Mechanical Stress Research Articles

An Actual Insight into the Pathogenic Pathways of Ankylosing Spondylitis

Spondyloarthritis refers to a broad group of conditions that include ankylosing spondylitis, psoriatic arthritis, reactive arthritis, and enteropathic arthritis associated with Crohn’s disease or ulcerative colitis. They have been classified by the ASAS group (ASsessment in Ankylosing Spondylitis) into axial spondyloarthritis and peripheral spondyloarthritis. Common features include the absence of autoantibodies, genetic predisposition, and clinical aspects such as axial joint involvement, peripheral manifestations, and extra-articular involvement. However, the pathogenic mechanisms remain complex and incompletely elucidated, despite the fact that the specialized literature has described several pathways that act in synergy: genetic predisposition, environmental factors (infections and mechanical stress), or innate and acquired immune mechanisms. Finally, an inflammatory response is triggered by the recruitment of a large number of inflammatory cells and the release of innate cytokines in the affected areas: joints or periarticular or extraarticular tissues. The current article aims to update and systematize the knowledge accumulated so far on this topic, focusing on the mechanisms that have been involved in the onset, progression, and severity of ankylosing spondylitis.

Multisource energy harvesting using (Ba,Ca)(Zr,Ti)O3 oscillating under temperature gradient

AbstractThe concept of multisource energy harvesting has attracted attention in order to harvest multiple types of energy in a single material. In this work, Pb‐free (Ba,Ca)(Zr,Ti)O3 (BCZT) ceramics were used to investigate a combination of piezoelectric and pyroelectric energy harvesting behavior. The temperature dependence of the permittivity and the pyroelectric coefficient was measured, and the pyroelectric properties of BCZT were expected to improve near its orthorhombic–tetragonal phase transition temperature TO–T (∼40°C). The output voltage and current were measured using a BCZT plate, where the BCZT was oscillated under a temperature gradient to apply mechanical stress and temperature fluctuation simultaneously. The measured output voltage from the combined piezo‐ and pyroelectric contributions at a frequency of 2 Hz and with a load resistance of 10 MΩ was 1.4 times higher than the sole piezoelectric output voltage. The resulting combined output voltage was confirmed by finite element simulation.

DDEL-10. MICROBUBBLE-ENHANCED FOCUSED ULTRASOUND REGULATES THE ENRICHMENT OF INFLAMMATORY PATHWAYS IN THE BLOOD-BRAIN BARRIER AND IMPROVES CAR T CELL ACCUMULATION IN GLIOMAS

Abstract A major challenge to brain cancer immunotherapy is posed by the rate-limiting obstacles to the systemic delivery of cytotoxic T cells, such as chimeric antigen receptor (CAR) T cells, in brain tumors posed by the blood brain barrier (BBB). Although the BBB can be bypassed by direct infusion of CAR-T cells in brain tumors, these approaches offer only short-term benefits, since they cannot affect distant tumor cell infiltrations, as evidenced by tumor relapse. Circulating microbubbles (MB) upon ultrasound (US) exposure (sonication) can exert mechanical stress in brain vessels to trigger a range of responses, including local increase in the BBB permeability and activation of inflammatory signaling and phenotypes. We hypothesize that ultrasound frequency tuned at MB resonance inside brain capillaries can transiently modulate the BBB signaling and function to improve CAR-T cell trafficking in glioma tumors. RNAseq and immunostaining of protein expression reveal that at frequencies just above microbubble resonance inside vessels (1.5MHz for 2µm MB), where maximum vessel wall shear stress is observed, there is a marked enrichment of inflammatory markers in the endothelial cells of brain vessels, including P-selectin and ICAM-1. Consistent with these findings, we observed that under high frequency excitation (1.5MHz), there is a 5-fold increase in the accumulation of EGFRvIII CAR-T cells in orthotopic EGFRvIII murine glioma tumors as compared not sonicated controls. We also found that over 85% of the tumor-infiltrating CAR-T cells express PSGL-1 and LFA-1 receptors, which interact with P-selectin and ICAM-1 to facilitate T cell extravasation. Together, these findings demonstrate that tuning the US frequency can improve CAR-T cell trafficking, potentially through upregulation of cell adhesion molecules in the glioma tumor microenvironment, and further support the functional relevance and potential clinical significance of the observed immuno-mechano-biological changes.

