Microarray Analysis of Gene Regulations and Potential Association with Acephate-Resistance and Fitness Cost in Lygus lineolaris

The tarnished plant bug has become increasingly resistant to organophosphates in recent years. To better understand acephate resistance mechanisms, biological, biochemical, and molecular experiments were systematically conducted with susceptible (LLS) and acephate-selected (LLR) strains. Selection of a field population with acephate significantly increased resistance ratio to 5.9-fold, coupled with a significant increase of esterase activities by 2-fold. Microarray analysis of 6,688 genes revealed 329 up- and 333 down-regulated (≥2-fold) genes in LLR. Six esterase, three P450, and one glutathione S-transferase genes were significantly up-regulated, and no such genes were down-regulated in LLR. All vitellogenin and eggshell protein genes were significantly down-regulated in LLR. Thirteen protease genes were significantly down-regulated and only 3 were up-regulated in LLR. More than twice the number of catalysis genes and more than 3.6-fold of metabolic genes were up-regulated, respectively, as compared to those down-regulated with the same molecular and biological functions. The large portion of metabolic or catalysis genes with significant up-regulations indicated a substantial increase of metabolic detoxification in LLR. Significant increase of acephate resistance, increases of esterase activities and gene expressions, and variable esterase sequences between LLS and LLR consistently demonstrated a major esterase-mediated resistance in LLR, which was functionally provable by abolishing the resistance with esterase inhibitors. In addition, significant elevation of P450 gene expression and reduced susceptibility to imidacloprid in LLR indicated a concurrent resistance risk that may impact other classes of insecticides. This study demonstrated the first association of down-regulation of reproductive- and digestive-related genes with resistance to conventional insecticides, suggesting potential fitness costs associated with resistance development. This study shed new light on the understanding of the molecular basis of insecticide resistance, and the information is highly valuable for development of chemical control guidelines and tactics to minimize resistance and cross-resistance risks

Micromechanics Modeling of Transverse Tensile Strength for Unidirectional CFRP Composite

Transverse tensile strength of unidirectional (UD) composites plays a key role in overall failure of fiber-reinforced composites. To predict this strength by micromechanics, calculation of actual stress in constituent matrix is essentially required. However, traditional micromechanics models can only give the volume-averaged homogenized stress rather than an actual one for a matrix, which in practice will cause large errors. In this paper, considering the effect of stress concentration on a matrix, a novel micromechanics method was proposed to give an accurate calculation of the actual stress in the matrix for UD composite under transverse tension. A stress concentration factor for a matrix in transverse tensile direction is defined, using line-averaged pointwise stress (obtained from concentric cylinder assemblage model) divided by the homogenized quantity (obtained from a bridging model). The actual stress in matrix is then determined using applied external stress multiplied by the factor. Experimental validation on six UD carbon fiber-reinforced polymer (CFRP) specimens indicates that the predicted transverse tensile strength by the proposed method presents a minor deviation with an averaged relative error of 5.45% and thus is reasonable, contrary to the traditional method with an averaged relative error of 207.27%. Furthermore, the morphology of fracture section of the specimens was studied by scanning electron microscopy (SEM). It was observed that different scaled cracks appeared within the matrix, indicating that failure of a UD composite under transverse tension is mainly governed by matrix failure. Based on the proposed approach, the transverse tensile strength of a UD composite can be accurately predicted

Micromechanics Modeling of Transverse Tensile Strength for Unidirectional CFRP Composite

