Damage Events Research Articles

Estimating the impact of indirect action in neutron-induced DNA damage clusters and neutron RBE

Background: Neutron radiation protection factors indicate that the risk of neutron-induced stochastic biological effects is higher compared with other types of ionising radiation, and has strong energy dependence. Recent Monte Carlo studies simulated neutron radiation on a nuclear DNA model and demonstrated that the energy-dependent radiobiological risk of neutrons can be correlated with the induction of DNA damage clusters, particularly those that contain difficult-to-repair double-strand breaks. The main limitation of these studies is that only direct radiation action was investigated. Thus, for a more comprehensive understanding of pre-repair neutron-induced DNA damage, indirect action must be modelled and its impact must be quantified. Methods: An open-source algorithm for indirect action available in the TOPAS-nBio track structure Monte Carlo toolkit was adapted into our group’s existing TOPAS and TOPAS-nBio simulation pipeline for neutron and photon radiation. We performed 100 independent simulated irradiations of monoenergetic neutrons from 1 eV to 10 MeV on our existing custom-built nuclear DNA model, and scored various types of DNA damage due to direct and indirect action. The yields of DNA damage were stratified according to the damage-inducing action. For the resulting clusters of DNA damage, we determined the average cluster length and lesion count per cluster. This procedure was also performed for 250-keV x-ray photons that served as our reference radiation. We estimated neutron relative biological effectiveness (RBE) by dividing the neutron-inflicted yield of DNA damage clusters by photon-inflicted counterparts. Finally, we compared our RBE results with established radiation protection factors and previous studies that modelled direct action alone. Results: The inclusion of indirect action increased the yield of DNA damage significantly (the increase varies with damage type). We found that the majority of neutron-induced DNA damage events were isolated simple lesions due to indirect action, while most clustered lesions were hybrid in nature (i.e. contain lesions due to direct and indirect action). As for cluster properties, the inclusion of indirect action increased the average length of clusters by approximately 50% and the number of lesions per cluster by approximately 25%. Our estimated energy-dependent neutron RBE for inducing DNA damage clusters follows similar trends as the established radiation protection factors and the previous direct-action-only estimates, but is lower in magnitude. We found that this lower magnitude is due to the greater impact of indirect action in the yield of photon-induced clustered DNA damage compared with neutron-induced clustered lesions. Conclusion: Indirect action has significant effects on radiation-induced DNA damage clusters in terms of yield, length, and lesion count per cluster, and serves to amplify the effects of direct action. The energy-dependent risk of neutron-induced stochastic effects is likely related to, but not completely explained by, the induction of DNA damage clusters. For a more complete model of neutron RBE, the investigation of factors such as DNA damage repair and non-targeted radiation effects is recommended.

Time-Dependent Damage Evolution of Reinforced Concrete Bridge Piers: Implications for Multihazard Analysis

Explicit multihazard analysis of structures, especially bridges, has attracted significant attention from researchers and practitioners. Depending on the number of hazards considered and the length of the time interval, such analysis can be time-consuming and cumbersome for practical purposes. Therefore it would be beneficial to determine under what conditions such analysis is necessary. This paper explored the damage scenarios and performance criteria under which typical overpass bridges in the US require an explicit multihazard analysis. The paper concentrated on three common hazards (in addition to gravity loads): seismic, scour, and corrosion. Throughout the analysis, seismic hazard was assumed to be dominant. To explore this question, the paper used a probabilistic methodology to model time-dependent damage processes in RC. The dominant uncertainties in the modeling process are those associated with earthquake occurrence and intensity, corrosion initiation time and rate, and stream flow intensity. To quantify structural damage, a Park–Ang damage index is used. The damage index evolves with the age of the simulated structure and the combined effect of multiple hazards. It was found after examining several realistic bridge designs that the combined effect of multiple hazards throughout the life of the structure becomes important when evaluating low-probability damage events (such as collapse).

