bluuebunny/crossref_metadata_2025 huggingface dataset:
Conduction system pacing versus biventricular pacing: Reduced repolarization heterogeneity in addition to improved depolarization
Authors: Gupta Anshul , Pavri Behzad B.
Published: December 2021

Introduction

His‐bundle pacing (HBP) and left‐bundle‐area pacing (LBAP) are conduction system pacing (CSP) modalities increasingly used as alternatives to conventional biventricular pacing (BiVP). While effects of CSP on ventricular depolarization have been reported, effects on ventricular repolarization have not.

Methods

QRS duration (QRSd) and validated ECG parameters of ventricular repolarization associated with arrhythmic risk (T‐peak‐to‐T‐endTransmural, T‐peak‐to‐T‐endTotal, T‐peak dispersion, QTc, QTc dispersion) were analyzed post‐implant in 107 patients: 60 with CSP (HBP: n = 35, LBAP: n = 25) and 47 with BiVP. T‐wave memory resolution and QTc shortening were analyzed on ECGs obtained ≥25 days post‐implant. Twenty blinded measurements were obtained by both authors to assess Interobserver variability.

Results

Although QRSd was shorter with HBP versus LBAP (119 ± 7 ms vs. 132 ± 9 ms, p = .02), there were no significant differences in any repolarization parameters between these methods of CSP. However, when comparing CSP (HBP + LBAP) to BiVP, both QRSd (125 ± 5 ms vs. 147 ± 7 ms, p < .0001) and repolarization parameters (T‐peak‐to‐T‐endTransmural: 83 ± 5 ms vs. 107 ± 8 ms; T‐peak‐to‐T‐endTotal: 110 ± 7 ms vs. 137 ± 10 ms; QTc: 470 ± 12 ms vs. 506 ± 12 ms; all p ≤ .0001) were significantly shorter with CSP. Improved T‐peak‐to‐T‐end values were unrelated to pre‐implant QRSd or LV function. Interobserver variability was 4.6 ± 1.9 ms. Frontal QRS‐T angle narrowing (132° to 104°, p = .001) and QTc shortening (483 ± 13 ms to 464 ± 12 ms, p = .008) were seen only with CSP.

Conclusions

In addition to improved depolarization, CSP reduced repolarization heterogeneity and provided greater T‐wave memory resolution as compared to BiVP. Both modalities of CSP (HBP + LBAP) resulted in comparably reduced repolarization heterogeneity regardless of baseline QRSd and LV function. These observations may confer lower arrhythmogenic risk and warrant further study.
Mortality benefit of catheter ablation versus medical therapy in atrial fibrillation: An RCT only meta‐analysis
Authors: Ravi Venkatesh , Poudyal Abhushan , Lin Li , Larsen Timothy , Wasserlauf Jeremiah , Trohman Richard G. , Krishnan Kousik , Sharma Parikshit , Huang Henry D.
Published: December 2021

Introduction

Catheter ablation for atrial fibrillation (AF) in comparison to medical therapy alone is known to improve freedom from arrhythmia and quality of life, but the benefit regarding mortality is unclear. The publication of several recent large randomized controlled trials (RCT) comparing ablation with medical therapy has warranted an updated meta‐analysis.

Methods

We sought to compare the effectiveness of catheter ablation versus medical therapy only in patients with AF. MEDLINE, Cochrane, and ClinicalTrials.gov databases were searched from inception until 04/30/2021. Relevant RCTs comparing catheter ablation versus medical therapy in patients with AF were selected.

Results

A total of 24 RCTs involving 5730 adult patients were included (2992 in catheter ablation and 2738 in medical therapy). There was a reduction in all‐cause mortality with catheter ablation compared with medical therapy only (risk ratio (RR) 0.70 [95% confidence interval (CI) 0.55–0.89]; p = .003). Catheter ablation also demonstrated a reduction in hospitalizations (RR 0.50 [95% CI 0.36–0.70]; p < .001), improvement in left ventricular ejection fraction (LVEF) (mean difference [MD] + 5.94% [95% CI 0.40–11.48] p = .04), greater freedom from atrial arrhythmia (RR 2.23 [95% CI 1.79–2.76]; p < .001), and AF (RR 1.95 [95% CI 1.44–2.66]; p < .001). In subgroup analysis, catheter ablation demonstrated a significant reduction in mortality and hospitalizations among patients with reduced LVEF, and when ablation was compared with antiarrhythmic drug use.

Conclusions

In comparison to medical therapy only, catheter ablation for atrial fibrillation reduces mortality, hospitalizations, and increases freedom from arrhythmia.
The prospective association between periodontal disease and brain imaging outcomes: The Atherosclerosis Risk in Communities study
Authors: Adam Hamdi S. , Lakshminarayan Kamakshi , Wang Wendy , Norby Faye L. , Mosley Thomas , Walker Keenan A. , Gottesman Rebecca F. , Meyer Katie , Hughes Timothy M. , Pankow James S. , Wong Dean F. , Jack Clifford R. , Sen Souvik , Lutsey Pamela L. , Beck Jim , Demmer Ryan T.
Published: December 2021

Aim

We investigate if periodontal disease is prospectively associated with cerebrovascular and neurodegenerative markers of dementia and Alzheimer's pathology.

