bluuebunny/crossref_metadata_2025 huggingface dataset:
Learning from the resourceness blind spot for service innovation at the base of the pyramid
Authors: Greene Michelle , van Riel Allard Cornelis Robert
Published: September 2021

Purpose

This paper aims to investigate whether and why the base of the pyramid (BOP) actors display passive innovation resistance because of which they reject service innovations without evaluation and forfeit potential to improve their well-being. The resourceness concept, referring to the outcome of how actors appraise and integrate resources in pursuit of a purpose at hand, is used as a theoretical lens to investigate the everyday consumption behaviour of BOP households and helps to investigate how and why passive innovation resistance occurs. The outcomes of the study help address important theoretical and practical considerations for the development of successful new service concepts at the BOP.

Design/methodology/approach

Narrative interviews with 29 households in Zambia provide data, from which patterns in how potential resources do or do not become real are identified and related to the concept of passive innovation.

Findings

Economic, social and other factors in the BOP context clearly influence non-random patterns of resource integration which are correlated with passive innovation resistance. This can lead to service innovations being ignored and/or misunderstood prior to evaluation for adoption. This is a risk to the potential positive impact of service innovation for poverty alleviation at the BOP.

Practical implications

Service innovation at the BOP must begin with a deep understanding of “how” and “why” consumers typically appraise and integrate potential resources to achieve a beneficial outcome in their context. To overcome the barrier of passive innovation resistance, marketing education must stimulate an understanding of potential benefits and motivation towards the change associated with the adoption of service innovation.

Social implications

The findings support more successful service innovation strategies for the BOP, which can provide vital infrastructure for the alleviation of poverty.

Originality/value

The application of a service-dominant logic perspective in the BOP context and the conceptual linkage between resourceness and passive innovation resistance is novel. Valuable insights are gained for service practitioners at the BOP and for further conceptual development of innovation resistance in the BOP context.
Hindrance stressors, ego depletion and knowledge sharing
Authors: Kang Fei , Zhang Ying , Zhang Han
Published: September 2021

Purpose

This study aims to use the ego depletion theory to examine the impact of hindrance stressors on knowledge sharing behaviors by investigating the mediating role of ego depletion and the moderating role of self-enhancing humor.

Design/methodology/approach

Data were obtained from a two-wave sample of 226 dyads, including employees in the manufacturing industry and their direct supervisors. The hypotheses were tested by hierarchical regression analyzes and Hayes’ PROCESS macro.

Findings

The results demonstrated that employees’ self-enhancing humor style could alleviate the impact of hindrance stressors on employees’ ego depletion state and buffer the negative indirect effect of hindrance stressors on employees’ knowledge-sharing behaviors.

Research limitations/implications

Although the authors collected mediator and dependent variables from different sources, this study used a cross-sectional research design, making it difficult to draw causal conclusions. Besides, hindrance stressors, ego depletion and self-enhancing humor style were all reported by employees.

Originality/value

Through the study, the authors highlight the important role of the self-control view in explaining proactive behavior in the workplace and a great awareness of the unforeseeable consequences of ego depletion for employees.
COVID-19 and rapid digitalization of learning and teaching: quality assurance issues and solutions in a Sino-foreign higher education institution
Authors: Perrin Stuart , Wang Ling
Published: September 2021

Purpose

This paper aims to report and analyze the lessons learnt from a case study of the implementation of the move from onsite to online learning at a Sino-Foreign higher education institution.

Design/methodology/approach

This paper reports a case study based on an analysis of three elements of the move to digital education during the COVID-19 pandemic. In suggesting three elements, it argues that the first and most immediate move away from onsite teaching should be thought of as emergency response teaching, and it is the lessons learnt from this vital and necessary stage that have informed the subsequent implementation of a more digitalization process.

Findings

The case study identifies the journey that the university is going through to deliver digitalized education, and how the pandemic hastened what had already been started. It illustrates how the pandemic has been useful in highlighting where we are, what decisions have been made and what still needs to be done with regard to readiness for the disruption likely by Industry 4.0.

Research limitations/implications

The study was conducted at one institution, which along with eight other similar institutions is unique within China. Findings, especially the processes of making decisions, while relevant to the wider discussion on digitalization and Industry 4.0, should also be considered in this light.

Practical implications

While the focus of the paper is on COVID-19 and Rapid Digitalization of Learning and Teaching, the main implication is that universities need to better prepare their teaching staff for digitalized education, especially if they are wanting to engage with disruption brought about by Industry 4.0.

Originality/value

The paper is based on a single university case study of a rather unique university within China. The discussion illustrates the need for flexibility and decisiveness in making key decisions on managing disruption, but with strategic direction in mind, illustrated in the study by COVID-19, but with future digitalization initiatives also to the fore.
An exploratory assessment of the educational practices during COVID-19
Authors: Kumar Vibhash , Verma Ashima
Published: September 2021

Purpose

This study aims to address the state of teaching-learning during the COVID-19 pandemic by assessing the pedagogies used, evidence collected, best practices used and technologies used for instruction by the academics in higher education institutions (HEIs). This study also analyses the impact of online academic motivation (OAM) and online academic amotivation of the teachers on the online student engagement (OSE) during the emergency remote teaching (ERT) period.

