Study and numerical analysis of Von Mises stress of a new tumor-type distal femoral prosthesis comprising a peek composite reinforced with carbon fibers: finite element analysis

Research on carbon-fiber-reinforced polyetheretherketone (CF-PEEK/CFR-PEEK) as a bone tumor joint prosthesis remains limited. Herein we numerically determine the feasibility of CF-PEEK material containing 30% Wt carbon fiber (CF30-PEEK) as a material for the dual-action tumor-type distal femoral prosthesis. Use CT scan method to build a complete finite element model of the knee joint. Simulate the resection of the distal femoral tumor, and then reconstruct it with the dual-action tumor-type distal femoral prosthesis. The femoral condyle and extension rod components were simulated with cobalt chromium molybdenum (CoCrMo), PEEK and CF30-PEEK materials respectively. When simulating the standing state, a vertical stress of 700 N is applied to the femoral head. When simulating the squatting state, a vertical stress of 2800 N is applied to the femoral head. The displacement and rotation angle of each node of the distal tibia are fully restrained in three directions (X-axis, Y-axis, Z-axis). We examined the stress magnitude, stress distribution, and stability of the prosthesis and each of its components by means of finite element analysis (FE analysis). The FE analysis results show: after replacing the distal femur and the extension rod with CF30-PEEK material, the stress is still evenly distributed, and the average stress is significantly reduced. In addition, the stability is similar to CoCrMo material. Therefore, CF30-PEEK is an appropriate material for this type of prosthesis.</p

sj-docx-1-jom-10.1177_01492063231173422 - Supplemental material for What Do Investors Value? A Multidisciplinary Review

Supplemental material, sj-docx-1-jom-10.1177_01492063231173422 for What Do Investors Value? A Multidisciplinary Review by Wei Guo and Tieying Yu in Journal of Management</p

Roles of Small Molecules in the Stability and Sensitivity of CL-20-Based Host–Guest Explosives under Electric Fields: A Reactive Molecular Dynamics Study

Host–guest inclusion, constructed by inserting small molecules into voids of energetic crystals, is a novel strategy for creating new energetic materials (EMs) with desired energy and safety. To provide an atomistic-level insight into the fact that small guest molecules can effectively regulate the stability and sensitivity of CL-20, we conducted ReaxFF-lg reactive molecular dynamics simulations on electric-field (EF)-induced decomposition of two typical host–guest EMs, CL-20/H2O2 and CL-20/N2O, and compared it to that of α-CL-20 and ε-CL-20. Our findings show that the sensitivity order of the CL-20-based EMs under EFs, α-CL-20/H2O2 > ε-CL-20 > α-CL-20 > α-CL-20/N2O, agrees well with the sensitivity obtained from the experiment (ε-CL-20 > α-CL-20 > α-CL-20/N2O). Different effects of H2O2 and N2O molecules were found responsible for the distinct stability and sensitivity of these materials toward EFs. On the one hand, H2O2 accelerate(s) the structural transformation of CL-20 and thus increases the sensitivity, because the wobbling NO2 group reduces the stability of CL-20 by weakening its adjacent C–N bonds, whereas N2O makes this transition less likely, resulting in low sensitivity of α-CL-20/N2O. On the other hand, H2O2 and its decomposition intermediate OH radical can promote destruction of CL-20’s cage structure and produce a large amount of water molecules to release heat, making CL-20/H2O2 to decompose faster than ε-CL-20. N2O molecules rarely react with CL-20 molecules but absorb heat from the surrounding decomposed CL-20 and thus slow down CL-20’s decomposition, resulting in low sensitivity of α-CL-20/N2O, as confirmed by transition-state calculations. The results provide a comprehensive understanding of the stability and sensitivity of CL-20-based host–guest explosives under EFs

Detection and quantification of the giant protein titin by SDS-agarose gel electrophoresis