Materials and Methods

N = 1306 participants (Visit 5 mean age = 76.5 [standard deviation = 5.4] years) in the Atherosclerosis Risk in Communities study with completed dental exams at Visit 4 underwent brain magnetic resonance imaging scans at Visit 5 while N = 248 underwent positron emission tomography scans. Participants were classified as edentulous or, among the dentate, by the modified Periodontal Profile Class. Brain volumes were regressed on periodontal status in linear regressions. Cerebrovascular measures and β‐amyloid positivity were regressed on periodontal status in logistic regressions.

Results

Periodontal disease was not associated with brain volumes, microhaemorrhages, or elevated β‐amyloid. Compared with periodontally healthy individuals, odds ratios [95% confidence interval] for all‐type infarcts were 0.37 [0.20, 0.65] for severe tooth loss and 0.56 [0.31, 0.99] for edentulous participants.

Conclusions

Within the limitations of this study, periodontal disease was not associated with altered brain volumes, microhaemorrhages, or β‐amyloid positivity. Tooth loss was associated with lower odds of cerebral infarcts.
A mechanistic model to link technical specifications of vehicle end‐of‐life treatment with the potential of closed‐loop recycling of post‐consumer scrap alloys
Authors: Tu Qingshi , Hertwich Edgar G.
Published: December 2021

Closed‐loop recycling of scrap from end‐of‐life (EoL) vehicles could reduce the demand for virgin material production and associated greenhouse gas (GHG) emissions. However, current modeling frameworks for closed‐loop recycling lack a mechanistic representation of the linkage between the changes in scrap quality (i.e., alloying element composition) and the EoL treatment practices, demonstrating a challenge to comprehensively assess the merits of closed‐loop recycling. The Vehicle Recycling LCA model (VehiReLCA) was developed to address this challenge by parameterizing the key factors involved in the EoL treatment steps, quantifying their influences on the alloying composition of resulting scrap ingots and ultimately, the associated closed‐loop utilization ratios and life cycle GHG emissions. A series of scenarios were investigated, representing a wide range of results that originated from different assumptions of scrap mixing, sorting efficiency, and remelting for six vehicle archetypes. Based on the prevailing assumption of constant closed‐loop utilization ratios in the literature, the life cycle GHG emissions for conventional (lightweight) internal combustion engine vehicle, plug‐in electric vehicle and battery electric vehicle were 3788 (4598), 4136 (4799), and 3327 (4166) kg CO2‐eq per vehicle, respectively. In comparison, explicitly correlating the alloy compositions with random sorting error and/or cross‐mixing of vehicle components often led to an order of magnitude decrease in scrap utilization ratios. Accordingly, the increase in GHG emissions, compared to those estimated using constant utilization ratios, varied from 15%–47% (for all archetypes when 2% random sorting error was considered) to 64%–71% (for lightweight archetypes when the most heterogeneity of EoL treatment steps was assumed). This revealed a significant range of uncertainty regarding the GHG reduction benefits of closed‐loop recycling that was not previously identified in the literature.
A robust framework for characterising diffusion metrics of the median and ulnar nerves: Exploiting state‐of‐the‐art tracking methods
Authors: D'Souza Arkiev , Wang Chenyu , Tu Sicong , Soligo Domenic J. , Kiernan Matthew C. , Barnett Michael , Calamante Fernando
Published: December 2021

Diffusion‐weighted imaging has been used to quantify peripheral nerve properties; however, traditional post‐processing techniques have several limitations. Advanced neuroimaging techniques, which overcome many of these limitations, have not been applied to peripheral nerves. Here, we use state‐of‐the‐art diffusion analysis tools to reconstruct the median and ulnar nerves and quantify their diffusion properties. Diffusion‐weighted MRI scans were obtained from eight healthy adult subjects. Constrained spherical deconvolution was combined with probabilistic fibre tracking to compute track‐weighted fibre orientation distribution (TW‐FOD). The tensor was computed and used along with the tracks to estimate TW apparent diffusion coefficient (TW‐ADC), TW fractional anisotropy (TW‐FA), TW axial diffusivity (TW‐AD), and TW radial diffusivity (TW‐RD). Variability of TW measurements was used to estimate power size information. The population intersession mean (± SD) measurements for the median nerve were TW‐FOD 1.30 (±0.17), TW‐ADC 1.16 (±0.13) × 10−3 mm2/s, TW‐FA 0.60 (±0.05), TW‐AD 2.05 (±0.16) × 10−3 mm2/s, and TW‐RD 0.72 (±0.12) × 10−3 mm2/s. The corresponding measurements for the ulnar nerve were TW‐FOD 1.25 (±0.14), TW‐ADC 1.13 (±0.10) × 10−3 mm2/s, TW‐FA 0.56 (±0.06), TW‐AD 1.93 (±0.01) × 10−3 mm2/s, and TW‐RD 0.74 (±0.12) × 10−3 mm2/s. Based on these measurements, a sample size of 37 would be sufficient to detect a 10% difference in any of the measured TW metrics. A sample size of 20 would be large enough to detect within‐subject differences as small as 2.9% (TW‐AD, ulnar nerve) and between‐subject differences as small as 3.8% (TW‐AD, ulnar nerve).
Understanding consumer stockpiling: Insights provided during the COVID‐19 pandemic
Authors: Amaral Nelson Borges , Chang Bin , Burns Rachel
Published: December 2021

