Root Mean Square Displacement Research Articles

Exploring the therapeutic mechanism of the Qing Palace Summer-avoiding Pearl based on network pharmacology and molecular dynamics simulation

Heatstroke is a thermal injury disease resulting from excessive water and electrolyte loss, as well as impaired heat dissipation, in hot and humid conditions. Modern medicine typically focuses on physical measures for early heatstroke intervention and prevention, with drug-related research being somewhat limited in scale and scope. In Chinese contexts, heatstroke is often referred to as “Zhongshu”, encompassing symptoms like nausea, vomiting, loss of appetite, emotional fluctuations and agitation, and headaches due to elevated body temperature. Traditional Chinese medicine boasts a long history and extensive literature on treating heatstroke. The Qing Palace Summer-avoiding Pearl, a treasured medicine used by ancient Chinese royalty for “Zhongshu” treatment and prevention, is of particular interest. This study aims to explore a new approach for early heatstroke prevention and intervention using the Qing Palace Summer-avoiding Pearl. We identified the disease types associated with this medicine through disease enrichment analysis and pinpointed the most likely therapeutic targets and effective substances via network pharmacology and molecular docking techniques. Furthermore, we conducted molecular thermodynamic analyses on six target Plant Extracts (PEs) using molecular dynamics simulations, examining parameters such as Root Mean Square Displacement (RMSD), Radius of gyration (Rg), and hydrogen bonds. The results indicated that the complexes exhibited favorable binding performance, which may facilitate further research on the Qing Palace Summer-avoiding Pearl.

Tower cranes mixed H2/H∞ under wind load research on active vibration control

The offshore platform tower crane is affected by sea breeze, which causes severe vibration, which causes damage to the crane structure and reduces the working efficiency and performance of the crane. Therefore, the vibration suppression under the complex environment of sea breeze has become a key problem to be solved in practical engineering. Firstly, a pulsating wind excitation model with wind speed changing at any time is established to simulate the time sequence of downwind and crosswise wind loads, which is used to reflect the actual wind speed fluctuations. Secondly, the pulsating wind model is applied to the crane finite element model, and the structural vibration characteristics are explored by analyzing the dynamics of the tower crane under wind excitation，the dynamic model of tower crane system under pulsating wind excitation is established, and the system state equation is constructed. Considering the vibration displacement performance of tower crane structure, a hybrid [Formula: see text] optimal performance vibration active control strategy is proposed. Finally, simulation experiments are carried out. The results show that, compared with the AA controller under the same conditions, the root mean square of displacement under downwind excitation decreases by 65.77%, 64.31% and 63.13%, respectively, and the root mean square of displacement under transverse wind excitation decreases by 62.8%, 65.51% and 62.6%, respectively. The results show that the proposed control method can effectively suppress tower crane vibration.

Self-Assembly of V-Shaped Polyaromatic Amphiphiles Studied by Molecular Dynamics Simulation.

V-shaped polyaromatic amphiphiles (VPAAs) form micelle-like nonbonded self-assemblies in aqueous solution and feature prominent properties of encapsulation and solubilization for various types of hydrophobic molecules. To understand microscopic molecular characteristics underlying the wide capability of solubilization, the atomic-level molecular structures of the self-assemblies of VPAAs were investigated by microsecond molecular dynamics (MD) simulations. The MD simulations showed that VPAAs spontaneously formed quasi-stable self-assemblies, in close agreement with experimental observations. To characterize the nanosized structures of the assemblies and their microscopic conformational changes, we developed a root-mean-square displacement (RMSD)-based structural similarity metric applicable to molecular assemblies. Through conformational classification by an unsupervised clustering, highly stable conformations depending on the number of constituent molecules in the assemblies were identified. The analysis revealed that the stable conformations of the VPAA assemblies flexibly reorganized depending on the number of constituent molecules, well explaining the wide capability of solubilization of hydrophobic molecules of various sizes and shapes.

