Damage Index Research Articles

Анализ взаимосвязи показателей цитогенетического и психофизиологического статуса персонала при сочетанном действии факторов производственной деятельности

Background: Analysis of the Relationship of biomarkers of Cytogenetic and Psychophysiological Status (CGS and PPS) of personnel under conditions of the combined influence of occupational factors. Material and methods: CGS was determined using a non-invasive Buccal Micronucleus Cytome Assay (BMCA) and determination of the accumulation index of cytogenetic damage and the level of cytogenetic stress. PPS of personnel was determined in accordance with MR 2.2.9.84 – 2015 FMBA of Russia and the Health-Test program. Results: People with average and high levels of psychophysiological adaptation have a low level of cytogenetic damages. Also, in the group with a high accumulation index of cytogenetic damages a low level of psychophysiological adaptation was determined. Conclusion: An increased level of cytogenetic damages has been established in people with a low level of psychophysiological adaptation. Taking into account the literature data, we can assume an indirect dependence of the cytogenetic status of the organism on its psychophysiological adaptation, which may be due to hormonal imbalance and the induction of oxidative stress.

Mitochondria as Sensors of Amyloid‐Beta Toxicity and Regulators of Inflammation in Cerebrovascular Endothelial Cells

AbstractBackgroundThe blood‐brain barrier (BBB) is a crucial regulator of cerebral homeostasis and function. Cerebrovascular endothelial cells (EC) are important components of the BBB, and EC damage and/or dysfunction may result in defects in brain clearance and perfusion, microhemorrhages, inflammation, and neurodegeneration. In addition to EC damage resulting from the presence of amyloid‐beta (Aβ) in Alzheimer’s Disease (AD) and Cerebral Amyloid Angiopathy (CAA), the presence of cardiovascular risk factors (CVRF) may further exacerbate cerebrovascular function and neurodegeneration. Particularly, ECs may be the most susceptible to Aβ and CVRF damage leading to the initiation and/or perpetuation of an inflammatory cascade in neurodegenerative diseases. Brain ECs are highly dependent on glycolysis and their mitochondria have important roles as signaling organelles, sensing cellular damage and mediating downstream pathways such as inflammation. Here, we aim to understand the mechanistic nature of endothelial mitochondrial dysfunction and its elicited pathways in Aβ and mixed (Aβ+CVRF) vascular pathologies. Understanding the mechanisms by which the mitochondria may mediate EC inflammation could pave the way to new roads for therapeutic advancements in the field.MethodHuman brain microvascular ECs were challenged with Aβ, Homocysteine (Hcy, a CVRF), or the combination. Mitochondrial ultrastructure, metabolic function, and inflammatory cascades were assessed.ResultThe presence of Aβ, but not Hcy, increased mitochondrial ROS production (mtROS) and induced deficits in mitochondrial respiration concomitant with a decrease in mitochondrial ATP production. Deficits in mitochondrial respiration were accompanied by an increase in glycolytic ATP production and, to some extent, the expression of proteins involved in glycolytic regulation. Mitochondrial fragmentation, as an indicator of mitochondrial damage, was assessed ultrastructually and by the analysis of the expression of fission proteins. Markers of EC activation were assessed to link mitochondrial dysfunction to EC inflammation.ConclusionDeficits in mitochondrial function and metabolism were associated with Aβ but not Hcy, and accompanied by the release of mtROS, a mitochondria damage associated molecular patterns (mtDAMP). This, in turn, was associated to an increase in EC inflammatory markers and barrier permeability. Overall, our results reveal a novel role for mtDAMPs in vascular dysfunction in the presence of Aβ and/or Hcy.

Seismic performance of compressed earth block walls reinforced with common reeds

Compressed earth block (CEB) is a sustainable and cost-effective option for eco-friendly constructions. The blocks are produced without burning fossil fuels and have low embodied energy. The abundance of its constituents, including clay and sand, is another merit. However, the susceptibility of CEB constructions against seismic forces is still considered a prominent hindrance to their widespread acceptance. The study aims to improve the in-plane seismic performance of CEB walls by using common reeds as a natural reinforcing material. For this purpose, seven wall panels with dimensions of 1000×900×120 mm3 were constructed. Seismic loading was simulated using an incrementally increasing lateral cyclic displacement combined with a constant vertical stress of 0.3MPa. The results are discussed in terms of the hysteresis load-displacement responses, displacement ductility, energy dissipation, and stiffness degradation. Based on laboratory experiments, the strength and lateral displacement of the reinforced specimen with four vertical reeds were increased by 44% and 76%, respectively, compared to the non-reinforced ones. Ultimately, Seismic assessments and damage indexes of the tested walls indicated that the in-plane seismic performance of CEB walls could be significantly improved by using vertical sand-coated reeds.

