bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuity of supervision: Does it mean what we think it means?
Authors: Lee Ann S. , Ross Shelley
Published: September 2020

Context

Continuity of supervision (CoS) is generally accepted as an important element of competency‐based medical education (CBME). However, collecting and interpreting evidence for its effectiveness are a challenge because we lack a shared understanding of CoS. Translating the available evidence about CoS into practice is an even greater challenge because the evidence largely exists in the undergraduate medical education (UME) literature, whereas literature about CBME is mostly situated in postgraduate medical education (PGME).

Proposal

We explore the potential dangers of basing assumptions of the importance of CoS in CBME on evidence from the UME level where CBME is yet to be widely implemented. First, we discuss current understandings of what is meant by CoS and examine some of its evidence and where such evidence comes from. Next, we consider relevant theories related to CoS in the context of CBME and review how it is conceptualised in different educational models. We then discuss some contextual and pedagogical differences between UME and PGME when CoS is considered. Finally, we propose a shared understanding of CoS and outline implications and next steps to determine if the benefits of CoS seen at the UME level will also manifest with PGME learners.

Conclusions

We have the opportunity to undertake research to close our gap in knowledge about CoS at the PGME level using data emerging from our experiences with CBME. Selecting specific dimensions of CoS will allow research that is necessary to determine that what works at the UME level will also work at the PGME level as we continue to march towards CBME.
Interpretive description: A flexible qualitative methodology for medical education research
Authors: Thompson Burdine Julie , Thorne Sally , Sandhu Gurjit
Published: September 2020

Background

Qualitative research approaches are increasingly integrated into medical education research to answer relevant questions that quantitative methodologies cannot accommodate. However, researchers have found that traditional qualitative methodological approaches reflect the foundations and objectives of disciplines whose aims are recognizably different from the medical education domain of inquiry (Thorne, 2016, Interpretive description. New York, NY: Routledge). Interpretive description (ID), a widely used qualitative research method within nursing, offers an accessible and theoretically flexible approach to analysing qualitative data within medical education research. ID is an appropriate methodological alternative for medical education research, as it can address complex experiential questions while producing practical outcomes. It allows for the advancement of knowledge surrounding educational experience without sacrificing methodological integrity that long‐established qualitative approaches provide.

Purpose

In this paper, we present interpretive description as a useful research methodology for qualitative approaches within medical education. We then provide a toolkit for medical education researchers interested in incorporating interpretive description into their study design. We propose a coherent set of strategies for identifying analytical frameworks, sampling, data collection, analysis, rigour and the limitations of ID for medical education research. We conclude by advocating for the interpretive description approach as a viable and flexible methodology for medical education research.
RnhP is a plasmid‐borne RNase HI that contributes to genome maintenance in the ancestral strain Bacillus subtilis NCIB 3610
Authors: Nye Taylor M. , McLean Emma K. , Burrage Andrew M. , Dennison Devon D. , Kearns Daniel B. , Simmons Lyle A.
Published: September 2020

RNA‐DNA hybrids form throughout the chromosome during normal growth and under stress conditions. When left unresolved, RNA‐DNA hybrids can slow replication fork progression, cause DNA breaks, and increase mutagenesis. To remove hybrids, all organisms use ribonuclease H (RNase H) to specifically degrade the RNA portion. Here we show that, in addition to chromosomally encoded RNase HII and RNase HIII, Bacillus subtilis NCIB 3610 encodes a previously uncharacterized RNase HI protein, RnhP, on the endogenous plasmid pBS32. Like other RNase HI enzymes, RnhP incises Okazaki fragments, ribopatches, and a complementary RNA‐DNA hybrid. We show that while chromosomally encoded RNase HIII is required for pBS32 hyper‐replication, RnhP compensates for the loss of RNase HIII activity on the chromosome. Consequently, loss of RnhP and RNase HIII impairs bacterial growth. We show that the decreased growth rate can be explained by laggard replication fork progression near the terminus region of the right replichore, resulting in SOS induction and inhibition of cell division. We conclude that all three functional RNase H enzymes are present in B. subtilis NCIB 3610 and that the plasmid‐encoded RNase HI contributes to chromosome stability, while the chromosomally encoded RNase HIII is important for chromosome stability and plasmid hyper‐replication.
AvrE1 and HopR1 from Pseudomonas syringae pv. actinidiae are additively required for full virulence on kiwifruit
Authors: Jayaraman Jay , Yoon Minsoo , Applegate Emma R. , Stroud Erin A. , Templeton Matthew D.
Published: September 2020