Design/methodology/approach

This study uses a mixed methodology by incorporating both qualitative and quantitative methods for analysis. Data used in this study have been drawn from a pool of educationists teaching in various HEIs in different parts of India (n= 900). Sentiment analysis, project map and mind map have been used to analyze the teachers’ experiences in the new teaching environment. Further, this study uses exploratory and confirmatory factor analysis and path analysis to measure and validate the study’s scales.

Findings

The combination of empirical and qualitative analysis captured the ERT model followed by the teachers. The overall experience of teachers regarding the online mode of teaching-learning is moderately positive. This study reports a direct positive and significant impact of teachers’ motivation on perceived student engagement in the online mode.

Originality/value

This research proposes and validates scales to measure perceived OSE and the teachers’ OAM. This study also establishes an impact assessment of the teachers’ motivation levels on the students’ engagement from an educator’s perspective.
On the manufacturability of Inconel 718 thin-walled honeycomb structures by laser powder bed fusion
Authors: Zea Pérez José M. , Corona-Castuera Jorge , Poblano-Salas Carlos , Henao John , Hernández Hernández Arturo
Published: September 2021

Purpose

The purpose of this paper is to study the effects of printing strategies and processing parameters on wall thickness, microhardness and compression strength of Inconel 718 superalloy thin-walled honeycomb lattice structures manufactured by laser powder bed fusion (L-PBF).

Design/methodology/approach

Two printing contour strategies were applied for producing thin-walled honeycomb lattice structures in which the laser power, contour path, scanning speed and beam offset were systematically modified. The specimens were analyzed by optical microscopy for dimensional accuracy. Vickers hardness and quasi-static uniaxial compression tests were performed on the specimens with the least difference between the design wall thickness and the as built one to evaluate their mechanical properties and compare them with the counterparts obtained by using standard print strategies.

Findings

The contour printing strategies and process parameters have a significant influence on reducing the fabrication time of thin-walled honeycomb lattice structures (up to 50%) and can lead to improve the manufacturability and dimensional accuracy. Also, an increase in the young modulus up to 0.8 times and improvement in the energy absorption up to 48% with respect to those produced by following a standard strategy was observed.

Originality/value

This study showed that printing contour strategies can be used for faster fabrication of thin-walled lattice honeycomb structures with similar mechanical properties than those obtained by using a default printing strategy.
Leveraging critical friendship to navigate doctoral student role transitions
Authors: Gregory Kristen Howell , Burbage Amanda Kate
Published: September 2021

Purpose

The purpose of this study is to investigate the influence of critical friendship on a first- and last-year doctoral student’s novice and expert mindsets during role transitions. Doctoral students are challenged to navigate role transitions during their academic programs. Experiences in research expectations, academy acculturation and work-life balance, may impact doctoral students’ novice-expert mindsets and contribute to the costly problem of attrition. Universities offer generic doctoral support, but few support sources address the long-term self-directed nature of self-study.

Design/methodology/approach

The authors participated in a collaborative self-study over a 30-month period. The authors collected 35 personal shared journal entries and 12 recorded and transcribed discussions. The authors conducted a constant comparative analysis of the data, and individually and collaboratively coded the data for initial and focused codes to construct themes.

Findings

The critical friendship provided a safe space to explore the doctoral experiences and novice-expert mindsets, which the authors were not fully able to do with programmatic support alone. The authors identified nine specific strategies that positively impacted the novice-expert mindsets during the following role transitions: professional to student, student to graduate and graduate to professional.

Originality/value

While researchers have identified strategies and models for doctoral student support targeting specific milestones, this study identified strategies to support doctoral students’ novice-expert mindsets during role transitions. These strategies may benefit other graduate students, as well as faculty and program directors, as they work to support student completion.
Promoting psychological well-being in doctoral students: a qualitative study adopting a positive psychology perspective
Authors: Jackman Patricia C. , Sisson Kelly
Published: September 2021

Purpose

Concerns about psychological well-being (PWB) in doctoral students have grown in recent years. The purpose of this study was to explore qualitatively doctoral students’ perceptions of factors that promoted their PWB during the doctoral journey.

Design/methodology/approach

Nine recent doctoral graduates at an English university participated in the study. Participants recalled their experience and PWB during the doctoral journey via a life grid and semi-structured interview. The life grids were visually inspected to identify high points in PWB whilst the interview data were analysed thematically.

Findings

The analysis produced the following seven themes representing factors that participants described during periods of better PWB: accomplishments; intrinsic rewards; self-efficacy; comprehension and understanding; supervisor support; wider support network; and self-care and lifestyle.

Originality/value

By adopting a positive psychology approach and exploring qualitatively factors that promoted PWB in doctoral students, this study offers an alternative perspective to research on doctoral student well-being, which has largely adopted a pathological focus. As such, the study demonstrates the utility of approaching research on doctoral students’ PWB from a positive psychology perspective. Findings are discussed in relation to the extant literature, and future directions for research are outlined.
Analyzing the cause of human electrical accidents using Swiss Cheese model
Authors: Puthillath Beena , Marath Bhasi , Ayappan Babu Chembakthuparambil
Published: September 2021

Purpose

This study aims to explore the factors influencing electrical accidents. Here, the authors aim to understand and model the causes of electrical accidents at multiple levels.