Titin, a giant sarcomeric protein, is involved in the generation of passive tension during muscle contraction, assembly and stability of the sarcomere in striated muscles. Titin gene produces numerous titin protein isoforms with different sizes ($3–4 MDa) resulting from alternative splicing. To study titin and titin isoform changes under disease conditions, the method to detect and quantify titin protein isoforms is needed. The method reported here is a 1% vertical SDS-agarose gel electrophoresis system that can solubilize, detect and quantify various titin isoform sizes. Sodium dodecyl sulfate (SDS)-agarose gel electrophoresis is an important tool in revealing the size and quantity of giant proteins in the sarcomere. In this method article, heart tissues were dissolved in urea- thiourea-glycerol sample buffer. Muscle proteins were resolved on 1% SDS-agarose gels that were silver-stained subsequently. Titin isoform bands with different sizes were separated on the gel. At the end, we also validated the method for large protein detection. Our results indicated that this electrophoresis method is efficient to study the transitions in titin isoforms. This method provides efficient protein extraction with urea-thiourea-glycerol buffer from hard tissues such as striated muscles This method provides an efficient way to separate large proteins over 500 kDa Combining with silver staining, our method can detect large protein isoforms and quantify the separated protein bands. </div

Mechanochemical Synthesis of Ni–Y/CeO₂ Catalyst for Nonthermal Plasma Catalytic CO₂ Methanation

Nonthermal plasma (NTP)-assisted CO2 methanation can activate and convert stable CO2 molecules under ambient conditions as compared to conventional thermal catalysis (normal operation temperature up to 450 °C), which is a good technique to reduce CO2 emissions and simultaneously utilize the renewable energies like solar and wind. It is critical to develop a robust catalyst with good catalytic performance in order to make NTP catalytic CO2 methanation more competitive. Herein, we present a simple yet efficient synthesis of CeO2-supported Ni catalysts with yttrium (Y) as the promoter (i.e., Ni–Y/CeO2) via mechanochemical synthesis for efficient NTP catalytic CO2 methanation. The developed 7.5Ni–1Y/CeO2 catalyst demonstrated the highest energy efficiency values for CO2 conversion and CH4 yield, i.e., ∼57 gCO2 kWh–1 and ∼17 gCH4 kWh–1, respectively. The CO2-TPD and HRTEM results confirmed that the doped Y positively enhanced the basicity of the catalysts and also decreased the particle size of Ni nanoparticles, thus promoting the NTP catalytic activity of CO2 methanation. The catalyst displayed excellent short-term stability for plasma catalytic CO2 methanation over a 12 h on-stream evaluation, showing a CO2 conversion of 84.2 ± 1.8% and a CH4 selectivity of 83.3 ± 1.9%

sj-xlsx-1-sgo-10.1177_21582440221088013 – Supplemental material for Regional Tourism Performance Research: Knowledge Foundation, Discipline Structure, and Academic Frontier

Supplemental material, sj-xlsx-1-sgo-10.1177_21582440221088013 for Regional Tourism Performance Research: Knowledge Foundation, Discipline Structure, and Academic Frontier by Wei Guo and Xin Zhang in SAGE Open</p

Detection and quantification of the giant protein titin by SDS-agarose gel electrophoresis

Titin, a giant sarcomeric protein, is involved in the generation of passive tension during muscle contraction, assembly and stability of the sarcomere in striated muscles. Titin gene produces numerous titin protein isoforms with different sizes ( 3–4 MDa) resulting from alternative splicing. To study titin and titin isoform changes under disease conditions, the method to detect and quantify titin protein isoforms is needed. The method reported here is a 1% vertical SDS-agarose gel electrophoresis system that can solubilize, detect and quantify various titin isoform sizes. Sodium dodecyl sulfate (SDS)-agarose gel electrophoresis is an important tool in revealing the size and quantity of giant proteins in the sarcomere. In this method article, heart tissues were dissolved in urea-thiourea-glycerol sample buffer. Muscle proteins were resolved on 1% SDS-agarose gels that were silver-stained subsequently. Titin isoform bands with different sizes were separated on the gel. At the end, we also validated the method for large protein detection. Our results indicated that this electrophoresis method is efficient to study the transitions in titin isoforms. This method provides efficient protein extraction with urea-thiourea-glycerol buffer from hard tissues such as striated muscles This method provides an efficient way to separate large proteins over 500 kDa Combining with silver staining, our method can detect large protein isoforms and quantify the separated protein bands. </p

Liquid-Phase Pulsed Laser Ablation and Electrophoretic Deposition for Chalcopyrite Thin-Film Solar Cell Application