The Damage Assessment for Rapid Response (DARR) Method and its Application to Different Ground-Motion Levels and Building Types

AbstractSeismic recordings in buildings and on the ground are increasingly available due to the increment and expansion of seismic monitoring networks worldwide. However, most urban strong-motion networks consist of stations installed at the ground or, less frequently, in selected building’s basement. It is, therefore, of utmost importance to develop methods that can provide estimates of expected structural damage, starting from earthquake recordings at the ground level. Damage Assessment for Rapid Response (DARR) provides first-level estimates of the expected damage to buildings, based on ground-motion recordings and simple information on buildings’ characteristics. In this work, we apply DARR using both weak and strong ground-motion recordings available for different low- and mid-rise building typologies. A total of 9 buildings and 19 earthquake recordings were analyzed. DARR reproduces the shaking at the building’s top, and estimates the peak structural relative displacement or average interstory drift. Results show that the method works well for the considered building types and ground-motion levels for the estimation of relative and total displacements using first-order assessments. Comparison with the previously defined thresholds allows the estimation of expected damage. Our results (i.e., no damage for most buildings and events) are consistent with the absence of damaging events in northeastern Italy in the studied period (2019–2021). For a school building in central Italy, which was heavily damaged by the 2016 Central Italian sequence, DARR correctly predicted this fact.

The Damage Mode Automatic Identification of Al2TiO5 Flexible Ceramics Based on Machine Learning

Machine learning is applied to study the damage evolution of Al2TiO5 (AT) flexible ceramics at different sintering temperatures to realize the automatic identification of damage modes. Three damage modes (i.e., friction of Al2TiO5 grains, damage of grain boundary glass phase, and fracture of single Al2TiO5 grain) can be successfully distinguished by processing feature values of acoustic emission (AE) collected from material damage through k‐means algorithm. Though the specimen sintered at 1600 °C possesses the largest grain, the mean feature value of AE in cluster‐3 (fracture of AT single grain) is not maximum since the decomposition of Al2TiO5 is serious at 1600 °C. Meanwhile, the amplitude‐centralized area of the corresponding cluster first expands and then decreases with the increase of sintering temperature. When the sintering temperature is 1500 °C, this centralized area reaches to the maximum. Correspondingly, the specimen sintered at 1500 °C has the maximum failure displacement and the most AE damage events. To realize the automatic identification of damage modes, random forests algorithm is applied to distinguish the damage modes of other samples in the same set. The almost same trend of damage modes evolution in new samples and training sample proves high efficiency of this method.

Clamp Loader Processing Is Important during DNA Replication Stress.

The DNA clamp loader is critical to the processivity of the DNA polymerase and coordinating synthesis on the leading and lagging strands. In bacteria, the major subunit of the clamp loader, DnaX, has two forms: the essential full-length τ form and shorter γ form. These are conserved across bacterial species, and three distinct mechanisms have been found to create them: ribosomal frameshift, transcriptional slippage, and, in Caulobacter crescentus, partial proteolysis. This conservation suggests that DnaX processing is evolutionarily important, but its role remains unknown. Here we find a bias against switching from expression of a wild-type dnaX to a nonprocessable τ-only allele in Caulobacter. Despite this bias, cells are able to adapt to the τ-only allele with little effect on growth or morphology and only minor defects during DNA damage. Motivated by transposon sequencing, we find that loss of the gene sidA in the τ-only strain slows growth and increases filamentation. Even in the absence of exogenous DNA damage treatment, the ΔsidA τ-only double mutant shows induction of and dependence on recA, likely due to a defect in resolution of DNA damage or replication fork stalling. We find that some of the phenotypes of the ΔsidA τ-only mutant can be complemented by expression of γ but that an overabundance of τ-only dnaX is also detrimental. The data presented here suggest that DnaX processing is important during resolution of DNA damage events during DNA replication stress. Although the presence of DnaX τ and γ forms is conserved across bacteria, different species have developed different mechanisms to make these forms. This conservation and independent evolution of mechanisms suggest that having two forms of DnaX is important. Despite having been discovered more than 30 years ago, the purpose of expressing both τ and γ is still unclear. Here, we present evidence that expressing two forms of DnaX and controlling the abundance and/or ratio of the forms are important during the resolution of DNA replication stress. IMPORTANCE Though the presence of DnaX τ and γ forms is conserved across bacteria, different species have developed different mechanisms to make these forms. This conservation and independent evolution of mechanisms suggest that having two forms of DnaX is important. Despite having been discovered more than 30 years ago, the purpose of expressing both τ and γ is still unclear. Here, we present evidence that expressing two forms of DnaX and controlling the abundance and/or ratio of the forms is important during the resolution of DNA replication stress.

