bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupled Motion Analysis of a Ship-Shaped Floater and the Cold-Water Pipe for OTEC Implementation
Authors: Adiputra Ristiyanto , Imam Firdaus Muhamad , Firdaus Nurman
Published: August 2024

Ocean Thermal Energy Conversion (OTEC) utilizes the temperature difference between warm surface seawater and cold deep seawater to produce electricity. The system demands the installation of a cold-water pipe (CWP) to deliver the deep cold seawater into the plantship from a water depth of around 400–800 m in free-hanging conditions. Considering this novel condition, the present paper focuses on how the CWP affects the dynamic motion of the plantship to ensure its global stability. The main dimensions of the plantship and the cold-water pipe were adapted from the previous study. The analysis is conducted experimentally using the scaled model in a beam sea and head sea for the regular and irregular waves. The comparison results are analyzed based on the obtained response amplitude operator response in the time series of each case configuration where the floater is set with or without the CWP. Overall, the CWP installation changes the system’s natural frequency and stabilizes the floater’s motion, especially for the roll motion. In contrast, the installation effect is insignificant for pitch and heave motions regardless of the wave direction.
Computational Modelling of Repetitive Raindrop Impact and Resulting Fatigue Damage in Wind Turbine Blades
Authors: Kuthe Nikesh , Ahmad Suhail , Mahajan Puneet , Mishnaevsky Leon
Published: August 2024

Computational modelling of repetitive raindrop impact and predicting the ensuing damage in the coating and substrate due to fatigue is an essential step in determining the life of the wind turbine blade. The blade is multi-layered with a viscoelastic coating layer, a viscoelastic putty layer, and an elastic composite substrate with an interface between the layers. The damage usually takes the form of erosion of the coating and debonding at the various interfaces between the layers of the wind turbine blade.

The modelling of impact and damage involves several steps beginning with generating a stochastic rain scenario which provides information on raindrop size distribution and velocity hitting a volume of the blade. A Coupled Eulerian-Lagrangian (CEL) analysis of a single raindrop and a representative region of the blade provides impact forces on and resulting stresses in the blade. The CEL analysis is repeated for drops of different diameters to generate a library of stresses. This library, combined with a stochastic rain scenario, generates stresses at any location of the representative blade due to the repetitive impact of different-sized raindrops hitting arbitrary locations. Continuum damage mechanics is used to predict the damage evolution in the coating, and when damage reaches a critical value in any element within the developed finite element model of the multilayered blade sample represents the erosion of the coating. A cohesive zone model for fatigue debonding is employed for interfaces between coating, putty, and composite substrate. Both the Continuum damage mechanics model and a Cohesive zone model for fatigue are implemented through a user-defined subroutine in ABAQUS/Explicit.

Using the model, the interaction between erosion and debonding is studied. Using the properties of materials from the literature, the analysis shows that damage always initiates from the bottom portion of the coating layer close to the adhesive interface. This eventually creates displacement jumps at the interface of coating and putty, causing damage initiation at the interfaces. Repetitive raindrop impact of different sizes at arbitrary locations causes damage accumulation and propagation faster at the interface, finally damaging the coating layer.
Analysis on Vibration Suppression Performance of an Attached Acoustic Black Hole Composite Beam
Authors: Liu Xinru , Fu Junyong , Wan Zhiwei , Li Tianyun , Zhu Xiang
Published: August 2024

Attaching damping to structures is a common vibration suppression measure. Different from attaching uniform thickness damping, this paper proposes an acoustic black hole damping attached to a beam. There is an internal cavity between the beam and the damping layer. The thickness of the internal cavity is designed to vary according to a power index gradient, forming an attached acoustic black hole composite beam. Combined with the energy and virtual spring method, the theoretical model of the ABH beam following the Euler-Bernoulli beam theory is established to calculate its vibrational response. The vibration displacement response of the ABH beam is calculated using the finite element method again. The correctness of the theoretical model is confirmed by contrasting the theoretical results with the finite element results. From the comparison, it can be found that the peak frequency of the vibration displacement level at the output end of the ABH beam moves toward the higher frequency, and the peak response value is lower compared to that of the uniformly damped beam. The attenuation frequency interval shifts to the higher frequency in the vibration displacement transfer response curve. It can be concluded that the ABH beam exhibits better vibration suppression performance than that of the uniformly damped beam with identical damping thickness.
Reliability of Offshore Structures – Requirements to and Limitations of Calibrated Deterministic Code Design and Assessment Approaches
Authors: Tychsen Jesper , Zeeberg Allan , Nielsen Jørgen S. , Cholley Jean-Marc
Published: August 2024

