Prior Studies Research Articles

Tragedy of the Commons in Crowd Work-Based Research

Academic scholars have leveraged crowd work platforms such as MTurk to conduct research and collect data, but the data quality crisis in crowd work has been an alarming phenomenon recently. Though prior studies have discussed data quality and validity issues in crowd work via surveys and experiments, they kind of neglected to explore the scholars’ and particularly the IRB's ethical concerns and the related policies in various ethical guidelines for crowd work-based research in these respects. In this study, we interviewed 17 scholars from six disciplines and 15 IRB directors and analysts in the U.S. and analyzed 28 research guidance documents to fill these gaps. We identified common themes among our interviewees and documents but also discovered distinctive and even opposing views regarding the approval rate, rejection, and internal/external research validity. Based on the findings, we discussed a potential Tragedy of the Commons regarding data quality deterioration and the disciplinary differences regarding validity in crowd work-based research. We further explored the origin of the data quality and validity issues in crowd work-based research. We advocated the IRB's ethical concerns in crowd work-based research be heard and respected further and be reflected in the ethical guidance for crowd work-based research. Finally, we proposed our research implications, limits, and future work.

Return to Activities of Daily Living After Fusion to the Pelvis for Adult Spinal Deformity

Study Design: Cross-sectional survey and retrospective review of prospectively-collected data. Objective: To investigate return to activities among adult spinal deformity (ASD) patients following long-segment fusion to the pelvis. Summary of Background Data: No prior studies have assessed the extent and timing of return to employment, driving, and walking among a single cohort of ASD patients. Methods: Patients who underwent thoracolumbar ASD surgery between 2016-2021 with ≥1 year follow-up were included (posterior-only, ≥3 levels of fusion to pelvis). A cross-sectional survey was implemented to evaluate preoperative and postoperative activity tolerance. Patients were categorized into (1)Better/Unchanged or (2)Worse groups based on their postoperative activity tolerance to allow for comparison of demographics and perioperative variables. Results: Ninety-five patients were included (mean age:64.3±10.1 years; body mass index (BMI):27.3±6.1 kg/m2; levels fused:8 [range 3-16]; follow-up:43.5 months). Most patients endorsed improved capacity to walk (improved:64.2%, unchanged:17.9%, worse:17.9%) and navigate stairs (improved:52.6%, unchanged:33.7%, worse:13.7%) postoperatively. Seventy-five (97.4%) patients returned to driving (4.1±10.8 months) and 44 (88.0%) patients returned to work (5.4±8.0 months). Patients with decreased walking tolerance were more likely to have greater lumbar lordosis correction (37.2±10.5° vs. 18.6±16.7°, P=0.02) and worse Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF) at long-term follow-up (40.2±11.0 vs. 48.0±9.6, P=0.03). Patients with decreased ability to navigate stairs were more likely to have undergone revision fusion (69.2% vs. 28.0%, P=0.003) and have greater BMI (30.7±5.8 vs. 26.7±6.0 kg/m2, P=0.04). Patients requiring the use of a postoperative assistive walking device were more likely to have undergone revision fusion (66.7% vs. 27.5%, P=0.003), exhibit greater BMI (31.4±7.2 vs. 26.5±5.6 kg/m2, P=0.004), longer operative times (285.1±79.9 vs. 244.5±63.4 minutes, P=0.03), and worse PROMIS-PF at long-term follow-up (39.9±5.1 vs. 47.7±10.5, P=0.04). Conclusion: Despite the reduced range of motion caused by spinopelvic fusion, a majority of patients are able to successfully return to ADLs after deformity surgery.

