Damaged Region Research Articles

Investigation of the hygrothermal effects on in-plane failure mechanisms of fine Z-pinned laminates

Hygrothermal effect on the in-plane behavior of fine Z-pinned laminates were studied and the failure mechanisms were explained. Artificial seawater aging experiments were carried out on Z-pinned laminates prepared by ultrasonic vibration equipment. A compression progressive damage numerical model of fine Z-pinned laminates based on moisture-induced interface degradation was proposed to analyze the damage initialization and development of composites. The mechanical results show that the unpinned and Φ0.11 mm Z-pinned laminates have similar in-plane strength retention after 6 months of aging, and the tensile and compressive strengths decrease by 20% and 29%, respectively. EDS analysis confirms that Z-pin provides an additional moisture channel, leading to more elements with high relative atomic mass inside the laminates. It is found through the simulation studies that moisture leads to matrix compression and interlaminar interfacial damage regions to localized areas, weakening the interlayer effect of Z-pins and leading to the decrease of the ultimate bearing capacity of laminates. It denotes that Φ0.11 mm fine Z-pin has the potential to be used in composite marine structures.

Thermal model to investigate temperature distribution with a hollow notched K-wire for bone drilling

K-wire drilling is commonly used in orthopedic surgeries, generating significant heat that can lead to bone thermal osteonecrosis. To understand the heat propagation and thermal damage region, a mathematical model of the negative rake angle on the hollow notched K-wire was established. Subsequently, a theoretical model of the shear angle for this negative rake angle was proposed. Based on these models, a comprehensive theoretical model of the heat flux was derived. The accurate heat flux was determined using the theoretical values, and experimental temperature data through inverse heat transfer method (IHTM). This heat flux was then applied in a finite element analysis to simulate the heat transfer process and identify thermal damage regions under different drilling conditions. Results showed that the thermal damage region of bone with a solid K-wire, hollow notched K-wire without cooling, with air cooling, and with water cooling were approximately 6.4 mm, 3.2 mm, 2.6 mm, and 4.8 mm in width, respectively, and 6.79 mm, 6.45 mm, 6.39 mm, and 6.58 mm in depth, respectively. This study demonstrates that the hollow notched K-wire with air cooling is a potential solution to reduce the thermal damage region, thereby accelerating patient recovery.

Chondrocyte autophagy mechanism and therapeutic prospects in osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis characterized by progressive cartilage degradation, with its pathogenesis closely related to chondrocyte autophagy. Chondrocytes are the only cells in articular cartilage, and the function of chondrocytes plays a vital role in maintaining articular cartilage homeostasis. Autophagy, an intracellular degradation system that regulates energy metabolism in cells, plays an incredibly important role in OA. During the early stages of OA, autophagy is enhanced in chondrocytes, acting as an adaptive mechanism to protect them from various environmental changes. However, with the progress of OA, chondrocyte autophagy gradually decreases, leading to the accumulation of damaged organelles and macromolecules within the cell, prompting chondrocyte apoptosis. Numerous studies have shown that cartilage degradation is influenced by the senescence and apoptosis of chondrocytes, which are associated with reduced autophagy. The relationship between autophagy, senescence, and apoptosis is complex. While autophagy is generally believed to inhibit cellular senescence and apoptosis to promote cell survival, recent studies have shown that some proteins are degraded by selective autophagy, leading to the secretion of the senescence-associated secretory phenotype (SASP) or increased SA-β-Gal activity in senescent cells within the damaged region of human OA cartilage. Autophagy activation may lead to different outcomes depending on the timing, duration, or type of its activation. Thus, our study explored the complex relationship between chondrocyte autophagy and OA, as well as the related regulatory molecules and signaling pathways, providing new insights for the future development of safe and effective drugs targeting chondrocyte autophagy to improve OA.