Design/methodology/approach

In the study, the authors have tried to put causes of accidents in the electricity distribution segment, in the framework of the Swiss Cheese model. Delphi kind of expert survey was conducted to find the Cheese Slice (level) and the causes (holes) for electrical accidents. Inputs from a hundred experts having more than five years of experience in electrical utility companies have been used to find Cheese Slice and holes, to explain the occurrence of an electrical accident.

Findings

Effective training for safe work practices, safe knowledge and closer supervision would go a long way to plug the holes in the Cheese Slice in human factors. The difference in perception of managers, supervisors and workers on the importance of various causes of electrical accidents are also presented and discussed.

Research limitations/implications

This research is based on expert opinion and survey where respondent perception is reported. Actual accident data has not been used here.

Practical implications

The holes or causes of accidents at different levels (Cheese Slice) have been identified for plugging or removal for better safety.

Social implications

Electrical energy is widely used, and therefore, electrical safety is a social concern and also improving it is a social need.

Originality/value

The study contributes to electrical safety issues in the electrical utility sector.
Proteomic profiling of extracellular vesicles and particles reveals the cellular response to cisplatin in NSCLC
Authors: Xu Jiaqi , Wang Lujuan , Yin Na , Chen Anqi , Yi Junqi , Tang Jingqun , Xiang Juanjuan
Published: September 2021

Background

Cisplatin‐based chemotherapy is a therapeutic strategy against non‐small cell lung cancer (NSCLC). However, cancers relapse after chemotherapy due to a dormant state of residual cancer cells. Extracellular vesicles and particles (EVPs) are active carriers of proteins and nucleic acid. Here, we aimed to study the molecular alterations and proteomic characteristics of EPV in dormant and reactivated cancer cells induced by cisplatin.

Methods

We used a short‐term single dose of cisplatin to induce the dormant and reactivated cell status. We examined the gene expressional profiling and proteomic profiling of EVPs from dormant and reactivated cancer cells by RNA‐sequencing and LC–MS/MS.

Results

We found substantial changes in gene expression and protein level in EVP. The genes with higher expression in dormant cancer cells were lipid transporter‐ and lipid metabolic‐related genes. A total of 111 EVP proteins were upregulated in dormant cancer cells compared to those in control cells. Fifty differential expressed proteins (DEPs) were identified in EVPs from reactivated cancer cells compared to those in dormant cancer cells. Among the DEPs, we found that apolipoproteins such as APOA1 and APOE were significantly increased in dormant cancer cell‐derived EVPs. Integration of EVP proteomes with transcriptional profiles of cancer cells revealed that the proteomic profiling of EVP derived from cancer cells can reflect the cellular status of cancer cells, which showed an activated lipid metabolism in dormant state.

Conclusion

Lipoproteins enriched in EVPs reflect the activated lipid metabolism in dormant cancer cells and may provide potential biomarkers or therapeutic targets for cisplatin‐based therapy.
Implementation and design of customized ex vivo machine perfusion. Analysis of its first results
Authors: Riveros Sergio , Marino Carlo , Ochoa Gabriela , Morales Emilio , Soto Dagoberto , Alegría Leyla , Zenteno María Josefina , Brañes Alejandro , Achurra Pablo , Rebolledo Rolando A.
Published: September 2021

The lack of organs available for transplantation is a global problem. The high mortality rates on the waiting list and the high number of discarded livers are reasons to develop new tools in the preservation and transplantation process. New tools should also be available for low‐income countries. This article reports the development of customized normothermic machine perfusion (NMP). An ex vivo dual perfusion machine was designed, composed of a common reservoir organ box (CRO), a centrifugal pump (portal system, low pressure), and a roller pump (arterial system, high pressure). Porcine livers (n = 5) were perfused with an oxygenated normothermic (37℃) strategy for 3 hours. Hemodynamic variables, metabolic parameters, and bile production during preservation were analyzed. Arterial and portal flow remain stable during perfusion. Total bilirubin production was 11.25 mL (4‐14.5) at 180 minutes. The median pH value reached 7.32 (7.25‐7.4) at 180 minutes. Lactate values decreased progressively to normalization at 120 minutes. This perfusion setup was stable and able to maintain the metabolic activity of a liver graft in a porcine animal model. Design and initial results from this customized NMP are promising for a future clinical application in low‐income countries.
Preclinical assessment of Class IV proximal contacts following different teaching strategies
Authors: Karl Elisabeta , Siddanna Geetha Duddanahalli , Mantesso Andrea
Published: September 2021

Introduction

Class IV composite restorations are one of the biggest challenges in dentistry. Furthermore, replacing adequate proximal contours on Class IV restorations is crucial for the function and aesthetics. The objective of this study is to assess four different teaching strategies used to improve first‐year dental students’ Class IV restoration proximal contact performance over a period of 4 years.

