Stability Analysis Of Structures Research Articles

Buckling responses and instability mode landscapes of composite sandwich panels with extreme auxeticity based on higher-order shear and normal deformation theory

Sandwich structures have been a subject of intense scrutiny and utilization in engineering applications. However, there has been a limited understanding of the mechanical behaviors of novel sandwich structures composed of auxetic metamaterials. This study aims to contribute to the body of knowledge by examining the buckling responses of sandwich beams or wide plates with an orthotropic anti-tetra chiral lattice (ATCL) aluminum cores and symmetric angle-ply carbon-fiber/epoxy face sheets, both of which can exhibit highly negative Poisson’s ratios or extreme auxeticity. The linear stability analysis of the sandwich structures under axial compression is conducted by applying the minimum potential energy principle and solving the eigenvalue problem using a numerical method. To achieve an accurate representation of arbitrary two-dimensional buckling morphologies, the first- and fifth-order shear and normal deformation models are employed to simulate the transverse kinematics of the face sheets and cores, while the finite-element model is utilized to discretize the longitudinal displacement of all constituents. The investigation reveals new insights into the interrelationship between global buckling, facial wrinkling, and shear crimping in conventional sandwich structures. The effects of material auxeticity on buckling responses are analyzed across an extensive range of geometrical configurations for the first time, unveiling five unprecedented buckling mode shapes, sophisticated buckling mode landscapes, and Poisson’s ratio-sensitive buckling criteria. These findings lay a crucial foundation for designing and optimizing auxetic sandwich structures, bringing diverse possibilities in lightweight constructions, acoustic insulation, energy absorption, and dynamic and shock mitigation.

Dynamic characteristics and structural stability analysis of a large annular tensegrity structure with radial ribs

PurposeIn order to make the aperture of spatial deployable antenna larger, this paper proposed the study on a spatial annular tensegrity structure with 100 m large scale, which could be one of the ideal solutions to improve the dimension of the antenna. This study is aiming to figure out the dynamic characteristic of ultra-large annular tensegrity and address the problem of insufficient rigidity with local modes that many ring truss-type deployable antenna structures have faced.Design/methodology/approachThis work is carried out based on the nonlinear dynamic modelling when fully considering the effect of bending and torsion deformation of beams, as well as the pretension of cables. Additionally, the structural stability analysis based on the proposed stability criterion is also presented to evaluate the tensegrity configuration with different distribution of cable groups.FindingsThis research results verify that the modified structure with radial ribs could eliminate the effect of the local vibration mode on stiffness and is suitable to meet the requirements of the annular tensegrity structure. Additionally, the calculation results demonstrate that the structural configuration of annular tensegrity with 36 groups of cables which share the nodes with radial ribs is more appropriate to enhance the stiffness and structural stability.Originality/valueA new large annular tensegrity structure with radial ribs and tensioned cables is proposed. Based on the proposed structural configuration, the positive definiteness of the tangent stiffness matrix is carried out as the criterion of stability and the composition of the analytical expression of the tangent stiffness matrix is analyzed. Four levels of tensegrity structure stability have been carried out and the influence of the structural parameters on the stability and the rigidity has been analyzed. A scaled-down prototype is developed to verify the feasibility of the design of the hoop-column-rib configuration by the deployment and dynamic experiment.

SNPeffect 5.0: large-scale structural phenotyping of protein coding variants extracted from next-generation sequencing data using AlphaFold models

