Damaging Effects Research Articles

Ultrasonic guided wave damage localization method for composite fan blades based on damage-scattered wave difference

Abstract Ultrasonic guided wave (UGW) has a wide monitoring range and high accuracy, holding promise for monitoring damage in engine large-area composite fan blades. However, the multi-curvature characteristics of engine composite fan blades with their anisotropic material properties make damage localization impossible with conventional UGW monitoring methods. In order to realize the UGW damage monitoring of the blade, this paper proposes a damage localization method based on damage-scattered wave difference. The method utilizes irregular sensing arrays to achieve localization of damage in multi-curvature composite blades with a small amount of data. First, the difference between the mutual excitation in a pair of sensors and the damage-scattered waves captured at reception was analyzed. It is concluded that the closer the damage is to the received sensor, the greater the damage index (DI). Next, a DI ratio of the mutually excited and received signals is computed for each sensor pair. This ratio is utilized to make a vertical line on the propagation path, which is identified as the damage likelihood line (DLL). Finally, a DLL corresponding to the three largest DIs was selected, and their intersections were used for damage localization. A time-domain truncated signal processing method is proposed to enable DI to more accurately represent the effects of damage, and improve the localization accuracy of the method. An experiment on damage localization was carried out on a homemade composite fan blade, where the damage was tested at various locations and sizes. The results show that the damage localization on the blade is good and 3mm tiny damage localization is achieved.

Salidroside prevents cadmium chloride-induced DNA damage in human fetal lung fibroblasts

BackgroundCadmium (Cd) is an environmental pollutant and a heavy metal known for its genotoxic effects, which can lead to cancer and other related diseases. Preventing Cd-induced genotoxicity is crucial; however, there is limited research on this topic. Salidroside (SAL), a phenylpropanoid glycoside isolated from Rhodiola rosea L., is a popular medicinal compound with several health benefits. Nevertheless, its therapeutic effect on Cd-induced genotoxicity remains unexplored. MethodsHuman fetal lung fibroblasts were treated with 20 μM Cd2+ (CdCl2) for 12 h and 5–20 μM SAL was used to test the anti-DNA damage effect. DNA damage was evaluated using γH2AX expression and the alkaline comet assay. Intracellular reactive oxygen species (ROS) levels were measured using flow cytometry. ResultsExposure to 20 μM Cd2+ for 12 h induced significant DNA damage in human fetal lung fibroblasts, and this effect was notably attenuated by SAL treatment. SAL treatment did not decrease ROS levels in cells treated with Cd2+. ConclusionSAL effectively prevented Cd2+-induced DNA damage in human fetal lung fibroblasts. However, the underlying mechanism requires further investigation.

Experimental and numerical study on explosion resistance of polyurea-coated shelter in petrochemical industry

To reduce the number of casualties in explosion accidents, blast-resistant shelters can be used to protect personnel in high-risk areas of petrochemical processing plants. In this work, the deformation behaviours of uncoated and polyurea-coated blast-resistant plates were studied through gas explosion tests. An ANSYS/LS-DYNA model of a polyurea-coated shelter was established, and the dynamic responses of the shelter under various explosion loads were analysed. A series of fuel–air explosion tests were carried out to investigate the explosion resistance of the full-scale shelter. The results showed that compared with the uncoated blast-resistant plate, the deformation of the polyurea-coated blast-resistant plate was significantly reduced. The overall deformation of the shelter was the central depression of the wall and the inward bending of the frame. The damage effect of a typical high-overpressure, low-duration load was greater than that of typical low-overpressure, long-duration load. The shelter remained intact under three repeated explosive loads, with cracks appearing on the inner wall but no collapse or debris splashing. The shock wave attenuation rate of the shelter reached over 90%, which could significantly reduce the number of indoor casualties.

