results of FeN@BC proved that Fe–N sites were successful doped into BC. Electrochemical analysis indicated that FeN@BC could enhance the electron transfer in the electrochemical process. A significant synergistic effect (SI = 12.46) was observed in the E-FeN@BC-PS system. Tetracycline (TC) was almost removed completely within 30 min in optimal operating parameters. Radical scavenging experiments showed that ·OH, SO4●−, O2●−, and 1O2 all contributed to TC degradation. The cyclic experiment and characterizations before and after the recycle showed that the FeN@BC in the three-dimensional electrode system exhibited excellent stability and reusability, and electricity had an obvious protective effect on the FeN@BC materials. This study revealed the synergistic catalytic mechanism of metal and heteroatomic hybrid materials as three-dimensional electrodes in persulfate activation, promising the development of sustainable and efficient water treatment technology.
Hybrid mesoporous electrodes evidence CISS effect on water oxidation
Authors: Vensaus Priscila , Liang Yunchang , Zigon Nicolas , Avarvari Narcis , Mujica Vladimiro , Soler-Illia Galo J. A. A. , Lingenfelder Magalí
Published: March 2024

Controlling product selectivity is essential for improving the efficiency of multi-product reactions. Electrochemical water oxidation is a reaction of main importance in different applications, e.g., renewable energy schemes and environmental protection, where H2O2 and O2 are the two principal products. In this Communication, the product selectivity of electrochemical water oxidation was controlled by making use of the chiral induced spin selectivity (CISS) effect at mesoporous-TiO2 on the molecule-modified Au substrate. Our results show a decrease in H2O2 formation when using chiral hetero-helicene molecules adsorbed on the Au substrate. We propose a mechanism for this kinetic effect based on the onset of CISS-induced spin polarization on the Au–helicene chiral interface. We also present a new tunable substrate to investigate the CISS mechanism.
Study on the method of evaluating the failure of stator bar insulation materials based on mechanical damage characteristics
Authors: Feng Ju , Hu Bo , Ma Sude
Published: March 2024

The damage impact of mechanical shocks on stator bar insulation is a key factor in high-voltage motor accidents. This study conducted electrical aging acceleration and breakdown experiments on damaged stator insulating materials to understand failure causes and evaluation methods. The relationship between sample defect area and depth and electrical properties was analyzed, along with the morphology of the damaged surface using a scanning electron microscope. Results show that the defect area correlates with impact mode but does not directly impact electrical performance. Effective insulation thickness is positively linked to electrical performance. This study serves as a valuable reference for evaluating mechanical impact faults in high-voltage motors.
Do sulphur-crested cockatoos (Cacatua galerita) call the weather?
Authors: Gillies Marissa L. , Brown Culum
Published: March 2024

Storms can have significant impacts on wildlife and many animals, including birds, can predict a storm’s arrival and change their behaviour accordingly. Storms are often associated with changes in environmental variables, particularly with a fall in barometric pressure. Social animals may collectively detect and advertise the potential onset of inclement weather to facilitate group responses. The present study tested the hypothesis that the sulphur-crested cockatoo uses environmental cues to predict the onset of storms and communicates this to conspecifics by emitting a specific ‘rain call’. Field observations were made over a four-month period at four locations in greater Sydney. Cockatoo calls were recorded, along with multiple environmental variables: barometric pressure, relative humidity, rainfall and temperature. We also noted the time of day relative to sunrise and sunset. We found that rain calls occurred throughout the day but were most prominent at dawn and were far more common at two of the four study sites. Rain calls were more likely to occur at slightly lower temperatures, during periods of high humidity and if it was currently raining. We found no evidence that the calls were prompted by current atmospheric pressure, but the observation period did not contain many storms.
Fluid fibers in true 3D ferroelectric liquids
Authors: Jarosik Alexander , Nádasi Hajnalka , Schwidder Michael , Manabe Atsutaka , Bremer Matthias , Klasen-Memmer Melanie , Eremin Alexey
Published: March 2024

We demonstrate an exceptional ability of a high-polarization 3D ferroelectric liquid to form freely suspended fluid fibers at room temperature. Unlike fluid threads in modulated smectics and columnar phases, where translational order is a prerequisite for forming liquid fibers, recently discovered ferroelectric nematic forms fibers with solely orientational molecular order. Additional stabilization mechanisms based on the polar nature of the mesophase are required for this. We propose a model for such a mechanism and show that these fibers demonstrate an exceptional nonlinear optical response and exhibit electric field-driven instabilities.
Mid-infrared trace detection with parts-per-quadrillion quantitation accuracy: Expanding frontiers of radiocarbon sensing
Authors: Jiang Jun , McCartt A. Daniel
Published: March 2024