Mitigating Mechanical Stress by the Hierarchical Crystalline Domain for High-Energy P2/O3 Biphasic Cathode Materials.

Sodium-ion batteries (SIBs) have captured widespread attention for grid-scale energy storage owing to the wide distribution and low cost of sodium resources. Delivery of high energy density with stable retention remains a challenge in developing cathode candidates for rechargeable SIBs. Inspired by the concept of "cationic potential", here, we present a hierarchical crystalline domain in hexagonal particles with target chemical composition (Na0.8Li0.03Mg0.05Ni0.28Fe0.05Mn0.54Ti0.05O2) from the inner bulk O3 phase (71.1 wt %) to the outer P2-type shell (28.9 wt %) of the structure. Benefiting from the mitigated mechanical stress of the predominant bulk O3 phase under the protection of the surficial P2 crystalline domain at the microscale during Na+ (de)intercalation, the brittle fracture, plastic yielding, and structural damage of the bulk O3 phase are effectively prohibited during battery cycling, thereby achieving good structural integrity. As a consequence, the biphasic P2/O3-Na0.8Li0.03Mg0.05Ni0.28Fe0.05Mn0.54Ti0.05O2 material exhibits satisfactory electrochemical properties, with a high energy density of 506 Wh kg-1 and good capacity retention of 85.5% over 200 cycles. This work highlights the importance of tailoring the crystalline domain to mitigate the reaction-induced stress and particle fracture of layered biphasic cathode materials for high-energy SIBs.

Protein phosphatase-1 regulates the binding of filamin C to FILIP1 in cultured skeletal muscle cells under mechanical stress

The actin-binding protein filamin c (FLNc) is a key mediator in the response of skeletal muscle cells to mechanical stress. In addition to its function as a structural scaffold, FLNc acts as a signaling adaptor which is phosphorylated at S2234 in its mechanosensitive domain 20 (d20) through AKT. Here, we discovered a strong dephosphorylation of FLNc-pS2234 in cultured skeletal myotubes under acute mechanical stress, despite high AKT activity. We found that all three protein phosphatase 1 (PP1) isoforms are part of the FLNc d18-21 interactome. Enzymatic assays demonstrate that PP1 efficiently dephosphorylates FLNc-pS2234 and in vitro and in cells upon PP1 activation using specific modulators. FLNc-pS2234 dephosphorylation promotes the interaction with FILIP1, a mediator for filamin degradation. Altogether, we present a model in which dephosphorylation of FLNc d20 by the dominant action of PP1c prevails over AKT activity to promote the binding of the filamin degradation-inducing factor FILIP1 during acute mechanical stress.

High-Strength, Self-Healing Copolymers of Acrylamide and Acrylic Acid with Co(II), Ni(II), and Cu(II) Complexes of 4′-Phenyl-2,2′:6′,2″-terpyridine: Preparation, Structure, Properties, and Autonomous and pH-Triggered Healing

The utilization of self-healing polymers is a promising way of solving problems associated with the wear and tear of polymer products, such as those caused by mechanical stress or environmental factors. In this study, a series of novel self-healing, high-strength copolymers of acrylamide, acrylic acid, and novel acrylic complexes of 4′-phenyl-2,2′:6′,2″-terpyridine [Co(II), Ni(II), and Cu(II)] was prepared. A systematic study of the composition and properties of the obtained polymers was carried out using a variety of physicochemical techniques (elemental analysis, gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), ultraviolet-visible spectroscopy (UV-vis), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), confocal laser scanning microscopy (CLSM), and tensile testing). All metallopolymer samples exhibit autonomous intrinsic healing along with maintaining high tensile strength values (for some samples, the initial tensile strength exceeded 100 MPa). The best values of healing efficiency are possessed by metallopolymers with a nickel complex (up to 83%), which is most likely due to the highest lability of the metal–heteroatom coordination bonds. The example of this system shows the ability to re-heal with negligible deterioration of the mechanical properties. The possibility of tuning the mechanical properties of self-healing films through the use of different metal ions has been demonstrated.