Pseudomonas syringae pv. actinidiae ICMP 18884 biovar 3 (Psa3) produces necrotic lesions during infection of its kiwifruit host. Bacterial growth in planta and lesion formation are dependent upon a functional type III secretion system (T3S), which translocates multiple effector proteins into host cells. Associated with the T3S locus is the conserved effector locus (CEL), which has been characterized and shown to be essential for the full virulence in other P. syringae pathovars. Two effectors at the CEL, hopM1 and avrE1, as well as an avrE1‐related non‐CEL effector, hopR1, have been shown to be redundant in the model pathogen P. syringae pv. tomato DC3000 (Pto), a close relative of Psa. However, it is not known whether CEL‐related effectors are required for Psa pathogenicity. The Psa3 allele of hopM1, and its associated chaperone, shcM, have diverged significantly from their orthologs in Pto. Furthermore, the CEL effector hopAA1‐1, as well as a related non‐CEL effector, hopAA1‐2, have both been pseudogenized. We have shown that HopM1 does not contribute to Psa3 virulence due to a truncation in shcM, a truncation conserved in the Psa lineage, probably due to the need to evade HopM1‐triggered immunity in kiwifruit. We characterized the virulence contribution of CEL and related effectors in Psa3 and found that only avrE1 and hopR1, additively, are required for in planta growth and lesion production. This is unlike the redundancy described for these effectors in Pto and indicates that these two Psa3 genes are key determinants essential for kiwifruit bacterial canker disease.
Penicillium expansum: biology, omics, and management tools for a global postharvest pathogen causing blue mould of pome fruit
Authors: Luciano‐Rosario Dianiris , Keller Nancy P. , Jurick Wayne M.
Published: September 2020

Blue mould, caused primarily by Penicillium expansum, is a major threat to the global pome fruit industry, causing multimillion‐dollar losses annually. The blue mould fungus negatively affects fruit quality, thereby reducing fresh fruit consumption, and significantly contributes to food loss. P. expansum also produces an array of mycotoxins that are detrimental to human health. Management options are limited and the emergence of fungicide‐resistant Penicillium spp. makes disease management difficult, therefore new approaches and tools are needed to combat blue mould in storage. This species profile comprises a comprehensive literature review of this aggressive pathogen associated with pomes (apple, pear, quince), focusing on biology, mechanisms of disease, control, genomics, and the newest developments in disease management.

Taxonomy

Penicillium expansum Link 1809. Domain Eukaryota, Kingdom Fungi, Phylum Ascomycota, Subphylum Pezizomycotina, Class Eurotiomycetes, Subclass: Eurotiomycetidae, Order Eurotiales; Family Trichocomaceae, Genus Penicillium, Species expansum.

Biology

A wide host range necrotrophic postharvest pathogen that requires a wound (e.g., stem pull, punctures, bruises, shoulder cracks) or natural openings (e.g., lenticel, stem end, calyx sinus) to gain ingress and infect.

Toxins

Patulin, citrinin, chaetoglobosins, communesins, roquefortine C, expansolides A and B, ochratoxin A, penitrem A, rubratoxin B, and penicillic acid.

Host range

Primarily apples, European pear, Asian pear, medlar, and quince. Blue mould has also been reported on stone fruits (cherry, plum, peach), small fruits (grape, strawberry, kiwi), and hazel nut.

Disease symptoms

Blue mould initially appears as light tan to dark brown circular lesions with a defined margin between the decayed and healthy tissues. The decayed tissue is soft and watery, and blue‐green spore masses appear on the decayed area, starting at the infection site and radiating outward as the decayed area ages.

Disease control

Preharvest fungicides with postharvest activity and postharvest fungicides are primarily used to control decay. Orchard and packinghouse sanitation methods are also critical components of an integrated pest management strategy.

Useful websites

Penn State Tree Fruit Production Guide (https://extension.psu.edu/forage‐and‐food‐crops/fruit), Washington State Comprehensive Tree Fruit (http://treefruit.wsu.edu/crop‐protection/disease‐management/blue‐mold/), The Apple Rot Doctor (https://waynejurick.wixsite.com/applerotdr), penicillium expansum genome sequences and resources (https://www.ncbi.nlm.nih.gov/genome/browse/#!/eukaryotes/11336/).
Hippocampal subfield pathologic burden in Lewy body diseases vs. Alzheimer’s disease
Authors: Coughlin D. G. , Ittyerah R. , Peterson C. , Phillips J. S. , Miller S. , Rascovsky K. , Weintraub D. , Siderowf A. D. , Duda J. E. , Hurtig H. I. , Wolk D. A. , McMillan C. T. , Yushkevich P. A. , Grossman M. , Lee E. B. , Trojanowski J. Q. , Irwin D. J.
Published: September 2020

Aims

Lewy body diseases (LBD) are characterized by alpha‐synuclein (SYN) pathology, but comorbid Alzheimer’s disease (AD) pathology is common and the relationship between these pathologies in microanatomic hippocampal subfields is understudied. Here we use digital histological methods to test the association between hippocampal SYN pathology and the distribution of tau and amyloid‐beta (Aβ) pathology in LBD and contrast with AD subjects. We also correlate pathologic burden with antemortem episodic memory testing.

Methods

Hippocampal sections from 49 autopsy‐confirmed LBD cases, 30 with no/low AD copathology (LBD − AD) and 19 with moderate/severe AD copathology (LBD + AD), and 30 AD patients were stained for SYN, tau, and Aβ. Sections underwent digital histological analysis of subfield pathological burden which was correlated with antemortem memory testing.