Green Solutions: The Impact of Agroforestry on Climate Change Resilience- A Review

The effect of agroforestry systems on resilience to climate change, highlighting their function in improving biodiversity and reducing environmental degradation. Agroforestry offers creative ways to enhance soil health, trap carbon, and boost agricultural output while benefiting communities socioeconomically by incorporating trees into agricultural settings. Stakeholders may improve food security, rebuild ecosystems, and support the livelihoods of marginalized communities by supporting agroforestry techniques. This assessment promotes greater funding for agroforestry implementation and research, which may encourage international cooperation. Adopting eco-friendly solutions, such as agroforestry, will be essential to accomplishing sustainable development objectives and building a resilient future for the world community as climate threats worsen. Additionally, by maximising the use of natural resources, agroforestry practices lessen the burden on forests and aid in the restoration of damaged regions. Climate change poses tremendous difficulties to global agriculture, affecting livelihoods, food security, and ecosystem stability. Agroforestry is a promising integrated land management technique that combines agricultural and forestry practices to lessen the effects of climate change. This summary provides an overview of the vital roles that agroforestry plays in mitigating and adapting to climate change. In order to adapt to climate change, agroforestry offers several benefits, including increased agricultural productivity, improved soil fertility, and improved water retention

Targeting the 3D genome by anthracyclines for chemotherapeutic effects.

The chromatins are folded into three-dimensional (3D) structures inside cells, which coordinates the regulation of gene transcription by the non-coding regulatory elements. Aberrant chromatin 3D folding has been shown in many diseases, such as acute myeloid leukemia (AML), and may contribute to tumorigenesis. The anthracycline topoisomerase II inhibitors can induce histone eviction and DNA damage. We performed genome-wide high-resolution mapping of the chemotherapeutic effects of various clinically used anthracycline drugs. ATAC-seq was used to profile the histone eviction effects of different anthracyclines. TOP2A ChIP-seq was used to profile the potential DNA damage regions. Integrated analyses show that different anthracyclines have distinct target selectivity on epigenomic regions, based on their respective ATAC-seq and ChIP-seq profiles. We identified the underlying molecular mechanism that unique anthracycline variants selectively target chromatin looping anchors via disrupting CTCF binding, suggesting an additional potential therapeutic effect on the 3D genome. We further performed Hi-C experiments, and data from K562 cells treated with the selective anthracycline drugs indicate that the 3D chromatin organization is disrupted. Furthermore, AML patients receiving anthracycline drugs showed altered chromatin structures around potential looping anchors, which linked to distinct clinical outcomes. Our data indicate that anthracyclines are potent and selective epigenomic targeting drugs and can target the 3D genome for anticancer therapy, which could be used for personalized medicine to treat tumors with aberrant 3D chromatin structures.

Pharmaceutical Agents for Targeting Autophagy and Their Applications in Clinics

Autophagy is the process by which damaged regions of the cytoplasm and intracellular pathogens are degraded. This mechanism often serves an adaptive role in cells, enhancing their survival. It plays a direct or indirect role in the development of various pathological conditions within the body. This phenomenon is common in various malignant diseases, where autophagy is associated with the resistance of transformed cells to chemotherapy. Conversely, abnormal activation of autophagy can trigger cell death, a process often seen in neurodegenerative conditions. Given that dysregulation of autophagy is associated with the progression of numerous pathological conditions, this is of significant interest to the developers of drugs that can effectively modulate autophagy for both basic research and clinical applications. Here, we provide a brief description of the mechanism of macroautophagy, the most prevalent form of autophagy identified in humans. We also discuss the clinical potential of drugs that can modulate autophagy, highlighting their use in combating diseases associated with direct or indirect dysregulation of this essential process.

