Type Of Failure Research Articles

Prognostic nutritional index as a predictor of mortality among patients admitted to ICU with acute exacerbation of chronic obstructive pulmonary disease

BackgroundThe PNI is a metric that may assess the combined impact of the inflammatory process and nutritional condition. It may be beneficial in evaluating the nutritional state of patients with AECOPD.In recent years, it has also been utilized for prognostic assessment of cases admitted to the critical care unit.Aim of the workThe objective of the research was to assess the relationship between PNI and the prognosis for ICU patients with AECOPD.Patients and methodsThis was a prospective cross-sectional observational research carried out in the RICU of Ain Shams University Hospitals from April 2023 to March 2024. The study included 161 AECOPD patients who were admitted to RICU. All patients underwent demographic data collection, special habits and comorbid conditions evaluations, and hematological indices with laboratory markers and ABG. ICU and hospital stay duration, SOFA score, and SAPS II were also documented. The PNI value was computed using the following equation: the formula to calculate the value is 10 times the serum albumin concentration in grams per deciliter plus 0.005 times the total lymphocyte count in cubic millimeters. The main measure of interest was the death rate within 30 days for all causes. Additional measures were the duration of stay in the ICU, the duration of hospitalization, and the rate of MV.ResultsThere was a significant relationship between PNI and type of respiratory failure, mechanical ventilation, fate, hypertension, and diabetes. One hundred five (65.2%) of the patients were extubated and discharged, while 56 (34.8%) of them died. The study also noted a significant positive relationship among PNI and HCT, lymphocytic %, HB, and albumin. However, there was a significant negative relationship between PNI and age, RDW, WBC, neutrophil count, neutrophil %, NLR, CRP, SAPSII, and SOFA. The SAPS II score (with SAPS II mortality) had greater AUROC in predicting mortality than PNI, NLR, and SOFA. The optimal cut-off value for PNI in this study was ≤ 29 with sensitivity 82.14% and specificity 56.19%.ConclusionThe study showed that PNI can be a useful biomarker for AECOPD. PNI with SAPS II scores on admission to ICU were closely correlated to adverse outcomes.

Formability and Failure Mechanisms of Continuous Glass Fiber-Reinforced Polypropylene Composite Laminates in Thermoforming Below the Melting Temperature.

In this study, the thermoforming formability of continuous glass fiber-reinforced polypropylene (CGFRPP) laminates below the melting temperature were investigated. The forming limits of CGFRPP laminates were explored using flexural tests, Erichsen tests and deep drawing tests. The failure mechanism of CGFRPP in thermoforming was investigated by observing typical failure specimens using a microscope. The results show that the flexural performance and Erichsen performance are optimal at 130 °C and 2 mm/min. At 160 °C and 100 mm/min, the deep drawing performance is optimal. The restriction of fibers by the matrix is affected by the deformation temperature, and the creation of defects is affected by the deformation rate. During forming, the CGFRPP laminates undergo shear and extrusion deformations, resulting in wrinkles, delamination, and fiber aggregation.

Evaluation of Wear on Primary Tooth Enamel and Fracture Resistance of Esthetic Pediatric Crowns Manufactured from Different Materials

Background and Objectives: Advances in dental materials and CAD-CAM technology have expanded crown options in primary teeth due to their improved appearance and mechanical properties. Thus, this study aimed to assess the enamel wear and fracture resistance of prefabricated, milled, and 3D-printed esthetic pediatric crowns. Materials and Methods: The study involved 60 extracted maxillary second primary molars and 60 3D-printed resin dies, divided into six groups based on different crown materials (n = 10): prefabricated zirconia, prefabricated composite, milled composite, milled resin matrix ceramic, milled PEEK, and 3D-printed resin. Prefabricated crowns were selected after the preparation of the typodont mandibular second primary molar tooth, while milled and 3D-printed crowns were custom produced. The specimens underwent mechanical loading of 50 N at 1.6 Hz for 250,000 cycles with simultaneous thermal cycling. The 3D and 2D wear amounts were evaluated by scanning the specimens before and after aging. Then, the fracture resistance and failure types of the restorations were recorded. Results: The results showed that the milled PEEK group had superior fracture resistance compared to the other groups, while prefabricated zirconia crown group had the lowest value. Milled resin matrix ceramic crown group displayed the lowest 3D wear volume, while 3D-printed crown group showed the highest 2D wear. Conclusions: The restorative material type did not have a significant effect on the wear of primary tooth enamel. The fracture resistance of the tested materials differed according to the material type. Although the milled PEEK group showed the highest fracture resistance, all tested materials can withstand chewing forces in children.

