Mechanical Analysis Research Articles

Lack of CYP3A4 protein induction despite mRNA induction in primary hepatocytes exposed to rifabutin as a possible explanation for its low interaction risk in vivo.

Rifampicin is a strong inducer of cytochrome P450 (CYP3A4) and P-glycoprotein (P-gp/ABCB1), leading to profound drug-drug interactions. In contrast, the chemically related rifabutin does not show such pronounced induction properties in vivo. The aim of our study was to conduct a comprehensive analysis of the different induction potentials of rifampicin and rifabutin in primary human hepatocytes and to analyze the mechanism of potential differences. Therefore, we evaluated CYP3A4/ABCB1 mRNA expression (polymerase chain reaction), CYP3A4/P-gp protein expression (immunoaffinity-liquid chromatography-mass spectrometry, IA-LC-MS/MS), CYP3A4 activity (testosterone hydroxylation), and considered intracellular drug uptake after treatment with increasing rifamycin concentrations (0.01-10µM). Furthermore, rifamycin effects on the protein levels of CYP2C8, CYP2C9, and CYP2C19 were analyzed (IA-LC-MS/MS). Mechanistic analysis included the evaluation of possible suicide CYP3A4 inhibition (IC50 shift assay) and drug impact on translational efficiency (cell-free luminescence assays). Rifabutin accumulated 6- to 15-fold higher in hepatocytes than rifampicin, but induced CYP3A4 mRNA comparably to rifampicin (e. g. rifampicin 61-fold vs. rifabutin 44-fold, 72h). While rifampicin for example enhanced protein (10µM: 21-fold) and activity levels considerably (53-fold), rifabutin only slightly increased CYP3A4 protein expression (10µM: 3.3-fold) or activity (11-fold) compared to rifampicin after 72h. Both rifamycins similarly influenced expression of other eliminating proteins. A potential CYP3A4 suicide inhibition by a specific rifabutin metabolite or disruption of ribosome function were excluded experimentally. In conclusion, the lack of protein enhancement, could explain rifabutin's weaker induction-related drug-drug interaction risk in vivo.

Nonlinear mechanical response analysis and convolutional neural network enabled diagnosis of single-span rotor bearing system

The wide application of rotating machinery has boosted the development of electricity and aviation, however, long-term operation can lead to a variety of faults. The use of different measures to deal with corresponding malfunctions is the key to generating benefits, so it is significant to carry out the fault diagnosis of rotating machinery. In this work, a test bench for single-span rotor bearings was established, three faults, including spindle bending, spindle crack without end loading and spindle crack with end loading, are experimental analyzed with basic mechanical response. Moreover, a diagnosis is performed using a convolutional neural network, according to the differences in mechanical responses of the three faults obtained from experiments. For three faults, the change in the properties of spindle itself results in different axis trajectories and spectra. Compared with spindle bending fault, spindle crack fault not only cause 1×, 2×, 3× frequency component excitation, also 4×, 5× frequency component excitation. Additionally, the classification accuracy of the training set and the test set under machine learning for the three types of working conditions is 100%. This indicates that the network can significantly identify signal features so as to make effective fault classification.

Mechanical analysis of a PEEK titanium alloy macro-composite hip stem by finite element method

Mechanical analysis of a PEEK titanium alloy macro-composite hip stem by finite element method

Digital economy and urban innovation level: A quasi-natural experiment from the strategy of “Digital China”

The digital economy is an essential engine of the innovation-driven development strategy and plays a valuable role in promoting the high-quality development of the regional economy. Based on the panel data of 286 cities in mainland China with the help of the digital economy strategic plans issued by local governments as a quasi-natural experiment, we use the multi-temporal double-difference (DID) method to examine the impact of the digital economy on the urban innovation level. Findings show that the digital economy can significantly improve the urban innovation level. After a series of robustness tests, such as parallel trend test, updating sample and period, and repeated placebo test, the innovation-driving effect generated by the development of the digital economy remains significant. Results of the mechanism analysis indicate that the digital economy enhances the level of innovation through upgrading industrial structures. In addition, we find through the heterogeneity test that the digital economy has a stronger effect on improving the quality of innovation. Meanwhile, the innovation output in the Middle Eastern region is more significantly affected by the “Digital China” strategy than the Western region. Therefore, we should accelerate the implementation of the local digital economy development strategy to realize the high-quality development of the regional economy.