Results

LBD − AD and LBD + AD had similar severity and distribution of SYN pathology (P > 0.05), CA2/3 being the most affected subfield (P < 0.02). In LBD, SYN correlated with tau across subfields (R = 0.49, P < 0.001). Tau burden was higher in AD than LBD + AD (P < 0.001), CA1/subiculum and entorhinal cortex (ERC) being most affected regions (P = 0.04 to <0.01). However, tau pathology in LBD − AD was greatest in CA2/3, which was equivalent to LBD + AD. Aβ severity and distribution was similar between LBD + AD and AD. Total hippocampal tau and CA2/3 tau was inversely correlated with memory performance in LBD (R = −0.52, −0.69, P = 0.04, 0.009).

Conclusions

Our findings suggest that tau burden in hippocampal subfields may map closely with the distribution of SYN pathology in subfield CA2/3 in LBD diverging from traditional AD and contribute to episodic memory dysfunction in LBD.
Accuracy of arrhythmia detection in implantable cardiac monitors: A prospective randomized clinical trial comparing Reveal LINQ and Confirm Rx
Authors: Ip John , Jaffe Brian , Castellani Mark , Sheikh Ali , Castellani Carson , Ip Randy
Published: September 2020

Background

Implantable cardiac monitors (ICMs) are increasingly used to detect arrhythmias in various clinical situations. However, the data transmission time and accuracy of detecting cardiac arrhythmias are unclear.

Objective

The objective of this study was to compare the efficiency of data transmission and arrhythmia detection accuracy of the Reveal LINQ with TruRhythm Detection with the Confirm Rx with SharpSense Technology.

Methods

In this prospective study, 142 patients were randomized 1:1 to receive Reveal LINQ or Confirm Rx ICM system. Arrhythmic events include atrial fibrillation (AF), pauses, and bradycardia. Data transmission time is defined as the time from event occurrence to physician notification. All the arrhythmic events are adjudicated for accuracy.

Results

A total of 3510 events were transmitted in 61 patients over 7.1 ± 3.5 months. The transmission time both for all events (448 ± 271 vs 610 ± 515 minutes, P = .02) and for patient activated triggers (24 ± 103 vs 475 ± 426 minutes, P < .0001) was significantly shorter in the Confirm Rx group. The total number of events was also higher in the Confirm Rx group (25.5 ± 45.6 vs 0.9 ± 1.1 events per patient‐month, P < .01), which is likely due to event transmission setting differences between the two groups. Kaplan‐Meier analysis showed that the Confirm Rx group detected true arrhythmic episodes sooner with higher percentage of diagnosed patients during 6‐month follow‐up (P = .006). Patient‐averaged true positive detection rates were not statistically significant in the two groups (Reveal LINQ vs Confirm Rx, AF: 52% vs 38%; bradycardia: 67% vs 59%; pause: 24% vs 20%; tachycardia: 81% vs 94%).

Conclusion

Compared to the Reveal LINQ, Confirm Rx has shorter event transmission time, more frequent event detections, shorter duration to diagnose true arrhythmic events, and higher percentage of diagnosed patients. The accuracy of arrhythmia detection in both ICMs remains suboptimal.
A network meta‐analysis on the efficacy and safety of monotherapies for tinea capitis, and an assessment of evidence quality
Authors: Gupta Aditya K. , Bamimore Mary A. , Renaud Helen J. , Shear Neil H. , Piguet Vincent
Published: September 2020

Various monotherapies exist for tinea capitis; however, their relative efficacies have never been determined using a statistical approach which compares treatments’ efficacy simultaneously. The goal of this study was to determine the relative efficacy (mycologic and complete cure rates) of monotherapies for the treatment of tinea capitis. On October 5, 2019, searches were performed in Scopus, PubMed, EMBASE, MEDLINE (Ovid), and CINAHL; there were no date restrictions. For the main network meta‐analysis, eligible studies were randomized trials that investigated the effect of tinea capitis monotherapies on subjects’ mycological and complete cure rates. Network meta‐analyses were conducted in accordance with the 2015 Preferred Reporting Items for Systematic Reviews and Meta‐Analyses checklist for network meta‐analyses. Mycological cure rate was the primary outcome; complete cure rate and adverse events were secondary outcomes. Twelve studies met the eligibility criteria for the main network; five systemic monotherapies were identified, griseofulvin, ketoconazole, terbinafine, itraconazole, and fluconazole. When the causative species was of the Microsporum genus, griseofulvin was most efficacious in terms of mycological cure (SUCRA = 66.1%) and complete cure (SUCRA = 80.6%). For tinea capitis caused by the Trichophyton species, terbinafine was the most efficacious in terms of both mycological and complete cure (SUCRA values of 75.2% and 78.2%, respectively). Risk of adverse events did not significantly differ across the interventions. Our results are congruent with those of previous pairwise meta‐analyses; our findings also corroborate clinical experience and anecdotal evidence.
Permissibility Is the Only Feasible Deontic Primitive
Authors: Gustafsson Johan E.
Published: September 2020