A microstructural defect-orientation informed phase field model

Micro-cracks, micro-voids and other such defects, which typically coalesce to form macroscopic cracks, could be represented through incompatible, local rotations of material points, i.e. micro-regions. Specifically, based on a micropolar or Cosserat continuum-like hypothesis that requires attaching directors to material points, we track the evolving frame rotation and hence the microstructural orientation during quasi-brittle damage. We introduce a critical energy release rate incorporating the wryness tensor, which in turn is a function of the micro-rotation field and its gradient within the damaged region. The (pseudo) rotation field appears as additional degrees of freedom to describe a frame field, whose evolution is particularly significant within a diffused region of evolving damage as obtained through a phase-field formulation of brittle fracture. We emphasize that, unlike micropolar continua where it contributes to elastic energy, the wryness tensor appears only in the fracture energy in our approach. Thus, without damage, the solid conforms to the classical continuum. By making suitable modifications to the terms within the elastic energy and applying the principle of virtual work, we arrive at the governing partial differential equations (PDEs). For assessing the proposed framework, we choose a specific form of energy density and demonstrate, through numerical examples, the effect of the newly introduced parameters. The classical phase-field model is readily recovered by switching off the micro-rotation. Additionally, we explore a potential application of this model in representing and propagating initial defects.

Effects of magnetic nanoparticle distribution in cancer therapy through hyperthermia

Magnetic hyperthermia (MHT) is a promising cancer treatment that exploits the heating capabilities of magnetic nanoparticles (MNPs) when exposed to alternating magnetic fields. The primary challenge in optimizing MHT lies in understanding the influence of MNP distribution within the tumor microenvironment. This study presents realistic simulations of MNP distribution within a tumor, accounting for diffusion, convection, and internalization dynamics, alongside the presence of a necrotic core. Additionally, a vascular network was modeled based on diagnostic images to assess its impact on nanoparticle behavior and heat generation within the tumor. Our results show that uneven MNP distribution, particularly in areas influenced by the tumor's vasculature and necrotic regions, results in highly variable temperature profiles and irregular thermal damage. By contrast, a more uniform distribution of MNPs leads to a consistent rise in temperature and a broader region of thermal damage, with maximum temperatures reaching 47 °C and 99 % tumor cell death after 60 min of treatment. Key quantitative findings indicate that the tumor's vascular architecture plays a crucial role in determining the heat distribution and treatment efficacy. This study highlights the importance of fine-tuning MNP delivery and distribution to maximize therapeutic outcomes in MHT. The approach offers significant potential for applications in treating deep-seated or inoperable tumors, where precise and localized therapy is critical.

Growth of broken crystals tracked in 4D using X-ray computed tomography and its influence on impurity incorporation

Crystallization is a commonly used unit operation for separation and purification. During processing, crystals may break due to mechanical stress, e.g., intentionally by milling or unintentionally through collision with stirrers. This study investigates the growth of broken crystals in three dimensions using X-ray micro-computed tomography. The results show that damaged regions of crystals grow faster than faceted regions, and crystals become faceted through growth. Initially, this happens on a microscale, producing faceted but concave regions on the crystal surface. Eventually, crystals become convex. Shape-healing through growth incorporates inclusions in the crystals. These findings have important implications for designing and optimizing crystallization processes in the pharmaceutical, food, and chemical industries, as purity is often a critical quality criterion adversely affected by inclusions. In addition, the kinetics in crystallization processes are likely to be strongly affected by the growth of non-faceted and concave crystals.

Diagnostic performance of pupil perimetry in detecting hemianopia under standard and virtual reality viewing conditions.