Ensemble Pretrained Convolutional Neural Networks for the Classification of Insulator Surface Conditions

Overhead transmission line insulators are non-conductive materials that separate conductors from grounded transmission towers. Once in operation, they frequently experience environmental pollution and electrical or mechanical stress. Since adverse operational conditions can lead to insulation failure, regular inspections are essential to prevent power outages. To this end, this paper proposes a novel technique based on deep convolutional neural networks (CNNs) to classify high-voltage insulator surface conditions based on their image. Successful applications of CNNs in computer vision have led to several pretrained architectures for image classification. To use these pretrained models, a practitioner typically fine-tunes and selects one final model via a model selection stage and discards all other models. In contrast with many existing studies that use such a “winner-takes-all” approach, here, we identify the best subset of seven popular pretrained CNN architectures that are combined by soft voting to form an ensemble classifier. From a machine learning (ML) perspective, this focus is warranted because the convolutional base of each pretrained architecture operates as a feature extractor and an ensemble of them works as a combination of various feature extraction rules. Our numerical experiments demonstrate the advantage of the identified ensemble model to individual pretrained architectures.

Hidden length lets collagen buffer mechanical and chemical stress

Hidden length lets collagen buffer mechanical and chemical stress

Preparation and optimization of La0.6Sr0.4Fe1-yCoyO3-δ cathodes for intermediate temperature solid oxide fuel cells

It is shown in this work that a synthetic route based on the auto-combustion of an ethylene glycol-metal nitrate polymerized gel precursor can be efficiently used to easily produce a range of La0.6Sr0.4Fe1-yCoyO3-δ nanopowders at moderate temperatures. We have been able to determine on air-sintered samples the effect of sintering temperature on the microstructure. At sintering temperatures as low as 1100 to1200 °C, grains are well defined with a uniform round spherical morphology and have a homogeneous sub-micrometer size distribution showing a highly densified microstructure. The electronic conductivity and thermal expansion coefficients (TEC) of sintered LSFC samples have been determined according to the variation of Fe/Co composition. Both measures clearly increase with the Co content. These materials also must exhibit chemical stability with electrolytes, most commonly used for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this way, the material as obtained is optimized in terms of chemical homogeneity and good stoichiometric control, microstructural characteristics of sintered samples, and finally the adequate Cobalt content to avoid high TEC mismatch with other components of the SOFC. This is a crucial issue as it causes an important thermo¬mechanical stress; promote extensive microcraking and significant performance degradation. Finally, these cathodes must exhibit acceptable electrochemical parameters for use in IT-SOFC.

Vitreous tissue cryopreservation using a blood vessel model and cryomacroscopy for scale-up studies: Observations and mathematical modeling

Successful long-term cryobanking of multicellular tissues and organs at deep subzero temperatures calls for the avoidance of ice cryoinjury by reliance upon ice-free cryopreservation techniques. However, the quality of the cryopreserved material is the direct result of its ability to survive a host of harmful mechanisms, chief among which is overcoming the trifecta effects of ice crystallization, toxicity, and mechanical stress. This study aims at exploring improved conditions to scale-up ice-free cryopreservation by combining DP6 as a base cryoprotective agent (CPA) solution with an array of synthetic ice modulators (SIMs). This study is conducted by integrating cryomacroscopy techniques, thermal modeling, solid mechanics analysis, and viability and contractility investigation to correlate physical effects, thermal outcomes, and cryobiology results. As an extension of previous work, this study aims at scale-up of established baseline blood vessel models, while comparing the relative toxicity and vitreous stability of 4 ml and 10 ml samples of DP6 containing either sucrose as a SIM, or the commercial synthetic ice blockers (X1000 and Z1000). Using that established protocol, the addition and removal of DP6+0.6M sucrose and DP6 + 1% X1000 + 1% Z1000 were both well tolerated in rabbit carotid and pig femoral artery models, when assessed for metabolic recovery and contractility. Using cryomacroscopy, it was demonstrated that DP6 + 0.6M sucrose provided a stable vitrification medium under marginal cooling and warming conditions that resulted in >50% survival rate. By contrast, DP6 + 1% X1000 + 1% Z1000 was subject to visible ice formation during cooling under the same thermal conditions, resulting in a significantly lower recovery of ∼20%. Thermal modeling is used in this study to verify the actual cooling and rewarming rates in the specimens, while thermomechanics analysis is used to explain why fractures were observed using cryomacroscopy when the specimens were contained in glass vials but not in plastic vials.

