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In vivo observations show that oxygen levels in tumours can fluctuate on fast and slow timescales. As a result, cancer cells can be periodically exposed to pathologically low oxygen levels; a phenomenon known as cyclic hypoxia. Yet, little is known about the response and adaptation of cancer cells to cyclic, rather than, constant hypoxia. Further, existing in vitro models of cyclic hypoxia fail to capture the complex and heterogeneous oxygen dynamics of tumours growing in vivo. Mathematical models can help to overcome current experimental limitations and, in so doing, offer new insights into the biology of tumour cyclic hypoxia by predicting cell responses to a wide range of cyclic dynamics. We develop an individual-based model to investigate how cell cycle progression and cell fate determination of cancer cells are altered following exposure to cyclic hypoxia. Our model can simulate standard in vitro experiments, such as clonogenic assays and cell cycle experiments, allowing for efficient screening of cell responses under a wide range of cyclic hypoxia conditions. Simulation results show that the same cell line can exhibit markedly different responses to cyclic hypoxia depending on the dynamics of the oxygen fluctuations. We also use our model to investigate the impact of changes to cell cycle checkpoint activation and damage repair on cell responses to cyclic hypoxia. Our simulations suggest that cyclic hypoxia can promote heterogeneity in cellular damage repair activity within vascular tumours. [ABSTRACT FROM AUTHOR]

In the past five years, the implementation of machine learning (ML) techniques has surged in civil engineering applications, particularly for optimizing and predicting solutions to various challenges. More robust prediction models may be produced by combining test data collected in the laboratory or field with ML. These models may be used to estimate the compressive strength of masonry or repair mortars, probable damage scenarios in buildings, concrete models, beams, and columns for determining the mechanical characteristics of materials, damage detection in civil structures, and so on. This comprehensive review aims to clarify the array of ML-based methods employed in civil engineering, specifically focusing on their efficacy in strengthening energy efficiency and cost-effectiveness. In combination with ML, the review explores corresponding soft computing methodologies such as fuzzy logic (FL) and design of experiments (DOE). A variety of case examples that highlight the versatility of these approaches, particularly in applications linked to structural reinforcement, enhance the story. The review navigates difficulties associated with the integration of soft computing in civil engineering and expands its scope to include emerging research directions. This synthesis of advanced artificial intelligence (AI) serves as a guide, providing new researchers with knowledge about a developing field. These methods could revolutionize the current situation by providing creative answers to complex problems that arise in civil structural applications.

Corneal injury and trauma present a significant challenge in terms of healing, as natural tissue repair leads to fibrosis and scar formation, which can have a detrimental impact on vision. Therefore, it is necessary to develop effective treatment methods that will reduce inflammation and promote tissue repair while maintaining the native transparency of tissue and vision. When applied to the skin, collagen can inhibit the progression of inflammation and facilitate the repair of damaged skin. Herein, we investigated the potential of collagen for the repair of corneal injuries, utilizing nanoscale dimensions that minimize ocular surface irritation. Electrospun collagen nanofibers (eCFs) retain the natural properties of collagen and have a large surface area and high porosity, rendering them highly suitable for mimicking the natural extracellular matrix (ECM) and providing a favorable microenvironment for cell growth. In vitro models of inflammation were constructed using human corneal epithelial cells (hCECs) and human corneal stromal fibroblasts (hCSFs). The addition of eCFs significantly inhibited lipopolysaccharide (LPS)-induced corneal inflammation. In vitro cell experiments and three-dimensional culture models were established to test the influence of eCFs on cell behavior as scaffolds. The eCFs promoted cell proliferation, migration, and stretching and are beneficial for maintaining a quiescent phenotype. Nanoscale collagen demonstrated superior wound-healing effects in animal models, promoting epithelial healing and maintaining transparency of the corneal stroma. In conclusion, eCFs considerably suppressed the production of LPS-induced inflammatory cytokines in vitro, while promoting the healing and repair of the corneal epithelium and inhibiting corneal stromal fibrosis. Thus, this type of collagen nanofiber has great potential in the biomedical field, providing a perspective for the optimization of clinical treatment strategies for corneal injuries. [ABSTRACT FROM AUTHOR]

This document provides a comprehensive overview of the integration of civil structural health monitoring and machine learning in the field of concrete structures. It discusses the importance of monitoring infrastructure condition and the challenges of manual inspection. The document highlights the increasing use of machine learning algorithms, such as computer vision methods, in optimizing maintenance and repairs. It presents case studies and applications of machine learning in civil engineering, including damage detection and load assessment. The document also emphasizes the challenges and limitations of using machine learning in this context and recommends further research and interdisciplinary collaboration. Additionally, it addresses ethical and privacy concerns, the importance of open data sharing, and aligning machine learning applications with sustainability efforts. The document includes a list of academic articles related to machine learning techniques in concrete structures, covering topics such as crack detection and structural health monitoring. It also compiles various studies and research papers on machine learning for structural health monitoring in concrete structures, exploring different methods and highlighting the potential of deep learning models and image processing techniques for crack detection. Overall, the document provides a comprehensive overview of the application of machine learning in the field of structural health monitoring for concrete structures. [Extracted from the article]

Objectives: The aim of this study was to investigate the molecular mechanism underlying odontoblast damage repair in dentin hypersensitivity (DH) and the role of Yes-associated protein (YAP) in this process. Methods: The DH model was constructed in Sprague-Dawley (SD) rats, and the in vivo expression of Piezo1, Integrin αvβ3, YAP, and dentin sialophosphoprotein (DSPP) was detected by immunohistochemistry. COMSOL Multiphysics software was used to simulate the dentinal tubule fluid flow velocity and corresponding fluid shear stress (FSS) on the odontoblast processes. MDPC-23 cells were cultured in vitro and loaded with a peristaltic pump for 1 hour at FSS values of 0.1, 0.3, 0.5, and 0.7 dyne/cm2. The expression of Piezo1, Integrin αvβ3, and YAP was detected by immunofluorescence. Verteporfin (a YAP-specific inhibitor) was utilised to confirm the effect of YAP on the expression of dentineogenesis-related protein under FSS. Results: The level and duration of external mechanical stimuli have an effect on the functional expression of odontoblasts. In DH, the harder the food that is chewed, the faster the flow of the dentinal tubule fluid and the greater the FSS on the odontoblast processes. The expression of Piezo1, Integrin αvβ3, and YAP can be promoted when the FSS is less than 0.3 dyne/cm2. After YAP inhibition, the DSPP protein expression level was reduced at 0.3 dyne/cm2 FSS. Conclusions: These results suggest that appropriate FSS can enhance the expression of odontoblast-related factors in odontoblasts via the Piezo1–Integrin αvβ3–YAP mechanotransduction pathway and the YAP appears to play an essential role in the response of odontoblasts to external mechanical stimuli.

