bluuebunny/crossref_metadata_2025 huggingface dataset:
Resource availability and disturbance shape maximum tree height across the Amazon
Authors: Gorgens Eric B. , Nunes Matheus H. , Jackson Tobias , Coomes David , Keller Michael , Reis Cristiano R. , Valbuena Ruben , Rosette Jacqueline , de Almeida Danilo R. A. , Gimenez Bruno , Cantinho Roberta , Motta Alline Z. , Assis Mauro , de Souza Pereira Francisca R. , Spanner Gustavo , Higuchi Niro , Ometto Jean Pierre
Published: October 2020

Tall trees are key drivers of ecosystem processes in tropical forest, but the controls on the distribution of the very tallest trees remain poorly understood. The recent discovery of grove of giant trees over 80 meters tall in the Amazon forest requires a reevaluation of current thinking. We used high‐resolution airborne laser surveys to measure canopy height across 282,750 ha of old‐growth and second‐growth forests randomly sampling the entire Brazilian Amazon. We investigated how resources and disturbances shape the maximum height distribution across the Brazilian Amazon through the relations between the occurrence of giant trees and environmental factors. Common drivers of height development are fundamentally different from those influencing the occurrence of giant trees. We found that changes in wind and light availability drive giant tree distribution as much as precipitation and temperature, together shaping the forest structure of the Brazilian Amazon. The location of giant trees should be carefully considered by policymakers when identifying important hot spots for the conservation of biodiversity in the Amazon.
Genomic landscape of reproductive isolation in Lucania killifish: The role of sex loci and salinity
Authors: Berdan Emma L. , Fuller Rebecca C. , Kozak Genevieve M.
Published: October 2020

Adaptation to different environments can directly and indirectly generate reproductive isolation between species. Bluefin killifish (Lucania goodei) and rainwater killifish (L. parva) are sister species that have diverged across a salinity gradient and are reproductively isolated by habitat, behavioural, extrinsic and intrinsic post‐zygotic isolation. We asked if salinity adaptation contributes indirectly to other forms of reproductive isolation via linked selection and hypothesized that low recombination regions, such as sex chromosomes or chromosomal rearrangements, might facilitate this process. We conducted QTL mapping in backcrosses between L. parva and L. goodei to explore the genetic architecture of salinity tolerance, behavioural isolation and intrinsic isolation. We mapped traits relative to a chromosome that has undergone a centric fusion in L. parva (relative to L. goodei). We found that the sex locus appears to be male determining (XX‐XY), was located on the fused chromosome and was implicated in intrinsic isolation. QTL associated with salinity tolerance were spread across the genome and did not overly co‐localize with regions associated with behavioural or intrinsic isolation. This preliminary analysis of the genetic architecture of reproductive isolation between Lucania species does not support the hypothesis that divergent natural selection for salinity tolerance led to behavioural and intrinsic isolation as a by‐product. Combined with previous studies in this system, our work suggests that adaptation as a function of salinity contributes to habitat isolation and that reinforcement may have contributed to the evolution of behavioural isolation instead, possibly facilitated by linkage between behavioural isolation and intrinsic isolation loci on the fused chromosome.
Comparative study of intralesional tuberculin protein purified derivative (PPD) and intralesional measles, mumps, rubella (MMR) vaccine for multiple resistant warts
Authors: Mohammed Yaser F. , Ibrahim Hany S. , Elbarbary Marwa A. , Elsaie Mohamed L.
Published: October 2020

Background

Cutaneous warts are frequent conditions that possess much challenge to treat.

Objective

To evaluate safety and efficacy of intralesional injection of tuberculin purified protein derivative (PPD) antigen injection vs MMR (mumps, measles, rubella) antigen for the treatment of multiple warts.

Methods

The study included 90 Patients who were divided into three groups (A, B, and C). Each group consisted of (30) patients. Group (A) subjects received intralesional PPD injections. Group (B) subjects received intralesional MMR antigen injection and Group (C) received intralesional saline injection.