A systematic review of fault tolerance techniques for smart city applications

Smart City Applications encompass many characteristics that increase the risk of failures, such as context-awareness, adaptiveness, distribution and heterogeneity. Therefore, it is important to implement fault-tolerant mechanisms to produce more reliable applications. This study presents a systematic literature review of fault tolerance techniques that have been proposed for, or applied to Smart City Applications. It also characterizes faults, errors and failures that may occur in these systems. To the best of our knowledge, this is the first review that provides a broad picture of the research area and points out research limitations and directions. We selected 43 primary studies and performed initial classifications (e.g., based on type of research, type of contribution, application domains and subdomains, and type of system architecture). We further classified and discussed the selected studies based on types of fault tolerance techniques and types of faults and failures. System Reconfiguration, Diversity, and Retry are classical techniques that have been investigated in this domain. Many fault and failure types have also been addressed. While those well-known techniques have been explored for introducing fault tolerance capabilities into Smart City Applications, others have been overlooked. Moreover, evidence on the effectiveness and applicability of the proposed fault tolerance solutions is still very limited.Editor’s note: Open Science material was validated by the Journal of Systems and Software Open Science Board.

Hierarchical Classification of Factors Associated With Noninvasive Prenatal Testing Failures and Its Impact on Pregnancy Outcomes

Abstract Objective To conduct a hierarchical classification analysis of the nonreportable results of noninvasive prenatal testing in an attempt to reduce failure rates and provide pregnant women with accurate information to alleviate their anxiety. Methods In this study, 30,039 singleton pregnancies who underwent noninvasive prenatal testing in a single center from May 2019 to April 2022 were collected, and 811 samples with initial noninvasive prenatal testing failure were retrospectively analyzed. Grouping was based on the reasons for initial test failure; tracking the noninvasive prenatal testing results and prenatal diagnosis results (if any) of the “z-scores in the gray area” group and analyzing the possible influencing factors of the “low fetal fraction” group in the pre-experimental and experimental period by using one-way analysis of variance, Mann-Whitney U test, and χ2 test; and tracking the pregnancy outcomes of the test failures samples to analyze the risk of perinatal complications and adverse pregnancy outcomes of the different types of test failures. Results None of the samples' initial nonresults because of z-scores in the gray area were ultimately found to have chromosomal aneuploidy. However, pregnancy complications (P = 0.018) and a high likelihood of adverse pregnancy outcomes (P = 0.048) may still occur. Maternal gestational age (P < 0.001), body mass index (P < 0.001), library concentration (P < 0.001), and fetal gender (P < 0.001) were considered to be the associated factors for the initial low fetal fraction results. This may be associated with pregnancy complications (P < 0.001) and a high likelihood of adverse pregnancy outcomes (P = 0.034). The body mass index (P = 0.015) and time between draws (P = 0.001) were associated with the second test’s success. The incidence of low fetal fraction samples was more frequent with blood collection tubes of the G type than with the K type (P < 0.001). Conclusion Initial nonresults because of z-scores in the gray area did not imply an increased risk of aneuploidy, but vigilance is needed for an increased risk of pregnancy complications and adverse pregnancy outcomes. Because of the low fetal fraction, the initial absence of results may be related to the assay method, as well as the effect of blood collection tubes and the need to be alert to the risk of pregnancy complications and adverse pregnancy outcomes.