Materials and Methods

We assessed four cohorts of first‐year dental students who were exposed to four different teaching strategies during the first‐year preclinical training over two consecutive academic terms. The four different teaching strategies used were: (a) two waxing exercises (control cohort, strategy 1); (b) digital dentistry and four waxing exercises (strategy 2); (c) four waxing exercises (strategy 3); and (d) four waxing exercises and live demonstrations (strategy 4). All cohorts were exposed to the same didactic lecture of Class IV restorations.

Results

Our results showed that all teaching strategies resulted in better student's performance and content retention compared to the control cohort. However, the teaching strategy that resulted in the best pass/fail ratio was the association of waxing exercises with live demonstrations (strategy 4).

Discussion

Increasing the number of waxing exercises may improve students’ performance either alone or associated with different teaching strategies. However, when associated with live demonstrations, waxing exercises have significantly reduced critical errors.

Conclusions

Our study demonstrated for the first time the benefits of the affordable and traditional waxing exercises associated with instructor demonstrations as a teaching strategy for first‐year dental students.
Factors affecting the quality of online learning in a task‐based college course
Authors: Lee Sangmin‐Michelle
Published: September 2021

In the face of the COVID‐19 pandemic, all colleges in Korea were forced to transition to online teaching, as was the case in most of the rest of the world. This situation engendered confusion, frustration, and dissatisfaction among students as well as instructors. The present study examined college students' perceptions of online learning in general and of one purpose‐designed course in particular and compared their responses. The objective was to identify factors that might enhance the quality of online education (OE) and learner satisfaction. The present study applied a mixed method to ensure robust results, using a survey, interviews, students' reflection papers, and the instructor's field notes. The results indicated that the students perceived online learning as less effective than traditional face‐to‐face classes overall but were satisfied with the customized online course, specifically citing the instructor's prompt feedback, interaction among students, and effective design of tasks. Given this outcome, the present study suggests several pedagogical implications for OE in the future.
Study on cobweb‐like carbon nanotubes/calcium aluminate cement and its effect on the properties of Al2O3–SiC–C castables
Authors: Zang Yunfei , Xiao Guoqing , Ding Donghai , Chen Jianjun , Lei Changkun , Luo Jiyuan , Chong Xiaochuan
Published: September 2021

Cobweb‐like carbon nanotubes/calcium aluminate cement (CNTs/CAC) were synthesized through catalytic sintering with citric acid, calcium carbonate, and alumina as raw materials and ferric chloride as catalyst precursor. The products were characterized by X‐ray diffractometry, scanning electron microscopy, Raman spectroscopy, and high‐resolution transmission electron microscopy. The in situ cobweb‐like carbon firmly bonded between calcium aluminate grains, which endows the better oxidation resistance and water dispersion of carbon. The research had also shown that the bamboo‐like multiwalled carbon nanotubes with high aspect ratio were formed in cement by catalysis, which were entangled and aggregated to form cobweb‐like carbon. CNTs/CAC was applied in the Al2O3–SiC–C castables as a binder. Compared with the castables with spherical asphalt and in situ high‐content carbon‐containing calcium aluminate cement (HCCAC) as carbon source, the oxidation resistance index ratio of the castables bonded with CNTs/CAC increased by 45% and 22%, and the residual strength ratio increased by 25% and 20%, respectively. The results indicated that the oxidation resistance and thermal shock of the Al2O3–SiC–C castables bonded with CNTs/CAC were significantly improved.
Niobium carbide reinforced‐Ti6Al4V composites via directed energy deposition
Authors: Avila Jose D. , Bandyopadhyay Amit
Published: September 2021

Directed energy deposition (DED) was used to produce niobium carbide (NbC)‐reinforced Ti6Al4V (Ti64) metal–matrix‐composite (MMC) structures. The objective was to improve upon Ti64's wear and oxidation resistance. The characterization techniques consisted of scanning electron microscopy (SEM), backscattered electron (BSE) imaging, energy‐dispersive X‐ray spectroscopy (EDS), X‐ray diffraction analysis (XRD), thermogravimetric analysis (TGA), Vickers micro‐ and nanoindentation‐derived hardness, as well as tribological testing at varying normal loads. DED produced compositions were of Ti64, Ti64 + 5 wt.% NbC (5NbC), and Ti64 + 10 wt.% NbC (10NbC). Electron micrographs revealed crack‐ and delamination‐free structures. Tribological analysis revealed a 25.1% reduction in specific wear rate. XRD and EDS results indicated the presence of a Ti‐Nb solid solution. It was deduced that the NbC particles coupled with the Ti‐Nb solid solution aided in increasing Ti64's resistance to plastic shear as the superficial microstructure remained unchanged compared to pure Ti64. Additionally, TGA displayed a reduction in total oxidation mass gain and suppressed oxidation kinetics to parabolic behavior with increased NbC. Application‐based composite structures with site‐specific mechanical properties were fabricated in the form of a composite cylinder, gear and compositionally graded cylinder. The graded cylinder displayed a 0%–45%NbC presence—end‐to‐end—equating to a hardness increase from 161.6 ± 4.0HV0.2 to 1055.9 ± 157.4HV0.2.
Demographic expansion and high level of matrilineal diversity in two populations of East African Baggara cattle
Authors: Kambal Sumaya , Abdelrahim Amina E. , Hanotte Olivier , Nakao Ryo , Alkhaibari Abeer M. , Salim Bashir
Published: September 2021

