Stages Of Failure Research Articles

Moderately Increased Left Ventricular Filling Pressure Suggesting Early Stage of Heart Failure with Preserved Ejection Fraction in Patients with Invasively Assessed Coronary Microvascular Dysfunction

Background: With modern diagnostic tools, incidence ischemia with no obstructive coronary atherosclerosis (INOCA) and heart failure with preserved ejection fraction (HFpEF) are found to be much higher than previously believed, and—as they lead to adverse cardiovascular outcomes—their causes and development are subjects of ongoing research. There is growing evidence that coronary microvascular dysfunction might be the underlying cause of both INOCA and HFpEF. Methods: In 65 patients with effort angina but no obstructive coronary artery disease, the index of microvascular resistance and coronary flow reserve were measured invasively in the LAD. The echocardiographic parameters, including left atrial strain, left ventricular strain, and indices of left ventricular diastolic dysfunction, were compared between two groups of patients: those with normal coronary microcirculation parameters and those with impaired coronary microvascular function. Results: Patients with coronary microvascular dysfunction had higher a E/E′ index than those with normal microvessel reactivity. This finding was further confirmed by ROC analysis. The groups did not differ significantly in values of other echocardiographic parameters, including the left ventricular and left atrial strain. The prevalence of classical cardiovascular risk factors was similar in both groups. Conclusions: The coexistence of impaired coronary microvascular function with moderately elevated left ventricular filling pressures might correspond to the co-development of early stages of coronary microvascular dysfunction and HFpEF.

Fracture mode classification of UHPC based on deep learning and wavelet time–frequency spectrum derived from acoustic emission waveform

Fracture mode categorization is essential in identifying the failure stage, evaluating the damage characteristics, and providing references for structural maintenance. Acoustic emission (AE), as a passive nondestructive technique, presents great potential in damage characterization of cementitious materials and structures. In this study, a convolutional neural network (CNN) and gated recurrent unit (GRU) integrated model for tensile, shear, and mixed cracking mode classification of ultra-high-performance concrete (UHPC) was proposed and verified based on AE waveform features. First, four-point bending and direct shear tests for UHPC specimens were carried out, respectively, to generate AE waveform signals corresponding to different cracking modes (tensile, shear, and mixed ones). Subsequently, the collected one-dimensional AE signals were converted into two-dimensional time–frequency spectrum by continuous wavelet transform. And an AE dataset was constructed after manual labeling based on the corresponding relationships between cracking modes and wavelet time–frequency spectra. Then, an automatic CNN-GRU automatic classification model was established using wavelet time–frequency spectrum images as input variables, where the CNN extracts spatial image features, and the GRU screens time dependencies and realizes final classification. The proposed CNN-GRU model achieves an accuracy of 96.17% for cracking mode classification of UHPC, which is superior both in computational accuracy and efficiency to lightweight CNN and AlexNet. Classification outcomes for UHPC specimen under four-point bending and direct shear tests revealed the proportion of tensile cracks progressively decreased with the increase of damage, while shear cracks exhibited the opposite trend. The percentage of mixed mode cracks maintained relatively stable throughout the failure stages. The model proposed in this study presents favorable performance to reveal the underlying damage evolution mechanism during UHPC fracture, which can also provide references for the cracking mode classification of other cementitious materials and structures.

Abstract 4137991: Association of the 2022 AHA/ACC/HFSA Heart Failure Staging and Cardiovascular and Kidney Outcomes in Patients with Diabetes and Kidney Disease: A Secondary Analysis of the SCORED Trial