Moral obligation and permissibility are usually thought to be interdefinable. Following the pattern of the duality definitions of necessity and possibility, we have that something's being permissible could be defined as its not being obligatory to not do it. And that something's being obligatory could be defined as its not being permissible to not do it. In this paper, I argue that neither direction of this alleged interdefinability works. Roughly, the problem is that a claim that some act is obligatory or permissible entails that there is a moral law, whereas a negative claim that some act is not obligatory or not permissible does not. Nevertheless, one direction of the interdefinability can potentially be salvaged. I argue that, if we do not require the conceptual possibility of moral dilemmas, then there is a way to plausibly define obligation in terms of permissibility. I conclude that permissibility is the only feasible deontic primitive.
Rosmarinic acid improves boar sperm quality, antioxidant capacity and energy metabolism at 17°C via AMPK activation
Authors: Feng Tian‐Yu , Lv Dong‐Liang , Zhang Xing , Du Ye‐Qing , Yuan Yi‐Tian , Chen Mei‐Jie , Xi Hua‐Ming , Li Yu , Han Ning , Hu Jian‐Hong
Published: September 2020

Boar sperm are susceptible to oxidative damage caused by reactive oxygen species (ROS) during storage. Adenosine monophosphate (AMP)‐activated protein kinase (AMPK) is an important therapeutic target, because it is a cellular metabolism energy sensor and key signalling kinase in spermatozoa. We evaluated the effects of rosmarinic acid (RA), an antioxidant, on boar sperm during liquid storage to determine whether it protects boar sperm via AMPK activation. Boar ejaculates were diluted with Modena extender with different concentrations of RA and stored at 17°C for 9 days. Sperm quality parameters, antioxidant capacity, energy metabolism, AMPK phosphorylation and fertility were analysed. Compared with the control, 40 μmol/L significantly improved sperm motility, plasma membrane integrity and acrosome integrity (p < .05). The effective storage time of boar sperm was up to 9 days. On the third and seventh days, the sperm with RA exhibited increased total antioxidant capacity (T‐AOC), superoxide dismutase (SOD) activity, adenosine triphosphate (ATP) content, mitochondrial membrane potential (ΔΨm) and glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) activity, whereas malondialdehyde (MDA) content was significantly decreased (p < .05). Western blot showed that RA, as well as AICAR (AMPK activator), promoted AMPK phosphorylation, whereas Compound C (AMPK inhibitor) inhibited this effect. The sperm–zona pellucida binding experiment showed that 40 μmol/L RA increased the number of sperm attached to the zona pellucida (p < .05). These findings suggest meaningful methods for improved preservation of boar sperm in vitro and provide new insights into the mechanism by which RA protects sperm cells from oxidative damage via AMPK activation.
Purpose in life as a guiding framework for goal engagement and motivation
Authors: Lewis Nathan A.
Published: September 2020

One of the biggest challenges for research on goal pursuit and self‐regulation has been to understand factors that drive one's goals over the long‐term as well as day‐to‐day. Purpose in life, a component of psychological wellbeing has received increased interest in the health sciences for its ability to predict a myriad of health behaviours. The present work integrates the literature on purpose in life with goal organization and pursuit and posits that purpose in life represents a higher‐order cognitive process which reciprocally stimulates goal selection and long‐term goal maintenance and is itself promoted by such goal pursuits. Purpose in life may influence goal selection consciously through a top‐down hierarchy of goal pursuits as well as unconsciously through direction of nonconscious attentional processes. Goal pursuit may reciprocally promote feelings of purpose in life when individuals are able to continually make strides towards goals of personal relevance to their major life aims. This study aims to present a model of purpose in life and goal pursuit that will serve to guide future work in the fields of motivation, positive psychology, and health and lifespan development.
State‐NGOs relationship in the context of China contracting out social services
Authors: Mok Ka Ho , Chan Chak Kwan , Wen Zhuoyi
Published: September 2020

China's practice of contracting out social services raises two related questions. The first one seeks to determine “the contractual relationship” between the Chinese government and its third sector in a mixed welfare regime. The second one inquires whether China's commissioning welfare strategy has increased the power of its civil society. This study attempts to address these two issues based on the experiences of non‐governmental organisations (NGOs) in a Chinese city. It was found that the contracted NGOs were unable to obtain an equal status but were treated as assistants of local governments. The NGOs were also asked to do extra work that was not listed in the service contracts. Moreover, the service performance assessment criteria were unable to accurately evaluate the work of NGOs. Thus, the welfare participation of Chinese NGOs has not brought with them more political power. It is proposed that China's welfare reform needs to be backed up by its legal reform to put in place a mechanism that tackles the unequal power distribution between welfare purchasers and welfare providers. The study further illustrates that the Chinese government has adopted a pragmatic instrumentalism strategy by placing NGOs in a supplementary and subordinate role. This paper offers a conceptual discourse on analysing the state‐NGOs relationship against China's market reform and its search for a better welfare management strategy.
The sensor desert quandary: What does it mean (not) to count in the smart city?
Authors: Robinson Caitlin , Franklin Rachel S.
Published: September 2020