We report ligand-free synthesis of colloidal metallic nanoparticles using liquid-phase pulsed laser ablation, and electrophoretic deposition of the nanoparticles for fabrication of Cu­(In,Ga)­Se₂ (CIGS) thin film solar cells. First, colloidal metallic nanoparticles of Cu–In and Cu–Ga alloys are produced by pulsed laser ablation in common organic solvents without using stabilizing ligands. The nanoparticles are examined for phase, composition, and electrical surface charging and charge modulation mechanisms. Metallic precursor thin films with high purity and precise composition are produced by electrophoretic deposition of the colloids without transferring to another solvent and without using binders. Finally, we demonstrate fabrication of CIGS solar cells on Mo sheet substrates with an (active area) energy conversion efficiency up to 7.37%

Table1_Effect of carbon-fiber-reinforced polyetheretherketone on stress distribution in a redesigned tumor-type knee prosthesis: a finite element analysis.docx

Background: Surgery for bone tumors around the knee often involves extensive resection, making the subsequent prosthetic reconstruction challenging. While carbon fiber-reinforced polyetheretherketone (CF-PEEK) has been widely used in orthopedic implants, its application in tumor-type prosthesis is limited. This study aims to evaluate the feasibility of using 30wt% and 60wt% carbon fiber-reinforced polyetheretherketone (CF30-PEEK and CF60-PEEK) as materials for a redesigned tumor-type knee prosthesis through numerical analysis.Methods: A knee joint model based on CT data was created, and the resection and prosthetic reconstruction were simulated. Three finite element models of the prostheses, representing the initial and updated designs with CoCrMo and CFR-PEEK components, were constructed. Loading conditions during standing and squatting were simulated with forces of 700 N and 2800 N, respectively. Finite element analysis was used to analyze the von Mises stress and stability of all components for each prosthesis type.Results: After improvements in both material and design, the new Type 3 prosthesis showed significantly lower overall stress with stress being evenly distributed. Compared with the initial design, the maximum von Mises stress in Type 3 was reduced by 53.9% during standing and 74.2% during squatting. In the standing position, the maximum stress in the CF30-PEEK femoral component decreased by 57.3% compared with the initial design which was composed of CoCrMo, while the stress in the CF60-PEEK cardan shaft remained consistent. In the squatting position, the maximum stress in the femoral component decreased by 81.9%, and the stress in the cardan shaft decreased by 46.5%.Conclusion: The incorporation of CF30-PEEK effectively transmits forces and reduces stress concentration on the femoral component, while CF60-PEEK in the redesigned cardan shaft significantly reduces stress while maintaining stiffness. The redesigned prosthesis effectively conducts loading force and demonstrates favorable biomechanical characteristics, indicating the promising potential of utilizing CF30-PEEK and CF60-PEEK materials for tumor-type knee prostheses. The findings of this study could provide novel insights for the design and development of tumor-type knee prostheses.</p

RBM20, a potential target for treatment of cardiomyopathy via titin isoform switching

<p>Cardiomyopathy, also known as heart muscle disease,</p> <p>is an unfavorable condition leading to alterations in myocardial</p> <p>contraction and/or impaired ability of ventricular filling.</p> <p>The onset and development of cardiomyopathy have not</p> <p>currently been well defined. Titin is a giant multifunctional</p> <p>sarcomeric filament protein that provides passive stiffness to</p> <p>cardiomyocytes and has been implicated to play an important</p> <p>role in the origin and development of cardiomyopathy and</p> <p>heart failure. Titin-based passive stiffness can be mainly adjusted</p> <p>by isoform switching and post-translational modifications</p> <p>in the spring regions. Recently, genetic mutations of TTN</p> <p>have been identified that can also contribute to variable passive</p> <p>stiffness, though the detailed mechanisms remain unclear.</p> <p>In this review, we will discuss titin isoform switching as it</p> <p>relates to alternative splicing during development stages and</p> <p>differences between species and muscle types.We provide an</p> <p>update on the regulatory mechanisms of TTN splicing controlled</p> <p>by RBM20 and cover the roles of TTN splicing in</p> <p>adjusting the diastolic stiffness and systolic compliance of</p> <p>the healthy and the failing heart. Finally, this review attempts</p> <p>to provide future directions for RBM20 as a potential target</p> <p>for pharmacological intervention in cardiomyopathy and heart</p> <p>failure.</p