This article examines data collected early in the COVID‐19 pandemic to uncover the underlying factors that are related to consumer stockpiling in response to a global pandemic. A survey of 1325 American consumers from March 27, 2020 to March 29, 2020 revealed that 55.5% of respondents stockpiled. Locus of control (LOC), the extent to which a person believes the environment is controllable and responsive, is associated with the stockpiling decision. More specifically, after controlling for demographic characteristics, consumers with internal LOC are less likely to stockpiling than those with external LOC. We also find that consumers with higher health risk are more likely to stockpile. Together, our results provide valuable insight for practitioners and policy makers who are concerned with understanding and reducing consumer stockpiling during health‐related crises.
Shadow Conversations and the Citational Practices of a Journal
Authors: Das Sonia N.
Published: December 2021

Drawing on the resonances between Judith T. Irvine’s (1996) writings about “shadow conversations” and the broader linguistic anthropological literature on citational practices (Goodman et al. 2014; Nakassis 2013; Rhodes 2020), I explore how the Journal of Linguistic Anthropology has sought to and continues to engage with the politics of inclusion and diversity in the construction of disciplinary knowledge, focusing in particular on publishing in academic journals. Following an earlier attempt to include an inclusion criterion on the journal’s Scholar One review portal, I now instead endorse the views of my colleagues to adopt a variety of strategies to showcase the work of underrepresented yet critical voices in the discipline. I conclude by highlighting the influential role that linguistic anthropologists play in promoting dialogue about the interdiscursive dimensions of knowledge production in the academy.
Lower serotonin levels in severe sleep bruxism and its association with sleep, heart rate, and body mass index
Authors: Smardz Joanna , Martynowicz Helena , Wojakowska Anna , Wezgowiec Joanna , Danel Dariusz , Mazur Grzegorz , Wieckiewicz Mieszko
Published: December 2021

Background

Sleep bruxism (SB) is a complex behaviour that seems to be associated with the serotoninergic pathway.

Objectives

This exploratory research aimed to evaluate the levels of serotonin in individuals with sleep bruxism diagnosed by video polysomnography. The study also evaluated whether the levels of serotonin were associated with body mass index, heart rate, and sleep parameters.

Methods

The study participants were adults hospitalised in the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology at the Wroclaw Medical University. They underwent a single‐night video polysomnography during which sleep and SB parameters and heart rate were evaluated. Additionally, body mass index and blood serotonin levels were evaluated for each patient.

Results

A total of 105 patients were included in this study (80 women and 25 men). All the patients were Caucasians aged 18–63 years, with a mean age ± (standard deviation) of 33.43± 10.8 years. Seventy‐five patients (71.43%) presented sleep bruxism (bruxism episodes index ≥2) and 30 (28.57%) did not. Fifty patients (47.62%) presented severe sleep bruxism (bruxism episodes index >4). The results showed that lower blood serotonin levels were associated with severe sleep bruxism; increased bruxism episodes index, rapid eye movement sleep, and body mass index; and decreased maximal pulse.

Conclusion

Severe sleep bruxism and the associated phenomena seem to co‐occur with lower blood serotonin levels. The study supports the hypothesis on the relationship between the serotoninergic pathway and sleep bruxism.
Trends in Asthma‐Related School Health Policies and Practices in the US States *
Authors: Qin Xiaoting , Zahran Hatice S. , Leon‐Nguyen Michelle , Kilmer Greta , Collins Pamela , Welch Paige , Malilay Josephine
Published: December 2021

BACKGROUND

Asthma is one of the leading causes of school absenteeism. Schools can play an important role in coordinating asthma care. The purpose of this study was to assess the implementation of asthma‐related school health policies and practices across states and how they have changed over time.

METHODS

Data were analyzed from 36 states that conducted School Health Profiles surveys during 2008 to 2018. Trends in 6 topics were analyzed by logistic regression and JointPoint trend test.

RESULTS

Trends in efforts to identify and track students with asthma and improve students' and parents' knowledge about asthma were stable or increased. Interest among lead health education teachers in receiving professional development on asthma trended downward in 35 of 36 states.

CONCLUSIONS

Stable to upward trends suggest that a majority of schools have maintained or improved their efforts to identify and track students with asthma and increase the knowledge of students and parents about asthma. However, further improvement is needed in referral of students with asthma to health care professionals and encouraging asthma‐related professional development of lead health education teachers.
Preparation of antioxidant‐rich tricolor pasta using microwave processed orange pomace and cucumber peel powder: A study on nutraceutical, textural, color, and sensory attributes
Authors: Kaur Maninder , Dhaliwal Muskan , Kaur Harpreet , Singh Manpreet , Punia Bangar Sneh , Kumar Manoj , Pandiselvam Ravi
Published: December 2021

