Hazard Of Failure Research Articles

The association between endogenous erythropoietin levels and the risk of heart failure in a Chinese community-based population

Abstract Background Patients with heart failure (HF) often have elevated endogenous erythropoietin (EPO) levels, which are associated with disease severity and prognosis. Previous studies have indicated that in the special population elevated endogenous EPO levels are associated with HF and cardiovascular death. However, whether endogenous EPO levels are associated with the risk of HF in the general population remains to be elucidated. Purpose Our study aims to investigate the association between endogenous EPO levels and the risk of HF admission in the general population. Methods We conducted a prospective cohort study on subjects from a Beijing community in China who had no history of stroke or myocardial infarction. Endogenous EPO levels were measured at baseline for all participants. The endpoint of interest was admission with HF. Cox proportional hazard regression models were used to analyze the relationship between endogenous EPO levels and the occurrence of the endpoint. Results A total of 4870 participants were included. Among all participants, the mean (±SD) age was 56.72 ± 8.78 years, with 1802 (37.0%) being men. The median (interquartile range, IQR) EPO level was 13.19 (9.47-18.20) IU/L. During a mean 9.57-year follow-up, a total of 176 (3.6%) subjects experienced heart failure. Subjects were grouped in quintiles according to baseline endogenous EPO levels. Higher and lower endogenous EPO levels were both associated with increased risk of HF (Figure 1A). The Kaplan–Meier curves showed significant differences in cumulative hazards of heart failure among EPO quintiles (log-rank test: P＜0.05) (Figure 1B). After adjusting for covariates, including demographics, traditional risk factors for cardiovascular disease, renal function, and hemoglobin levels, and using the middle quintile (Q3) (11.72-14.94IU/L) of EPO levels as a reference, we found that the highest quintile (Q5) (>19.86 IU/L) was associated with a 159% increased risk of HF admission (HR 2.59, 95% CI 1.57-4.28, P = 0.0002). Similarly, the lowest quintile (Q1) (<8.66 IU/L) was associated with a 94% increased risk (HR 1.94, 95% CI 1.11-3.41, P = 0.0210) (Table 1). Conclusion There exists a "U-shaped" relationship between endogenous EPO levels and HF admission in the general population. Both higher and lower endogenous EPO levels were associated with an increased risk of HF admission in the community population. These findings differ from previous studies, so further research may be needed to explore the underlying pathophysiological mechanisms of endogenous EPO and HF.

Relationship between 3-dimensional aortic geometry and the risk of new-onset heart failure

Abstract Introduction Aortic geometric assessments to date have typically involved cross-sectional imaging of discrete aortic segments. However, the complex 3D geometry of the thoracic aorta, and its relationship to the risk of cardiovascular disease has not been assessed in large studies. Methods We segmented the thoracic aorta in SSFP axial MRI images from 49,282 UK Biobank participants using a deep convolutional neural network (U-Net). We then computed geometric measurements (centerline length, arch height, arch width, arch height-width ratio, arch unfolding index [inverse of tortuosity], curvature and mean, minimum and maximum diameters) in the overall thoracic aorta as well as in 6 subsegments. We quantified their relationship to the risk of cardiomyopathy and heart failure (HF) using multivariable Cox-proportional hazards models. All hazard ratios are standardized. Centerline length was allometrically indexed to body height. Results In models adjusted for age, sex, BMI kg/m2, low-density lipoprotein mg/dl, high-density lipoprotein mg/dl, triglycerides mg/dl, systolic blood pressure and diastolic blood pressure, the curvature of the aorta (HR=0.63; 95% CI=0.39, 0.99; P<0.05), particularly the aortic arch (HR=0.54; 95% CI= 0.35, 0.87; P<0.05) was strongly related to a lower risk of incident cardiomyopathy. A higher arch unfolding index (HR=1.46; 95% CI=1.03, 2.07; P<0.05), higher width-to-height ratio (HR=1.10; 95% CI= 1.02, 1.19; P<0.05) and lower aorta tortuosity (HR=1.20; 95% CI= 1.09, 1.32; P<0.05) were all associated with a higher risk of cardiomyopathy. This aortic geometric pattern was also associated with a greater risk of a new HF diagnosis (arch unfolding [HR=1.23; 95% CI= 1.07, 1.42; P<0.05], width to heigh ratio [HR=1.06; 95% CI= 1.01, 1.11; P0.05]). Conclusion We demonstrate that 3-D thoracic aortic geometric indices are strongly associated with incident cardiomyopathy and HF, independent of classic risk factors. This is likely related to abnormal afterload and ventricular-arterial interactions since adverse geometric remodeling affects left ventricular pulsatile load.Cardiomyopathy & Heart Failure Hazards