Results

Full clearance of warts was observed in 18 (60%) of patients in group (A) (70%) vs 24 patients (80%) in group (B). Distal warts completely disappeared in 18 (60%) of patients in group A and 12 (40%) of patients in group B. Infrequent side effects including pain, erythema, and minimal induration were reported in both groups.

Conclusion

We established a good safety and efficacy profile for tuberculin PPD and MMR antigens in resistant wart treatment.
Exploring parents' provision of factors related to the establishment of physical activity between normal weight and overweight infants
Authors: Dinkel Danae , Rech John P. , Snyder Kailey
Published: October 2020

Purpose

Infancy is a critical time for the prevention of obesity and establishment of healthy behaviors such as physical activity that help to control weight. A limited amount of research has examined if factors related to infant physical activity vary by infant weight status. Therefore, the purpose of this mixed methods triangulation study was to examine differences in motor development, the home environment, and infant‐parent play behaviors as well as to explore how parents promote active play opportunities with normal weight infants (NWIs) and overweight infants (OWIs).

Design and Methods

We used a mixed methods triangulated approach to combine quantitative and qualitative data strands to examine variables associated with active play in normal weight (n = 16) and overweight (n = 11) infants. Data were analyzed using a two‐tailed Mann–Whitney U nonparametric test and a summative content analysis approach.

Results

Although there were no differences in infants' motor development and parent play behaviors based on infant weight, several other differences were found. OWIs had less access to materials that stimulate locomotor movement. Further, parents of OWIs more often reported utilizing cognitive play strategies in comparison to parents of NWIs who more often reported using physical play strategies. Parents felt they were the greatest influence on their child's activity regardless of infant size. Importantly, all parents desired more specific guidelines on how to encourage active play and preferred this information was delivered by their healthcare provider.

Practice Implications

To meet parents' desires and potentially improve infants' developmental outcomes through the establishment of healthy physical activity behaviors, pediatric nurses could provide more specific guidance on providing active opportunities for infants.
Fashion designs and brands: The role of the informed user and the average consumer
Authors: Frabboni Maria Mercedes
Published: October 2020

The notions of the informed user and average consumer occupy centre stage in design and trade marks disputes. The current European Union legal framework exposes a tension between these notions as legal constructs informed by normative objectives, and the need to connect them with the business reality of design and trade mark practice. This article investigates how litigation concerning fashion design and brands addresses this tension and shapes the definition and application of legal tests for the informed user and the average consumer. It analyses key criteria that determine who these notional persons are, and how those criteria are applied when performing assessments that combine abstract legal standards with information acquired from the experience that real users and consumers make of fashion designs and brands.
Identification of intraneuronal amyloid beta oligomers in locus coeruleus neurons of Alzheimer’s patients and their potential impact on inhibitory neurotransmitter receptors and neuronal excitability
Authors: Kelly Louise , Seifi Mohsen , Ma Ruolin , Mitchell Scott J. , Rudolph Uwe , Viola Kirsten L. , Klein William L. , Lambert Jeremy J. , Swinny Jerome D.
Published: October 2020

Aims

Amyloid β‐oligomers (AβO) are potent modulators of Alzheimer's pathology, yet their impact on one of the earliest brain regions to exhibit signs of the condition, the locus coeruleus (LC), remains to be determined. Of particular importance is whether AβO impact the spontaneous excitability of LC neurons. This parameter determines brain‐wide noradrenaline (NA) release, and thus NA‐mediated brain functions, including cognition, emotion and immune function, which are all compromised in Alzheimer's patients. Therefore, the aim of the study was to determine the expression profile of AβO in the LC of Alzheimer's patients and to probe their potential impact on the molecular and functional correlates of LC excitability, using a mouse model of increased Aβ production (APP‐PSEN1).