The by‐products obtained from orange and cucumber industries, such as pomace and peel, are usually discarded after primary processing. In this study, orange pomace and cucumber peel were microwave dried (180 W for 40 min) to prepare powders and incorporated at varying levels (5%–20%) to prepare tricolor pasta. The prepared pasta was evaluated for its nutraceutical, cooking, textural, and sensory characteristics. The viscoelastic behavior of orange pomace (OPP) and cucumber peel (CPP) powder enriched pasta dough was also analyzed. The elastic modulus (G′) and viscous modulus (G″) of dough increased with the incorporation of the higher proportion of pomace and peel powder. The total dietary fiber in pasta incorporated with OPP increased from 10.30% to 20.19%, while it was increased to 24.91% upon the incorporation of CPP. These powders also contributed to the natural orange and green color of pasta. The antioxidant activity of OPP pasta increased from 10.64% to 31.9% and 10.64% to 20.29% in CPP (at a 20% level). Total phenolic content, carotenoid content, and chlorophyll content of OPP and CPP enriched pasta were determined, which progressively increased with increased levels of both the powders. The firmness of OPP increased from 0.29 to 1.54 N and 0.29 to 1.87 N in CPP at their highest level (20%) of addition. Therefore, orange pomace and cucumber peel waste from industries can be efficiently used to prepare pasta with improved nutritional characteristics.
Compliance with and acceptability of two fortified balanced energy protein supplements among pregnant women in rural Nepal
Authors: Lama Tsering P. , Moore Katie , Isanaka Sheila , Jones Leslie , Bedford Juliet , de Pee Saskia , Katz Joanne , Khatry Subarna K. , LeClerq Steven C. , Tielsch James M.
Published: December 2021

Some evidence suggests that balanced energy protein (BEP) supplements taken during pregnancy and lactation can have positive effects on birth outcomes such as small‐for‐gestational age and birthweight, but more evidence is needed on the long‐term use and acceptability of such supplements. We conducted a mixed‐methods formative research study to assess and compare compliance with and acceptability of two BEP supplements, a lipid‐based peanut paste and a biscuit, to identify BEP supplements for subsequent inclusion in an efficacy trial. We conducted an 8‐week feeding trial of daily supplementation among two groups of 40 pregnant women each in rural Nepal. Compliance data were collected and supplements distributed at the weekly visits. Sensory properties of the supplements were assessed using a 7‐point Likert scale. In addition, in‐depth interviews with women (n = 16), family members (n = 6) and health workers (n = 6) and focus group discussions (FGDs) (n = 4) were conducted to explore themes related to general use and intention of future use of the supplement. Overall self‐reported compliance was high: medians of 91.1% in the lipid‐based peanut paste group and 96.4% in the biscuit group. Both supplements were rated highly on overall likability (median score 6/7) and sensory properties. Qualitative findings showed that sustained use of the supplements was attributed to expected health benefits, favourable sensory attributes, and family support. The FGDs suggested providing the option to choose between more than one type/flavour of supplements to improve compliance. Sharing was mostly evident in the first week with higher sharing reported in the biscuit group.
When tropical and subtropical congeners met: Multiple ancient hybridization events within Eriobotrya in the Yunnan‐Guizhou Plateau, a tropical‐subtropical transition area in China
Authors: Chen Sufang , Milne Richard , Zhou Renchao , Meng Kaikai , Yin Qianyi , Guo Wei , Ma Yongpeng , Mao Kangshan , Xu Kewang , Kim Young‐Dong , Do Truong Van , Liao Wenbo , Fan Qiang
Published: December 2021

Global climate changes during the Miocene may have created ample opportunities for hybridization between members of tropical and subtropical biomes at the boundary between these zones. Yet, very few studies have explored this possibility. The Yunnan‐Guizhou Plateau (YGP) in Southwest China is a biodiversity hotspot for vascular plants, located in a transitional area between the floristic regions of tropical Southeast Asia and subtropical East Asia. The genus Eriobotrya (Rosaceae) comprises both tropical and subtropical taxa, with 12 species recorded in the YGP, making it a suitable basis for testing the hypothesis of between‐biome hybridization. Therefore, we surveyed the evolutionary history of Eriobotrya by examining three chloroplast regions and five nuclear genes for 817 individuals (47 populations) of 23 Eriobotrya species (including 19 populations of 12 species in the YGP), plus genome re‐sequencing of 33 representative samples. We concluded that: (1) phylogenetic positions for 16 species exhibited strong cytonuclear conflicts, most probably due to ancient hybridization; (2) the YGP is a hotspot for hybridization, with 11 species showing clear evidence of chloroplast capture; and (3) Eriobotrya probably originated in tropical Asia during the Eocene. From the Miocene onwards, the intensification of the Eastern Asia monsoon and global cooling may have shifted the tropical‐subtropical boundary and caused secondary contact between species, thus providing ample opportunity for hybridization and diversification of Eriobotrya, especially in the YGP. Our study highlights the significant role that paleoclimate changes probably played in driving hybridization and generating rich species diversity in climate transition zones.
Collective identities amid war and displacement: Syrians and Syrian refugees re‐imagine their country
Authors: Bachleitner Kathrin
Published: December 2021

This article is interested in Syrian and Syrian refugees' ties of belonging to their country in times of war and displacement. By looking at individuals, the paper follows a micro‐level approach to research societal ties of belonging to a country that has slipped into war. It argues that during conflicts, the meaning and boundaries of national identity are grasped in individuals' re‐imagination of their country in either more “civic” or “ethnic” terms. As a result of this process, national identity may gain an inclusive, civic meaning based on the idea of citizenship or a more exclusive content based on the narrower confines of ethnicity and sect. Empirically, 100 Syrians and 100 Syrian refugees provided their vision of a future Syrian state in online interviews. The findings show that the majority of respondents' visions of Syria follows a civic rationale, with most survey participants linking their belonging to a future Syria with the broader ideas of citizenship, political rights and participation, rather than identifying the country in ethnic/sectarian terms. Combined with the theories, these results offer a glimpse into the societal formation of a new Syrian “we” amid an ongoing war and continuing waves of displacement.
Orthodontic evaluation of children and adolescents with different types of Foetal Alcohol Syndrome Disorders
Authors: Ludwików Katarzyna , Zadurska Małgorzata , Czochrowska Ewa
Published: December 2021

Objective

To assess general and oral health status, including the presence of malocclusion and orthodontic treatment needs, in children and adolescents with FASD in relation to different types of this disorder.