Influence of natural hyoid bone position and surgical repositioning on upper airway patency: A computational finite element modeling study.

A validated finite element model of the rabbit UA was advanced and used to simulate changes in BHP and SHR, alone and in combination. The hyoid was displaced in cranial, caudal, anterior, anterior-cranial and anterior-caudal directions from 1-4mm. Model outcomes included UA collapsibility, measured using closing pressure (Pclose), cross-sectional area (CSA) and soft tissue mechanics (displacement, stress and strain). Graded BHP increments increased Pclose for all directions, and up to 29-43% at 4mm (relative to the original BHP). Anterior-based SHR decreased Pclose (~-115% at 4mm) and increased ΔCSA (~+35% at 4mm). Cranial SHR decreased ΔPclose (-29%), minimally affecting CSA. Caudal SHR increased ΔPclose (+27%) and decreased ΔCSA (-7%). Anterior-cranial and anterior-caudal SHR produced the highest stresses and strains. SHR effects on UA outcomes were dependent on BHP, with more caudal BHPs leading to less effective surgeries. BHP (phenotype) and SHR both alter UA outcomes, with effects dependent on hyoid displacement direction and magnitude. BHP influences the effectiveness of SHR in reducing UA collapsibility. These findings provide further insights into the hyoid's role in UA patency and suggest that considering the hyoid's baseline position and surgical repositioning direction/increment may help improve hyoid surgeries for OSA treatment.

Ionic polymer-metal composite (IPMC) as a flexible capacitor: an experimental study

Abstract In recent years, significant research has been directed towards the development of energy storage devices that are thin, lightweight, and flexible, catering to the diverse demands of modern smart electronics. This study investigates the remarkable adaptability of ionic polymer metal composite (IPMC) capacitors when subjected to bending conditions. Under investigation was the capacitor’s functionality within a broad spectrum of bending angles, ranging from 0 ∘ to 100 ∘ . The study aims to reveal the capacitor’s response and stability across this expansive curvature range, providing insights into its potential applications in flexible and dynamic systems. The flexibility of the supercapacitor allows it to bend or fold up to 180 ∘ without experiencing permanent mechanical deformation. The calculated specific capacitance values obtained by bending the cell at angles of 0, 40, 70, and 100 ∘ are found to be 4.3, 6.4, 8.2, and 8.4 mF g−1 respectively. The result displayed the IPMC capacitor exhibited notable resilience under varying bending angles, affirming its capacity to maintain operational integrity despite significant mechanical stress. Through a systematic exploration of bending conditions, this research unveils the capacitor’s ability to flexibly conform to various bending angles. This adaptability is particularly significant for applications where traditional rigid capacitors may be impractical or inefficient.

Ultrasonic-assisted radial jet reattachment atomizer

Ultrasonic atomization, a powerful method using high-frequency sound waves, has gained notable significance across diverse industries due to its capacity to disintegrate liquids into very fine droplets. The use of ultrasonic vibrations for spray formation can effectively address the challenges associated with conventional methods, including the requirement for high temperatures and high-pressure fluids. Compared to conventional methods, ultrasonic atomizers can deliver a spray with lower velocity, operate at lower temperatures, produce smaller particle sizes, achieve high evaporation rates, and impose low mechanical stress. The radial jet reattachment (RJR) nozzle is a unique design to modify a jet’s flow and improve its transport characteristics, especially in air drying and cooling processes. In this paper, a novel technology is utilized with the combination of an RJR nozzle and ultrasonic atomization to atomize most liquids. The corresponding atomization rate, mist droplet size distribution, and mist droplet velocity distribution, influenced by liquid properties, temperature change, transducer mesh pore size, and applied voltage have been investigated in this paper. The energy consumption ratios, defined as the ratio of thermal energy required to evaporate liquid divided by ultrasonic energy, are analyzed based on atomization rate and applied power, showing very promising results among atomizing methods. Furthermore, the results in terms of the droplet average diameter and mean velocity as well as the resultant volumetric flow rate under different operating conditions and for all working fluids considered have been correlated with the aid of non-dimensional parameters. In addition, certain potential applications based on the remarkable characteristics of the ultrasonic-assisted RJR atomizer such as misting liquids and spray drying are highlighted.