Methods and results

Immunohistochemistry and confocal microscopy, using AβO‐specific antibodies, confirmed LC AβO expression both intraneuronally and extracellularly in both Alzheimer's and APP‐PSEN1 samples. Patch clamp electrophysiology recordings revealed that APP‐PSEN1 LC neuronal hyperexcitability accompanied this AβO expression profile, arising from a diminished inhibitory effect of GABA due to impaired expression and function of the GABA‐A receptor (GABAAR) α3 subunit. This altered LC α3‐GABAAR expression profile overlapped with AβO expression in samples from both APP‐PSEN1 mice and Alzheimer's patients. Finally, strychnine‐sensitive glycine receptors (GlyRs) remained resilient to Aβ‐induced changes and their activation reversed LC hyperexcitability.

Conclusions

The data suggest a close association between AβO and α3‐GABAARs in the LC of Alzheimer's patients, and their potential to dysregulate LC activity, thereby contributing to the spectrum of pathology of the LC‐NA system in this condition.
Interannual variability of ecosystem iso/anisohydry is regulated by environmental dryness
Authors: Wu Genghong , Guan Kaiyu , Li Yan , Novick Kimberly A. , Feng Xue , McDowell Nate G. , Konings Alexandra G. , Thompson Sally E. , Kimball John S. , De Kauwe Martin G. , Ainsworth Elizabeth A. , Jiang Chongya
Published: October 2020

Plants are characterized by the iso/anisohydry continuum depending on how they regulate leaf water potential (ΨL). However, how iso/anisohydry changes over time in response to year‐to‐year variations in environmental dryness and how such responses vary across different regions remains poorly characterized.

We investigated how dryness, represented by aridity index, affects the interannual variability of ecosystem iso/anisohydry at the regional scale, estimated using satellite microwave vegetation optical depth (VOD) observations. This ecosystem‐level analysis was further complemented with published field observations of species‐level ΨL.

We found different behaviors in the directionality and sensitivity of isohydricity (σ) with respect to the interannual variation of dryness in different ecosystems. These behaviors can largely be differentiated by the average dryness of the ecosystem itself: in mesic ecosystems, σ decreases in drier years with a higher sensitivity to dryness; in xeric ecosystems, σ increases in drier years with a lower sensitivity to dryness. These results were supported by the species‐level synthesis.

Our study suggests that how plants adjust their water use across years – as revealed by their interannual variability in isohydricity – depends on the dryness of plants’ living environment. This finding advances our understanding of plant responses to drought at regional scales.
Acanthamoeba keratitis: a review of biology, pathophysiology and epidemiology
Authors: de Lacerda Ana Gomes , Lira Madalena
Published: October 2020

Acanthamoeba keratitis is an infection caused by a unicellular protozoan of the genus Acanthamoeba that is universally widespread. Until now, most cases were reported in contact lens wearers, although it is also a reality for non‐wearers, mostly connected to corneal trauma. There is also a variation in incidence regarding the aetiology of the disease between developed and developing countries.

Purpose

This work is based on a literature review, and the main goal is to deepen the knowledge about Acanthamoeba keratitis, presenting the main risk factors and focusing on prevention actions for this type of corneal infection since the treatments are not always effective. It targets specialists in visual health to strengthen their knowledge in this area, as well as to allow them to better inform their patients about hygiene care, appropriate measures of disinfection and ways to minimise the risk of infection. At this stage, it is important to highlight the essential role that practitioners play in fitting, monitoring and following‐up patients to minimise the danger of infection.

Recent findings

It is well recognised that corneal trauma facilitates invasion by leaving an open door for microorganisms to penetrate the cornea. In addition to trauma, risk factors are mostly associated with patients’ behaviours, such as interaction of contact lenses with contaminated water in the shower, swimming pools and beaches, etc., lack of hygiene habits with contact lenses and respective cases, and the use of ineffective disinfecting solutions. The fact that a disinfecting solution is not completely effective against trophozoites and/or cysts, both forms of Acanthamoeba’s lifecycle, can cause the infection since one cyst alone leads to the emergence of a whole new population of Acanthamoeba.