Effects of turbulence intensity and integral length scale on wind-induced vibrations of a three-dimensional aeroelastic square cylinder

Despite a wealth of prior research on the effects of free-stream turbulence (FST) on the aerodynamics of square cylinders, there is limited knowledge about their aeroelasticity such as characteristics of wind-induced vibrations that vary with the FST properties. This paper focuses on the investigation of the effects of FST properties including longitudinal turbulence intensity and integral length scale on the wind-induced vibrations of a three-dimensional (3D) aeroelastic square cylinder with an aspect ratio of 10 (a super-tall building model). Through wind tunnel testing, displacements of the aeroelastic model are measured in smooth flow and four turbulent flows to experimentally investigate its characteristics of fluid-solid interaction, including along- and across-wind vibrations, especially vortex-induced vibration and galloping. The effects of the turbulence intensity with a higher-level than previous studies are also investigated. The results show that the root-mean-square (RMS) displacements of the along-wind responses increase with the increase of turbulence intensity and are not affected by integral length scale. For the across-wind responses, in the non-lock-in region, the RMS displacements generally increase with the increase of turbulence intensity. In the lock-in region, the RMS displacements remain unchanged with the increase of turbulence intensity, while increase with the increase of integral length scale. This paper aims to improve the comprehension of the effects of FST on the wind-induced vibrations of 3D square cylinders and to furnish valuable insights for the wind-resistant design of slender structures, such as supertall buildings.

Evaluation of inhibition effect and interaction mechanism of antiviral drugs on main protease of novel coronavirus: Molecular docking and molecular dynamics studies

The outbreak of pneumonia caused by the novel coronavirus (SARS-CoV-2) has presented a challenge to public health. The identification and development of effective antiviral drugs is essential. The main protease (3CLpro) plays an important role in the viral replication of SARS-CoV-2 and is considered to be an effective therapeutic target. In this study, according to the principle of drug repurposing, a variety of antiviral drugs commonly used were studied by molecular docking and molecular dynamics (MD) simulations to obtain potential inhibitors of main proteases. 24 antiviral drugs were docked with 5 potential action sites of 3CLpro, and the drugs with high binding strength were further simulated by MD and the molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) binding free energy calculations. The results showed that the drugs with high flexibility could bind to 3CLpro better than those with low flexibility. The interaction mechanism between antiviral drugs and main protease was analyzed in detail by calculating the root mean square displacement (RMSD), root mean square fluctuation (RMSF) and interaction residues properties. The results showed that the six drugs with high flexibility (Remdesivir, Simnotrelvir, Sofosbuvir, Ledipasvir, Indinavir and Raltegravir) had strong binding strength with 3CLpro, and the last four antiviral drugs can be used as potential candidates for main protease inhibitors.

Comparative Analysis of Dual-Task and Single- Task Balance Exercises in Improving Static Balance in Individuals with Anterior Cruciate Ligament Reconstruction

Introduction: Various balance exercises have been employed to enhance functional stability and balance in individuals who have undergone anterior cruciate ligament (ACL) reconstruction; however, no study has explored the use of dual-task balance exercises for these patients. This study compares the effects of dual motor task balance exercises and single-task exercises on the static balance indices of individuals with ACL reconstruction. Materials and Methods: In a single-blind randomized controlled trial, 27 subjects who had undergone ACL reconstruction were randomly divided into two groups: Dual-task and single- task balance exercises. Both groups performed their exercises three days a week for one month. Static balance indicators were assessed at the beginning and end of the treatment. Results: The results demonstrated that after the treatment, there was a statistically significant decrease in various center of pressure variables, including mean displacement in the anterior- posterior and medial-lateral directions, total path length, mean velocity of displacement, root mean square of displacement, and velocity. Furthermore, the knee injury and osteoarthritis outcome score significantly increased in both groups (P<0.05). However, when comparing the two groups, no significant difference was observed after the treatment (P>0.05). Conclusion: Dual-task and single-task motor exercises improve static stability and knee function levels in patients who have undergone ACL reconstruction. Meanwhile, the effectiveness of these exercise types does not significantly differ from each other.