BackgroundNext-generation sequencing technologies yield large numbers of genetic alterations, of which a subset are missense variants that alter an amino acid in the protein product. These variants can have a potentially destabilizing effect leading to an increased risk of misfolding and aggregation. Multiple software tools exist to predict the effect of single-nucleotide variants on proteins, however, a pipeline integrating these tools while starting from an NGS data output list of variants is lacking.ResultsThe previous version SNPeffect 4.0 (De Baets in Nucleic Acids Res 40(D1):D935–D939, 2011) provided an online database containing pre-calculated variant effects and low-throughput custom variant analysis. Here, we built an automated and parallelized pipeline that analyzes the impact of missense variants on the aggregation propensity and structural stability of proteins starting from the Variant Call Format as input. The pipeline incorporates the AlphaFold Protein Structure Database to achieve high coverage for structural stability analyses using the FoldX force field. The effect on aggregation-propensity is analyzed using the established predictors TANGO and WALTZ. The pipeline focuses solely on the human proteome and can be used to analyze proteome stability/damage in a given sample based on sequencing results.ConclusionWe provide a bioinformatics pipeline that allows structural phenotyping from sequencing data using established stability and aggregation predictors including FoldX, TANGO, and WALTZ; and structural proteome coverage provided by the AlphaFold database. The pipeline and installation guide are freely available for academic users on https://github.com/vibbits/snpeffect and requires a computer cluster.

Diterpenoid and C20 diterpenoid alkaloid as a potent inhibitor of SARS-CoV-2 main protease (Mpro): from Piper barberi Gamble, an endemic and endangered species of Southern Western Ghats

The present study investigated the phytochemicals and in silico anti-nCoV properties of Piper barberi, an endangered and endemic species of Southern Western Ghats. Using conventional soxhlet extraction method, the leaf and stem were extracted separately with methanol (PBLM and PBSM). The bioactive compounds from the extracts were identified using HR-LCMS/MS-qTOF analysis. These compounds were subjected to various in silico analyses to identify potential drug candidates against nCoV. The HR LCMS/MS analysis of PBLM and PBSM revealed the presence of phenols, flavonoids, alkaloids, and terpenoids in it and this is the first report of the phytoconstituents present in the species P. barberi. All the identified bioactive compounds were subjected to predict ADMET. Out of 49 identified compounds, only 31 passed drug-likeness properties and toxicity tests. Molecular interaction studies were conducted using the AutoDockTools 4.2.6., which showed that only 13 compounds exhibited acceptable binding affinity with the nCoV target Mpro. Structural stability and binding free energy analyses of the five compounds with the higher binding affinity indicated that the bioactive compounds Hetisine and Ajaconine are stable with both hydrogen bonds and hydrophobic interactions. Hetisine shows stable binding among these two compounds with two hydrogen bond interactions with the crucial catalytic dyad residue (His41). Thus, this study concludes that these compounds might potentially be used as an alternative drug candidate for managing nCoV. However, further experimental validation, including in vitro and in vivo assays, is required to substantiate the results. Communicated by Ramaswamy H. Sarma

Softening/Hardening Damage Model and Numerical Implementation of Seabed Silt-Steel Interface in Yellow River Underwater Delta

The interaction between soil and structure is a research hotspot in ocean engineering, and the shear performance of interfaces is an essential factor affecting the bearing capacity of offshore structures. Taking the Yellow River Underwater Delta as the research area, the Softening/Hardening damage model of the silt–steel interface and the determination method of model parameters are proposed based on the statistical damage theory. Through the interface monotonic shear test under the conditions of different normal stress, roughness and water content, the shear mechanical properties and volumetric deformation laws on the silt–steel interface are analyzed, and the damage model parameters are obtained. Finally, a FRIC subroutine for the damage model was developed based on ABAQUS. The research results indicate the following: (1) The interface between silt and steel exhibits two characteristics, softening/hardening and shear shrinkage/expansion, under different conditions. Roughness significantly impacts interfacial cohesion, while water content mainly affects the internal friction angle. (2) The softening model based on the classic rock damage model can better simulate the stress–strain relationship of the silt–steel interface under high normal stress and low water content. In contrast, the hardening model based on the classic hyperbola model can better simulate the stress–strain relationship under low normal stress and high water content. The calculated results of the softening/hardening model agree with the experimental results, and the model has 7 parameters. (3) The developed FRIC subroutine can effectively simulate the nonlinear mechanical behavior of the interface between silt and steel. The research results provide a reference for exploring the stability analysis of offshore structures considering interface weakening effects.