Neurotropic Effect of Botulinum Toxin and the Potential of Specific Serum Therapy in Botulism (Review)

INTRODUCTION. The outbreak of foodborne botulism that occurred in Russia in June 2024 once again demonstrated the danger of this rather rare but severe infectious disease caused by ingesting botulinum neurotoxin. The only aetiological treatment for botulism is currently the administration of antitoxins against various serotypes of botulinum toxin. However, antitoxins do not provide rapid regression of neurological symptoms, which may raise doubts about the effectiveness of the selected treatment option. It is impossible to assess the potential of specific treatment without understanding the mechanisms of action of botulinum toxin and antitoxin.AIM. This study aimed to systemise information on the mechanism underlying the damaging effect of botulinum neurotoxin, aetiological antitoxin treatment, and the patient recovery process.DISCUSSION. The mechanism underlying the damaging effect of botulinum neurotoxin consists in the destruction of SNARE proteins in presynaptic cholinergic nerve terminals, which disrupts the release of acetylcholine into the synaptic cleft and the transmission of excitation between neurons. The lack of acetylcholine at the neuromuscular junction results in a distinctive form of persistent flaccid paralysis. The specific mechanism of action of botulinum toxin determines the treatment strategy, which includes a set of life-sustaining measures and the earliest possible antiserum administration. If used within 48 hours from the onset of symptoms, botulinum antitoxin binds botulinum toxin circulating in the blood, which stops the progression of paralysis and prevents further disorders in patients. However, botulinum antitoxin cannot neutralise the effect of the toxin that has already bound to nerve receptors, so clinical symptoms may worsen within 12 hours after antiserum administration. Restoration of normal neuronal transmission occurs through the formation of new axonal sprouts and can take a long time.CONCLUSIONS. Antitoxin administration is effective and irreplaceable in the aetiological treatment of botulism. Nevertheless, the duration of recovery depends on the speed of reinnervation and restoration of transmission at the neuromuscular junction.

Melatonin attenuates affective disorders and cognitive deficits induced by perinatal exposure to a glyphosate-based herbicide via antioxidant pathway in adult male and female rats.

The massive use of herbicides, particularly glyphosate-based herbicides (GBHs), raises several worries, notably their neurotoxic effects. Several studies have explored the consequences of developmental exposure. Our work aims to determine the impact of maternal exposure to GBH on behavioral disorders and memory deficits, as well as the involvement of oxidative stress in the hippocampus and prefrontal cortex. In addition, our study explores the neuroprotective properties of melatonin in male and female offspring. Pregnant Wistar rats were injected with GBH 75 mg/kg during gestation and lactation. After weaning, the offspring were treated with melatonin (4mg/kg) from postnatal days 30-58. Our results show that GBH increases anxiety-like behavior levels in offspring, as well as depression-like behavior. GBH also impairs working memory in progeny. While markers of oxidative stress show a disturbance in lipid peroxidation and catalase activity, with a more pronounced effect in females, on the other hand, melatonin considerably attenuated the neurotoxic impact observed in the offspring, with higher efficacy in females. The oxidative stress results confirm the antioxidant power of melatonin to counteract the damaging effects of exposure to environmental contaminants such as glyphosate-based pesticides. It will then be interesting to further our work to fully understand the sex-dependent effect of melatonin.

Experimental research of corroded concrete beams with natural cooling after fire considering the bond deterioration

The residual bearing capacity after fire is of great significance for safety assessment and repair of building structures. To accurately evaluate the residual strength of corroded beam after natural cooling, this study investigated the residual bearing capacity of corroded beam considering the bond deterioration after fire exposure. First, the bond behavior and flexural-deformation capacity was conducted by pullout test and bending test after corrosion erosion and fire temperatures damage. The bond deterioration test shows that when the temperature rises above 200℃ and the corrosion level exceeds 4.3%, the bond strength decreases by 16.5%. At the temperature reaches 600℃ or the corrosion degree reaches 13.8%, the bond behavior damage exceeds 50%. The bending test indicates that corrosion and high temperature damage both decrease the bending bearing capacity of the beam, but the influence of high temperature damage on the residual bearing capacity is greater than that of corrosion. The bond property deterioration decreases the strain value of the tensile rebar during the bending process, and decreases the bending capacity of the beam. Finally, a bond-slip constitutive model suitable for corroded beams after fire is proposed, which is applied to the calculation of the ultimate moment of the beam. The modified value of beam bearing capacity considering bond deterioration has better collimation and higher safety margin. The bond-slip constitutive model and the modified calculation method of bending moment of beam are helpful to provide more accurate performance assessment of beam after the coupling effect of corrosion and fire damage.