Effect of double adhesive layer application on micro-tensile dentin bond strength of a universal adhesive

IntroductionAchieving optimal dentin bond strength is crucial for the long-term success of adhesive restorations. This study aims to evaluate the impact of double adhesive layer application, with and without light curing between applications, on the micro-tensile dentin bond strength (µ-TBS) of a universal adhesive, in comparison to the conventional single-layer application.MethodsIntact human molars were divided into three groups (n = 15) according to the adhesive application technique using a universal self-etch adhesive (Tetric N-Bond Universal, Ivoclar) as follows: (1) according to the manufacturer's instructions, (2) double-layer application without light curing between layers, and (3) double-layer application with light curing between layers. Samples were immediately tested for µ-TBS, with failure types recorded as adhesive, cohesive, or mixed. Representative samples were observed by scanning electron microscopy. Data were analyzed using multiple-way ANOVA (α = 0.05).ResultsThe double adhesive layer with and without light curing between layers showed similar μ-TBS to that of the control group (p > 0.05).DiscussionFrom a clinical perspective, these findings suggest that the accurate application of a single layer of a universal adhesive can be as effective as more complex techniques. Additionally, the use of universal bonding agents may have contributed to the outcomes observed in this study. In conclusion, double adhesive layer application and light curing between adhesive layers did not increase the µ-TBS with the universal adhesive agent explored.

Blind prediction and post-experimental analysis of RC core wall’s cyclic flexural response using MVLEM-FD

AbstractBlind prediction and post-experimental studies of the flexural cyclic response of a U-shaped core wall, tested at UCLouvain, Belgium, are presented. The tested specimen (referred to as UW1) was modelled using a relatively simple 3D force–displacement-based version of the beam–column multiple-vertical-line-element (MVLEM-FD), developed at the University of Ljubljana (UL), using standard element parameters. The blind prediction accurately identified critical failure points within the specimen. However, the predicted type of failure, attributed to the rupture of longitudinal bars in the boundary region of flanges was somewhat different from that observed in the experiment. These bars were indeed ruptured, but their rupture was preceded by their buckling and the spalling of the surrounding concrete core. Moreover, the predicted force–displacement hysteretic loop exhibited a slight shift compared to experimental observations. Post-experimental studies revealed that this discrepancy was primarily due to the modelling of the loading at the top of the wall rather than the modelling of the wall itself. Specifically, an additional bending moment induced by the eccentricity of the vertical load applied using three actuators, which was overlooked in the blind prediction. Upon correcting the loading, the agreement between the numerical studies and experiment was considerably improved in terms of both the global and local response quantities. Additionally, minor improvements in modelling the boundary regions of the wall’s flanges, considering the relatively large unconfined concrete cover, were introduced, leading to enhanced estimations of near-collapse response.

Impact performance of egg‐box core sandwich panels made from sisal fibers and castor‐oil‐based polymer

AbstractDeveloping sustainable composites for engineering applications is essential for minimizing environmental impacts and ensuring the long‐term viability of infrastructure and technological advancements. In this context, this work focuses on the manufacture and evaluation of the structural integrity of a sandwich structure composed of aluminum faces and egg‐box‐shaped, sisal fiber‐reinforced epoxy (SFE) or castor‐oil polyurethane (SFC‐O) composites. The sandwich panel is filled with a biobased foam and subjected to dynamic load (drop‐tower) test. For comparison, the base materials SFE and SFC‐O molded into the egg‐box‐shaped cores are also evaluated using Charpy impact tests to establish a potential correlation between their Charpy performance and the drop‐tower behavior of egg‐box sandwich structures. The findings reveal that SFC‐O laminates demonstrate superior Charpy impact resistance (~49%) compared to SFE laminates. Similarly, sandwich structures composed of egg‐box‐castor‐oil composite cores absorb approximately 42.5% more energy than those made with egg‐box‐epoxy cores. The impact behavior of the sandwich structures correlates directly with the impact resistance of the sisal fiber laminates. Overall, the results indicate that the castor‐oil polymer can effectively replace the epoxy polymer matrix phase, enhancing impact absorption and providing an environmentally correct and sustainable solution for fabricating sandwich panels.Highlights Castor‐oil polymer provides laminates with lower density relative to epoxy. Sisal‐castor‐oil‐based laminates possess higher impact resistance than those based on epoxy. Sisal‐castor‐oil‐based panels achieve higher absolute and specific drop‐tower impact properties. Panels subjected to drop‐tower impact tests reveal skin delamination, wrinkling and indentation. Debonding between the foam and egg‐box core is a typical failure mode for epoxy sandwich panels.