Introduction: The 2022 AHA/ACC/HFSA heart failure (HF) classification newly incorporates cardiac biomarkers to identify patients at risk of HF. Research Question: Given shared risk factors between HF and other cardiorenal events, the HF stages may also guide prognosis and management of cardiovascular (CV) and kidney-related events beyond HF. Aims: Examine the association of HF stage with CV and kidney events. Methods: SCORED was a randomized trial in diabetes with kidney disease comparing sotagliflozin (sota) v. placebo on CV death, hospitalizations for HF, and urgent HF visits. SCORED participants were grouped by HF stage post hoc . Stage A: No HF, normal cardiac biomarkers (NT-proBNP; <125 pg/mL, hs-cTnT; <14 ng/L) and normal cardiac structure/function by echocardiography. Stage B (pre-HF): No HF but elevated NTproBNP, hsTNT or abnormal echocardiography. Stage C/D: symptomatic HF. Endpoints of interest included the primary composite endpoint (CV death and HF-related events), major adverse CV events (MACE), and kidney-related composites (See Figure caption). Using Cox regression, we examined the association between HF stage and these endpoints, and whether the effect of sota v. placebo varied by HF stage. Results: There were 741 patients in stage A, 6560 in stage B (pre-HF) and 3283 in stage C/D (established HF). The mean NTproBNP and hs-cTnT increased with HF stage. Stepwise increases in HF stage were associated with a 2-4 fold higher incidence of the primary, MACE and kidney endpoints in the placebo group, although the incidence of the kidney-specific composite was similar in stage B and C/D (Figure). The relative risk reduction with sota v. placebo for all endpoints was similar irrespective of HF stage (p-interaction>0.05), with higher absolute benefit in each HF stage (Figure). The absolute benefit for the kidney-specific endpoint was comparable for stage B and C/D. Conclusions: Increasing HF stage is associated with higher risk of HF, MACE, and kidney events, but the risk of kidney events is similar in stage B (pre-HF) and stage C/D (established HF). Sota has similar relative benefits for all endpoints, irrespective of HF stage, with a corresponding increase in absolute benefits at higher stages.

Effects of openings on postbuckling behavior of large‐size composite C‐beam under bending‐shear coupling load

AbstractProper design and accurate mechanical assessment of composite C‐beam after opening are of great importance in structure engineering. This paper aims to experimentally and analytically investigate the postbuckling response of large‐size C‐beam with web opening under bending‐shear coupling load. New specimen with four different open shapes were designed and tested. Strain gauges and displacement measurements were applied to monitor its buckling behavior, strain field distribution and critical failure load. Four specimens with various openings were loaded until catastrophic failure occurred. Additionally, an analytical model was introduced to predict the residual strength of circular opening. The results indicate that while the presence of an opening significantly decreases the load carrying capacity, it has minimal effect on the bending stiffness. Compared with intact specimen, the initial delamination, buckling and ultimate strength of the circular opening decreases less than those of the rectangular opening. By altering the position of the rectangular opening, improvements can be made in terms of initial delamination resistance and buckling load; however, ultimate strength remains largely unaffected. Reinforcing the edge of an opening further reduces resistance to initial delamination but other two indicators are improved. Overall, from buckling to failure stages, post‐buckling bearing capacity after opening decreases by 40%. Moreover, the shear failure mode is observed during catastrophic failures. And the analysis method employed is relatively conservative.Highlights Ten large size composite C beams are conducted under coupling loads. Deformation, strain distribution and failure mode are presented. Influence of openings on postbuckling behavior of beam is analyzed. An analysis method is employed to predict the residual strength of beam. It could provide valuable insights for assisting in designing beam openings.

Relationship between anthropometric indicators and respiratory muscle strength in chronic heart failure

Objective. To determine, according to anthropometry, caliperometry, and dynamometry, the parameters determining individual physical development and somatotypes, as well as to identify their relationship with the strength of the respiratory muscles (RM) in the initial and clinically pronounced stages of chronic heart failure (CHF) with a preserved left ventricular ejection fraction. Materials and methods. 58 patients of both sexes aged 45 to 72 years were examined. The patients were divided into two groups: the main group (patients with CHF) and the comparison group (patients without CHF). All patients underwent anthropometric measurements, caliperometry, and dynamometry. The strength of RM was determined. Statistical processing was carried out using nonparametric methods. The indicators were considered reliable at p < 0.05. Results. When determining somatotypes, a high incidence of endomorphic type was revealed in patients with CHF with a preserved left ventricular ejection fraction. The indices of RM strength did not significantly differ in both groups. The analysis of anthropometry parameters revealed high values in patients with weakness of inspiratory and expiratory muscles in CHF with preserved left ventricular ejection fraction. Conclusion. (1) Endomorphic somatotype was more common in patients with clinically pronounced CHF with preserved ejection fraction. (2) In the patients with CHF and RM weakness, the level of the N-terminal fragment of natriuretic cerebral propeptide was higher compared to the patients with CHF with a preserved fraction of the left ventricle with preserved RM strength (p = 0.05). (3) With an increase in the functional class of CHF, the tendency to decrease the strength of inspiratory muscles increases (F = 3,3; p = 0,027). (4) In all examined patients, a positive correlation was found between the strength of RM and the results of carpal dynamometry. In the CHF patients with preserved left ventricular fraction, anthropometry parameters correlated only with the maximum expiratory pressure (MEP), while those in patients without CHF correlated both with maximum inspiratory pressure (MIP) and MEP.