A solid-state repair technique based on surface friction welding is investigated in depth to achieve excellent mechanical properties of damaged 7A52 aluminum alloy. The results show that the yield strength and tensile strength along the repair direction are 436 MPa and 502 MPa, respectively, at a rotational speed of 1400 rpm and a travel speed of 300 mm/min, which are about 157.9% and 129.7% of those before the defects were repaired, respectively, while the elongation is 17.2% compared to the base material. Perpendicular to the repair direction, the yield strength and tensile strength are 254 MPa and 432 MPa, which are 111.4% and 129.7% of those before the defects were repaired, respectively, while the elongation is 11.8% compared to the base material. The mechanical properties of the repaired areas are still improved compared to those of the defect-free sheets. On the one hand, this is attributed to the dynamic recrystallization of the nugget zone due to the thermo-mechanical coupling, resulting in the formation of a fine, equiaxed grain structure; on the other hand, the precipitated Mg2Si phase, which is incoherent within the base material, transforms into the Al12(Fe, Mn)3Si phase, as well as the precipitation of the Al6Mn phase and η′ phase, resulting in the enhancement of the properties. The material fracture at the junction of the nugget zone and the heat-affected zone occurs after repair, which is attributed to the significant difference in the texture of the nugget zone and the heat-affected zone, as well as to the stress concentration at the junction. [ABSTRACT FROM AUTHOR]

The promising structural properties of fiber-reinforced polymer composites make them widely popular in the energy, automotive, defense, and aerospace industries. One of the most challenging limitations associated with the application of composites is their maintenance and repair. In this study, a polymer cold spray approach is introduced as an efficient alternative for the structural repair of fiber-reinforced polymer composites, without the use of additional repair media. Damage in the form of circular tapered holes is created in glass fiber-reinforced polymer (GFRP) composite substrates using conventional drilling. This damage is repaired by cold spray with thermoplastic (nylon 6) and thermosetting (polyester epoxy resin) materials. The fundamental adhesion mechanisms near the repair surface are investigated through microstructural observations and highlight the role of adiabatic shear instability due to the occurrence of severe plastic deformation in the particle impact zone. Microstructural examinations also suggest that no significant fiber damage or surface degradation occurs due to the repair by cold spray. Mechanical tests performed on neat, damaged, and repaired composites reveal the partial recovery of structural performance and load-bearing capacity after cold spray repair. Additionally, the cold spray-repaired GFRP samples are compared with conventional epoxy resin repair methods. Results obtained in this work highlight cold spray as a promising and rapid technique for the on-site repair of composite structures with minimal pre-/post-processing requirements. [ABSTRACT FROM AUTHOR]

The high efficiency and low cost repair of perforation damage of aluminum honeycomb sandwich structure is of great significance to ensure the integrity of aviation equipment. A composite carbon fiber wet patch bonding repair process is proposed for metal panels with perforated damage in aluminum honeycomb sandwich structures. Combined with typical aluminum honeycomb sandwich structures in aircraft, intact and perforated damage samples are prepared, and composite bonding repair is carried out on perforated damage samples. A finite element simulation analysis model for four point bending strength analysis of aluminum honeycomb sandwich structure after patching and bonding repair is established, and the influence of perforation damage size on the four point bending strength of aluminum honeycomb sandwich structure and the strength recovery after repair are analyzed through simulation calculation. The results show that the bending strength of aluminum honeycomb sandwich structure can be effectively restored by using composite materials bonding method. The results of finite element simulation are in good agreement with the experimental results. The simulation model can accurately calculate the ultimate load and failure mode of all kinds of samples. The simulation results show that when the damage range is ≤φ30 mm (diameter to width ratio is less than 40%),the adhesive repair technology of composite materials can be applied to the damage repair of aluminum honeycomb sandwich structures of aircraft.

People's choice of cosmetics is no longer just 'Follow the trend', but pays more attention to the ingredients of cosmetics, whether the ingredients of cosmetics are beneficial to people's skin health; therefore, more and more skinhealthy ingredients have been discovered and used in cosmetics. In this work, atomic force microscope (AFM) is used to provide physical information about biomolecules and living cells; it brings us a new method of high-precision physical measurement. Centella asiatica (L.) extract has the ability to promote skin wound healing, but its healing effect on damagedHaCaT cells needs to be investigated, which plays a key role in judging the effectiveness of skincare ingredients. The objective of this study was to explore the impact of Centella asiatica (L.) extract on ethanol-damaged human immortalised epidermal HaCaT cells based on AFM. We established a model of cellular damage and evaluated cell viability using the MTT assay. The physical changes of cell height, roughness, adhesion and Young's modulus were measured by AFM. The findings indicated that the Centella asiatica (L.) extract had a good repair effect on injured HaCaT cells, and the optimal concentration was 75 µg/mL. [ABSTRACT FROM AUTHOR]

The difference in the strengthening effect of different thickness reinforcement plates on an LY12 aluminum alloy central defect plate and the load distribution between the reinforcement plate and central defect plate in the reinforcement plate structure were studied. Through a method of equivalent transverse load in a small interval [a + Δa], the equivalent cyclic load of the central defect plate in the reinforced plate structure under different crack lengths was calculated, and then the distribution of the internal load of the reinforced plate structure with a different thickness with the crack propagation was solved. The secondary development program of the finite element software Abaqus was written in Python language, so that Abaqus software can solve the problem of high cycle fatigue. The finite element simulation of the different thickness-reinforced plate structure is carried out by this program. Through the output data, the equivalent cyclic load of the central defect plate in the reinforced plate structure under different crack lengths is calculated. Through three different fitting methods, the mathematical relationship between the equivalent cyclic load Δ σ and the crack length a at both ends of the central defect plate in the reinforced plate structure is described. Based on the mathematical relationship and the finite element output data, the fatigue crack propagation life of the reinforced plate structures with different thicknesses is calculated. It is found that, under the same crack conditions, with the increase in the thickness of the reinforced plate, the bearing load of the cracked plate decreases and the life of the cracked plate increases. With the expansion of the crack, the bearing load ratio of the reinforced plate increases. The simulation method is compared with the experimental results to verify its effectiveness. [ABSTRACT FROM AUTHOR]

Spina bifida is one of the neural tube defects, with a high incidence in human birth defects, which seriously affects the health and quality of life of patients. In the treatment of bone defects, the source of autologous bone is limited and will cause secondary damage to the patient. At the same time, since the bone tissue in animals needs to play a variety of biological functions, its complex structure cannot be replaced by a single material. The combination of mechanical materials and biological materials has become a common choice. Human umbilical cord mesenchymal stem cells (hUC-MSCs) have the advantages of easy access, rapid proliferation, low immunogenicity, and no ethical issues. It is often used in the clinical research of tissue regeneration and repair. Therefore, in this study, we established a spina bifida model using Japanese white rabbits. This model was used to screen the best regenerative repair products for congenital spina bifida, and to evaluate the safety of regenerative repair products. The results showed that the combination of hUC-MSCs with collagen material had better regeneration effect than collagen material alone, and had no negative impact on the health of animals. This study provides a new idea for the clinical treatment of spina bifida, and also helps to speed up the research progress of regenerative repair products. [ABSTRACT FROM AUTHOR]

Timely repair of fused silica damage ensures the stable operation of high-power laser systems. In the traditional repair process, the material nearby the damaged area is gradually ablated with CO2 or femtosecond laser. Subsequently, homogenization and residual stress removal are required because of the microcracks and thermal accumulation generated with the ablation. As a result, the repair efficiency is greatly restricted. In this paper, a new method using in-volume, selective femtosecond laser-induced etching to repair the damage of fused silica is proposed. The region irradiated by femtosecond laser becomes more susceptible to the etching solution due to its constitutive characteristics having undergone chemical restructuring. In this way, material nearby the damaged area transparent to the laser radiation is modified locally inside the volume. A femtosecond laser is used to scan the damaged area with a 3D hollow trajectory. The applicable modification of fused silica occurs when the single pulse energy is approximately 2 μJ to 5 μJ, the repetition frequency is approximately 200 kHz to 500 kHz, and the scanning speed is approximately 10 mm/s. Then, the etching solution reacts quickly along the 3D profile of the modified path, and the damaged area is removed as a whole piece. This method can greatly reduce the workload of repair, and the etching process of fused silica is carried out synchronously. So, the etching efficiency is not affected by the number of damage points. In addition, the weak reaction between the etching solution and the substrate could homogenize the interface. It provides an efficient way to repair the surface damage of fused silica. [ABSTRACT FROM AUTHOR]