Effects of turbulence integral length scales on aerodynamic characteristics and displacement responses of a square prism

This paper investigates the influence of the inflow turbulence integral length scales on the aerodynamic forces on a surface-mounted finite-length square prism and its displacement responses by computational fluid dynamics simulations. Four turbulent inflow conditions with the same mean wind speed and turbulence intensity but different longitudinal and transverse turbulence integral length scales are generated for the simulations. First, the wind pressures and forces on a rigid square prism model and the shear layer characteristics are simulated by large eddy simulations. The simulation results show that the mean characteristics of the wind pressures and shear layers are not sensitive to the turbulence integral length scales. However, the root mean square (RMS) wind pressures on side faces and RMS across-wind forces are increased with the longitudinal turbulence integral length scale, and the mechanism is analyzed by the proper orthogonal decomposition. Second, the displacement responses at the mean wind speed of vortex-induced resonance are computed based on an aeroelastic square prism model by fluid–solid interaction simulations. The RMS displacements of the model are observed to be more sensitive to the transverse turbulence integral length scale rather than the longitudinal turbulence integral length scale. Finally, the influence of the turbulence integral length scales on the Reynolds stresses around the square prism is presented and discussed.

Enhancing Zn (II) recovery efficiency: Bi-divalent nickel–cobalt ferrite spinel NiXCo1-xFe2O4 as a Game-changing Adsorbent—an experimental and computational study

This study presents a comprehensive investigation into NiXCo1-xFe2O4 (x = 0.5) spinel nanoparticles synthesized through a one-pot hydrothermal method using Co(NO3)2.6H2O and Ni(NO3)2.6H2O salts. XRD, FTIR, FESEM, and VSM analyses confirmed a cubic structure of NiXCo1-xFe2O4 (x = 0.5) nanoparticles without impurities. These nanoparticles exhibit efficient Zn (II) adsorption characteristics, following Langmuir isotherm and pseudo-second-order kinetics. The maximum adsorption capacity was measured to be 666.67 mg g−1 at pH = 7, with mechanisms involving both electrostatic attraction and cation exchange. Desorption studies indicate more than 75% Zn (II) recovery in an acidic environment (pH = 2) after three cycles. Computational analysis was used to validate the experimental results through Molecular Dynamics simulations, initially focusing on NiXCo1-xFe2O4 (x = 0.5). Further exploration involved variations in x at 0.25 and 0.75 to identify the optimal Ni and Co ratio in this bivalent cation spinel ferrite. Computational analyses reveal the superior performance of NiXCo1-xFe2O4 (x = 0.75) in Zn (II) removal, supported by radial distribution analysis, VdW energy, Coulombic energy, mean square displacement (MSD), root mean square displacement (RMSD), and interaction energy. This comprehensive study provides valuable insights into the adsorption behavior and structural stability of NiXCo1-xFe2O4 nanoparticles, showcasing potential applications in Zn (II) removal.

Unveiling reversible hydrogen storage mechanism for the 2D penta-SiCN material

The promise of using 2D materials for hydrogen storage has broad prospects, ascribe to their significant specific surface area and lightweight properties. In this work, the hydrogen storage capability and reversible storage mechanism of 2D penta-SiCN material are investigated based on the first-principles computational method. Thermal stability of penta-SiCN is calculated by the ab-initio molecular dynamics (AIMD) simulation and root-mean-square displacement (RMSD) algorithm. It has been found that penta-SiCN is thermodynamically stable even after adsorbing hydrogen molecules. Taking into account the benchmarks of average and continuous adsorption energies of the adsorption systems, a pristine 2 × 2 × 1 penta-SiCN substrate has the ability to adsorb up to 26H2 molecules, which results in a maximum hydrogen storage capacity of 10.80 wt%. According to the semi-empirical calculation method that based on the thermodynamic analysis, the penta-SiCN adsorption system has a high reversible hydrogen storage capacity of 9.57 wt% within the adsorption and desorption application working conditions. The results proposed in this study demonstrates that penta-SiCN exhibits considerable promise for hydrogen storage with its substantial hydrogen storage capacity, exceptional reversibility, and eco-friendly characteristics.