Transverse tensile strength of unidirectional (UD) composites plays a key role in overall failure of fiber-reinforced composites. To predict this strength by micromechanics, calculation of actual stress in constituent matrix is essentially required. However, traditional micromechanics models can only give the volume-averaged homogenized stress rather than an actual one for a matrix, which in practice will cause large errors. In this paper, considering the effect of stress concentration on a matrix, a novel micromechanics method was proposed to give an accurate calculation of the actual stress in the matrix for UD composite under transverse tension. A stress concentration factor for a matrix in transverse tensile direction is defined, using line-averaged pointwise stress (obtained from concentric cylinder assemblage model) divided by the homogenized quantity (obtained from a bridging model). The actual stress in matrix is then determined using applied external stress multiplied by the factor. Experimental validation on six UD carbon fiber-reinforced polymer (CFRP) specimens indicates that the predicted transverse tensile strength by the proposed method presents a minor deviation with an averaged relative error of 5.45% and thus is reasonable, contrary to the traditional method with an averaged relative error of 207.27%. Furthermore, the morphology of fracture section of the specimens was studied by scanning electron microscopy (SEM). It was observed that different scaled cracks appeared within the matrix, indicating that failure of a UD composite under transverse tension is mainly governed by matrix failure. Based on the proposed approach, the transverse tensile strength of a UD composite can be accurately predicted

AHR Regulates Metabolic Reprogramming to Promote SIRT1-Dependent Keratinocyte Differentiation

Activation of the transcription factor, AHR, in normal human epidermal keratinocytes increased AHR binding in the gene regions of the glucose transporter, SLC2A1, and the glycolytic enzyme, ENO1. This increased chromatin binding corresponded with AHR-dependent decreases in levels of SLC2A1 and ENO1 mRNA, protein, and activities. Studies of the ENO1 promoter showed activation of the AHR decreases the transcription of ENO1. Glycolysis was lowered by activation of the AHR as measured by decreases in glucose uptake and the production of pyruvate and lactate. Levels of ATP were also decreased. Downregulation of glucose metabolism, either by activation of the AHR, inhibition of glycolysis, inhibition of glucose transport, or inhibition of enolase, increased SIRT1 protein levels in normal human epidermal keratinocytes and the immortalized keratinocyte cell line, N/TERT-1. This increase in SIRT1 was abrogated by the addition of exogenous pyruvate. Moreover, keratinocyte differentiation in response to downregulation of glycolysis, either by activation of the AHR, inhibition of glucose transport, or inhibition of enolase, was dependent on SIRT1. These results indicate that regulation of glycolysis controls keratinocyte differentiation, and that activation of the AHR, by lowering the expression of SLC2A1 and ENO1, can determine this fate

Micromechanics Modeling of Transverse Tensile Strength for Unidirectional CFRP Composite

Transverse tensile strength of unidirectional (UD) composites plays a key role in overall failure of fiber-reinforced composites. To predict this strength by micromechanics, calculation of actual stress in constituent matrix is essentially required. However, traditional micromechanics models can only give the volume-averaged homogenized stress rather than an actual one for a matrix, which in practice will cause large errors. In this paper, considering the effect of stress concentration on a matrix, a novel micromechanics method was proposed to give an accurate calculation of the actual stress in the matrix for UD composite under transverse tension. A stress concentration factor for a matrix in transverse tensile direction is defined, using line-averaged pointwise stress (obtained from concentric cylinder assemblage model) divided by the homogenized quantity (obtained from a bridging model). The actual stress in matrix is then determined using applied external stress multiplied by the factor. Experimental validation on six UD carbon fiber-reinforced polymer (CFRP) specimens indicates that the predicted transverse tensile strength by the proposed method presents a minor deviation with an averaged relative error of 5.45% and thus is reasonable, contrary to the traditional method with an averaged relative error of 207.27%. Furthermore, the morphology of fracture section of the specimens was studied by scanning electron microscopy (SEM). It was observed that different scaled cracks appeared within the matrix, indicating that failure of a UD composite under transverse tension is mainly governed by matrix failure. Based on the proposed approach, the transverse tensile strength of a UD composite can be accurately predicted

Characterization of Residual Stresses and Grain Structure in Hot Forging of GH4169

