Initial Investigation Research Articles

Increasing accuracy in predicting mode I fracture toughness of rock structures: a comparative analysis of the rock engineering system method

The investigation of crack initiation and expansion is vital for the stability of structures. The Mode I fracture toughness (KIc) of rocks is a key property used to predict crack propagation in tension and hydraulic fracturing. Various methods have been introduced to determine KIc, but results differ due to factors like sample dimensions, crack geometry, groove type, and loading conditions. The cracked chevron notched Brazilian disc (CCNBD) sample is commonly used in laboratory tests for its easy preparation. This study employs the rock engineering system (RES) technique to overcome the challenges of time-consuming and costly laboratory tests and the uncertainty in traditional methods (analytical, numerical, experimental, laboratory, regression). Using 88 CCNBD rock samples proposed by ISRM, input parameters include thickness of the disc specimen (B), uniaxial tensile strength (σt), initial crack length (α0), radius of the disc specimen (R), crack length (αB), and the length of the final crack (α1). The RES-based model used 70 data points (80% of the dataset) for development, and 18 data points (20%) for evaluation. Regression analysis compared the performance of the RES method, using statistical indicators such as squared correlation coefficient (R2), mean square error (MSE), and root mean square error (RMSE) to measure accuracy. The RES-based method outperformed other regression techniques, demonstrating significantly enhanced accuracy. This highlights the effectiveness and superior performance of the RES method in estimating fracture toughness, particularly for CCNBD samples, showcasing its potential as a robust analytical tool.

In-situ experimental characterization and numerical investigation of the crack initiation of SMC composite under uniaxial tension

This paper explored the crack initiation of sheet molding compound (SMC) composite under uniaxial tensile loads by integrating in-situ experimental characterization and subsequent numerical analysis. Firstly, a synchrotron micro-X-ray computed tomography was utilized to character the morphology and evolution of the microstructure and fracture features of the SMC sample with different loading conditions. Meanwhile, the digital volume correlation technology was employed to determine the internal three-dimensional deformation. Then, a numerical analysis was conducted to describe the relationships among the microstructure, deformation distribution, and position of the crack initiation. Finally, a predictive model was developed based on the internal microstructure and the deformation distribution and then utilized to predict the location and sequence of crack initiation. The good agreement between the predicted results with the experimental ones reveals the feasibility of the proposed model in exploring the fracture behaviors of carbon fiber reinforced polymer composites with complex internal microstructure.

Modeling X chromosome inactivation using t5iLA naive human pluripotent stem cells

BackgroundX chromosome inactivation (XCI) is a critical epigenetic event for dosage compensation of X-linked genes in female mammals, ensuring developmental stability. A robust in vitro model is required for mimicking XCI during the early stages of embryonic development. This methodology article introduces an advanced framework for the in-depth study of XCI using human pluripotent stem cells (hPSCs). By focusing on the transition between naive and primed pluripotent states, we highlight the role of long non-coding RNA X-inactive specific transcript (XIST) and epigenetic alterations in mediating XCI.ResultsOur methodology enables the distinction between naive and primed hESCs based on XIST expression and the activity of X-linked reporters, facilitating the investigation of XCI initiation and maintenance. Through detailed experimental procedures, we demonstrate the utility of our hESC lines in modeling the process of human XCI, including the establishment of conditions for random XCI induction and the analysis of X chromosome reactivation.MethodsThe study outlines a comprehensive approach for characterizing the X chromosome status in hPSCs, employing dual fluorescent reporter hESC lines. These reporter lines enable real-time tracking of XCI dynamics through differentiation processes. We detailed protocols for the induction of X chromosome reactivation and inactivation, as well as the X status characterization methods including cultivation of hESCs, flow cytometric analysis, RNA fluorescence in situ hybridization (FISH), and transcriptome sequencing, providing a step-by-step guide for researchers to investigate XCI mechanisms in vitro.ConclusionsThis article provides a detailed, reproducible methodology for studying XCI mechanisms in vitro, employing hPSCs as a model system. It presents a significant advance in our ability to investigate XCI, offering potential applications in developmental biology, disease modeling, and regenerative medicine. By facilitating the study of XCI dynamics, this methodological framework paves the way for deeper understanding and manipulation of this fundamental biological process.