Design and Analysis of a Metamorphic Wrist Rehabilitation Parallel Mechanism

Design and Analysis of a Metamorphic Wrist Rehabilitation Parallel Mechanism

Self‐media information disclosure and firm productivity

AbstractUsing Sina Weibo data obtained through crawler technologies from 2013 to 2021, this study investigates the relationship between self‐media information disclosure and firm productivity. We find that self‐media information disclosure promotes firm productivity, a conclusion that withstands various robustness and endogeneity tests. Particularly, original microblogs exhibit a more significant impact. Further analysis reveals that the promoting effect is more pronounced in listed companies with lower annual retweets, small companies, and those with lower turnover. Finally, a mechanism analysis indicates that self‐media information disclosure enhances enterprise productivity by alleviating financing constraints, enhancing corporate innovation, and strengthening corporate governance.

Olive oil consumption is associated with lower cancer, cardiovascular and all-cause mortality among Italian adults: prospective results from the Moli-sani Study and analysis of potential biological mechanisms.

Olive oil consumption has been reportedly associated with lower mortality rates, mostly from cardiovascular diseases, but its potential impact on cancer death remains controversial. Moreover, biological mechanisms possibly linking olive oil consumption to mortality outcomes remain unexplored. We longitudinally analysed data on 22,892 men and women from the Moli-sani Study in Italy (follow-up 13.1 y), to examine the association of olive oil consumption with mortality. Dietary data were collected at baseline (2005-2010) through a 188-item FFQ, and olive oil consumption was standardised to a 10 g tablespoon (tbsp) size. Diet quality was assessed through a Mediterranean diet score. Multivariable-adjusted Cox proportional hazard models, also including diet quality, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The potential mediating role of inflammatory, metabolic, cardiovascular and renal biomarkers on the association between olive oil intake and mortality was evaluated on the basis of change-in-estimate and associated p values. Multivariable HRs for all-cause, cancer, cardiovascular and other cause mortality associated with high (>3 tbsp/d) versus low (≤1.5 tbsp/d) olive oil consumption were 0.80 (0.69-0.94), 0.77 (0.59-0.99), 0.75 (0.58-0.97) and 0.97 (0.73-1.29), respectively. Taken together, the investigated biomarkers attenuated the association of olive oil consumption with all-cause and cancer mortality by 21.2% and 13.7%, respectively. Higher olive oil consumption was associated with lower cancer, cardiovascular and all-cause mortality rates, independent of overall diet quality. Known risk factors for chronic diseases only in part mediated such associations suggesting that other biological pathways are potentially involved in this relationship.

Analysis of thermal damage formation and extension mechanism in CFRP short pulse laser cutting based on an inhomogeneous mesoscopic ablation model

Analysis of thermal damage formation and extension mechanism in CFRP short pulse laser cutting based on an inhomogeneous mesoscopic ablation model

Mechanistic analysis of acid gas storage and oil recovery in naturally fractured reservoirs using single matrix block approach