Western Baggara cattle breed (WBCB) is an East African zebu inhabiting Sudan, well‐known as beef‐producing cattle. We investigated herein two phenotypically and geographically distinct populations of this breed, namely Nyalawi and Daeinawi, which are renowned for their unique meat production capabilities and adaptation attributes, with the aim to contribute to our understanding of their maternal genetic diversity and demography dynamics. Genetic polymorphism analysis of the full‐length D‐loop mtDNA region revealed 44 and 35 polymorphic sites defining 28 and 24 distinct haplotypes in the Nyalawi and the Daeinawi, respectively. Observed genetic diversity is high within the population with a low level of genetic differentiation between populations. Approximate Bayesian computation via the calculation of Bayesian skyline plots and neutrality tests support past expansion with a higher maternal effective population size (Ne) in Nyalawi compared with the Daeinawi population and a population expansion beginning around 4,500 YBP and 3,500 YBP, respectively, before the arrival of zebu into the continent.
Crypsis in the pelagic realm: evidence from exceptionally preserved fossil fish larvae from the Eocene Stolleklint Clay of Denmark
Authors: Heingård Miriam , Sjövall Peter , Sylvestersen René L. , Schultz Bo P. , Lindgren Johan
Published: September 2021

Marine deposits of earliest Eocene age in northern Jutland, Denmark, are renowned for yielding diverse teleost assemblages that have proved central for enhancing our understanding of the early evolution of many extant actinopterygian clades. In this study, we investigate diminutive larval fish fossils from the Stolleklint Clay, Ølst Formation, that retain multiple soft‐tissue features preserved as distinct dark‐coloured stains. To examine the elemental and molecular composition of these soft parts, we employed a combination of time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), scanning electron microscopy (SEM) and energy‐dispersive x‐ray spectroscopy (EDS). Our analyses revealed that the preserved structures contain chemically identifiable eumelanin intimately associated with densely aggregated microbodies that are morphologically consistent with melanosome organelles. Thus, we conclude that the carbonaceous structures represent traces of originally melanized body parts, including the eyes and peritoneum. Comparable pigmentation patterns are seen in many extant teleost larvae that use semi‐transparency as a means of camouflage in pelagic environments, to suggest a similar visual appearance of the Stolleklint Clay fish fossils. This in turn suggests that adaptations for concealment and UV‐protection had already evolved by the beginning of the Eocene, notably during a time interval characterized by an extreme greenhouse climate, when the global fish fauna become increasingly modern in composition.
Patient safety education for undergraduate nursing students: a scoping review protocol
Authors: Mugerwa Pumla P. , Jordan Portia , van der Heever Mariana , Young Taryn , Iwu-Jaja Chinwe Juliana
Published: September 2021

Objective:

The objective of the review is to examine the literature on patient safety and the teaching and learning strategies required to help students learn about patient safety in undergraduate nursing curricula in prelicensure nursing education programs.

Introduction:

Patient safety is a global concern, and health care professionals, including nurses who are on the frontline of health care delivery, should be equipped with the knowledge to enhance patient safety. Undergraduate nursing curricula should include the relevant patient safety content and supply nurse educators with teaching and learning strategies to help students acquire these skills.

Inclusion criteria:

Based on the Participants, Concept, and Context (PCC) framework, the eligible population will include nursing students who are enrolled in undergraduate nursing programs and nurse educators who teach in undergraduate nursing programs. The concept of interest is patient safety education, namely, the curricular content and teaching and learning strategies used to help nursing students learn the content. The context is prelicensure nursing education programs at college or university level. Eligible studies will include, but not be limited to, quantitative studies, observational, qualitative, and mixed-methods studies, systematic reviews, and opinion papers.

Methods:

Online databases will be searched across MEDLINE, CINAHL, and Web of Science. JBI methodology for scoping reviews will be used to conduct the review. Pre-determined inclusion and exclusion criteria will be used to select relevant studies. Data will be extracted and synthesized from studies that describe patient safety content and teaching and learning strategies in prelicensure nursing education.
Noise Reduction Analysis of Electronic Device Cooling Fan With Duct and Its Application Under Variable Working Conditions
Authors: Sun Zonghan , Tian Jie , Liśkiewicz Grzegorz , Du Zhaohui , Ouyang Hua
Published: September 2021

