bluuebunny/crossref_metadata_2025 huggingface dataset:
Rim dynamics and instability of a curved liquid sheet formed by jet impinging on a circular plane
Authors: Kang Tianyu , Yu Qingbo , Liu Zhongyuan , Tao Shengkai
Published: September 2024

The free liquid sheet formed by jet impingement often has a certain bending, and this paper focuses on the influence of this bending on the rim dynamics and instability. The derivations of the rim retraction and the flow trajectory of the curved liquid sheet show that the length of the flow trajectory reaching the equator is the same as the Taylor–Culick radius representing the rim retraction equilibrium. It is inferred that the stable radius corresponding to the curved trajectory must be less than the Taylor–Culick radius, that is, a curved liquid sheet cannot reach the stable position by the rim retraction equilibrium alone. Experimental results confirm that the greater the degree of liquid sheet bending, the farther the stable radius from the Taylor–Culick radius. In addition to the rim retraction, the rim can remain in a stable position with the help of the fingerlike cusp, formed due to instability, deflecting liquid momentum. The dispersion equation of rim instability is derived to obtain the maximum growth rate of disturbance and corresponding wavelength. The surface tension is the main driving force of rim instability, and the liquid flow from the liquid sheet into the rim inhibits the rim instability. With increasing We, the decreasing local liquid sheet thickness increases the growth rate of disturbance and decreases the instability wavelength, which causes the rim to destabilize at a smaller rim radius, resulting in the corresponding decrease in droplet radius. The experimental results agree well with the theoretical prediction.
East rarely meets West: a revised delimitation for Pultenaea (Fabaceae: Mirbelieae) with reinstatement of Euchilus and three new genera from south-west Western Australia
Authors: Barrett Russell L. , Clugston James A. R. , Orthia Lindy A. , Cook Lyn G. , Crisp Michael D. , Lepschi Brendan J. , Macfarlane Terry D. , Weston Peter H. , Wilkins Carolyn F.
Published: September 2024

Circumscription of the large genus Pultenaea Sm. has been contentious since shortly after description. We draw on recently generated phylogenomic data to provide a fully resolved phylogeny of Pultenaea and related genera based on near-complete species level sampling for the genus. Phylogenomic data divide Pultenaea sens. lat. into five independent lineages, corresponding to previously identified clades, that we recognise as distinct genera. Pultenaea sens. str. contains most of the currently recognised species and as circumscribed here, all of the species are endemic to eastern Australia except for P. tenuifolia R.Br. & Sims that extends across the Nullarbor into Western Australia. The genus Euchilus R.Br. is reinstated for eight species, all endemic to south-west Western Australia except for E. elachistus (F.Muell.) R.L.Barrett & Orthia that also occurs in South Australia. Three new genera are described, with all of the constituent species endemic to south-west Western Australia: Grievea R.L.Barrett, Clugston & Orthia, with two species, Jennata R.L.Barrett, Clugston & Orthia, with nine species and Loricobbia R.L.Barrett, Clugston & Orthia with six species. Pultenaea adunca Turcz. remains unplaced but we exclude this species from our concept of Pultenaea. Twenty-one new combinations are made: Euchilus aridus (E.Pritz.) R.L.Barrett & Orthia, E. calycinus subsp. proxenus (Orthia & Chappill) Orthia & R.L.Barrett, E. daena (Orthia & Chappill) Orthia & R.L.Barrett, E. elachistus (F.Muell.) R.L.Barrett & Orthia, Grievea brachytropis (Benth. ex Lindl.) R.L.Barrett & Orthia, G. craigiana (C.F.Wilkins, Orthia & Crisp) Orthia & R.L.Barrett, Jennata brachyphylla (Turcz.) R.L.Barrett & Clugston, J. empetrifolia (Meisn.) R.L.Barrett & Clugston, J. ericifolia (Benth.) R.L.Barrett & Clugston, J. indira (Orthia & Crisp) Orthia & R.L.Barrett, J. indira subsp. monstrosita (Orthia) Orthia & R.L.Barrett, J. indira subsp. pudoides (Orthia) Orthia & R.L.Barrett, J. radiata (H.B.Will.) R.L.Barrett & Clugston, J. strobilifera (Meisn.) R.L.Barrett & Clugston, J. verruculosa (Turcz.) R.L.Barrett & Clugston, Loricobbia aspalathoides (Meisn.) R.L.Barrett & T.D.Macfarl., L. ochreata (Meisn.) R.L.Barrett & T.D.Macfarl., L. pauciflora (M.B.Scott) R.L.Barrett & T.D.Macfarl., L. pinifolia (Meisn.) R.L.Barrett & T.D.Macfarl., L. reticulata (Sm.) R.L.Barrett & T.D.Macfarl. and L. skinneri (F.Muell.) R.L.Barrett & T.D.Macfarl.
High-resolution stereolithography: Negative spaces enabled by control of fluid mechanics
Authors: Coates Ian A. , Pan William , Saccone Max A. , Lipkowitz Gabriel , Ilyin Dan , Driskill Madison M. , Dulay Maria T. , Frank Curtis W. , Shaqfeh Eric S. G. , DeSimone Joseph M.
Published: September 2024