To determine the diagnostic performance and reliability of two pupil perimetry (PP) methods in homonymous hemianopia. This cross-sectional monocenter cohort study performed gaze-contingent flicker PP (gcFPP) and a virtual reality version of gcFPP (VRgcFPP) twice on separate occasions in all patients suffering from homonymous hemianopia due to neurological impairment. The main outcomes were (1) test accuracy and (2) test-retest reliability: (1) was measured through area under the receiver operating characteristics curve (AUC) calculation of (VR)gcFPP results with comparators being SAP and healthy controls, respectively; (2) was evaluated by comparing tests 1 and 2 of both methods within patients. Both gcFPP and VRgcFPP were performed in 15 patients (12 males, MAge = 57, SDAge = 15) and 17 controls (6 males, MAge = 53, SDAge = 12). Mean test accuracy was good in separating damaged from intact visual field regions (gcFPP: Mauc = 0.83, SDauc = 0.09; VRgcFPP: Mauc = 0.69,SDauc = 0.13) and in separating patients from controls (gcFPP: Mauc = 0.92,SDauc = 0.13; VRgcFPP: Mauc = 0.96,SDauc = 0.15). A high test-retest reliability was found for the proportion intact versus damaged visual field (gcFPP: r = 0.95, P < .001, VRgcFPP: r = 1.00, P < .001). Overall, these results can be summarized as follows: (1) the comparison of pupil response amplitudes between intact versus damaged regions per patient indicate that gcFPP allows for cleaner imaging of intact versus damaged visual field regions than VRgcFPP, (2) the comparisons of average differences in intact versus damaged amplitudes between patients and controls demonstrate high diagnostic performance of both gcFPP and VRgcFPP, and (3) the test-retest reliabilities confirm that both gcFPP and VRgcFPP reliably and consistently measure defects in homonymous hemianopia. KEY MESSAGES: What is known Standard automated perimetry is the current gold standard for visual field examination, but not always suited for the evaluation of the VF in neurologically impaired patients. Pupil perimetry consists of the measurement of pupillary responses to light stimuli as a measure of visual sensitivity. What is new This study reports the highest diagnostic accuracy of pupil perimetry so far in patients with homonymous hemianopia. Gaze-contingent flicker pupil perimetry reliably and consistently measures defects in homonymous hemianopia under standard and virtual reality viewing conditions.

Phase-field modeling of lithium dendrite deposition process: When an internal short circuit occurs

Lithium dendrite growth is the main trigger for internal short circuits (ISC) of lithium-ion batteries. This paper investigates the lithium dendrite growth during the whole short circuit evolution process. In this paper, the lithium dendrite growth is divided into the initial deposition of the initial operation and the secondary deposition due to the internal short circuit. Firstly, a two-dimensional model based on the phase-field theory is developed and the growth in static electrolyte is investigated. Secondly, we summarize the whole evolution process and analyze the internal structural changes as well as the external features due to the internal short circuit. Based on this analysis, a model of secondary deposition in a flowing electrolyte is proposed. The model takes into account the effect of the flowing electrolyte on the dendrites. Finally, we investigate the growth of dendrites during secondary deposition. Due to an internal short circuit that damages the separator, a flowing electrolyte appears around the damaged region. This flowing electrolyte leads to uneven growth of dendrites, with “splitting” and “branch inhibition”. This phenomenon will accelerate the continued deposition of dendrites and induce a secondary internal short circuit. This work provides a quantitative simulation model for dendrite growth when an ISC occurs. Moreover, it also provides a reference for designing the structure of liquid batteries with high cycle times and safety.

Enhanced damage segmentation in RC components using pyramid Haar wavelet downsampling and attention U-net

Damage identification in post-earthquake reinforced concrete (RC) structures based on semantic segmentation has been recognized as a promising approach for rapid and non-contact damage localization and quantification. In damage segmentation tasks, damage regions are often set against complex backgrounds, featuring irregular geometric boundaries and intricate textures, posing significant challenges to model segmentation performance. Additionally, the absence of public datasets exacerbates these challenges, hindering advancements in this field. In this paper, a pyramid Haar wavelet downsampling attention UNet (PHA-UNet) semantic segmentation network is proposed, and a database containing 1400 images of damaged RC components (PEDRC-Dataset) with pixel-level annotations is established. In the proposed PHA-UNet, attention mechanisms, multiscale feature fusion, Haar wavelet downsampling, and transfer learning are introduced to address above challenges. Finally, the proposed PHA-UNet is compared with four existing image segmentation architectures on both the Cityspace and the PEDRC-Dataset.

Damage effects of KDP crystals induced by nanosecond laser

Abstract The surface morphology, compositions, microstructures, and chemical bond vibrations of potassium dihydrogen phosphate (KDP) crystals induced by nanosecond laser with different wavelengths, at different energy density are studied by scanning electron microscopy (SEM) and infrared spectroscopy (IR) techniques. SEM results showed that with the increase of laser energy density, the damage region on KDP surfaces presented three parts evidently. And the damage area increases nonlinearly with the laser energy density, accompanied by an increase in O element contents and a decrease in P and K element contents. Meanwhile, at the same energy density, the damage area induced by the 355 nm nanosecond laser is much larger than that by the 1064 nm nanosecond laser. Infrared spectrum results revealed that the laser irradiation leads to a break in hydrogen bonds and a dehydration of KDP crystals, in conjunction with a generation of P=O and P-H bonds. Moreover, with the increase of the laser energy density, the KDP crystal is damaged firstly, and then is annealed and repaired, finally is destroyed again. In addition, after irradiation at 10 J/cm2, all vibration modes of KDP crystals weaken or even disappear, and the sever damage occurs.