Promising Results of Kidney Transplantation From Donors Following Euthanasia During 10-Year Follow-Up: A Nationwide Cohort Study

The outcome of kidneys transplanted following organ donation after euthanasia (ODE) remains unclear. This study analyzed all kidney transplantations in the Netherlands from January 2012 to December 2021, comparing the outcomes following ODE, donation after circulatory death (DCD-III), and donation after brain death (DBD). 9,208 kidney transplantations were performed: 148 ODE, 2118 DCD-III, and 1845 DBD. Initial graft function was compared between these categories. Immediate graft function, delayed graft function and primary non-function in ODE kidney recipients were 76%, 22%, and 2%, respectively, 47%, 50% and 3% in DCD-III kidney recipients and 73%, 25%, and 2% in DBD kidney recipients (overall p-value: p < 0.001). The number of kidneys transplanted over a median follow-up period of 4.0 years (IQR 2.0–6.6), was 1810, including 72 ODE, 958 DCD-III and 780 DBD kidneys. In this period, 213 grafts (11.8%) failed [7 grafts (9.7%) from ODE donors, 93 grafts (9.7%) from DCD-III donors, and 113 grafts (14.5%) from DBD donors]. Kidneys transplanted after euthanasia have a good immediate graft function, a comparable longitudinal 10 years eGFR, and similar graft failure hazard to kidneys from DCD-III and DBD. Kidney transplantation following ODE is a valuable and safe contribution to the donor pool.

Management of the Infected Tissue Expander.

Tissue expander (TE) infection is a critical postoperative complication in two-stage implant-based breast reconstruction (IBBR). We assessed risk factors associated with TE infection and reconstructive loss and examined reconstructive salvage rates. We retrospectively reviewed patients who underwent IBBR with TE placement from 2017 to 2022. Included were patients with TE infection treated with admission and IV antibiotics, interventional radiology (IR) drainage, and/or operative management (washout with or without TE removal and TE replacement, TE removal and replacement with implant, and/or TE removal without replacement). Reconstructive success was defined as maintenance of breast reconstruction for 1 year after TE placement. Of 4,498 patients who underwent IBBR, 305 (338 TEs) met the inclusion criteria. Cox modeling showed higher body mass index, hypertension, radiation, bilateral TEs, acellular dermal matrix use, increasing mastectomy weight, and nipple sparing mastectomy were associated with increased hazard of TE infection. Patients with TE infection had a 54% reconstructive failure rate within 1 year; Cox modeling showed Black race and gram-negative cultures were associated with increased hazard of reconstructive failure within 1 year. Patients who underwent TE replacement with an implant had the most favorable success rate following infection. Overall, 46% of patients admitted with a periprosthetic infection had successful salvage. Patients with TE infection should be started on IV antibiotics with a low threshold for operative intervention based on exam and culture data. While IR can guide operative intervention of periprosthetic infections, our practice has shifted away from IR drainage towards definitive operative management.