As a central component of the smart city, sensor infrastructures locate and measure a wide range of variables in order to characterise the urban environment. Perhaps the most visible expression of the smart city, sensor deployment is a key equity concern. As new sensor technologies and Big Data interact with social processes, they have the potential to reproduce well‐documented spatial injustices. Contrary to promises of providing new knowledge and data for cities, they can also create new gaps in understanding about specific urban populations that fall into the interstices of data collection – sensor deserts. Building on emerging data justice debates, specifically considering distributional, recognition, and procedural forms of injustice, we conceptualise and analyse sensor deserts through two case studies, Newcastle's Urban Observatory (UK) and Chicago's Array of Things (USA). Open sensor locations are integrated with small‐area, socio‐economic data to evidence the demographic configuration and spatialities of sensor deserts across each city. We illustrate how the structural processes via which inequality is reinforced by smart agendas manifest as uneven social and spatial outcomes. In doing so, the paper opens up a new conceptual space in which to consider what it means (not) to count in the smart city, bringing a demographic perspective to critical debates about smart urbanisms.
Options for ASEAN trade expansion: Within, plus three or six, European Union or the United States?
Authors: Beckman Jayson , Gopinath Munisamy , Daugherty Kamron
Published: September 2020

The ten member countries of the Association of Southeast Asian Nations (ASEAN) have pursued trade agreements with major trade partners (Plus Three—China, Japan and Korea; and Plus Six—Plus Three, Australia, New Zealand and India). The recent ASEAN move towards further economic integration suggests potential future agreements with other major trade partners. This study examines the economic opportunities for such expansion, focusing on several options for ASEAN: removing tariffs within the trading bloc, removing the remaining tariffs on trade with the six countries that they already have trade agreements with or more external options (agreements with either the EU or the US). We use a computable general equilibrium model (CGE) to examine these options, highlighting changes to both agriculture and non‐agriculture. Agriculture is the biggest beneficiary when considering an agreement with the EU or Plus Six, while non‐agriculture gains the most in an agreement with Plus Three or the US. Deeper integration through trade facilitation and realising technological spillovers increase welfare gains from select agreements.
Overexpression of Dnmt3a ameliorates diabetic muscle atrophy by modulating the Pten/Akt pathway
Authors: Wang Manfeng , Wu Xiaowei , Gan Lu , Teng Zongyan , Zhang Haijin , Zhang Yina
Published: September 2020

New Findings

What is the central question of this study?

Does Dnmt3a play a crucial role in regulating diabetic muscle atrophy?

What is the main finding and its importance?

Muscle atrophy is one of the major long‐term complications of diabetes mellitus. However, little is known about the molecular mechanism involved. In this paper, we demonstrated that Dnmt3a overexpression effectively improves the diabetic muscle health in mice and documented the underlying mechanisms. DNMT3A might become a promising target to prevent muscle atrophy in patients with diabetes.

Muscle atrophy is one of the major long‐term complications of diabetes mellitus, which greatly affects the mobility of patients. Epigenetic processes mediated by DNA methyltransferases (DNMTs) play crucial roles in the locomotor system, but little is known about the functions of DNMTs in diabetic muscle atrophy. Here, we investigated the function of Dnmt3a in diabetic muscle atrophy and explored the mechanisms involved. Adeno‐associated virus AAV2 overexpressing Dnmt3a or its vector control was injected into the tibialis anterior muscle of streptozotocin‐induced diabetic mice. Muscle mass and muscle cross‐sectional area were used to evaluate muscle atrophy. In vitro, adeno‐associated virus AAV2 overexpressing Dnmt3a or its vector control was transfected into C2C12 myoblasts. Horse serum was used to induce differentiation and palmitate to stimulate the C2C12 myoblasts. The expressions of myogenic regulatory factors were examined by real‐time PCR and western blot analysis. Overexpression of Dnmt3a attenuated muscle atrophy in diabetic mice and promoted myotube formation of C2C12 myoblasts. Overexpression of Dnmt3a restored the expressions of myogenic regulatory factors atrogin‐1, MuRF1, Pax7, Myod1 and myogenin, both in vivo and in vitro. Moreover, overexpression of Dnmt3a activated the phosphorylation of Akt by inhibiting the activation of Pten. This study demonstrates that overexpression of Dnmt3a prevents diabetic muscle atrophy by modulating the Pten/Akt pathway.
Sulfur and Nitrogen Release From Co-Pyrolysis of Coal and Biomass Under Oxidative and Non-Oxidative Conditions
Authors: Li Yukun , Li Lingfeng , Liu Yu , Ren Xiaohan , Chen Juan , Levendis Yiannis A.
Published: September 2020

This is an investigation on the effects of pyrolysis atmosphere on the conversion of biomass/coal blends to chars and volatile matter, and on the release of sulfur and nitrogen to the gas phase. Pulverized corn straw and lignite coal were co-pyrolyzed either in an inert carrier gas (N2) or in oxidative gases consisting of 3–7% O2 and 13–17% CO2 in a balance of 80% N2. The process occurred at temperatures in the range of 300–900 °C, under 1 atm, and lasted for 20 min. The results showed that the solid-phase conversion of coal/biomass blends ranged from 30 to 60%, increasing with increasing temperature. Increasing oxygen concentration under oxidative atmospheres promoted the solid-phase conversion at 500–900 °C, more than under the inert atmosphere, but had no discernible effect at lower temperatures (300–400 °C). Under the inert atmosphere, the co-pyrolysis of coal and biomass exhibited a synergistic effect, which promoted the transformation of solid feedstock into the gas phase or tar. To the contrary, under the oxidative atmospheres, the co-pyrolysis inhibited the evolution of volatile matter. Sulfur compounds, COS and SO2, were mainly released at temperatures in the range of 300–700 °C. Higher amounts of SO2 were released under the oxidative atmosphere, and the co-pyrolysis of coal and biomass promoted the release of COS. As for the transformation and release of nitrogen, NH3 and HCN were mainly released in the temperature range of 600–900 °C and more HCN was converted into NH3 under inert atmospheres. The effects of the oxygen content in the atmosphere on conventional gas species (CO, CH4, C2H6, and HCl) released from coal/biomass blends were also recorded.
Computational Modeling of Cardiac Ablation Incorporating Electrothermomechanical Interactions
Authors: Singh Sundeep , Melnik Roderick
Published: September 2020