AbstractThe objective of this study is to assess the storage of acid gas, containing CO2 and H2S, in a depleted naturally fractured reservoir (NFR) using single matrix block (SMB) approach. The acid gas dissolution in oil is considered by Peng‐Robinson equation of state and compositional simulation. The PHREEQC package is used to determine acid gas solubility in formation brine. Three types of acid gases with different compositions are used for this study and their swelling behavior and miscibility in relation to the reservoir oil are analyzed. An SMB model, with a matrix block surrounded by fractures, is constructed, and validated for simulation of a real experiment. The simulation is conducted for synthetic and real reservoir fluids when the oil is in its residual saturation. A sensitivity analysis is performed to study the effects of key parameters, such as acid gas composition, reservoir pressure, permeability, porosity and matrix height on the storage capacity and oil recovery factor. The matrix has a volume of 27 m3 and about half of acid gas storage is achieved in the first 5 years while the simulations are run for 30 years. The results show that up to 90% of remained oil is recoverable, and more than 0.67 kmol of acid gas per cubic meter of matrix is stored whether matrix contains a real oil or a synthetic one. Higher storage is achieved for higher matrix porosities and heights and large H2S proportion in acid gas. In all cases about 10% of acid gas is trapped in water and the remaining 90% is dissolved in oil. The mineral trapping was more active in CO2‐rich acid gases. While about 10 kg of the matrix rock was dissolved in the acidic brine when the acid gas contained H2S, the amount of the dissolved minerals in acidic brine resulted from the injection of CO2‐rich acid gas was more than 16 kg. Finally, this study gives a comparative analysis of the storage performance of acid gas mixture and pure CO2. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Kinematics analysis and optimization of the lower hook mechanism in netting machine

Kinematics analysis and optimization of the lower hook mechanism in netting machine

Finite element analysis of modified Slongo's external fixation in the treatment of supracondylar humeral fractures in older children.

Older children over 8 years old are at higher risk of elbow joint stiffness after treatment of supracondylar humeral fractures. The objective of this study was to improve the Slongo's external fixation system for treating supracondylar humeral fractures in older children. This would be achieved by increasing fixation strength and providing a theoretical basis through finite element analysis and mechanical testing. A 13-year-old female patient with a history of previous fracture was selected for CT data processing to create a three-dimensional model of the distal humerus fracture. Two internal fixation models were established, using the Slongo's external fixation method with Kirschner wire (Group A) and modifying the Slongo's external fixation (Kirschner wire tail fixation) (Group B). The fracture models were then subjected to mechanical loading analysis using Finite Element Analysis Abaqus 6.14 software to simulate separation, internal rotation, and torsion loads. A PVC humeral bone model was used to create a supracondylar fracture model, and the A and B internal fixation methods were applied separately. The anterior-posterior and torsional stresses were measured using the Bose Electroforce3510 testing system, followed by a comparative analysis. The finite element simulation results showed that under the same tensile, torsion, and inversion forces, the osteotomy model fixed with Kirschner wire at the distal end in Group B exhibited smaller tensile stress and deformation compared to the unfixed osteotomy model in Group A. This indicated that the fixation strength of Group B was superior to that of Group A. According to the test results of the Bose Electroforce3510 testing system, a simple linear regression analysis was conducted using SPSS software. The K values of rotation angle-torque tests and front and rear displacement-stress tests were calculated for Groups A and B, with Group B showing higher values than Group A. The results of this study supported the significantly enhanced biomechanical reliability and stability of fracture fixation in Group B, which utilized the modified Slongo's external fixation (Kirschner wire tail fixation). This optimized method provides a new choice for the clinical treatment of supracondylar humeral fractures in older children, backed by both clinical evidence and theoretical basis.

THE STUDYOF INSULATING PROPERTIES OF REFRACTORY BRICKS PRODUCED USING MELON SEED HUSKSAS POREFORMER

This study investigated the physical, mechanical and thermal characteristics of insulating refractory bricks produced from Nigerian clay blended with melon seed husk. The aim is to reduce the cost of production which arises from importation. This is due to lack of high-quality domestic insulating refractory bricks in most high temperature industries in Nigeria. The test samples were produced by mixing clay and melon seed husk having grain sizes of 212 - 300 μm. The samples were oven dried and fired at temperatures 950℃ to 1150℃ at 50℃ intervals. Physical, mechanical, thermal tests, chemical compositions, Mineralogical and Microstructural analysis were conducted. The results showed that, clay with 25 and 30 wt.% melon seed husks possessed the required refractory properties with cold crushing strength above the recommended ASTM Standard of 1000 kN/m2.