Detection sensitivity is a critical characteristic to consider during selection of spectroscopic techniques. However, high sensitivity alone is insufficient for spectroscopic measurements in spectrally congested regions. Two-color cavity ringdown spectroscopy (2C-CRDS), based on intra-cavity pump–probe detection, simultaneously achieves high detection sensitivity and selectivity. This combination enables mid-infrared detection of radiocarbon dioxide (

14

CO

2

) molecules in room-temperature CO

2

samples, with 1.4 parts-per-quadrillion (ppq, 10

−
15

) sensitivity (average measurement precision) and 4.6-ppq quantitation accuracy (average calibrated measurement error for 21 samples from four separate trials) demonstrated on samples with

14

C/C up to

∼

1.5

×

natural abundance (

∼

1,800 ppq). These highly reproducible measurements, which are the most sensitive and quantitatively accurate in the mid-infrared, are accomplished despite the presence of orders-of-magnitude stronger, one-photon signals from other CO

2

isotopologues. This is a major achievement in laser spectroscopy. A room-temperature-operated, compact, and low-cost 2C-CRDS sensor for

14

CO

2

benefits a wide range of scientific fields that utilize

14

C for dating and isotope tracing, most notably atmospheric

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CO

2

monitoring to track CO

2

emissions from fossil fuels. The 2C-CRDS technique significantly enhances the general utility of high-resolution mid-infrared detection for analytical measurements and fundamental chemical dynamics studies.
Cross-pollination in seed-blended refuge and selection for Vip3A resistance in a lepidopteran pest as detected by genomic monitoring
Authors: Pezzini Daniela , Taylor Katherine L. , Reisig Dominic D. , Fritz Megan L.
Published: March 2024

The evolution of pest resistance to management tools reduces productivity and results in economic losses in agricultural systems. To slow its emergence and spread, monitoring and prevention practices are implemented in resistance management programs. Recent work suggests that genomic approaches can identify signs of emerging resistance to aid in resistance management. Here, we empirically examined the sensitivity of genomic monitoring for resistance management in transgenic Bt crops, a globally important agricultural innovation. Whole genome resequencing of wild North American
Helicoverpa zea
collected from non-expressing refuge and plants expressing Cry1Ab confirmed that resistance-associated signatures of selection were detectable after a single generation of exposure. Upon demonstrating its sensitivity, we applied genomic monitoring to wild
H. zea
that survived Vip3A exposure resulting from cross-pollination of refuge plants in seed-blended plots. Refuge seed interplanted with transgenic seed exposed
H. zea
to sublethal doses of Vip3A protein in corn ears and was associated with allele frequency divergence across the genome. Some of the greatest allele frequency divergence occurred in genomic regions adjacent to a previously described candidate gene for Vip3A resistance. Our work highlights the power of genomic monitoring to sensitively detect heritable changes associated with field exposure to Bt toxins and suggests that seed-blended refuge will likely hasten the evolution of resistance to Vip3A in lepidopteran pests.
Single-step precision programming of decoupled multiresponsive soft millirobots
Authors: Zheng Zhiqiang , Han Jie , Shi Qing , Demir Sinan Ozgun , Jiang Weitao , Sitti Metin
Published: March 2024

Stimuli-responsive soft robots offer new capabilities for the fields of medical and rehabilitation robotics, artificial intelligence, and soft electronics. Precisely programming the shape morphing and decoupling the multiresponsiveness of such robots is crucial to enable them with ample degrees of freedom and multifunctionality, while ensuring high fabrication accuracy. However, current designs featuring coupled multiresponsiveness or intricate assembly processes face limitations in executing complex transformations and suffer from a lack of precision. Therefore, we propose a one-stepped strategy to program multistep shape-morphing soft millirobots (MSSMs) in response to decoupled environmental stimuli. Our approach involves employing a multilayered elastomer and laser scanning technology to selectively process the structure of MSSMs, achieving a minimum machining precision of 30 μm. The resulting MSSMs are capable of imitating the shape morphing of plants and hand gestures and resemble kirigami, pop-up, and bistable structures. The decoupled multistimuli responsiveness of the MSSMs allows them to conduct shape morphing during locomotion, perform logic circuit control, and remotely repair circuits in response to humidity, temperature, and magnetic field. This strategy presents a paradigm for the effective design and fabrication of untethered soft miniature robots with physical intelligence, advancing the decoupled multiresponsive materials through modular tailoring of robotic body structures and properties to suit specific applications.
HDX–MS finds that partial unfolding with sequential domain activation controls condensation of a cellular stress marker
Authors: Chen Ruofan , Glauninger Hendrik , Kahan Darren N. , Shangguan Julia , Sachleben Joseph R. , Riback Joshua A. , Drummond D. Allan , Sosnick Tobin R.
Published: March 2024