Forest Health Monitoring of Tree Collections in Bogor Botanical Garden: A Case Study of Plot V

Abstract Botanical Garden is an ex-situ plant conservation area with documented plant collections, especially species of scarce, endangered, and endemic species. Bogor Botanical Garden has 25 collection plots, and this research focused on collection plots V (V.A., V.B., and V.C.). The study aims to estimate the percentage of trees in healthy condition and the number and types of trees with severe tree damage. The method used is Forest Health Monitoring (FHM), which was done visually to identify the type and extent of tree damage. The results of the research showed that 234 trees fit into the healthy tree classification (86.67%) with NIK (damage index value) (0 ≤ 5) from the total number of trees observed, namely 270 trees in those collection plots. The tree classification for heavy damage was four trees (1.48%) (NIK 16 ≥ 21), including Barringtonia racemosa (L.) Spreng., located in collection plot V.A.078a, Syzygium aqueum (Burm.f.) Alston., which is in plot V.A.129, and Syzygium polycephaloides (C.B.Rob.) Merr., which is in plot V.B.111 and 111a. Most trees in plot V were healthy, but the least were heavily damaged.

Finite Element Analysis for Aluminium Alloy 7075-T6 Subjected to the Bending-Torsional Variable Phase of Fatigue Loading

In this study, the fatigue behaviour of the alloy structure of Aluminium alloy 7075-T6 is investigated numerically. Three main factors were taken into account when researching the alloy composition of aluminium alloy 7075-T6: life prediction, damage indicator, and Biaxiliray indexation. A prediction of life expectancy seems to be the most reliable indication. Experiments have been carried out with the stress totally inverted as the variable in order to determine whether or not the phenomena of exhaustion can be described by the theory proposed by GoodMan. It was determined that the dynamic load of 100 kilonewtons (kN) and 1100 nanometers (Nm) was used in order to produce estimates for these characteristics. In order to assist us in gaining a better understanding of these characteristics, it has approximated them by making use of the dynamic load that was applied. An increase in the main force to 100 kilonewtons would bring the expected lifetime up to 141 cycles, according to the findings of the computer research. In this regard, the findings of the inquiry provided evidence. The findings demonstrated that this is really the case. The Biaxiliray indexation obtained a value of 0.46 when subjected to the same stress conditions. The numerical results demonstrated that the damage is obvious during the first 10E32 cycles of stress, which is in addition to the research that have been conducted on damage indicators. These findings were demonstrated not just through theoretical study of the damage indicator but also via practical numerical data.

Near-real-time damage identification under vehicle loads using dynamic graph neural network based on proper orthogonal decomposition

Structural health monitoring (SHM) is essential for managing infrastructure by continuously monitoring performance. To address the complexity of SHM for large systems, this study introduces a dynamic graph neural network (DynGNN) approach for near-real-time damage identification. The approach represents the infrastructure as a graph and uses a dynamic adjacency matrix based on proper orthogonal decomposition (POD) to capture the dynamic characteristics and spatial correlations of responses. The DynGNN model has an autoencoder architecture with one encoder for latent feature extraction and two decoders for capturing spatiotemporal changes and is trained on intact structural responses. The proposed approach employs a damage index based on reconstruction errors for damage identification. In applications to a steel truss bridge under vehicle loads, the proposed approach is tested by real-time simulation using the field test data obtained from the damaged bridge. By incorporating a dynamic adjacency matrix, the results successfully demonstrate that the proposed approach effectively adapts to the time-varying nature of structural responses and can accurately identify damage in near-real time. The novel integration of a dynamic graph structure with POD allows the proposed method to capture both spatial and temporal variations, providing a significant improvement over traditional static methods.

Repercussions of Long-Term Naproxen Administration on LPS-Induced Periodontitis in Male Mice.