The Impact of Cruise Controllability on the Decision Making of Schedule Construction

Nowadays, challenged by diverse uncertainties and disruptions (e.g., bad weather), as well as the strict environmental regulations imposed by authorities (e.g., on carbon emissions), airlines are struggling. How to improve their operational efficiency in such a volatile and adverse market becomes a top agenda of airlines. Among various operations, crew scheduling is fundamentally important as staffing cost is a big part of the total operational expenses. It is known that in crew scheduling, “robust crew pairing” is crucial to make the produced pairings less vulnerable in real operations. Existing studies generally construct robustness assuming that the aircraft cruise speed is fixed. However, prior studies have found that flight times exhibit significant variations due to reasons like cruise speed adjustment, and aircraft can control cruise speed for purposes like reducing delays. For crew, cruise speed controllability is also useful in hedging disruptions. For example, one flight can speed up to meet its on-time arrival even if it departs late due to crew disruptions. However, the impacts of cruise speed controllability on crew pairing robustness and the related environmental costs are under-explored. We thus propose this preliminary study to explore the possibility to use cruise speed controllability to enhance schedule robustness for crews.

Differential Cognitive Effects of Unilateral Subthalamic Nucleus Deep Brain Stimulation for Parkinson's Disease.

The aim of this study was to investigate the cognitive effects of unilateral directional versus ring subthalamic nucleus deep brain stimulation (STN DBS) in patients with advanced Parkinson's disease. We examined 31 participants who underwent unilateral STN DBS (left n = 17; right n = 14) as part of an National Institutes of Health (NIH)-sponsored randomized, double-blind, crossover study contrasting directional versus ring stimulation. All participants received unilateral DBS implants in the hemisphere more severely affected by motor parkinsonism. Measures of cognition included verbal fluency, auditory-verbal memory, and response inhibition. We used mixed linear models to contrast the effects of directional versus ring stimulation and implant hemisphere on longitudinal cognitive function. Crossover analyses showed no evidence for group-level changes in cognitive performance related to directional versus ring stimulation. Implant hemisphere, however, impacted cognition in several ways. Left STN participants had lower baseline verbal fluency than patients with right implants (t [20.66 = -2.50, p = 0.02]). Verbal fluency declined after left (p = 0.013) but increased after right STN DBS (p < 0.001), and response inhibition was faster following right STN DBS (p = 0.031). Regardless of hemisphere, delayed recall declined modestly over time versus baseline (p = 0.001), and immediate recall was unchanged. Directional versus ring STN DBS did not differentially affect cognition. Similar to prior bilateral DBS studies, unilateral left stimulation worsened verbal fluency performance. In contrast, unilateral right STN surgery increased performance on verbal fluency and response inhibition tasks. Our findings raise the hypothesis that unilateral right STN DBS in selected patients with predominant right brain motor parkinsonism could mitigate declines in verbal fluency associated with the bilateral intervention. ANN NEUROL 2024;95:1205-1219.

Dirac Geometric Approach for the Unimodular Holst Action

We perform a Hamiltonian analysis of unimodular gravity in its first-order formulation, specifically a modification of the Holst action. In order to simplify the analysis, prior studies on this theory have introduced (for several reasons) additional elements, such as parametrization, complex fields, or considering the Barbero–Immirzi parameter as imaginary. We show that, by using a geometric implementation of the Dirac algorithm, a comprehensive analysis of the theory can be conducted without relying on these additional ingredients. The resulting theory reproduces the behavior of metric unimodular gravity.

Newly Graduated Physical Education Teachers’ Experiences of and Readiness for Professional Practice: A Scoping Review

This scoping review examines previously published research on newly graduated physical education (PE) teachers in an effort to describe the scope and types of the empirical studies, perspectives and understandings concerning this population’s experiences of and readiness for the performative and organisational aspects of professional practice. Following an initial review of 71 studies, a total of 16 published studies were found to be eligible for inclusion in the review. A five-step qualitative content analysis then identified the important features of the data related to the stated aim of the review. Prior studies determined newly graduated PE teachers to be qualified in their field, although their professional practice depends on other people’s participation and cooperation within the school environment. A problem-oriented trend was observed in the research data when newly graduated PE teachers were asked to elaborate on their experiences. Moreover, a knowledge gapwas identified in terms of newly graduated PE teachers and their varied experiences of the inductionphase of their professional practice.