Residual stresses (RS) in hot forging severely degrade the machining accuracy and stability of super alloy parts. This is the main reason for deformation during subsequent mechanical machining. RS need recognition, as well as the microstructure and properties achieved by forging. In this study, a simulation and experimental research on the single-pass compression of GH4169 are presented. RS variations with forging temperature, loading speed, and cooling speed are established by finite element (FE) simulation. Based on the FE results, an experiment is conducted at a temperature of 1020 ℃, loading speed of 25 mm/s, and press amount of 16 mm, immediately followed by water cooling. A new layer-stripping method is put forward for the high-efficiency measurement and correction of interior RS. Compared with the traditional strain gauge layer-stripping method, the measurement efficiency of the new layer-stripping method is increased by 10 times. Meanwhile, grain photographs are collected and grain size evolution is summarized; thus, the RS is characterized and evaluated from the angle of grains. It is demonstrated that the RS level rises with the increase in forging temperature, loading speed, and cooling speed, while the cooling method influences both the stress value and distribution. Compressive RS changes to tensile, while the average grain size reduces from the surfaces to the center. In the compressive regions, stress values share the same rules as grain size, while, in the tensile regions, they are contrary. The RS levels are divided according to the grain degree standard. According to the residual stress and grain distribution law of the blank, the optimal position of the part in the blank can be determined. Compared with the center position of the part in the blank, the residual stress of the part is reduced by 70%. The results provide useful strategies for the better design of forging technology, qualification examinations, and subsequent mechanical machining

Thin polymer electrolyte with MXene functional layer for uniform Li+ deposition in all-solid-state lithium battery

Solid polymer electrolyte (SPE) shows great potential for all-solid-state batteries because of the inherent safety and flexibility; however, the unfavourable Li+ deposition and large thickness hamper its development and application. Herein, a laminar MXene functional layer‒thin SPE layer‒cathode integration (MXene-PEO-LFP) is designed and fabricated. The MXene functional layer formed by stacking rigid MXene nanosheets imparts higher compressive strength relative to PEO electrolyte layer. And the abundant negatively-charged groups on MXene functional layer effectively repel anions and attract cations to adjust the charge distribution behavior at electrolyte–anode interface. Furthermore, the functional layer with rich lithiophilic groups and outstanding electronic conductivity results in low Li nucleation overpotential and nucleation energy barrier. In consequence, the cell assembled with MXene-PEO-LFP, where the PEO electrolyte layer is only 12 μm, much thinner than most solid electrolytes, exhibits uniform, dendrite-free Li+ deposition and excellent cycling stability. High capacity (142.8 mAh g−1), stable operation of 140 cycles (capacity decay per cycle, 0.065%), and low polarization potential (0.5 C) are obtained in this Li|MXene-PEO-LFP cell, which is superior to most PEO-based electrolytes under identical condition. This integrated design may provide a strategy for the large-scale application of thin polymer electrolytes in all-solid-state battery

Predicted amino acid sequence of two new esterases from LLS (LLSE1 and LLSE4) and LLR (LLRE1 and LLRE4) aligned with a previously reported esterase (AAT09370) from <i>L. lineolaris</i> using Clustal W method (gap penalty: 3.0, gap length penalty: 0.2) of DNAStar MegAlign (Ver. 8).

<p>GenBank accession: LLSE1: JQ964230; LLRE1: JQ964231; LLSE4: JQ964232; LLRE4: JQ964233. Three catalytic center residues (S²¹³, E³⁴², and H⁴⁶⁸) were boxed. Amino acid substitutions between LLS and LLR are marked with ♦; Amino acid substitutions between AAT09370 and LLE1 are marked with 0. Hyphens represent sequence alignment gaps. Identical residues among all esterases are shaded with black background.</p

Identification of 107 significantly up-regulated (≥2-fold) genes in LLR using microarrays and analyzed with ArrayStar and Blat2go protocol (www.blast2go.org).

<p>Identification of 107 significantly up-regulated (≥2-fold) genes in LLR using microarrays and analyzed with ArrayStar and Blat2go protocol (<a href="http://www.blast2go.org" target="_blank">www.blast2go.org</a>).</p