Fiber Rupture Research Articles

Preventive impact of probiotic supplements on heart injury and inflammatory indices in a rat model of myocardial infarction: histopathological and gene expression evaluation.

Although there is a bulk of evidence on the favorable effect of probiotics on the cardiac system, their role in the management of myocardial infarction is not clear. Three viable probiotic bacterial strains, namely Lactobacillus reuteri, Bifidobacterium longum, and Bifidobacterium lactis, were gavaged to the rats daily for 28 days prior to the induction of myocardial injury. Myocardial injury was induced by the use of isoproterenol (ISO) in the probiotics, control and sham groups. The heart tissues were catheterized to evaluate the histopathological parameters and measure the expression of genes related to inflammation. Treatment with ISO caused subendocardial necrosis and rupture of cardiac myofibrils. Pretreatment with probiotics reduced the size of myocardial infarction caused by ISO. Also, in the probiotic group, a relative decrease in the amount of tissue fibrosis and rupture of cardiomyocytes fibers was seen. Pretreatment with probiotics partially ameliorated myocardial necrosis, edema and leukocyte infiltration. Also, a remarkable decrease was detected in the expression of tissue proinflammatory genes in the pretreated group with probiotics. Thus, viable probiotic supplementation may ameliorate or prevent cardiac injury. Additional preclinical and clinical studies are required to clarify the impact of probiotics in the prevention and management of cardiovascular disease.

Damage and fracture studies of continuous flax fiber-reinforced composites 3D printed by in-nozzle impregnation additive manufacturing

Additive manufacturing (AM) of continuous yarn-reinforced biobased composites presents multi-functional properties and low environmental impact of this technology. Few studies focused on the mechanical damage mechanisms of continuous biobased composites obtained by AM processes, while it is a topic of high interest for the mastery of mechanical behaviors and optimization of the materials for high requirement applications. This study aims to assess the damage and fracture modes of continuous flax yarn-reinforced PLA manufactured by AM, with different yarn orientations. The additively manufactured biobased composites were characterized by tensile test, 3D microscopy and micro-tomography to link the process-structure-properties relationships regarding the damage and fracture modes. The results showed that the 0° manufactured composite had a significant enhancement of tensile properties compared to other configurations. The damage mechanism presented fiber rupture with polymer transverse cracks at 0°, while the 45° and 90°-oriented composites showed premature fiber/matrix interface debonding. This study aims to find the relationship between damage mechanisms, deposition strategy, and anisotropy of the additively manufactured long vegetal fibers-reinforced biobased composite materials. The results bring a new understanding of the anisotropy and defects in printed composite materials regarding their mechanical behaviors during damage.

Interfacial bond behavior of steel fibers embedded in manufactured sand-based ultra-high performance concrete

The interfacial bond region between matrix and fibers is a non-negligible weak link that can significantly affect the mechanical properties of manufactured sand-based ultra-high-performance concrete (UHPMC). This study investigates the interfacial bond characteristics between steel fiber-UHPMC matrix using single-fiber pullout tests. Four variable parameters were considered: manufactured sand (MS) replacement ratio, stone powder content, fiber embedment length, and steel fiber geometry. Additionally, the microstructure of the steel fiber-UHPMC matrix interface was evaluated using backscattered electron microscopy (BSEM) and scanning electron microscopy (SEM). The results indicate that two typical failure modes including fiber pullout slip failure (in straight and hooked-end fibers) and fiber rupture failure (in corrugated fibers) were observed. The analysis of interfacial evaluation indicators shows that increasing the MS replacement ratio from 25 % to 100 % results in a decreasing trend in peak load, peak tensile stress, and energy consumption. Peak bond strength decreases with increasing embedment length. With the increase in stone powder content, the peak load, peak bond stress, and energy consumption increase initially and then decrease. Additionally, the interfacial failure mechanisms between straight/hooked-end steel fibers and the UHPMC matrix were further elucidated through bond-slip behavior characterization and microstructure analysis. Finally, a design-oriented bond-slip model was developed to predict the interfacial pull-out behavior of steel fiber -UHPMC matrix, showing favorable agreement between predicted and test results. These findings contribute to understanding the interfacial pullout behavior of steel fibers-UHPMC matrix, providing data reference for the performance optimization of UHPMC.