The damaged sample rapidly lost weight from the initial stage of oxidation, and after 360 min of oxidation, the weight loss reached 21.16 %. The C/C substrate was exposed to air when the coating was damaged, the C is rapidly oxidized into CO 2 gas, causing severe weight loss. After repair, the damaged area of the sample is completely covered, protecting it from oxidation. In addition, the SiOC ceramic generated by the pyrolysis of the repair agent had good thermal stability and lower oxygen diffusion rate. The weight loss after 360 min of oxidation at 1500 °C decreased greatly from 21.16 % to 2.4 % after repair. [Display omitted] • The effects of damage on the high-temperature properties of coated C/C were analyzed, and the failure behavior was studied. • Using polysiloxane and SiC-ZrB 2 powder as repair agents to recover the oxidation resistance property of the damaged coating. • The weight loss after 360 min of oxidation at 1500 °C decreased greatly from 21.16 % to 2.4 % after repair. The impacts of damage on the thermal barrier performance of SiC-ZrB 2 /SiC coating of C/C composites were investigated. The microstructure, chemical components, and thermal protection performance of the damaged coating before and after repair were analyzed, and the failure behavior of the damaged coated C/C composites was studied. After oxidation at 1500 °C for 360 min, the weight loss of the undamaged sample was −0.38 %, while that of the damaged sample reached 21.16 %. A repair method using polysiloxane and SiC-ZrB 2 powder as repair agent was employed to recover the oxidation resistance property of the damaged coating. The repair agent generated Si O C ceramics after high-temperature treatment, covering the damaged area and bonding well with the original coating. The weight loss of the repaired sample was 2.4 %, which was significantly improved compared to the damaged coating. This work offers a research foundation for the optimization of the repair of damaged silicon-based ceramic coatings. [ABSTRACT FROM AUTHOR]

• The inherent strain method significantly reduces running time. • Deposition along crack is more effective than along loading directions. • Optimal in-plane dimensions and maximum thickness of deposited WAAM were achieved. • Maximum stresses notably decrease by using a suitable deposition strategy. Wire and arc additive manufacturing (WAAM), also known as wire arc directed energy deposition (WA-DED), offers valuable capabilities not only for manufacturing but also for strengthening and repairing aging components. This paper employs the finite element (FE) method to investigate the influence of deposition parameters on the strengthening efficiency of damaged steel plates strengthened by WAAM material. The study calibrates the inherent strain method (ISM) with thermo-mechanical analysis to accurately predict residual stresses (RS) in manufactured samples, demonstrating that the ISM enhances computational efficiency while effectively predicting RS. It thoroughly examines key parameters such as the deposition direction, maximum thickness, and the geometric configuration of the WAAM material, including shapes and in-plane dimensions. The results indicate that deposition perpendicular to the loading direction provides better performance compared to deposition along the loading direction as it induces less normal and through-thickness stresses. Furthermore, this research determines the optimal maximum thickness for the WAAM material, showing that an increase in thickness can lead to higher maximum tensile stresses at the interface between the newly WAAM material and the underlying base plate. The study also establishes the optimal in-plane dimensions for the WAAM material. The results suggest placing the maximum thickness of WAAM material near the damaged area and gradually decreasing it in two directions to ensure sufficient stiffness around the cracked area, while avoiding an abrupt change in stiffness. This approach generates appropriate compressive stresses around the crack tip and decreases maximum tensile stresses in the plate. The study further illustrates that employing a proper printing strategy without a subsequent machining process can effectively reduce the maximum tensile stress in the steel plate while minimizing material usage. [ABSTRACT FROM AUTHOR]

The difference in the strengthening effect of different thickness reinforcement plates on an LY12 aluminum alloy central defect plate and the load distribution between the reinforcement plate and central defect plate in the reinforcement plate structure were studied. Through a method of equivalent transverse load in a small interval [a + Δa], the equivalent cyclic load of the central defect plate in the reinforced plate structure under different crack lengths was calculated, and then the distribution of the internal load of the reinforced plate structure with a different thickness with the crack propagation was solved. The secondary development program of the finite element software Abaqus was written in Python language, so that Abaqus software can solve the problem of high cycle fatigue. The finite element simulation of the different thickness-reinforced plate structure is carried out by this program. Through the output data, the equivalent cyclic load of the central defect plate in the reinforced plate structure under different crack lengths is calculated. Through three different fitting methods, the mathematical relationship between the equivalent cyclic load Δσ and the crack length a at both ends of the central defect plate in the reinforced plate structure is described. Based on the mathematical relationship and the finite element output data, the fatigue crack propagation life of the reinforced plate structures with different thicknesses is calculated. It is found that, under the same crack conditions, with the increase in the thickness of the reinforced plate, the bearing load of the cracked plate decreases and the life of the cracked plate increases. With the expansion of the crack, the bearing load ratio of the reinforced plate increases. The simulation method is compared with the experimental results to verify its effectiveness.

Sleep, a conservative evolutionary behavior of organisms to adapt to changes in the external environment, is divided into natural sleep, in a healthy state, and sickness sleep, which occurs in stressful environments or during illness. Sickness sleep plays an important role in maintaining energy homeostasis under an injury and promoting physical recovery. Tea, a popular phytochemical-rich beverage, has multiple health benefits, including lowering stress and regulating energy metabolism and natural sleep. However, the role of tea in regulating sickness sleep has received little attention. The mechanism underlying tea regulation of sickness sleep and its association with the maintenance of energy homeostasis in injured organisms remains to be elucidated. This review examines the current research on the effect of tea on sleep regulation, focusing on the function of tea in modulating energy homeostasis through sickness sleep, energy metabolism, and damage repair in model organisms. The potential mechanisms underlying tea in regulating sickness sleep are further suggested. Based on the biohomology of sleep regulation, this review provides novel insights into the role of tea in sleep regulation and a new perspective on the potential role of tea in restoring homeostasis from diseases. [ABSTRACT FROM AUTHOR]

Autophagy and endoplasmic reticulum (ER) stress response are among the key pathways regulating cold resistance of fish through eliminating damaged cellular components and facilitating the restoration of cell homeostasis upon exposure to acute cold stress. The transmembrane protein 39A (TMEM39A) was reported to regulate both autophagy and ER stress response, but its vertebrate-specific paralog, the transmembrane protein 39B (TMEM39B), has not been characterized. In the current study, we generate tmem39b-knockout zebrafish lines and characterize their survival ability under acute cold stress. We observed that the dysfunction of Tmem39b remarkably decreased the cold resilience of both the larval and adult zebrafish. Gene transcription in the larvae exposed to cold stress and rewarming were characterized by RNA sequencing (RNA-seq) to explore the mechanisms underlying functions of Tmem39b in regulating cold resistance. The results indicate that the deficiency of Tmem39b attenuates the up-regulation of both cold- and rewarming-induced genes. The cold-induced transcription factor genes bif1.2, fosab, and egr1, and the rewarming-activated immune genes c3a.3, il11a, and sting1 are the representatives influenced by Tmem39b dysfunction. However, the loss of tmem39b has little effect on the transcription of the ER stress response- and autophagy-related genes. The measurements of the phosphorylated H2A histone family member X (at Ser 139, abbreviated as γH2AX) demonstrate that zebrafish Tmem39b protects the cells against DNA damage caused by exposure to the cold-warming stress and facilitates tissue damage repair during the recovery phase. The gene modules underlying the functions of Tmem39b in zebrafish are highly enriched in biological processes associated with immune response. The dysfunction of Tmem39b also attenuates the up-regulation of tissue C-reactive protein (CRP) content upon rewarming. Together, our data shed new light on the function and mechanism of Tmem39b in regulating the cold resistance of fish. [ABSTRACT FROM AUTHOR]