Role of Na+-K+ ATPase Alterations in the Development of Heart Failure.

Na+-K+ ATPase is an integral component of cardiac sarcolemma and consists of three major subunits, namely the α-subunit with three isoforms (α1, α2, and α3), β-subunit with two isoforms (β1 and β2) and γ-subunit (phospholemman). This enzyme has been demonstrated to transport three Na and two K ions to generate a trans-membrane gradient, maintain cation homeostasis in cardiomyocytes and participate in regulating contractile force development. Na+-K+ ATPase serves as a receptor for both exogenous and endogenous cardiotonic glycosides and steroids, and a signal transducer for modifying myocardial metabolism as well as cellular survival and death. In addition, Na+-K+ ATPase is regulated by different hormones through the phosphorylation/dephosphorylation of phospholemman, which is tightly bound to this enzyme. The activity of Na+-K+ ATPase has been reported to be increased, unaltered and depressed in failing hearts depending upon the type and stage of heart failure as well as the association/disassociation of phospholemman and binding with endogenous cardiotonic steroids, namely endogenous ouabain and marinobufagenin. Increased Na+-K+ ATPase activity in association with a depressed level of intracellular Na+ in failing hearts is considered to decrease intracellular Ca2+ and serve as an adaptive mechanism for maintaining cardiac function. The slight to moderate depression of Na+-K+ ATPase by cardiac glycosides in association with an increased level of Na+ in cardiomyocytes is known to produce beneficial effects in failing hearts. On the other hand, markedly reduced Na+-K+ ATPase activity associated with an increased level of intracellular Na+ in failing hearts has been demonstrated to result in an intracellular Ca2+ overload, the occurrence of cardiac arrhythmias and depression in cardiac function during the development of heart failure. Furthermore, the status of Na+-K+ ATPase activity in heart failure is determined by changes in isoform subunits of the enzyme, the development of oxidative stress, intracellular Ca2+-overload, protease activation, the activity of inflammatory cytokines and sarcolemmal lipid composition. Evidence has been presented to show that marked alterations in myocardial cations cannot be explained exclusively on the basis of sarcolemma alterations, as other Ca2+ channels, cation transporters and exchangers may be involved in this event. A marked reduction in Na+-K+ ATPase activity due to a shift in its isoform subunits in association with intracellular Ca2+-overload, cardiac energy depletion, increased membrane permeability, Ca2+-handling abnormalities and damage to myocardial ultrastructure appear to be involved in the progression of heart failure.

Wear load analysis of conical cutter crushing rock based on SPH to SPH interaction method

Wear is the main failure type for conical cutters. The main load causing its wear is difficult to measure in the test, and the existing simulation models cannot simulate the wear load. Thus, the three-dimensional dynamic model for conical cutter crushing rock is established based on the SPH-SPH interaction method to analyze the relationship between the cutting performance factors and cutter wear. The factors are taken into account such as the stress distribution of rock, kinetic energy and internal energy and displacement of rock, cutting load of cutter, stress of cutter. Then, it is studied that the effect of cutting angle on the cutting performance parameters such as specific energy consumption, rock avalanching, cutting load, load fluctuation, cutter tip stress and cutter side stress. Finally, the cutting angle selection reference of the cutter is given under different consideration factors.