The application of radio frequency ablation (RFA) has been widely explored in treating various types of cardiac arrhythmias. Computational modeling provides a safe and viable alternative to ex vivo and in vivo experimental studies for quantifying the effects of different variables efficiently and reliably, apart from providing a priori estimates of the ablation volume attained during cardiac ablation procedures. In this contribution, we report a fully coupled electrothermomechanical model for a more accurate prediction of the treatment outcomes during the radio frequency cardiac ablation. A numerical model comprising of cardiac tissue and the cardiac chamber has been developed in which an electrode has been inserted perpendicular to the cardiac tissue to simulate actual clinical procedures. Temperature-dependent heat capacity, electrical and thermal conductivities, and blood perfusion rate have been considered to model more realistic scenarios. The effects of blood flow and contact force of the electrode tip on the treatment outcomes of a fully coupled model of RFA have been systematically investigated. The numerical study demonstrates that the predicted ablation volume of RFA is significantly dependent on the blood flow rate in the cardiac chamber and also on the tissue deformation induced due to electrode insertion depth of 1.5 mm or higher.
A Comprehensive Flowrate Optimization Design for a Novel Air–Liquid Cooling Coupled Battery Thermal Management System
Authors: Chen Siqi , Wei Xuezhe , Garg Akhil , Gao Liang
Published: September 2020

Battery thermal management has significant effect on the performance of electric vehicles (EVs) under high current rates. In this research, a comprehensive thermal analysis and multi-objective optimization design framework is proposed to enhance the thermal performance of a novel air–liquid cooling coupled battery pack under higher discharging rate (3C). Computational fluid dynamics (CFD) numerical calculation is utilized to compare the cooling efficiency of the battery pack designs. Furthermore, a surrogate model is generated by using Latin hypercube sampling (LHS) and support vector machine. The design parameters include different mini-channels’ mass flowrates and the air flow inlet velocity, the objectives are the temperature rise, temperature distribution, and the energy consumption. Sensitivity analysis results indicate that the air flow inlet velocity is the main factor affecting the temperature rise and temperature distribution, while the mass flowrates of mini-channels have important influence on the pressure drop. Finally, the nondominated sorting genetic algorithm-II (NSGA-II) is used to select the optimal battery pack design, the maximum temperature, and temperature standard deviation (TSD) get improved by 1.8 K and 0.06 K, respectively. And the energy consumption of the cooling system can be controlled within the appropriate range after optimization design.
Analysis of Solar Power and Energy Variability Through Site Adaptation of Satellite Data With Quality Controlled Measured Solar Radiation Data
Authors: Bangarigadu Kaviraj , Hookoom Tavish , Ramgolam Yatindra Kumar , Kune Nadia Foo
Published: September 2020

Satellite-based solar power data is becoming more and more important because of its continuous temporal and spatial availability. However, its reliability can be enhanced through quality control and calibration against ground-based measurement data. Here, a holistic methodology is employed for the adaptation of satellite-based data for estimating solar energy. For the purpose, high-quality ground-based measurement data and satellite-based datasets are assessed across 12 sites in three small islands located in the Indian Ocean. Initially, both datasets go through a rigorous quality control process. A quantitative analysis of irradiance and insolation data is then conducted. Eventually, site adaptation of satellite-based data is performed using bias removal technique and statistical analysis of datasets. A set of seven statistical performance indicators is used to support the assessment. Analysis of datasets shows that adaptation of peak values should be performed separately. Results showed that despite the small surface areas of the islands studied, a spatial variation of insolation can be depicted. A temporal variation of insolation is also noted with a peak in the summer and low insolation levels in winter. Peak irradiance values tend to exceed solar constant for all sites. Variations of peak irradiance can only be noticed in ground-based measurement data. While insolation levels are comparable in the summer season for all the sites, insolation levels in the winter season are higher in the sites with lower latitudes. Calibration factors for peak irradiance, monthly and annual average irradiance as well as yearly insolation are presented.
Free Vibration of Bistable Clamped–Clamped Beams: Modeling and Experiment
Authors: Song Xiaolei , Liu Haijun
Published: September 2020