Study on the Mechanical Behavior of Top-Chord-Free Vierendeel-Truss Composite Slabs

A top-chord-free Vierendeel-truss composite slab (TVCS) comprises a concrete slab, several vertical webs, and a steel bottom chord. In this study, static tests and finite element analyses were conducted based on an actual project to investigate the deformation, crack characteristics, ultimate bearing capacity, and failure mode of the composite slab. The findings indicated that the loading process of this type of floor can be divided into elastic, elastoplastic, and failure stages. The section stress distribution in the elastic stage was further analyzed. The crack development pattern exhibited a fine density in the pure bending sections of the concrete slabs, while demonstrating good overall flexural bearing capacity and ductility for the composite slab. Experimental results were compared with the ANSYS finite element model simulation to validate the accuracy of the simulation. Parametric analysis was conducted to assess the impact of concrete strength, steel strength, vertical web width, and distance ratios on the mechanical characteristics of the composite slab. By introducing an adjustment coefficient for the vertical web distance ratio, a revised calculation formula for flexural bearing capacity was proposed, which aligned well with the finite element analysis.

Components of home-based palliative and supportive care for adults with heart failure: A scoping review.

Palliative care and supportive care provided in the home for people with heart failure can improve quality of life, caregiver wellbeing and reduce healthcare costs. Identifying components of home-based palliative and supportive care in heart failure is useful to inform tailored care to people with heart failure. To identify and describe components of home-based palliative and supportive care in adults with heart failure. A scoping review was undertaken in accordance with Joanna Briggs Institute guidelines. The protocol was registered prospectively with the Open Science Framework (https://doi.org/10.17605/OSF.IO/GHCME). Embase, PubMed, CINAHL and Cochrane databases were searched from inception in May 2023 and re-run in January 2024. Original research focussed on palliative and supportive care in the home setting that included adults diagnosed with heart failure who have not undergone nor awaiting a heart transplant was included. Results were extracted from 13 papers based on eight studies. The findings highlight that nurses supported by a multidisciplinary team, providing symptom management, patient and carer education and discussion of goals of care and advance care planning, facilitates home-based palliative and supportive care for people with heart failure. Ensuring patient and caregiver-centred care supported by a multidisciplinary team is essential to delivering home-based palliative and supportive care for people with heart failure. Further research focussed on the role of digital interventions in home-based palliative and supportive care, the composition of the multidisciplinary team and research which includes individuals across all stages of heart failure is needed.

Cox Regression Model with Time-varying Coefficients Applied to Survival Estimation of Heart Failure

This study focuses on survival analysis of heart failure patients. All the patients, who are over 40 years old, have NYHA classes III or IV stages of heart failure. Cox regression model with time-varying coefficients is applied to deal with these data, which is updated in 2015. Kaplan Meier curves are plotted to screen out categorical variables that violates PH assumptions. As for continuous variables violating PH assumption, Schoenfeld residual plot is drawn to realize time stratification. Therefore, for each time period, cox proportional hazard model can be fit to estimate mortality and find out the key factors promoting or inhibiting death event of heart failure. As a result, age, blood pressure, serum creatinine, and ejection fraction are the significant features of hazard of death led by heart failure, which is validated by Wald test, Likelihood ratio test, and Log-rank test. Discrimination ability is also characterized by ROC curves and AUC finally.