Flexural fatigue behavior of ultra-high performance fiber reinforced concrete

Even though UHPFRC has been extensively utilized in infrastructures owing to its excellent mechanical properties, its fatigue behavior remains unclear because related research is very limited. In this study, the fatigue characteristics of UHPFRC were investigated using a four-point bending experiment. In this study, the fatigue characteristics of UHPFRC were investigated using a four-point bending experiment. To determine the fatigue load conditions, static tests were conducted at different loading speeds and ages before, during, and after the fatigue tests. The obtained mechanical properties exhibited a clear dependence on loading rate and age duration. Consequently, a loading frequency of 3 Hz, which is close to that experienced in real infrastructures, was employed in the fatigue tests. A linear S-N relation with a 0.87 fatigue endurance limit was obtained on a semi-logarithmic scale. Additionally, the fatigue life showed a close relationship with the initial cycle deformation. Correspondingly, threshold values of deformation indicators were proposed for predicting the occurrence of fatigue failure. Furthermore, a linear positive relationship was found between the density of multiple fine cracks and fatigue life, based on post-fatigue crack measurements using a microscope. The relatively narrow crack width compared to other cementitious composites demonstrated UHPFRC's superior resistance to corrosion factors. Consistent with the linear S-N relation, the structural degradation appears to be governed by a fiber slippage-to-pull mechanism, as no fiber rupture was observed.

Complement C3a/C3aR inhibition alleviates the formation of aortic aneurysm in Marfan syndrome mice

Mutations in fibrillin 1 (FBN1) is the main cause of Marfan syndrome (MFS) with thoracic aortic aneurysm (TAA) as the main complication. Activation of the complement system plays a key role in the formation of thoracic and abdominal aortic aneurysms. However, the role of the complement system in MFS-associated aortic aneurysms remains unclear. In this study, we observed increased levels of complement C3a and C5a in the plasma of MFS patients and mouse, and the increased deposition of the activated complement system product C3b/iC3b was also observed in the elastic fiber rupture zone of 3-month-old MFS mice. The expression of C3a receptor (C3aR) was increased in MFS aortas, and recombinant C3a promoted the expression of cytokines in macrophages. The administration of a C3aR antagonist (C3aRA) attenuated the development of thoracic aortic aneurysms in MFS mice. The increased inflammation response and matrix metalloproteinases activities were also attenuated by C3aRA treatment in MFS mice. Therefore, these findings indicate that the complement C3a/C3aR inhibition alleviates the formation of aortic aneurysm in Marfan syndrome mice.

Mechanism analysis on tensile fracture properties of heterogeneous BFLAC at cryogenic temperature: Experimental investigation and mesoscale simulation

This study aims to investigate the tensile failure behaviours and corresponding fracture mechanisms of basalt fiber reinforced lightweight-aggregate concrete (BFLAC) at various temperatures via a comprehensive cryogenic tests and mesoscale simulations, with a special focus on the quantitative effects of cryogenic temperature and fiber volume fraction. Firstly, Macro- and micro-scale split-tensile tests of BFLAC with fiber volume fractions of 0.0–0.3 % at 20∼-90 °C were conducted. Secondly, a two-steps sequentially thermo-mechanical coupled meso-scale analysis approach with explicit modelling of fibers and pore ice was developed to simulate the corresponding direct-tensile failures of BFLAC with more fiber volume fractions. The results show that as the temperature falls from 20 °C to −90 °C, the dominant action mechanism of basalt fibers changes from Mode-1 (pull-out of fibers) to Mode-2 (rupture of fibers) due to the ice formation and the interactions between meso-components. Tensile strengths of BFLAC present a significant low-temperature enhancing effect, with a maximum increase of 90 % for direct-tensile strength while 104 % for split-tensile strength. Besides, as the temperature drops, although a larger proportion of fibers are in a low bridging stress state and a smaller proportion reach yield stress for rupture, the average fiber stress increases and the utilization degree of fibers with more stresses transferred improves, which results in that the fiber reinforcement effect is strengthened. Finally, based on experimental and numerical results, the quantitative relationships between split-tensile and direct-tensile strengths at different cryogenic temperatures were given. The present research results can better understand the cryogenic mechanical properties of BFLAC, which have important reference value for its extensive promotions and applications in engineering structures exposed to extreme low-temperature environments.

