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CRISPR-Cas immunity systems safeguard prokaryotic genomes by inhibiting the invasion of mobile genetic elements. Here, we screened prokaryotic genomic sequences and identified multiple natural transpositions of insertion sequences (ISs) into cas genes, thus inactivating CRISPR-Cas defenses. We then generated an IS-trapping system, using Escherichia coli strains with various ISs and an inducible cas nuclease, to monitor IS insertions into cas genes following the induction of double-strand DNA breakage as a physiological host stress. We identified multiple events mediated by different ISs, especially IS1 and IS10, displaying substantial relaxed target specificity. IS transposition into cas was maintained in the presence of DNA repair machinery, and transposition into other host defense systems was also detected. Our findings highlight the potential of ISs to counter CRISPR activity, thus increasing bacterial susceptibility to foreign DNA invasion. CRISPR-Cas immunity systems safeguard prokaryotic genomes by inhibiting the invasion of mobile genetic elements. Here, the authors show that insertion sequences can efficiently insert into cas genes, thus inactivating CRISPR defenses and increasing bacterial susceptibility to foreign DNA invasion. [ABSTRACT FROM AUTHOR]

Background: Thioredoxin reductase 1 (TrxR1) inhibitor, pyrano [3,2-a] phenazine, named CPUL-1, was synthesized with potential anticancer activity. The aim of the present work was to explore the potential anti-proliferative and anti-metastatic ability of CPUL-1 against A549 cancer cell lines in vitro. Methods and Results: First, Cell Counting Kit-8 (CCK8) assay was used to assess cell proliferation. The A549 cell migration was evaluated by wound healing assay and transwell assay. Second, the epithelial-mesenchymal transition (EMT)-related proteins in A549 cells treated with CPUL-1 were analyzed by western blot methods. Then, TrxR1 enzyme activity assay and reactive oxygen species (ROS) assay were conducted to evaluate the effect of CPUL-1 on TrxR1 inhibition and ROS levels. Finally, western blotting was used to explore the mechanism of CPUL-1. The study results revealed that the ability of cell proliferation and migration was decreased under CPUL-1 treatment. CPUL-1 could distinctly restrain the migration and invasion of A549 cells through inhibiting EMT process. The results of TrxR1 enzyme activity assay, ROS assay and western blotting showed that CPUL-1 influenced EMT via inducing ROS-mediated ERK/JNK signaling by inhibiting TrxR1 enzyme activity. Conclusions: Together, proliferation suppression and anti-metastasis activity of CPUL-1 in A549 cells were demonstrated by all the evidence. Our findings highlight the great potential of phenazine compound CPUL-1 to suppress A549 cells proliferation and metastasis. [ABSTRACT FROM AUTHOR]

Nano-textured surfaces (NTSs) can reduce adhesion and friction and thus have potential to increase the reliability of micro-electro-mechanical systems and nano-electro-mechanical systems. However, deformation of the nanotextures severely limits the effectiveness of using NTSs. This article presents a novel concept of nano-surface-engineering by texturing the surface with core-shell nanostructures to produce deformation-resistant nanotextures. The NTSs were produced by thermal evaporation of Al on Si substrates to form Al nanostructures and then depositing amorphous silicon on top of Al by plasma-enhanced chemical vapor deposition. Friction and deformation of the NTSs were studied using a TriboIndenter and a scanning electron microscope. The results show that the novel NTS significantly reduced the coefficients of friction of the surface without any detectable plastic deformations of the nanotextures even after heavy scratches. [ABSTRACT FROM AUTHOR]

Surface nano-patterning with Ni nanodot arrays was investigated for adhesion and friction reduction of contacting interfaces. Self-assembled anodized aluminum oxide (AAO) templates in conjunction with thermal evaporation was used to fabricate nano-patterned surfaces with ordered Ni nanodot arrays on Si substrates. Surface morphology of the Ni nanodot-patterned surfaces (NDPSs) was characterized by scanning electron microscopy (SEM). Adhesion and friction studies on a Ni NDPS and a baseline smooth Si(100) surface were conducted using a TriboIndenter employing a diamond tip with 100 μm nominal radius of curvature. The results show that the ordered Ni nanodot-patterning reduced the adhesion forces and coefficients of friction up to 92 and 83%, respectively, compared to those of the smooth silicon surface. Surprisingly, the nanoscale multi-asperity contact between the diamond tip and inhomogeneous Ni NDPSs under low loads follows a continuum contact mechanics model. [ABSTRACT FROM AUTHOR]

The electrical conductivity of soil is closely associated with various physical properties of the soil, and accurately establishing the interrelationship between them has long been a critical challenge limiting its widespread application. Traditional approaches in geotechnical engineering have relied on specific conduction mechanisms and simplifying assumptions to construct theoretical models for electrical conductivity. This paper adopts a different approach by using machine learning methods to predict the electrical conductivity of clay materials. A reliable dataset was generated using the quartet structure generation set to create random clay microstructures and calculate their electrical conductivity. Based on this dataset, machine learning methods such as least squares support vector machine and backpropagation neural networks outperform theoretical models in terms of prediction accuracy and resistance to interference, with a coefficient of determination (R2) exceeding 0.995 when unaffected by disturbances. The computation of Shapley values for input features aids in explicating the machine learning model. The results reveal that saturation is a key feature in predicting electrical conductivity, while porosity and constrained diameter are relatively less important. Finally, an already trained model is applied to the one-dimensional electroosmosis-surcharge preloading consolidation theory. The results of the calculations demonstrate that neglecting changes in soil electrical conductivity during electroosmosis can lead to an overestimation of the absolute values of anode excess pore water pressure and soil settlement. [ABSTRACT FROM AUTHOR]