Ambient Air Pollution Exposure and Outcomes in Patients Receiving Lung Transplant

Elevated ambient fine particulate matter (PM2.5) air pollution exposure has been associated with poor health outcomes across several domains, but its associated outcomes among lung transplant recipients are poorly understood. To investigate whether greater PM2.5 exposure at the zip code of residence is associated with a higher hazard for mortality and graft failure in patients with lung transplants. This retrospective cohort study used panel data provided by the United Network for Organ Sharing, which includes patients receiving transplants across all active US lung transplant programs. Adult patients who received lung transplants between May 2005 and December 2016 were included, with a last follow-up of September 10, 2020. Data were analyzed from September 2022 to May 2023. Zip code-level annual PM2.5 exposure was constructed using previously published North American estimates. The primary outcome was time to death or lung allograft failure after lung transplant. A gamma shared frailty Cox proportional hazards model was used to produce unadjusted and adjusted hazard ratios (HRs) to estimate the association of zip code PM2.5 exposure at the time of transplant with graft failure or mortality. Among 18 265 lung transplant recipients (mean [SD] age, 55.3 [13.2] years; 7328 female [40.2%]), the resident zip code's annual PM2.5 exposure level was greater than or equal to the Environmental Protection Agency (EPA) standard of 12μg/m3 for 1790 patients (9.8%) and less than the standard for 16 475 patients (90.2%). In unadjusted analysis, median graft survival was 4.87 years (95% CI, 4.57-5.23 years) for recipients living in high PM2.5 areas and 5.84 years (95% CI, 5.71-5.96 years) for recipients in the low PM2.5 group. Having an annual PM2.5 exposure level greater than or equal to the EPA standard 12 μg/m3 was associated with an increase in the hazard of death or graft failure (HR, 1.11; 95% CI, 1.05-1.18; P < .001) in the unadjusted analysis and after adjusting for covariates (HR, 1.08; 95% CI, 1.01-1.15; P = .02). Each 1 μg/m3 increase in exposure was associated with an increase in the hazard of death or graft failure (adjusted HR, 1.01; 95% CI, 1.00-1.02; P = .004) when treating PM2.5 exposure as a continuous variable. In this study, elevated zip code-level ambient PM2.5 exposure was associated with an increased hazard of death or graft failure in lung transplant recipients. Further study is needed to better understand this association, which may help guide risk modification strategies at individual and population levels.

Association of early steroid withdrawal with kidney transplant outcomes in first-transplant and retransplant recipients.

Early steroid withdrawal (ESW) is often preferred over conventional steroid maintenance (CSM) therapy for kidney transplant recipients with low immunological risks because it may minimize immunosuppression-related adverse events while achieving similar transplant outcomes. However, the risk-benefit balance of ESW could be less favorable in retransplant recipients given their unique immunological risk profile. We hypothesized that the association of ESW with transplant outcomes would differ between first-transplant and retransplant recipients. To assess whether the impact of ESW differs between first and retransplant recipients, we studied 210 086 adult deceased-donor kidney transplant recipients using the Scientific Registry of Transplant Recipients. Recipients who discontinued maintenance steroids before discharge from transplant admission were classified with ESW; all others were classified with CSM. We quantified the association of ESW (vs. CSM) with acute rejection, death-censored graft failure, and death, addressing retransplant as an effect modifier, using logistic/Cox regression with inverse probability weights to control for confounders. In our cohort, 26 248 (12%) were retransplant recipients. ESW was used in 30% of first-transplant and 20% of retransplant recipients. Among first-transplant recipients, ESW was associated with no significant difference in acute rejection (aOR=1.04 [95% CI=1.00-1.09]), slightly higher hazard of graft failure (HR=1.09 [95% CI=1.05-1.12]), and slightly lower mortality (HR=0.93 [95% CI=0.91-0.95]) compared to CSM. Nonetheless, among retransplant recipients, ESW was associated with notably higher risk of acute rejection (OR=1.42 [95% CI=1.29-1.57]; interaction p<0.001) and graft failure (HR=1.24 [95% CI=1.14-1.34]; interaction p=0.003), and similar mortality (HR=1.01 [95% CI=0.94-1.08]; interaction p=0.04). In retransplant recipients, the negative impacts of ESW on transplant outcomes appear to be non-negligible. A more conservatively tailored approach to ESW might be necessary for retransplant recipients.