TYPES OF TREATMENT AND FAILURE MODE OF CEMENTITIOUS MORTARS REINFORCED WITH SUGARCANE BAGASSE

The entire scientific community now agrees that sustainable development depends on environmentally friendly and renewable materials. Thus, all government policies are taking numerous steps to encourage research in this direction. The aim of the present work is to study the fracture mechanism of Sugarcane Bagasse (SCB) mortars as a function of the different treatments applied to the bagasse.To achieve this, two different types are applied toSCB. These were treatment in a sodium hydroxide solution and heat treatment at 200°C. Mortars reinforced with these different types of bagasse were then produced. The volume fractions of SCB used were 0%, 3% and 6%, giving M0 for reference mortar, MBr3 and MBr6 for mortars with untreated SCB reinforcement, MBt3 and MBt6 for mortars with heat-treated SCB reinforcement, MBc3 and MBc6 for mortars with sodium hydroxide-treated SCB reinforcement. Three-point bending tests at 28 days of age were carried out on specimens of dimensions 4×4×16cm3 obtained from the different formulations, to determine the flexural strengths. The fracture surfaces of the specimens were analyzed to understand the fracture mechanism as a function of the type of treatment applied to the SCB.The results of the studies show that all the formulations containing SCB have a flexural strength greater than that of the control mortar, with the highest strength found in the MBt6 mortar. Analysis of the fracture surfaces shows that mortars containing untreated and heat-treated SCB exhibit failure by ravelling. However, mortars containing SCB treated with sodium hydroxide break by fiber rupture.

Dynamic responses and damage/element composition analysis of thermoplastic polyamide reinforced epoxy composites exposed to HCI environment

AbstractThe present study aimed to examine how the corrosive environment affected the low‐velocity impact (LVI) characteristics and damage mechanisms of thermoplastic polyamide fiber‐reinforced polymer (PFRP) composites. In this regard, composite specimens were subjected to corrosive environment containing 10 wt.% diluted HCl for one week and one month before LVI tests. To investigate the hostile effects of the corrosive environment on the composites, scanning electron microscope (SEM) coupled with energy‐dispersive X‐ray system (EDX) analyses were carried out, and thus variations in the elemental composition and damage mechanisms for the composites were determined. According to the examinations, it was discovered that the degradation in LVI responses, such as contact stiffness, bending stiffness, and peak force, increased with longer aging time, as expected. Furthermore, when the aging effect was assessed based on absorbed energy, the specimens exposed to a corrosive environment for one month exhibited the highest energy absorption compared to the control and 1‐week‐immersed ones. The degrading effect of the HCI environment appeared as higher damage severity on the composites, which was also detected from the SEM images. According to the SEM analyses, matrix cracks, corrosion pits, and local surface imperfections caused by ion exchange are detected in 1‐week‐immersed specimens, while more serious damage mechanisms such as fiber breakage and fiber pull‐out are noted in specimens exposed to corrosive environment for 1 month. Furthermore, approximately 6.33 wt.% CI was identified in the composites after 1 month of aging, which was associated with the hydrolysis triggered by rise in the composite's damage severity.Highlights Aging effects in mechanical properties of PFRP composites were investigated LVI tests were conducted to determine dynamic responses of aged composites Longer aging time led to more severe damages such fiber rupture, delamination etc. PFRP composites absorbed at least 68% of impact energy.