Innovations in Energy Through Nanomaterials Enhancing Solid-State Battery Safety and Efficacy

This paper explores the potential of Si-based nanomaterials to enhance the performance of lithium-ion batteries (LIBs), particularly for electric vehicles (EVs). Traditional graphite anodes limit the energy density and range of EVs, increasing the need to search for alternative materials like silicon, which offers a much higher theoretical specific capacity. However, silicon’s application has been challenged by significant volume changes during cycling, leading to mechanical stress and failure. The use of nanotechnology, especially silicon nanomaterials, offers promising solutions to these challenges. Silicon nanostructures, such as nanowires, exhibit enhanced mechanical properties, allowing them to withstand volumetric changes and maintain high capacity during cycling. This review delves into the chemo-physical properties of silicon, the challenges posed by silicon anodes (SAs), and the recent advancements in silicon nanomaterials. Additionally, it also discusses different approaches to enhancing the performance of Si-based anodes, as well as the difficulties that exist now and the directions that future research in this exciting area is headed.

Regulation of ferroptosis in osteoarthritis and osteoarthritic chondrocytes by typical MicroRNAs in chondrocytes

Osteoarthritis (OA) is a progressive degenerative disorder impacting bones and joints, worsened by chronic inflammation, immune dysregulation, mechanical stress, metabolic disturbances, and various other contributing factors. The complex interplay of cartilage damage, loss, and impaired repair mechanisms remains a critical and formidable aspect of OA pathogenesis. At the genetic level, multiple genes have been implicated in the modulation of chondrocyte metabolism, displaying both promotive and inhibitory roles. Recent research has increasingly focused on the influence of non-coding RNAs in the regulation of distinct cell types within bone tissue in OA. In particular, an expanding body of evidence highlights the regulatory roles of microRNAs in OA chondrocytes. This review aims to consolidate the most relevant microRNAs associated with OA chondrocytes, as identified in recent studies, and to elucidate their involvement in chondrocyte metabolic processes and ferroptosis. Furthermore, this study explores the complex regulatory interactions between long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) in OA, with an emphasis on microRNA-mediated mechanisms. Finally, critical gaps in the current research are identified, offering strategic insights to advance the understanding of OA pathophysiology and guide therapeutic developments in this field.

Сверхпроводниковая электромагнитная система ИТЭР. Статус изготовления и сборки на 2024 год

The electromagnetic system (EMS) is one of the most significant components of the International Thermonuclear Experimental Reactor (ITER). It establishes the machine’s ability to generate and control a fusion plasma with a current of up to 15 MA and a power of up to 500 MW within hundreds of seconds. ITER EMS is the largest superconductor magnet system that has ever been created with a stored energy of up to 50 GJ. It is a highly technological magnets using superconductors based on Nb3Sn and NbTi, which work at a temperature of 4-6 K with compulsory cooling by a flow of liquid and gaseous helium. The EMS coils are required to be operable at electrical voltages up to 20-30 kV, and mechanical stresses up to 500-600 MPa. The manufacturing of the coils and the associated superconducting current carrying system are now moving into the final stage of production. The most part of them has already been manufactured and delivered to the ITER toroidal magnetic coil chamber (Tokamak) installation site. This review briefly describes the design of ITER superconductor coils of all 4 types and gives the current status of their manufacturing and assembly.