Optimization and comparative analysis of an AISD suspension system with inerter element for enhanced ride and handling

This paper presents a comprehensive study on the modeling and optimization of an advanced suspension system, known as the Air Springs Inerter-Spring-Damper (AISD) system, incorporating an inerter element. A linear quarter car model is utilized to analyze the vibrational behavior of the AISD system when subjected to harmonic road disturbances. The steady-state response of the system is investigated by deriving the root mean square (RMS) values of the absolute relative displacement and acceleration of the sprung mass. To optimize the quarter car model, a criterion based on minimizing the absolute acceleration RMS while considering the relative displacement RMS is employed to calculate the inerter coefficient. The performance of the AISD suspension system is compared to that of both conventional quarter car systems and traditional air quarter car systems, with a focus on ride comfort and handling. The results demonstrate that the proposed AISD system outperforms the other two suspension systems, exhibiting a significant improvement in ride quality. Specifically, the AISD system achieves a 45% enhancement over the air suspension and an 82% improvement over the classic suspension system.

Comparison of the Effects of Cognitive Dual-Task and Single-Task Balance Exercises on Static Balance among People with Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial.

The anterior cruciate ligament (ACL) reconstruction surgery improves mechanical stability; however, functional stability remains impaired. Balance exercises can help improve functional stability. The effect of cognitive dual-task balance exercises has not been studied in people with ACL reconstruction surgery; therefore, this study aimed to compare the effect of cognitive dual-task and single-task balance exercises on the static balance indices in these individuals. This study was a randomized clinical trial. After a period of conventional physiotherapy and applying inclusion criteria, 28 patients with ACL reconstruction surgery were randomly divided into two groups of cognitive dual-task and single-task balance exercises. Each group received the relevant exercises for four weeks, three times a week, with each session lasting 20 min. Center of pressure variables, including mean displacement in anterior-posterior and medial-lateral directions, total path length, mean velocity of displacement, root mean square of displacement and velocity, and the elliptical area, were measured using the FDM pressure platform before and after the interventions as the primary outcomes. Knee Injury and Osteoarthritis Outcome Score (KOOS) scale was completed by the participants before and after the interventions. The measured static balance variables and KOOS subscales had significant differences before and after intervention in both groups (P<0.05); however, no statistically significant difference was observed in these variables between the two groups. There was no significant correlation between KOOS subscales and measured static balance variables. Both cognitive dual-task and single-task balance exercises improved the indicators related to static balance and the level of functional disability of the knee. However, cognitive dual-task balance exercises had no superiority over single-task balance exercises in ACL-reconstructed individuals.

Thermal properties and mechanical behavior of functionalized carbon nanotube-filled polypropylene composites using molecular dynamics simulation

Polypropylene (PP) is widely recognized as an environmentally friendly material for cable insulation due to its good insulation performance and environmental friendliness. One common method for enhancing the overall performance of PP is the addition of nanoparticles. To analyze the influence of different functionalized multi-walled carbon nanotubes (MWCNT) fillers on the properties of PP/MWCNT composite materials from a microscale perspective, molecular dynamics is used to construct pure PP models and models filled with untreated carbon nanotubes (UFCNT), amino-functionalized carbon nanotubes (AFCNT), carboxyl-functionalized carbon nanotubes (CFCNT), and hydroxyl-functionalized carbon nanotubes (HFCNT) (functionalized MWCNT with 4 or 8 functional groups grafted onto them). The simulation results indicate that the doping of nanotubes can effectively enhance the thermodynamic properties of PP. Among them, PP/CFCNT-8 exhibits the most significant improvement in melting temperature and mechanical properties, with an increase in melting temperature of 88.85 K and a 184.52 % increase in Young's modulus. The melting temperature of PP/HFCNT-8 is second only to PP/CFCNT-8, with an increase of 82.59 K. The results indicate that the thermodynamic properties of PP nanocomposites filled with functionalized MWCNT are improved with the grafting rate. The filling of functionalized MWCNT alters the microscale properties of PP composites, with a significant decrease in root mean square displacement (RMSD), and improvement in free volume fraction (FFV) as well as interfacial binding energy, which can better maintain the electrical properties of PP insulation materials. Applying functionalized carbon nanotubes to filled PP can significantly increase the electrical insulation properties of PP cable materials, which provides meaningful guidance for adopting polypropylene cable insulation materials.