Numerical studies of one-way Lamb and SH mixing method in composite laminates with transverse-isotropic quadratic nonlinearity

Abstract The resonant behavior of one-way Lamb and SH (shear horizontal) mixing method in composite laminates with transverse-isotropic quadratic nonlinearity is investigated through numerical simulations in this paper. Different from previous studies, the composite constitutive model is combined from orthotropic elasticity and transverse-isotropic quadratic nonlinearity, which is implemented by ABAQUS/VUMAT subroutine. When two fundamental waves (S 0-mode Lamb waves and SH 0 waves) mix in composite laminates with quadratic nonlinearity, the resonant SH 0 waves can be generated with the resonance condition ω S 0 /ω SH 0 = 2 κ/(κ + 1). Meanwhile, the relationships between the acoustic nonlinear parameter (ANP) and damage degree, fundamental frequency, frequency deviation, propagation distance are also investigated. Moreover, the method of locating the damage region in composite laminates is proposed and verified by using the resonant wave time-domain signal.

Regenerating enteric neurites navigate the adult intestine using a glial positioning system?

While the enteric nervous system (ENS) is highly dynamic during development, the extent to which it is capable of repair remains unclear. In this issue of Neuron, Stavely etal.1 show that enteric neurons can reinnervate damaged regions to regain functionality using a glial positioning system (GPS) as their guide.

Spectrally distinct pixel extraction and kernel filtering for brain tumour diagnosis

Before surgery, medical segmentation is carried out to ascertain the limits of regions of interest (ROI). Critical information may be gathered during the planning phase of the operation if it is permitted that the growth, structure, and behaviour of the ROI be studied. This will increase the probability that the operation will be successful. Most of the time, segmentations are carried out either manually or via machine learning algorithms based on hand annotations. The difference between pure background information and an approximation of such information would affect the performance of brain tumour detection algorithms. This paper offers a technique for the identification of tumour regions that is based on kernel background filtration. The proposed approach presented has a more precise estimation of background information as its primary objective. It is composed of four stages. The first stage includes a probabilistic method based on image denoising. The second stage includes extracting the pure background pixels using a kernel-based technique. The third stage estimates the background covariance matrix using the pixels taken from the pure background pixels. In the fourth phase, we perform segmentation using DCNN. The segmentation procedure begins with training a deep convolutional neural network (DCNN) to recreate damaged brain regions. Window-based methods identify pixels with the largest reconstruction loss. This study isolates tumorous regions using pixel-wise segmentation. The proposed method segments tumours of various sizes with an average Dice score of 0.82.

An Improved YOLOv7 Model for Surface Damage Detection on Wind Turbine Blades Based on Low-Quality UAV Images

The efficient damage detection of the wind turbine blade (WTB), the core part of the wind power, is very improtant to wind power. In this paper, an improved YOLOv7 model is designed to enhance the performance of surface damage detection on WTBs based on the low-quality unmanned aerial vehicle (UAV) images. (1) An efficient channel attention (ECA) module is imbeded, which makes the network more sensitive to damage to decrease the false detection and missing detection caused by the low-quality image. (2) A DownSampling module is introduced to retain key feature information to enhance the detection speed and accuracy which are restricted by low-quality images with large amounts of redundant information. (3) The Multiple attributes Intersection over Union (MIoU) is applied to improve the inaccurate detection location and detection size of the damage region. (4) The dynamic group convolution shuffle transformer (DGST) is developed to improve the ability to comprehensively capture the contours, textures and potential damage information. Compared with YOLOv7, YOLOv8l, YOLOv9e and YOLOv10x, this experiment’s results show that the improved YOLOv7 has the optimal detection performance synthetically considering the detection accuracy, the detection speed and the robustness.