It is necessary to reduce the risk of infection and, beyond the need to promote patient education to encourage correct CL hygiene behaviours, it should also be highlighted that there is an urgent need to enhance the efficacy of CL disinfection systems against all strains and both stages of Acanthamoeba through the creation of standardised methods. The ease of purchasing CLs without any supervision must also be considered a concern, and, in the near future, it is also important to develop and implement effective diagnostic methods and treatments for Acanthamoeba keratitis.
Anatomy of the cardiac conduction system
Authors: Padala Santosh K. , Cabrera José‐Angel , Ellenbogen Kenneth A.
Published: October 2020

The specialized cardiomyocytes that constitute the conduction system in the human heart, initiate the electric impulse and result in rhythmic and synchronized contraction of the atria and ventricles. Although the atrioventricular (AV) conduction axis was described more than a century ago by Sunao Tawara, the anatomic pathway for propagation of impulse from atria to the ventricles has been a topic of debate for years. Over the past 2 decades, there has been a resurgence of conduction system pacing (CSP) by implanting pacing leads in the His bundle region in lieu of chronic right ventricular pacing that is associated with worse clinical outcomes. The inherent limitations of implanting the leads in the His bundle region has led to the emergence of left bundle branch area pacing in the past 3 years as an alternative strategy for CSP. The clinical experience from performing CSP has helped electrophysiologists gain deeper insight into the anatomy and physiology of cardiac conduction system. This review details the anatomy of the cardiac conduction system, and highlights some of the recently published articles that aid in better understanding of the AV conduction axis and its variations, the knowledge of which is critical for CSP. The remarkable evolution in technology has led to visualization of the cardiac conduction system using noninvasive, nondestructive high‐resolution contrast‐enhanced micro‐computed tomography imaging that may aid in future CSP. We also discuss from anatomical perspective, the differences seen clinically with His bundle pacing and left bundle branch area pacing.
Risk factors associated with cognitive impairment in patients after pediatric liver transplantation
Authors: Eder Beatrix , Melter Michael , Gabler Vanessa , Zant Robert , Knoppke Birgit
Published: October 2020

Data on cognitive function after pLT are rare, particularly regarding children with cognitive impairment. From 2016 to 2018, we evaluated cognitive function in 36 patients after pLT aged 6‐17 years with the WISC IV (at least 1 year after transplantation) and analyzed potential risk factors for cognitive impairment (IQ < 70) by means of retrospective medical data (peri‐, intra‐, and post‐operative factors, and donor and specific organ data of the primary liver transplant) on an exploratory base. At a median age of 9.6 years (range = 6‐16.9), 22% of patients were cognitive impaired (IQ < 70; including five untestable patients with severe cognitive impairment). Children tested with the WISC IV scored within the lower normal range but differed significantly from normal population. Strongest associations showed infections at pLT, development of severe sepsis requiring intensive care within the first 6 months after pLT, neurological complications within the first 10 days and the occurrence of CPR during or after pLT, and as early laboratory variables pH value on day 0 after pLT. In our analysis, neither intraoperative factors nor donor‐specific factors seemed to influence cognitive outcome. In our small cohort, medical complications before and after pLT but not transplantation itself had an influence on cognitive outcome. As such, children experiencing medical problems before and in the early post‐operative phase after pLT should be closely evaluated in larger samples regarding their neurological and psychomotor development during vulnerable phases and should receive early educational support to improve long‐term cognitive function.
Why does only one embryo sac develop in the Paeonia ovule with multiple archesporium?
Authors: Vinogradova G. Yu. , Zhinkina N. A.
Published: October 2020

Structure of the multiple archesporium in an ovule, time and place of archesporial cell differentiation and their developmental potential have not been studied in detail. In Paeonia species supernumerary archesporial cells are formed and differentiate as multiple megasporocytes, but only one embryo sac usually develops into an ovule. The reasons leading to development of one gametophyte and the death of most megasporocytes are unknown.

The morphological structure of the multiple archesporium in Paeonia veitchii and P. caucasica was studied using cytoembryological methods. We used staining with aniline blue and fluorescence microscopy for visualization of callose on the megasporocyte walls.