Structural Health Monitoring via Phase Space Warping and Time-Delay Embedding

The state of a structure’s health can be determined by investigating its vibration characteristics. Vibration-based structural health monitoring (SHM) enables early detection and diagnosis of damage as well as extension of service life. Herein, linear and nonlinear tracking metrics are proposed to track deterioration in the condition of multistory structures and assess their instantaneous health in real-time via measurement of floor accelerations. The linear metrics, the amplitude damage index ADIn(t¯) and the frequency damage index FDIn(t¯), are based on tracking the power spectra of floor accelerations. The nonlinear metric e(t¯) is based on a novel implementation of the phase-space warping method and obtained from the orbits representing the floors’ motions in pseudo phase-space. A scaled-down model of a four-floor moment-resisting frame building is designed and fabricated to demonstrate and to compare the capabilities of the three damage indices. Structural damage is introduced to individual columns, to mimic damage initiation, by cutting two notches on opposite sides of a column cross-section at midheight. The ADIn(t¯) detected large damage events, fast deterioration beyond them, and the onset of failure using any of the four floor accelerations. The FDIn(t¯) proved insensitive to damage compared with the other two metrics. The nonlinear metric e(t¯) detected gradual (fatigue-induced) deterioration in the building’s health before introduction of damage, large damage events, fast deterioration beyond them, and the onset of failure, using any of the four floor accelerations. The e(t¯) metric varied slowly and continuously with gradual deterioration and exhibited larger discontinuous jumps with discrete damage events. This was true for all three damage experiments undertaken on the model building. The nonlinear e(t¯) metric was also found to be more efficient, in terms of signal utilization, in comparison with the linear ADIn(t¯) metric.

Overview of Cochrane Systematic Reviews of rehabilitation interventions for persons with rheumatoid arthritis: a mapping synthesis.

The aim of this paper was to provide an overview of Cochrane Systematic Reviews (CSRs), which synthesizes the quality and quantity of available evidence on the effectiveness of rehabilitation interventions in rheumatoid arthritis (RA). The World Health Organization (WHO) requested Cochrane Rehabilitation the CSRs search to develop the Package of Interventions in Rehabilitation (PIR). We searched the Cochrane Library using the terms "rheumatoid arthritis" and "rehabilitation." We screened the CSRs according to the search strategy based on the methodology developed for the WHO PIR. The search period for the data provided to WHO was between 1 September 2009 and 2019. We updated the search to 1 September 2022 for this paper. We summarized the CSRs identified after the screening process using an evidence map, grouping outcomes, and comparisons of included CSRs indicating the effect and the quality of evidence to provide a comprehensive view of current knowledge. We identified 10 CSRs, including 92 primary studies with 10,801 participants and 23 comparisons. They explored the effectiveness and/or safety of either non-pharmacological or pharmacological (for symptom control only) interventions. Outcomes were pain, muscle strength, grip/pinch strength, tender joints, swollen joints, fatigue, disease activity, radiological damage, physical function, hand function, participant adherence, clinical improvement, withdrawals, and adverse events. Our mapping synthesis indicates that physical activity and exercises in RA are effective non-pharmacological interventions for some outcomes, such as hand function, muscle strength and fatigue, without any deterioration of pain, disease activity and radiological involvement. Psychosocial interventions show a small beneficial effect on fatigue. Regarding pharmacological agents, celecoxib presents similar analgesic effects with traditional NSAIDs but fewer gastric adverse events. Current evidence supports physical activity and exercise programs for individuals with RA. However, well-designed studies will help document the exact effects of these programs on different outcomes and physiological mechanisms in RA. There were inconclusive results for some of the interventions due to low and very-low quality of evidence. Furthermore, due to the lack of CSRs on therapeutic patient education, orthoses, physical modalities and assistive devices in the search period, it was impossible to synthesise the evidence on those interventions.