Development of HDPE/natural fiberboard nanocomposite reinforced Bi2O3/BaO and H3BO3: A sustainable approach for gamma and neutron shielding application

AbstractRadiation shielding materials significantly contribute to various fields. In this research, a new eco‐friendly nanocomposite shielding material based on high‐density polyethylene (HDPE) and natural fiberboard (NF) with different concentrations of barium oxide nanowires (BaO), bismuth oxide nanorods (Bi2O3), and boric acid (H3BO3) is constructed and investigated for 137Cs, 60Co gamma ray, and 142Am–Be neutron sources. Mechanical and physical testing and thermal analysis were conducted to assess the impact of nanostructure incorporation on the structural integrity and thermal stability of the nanocomposite. The 60Co gamma and neutron attenuation properties were evaluated using the appropriate radiation sources. The transmission and absorption coefficients of the nanocomposites were measured. The results demonstrated that HDPE/NF filled with BaO, Bi2O3 nanostructure, and boric acid has higher tensile strength and thermal stability than unfilled HDPE/NF. The results displayed that the HDPE/NF filled with 1.5% Bi2O3 and 1.5% BaO improved gamma attenuation and also HDPE/NF/10% boric acid had a high value. The outcomes of this research provide valuable insights into the design and fabrication of radiation shielding materials by understanding the relationship between nanoparticle concentration, radiation attenuation properties, and the mechanical and thermal characteristics of the nanocomposite. This study aims to optimize the performance and applicability of HDPE/NF nanocomposites for radiation protection applications.Highlights Synthesis of BaO nanowires and bismuth oxide (Bi2O3) nanorods by hydrothermal simple method. Fabrication and characterization of a new HDPE/natural fiberboard (NF) nanocomposite containing BaO/Bi2O3/H3BO3 as an eco‐friendly additive. The HDPE/NF/1.5% BaO/1.5% Bi2O3 nanocomposite has better tensile strength and more thermal stability. Usage of HDPE/NF/1.5% BaO/1.5% Bi2O3 nanocomposite that should be utilized for radiation shielding. Usage of HDPE/NF/1.5% BaO/1.5% Bi2O3/10% H3BO3 nanocomposite that should be utilized for neutron attenuation performance.

W-Leg Jumping Robot: Mechanical Design, Dynamical Analysis and Simulation of Jumping Dual Wheel-Leg Hybrid Robot

AbstractThis study primarily focuses on design, mathematically model and simulate a novel two wheel-legged hybrid robot called W-Leg Jumping robot, which has a unique ability to overcome step-like obstacles efficiently. In general, in transformable wheel-leg robot studies, the leg and wheel structure perform their movements in an interdependent manner. However, in this study, it is aimed to design a robot in which the leg and wheel structure can move independently of each other and to develop a robot that can easily overcome obstacles on flat surfaces with the wheel mode and with the leg mode. The robot can fold its legs hidden within the wheels and deploy its two degree of freedom (DoF) legs when it detects step-like obstacles. This mechanism allows the robot to overcome an obstacle with a height of twice the radius of the robot's open/close mechanism of the legs, along with the two-dimensional kinematic and dynamic analyzes of the legs, are presented in detail within the scope of this study proportional-integral-derivative (PID) controller is designed to control the joint angles of the legs. The reference angle values to be followed according to the height of the obstacle are determined using artificial neural network (ANN). Additionally, motion simulations of the robot are conducted for four different obstacle heights (20, 30, 40, and 50 cm). As a result of the PID controller, when exceeding the highest obstacle of 50 cm, the average absolute joint angular tracking error is max. 1.8829°, average tracking error max. 0.265 s and max.

Molecular mechanism analysis of nontuberculous mycobacteria infection in patients with cystic fibrosis.

Aim: This study aims to explore the molecular mechanisms of cystic fibrosis (CF) complicated with nontuberculous mycobacteria (NTM) infection. Materials & methods: Expression profiles of CF with NTM-infected patients were downloaded from GEO database. Intersection analysis yielded 78 genes associated with CF with NTM infection. The protein-protein interaction (PPI) network and the functions of hub genes were investigated. Results: Five hub genes (PIK3R1, IL1A, CXCR4, ACTN1, PFN1) were identified, which were primarily enriched in actin-related biological processes and pathways. Transcription factors RELA, JUN, NFKB1 and FOS that regulated hub genes modulated IL1A expression, while 21 other transcription factors regulated CXCR4 expression. Conclusion: In summary, this study may provide new insights into the mechanisms of CF with NTM infection.