Setting and Sample Population

A total of 67 participants (29 males and 38 females) aged 2.5‐17.8 years with confirmed diagnosis of FASD were included.

Materials and Methods

The participants were divided into three subgroups: foetal alcohol syndrome (FAS), partial foetal alcohol syndrome (PFAS) and alcohol‐related neurodevelopmental disorders (ARND). General health, oral health status, history of dental trauma, presence of dysfunctions or parafunctions, and occlusion were examined. Additionally, the Index of Orthodontic Treatment Need (IOTN) index was calculated. Selected variables were compared to the results obtained from a national monitoring survey on the oral health conditions in Poland.

Results

In children and adolescents with FASD, a number of systemic anomalies including alimentary, neurological and musculoskeletal disorders were present. Dysfunctions and parafunctions such as mouth breathing and thumb sucking were frequently recorded. Children with FASD had an increased prevalence of distal occlusion and crossbite compared to the general population. Malocclusions were more often identified in the FAS group. No significant differences in the IOTN between different FASD groups were found. Borderline need for orthodontic treatment was more frequent in children with FASD compared to controls.

Conclusion

Early screening for the presence of dysfunctions/parafunctions and malocclusions in children with FASD is recommended, so that orthodontic prophylaxis and state‐funded orthodontic care programmes for these children are implemented.
Identifying personal health‐related resources of women with breast cancer for nursing: An integrative review
Authors: Skyttä Marika , Pietilä Anna‐Maija , Stolt Minna , Kangasniemi Mari
Published: December 2021

Personal health‐related resources are essential for women with breast cancer, as these help them to maintain their own health and well‐being during different phases of their illness. The purpose of this integrative review was to identify, describe and synthetise what personal health‐related resources have already been identified for this patient group. We carried out an integrative review to find papers that focused on personal health‐related resources for women with breast cancer aged 18–64 years. The search covered 1 January 2005 to 31 May 2021 and was carried out using the CINAHL, PubMed, PsycINFO, Web of Science and Cochrane Library databases. It was limited to peer‐reviewed scientific papers with abstracts published in English and 23 papers met the inclusion criteria. The data were analysed using content analysis. Personal health‐related resources for women with breast cancer consisted of three different, but inherently interconnected, categories of personal strengths, person‐centred cancer care and social support from and involvement in their cultural community. Personal health‐related resources for women with breast cancer were multifaceted. Women need nursing support to identify and use these resources and future studies are needed to strengthen how they are measured.
Phosphoinositides containing stearic acid are required for interaction between Rho GTPases and the exocyst to control the late steps of polarized exocytosis
Authors: Laquel Patricia , Testet Eric , Tuphile Karine , Cullin Christophe , Fouillen Laetitia , Bessoule Jean‐Jacques , Doignon François
Published: December 2021

Cell polarity is achieved by regulators such as small G proteins, exocyst members and phosphoinositides, with the latter playing a key role when bound to the exocyst proteins Sec3p and Exo70p, and Rho GTPases. This ensures asymmetric growth via the routing of proteins and lipids to the cell surface using actin cables. Previously, using a yeast mutant for a lysophosphatidylinositol acyl transferase encoded by the PSI1 gene, we demonstrated the role of stearic acid in the acyl chain of phosphoinositides in cytoskeletal organization and secretion. Here, we use a genetic approach to characterize the effect on late steps of the secretory pathway. The constitutive overexpression of PSI1 in mutants affecting kinases involved in the phosphoinositide pathway demonstrated the role of molecular species containing stearic acid in bypassing a lack of phosphatidylinositol‐4‐phosphate (PI(4)P) at the plasma membrane, which is essential for the function of the Cdc42p module. Decreasing the levels of stearic acid‐containing phosphoinositides modifies the environment of the actors involved in the control of late steps in the secretory pathway. This leads to decreased interactions between Exo70p and Sec3p, with Cdc42p, Rho1p and Rho3p, because of disruption of the GTP/GDP ratio of at least Rho1p and Rho3p GTPases, thereby preventing activation of the exocyst.
Evaluation of Learner vs. Teacher Centered Syllabi in Construction Management Courses: An Initial Investigation
Authors: Farrow Ben , Leathem Tom , Salman Amna
Published: December 2021

Research indicates that retention and performance of undergraduate students increases when they perceive a cooperative and supportive educational community. The course syllabus is one of the first opportunities to influence student perception on their educational experience. Literature on syllabi suggests that learner-centered syllabi yield more positive student perceptions of teachers and the course as compared to traditional teacher-centered syllabi. Current research on the impacts of different syllabi constructs within construction education is lacking, and no studies could be found on whether these perceptions translate to student grades. This study used action research to better understand the impact of a learner-centered syllabus vs. a teacher-centered syllabus in an undergraduate construction management program. Student perception, faculty perception and student grades were measured between the learner-centered class and the teacher-centered class. The data was collected from four different classes, split among two courses, and taught by two faculty over the spring 2020 semester. Results suggested that the learner-centered syllabi appeared to motivate student engagement as well as impact both, the first impressions of the instructor and teacher-student relationship. However, it showed no difference in student grades.
No effect of patent foramen ovale on acute mountain sickness and pulmonary pressure in normobaric hypoxia
Authors: DiMarco Kaitlyn G. , Beasley Kara M. , Shah Karina , Speros Julia P. , Elliott Jonathan E. , Laurie Steven S. , Duke Joseph W. , Goodman Randall D. , Futral Joel Eben , Hawn Jerold A. , Roach Robert C. , Lovering Andrew T.
Published: December 2021

New Findings

What is the central question to this study?