Experimental behaviour and fatigue life prediction of bonded joints subjected to variable amplitude fatigue

The variable amplitude fatigue behaviour of adhesive joints has not been extensively considered in literature and considerable knowledge gaps regarding its underlying mechanisms still exist, hindering accurate life prediction. This study investigates the effect of loading sequence and number of load transitions on single lap joints (SLJs) bonded with a toughened epoxy adhesive. Life prediction is also conducted using established cumulative rules: Palmgren–Miner (PM), Broutman and Sahu (BS) and, Hashin and Rotem (HR). To overcome their limitations, a modified Cortan–Dolan approach is proposed. For this, SLJs were subjected to single transition (low-to-high and high-to-low load transitions at different stages of the fatigue life and with different magnitudes) and multi-block loading spectra with different numbers of transitions.Results showed an extension of the fatigue life for high-to-low transitions. This was attributed to a combination of load interaction effects, as evidenced by an elastoplastic numerical simulation, and non-linear damage accumulation. Conversely, low-to-high transitions exhibited a damaging effect. For single transition spectra, BS and HR models were seen to improve prediction over PM by indirectly considering these effects. The proposed approach further improved this prediction. Multi-block results showed no significant influence of the number of load transitions and were satisfactorily predicted using PM.

The effect of vitamin D3 and omega-3 combination, taken orally, on triglycerides, lining of intestine, and the biodiversity of gut microbiota in healthy rats.

The gut microbiota plays a key role in host health. An intake of omega-3 and vitamin D3 in a separate manner is vital for maintaining good health of gut microbiota and controlling some illness manifestations. The aim of this study is to investigate the potential change in biodiversity of the gut microbiome in healthy rats supplemented with vitamin D3, omega-3 alone and their combination and to reflect onto the triglyceride levels in serum and fecal samples. Using the 16S rRNA gene Miseq Illumina NGS, and monitoring triglyceride levels in serum and fecal samples coupled with several clinical parameters, we examined the effect of orally taken combination of omega-3 and vitamin D3 alongside the separate intake of supplements on gut microbiota in 24 healthy white Wistar rats for six weeks. The study findings showed that combination treatment encouraged the growth of opportunistic Clostridia class during day 21 and 42 of treatment by 7.7 and 7.4 folds, respectively, exhibited incomplete absorption levels for both supplements when used concomitantly, demonstrated a damaging effect on the gut intestinal lining wall thickness (126 µm) when compared to control group (158 µm), increasing lumen diameter (400 µm), and showed higher triglyceride level in fecal samples. These findings indicate that omega-3 and vitamin D3 supplements as combination intake reveal unfavorable effects, thus, it is advised to conduct further in-depth studies to clarify the presence or absence of any chemical interaction between both supplements' molecules and to investigate based on human model to attain a superior perspective.

Effect of machining damage on the surface roughness and flexural strength of CAD-CAM materials