The determinants of corporate anti-corruption disclosures: evidence from construction companies in the Asia-Pacific

Purpose This study aims to investigate the determinants of anti-corruption disclosures by construction firms in Asia-Pacific countries. Design/methodology/approach The sample comprises construction companies from seven Asia-Pacific countries from 2015 to 2019. The authors hand-collected data on anti-corruption disclosures by using content analysis. Findings This study provides empirical evidence that government ownership, country-level accounting competence and high-quality auditors increase companies’ anti-corruption disclosures. Meanwhile, this study finds that uncertainty avoidance does not affect companies’ anti-corruption disclosures. Practical implications This study has a number of implications. First, government and professional accountant organizations need to improve accountants’ knowledge and competence through education, training and continuous professional development. Second, public accounting firms need to ensure the quality of their auditors, particularly in the technical competence in financial and nonfinancial reporting. Finally, universities must improve and update their curriculum regarding nonfinancial reporting issues. Originality/value This study is among the first to examine anti-corruption disclosure practices in the most corrupted settings, i.e. the construction industry in Asia-Pacific countries. It uses the isomorphism perspective to explain the influence of government ownership, country-level accounting competence and high-quality auditors on anti-corruption disclosure transparency. The number of prior studies investigating this association is very limited. Moreover, disclosures of anti-corruption information are complex and sensitive; thus, coercive, normative and mimetic pressures are required to achieve higher transparency and sustainability.

The Lost World: Characterizing and Detecting Undiscovered Test Smells

Test smell refers to poor programming and design practices in testing and widely spreads throughout software projects. Considering test smells have negative impacts on the comprehension and maintenance of test code and even make code-under-test more defect-prone, it thus has great importance in mining, detecting, and refactoring them. Since Deursen et al. introduced the definition of “test smell”, several studies worked on discovering new test smells from test specifications and software practitioners’ experience. Indeed, many bad testing practices are “observed” by software developers during creating test scripts rather than through academic research and are widely discussed in the software engineering community (e.g., Stack Overflow) [ 70 , 94 ]. However, no prior studies explored new bad testing practices from software practitioners’ discussions, formally defined them as new test smell types, and analyzed their characteristics, which plays a bad role for developers in knowing these bad practices and avoiding using them during test code development. Therefore, we pick up those challenges and act by working on systematic methods to explore new test smell types from one of the most mainstream developers’ Q&amp;A platforms, i.e., Stack Overflow. We further investigate the harmfulness of new test smells and analyze possible solutions for eliminating them. We find that some test smells make it hard for developers to fix failed test cases and trace their failing reasons. To exacerbate matters, we have identified two types of test smells that pose a risk to the accuracy of test cases. Next, we develop a detector to detect test smells from software. The detector is composed of six detection methods for different smell types. These detection methods are both wrapped with a set of syntactic rules based on the code patterns extracted from different test smells and developers’ code styles. We manually construct a test smell dataset from seven popular Java projects and evaluate the effectiveness of our detector on it. The experimental results show that our detector achieves high performance in precision, recall, and F1 score. Then, we utilize our detector to detect smells from 919 real-world Java projects to explore whether the six test smells are prevalent in practice. We observe that these test smells are widely spread in 722 out of 919 Java projects, which demonstrates that they are prevalent in real-world projects. Finally, to validate the usefulness of test smells in practice, we submit 56 issue reports to 53 real-world projects with different smells. Our issue reports achieve 76.4% acceptance by conducting sentiment analysis on developers’ replies. These evaluations confirm the effectiveness of our detector and the prevalence and practicality of new test smell types on real-world projects.

A Preliminary Study of Thermosets from Epoxy Resins Made Using Low-Toxicity Furan-Based Diols.