Temporal structures that determine consistency and quality of care: a case study in hyperacute stroke services

BackgroundTemporal structuring is determined by practices and social norms and affects the quality and timing of care. In this case study of hyperacute stroke wards which provide initial stroke investigation,...

Atomic scale investigation of interfacial damage initiation in SnPb alloy: structural stability and defect-interface interactions

Atomic scale investigation of interfacial damage initiation in SnPb alloy: structural stability and defect-interface interactions

Relugolix prescribing practices and clinical experiences at an urban academic center.

e17008 Background: Relugolix is a novel oral GnRH antagonist that is now an alternative option for patients with prostate cancer (PC) who require androgen deprivation therapy (ADT). The potential benefits of relugolix include rapid testosterone decline and recovery, oral administration, and a possible cardiovascular (CV) benefit compared to traditional GnRH agonists. This study examines real-world data on relugolix prescribing practices and clinical experiences at a large, urban academic center. Methods: We conducted a retrospective, single-center cohort study of patients with PC prescribed relugolix from March 2021 through December 2023 at Beth Israel Deaconess Medical Center. We collected patient-related and clinical factors including demographics, comorbidities, CV risk factors, treatment history, reasons for relugolix prescription over GnRH agonists, medication compliance, adverse effects, and treatment outcomes. Descriptive statistics were used to characterize the cohort. Results: Among 267 patients who received a relugolix prescription, median age was 70 years old, 186 patients (69.6%) were Non-Hispanic White, 37 (13.9%) Non-Hispanic Black, 13 (4.9%) Asian, and 6 (2.2%) Hispanic of any race. Across all patients, 228 (85.3%) initiated relugolix with a median therapy duration of 181 days (range: 10 - 807). At the time of prescription, 88 patients (32.9%) were prescribed concurrent androgen receptor signal inhibitors (ARSI) and 186 (69.6%) had localized disease. Median CV risk factors per patient was 2 (range 0 - 7), and 4 patients (1.5%) developed major adverse CV events (MACE), including acute heart failure decompensation, sick sinus syndrome, ventricular tachycardia, and death during treatment. Among physician prescribers, the most common reasons for prescribing relugolix included concern for CV risk (90 prescriptions, 33.3%) and patient preference for oral administration (55 prescriptions, 20.4%). Forty-nine patients (18.3%) were switched from a GnRH agonist, mainly due to physician concern for CV risk (13, 4.9%) or patient preference (17, 6.4%). Conclusions: We describe real-world use of relugolix for PC in a large, diverse single center cohort. The most frequent reasons for choosing relugolix over a GnRH agonist were physician concern for CV risk and patient preference for a tablet over injection. Investigations of treatment initiation and adherence in relation to insurance coverage, adverse effects, and socioeconomic factors require further investigation.

Failure investigation of fatigue crack initiation and propagation in compressor blade

Blades are integral components of gas turbines and are subjected to critical conditions, bearing radial forces resulting from rotation. Additionally, they directly interact with high-pressure air. This research investigates the failure of GE-Frame9 compressor blades through experimental analyses. Chemical analysis, metallography, and fractography were performed on the fractured blades. The causes of failure in the first-row blades included rubbing with the casing and bending in the opposite direction of rotor rotation. Furthermore, four rows of compressor blades were extensively damaged, with some breaking at the root area. During the turbine overhaul, a shim plate was placed between the compressor blades' root and disk. Metallography confirmed that placing the shim at the blade-disc connection point resulted in stress concentration at blades root. Fractography of the fractured blade surface indicated signs of fatigue failure, and a correlation was found between the crack initiation site and the impact of the shim plates on the blade root. Fatigue crack initiation occurred due to stress concentration caused by the shim's edge, propagating through the blade root during turbine operation and ultimately leading to complete fracture. These results emphasize the importance of avoiding the placement of shims on inclined surfaces of blade roots and ensuring full contact between the surfaces to prevent stress concentration and subsequent failure.