Computer-aided design and computer-aided manufacturing (CAD-CAM) materials are available for different types of restorations. However, the longevity of the material is affected by chipping, milling damage, flexural strength, and surface roughness, and a standard edge chipping test or standardized measurements are unavailable for monitoring edge chipping of rotary instrument-milled materials. The purpose of this in vitro study was to analyze the surface roughness and edge chipping of different CAD-CAM diamond rotary instrument-milled dental material bars, correlate the effect of machining damage with material strength, and compare the flexural strength of rotary instrument-milled and sectioned CAD-CAM blocks. Five dental CAD-CAM materials were tested: lithium disilicate glass-ceramic (IPS e.max CAD), leucite-reinforced glass-ceramic (IPS Empress CAD); feldspathic porcelain (Vitablocs Mark II); feldspar ceramic-polymer infiltrated (Enamic), and composite resin (Lava Ultimate). Rectangular bars were designed and milled for each material (n=10). The surface roughness of the bars was measured using a profilometer. All edges of 3 selected bars were analyzed with scanning electron microscopy (SEM) for the chip length, depth, and area. The 3-point bend test was used to test the flexural strength of rotary instrument-milled and saw-cut bars with the same dimensions. Analysis of variance and the Tukey honestly significant difference post hoc test were used to determine the difference among the groups (α=.05). IPS e.max CAD had the highest surface roughness and Lava Ultimate the lowest. Lava Ultimate had the smallest chipping factor and IPS Empress CAD the largest. The surface location significantly affected the chipping depth, area, and length (P<.05). A strong correlation was found between the decrease in flexural strength and the chipping length on the central tensile side of the rotary instrument-milled materials (R2=.62, P=.01), as well as the chipping depth (R2=.44, P=.01). Edge chipping was significantly associated with the material type, milling surface, and edge location and strongly correlated with a decrease in flexural strength.

Саморегулівні організації: юридичні особи на межі приватного і публічного права

The article analyses the legal status of self-regulatory organisations (SROs). These organisations are formed among the actors of various types of professional and business activity (lawyers, doctors, auditors, accountants, etc.), but the notion ‘self-regulatory organization’ has started to be used in legislation only recently. The main function of these organisations is to carry out self-regulation, i.e. to regulate the activity of their own members by adopting rules of conduct and monitoring compliance with them. However, these organisations often acquire regulatory powers not only from their members, who voluntarily agree to be subject to their regulation, but also from the state, which delegates to them or recognizes their public regulatory powers. This creates a kind of paradox: on the one hand, SROs are established in a manner typical of private law entities. However, on the other hand, their activities acquire the features of administrative activity. This raises a number of issues in law enforcement practice. Firstly, there are difficulties with the type of legal regulation that should be applied to the activities of these organisations - general permissive or special permissive. Secondly, the issue of court jurisdiction is ambiguous as well, i.e. which courts (administrative or commercial) have competence to resolve disputes arising between self-regulatory organisations and their members. Thirdly, the issue of compulsory membership in self-regulatory organisations is also quite acute, as this may lead to a violation of the right to freedom of association. Finally, the question of whether SROs are liable in the event of damage caused by them when exercising public authority is also ambiguous. There is a question concerning the conditions of their liability: shoud these be general conditions (Articles 1166-1167 of the Civil Code of Ukraine) or special conditions according to the rule of ‘truncated’ composition, which is typical for the liability of public authorities (Article 1173 of the Civil Code of Ukraine). This article provides a detailed analysis of these and other issues and outlines the ways to resolve them

NIR-driven intense UV upconversion films for non-contact high-efficiency prevention of bacterial infections

Bacterial infections on wounds imposes a significant limitation to the wound healing. Although the conventional drug antibacterial dressing is employed for hindering bacterial infection, the inevitable microbial resistance and secondary damage severely limit the quality and speed of wound healing. Herein, the NIR-driven intense UV upconversion (UC) BaLu2F8:80%Yb3+/0.5%Tm3+ microcrystals are, for the first time, designed and fabricated into solid sterilization film to protect the wounds from infections. Equipped with excessive Yb3+ sensitizers, the emission of Yb3+/Tm3+ co-doped monoclinic BaLu2F8 matrix achieve a 175-fold enhancement at the UV band. The UV UC microcrystals was further fabricated into a NIR-to-UV sterilization film with a diameter of 1.5 cm and a thickness of 150 μm using solution casting method, which can efficiently destroy 97 % of E. coli with a NIR irradiation of 5 minutes. Due to the outstanding penetrability of NIR irradiation, the sterilization film under 4 layers gauze dressing can be activated to produce UV photons. The in-vivo mouse tests demonstrate the well-designed NIR-to-UV sterilization film can speed up the wound healing by high-efficient inhibiting E. coli infection under the irradiation of 980 nm NIR laser. The non-contact NIR-driven UV sterilization film require no more drugs and dressing exchange, thus entirely eliminating the effect of microbial resistance and secondary damage from conventional drug dressing. Our work provides a new alternative for constructing highly-efficiency sterilization dressing through the utilization of NIR-to-UV optical conversion materials.