Is there a relationship between a patent foramen ovale and the development of acute mountain sickness and an exaggerated increase in pulmonary pressure in response to 7–10 h of normobaric hypoxia?

What is the main finding and its importance?

Patent foramen ovale presence did not increase susceptibility to acute mountain sickness or result in an exaggerated increase in pulmonary artery systolic pressure with normobaric hypoxia. This suggests hypobaric hypoxia is integral to the increased susceptibility to acute mountain sickness previously reported in those with patent foramen ovale, and patent foramen ovale presence alone does not contribute to the hypoxic pulmonary pressor response.

Acute mountain sickness (AMS) develops following rapid ascent to altitude, but its exact causes remain unknown. A patent foramen ovale (PFO) is a right‐to‐left intracardiac shunt present in ∼30% of the population that has been shown to increase AMS susceptibility with high altitude hypoxia. Additionally, high altitude pulmonary oedema (HAPE) is a severe type of altitude illness characterized by an exaggerated pulmonary pressure response, and there is a greater prevalence of PFO in those with a history of HAPE. However, whether hypoxia per se is causing the increased incidence of AMS in those with a PFO and whether a PFO is associated with an exaggerated increase in pulmonary pressure in those without a history of HAPE is unknown. Participants (n = 36) matched for biological sex (18 female) and the presence or absence of a PFO (18 PFO+) were exposed to 7–10 h of normobaric hypoxia equivalent to 4755 m. Presence and severity of AMS was determined using the Lake Louise AMS scoring system. Pulmonary artery systolic pressure, cardiac output and total pulmonary resistance were measured using ultrasound. We found no significant association of PFO with incidence or severity of AMS and no association of PFO with arterial oxygen saturation. Additionally, there was no effect of a PFO on pulmonary pressure, cardiac output or total pulmonary resistance. These data suggest that hypobaric hypoxia is necessary for those with a PFO to have increased incidence of AMS and that presence of PFO is not associated with an exaggerated pulmonary pressor response.
Influence of Lubricant Film Cavitation on the Vibration Behavior of a Semifloating Ring Supported Turbocharger Rotor With Thrust Bearing
Authors: Ziese Christian , Irmscher Cornelius , Nitzschke Steffen , Daniel Christian , Woschke Elmar , Klimpel Thomas
Published: December 2021

This contribution investigates the influence of outgassing processes on the vibration behavior of a hydrodynamic bearing supported turbocharger rotor. The examined rotor is supported radially by floating rings with outer squeeze-film damping and axially by thrust bearings. Due to the highly nonlinear bearing properties, the rotor can be excited via the lubricating film, which results in subsynchronous vibrations known as oil-whirl and oil-whip phenomena. A significant influence on the occurrence of oil-whip phenomena is attributed to the bearing stiffness and damping, which depend on the kinematic state of the supporting elements, the thermal condition, and the occurrence of outgassing processes. For modeling the bearing behavior, the Reynolds equation with mass-conserving cavitation regarding the two-phase model and the three-dimensional (3D) energy as well as heat conduction equation is solved. To evaluate the impact of cavitation, run-up simulations are carried out assuming a fully (half-Sommerfeld) or partially filled lubrication gap. The resulting rotor responses are compared with the shaft motion measurement. Also, the normalized eccentricity, the minimum lubricant fraction, and the thermal bearing condition are discussed.
Analytical Studies on Mode III Fracture in Flexoelectric Solids
Authors: Tian Xinpeng , Xu Mengkang , Zhou Haiyang , Deng Qian , Li Qun , Sladek Jan , Sladek Vladimir
Published: December 2021

Due to the stress concentration near crack tips, strong flexoelectric effect would be observed there, which might lead to new applications of flexoelectricity in material science and devices. However, different from the flexoelectric effect in cantilever beams or truncated pyramids, at the crack tip, multiple components of strain gradients with nonuniform distribution contribute to the flexoelectric effect, which makes the problem extremely complex. In this paper, with the consideration of both direct and converse flexoelectricity, the electromechanical coupling effect around the tip of a Mode III crack is studied analytically. Based on the Williams’ expansion method, the displacement field, polarization field, strain gradient field along with the actual physical stresses field are solved. A path-independent J-integral for Mode III cracks in flexoelectric solids is presented. Our results indicate that the existence of flexoelectricity leads to a decrease of both the J-integral and the out-of-plane displacement in Mode III cracks, which means that the flexoelectric effect around the tip of Mode III cracks enhances the local strength of materials.
Smart Vaccine Manufacturing Using Novel Biotechnology Platforms: A Study During COVID-19
Authors: Kumar Vishnu , Srinivasan Vijay , Kumara Soundar
Published: December 2021