Evaluation of Landslide Hazards Using the Landslide Possibility Index: The Influence of the Exposed Rocks on Landslides in Kirkuk-Koysinjaq Main Road, Northern Iraq

Landslides on slopes occur for various reasons and lead to significant economic losses, adverse influences on the environment, and fatal accidents. The newly constructed road within mountainous areas between the Shewan area and the Taq Taq district linking Kirkuk Governorate to Koysinjaq city experiences annual landslides. This paper aims to use the Landslide Possibility Index (LPI) system to evaluate the stability of slopes, identify the factors that control potential landslides and their severity, as well as the extent and scope of the risks to which slope faces are exposed. Four stations were chosen, data were collected, aerial photographs were studied, and detailed fieldwork was conducted to measure the ten LPI system parameters. The results show that the studied stations varied in failure possibilities, hazard zones, and categories, and that one of the main reasons for the slope failures in the study area is improper road cuttings with a steep angle to the slopes. There is clear control of the exposed rocks on the failures in the studied stations. The severe weathering of the claystone layers within the Bai Hassan Formation triggers secondary types of failures, which are governed by bottom weathering mechanism. Factors like failure to construct sewers or channels to drain rainwater, lack of ditches on the two side of the road, and the absence of fall-preventing techniques and slope stabilization solutions worsen the situation and escalate the hazard of failures.

Multitemporal analysis of cliffs evolution along an Atlantic African coast (Safi Region, Morocco)

Unstable coastal cliffs represent a major threat to coastal infrastructure, housing, and economic activities, which depend on coastal stability. Understanding recession rates and the factors influencing them is therefore essential for enhancing risk prediction and management. Here, we investigated the evolution of coastal cliffs in a crucial sector of the Atlantic African coast in Morocco, stretching from Cap Beddouza in the north to Jorf Lihoudi in the south, covering an area of around 48 km and including the large city of Safi. The instability of these cliffs constitutes the main coastal geological hazard of the area, which has its geomorphological expression in different types of landslides punctuating the coastal cliff. We employed multidecadal aerial imagery along with GIS technique to calculate the rate of change of the cliff over 66 years. Our results indicate that most of the Safi Region coastal zone has undergone recession with rates of change generally variable from 0.04 to 0.08 m/yr ± 0.01 m. The central part of the study area, conversely, experienced the highest retreat rate, exceeding 0.10 m/yr. The spatial variability of recession rates is explained through geological and morphological factors such as the nature of low-strength clay rock formations, favoring large-scale gravity movements. These data are crucial to better define the current level of coastal hazard in this densely populated portion of the Moroccan coast, given that cliff recession have considerable effects on the economic, social and environmental risk of the area. Moreover, this study represents one of the first applications of the Digital Shoreline Analysis System (DSAS) method to an African coastline segment, specifically from Cape Beddouza to the Lihoudi cliffs. More generally, it is among the few studies focused on cliff recession rates in Africa. While a similar application has been conducted for the cliff base in the northern part of the same study area (Raja et al., 2023), that study primarily addresses coastal cliff failure hazards along the Safi coastline in Morocco. In contrast, the present study is focused on determining long-term cliff recession rates and understanding the distribution of these rates and modes of retreat in relation to the physical processes affecting the study area.

Experimental study on energy and damage evolution of dry and water-saturated dolomite from a deep mine

The deformation and failure of a rock is closely related to the strain energy consumption during the load process of rock. To investigate the effect of water on energy evolution and damage characteristics of dolomite samples from a deep mine, the uniaxial compression tests were carried out on dry and water-saturated dolomite samples at different burial depths (900 m–1200 m). The effects of water on the evolution characteristics of elastic and dissipative energy ratios ( Ue/ U and Ud/ U) during rock deformation and failure was analyzed. Based on the variation rate of damage factor ( Df), a new brittleness index is proposed, which can effectively characterize the brittleness characteristics of water-bearing dolomite. The results show that the uniaxial compressive strength and elastic modulus of the water-saturated dolomite are significantly reduced compared to dry sample. The energy and damage evolution process of dolomite can be divided into four stages: initial damage stage, stable damage stage, pre-peak accelerated damage stage and post-damage stage. The variation rate of damage factor of the rock samples in the stable damage stage and the pre-peak accelerated damage stage appeared to increase significantly after water saturation treatment. Compared with water-saturated samples, more pronounced energy hardening characteristics and brittleness characteristics were observed in dry samples. In addition, the possible impact on the stability of deep rock engineering after the deterioration of rock mechanical properties and energy storage properties caused by water was analyzed. Groundwater can somewhat reduce rock burst proneness. However, it also has the potential to lead to greater rock engineering destabilization and failure hazards.