This paper uses a new and validated SRA model based on Monte Carlo simulations to assess the performance of existing design and assessment approaches for offshore structures. Generic structures are designed to meet the ISO 19902 [5] code requirements in ULS and ALS limit states at three sites in the Danish North Sea sector. We then run the Monte Carlo time domain simulation to obtain the response statistics and evaluate the annual failure probability for each failure mechanism within each generic model. Looking across the range of failure mechanisms, generic structures, and sites (water depth) the performance of the ISO 19902 design approach can be evaluated. We also use the SRA model and the generic structures to test the accuracy and validity of an existing (Shell 1997) SRA model [6], which outlines a SRA principle widely used for offshore reliability analysis. We will generally refer to this as the old SRA model. We examine each parameter of the model and identify the critical design assumptions and limitations.
Low-Frequency Vibration Suppression Using a Piezoelectric Metamaterial Beam With Tunable Band Gap
Authors: Zhong Kexin , Wan Zhiwei , Liu Wenxuan , Li Tianyun , Zhu Xiang
Published: August 2024

Acoustic metamaterials have been widely studied in recent years. Generally, when a passive acoustic metamaterial for vibration suppression is designed and manufactured, its structure is difficult to adjust, and the corresponding vibration reduction characteristics are also difficult to change, which greatly limits their vibration isolation ability in complex dynamic vibration environments. In this study, we propose a piezoelectric metamaterial (PMM) beam with a tunable band gap based on Kirchhoff’s law. The structure is composed of piezoelectric ceramic materials, PMMA (Polymethyl Methacrylate), and aluminum, in which the piezoelectric ceramic materials with inductor-resistance-capacitor (LRC) shunting circuits utilize electromagnetic oscillation and electromechanical coupling properties to form a tunable local resonance (LR) band gap inside the metamaterial beam. The dispersion curve of the PMM beam was calculated using the transfer matrix method. Firstly, the energy bands of PMM beams with different compositions were compared, which demonstrated that the proposed structure had a lower frequency and wider band gap. Subsequently, the values of inductance, resistance, and capacitance in the LRC shunting circuit were changed to study the effects of its parameters on the band gap starting frequency, cutoff frequency, and bandwidth. The proposed piezoelectric metamaterial beam provided a new idea for suppressing variable vibration frequencies in the environment.
Vibration Transmission Assessment of Ship Auxiliary Machinery With Varying Mass Based on Power Flow Method
Authors: Xu Weiye , Dai Wei , Zhu Xiang , Li Tianyun , Wang Jianing , Han Wei
Published: August 2024

Compared to traditional shipboard auxiliary machinery, the mass and size of the newly designed equipment are significantly reduced, and the conventional acceleration-based evaluation method on vibration transmission from the equipment to the hull may not be suitable. This research applies a power-flow-based method for the comprehensive study of vibration transmission. Considering the intricate structures of the equipment, the vibration isolation system is initially simplified to a single degree of freedom (SDOF) model. This allows for a preliminary theoretical study. Then, a two degrees of freedom (2DOF) model is investigated to simulate the flexible base on board for comparison. Further theoretical derivations are undertaken to obtain the dynamic behavior of the system. In these two models, the equivalent method, based on equal power flow, is employed to inversely derive the corresponding expression of foot vibration level under changes in weight of the equipment excited by the same level of base motion. The results show that the foot acceleration of the device gradually increases with the decrease of the device mass at the same transmitted vibration power flow to the base. Notably, under the condition of transmitting the same energy to the base, the foot vibration level generated by the new equipment surpasses the foot vibration level index of the old equipment. This study furnishes theoretical guidance for evaluating vibration transmission of the latest developed auxiliary machinery on board from an energy perspective, which can be employed in the engineering design of ships.
Hydrodynamics of Off-Bottom Plug Placements in Deviated Wells
Authors: Ghazal Abdallah , Shakeri Amin , Karimfazli Ida
Published: August 2024

Wellbores come in various shapes, from vertical to deviated and horizontal configurations. Deviated or horizontal wells typically involve a vertical drilling phase before shifting towards the target direction. As oil and gas production becomes economically unviable, well abandonment is common, involving the deployment of multiple cement plugs. The off-bottom plugs, located above the lowermost plug, are strategically placed in the vertical or least deviated sections of the well.

We consider a representative 2D model for the early stages of cement placement, where slurry is injected from a concentric injector with the well, and explore the influence of well inclination on the placement process. In vertical wells, the injected fluid forms a central finger below the injector. However, in highly deviated wells, the fluid slumps towards one side of the casing walls. The transition between these two flow regimes occurs through a monotonic change with the inclination angle. In all cases, the buoyancy-driven flow is disrupted, resulting in a mixed layer below the injector, and the accumulation of the injected fluid above it. While the accumulated fluid remains primarily unmixed with wellbore fluids in vertical wells, intermittent mixing occurs in deviated wells. The frequency and magnitude of this mixing change non-monotonically with the inclination angle.
Effects of Wave Nonlinearity on Solute Migration in Deformable Sediments
Authors: Zhao Hongyi , Liu Xiaoli , Jeng Dong-Sheng
Published: August 2024

This study employs a two-dimensional numerical model, coupling Biot’s poro-elastic theory with advection-dispersion equations, to examine the impact of wave nonlinearity on solute transport in deformable seabed sediment. The simulations reveal that compared to the second-order Stokes waves, the first-order cnoidal waves exhibit significant nonlinear effects, effectively enhancing the longitudinal dispersion coefficient and solute transport rate in marine sediment. However, this enhancement diminishes as wave height increases and water depth decreases, highlighting the diminishing impact of cnoidal wave nonlinearity under such conditions.
Experimental Investigation on Wave Evolution and Seabed Response During the Long-Term Development of Sloping Beach
Authors: Yang Yunhan , Wang Guangsheng , Xiao Ziwei , Sui Titi , Zhang Chi , Wang Gang
Published: August 2024