Healthcare experts have come to a consensus that effective and safe vaccines are necessary to control the rapid spread of the ongoing COVID-19 pandemic across the globe. Since the traditional vaccine development and manufacturing approaches were unable to meet the rapidly growing COVID-19 vaccine demand, biopharmaceutical firms had to devise novel and smart techniques to boost the development, production, and distribution of COVID-19 vaccines in a large scale with lightning speed. This triggered their transition to smart vaccine manufacturing approaches using novel viral vector and nucleic acid biotechnology platforms. This paper tries to explore this rationality of the biopharmaceutical industry by comparing the traditional and the novel biotechnology platform-based vaccine manufacturing techniques and reviewing the COVID-19 vaccine manufacturing scenarios. To highlight the “smart” characteristics of the novel platform-based COVID-19 vaccine products and to make an effective comparison with the traditional products, a well-established product classification framework is used as a reference. Finally, the study concludes by presenting the future possibility of incorporating smart manufacturing paradigms with the novel platform-based manufacturing process. It is hoped that this study would serve as an asset for the biopharmaceutical firms to appropriately streamline their strategies, resources, and goals to meet the global vaccine requirements.
Impact of Timing in the Design Process on Students’ Application of Design for Additive Manufacturing Heuristics
Authors: Schauer Anastasia M. , Fillingim Kenton B. , Fu Katherine
Published: December 2021

The goal of this work is to study the way student designers use design for additive manufacturing (DfAM) rules or heuristics. It can be challenging for novice designers to create successful designs for additive manufacturing (AM), due to its recent surge in popularity and lack of formal education or training. A study was carried out to investigate the way novices apply DfAM heuristics when they receive them at different points in the design process. A design problem was presented to students, and three different groups of student participants were given a lecture on DfAM heuristics at three different points in the design process: before the initial design, between the initial design and redesign, and after the redesign. The novelty and quality of each of the resulting designs were evaluated. Results indicate that although the DfAM heuristics lecture had no impact on the overall quality of the designs generated, participants who were given the heuristics lecture after the initial design session produced designs that were better-suited for 3D printing in the second phase of the design activity. However, receiving this additional information appears to prevent students from creatively iterating upon their initial designs, as participants who received heuristic information between the design sessions experienced a decrease in novelty between the two sessions. Additionally, receiving the heuristics lecture increased all students’ perceptions of their ability to perform DfAM-related tasks. These results validate the practicality of design heuristics in lecture form as AM training tools while also emphasizing the importance of iteration in the design process.
A Simplified Method for the Deposition Rate Assessment on the Vanes of a Multistage Axial-Flow Compressor
Authors: Vulpio Alessandro , Suman Alessio , Casari Nicola , Pinelli Michele
Published: December 2021

Gas turbine particle ingestion may lead to the deposition of contaminants in the compressor section, inducing the performance losses of the whole engine. The economic losses derived from this issue push great interest in the investigation of such a phenomenon from a numerical and experimental standpoint. This article describes a quantitative approach to predict particle deposition on the vanes of an axial compressor starting from the flow field obtained employing computational fluid dynamic (CFD) simulations. The results are then compared to the experiments performed on the Allison 250 C18 compressor unit subject to particle ingestion under controlled conditions. The results derived from the experimental and numerical investigations are presented, providing insight into the mass deposited on the vanes and the corresponding zones most affected by the particle deposition issue. The methodology showed good agreement in the estimation of the predicted values of the deposited mass and the corresponding patterns through the compressor stages. The low-complexity approach proposed here could help the designer to predict the contamination of the stationary rows starting from a simple set of single-phase numerical results. Furthermore, with the implementation of this approach into the design path, the designer could reduce the impact of fouling, looking at the effects of their solutions under the fouling-reduction light.
Lightweight Material Optimization of Aquatic Vehicles’ Propeller Based on Fatigue Life Using Hydro Structural Interaction Simulation
Authors: Raja Vijayanandh , Kulandaiyapan Naveen Kumar , Gnanasekaran Raj Kumar , Subramaniam Indira Prasanth , Kandasamy Kesavan , Raji Arul Prakash , Madasamy Senthil Kumar
Published: December 2021

Generally, inward and outward effects are huge and prime in the rotating components. Based on the working environments of a rotor, the complexity is increased furthermore. Similarly, this work also deals the complicated problem, which is fatigue life estimation of Marine Vehicles’ propeller for different lightweight materials under given Ocean environments by using Ansys Fluent 16.2. The conceptual design of the ship propeller is modeled with the help of CATIA. Fatigue life estimation on the rotor is a key and complex output of this work, so advanced methodology is mandatory for computation. For that purpose, the following advanced methodology has been implemented for this work, which is Hydro Structural Interaction (HSI) and Moving Reference Frame (MRF) techniques are associated in Computational Fluid Dynamics (CFD). Hydro-Fluid properties such as density and operating pressure are used as per the working vehicles’ environment, which has been easily, defined in Ansys Fluent 17.2. Thus this computational platform is perfect to handle hydrodynamic simulations, even though the gird convergence study is conducted for the better outcomes. In the case of structural simulation, the existing materials such as Aluminium alloy and Stainless Steel are used for fatigue life estimation under HSI loading conditions. Finally, the fatigue life estimation of Marine Vehicles’ propeller is extended for composite materials to compare the life of a rotor. Both the Hydrostatic and Hydrodynamic loading conditions are tested on Aquatic Vehicle’s rotor and thereby the suitable material is chosen and given to the future input for real-time applications.
Aerodynamic Performance Characterization of a Drag-Based Elliptical-Bladed Savonius Wind Turbine Rotor
Authors: Talukdar Parag K. , Kulkarni Vinayak , Saha Ujjwal K.
Published: December 2021