The strength of stance: The impact of brand activism on resistance to negative information, purchasing, and premium paying intents across different types of failures

This paper represents a pioneering exploration of how brand activism influences consumer responses to performance and value-related failures. Specifically, across two experiments, the research explores how brand activism influences consumer resistance to negative information, purchase intent, and willingness to pay more, in response to product, service, and value-related failures. Study 1 (N = 237) reveals that consumers who are more involved in activism and are exposed to a product failure from activist brands exhibit higher resistance to negative information compared to those who encounter product failures from non-activist brands. This suggests that activist branding may protect companies by cultivating a resilient, loyal consumer base in such adverse situations. Study 2 (N = 261) extends these findings by examining whether value-related (vs service-related) failures impact the buffering effect generated by a brand’s activist stance. Results indicate that activist brands particularly benefit from a protective buffer in the context of service failure scenarios. However, this buffer does not extend to value-related failures, leading to harsher consumer judgments and intentions. The research significantly contributes to brand activism literature by uniquely integrating the themes of brand activism and brand transgressions, exploring how brand activism affects consumer responses to both performance and value-related failures.

In-vitro comparison of fracture resistance of CAD/CAM porcelain restorations for endodontically treated molars

BackgroundThis study evaluates the fracture strength and patterns of feldspathic porcelain restorations made using CAD/CAM technology for lower first molars with extensive crown destruction. The restorations include post-core and full-contour crown, composite resin core and full-contour crown, and endocrown. This research provides insights into effective restorative options to address tooth fracture risk, supporting minimally invasive procedures and CAD/CAM integration in dental practices.MethodsThis study utilized 80 permanent mandibular first molars, which were divided into four groups: Group I (Post-Core-Full-contour crown), Group II (Core- Full-contour crown), Group III (Endocrown), and Group IV (Control). Root canal treatment was performed on all samples except for the control group. Following access cavity preparation, restorations for each tooth were fabricated using the CAD/CAM system and cemented with resin cement. The specimens were embedded in acrylic blocks. After undergoing thermomechanical aging, the samples were subjected to fracture resistance testing using a universal testing machine, which applied force until fracture occurred. The fracture patterns were subsequently analyzed, and the data were statistically evaluated using the Kruskal-Wallis and Chi-Square tests (p < 0.05).ResultsA significant difference in fracture values under axial forces was observed (p < 0.05). The control group had the highest fracture strength (1830 ± 277 N), while the Core- full-contour crown group showed the lowest (1532 ± 371 N). Failure types varied significantly among the groups (χ2 = 26.886, df = 9, p = 0.001). The most common failure type was Type-2 (33.75%), characterized by restorable fractures, while Type-3 fractures, unrestorable, were the least common (12.5%).ConclusionsThe findings underscore the significance of technological advancements in CAD/CAM for effectively restoring endodontically treated teeth with extensive crown damage. This study contributes valuable insights, emphasizing the clinical relevance of selecting appropriate restorative options to mitigate the risk of tooth fracture associated with coronal restoration failures.

Web-Based Maintenance Prediction of Machine Conditions and Failure Modes Using Machine Learning

Machine failure may result in unplanned downtime, production losses, safety risks, and increased costs. Hence, predicting machine failures is a significant challenge faced by many industries. Predictive Maintenance (PdM) techniques can help mitigate these risks by predicting machine failures before they occur. This research, therefore, develops two supervised Machine Learning (ML) algorithms to predict failure conditions and the associated failure modes for a milling machine. Six machine features were investigated. The ML models were then developed using a four-stage process including data pre-processing, training, evaluation, and deployment. Several ML algorithms were applied then the results were evaluated using accuracy, recall, precision, and [Formula: see text]1-score. The results showed that the Random Forest algorithm was the most effective in predicting machine conditions and failure modes of the milling machine. A web application for PdM was finally developed and tested for the PdM of the milling machine. In conclusion, the developed web application including ML algorithms can support the effective PdM for the machine, which leads to enhancing its availability and improving productivity. Future research considers adopting ML algorithms for predicting machine conditions and failure types of other machines.