A new right-heart failure staging system in patients with severe tricuspid regurgitation. Prognostic implications

Abstract Objective Our aim was to describe a new right-heart failure (RHF) staging system in patients with severe tricuspid regurgitation (TR). Methods Multicenter, observational, and prospective registry in which all patients with severe TR have been consecutively collected within a 6-month period, classified according to their clinical condition and right ventricular status, and followed up for one year. Results A total of 1247 patients with severe TR [mean age: 76.7±10.5 years, 876 women (70.2%)] were included: 810 (64.9%) met criteria for severe TR, 301 (24.1%) massive TR, and 136 (11%) torrential TR. A new RHF staging was proposed depending on clinical condition, RV dilation and RV systolic dysfunction (Table). The largest group of patients had a normal right ventricle with signs/symptoms of RHF (41%). Death due to refractory HF occurred in 9,2% of patients, hospitalization for HF in 20,8%, and 12,3% underwent TR interventions. In the multivariate analysis the predictors of CV mortality were age, impaired renal function, previous HF admission, massive and torrential TR and Stages III and IV of the new right-heart failure staging system (figure). Conclusion The new RHF staging system accurately stratifies patients with severe TR into prognostic categories.

Prevalence and outcomes of American Heart Association stages of heart failure in an adult brazilian population of the ELSA-Brasil study

Abstract Aims Heart failure (HF) has a major impact on public health, affecting up to 2% of adult population. HF staging is helpful in capturing pre-clinical disease and its progression to advanced stages. We aimed to determine the prevalence and mortality of HF stages in the participants of a Brazilian adult cohort. Methods The ELSA-Brasil cohort comprises 15,105 adult public servants from 6 Brazilian capitals. In the initial evaluation of the study (2008-2010), ELSA carried out interviews and clinical, laboratory, and cardiovascular ancillary tests. In this analysis, we included participants who had electrocardiogram and echocardiogram performed at baseline visit, and additional information regarding risk factors and functional capacity. The HF stages were defined based on AHA guidelines criteria as follow: Stage 0 was defined as a healthy individual with no risk factors for heart failure. Stage A (at risk for HF) included those without cardiac structural or functional abnormality but with any of the following conditions: systemic hypertension; diabetes mellitus, obesity, history of myocardial revascularization, history of rheumatic fever, and seropositivity for Chagas’ disease. Stage B (pre-HF) was defined as asymptomatic participants with history of myocardial infarction or any major abnormalities on ECG or echocardiogram. Stage C (symptomatic HF) included participants with a clinical history of HF, or HF symptoms in the presence of structural heart disease (defined as in Pre-HF stage). Considering the community-dwelling profile of the sample, we did not expect to have advanced heart failure patients in our sample. Results We included the 3,267 participants (61±9 years; 53% women) with baseline data. Prevalences of HF stages were stage 0: 938 (29%) A: 1,385 (42%), B: 651 (28%) and C: 293 (9%), with different distribution between sexes (p<0.001). Older participants had higher prevalences of stages B and C (p<0.001), with the prevalence of stage C increasing from 1.8% at 35-44 years to 12.2% at 65-74 years. After 12 years of follow-up, total mortality rates of HF stages were Stage 0: 4%; A:10%. B: 16%, and C: 26%, and respective Cox proportional hazard ratios [95% CI] adjusted for age and sex were A: 1.94 [1.3-2.8], B:2.78 [1.9-4.1], and C: 5.39 [3.6-8.1] compared to stage 0. Conclusions The prevalence of HF in Brazilians reflects what is described in international literature, with a large proportion of individuals in pre-symptomatic stages. A notable shift in the sample toward pre-symptomatic and symptomatic HF occurred gradually and persistently across the age span studied. Mortality rates increase incrementally across the HF stages. This information is important for understanding and planning health policies for this syndrome.