Optimizing the boron-loaded pH/temperature dual responsive polymer for controlled release of boron from wood

ABSTRACT Disodium octoborate tetrahydrate (DOT) is a well-received and eco-friendly preservative. However, it is prone to leaching from wood in humid conditions or rainy seasons, causing problems such as decreased efficiency in resisting fungi and poor surface performance in surface finishing. To obtain enhanced leaching resistance and simultaneously achieve controlled release of DOT, a pH and temperature dual responsive poly (2-hydroxyethyl methacrylate/2-(Dimethylamino) ethyl methacrylate) (PDH) was prepared and optimized for in situ construction of DOT-loaded PDH (PDHD) in wood. Results showed that PDH displayed obvious pH and temperature-responsive swelling, and when loaded with DOT, the PDHD consequently released DOT in a pH and temperature-responsive way. Fourier transform infrared spectroscopy, Solid-13C NMR analysis and Dynamic mechanical analysis confirmed the copolymerization of 2-Hydroxyethyl methacrylate (HEMA) and 2-(Dimethylamino) ethyl methacrylate (DMAEMA), as well as the presence of crosslinked structure formed from hydrogen bond between the hydroxyl group of HEMA and the N,N-dimethylamino groups of DMAEMA. After that, the PDHD was in situ constructed in wood for controlled release of boron. During the water leaching test, the modified wood exhibited a boron fixation rate of 49.05% compared with 0.72% of the neat DOT-treated wood. Besides, it presented controlled release activity in response to pH and temperature. This work provides new approaches to the fixation of boron preservatives and notably realizes responsive releasing of boron compounds for long-term wood preservation.

Mechanism analysis of injection technique of water composition modification for enhanced oil recovery

ABSTRACT By adjusting the composition of injection water, including ionic type and strength, the goal of enhance oil recovery rate can be achieved. However, there is no clear understanding of which factor, ionic type or strength, has a greater impact. In this paper, based on the formation water of the offshore G oilfield, various brines with different ionic strengths and types were prepared. By measuring the zeta potential of rock powder and oil droplets, three-phase contact angle, interfacial tension between oil and water, emulsification properties of brines, and film strength of oil-water interface, the variation rules of the core wettability and emulsification performance of brine were systematically analyzed when the ionic strength and ionic type were changed. The experimental results showed that ionic strength has a greater impact than that of ionic type. For the oil-water-solid (rock) system of the G oilfield, an ionic strength of 82 mM/kg is the threshold for low salinity effect. Reducing ionic strength resulted in an increase in the hydrophilicity of rock and the ability of water flooding to emulsify oil droplets, which contribute to the improvement of oil displacement efficiency. Theoretically, water flooding to enhance oil recovery can be achieved by only reducing the ionic strength. This understanding was verified by dual polarization interferometry (DPI) experiments and low-field nuclear magnetic resonance experiments, which showed that reducing the salinity of the injection water from 42,000 mg/L (ionic strength of 820 mM/kg) to 4200 mg/L (ionic strength of 82 mM/kg) enhanced the oil recovery by 7.9%.

Mechanism Analysis of the Effect of Wake Vortex on Cylinder Vibration in Flow Induced Motion