Stereolithography enables the fabrication of three-dimensional (3D) freeform structures via light-induced polymerization. However, the accumulation of ultraviolet dose within resin trapped in negative spaces, such as microfluidic channels or voids, can result in the unintended closing, referred to as overcuring, of these negative spaces. We report the use of injection continuous liquid interface production to continuously displace resin at risk of overcuring in negative spaces created in previous layers with fresh resin to mitigate the loss of Z-axis resolution. We demonstrate the ability to resolve 50-μm microchannels, breaking the historical relationship between resin properties and negative space resolution. With this approach, we fabricated proof-of-concept 3D free-form microfluidic devices with improved design freedom over device material selection and resulting properties.
Large Tunneling Magnetoresistance and Perfect Spin Filtering Effect in van der Waals Cu/FeX2/h-BN/FeX2/Cu (X=Cl, Br, I) Magnetic Tunnel Junctions
Authors: Dong 董 Xinlong 新龙 , Shi 师 Xiaowen 小文 , Qiao 乔 Dan 丹 , Li 李 Zeyu 泽宇 , Bai 白 Yuhao 宇浩 , Qiao 乔 Zhenhua 振华 , Xu 许 Xiaohong 小红
Published: September 2024

The two-dimensional magnetic van der Waals heterojunctions have opened unprecedented opportunities to explore new physics due to their potential for spintronic applications. Here, combing density functional theory with non-equilibrium Green’s function technique, we systematically investigate the spin-polarized transport properties of Cu/FeX2/h-BN/FeX2/Cu (X = Cl, Br, I) magnetic tunnel junctions (MTJs). It is found that the maximum tunneling magnetoresistance of Cu/FeCl2/h-BN/FeCl2/Cu, Cu/FeBr2/h-BN/FeBr2/Cu, and Cu/FeI2/h-BN/FeI2/Cu MTJs can reach 3443%, 3069%, and 1676%, respectively. In the parallel state, the resistance area products at zero bias for Cu/FeCl2/h-BN/FeCl2/Cu, Cu/FeBr2/h-BN/FeBr2/Cu, and Cu/FeI2/h-BN/FeI2/Cu MTJs are 0.92, 0.47, and 0.32 Ω⋅μm2, respectively. More interestingly, our results indicate that Cu/FeX2/h-BN/FeX2/Cu (X = Cl, Br, I) MTJs can realize spin filtering effect, while Cu/FeCl2/h-BN/FeCl2/Cu and Cu/FeI2/h-BN/FeI2/Cu MTJs exhibit negative differential resistance. Our results demonstrate that large tunneling magnetoresistance, negative differential resistance effect, low resistance area product as well as excellent spin filtering effect coexist in Cu/FeCl2/h-BN/FeCl2/Cu and Cu/FeI2/h-BN/FeI2/Cu MTJs, and that the feasible tunability of such a kind of van der Waals magnetic tunnel junctions is beneficial to designing next-generation logic devices.
Camera calibration method based on ellipse eccentricity compensation
Authors: Zhao Chengli , Zhao Zhangyan , Liu Yang
Published: September 2024

In the field of visual measurement, camera calibration is the first step and an important step in determining the accuracy of the measurement. Achieving rapid and accurate camera calibration has been a significant focus of research among scholars. Therefore, a high-precision camera calibration framework based on ellipse eccentricity compensation is proposed. In the first step, the Canny algorithm is used to detect ellipse edges. In the second step, a high-precision fitting of the ellipse is accomplished by a weighted fitting method. In the third step, the initial calibration parameters are calculated by using the coordinates of the elliptical center. Subsequently, the eccentricity deviation of the ellipse is compensated based on the initial calibration parameters. The updated coordinates are then used to recalculate the calibration parameters. This iterative process is repeated using an improved swarm intelligence optimization algorithm until the error is below the threshold or the number of iterations is reached. Simulations and experiments are used to verify the proposed method. The results show that the proposed method has high accuracy and stability, and can be widely used in engineering.
Understanding error rejection of differential impedance spectroscopy for the in situ characterization of highly conductive fluids
Authors: Doppelhammer Nikolaus , Voglhuber-Brunnmaier Thomas , Vandenabeele Dries , Jakoby Bernhard , Breynaert Eric
Published: September 2024

Differential impedance spectroscopy (DIS) can offer distinct advantages over conventional impedance spectroscopy (IS), particularly for the in situ characterization of highly conductive, corrosive fluids. To enhance the understanding of DIS and determine the conditions under which this method is preferable over conventional IS with fixed electrode positions, error calculations were performed. Two scenarios were analyzed, one accounting solely for random instrument errors and the other including random errors as well as systematic errors from a serial offset impedance. Our analyses reveal that while permittivity measurements of highly conductive media remain challenging regardless of whether a conventional or differential impedance approach is used, DIS enables highly accurate conductivity measurements across a wide frequency and conductivity range. Studying different cell dimensions with equal cell constants revealed that despite the increased influence of systematic errors at small scales, conductivity can still be accurately measured, underscoring the applicability of DIS for microfluidic applications. Other potential parasitic effects, such as those arising from the electromagnetic skin effect, stray capacitances, electrode size, and temperature gradients, are discussed, providing a comprehensive framework for sample characterization with DIS.
Continuity of the Lyapunov exponents of non-invertible random cocycles with constant rank
Authors: Duarte Pedro , Freijo Catalina
Published: September 2024

In this paper we establish uniform large deviations estimates of exponential type and Hölder continuity of the Lyapunov exponents for random non-invertible cocycles with constant rank.
Template-based synergy extrapolation analysis for prediction of muscle excitations
Authors: Li Kaitai , Wang Daming , Chen Zuobing , Guo Dazhi , Pan Shuyi , Liu Hui , Zhou Congcong , Ye Xuesong
Published: September 2024