A noise reduction method for axial flow fans using a short inlet duct is proposed. The pattern of noise reduction imposed by the short inlet duct on the axial flow cooling fan under variable working conditions was experimentally and numerically examined. A 2-cm inlet duct was found to reduce tonal noise. As the tip Mach number of the fan increased from 0.049 to 0.156, the reduction in the total average sound pressure level at 1 m from the fan increased from 0.8 dB(A) to 4.3 dB(A), and further achieved 4.8 dB(A) when a 1-cm inlet duct was used. The steady computational fluid dynamics (CFD) showed that the inlet duct has little effect on the aerodynamic performance of the fan. The results of the full passage unsteady calculation at the maximum flow rate showed that the duct has a significant influence on the suction vortexes caused by the inlet flow nonuniformity. The suction vortexes move upstream to weaken the interaction with the rotor blades, which significantly reduces the pulsating pressure on the blades. The sound pressure level (SPL) at the blade passing frequency (BPF) contributed by the thrust force was calculated to reduce by 36 dB at a 135 deg observer angle, reflecting the rectification effect of the duct on the nonuniform inlet flow and the improvement in characteristics of the noise source. The proper orthogonal decomposition (POD) of the static pressure field on the blades verified that the main spatial mode is more uniformly distributed due to the duct, and energy owing to the rotor-inlet interaction decreases. A speed regulation strategy for the cooling fan with a short inlet duct is proposed, which guides the application of this noise reduction method.
Effect of Pad Material, Copper Versus Steel, on the Performance of a Tilting Pad Journal Bearing: Measurements and Predictions
Authors: San Andrés Luis , Kaizar Hussain , Jani Hardik , Thorat Manish
Published: September 2021

High-temperature operation limits the life of fluid film bearings; hence the need to quantify the effect of pad material on the performance of tilting pad journal bearings (TPJBs). The paper presents measurements of performance conducted on a copper-pads bearing (C-PB) and a steel-pads bearing (S-PB). Both bearings have the same geometry and differ on the pads' backing material, copper versus steel, and slightly in the assembled cold clearance. The journal diameter D = 102 mm, and a bearing has five pads with length L = 0.4D, nominal radial clearance 0.064 mm, and pad preload of 0.42. The pads are 12.3 mm in thickness and have a 50% offset pivot, ball-in-socket type. The bearings operate at four shaft speeds ranging from 6 krpm (32 m/s surface speed) to 14 krpm (74 m/s) and under multiple specific loads ranging from 0.17 MPa to 2.1 MPa. ISO VG 32 oil, at a supply temperature of 49 °C, lubricates a test bearing configured with end seals (flooded bearing). At the highest load (on pad) and low shaft speed, the S-PB static eccentricity is up to 37% higher than that for the C-PB. The oil exit temperature rise is similar for both bearings, the maximum difference reaches 6 °C. For all operating conditions, the pads' peak temperature rise, having a maximum difference of 5 °C–16 °C, is larger for the S-PB. The S-PB produces a ∼5% lower drag power loss than that in the C-PB. Drag power in both bearings increases with shaft speed and is largely independent of the applied load. From dynamic load tests with multiple excitation frequencies to 250 Hz, the C-PB direct stiffness KYY (along the load direction) is up to 30% higher than the S-PB stiffness, while the difference in KXX between the C-PB and the S-PB ranges from 60% to 90%. Similar to the stiffness results, the C-PB produces larger direct damping coefficients; CYY and CXX are up to 25% and 40% larger than those for the S-PB. Both bearings, however, show symmetry in the damping coefficients, i.e., CXX ∼ CYY. Virtual mass coefficients (MXX, MYY) are significant in magnitude though having a large uncertainty. A computational physics model predicts the TPJB performance under identical conditions. The exhaustive comparison conducted with a sound dimensional characterization of parameters reveals that predictions agree well with measurements of journal eccentricity, oil exit temperature, pad surface temperatures, and stiffness and damping force coefficients. The differences amount to 20% or less. The model relies on specifying the material properties for pads and pivots and the operating (hot) clearance to produce accurate thermomechanically induced deformations that affect bearing performance at high loads and high surface speed operation.
Doppler ultrasonographic evaluation of radial and ulnar artery diameters and blood flow, before and after percutaneous coronary interventions
Authors: Gündüz Yasemin , Gunduz Huseyin , Ates Omer Faruk , Ciner Mahmut , Cakmak Ahmetcan , Akcay. Cagla , Ilguz. Ersin , Cosansu Kahraman
Published: September 2021

Aim: Although the transforearm approach is considered a safe and effective option for percutaneous coronary intervention,
the different characteristics of the radial and ulnar arteries deserve attention. This study aimed to evaluate radial (RA) and ulnar artery (UA) diameter and blood ﬂow parameters changes after catheterization.
Material and method: A total of 328 patients were enrolled. Their artery (171 RA and 157 UA) diameter and flow parameters [peak systolic velocity (PSV), end-diastolic volume (EDV) and pulsatility index (PI)] were evaluated before and after catheterisation.
Results: After RA catheterization, the diameters and PSV decreased in the RA (from 2.71±0.66 to 2.47±0.51, p=0.007; from 44.7±8.3 to 33.9±9.5, p=0.021) and increased in the UA (from 2.49±0.83 to 2.59±0.58, p=0.033; from 48.3±11.9 to 59.6±11.0, p
Safety and parents´ acceptance of ultrasound contrast agents in children and adolescents – contrast enhanced voiding urosonography and contrast enhanced ultrasound
Authors: Seelbach Josefina , Krüger Paul C , Waginger Matthias , Renz Diane M , Mentzel Hans-Joachim
Published: September 2021