Machine learning model to study effects of lightweight racket design on elbow and shoulder loading during tennis serve

Tennis is a famous sport in which players perform high-speed, repetitive movements that cause significant load to the shoulder and elbow joints, particularly during tennis serve. Further, the racket design also plays a key role in the efficiency of the player’s performance through the level of mechanical stress that it places on the player’s elbow joints. Therefore, analyzing the biomechanical impact of racket types on the load it renders on elbow and shoulder loading will help optimize the player’s performance and avoid the possibility of risk. However, there are limited studies that are related to the effect of differences in racket mass, balance, and inertia over joint force and moment during the phases of serve. To address this gap, this study employs a Machine Learning (ML)-based model to impact three types of racket such as head-light, even-balanced, and head-heavy, towards joint moments and forces in the shoulder, elbow, and wrist during tennis serves. The kinematic data was collected from eight tennis players, and the collected data was processed using a Long Short-Term Memory (LSTM) neural network to predict joint moments and forces based on racket parameters and segmental kinematics. The results have shown that racket design has an excellent impact on a player’s performance through its impact on shoulder and elbow joints. The head-light racket resulted in a shoulder adduction moment of 9.4 ± 0.8 Nm and a shoulder joint force of 130.2 ± 9.4 N during the acceleration phase, compared to the head-heavy racket, which generated a higher adduction moment of 11.3 ± 1.0 Nm and a shoulder force of 162.3 ± 11.4 N. The even-balanced racket showed intermediate values, with an adduction moment of 10.2 ± 0.9 Nm and a shoulder force of 142.5 ± 9.9 N.

Single-cell morphometrics reveals T-box gene-dependent patterns of epithelial tension in the Second Heart field

The vertebrate heart tube extends by progressive addition of epithelial second heart field (SHF) progenitor cells from the dorsal pericardial wall. The interplay between epithelial mechanics and genetic mechanisms during SHF deployment is unknown. Here, we present a quantitative single-cell morphometric analysis of SHF cells during heart tube extension, including force inference analysis of epithelial stress. Joint spatial Principal Component Analysis reveals that cell orientation and stress direction are the main parameters defining apical cell morphology and distinguishes cells adjacent to the arterial and venous poles. Cell shape and mechanical forces display a dynamic relationship during heart tube formation. Moreover, while the T-box transcription factor Tbx1 is necessary for cell orientation towards the arterial pole, activation of Tbx5 in the posterior SHF correlates with the establishment of epithelial stress and SHF deletion of Tbx5 relaxes the progenitor epithelium. Integrating findings from cell-scale feature patterning and mechanical stress provides new insights into cardiac morphogenesis.

Immune system activation and cognitive impairment in arterial hypertension.

Chronic arterial hypertension disrupts the integrity of the cerebral microvasculature, doubling the risk of age-related dementia. Despite sufficient antihypertensive therapy, in still a significant proportion of individuals blood pressure lowering alone does not preserve cognitive health. Accumulating evidence highlights the role of inflammatory mechanisms in the pathogenesis of hypertension. In this review, we introduce a temporal framework to explore how early immune system activation and interactions at neurovascular-immune interfaces pave the way to cognitive impairment. The overall paradigm suggests that pro-hypertensive stimuli induce mechanical stress and systemic inflammatory responses that shift peripheral and meningeal immune effector mechanisms towards a pro-inflammatory state. Neurovascular-immune interfaces in the brain include a dysfunctional blood-brain barrier, crossed by peripheral immune cells; the perivascular space, in which macrophages respond to cerebrospinal fluid- and blood-derived immune regulators; and the meningeal immune reservoir, particularly T cells. Immune responses at these interfaces bridge peripheral and neurovascular unit inflammation, directly contributing to impaired brain perfusion, clearance of toxic metabolites and synaptic function. We propose that deep immunophenotyping in biofluids together with advanced neuroimaging could aid in the translational determination of sequential immune and brain endotypes specific to arterial hypertension. This could close knowledge gaps on how and when immune system activation transits into neurovascular dysfunction and cognitive impairment. In the future, targeting specific immune mechanisms could prevent and halt hypertension disease progression before clinical symptoms arise, addressing the need for new interventions against one of the leading threats to cognitive health.

Predictive modeling of lithium-ion battery degradation: Incorporating SEI layer growth and mechanical stress factors

Predictive modeling of lithium-ion battery degradation: Incorporating SEI layer growth and mechanical stress factors