Article
Immunology
Alexandra L. L. Sacharok, Eric A. A. Porsch, Joseph W. St W. Geme III
Summary: Kingella kingae is an emerging pathogen causing osteoarticular infections in young children. Approximately 10% of young children are carriers of K. kingae in the oropharynx, and adherence to epithelial cells is the initial step for colonization.
INFECTION AND IMMUNITY
(2023)
Article
Physics, Multidisciplinary
O. J. Meacock, A. Doostmohammadi, K. R. Foster, J. M. Yeomans, W. M. Durham
Summary: The study demonstrates that slow movement of Pseudomonas aeruginosa is vital for its collective migration across surfaces, as it avoids being trapped by topological defects resulting from faster cell movements. In contrast, faster mutant cells are overtaken and outcompeted by slower wild-type cells at high cell densities, leading to faster collective behavior and migration. The physics of liquid crystals helps explain how bacteria can outcompete each other in the race for new territory by generating topological defects that trap fast-moving cells.
Article
Multidisciplinary Sciences
Marco J. Kuhn, Lorenzo Tala, Yuki F. Inclan, Ramiro Patino, Xavier Pierrat, Iscia Vos, Zainebe Al-Mayyah, Henriette Macmillan, Jose Negrete, Joanne N. Engel, Alexandre Persat
Summary: This study demonstrates that Pseudomonas aeruginosa actively directs twitching in the direction of mechanical input from type IV pili in a process called mechanotaxis. The Chp system controls the balance of forward and reverse twitching migration of single cells in response to mechanical signals. Collisions between twitching cells stimulate reversals, while Chp mutants either always or never reverse, leading to jamming and demonstrating the importance of mechanosensing in regulating group behavior.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Microbiology
Kalpana Subedi, Daniel Wall
Summary: Myxobacteria exhibit complex social behaviors that rely on coordinated cell movements on solid surfaces, known as social (S)-motility. This study characterized a new S-motility gene in Myxococcus xanthus and found that it interacts with a previously identified S-motility gene at high temperatures, contributing to the function of type IV pili. However, at low temperatures, this interaction is not necessary.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Microbiology
Amelia K. Schmidt, Alexa D. Fitzpatrick, Caleb M. Schwartzkopf, Dominick R. Faith, Laura K. Jennings, Alison Coluccio, Devin J. Hunt, Lia A. Michaels, Aviv Hargil, Qingquan Chen, Paul L. Bollyky, David W. Dorward, Jenny Wachter, Patricia A. Rosa, Karen L. Maxwell, Patrick R. Secor
Summary: The study reveals that the Pf phage protein PfsE inhibits the assembly of type IV pili, providing resistance to superinfection by phages that use type IV pili as a receptor. This finding has implications for the pathogenesis of P. aeruginosa.
Article
Microbiology
Amelia K. Schmidt, Alexa D. Fitzpatrick, Caleb M. Schwartzkopf, Dominick R. Faith, Laura K. Jennings, Alison Coluccio, Devin J. Hunt, Lia A. Michaels, Aviv Hargil, Qingquan Chen, Paul L. Bollyky, David W. Dorward, Jenny Wachter, Patricia A. Rosa, Karen L. Maxwell, Patrick R. Secor
Summary: Pseudomonas aeruginosa is often infected by Pf bacteriophages, which can lead to cell lysis during superinfection. The Pf protein PA0721, also known as PfsE, suppresses twitching motility in P. aeruginosa by binding to the T4P protein PilC, providing resistance to Pf infection and potentially modulating biofilm formation and virulence in the host bacteria.
Article
Biotechnology & Applied Microbiology
Yi-Ywan M. Chen, Hsing-Yi Wang, Chia-Hua Wu, Yu-Juan Lin, Cheng-Hsun Chiu
Summary: Although gene clusters encoding Tfp are commonly found in Streptococcus sanguinis, not all strains exhibit surface-dependent twitching motility. Tfp can serve as a ligand for host cell colonization, and Tfp retraction is essential for biofilm stability. The twitching phenotype is strain-specific and sensitive to growth media.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Marco J. Kuhn, Henriette Macmillan, Lorenzo Tala, Yuki Inclan, Ramiro Patino, Xavier Pierrat, Zainebe Al-Mayyah, Joanne N. Engel, Alexandre Persat
Summary: The opportunistic pathogen Pseudomonas aeruginosa adapts to solid surfaces to enhance virulence and infect its host. Type IV pili (T4P), long and thin filaments that power surface-specific twitching motility, allow single cells to sense surfaces and control their direction of movement. T4P distribution is polarized to the sensing pole by the chemotaxis-like Chp system via a local positive feedback loop.