Investigation of the New Generation University Initiative: The Case of Atatürk University

Investigation of the New Generation University Initiative: The Case of Atatürk University

Micro-mechanics investigation of heterogeneous deformation fields and crack initiation driven by the local stored energy density in austenitic stainless steel welded joints

This work investigates the heterogeneous deformation and failure of HR3C austenitic stainless steel welded joints at room and typical service temperatures. Such types of welded joints are widely used in the new generation of fossil fuel power stations and are known to suffer from premature high temperature failure. Observation of in-service failures revealed that cracks may nucleate either in the heat affected zone or in the weld metal. The main objective of this work is to identify the local microstructural conditions and stress–strain fields responsible for both ductile failure and micro-crack nucleation within the weldment at low and high temperatures, respectively. To that purpose, a novel multi-scale micromechanics-based modelling framework is proposed. It relies on representative weld microstructure models digitally reconstructed from electron backscatter diffraction measurements, and dislocation density-based crystal plasticity models to describe the behaviour of individual grains in each weld region. A novel thermo-dynamically consistent relation for the configuration stored energy per unit volume is derived from the crystal plasticity framework.The single crystal models are calibrated and validated from a combination of uniaxial tensile tests on cross-weld specimens using high resolution digital image correlation techniques, representative volume elements of the polycrystals at the macro-scale, as well as micropillar compression tests at the scale of the individual grains. Predictions of heterogeneous inelastic deformation fields within the weldment at both 22 °C and 665 °C, and of micropillar compression behaviour of the individual weld single crystal phases are consistent with experimental data. The experimentally observed ductile failure of the weld metal at room temperature is successfully predicted using a Gurson-type void nucleation, growth and coalescence constitutive model. The suitability of the stored strain energy density and the accumulated plastic strain as crack initiation/creep failure indicators is investigated. It was found that predicted creep lifetimes with either indicator were very similar, and that they were relatively accurate for low stress levels.

Current safeguards, risk mitigation, and transparency measures of large language models against the generation of health disinformation: repeated cross sectional analysis

ObjectivesTo evaluate the effectiveness of safeguards to prevent large language models (LLMs) from being misused to generate health disinformation, and to evaluate the transparency of artificial intelligence (AI) developers regarding...

Citizens’ e-participation in the digital world: empirical insights from Europe

IMPACT This study investigates citizens’ e-participation, examining a large sample of European countries from 2017–2021. Empirical results suggest that the investigation of e-government initiatives cannot be limited to technocracy, requiring the consideration of different factors and the various features of citizens’ engagement. Policy-makers and local government leaders planning e-government strategies should know that e-maturity is highly dependent on the characteristics of the context in which a public sector entity operates: meaning that norms, rules and societal values depicting the institutional context matter. They should also go beyond the efficiency dimension of public service delivery and focus on effectiveness.

P136: Artificial Intelligence (AI) and its role in the diagnosis of surgical disease: panacea or potentially dangerous?

Abstract Background AI algorithms are used in many healthcare settings, though concerns about underlying bias and accuracy exist. This study assessed accuracy of AI in investigation and diagnosis of acute surgical patients, when compared with clinicians’ performance. Methods Consecutive patients who attended a surgical SDEC unit over a two-week period in October 2023 were identified. The documented clerking history was inputted into ChatGPT (v3.5) and the algorithm was asked to give the most likely diagnosis and a list of recommended investigations. Clinical records were compared to the AI recommendations. Primary outcome measures were the investigative and diagnostic accuracy of the AI. Results 88 patients were identified. The most common presenting complaints were abdominal pain (57 patients, 64.8%), abdominal swelling (10 patients, 11.4%) or abscess (8 patients, 9.1%). AI correctly diagnosed 32 patients (36%). AI accuracy was greatest for patients with an abscess (6 patients, 75%), and less accurate for abdominal masses (4 patients, 40%) and abdominal pain (12 patients, 21%). AI recommended fewer investigations that doctors (6 versus 7 tests, median). AI recommended fewer blood tests (3 versus 5 tests, median) yet was more likely to recommend cross-sectional imaging and microbiological investigations. Conclusions At present, ChatGPT lacks sufficient diagnostic and investigative maturity to confidently replace a formal surgical clerking and misdiagnosed almost 80% of patients with abdominal pain as well as under-investigating most acute general surgical patients. Development of a bespoke machine-learning algorithm may improve accuracy and enhance the role of AI in triage and initial investigation.