Design of an explicit crack bridging constitutive model for engineered cementitious composites using polyvinyl alcohol (PVA) or polyethylene (PE) fiber

This paper aims to establish an explicit crack bridging model that can link engineered cementitious composites (ECC) behavior from single fiber to single crack scale, which is great of designing ECC featuring pseudo tensile strain hardening and multiple cracks expanding by tailoring microstructure and materials selection. In this study, fiber bridging stress was divided into three parts including fiber bridging stress with no rupture, fiber debonding fracture stress, and fiber pullout fracture stress. Subsequently, the fundamental crack bridging model was emerged when fiber bridging stress with no rupture subtracted from the fiber rupture stress in debonding and pullout stage. Moreover, two-way pullout and Cook-Gordon effect were also considered to establish the complete model. It was found that the two-way pullout situation of polyvinyl alcohol (PVA) fiber has a significant influence on the crack opening width due to its slip hardening property, while the Cook-Gordon effect presents a faint crack width increment for PVA-ECC. However, the Cook-Gordon effect makes a significant contribution to the crack opening width of the composite produced by polyethylene (PE). This building intelligible model presents a better prediction for ECC through the comparison of experimental data or real average crack width in previous models, thus confirming the validity of this model.

Qi Lang formula relieves constipation via targeting SCF/c-kit signaling pathway: An integrated study of network pharmacology and experimental validation

BackgroundConstipation is one of the chronic gastrointestinal functional diseases that affects the quality of life. While Qi Lang Formula (QLF) has demonstrated effectiveness in alleviating constipation symptoms, its precise mechanism remains elusive. MethodsQLF was analyzed using UPLC-MS/MS. Targets for QLF were collected from SwissADME, Herb, ITCM databases, and constipation-related targets from scRNA-seq and Genecards databases. Overlapping targets suggested potential QLF therapy targets for constipation. Enrichment analysis used the KOBAS database. A "drug-ingredient-target" network was constructed with Cytoscape, and AutoDock verified active ingredient binding. H&E staining assessed colonic mucosa changes, TEM examined ICC structural changes. ELISA measured neurotransmitter levels, and Western blot verified QLF's effect on target proteins. ICC proliferation was observed through immunofluorescence. ResultsWe identified 89 targets of QLF associated with ICC-related constipation, with c-Kit emerging as the pivotal target. Molecular docking studies revealed that Atractylenolide Ⅲ, Apigenin, Formononetin, Isorhamnetin, Naringenin, and Ononin exhibited strong binding affinities for the c-Kit structural domain. QLF significantly enhanced first stool passage time, fecal frequency, fecal moisture content, and intestinal propulsion rate. Further analysis unveiled that QLF not only restored neurotransmitter levels but also mitigated colon muscular fiber ruptures. ICC ultrastructure exhibited partial recovery, while Western blot confirmed upregulated c-Kit expression and downstream targets. Immunofluorescence results indicated ICC proliferation post QLF treatment in rat colon. ConclusionOur findings suggest that QLF may promote ICC proliferation by targeting SCF/c-Kit and its downstream signaling pathway, thereby regulating intestinal motility.

Dynamic response of ultra-high performance engineered cementitious composites (UHP-ECC) under low-velocity impact: Effect of waste rubber incorporation and low temperatures