Nonlinear wave action plays a crucial role in cross-shore sediment transport, significantly impacting various coastal engineering challenges. This is especially true when assessing beach processes for shore protection methods, demanding precise evaluations. The nonlinearity of waves can instigate near-bed sediment transport. Previous studies mainly focused on the evolution of wave nonlinearity within specific cross-shore profiles, often neglecting the corresponding seabed response. To gain a deeper understanding of hydrodynamics on a sloping beach, we conducted experiments at a small scale within a flume. These experiments aimed to investigate wave evolution and seabed response concerning cross-shore profile development. Over a period of up to 60 hours, we continuously recorded wave heights and analyzed characteristic wave patterns. We also discussed the seabed response at various horizontal positions along the beach. Our findings reveal a reciprocal relationship between cross-shore profiles and wave evolution. In general, wave nonlinearity gradually increases during propagation. However, the nonlinear indicators of waves remain relatively stable over time at the same water depth. Meanwhile, wave-induced seabed responses vary both over time and across different spatial positions. The excess pore pressure within the seabed gradually decreases with increasing depth at various horizontal positions.
Coupled Analysis of an Remora-Inspired AUV Docking to a Submarine During Recovery Process
Authors: Xu Yunxin , Shi Weichao , Song Yang
Published: August 2024

To enhance the cost-effectiveness and safety of offshore operations, the utilization of autonomous underwater vehicles (AUVs) has become popular across various industries. However, traditional docking or recovery methods for AUVs can be inefficient, requiring the mother vehicle to remain stationary. Consequently, there is a critical need to develop underwater dynamic recovery systems for AUVs to reduce operation costs, shorten redeployment times, and enhance overall operational efficiency compared to traditional docking methods.

Recent investigations into the ‘hitchhiking’ behaviour of remoras, which have a symbiotic relationship with sharks, have revealed that the low-velocity region around the shark can significantly reduce drag on the remora during attachment. Drawing inspiration from this phenomenon, an AUV was developed. To further support the feasibility study of the underwater dynamic recovery system for AUVs, this paper utilized the commercial computational fluid dynamics (CFD) software, STAR-CCM+, to analyse the hydrodynamic characteristics of the AUV in close proximity to a self-propulsion submarine during the recovery process. This analysis considered changes in the AUV’s attitude, which is important as the AUV enters the boundary layer of the submarine and approaches it. The boundary layer flow, influencing the AUV’s resistance, also generates a force that attracts the AUV toward the submarine.

This research delves into the effects on the AUV when two underwater vehicles of significantly different sizes are in close proximity, analysing various stages during the recovery process. It lays the groundwork for further studies aimed at developing dynamic underwater docking operations.
Numerical Simulation of Forced Oscillation for Added Mass and Damping Characteristics of the SWACH Floating Wind Platform
Authors: Zhang Yali , Wang Hongchao , Santo Harrif , Larsen Espen , Lim Chin Lee
Published: August 2024

This study delves into the intricate realm of forced oscillation Computational Fluid Dynamics (CFD) simulations, placing a particular emphasis on evaluating the added mass and damping characteristics of the SWACH floating wind platform. Specifically designed by Sevan SSP and featuring damping skirts and a large moonpool, the SWACH platform represents a cutting-edge innovation in the field of floating wind energy.

These simulations spanned across distinct scenarios, representing various environmental conditions. The focal point of this extensive simulation effort is to meticulously investigate the influence of oscillation period and amplitude on critical parameters such as added mass and damping. These parameters play a pivotal role in understanding the dynamic behavior of the platform in response to wave forces, providing essential insights for the platform’s performance evaluation. Moreover, the study conducts a detailed component-level analysis, scrutinizing the inner skirts, outer skirts, and hull of the SWACH floater individually. This component-level investigation offers valuable insights into the functionality and interaction of each component, contributing to an understanding of the platform’s overall behavior. This comprehensive investigation is crucial for ensuring the platform’s optimal performance in offshore wind energy applications, offering significant potential for informed design and optimization of floating structures. By unraveling complex hydrodynamic phenomena through CFD simulations, this study provides a robust foundation for informed design decisions and the ongoing optimization of floating structures in the pursuit of sustainable offshore energy solutions.
Probabilistic Data Envelopment Analysis Applied to Risk-Based Inspection of Flexible Pipes
Authors: Ferraz Caroline , Netto Theodoro A. , Souza Marcelo Igor L. , Honorato Henrique , Vaillant Alyson G. , Custódio Anderson B. , Ferreira Lucas R. S. , Meirelles Eduardo V. , Moita Joao V.
Published: August 2024