Analysis of Structure Stability of Underwater Shield Tunnel under Different Temperatures Based on Finite Element Method

The structural stability of the underwater shield tunnel during operations is affected by temperature variations. The effect of different structure temperatures on the underwater shield tunnel during the operation period was studied. By numerical simulation, the variation in the underwater shield tunnel temperature circle was analyzed. The variation patterns of the top arch, bottom arch, waist arch temperature, maximum principal stress, and settlement of the soil under different temperatures were obtained. The results showed that: (1) The early excavation time of the tunnel was short, and the temperature circle was small. The temperature circle expanded rapidly after 50 days of operating. The diffusion range increased from 1.5 m to 5.35 m: an increase of 256.7%. With the increase in time, the expansion rate of the temperature circle gradually slowed down. (2) The higher the temperature of the soil, the more complex the temperature transfer between the soil and the lining was while generating greater temperature stresses and reducing the safety of the tunnel. (3) When the tunnel was just excavated, the compression settlement of the top arch and the waist arch increased rapidly, reaching 5.43 mm and 0.24 mm, respectively. The bottom arch was squeezed by the soil on both sides, resulting in an uplift and rapid increase, reaching 4.94 mm. The settlement rate increased with the increase in the tunnel structure’s temperature. After the excavation, with the decrease in temperature, the strength of the soil and lining increased. The settlement of the top arch, bottom arch, and waist arch increased slowly with time, and the growth rate decreased gradually.

Analysis and characterization of structural, morphological, thermal properties and colloidal stability of CuO nanoparticles for various natural fuels

CuO nanoparticles were made quickly from natural macromolecules using the combustion process, and their structural, morphological, thermal, and particle stability properties were examined. All samples were monoclinic polycrystalline by XRD. Tea extract, wine, honey, and cow urine-assisted nanoparticles had crystallite sizes of 25.82, 26.18, 27.69, and 25.32 nm, respectively, according to the WH plot. FESEM and EDAX analysis verifies leaf, pollen grain, disc, and rice-like morphologies and stoichiometric products. Crystallite size correlates with TEM mean particle size. The parameters of the XRD pattern, which was matched with the standard data, reveal the presence of a pure monoclinic CuO phase with only substantial vibrations at 430 cm-1 to 603 cm-1. Thermal investigations (TG-DTA) demonstrate that particles are stable at 896°C-960°C before sublimating. Tea extract, wine, honey, and cow urine have been shown to affect CuO weight reduction. Anti-microbial study of the organic fueled CuO was made with Staphylococcus aureus (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) bacteria, also Candida albicans and Aspergillus niger fungi. It is found that CuO nanoparticles effectively inhibit fungal growth more than bacterial growth.

Numerical and experimental investigation on autoparametric resonance of multi-system structures

The analysis of dynamic stability in frame structures has always been a critical issue in engineering and mechanical design. Autoparametric resonance instability problems present a more complex dynamic instability mechanism than general parametric resonance, and determining the unstable regions of frame structures with multiple subsystems requires consideration of the coupled vibration of each subsystem. Unfortunately, existing approximate formulas are inadequate to analyze the stable boundary of autoparametric resonance in frame structures. To address this issue, this paper proposes a novel method called the dynamic axial force transfer coefficient (DTC) method to investigate the spatial dynamic instability characteristics of complex frame structures under parametric excitation due to autoparametric resonance. The proposed method, in conjunction with the harmonic balance method and the finite element method (FEM), established the global finite element equation of the frame and derived the stable boundary equation of autoparametric resonance for general frame structures. A complex spatial frame model is built to verify the effectiveness of the DTC method, and a comprehensive parametric analysis is conducted to investigate the dynamic instability mechanism of autoparametric resonance, including structural damping, static load coefficient, connection and boundary conditions of subsystems, and cross-sectional dimensions of subsystems. The results show that autoparametric resonance stability analysis of frame structures should consider the design parameters of each subsystem independently. In addition, strong coupling interaction between subsystems may induce autoparametric internal resonance of structure subjected to dynamic load. An autoparametric resonance test of a Γ-shaped frame is presented to further verify the proposed method. The test reveals the mechanism of the strong coupling effect, which may lead to a high risk of structural failure. More importantly, the DTC method can accurately determine the unstable boundary of multi-system frame structures, which is consistent with conventional methods (EGE) and experimental results, and predict the strong coupling effect of practical structures. The proposed method is simpler and more convenient than the existing methods for stability analysis of the autoparametric resonance of general frame structures, and can provide more effective guidance for structural design.