This study aims to explore the dynamic response of ultra-high performance engineered cementitious composites (UHP-ECC) incorporating waste crumb rubber (CR) at various temperatures, focusing on its potential to enhance the resilience and sustainability of civil infrastructures against low-velocity impacts. To date, the impact behaviour of UHP-ECC under low temperatures has rarely been explored. Firstly, natural river sand and waste tyre CR was utilized to prepare the UHP-ECC. Then, a series of mechanical tests, including compression test, flexural test and uniaxial tensile test were carried out to investigate the static mechanical properties of rubberised UHP-ECCs. In addition, the effects of different waste CR incorporations (0%, 5%, 10%, and 15%) and various temperatures (25 °C, −5 °C, −30 °C, −50 °C, −100 °C and −196 °C) were comprehensively investigated by low-velocity impact tests with constant impact energy. Lastly, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) model was introduced to evaluate the overall performance of UHP-ECC. It was found that the use of river sand and CR significantly enhanced the tensile ductility and impact toughness of UHP-ECC. Impact energy primarily dissipates through damage such as matrix crack initiation, propagation, and fibre pull-out/rupture within the specimen. Adding CR notably decreased stress fluctuations during impact at room temperature, facilitating steady state energy absorption. Moreover, the time to reach peak impact force decreased with decreasing temperature across all UHP-ECC groups. At room temperature during impact process, fibre failure mode is dominated by pull-out failure, while lower temperatures lead to increased fibre rupture at the cracking surface. In low-temperature conditions, the impact response of rubberised UHP-ECC necessitates a comprehensive consideration of the synergistic effects, including material contraction, fibre bridging capacity, rubber phase transition, and water freezing.

Dan-shen Yin promotes bile acid metabolism and excretion to prevent atherosclerosis via activating FXR/BSEP signaling pathway

Ethnopharmacological relevanceDan-shen Yin (DSY), a traditional prescription, has been demonstrated to be effective in decreasing hyperlipidemia and preventing atherosclerosis (AS), but its mechanism remains unknown. We hypothesized that DSY activates farnesoid X receptor (FXR) to promote bile acid metabolism and excretion, thereby alleviating AS. Aim of the studyThis study was designed to explore whether DSY reduces liver lipid accumulation and prevents AS by activating FXR and increasing cholesterol metabolism and bile acid excretion. Materials and methodsThe comprehensive chemical characterization of DSY was analyzed by UHPLC-MS/MS. The AS models of ApoE−/− mice and SD rats was established by high-fat diet and high-fat diet combined with intraperitoneal injection of vitamin D3, respectively. The aortic plaque and pathological changes were used to evaluate AS. Lipid levels, H&E staining and oil red O staining were used to evaluate liver lipid accumulation. The cholesterol metabolism and bile acid excretion were evaluated by enzyme-linked immunosorbent assay, UPLC-QQQ/MS. In vitro, the lipid and FXR/bile salt export pump (BSEP) levels were evaluated by oil red O staining, real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting. ResultsA total of 36 ingredients in DSY were identified by UPLC-MS/MS analysis. In vivo, high-dose DSY significantly inhibited aortic intimal thickening, improved arrangement disorder, tortuosity, and rupture of elastic fibers, decreased lipid levels, and reduced the number of fat vacuoles and lipid droplets in liver tissue in SD rats and ApoE−/− mice. Further studies found that high-dose DSY significantly reduced liver lipid and total bile acids levels, increased liver ursodeoxycholic acid (UDCA) and other non-conjugated bile acids levels, increased fecal total cholesterol (TC) levels, and augmented FXR, BSEP, cholesterol 7-alpha hydroxylase (CYP7A1), ATP binding cassette subfamily G5/G8 (ABCG5/8) expression levels, while decreasing ASBT expression levels. In vitro studies showed that DSY significantly reduced TC and TG levels, as well as lipid droplets, while also increasing the expression of ABCG5/8, FXR, and BSEP in both HepG2 and Nr1h4 knockdown HepG2 cells. ConclusionThis study demonstrated that DSY promotes bile acid metabolism and excretion to prevent AS by activating FXR. For the prevent of AS and drug discovery provided experimental basis.