Glycidyl ethers are prepared from a series of furan-based diols and cured with a diamine to form thermosets. The furan diols demonstrate lower toxicity than bisphenol-A in a prior study. The diglycidyl ethers show improved thermal stability compared to the parent diols. Cured thermosets are prepared at elevated temperature using isophorone diamine (IPDA). Glass transition temperatures are in the range of 30-54 °C and depend on the structure of the furan diol. Coatings are prepared on steel substrates and show very high hardness, good adhesion, and a range of flexibility. Properties compare favorably with a control based on a bisphenol-A epoxy resin. The study demonstrates that epoxy resins based on furan diols, which have been shown to have lower toxicity than bisphenol-A, can form thermosets having properties comparable to a standard epoxy resin system; and thus, are viable as replacements for bisphenol-A epoxy resins.

Point prevalence of epilepsy in dementia: A "real-world" estimate.

Several studies have demonstrated a higher frequency of seizures and epilepsy in Alzheimer's disease and other forms of dementia as compared with healthy elderly individuals. However, incidence and prevalence of epilepsy in the general population of dementia are unknown since most previous studies were performed in secondary-tertiary referral centres. In addition, all prior studies but one provided "period" rather than "point" prevalence estimates. We assessed point prevalence estimate of epileptic manifestations requiring antiepileptic medication in patients Alzheimer's disease, vascular dementia, and fronto-temporal dementia from a secondary clinical setting. Point prevalence estimates were 6.4% (95% CI: 1.5 to 11.3) in Alzheimer's disease, 8.9% (95% CI: 1.4 to 16.4), in vascular dementia, and 6% (95% CI: 1.3 to 10.7) in fronto-temporal dementia, rates that were greater than those observed in the healthy elderly population. Regardless of the etiology of dementia, epilepsy was characterized by unprovoked seizures that lacked distinguishing clinical features. These findings support epilepsy as part of the spectrum of dementia. The similar point prevalence of definite epilepsy requiring AED treatment in Alzheimer's disease and non Alzheimer dementias raised the possibility of similar underlying mechanism of epileptogenesis. Although this was not a population-based study, accurate point prevalence data from clinic setting would be important to better define the burden of epilepsy in dementia and the demands on health services to manage the condition.

Association of Depression and Antidepressant Use With Driving Behaviors in Older Adults: A LongROAD Study.

Older adults aged 70 and older who drive have higher crash death rates per mile driven compared to middle aged (35-54years) adults who drive in the US. Prior studies have found that depression and or antidepressant medication use in older adults are associated with an increase in the vehicular crash rate. Using data from the prospective multi-site AAA Longitudinal Research on Aging Drivers Study, this analysis examined the independent and interdependent associations of self-reported depression and antidepressant use with driving behaviors that can increase motor vehicle crash risk such as hard braking, speeding, and night-time driving in adults over age 65. Of the 2951 participants, 6.4% reported having depression and 21.9% were on an antidepressant medication. Correcting for age, race, gender, and education level, participants on an antidepressant had increased hard braking events (1.22 [1.10-1.34]) but self-reported depression alone was not associated with changes in driving behaviors.

How to prevent ruining new product development projects with suppliers? A failure factors’ perspective

To efficiently implement Early Supplier Involvement (ESI) in New Product Development (NPD), literature examined the contribution of its success factors to NPD project performance. However, prior studies overlooked the compromising effects of ESI failure factors that should also be carefully managed to foster project performance. Following an in-depth literature review, we identify 16 failure factors and position them according to the collaboration phases, namely relationship design and day-to-day interactions. Then, based on data collected from a survey with 80 practitioners, we use Necessary Condition Analysis (NCA) to determine the degrees of risk criticality for each factor with respect to different thresholds of NPD project performance in terms of cost, quality, time and innovation. As such, we unveil the failure factors most detrimental to the project success, and provide practitioners with guidance to mitigate the ESI failure factors according to the performance criteria they prioritize the most and the performance levels they target.