Aims: To evaluate the safety of the contrast enhanced voiding urosonography (ceVUS) and contrast enhanced ultrasound (CEUS) in children and adolescence and to receive data about parents’ acceptance of intravesical and intravenous application of sulfur hexafluoride.Material and methods: In this prospective, single centre study conducted over a 1 year study period, parents of 56 children (f/m=32/24; mean age 3.1 years; range 3 weeks - 15.9 years) with ceVUS and of 30 children (f/m=15/15; mean age 10.5 years; range 2 months - 17.7 years) with CEUS agreed to be included. A standardized telephone survey about the acceptance of the parents during and after the procedure as well as the adverse events (AE) were conducted within three days of the examination.Results: The parents would agree with the use of both ceVUS and CEUS as a diagnostic tool again in 96% (54/56) or 100% (30/30) of the cases, respectively and 92.9% (52/56) would prefer ceVUS to voiding cystourethrography (VCUG). In addition, 83.3% (25/30) would prefer CEUS to CT and 73.3% (22/30) would prefer CEUS to MRI. AE were reported in 3.6% after ceVUS (2/56; skin rash, mild fever) and in 3.3% after CEUS (1/30; vomiting). AE were subacute and self‑limited.Conclusions: The vast majority of parents prefer ceVUS and CEUS to VCUG, CT or MRI because of the safety profile of the contrast agent and diagnostic accuracy.
Value of ovarian positional assessment on 4D hysterosalpingo-contrast sonography
Authors: Zheng Wu-wu , Chen Lixia , Chen Shunping , Zhu Jian , Lin Feng , Xu Shihao
Published: September 2021

Aims: To investigate the positional relationship between the ovary and Fallopian tube and the relationship between the ovarian position and tubal morphology.Material and methods: A total of 195 patients with 338 fallopian tubes were enrolled in this retrospective study. The ovarian and tubal positions were defined relative to the uterus in all directions. Tubal morphology was classified as smooth or tortuous.Results: The distribution of the Fallopian tubes corresponded to the positions of the ipsilateral ovaries in the superoinferior direction (χ2 =197.653, p<0.001), mediolateral direction (χ2 =237.447, p <0.001) and anteroposterior direction (χ2 =109.746, p<0.001). Tubal morphology differed according to ovarian position in the superoinferior (χ2 =21.804, p<0.001), mediolateral directions (χ2 =4.679, p=0.031) but not in the anteroposterior direction (χ2 =0.793, p=0.373).Conclusions: Evaluating the ovarian position can provide preliminary information on the distribution and shapeof the Fallopian tube, helping the operator choose the appropriate initial plane and the necessary approaches for inspection.
Feasibility of pneumoperitoneum diagnosis using point-of-care ultrasound: a pilot study using a fresh cadaver model
Authors: Herbst Meghan Kelly , Carter Elizabeth M , Wu Shirley , Dietrich Christoph Frank , Hoffmann Beatrice
Published: September 2021

Aims: To assess the accuracy of point-of-care ultrasound (PoCUS) in the hands of two trained and blinded emergency physicians (EPs) in detecting very small amounts of free intraperitoneal air injected intra-abdominally, using a fresh human cadaver model.Material and methods: Fifteen cadavers were injected on 3 occasions with predefined quantities of free intraperitoneal air ranging from 0-10 mL. Seven cadavers were injected in the mid-epigastrium (ME), while 8 were injected in the left lower quadrant (LLQ). Each cadaver was scanned after each of the 3 injections by 2 trained and blinded EPs, resulting in 45 scans per sonographer. Scans were performed using previously validated and standardized techniques. All scans were recorded, time-stamped and labeled. For each scan the sonographers indicated “yes” or “no” to whether pneumoperitoneum was detected. A chi square analysis was performed to determine the sensitivity and specificity of PoCUS utilized by each sonographer of pneumoperitoneum based on the location and volume of air injected.Results: Free air (0.25-10 mL) injected into the ME was successfully diagnosed in 36/42 instances (86% sensitivity), but only detected in 10/36 instances when injected into the LLQ (28% sensitivity). Both EPs detected all air injections of ≥2 mL into the ME.Conclusion: Detection of free air originating from the midepigastric region may become a future PoCUS indication for adequately trained EPs.
The invasive intracoronary imaging assessment of left main coronary artery disease
Authors: Dregoesc Mihaela Ioana , Iancu Adrian Corneliu , Homorodean Călin
Published: September 2021

Left main coronary artery disease is associated with an unfavorable prognosis. Evidence-based decision making regarding the optimal revascularization strategy in patients with left main disease has become a challenge, in view of the recently published data. An improvement in outcomes following left main percutaneous interventions could be achieved by reducing the rate of repeat target lesion revascularization through stent optimization techniques. In the setting of left main disease, procedural guidance by intravascular ultrasound or optical coherence tomography is essential for good long-term results, in such a way that intravascular imaging has gained more of a therapeutic connotation. Besides stent optimization, intracoronary imaging quantifies lesion severity, guides lesion preparation through morphological data, facilitates stent selection through accurate vessel sizing, identifies the landing zones, diagnoses acute vessel wall complications such as stent-related edge dissection or intramural hematoma, and defines procedural success.This review focuses on the two main intracoronary imaging techniques used for diagnostic evaluation and procedural guidance in left main coronary artery disease: intravascular ultrasound and optical coherence tomography. Based on the most recently published data, the review discusses each technique’s advantages and pitfalls, and summarizes their indications.
The Clinical Relevance of the Accessory Peroneus Quartus in a Male Division I Collegiate Track Athlete
Authors: Robinson Nina , David Shannon L. , German Nicole A. , Swenson Jennifer
Published: September 2021

