Recently, it was revealed that tumor cells are significantly softer than normal cells. Although this phenomenon is well known, it is connected with many questions which are still unanswered. Among these questions are the molecular mechanisms which cause the change in stiffness and the correlation between cell mechanical properties and their metastatic potential. We studied mechanical properties of cells with different levels of cancer transformation. Transformed cells in three systems with different transformation types (monooncogenic N-RAS, viral and cells of tumor origin) were characterized according to their morphology, actin cytoskeleton and focal adhesion organization. Transformation led to reduction of cell spreading and thus decreasing the cell area, disorganization of actin cytoskeleton, lack of actin stress fibers and decline in the number and size of focal adhesions. These alterations manifested in a varying degree depending on type of transformation. Force spectroscopy by atomic force microscopy with spherical probes was carried out to measure the Young's modulus of cells. In all cases the Young's moduli were fitted well by log-normal distribution. All the transformed cell lines were found to be 40-80% softer than the corresponding normal ones. For the cell system with a low level of transformation the difference in stiffness was less pronounced than for the two other systems. This suggests that cell mechanical properties change upon transformation, and acquisition of invasive capabilities is accompanied by significant softening.
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http://dx.doi.org/10.1016/j.bbamcr.2014.01.032 | DOI Listing |
ACS Nano
January 2025
Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou 215123, P. R. China.
Knowledge of localized strain at the micrometer scale is essential for tailoring the electrical and mechanical properties of ongoing thinning of crystal silicon (c-Si) solar cells. Thinning c-Si wafers below 110 m are susceptible to cracking in manufacturing due to the nonuniform stress distribution at a micrometer region, necessitating a rigorous technique to reveal the localized stress distribution correlating with its device electrical output. In this context, a Raman microscopy integrated with a photovoltage mapping setup with high resolution to the submicrometer scale is developed to acquire correlative Raman-voltage of the localized physical properties at the microcracks on the rear side of c-Si solar cells.
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January 2025
Department of Psychology, Crean College of Health and Behavioral Sciences, Chapman University, Orange, California, United States of America.
Accumulating evidence indicates that unpredictable signals in early life represent a unique form of adverse childhood experiences (ACEs) associated with disrupted neurodevelopmental trajectories in children and adolescents. The Questionnaire of Unpredictability in Childhood (QUIC) was developed to assess early life unpredictability [1], encompassing social, emotional, and physical unpredictability in a child's environment, and has been validated in three independent cohorts. However, the importance of identifying ACEs in diverse populations, including non-English speaking groups, necessitates translation of the QUIC.
View Article and Find Full Text PDFPLoS One
January 2025
School of Resources and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, China.
The shear resistance of filling joints is an important factor affecting the stability of rock joints. Pressure-shear tests of cement-filled joints were carried out. Combined with the acoustic emission (AE) technique, the effects of normal stress, roughness and filling degree on the shear strength, damage morphology and damage evolution of cement-filled joints were investigated.
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January 2025
School of Civil Engineering, Guizhou University, Guiyang, Guizhou, China.
The mechanical properties of jointed rock bodies are important in guiding engineering design and construction. Using the particle flow software PFC2D, we conducted direct shear test simulations on joints with various inclinations and five different roughness levels to examine the models' crack extension penetration paths, damage modes, and strength characteristics. The findings indicate that the direction of the joint influences the pattern of the rock crack and its penetration route.
View Article and Find Full Text PDFPLoS One
January 2025
Faculty of Education and Arts, Sohar University, Sohar, Oman.
Conjugate Gradient (CG) methods are widely used for solving large-scale nonlinear systems of equations arising in various real-life applications due to their efficiency in employing vector operations. However, the global convergence analysis of CG methods remains a significant challenge. In response, this study proposes scaled versions of CG parameters based on the renowned Barzilai-Borwein approach for solving convex-constrained monotone nonlinear equations.
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