Structural characterization and stability of glycated bovine serum albumin-kaempferol nanocomplexes.

Kaempferol (Kae), a flavonoid is endowed with various functions. However, due to its poor water solubility and stability, its application in the food and pharmaceutical fields remains elusive. Emerging reports have emphasized the importance of bovine serum albumin (BSA), and glycosylated BSA (GBSA) prepared in the nature deep eutectic solvent system as drug delivery system carriers. In our study, ultraviolet and fluorescence spectra revealed the higher interactions of BSA and GBSA with Kae. Through analysis of Z-average diameter, zeta-potential, polydispersity index (PDI), encapsulation efficiency (EE), loading capacity (LC) of BSA-Kae nanocomplexes (NPs) and GBSA-Kae NPs, GBSA-Kae NPs showed a higher absolute value of zeta-potential and lower PDI, while its EE and LC were also higher. Structural characterization and stability analysis revealed that GBSA-Kae NPs had more stable properties. This study laid the theoretical foundation for improving the solubility and stability of Kae during its delivery and transport.

Synthesis and Characterization of Dicarboxylic Acid Esters of 1‐Hexadecanol for a Thermal Energy Storage Application Range of 50–55 °C

Dicarboxylic acid esters for thermal energy storage (TES) have attracted increasing attention in recent years because of their easy production, offering different temperatures, and providing solutions to the handicaps of fatty alcohols, which are potential TES materials. Dicarboxylic acid esters of 1‐hexadecanol are synthesized herein from adipic, succinic, and oxalic acid for the first time as TES materials. The dicarboxylic acid esters are characterized by Fourier transform infrared and proton nuclear magnetic resonance spectroscopy. Furthermore, the thermophysical properties of the dicarboxylic acid esters are examined by differential scanning calorimetry and thermogravimetric analysis methods. Additionally, the surface morphology features of the dicarboxylic acid esters are determined by polarized optical microscopy. The synthesized dicarboxylic acid esters of 1‐hexadecanol exhibit curiously specific behaviors that they melt at 49.2, 54.1, 54.8, and 53.5 °C, respectively, and crystallize at 47.7, 50.4, 53.1, and 50.2 °C, respectively. The applicability analyses of the dicarboxylic acid esters are carried out with integral graphs showing the sum of sensible and latent heat in a certain temperature range, time‐dependent heating and cooling graphs in a constant increasing temperature environment, and structural and thermal stability analyses after 1000 times heating–cooling thermal cycle.

Structural Stability and Surrounding Rock Integrity Analysis for Goaf-Side Entry with Small Coal Pillars in Longwall Mining

Goaf-side entry with small coal pillars (GESCPs) has an intrinsic advantage of improving the coal recovery ratio by implementing drifts with a small pillar size next to previous goafs. This technology is increasingly gaining popularity in the longwall mining of underground coal mines in China. This study focuses on understanding the critical condition of the main roof failure above the solid coal side of the goaf-side entry and investigating the key parameters that affect the structural stability of the surrounding rocks for GESCP. Mechanical models of the main roof and multi-layer cracking structures of the side wall of GESCP were established and the limiting equilibrium equation for the structural stability of the surrounding rock was proposed. The characteristics affecting the main parameters of the structural stability of the surrounding rock were analyzed. The research findings suggest that the integrity of the coal side walls plays a major role in maintaining the structural stability of the surrounding rock for GESCP under the given cross-sectional dimensions. Other factors, including the uniform load of overburden, the width of the coal pillar, the length of the roof hanging along the goaf side, and the fracture length in the main roof of the entry side wall, are less important. The key to achieving structural stability of the surrounding rocks for GESCP is to enhance the strength of the supporting coal side walls and, especially, to ensure the integrity of the small coal pillars. These conclusions were verified by engineering practice at the 1252(1) haulage gateway in a Coal Mine in China.