A healthy 20-year-old Division I track athlete participated in out-of-season practice and experienced inflammation on mid-lateral aspect of his right calcaneus. The patient modified his weekly training program, and a magnetic resonance imaging revealed the presence of an accessory peroneus quartus. This muscle is present in around 5.2% of the population. The pathological symptoms cause pain, snapping, and synovitis. Literature shows a higher prevalence of the accessory peroneus quartus muscle in males of European/American descent and in the right lower leg. Symptoms include peroneal tears, decrease in range of motion, and pain of the ankle and foot.
Maximal Strength in Relation to Force and Velocity Patterns During Countermovement Jumps
Authors: Haischer Michael H. , Krzyszkowski John , Roche Stuart , Kipp Kristof
Published: September 2021

Maximal strength is important for the performance of dynamic athletic activities, such as countermovement jumps (CMJ). Although measures of maximal strength appear related to discrete CMJ variables, such as peak ground reaction forces (GRF) and center-of-mass (COM) velocity, knowledge about the association between strength and the time series patterns during CMJ will help characterize changes that can be expected in dynamic movement with changes in maximal strength. Purpose: To investigate the associations between maximal strength and GRF and COM velocity patterns during CMJ. Methods: Nineteen female college lacrosse players performed 3 maximal-effort CMJs and isometric midthigh pull. GRF and COM velocity time series data from the CMJ were time normalized and used as inputs to principal-components analyses. Associations between isometric midthigh pull peak force and CMJ principal-component scores were investigated with a correlational analysis. Results: Isometric midthigh pull peak force was associated with several GRF and COM velocity patterns. Correlations indicated that stronger players exhibited a GRF pattern characterized by greater eccentric-phase rate of force development, greater peak GRF, and a unimodal GRF profile (P = .016). Furthermore, stronger athletes exhibited a COM velocity pattern characterized by higher velocities during the concentric phase (P = .004). Conclusions: Maximal strength is correlated to specific GRF and COM velocity patterns during CMJ in female college lacrosse athletes. Since maximal strength was not correlated with discrete CMJ variables, the patterns extracted via principal-components analyses may provide information that is more beneficial for performance coaches and researchers.
Training Session and Detraining Duration Affect Lower Limb Muscle Strength Maintenance in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis
Authors: Yang Yong , Chen Shu-Chen , Chen Chiao-Nan , Hsu Chihw-Wen , Zhou Wen-Sheng , Chien Kuei-Yu
Published: September 2021

Muscle strength after detraining is still higher than the level before training, which is an important issue for middle-aged and older adults. The purpose of the present study was to examine the effects of detraining duration (DD), resistance training duration (RTD), and intensity on the maintenance of resistance training (RT) benefits after detraining in middle-aged and older adults. A systematic search yielded 15 randomized control trails (n = 383) eligible for inclusion. The results showed that RTD ≥ 24 weeks and DD ≥ RTD, the RT benefits were still significantly maintained even with medium and low intensity (standardized mean difference = 1.16, 95% confidence interval, CI [0.38, 1.94], p = .004). When RTD < 24 weeks and DD ≤ RTD, only the high-intensity groups maintained the RT benefits (DD, 4–6 weeks: standardized mean difference = 0.71, 95% CI [0.34, 1.08], p = .0002; DD 8–16 weeks: standardized mean difference = 1.35, 95% CI [0.66, 2.04], p = .0001). However, when DD > RTD, the RT benefits were not maintained even with high intensity. In summary, when RTD was less than 24 weeks, RTD > DD was an important factor in maintaining muscle strength.
The Acute Effects of Fast-Paced Walking on Isometric Peak Torque and Rate of Torque Development in Regularly Exercising and Inactive Older Women
Authors: Palmer Ty B. , Blinch Jarrod , Farrow Ahalee C. , Agu-Udemba Chinonye C. , Mitchell Ethan A.
Published: September 2021

This study aimed to examine the acute effects of fast-paced walking on isometric peak torque and rate of torque development (RTD) in regular exercising and inactive older women. Ten regular exercising (67 ± 4 years) and 10 inactive (68 ± 4 years) older women performed three isometric knee extension contractions before and after a control condition (quiet resting) and an experimental condition of fast-paced walking for 6 min. Peak torque and early (RTD100), late (RTD200), and maximum (peak RTD) RTD measurements were obtained from each contraction. Results showed no significant changes in peak torque, peak RTD, or RTD200 after walking for either group (p > .050). A significant decrease in RTD100 was observed after walking for the inactive group (p = .005) but not for the regular exercisers (p = .909). These findings highlight the importance of physical activity and suggest that a task as simple as walking may impair the rapid strength capacities of inactive older women.