Article
Multidisciplinary Sciences
Chao Li, Amanda Hurley, Wei Hu, Jay W. Warrick, Gabriel L. Lozano, Jose M. Ayuso, Wenxiao Pan, Jo Handelsman, David J. Beebe
Summary: This study describes a unique mode of collective movement by self-propelled, surface-associated spherical microcolonies with EPS cores in the gliding bacterium Flavobacterium johnsoniae, driven by an active process relying on the bacterial gliding apparatus. This mode of collective bacterial movement may have potential roles in biofilm dynamics, bacterial cargo transport, or microbial adaptation on solid surfaces.
NATURE COMMUNICATIONS
(2021)
Review
Microbiology
Zirou Ouyang, Hanlin Zhao, Min Zhao, Yaxuan Yang, Jianhong Zhao
Summary: Clostridioides difficile is a leading cause of antibiotic-associated diarrhea. Type IV pili (T4P) play a crucial role in C. difficile adherence and persistence in the host intestine. Recent studies have shown that T4P promote C. difficile aggregation, surface motility, and biofilm formation, enhancing its pathogenicity.
CRITICAL REVIEWS IN MICROBIOLOGY
(2023)
Article
Multidisciplinary Sciences
Thomas Harwood, Esthefani G. Zuniga, HoJun Kweon, Douglas D. Risser
Summary: Motility in prokaryotic organisms, such as cyanobacteria, is common and can be regulated by chemotaxis-like systems that sense light indirectly, possibly through alterations in proton motive force. This study demonstrates that cyanobacteria have a GAF-independent means of sensing light to regulate motility and provides insight into how a chemotaxis-like system regulates the T4P motors. The conservation of this system in cyanobacteria suggests it is a ubiquitous means of regulating motility in response to light.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Review
Biochemistry & Molecular Biology
Katarzyna Zegadlo, Monika Gieron, Paulina Zarnowiec, Katarzyna Durlik-Popinska, Beata Krecisz, Wieslaw Kaca, Grzegorz Czerwonka
Summary: Skin and wound infections are difficult to treat due to the diversity of bacteria and their motility plays a key role in causing infections. This article reviews the types of bacterial movement and discusses the underlying mechanisms that can be targeted for developing antibacterial therapies for wound infections. Five types of bacterial movement are identified: appendage-dependent (swimming, swarming, and twitching) and appendage-independent (gliding and sliding), all of which contribute to bacteria's ability to relocate and aid in infection.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Immunology
Christopher J. Alteri, Nora Rios-Sarabia, Miguel A. De la Cruz, Jorge A. Gonzalez-y-Merchand, Jorge Soria-Bustos, Carmen Maldonado-Bernal, Maria L. Cedillo, Jorge A. Yanez-Santos, Ygnacio Martinez-Laguna, Javier Torres, Richard L. Friedman, Jorge A. Giron, Miguel A. Ares
Summary: The study found that expression of tad/flp genes was significantly higher in the stationary phase compared to other growth phases, indicating that the bacteria do not require type IV pili during dormancy. Elevated gene expression levels were recorded when the bacteria were in contact with macrophages or epithelial cells for 4 hours compared to bacteria propagated alone. Antibody detection showed the presence of Flp pili on intra- and extracellular bacteria infecting eukaryotic cells.
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
(2022)
Article
Microbiology
Heather J. McDonald, HoJun Kweon, Shadi Kurnfuli, Douglas D. Risser
Summary: A DnaK-type chaperone system is identified to coordinate the activity of type IV pili (T4P) motors with the production of motility-associated polysaccharides in bacteria, providing a mechanism for the regulation of these processes.
Article
Microbiology
Anthony M. Martini, Bridget S. Moricz, Laurel J. Woods, Bradley D. Jones
Summary: Streptococcus sanguinis plays a crucial role in infective endocarditis, and the type IV pili produced by this pathogen are identified as important virulence factors. These pili affect the pathogen's ability to adhere to host cells, colonize the aortic endothelium, and form platelet-dependent biofilms. The research findings suggest that targeting type IV pili could be a potential strategy for the treatment of infective endocarditis caused by S. sanguinis.