Molecular simulation of the effect of dioctyl phthalate on the properties of nitrile rubber

The mechanical and tribological properties of pure nitrile rubber (NBR) and dioctyl phthalate/nitrile rubber (DOP/NBR) composite materials with mass ratios of 5/95, 10/90, 15/85, 20/80, 25/75, and 30/70 were studied through molecular dynamics simulations at the molecular level. The root mean square displacement (RMSD) and gyration radius of the composite materials were investigated to explore the mechanism of DOP plasticizing NBR. Different models of pure NBR and DOP/NBR composite materials with different mass ratios were established, and the mechanical properties of the materials were calculated by using the constant strain method. The tribological properties of the materials were studied by applying shear velocity on the surface of the materials. The research results showed that the shear resistance of the DOP/NBR composite material increased and then decreased with the increase of the DOP mass ratio, and the same pattern was observed for the shear modulus. Compared with pure NBR materials, DOP/NBR composite materials demonstrated better mobility and flexibility, and the RMSD and gyration radius of the material increased and then decreased with the increase of the DOP mass ratio. The DOP plasticization of NBR reduced the intermolecular interaction forces and changed the molecular conformation, increasing the softness and plasticity of the polymer chains.

Free and random vibration analyses of hourglass lattice sandwich panel using an equivalent model based on variational asymptotic method

The hourglass lattice sandwich panel (hourglass LSP) represents a novel type of lightweight and high-strength structure, showcasing new random vibration characteristics related to its distinct geometric configuration. In this paper, a two-dimensional equivalent plate model (2D-EPM) is constructed based on the equivalent stiffness obtained by the variational asymptotic homogenization of the unit cell. The accuracy of 2D-EPM in analyzing the random vibration characteristics (power spectral density (PSD) and root mean square (RMS) responses, as well as effective mass fraction) is validated by the three-dimensional direct numerical simulation and experiments, and its computational efficiency is greatly improved due to the reduced degree of freedoms. On this basis, the effects of structural parameters on the free and random vibration characteristics are systematically analyzed by using the novelty of unit-cell tailorability. The investigation revealed direct correlations between the displacement PSD and RMS with the aspect ratio and lattice rod radius, whereas the inclination angle and face-to-core thickness ratio exhibited inverse correlations. Furthermore, similarities in the low-frequency behaviors of hourglass, pyramid and auxetic LSPs were evident. Specifically, the displacement–RMS curve of the auxetic LSP was comparatively lower, and the hourglass LSP exhibited a similar response, with the second-lowest RMS curve implying correspondingly strong deformation resistance.

Identification of crack location in metallic biomaterial cantilever beam subjected to moving load base on central difference approximation

Abstract If not detected early, the cracks in structural components may ultimately result in the failure of the structure. This issue becomes even more critical when the component under investigation is a prosthesis placed in the human body. This study presents a crack location identification method based on the time domain in a cantilever beam of metallic biomaterials (CBMB). The absolute difference between the central difference approximation of the root mean square (RMS) of displacement of points on the cracked and uncracked beams was applied as a cracked location indicator. Captured time-domain data (displacement) at each node of the cracked and uncracked beams were processed into a central difference approximation of the RMS of displacement. Then, the crack could be detected by a sudden change of the cracked location indicator. The feasibility and effectiveness of the proposed method were validated by numerical simulations. The finite-element simulation of a CBMB with a transverse notch was analyzed in the numerical study. The notch or crack was detected along the beam under a moving load at various locations. A set of simulation experiments and numerical calculations was performed to determine whether the proposed identification method would accurately detect the location of a crack in a cantilever beam under a moving load compared to the location found by an exact solution method. The results showed that the proposed method was not only as able as the analytical method but also robust against noise: it was able to detect a crack precisely under 5% noise.

