Cadherin specificity in adhesion and mechanotransduction

Cadherins mediate Ca2+ dependent cell-cell junction in all animal tissues. Tight regulation of cadherin adhesion plays critical roles in diverse biological processes. Differential binding between cadherin subtypes is widely believed to mediate cell sorting during embryogenesis. However, a fundamental unanswered question is whether cell sorting is dictated by the biophysical properties of cadherin bonds. Chapter 2 describes the atomic force microscope measurements of the strengths and dissociation rates of homophilic and heterophilic cadherin bonds. Measurements conducted with chicken N-cadherin, canine E-cadherin, and Xenopus C-cadherin demonstrated that all three cadherins cross-react and form multiple, intermolecular bonds. The mechanical and kinetic properties of the heterophilic bonds are similar to the homophilic interactions. The quantified bond parameters, together with previously reported adhesion energies were further compared with in vitro cell aggregation and sorting assays. Trends in quantified biophysical properties of the different cadherin bonds do not correlate with sorting outcomes. These results suggest that cell sorting in vivo and in vitro is not governed solely by biophysical differences between cadherin subtypes. Although the knowledge of molecular mechanism of cadherin adhesion is fundamental to understanding various processes in morphogenesis and the regulation of cell junctions, it remains largely unclear. In Chapter 3, single bond force measurement was used to directly address the functional roles of Trp2 and adhesive domains in C-cadherin interaction. The bond rupture forces between the cadherin ectodomains, domain deletion fragments, and Trp2 point mutant were measured and compared. The results, together with surface force measurements (Maruthamuthu, Ph.D thesis 2009) demonstrated that Trp2 residue both mediates the N-terminal interaction of cadherins and exerts an inter-domain allosteric effect on multiple domains far away from EC1. The findings of the allosteric coupling between classic cadherin ectodomains reconcile several previous models of cadherin adhesion and may have important implications for the regulation of cadherin-based cell adhesion. The importance of mechanical force to development, differentiation, and normal physiology is increasingly acknowledged. Although the classic cadherin complex is a good candidate for tension sensing in tissues, direct evidence for such a role is lacking. In Chapter 4, I examined the cell responses to both external applied forces and soft substrates via classic type I cadherins. Cells respond to applied force through cadherin bonds by reinforcing the bead-cell junction, showing cadherin complexes are force-sensors. Besides, depending on cell context, the cadherin mechanotransduction is subtype-specific. To study how cells respond to passive substrate rigidity, MCF-7 cell spreading on soft gels coated with E-cadherins was examined. The spreading area of cells increases with substrate rigidity. This behavior indicates that the cells are able to sense the substrate stiffness through cadherin receptors and modify their spreading accordingly. These results provide direct evidences that cadherins complexes are mechanosensors

Observation of whistler wave instability driven by temperature anisotropy of energetic electrons on EXL-50 spherical torus

Electromagnetic modes in the frequency range of 30-120MHz were observed in electron cyclotron wave (ECW) steady state plasmas on the ENN XuanLong-50 (EXL-50) spherical torus. These modes were found to have multiple bands of frequencies proportional to the Alfv\'en velocity. This indicates that the observed mode frequencies satisfy the dispersion relation of whistler waves. In addition, suppression of the whistler waves by the synergistic effect of Lower Hybrid Wave (LHW) and ECW was also observed. This suggests that the whistler waves were driven by temperature anisotropy of energetic electrons. These are the first such observations (not runaway discharge) made in magnetically confined toroidal plasmas and may have important implications for studying wave-particle interactions, RF wave current driver, and runaway electron control in future fusion devices

Vinculin potentiates E-cadherin mechanosensing and is recruited to actin-anchored sites within adherens junctions in a myosin II–dependent manner

Vinculin localizes to tension-bearing cell–cell junctions to help transmit signals from E-cadherin to the actin cytoskeleton in response to mechanical stress

Bibliometric and Visualization Analysis of the Literature on the Remote Sensing Inversion of Soil Salinization from 2000 to 2023

Tracing the historical development of soil salinization and monitoring its current status are crucial for understanding the driving forces behind it, proposing strategies to improve soil quality, and predicting future trends. To comprehensively understand the evolution of research on the remote sensing inversion of soil salinity, a scientific bibliometric analysis was conducted on research from the past two decades indexed in the core scientific databases. This article analyzes the field from various perspectives, including the number of publications, authors, research institutions and countries, research fields, study areas, and keywords, in order to reveal the current state-of-the-art and cutting-edge research in this domain. Special attention was given to topics such as machine learning, data assimilation methods, unmanned aerial vehicle (UAV) remote sensing technology, soil inversion under vegetation cover, salt ion inversion, and remote sensing model construction methods. The results indicate an overall increase in the volume of publications, with key authors such as Metternicht, Gi and Zhao, Gengxing, and major research institutions including the International Institute for Geoinformatics Science and Earth Observation and the Chinese Academy of Sciences making significant contributions. Notably, China and the USA have made substantial contributions to this field, with research areas extending from Inner Mongolia’s Hetao irrigation district to the Mediterranean region. Research in the remote sensing domain focuses on various methods, including hyperspectral imaging for salinized soil inversion, with an increasing emphasis on machine learning. This study enriches researchers’ knowledge of the current trends and future directions of remote sensing inversion of soil salinization

Improving photovoltaic properties via electric-field-induced orientation of conjugated polymer

A high electric field is applied to polarize the undoped MEH-PPV and the MEH-PPV:C-60 composite thin film in the process of spin-coating. Due to the polarization causing the orientation of the MEH-PPV chains, the resulting thin-film devices show improved photovoltaic properties. For undoped MEH-PPV devices, oriented under the electric field of 6 x 103 V cm(-1), the short-circuit current (J(sc)) and the external quantum efficiency (EQE) are enhanced by a factor of 2.5 and 2, respectively. For MEH-PPV-fullerene composite devices, oriented under the same field, the J(sc) and the EQE are improved by a factor of 1.8 and 1.7, respectively. (c) 2006 Elsevier Ltd. All rights reserved

Application and Research of Man-Machine Interface and Communication Technique of Mobile Information Acquisition Terminal in Facility Production

International audienceAs long as the deepen application of the Object Network Technology in the facility construction, a hot topics in research is coming out, that is how to achieve mobile operation through convenient and high-efficiency multiple resources utilization, in order to increase the proportion of the efficiency and output for the high tech facility in manufacture. The mobile collection terminals could display, transfer and collect the information from wireless sensor network high efficiency. This terminal will play an important role in the Object Network Technology application system, comparing to the others, it has such advantages of the good man-machine interaction (MMI) and reliable communication technology. We develop a mobile information collection terminal basic on the wireless sensor network, the information collection technology adopts the APC240 module to realize the wireless sensor data collection by the MODBUS Agreement; adopt wireless communication module to transfer the GPRS data; MMI realize the screen touch operation, also transplant the uC/OS+GUI making the operation more simply and understandably. This system is much convenience for more rural people to operate in daily work and with more application in agricultural construction in the future