Study of Fatigue Crack Initiation and the Propagation Mechanism Induced by Pores in a Powder Metallurgy Nickel-Based FGH96 Superalloy.

Thermally induced pores (TIPs) are generally the source of fatigue crack initiation in the powder metallurgy (PM) Ni-based FGH96 superalloy. The effect of TIPs on fatigue crack initiation on the surface of the FGH96 superalloy was detected using scanning electron microscopy (SEM). The cause of fatigue crack deflection was studied using electron backscatter diffraction (EBSD) analysis. The results indicated that there are two states of TIPs including isolated TIPs and clustered TIPs located at the grain boundary. The investigation of crack initiation and propagation around TIPs was conducted in detail through the comprehensive integration of experimental findings and computational results. For cracks initiated by isolated TIPs, the maximum equivalent size and the ratio of the vertical-parallel axis to the loading direction of the TIPs reveal a linear relationship, and both of them determine crack initiation. Regarding clustered TIPs, the constituent pores of the clustered TIPs will compete to initiate cracks based on the experimental results, and the largest pore will be more likely to initiate cracking. Moreover, the results showed that fatigue crack propagation can be hindered by hard-orientation grains and twins with a low Schmid factor (SF). Large-angle crack deflection due to twins with a low SF can significantly increase crack length and resistance to crack propagation.

"Breaking down in tears, soaked in sweat, and sick from the heat": Media-based composite narratives of first responders working during the 2021 Heat Dome.

During the summer of 2021, a deadly, unprecedented multiday Heat Dome engulfed western Canada. As a result of this extreme heat event (EHE), emergency dispatchers received an unparalleled increase in incoming 911 calls for ambulance, police, and fire (as first responders) services to attend to hundreds of heat-vulnerable community members succumbing to the heat. With 103 all-time heat records broken during this EHE and indoor temperatures of nearly 40°C, the first responders attending these calls faced extensive job demands and highly challenging operating conditions. Initial investigations have explored the health system-level impacts; however, little has been done to explore the impact on the first responders themselves. Therefore, this study aimed to improve our understanding of EHEs' impacts on the operational capabilities and health of first responders, specifically police, fire, ambulance, and dispatch services. A systematized review and content analysis of media articles published on the 2021 Heat Dome in Canada was conducted (n = 2909), and four media-based composite narratives were developed highlighting police, fire, ambulance, and dispatch services. The Job Demands-Resources (JD-R) model was applied as atheoretical framework for occupational burnout. The media-based composite narratives highlighted that first responders faced record-breaking call volumes, increased mental-health-related claims, and exhaustive heat-related physiological stress. Using the JD-R model as a theoretical framework for occupational burnout, we identified three measures of stressful job demand: work overload (e.g., the surge in call volume, firefighters responding to medical emergencies), emotional demands (e.g., severe medical emergencies, sudden deaths, unresponsive patients, distraught family members), and physical demands (e.g., resuscitation in personal protective equipment, heat-related illness). The experiences described underscore the importance of supporting first responders during work in extreme heat conditions. These findings have important implications for addressing rising rates of burnout during and following public health crises, such as EHEs, a problem that is increasingly being recognized as a threat to the Canadian public healthcare system.

Low-coverage whole genome sequencing of diverse Dioscorea bulbifera accessions for plastome resource development, polymorphic nuclear SSR identification, and phylogenetic analyses.