Bistable clamped–clamped beams have been used in a wide range of applications such as switches, resonators, energy harvesting, and vibration reduction. Most studies on this classic buckling problem focus on obtaining either the static configuration and the required critical axial load or the natural frequencies and mode shapes of postbuckling vibrations analytically. In this article, we present our study including analytical modeling and experimental method on bistable clamped–clamped beams, aiming to understand the detailed snap-through process and the ensuing vibration. In the analytical model, by decomposing the transverse deflection into static buckling configuration and linear vibration, we obtain the natural frequencies and mode shapes for the buckled beam and investigate the effects of static deflection on the symmetric and antisymmetric modes. An experimental design using noncontact methods is implemented to directly measure the response of the whole beam in the snap-through process and the sound generated by the vibrating beam. The measurements are characterized in both time and frequency domain and found to be in good agreement with the analytical model. The study presented in this article enhances the fundamental understanding of the classical problem of bistable clamped–clamped beams.
Three-Dimensional Solid Finite Element Contact Model for Rotordynamic Analysis: Experiment and Simulation
Authors: Oh Joseph , Kim Baik Jin , Palazzolo Alan
Published: September 2020

Conventional rotordynamic analyses generally treat the rotor as a continuous body without considering effect of clamped joints. However, in modern rotating machines, rotors are often assembled with multiple complex-shaped parts and joints, which may significantly affect rotordynamic behavior. Several authors have proposed methods for implementing contact effects in rotordynamic analysis, but a more general modeling method for handling arbitrary contact geometries with various levels of surface roughness is needed. The present paper suggests a new contact model for rotordynamic analysis of an assembled rotor-bearing system with multiple parts connected by multiple joints. A contact element formulation is presented using solid finite elements and statistics-based contact theories. A test arrangement was developed to validate the proposed contact model for varying interface surface roughness and preloads. An iterative computation algorithm is introduced to solve the implicit relation between contact stiffness and stress distribution. Prediction results, using the contact model, are compared with measured natural frequencies for multiple configurations of a test rotor assembly. A case study is performed for an overhung type rotor-bearing system to investigate the effect of contact interfaces, between an overhung impeller and a rotor shaft, on critical speeds.
Effective Mixed-Mode Ventilation System With Intermittent Personalized Ventilation for Improving Thermal Comfort in an Office Space
Authors: Katramiz Elvire , Ghaddar Nesreen , Ghali Kamel
Published: September 2020

The mixed-mode ventilation (MMV) system is an energy-friendly ventilation technique that combines natural ventilation (NV) with mechanical air conditioning (AC). It draws in fresh air when the outdoor conditions are favorable or activates otherwise the AC system during occupancy hours. To improve performance of the MMV system, it is proposed to integrate it with an intermittent personalized ventilation (IPV) system. IPV delivers cool clean air intermittently to the occupant and enhances occupant thermal comfort. With the proper ventilation control strategy, IPV can aid MMV by increasing NV mode operational hours, and improve the energy performance of the AC system by relaxing the required macroclimate set point temperature.

The aim of this work is to study the IPV+MMV system performance for an office space application in terms of thermal comfort and energy savings through the implementation of an appropriate control strategy. A validated computational fluid dynamics (CFD) model of an office space equipped with IPV is used to assess the thermal fields in the vicinity of an occupant. It is then coupled with a transient bio-heat and comfort models to find the overall thermal comfort levels. Subsequently, a building-performance simulation study is performed using Integrated Environmental Solutions-Virtual Environment (IES-VE) for an office in Beirut, Lebanon for the typical summer month of July. An energy analysis is conducted to predict the savings of the suggested design in comparison to the conventional AC system. Results showed that the use of IPV units and MMV significantly reduced the number of AC operation hours while providing thermal comfort.
Numerical Simulation of Heat Conduction Problems With the Lattice Boltzmann Method (LBM) and Discrete Boltzmann Method (DBM): A Comparative Study
Authors: Chen Leitao , Petrosius Timothy , Schaefer Laura
Published: September 2020

Unlike Fourier’s law, which is built upon the continuum assumption and constitutive equation of energy conservation, kinetic models study the transport phenomena from a more fundamental level and in a more generalized way. The Boltzmann equation (BE), which is one type of kinetic model, is a generalized transport model that can solve any advection-diffusion problem regardless of whether such a problem is advection-dominated or diffusion-dominated. Although the BE has been successfully applied to model fluid transport, which is an advection-dominated process, in this paper, in order to demonstrate the generality of the BE, heat conduction, which is a diffusion-only process, is simulated by two numerical derivatives of the BE: the lattice Boltzmann method (LBM) and the discrete Boltzmann method (DBM). The DBM model presented in this paper is unique in the way that the BE is solved on complete unstructured grids with the finite volume method. Therefore, it is named the finite volume discrete Boltzmann method (FVDBM). Two two-dimensional heat conduction problems with different domain geometries and boundary conditions are simulated by both the LBM and FVDBM and quantitatively compared. From that comparison, it is found that the FVDBM produces a higher level of accuracy than the LBM for problems with curved boundaries, while maintaining the same accuracy as the LBM for problems with straight boundaries. The advantage displayed by the FVDBM approach is the direct result of a more accurate reconstruction of curved boundaries by the utilization of unstructured grids, versus the Cartesian grids necessary for the LBM.
Experimental Investigation of Shell-Side Flow Condensation on Three-Dimensional Enhanced Surface Tubes
Authors: Yang Desong , Sun Zhichuan , Li Wei
Published: September 2020