Flexural behavior evaluation of concrete filled small-angle winded GFRP tube columns

In harsh environments such as ocean engineering, reinforced concrete structures suffer from severe corrosion, and concrete-filled fiber-reinforced polymer tubes (CFFT) have been widely used as a substitute for them. In this paper, extremely small-angle GFRP tubes are manufactured using the winding process and the flexural behavior of ±55° and ±15° angle-ply GFRP tube columns is investigated. The effects of the winding angle on the flexural behavior of CFFT were studied by experiment. The experimental results showed that the failure modes of CFFT were dominated by fiber rupture, slip between concrete and GFRP tube, and concrete crushing. Reducing the winding angle and filling concrete can effectively improve the ultimate flexural load by 117.25%, and 182.01%, respectively. Furthermore, a numerical model was established to predict the flexural behavior of CFFT, the Concrete Damaged Plasticity model was used to simulate the behavior of the concrete, and the Hashin failure criterion was used for the GFRP tube. The predicted failure modes and load-displacement curves were in good agreement with the experimental results. Parametric analysis showed that increasing the GFRP tube thickness can improve the ultimate flexural load by 62.72% and increasing concrete strength changes the failure mode of CFFT from GFRP tube rupture to concrete damage.

HTD4010 attenuates myocardial injury in mice with septic cardiomyopathy by promoting autophagy via the AMPK/mTOR signaling pathway

To investigate the protective effects of HTD4010 against lipopolysaccharide (LPS)-induced septic cardiomyopathy (SCM) in mice and explore the mechanisms mediating its effect. Forty-five male ICR mice were randomized equally into control group, LPS (10 mg/kg) group, and LPS+HTD4010 group (in which 2.5 mg/kg HTD4010 was injected subcutaneously at 1 h and 6 h after LPS injection). Cardiac function of the mice was evaluated by ultrasound, and pathological changes in the myocardial tissues were observed with HE staining. The levels of IL-6 and TNF-α in serum and myocardial tissues were detected using ELISA, and apoptosis of the cardiomyocytes was detected with TUNEL staining. The expression levels of the key proteins associated with apoptosis, autophagy and the AMPK/mTOR pathway in the myocardial tissues were detected using Western blotting. The ultrastructural changes of cardiac myocardial mitochondria was observed with transmission electron microscopy. LPS exposure caused severe myocardial damage in mice, characterized by myocardial fiber rupture, structural disorder, inflammatory cell infiltration, and mitochondrial damage. The LPS-treated mice exhibited significantly decreased cardiac LVEF and FS values, elevated IL-6 and TNF-αlevels in serum and myocardial tissue, and an increased myocardial cell apoptosis rate with enhanced expressions of Bax, p-62 and p-mTOR and lowered expressions of Bcl-2, LC3 II/I, Beclin-1 and p-AMPK (P < 0.05 or 0.01). Treatment of the septic mice with HTD4010 significantly alleviated myocardial damage, increased LVEF and FS values, reduced IL-6 and TNF-α levels in serum and myocardial tissue, decreased cardiomyocyte apoptosis, lowered myocardial expressions of Bax, p-62 and p-mTOR, and increased Bcl-2, LC3 II/I, Beclin-1 and p-AMPK expressions (P < 0.05 or 0.01). HTD4010 can attenuate myocardial injury in SCM mice possibly by promoting autophagy via modulating the AMPK/mTOR signaling pathway.

Assessing the stress-transfer capability of mineral impregnated PBO yarns in a limestone calcined clay cement-based (LC3) matrix

Technical textiles made of poly(p-phenylene-2,6-benzobisoxazole) (PBO) represent attractive candidates for strengthening and repairing damaged concrete and masonry structures, due to the outstanding durability and mechanical performance of PBO fibres. Similarly to their aramid counterparts, PBO fibres have proved very effective against dynamic and impact loading. In this contribution, the pull-out behaviour of PBO multifilament yarns embedded into a blended cement-based matrix is investigated, with particular reference to its stress-transfer capacity. In addition to the as-received PBO yarns, impregnation with a cement-based suspension, which can fully preserve the inorganic nature of the composite system, is also evaluated. Experimental results are presented and interpreted using a one-dimensional mechanical model. The findings indicate that mineral impregnation of the yarns provides a 40% increase in the stress-transfer capacity with the matrix, corresponding to a halving of the anchoring length. These performance gains are also supported by a transition in the failure mechanism which shifts from friction-based pull-out to fibre rupture.