When failure is the option: Unravelling sexual assault outcomes

We investigate the concept of “criminal failure” in sexual crimes and the relevance of various theoretical frameworks for its understanding: individual offender's rational choice, environmental influences and routine activities, victimological characteristics from lifestyle theory, and crime interaction factors. We examined a sample of 1121 “failed” cases (i.e., attempted but not completed) and 1500 “successful” cases (i.e., completed) of sexual assault that occurred in France between 1990 and 2018. We used 32 predictors that mapped on the four theoretical frameworks and conducted bivariate followed by multivariate analyses. Multiple theoretical frameworks are relevant to understand criminal failure, which is a product of perpetrator, environmental, victimological, and interactional factors. Two distinct patterns are specifically associated with failure: lack of preparation and lack of social skills. In addition, failure was best understood not as a unitary concept, but as multifactorial by distinguishing between different types of failure, specifically: offender intentionally released the victim before completion, victim escaped or third party rescue. Finally, patterns of failure were different in sexual crimes against children compared to those against adults. Criminology should pay closer attention to failure in crime. This understudied area can yield important theoretical knowledge and practical implications regarding the prevention of sexual crimes.

Investigation of diesel particulate filter performance under typical failure conditions

Diesel particulate filter (DPF) is one of the most effective particulate reduction components in diesel engine aftertreatment systems. However, prolonged utilization of a DPF might result in a deterioration in performance or even failure, such as ash-clogging, melting, breakage, and catalyst deactivation. It is crucial to conduct research on DPF performance degradation across a series of partially failed conditions. In this study, the morphology and chemical composition of the ash in the DPF samples were characterized. The effects of degree-varying clogging and unplugged-breakage failure on exhaust characteristics as well as DPF temperature, filtration and pressure drop characteristics were investigated. Finally, the sensitivity differences between DPF performance parameters and failure index parameters were examined using a canonical correlation analysis (CCA). When four factors were considered, the ash loading index and breakage index had the greatest impact on DPF temperature difference and filtration efficiency, while the exhaust mass flow rate had the greatest impact on pressure drop. Besides, the influence of the DPF inlet temperature on the pressure drop, filtration efficiency, and temperature difference was not significant. These findings contribute to the prediction of DPF performance in partially failed conditions and the development of DPF failure diagnosis methods.

The value of blood flow velocity and pressure gradient in differentiating patients with different types of heart failure.