Assessing the toxicity of pesticides exposure on hepatic miRNA-target gene alterations in rat liver tissues via molecular and integrated network bioinformatics analysis

The prevalent use of pesticides, including pirimiphos-methyl (PPM) and bifenthrin (BF), poses a serious health risk, particularly to workers who encounter these chemicals daily. Despite the recognized hepatotoxic effects, the specific molecular mechanisms, especially those involving miRNAs in liver damage caused by PPM and BF, are not fully elucidated. Prior studies have not exhaustively analyzed the hepatic miRNA-target gene dynamics following exposure to these pesticides; thus, this research aims to fill that gap through an extensive miRNA analysis to discern their regulation in PPM or BF-induced hepatic toxicity. In this study, male Sprague-Dawley rats were exposed to BF or PPM for 28 days through oral gavage, simulating the chronic exposure faced by humans. We conducted a thorough assessment of the hepatotoxicity induced by PPM and BF, employing multiple evaluation levels, including histological analysis, liver enzyme measurements, and real-time PCR to detect changes in hepatic miRNA-target gene expressions. Additionally, we utilized DIANA-miRPath prediction tools to delineate the functional implications of these hepatic miRNA target genes. Our findings reveal a significant modulation in the expression of rno-miR-155–5p and rno-miR-122–5p, along with their target genes, following PPM and BF treatment. In contrast, rno-miR-21–5p levels remained unaltered. These observations suggest potential utility of these specific hepatic miRNAs as biomarkers for liver injury resulting from pesticide exposure. Subsequent GO enrichment analysis linked target genes to functions like molecular activity, protein binding, and cellular processes. Additionally, KEGG pathway analysis showed these genes, influenced by varied miRNA expressions, play significant roles in metabolic and signaling pathways In conclusion, this study enhances our comprehension of the biological roles of miRNAs in hepatic toxicity induced by PPM and BF. The insights gained here not only shed light on molecular mechanisms but also open avenues for considering these miRNAs as potential diagnostic biomarkers in conditions of pesticide-induced hepatotoxicity, thereby guiding future therapeutic strategies.

Beyond the operating room: built environment design knowledge supportive of resilient surgical services

PurposeSurgical services are settings where resilient performance (RP) is necessary to cope with a wide range of variabilities. Although RP can benefit from a supportive built environment (BE), prior studies have focused on the operating room, giving scant attention to support areas. This study takes a broader perspective, aiming at developing BE design knowledge supportive of RP at the surgical service as a whole.Design/methodology/approachSeven BE design prescriptions developed in a previous work in the context of internal logistics of hospitals, and thus addressing interactions between workspaces, were used as a point of departure. The prescriptions were used as a data analysis framework in a case study of the surgical service of a medium-sized private hospital. The scope of the study included surgical and support areas, in addition to workflows involving patients and family members, staff, equipment, sterile instruments and materials, supplies, and waste. Data collection included document analysis, observations, interviews, and meetings with hospital staff.FindingsResults identified 60 examples of using the prescriptions, 77% of which were related to areas other than the operating rooms. The developed design knowledge is framed as a set of prescriptions, examples, and their association to workflows and areas, indicating where it should be applied.Originality/valueThe design knowledge is new in surgical services and offers guidance to both BE and logistics designers.

Social media-related nightmare — a potential explanation for poor sleep quality and low affective well-being in the social media era?

Research has posited that social media use during the day may be reflected in nighttime dreams. Nevertheless, no prior studies have explored frightening, unpleasant dreams arising from social media use. This study introduces the construct of the social media-related nightmare by (a) developing and validating a scale capturing negative-valenced dreams with themes of helplessness, loss of control, inhibition, victimization, and making mistakes in social media, and (b) examining relationships between social media use, social media-related nightmares, sleep quality, and affective well-being. A convenience sample of 595 Iranian adult social media users (Mage = 27.45, SDage = 11.42) reported on social media-related nightmare, social media use integration, anxiety, peace of mind, sleep quality, and nightmare distress. The Social Media-Related Nightmare Scale (SMNS) demonstrated a unidimensional structure with sound psychometric properties. The most common nightmares involved the inability to log in to social media and the disruption of relationships with other users. Social media use intensity predicted frequency of social media-related nightmares. These nightmares were correlated with increased anxiety, lower peace of mind, poor sleep quality, and nightmare distress. Importantly, social media-related nightmares mediated the relationship between social media use intensity and low affective well-being (i.e., anxiety and peace of mind), poor sleeping, and nightmare distress. The findings suggest that social media-related nightmares could be a potential pathway through which social media engagement may lead to affective distress and sleep difficulties.