MICROBIOLOGY SPECTRUM
(2021)
Article
Engineering, Biomedical
Shuangjun He, Jiani Yang, Xinxin Fan, Dong Lu, Shuang Zhang, Lei Yan
Summary: Bacterial magnetosomes have great potential in medicine and biotechnology. This study successfully obtained a high yield of magnetosomes using response surface methodology in an airlift bioreactor. The results confirmed the effectiveness of RSM in determining the optimal conditions for magnetosome formation.
JOURNAL OF BIOMATERIALS APPLICATIONS
(2023)
Article
Engineering, Civil
Hong-Wei Li, Zhao-Dong Xu, Daniel Gomez, Shirley J. J. Dyke, You-Wu Wang, Yi-Qing Ni
Summary: This paper presents numerical studies of the three-dimensional train-wheel-bridge-bearing (TWBB) system model. By coupling the subsystem models, the simulations show high computational efficiency. The results suggest a need to find a balance between the bridge and train seismic responses in future bearing design procedures for railway bridges.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2023)
Article
Engineering, Civil
Hong-Wei Li, Zhao-Dong Xu, Daniel Gomez, Shirley J. Dyke, Yi-Qing Ni, You-Wu Wang
Summary: This paper develops a numerical model of a three-dimensional train-wheel-bridge-bearing system for seismic analysis, filling the gaps in the investigation of bearing effects in dynamic analysis of train-bridge coupled system and the consideration of running train in existing studies on base isolation of railway bridges. The proposed TWBB model has fewer degrees of freedom than traditional finite element methods, is applicable to different types of bearings, and does not require iterations in the simulation, making it an efficient and flexible representation for engineering purposes.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
(2023)
Article
Mechanics
E. Deng, Huan Yue, Yi-Qing Ni, You-Wu Wang, Xu-Hui He, Zheng-Wei Chen
Summary: The study aims to determine the more suitable geometric turbulence generator, either the spire or the fence, for computational fluid dynamics (CFD) simulation of a fluctuating crosswind field in the tunnel-flat ground-tunnel (TFT) scene. The wind field characteristics in the TFT scene were analyzed based on field tests, and a CFD model was established using the mosaic mesh technology. The differences in wind field fluctuating characteristics under the two turbulence generator conditions were discussed using improved delayed detached eddy simulation (IDDES), showing that the turbulent crosswind generated by the spire is more consistent with the spectrum characteristics of the natural wind field.
Article
Engineering, Civil
Bei-Yang Zhang, Yi-Qing Ni
Summary: A data-driven optimal sensor placement strategy is proposed in this study, which aims at accurately reconstructing mode shapes for vibration-based structural damage detection by temporarily deploying a few vibration sensors on a target bridge. This strategy is also applicable for the upgrade of a long-term structural health monitoring system by using historical data collected from the current system.
ENGINEERING STRUCTURES
(2023)
Article
Construction & Building Technology
Jian-Fu Lin, Wei-Lin Wu, Jian-Liang Huang, Jun-Fang Wang, Wen-Xin Ren, Yi-Qing Ni, Li-Xin Wang
Summary: Structural damage detection is a challenging problem due to measurement noise and model error in structural health monitoring. In this study, an adaptive sparse regularization method is proposed to address this issue by considering spatially sparse damage as a prior constraint. The method combines an l(1)-regularized term and an adaptive regularization factor to formulate the damage detection problem.
STRUCTURAL CONTROL & HEALTH MONITORING
(2023)
Article
Engineering, Multidisciplinary
Qi-Ang Wang, Yang Dai, Zhan-Guo Ma, Jun-Fang Wang, Jian-Fu Lin, Yi-Qing Ni, Wei-Xin Ren, Jian Jiang, Xuan Yang, Jia-Ru Yan
Summary: Central to structural health monitoring is the modeling, manipulation, and interpretation of data using a sophisticated system. A novel application of a fully probabilistic and high-precision data modeling method, called improved Sparse Bayesian Learning, was proposed to address the challenge of accurately modeling and forecasting SHM measurements. The proposed method automates sparsity of the Bayesian model based on the features of SHM monitoring data, improving the generalization ability and data prediction accuracy. Embedded in a Bayesian framework with built-in protection against over-fitting, the proposed scheme exhibits high robustness to data noise, especially for data forecasting, and has been verified on real-world vibration data collected from a large-scale cable-stayed bridge.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Engineering, Multidisciplinary
Bei-Yang Zhang, Yi-Qing Ni
Summary: This paper proposes a novel adaptive modelling framework for sparse polynomial chaos expansion. It automatically determines the truncation degree and training sample set, and alleviates the curse of dimensionality issue in polynomial chaos expansion. The framework incorporates an adaptive basis selection strategy, a sequential sampling strategy and a sparse representation method to improve the precision and convergence rate of the model.