Seismic signatures and site characterization of an intermittent stream in dry and flood conditions: an implication for soil losses and landslide triggering

Identifying ambient noise-based (ANb) signatures together with the erosion-prone site conditions retrieved from georadar attribute analysis of streams can help in the estimation of their erosive potential (EP) that promotes reverie landslides and soil losses in the fluvial valleys. This is particularly imperative on flooding or rainy days, leading to stronger erosion-prone conditions (colluvium and boulders) of the valley beds. Developing such research direction can benefit the local communities, as is the case with the Cerrado region of Brazil, where these phenomena have high destructive potential with social, economic, and climatic implications. For the present study, a seasonal stream in the Federal District of Brazil was investigated by ANb monitoring supported by ground penetration radar (GPR) for site characterization. The ANb monitoring was conducted (at a safe distance) with a seismometer over several durations of dry and rainy conditions. The power spectral density (PSDs) as a function of several weather conditions (rainfall, wind speed, and pressure), time–frequency spectrograms, and ambient noise displacement root mean square (dRMS) were computed. This analysis also considered the single station horizontal-to-vertical spectral ratio (HVSR), where rain, wind, pressure, river flow and anthropogenic signatures were evident (at selective frequency ranges). Multi-peaks that emerged on the HVSR curve were further analyzed to identify amplitude and frequency changes, with the three peaks shifting on average to a lower position during the rainy period. The GPR amplitude and waveform variation features were attributed to the stratigraphy of the floodplain and regions susceptible to erosion, such as erosion-prone lithological spots, which provide the basis for non-destructive monitoring tools that enable the detection of “seismic signatures” and weak spots of the fluvial channels for improving environmental management.

Isotopic effect on thermal physical properties of cubic SiC

Using path-integral Monte Carlo (PIMC) and classical Monte Carlo (CMC) simulations in the isothermal–isobaric (NPT) ensemble, we investigate the isotope effect on the thermal properties of the cubic silicon carbide (c-SiC) crystal. At T=50 K, the calculations show that the isotopic substitutions shift up the average vibrational energy and root-mean-square displacements (RMSD) values, with a more significant impact on carbon isotope substitution than the silicon ones. However, the total kinetic to total potential energy ratio suggests that the system behaves harmonically and insensitive to isotopic changes. We also calculated the effect of the quantum contribution on c-SiC crystal, considering the most abundant isotopes. At low temperatures, the c-SiC crystal behaves harmonically, although the C and Si atoms behave anharmonically. The quantum effects increase the lattice constant by almost 0.3%, the average RMSD by 0.0703(4) Å and are responsible for reducing the linear thermal expansion coefficient by about 5.8×10−6 K. The zero-point energy is found about 0.1225(3) eV/atom. A satisfactory agreement between the PIMC values and available theoretical and experimental results are found and discussed.

Optimal control of jacket platforms vibrations under the simultaneous effect of waves and earthquakes considering fluid-structure interaction