Patients with different types of heart failure (HF) exhibit varying rates of blood flow through cardiac chambers and pressure gradients across the aortic valve, attributed to differing degrees of myocardial contractility. Assessment of these dynamics offers insights into early HF diagnosis. This study aimed to analyze left ventricular outflow tract (LVOT) blood flow parameters, specifically peak blood flow velocity and pressure gradient derived from four-dimensional flow cardiovascular magnetic resonance (4D flow CMR), and to evaluate 4D flow CMR's utility in distinguishing HF types. This prospective cross-sectional study recruited 115 HF patients from January 2019 to May 2022 at the General Hospital of Ningxia Medical University, classified by the New York Heart Association Cardiac Function Classification of Heart Failure as class II-IV, alongside a control group (n=30). Participants underwent cardiovascular magnetic resonance (CMR), including 4D flow. HF patients were categorized into heart failure with reduced ejection fraction (HFrEF, n=55), heart failure with mildly reduced ejection fraction (HFmrEF, n=30), and heart failure with preserved ejection fraction (HFpEF, n=30), based on ejection fraction. The cardiac functional parameters and aortic valve flow indices were measured using Circle Cardiovascular Imaging. LVOT 4D flow data were obtained 3 mm below the junction of the aortic valve leaflets, assessing peak velocities above and below the valve. Differences in cardiac function and blood flow parameters between groups were analyzed using one-way analysis of variance (ANOVA). The accuracy of these parameters in identifying subgroups was assessed using the receiver operating characteristic (ROC) curve. Analysis of conventional cardiac function parameters revealed that left ventricular ejection fraction (LVEF) was significantly lower in the HFrEF and HFmrEF groups compared to the HFpEF and control groups (P<0.01). Additionally, end-diastolic volume and end-systolic volume were significantly higher in the HFrEF and HFmrEF groups than in the HFpEF and control groups (P<0.01). However, there were no significant differences in cardiac function parameters between the HFpEF and control groups (P>0.05). Significant differences were observed in aortic valve peak pressure gradients (Supra-APGmax) among the four study groups (5.01±1.09 vs. 6.23±2.94 vs. 7.63±1.81 vs. 8.89±2.97 mmHg, P<0.05). Aortic valve peak velocities in the HFrEF group differed significantly from the HFpEF and control groups (111.31±12.05 cm/s vs. 137.2±16 vs. 147.15±24.55 cm/s, P<0.001). The ROC curve for the pressure gradient below the aortic valve had an area under the curve (AUC) of 0.728 [95% confidence interval (CI): 0.591-0.864, P=0.002], with an optimal threshold of 4.72 mmHg (sensitivity: 0.8, specificity: 0.7, Youden index: 0.5). HF patients exhibit reduced pressure gradients across the aortic valve during systole, indicative of altered intracardiac blood flow dynamics. Combining aortic valve velocities and pressure gradients can aid in distinguishing different types of HF, including HFpEF patients.

ECG Risk Score Model to Predict SCD in HFrEF: Retrospective Review in a Tertiary Centre

INTRODUCTION: Heart failure with reduced ejection fraction (HFrEF) patients need to be risk stratify as guidelines have shown that patients with left ventricularejection fraction (LVEF) &lt;35% could be prevented from sudden cardiac death (SCD) by insertion of prophylactic implantable cardioverter-defibrillator (ICD). Thus we conducted a retrospective single tertiary centre study to evaluate the used of electrocardiogram (ECG) risk score model in identifying the individuals who at higher risk of SCD. MATERIALS AND METHODS: A total of 356 heart failure with reduced ejection fraction (HFrEF) patients treated at University Malaya Medical Centre between January 2017 and December 2021 were enrolled into this study. The patients’ demographics, types of heart failure, medications, and ECG parameters data were collected. The study outcomes were survivor or death in and the cause of death were subdivided into SCD or non-sudden cardiac death (non-SCD). RESULTS: A total of 156 study patients were survivor whereas another 120 had SCD and 70 had non-SCD. There were six ECG parameters that remained significant in the final model, namely the bundle branch block (BBB), abnormal P waves, QRS duration, QTc duration, TpTe interval and PR interval. The significant ECG parameters were combined into a risk score to enumerate prediction ability towards SCD. From our ECG risk score model, subject with ≥2 ECG abnormalities had more than 3-fold increased risk for SCD (HR 3.739, 95% CI 1.703-8.211, P 0.001) and the risk proportionately increased with increasing ECG abnormalities. CONCLUSION: Our findings suggested that the cumulative ECG risk score model was independently associated with SCD and particularly effective for LVEF &lt;40% where risk stratification model remained scarce. So, we would like to propose for a prospective study to further evaluate our study outcome.