All cells of the ovule in investigated Paeonia species are uniform and meristematic at the earliest development stage. The onset of archesporium differentiation correlates with inner integument initiation. The sporogenous complex includes ten to 25 cells which develop asynchronously. The cell located in the central part of the sporogenous complex is differentiated into a megasporocyte earlier than in neighbouring cells. Only this megasporocyte is enveloped in callose; it develops further through to meiosis and forms a female gametophyte. The other megasporocytes degenerate during ovule development.

We consider that callose participates in the mechanism of ‘lateral inhibition’ during megasporocyte maturation. The cell located in the central part of the Paeonia ovule is the first to receive signals that stimulate the onset of megasporogenesis and formation of the callose wall. It is possible that callose participates in blocking of development signals to neighbouring megasporocytes, leading to the arrest of their development.
Objective and Subjective Socioeconomic Status as Sources of Status‐Legitimacy Effect and Legitimation of Income Inequality
Authors: Buchel Ondrej , Luijkx Ruud , Achterberg Peter
Published: October 2020

System justification theory proposes that people are motivated to perceive the existing social system as fair, legitimate, and desirable. However, status‐legitimacy effect, understood as the most disadvantaged living in the most unequal contexts experiencing this need most strongly, has only found mixed support in empirical works. This article presents a comprehensive test of the original reading of status‐legitimacy hypothesis which implied that those with lower objective status are the most motivated to system justify and of the respecified version that posits subjective powerlessness to be the driver of undue system legitimization. Multilevel mixed‐effects linear regression analysis of International Social Survey Programme modules on social inequality, covering almost 50,000 respondents from 28 countries, shows that the mean effects of both subjective and objective status are in line with predictions of economic rationality. To model contextual inequality, we distinguish between an objective measure, Gini, and perceived amounts of income differences as reported by respondents. The analysis testing contextual moderation lends support for the original reading of status‐legitimacy hypothesis—the objectively, rather than subjectively, disadvantaged experience greater motivation to defend the system.
Local Government Volunteer Use: A Resource Dependence and Transaction Costs Explanation
Authors: Kang Seong C. , Nesbit Rebecca , Brudney Jeffrey L.
Published: October 2020

Volunteer use in the United States constitutes a service delivery alternative in which public agencies involve citizens to assist in delivering public services. This article provides a resource dependence and transaction costs explanation for why local governments in the United States may involve volunteers in service delivery. Using a survey of local government service delivery arrangements, we analyze a repeated cross‐sectional dataset derived from four separate years to examine the factors associated with volunteer use. Key findings suggest that fiscal constraints are associated with volunteer use in more municipal government services, while county governments with more resources use volunteers in more services. Contracting out to private organizations is associated with more volunteer use in both municipalities and counties. The findings provide evidence that volunteer use constitutes an effort by local governments in the United States to leverage resources from the environment and to reduce the transaction costs of depending on other organizations.

Evidence for Practice

To capitalize on resources available in the environment, local governments may use volunteers in service delivery.

Local governments confronting fiscal constraints may use volunteers to deliver more services.

Local governments that contract out more services to private organizations may use volunteers in more services to lower administrative costs.

Volunteer use may serve as a strategy for local governments to leverage resources from the environment and to reduce the transaction costs of depending on other organizations.
Impacts of remotely sensed environmental drivers on coral outplant survival
Authors: Foo Shawna A. , Asner Gregory P.
Published: October 2020