Flexible pipelines and risers are widely used by oil and gas operators in Brazil in their subsea systems for offshore operations. These operators have teams of multidisciplinary specialists working on the integrity management of their assets, as well as a large amount of inspection data, a database of real failures, and failure predictive tools. However, inspection scope planning is based on the judgment of the experts operating the assets. With the advent of new technologies, the use of data science and decision-making tools has helped engineers to make more assertive and less subjective decisions. To ensure the operational safety of flexible pipes and risers, identifying the main failure modes that can lead to the total loss of structural integrity and all the failure mechanisms that will lead to each failure mode is essential. This work will present a risk-based inspection methodology for offshore flexible pipes and risers based on data envelopment analysis (DEA). The present methodology considers the organization of each failure mechanism through event trees, allowing the visualization of the chronological occurrence of non-conformities in stages until the failure mode is reached. Recent work has shown risk analyses using data envelopment analysis based only on events (nonconformities) detectable by inspection. The proposed methodology establishes a relative risk ranking for a group of flexible pipes based on event trees, formed by events detectable or not during inspection, considering their probability of occurrence over time.
Preliminary Evaluation of the Supply Chain Capability for Offshore Wind Farm Development in Tasmania
Authors: Chen Peggy Shu-Ling , Cahoon Stephen , Fan Hongjun , Cooper Mark , Haward Marcus
Published: August 2024

Australia has set an ambitious goal of attaining 82% of its electricity generation from renewable energy sources by 2030, with offshore wind energy expected to play a pivotal role in achieving this target. Australia has identified six priority offshore wind areas, with two officially announced, three in the proposal stage, and one under assessment. Establishing a reliable and resilient supply chain is paramount to developing Australia’s offshore wind farms. This paper focuses on offshore wind development in Tasmania, an island State of Australia. The purpose of the paper is to provide a preliminary evaluation of the offshore wind supply chain. Key variables integrated into the evaluation model encompass the offshore wind targets, the installed power capacity of individual turbines, international supply chain constraints, port capacity, vessel availability, and workforce considerations. This paper firstly assesses the demand for components of Tasmanian offshore wind projects based on the baseline and ambitious targets. Subsequently, it examines the corresponding demands and requirements for ports, vessels, and workforce. The paper also discusses the supply chain for Tasmanian offshore wind farm development and concludes with the opportunities and challenges for the future development of Tasmania’s offshore wind industry.
Dynamic Responses of Composite Sandwich Panels Under Air Blast Loading
Authors: Lu Yue , Liu Kun , Shi Shengzhao , Ke Li , Wang Zili
Published: August 2024

Sandwich plates have been widely used in shipbuilding industry due to its superior protective capability when subjected to extreme loads, and it has become an excellent candidate to replace conventional stiffened plates. This research investigates the blast response of composite sandwich panels with high density polyethylene (HDPE) core. Explosion tests are performed to reveal the primary failure characteristics of composite sandwich panels. Attention is focused on the effects of core arrangements. Meanwhile, numerical simulations are performed to examine the blast responses of sandwich panels. Coupled effects of strain rate and temperature are considered in the constitutive model. In combination with the validated numerical models, multiple failure patterns can be captured, including the perforations of front face, petalling or cracking of backface, plugging of filling core and debonding failure between cores and facesheets. Results indicate that introducing the HDPE core is beneficial to alleviating the damage extent of the sandwich panels. Under explosive loadings, composite sandwich panels with full-filling HDPE core possess more desirable anti-explosion capacity. Besides, more obvious debonding failure can be observed in sandwich panels when subjected to severe explosive loadings, and this phenomenon can be adequately captured in all numerical models with the developed material model.
An Operational Wind Wave Forecasting System for the South China Sea and Singapore Waters
Authors: Sasmal Kaushik , Oliveira Tiago , Xu Haihua , Chow Jeng Hei , Tkalich Pavel
Published: August 2024

Operational forecasts of wind waves are crucial for various practical applications in nearshore and offshore areas. Wave fields such as wave height, wave period and wave directions are used for the speed and voyage optimization of ships. High-resolution information of wind waves is often required for the planning of operations within the ports. Using a third-generation spectral wave model WAVEWATCH III®, we set up a high-resolution (∼250 m) wind wave forecast system in and around the South China Sea (SCS) with a focus on Singapore’s coastal waters. The SCS encounters extreme metocean conditions because of the impact of typhoons. These typhoons can generate extreme waves with a significant wave height (Hs) 10 m or higher in the SCS. Observations from satellite altimeters reveal extreme wave heights with 10 m Hs during the typhoon season. Therefore, prior information of such extreme sea states plays a central role in the safety of navigating ships, offshore platforms, and structures. The forecast system consists of two model domains. The large computation domain uses a rectangular grid, and it encompasses the Indian Ocean and includes the South China Sea. A high-resolution unstructured mesh is nested within the large domain. The model is driven by the 10 m winds from the Global Forecast System (GFS) provided by National Centers for Environmental Prediction (NCEP). The forecast run is updated daily. The significant wave height from the model is validated against satellite altimeter data and shows good agreement with the satellite data. Since in-situ wave observations are rarely available in the SCS and satellite altimeter tracks have limited coverage around Singapore waters, the wave forecast system based on the spectral wave model (WAVEWATCH III®) could be of great importance to Singapore’s coastal areas, offshore, and maritime sector.
CFD-Based Ship PMM Captive Tests Using OpenFOAM
Authors: Liu Jing , Zheng Yingying , Liu Daniel
Published: August 2024