Objective. Accurate prediction of unmeasured muscle excitations can reduce the required wearable surface electromyography (sEMG) sensors, which is a critical factor in the study of physiological measurement. Synergy extrapolation uses synergy excitations as building blocks to reconstruct muscle excitations. However, the practical application of synergy extrapolation is still limited as the extrapolation process utilizes unmeasured muscle excitations it seeks to reconstruct. This paper aims to propose and derive methods to provide an avenue for the practical application of synergy extrapolation with non-negative matrix factorization (NMF) methods. Approach. Specifically, a tunable Gaussian–Laplacian mixture distribution NMF (GLD-NMF) method and related multiplicative update rules are derived to yield appropriate synergy excitations for extrapolation. Furthermore, a template-based extrapolation structure (TBES) is proposed to extrapolate unmeasured muscle excitations based on synergy weighting matrix templates totally extracted from measured sEMG datasets, improving the extrapolation performance. Moreover, we applied the proposed GLD-NMF method and TBES to selected muscle excitations acquired from a series of single-leg stance tests, walking tests and upper limb reaching tests. Main results. Experimental results show that the proposed GLD-NMF and TBES could extrapolate unmeasured muscle excitations accurately. Moreover, introducing synergy weighting matrix templates could decrease the number of sEMG sensors in a series of experiments. In addition, verification results demonstrate the feasibility of applying synergy extrapolation with NMF methods. Significance. With the TBES method, synergy extrapolation could play a significant role in reducing data dimensions of sEMG sensors, which will improve the portability of sEMG sensors-based systems and promotes applications of sEMG signals in human–machine interfaces scenarios.
The impact of controlled breathing on autonomic nervous system modulation: analysis using phase-rectified signal averaging, entropy and heart rate variability
Authors: Uryga Agnieszka , Najda Mikołaj , Berent Ignacy , Mataczyński Cyprian , Urbański Piotr , Kasprowicz Magdalena , Buchner Teodor
Published: September 2024

Objective. The present study investigated how breathing stimuli affect both non-linear and linear metrics of the autonomic nervous system (ANS). Approach. The analysed dataset consisted of 70 young, healthy volunteers, in whom arterial blood pressure (ABP) was measured noninvasively during 5 min sessions of controlled breathing at three different frequencies: 6, 10 and 15 breaths min−1. CO2 concentration and respiratory rate were continuously monitored throughout the controlled breathing sessions. The ANS was characterized using non-linear methods, including phase-rectified signal averaging (PRSA) for estimating heart acceleration and deceleration capacity (AC, DC), multiscale entropy, approximate entropy, sample entropy, and fuzzy entropy, as well as time and frequency-domain measures (low frequency, LF; high-frequency, HF; total power, TP) of heart rate variability (HRV). Main results. Higher breathing rates resulted in a significant decrease in end-tidal CO2 concentration (p < 0.001), accompanied by increases in both ABP (p < 0.001) and heart rate (HR, p < 0.001). A strong, linear decline in AC and DC (p < 0.001 for both) was observed with increasing breathing rate. All entropy metrics increased with breathing frequency (p < 0.001). In the time-domain, HRV metrics significantly decreased with breathing frequency (p < 0.01 for all). In the frequency-domain, HRV LF and HRV HF decreased (p = 0.038 and p = 0.040, respectively), although these changes were modest. There was no significant change in HRV TP with breathing frequencies. Significance. Alterations in CO2 levels, a potent chemoreceptor trigger, and changes in HR most likely modulate ANS metrics. Non-linear PRSA and entropy appear to be more sensitive to breathing stimuli compared to frequency-dependent HRV metrics. Further research involving a larger cohort of healthy subjects is needed to validate our observations.
Fiber coupling of partially coherent Laguerre Gaussian vortex beam in a Cassegrain antenna system
Authors: Qiao Jiawei , Shen Jiajia , Jiang Ping , Caiyang Weinan , Yang Huajun
Published: September 2024

In consideration of the importance of the partially coherent beam (PCB) in optical communication, the coupling of partially coherent Laguerre Gaussian vortex beam (PCLGVB) with single-mode fiber after passing through a Cassegrain transmitting antenna is researched. Meanwhile, the effect of atmospheric turbulence and the assembly misalignments is also considered. In the paper, the transmission of a PCLGVB through a Cassegrain transmitting antenna is mathematically modeled and the coupling efficiency is numerically calculated. And as the propagation distance increases, the coupling efficiency shows an upward trend. In the meanwhile, the PCB is more resistant to the disruptions introduced by atmospheric turbulence and misalignments. And for the coupling between PCLGVB and the single-mode fiber, as the lateral offset or tilt angle increases, the coupling efficiency remains stable in some intervals, or even appears to grow anomalously, which may provide a new idea for enhancing the coupling efficiency. Compared to the case of perfect alignment, the lateral offset of 0 with a tilt angle of 6.5° has a higher coupling efficiency of 21.35%.
“Glass-quake” in elastically loaded bulk metallic glasses
Authors: Huang 黄 Qi 琦 , Chen 陈 Kaiguo 开果 , Liu 刘 Chen 辰 , Liu 刘 Guisen 桂森 , Shao 邵 Yang 洋 , Zhao 赵 Chenlong 晨龙 , Chen 陈 Ran 然 , Bu 卜 Hengtong 亨通 , Kong 孔 Lingti 令体 , Shen 沈 Yao 耀
Published: September 2024