Bifurcations and Stability Analysis of Elastic Slender Structures Using Static Discrete Elastic Rods Method

Abstract Discrete elastic rods (DER) method provides a computationally efficient means of simulating the nonlinear dynamics of one-dimensional slender structures. However, this dynamic-based framework can only provide first-order stable equilibrium configuration when combined with the dynamic relaxation method, while the unstable equilibria and potential critical points (i.e., bifurcation and fold point) cannot be obtained, which are important for understanding the bifurcation and stability landscape of slender bodies. Our approach modifies the existing DER technique from dynamic simulation to a static framework and computes eigenvalues and eigenvectors of the tangential stiffness matrix after each load incremental step for bifurcation and stability analysis. This treatment can capture both stable and unstable equilibrium modes, critical points, and trace solution curves. Three representative types of structures—beams, strips, and gridshells—are used as demonstrations to show the effectiveness of the modified numerical framework, which provides a robust tool for unveiling the bifurcation and multistable behaviors of slender structures.

Investigation on nonlinear buckling performance of the optimized wing structure under the realistic flight cases

The nonlinear finite element simulation is a standard technique for structural stability analysis, whereas it still has disadvantages of highly computational cost and poor convergence, especially for the large and complex wing structure. In this paper, nonlinear buckling analysis of a wing structure is performed and focused on the local region that is prone to instability, the boundary conditions of which are determined using the sub-modeling technique and realistic flight conditions of an aircraft. Firstly, the flight envelope is calculated based on the preliminary parameters of a large aircraft. Three typically flight cases of the aircraft are selected and the corresponding aerodynamic loads are achieved. Then, an optimization problem with strength and deformation constraints is defined to minimize the weight of the wing structure under the design limit load. A significant reduction in structural weight is achieved by considering three typically flight cases in the optimization process. Next, linear structural analyses come to a conclusion that the upper skin of the wing butt box located between the inner and outer wings is easy to lose stability. The sub-modeling technique is used to extract the local model of the wing butt box from the global model of the wing structure. A nonlinear buckling analysis is performed on the local model by applying the realistic boundary conditions solved from the global model. The skin depressions produced by buckling are carefully studied. Finally, the wing upper skin is reinforced by assigning the stringers to increase the buckling resistance of the structure. The appearance of the skin depressions is significantly postponed, meanwhile the depth is largely reduced.

Use of RCC pile, anchor bolt and geogrid for building construction on the unstable slope

Rapid construction of buildings in urban area is creating lack of space available for new construction. This problem enforced to construct building on slope in hilly regions. However, the engineers and designers are concerned with the stability analysis of structures built on soil slopes, as it is difficult to achieve a uniform structural level on mountainous terrain. Also, it cannot be reduced to the same level of structural forms and part of base member may not be bound by an identical horizontal plane. The fundamental stability of the structure built on hill slope depends upon on its slope stability. Slope failure has been identified as one of the frequent devastating natural disasters that have claimed huge loss of property and lives. Therefore, in this research, “Phase 2 (2002)”, a Rocscience Finite Element (FE) program and “Slide”, a Rocscience limit equilibrium program were used to simulate and analyze a complex multi-staged model with RCC pile, Anchor Bolt and Geogrid for the stability analysis of slope. Bishop’s method was used to evaluate and analyze the factor of safety. Analysis of the two section (Section 1-1 and 2-2) of slope was taken into consideration for slope stability analysis. As per the analysis using the limit equilibrium approach, the factor of safety for existing slope at Section 1-1 and Section 1-1 was found to be 0.579 and 0.70 respectively. Moreover, it was found that the factor of safety of slope was increased significantly from 0.579 to 1.593 in Sections 1-1 and 0.70 to 1.319 in Section 2-2. In addition, the factor of safety of slope with strength reduction method is 1.408 and 1.05 for Sections 1 and 2 respectively after slope stabilization work in seismic condition. This shows that, the construction of buildings in slope terrain is possible, but it needs specialized excavation and slope protection work. RCC pile with anchor bolt and geogrid is one of the sustainable solutions for construction of structure in slope area.