Chronic periodontitis is the sixth most prevalent disease worldwide and the leading cause of tooth loss in adults. With growing attention on the role of inflammatory and immune responses in its pathogenesis, there is an urgent need to evaluate host-modulatory agents. Non-steroidal anti-inflammatory drugs (NSAIDs) drugs play a crucial role in managing inflammatory conditions. This study examined the repercussions of long-term naproxen use in a periodontal inflammation model known for causing significant inflammation, disrupting epithelial and connective tissue attachment and leading to alveolar bone destruction. Thirty BALB/c mice were treated with naproxen for 60 days or left untreated. From Day 30, an LPS solution was injected into gingival tissues three times per week for four weeks. This model enables LPS control over the inflammatory stimulus intensity throughout the experimental period, leading to chronic inflammation development involving both innate and adaptive immunity. The liver, stomach and maxillae were submitted to histological analysis. The oxidative damage was determined by measuring lipid peroxidation (LPO) in plasma and gingiva. The activities of myeloperoxidase (MPO), eosinophil peroxidase (EPO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and levels of leukotriene B4, the interleukin (IL)-1β, TNF-α, IL-4, IL-5, IL-10, the chemokine CCL11 were also assessed in the gingival tissues. The results indicated that none of the groups displayed any indications of liver damage or alterations; however, the NPx treatment led to severe gastric damage. In contrast, the treatment alleviated periodontal inflammation, resulting in a reduction of chronic and acute inflammatory cell infiltration and prevention of connective tissue loss in the gingival tissue. Additionally, the treatment increased the activities of endogenous antioxidant enzymes SOD, CAT and GPx, as well as the IL-10 cytokine, while decreasing the levels of leukotriene B4, TNF-α, IL-4 and IL-5. Furthermore, the activities of MPO, EPO and LPO were reduced in the treated groups. These results suggest that NPx effectively inhibits periodontal inflammation in an inflammatory periodontal model. However, the harmful gastric effects dramatically limit its long-term use.

A direct energy-based design method for damping control reinforced concrete structure: methodology and application

Energy-based seismic design, which integrates both the accumulated hysteretic energy and plastic deformation of the structure, provides a more comprehensive evaluation of structural seismic performance compared to other performance-based seismic design methods. In damping control structures, the distribution of hysteretic energy is clearly defined, with the expected positions for energy dissipation and damage concentrated in the dampers. This facilitates the application of an energy-based design method in such structures. This research presented a novel direct energy-based design (DEBD) method for damping control reinforced concrete (RC) structures, following the principle that the energy dissipation capacity of the structural members and dampers exceeds the hysteretic energy dissipation demand. With this principle, an energy-based damage index, which is directly correlated with structural damage state, was introduced. Subsequently, a detailed energy-based design process was provided. To achieve the desired seismic performance, the required energy dissipation capacity of dampers was determined using a pre-select damage index, and thereby, identifying the design parameters of the dampers. Finally, to validate the feasibility of the proposed design method, an 8-story RC frame with friction dampers was chosen as an example. The energy dissipation capacity and damage state of the designed structure were evaluated through nonlinear time-history analyses, and the results demonstrate the successfully achievement of the predefined seismic performance.

Relationship Between Short-Term Blood Pressure Variability and Choroidal-Retinal Thicknesses Assessed by Optical Coherence Tomography in Hypertensive Subjects.

Background/Objectives: The complications of hypertension depend not only on the mean blood pressure (BP) but also on its variability (BPV). Recent studies suggest that the choroid may serve as an indicator of systemic vascular damage. These studies have been made possible by the increased availability of optical coherence tomography (OCT). The aim of our study was to analyze the relationship between short-term BP variability (STBPV) and choroid-retinal thickness in hypertensive patients. Methods: A total of 98 patients with a mean age of 49 ± 12 years were enrolled in the study. All participants underwent 24 h blood pressure (BP) monitoring to measure 24 h mean systolic (SBP) and diastolic blood pressure (DBP), along with their respective standard deviations (SD), the weighted SD of 24 h SBP and DBP, and the average real variability (ARV) of 24 h SBP and DBP. The choroid-retinal region was assessed using Swept-Source OCT, with choroidal thickness (ChT) and retinal thickness divided into three concentric rings, and their mean choroidal thickness (ChT-or) was calculated. Results: The choroidal thickness of the concentric rings was found to be inversely correlated with all ARV values of the monitored blood pressure means. In particular, a correlation was observed between the ARV of daytime DBP and ChT-or. This correlation remained statistically significant (β = -0.34; p = 0.02) even after adjustment for various confounding factors. The ARV of daytime DBP was the only STBPV index to maintain a significant association, in the multivariate analysis, with the central ring mean thickness (β = -0.314; p = 0.001) and the inner choroidal ring mean thickness (β = -0.262; p = 0.003). Conclusions: Our study demonstrated an independent negative association between short-term BP variability (STBPV), when expressed as ARV of daytime DBP, and choroidal thickness. This finding confirms the value of choroidal thickness as a marker of cardiovascular risk.