Slab damage and the pulsating retreat of the Ionian-Apennines subduction

AbstractEpisodes of slow and fast plate subduction, slab rollback, and backarc opening are widely documented; e.g., in the central Mediterranean region. Pervasive damage by fluids is emerging as a possible weakening mechanism that could lead to slab segmentation and breakoff. We show that low-velocity anomalies within the Ionian slab present in along-dip seismic tomography profiles are traces of past damaging events generated by water penetration into the oceanic lithosphere when it was at the trench. We propose that the stepwise evolution of the central Mediterranean over the past 21 m.y. has been governed by strength changes of the Ionian slab induced by damage. More generally, we speculate that the cyclicity of such a process in space and time in the different circum-Mediterranean subduction events may have led to the present shape of the Mediterranean basin.

MINAS TIRITH: a new tool for simulating radiation-induced DNA damage at the cell population level

Objective. The mechanisms of radiation-induced DNA damage can be understood via the fundamental acquisition of knowledge through a combination of experiments and modeling. Currently, most biological experiments are performed by irradiating an entire cell population, whereas modeling of radiation-induced effects is usually performed via Monte Carlo simulations with track structure codes coupled to realistic DNA geometries of a single-cell nucleus. However, the difference in scale between the two methods hinders a direct comparison because the dose distribution in the cell population is not necessarily uniform owing to the stochastic nature of the energy deposition. Thus, this study proposed the MINAS TIRITH tool to model the distribution of radiation-induced DNA damage in a cell population. Approach. The proposed method is based on precomputed databases of microdosimetric parameters and DNA damage distributions generated using the Geant4-DNA Monte Carlo Toolkit. First, a specific energy was assigned to each cell of an irradiated population for a particular absorbed dose following microdosimetric formalism. Then, each cell was assigned a realistic number of DNA damage events according to the specific energy respecting the stochastic character of its occurrence. Main results. This study validated the MINAS TIRITH tool by comparing its results with those obtained using the Geant4-DNA track structure code and a Geant4-DNA based simulation chain for DNA damage calculation. The different elements of comparison indicated consistency between MINAS TIRITH and the Monte Carlo simulation in case of the dose distribution in the population and the calculation of the amount of DNA damage. Significance. MINAS TIRITH is a new approach for the calculation of radiation-induced DNA damage at the cell population level that facilitates reasonable simulation times compared to those obtained with track structure codes. Moreover, this tool enables a more direct comparison between modeling and biological experimentation.

Effects of short-term high-concentration exposure to PM2.5 on pulmonary tissue damage and repair ability as well as innate immune events