Offshore platforms are very important structures that experience different types of dynamic loads throughout their service lives. In this study, the effects of the simultaneous occurrence of earthquakes and wave loads are investigated. The influences of earthquake-related water shaking on microwaves have also been considered. For this purpose, a case study is performed on the Ressalat oil platform in the Persian Gulf. The modified endurance wave analysis (MEWA) is used to produce waves corresponding to the structure's location. Moreover, the interactions between the fluid and the structure (FSI), as well as the effect of the added mass caused by the oscillation of the platform in the fluid are considered in the analysis. In order to control platform vibrations, the ideas of semi-active control using magnetic fluid dampers (MR), along with the fractional order proportional-integral-derivative (FOPID) control algorithm, are investigated. For online calculation of the gains of the control algorithm, an observer composed of 2-interval type fuzzy systems (IT2FLS) is used, whose orders, the membership functions of the fuzzy system inputs, as well as the fuzzy rules set, are optimized by Observer-Teacher-Learner-Based Optimization (OTLBO). This technique is a powerful meta-heuristic algorithm. In the used control process, the effect of actuator saturation, which is one of the problems of semi-active control systems, is considered. To evaluate the effectiveness of the proposed control, the maximum value and the root-mean-square (RMS) responses of the platform under 5 waves with different return periods and 7 far-fault earthquake records are compared. The results show that in the cases of simultaneous wave and earthquake loads, the wave load can partly reduce the maximum displacements caused by earthquakes. Also, the maximum and RMS displacement of the jacket platforms' level under wave load with a return period of 100 years and 7 earthquakes are reduced by an average of 35%, which can increase the service life of these structures by 4 times.

Optimal design of SMA damper for vibration control of connected building under random seismic excitation

To alleviate the earthquake induced damages in closely spaced high-rise buildings, linear or non-linear dampers have been frequently employed. Out of different options, the frequently utilized non-linear damper is the yield damper. Yield damper shows good floor displacement control efficiency, but increases peak floor acceleration and leaves large residual deformation at the end of ground motion. Also, it shows degradation in the hysteresis loop; whereas to achieve a good acceleration and displacement control efficiency, it is imperative to have a stable hysteresis loop with negligible residual deformation. In this context, shape memory alloy (SMA) composed damper has been viewed as a potential solution to reduce floor displacement and acceleration, simultaneously. Also, it offers excellent recentering property and good seismic energy dissipation capacity. This research aims to use the above stated superior properties of SMA and investigate the seismic response control efficiency of optimally design SMA damper for connected buildings, and compare with the yield damper. Optimal stochastic responses of connected buildings are estimated under random earthquake, as modeled using the Kanai-Tajimi power spectra. To linearize the non-linear force–displacement behavior of SMA and yield damper, a statistical linearization approach is adopted. The RMS (root mean square) floor acceleration and RMS floor displacement ratios are determined as response outputs for the damper connected buildings. Studies results show that, optimally designed SMA damper is more effective in reducing acceleration of stiff building and displacement of the flexible building than the yield damper. Compared to the yield damper, SMA damper reduces the RMS acceleration ratios by 15 % for the flexible building and 35 % for the stiff building; and RMS displacement by 20 % for the flexible building and 0.5 % for the stiff building. Overall, SMA damper provide much better seismic response control efficiency for connected buildings than yield damper.

Phenolic compounds as histone deacetylase inhibitors: binding propensity and interaction insights from molecular docking and dynamics simulations.

Histone deacetylases are well-established target enzymes involved in the pathology of different diseases including cancer and neurodegenerative disorders. The approved HDAC inhibitor drugs are associated with cellular toxicities. Different phenolic compounds have been shown to possess inhibitory activities against HDACs and are, therefore, considered safer alternatives to synthetic compounds. Here, we elucidated the binding mode and calculated the binding propensity of some of the top phenolic compounds against different isoforms representing different classes of Zn2+ ion-containing HDACs using the molecular docking approach. Our data reaffirmed the activity of the studied phenolic compounds against HDACs. Binding interaction analysis suggested that these compounds can block the activity of HDACs with or without binding to the active site zinc metal ion. Furthermore, molecular dynamics (MD) simulations were carried out on the selected crystal and docking complexes of each selected HDAC isoform. Analysis of root-mean-square displacement (RMSD) showed that the phenolic compounds demonstrated a stable binding mode over 50ns in a way that is comparable to the cocrystal ligands. Together, these findings can aid future efforts in the search for natural inhibitors of HDACs.