Eukaryotic cells form condensates to sense and adapt to their environment [S. F. Banani, H. O. Lee, A. A. Hyman, M. K. Rosen,Nat. Rev. Mol. Cell Biol.18, 285–298 (2017), H. Yoo, C. Triandafillou, D. A. Drummond,J. Biol. Chem.294, 7151–7159 (2019)]. Poly(A)-binding protein (Pab1), a canonical stress granule marker, condenses upon heat shock or starvation, promoting adaptation [J. A. Ribacket al.,Cell168, 1028–1040.e19 (2017)]. The molecular basis of condensation has remained elusive due to a dearth of techniques to probe structure directly in condensates. We apply hydrogen–deuterium exchange/mass spectrometry to investigate the mechanism of Pab1’s condensation. Pab1’s four RNA recognition motifs (RRMs) undergo different levels of partial unfolding upon condensation, and the changes are similar for thermal and pH stresses. Although structural heterogeneity is observed, the ability of MS to describe populations allows us to identify which regions contribute to the condensate’s interaction network. Our data yield a picture of Pab1’s stress-triggered condensation, which we term sequential activation (Fig. 1A), wherein each RRM becomes activated at a temperature where it partially unfolds and associates with other likewise activated RRMs to form the condensate. Subsequent association is dictated more by the underlying free energy surface than specific interactions, an effect we refer to as thermodynamic specificity. Our study represents an advance for elucidating the interactions that drive condensation. Furthermore, our findings demonstrate how condensation can use thermodynamic specificity to perform an acute response to multiple stresses, a potentially general mechanism for stress-responsive proteins.
Gravitational waves in the circular restricted three body problem
Authors: Martin Barandiaran Mikel , Kuroyanagi Sachiko , Nesseris Savvas
Published: March 2024

The prospect of unprecedented high-quality data of gravitational waves in the upcoming decades demands a theoretical effort to optimally study and analyze the signals that next generation detectors will provide. Here we study the gravitational wave emission and related dynamics during the inspiralling phase of the Circular Restricted Three Body Problem, a modification of the conventional binary scenario in which a small third object co-rotates with the parent binary system. Specifically, we obtain analytic expressions for the emitted power, frequency variation and other dynamical variables that describe the evolution of the system. As a key highlight, we find that the presence of the third body actually slows down the coalescence of the binary, which can be partially interpreted as an effective rescaling of the binary’s chirp-mass. Our analysis assumes semi-Keplerian orbits for the particles and a highly mass asymmetric parent binary needed for the stability of orbits.
Anomaly detection of wind turbine based on norm-linear-ConvNeXt-TCN
Authors: Chen Ning , Shao Changsheng , Wang Guangbin , Wang Qiang , Zhao Zihan , Liu Xinyao
Published: March 2024

The supervisory control and data acquisition (SCADA) system of wind turbines continuously collects a large amount of monitoring data during their operation. These data contain abundant information about the operating status of the turbine components. Utilizing this information makes it feasible to provide early warnings and predict the health status of the wind turbine. However, due to the strong coupling between the various components of the wind turbine, the data exhibits complex spatiotemporal relationships, multiple state parameters, strong non-linearity, and noise interference, which brings great difficulty to anomaly detection of the wind turbine. This paper proposes a new method for detecting abnormal operating conditions of wind turbines, based on a cleverly designed multi-layer linear residual module and the improved temporal convolutional network (TCN) with a new norm-linear-ConvNeXt architecture (NLC-TCN). Initially, the NLC-TCN deep learning reconstruction model is trained with historical data of normal behavior to extract the spatiotemporal features of state parameters under normal operational conditions. Subsequently, the condition score of the unit is determined by calculating the average normalized root mean square error between the reconstructed data and actual data. The streaming peaks-over-threshold real-time calculation of the anomaly warning threshold, based on extreme value theory, is then used for preliminary fault monitoring. Moreover, by shielding the fault alarm for low wind speeds and implementing a continuous delay perception mechanism, issues related to wind speed fluctuations and internal and external interference are addressed, enabling early warning for faulty units. Finally, the effectiveness and reliability of the proposed method are validated through comparative experiments using actual offshore wind farm SCADA data. The performance of the proposed method surpasses that of other compared methods. Additionally, the results of the proposed method were evaluated using the uniform manifold approximation and projection dimensionality reduction technique and kernel density estimation.
Temperature coefficient of resistance and thermal boundary conductance determination of ruthenium thin films by micro four-point probe
Authors: Beltrán-Pitarch Braulio , Guralnik Benny , Borup Kasper A , Adelmann Christoph , Hansen Ole , Pryds Nini , Petersen Dirch H
Published: March 2024