Modified ex-PRESS technique versus Ahmed glaucoma valve as primary glaucoma surgery for hereditary transthyretin amyloidosis glaucoma

Background To compare the efficacy of modified Ex-PRESS technique (ExP) versus Ahmed Glaucoma Valve (AGV) as primary surgery in hereditary transthyretin amyloidosis (ATTRv) secondary glaucoma. Methods Retrospective study at the national amyloidosis centre. Success was defined as an IOP ≥ 6 mmHg and ≤ 21 mmHg with no need for further glaucoma surgery or laser trabeculoplasty and without loss of light perception at the time of the last follow-up. Secondary outcomes included surgical complications, need for hypotensive drugs, and endothelial cell loss. Patients submitted to previous glaucoma surgery were excluded. Results We included 180 eyes of 150 patients, 121 in AGV and 59 in ExP group. No significant baseline differences were found between groups. At the time of last follow-up, both groups exhibited significant intraocular pressure (IOP) reduction (p < .001) and number of glaucoma medications (p < .001). Kaplan-Meyer analysis showed higher cumulative probability of success for AGV group (80.1% vs. 41.1%, p < .001) and higher mean time to failure (54.5 vs. 36.9 months, respectively, p < 0.001) at 60 months follow-up. AGV showed lower hazard (HR 0.21, 95% CI [0.111–0.407], p < .001) for failure. Conclusion AGV and ExP are safe and effective techniques in the treatment of ATTRv secondary glaucoma. However, AGV’s efficacy seems to be more durable.

Modeling of Explosive Pingo-like Structures and Fluid-Dynamic Processes in the Arctic Permafrost: Workflow Based on Integrated Geophysical, Geocryological, and Analytical Data

Understanding the mechanisms responsible for the origin, evolution, and failure of pingos with explosive gas emissions and the formation of craters in the Arctic permafrost requires comprehensive studies in the context of fluid dynamic processes. Properly choosing modeling methods for the joint interpretation of geophysical results and analytical data on core samples from suitable sites are prerequisites for predicting pending pingo failure hazards. We suggest an optimal theoretically grounded workflow for such studies, in a site where pingo collapse induced gas blowout and crater formation in the Yamal Peninsula. The site was chosen with reference to the classification of periglacial landforms and their relation to the local deformation pattern, according to deciphered satellite images and reconnaissance geophysical surveys. The deciphered satellite images and combined geophysical data from the site reveal a pattern of periglacial landforms matching the structural framework with uplifted stable permafrost blocks (polygons) bounded by eroded fractured zones (lineaments). Greater percentages of landforms associated with permafrost degradation fall within the lineaments. Resistivity anomalies beneath pingo-like mounds presumably trace deeply rooted fluid conduits. This distribution can be explained in terms of fluid dynamics. N–E and W–E faults, and especially their junctions with N–W structures, are potentially the most widely open conduits for gas and water which migrate into shallow sediments in the modern stress field of N–S (or rather NEN) extension and cause a warming effect on permafrost. The results obtained with a new workflow and joint interpretation of remote sensing, geophysical, and analytical data from the site of explosive gas emission in the Yamal Peninsula confirm the advantages of the suggested approach and its applicability for future integrated fluid dynamics research.

A competing risks model to estimate the risk of graft failure and patient death after kidney transplantation using continuous donor-recipient age combinations

Graft failure and recipient death with functioning graft are important competing outcomes after kidney transplantation. Risk prediction models typically censor for the competing outcome thereby overestimating the cumulative incidence. The magnitude of this overestimation is not well described in real-world transplant data. This retrospective cohort study analyzed data from the European Collaborative Transplant Study (n = 125 250) and from the American Scientific Registry of Transplant Recipients (n = 190 258). Separate cause-specific hazard models using donor and recipient age as continuous predictors were developed for graft failure and recipient death. The hazard of graft failure increased quadratically with increasing donor age and decreased decaying with increasing recipient age. The hazard of recipient death increased linearly with increasing donor and recipient age. The cumulative incidence overestimation due to competing risk-censoring was largest in high-risk populations for both outcomes (old donors/recipients), sometimes amounting to 8.4 and 18.8 percentage points for graft failure and recipient death, respectively. In our illustrative model for posttransplant risk prediction, the absolute risk of graft failure and death is overestimated when censoring for the competing event, mainly in older donors and recipients. Prediction models for absolute risks should treat graft failure and death as competing events.