Globally, coral reefs are degrading due to a variety of stressors including climate change and pollution. Active restoration is an important effort for sustaining coral reefs where, typically, coral fragments are outplanted onto degraded reefs. Coral outplants, however, can experience mortality in response to a range of stressors. We pair results of outplant monitoring observations with satellite‐based measurements of multiple oceanographic variables to estimate the relative importance of each driver to coral outplant survival. We find that when considering mean environmental conditions experienced by outplants during the monitoring period, particulate organic carbon (POC) levels are most important in determining outplant survival, with certain levels of POC beneficial for outplants. Sea surface temperature anomalies (SSTA) are also important determinants of outplant survival, where survival is greatest in regions with minimal or slightly negative anomalies. Survival also increases with increasing distance to land, likely due to a reduction in negative ridge‐to‐reef effects on coral outplants. When considering the range (min–max) of environmental conditions experienced during the monitoring period, large fluctuations in photosynthetically active radiation (PAR) and POC are most important in determining outplant survival. Increasing outplant depth can help to counter the negative impacts of large fluctuations in environmental variables. We find that a variety of remotely sensed oceanographic variables have significant impacts on survival and should be considered in coral restoration planning to help evaluate potential restoration sites and ultimately maximize coral outplant survival.
A fast algorithm for finding K shortest paths using generalized spur path reuse technique
Authors: Chen Bi Yu , Chen Xiao‐Wei , Chen Hui‐Ping , Lam William H. K.
Published: October 2020

The problem of finding the K shortest paths (KSPs) between a pair of nodes in a road network is an important network optimization problem with broad applications. Yen's algorithm is a classical algorithm for exactly solving the KSP problem. However, it requires numerous shortest path searches, which can be computationally intensive for real large networks. This study proposes a fast algorithm by introducing a generalized spur path reuse technique. Using this technique, shortest paths calculated during the KSP finding process are stored. Accordingly, many shortest path searches can be avoided by reusing these stored paths. The results of computational experiments on several large‐scale road networks show that the introduced generalized spur path reuse technique can avoid more than 98% of shortest path searches in the KSP finding process. The proposed algorithm speeds up Yen's algorithm by up to 98.7 times in experimental networks.
The role of alanine synthesis and nitrate‐induced nitric oxide production during hypoxia stress in Cucurbita pepo nectaries
Authors: Solhaug Erik M. , Roy Rahul , Venterea Rodney T. , Carter Clay J.
Published: October 2020

Floral nectar is a sugary solution produced by nectaries to attract and reward pollinators. Nectar metabolites, such as sugars, are synthesized within the nectary during secretion from both pre‐stored and direct phloem‐derived precursors. In addition to sugars, nectars contain nitrogenous compounds such as amino acids; however, little is known about the role(s) of nitrogen (N) compounds in nectary function. In this study, we investigated N metabolism in Cucurbita pepo (squash) floral nectaries in order to understand how various N‐containing compounds are produced and determine the role of N metabolism in nectar secretion. The expression and activity of key enzymes involved in primary N assimilation, including nitrate reductase (NR) and alanine aminotransferase (AlaAT), were induced during secretion in C. pepo nectaries. Alanine (Ala) accumulated to about 35% of total amino acids in nectaries and nectar during peak secretion; however, alteration of vascular nitrate supply had no impact on Ala accumulation during secretion, suggesting that nectar(y) amino acids are produced by precursors other than nitrate. In addition, nitric oxide (NO) is produced from nitrate and nitrite, at least partially by NR, in nectaries and nectar. Hypoxia‐related processes are induced in nectaries during secretion, including lactic acid and ethanolic fermentation. Finally, treatments that alter nitrate supply affect levels of hypoxic metabolites, nectar volume and nectar sugar composition. The induction of N metabolism in C. pepo nectaries thus plays an important role in the synthesis and secretion of nectar sugar.
Ectopic overexpression of a membrane‐tethered transcription factor gene NAC60 from oilseed rape positively modulates programmed cell death and age‐triggered leaf senescence
Authors: Yan Jingli , Chen Qinqin , Cui Xing , Zhao Peiyu , Gao Shidong , Yang Bo , Liu Jian‐Xiang , Tong Tiantian , Deyholos Michael K. , Jiang Yuan‐Qing
Published: October 2020