Dioscorea bulbifera (Dioscoreaceae), a versatile herbaceous climber native to Africa and Asia, holds significant nutritional and medicinal value. Despite extensive characterization and genetic variability analyses of African accessions, studies on the genetic variation of this species in China are limited. To address this gap, we conducted low-coverage whole genome sequencing on D. bulbifera accessions from diverse regions across mainland China and Taiwan island. Our initial investigation encompassed comprehensive comparative plastome analyses of these D. bulbifera accessions, and developing plastome resources (including plastome-derived repetitive sequences, SSRs, and divergent hotspots). We also explored polymorphic nuclear SSRs and elucidated the intraspecific phylogeny of these accessions. Comparative plastome analyses revealed that D. bulbifera plastomes exhibited a conserved quadripartite structure with minimal size variation mainly attributed to intergenic spacer regions, reinforcing prior observations of a high degree of conservation within a species. We identified 46 to 52 dispersed repeats and 151 to 163 plastome-derived SSRs, as well as highlighted eight key divergent hotspots in these D. bulbifera accessions. Furthermore, we developed 2731 high-quality candidate polymorphic nuclear SSRs for D. bulbifera. Intraspecific phylogenetic analysis revealed three distinct clades, where accessions from Southeast China formed a sister group to those from South China and Taiwan island, and collectively, these two clades formed a sister group to the remaining accessions, indicating potential regional genetic divergence. These findings not only contributed to the understanding of the genetic variation of D. bulbifera, but also offered valuable resources for future research, breeding efforts, and utilization of this economically important plant species.

Analysis of personality traits using Myers-Briggs type indicator in correlation to the academic performance of BS ECE undergraduates

academic performance among Bachelor of Science in Electronics Engineering (BS ECE) students. A sample of 70 students completed the Myers-Briggs Type Indicator (MBTI) assessment and provided academic performance data. Statistical analyses using Microsoft Excel examined associations between MBTI types and achievement. Overall, sensing and introverted types like ISTJ and ISFJ were most prevalent while intuitive, extroverted types were uncommon. The highest academic scorers frequently exhibited introverted, sensing, feeling traits such as ISFJ. Lower performers sometimes showed opposite extraverted, thinking types like ESTJ. Results indicate certain personality profiles may be drawn to engineering fields where they can thrive. However, variations emerged even among poorer scorers. Differences in thinking versus feeling dimensions also distinguished top and bottom achievers. While insightful, the small sample size limits generalizability. Assessing more undergraduate year levels could provide additional perspectives. Findings imply tailoring instructional methods to traits like introversion or thinking may optimize student engagement and learning. Monitoring personality development throughout engineering curricula may also support retention. Further research on personality's interaction with program demands over time is needed. Exploring larger samples across multiple cohorts and degrees could reveal more patterns. This initial investigation fills a knowledge gap, but expanded studies using bigger samples will deepen understanding of links between personality and performance in engineering education.

A rare case of infective spondylodiscitis in an 18-month-old infant: Clinical presentation and management

Spondylodiscitis is a rare inflammatory condition predominantly observed in adults and presents unique challenges when encountered in infants. Diagnosis in this population is complicated by non-specific symptoms necessitating a high index of suspicion and comprehensive clinical evaluation. This case study reports an exceptional spondylodiscitis case in an 18-month-old infant presented with prolonged asthenia, refusal to walk, loss of appetite, and fever. Physical examination revealed general well-being, good hydration, and bilateral tonsillar hypertrophy. The pain was noted in the right hip joint and thoracolumbar spine while hip joint mobility was unrestricted. Initial investigations were conducted including blood tests, ultrasound of the right hip, and lumbosacral spine radiography, all within normal limits. Magnetic resonance imaging indicated spondylodiscitis. Empiric antibiotic therapy was administered. The fever subsided, and the patient’s condition improved leading to conservative treatment with a custom-fitted orthosis. After 15 days of hospitalization, the patient was discharged. This case report aimed to underscore the importance of early recognition and appropriate intervention as well as the need for multidisciplinary collaboration in managing pediatric spondylodiscitis.

Evolutionarily conserved roles of foxg1a in the developing subpallium of zebrafish embryos.