Non-linear causal effects of kidney function on the risk of heart failure: a Mendelian randomization study

Abstract Background Kidney insufficiency is defined as the early stage of heart failure, but Mendelian randomization (MR) analyses based on several large heart failure cohorts suggest no linear causal effect between kidney function and heart failure (HF), inconsistent with observational studies evidence. However, whether there is a non-linear causal relationship between kidney function and HF has not been reported. Methods and Results Observational and non-linear MR analyses were performed using individual-level data from a UK Biobank cohort of white British ancestry subjects (N = 386,304). There were non-linear observational associations of between kidney function as assessed with estimated glomerular filtration rate (eGFR) and HF (P for nonlinear <0.001). Non-linear MR analyses showed a U-shaped association between genetically predicted eGFR values (both creatinine- and cystatin C-based eGFR) and the risk of HF (Quadratic P value < 0.05) and the risk of HF increased with both reduced and supranormal eGFR levels (β1 = -1.70E-05, P1-value = 0.004; β2 = 3.56E-06, P2-value = 0.004). Conclusion This study observed a non-linear U-shaped genetic relationship between eGFR and HF outcomes, indicating that both reduced and supranormal eGFR may be causally linked to a higher risk of HF.Central Illustration

Unveiling the clinical profiles of heart failure across diverse stages and phenotypes: insights from the national echocardiographic society registry

Abstract Background The modern comprehension of heart failure (HF), based on a staging paradigm, demands systematic screening to promptly identify individuals at risk, those in the pre-HF stage, and symptomatic HF patients across various phenotypes (HFpEF, HFmrEF, and HFrEF). The discernment of clinical profiles within these categories holds significant potential for improving screening and ensuring timely therapeutic interventions. Material and Methods Our national echocardiographic society executed a multicenter HF screening program. General practitioners in 13 primary care centers utilized the original mobile app to determine referrals for transthoracic echocardiography and N-terminal pro-B-type natriuretic peptide (NT-proBNP) testing in patients without a prior HF diagnosis. The 2021 ESC guidelines' algorithms were employed for HF diagnosis (HFpEF, HFmrEF, HFrEF). This study identifies two pre-heart failure (pre-HF) stages: "heart stress" (elevated NT-proBNP in asymptomatic individuals with risk factors, regardless of structural heart disease or cardiac dysfunction) and individuals "at risk for HF" (normal NTproBNP and at least one HF risk factor). Ultimately, all patients were categorized into six groups: (I) no HF, no risk; (II) at risk for HF; (III) heart stress; (IV) HFpEF; (V) HFmrEF; and (VI) HFrEF. Subsequently, the eleven clinical variables were compared among groups (II) to (VI) using chi-square test. Results Among 930 screened outpatients (mean age 66±11 years, 61% female), diagnosis of HF was established in 34.2% (Figure, pie). Heart stress was found in 22.3% patients, and 38.1% were at risk for HF, while 5.5 % had neither HF nor risk factors. Group comparison revealed that older individuals were more frequent in the HFpEF group, females predominated in the heart-stress and HFpEF groups, and males in the HFrEF group (Figure, table). Obesity was the most frequent among those at risk and HFmrEF. Atrial fibrillation and pathological ECG increased gradually from those at risk to HFrEF. Previous MI was the most common in heart stress and HFmrEF groups, while arterial hypertension >10 years prevailed in HFpEF and HFmrEF patients. Diabetes mellitus > 5 years was present in 24-28% across groups. CKD or eGFR≤60 ml/min/1.73m² increased gradually towards HFmrEF. The family history of CMP or SCD was positive in 17-24%, with no significant differences observed across groups. Additionally, a small number of patients had a history of previous cardiotoxic cancer treatment, and no significant differences were found between groups. Conclusions The mobile phone application used in primary care successfully identified a significant number of pre-heart failure patients requiring further evaluation. Different HF stages and phenotypes exhibit distinct clinical profiles, aiding in the screening process and contributing to a deeper understanding of the heart's pathophysiological adaptation to diverse risk factors during HF development.

A comparative analysis of conventional echocardiographic findings among different heart failure stages and phenotypes: insights from the national echocardiographic society registry