Amorphous solids exhibit scale-free avalanches, even under small external loading, and thus can work as suitable systems to study critical behavior and universality classes. The abundance of scale-free avalanches in the entire elastic tension regime of bulk metallic glass (BMG) samples has been experimentally observed using acoustic emission (AE) measurements. In this work, we compare the statistics of avalanches with those of earthquakes, and find that they both follow the Gutenberg–Richter law in the statistics of energies and Omori’s law of aftershock rates, and share the same characteristics in the distribution of recurrence times. These resemblances encourage us to propose the term “glass-quake” to describe avalanches in elastically loaded BMGs. Furthermore, our work echoes the potential universality of critical behavior in disordered physical systems from atomic to planetary scales, and motivates the use of elastic loaded BMGs as valuable laboratory simulators of seismic dynamics.
Non-conventional machining of SiC reinforced Aluminum metal matrix composites: A Review
Authors: Hazra Ritesh , Doloi Biswanath
Published: September 2024

Metal Matrix Composites or MMCs are among the advanced materials in which lightweight metallic matrices are combined with fibres or particles of hard ceramics as reinforcements. Due to their enhanced properties compared to the monolithic metal alloys, these materials are gaining rapid importance in aerospace, automotive, energy, defense & sports industries. Silicon Carbide reinforced Aluminum MMCs are widely used because of its low cost, good hardness & corrosion resistance properties. However, during conventional machining of these materials, the reinforcement phase causes workpiece damage, excessive tool wear and elevated cutting force owing to their high hardness and abrasive nature. To improve machinability conditions of the Al/SiC MMCs, performance of some non-conventional machining processes like Electrical Discharge Machining, Wire Electrical Discharge Machining, Electrochemical Machining, Laser Beam Machining & Abrasive Water Jet Machining were investigated over the last few decades & were found to yield very good results with promising future scopes. This review paper focuses on summarizing the machining performances, challenges encountered and suitable optimization techniques while using non-conventional machining processes for Al/SiC MMCs.
Chip morphology assessment in turning of hardened AISI 52100 steel under ZnO nanofluid environment
Authors: Abdur Rahman K M , Sethy Priyaranjan , Khatai Saswat , Kumar Ramanuj , Panda Amlana , Ranjan Mishra Rasmi , Kumar Sahoo Ashok
Published: September 2024

The chip morphology in hard turning significantly impacts tool performance influenced by factors like strain softening, machining parameters, workpiece hardness, and tool geometry. In this current study, AISI 52100 steel of hardness (∼ 55 HRC) has been taken into consideration for the hard turning experiment and a detailed chip morphology study was conducted under ZnO nanofluid MQL (Minimum quantity lubrication) condition assisted by dual nozzle set up. The influence of machining parameters such as cutting speed, feed, depth of cut, and MQL flow rate on different chip morphology criteria like chip reduction coefficient, chip curl angle, chip pitch length, chip pattern, and colour has been studied thoroughly in this investigation. From the experimental study, it was observed that CRC is influenced by the depth of cut while chip curl angle and chip pitch length are majorly influenced by feed followed by cutting speed. Helical, wavy, and spiral shape chips followed by saw-tooth formation chips were observed in the entire investigation. However, spiral chips and blue colour chips were noticed at higher feed and higher cutting speed conditions respectively.
Preface for the 12th Nordic Conference on Construction Economics and Organisation
Authors: Torp Olav , Johanne Klungseth Nora , Christoffer Gottlieb Stefan
Published: September 2024

1. Personal reflections from the editors

Arranging this conference has been an interresting journey. Two years ago, NTNU was given the opportunity to arrange and host the 12th Nordic Conference on Construction Economics and organisation on behalf of the CREON network. Having the opportunity to work with the science committee, the local organising committee, and all other contributors, including authors, co-authors, and reviewers, has been a real pleasure. We would like to thank everyone for the great efforts they have put into making this event successful.

We look forward to future cooperation in the CREON network, contributing to new knowledge on construction economics and organisation in the Nordic region and worldwide. With the development of the construction industry, with more complex projects and increasing focus on sustainability and digitalization, this knowledge is important to solve future challenges in the construction industry.

List of the 12th Nordic Conference on Construction Economics and Organisation, Conference theme and topics in the call for abstracts, Event organisation and Overview of the conference program are available in this Pdf.
Prediction of accident risk in construction projects using data on safety and quality deviations from a Norwegian company
Authors: Hjemgård Kristine
Published: September 2024

This study explores the potential of machine learning to predict the risk of accidents in construction projects. Data has been gathered from a Norwegian construction company over a period of nearly seven years, consisting of 156 projects. 46 features are constructed, primarily focusing on observations and incidents on health, safety, and environment, as well as quality deviations. Using mutual information, 20 important features are identified. These are later used to train six classification models, which are evaluated using 10-fold cross-validation. The target feature of the classification problem is the level of risk, which describes the probability of accidents for a project: low risk, risk of less severe accidents, risk of serious accidents, and risk of critical accidents. The model performances are poor compared to previous studies. This is likely a result of the amount of projects and the total number of different features used to train the models. Based on the limited data that is utilized, the results still indicate that there is a potential in some of the data, especially observations and incidents. It is suggested that incorporating project worker-related data and more project information could enhance the accuracy of predictions.
Residential Adaptive Reuse in Post-pandemic Times
Authors: Kyrö Riikka , Janson Ulla , Blixt Anna-Maria , Fredriksson Peter
Published: September 2024