Experimental study on seismic performance of seismic-damaged precast steel reinforced (recycled) concrete frame structure after strengthened and repaired

In order to understand the seismic performance and failure mechanism of the seismic-damaged prefabricated steel (recycled) concrete frame after strengthening and repairing, this paper uses four different strengthened methods, including carbon fiber reinforced polymer (CFRP), high-strength steel wire cloth (HSSWC), oblique support and enveloped steel jacket. Four seismic-damaged prefabricated steel (recycled) concrete frames were strengthened by single or composite strengthening, and low-cycle reciprocating failure tests were carried out on all frame specimens. The final failure mode of the reinforced specimens under simulated seismic load was observed. The seismic performance indexes such as load-displacement (P-Δ) hysteresis curve, skeleton curve, and stiffness degradation of each specimen before and after strengthening were compared and analyzed. The test results show that the strengthening methods used in this test can effectively restore the seismic performance of the seismic-damaged prefabricated steel (recycled) concrete frame. The specimens show a typical ductile failure mode, and the P-Δ hysteresis curve of the specimens is relatively full. For a single strengthened form, CFRP strengthened can more significantly restore and improve the ductility of the specimen than HSSWC strengthened, but the cumulative energy dissipation capacity of the specimen after HSSWC strengthened is stronger. The bearing capacity of the specimens after composite-strengthened is significantly improved, and the damage degree of the structure is reduced. The addition of oblique support and an enveloped steel jacket can provide greater lateral stiffness for the specimens and improve the failure mode of the specimens. The results of this paper can provide a scientific basis for the selection and design of strengthened methods for prefabricated steel-reinforced concrete structures after earthquake damage.

Investigating the mechanical properties and crashworthiness of hybrid PLA/GFRP composites fabricated using FDM-filament winding

The failure and crashworthiness performance of hybrid Polylactide (PLA)/Glass Fiber Reinforced Polymer (GFRP) composite tubes subjected to axial and radial quasistatic compression loads were investigated in the present study. The composite tubes are fabricated using hand lay-up and Fused Deposition Modeling (FDM)-filament winding processes. The crashworthiness performance was studied using parameters such as the peak load, energy absorption, crush load, crushing load efficiency, and specific energy absorption. The highest peak loads from the compression test results in the axial and radial directions are calculated using variations in the filament winding PLA/GFRP (FPG) specimen, whose values were 16130.50 N and 12077.33 N, respectively. The highest mean crush load is found in the material variation with the FPG specimen, which is 5734.43 J/mm for axial loading and 4886.75 J/mm for radial loading. The highest energy absorption (EA) value is found in the material variation with the FPG specimen, which is 262.18 J for axial direction loading and 94.02 J for radial direction loading. The highest specific energy absorption (SEA) value is found in the material variation with the specimen Filament Winding PLA/GFRP, which is 16.92 J/g for axial loading and 10.98 J/g for radial loading. There are three main types of failure of the composite: matrix cracking, fiber damage, and folding. The study showed that by combining Additive Manufacturing and composite lamination, the hybrid PLA/GFRP specimen outperformed the existing structures.

Assessment of landslide Possibility Index and Rockfall Hazard Rating System for Slopes in Qaywan Mountain, Sulaimani Governorate, Northeastern Iraq

The current study includes assessing road risks using a system Landslide Possibility Index (LPI) and Rockfall Hazard Rating System (RHRS) analysis along the Qaywan Mountain (anticline) main road 20 km north of SulaimaniGovernorate. Slope stability assessments consisted of seventeen stations along the main road in the study area. Along the outcropped rock units represented by formations, Balambo, Sarmord, Kometan, and Shiranish, a thorough discontinuity assessment and a regional survey of slopes were carried out. Along the cut slopes, rockfall is the primary type of failure, in addition to possibility types of landslide failures in the studied area is plane sliding, wedge sliding, and toppling because cutting rocks to build roads, slope direction and slope angle, dip and dip direction of discontinuities. The (LPI) indicates all the slopes studied in 17 sites in the surveyed area along the road were classified as high hazard. According to the analysis results of the RHRS, the score ranges between 177 and 375. Site no. 5 (375) has the highest rating value indicating a moderate hazard that requires remedial measures to be taken with a moderate level of urgency and site no.8 has the lowest value noted (177). It is the only site that falls under this rating, which is classified as a low hazard and slopes do not require detailed studies.