More yeast, more problems?: reevaluating the role of Malassezia in seborrheic dermatitis.

Seborrheic dermatitis (SD) is an inflammatory skin disorder and eczema subtype increasingly recognized to be associated with significant physical, psychosocial, and financial burden. The full spectrum of SD, including dandruff localized to the scalp, is estimated to affect half of the world's population. Despite such high prevalence, the exact etiopathogenesis of SD remains unclear. Historically, many researchers have theorized a central, causative role of Malassezia spp. based on prior studies including the proliferation of Malassezia yeast on lesional skin of some SD patients and empiric clinical response to antifungal therapy. However, upon closer examination, many of these findings have not been reproducible nor consistent. Emerging data from novel, targeted anti-inflammatory therapeutics, as well as evidence from genome-wide association studies and murine models, should prompt a reevaluation of the popular yeast-centered hypothesis. Here, through focused review of the literature, including laboratory studies, clinical trials, and expert consensus, we examine and synthesize the data arguing for and against a primary role for Malassezia in SD. We propose an expansion of SD pathogenesis and suggest reframing our view of SD to be based primarily on dysregulation of the host immune system and skin epidermal barrier, like other eczemas.

Short-term reduction of dietary gluten improves metabolic-dysfunction associated steatotic liver disease: A randomised, controlled proof-of-concept study.

The current management of metabolic dysfunction-associated steatotic liver disease (MASLD) relies on lifestyle intervention. Prior studies have shown that nutritional wheat amylase trypsin inhibitors (ATI) activate toll-like receptor 4 on intestinal myeloid cells to enhance intestinal and extra-intestinal inflammation, including the promotion of murine MASLD, insulin resistance and liver fibrosis. We aimed to assess the impact of ATI (gluten)-free diet in liver as well as metabolic parameters of biopsy-proven MASLD patients. We performed a 6-week, proof-of-concept 1:1 randomised controlled trial of an ATI-free diet. The controls followed a balanced diet recommended by the German Nutrition Society. We assessed changes in controlled attenuation parameter (CAP), body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR). Patient-reported outcomes were assessed by the CLDQ-NASH questionnaire. Forty-five patients were consecutively enrolled (21 in the intervention arm and 24 in the control arm). Three patients from each arm discontinued the study. In the ATI-free diet group, a significant decrease in BMI (p = 0.018), CAP (p = 0.018) and HOMA-IR (p = 0.042) was observed at 6 weeks. The mean difference in CAP between the two arms at week 6 was 30.5 dB/m (p = 0.039), with a delta significantly higher in the ATI-free diet group (p = 0.043). Only an ATI-free diet could achieve a significant improvement in CLDQ-NASH domains (p value for total scoring: 0.013). A short-term ATI-free diet leads to significant improvements in liver and metabolic parameters, as well as patient-reported outcomes with good tolerability. A larger follow-up study is justified to corroborate these findings. NCT04066400.

Components of an Updated Disaster Medicine Curriculum Included in Emergency Medicine Residency and Emergency Medical Services Fellowship in the United States.