In the aftermath of the Covid-19 pandemic, the accelerated shift to remote and hybrid work modes has left many office buildings vacant. Meanwhile, many cities struggle with providing housing. Adaptive reuse (AR) is the process of giving an existing building a new life, typically through an extensive renovation and refurbishment. Residential adaptative reuse specifically refers to adapting for housing purposes. The aim of this study is to shed light on opportunities and enablers for AR, specifically from the perspectives of owner/developers and contractors. A multiple case study method, utilizing a desktop approach with secondary data sources, is employed to reveal key lessons learned from real-life residential AR cases from the Nordics. We include 6 cases of residential AR, of which four are from Sweden, and two from Finland. We find that prime location and structural integrity are prerequisites for AR. Daylight, accessibility, and indoor comfort were noted to be common challenges, which were overcome by experience from previous adaptation projects, as well as good collaboration within the project team and authorities. The cultural heritage status of a building appears to both make the building more suitable for adaptation and create a challenge with risks associated with the construction works. Working within existing urban structure was noted to be a challenge for construction site logistics, as well as a nuisance to neighbors, making the support from neighbors crucial. Yet, perhaps the most striking similarity between the cases was that the adaptative reuse projects were linked to either vertical extension, or horizontally extending the project as a form of urban infill development. The findings provide a useful checklist to real estate owners, developers, and contractors considering adaptation to residential use, or bidding for AR projects. An interesting challenge warranting further research is the valuation of commercial properties with expected rental income, despite high vacancy.
Fractional-order burgers model for coral concrete creep
Authors: Cao Jian , Wang Danshen , Zou Ziyi , Tu Ning
Published: September 2024

With the rapid development of marine engineering construction, coral aggregate has been widely applied in practical engineering. Its creep characteristics must be emphasized, but only a few experimental studies have been conducted, and theoretical research has not yet been reported. In this study, based on the traditional Burgers rheological model and using the fractional order software components Able dashpot, constructs a fractional order creep model for coral concrete and provides a calculation method. Comparison shows that the traditional Burgers rheological model cannot adjust the creep rate and development degree in calculations, resulting in a large deviation between its predicted results and experimental values. However, the fractional order model established in this paper aligns with the creep development law of coral concrete, and its calculated values match well with experimental values, making it suitable for predicting the creep characteristics of coral concrete under different water-cement ratios. Sensitivity analysis of the fractional order can achieve effective control over the prediction of creep development in coral concrete in practical engineering. The fractional order creep model established in this paper can provide a basis for predicting and evaluating the long-term performance of coral concrete in practical engineering.
Large sieve inequalities with power moduli and Waring’s problem
Authors: Baier Stephan , Lynch Sean
Published: September 2024

We improve the large sieve inequality with

k

t
h

k^{\mathrm {th}}

-power moduli, for all

k
≥
4

k\ge 4

. Our method relates these inequalities to a variant of Waring’s problem with restricted

k

t
h

k^{\mathrm {th}}

-powers. Firstly, we input a classical divisor bound on the number of representations of a positive integer as a sum of two

k

t
h

k^{\mathrm {th}}

-powers. Secondly, we apply Marmon’s bound on the number of representations of a positive integer as a sum of four

k

t
h

k^{\mathrm {th}}

-powers. Thirdly, we use Wooley’s Vinogradov mean value theorem with arbitrary weights. Lastly, we state a conditional result, based on the conjectural Hardy-Littlewood formula for the number of representations of a large positive integer as a sum of

k
+
1

k+1

k

t
h

k^{\mathrm {th}}

-powers.
Comparing Two-Step Approaches to Measuring Gender Identity: The Reliability and Applications of Asking About Sex Assigned at Birth versus Transgender Self-Identification
Authors: Tordoff Diana M , Minalga Brian , Catháin Nicole Ó , Fernandez Atlas , Gross Bennie , Glick Sara N ,   the Seattle Trans and Nonbinary Sexual Health (STARS) Advisory Board
Published: September 2024

Inclusive measures of gender are critical for health equity research. This study compared the reliability and applications of two different approaches for measuring gender in response to emerging community concerns regarding the potential harms of asking about sex assigned at birth (SAAB) within transgender and gender diverse (TGD) populations. Using data from a 2021 survey of LGBTQ+ people in Washington state, we compared approaches for measuring gender via a two-step question that collected data on: (1) current gender and SAAB versus (2) current gender and transgender self-identification. Among 2,275 LGBTQ+ participants aged 9-81, 63% were cisgender, 35% TGD, and 2% were not categorized. There was near perfect agreement between the two methods in their ability to identify TGD participants (percent agreement=99.7%, unweighted Cohen’s Kappa=0.99). Among gender diverse participants, stratification by SAAB revealed differences in sexual health outcomes, while stratification by transgender self-identification revealed differences in access to gender-affirming care and lifetime experiences of discrimination. Ascertaining SAAB may be most useful for identifying sexual health disparities while transgender self-identification may better illuminate healthcare needs and social determinants of health among TGD people. Researchers and public health practitioners should critically consider the acceptability and relevance of SAAB questions to their research goals.
Higher-order correction of persistent batch effects in correlation networks
Authors: Micheletti Soel , Schlauch Daniel , Quackenbush John , Ben Guebila Marouen
Published: September 2024

Motivation

Systems biology analyses often use correlations in gene expression profiles to infer co-expression networks that are then used as input for gene regulatory network inference or to identify functional modules of co-expressed or putatively co-regulated genes. While systematic biases, including batch effects, are known to induce spurious associations and confound differential gene expression analyses (DE), the impact of batch effects on gene co-expression has not been fully explored. Methods have been developed to adjust expression values, ensuring conditional independence of mean and variance from batch or other covariates for each gene, resulting in improved fidelity of DE analysis. However, such adjustments do not address the potential for spurious differential co-expression (DC) between groups. Consequently, uncorrected, artifactual DC can skew the correlation structure, leading to the identification of false, non-biological associations, even when the input data are corrected using standard batch correction.