Single-event burnout in β-Ga2O3 Schottky barrier diode induced by high-energy proton

Single-Event Burnout (SEB) can cause hard damage to devices, leading to permanent failure. However, previous studies have rarely explored the effects of high-energy proton irradiation-induced SEB in β-Ga2O3 Schottky Barrier Diode (SBD), and the underlying mechanisms remain largely unexplored. Experimental results indicate that the reverse bias voltage during irradiation is a critical factor influencing the failure of β-Ga2O3 SBD. Compared to 300 MeV proton irradiation without bias, the introduction of a 300 V reverse bias voltage results in a significant reduction in forward current density (JF). When the reverse bias voltage reaches 400 V or higher, the 300 MeV proton induces SEB in the device. The SEM image of the damaged region reveals that the irradiated device has “voids” formed due to the melting of the Ga2O3 material. Geant 4 and TCAD simulation results indicate that the burnout phenomenon is caused by the elevated lattice temperature inside the device, which results from the implantation of secondary particles under a high reverse bias voltage. As the reverse bias voltage increases, the maximum lattice temperature of β-Ga2O3 SBD also rises. When the reverse bias voltage is sufficiently high, the local lattice temperature inside the device reaches the melting point of Ga2O3 material, ultimately leading to SEB.

Utilizing high-resolution 3D Voronoi meshing to analyze field data from the Brine Availability Test in Salt (BATS)

Salt is an attractive disposal medium for radioactive waste because intact salt is essentially impermeable and non-porous. However, upon drift or borehole excavation a damaged region develops surrounding the excavation which causes increased permeability and porosity creating potential flow paths for brine. Brine leads to corrosion of waste forms and waste packages and is a possible transport vector for radionuclides, so it is important to better understand the early-time behavior and evolution of brine flow in a salt. As a result, this study is part of Task E of DECOVALEX-2023 which focuses on understanding the evolution of thermal, two-phase hydrological, and mechanical processes in the excavation damaged zone in salt. Field measurements from The Brine Availability Test in Salt (BATS) 1a heater experiment are analyzed by implementing a high-resolution three-dimensional numerical model. This salt heater experiment consists of 28 days of heating and 13 days of cooling in a central borehole within bedded salt at the Waste Isolation Pilot Plant (WIPP). Here, the flow simulator PFLOTRAN is utilized; simulations are run on a Voronoi mesh, with temperature-dependent thermal conductivity, permeability and porosity decay away from excavations. The temperature-dependency of permeability is done to match field measurements. Results from the simulation match temperature measured in the field within + /- 0.1 °C and the total brine inflow over the 41-day experiment. This study illustrates that the accuracy of the temperature evolution within salt is critically important when analyzing and modeling experimental data by simulating three heating scenarios of the BATS 1a experiment showing that temperature has a direct effect on total brine inflow.

Embedded finite element modeling of the mechanics of brain axonal fiber tracts under head impact conditions

Investigating and understanding the biomechanical kinematics and kinetics of human brain axonal fibers during head impact process is crucial to study the mechanisms of Traumatic Axonal Injury (TAI). Such a study may require the explicit incorporation of brain fiber tracts into the host brain in order to distinguish the mechanical states of axonal fibers and brain tissue. Herein we extend our previously developed human head model by using an embedded element method to include fiber tracts reconstructed from diffusion tensor images in a host brain with the purpose of numerically tracking the deformation state of axonal fiber tracts during a head impact simulation. The updated model is validated by comparing its prediction of intracranial pressures with experimental data, followed by a thorough study of the effects of element types used for fiber tracts and the stiffness ratios of fiber to host brain. The validated model is also used to predict and visualize the damaged region of fiber tracts during the head impact process based on different injury criteria. The model is promising in tracking the state of fiber tracts and can add more objective functions such as axonal fiber deformation if used in the future design optimization of head protective equipment such as a football helmet.