The vertebrate telencephalic lobes consist of the pallium (dorsal) and subpallium (ventral). The subpallium gives rise to the basal ganglia, encompassing the pallidum and striatum. The development of this region is believed to depend on Foxg1/Foxg1a functions in both mice and zebrafish. This study aims to elucidate the genetic regulatory network controlled by foxg1a in subpallium development using zebrafish as a model. The expression gradient of foxg1a within the developing telencephalon was examined semi-quantitatively in initial investigations. Utilizing the CRISPR/Cas9 technique, we subsequently established a foxg1a mutant line and observed the resultant phenotypes. Morphological assessment revealed that foxg1a mutants exhibit a thin telencephalon together with a misshapen preoptic area (POA). Notably, accumulation of apoptotic cells was identified in this region. In mutants at 24 h postfertilization, the expression of pallium markers expanded ventrally, while that of subpallium markers was markedly suppressed. Concurrently, the expression of fgf8a, vax2, and six3b was shifted ventrally, causing anomalous expression in regions typical of POA formation in wild-type embryos. Consequently, the foxg1a mutation led to expansion of the pallium and disrupted the subpallium and POA. This highlights a pivotal role of foxg1a in directing the dorsoventral patterning of the telencephalon, particularly in subpallium differentiation, mirroring observations in mice. Additionally, reduced expression of neural progenitor maintenance genes was detected in mutants, suggesting the necessity of foxg1a in preserving neural progenitors. Collectively, these findings underscore evolutionarily conserved functions of foxg1 in the development of the subpallium in vertebrate embryos.

An initial investigation into the use of machine learning methods for prediction of carcass component yields in F2 broiler chickens

Context As evaluation of carcass components is costly and time consuming, models for prediction of broiler carcass components are useful. Aims The aim was to investigate the feasibility of machine learning methods in the prediction of carcass components from measurements on live birds during the rearing period. Methods Three machine learning methods, including regression tree, random forest and gradient-boosting trees, were applied to predict carcass yields, and benchmarked against classical linear regression. Two scenarios were defined for prediction. In the first scenario, carcass yields were predicted by live bodyweight, shank length and shank diameter features, recorded at 2, 3 and 4 weeks of age. In the second scenario, predictor features recorded at 5, 6 and 7 weeks of age were used. The two scenarios were reanalysed by including effective single-nucleotide polymorphisms associated with bodyweight, shank length and shank diameter as new predictor features. Key results The correlation coefficient between predicted and observed values for predicting weight of carcass traits ranged from 0.50 for wing to 0.59 for thigh in the first scenario, and from 0.63 for wing to 0.74 for carcass in the second scenario. These predictions for the percentage of carcass components ranged from 0.30 for wing to 0.39 for carcass and breast in the first scenario, and from 0.34 for thigh to 0.43 for carcass in the second scenario when random forest was used. Conclusions Predictive accuracy in the first scenario was lower than in the second scenario for all prediction methods. Including single-nucleotide polymorphisms as predictor features in either scenario did not increase the accuracy of the prediction. Implications In general, random forest had the best performance among machine learning methods, and classical linear regression in two scenarios, suggesting that it may be considered as an alternative to conventional linear models for prediction of carcass traits in broiler chickens.

Usefulness of fat-containing agents: an initial study on estimating fat content for magnetic resonance imaging.

This initial study aimed at testing whether fat-containing agents can be used for the fat mass estimation methods using magnetic resonance imaging (MRI). As an example for clinical application, fat-containing agents (based on soybean oil, 10% and 20%), 100% soybean oil, and saline as reference substances were placed outside the proximal femurs obtained from 14 participants and analyzed by 0.3T MRI. Fat content was the estimated fat fraction (FF) based on signal intensity (SIeFF, %). The SIeFF values of the femoral bone marrow, including the femoral head, neck, shaft, and trochanter area, were measured. MRI data were compared in terms of bone mineral content (BMC) and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) in the proximal femur. Twelve pig femurs were also used to confirm the correlation between FF by the DIXON method and SIeFF. According to Pearson's correlation coefficient, the SIeFF and total BMC and BMD data revealed strong and moderate negative correlations in the femoral head (r < - 0.74) and other sites (r = - 0.66 to - 0.45). FF and SIeFF showed a strong correlation (r = 0.96). This study was an initial investigation of a method for estimating fat mass with fat-containing agents and showed the potential for use in MRI. SIeFF and FF showed a strong correlation, and SIeFF and BMD and BMC showed correlation; however, further studies are needed to use SIeFF as a substitute for DXA.