There are strict requirements on the surface-shape accuracy, cracks, scratches, and subsurface damage of photomask glass substrates with the advancement of photo-etching technology. In this study, photomask quartz glass substrates were etched with the hydrofluoric (HF) acid etching method after chemical mechanical polishing (CMP), so that the polishing hydrolysis layer could be completely removed. In addition, the surface scratches caused by CMP were observed with a surface quality detection device and a white light interferometer. Second, the high-efficiency array-type magnetorheological polishing technology was employed to eliminate the surface-shape error on the surface of quartz photomask glass substrates. Finally, the removal function rotation angle based magnetorheological polishing technology was utilized to evenly remove the mid-frequency ripples and scratches caused in the preceding technological process. The experimental results demonstrated that these technologies can be used to realize rapid damage removal and high-quality processing of photomask glass substrates. [ABSTRACT FROM AUTHOR]

Bionic electrical stimulation (Bio-ES) aims to achieve personalized therapy and proprioceptive adaptation by mimicking natural neural signatures of the body, while current Bio-ES devices are reliant on complex sensing and computational simulation systems, thus often limited by the low-fidelity of simulated electrical signals, and failure of interface information interaction due to the mechanical mismatch between soft tissues and rigid electrodes. Here, the study presents a flexible and ultrathin self-sustainable bioelectronic patch (Bio-patch), which can self-adhere to the lesion area of organs and generate bionic electrical signals synchronized vagal nerve envelope in situ to implement Bio-ES. It allows adaptive adjustment of intensity, frequency, and waveform of the Bio-ES to fully meet personalized needs of tissue regeneration based on real-time feedback from the vagal neural controlled organs. With this foundation, the Bio-patch can effectively intervene with excessive fibrosis and microvascular stasis during the natural healing process by regulating the polarization time of macrophages, promoting the reconstruction of the tissue-engineered structure, and accelerating the repair of damaged liver and kidney. This work develops a practical approach to realize biomimetic electronic modulation of the growth and development of soft organs only using a multifunctional Bio-patch, which establishes a new paradigm for precise bioelectronic medicine., (© 2024 Wiley‐VCH GmbH.)

ABSTRACT Chroococcidiopsis spp. can withstand extremely harsh environments, including a Mars-like environment. However, studies are lacking on the molecular mechanisms of Chroococcidiopsis sp. surviving in Mars-like environments. In the HH-21-5 mission, the desert cyanobacterium Chroococcidiopsis sp. was exposed to a Mars-like environment (near space; 35 km altitude) for 4 h, and a single-factor environment of near space was simulated on the ground. We investigated the survival and endurance mechanisms of Chroococcidiopsis sp. ASB-02 after exposing it to near space by studying its physiological and transcriptional properties. After the exposure, Chroococcidiopsis sp. ASB-02 exhibited high cell viability, although photosystem II activity decreased and the levels of reactive oxygen species increased. The single-factor simulation experiments revealed that for the survival of Chroococcidiopsis sp. ASB-02 in near space, UV radiation was the most important limiting factor, and it was followed by temperature. The near space environment triggered multiple metabolic pathway responses in Chroococcidiopsis sp. ASB-02. The upregulation of extracellular polysaccharides as well as carotenoid and scytonemin biosynthesis genes in response to UV radiation attenuated the extent of radiation reaching the cells. At the same time, genes related to protein synthesis were upregulated in response to the low temperature, overcoming the decrease in metabolic activity that was caused by the low temperature. In near space and after rehydration, the genes involved in various DNA and photosystem II repair pathways were upregulated. This reflected the damage to the DNA and photosystem II protein subunits in cells during the flight and suggested that repair mechanisms play an important role in the recovery of Chroococcidiopsis sp. ASB-02. IMPORTANCE This study reported that the protective and repair mechanisms of Chroococcidiopsis sp. ASB-02 contributed to its endurance ability in a Mars-like near space environment. In Chroococcidiopsis sp. ASB-02, a Mars-like near space environment activated the expression of genes involved in extracellular polysaccharides (EPS), carotenoid, scytonemin, and protein syntheses, which provided additional protection. Additionally, the cell damage repair process enhanced the recovery rate of Chroococcidiopsis sp. ASB-02 after the flight. This study will help to enhance the understanding of the tolerance mechanism of Chroococcidiopsis sp. and to provide important guidance as to the survival requirements for microbial life in a Mars-like environment.

Repair is a critical step in restoring end-of-life components into their original shape or new functionality that contributes to sustainability for society. One of the advanced technologies to repair is the laser cladding process, which is an additive manufacturing technique for restoring metal component surfaces, e.g., a cylindrical shaft or downhole tools. Repairing surface damage has been challenging for several reasons, including the complexity of the path planning process. According to the literature, many researchers have focused on an automatic generation of the toolpath for laser cladding; however, most studies were developed for model building rather than repair. Thus, a general wear rebuild method is required for various types and shapes of damage. In addition, the development of a robust and effective method is feasible. This paper proposes a method to generate laser tool paths for surface damage based on a layer-by-layer rebuild approach. With reverse engineering techniques, acquired spatial measurements of the damaged surface, using a depth sensor, are employed to reconstruct the surface topology using the Delaunay method. Further, a surface unwrapping process is applied for the reconstructed mesh. Then, a new surface mesh slicing technique is developed to obtain rebuilding slices. This allows for independent path planning per layer. A unique feature of this method is the ability to control clad orientation per layer, which allows for a cross-hatching pattern path. In addition, processing normal vectors are computed to enable surface following cladding process with a minimal change in the tool's orientation and movement. Furthermore, the proposed method was tested with three practical case studies, which resulted in an effective toolpath. Lastly, the generated paths are verified in a simulated environment before producing the robot program. In the future, a practical repair process will be carried out to further investigate the effectiveness of this method and perform a metallurgical study of the clad. [ABSTRACT FROM AUTHOR]

Restoring damaged components is a very promising and high-value project, which enable to save a lot of production time and cost, and thus has already attracted wide attention, especially in the aviation industry. In the past few years, cold spray (CS) had been widely adopted in restoration and repair applications due to its unique advantages, such as no thermal influence, high efficiency, flexibility, etc. Nowadays, speeding up the product lifecycle as well as improving the accuracy and reliability of CS based repairing require an advance strategy with higher efficiency and more agility. To respond to this need, in this article, a concept on the development of a knowledge based intelligent CS repairing framework is presented. The framework includes a 3D scanning system for providing the information needed on the partially damaged part to repair, a dynamic defect repairing knowledge base for providing related standard defect geometry repairing strategy, including matching the standardized defect geometry, machining pre-treatment, CS toolpath, CS parameter setting, etc., and a CS additive repair system involving robotic repair trajectory programming, simulation and material deposition. Based on the proposed framework, the design of intelligent CS additive repair system and its flow are explained. The novel repair strategy and method proposed in this article can become a model for the metal repair industry in the future. [ABSTRACT FROM AUTHOR]

Cartilage injury is caused by inflammation, trauma, and tumor. Due to the anatomical factors of articular cartilage, its healing ability is poor. The preparation of tissue engineering materials to promote the repair of cartilage injury has attracted much attention. Magnesium and magnesium materials have attracted extensive attention because of their good biosafety, biocompatibility, degradability, and availability. They play an important role in the repair of cartilage injury such as osteoarthritis. This paper reviews the role and mechanism of magnesium and magnesium materials in the repair of articular cartilage injury. [ABSTRACT FROM AUTHOR]