An experimental investigation of shell-side flow condensation heat transfer was performed on advanced three-dimensional surface-enhanced tubes, including a herringbone micro-fin tube and a newly-developed 1-EHT tube. An equivalent plain tube was also tested for performance comparison. All of the test tubes have similar geometry parameters (inner diameter 11.43mm, outer diameter 12.7mm). Tests were conducted using R410A as the working fluid at a condensation saturation temperature of 45 °C, covering the mass flux range of 10–55 kg/(m2·s) with an inlet quality of 0.8 and an outlet quality of 0.1. Experimental results showed that the plain tube exhibits a better condensation heat transfer performance when compared to the enhanced tubes. Moreover, the mass flux has a significant influence on the heat transfer coefficient for shell-side condensation: the condensation heat transfer coefficient of plain tube decreases when the refrigerant mass flux becomes larger, while the heat transfer coefficient of herringbone tube shows a non-monotonic trend and the heat transfer coefficient of the 1-EHT tube gets higher with increasing refrigerant mass flux. Besides, A new prediction model based on the Cavallini’s equation was developed to predict the condensing coefficient of the three test tubes, and the mean absolute error of the improved equations is less than 4%.
Condensation Heat Transfer and Pressure Drop of R134A in Horizontal Micro-Scale Enhanced Tube
Authors: Gu Zongbao , Ma Xiang , He Yan , Ma Lianxiang , Kukulka David J. , Li Wei
Published: September 2020

This study was performed to investigate the heat transfer and pressure drop of R134A during condensation inside a stainless steel micro-scale enhanced surface tube (EHT tube) and smooth tube. The tests were conducted at a saturation temperature of 45°C, over the mass fluxes range of 100 to 200 kg/m2s, the heat fluxes of 14–25 kW/m2, an inlet vapor quality of 0.8 and outlet vapor quality of 0.2. The heat length and inner diameter of the tested tube were 2 m and 11.5 mm. The micro-scale enhanced surface tube has complex surface structures composed of dimples and petal arrays background patterns. It can be observed the condensation heat transfer coefficients of the EHT tube is about 1.6–1.7 times higher than that of a stainless steel smooth tube. Enhancement of the EHT tube was achieved due to disruption of the boundary layer, secondary fluid generation, increasing fluid turbulence and heat transfer area. In addition, considering the friction pressure drop, the EHT tube produces the larger friction pressure drop, which is 1.05–1.20 times as compared to the smooth tube. Finally, the performance factors were performed to evaluate the enhancement effect of the EHT tube based on heat transfer coefficient-pressure drop evaluation criteria value (η1) and heat transfer coefficient-area evaluation criteria value (η2).
Application of Scatter Search With Path Relinking for Scheduling Problems With Crane Interference
Authors: Tanizaki Takashi , Masuda Yuto , Katagiri Hideki
Published: September 2020

Scheduling problems in manufacturing are large and complex, and there are many constraints. Therefore, it is difficult to obtain the optimal solution within a practical time. If it is necessary to avoid interference between cranes in addition to not violating the operational constraints of each machine, it is difficult to obtain the optimal solution to such scheduling problems in a practical time. For this scheduling problem, we propose a new solution algorithm combining scatter search with path relinking and operation simulation. In this paper, we describe previous research, our target process, the new solution algorithm, and discuss algorithm design methods based on numerical experiments.
Review on recent progress in patterning phase change materials
Authors: Shen Meihua , Lill Thorsten , Altieri Nick , Hoang John , Chiou Steven , Sims Jim , McKerrow Andrew , Dylewicz Rafal , Chen Ernest , Razavi Hamid , Chang Jane P.
Published: September 2020

This review discusses critical aspects of patterning phase change materials (PCMs), including dry etching, wet clean, and encapsulation, as they dictate the reliability and functionality of the phase change random access memory devices. Specifically, alloys of germanium–antimony–tellurium are used as a model system, and the importance of PCM composition control, critical dimension control, high fidelity pattern transfer, and a system level of ambient control to avoid oxidation that can alter the materials’ functionality are highlighted. The research findings motivate the development of a state-of-the-art integrated system that combines dry etch, wet clean, and encapsulation into one platform to realize consistent and successful patterning of PCMs for future generations of the memory devices.
Experimental characterization of high-intensity focused airborne ultrasound fields
Authors: Liebler Marko , Kling Christoph , Gerlach André , Koch Christian
Published: September 2020

High-intensity focused airborne ultrasound fields are increasingly applied in various technical fields, for example, to generate haptic feedback during gesture interaction. Reliable measurement data of sound pressure levels are required to assess potential health hazards to users. Such ultrasound fields pose special challenges for a quantitative characterization. The high sound pressure levels in combination with the higher harmonics generated by nonlinear effects require both a high upper limit of the level linearity range and a wide bandwidth of the measuring chain. Furthermore, small wavelengths and the focusing result in spatially strongly varying sound fields. In the present case, a 40 kHz signal was focused on a single point using a transducer array. Different microphone types were investigated with respect to their suitability for measuring high-power airborne ultrasound fields. A spatial characterization of the ultrasound field in the focal region as well as around an artificial head in a simulated application situation was performed. The microphone measurements were supplemented by measuring the radiation force with a balance and were compared to an analytical model of the sound field distribution. The presented results can contribute to the improvement of measurement technology and support a first assessment of the exposure of potential users.