Monitoring Slope Movement and Soil Hydrologic Behavior Using IoT and AI Technologies: A Systematic Review

Landslides or slope failure pose a significant risk to human lives and infrastructures. The stability of slopes is controlled by various hydrological processes such as rainfall infiltration, soil water dynamics, and unsaturated soil behavior. Accordingly, soil hydrological monitoring and tracking the displacement of slopes become crucial to mitigate such risks by issuing early warnings to the respective authorities. In this context, there have been advancements in monitoring critical soil hydrological parameters and slope movement to ensure potential causative slope failure hazards are identified and mitigated before they escalate into disasters. With the advent of the Internet of Things (IoT), artificial intelligence, and high-speed internet, the potential to use such technologies for remotely monitoring soil hydrological parameters and slope movement is becoming increasingly important. This paper provides an overview of existing hydrological monitoring systems using IoT and AI technologies, including soil sampling, deploying on-site sensors such as capacitance, thermal dissipation, Time-Domain Reflectometers (TDRs), geophysical applications, etc. In addition, we review and compare the traditional slope movement detection systems, including topographic surveys for sophisticated applications such as terrestrial laser scanners, extensometers, tensiometers, inclinometers, GPS, synthetic aperture radar (SAR), LiDAR, and Unmanned Aerial Vehicles (UAVs). Finally, this interdisciplinary research from both Geotechnical Engineering and Computer Science perspectives provides a comprehensive state-of-the-art review of the different methodologies and solutions for monitoring landslides and slope failures, along with key challenges and prospects for potential future study.

A hybrid spatiotemporal distribution forecast methodology for IES vulnerabilities under uncertain and imprecise space-air-ground monitoring data scenarios

The weak spots in an integrated energy system that may jeopardize the overall reliability call for timely and efficient Inspection and Maintenance (I&M). One core step is the reasonable allocation and deployment of limited I&M personnel or apparatus to the regions or periods with higher event risks, which requires a pinpoint spatiotemporal distribution forecast of future vulnerabilities. This paper presents a hybrid forecast methodology, the Saliency-Rough Fuzzy Utility Pattern recognition ensemble, in light of space-air-ground multi-source-heterogeneous input data. A parallel learning architecture is established and identifies the critical components with higher yields to enhance efficiency. Accordingly, more reasonable quantitative and qualitative evaluations can be carried out concurrently. Potential imprecise and uncertain data scenes are handled in quantitative assessments, both the failure hazard path sets and survival function likelihood boxes are incorporated in the designed relative path-Fussell Vesely Saliency (rp-FVS) model; and in qualitative analyses, the underlying perilous components can be distinguished via a combination of the variable precision-rough model. The rp-FVS-based fuzzy inference logic configures all membership functions identically according to components’ impacts. These two parts are integrated into the rough-fuzzy Utility Measure to discover concealed component-vulnerability interconnection patterns. Finally, an empirical case study is conducted for validation.

Analysis dam failure and flood inundation mapping: a case study of Manbaa-Al-Ghozlan dam, Biskra, Algeria

Floods in all their form are considered a real threat to many regions of the world. There are various types of floods, including those caused by the collapse of dams, which must be predicted to mitigate their effects. One of the non-structural solutions for flood mitigation and control is drawing the dam failure hazard map using effective and accurate flood models, which are essential for flood disaster prevention and mitigation. The study aims at the delineation of the flood plain area caused by Manbaa-Al-Ghozlan dam failure in the city of Biskra (About 40 km downstream the dam) and the surrounding communities (the village of El Outaya). Two scenarios were considered and simulated using the HEC-RAS 2D (River Analysis System) software, the first one is related to the sudden collapse of the dam and the second linked to under-evaluations of the projected flood of the dam spillway. The results of the first scenario confirmed that there are no risks threatening the city of Biskra taking into account the water depth which reached 5 meters in the city of El Outaya. Conversely, the water depth varying between 16m and 40m in the city of El Outaya and can exceed 16 meters in the city of Biskra for the second scenario, and this performs as a great danger for the zone. This simulation allowed designing the dam failure hazards map, which showed the areas threatened by flood waves, and consequently required a plan of security measures to moderate as much as possible the consequences of a dam collapse.