Experimental Study on Fatigue Properties of Q420 Bridge Steel in a Deicing Salt Corrosion Environment in Western China

The corrosive environment in the western region will adversely affect the fatigue performance of bridges. In order to determine the influence of the corrosion environment in western China on the fatigue failure of bridges, this paper simulated corrosion environment characteristics in northwest China, conducted alternating corrosion and high-cycle fatigue experiments on Q420 bridge steel, and used Origin (2019b 64Bit) to fit S-N curves of specimens with different corrosion periods to study the influence of corrosion damage in western China on their fatigue properties. Based on the damage theory, the corrosion fatigue failure degree of Q420 bridge steel was analyzed, and the crack propagation law was revealed by microscopic scanning of the fracture. The findings indicate that the damage to Q420 bridge steel progressively worsens with more prolonged corrosion exposure in the deicing salt conditions of western China. The 60-day corrosion resulted in a rust rate ηs of 2.17% and a corrosion rate K of 1.413 mm/a. The fatigue life of Q420 bridge steel is significantly affected by the coupling of stress level and corrosion damage. After 60 days of corrosion, the specimen’s fatigue limit decreases by 12.28%, which accelerates the fatigue property degradation rate of the specimen. The damage index effectively represents the internal damage behavior of materials under corrosion fatigue conditions. Fatigue damage escalates as the corrosion period extends, and the number of fatigue bands decreases, with the stress corrosion threshold σth diminishing by 1.77%, 3.55%, 4.61%, and 6.38% across various corrosion durations. The research results are significant for the fatigue failure prediction and reliability analysis of Q420 bridge steel in a deicing salt corrosion environment in western China.

A friction energy-based damage model for discrete element simulation of fatigue damage evolution in concrete

The discrete results of concrete fatigue tests limit the research of concrete fatigue theory. Numerical simulation methods can model the damage of materials from multiple scales, which helps to reveal the fatigue damage mechanism and compensate for the inadequacy of physical tests. This study presents a novel damage model for simulating the fatigue damage evolution of cementitious materials within the framework of discrete element methods. The proposed friction energy-based fatigue damage model is underpinned by a clear fatigue damage mechanism and has only two independent parameters. The model underwent validation through a comparison between its predictions and the results of compression cycle tests performed on concrete specimens. The model reproduces the evolution characteristics of various fatigue damage indicators, including deformation, modulus, hysteretic energy, and number of cracks, and the fatigue damage accumulation rate presents sensitivity to the stress level. Furthermore, the model predicts a clear regularity in the fatigue damage thresholds, which is an important reference value for establishing fatigue failure criteria. The model can be used to predict fatigue life of fatigue tests with various maximum and minimum stress levels and the S-N curves obtained from the simulations fall within the range of test results.

In-situ monitoring of µm-sized electrochemically generated corrosion pits using Lamb waves managed by a sparse array of piezoelectric transducers