The Generalized Mohr-Coulomb Failure Criterion

With the construction of supertall buildings such as high earth dams, the linear envelope of the Mohr-Coulomb (M-C) failure criterion fitted to lower confined pressure would significantly underestimate the loading capacity of foundations, causing a huge increase in the amount of earthwork. Given that the M-C criterion has dominated in the stability analysis of geotechnical structures, it is proposed in this study that the M-C criterion remain invariant in form but the cohesion c and the frictional factor f be related to the coefficient of intermediate principal stress b, called the Generalized Mohr-Coulomb (GMC) criterion. In other words, c and f are both functions of b, written as c(b) and f(b). In the simplest way, the GMC criterion for soils, a true three-dimensional failure criterion, can be established by using a piece of conventional triaxial apparatus. The GMC has a non-smooth strength surface like its conventional version. However, we prove from true triaxial tests and the characteristic theory of stress tensors that the failure surfaces in the stress space should be non-smooth per se for b = 0 or 1. Comparisons with other prominent failure criteria indicate that the GMC fits the test data best.

Montmorillonite as an Anti-Tuberculosis Rifampicin Drug Carrier: DFT and Experimental Study

A hybrid of montmorillonite (Mnt) and rifampicin (RIF) was synthesized and the structure and stability of the drug carrier system clarified. Density functional theory calculations involving dispersion corrections (DFT-D3) were performed to characterize interactions acting in the interlayer space of montmorillonite intercalated with rifampicin. The structure and stability of the RIF-Mnt intercalated complex were determined. Calculations revealed the deformation of the molecular structure of rifampicin after intercalation into the Mnt interlayer space due to the clay environment. The ansa chain of RIF was bent in the interlayer space compared with the structure of the RIF molecule in the monocrystal. RIF was keyed into the Mnt surface by means of numerous hydrogen bonds of weak to moderate strength. The calculated vibrational spectrum from ab initio molecular dynamics (AIMD) was in good agreement with the FTIR measured spectra and helped to analyze the overlapped vibrational bands. Based on analysis of structural stability, theoretical calculations revealed that Mnt is a suitable drug carrier for delayed release of the RIF drug. Batch adsorption experiments showed the large adsorption capacity of montmorillonite for RIF.

Static Strength and Buckling Analysis of an Aircraft Support

At the initial stage of design, the structural strength and stability of the load-bearing structural members of the aircraft are mainly considered. In this paper, the structural strength and stability of a support of aircraft assembly are analyzed. First, structural strength analysis, under the design load of 30.151 KN, and numerical analysis shows that, in the stress concentration area, the stress peak value is 571.9 Mpa. The experimental value of the strain sensor S6 position is compared with the numerical results, and the error is within 2.5%, which verifies the validity of the numerical model and the structural strength to meet the design requirements. Second, structural stability adopts the method of buckling analysis. Linear buckling analysis shows that the first six order buckling modes and critical loads. The first order critical load is 464.9 KN. Risk arc length method is used in the nonlinear buckling analysis. Considering the geometric imperfection of the support, 1% and 10% initial imperfection values are used. Nonlinear buckling critical load values—without imperfection and considering the initial imperfection—are obtained, which are 110.6 KN, 108.4 KN, and 106.2 KN, respectively. There is little difference between the three values, indicating that the geometric imperfection of the support is not obvious to the nonlinear buckling, and they have structural stability. In the case of no imperfection, the maximum deformation of the main area reaches 21.4 mm, and the support enters the instability state. This paper comprehensively discusses the results of structural strength and structural stability analysis, which can provide reference for the design and optimization of bearing components.