[Display omitted] • Damaged SiC-ZrB 2 /SiC oatings of carbon/carbon composites were repaired using polysiloxane (PSO)-based repair agents. • The effects of the repair agent additives (Al 2 O 3 and IPA) on the morphology and oxidation performance of the repaired coatings were investigated. • The weight loss of the damaged coating after oxidation decreased from 21.16% to 0.48% after repair. Damaged SiC-ZrB 2 /SiC (SZS) coatings of carbon/carbon (C/C) composites were repaired using polysiloxane (PSO)-based repair agents. SiC-ZrB 2 powder was used as an inert filler, and Al 2 O 3 and isopropyl alcohol (IPA) were introduced as modified additives. The effects of each component of the repair agents on the chemical composition, microstructure, and oxidation behavior of the repaired coatings were investigated, and the repair mechanism was clarified. The repaired area was dense and smooth, showed good compatibility with the original coating, and remained intact after oxidation at 1500 ℃ for 360 min. The addition of Al 2 O 3 promoted the pyrolysis of PSO and formation of β-SiC, which was beneficial to the densification and oxidation resistance of the repaired coatings. The introduction of IPA improved the fluidity of the repair agents, and the repair agents infiltrated the coated C/C composites through the micropores on the damaged surface under capillary action, thereby enhancing the interfacial bonding strength. The weight loss of the damaged coating after oxidation decreased from 21.16 % to 0.48 % after repair. This work offers an approach for optimizing the repair of Si-based ceramic coatings. [ABSTRACT FROM AUTHOR]

• A high bonding strength CFRP surface laser texturing method for damage repair has been proposed. • The mechanism of resin removal during ultrafast laser ablation was revealed. • Removal of resin surface fibers and introduction of mechanical structure improve bonding properties. • The adhesive joint strength is 61.6% higher than that of manual repair. Carbon fiber reinforced polymer composite (CFRP) has a wide range of applications in aerospace, but it can cause varying degrees of damage in harsh service environments. Seeking a high-performance repair method is an effective way to save costs and ensure the service performance of CFRP components. In this study, a high bonding tensile strength of CFRP surface ultrafast laser texturing method for damage repair was proposed, which achieved complete removal of surface resin while retaining intact exposed fiber filaments. The difference in groove processing under unidirectional scanning and cross-scanning modes at different angles was explored. When the groove spacing was 0.2 mm and 0.4 mm, the surface resin was completely removed, the carbon fiber remained intact, and no debris was inside the groove. The groove morphology has a significant impact on the contact zone of the surface, which in turn affects the mechanical properties of the bonded joint. Cross-scanning can effectively improve surface roughness to increase the contact surface area. However, there is more fiber breakage, manifested as a groove weakening effect, which limits the improvement of bonding strength. In the 0° unidirectional scanning mode, the tensile performance of the joint is the best, improved by 61.6 % compared to manual processing. [ABSTRACT FROM AUTHOR]

Cellular checkpoints prevent damage and mutation accumulation in tissue cells. DNA repair is one mechanism that can be triggered by checkpoints and involves temporary cell cycle arrest and thus delayed reproduction. Repair-deficient cells avoid this delay, which has been argued to lead to a selective advantage in the presence of frequent damage. We investigate this hypothesis with stochastic modeling, using mathematical analysis and agent-based computations. We first model competition between two cell types: a cell population that enters temporary cell cycle arrest, corresponding to repair (referred to as arresting cells), and one that does not enter arrest (referred to as nonarresting cells). Although nonarresting cells are predicted to grow with a faster rate than arresting cells in isolation, this does not translate into a selective advantage in the model. Interestingly, the evolutionary properties of the nonarresting cells depend on the measure (or observable) of interest. When examining the average populations sizes in competition simulations, nonarresting and arresting cells display neutral dynamics. The fixation probability of nonarresting mutants, however, is lower than predicted for a neutral scenario, suggesting a selective disadvantage in this setting. For nonarresting cells to gain a selective advantage, additional mechanisms must be invoked in the model, such as small, repeated phases of tissue damage, each resulting in a brief period of regenerative growth. The same properties are observed in a more complex model where it is explicitly assumed that repair and temporary cell cycle arrest are dependent on the cell having sustained DNA damage, the rate of which can be varied. We conclude that repair-deficient cells are not automatically advantageous in the presence of frequent DNA damage and that mechanisms beyond avoidance of cell cycle delay must be invoked to explain their emergence.

Radiation therapy is crucial in combating malignant tumors, yet its damage to the microvascular system can significantly impair patient recovery and prognosis. Although current radiation protection measures mitigate free radical damage to target organs, they fall short in safeguarding the surrounding microvasculature. This study pioneers the use of the matrigel plug angiogenesis model to investigate the application of the water-soluble fullerene derivative Fullerenol in microvascular radioprotection, aiming to effectively protect and repair the microvascular system during radiation therapy, thereby reducing its adverse effects on healthy tissues. Our findings demonstrate that Fullerenol not only efficiently scavenges free radicals, reducing radiation-induced damage, but also promotes endothelial cell proliferation, facilitating the repair of damaged microvasculature and surrounding tissues. Additionally, Fullerenol was found to inhibit Caspase-3 and activate the PI3K/AKT (Phosphoinositide 3-kinase/Protein kinase B) proliferation metabolic pathway and its downstream proteins, such as eNOS and VEGF (Endothelial nitric oxide synthase/Vascular endothelial growth factor), decreasing endothelial cell apoptosis and maintaining vascular proliferation and angiogenesis potential. This research provides a new option for microvascular radioprotection and offers fresh insights into the repair of tissues damaged by radiation therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents comprehensive parametric analyses on the behavior of damage-repaired steel-concrete composite girders using CFRP sheets. Cross-sectional loss was considered on the lower steel flange at midspan to replicate corrosion damage in the girder. Damage was repaired using CFRP sheets to the underside of the lower flange. Non-linear Finite Element (FE) analyses were conducted on the repaired and intact composite girders. The FE models were validated using experimental results and a parametric study was carried out considering the variables such as number of CFRP sheets, CFRP elastic modulus, damage amount, epoxy resin elastic modulus, concrete strength, flange strength, and CFRP bonding area. The effect of parameters on failure components was studied for Limit States 1, 2, and 3 defined in the revised Design Specification for Highway Bridges in Japan (JSHB) (2017). Limit States 1 and 3 correspond to the service limit and ultimate Limit States in AASHTO, respectively. However, Limit State 2 is JSHB unique Limit State located between 1 and 3 in terms of functionality. Regression models were proposed to determine the load-carrying capacity of the repaired composite girder for 3 Limit States. Comparison between the proposed equation and FE-predicted values showed good agreement with prediction errors of ±10% to ±19%. The study showed that to restore the stiffness and load capacities for Limit State 1 high-modulus CFRP sheets and resins are more suitable options than the low-modulus sheets and resins. Finally, the study proposes the optimal repair method for damaged composite girder considering the Limit States. • Parametric analyses of damage repaired steel-concrete composite girder were conducted using CFRP sheets. • Effect of various parameters has been investigated. • Equations for loadcapacities of repaired composite girders for Limit States 1, 2 and 3 have been proposed. [ABSTRACT FROM AUTHOR]