Abstract Background The contemporary conceptualization of heart failure (HF) encompasses four developmental stages (at risk for HF, pre-HF, symptomatic HF, and advanced HF) and three distinct HF phenotypes categorized by left ventricular ejection fraction (LVEF) (HFpEF, HFmrEF, HFrEF). However, there is a need for a more comprehensive understanding of echocardiographic similarities and differences among pre-HF stages and various HF phenotypes. Material and Methods Our national echocardiographic society conducted a multicenter HF screening initiative. General practitioners in 13 primary care centers utilized the original mobile phone app to determine referrals for transthoracic echocardiography and N-terminal pro-B-type natriuretic peptide (NT-proBNP) testing in individuals without a prior HF diagnosis. The 2021 ESC guidelines' algorithms were used to diagnose HF phenotypes and 2016 EACVI/ASA recommendation² to assess diastolic function. This study defined "heart stress" (elevated NT-proBNP in asymptomatic individuals with risk factors, regardless of structural heart disease or cardiac dysfunction) and "patients at risk for HF" (normal NTproBNP and at least one HF risk factor). All patients were categorized into six groups: (I) no HF, no risk, (II) at risk for HF, (III) heart stress, (IV) HFpEF, (V) HFmrEF, and (VI) HFrEF. Echocardiographic findings were compared among groups (II) to (VI), using ANOVA, Kruskal-Wallis and Chi-squared test, when needed. Results In a cohort of 930 outpatients (mean age 66±11 years, 61% female), 34.2% were diagnosed with HF, 22.3% experienced heart stress, 37.8% were at risk for HF, and 12.8% had neither HF nor risk factors (Figure). While NT pro BNP showed progressive increase, LVEF showed a progressive decline across the groups, reaching its lowest in HFrEF patients (Table). Simultaneously, left ventricular mass index (LVMi), left atrial volume index (LAVi), and maximal velocity of tricuspid regurgitation (TR Vmax) significantly increased in a stepwise manner. Variations in predominant LV geometry were significant across groups (p<0.001): normal LV geometry in those without HF (60.8%), concentric LV remodeling in at-risk patients (38.6%), normal LV geometry in heart stress (49%), concentric LV hypertrophy (LVH) in HFpEF (27.7%), eccentric LVH in HFmrEF (42.3%), and both concentric and eccentric LVH in HFrEF (43.3% each). Diastolic dysfunction increased prevalence across the groups (12.9% vs 24.7% vs 37.6% vs 19.6% vs 51.1%, p<0.001). Remarkably, HFmrEF group had the highest proportion of undetermined diastolic function (14.7% vs 23.1% vs 27.9% vs 50% vs 26.7%, p<0.001). Conclusions The mobile phone app used in primary care setting allowed identification of significant number of individuals in the pre-HF stages, warranting further investigation. Distinct echocardiographic differences in pre-HF stages and HF phenotypes provide valuable insights for early detection and tailored treatments.

Study on the characteristics of acoustic-thermal precursors of destabilization damage in coal-rock combination bodies with different proportions

The instability and failure processes of coal-rock combinations are accompanied by the release of acoustic emission (AE) and infrared radiation (IR) signals. To investigate the characteristics of AE and IR signals during the failure process in coal-rock combinations with different ratios, and to analyze the effectiveness and applicability of the monitoring methods for these two signals in various specimen ratios. In this paper, the uniaxial compression tests were conducted on seven coal-rock combinations with different ratios by using the rock mechanics loading system and the cooperative monitoring platform of infrared and acoustic emission. The results show that (1) the AE counts for failure precursors in coal-rock combinations are positively correlated with the coal-rock ratio, whereas the AE peak counts are negatively correlated. Moreover, as the coal-rock ratio decreases, the slope of the cumulative AE count curve during the peak failure stage approaches 1. (2) During the elastic and yield stages, the maximum infrared radiation temperature (MIRT) curve fluctuates, and just before peak failure, the curve displays a distinctive “V” shape. This “V” shape becomes more pronounced as the coal-rock ratio decreases. (3) In the monitoring of damage precursors of coal-rock combinations, when the ratio of coal to rock is 1:3 or less, IR monitoring is better than AE monitoring. Conversely, when the ratio of coal to rock is greater than 1:3, AE monitoring is more suitable. Consequently, the combined monitoring of AE and IR signals can increase the reliability and precision of early warning signals for coal-rock assemblage damage precursors.