Short-term heavy air pollution still occurs frequently worldwide, especially during the winter heating period in some developing countries, which is usually accompanied by the temporary explosive growth of PM2.5. The pulmonary damage caused by PM2.5 exposure has been determined, but there have been few studies on the repair ability after the cessation of exposure and the important role of innate immune events. This study established a short-term (30 days) high-concentration (15 mg/kg body weight) PM2.5 exposure and recovery (15 days of exposure cessation) model by intratracheal instillation. The results showed that short-term PM2.5 exposure increased the content of collagen fiber in rat lung tissue, which was significantly repaired after recovery by 15 days of exposure cessation. Meanwhile, exposure to PM2.5 also caused changes in lung epithelial function, macrophage polarization and cell autophagy function. Most of these changes could be restored or reversed to a certain extent after recovery. However, there were also some biomarkers, including CLDN18.1, SP-A, SP-D, iNOS, CD206, Beclin1, p62 and LC3B, that were still significantly different between the exposure and control groups after recovery, suggesting that some toxic effects, especially epithelial function damage, were not completely repaired. In addition, there was a significant correlation between pulmonary fibrosis and innate immunity. The present study demonstrated that short-term high-concentration exposure to PM2.5 could cause temporary lung tissue damage and related innate immune events in rats, and the repair ability existed after the cessation of exposure, but part of the damage that required special attention still persisted.

Mycobacterium tuberculosis Cell Wall Antigens Induce the Formation of Immune Complexes and the Development of Vasculitis in an Experimental Murine Model.

Tuberculosis (TB) of the central nervous system (CNS) presents high mortality due to brain damage and inflammation events. The formation and deposition of immune complexes (ICs) in the brain microvasculature during Mycobacterium tuberculosis (Mtb) infection are crucial for its pathobiology. The relevance of ICs to Mtb antigens in the pathogenesis of CNS-TB has been poorly explored. Here, we aimed to establish a murine experimental model of ICs-mediated brain vasculitis induced by cell wall antigens of Mtb. We administered a cell wall extract of the prototype pathogenic Mtb strain H37Rv to male BALB/c mice by subcutaneous and intravenous routes. Serum concentration and deposition of ICs onto blood vessels were determined by polyethylene glycol precipitation, ELISA, and immunofluorescence. Histopathological changes in the brain, lung, spleen, liver, and kidney were evaluated by hematoxylin and eosin staining. Our results evidenced that vasculitis developed in the studied tissues. High serum levels of ICs and vascular deposition were evident in the brain, lung, and kidneys early after the last cell wall antigen administration. Cell wall Mtb antigens induce strong type III hypersensitivity reactions and the development of systemic vasculitis with brain vascular changes and meningitis, supporting a role for ICs in the pathogenesis of TB.

Модели и алгоритмы создания комплексных аварийно-спасательных формирований на объектах горнорудной промышленности

Introduction. The article discusses scientific approaches and regulatory requirements for the creation and functioning of emergency services at mining facilities. Special emergency rescue services at mining facilities respond to a variety of accidents and incidents by nature, the types and frequency of which depend on the danger of the enterprise, which requires the creation of several specialized emergency rescue services independent of each other. The costs of maintaining emergency rescue units are borne by enterprises, and in the conditions of a significantly large staff of such services, they can become unacceptably high. In this regard, there is an economic justification for combining the personnel of operational duty shifts of several specializations of activities aimed at optimizing the staffing of services and formations. The purpose of the study is to increase the level of safety of mining facilities based on the development of models and algorithms for the creation of complex emergency rescue units capable of responding to all types of possible accidents and incidents. Research methods. The article uses the method of analytical research based on the results of the analysis of work in the field of organizational design of regular structures of emergency services. The results of the study. Approaches to the creation of emergency rescue services at industrial facilities are defined. The models of creation of complex emergency rescue formations and the algorithm of creation of emergency rescue formations at mining facilities are proposed. Conclusion. The current norms for determining the organizational structures of mountain rescue teams do not take into account the types of accidents, the specifics of their development and the response of emergency rescue units to their elimination. The authors have proposed models of complex emergency rescue units at mining facilities, allowing, depending on the chosen option, to respond to all possible accidents and incidents. The proposed models and algorithm allow emergency rescue units at mining facilities to optimize the organizational and staff structure by combining rescuers of various specializations of activity, which in turn can reduce the costs of the enterprise for the maintenance of emergency services. Keywords: accident; emergency rescue formation; mining rescue squad; mining industry; damaging events; incident; hazardous production facility; organizational design; organizational and staff structure.