Among the existing wind energy harvesters, the vertical-axis Savonius wind turbine rotor is found to be suitable for small-scale power generation. It is a drag-driven device where the pressure of the fluid stagnating within its blades results in its rotation. The high starting torque and poor operational efficiency of this type of turbine rotor are its distinguishing features. The main geometric and flow parameters that influence its performance are its blade profile, overlap ratio, aspect ratio and Reynolds number (Re). Among these parameters, the blade profile influences significantly on the power production. Recent studies have shown that, choice of an elliptic blade can help in harnessing more wind energy, however, it is desirable to characterize this choice through detailed studies. The present study aims at evaluating the performance of a two-elliptical-bladed Savonius turbine rotor for its dynamic torque and power characteristics. In order to characterize its performances, the developed rotor is experimented in an open circuit low speed wind tunnel. The experiments have been carried out at different Re values so as to estimate the dependence of rotor performance on Re. When the Re is increased from 57310 to 164766, the maximum power coefficient (CPmax) of the turbine rotor has shown an improvement of 43%.
Characterization of Mechanical Property of PLA-ABS Functionally Graded Material Fabricated by Fused Deposition Modeling
Authors: Su Ziyi , Inaba Kazuaki , Karmakar Amit , Das Apurba
Published: December 2021

Application of functionally graded materials (FGMs) in energy, aviation and nuclear industries has increased since the last decade due to potential reduction of in-plane and transverse through-the-thickness stresses, enhanced residual stress distribution, superior thermal properties, free from delamination, and reduced stress intensity factors. FGMs are categorized as an advanced class of composite materials where the two constituent materials are graded along the thickness direction. Absence of sharp change in material property in the interface layer eliminates the problem of delamination and debonding, which is a major concern for traditional composite material. In this work, PLA-ABS functionally graded material is manufactured using additive manufacturing techniques through fused deposition modeling (FDM) using Y-type extruder. X-ray computed tomography test is conducted to see the air void (generated during printing) distribution in the printed FGM. Tensile test (as per ISO-527standrad) is conducted to evaluate the Young’s Modulus of additive manufactured FGMs. Three different measuring positions are considered in the FGM specimens to check the effect of property change along the grading direction. Tensile test results of PLA-ABS FGM are compared with their individual constituents (ABS and PLA). Further, flexural vibration test is conducted to evaluate the natural frequency of printed FGM beam. Experimentally determined mechanical and dynamic characteristics in terms effective Young’s Modulus and natural frequency are analyzed and discussed.
Effect of Exit Blade Angle on the Performance of Cross Flow Hydro Turbine: A Numerical Study
Authors: Alom Nur , Sarkar Bikash Kumar
Published: December 2021

Cross-flow hydro turbines (CFHTs) are generally used in micro hydraulic power plants due to their simplicity in design and fabrication, moderate efficiency, ease of maintenance. The CFHT can be used in low flow and low head conditions with an efficiency of around 90% at rated conditions. However, the efficiency of the CFHT can further be improved by changing its geometric parameters Hence, in the present investigation, 3D unsteady simulations are performed in order to locate the exit blade angle (β2) with the intention is to improve the efficiency of the turbine. In the proposed investigation, the multi-physics FVM solver ANSYS Fluent has been used with the help of the SST k-ω turbulence model to carry out the unsteady simulations. The 3D unsteady simulations are performed by varying the exit blade angle (β2) from 60° to 90° to improve its efficiency when the rotational speed is fixed with the number of blades being 20. From the unsteady simulations, the maximum efficiency of the CFHT is at the exit blade angle (β2) = 80°.
Genetic Algorithm Based Optimization Technique for Savonius-Style Wind Turbine
Authors: Paul Diplina , Banerjee Abhisek
Published: December 2021

In this article, authors have studied genetic algorithm-based optimization technique to optimize rotor profile for elliptic shaped Savonius-style wind turbine with an aim to maximize the coefficient of performance. Genetic algorithm has been used to optimize design variables having distinct values and discontinuous and nondifferentiable objective functions. Optimization procedure using genetic algorithm uses the following steps: initialization, assessment, assortment, crossover and lastly alteration. Once the genetic algorithm is initialized, then the evaluation process trails, where each parametric value is evaluated based on the fitness function stated as objective function. Then the GA operators i.e assortment, cross over and alteration are applied. At the end of GA operation procedure, a new set of values of design parameter is generated. This procedure is endlessly iterated until the convergence criteria is met. Then the optimized and non-optimized profiles are studied using numerical simulation. Initially a two-dimensional numerical model is developed and validated against experimental results. The two-dimensional analysis is conducted using k-ω shear stress transport model. Unsteady Reynold’s Averaged Navier Stoke’s equations have been solved to simulate the flow field of a Savonius-style rotor. This analysis has been executed using finite volume approach in Fluent 17.2 version. Grid independence study is performed to curtail the effect of grid size on the flow field portrayals. The optimization technique implemented on the Savonius-style wind turbine, generated design parameters that were able to yield a coefficient of performance value of 0.398. The coefficient of torque and coefficient of performance values are studied for both optimized and non-optimized profile as a function of tip speed ratio. Numerical simulation predicted a maximum gain of 41% for coefficient of performance at TSR = 1.0 over for optimized profile over the non-optimized profile.