Mechanical behaviour of rigid-flexible combined structures: Aluminium-inflated membrane beams for application in floating photovoltaic platform

This study aims to investigate the bending and failure behaviour of aluminium-inflated membrane beams for their applications in floating photovoltaic platforms. Four-point bending tests are conducted for a range of inflated pressures and two different deck heights to assess their effect on structural stiffness and ultimate bearing capacity. Meanwhile, the surface-based fluid cavity method is employed to develop the finite element model with the material properties determined by independent coupon-level tests. The bearing capacity of the aluminium-inflated membrane beam is positively correlated with the internal pressure and deck height. The midspan strain distribution is similar to those of the traditional four-point bending beam with the upper part undergoing compression and the lower part experiencing tension, however, the structural behaviour at the failure stage is different. Failure typically occurs due to localised depressions at the loading points on the aluminium deck, ultimately leading to structural failure. The numerical model closely matches the experimental data for the initial inflated and bending configurations, exhibiting a deviation of only 0.10 % to 0.46 % in diameter and 0.32 % to 5.57 % in equivalent bending stiffness. A parametric study shows that the loading properties of the beam are more sensitive to the internal pressure than the deck height and thickness.

Ductility and cracking behavior of UHPC-RC composite beam under bending test based on acoustic emission parameters

Ultrahigh-performance concrete (UHPC) possesses improved mechanical properties due to its high strength, durability, and toughness. Currently, there is a single method for detecting the cracking behavior and evaluating the ductility of the UHPC-reinforced concrete (RC) composite beam. As an important part of structural non-destructive monitoring techniques, the acoustic emission (AE) technique can be used to analyze the damage pattern of the structure by the variation characteristics of its individual parameters. On this basis, four-point bending tests were carried out on the RC beam and UHPC-RC composite beam, and the AE technique was used for ductility analysis and cracking behavior monitoring. The results showed that the UHPC material enhanced the flexural capacity of the UHPC-RC composite beam. The AE ring counts and energy parameters could be used to analyze the cracking process of the UHPC-RC composite beam during flexural damage. The proposed new ductility indices, AE ring counts ductility index (ARD) and AE energy ductility index (AED), differed from the displacement ductility indices within the range of 2 %, providing a new method for calculating ductility indices of concrete structures. During the failure stage, the UHPC-RC composite beam produced more tensile cracks at the early stage of cracking and the stage of damage compared to the RC beam. In addition, the b value of the RC beam had a large range of fluctuations during the failure stage, indicating that the RC beam produced more micro-cracks and macro-cracks and more damage compared to the UHPC-RC composite beam.

Mechanical behaviour of double lining with outer segmental lining and inner fibre reinforced concrete lining under internal water pressure

Double lining with outer segmental lining and inner reinforced concrete lining is extensively used for water conveyance tunnel with internal water pressure. In order to improve the performance of the double lining, the steel rebar and fibre reinforced concrete (R/FRC) is designed for inner lining to enhance the tensile strength of reinforced concrete (RC). Full-scale tests were conducted to compare the mechanical behaviour of double lining with inner RC and R/FRC linings. The test results showed that both types of lining failed in four stages: elastic stage, inner lining cracking stage, crack stabilization and segmental joint damage stage, and failure stage. The cracks firstly occurred in the inner lining near the segmental joints and then propagated to the whole inner lining ring. Finally, the crack width and segmental joint opening successively exceeded the thresholds, and the double lining failed until the breaking of segmental joints. Compared with inner RC lining, R/FRC lining had better performance in terms of the initial cracking load, cracking-control ability, post-cracking stiffness, service limit capacity of inner lining and waterproof capacity of segmental lining. The improvement ratios were 36.3%, 50.3%, 46.3%, 37.2% and 31.1%, respectively. The influences of fibre volume fraction, fibre aspect ratio, and reinforcement ratio of steel rebar on the mechanical performance of R/FRC lining were also investigated based on a previously proposed analytical model. The parametric analysis demonstrated that higher fibre volume fraction and fibre aspect ratio can result in more significant increase of mechanical performance of R/FRC lining. The steel fibres were found to have more significant effects on the post-cracking behaviour of the lining than same amounts of reinforcing bars. Finally, an optimized function was proposed to fulfil a balance of lining performance and economy. The experimental and analytical results indicated that R/FRC lining can substitute RC lining and perform higher mechanical performance in water conveyance tunnels.