S-35-4: PEAK OF NOCTURNAL BLOOD PRESSURE SURGE IN SECONDS IS ASSOCIATED WITH LEFT VENTRICULAR MASS INDEX IN OBSTRUCTIVE SLEEP APNEA PATIENTS

Background: Nocturnal blood pressure (BP) surge in seconds (sec-surge), which is characterized as acute transient BP elevation over several tens of seconds, could be a predictor of target organ damage and trigger cardiovascular events. Sec-surges are induced by sleep apnea (SA) or sympathetic nerve activity. However, it is not clear that the severity of sec-surge is different between sec-surges induced by SA (apnea/hypopnea detected by polysomnography (PSG) or oxygen desaturation) and those induced by non-SA factors (rapid eye movement, micro arousal, etc.). Furthermore, it is also not clear whether the sec-surge increases the cardiac overload. Methods and Results: Firstly, we assessed the sec-surge severity between sec-surges induced by SA and those induced by non-SA factors by comparing the sec-surge variables. Secondly, we assessed the association between sec-surges and left ventricular hypertrophy (LVH) independently of conventional BP variables. We assessed these points with 41 patients (mean age 63.2 ± 12.6 years, 29% female) who underwent full PSG, beat-by-beat (BbB) BP, and cuff-oscillometric BP measurement during the night. All patients were included for the analysis comparing sec-surge severity between inducing factors (SA and non-SA factors). There were no significant differences in the number of sec-surges/night, the peak of sec-surges defined as the maximum systolic BP in each sec-surge, and the amplitude of sec-surges defined as peak of sec-surge minus start point systolic BP in each sec-surge between SA-related sec-surges and non-SA-related sec-surges (19.5 ± 26.0 vs. 16.4 ± 29.8 events/night; 148.2 ± 18.5 vs. 149.3 ± 19.2 mm Hg; and 26.0 ± 4.3 vs. 25.8 ± 5.7 mm Hg, respectively). Eighteen subjects who had inspection results of cardiac magnetic resonance imaging out of the 41 patients (mean age 65.0 ± 12.5 years, 33% female) were included for the analysis assessing the association between sec-surges and LVH. The peak of sec-surge was significantly and strongly correlated with left ventricular mass index (LVMI) (r = 0.607, p < .01). As a result of multiple regression analysis (n = 18), the peak of sec-surge was significantly and strongly associated with the LVMI (standardized β = 0.62, p = .02), compared with the mean nocturnal SBPs measured by oscillometric method (standardized β = -0.04, p = .87). Conclusions: This study suggests that peak of sec-surge could be a better predictor of LVH compared to parameters derived from regular nocturnal oscillometric SBP.

Anakinra for patients with COVID-19: an updated systematic review and meta-analysis

Severe COVID-19 patients can develop a maladaptive immune response with hyper-production of cytokines and chemokines which lead to alveolar damage, endothelial activation, coagulopathy and thromboembolic events. We performed a meta-analysis which included any study performed on COVID-19 patients with respiratory hypoxemic failure who received anakinra versus any comparator. Primary endpoint was mortality. Secondary endpoints were intubation rate, superinfection and thromboembolic events. Subgroups analyses included patients in general ward, with hyperinflammation and/or baseline ratio of arterial oxygen partial pressure (PaO2) to fractional inspired oxygen (FiO2) >200. Twenty-four studies were included. Mortality in anakinra patients was significantly lower than mortality of controls (19% vs. 28%; p < 0.0001). Anakinra patients had significantly lower risk of intubation (16% vs. 33%; p < 0.001). Mortality reduction was confirmed in general ward settings, in patients with hyperinflammation and with PaO2/FiO2 >200, but not when selecting randomized studies only. A trend towards increased mortality in more severe patients was observed.