Disaster medicine (DM) is a unique field that has undergone significant development as disaster events become increasingly complicated to respond to. However, DM is not recognized by the American Board of Medical Specialties (ABMS) or Accreditation Committee of Graduate Medical Education (ACGME), and therefore lacks board certification. Furthermore, prior studies have shown that there is unique body of DM knowledge not being addressed in emergency medicine (EM) residency or Emergency Medical Services (EMS) fellowship, resulting in fundamental DM topics not being covered amongst graduate medical education (GME) programs most prepared to produce DM physicians. A recently published DM core curriculum addresses this knowledge gap and seeks to promote standardization of DM training. The objective of this study is to analyze EM residency and EMS fellowship curricula for the inclusion of DM major curriculum topics and subtopics, using the most recently published DM core curriculum as a control. Both EM residency and EMS fellowship curricula were analyzed for inclusion of DM curriculum topics and subtopics, using the DM curriculum recommendations published by Wexler, et al as a control. A major curriculum topic was deemed covered if at least one related subtopic was described in the curricula. The included and excluded DM topics and subtopics were analyzed using descriptive statistics. While all the DM major curriculum topics were covered by either EM residency or EMS fellowship, EMS fellowship covered more major curriculum topics (14/15; 93%) than EM residency (12/15; 80%) and EMS fellowship covered more DM curriculum subtopics (58/153; 38%) than EM residency (24/153; 16%). Combined, EM residency and EMS fellowship covered 65 out of 153 (42%) of the DM curriculum subtopics. Although this study finds that all the DM major curriculum topics will be covered in EM residency followed by EMS fellowship, over one-half of the subtopics are not covered by either program (16% and 38%, respectively) or both programs combined (42%). Increasingly relevant subtopics, such as climate change, droughts, and flooding, are amongst those not covered by either curriculum. Even amongst the DM topics included in GME curricula, an emphasis on themes such as mass treatment, preparedness, and mitigation is likely under-represented. Accreditation from ACGME for DM fellowship would further promote uniform implementation of the updated core curriculum and ensure optimal training of disaster-ready physicians.

Establishment of a Biaxial Testing System for Characterization of Right Ventricle Viscoelasticity Under Physiological Loadings.

Prior studies have indicated an impact of cardiac muscle viscoelasticity on systolic and diastolic functions. However, the studies of ventricular free wall viscoelasticity, particularly for that of right ventricles (RV), are limited. Moreover, investigations on ventricular passive viscoelasticity have been restricted to large animals and there is a lack of data on rodent species. To fill this knowledge gap, this study aims to develop a biaxial tester that induces high-speed physiological deformations to characterize the passive viscoelasticity of rat RVs. The biaxial testing system was fabricated so that planar deformation of rat ventricle tissues at physiological strain rates was possible. The testing system was validated using isotropic polydimethylsiloxane (PDMS) sheets. Next, viscoelastic measurements were performed in healthy rat RV free walls by equibiaxial cyclic sinusoidal loadings and stress relaxation. The biaxial tester's consistency, accuracy, and stability was confirmed from the PDMS samples measurements. Moreover, significant viscoelastic alterations of the RV were found between sub-physiological (0.1Hz) and physiological frequencies (1-8Hz). From hysteresis loop analysis, we found as the frequency increased, the elasticity and viscosity were increased in both directions. Interestingly, the ratio of storage energy to dissipated energy (Wd/Ws) remained constant at 0.1-5Hz. We did not observe marked differences in healthy RV viscoelasticity between longitudinal and circumferential directions. This work provides a new experimental tool to quantify the passive, biaxial viscoelasticity of ventricle free walls in both small and large animals. The dynamic mechanical tests showed frequency-dependent elastic and viscous behaviors of healthy rat RVs. But the ratio of dissipated energy to stored energy was maintained between frequencies. These findings offer novel baseline information on the passive viscoelasticity of healthy RVs in adult rats.

Uncertain tone and SEO underpricing: Do financial constraints matter?

AbstractIn this study, we conduct several empirical tests to explore the role of financial constraints in predicting the underpricing of seasoned equity offerings (SEO underpricing) through the uncertain tone in issuing firms' filings. We show that investors can infer the firm quality or fundamental value when facing information uncertainty or value ambiguity for only firms in financially distressed groups. Our findings are consistent with prior studies using textual analysis that postulate the varying predictive power of different textual tones for the value of new seasoned equity offerings and, thus, SEO underpricing.