This study presents a series of planar motion mechanism (PMM) captive tests conducted on a container ship model with a rudder using the numerical tool OpenFOAM. The flow solution is approximated by solving the Reyolds-averaged Navier-Stokes (RANS) equations, while the evolution of the free surface is captured using the volume of fluid (VOF) method. Predefined ship motions are simulated using a dynamic mesh technique. The numerical results of hydrodynamic forces and moment are compared with the published numerical data and model test results, demonstrating satisfactory agreement. However, discrepancies are observed in transverse forces in the dynamic PMM tests, prompting further exploration of flow characteristics. The present numerical method has demonstrated promising accuracy in predicting the hydrodynamics of the virtual PMM captive tests, suggesting its potential for developing simulator for ship maneuverability in future studies.
Ocean Wave Modelling for Indo-Pacific Region Under Extreme Weather Conditions Using the Third-Generation Wave Models
Authors: Xu Xingkun , Sasmal Kaushik , Xu Haihua , Tkalich Pavel
Published: August 2024

As the first recorded TC formation within 1.5 degrees of the equator, TC Vamei developed in the equatorial region on 27 December 2001 with diminishing Coriolis effect. Satellite-derived wave height exhibits high sea states during the passage of TC Vamei. In the present study, numerical experiments using the third-generation wave models, WAVEWATCH III® (WW3) and Simulating WAves Nearshore model (SWAN) were conducted on the sea states of the TC Vamei. The implementation of unstructured meshes produced simulation results that are consistent with the observed data. That is, when compared with ERS-2 satellite measurements, the root mean square error (RMSE) for WW3 and SWAN was only 0.36 m and 0.52 m, respectively. Additionally, in comparison with GFO satellite measurements, the RMSE was 0.37 m and 0.54 m for WW3 and SWAN. This is because the models exhibited different performance when simulating ocean waves with significant wave heights exceeding approximately 4–5 m. However, both numerical models demonstrated promising performances, while potential difference in air-sea momentum parameterization schemes adopted by WW3 and SWAN, in simulating extreme weather events.
The Effectiveness of Progressive Muscle-Relaxation Techniques in Improving Affective Well-Being Among Female Athletes During Menstruation: A Randomized Controlled Study
Authors: Abdelkefi Ichrak , Jarraya Sana
Published: August 2024

The aim of this study was to investigate the effect of progressive muscle relaxation on affective well-being (anxiety and mood), cognitive variables (sustained attention and reaction time), and aggressive behavior in female athletes during menstruation. Forty-five athletes age 18–22 years were randomly assigned to three groups: an experimental group (n = 15) undergoing eight sessions of 30-min progressive muscle relaxation, a breathing group (n = 15) engaging in eight sessions of 30-min deep breathing, and a control group (n = 15) receiving no intervention. The participants were evaluated during menstruation, at baseline, and after the intervention. Results showed significant improvements in mood () and anxiety () in the experimental group compared with the breathing group and the control group. No significant effects were found for aggressive behavior and cognitive variables. Progressive muscle-relaxation training is beneficial for improving mood and reducing anxiety in sportswomen during menstruation.
A CeO
2
(100) surface reconstruction unveiled by in situ STEM and particle swarm optimization techniques
Authors: Zhang Kai , Li Guanxing , Zou Chen , Chen Shiyuan , Li Songda , Han Zhong-Kang , Jiang Ying , Yuan Wentao , Yang Hangsheng , Ganduglia-Pirovano Maria Veronica , Wang Yong
Published: August 2024

The reconstruction of the polar CeO
2
(100) surface has been a subject of long-standing debates due to its complexity and the limited availability of experimental data. Herein, we successfully reveal a CeO
2
(100)–(4 × 6) surface reconstruction by combining in situ spherical aberration–corrected scanning transmission electron microscopy, density functional theory calculations, and a particle swarm optimization–based algorithm for structure searching. We have further elucidated the stabilizing mechanism of the reconstructed structure, which involves the splitting of the filled Ce(4f) states and the mixing of the lower-lying ones with the O(2p) orbitals, as evidenced by the projected density of states. We also reveal that the surface chemisorption properties toward water molecules, an important step in numerous heterogeneous catalytic reactions, are enhanced. These insights into the distinct properties of ceria surface pave the way for performance improvements of ceria in a wide range of applications.
Cyclin F–EXO1 axis controls cell cycle–dependent execution of double-strand break repair
Authors: Yang Hongbin , Fouad Shahd , Smith Paul , Bae Eun Young , Ji Yu , Lan Xinhui , Van Ess Ava , Buffa Francesca M. , Fischer Roman , Vendrell Iolanda , Kessler Benedikt M. , D’Angiolella Vincenzo
Published: August 2024