Ambulatory Blood Pressure Monitoring Section in Normotensive Type 2 Diabetes Mellitus: An Observational Study

Introduction: Hypertension (HTN) is a major cause of cardiovascular morbidity and mortality, particularly in diabetic people. Because HTN and Type 2 Diabetes Mellitus (T2DM) frequently co-exist, HTN is a significant risk factor for chronic problems masked HTN affects around a one third of T2DM patients who have normal Blood Pressure (BP) readings in the clinic. T2DM patients frequently have normal office BP (BP) and no nocturnal BP falling. The non dipping BP pattern raises the risk of cardiovascular events and damage to target organs. Multiple BP recordings can be obtained with Ambulatory BP Monitoring (ABPM). By providing variability of BP, and diurnal variation in BP, it assists the treating physician in the diagnosis and management of HTN. Aim: To elucidate the prevalence of non dipping pattern in T2DM and the characteristics of diabetics who have non dipping pattern using ambulatory monitoring. Materials and Methods: This was an observational study carried out in the Department of Medicine at JIPMER, Pondicherry, India. Between January 2016 and December 2017, 110 patients with T2DM were visited to Medicine Outpatient Department and the Diabetic Clinic. Out of 110, a total of 62 patients, with an average age of 46.67 years, were included in the study. Sun Tech Oscar 2’ 24 hourR ABPM system was used for the study of ambulatory BP of patients, at specified times. Results: Sixty-two normotensive T2DM patients, mean age of 46.67 years were analysed in the 24 months. A total of 62 patients, the non dipping pattern was seen in 47 (76%) of the 62 individuals evaluated for ABPM, while the dipping pattern was seen in 15 (24%) of the normotensive T2DM patients. A non dipping pattern was associated with a higher Body Mass Index (BMI) (p-value=0.03). A non dipping habit was also substantially associated with high PPBS values (p-value=0.02). Conclusion: Patients with a history of HTN and smoking had a higher chance of non dipping patterns, which may lead to endorgan damage and future cardiovascular events. ABPM can be used as a screening tool to predict cardiovascular events in T2DM.

A Hybrid Model Integrating CNN–BiLSTM and CBAM for Anchor Damage Events Recognition of Submarine Cables

A Hybrid Model Integrating CNN–BiLSTM and CBAM for Anchor Damage Events Recognition of Submarine Cables

A brief overview of the studies on the climatic impact of heavy precipitation events in Hungary

Climate change is one of the major problems of our day. In different areas of the earth, climate change causes different problems. On the European continent, according to observations, the dry and rainy periods have changed significantly. During rainy periods, the amount of water from the rain falling in a short period increased significantly. The authors' research focused on a smaller East-European area, Hungary. A significant part of damage events in Hungarian settlements is related to surface and underground waters and rainfall activity. The road network, the cellars and the gutters of municipalities are often subject to damage due to the inappropriate construction of the drainage system. The article analyzes the local effects of climate change based on the analysis of the weather data of the past years. The change in the number of rainy days and the amount of rain is evidence of a change in the weather. This work is an overview based on previous studies and statistical data showing the climatic impact in Hungary.

A Multi‐Hazard Risk Framework to Stress‐Test Water Supply Systems to Climate‐Related Disruptions

AbstractWater utilities' supply systems are vulnerable to several climate‐related hazards, including droughts, floods and cyclones. Here we propose a generally applicable framework for conducting multi‐hazard risk assessments of water supply systems and use it to quantify the impact of present and future climate extremes on the national water supply network in Jamaica. The proposed framework involves stress‐testing a model of the system with a large set of spatially coherent drought, cyclone and pluvial and fluvial flood events to calculate the number of water users whose supplies would be disrupted during an event, that is, the Customer disruption days (CDD). We estimate the total multi‐hazard annual expected disruption to be approximately 5 days per year per utility customer under present conditions. This is increased by a factor of between 2 and 2.5 when end‐of‐century climate scenarios are propagated through the model. Our analysis shows that more high probability drought events lead to greater CDD compared with asset damage events. However, extreme asset damage events, despite manifesting over shorter timescales (days) compared to drought events (months), can lead to more widespread CDD. This quantified risk framework would allow utility managers to compare the risk of both asset damage‐ and water shortage‐induced disruptions via a common, decision‐relevant metric. However, applications to other utilities would require tailored hazard modeling approaches. The proposed risk assessment is intended to inform prioritization of infrastructure investments, ranging from asset protection to drought mitigation projects, with the goal of enhancing water supply resilience in the face of a changing climate.