Senescence is an integrative final stage of plant development that is governed by internal and external cues. The NAM, ATAF1/2, CUC2 (NAC) transcription factor (TF) family is specific to plants and membrane‐tethered NAC TFs (MTTFs) constitute a unique and sophisticated mechanism in stress responses and development. However, the function of MTTFs in oilseed rape (Brassica napus L.) remains unknown. Here, we report that BnaNAC60 is an MTTF associated with the endoplasmic reticulum (ER) membrane. Expression of BnaNAC60 was induced during the progression of leaf senescence. Translocation of BnaNAC60 into nuclei was induced by ER stress and oxidative stress treatments. It binds to the NTLBS motif, rather than the canonical NAC recognition site. Overexpression of BnaNAC60 devoid of the transmembrane domain, but not the full‐length BnaNAC60, induces significant reactive oxygen species (ROS) accumulation and hypersensitive response‐like cell death in both tobacco (Nicotiana benthamiana) and oilseed rape protoplasts. Moreover, ectopic overexpression of BnaNAC60 devoid of the transmembrane domain, but not the full‐length BnaNAC60, in Arabidopsis also induces precocious leaf senescence. Furthermore, screening and expression profiling identified an array of functional genes that are significantly induced by BnaNAC60 expression. Further it was found that BnaNAC60 can activate the promoter activities of BnaNYC1, BnaRbohD, BnaBFN1, BnaZAT12, and multiple BnaVPEs in a dual‐luciferase reporter assay. Electrophoretic mobility shift assay and chromatin immunoprecipitation coupled to quantitative PCR assays revealed that BnaNAC60 directly binds to the promoter regions of these downstream target genes. To summarize, our data show that BnaNAC60 is an MTTF that modulates cell death, ROS accumulation, and leaf senescence.
Strigolactone biosynthesis, transport and perception
Authors: Mashiguchi Kiyoshi , Seto Yoshiya , Yamaguchi Shinjiro
Published: October 2020

Strigolactones (SLs) are plant hormones that regulate diverse developmental processes and environmental responses. They are also known to be root‐derived chemical signals that regulate symbiotic and parasitic interactions with arbuscular mycorrhizal fungi and root parasitic plants, respectively. Since the discovery of the hormonal function of SLs in 2008, there has been much progress in the SL research field. In particular, a number of breakthroughs have been achieved in our understanding of SL biosynthesis, transport and perception. The discovery of the hormonal function of SL was quite valuable not only as the identification of a new class of plant hormones, but also as the discovery of the long‐sought‐after SL biosynthetic and response mutants. These mutants in several plant species provided us the genetic resources to address fundamental questions regarding SL biosynthesis and perception. Such mutants were further characterized later, and biochemical analyses of these genetically identified factors have uncovered the outline of SL biosynthesis and perception so far. Moreover, new genes involved in SL transport have been discovered through reverse genetic analyses. In this review, we summarize recent advances in SL research with a focus on biosynthesis, transport and perception.
Modeling and Analysis of Iron Mass Transfer Behaviors in Supercritical Boiler Steam-Water System
Authors: Wang Chao , Li Hongyuan , Chen Can , Zeng Zilun , Khan Hasan Izhar , Xu Hong , Xiao Zhuonan
Published: October 2020

Iron (Fe) concentration is a crucial parameter for boiler safety. However, as the working fluid circulation circuits cross each other, and the working fluid operational parameters change over a wide range, monitoring the Fe content and evaluating pipeline safety are very difficult. The mass transfer process of Fe in a complex water circulation system was described by constructing a network calculation model of Fe mass transfer in the steam-water circulation system of a supercritical boiler. The distribution of Fe and the corrosion/deposition rate in the system was calculated and analyzed. The influence of a Fe mass disturbance in single or multiple equipment on the mass distribution of Fe in the system is discussed. The results show that model calculation data is close to the operational data. Under the effect of cyclic mass transfer, both the granular and dissolved Fe cannot be ignored. During one cycle, about 36% of Fe was deposited on the system tube; however, the deposition amount in the steam generator and superheater section accounted for 81.2% of the total deposition amount, and the rest was deposited in the low-temperature pipeline. The influence of disturbance on other nodes in the network is quite different, which provides the possibility of discriminating the location of the disturbance node. The research results can provide a theoretical reference for water chemical control and safety during the operation.
Combined-Hole Film Cooling Designs Based on the Construction of Antikidney Vortex Structure: A Review
Authors: Zhu Rui , Zhang Guohua , Li Shulei , Xie Gongnan
Published: October 2020