Ubiquitination is a crucial posttranslational modification required for the proper repair of DNA double-strand breaks (DSBs) induced by ionizing radiation (IR). DSBs are mainly repaired through homologous recombination (HR) when template DNA is present and nonhomologous end joining (NHEJ) in its absence. In addition, microhomology-mediated end joining (MMEJ) and single-strand annealing (SSA) provide backup DSBs repair pathways. However, the mechanisms controlling their use remain poorly understood. By using a high-resolution CRISPR screen of the ubiquitin system after IR, we systematically uncover genes required for cell survival and elucidate a critical role of the E3 ubiquitin ligase SCF
cyclin F
in cell cycle–dependent DSB repair. We show that SCF
cyclin F
–mediated EXO1 degradation prevents DNA end resection in mitosis, allowing MMEJ to take place. Moreover, we identify a conserved cyclin F recognition motif, distinct from the one used by other cyclins, with broad implications in cyclin specificity for cell cycle control.
DNA polymerase δ subunit Pol32 binds histone H3-H4 and couples nucleosome assembly with Okazaki fragment processing
Authors: Shi Guojun , Yang Chaoqi , Wu Jiale , Lei Yang , Hu Jiazhi , Feng Jianxun , Li Qing
Published: August 2024

During lagging strand chromatin replication, multiple Okazaki fragments (OFs) require processing and nucleosome assembly, but the mechanisms linking these processes remain unclear. Here, using transmission electron microscopy and rapid degradation of DNA ligase Cdc9, we observed flap structures accumulated on lagging strands, controlled by both Pol δ’s strand displacement activity and Fen1’s nuclease digestion. The distance between neighboring flap structures exhibits a regular pattern, indicative of matured OF length. While
fen1
Δ or enhanced strand displacement activities by polymerase δ (Pol δ;
pol3
exo−
) minimally affect inter-flap distance, mutants affecting replication-coupled nucleosome assembly, such as
cac1
Δ and
mcm2-3A
, do significantly alter it. Deletion of Pol32, a subunit of DNA Pol δ, significantly increases this distance. Mechanistically, Pol32 binds to histone H3-H4 and is critical for nucleosome assembly on the lagging strand. Together, we propose that Pol32 establishes a connection between nucleosome assembly and the processing of OFs on lagging strands.
The nonphototrophic hypocotyl 3 (NPH3) domain protein NRL5 is a trafficking-associated GTPase essential for drought resistance
Authors: Upadhyay-Tiwari Neha , Huang Xin-Jie , Lee Yi-Chen , Singh Shashi Kant , Hsu Chuan-Chi , Huang Shih-Shan , Verslues Paul E.
Published: August 2024

The mechanisms of plant drought resistance are unclear but may involve membrane trafficking and metabolic reprogramming, including proline accumulation. Forward genetic screening using a
proline dehydrogenase 1
(
ProDH1
)
promoter:reporter
identified a drought hypersensitive mutant with a single–amino acid substitution (P335L) in the nonphototrophic hypocotyl 3 (NPH3) domain of NPH3/root phototropism 2–like 5 (NRL5)/naked pins in Yucca 8 (NPY8). Further experiments found that NRL5 and other NPH3 domain proteins are guanosine triphosphatases (GTPases). NRL5, but not NRL5
P335L
, interacted with the RABE1c and RABH1b GTPases and the soluble
N
-ethylmaleimide–sensitive factor attachment protein receptors (SNAREs) Vesicle-Associated Membrane Protein (VAMP)721/722. These proteins controlled NRL5 localization and connection to trafficking while also being genetically downstream of, and potentially regulated by, NRL5. These data demonstrate that NRL5-mediated restraint of proline catabolism is required for drought resistance and also reveal unexpected functions of the NPH3 domain such that the role of NPH3 domain proteins in signaling, trafficking, and cellular polarity can be critically reevaluated.
Integrated single-cell RNA-seq analysis reveals mitochondrial calcium signaling as a modulator of endothelial-to-mesenchymal transition
Authors: Lebas Mathilde , Chinigò Giorgia , Courmont Evan , Bettaieb Louay , Machmouchi Amani , Goveia Jermaine , Beatovic Aleksandar , Van Kerckhove Job , Robil Cyril , Angulo Fabiola Silva , Vedelago Mauro , Errerd Alina , Treps Lucas , Gao Vance , Delgado De la Herrán Hilda C. , Mayeuf-Louchart Alicia , L’homme Laurent , Chamlali Mohamed , Dejos Camille , Gouyer Valérie , Garikipati Venkata Naga Srikanth , Tomar Dhanendra , Yin Hao , Fukui Hajime , Vinckier Stefan , Stolte Anneke , Conradi Lena-Christin , Infanti Fabrice , Lemonnier Loic , Zeisberg Elisabeth , Luo Yonglun , Lin Lin , Desseyn Jean-Luc , Pickering J. , Kishore Raj , Madesh Muniswamy , Dombrowicz David , Perocchi Fabiana , Staels Bart , Pla Alessandra Fiorio , Gkika Dimitra , Cantelmo Anna Rita
Published: August 2024