Abstract Unsteady Reynolds-averaged Navier–Stokes (RANS) method combined with Spalart–Allmaras turbulence model and dynamic mesh technology was used to investigate the impact of wake vortex on the vibration response of a cylinder. By analyzing the phase difference between the wake vortex force and the displacement under different mass parameters in flow-induced vibration (FIV), the study reveals that the influence of wake vortex on the cylinder varies significantly in different vibration branches. The wake vortex of the initial branch enhances the cylinder's vibration, whereas the wake vortices of the upper, lower, and desynchronized branches suppress the vibration. At the critical point between the initial branch and the upper branch of vortex-induced vibration (VIV), there is a 90 degree phase jump, and the instantaneous phase difference fluctuation between the wake vortex force and displacement of the VIV branch remains relatively constant. In the galloping branch, there are wake vortices in different directions that affect the cylinder's vibration every quarter of the vibration period, and the phase difference undergoes periodic large fluctuations (either in-phase or out-of-phase), with the result that the wake vortex force periodically promotes or restrains the cylinder's vibration, which can serve as a novel criterion for identifying the occurrence of galloping. Furthermore, when varying the mass parameters at a constant reduced velocity, the impact of the wake vortex in the initial branch is relatively insignificant. However, as the mass ratio increases in other vibration branches, the suppressive effect increases, and the wake vortex force can prevent VIV induced galloping phenomenon by affecting the vibration intensity.

Abstract PO1-13-12: Mechanistic Analysis and Potential Therapeutic Implications in Breast Cancer with Fibrotic Focus

Abstract A fibrotic focus (FF) is a scar-like region that forms in the center of carcinoma due to excessive tumor stroma formation. In our earlier studies, we found FF as an independent poor prognostic factor for breast cancers. However, the underlying mechanisms of how the presence of FF contributed to a poor prognosis are still unknown. To improve our understanding of FF in breast cancer, we have investigated genes associated with FF and their impacts on breast cancer prognosis. Analysis of data from The Cancer Genome Atlas Program (TCGA) indicated that Bone Morphogenetic Protein 8A (BMP8A) was significantly upregulated in breast cancers with FF. To further validate this finding, immunohistochemistry (IHC) on BMP8A was performed on a local cohort of breast cancers (N= 900). Of these samples, 147 (16.3%) were found to be BMP8A positive, and there was a significant association between the presence of FF and high expression of BMP8A (p-value=0.026). We also found that high expression of BMP8A was positively correlated with apocrine phenotype, necrosis, increased Ki67 expression, and triple-negative breast cancer subtype; and most of these are poor prognostic factors for breast cancer. Kaplan-Meier survival estimate analysis revealed that high expression of BMP8A was significantly associated with poor overall survival (p-value=0.035). Gene ontology (GO) analysis showed that "Extracellular matrix organization" was the prominent biological process associated with BMP8A. KEGG pathway analysis suggested that BMP8A was significantly related to "Protein digestion and absorption", "ECM-receptor interaction", and "Focal adhesion" pathways, further validating its correlation with stromal FF. In cellular studies using MCF7 and MDA-MB-231 cell lines, overexpression of BMP8A was found to enhance breast cancer cell proliferation, invasion, and migration. Similar tumor-promoting phenotypes were exhibited when stimulating the cell lines with recombinant human BMP8A. In conclusion, our findings suggested that BMP8A was associated with FF in breast cancer, contributing at least partly to the aggressive features of these cancers. Our findings also provided new insights into the precision treatment and diagnosis of breast cancer. Further exploration of BMP8A as a therapeutic target and prognostic factor may contribute to improved management of breast cancer patients. Citation Format: Canbin Fang, Julia Y. S. Tsang, Gary M.K. Tse. Mechanistic Analysis and Potential Therapeutic Implications in Breast Cancer with Fibrotic Focus [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-13-12.

Does tax enforcement reduce corporate environmental investment? evidence from a quasi-natural experiment

The transition to a green, sustainable economy is largely reliant on corporate investment in the realm of environmental protection. Utilizing the adoption of the third phase of the Golden Tax Project (GTPIII) in China as a quasi-natural experiment, this paper examines how corporate environmental investment changes in response to greater tax enforcement. Our results reveal that tougher tax enforcement significantly lowers corporate environmental investment. Such an effect is stronger for firms faced by high financial constraints and those operating in non-heavy-polluting industries. Moreover, the mechanism analysis indicates that the higher tax burden induced by greater tax enforcement is the potential channel. Overall, this paper shows that stricter tax enforcement could potentially result in adverse spillover effects on corporate environmental investment, which warrants attention in tax collection practices.