Results

In this work, we demonstrate the persistence of confounders in covariance after standard batch correction using synthetic and real-world gene expression data examples. We then introduce Co-expression Batch Reduction Adjustment (COBRA), a method for computing a batch-corrected gene co-expression matrix based on estimating a conditional covariance matrix. COBRA estimates a reduced set of parameters expressing the co-expression matrix as a function of the sample covariates, allowing control for continuous and categorical covariates. COBRA is computationally efficient, leveraging the inherently modular structure of genomic data to estimate accurate gene regulatory associations and facilitate functional analysis for high-dimensional genomic data.

Availability and implementation

COBRA is available under the GLP3 open source license in R and Python in netZoo (https://netzoo.github.io).
KnotResolver: tracking self-intersecting filaments in microscopy using directed graphs
Authors: Khatri Dhruv , Yadav Shivani A , Athale Chaitanya A
Published: September 2024

Motivation

Quantification of microscopy time series of in vitro reconstituted motor-driven microtubule transport in “gliding assays” is typically performed using computational object tracking tools. However, these are limited to non-intersecting and rod-like filaments.

Results

Here, we describe a novel computational image-analysis pipeline, KnotResolver, to track image time series of highly curved self-intersecting looped filaments (knots) by resolving cross-overs. The code integrates filament segmentation and cross-over or “knot” identification based on directed graph representation, where nodes represent cross-overs and edges represent the path connecting them. The graphs are mapped back to contours and the distance to a reference minimized. The accuracy of contour detection is sub-pixel with a robustness to noise. We demonstrate the utility of KnotResolver by automatically quantifying “flagella-like” curvature dynamics and wave-like oscillations of clamped microtubules in a “gliding assay.”

Availability and implementation

The MATLAB-based source code is released as OpenSource and is available at https://github.com/CyCelsLab/MTKnotResolver.
Age and visual cortex inhibition: a TMS-MRS study
Authors: Simmonite Molly , Khammash Dalia , Michon Katherine J , Hamlin Abbey , Taylor Stephan F , Vesia Michael , Polk Thad A
Published: September 2024

Paired-pulse transcranial magnetic stimulation is a valuable tool for investigating inhibitory mechanisms in motor cortex. We recently demonstrated its use in measuring cortical inhibition in visual cortex, using an approach in which participants trace the size of phosphenes elicited by stimulation to occipital cortex. Here, we investigate age-related differences in primary visual cortical inhibition and the relationship between primary visual cortical inhibition and local GABA+ in the same region, estimated using magnetic resonance spectroscopy. GABA+ was estimated in 28 young (18 to 28 years) and 47 older adults (65 to 84 years); a subset (19 young, 18 older) also completed a paired-pulse transcranial magnetic stimulation session, which assessed visual cortical inhibition. The paired-pulse transcranial magnetic stimulation measure of inhibition was significantly lower in older adults. Uncorrected GABA+ in primary visual cortex was also significantly lower in older adults, while measures of GABA+ that were corrected for the tissue composition of the magnetic resonance spectroscopy voxel were unchanged with age. Furthermore, paired-pulse transcranial magnetic stimulation–measured inhibition and magnetic resonance spectroscopy–measured tissue-corrected GABA+ were significantly positively correlated. These findings are consistent with an age-related decline in cortical inhibition in visual cortex and suggest paired-pulse transcranial magnetic stimulation effects in visual cortex are driven by GABAergic mechanisms, as has been demonstrated in motor cortex.
The weighing process in patients on hemodialysis: an opportunity to improve volume management
Authors: Niknam Janosch , Mussnig Sebastian , Matthias Christoph , Waller Maximilian , Keil Nikolaus , Krenn Simon , Beige Joachim , Schneditz Daniel , Hecking Manfred
Published: September 2024

Background

Hemodialysis relies on accurate body mass (BM) assessment to determine ultrafiltration volumes, but we have not identified published practice patterns disclosing how to handle clothing mass. Here we investigated the potential impact of clothing mass on predialysis BM determination, hypothesizing that a standardized template for clothing mass estimation enhances accuracy, compared with conventional practice.

Methods

Measurements included dressed and undressed BM predialysis. A pre-established template for average clothing mass was used to approximate undressed BM from clothed measurements. Differences from undressed BM were compared using Bland–Altman plots and tested for statistical significance using Wilcoxon signed rank tests.

Results

After excluding erroneous results, data from 48 patients were analyzed. Thirty-six patients (75%) did not habitually estimate clothing mass, but used their dressed BM as the predialysis BM, while the other 12 patients (25%) reported deducting a self-estimated clothing mass from their clothed predialysis BM. The differences from undressed BM were 0.819 ± 0.462 kg and 0.342 ± 0.321 kg in these two groups, respectively, indicating that patients underestimated clothing mass. Using the template to deduct clothing mass from clothed predialysis BM, these differences could be reduced to 0.197 ± 0.220 kg and 0.133 ± 0.135 kg, respectively. The average differences using the patient-reported BM and the template-based BM made up 39.4% and 8.6% of the average subsequent ultrafiltration volume, respectively, suggesting that potential overestimation of the actual ultrafiltration volume could be reduced.