Endothelial cells (ECs) are highly plastic, capable of differentiating into various cell types. Endothelial-to-mesenchymal transition (EndMT) is crucial during embryonic development and contributes substantially to vascular dysfunction in many cardiovascular diseases (CVDs). While targeting EndMT holds therapeutic promise, understanding its mechanisms and modulating its pathways remain challenging. Using single-cell RNA sequencing on three in vitro EndMT models, we identified conserved gene signatures. We validated original regulators in vitro and in vivo during embryonic heart development and peripheral artery disease. EndMT induction led to global expression changes in all EC subtypes rather than in mesenchymal clusters. We identified mitochondrial calcium uptake as a key driver of EndMT; inhibiting mitochondrial calcium uniporter (MCU) prevented EndMT in vitro, and conditional
Mcu
deletion in ECs blocked mesenchymal activation in a hind limb ischemia model. Tissues from patients with critical limb ischemia with EndMT features exhibited significantly elevated endothelial MCU. These findings highlight MCU as a regulator of EndMT and a potential therapeutic target.
SARS-CoV-2 JN.1 variant evasion of IGHV3-53/3-66 B cell germlines
Authors: Paciello Ida , Maccari Giuseppe , Pierleoni Giulio , Perrone Federica , Realini Giulia , Troisi Marco , Anichini Gabriele , Cusi Maria Grazia , Rappuoli Rino , Andreano Emanuele
Published: August 2024

The severe acute respiratory syndrome coronavirus 2 variant JN.1 recently emerged as the dominant variant despite having only one amino acid change on the spike (S) protein receptor binding domain (RBD) compared with the ancestral BA.2.86, which never represented more than 5% of global variants. To define at the molecular level the JN.1 ability to spread globally, we interrogated a panel of 899 neutralizing human monoclonal antibodies. Our data show that the single leucine-455–to–serine mutation in the JN.1 spike protein RBD unleashed the global spread of JN.1, likely occurring by elimination of more than 70% of the neutralizing antibodies mediated by IGHV3-53/3-66 germlines. However, the resilience of class 3 antibodies with low neutralization potency but strong Fc functions may explain the absence of JN.1 severe disease.
Vaccines and monoclonal antibodies to prevent healthcare-associated bacterial infections
Authors: Sauvat Léo , Verhoeven Paul O. , Gagnaire Julie , Berthelot Philippe , Paul Stéphane , Botelho-Nevers Elisabeth , Gagneux-Brunon Amandine
Published: August 2024

Healthcare-associated infections (HAIs) represent a burden for public health with a high prevalence and high death rates associated with them. Pathogens with a high potential for antimicrobial resistance, such as ESKAPE pathogens (

E
nterococcus faecium,
S
taphylococcus aureus,
K
lebsiella pneumoniae,
A
cinetobacter baumannii,
P
seudomonas aeruginosa,

and

E
nterobacter species

) and
Clostridioides difficile
, are responsible for most HAIs. Despite the implementation of infection prevention and control intervention, globally, HAIs prevalence is stable and they are mainly due to endogenous pathogens. It is undeniable that complementary to infection prevention and control measures, prophylactic approaches by active or passive immunization are needed. Specific groups at-risk (elderly people, chronic condition as immunocompromised) and also healthcare workers are key targets. Medical procedures and specific interventions are known to be at risk of HAIs, in addition to hospital environmental exposure. Vaccines or monoclonal antibodies can be seen as attractive preventive approaches for HAIs. In this review, we present an overview of the vaccines and monoclonal antibodies in clinical development for prevention of the major bacterial HAIs pathogens. Based on the current state of knowledge, we look at the challenges and future perspectives to improve prevention by these means.
A novel system with robust compatibility and stability for detecting
Sugarcane yellow leaf virus
based on CRISPR-Cas12a
Authors: Wang Ting , Li Anzhen , Zhao Hong , Wu Qibin , Guo Jinlong , Tian Helei , Wang Jingwen , Que Youxiong , Xu Liping
Published: August 2024

Sugarcane yellow leaf virus
(SCYLV) can reduce sugarcane productivity. A novel detection system based on reverse transcription-multienzyme isothermal rapid amplification (RT-MIRA) combined with CRISPR-Cas12a, named RT-MIRA-CRISPR-Cas12a, was developed. This innovative approach employs crude leaf extract directly as the reaction template, streamlining the extraction process for simplicity and speed. Combining RT-MIRA and CRISPR-Cas12a in one reaction tube increases the ease of operation while reducing the risk of aerosol contamination. In addition, it exhibits sensitivity equivalent to qPCR, boasting a lower detection limit of 25 copies. Remarkably, the entire process, from sample extraction to reaction completion, requires only 52–57 minutes, just a thermostat water bath. The result can be observed and judged by the naked eye.