A study of the effects of arc damage from aviation faults

A study of the effects of arc damage from aviation faults

Clarifying the effect of irradiation and thermal treatment on the austenitic microstructure and austenitic hardening in austenitic stainless steel weld metal

The weld cladding on the inner surface of nuclear pressure vessels due to irradiation damage and thermal effect presents to a safety issue. Unfortunately, the effect of irradiation and long-term thermal treatment on the austenitic microstructure and austenitic hardening in austenitic stainless steel weld metals (ASSWMs) remains poorly understood. In this study, the effects of irradiation and thermal treatment on the austenitic microstructures and austenitic hardening of 308L ASSWMs were investigated using nanoindentation, atom probe tomography and transmission electron microscopy. The results suggested that irradiation resulted in the formation of Ni/Si-rich clusters, voids, and Frank loops in austenite, thereby inducing austenitic hardening. Subsequently, thermal treatment decreased the size and the number of Frank loops in irradiated austenite, which had a minor effect on austenitic hardening. However, thermal treatment promoted the growth of Ni/Si-rich clusters and void formation, which have a primary effect on austenitic hardening, thereby enhancing the hardening of irradiated austenite. Furthermore, thermal treatment has little effect on the microstructure and hardening of austenite. Then, irradiation promoted the formation of Ni/Si-rich clusters, voids, and Frank loops in thermally treated austenite, resulting in austenitic hardening. The interaction of irradiation and thermal treatment can promote the formation of voids. The austenitic hardening was mainly due to the contribution of Frank loops, voids, and Ni/Si-rich clusters, which acted as short-range barriers by pin-moving dislocations.

Cellular and Molecular Mechanisms of Neuronal Degeneration in Early-Stage Diabetic Retinopathy.

Studies on the early retinal changes in Diabetic Retinopathy (DR) have demonstrated that neurodegeneration precedes vascular abnormalities like microaneurysms or intraretinal hemorrhages. Therefore, there is a growing field of study to analyze the cellular and molecular pathways involved to allow for the development of novel therapeutics to prevent the onset or delay the progression of DR. Molecular Mechanisms: Oxidative stress and mitochondrial dysfunction contribute to neurodegeneration through pathways involving polyol, hexosamine, advanced glycation end products, and protein kinase C. Potential interventions targeting these pathways include aldose reductase inhibitors and protein kinase C inhibitors. Neurotrophic factor imbalances, notably brain-derived neurotrophic factor and nerve growth factor, also play a role in early neurodegeneration, and supplementation of these neurotrophic factors show promise in mitigating neurodegeneration. Cellular Mechanisms: Major cellular mechanisms of neurodegeneration include caspase-mediated apoptosis, glial cell reactivity, and glutamate excitotoxicity. Therefore, inhibitors of these pathways are potential therapeutic avenues. Vascular Component: The nitric oxide pathway, critical for neurovascular coupling, is disrupted in DR due to increased reactive oxygen species. Vascular Endothelial Growth Factor (VEGF), a long-known angiogenic factor, has demonstrated both damaging and neuroprotective effects, prompting a careful consideration of long-term anti-VEGF therapy. Current DR treatments primarily address vascular symptoms but fall short of preventing or halting the disease. Insights into the mechanisms of retinal neurodegeneration in the setting of diabetes mellitus not only enhance our understanding of DR but also pave the way for future therapeutic interventions aimed at preventing disease progression and preserving vision.

REACTION OF LYMPHOID TISSUE IN THE WALL OF THE DUODENUM AND LYMPHOID PLAQUE IN RATS IN MODELING HYPOKINESIA

The damaging effect of hypokinesia on the functional state of lymphoid tissue in the wall of the duodenum and on the lymphoid plaque was established. It was found that the processes of cell destruction, suppression of the plasma reaction and blast transformation of cells are most pronounced in the wall of the duodenum. In the lymphoid plaque, along with a high level of destructive processes in lymphoid cells, lymphocytopoiesis is preserved in the centers of proliferation of lymphoid nodules and the proportion of plasma cells increases in the internodal zone, which indicates the development of compensatory processes under the long-term influence of hypokinesia.