Corrosion is a major threat in the aeronautic industry, both in terms of safety and cost. Efficient, versatile, and cost affordable solutions for corrosion monitoring are thus needed. Ultrasonic Lamb Waves (LW) appear to be very efficient for corrosion monitoring and can be made cost effective and versatile if emitted and received by a sparse array of piezoelectric elements (PZT). A LW solution relying on a sparse PZT array and allowing to monitor µm-sized corrosion pit growth on stainless 316L grade steel plate is here evaluated. Experimentally, the corrosion pit size is electrochemically controlled by both the imposed electrical potential and the injection of a corrosive NaCl solution through a capillary located at the desired pit location. In parallel, the corrosion pit growth is monitored in-situ every 10 s by sending and measuring LW using a sparse array of 4 PZTs bonded to the back of the steel plate enduring corrosion. As a ground truth information, the corrosion pit volume is estimated as the dissolved volume balancing the electronic charges exchanged during corrosion. The corrosion pit radius is additionally checked post-experiment precisely with an optical measurement. Measured LW signals are then post-processed in order to compute a collection of synthetic damage indexes (DIs). After dimension reduction steps, obtained DI values correlates extremely well with the corrosion pit radius. Using a linear model relating those DI values to corrosion pit radius, it is demonstrated that corrosion pit from 30 µm to 150 µm can be reliably detected, located, and their upcoming size extrapolated. Two independent experiments were achieved in order to ensure the repeatability of the proposed approach. LW managed by a sparse PZT array thus appears to be reliable and efficient to monitor growth of µm-sized corrosion pits on 316L steel plates. If embedded in aeronautical structure, such an approach could be a versatile and cost-effective alternative to actual non-destructive maintenance procedures that are time and manpower consuming.

Rice blast incidence and determination of morphological variation of Magnaporthe oryzae, Cav. in Ebonyi State, Nigeria

Blast disease is one of the major threats to rice production globally. This study investigates the prevalence, incidence, severity, damage index and morphological variation of blast disease in lowland rice in nine local government areas of Ebonyi State, Nigeria. Ebonyi State lies within Latitudes 6°15′57″N and 6°24′70″N, Longitudes 7°42′18″E and 8°26′20″E in the derived savannah zone of Nigeria. A survey was conducted on twenty-six (26) rice farms between October and November, 2017 when the rice had reached physiological maturity and infection of rice plants with blast was evident. Data collected from the farms included; rice variety cultivated, source of the seeds, area of land under cultivation, disease incidence, severity and damage, and control measures. Data obtained on disease incidence, severity and damage index were subjected to Analysis of Variance while significant means were separated with Tukey HSD test at p<0.05. Results on rice blast disease revealed that incidence, severity and damage index varied between fields and location due to the environmental conditions prevalent in each location. The highest mean disease incidence, severity and damage index 53.67%, 2.50 and 38.02% respectively due to blast, were recorded in Ishielu, while Ezza South had the least blast incidence (18.24%), Abakaliki had the least severity (1.30) and Ezza South the least damage index (6.59%). Twenty-two fungal isolates were identified and characterized from infected rice plants obtained from the field. The twenty-two isolates, identified as Magnaporthe oryzae (Mo), grown on potato dextrose agar showed various differences in their cultural and morphological characters such as colony colour, margin, pigmentation, surface texture, shapes, septate and cells. Pathogenicity study revealed the five isolates Mo-03, Mo-05, Mo-06, Mo-10 and Mo-17 where more virulent than others. Therefore, the present study recommends that the government should set up modalities to educate and train rice farmers on disease symptom recognition and the available eco-friendly management methods to reduce epidemic on rice and increase rice production both in the rice producing areas in Nigeria.

Acute toxicity and biodistribution assessment of quantum dots conjugated to lectins from Schinus terebinthifolia leaves (SteLL) and Punica granatum sarcotesta (PgTeL)

This work reports the in vivo investigation of telluride cadmium quantum dots (CdTe QDs) conjugated to plant lectins from Schinus terebinthifolia (SteLL) and Punica granatum (PgTeL) for acute toxicity and genotoxicity in healthy mice and 24-h biodistribution in sarcoma 180-bearing animals. Acute toxicity data indicated their safety, despite some histopathological alterations. Comet assay revealed that the QDs-PgTeL group presented a higher damage index and frequency of damage than the negative control. The micronucleus test did not reveal a genotoxic effect. The 24-h biodistribution study showed a major uptake of cadmium by the liver, spleen, and kidneys. A greater accumulation of cadmium was found in tumors of the QDs-SteLL group. In conclusion, the biodistribution study showed no influence of the studied lectins in the absorption of QDs by different organs and that the conjugation of SteLL resulted in increased targeting of QDs to sarcoma 180 cells, suggesting a potential theranostic application in cancer.