Objective: The present study is intended to characterize the surfactant damage suffered by the hair cortex in routine washing and the mechanistic effect of Coconut Based Hair Oils (CBHO) to mitigate the damage. Methods: Surfactants which diffuse into the hair structure solubilize protein moieties, leading to an increase in porosity and internal surface area as well as the pore volume. The changes in hair pores occurring in the hair cortex are measured by nitrogen sorption method in line with the Brunauer‐Emmett‐Teller (BET) theory. Single fiber tensile parameters were measured using Diastron MTT 175. Color protection was measured quantitatively using spectrophotometer as well as visual rating by trained panelists. Results: The pore surface area data clearly show the benefit of introducing coconut‐based hair oils (CBHO) into the hair by preventing increase in hair porosity. A statistically significant decrease in break stress and toughness were observed and the same were reversed by the application of CBHO. A pronounced color protection effect was also recorded with the application of CBHO. Conclusion: The porosity reduction effect seen with the use of CBHO is attributed to the CBHO molecules blocking the diffusion pathways in the endocuticle and the matrix part of the cortical cells, limiting protein surfactant interaction resulting in reduced solubilization and loss. Since, the color molecules are likely to be much smaller than the protein moieties, a pronounced color protection effect suggests that the penetrated CBHO molecules form a dense diffusion barrier in the matrix, cell membrane complex (CMC) and the endocuticle regions of hair – which are the main diffusion pathways out of hair. The study confirms the damage repair potential of CBHO and that it works by increasing the hydrophobicity of hair – both on the hair surface and in the cortex. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nickel-based cast superalloy is one of the main materials applied in the manufacture of aeroengine and gas turbine,and it is widely applied in aerospace,energy industry and shipbuilding industries etc.The rapid development of modern aviation industry is inseparable from the rapid improvement of the comprehensive performance of superalloys, and the application of hot isostatic pressing technology in the field of nickel-based casting superalloys plays a pivotal role in improving the comprehensive performance of nickel-based casting superalloys. In this paper, the working principle and application history of hot isostatic pressing technology were introduced. The research and application status of hot isostatic pressing technology in the field of nickel-based casting superalloys was summarized. The research on the effect of hot isostatic pressing on the densification mechanism and microstructure properties of cast superalloys, research on hot isostatic pressing on the microstructure repair of nickel-based cast superalloys in long-term service, and research on the realization of the diffusion bonding of two nickel-based superalloys progress are highlighted and elaborated. At the same time, some problems in the research of hot isostatic pressing technology and the development trend of domestic hot isostatic pressing technology in the field of nickel-based cast superalloys were pointed out.

Timely repair of fused silica damage ensures the stable operation of high-power laser systems. In the traditional repair process, the material nearby the damaged area is gradually ablated with CO2 or femtosecond laser. Subsequently, homogenization and residual stress removal are required because of the microcracks and thermal accumulation generated with the ablation. As a result, the repair efficiency is greatly restricted. In this paper, a new method using in-volume, selective femtosecond laser-induced etching to repair the damage of fused silica is proposed. The region irradiated by femtosecond laser becomes more susceptible to the etching solution due to its constitutive characteristics having undergone chemical restructuring. In this way, material nearby the damaged area transparent to the laser radiation is modified locally inside the volume. A femtosecond laser is used to scan the damaged area with a 3D hollow trajectory. The applicable modification of fused silica occurs when the single pulse energy is approximately 2 μJ to 5 μJ, the repetition frequency is approximately 200 kHz to 500 kHz, and the scanning speed is approximately 10 mm/s. Then, the etching solution reacts quickly along the 3D profile of the modified path, and the damaged area is removed as a whole piece. This method can greatly reduce the workload of repair, and the etching process of fused silica is carried out synchronously. So, the etching efficiency is not affected by the number of damage points. In addition, the weak reaction between the etching solution and the substrate could homogenize the interface. It provides an efficient way to repair the surface damage of fused silica.

Sleep, a conservative evolutionary behavior of organisms to adapt to changes in the external environment, is divided into natural sleep, in a healthy state, and sickness sleep, which occurs in stressful environments or during illness. Sickness sleep plays an important role in maintaining energy homeostasis under an injury and promoting physical recovery. Tea, a popular phytochemical-rich beverage, has multiple health benefits, including lowering stress and regulating energy metabolism and natural sleep. However, the role of tea in regulating sickness sleep has received little attention. The mechanism underlying tea regulation of sickness sleep and its association with the maintenance of energy homeostasis in injured organisms remains to be elucidated. This review examines the current research on the effect of tea on sleep regulation, focusing on the function of tea in modulating energy homeostasis through sickness sleep, energy metabolism, and damage repair in model organisms. The potential mechanisms underlying tea in regulating sickness sleep are further suggested. Based on the biohomology of sleep regulation, this review provides novel insights into the role of tea in sleep regulation and a new perspective on the potential role of tea in restoring homeostasis from diseases.

There are strict requirements on the surface-shape accuracy, cracks, scratches, and subsurface damage of photomask glass substrates with the advancement of photo-etching technology. In this study, photomask quartz glass substrates were etched with the hydrofluoric (HF) acid etching method after chemical mechanical polishing (CMP), so that the polishing hydrolysis layer could be completely removed. In addition, the surface scratches caused by CMP were observed with a surface quality detection device and a white light interferometer. Second, the high-efficiency array-type magnetorheological polishing technology was employed to eliminate the surface-shape error on the surface of quartz photomask glass substrates. Finally, the removal function rotation angle based magnetorheological polishing technology was utilized to evenly remove the mid-frequency ripples and scratches caused in the preceding technological process. The experimental results demonstrated that these technologies can be used to realize rapid damage removal and high-quality processing of photomask glass substrates.

Long-term exposure of human skin to ultraviolet light can cause cell damage, and UVA mainly causes skin photoaging. The purpose of this study is to prove that the extracellular polysaccharide (LPL-EPS-02) isolated from a kind of Lactobacillus plantarum isolated from kimchi can protect and repair human fibroblasts after UVA irradiation. In this experiment, real-time reverse transcription-polymerase chain reaction (qRT-PCR) and ELISA methods were used to establish a UVA-irradiated human dermal fibroblast (HDF) model to explore the damage caused by UVA and LPL-EPS-02 protection and repair of the HDF from the cellular and molecular levels. LPL-EPS-02 can alleviate the oxidative stress caused by UVA irradiation, promote the production of antioxidant enzymes, and remove excessive free radicals. In addition, LPL-EPS-02 can also slow down the degree of collagen cross-linking caused by UVA and improve skin photoaging caused by sunlight. LPL-EPS-02 can also effectively prevent and repair skin photoaging caused by ultraviolet radiation by affecting the expression levels of TGF-β related transcription factors in HDF.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: The aim of this study was to investigate the molecular mechanism underlying odontoblast damage repair in dentin hypersensitivity (DH) and the role of Yes-associated protein (YAP) in this process., Methods: The DH model was constructed in Sprague-Dawley (SD) rats, and the in vivo expression of Piezo1, Integrin αvβ3, YAP, and dentin sialophosphoprotein (DSPP) was detected by immunohistochemistry. COMSOL Multiphysics software was used to simulate the dentinal tubule fluid flow velocity and corresponding fluid shear stress (FSS) on the odontoblast processes. MDPC-23 cells were cultured in vitro and loaded with a peristaltic pump for 1 hour at FSS values of 0.1, 0.3, 0.5, and 0.7 dyne/cm 2 . The expression of Piezo1, Integrin αvβ3, and YAP was detected by immunofluorescence. Verteporfin (a YAP-specific inhibitor) was utilised to confirm the effect of YAP on the expression of dentineogenesis-related protein under FSS., Results: The level and duration of external mechanical stimuli have an effect on the functional expression of odontoblasts. In DH, the harder the food that is chewed, the faster the flow of the dentinal tubule fluid and the greater the FSS on the odontoblast processes. The expression of Piezo1, Integrin αvβ3, and YAP can be promoted when the FSS is less than 0.3 dyne/cm 2 . After YAP inhibition, the DSPP protein expression level was reduced at 0.3 dyne/cm 2 FSS., Conclusions: These results suggest that appropriate FSS can enhance the expression of odontoblast-related factors in odontoblasts via the Piezo1-Integrin αvβ3-YAP mechanotransduction pathway and the YAP appears to play an essential role in the response of odontoblasts to external mechanical stimuli., Competing Interests: Conflict of interest None disclosed., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

In the article is presented an analysis of the life cycle costs calculation for selected roof coverings. The scope of research includes costs of construction, maintenance and demolition of the roof covering structure for two alternative technologies – the traditional and new generation. On the presented example of an industrial building with a roof area of 1000 m2, the above costs are taken to consideration for the roof covering made of two thermoplastic asphalt torching polymer membrane layers and a new generation PVC thermoplastic film with a reinforcing layer. The input data presented in the article comes from the investor (the owner of the future facility) and from property managers responsible for the maintenance of facilities in regard to the purpose, volume and applied method.