Synonymous rpsH variants: the common denominator in Escherichia coli adapting to ionizing radiation.

Ionizing radiation (IR) in high doses is generally lethal to most organisms. Investigating mechanisms of radiation resistance is crucial for gaining insights into the underlying cellular responses and understanding the damaging effects of IR. In this study, we conducted a comprehensive analysis of sequencing data from an evolutionary experiment aimed at understanding the genetic adaptations to ionizing radiation in Escherichia coli. By including previously neglected synonymous mutations, we identified the rpsH c.294T > G variant, which emerged in all 17 examined isolates across four subpopulations. The identified variant is a synonymous mutation affecting the 30S ribosomal protein S8, and consistently exhibited high detection and low allele frequencies in all subpopulations. This variant, along with two additional rpsH variants, potentially influences translational control of the ribosomal spc operon. The early emergence and stability of these variants suggest their role in adapting to environmental stress, possibly contributing to radiation resistance. Our findings shed light on the dynamics of ribosomal variants during the evolutionary process and their potential role in stress adaptation, providing valuable implications for understanding clinical radiation sensitivity and improving radiotherapy.

Hepatoprotective Effect of Ethanolic Pomegranate Peel Extract Against Levofloxacin via Suppression of Oxidative Stress, Proinflammation, and Apoptosis in Male Rats.

One of the fluoroquinolone antibiotics, levofloxacin (LEV), is used to treat a variety of illnesses leading to oxidative stress and cellular damage. Peel from Punica granatum is a waste product abundant in phytochemicals with various biological activities. This study aimed to evaluate P. granatum peel extract's (PGPE) potential to mitigate oxidative stress, inflammation, apoptosis, and liver damage caused by LEV. There were four groups of rats: control, PGPE, LEV, and PGPE + LEV, respectively, and they were orally administered their daily treatments for 2 weeks. Results revealed that PGPE has a large number of phytochemical components with high antioxidant activity. PGPE intake alone enhanced the antioxidant status and decreased oxidative stress. On the other hand, pretreatment of the LEV group with PGPE restored oxidative stress, antioxidant enzymes, glutathione content, liver function biomarkers, and hematological parameters. Also, normalization of gene expressions (cyclooxygenase-2, transforming growth factor-beta1, caspase-3, heme oxygenase-1, B cell lymphoma-2, interleukin [IL]-10, and IL-1) and improvement in liver architecture, and immunohistochemical alpha-smooth muscle actin, were seen in comparison to the LEV group. Conclusively, PGPE exhibits strong anti-inflammatory, antiapoptotic, and antioxidant properties that shield rat liver from the damaging effects of LEV and offer a fresh viewpoint on the application of fruit waste products.

Impact of proton radiation and annealing of CMOS image sensors on star sensor performance

Star sensors play a crucial role as high-precision optical attitude navigation devices in satellite attitude control systems. The CMOS image sensor is an important component of the imaging system of the star sensor and experiences performance degradation due to the total ionizing dose effect and displacement damage effect in the radiation environment of its long-term operational workspace. As a result, the detection capability and attitude positioning accuracy of the star sensor gradually deteriorate. The performance of CMOS image sensors can be partially restored after annealing but the impact on the performance of star sensors is unclear. This study conducted 100 MeV proton irradiation experiments with different fluences on CMOS image sensors and performed room temperature and high temperature annealing treatments. By testing and analyzing the performance of star sensors equipped with irradiated and different annealing treatments on CMOS image sensors, the impact mechanism of CMOS image sensor radiation damage and annealing recovery on the performance variation of star sensors was obtained. This study provides theoretical support for reliability of long-term in-orbit star sensors.

A damage effectiveness evaluation approach of warhead fragment group on missile target based on intuitionistic fuzzy neural network

A damage effectiveness evaluation approach of warhead fragment group on missile target based on intuitionistic fuzzy neural network

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.