Hazard of Failed Nonoperative Management for Symptomatic Accessory Navicular in Children and Adolescents: A Population-Based Case-Cohort Study.

The accessory navicular (AN) is an idiopathic condition of the foot present in 4% to 21% of the population. Most ANs remain asymptomatic, but children and adolescents who develop symptoms can have remarkably reduced quality of life. Although many respond to conservative measures, surgery is occasionally needed. Our purpose was to determine factors associated with the failure of nonoperative management. This single-institution retrospective case-cohort study included patients up to age 19 years presenting between 2000 and 2021 with symptomatic AN and treated with standard-of-care. All 298 surgical cases, indicating failed nonoperative treatment, were included. For the subcohort, 299 patients were randomly sampled from all eligible patients, regardless of treatment. Baseline characteristics were summarized for the surgical cases and subcohort. Proportional hazards assumptions were checked and stratification implemented when necessary. Marginal structural proportional hazard modeling was used to estimate hazard ratios with 95% confidence intervals via inverse probability and LinYing weighting methods. The 298 surgical cases failed nonoperative management at a median of 5.2 months (IQR, 2.0-11.6 mo). In the subcohort, 86 failures of nonoperative management and 213 nonfailures constituted a 28.8% surgery rate. In both cohorts, nearly all patients played sports. Univariate proportional hazard modeling found older age ( P =0.02) and activity limitation ( P <0.001) at presentation, female sex ( P =0.002), higher BMI ( P =0.01), AN on the right ( P <0.001), and bone marrow edema of the AN ( P <0.001) and navicular body ( P <0.001) on MRI were associated with increased hazard of nonoperative failure. Nearly all of the surgical cohort reported improvement in pain (278/296, 94%) and returned to their primary sport (236/253, 93%) after surgery. Most also experienced full resolution of symptoms (187/281, 67%). Symptomatic AN predominantly affects female athletes, leading to surgery in 28.8% of our subcohort. Conservative treatment may be less successful-and therefore surgery could be more strongly considered-in older age, activity limitation at presentation, female sex, higher BMI, right-sided AN, and bone marrow edema on MRI. Surgery is effective for symptomatic and functional improvement. Case-cohort-Level III.

The Behavior of Concrete Cantilever Retaining Walls During Far-Field and Near-Fault Earthquakes

Abstract The dynamic behavior of retaining walls is a complicated subject and a considerable design challenge, particularly under seismic conditions. Seismologists and investigators have an interest in near-fault earthquakes with significant velocity pulses because it can cause considerable displacements in constructions with respect to far-field earthquakes and consequently rise the hazard of earthquake-caused failure of structures. Despite there are several studies have investigated the seismic behavior of retaining structures, but the researches about retaining walls subjected to the influence of near fault like pulse earthquakes is still not adequate. The current study targets to numerically assess the dynamic performance of concrete cantilever retaining walls during far field ground motions (FFGMs) and near-fault ground motions (NFGMs). The nonlinear analysis of time history is conducted using the finite element method for three cantilever retaining wall models. The results of the analysis gained in terms of top horizontal displacement of the wall, active seismic earth pressure, and acceleration response of the system, which have been considered to recognize the impact of near fault earthquake on retaining structures. Additionally, the influence of different PGA of NF and FF earthquakes has been studied.