Objective To investigate the repair effect of bone marrow mesenchymal stem cells (BMSCs) on pulmonary vascular endothelial injury in rats with chronic obstructive pulmonary disease (COPD) -obstructive sleep apnea (OSA) overlap syndrome and to explore its possible mechanism. Methods BMSCs were isolated from femur and tibial bone marrow of SPF-grade female SD rats, and then were cultured and identified. Sixteen female SD rats with SPF grade were selected to prepare the RAT models of COPD-OSA overlap syndrome by smoking combined with intermittent hypoxia. The rats were randomly divided into the observation group and control group, with 8 rats in each group. The rats in the observation group were injected with 2 × 106 BMSCs per time, once a week, for 4 times in total, and the rats in the control group were injected with normal saline of the same volume. One week after treatment, the rats in the two groups were sacrificed, the lung tissues were taken for paraffin section for HE staining and MASSON staining to observe the pathological changes of the lung tissues and pulmonary arteriole, and the apoptosis of vascular endothelial cells in the lung tissues was observed by the triple qualitative method of DAPI-CD34-TUNEL,the expression levels of endothelin 1 (ET-1), endothelial nitric oxide synthase (e NOS), vascular endothelial growth factor (VEGF) and stromal cell derived factor 1 (SDF-1) were detected by ELISA. Results Compared with the control group, the pathological changes of the lung tissues in the observation group were milder, such as emphysema, interstitial lymphocyte infiltration, neutrophil infiltration, bronchial wall lymphocyte hyperplasia, bronchiolar wall smooth muscle hyperplasia and goblet cell hyperplasia; the changes of pulmonary arterioles myosization, outer membrane collagen fiber deposition, abnormal vascular wall structure, perivascular inflammation, and pulmonary interstitial thickening were relatively mild. The apoptosis rates of pulmonary vascular endothelial cells in the observation group and the control group were 2. 3552% ± 0. 3923% and 1. 3339% ± 0. 1553%,respectively,with statistically significant difference (both P ＜ 0. 01). The content of ET-1 and VEGF in lung tissue homogenization of the observation group was lower than that of the control group, and the content of e NOS was higher than that of the control group, with statistically significant difference (all P ＜ 0. 05); the SDF-1α content in lung tissue homogenization in the observation group was lower than that in the control group, but no statistically significant difference was found between these two groups (P ＞ 0. 05). Conclusions BMSCs can improve the vascular endothelial injury and dysfunction in pulmonary tissues of rats with COPD-OSA overlap syndrome, reduce the apoptosis of pulmonary vascular endothelial cells, and improve the remodeling of pulmonary tissues and small pulmonary vessels to some extent. [ABSTRACT FROM AUTHOR]

Copyright of A&C - Administrative & Constitutional Law Review - Revista de Direito Administrativo e Constitucional is the property of A&C - Revista de Direito Administrativo & Constitucional (Instituto Bacellar) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Temperature is a critical factor affecting the growth, development and reproduction of aquatic organisms. The interspecific F 1 hybrids between hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) exhibited significant heterosis in yield, but sterility in most hybrids hindered large scale interspecific hybridization and speciation. We first explored the physiological effect of temperature on the fertility of hybrid hermaphroditic Argopecten scallops with F 1 hybrids treated at 6 different temperatures (18 °C, 20 °C, 22 °C, 24 °C, 26 °C, and 28 °C). The results showed that the final mortality rates from 18 °C to 22 °C were significantly lower than those from 24 °C to 28 °C. With the decrease of the temperature, the size, gonadal index, ATP content, and expression of most genes related to fertility regulation gradually decreased in F 1 hybrids treated at 22 °C, 20 °C and 18 °C, and the apoptosis rate of oocytes gradually increased, but the activity of SOD (superoxide dismutase) and CAT (catalase) first increased and then decreased. The fertility of hybrids treated at 22 °C, 20 °C and 18 °C gradually decreased with the decrease of the temperature. According to gene expression, temperature may regulate the fertility of Argopecten F 1 hybrids by affecting apoptosis, meiosis, ATP production and damage repair to inhibit the genesis and maturation of germ cells. Our findings suggest that temperature can affect the hybrid fertility of hermaphroditic Argopecten scallops and provide the basis for further research on the mechanism of temperature on sterility. • Effect of temperature on fertility of hybrid hermaphroditic Argopecten scallops was first explored. • 22 °C may be a better cultivation temperature to obtain higher fertility. • Temperature affects the level of apoptosis and growth of hybrid scallops. • Temperature affects gonadal development and fertility of hybrid scallops. [ABSTRACT FROM AUTHOR]

This study investigated the behavior of corrosion damage-repaired steel–concrete composite girders with CFRP sheets using finite element (FE) analysis. The corrosion-induced damage in the girder was simulated by removing a cross-sectional area of 1480 mm × 4.5 mm from the top surface of the bottom steel flange at the midspan. Afterward, six-layer CFRP sheets were bonded to the underside of the lower flange with epoxy resin as a repair method. A reference model without damage was also considered. FE models of these specimens were established, and a nonlinear FE analysis was conducted. The FE models were validated using experimental results and then used to perform a parametric study considering the limited number of parameters: number of layers and elastic modulus of CFRP sheets. Comparison between experimental and numerical results revealed that the FE simulation could accurately capture the failure orders and predict the comprehensive behavior of CFRP-repaired steel concrete composite girders. Furthermore, an equation was proposed to predict the carrying load-carrying capacity of the CFRP-repaired steel-concrete composite girder. The proposed equation was used to calculate the targeted load-carrying capacity and showed closer values to the numerical results. However, more parameters are required to include in the equation for the rational design method. • A comprehensive numerical analysis on the repair of a damaged composite girder using CFRP sheets was conducted. • The effect of number of layers and the elastic modulus of CFRP sheet were investigated. • An equation to determine the load carrying capacity of repaired steel-concrete composite girder was proposed. [ABSTRACT FROM AUTHOR]

It has been demonstrated that the sekelsky mothers against decapentaplegic homolog 3 (Smad3) plays an important role in the growth and development of vertebrates. However, little is known about the association between the Smad3 gene and the growth traits of mollusks. In this study, Smad3 from the hard clam Meretrix meretrix (Mm-Smad3) was cloned, characterized, and screened for growth-related single nucleotide polymorphisms (SNPs) in its exons. The full-length cDNA of Mm-Smad3 was 1938 bp, encoding a protein with 428 amino acid residues. The protein sequence included an MH1 (27–135 aa) and MH2 domain (233–404 aa). Promoter analysis showed that the promoter sequence of Mm-Smad3 was 2548 bp, and the binding sites of Pit-1a, Antp, Hb, and other transcription factors are related to the growth and development of hard clams. The phylogenetic tree was divided into two major clusters, including mollusks and vertebrate. The expression level of Mm-Smad3 was predominantly detected in the mantle and foot, while extremely less expression was observed in the digestive gland. The low expression level of Mm-Smad3 was detected at the stages of unfertilized mature eggs, fertilized eggs, four-cell embryos, blastula, gastrulae, trochophore, and D-shaped larvae, whereas an opposite trend was observed regarding the highest expression at the umbo larvae stage (p < 0.05). In the mantle repair experiment, the time-course expression profiles showed that compared to the expression level at 0 h, Mm-Smad3 significantly decreased at 6 h (p < 0.05) but increased at 12 and 48 h. Further, the association analysis identified 11 SNPs in the exons of Mm-Smad3, of which three loci (c.597 C > T, c.660 C > T, c.792 A > T) were significantly related to the growth traits of clam (p < 0.05). Overall, our findings indicated that Mm-Smad3 is a growth-related gene and the detected SNP sites provide growth-related markers for molecular marker-assisted breeding of this species.