Conclusion

A standardized template for clothing mass may be useful to derive representative predialysis BM, leading to more precise ultrafiltration calculation. Exact BM determination might improve volume management in hemodialysis.
Beyond directed hypergraphs: heterogeneous hypergraphs and spectral centralities
Authors: Contreras-Aso Gonzalo , Criado Regino , Romance Miguel
Published: September 2024

The study of hypergraphs has received a lot of attention over the past few years, however up until recently there has been no interest in systems where higher order interactions are not undirected. In this article, we introduce the notion of heterogeneous hypergraphs from an algebraic point of view, which have traditional directed hypergraphs as a particular case. We furthermore analytically study the spectral centralities associated to some types of heterogeneous hypergraphs, extending previously defined eigenvector-like centrality measures to this new realm. We supplement the analytical arguments with some numerical comparisons of pairwise and higher order rankings, and we construct directed higher order networks from real data, which we then use for discussion and analysis.
How to conduct clinical research in cardiovascular imaging: a primer for clinical cardiologists and researchers—a statement of the European Association of Cardiovascular Imaging (EACVI) of the ESC
Authors: Muraru Denisa , Pontone Gianluca , Jurcut Ruxandra , Magne Julien , Donal Erwan , Stankovic Ivan , Anagnostopoulos Constantinos , Bartko Philipp E , Bijnens Bart , Fontana Marianna , Galli Elena , Michalski Blazej , Perazzolo Marra Martina , Pezel Théo , Rossi Alexia , Smiseth Otto A , Van de Veire Nico , Edvardsen Thor , Petersen Steffen E , Cosyns Bernard , Andreini Daniele , Bertrand Philippe , Delgado Victoria , Dweck Marc , Haugaa Kristina , Keenan Niall , Marwick Thomas H , Neglia Danilo
Published: September 2024

This statement from the European Association of Cardiovascular Imaging (EACVI) of the ESC aims to address the fundamental principles that guide clinical research in the field of cardiovascular imaging. It provides clinical researchers, cardiology fellows, and PhD students with a condensed, updated, and practical reference document to support them in designing, implementing, and conducting imaging protocols for clinical trials. Although the present article cannot replace formal research training and mentoring, it is recommended reading for any professional interested in becoming acquainted with or participating in clinical trials involving cardiovascular imaging.
Long-term outcomes of cardiogenic shock and cardiac arrest complicating ST-elevation myocardial infarction according to timing of occurrence
Authors: Kanhouche Gabriel , Nicolau Jose Carlos , de Mendonça Furtado Remo Holanda , Carvalho Luiz Sérgio , Dalçoquio Talia Falcão , Pileggi Brunna , de Sa Marchi Mauricio Felippi , Abi-Kair Pedro , Lopes Neuza , Giraldez Roberto Rocha , Baracioli Luciano Moreira , Lima Felipe Gallego , Hajjar Ludhmila Abrahão , Filho Roberto Kalil , de Brito Junior Fábio Sandoli , Abizaid Alexandre , Ribeiro Henrique Barbosa
Published: September 2024

Aims

Cardiogenic shock (CS) and cardiac arrest (CA) are serious complications in ST-elevation myocardial infarction (STEMI) patients, with lack of long-term data according to their timing of occurrence. This study sought to determine the incidence and relationship between the timing of occurrence and prognostic impact of CS and CA complicating STEMI in the long-term follow-up.

Methods and results

We conducted a retrospective analysis of consecutive STEMI patients treated between 2004 and 2017. Patients were divided into four groups based on the occurrence of neither CA nor CS, CA only, CS only, and both CA and CS (CA−CS−, CA+, CS+, and CA+CS+, respectively). Adjusted Cox regression analysis was used to assess the independent association between the CS and CA categories and mortality. A total of 1603 STEMI patients were followed for a median of 3.6 years. CA and CS occurred in the 12.2% and 15.9% of patients, and both impacted long-term mortality [adjusted hazard ratio (HR) = 2.59, 95% confidence interval (CI): 1.53–4.41, P < 0.001; HR = 3.16, 95% CI: 2.21–4.53, P < 0.001, respectively). CA+CS+ occurred in 7.3%, with the strongest association with higher mortality (adjusted HR = 5.36; 95% CI: 3.80–7.55, P < 0.001). Using flexible parametric models with B-splines, the increased mortality was restricted to the first ∼10 months. In addition, overall mortality rates were higher at all timings (all with P < 0.001), except for CA during initial cardiac catheterization (P < 0.183).

Conclusion

CS and CA complicating patients presenting with STEMI were associated with higher long-term mortality rate, especially in the first 10 months. Both CS+ and CA+ at any timeframe impacted outcomes, except for CA+ during the initial cardiac catheterization, although this will have to be confirmed in larger future studies, given the relatively small number of patients.
Shortened radiofrequency delivery time to optimize efficiency and safety of pulmonary vein isolation with the radiofrequency balloon: insights from the COLLABORATE registry
Authors: Almorad Alexandre , Rocca Domenico Giovanni Della , Del Monte Alvise , Vijgen Johan , Koopman Pieter , Worck René , Johannessen Arne , Lepièce Caroline , de Ravenstein Antoine de Meester , Strisciuglio Teresa , Poggi Sara , Stabile Giuseppe , La Greca Carmelo , Kheir Joseph Antoine , Jesel-Morel Laurence , El Haddad Milad , Hossein Amin , Audiat Charles , Scacciavillani Roberto , Pannone Luigi , de Asmundis Carlo , Chierchia Gian-Battista
Published: September 2024

Aims

Previous clinical studies on pulmonary vein isolation (PVI) with a radiofrequency balloon (RFB) reported safe and effective procedures using conventional ablation settings with 20/60 s RF delivery via posterior/anterior (PST/ANT) electrodes. The latest evidence suggests that reducing the application time to 15 s (s) on the posterior wall when facing the oesophageal region is as effective as applying 20 s. To prospectively assess whether reducing RF time on PST/ANT segments to 15/45 s can ensure sufficient quality of lesion metrics and compare the new shortened ablation settings with the conventional one in terms of safety, and effectiveness at 1-year.