An enhanced strategy for new energy generation black-start based on hybrid energy storage system

Abstract In the past few years, the connection of extensive power grids with a substantial influx of renewable energy has resulted in a growing hazard of significant power failures. Conventional black-start systems are inadequate in promptly and adaptively recuperating from such outages. Consequently, the emergence of new energy generation integrated with energy storage technology to deliver black-start services has become a prevailing trajectory. In this research article, hybrid energy storage is implemented for the wind and solar power generation system to address the issue of inadequate inertia support capacity during the black-start process. The system incorporates a virtual synchronizer to manage and replicate its inertia and damping features, thereby enhancing the black-start capability of renewable energy generation. The effectiveness of the proposed strategy is verified through simulation in Matlab/Simulink.

Risk assessment of organ transplant operation: A fuzzy hybrid MCDM approach based on fuzzy FMEA.

Nowadays, most fatal diseases are attributed to the malfunction of bodily. Sometimes organ transplantation is the only possible therapy, for instance for patients with end-stage liver diseases, and the preferred treatment, for instance for patients with end-stage renal diseases. However, this surgical procedure comes with inherent risks and effectively managing these risks to minimize the likelihood of complications arising from organ transplantation (maximizing life years from transplant and quality-adjusted life years) is crucial. To facilitate this process, risk ranking is used to identify and promptly address potential risks. Over recent years, considerable efforts have been made, and various approaches have been proposed to enhance Failure Modes and Effects Analysis (FMEA). In this study, taking into account the uncertainty in linguistic variables (F-FMEA), we introduce an approach based on Fuzzy Multi Criteria Decision Making (F-MCDM) for effectively evaluating scenarios and initial failure hazards. Nevertheless, the results of ranking failure modes generated by different MCDM methods may vary. This study is a retrospective study that suggests a comprehensive unified risk assessment model, integrating multiple techniques to produce a more inclusive ranking of failure modes. Exploring a broad spectrum of risks associated with organ transplant operations, we identified 20 principal hazards with the assistance of literature and experts. We developed a questionnaire to examine the impact of various critical factors on the survival of transplanted organs, such as irregularities in immunosuppressive drug consumption, inappropriate dietary habits, psychological disorders, engaging in strenuous activities post-transplant, neglecting quarantine regulations, and other design-related factors. Subsequently, we analyzed the severity of their effects on the durability of transplanted organs. Utilizing the Mamdani algorithm as a fuzzy inference engine and the Center of Gravity algorithm for tooling, we expressed the probability and severity of each risk. Finally, the failure mode ranking obtained from the F-FMEA method, three fuzzy MCDM methods, and the proposed combined method were identified. Additionally, the results obtained from various methods were evaluated by an expert team, demonstrating that the highest consistency and effectiveness among different methods are attributed to the proposed method, as it achieved a 91.67% agreement with expert opinions.

Mechanical failure of distal femur mega prosthesis due to polyaryl-ether-ether-ketone (PEEK) hinge component

BackgroundPolyaryl-ether-ether-ketone (PEEK) has gained popularity as a substrate for orthopaedic hardware due to its desirable properties such as heat and deformation resistance, low weight, and ease of manufacturing. However, we observed a relatively high failure rate of PEEK-based hinges in a distal femur reconstruction system. In this study, we aimed to evaluate the proportion of patients who experienced implant failure, analyse the mechanism of failure, and document the associated clinical findings.MethodsWe conducted a retrospective cohort study, reviewing the medical charts of 56 patients who underwent distal femur resection and reconstruction with a PEEK Optima hinge-based prosthesis between 2004 and 2018. Concurrently, we performed a clinical and biomechanical failure analysis.ResultsPEEK component failure occurred in 21 out of 56 patients (37.5%), with a mean time to failure of 63.2 months (range: 13–144 months, SD: 37.9). The survival distributions of PEEK hinges for males and females were significantly different (chi-square test, p-value = 0.005). Patient weight was also significantly associated with the hazard of failure (Wald’s test statistic, p-value = 0.031).DiscussionOur findings suggest that PEEK hinge failure in a distal femur reconstruction system is correlated with patient weight and male gender. Retrieval analysis revealed that failure was related to fretting and microscopic fractures due to cyclic loading, leading to instability and mechanical failure of the PEEK component in full extension. Further assessment of PEEK-based weight bearing articulating components against metal is warranted.