Prevalence of High Activated Partial Thromboplastin Time (aPTT) among Patients with Liver Cirrhosis Department of Medicine at Saidu Group of Teaching Hospital, Swat

Introduction: Chronic liver disease or liver cirrhosis is a disease condition in which fibrosis and the creasing of the liver are not functioning correctly. The severity of cirrhosis depends upon the extent of liver failure. Advanced stages of liver failure that create an abnormal coagulation profile have increased the tendency towards bleeding and have consequently increased the hospitalization rates and mortality among cirrhotic patients. Activated partial thromboplastin time is a test that measures activity of Factors VII, IX, XI, and XII. An increased aPTT is due to decreased synthesis of measuring clotting factors in the sample indirectly decreases synthesis from the liver. Department of Medicine, Saidu Group of Teaching Hospital Swat Duration of study: From 13 August 2020 to 14 Feb 2021. Total 195 cases of cirrhosis are consecutively selected from OPD and activated partial thromboplastin time (aPTT). Results: The mean age of sample was 45.2 + 7.3 years. 68.2% was male gender while 31.8% is female gender. The mean duration of the disease was 7.1 + 2.5 years. The results showed acute decompensation in 34.9% and 30.8% had hospitalization history due to decompensation. Cardiac drug use history was present in 34.9%. The results further showed that 45.1% patients were diagnosed with prolonged aPTT. Conclusion: Prolongation of aPTT is a frequent problem in our local cirrhotic population. Further studies are needed to develop an association of factors that lead to the prolongation of aPTT, its control, and its effect on morbidity and mortality of patients with cirrhosis. Keywords. Liver cirrhosis, coagulation disorders, activated partial thromboplastin time, acute decompensation

Targeting MuRF1 to Combat Skeletal Muscle Wasting in Cardiac Cachexia: Mechanisms and Therapeutic Prospects.

Cardiac cachexia, the terminal stage of chronic heart failure, is characterized by severe systemic metabolic imbalances and significant weight loss, primarily resulting from skeletal muscle mass depletion. Despite the detrimental consequences, there is no standardized and clinically-approved intervention currently available for cardiac cachexia. In the context of cardiac cachexia, accelerated protein turnover, that is, inhibited protein synthesis and enhanced protein degradation, plays a crucial role in skeletal muscle wasting. This process is primarily mediated by various proteins encoded by atrogenes. Among them, the atrogene Trim63 (tripartite motif family 63) and its encoded protein MuRF1 have been extensively studied. This review article aims to elucidate the pathogenic mechanisms underlying skeletal muscle wasting in cardiac cachexia, describe the biochemical characteristics of MuRF1, and provide an overview of the investigation into MuRF1-targeting inhibitors. The ultimate goal is to offer novel strategies for the clinical treatment for skeletal muscle wasting associated with cardiac cachexia.

Strain-softening model for granite and sandstone based on experimental and discrete element methods

Combing macroscopic experimental method and mesoscopic numerical method, this study analyses the strain-softening behaviours of granite and sandstone. From the macroscopic perspective, the stress–strain curves of granite and sandstone under different confining pressures are studied by laboratory triaxial compression test. Variations of post-peak reduction modulus and critical plastic shear strain versus confining stress are obtained. Evolution of strength parameters at peak, residual and strain-softening stage are proposed. Then a method to develop the strain-softening model of hard and soft rocks is presented. From the mesoscopic perspective, based on the laboratory test results, the parameters of discrete element method PFC for the samples of the granite and sandstone are calibrated. Comparing the basically consistent results of laboratory experiment and numerical simulation, the feasibility of discrete element method is verified. Evolutions of mesoscopic crack propagation and mesoscopic particle displacement field in the complete failure process are analysed. Typical stresses of granite sample and sandstone sample in the failure stage are investigated. Above combined macroscopic experimental method and mesoscopic numerical method systematically analyse the characteristics of hard rock and soft rock in the strain-softening stage. Failure process and mechanical property of hard rock and soft rock are revealed at the macroscopic and mesoscopic levels. The initiation and propagation process of micro-cracks in rock are thoroughly investigated. The research results provide a scientific foundation for the analyse of strain-softening behaviour of hard rock and soft rock. The result shows that both the mesoscopic numerical method and macroscopic experimental method indicate that the failure pattern of sandstone is influenced by both confining pressure and axial stress, while granite is mainly affected by axial stress.