IMPORTANCE

Sugarcane yellow leaf disease (SCYLD) is an important viral disease that affects sugarcane yield. There is an urgent need for rapid, sensitive, and stable detection methods. The reverse transcription-multienzyme isothermal rapid amplification combined with CRISPR-Cas12a (RT-MIRA-CRISPR-Cas12a) method established in this study has good specificity and high sensitivity. In addition, the system showed good compatibility and stability with the crude leaf extract, as shown by the fact that the crude extract of the positive sample could still be stably detected after 1 week when placed at 4°C. RT-MIRA-CRISPR-Cas12a, reverse transcription polymerase chain reaction (RT-PCR), and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to detect SCYLV on 33 sugarcane leaf samples collected from the field, and it was found that the three methods reached consistent conclusions. This Cas12a-based detection method proves highly suitable for the rapid on-site detection of the SCYLV.
Electro-Optic Effect in Hexagonal Compounds RFeO3
Authors: Menshenin V. V. , Nosov A. P.
Published: August 2024

The linear electro-optic effect is investigated in films of RFeO3 compounds (R = Y, Lu, Yb) possessing hexagonal symmetry. A general equation for the optical indicatrix of the film at arbitrary orientation of an external electric field is derived. The equation of the indicatrix in the principal axes, as well as the principal refractive indices, are determined for the particular case of an external electric field orientation along the [010] axis. Two novel optical axes are identified in the presence of an electric field. It was determined that two isonormal modes propagate in the film when light propagates along the [100] direction. The refractive indices associated with these modes were also found. The phase shift associated with the propagation of these modes and caused by the presence of an electric field is calculated. The shift is linear along the electric field, thereby demonstrating the Pockels effect.
Recovery from acute haemorrhagic leucoencephalitis secondary to COVID-19
Authors: Bunting Nicholas , Martynoga Robert , Crayton Henry , Pandita Archana
Published: August 2024

A man in his 50s presented with sudden onset expressive aphasia and right-sided facial droop after experiencing coryzal symptoms and malaise for 7 days prior to admission. A brain MRI showed a rapidly progressive mass effect across both hemispheres and cerebrospinal fluid analysis revealed neutrophil predominance with raised protein levels. Acute disseminated encephalomyelitis was provisionally diagnosed, and high-dose methylprednisone was initiated.

On admission to the high dependency unit, the patient tested positive for COVID-19 and was treated with appropriate therapeutic agents for severe COVID-19. A subsequent brain biopsy confirmed a demyelinating process, strongly indicating a diagnosis of acute haemorrhagic leucoencephalitis when correlated with the presence of severe oedema on imaging. Nine sessions of plasma exchange were provided over 18 days.

At the time of writing, the patient has made an excellent recovery. We urge clinicians to consider this diagnosis and these treatment options for an otherwise devastating condition.
FGF23-secreting sinonasal tumour presenting with acute subdural haemorrhage and tumour-induced osteomalacia
Authors: Bhatia Sehajdev Singh , Malhotra Prabhjot Singh , Poole Kenneth , Malaviya Anshuman
Published: August 2024

A female in her 50s developed a headache, collapsed and was noted to have an acute atraumatic subdural haemorrhage (SDH) requiring surgical evacuation and intracranial pressure-directed therapy. Her background included recurrent epistaxis, severe generalised bone pain and multiple insufficiency fractures and an undifferentiated autoimmune connective tissue disease. Chronic hypophosphataemia, elevated alkaline phosphatase and raised fibroblast growth factor 23 (FGF23) were also noted. An MRI head and subsequent68Ga CT/positron emission tomography scan demonstrated an intensely avid tumour in the right ethmoid sinus, extending intracranially. Phosphate was aggressively replaced, and alfacalcidol was initiated to circumvent the effects of FGF23 on her kidneys and bone minerals. The tumour was biopsied and then definitively resected via combined endonasal and craniotomy approaches, resulting in good clinical improvement. FGF23 titre and serum phosphate both normalised leaving the diagnosis of a phosphaturic mesenchymal tumour-secreting FGF23, leading to tumour-induced osteomalacia.
Camptocormia in a young man with anti-GAD-seropositive stiff-person syndrome
Authors: Anusha Mekala , Ramesh Rithvik , Shanmugam Sundar , Hazeena Philo , Avadhani Deepa , Ranganathan Lakshmi Narasimhan , Paramanandam Vijayashankar , Kailash Kannan Karthik
Published: August 2024

Stiff-person syndrome (SPS) usually manifests as an autoimmune neuromuscular disorder characterised by pronounced and advancing rigidity, primarily affecting the trunk and proximal muscles. There are various clinical subtypes like classic SPS (truncal stiffness, generalised rigidity and muscle spasms), partial SPS (stiff-limb syndrome) and uncommon forms including progressive encephalomyelitis with rigidity and myoclonus. Camptocormia, defined as forward flexion of the spine in the upright position that disappears in the supine position, without fixed deformity, has been described only in two cases as an initial presentation of Anti glutamic acid decarboxylase (GAD) autoimmunity. We encountered a young male presenting with a progressive forward-leaning posture and involuntary rhythmic movements in the lower limb. Diagnostic workup included MRI, blood routines, autoimmune screening, genetic testing, lumbar puncture and electromyography. Elevated serum anti-GAD antibody levels, inflammatory CSF and certain other clinical features supported the diagnosis of SPS. Treatment involved benzodiazepines, muscle relaxants and immunotherapy with intravenous immunoglobulin. This case underscores the importance of considering immune-mediated causes, such as SPS, in patients presenting with camptocormia.