Structure-based virtual screening and molecular dynamics simulations for detecting novel candidates for allosteric inhibition of EGFRT790M

Structure-based virtual screening (SBVS) was applied to predict lead compounds for the allosteric inhibition of epidermal growth factor receptor (EGFR) by screening the library of chemical compounds prepared from the e-molecules chemical database. The library of chemical compounds consisting of 133,083 ligands was composed by evaluating the chemical and physical properties of e-molecules chemicals. The prepared library was screened by CCDC Gold software in the allosteric binding site of EGFRT790M using the library and virtual screening default parameters to filter out, respectively. The GOLD fitness scores 75 and 80 were selected as threshold values for the library and virtual screening processes, respectively. After the docking study, molecular dynamics simulations (MDS) of the top 25 compounds were built for calculating binding free energies from their MDS trajectories. MM-GBSA binding free energies for the compounds were computed from 20 ns MDS, 50 ns MDS and 200 ns MDS trajectories to filter out the candidates. Following MM-GBSA/MM-PBSA binding free energy calculations, six compounds were detected as the most promising candidates for allosteric inhibition of EGFRT790M. The dynamic behaviors of final compounds inside EGFR T790M were searched using structure stability, binding modes and energy decomposition analysis. Besides, the estimated inhibitors were exposed to docking study and MM-GBSA/MM-PBSA binding free energy calculations inside wild-type EGFR, respectively, to be determined their selectivity towards mutant form. Five of the estimated inhibitors displayed estimated selectivity towards EGFRT790M. Besides the ADMET properties of the estimated inhibitors were predicted by PreAdmet tools. Communicated by Ramaswamy H. Sarma

Computational analysis and molecular dynamics simulation of high-risk single nucleotide polymorphisms of the ADAM10 gene

Polymorphisms of the disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) are linked to pathophysiological changes in lung inflammation, cancer, Alzheimer’s disease (AD), encephalopathy, liver fibrosis, and cardiovascular diseases. In this study, we predicted the pathogenicity of ADAM10 non-synonymous single nucleotide polymorphisms (nsSNPs) in a wide array of mutation analyzing bioinformatics tools. We retrieved 423 nsSNPs from dbSNP-NCBI for the analysis, and 13 were predicted deleterious by each of the ten tools: SIFT, PROVEAN, CONDEL, PANTHER-PSEP, SNAP2, SuSPect, PolyPhen-2, Meta-SNP, Mutation Assessor and Predict-SNP. Further assessment of amino acid sequences, homology models, conservation profiles, and inter-atomic interactions identified C222G, G361E and C639Y as the most pathogenic mutations. We validated this prediction through structural stability analysis using DUET, I-Mutant Suite, SNPeffect and Dynamut. Molecular dynamics simulations and principal component analysis also indicated considerable instability of the C222G, G361E and C639Y variants. Therefore, these ADAM10 nsSNPs could be candidates for diagnostic genetic screening and therapeutic molecular targeting. Communicated by Ramaswamy H. Sarma

Density Functional Theory Study of Oxygen Evolution Reaction Mechanism on Rare Earth Sc-Doped Graphene

The development of a stable catalyst with excellent catalytic performance for the oxygen evolution reaction (OER) in alkaline environments is a key reaction in various electrochemical technologies. In this work, single-atom catalysts (SACs) systems in which scandium (Sc), a rare earth metal, with different N/C coordination environments (ScNxC3−x@SACs and ScNxC4−x@SACs of Sc) were systematically studied with the help of density functional theory (DFT) calculations. The results of the structural thermodynamic stability analysis indicated that the ScNxC3−x@SACs and ScNxC4−x@SACs systems are more stable with increasing N atom doping concentration around Sc. The ScN3, ScN3C, and ScN4 with better stability were selected as the objects of subsequent research. However, ScN3 and ScN4 form Sc(OH)2N3 and Sc(OH)2N4 structures with double-hydroxyl groups as ligands because of the strong adsorption of OH species, whereas the strong adsorption of OH species by ScN3C causes structural instability. Here, the overpotential (η) of Sc(OH)2N3 was 1.03 V; Sc(OH)2N4 had two reaction paths and the η of path 1 was 0.80 V, which was 0.30 V lower than that of path 2. Therefore, Sc(OH)2N4 can be used as a stable and promising OER catalyst with easy desorption of O2 and good cycle performance. The hydroxyl ligand modification of Sc-NxC3−x@SACs and Sc-NxC4−x@SACs provides a method for studying the catalytic performance of other rare earth elements.