Accurate characterization of the temperature coefficient of resistance (α
TCR) of electrically conductive materials is pertinent for reducing self-heating in electronic devices. In-situ non-destructive measurements of α
TCR using the micro four-point probe (M4PP) technique have previously been demonstrated on platinum (Pt) thin films deposited on fused silica, assuming the thermal conductivity of the substrate as known. In this study, we expand the M4PP method to obtain the α
TCR on industrially relevant stacks, comprising ruthenium (Ru) thin films (3.3 nm and 5.2 nm thick) deposited on bulk silicon (Si), separated by a 90 nm SiO2 spacer. The new M4PP methodology allows simultaneous determination of both α
TCR and the total thermal boundary conductance (G
TBC) between the metallic film and its substrate. We measured the α
TCR and the G
TBC to be 542 ± 18 ppm K−1 and 15.6 ± 1.3 MW m−2K−1 for 3.3 nm Ru, and 982 ± 46 ppm K−1 and 19.3 ± 2.3 MW m−2K−1 for 5.2 nm Ru. This is in good agreement with independent measurements of α
TCR. Our methodology demonstrates the potential of M4PP to characterize thermal properties of metallic thin films used in semiconductor technology.
A study on the high power microwave effects of PIN diode limiter based on deep learning algorithm
Authors: Chen Huikai , Gao Wenze , Zhao Yinfen , Wang Shulong , Yan Xingyuan , Zhou Hao , Chen Shupeng , Liu Hongxia
Published: March 2024

PIN diodes, due to their simple structure and variable resistance characteristics under high-frequency high-power excitation, are often used in radar front-end as limiters to filter high power microwaves (HPM) to prevent its power from entering the internal circuit and causing damage. This paper carries out theoretical derivation and research on the HPM effects of PIN diodes, and then uses an optimized neural network algorithm to replace traditional physical modeling to calculate and predict two types of HPM limiting indicators of PIN diode limiters. We proposes a neural network model for each of the following two prediction scenarios: in the scenario of time-junction temperature curves under different HPM irradiation, the weighted mean squared error (MSE) between the predicted values from the test dataset and the simulated values is below 0.004. While in predicting PIN limiter’s power limitation threshold, insertion loss, and maximum isolation under different HPM irradiation, the MSE of the test set prediction values and simulation values are all less than 0.03. The method proposed in this research, which applies an optimized neural network algorithm to replace traditional physical modeling algorithms for studying the high-power microwave effects of PIN diode limiters, significantly improves the computational and simulation speed, reduces the calculation cost, and provides a new method for studying the high-power microwave effects of PIN diode limiters.
On electromagnetic turbulence and transport in STEP
Authors: Giacomin M , Kennedy D , Casson F J , C J Ajay , Dickinson D , Patel B S , Roach C M
Published: March 2024

In this work, we present first-of-their-kind nonlinear local gyrokinetic (GK) simulations of electromagnetic turbulence at mid-radius in the burning plasma phase of the conceptual high-β, reactor-scale, tight-aspect-ratio tokamak Spherical Tokamak for Energy Production (STEP). A prior linear analysis in Kennedyet al(2023Nucl. Fusion63126061) reveals the presence of unstable hybrid kinetic ballooning modes (KBMs), where inclusion of the compressional magnetic field fluctuation,δB∥, is crucial, and subdominant microtearing modes (MTMs) are found at binormal scales approaching the ion-Larmor radius. Local nonlinear GK simulations on the selected surface in the central core region suggest that hybrid KBMs can drive large turbulent transport, and that there is negligible turbulent transport from subdominant MTMs when hybrid KBMs are artificially suppressed (through the omission ofδB∥). Nonlinear simulations that include perpendicular equilibrium flow shear can saturate at lower fluxes that are more consistent with the available sources in STEP. This analysis suggests that hybrid KBMs could play an important role in setting the turbulent transport in STEP, and possible mechanisms to mitigate turbulent transport are discussed. Increasing the safety factor or the pressure gradient strongly reduces turbulent transport from hybrid KBMs in the cases considered here. Challenges of simulating electromagnetic turbulence in this high-βregime are highlighted. In particular the observation of radially extended turbulent structures in the absence of equilibrium flow shear motivates future advanced global GK simulations that includeδB∥.
Multi-scale recurrent transformer model for predicting KSTAR PF superconducting coil temperature
Authors: Kwon Giil , Lee Hyunjung
Published: March 2024

Superconducting coils play a critical role in a superconducting-based nuclear fusion device. As the temperature of superconducting magnets increases with a change in current, it is important to predict their temperature to prevent excessive temperature rise of coils and operate them efficiently. We present multi-scale recurrent transformer system, a deep learning model for forecasting the temperature of superconducting coils. Our system recurrently predicts future temperature data of the superconducting coil using the previous data obtained from a multi-scale Korea Superconducting Tokamak Advanced Research poloidal field coil dataset and latent data calculated from previous time step. We apply a multi-scale temperature downsampling approach in our model to effectively learn both the details and the overall structure of the temperature data. We demonstrate the effectiveness of our model through experiments and comparisons with existing models.