APPLIED MATHEMATICAL MODELLING
(2023)
Article
Engineering, Civil
Zheng-Wei Chen, Guang-Zhi Zeng, Yi-Qing Ni, Tang-Hong Liu, Ji-Qiang Niu, Hua-Dong Yao
Summary: This study investigates the reduction of aerodynamic drag in high-speed trains by proposing an air blowing configuration on the head and tail cars. The analysis of aerodynamic drag and slipstream velocity under different blowing velocities reveals that blowing speeds of Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut cause reductions in total drag coefficient (Cd) by 5.81%, 10.78%, 13.70%, and 15.43% compared to the without-blowing case. The blowing measure creates an air gap between the flow and train surface, resulting in a reduction of viscous and pressure drag. Considering blowing cost, efficiency, and flow structure evolution, a blowing speed of Ub = 0.10Ut is recommended. This speed leads to reduction ratios of 9.18%, 12.77%, 10.90%, and 10.78% for the head, middle, tail car, and total train's aerodynamic drag, respectively.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Engineering, Multidisciplinary
Yun-Ke Luo, Li-Zhong Song, Chao Zhang, Yi-Qing Ni
Summary: This research evaluates the efficiency of different noise mitigation measures on an elevated railway through in-situ measurements. Experimental results show that the rubber floating slab track can mitigate bridge-borne noise by 0-4 dB SPL, while the track acoustic absorber and track-side noise barrier combination can boost the insertion losses of SPL by 2-7 dB(A). The combined control strategy demonstrates better performance within the efficient noise reduction regions. The findings of this study can provide guidance for the design of noise control strategies for elevated railways.
Article
Mechanics
Jian Wang, Xin-Yuan Liu, E. Deng, Yi-Qing Ni, Pak-Wai Chan, Wei-Chao Yang, Yan-Ke Tan
Summary: This paper compares the results of wind tunnel tests and numerical simulations to determine the formation mechanism of the acceleration effect in gorge terrains under crosswinds. The results show that the most dramatic acceleration reaches 1.28-1.4 times the incoming wind speed when the mountain spacing is zero. The paper also discusses the effect of Reynolds number on the results and provides a reference for the design of windproof facilities in gorge terrains.
Article
Construction & Building Technology
Zheng-Wei Chen, Zhan-Hao Guo, Yi-Qing Ni, Tang-Hong Liu, Jie Zhang
Summary: This study investigates the effectiveness of suction to mitigate pressure waves generated in a tunnel when a high-speed maglev train travels through. The results show that suction can significantly reduce the amplitude of pressure changes and micro-pressure waves. Different suction velocities have different impacts on the tunnel aerodynamic effect.
SUSTAINABLE CITIES AND SOCIETY
(2023)
Article
Engineering, Mechanical
Ziquan Yan, Xiangyun Deng, Yi-Qing Ni, Linlin Sun
Summary: This study proposes an explicit finite element method to investigate the elastic layer effects in wheel-rail rolling contact. The method is validated by comparing it with Kalker's boundary element method. The results show that a harder layer introduces larger contact pressure, surface shear stress, and subsurface stress.
Review
Biochemistry & Molecular Biology
Yanan Sheng, Jiani Yang, Changyuan Wang, Xindi Sun, Lei Yan
Summary: This article provides a comprehensive summary and analysis of Nattokinase (NK), including its physical-chemical properties and producers. The synthesis of NK is summarized, but lacks specific details. The purification of NK poses challenges, such as complicated operation and low recovery rate. Combining multiple simple and efficient precipitation methods and purification materials may overcome these challenges. The article also discusses the potential application of NK in biomedicine and suggests using multi-strain combination fermentation or food flavoring agents to improve the odor of fermented foods. Overall, the article proposes future directions for NK studies and provides suggestions for subsequent researchers.
Article
Automation & Control Systems
Feng Wang, Jiaqi Xia, Xiaoyuan Zhu, Xing Xu, Yi-Qing Ni
Summary: This article presents a real-time predictive energy management strategy with mode transition frequency constraints to improve the energy efficiency of plug-in hybrid electric vehicles. It ensures low mode transition frequency and high calculation efficiency.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