Methods and results

A total of 641 patients from seven European centres were enrolled in a collaborative registry, with 374 in the conventional RF delivery group and 267 in the shortened RF delivery group. Procedural outcomes, lesion metrics, and safety profiles were assessed and compared between the groups. Freedom of any atrial tachycarrythmias at one year was 85.4% and 88.2% in the SHRT and CONV groups, respectively. The shortened RF delivery strategy was associated with significantly shorter procedure times (median 63.5 vs. 96.5 min, P < 0.001) and shortened fluoroscopy exposure (median 10.0 vs. 14.0 min, P < 0.001) compared to conventional delivery. Efficacy metrics, including first-pass isolation rates and time to isolation, were comparable between groups. Shortened RF delivery was associated with a lower incidence of procedural complications (1.4% vs. 5.3%, P = 0.04) and optimized thermal characteristics.

Conclusion

Analyses from the COLLABORATE registry demonstrate that shortening RF energy delivery times to 15/45 s (PST/ANT) during PVI with the RFB resulted in comparable freedom from recurrent atrial tachyarrhythmia compared to conventional delivery times with comparable efficiency and safety.
In-depth Analysis of the HIV Reservoir Confirms Effectiveness and Safety of Dolutegravir/Lamivudine in a Phase 4 Randomized Controlled Switch Trial (RUMBA)
Authors: De Scheerder Marie-Angélique , Degroote Sophie , Delporte Mareva , Kiselinova Maja , Trypsteen Wim , Vincke Lara , De Smet Evelien , Van Den Eeckhout Bram , Schrooyen Loïc , Verschoore Maxime , Muccini Camilla , Vanherrewege Sophie , Caluwe Els , De Buyser Stefanie , Gerlo Sarah , Blomme Evy , Vandekerckhove Linos
Published: September 2024

Background

Reducing the number of active compounds for lifelong human immunodeficiency virus (HIV) treatment is of interest, especially to reduce potential long-term side effects. So far, available data assessing viral control support the robustness and safety of 2DR (2-drug regimen) antiretroviral therapy compared to 3DR. However, further in-depth investigations of the viral reservoirs are mandatory to guarantee long-term safety of these regimens regarding stable intact HIV-1 DNA copies, HIV-1 RNA transcripts, and sustained immunological control.

Methods

The RUMBA study is the first prospective randomized controlled trial evaluating the impact of switch from 3DR to 2DR on the viral reservoir. Participants on any stable second-generation integrase strand transfer inhibitor-based 3DR regimen with HIV-1 RNA < 50 copies/mL plasma for at least 3 months were randomized to switch to dolutegravir/lamivudine (DTG/3TC, n = 89) or to switch or stay on bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF, n = 45). After 48 weeks, virological, immunological, and metabolic parameters were evaluated.

Results

We did not observe a significant difference in change over time in the mean number of intact HIV-1 DNA copies/million CD4+ T cells with DTG/3TC compared to B/F/TAF. There was no evidence in this study that switching to DTG/3TC increased the active reservoir by HIV-1 transcription. No significant changes in proinflammatory cytokines or major immune cell subsets were observed. Changes in exhaustion and activation of specific cellular subsets were small and bidirectional. Metabolic outcomes are similar between the treatment regimens.

Conclusions

This study confirms the safety of DTG/3TC compared to B/F/TAF through viral control after in-depth investigations of the intact HIV-1 reservoir, HIV-1 transcription, and inflammatory markers.

Clinical Trials Registration

NCT04553081.
Exploring native arsenic (As)-resistant bacteria: unveiling multifaceted mechanisms for plant growth promotion under As stress
Authors: Yan Yaoyao , Chang Wenying , Tian Peili , Chen Jiying , Jiang Jiayin , Dai Xianzhu , Jiang Tao , Luo Feng , Yang Caiyun
Published: September 2024

Aims

This study explores the plant growth-promoting effect (PGPE) and potential mechanisms of the arsenic (As)-resistant bacterium Flavobacterium sp. A9 (A9 hereafter).

Methods and results

The influences of A9 on the growth of Arabidopsis thaliana, lettuce, and Brassica napus under As(V) stress were investigated. Additionally, a metabolome analysis was conducted to unravel the underlying mechanisms that facilitate PGPE. Results revealed that A9 significantly enhanced the fresh weight of Arabidopsis seedlings by 62.6%–135.4% under As(V) stress. A9 significantly increased root length (19.4%), phosphorus (25.28%), chlorophyll content (59%), pod number (24.42%), and weight (18.88%), while decreasing As content (48.33%, P ≤ .05) and oxidative stress of Arabidopsis. It also significantly promoted the growth of lettuce and B. napus under As(V) stress. A9 demonstrated the capability to produce ≥31 beneficial substances contributing to plant growth promotion (e.g. gibberellic acid), stress tolerance (e.g. thiamine), and reduced As accumulation (e.g. siderophores).

Conclusions

A9 significantly promoted the plant growth under As stress and decreased As accumulation by decreasing oxidative stress and releasing beneficial compounds.