The hydrogen peroxide-induced small RNA OxyS has been proposed to originate from the 3' UTR of a peroxide mRNA. Unexpectedly, phylogenetic OxyS targetome predictions indicate that most OxyS targets belong to the category of "cell cycle," including cell division and cell elongation. Previously, we reported that Escherichia coli OxyS inhibits cell division by repressing expression of the essential transcription termination factor nusG , thereby leading to the expression of the KilR protein, which interferes with the function of the major cell division protein, FtsZ. By interfering with cell division, OxyS brings about cell-cycle arrest, thus allowing DNA damage repair. Cell division and cell elongation are opposing functions to the extent that inhibition of cell division requires a parallel inhibition of cell elongation for the cells to survive. In this study, we report that in addition to cell division, OxyS inhibits mepS , which encodes an essential peptidoglycan endopeptidase that is responsible for cell elongation. Our study indicates that cell-cycle arrest and balancing between cell division and cell elongation are important and conserved functions of the oxidative stress-induced sRNA OxyS., (© 2024 Elgrably-Weiss et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.)

The traditional geotechnical engineering deformation repair method takes a long time, has low precision and poor effect. In order to solve this problem, a method of geotechnical engineering deformation damage repair based on elastic–plastic mechanics is proposed. Firstly, the balance equation, constitutive equation and evolution equation of deformation and damage in geotechnical engineering are established; then the deformation and failure process of geotechnical engineering is deduced, and the failure value of rock mass is calculated; finally, the deformation and damage repair in geotechnical engineering is completed by using elastic–plastic mechanics method. The experimental results show that, compared with other methods, the damage value of this method is consistent with the actual damage value, and the repair accuracy is high. The calculation time is in the range of 2–4 s, and the repair efficiency is high. Moreover, this method can achieve the ideal effect of geotechnical engineering deformation repair. [ABSTRACT FROM AUTHOR]

It has recently been found that derivatives of nucleotides containing а 3-hydroxychromone fluorescent dye can be used as sensitive markers of conformational changes of DNA. In this work, a comparative analysis of two fluorescent nucleotide derivatives—3-hydroxychromone a (3HC) and 3HC-modified uridine (FCU)—was performed during the study of protein–nucleic acid interactions for several human DNA repair enzymes, removing damaged nucleotides: DNA glycosylases AAG, OGG1, UNG2, and MBD4 and AP endonuclease APE1. The changes of fluorescence intensity significantly depended on the nature of neighbor nucleotides and may be opposite in direction for different cases. The FCU residue located in the complementary strand opposite to damaged nucleotide or in the same strand moved by few nucleotides, is very sensitive to processes induced by DNA glycosylases in the course of formation of enzyme–substrate complexes, which include local melting and bending of the DNA chain, as well as eversion of the damaged nucleotide from DNA double helix and insertion of amino acids of the active site into the void. [ABSTRACT FROM AUTHOR]

Over the last decade, several theoretical models have been put forth to describe how animals respond to adverse environments and how this response changes under different physiological demands across life history stages. These models capture the context- and condition-dependent nature of stress responses. Yet, application of the models has been limited thus far in part because each model addresses different aspects of the problems facing the field of stress biology. Thus, there is a need for a unifying theoretical model that incorporates changes in physiological demand with life history stages and age, intricate relationships among physiological systems, and biphasic nature of stress responses. Here, I propose a new integrative framework, the Damage-Fitness Model. In this model, regulators, such as DNA repair mechanisms and glucocorticoids, work together as anti-damage mechanisms to minimize damage at both the cellular and organismal level. When the anti-damage regulators are insufficient or inappropriate, persistent damage accumulates. Previous studies indicate that these damage directly impact reproductive performance, disease risk, and survival. The types of regulators, the threshold at which they are initiated, and the magnitude of the responses are shaped by developmental and current environments. This model unites existing theoretical models by shifting our focus from physiological responses to downstream consequences of the stress responses, circumventing context specificity. Discussions include (1) how the proposed model relates to existing models, (2) steps to test the new model, and (3) how this model can be used to better assess the health of individuals and a population. Lay summary The field of stress physiology faces a challenge of characterizing dynamic cellular, physiological, and behavioral responses when animals encounter a stressor. This paper proposes a new theoretical model which links stress avoidance, damage repair and accumulation, and fitness components. [ABSTRACT FROM AUTHOR]

Antimicrobial efficacy, which is central to many aspects of medicine, is being rapidly eroded by bacterial resistance. Since new resistance can be induced by antimicrobial action, highly lethal agents that rapidly reduce bacterial burden during infection should help restrict the emergence of resistance. To improve lethal activity, recent work has focused on toxic reactive oxygen species (ROS) as part of the bactericidal activity of diverse antimicrobials. We report that when Escherichia coli was subjected to antimicrobial stress and the stressor was subsequently removed, both ROS accumulation and cell death continued to occur. Blocking ROS accumulation by exogenous mitigating agents slowed or inhibited poststressor death. Similar results were obtained with a temperature-sensitive mutational inhibition of DNA replication. Thus, bacteria exposed to lethal stressors may not die during treatment, as has long been thought; instead, death can occur after plating on drug-free agar due to poststress ROS-mediated toxicity. Examples are described in which (i) primary stress-mediated damage was insufficient to kill bacteria due to repair; (ii) ROS overcame repair (i.e., protection from anti-ROS agents was reduced by repair deficiencies); and (iii) killing was reduced by anti-oxidative stress genes acting before stress exposure. Enzymatic suppression of poststress ROS-mediated lethality by exogenous catalase supports a causal rather than a coincidental role for ROS in stress-mediated lethality, thereby countering challenges to ROS involvement in antimicrobial killing. We conclude that for a variety of stressors, lethal action derives, at least in part, from stimulation of a self-amplifying accumulation of ROS that overwhelms the repair of primary damage. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract This paper presents experimental and numerical results on a repaired mortar beam under bending with thin bonded carbon-epoxy patches. The influence of the patch length on the stiffness and ultimate load was analysed, comparatively to undamaged and damaged beam configurations. Numerical analyses were executed employing a developed mixed-mode I + II cohesive damage model with realistic parameters obtained experimentally in previous studies. Accurate predictions of damage propagation in bulk mortar and within adhesive were accomplished for homothetic structures with different sizes. Stress profiles were obtained along both adhesive interface and in mortar to assess the failure modes observed experimentally. Important conclusions have been drawn about appropriate strategies to be followed in order to guarantee remarkable recover of initial stiffness and strength on damaged mortar beams submitted to bending. [ABSTRACT FROM AUTHOR]

The increasing use of composite structures in aircraft constructions has made it necessary to develop repair methods that will restore the component’s original design strength without compromising its structural integrity. In this paper, the complex repair technology of the composite wing of a light plane, which was damaged during an aircraft crash, is described. The applied repair scheme should meet all the original design requirements for the plane structure.