A Preparation and Characterization of Chitosan-Silica Membranes and Applications for Creatinine and Urea Transport

The main organ that of the urinary system after the main organ functions to filter waste products from the body's metabolism that must be removed through the excretion process is the kidneys. The remaining metabolite compounds that accumulate in the blood are caused by the kidneys being unable to filter and remove uremia toxin compounds such as urea and creatinine from the body. One indication of kidney damage can be seen from levels of creatinine and urea in the blood that exceed normal limits. Urea and creatinine levels can be lowered by improving kidney function, namely by the blood washing process (hemodialysis). In the hemodialysis technique, the price of an artificial kidney or hemodialyzer is very expensive so that kidney failure sufferers require very large costs for treatment. To overcome this problem, alternative natural materials are needed to make membrane artificial kidneys. The aim of the research is (1) to analyze the synthesis and characteristics of membranes and, (2) to apply them for the transport of creatinine and urea using silica chitosan membranes. Characterization includes functional group testing using an Fourier-Transform Infrared (FTIR) spectrophotometer, water absorption test (swelling test), tensile test, and morphology with Scanning Electron Microscope (SEM). The membranes were applied for creatinine transport with varying concentrations of 70, 100, and 130 mg/L. It was also used for transporting urea at various concentrations of 500, 1000, and 1500 mg/L. This study disclosed a window of opportunity to produce novel hemodialysis membranes using bio-based materials. Keywords: Biocompatibility, chitosan, creatinine, hemodialysis, membrane, silica, urea

Evaluation of the performance and effect of steel fiber reinforced cellular concrete for underwater blast protection under contact explosion loading

The reinforced concrete structure is more likely to be destroyed under the action of underwater explosion load, which makes the overall structure have the risk of instability. The purpose of this paper is to study the underwater anti-explosion protection performance of steel fiber reinforced cellular concrete protective layer. The FEM-SPH coupling method was used to study the underwater damage process, dynamic response, failure mode and protection effect of the protected structure strengthened by eight different proportions of protective layers. The results show that the addition of steel fiber reinforced cellular concrete protective layer can effectively improve the anti-explosion performance of the protected structure, and its anti-explosion performance is directly related to the volume fraction of steel fiber in the protective layer. Under different ratio protection schemes, the total energy absorption and protection rate of the protective layer increase first and then decrease with the increase of the volume fraction of steel fiber in the protective layer, while the peak pressure of the protected structure at the measuring point and the failure volume rate of the whole structure decrease first and then increase. Among them, the underwater wave attenuation and energy consumption effect of SAP10S15 protective layer is the most prominent, and its total energy absorption is 20 % higher than that of other protective layers. Under this ratio protection scheme, the shock wave pressure of the protected structure is greatly attenuated, and the peak pressure of each measuring point is reduced by about 35.8 %, 37.9 %, 23.7 %, 27.9 % and 35.1 % respectively compared with the unprotected scheme. The damage degree of the protected structure under the SAP10S15 ratio protection scheme is significantly reduced. The failure volume rate and damage index are 8.03 % and 0.21, respectively, which are 37.7 % and 42.5 % lower than those of the unprotected scheme. The damage level is reduced from serious damage to moderate damage. In addition, the damage grade prediction curve of the protected structure is constructed, and the predicted value of the curve is in good agreement with the simulation results, which can provide a reference for the rapid evaluation of the underwater explosion-proof performance of the steel fiber reinforced cellular concrete protective layer.

Study of bond-slip performance of steel tube with UHPC based on acoustic emission parameter analysis

Conventional methods for assessing bond performance are hindered by challenges in measuring strain and a lack of sufficient sensitivity to internal structural damage. This paper examines the bond behavior between steel and ultra-high-performance concrete (UHPC) based on acoustic emission (AE). The tests included a total of 2 concrete-filled steel tube (CFST) specimens and 4 concrete-encased CFST specimens. The bonding test was analyzed using AE parameters in combination with the damage process, damage morphology, and loading curve of the test specimens. Furthermore, damage correspondence was explored for the AE parameter indexes and the bond damage indexes of the conventional method. The findings reveal that the AE peak frequencies associated with the bond failure between steel tube and concrete span 30–100 kHz, 110–130 kHz, and 220–260 kHz. The AE event rate, cumulative absolute energy, Ib-curve, and percentage of tensile cracks can be used as judgmental and early warning features for interface damage. The damage process at the interface and the concrete crack development can be characterized by the severity index HI and the severity value Sr. The measurement curves obtained from various AE sensor positions exhibit remarkable similarity. A correlation can be discerned between the severity index (Sr) of the AE and the bond damage degree (Dt) ascertained through conventional methods, effectively mirroring the structural damage progression.