Electron Beam-Modified Collagen Type I Fibers: Synthesis and Characterization of Mechanical Response.

Ten MeV electron beam treatment facilitates a biomimetic introduction of cross-links in collagenous biopolymer systems, modifying their viscoelastic properties, mechanical stability, and swelling behavior. For reconstituted collagen type I fibers, electron-induced cross-linking opens up new perspectives regarding future biomedical applications in terms of tissue and ligament engineering. We demonstrate how electron irradiation affects stiffness both in low-strain regimes and in postyield regimes of biocompatible reconstituted rat tail collagen type I fibers. Stress-strain tests show a dose-dependent increase in modulus in the nonlinear elastic response, indicating a central role of induced cross-links in mechanical stability. Environmental scanning electron microscopy after fiber rupture reveals aligned distributed collagen fibril domains under the fiber surface for as-prepared fibers, accompanied by a ductile fracture behavior, whereas, in tensile tests imaged by light microscopy after 10 MeV electron treatment, isotropic network topologies are observed until the occurrence of a brittle type of rupture. Based on the biomimicry of the process, these findings might pave the way for a novel type of synthesis of tailored tendon or ligament substitutes.

Decompression sickness-induced skeletal muscle injury: an animal model and pathological analysis.

The primary objective of this investigation is to establish an animal model that accurately represents skeletal muscle injury as a consequence of decompression sickness. Additionally, this study aims to delineate the potential mechanisms underlying the development and progression of skeletal muscle damage associated with decompression sickness. (1) In this research, rats were utilized as experimental models and subjected to 600 kPa pressure in an air medium for a duration of 60 min, followed by decompression at a consistent rate of 1.5 min to reach atmospheric pressure in order to establish an animal model for decompression injury. Assessment of decompression injury involved the observation of general symptoms and signs, as well as histopathological examination of lung tissue to determine the extent of damage in the pulmonary system of rats. (2) Building on the rat decompression injury model, we conducted pathological and serological examinations to assess the status of rat skeletal muscle. Additionally, we investigated the signaling mechanism of the TLR9-MyD88 pathway in mediating alterations in rat skeletal muscle resulting from decompression injury, and evaluated the effects of decompression injury on apoptosis in rat skeletal muscle. Repeated decompression induces significant damage to skeletal muscle tissue, characterized by edema, fiber rupture, and atrophy. This process also leads to a transient elevation in creatine kinase (CK-MM) levels in rat serum, as well as an upregulation of proteins such as TLR9, MyD88, p38, and ERK in rat skeletal muscle tissue. Furthermore, repeated decompression results in a temporary increase in the transcription levels of Atrogen-1mRNA and MuRF-1mRNA in rat skeletal muscle tissue. The decompression protocol applied in this study successfully induced decompression sickness in a rat model, leading to skeletal muscle damage that was consistent with the expected pathology of decompression injury. Despite the initial injury, the rats showed evidence of adaptation following prolonged exposure to decompression conditions.

Characterization and ballistic performance of hybrid jute and aramid reinforcing graphite nanoplatelets in high-density polyethylene nanocomposites

Hybrid nanocomposites have emerged as a promising solution for engineering applications associated with reduced costs and weight aiming to enhance performance in special areas such as ballistic protection. This study delves into the development of hybrid nanocomposites featuring a high-density polyethylene matrix modified with graphite nanoplatelets and reinforced by aramid and jute fabrics. The incorporation of GNP significantly influences the crystalline structure of the GNP/HDPE matrix, as evidenced by Raman and X-ray diffraction analyses. Furthermore, it assumes an important role in modifying the crystallization and glass transition temperatures (Tc and Tg) and influencing the dynamic mechanical behavior. Specifically, it increases viscoelastic stiffness, raises the storage modulus by more than 30 %, and reduces the tanδ value. In addition, replacing 5 layers of jute fabric with an equivalent number of aramid layers maintains comparable ballistic performance to a 20-layer aramid nanocomposite. This substitution yields a remarkable 659.41 J of absorbed energy and a limit velocity of 405.72 m/s. Additionally, a hybrid nanocomposite comprising 10 layers each of jute and aramid showcases impressive ballistic resistance against 9 mm caliber ammunition, achieving 419.84 J of absorbed energy and a limit velocity of 320.13 m/s. Scanning electron microscopy analysis exposes the intricate fracture mechanisms, encompassing phenomena such as crazing, GNP/HDPE fibrillation, fiber rupture, and debonding. These mechanisms are significant in the composite's energy absorption during a projectile impact. Moreover, a cost-benefit analysis underscores the potential of hybrid nanocomposites in ballistic protection by simultaneously reducing both helmet weight and cost in 7 % and 40 %, respectively.