Self‐Sensing Cementitious Composites with Hierarchical Carbon Fiber‐Carbon Nanotube Composite Fillers for Crack Development Monitoring of a Maglev Girder

In view of high-performance, multifunctional, and low-carbon development of infrastructures, there is a growing demand for smart engineering materials, making infrastructures intelligent. This paper reports a new-generation self-sensing cementitious composite (SSCC) incorporated with a hierarchically structured carbon fiber (CF)-carbon nanotube (CNT) composite filler (CF-CNT), which is in situ synthesized by directly growing CNT on CF. Various important factors including catalyst, temperature, and gas composition are considered to investigate their kinetic and thermodynamic influence on CF-CNT synthesis. The reciprocal architecture of CF-CNT not only alleviates the CNT aggregation, but also significantly improves the interfacial bonding between CF-CNT and matrix. Due to the synergic and spatially morphological effects of CF-CNT, that is, the formation of widely distributed multiscale reinforcement networks, SSCCs with CF-CNTs exhibit high mechanical properties and electrical conductivity as well as excellent self-sensing performances, particularly enhanced sensing repeatability. Moreover, the SSCCs with CF-CNTs are integrated into a full-scale maglev girder to devise a smart system for crack development monitoring. The system demonstrates high sensitivity and fidelity to capture the initiation of cracks/damage, as well as progressive and sudden damage events until the complete failure of the maglev girder, indicating its considerable potential for structural health monitoring of infrastructures.

238. Acalculous Cholecystitis: A Novel and Lethal Unrecognized Complication in Severe CoVID 19

Abstract Background SARS-COV-2 infection is known to cause tissue damage in several organs outside of the respiratory tract. The pathogenesis of tissue damage is hypothesized to be caused by direct viral damage, endothelial injury, and ischemic or thrombotic events. Gastrointestinal symptoms were first characterized mainly as diarrhea and diffuse abdominal pain and discomfort, which can be hard to interpret in the setting of a generalized inflammatory response; gallbladder injury and inflammation causing acute acalculous cholecystitis has been scarcely reported Methods Here we discuss five cases of patients presenting with symptoms of cholecystitis. All five patients underwent multiple imaging studies, and all of them were compatible with acute cholecystitis; some of them had an imaging report of lithiasic cholecystitis, while the rest were reported with microlithiasis or biliary sludge. Four out of the five patients underwent laparoscopic cholecystectomy; biopsies were taken, consistently those reported with acalculous cholecystitis. The remaining patient died of CoVID 19 complications prior to surgery, but after a percutaneous cholecystostomy tube was placed. Results All these patients have in common the prolonged fasting, because they all required invasive mechanical ventilation, consequently, they all developed multiple focal pneumonia and respiratory distress syndrome. This fast is related to the development of gangrenous ischemia in the gallbladder, which manifests as a late complication due to SARS-CoV-2 infection, in addition to being related to angiotensin-2 converting receptors and virus replication proteins, as well as the pro-inflammatory and hypoxia state that in itself causes the infection (9). All showed a cholestatic pattern, highlighting that this complication developed in an average time of 3 weeks after the onset of SARS-CoV2 symptoms, in addition to the fact that in most cases a negative test was already shown at the time of the complication. Conclusion Acalculous cholecystitis is one of the extrapulmonary complications that has been seen in patients with this infection, not being the most common, but one of those that has generated a higher mortality rate in patients due to its late diagnosis and non-specific clinical picture in certain occasions (9). Disclosures All Authors: No reported disclosures.