Probabilistic modelling of steel column response to far-field detonations

Due to the deficiency of current design guidelines for blast loadings on steel structures, this research develops probabilistic models for steel wide-flange columns under axial and far-field blast loading on both their weak and strong axes. A total of 160 finite element (FE) simulations were conducted using ANSYS LS-DYNA, with columns subjected to different Axial Load Ratios (ALRs) and blast impulses. Validation against two experimental tests showed a strong correlation in displacement plots, with a material model accounting for strain rate effects. Probabilistic models for predicting maximum displacement and residual axial capacity were formulated using Bayesian inference and posterior statistics. These models were developed by incorporating dimensionless physics-based explanatory functions. The slenderness ratio of the column was identified as the most influential. The models account for uncertainties such as material and geometric properties, as well as strain rate effects. Graphical plots between the ALR and Damage Index (DI) were examined to assess the column's damage level. Furthermore, the probability of failure (fragility) of four columns for similar blast impulse was assessed w.r.t DI. These models along with ALR vs DI plots will be useful tools to know the level of building occupancy and retrofitting options.

Research on damage identification of simply supported bridge based on effect size method for vehicle-bridge coupled vibration

Abstract This paper presents a novel bridge damage identification method employing Cohen’s d as an effect size indicator, predicated on the detection of bridge damage through the coupled vibration between a vehicle and the bridge. By analysing the dynamic response of the bridge as a vehicle passes over, this method effectively extracts the modal parameters of the bridge and facilitates the identification of bridge damage. Numerical models of the bridge under various damage conditions, including no damage, mid-span damage, and damage at the 1/4 and 3/4 span locations, have been constructed to substantiate the efficacy and precision of the effect size as a damage indicator. Furthermore, to address the challenge of accurately identifying damage at boundaries, which is often confounded by boundary effects, a boundary subdivision method has been defined for the detection of boundary damage. Through the implementation of a real-bridge test based on indirect measurement technology, the self-vibration frequency of the bridge was successfully extracted. This empirical data was then compared and analysed against results from ANSYS numerical simulations, thereby validating the practicality and accuracy of the proposed method. In the final analysis, the influence of random traffic flow on the bridge damage identification results was examined. The findings indicate that the vibrations in simply supported beam bridges are intensified due to the impact of random traffic flow, which aids in enhancing the accuracy of damage identification. The introduction of this method provides a new quantitative tool for bridge health monitoring, enabling the rapid and accurate identification of bridge damage without interrupting traffic. It holds significant value for engineering applications in bridge maintenance and safety assessment.

Advanced Parameters of Myocardial Strain and Cardiac Biomarkers Indicate Subclinical Systolic Myocardial Dysfunction in Patients with Systemic Lupus Erythematous.

Background: Systemic lupus erythematosus (SLE) is characterized by inflammation and cardiovascular complications. Our study aimed to investigate subclinical and early indicators of systolic myocardial dysfunction in SLE patients using advanced echocardiographic methods and biomarkers. Methods: In this cross-sectional study, we enrolled 102 SLE patients without known cardiac impairment and 51 healthy controls. Demographics, disease characteristics, laboratory results, disease activity (SLEDAI), and organ damage (SDI) indices were recorded. Left ventricular global longitudinal strain (GLS) and myocardial work indices were assessed by utilizing speckle tracking echocardiography. In addition, high-sensitivity C-reactive protein (hsCRP), high-sensitivity troponin (hsTn), and N-terminal-pro B-type natriuretic peptide (NT-proBNP) levels were measured in blood samples. Results: In comparison with controls, SLE patients had significantly higher GLS (-19.94 ± 2.71% vs. -21.15 ± 1.55%, p < 0.001) and global wasted work (GWW) (94 ± 71 mmHg% vs. 71 ± 49 mmHg%, p = 0.025). Notably, NT-proBNP and hsTn were threefold and twofold higher in the SLE group compared with the control group, respectively (p < 0.001). Within the SLE cohort, in patients with at least moderate disease activity (SLEDAI ≥ 4), both biomarkers were significantly more elevated than those with low disease activity (SLEDAI < 4). Notably, hsTn levels remained within the normal range. Conclusions: Advanced echocardiographic parameters combined with specific biomarkers have a promising role in detecting systolic dysfunction in SLE patients, potentially enabling timely interventions to mitigate cardiovascular risk.