Effects of Graphene Oxide Nanoparticles on Delamination in CFRP and Optimization Using Response Surface Modeling

AbstractCarbon fiber composites recently have captured the attention of many for their wide array of properties surpassing those of traditional metals. Carbon fiber‐reinforced plastic (CFRP) has several excellent properties like a high strength‐to‐weight ratio, better chemical resistance, and other strength characteristics. But one problem affecting the use of CFRP is its delamination. This occurs during drilling holes for various operations. It is a known fact that the aircraft industry is one such industry very much dependent on such drilling operations. Failures such as fiber rupture, surface irregularities, micro‐crack formation, and deformations around drilling regions are commonly encountered during the machining of CFRP composite. This research has studied the effects of graphene oxide nanoparticles on delamination in the drilling of CFRP composite. Carbon fiber is manufactured using a vacuum bag process. The optimum conditions for the drilling process are found by using response surface modeling (RSM) which leads to minimum delamination in CFRP fabricated.

Development of Methods to Obtain Grafts for the Anterior Abdominal Wall in Surgical Treatment of External Abdominal Hernias

INTRODUCTION: Currently, tissue engineering is one of the most promising fields of medicine dealing with search for solutions to the problems of creation of biocompatible structures capable of partial or complete replacement of organs or tissues of an organism. An advanced method of tissue engineering implies using an extracellular matrix (ECM) cleared from the cellular material. The main problem of obtaining an ECM consists in the difficulty of selecting a suitable decellularization method and exposure time.&#x0D; AIM: Development of a method for obtaining grafts for the anterior abdominal wall (AAW) and evaluation of the histological properties of the ECM to determine the optimal protocol for donor tissue decellularization providing a complete removal of cellular material without any significant damage to the scaffold.&#x0D; MATERIALS AND METHODS: The experiments were conducted on 10 White Flemish Giant male rabbits. All the animals were withdrawn from the experiment, after which, on autopsy, AAW grafts were obtained for evaluation of the decellularization properties of three detergents (alkaline solutions): 2% SDS (sodium dodecyl sulfate) solution, 2% CHAPS (zwitterionic surfactant, 3-[(3-cholamidopropyl)-dimethylammonio]-2-hydroxy-1-propansulfonate) solution, and 1% Triton-X 100 solution. The decellularization quality was controlled in histological examination.&#x0D; RESULTS: Morphological evaluation of tissue samples revealed that after decellularization of the material with 2% SDS solution and 2% CHAPS solution, the number of cells remaining in the preparations was comparable and significantly less (Me = 10 in a microscope field) than after treatment with 1% Triton-X 100 solution (Me = 45 in a microscope field). However, decellularization with 2% CHAPS solution led to fiber ruptures and tissue edema manifested by an increase in the distance between the fibers (Me = 163 µm).&#x0D; CONCLUSIONS: Decellularization of the anterior abdominal wall tissues with 2% SDS solution provides a sufficient cell elimination while preserving the fiber integrity and ECM structure. 2% CHAPS solution was comparable to 2% SDS solution in terms of the quality of cell elements removal, but its more aggressive effect on collagen fibers was noted (their multiple ruptures and a more pronounced edema). 1% Triton-X 100 solution appeared to be of low efficiency in elimination of cellular material, although it had a minimal effect on the integrity of ECM network.