Film cooling is one of the most efficient and widely used cooling methods for high-temperature components. The interaction between the film cooling jet and main flow creates the counter-rotating vortex pair (CRVP), which enhances the mixing between coolant and hot stream and lifts the coolant film off the protected surface. The desire to overcome the unfavorable effects of CRVP and thus efficiently improve cooling effectiveness promotes various new combined-hole designs for film cooling. In this review paper, a summary of previous progress on film cooling and a special focus on recent literature related to the combined-hole film cooling designs with less difficulty in machining are provided. The underlying mechanisms of the enhancement in cooling effectiveness and film coverage due to antikidney vortex structure by combined holes are analyzed. Some perspectives on future prospects are finally addressed.
Application of Support Vector Regression and Genetic Algorithm to Reduce Web Warping in Flexible Roll-Forming Process
Authors: Woo Young Yun , Ko Dae-Cheol , Lee Taekyung , Kim Yangjin , Kim Ji Hoon , Moon Young Hoon
Published: October 2020

In a flexible roll-forming process, a metal blank is incrementally deformed into the desired shape with a variable cross-sectional profile by passing the blank through a series of forming rolls. Because of the combined effects of process and material parameters on the quality of the roll-formed product, the approaches used to optimize the roll-forming process have been largely based on experience and trial-and-error methods. Web warping is one of the major shape defects encountered in flexible roll forming. In this study, an optimization method was developed using support vector regression (SVR) and a genetic algorithm (GA) to reduce web warping in flexible roll forming. An SVR model was developed to predict the web-warping height, and a response surface method was used to investigate the effect of the process parameters. In the development of these predictive models, three process parameters—the forming-roll speed condition, leveling-roll height, and bend angle—were considered as the model inputs, and the web-warping height was used as the response variable. The GA used the web-warping height and the cost of the roll-forming system as the fitness function to optimize the process parameters of the flexible roll-forming process. When the flexible roll-forming process was carried out using the optimized process parameters, the obtained experimental results indicated a reduction in web warping. Hence, the feasibility of the proposed optimization method was confirmed.
Optimal Design of Fixture Layout for Compliant Part With Application in Ship Curved Panel Assembly
Authors: Du Juan , Liu Changhui , Liu Jianfeng , Zhang Yansong , Shi Jianjun
Published: October 2020

In a ship assembly process, a large number of compliant parts are involved. The ratio of the part thickness to the length or the width is typically 0.001–0.012. Fixture design is a critical task in the ship assembly process due to its impact on the deformation and dimensional variation of the compliant parts. In current practice, fixtures are typically uniformly distributed under the part to be assembled, which is non-optimal, and large dimensional gaps may occur during assembly. This paper proposed a methodology for the optimal design of the fixture layout in the ship assembly process by systematically integrating direct stiffness method and simulated annealing algorithm, which aims to minimize dimensional gaps along the assembly interface to further improve the quality and efficiency of seam welding. The case study shows that the proposed method significantly reduced the dimensional gaps of the compliant curved panel parts in a ship assembly process.
Deep Learning-Based Data Fusion Method for In Situ Porosity Detection in Laser-Based Additive Manufacturing
Authors: Tian Qi , Guo Shenghan , Melder Erika , Bian Linkan , Guo Weihong “Grace”
Published: October 2020

Laser-based additive manufacturing (LBAM) provides unrivalled design freedom with the ability to manufacture complicated parts for a wide range of engineering applications. Melt pool is one of the most important signatures in LBAM and is indicative of process anomalies and part defects. High-speed thermal images of the melt pool captured during LBAM make it possible for in situ melt pool monitoring and porosity prediction. This paper aims to broaden current knowledge of the underlying relationship between process and porosity in LBAM and provide new possibilities for efficient and accurate porosity prediction. We present a deep learning-based data fusion method to predict porosity in LBAM parts by leveraging the measured melt pool thermal history and two newly created deep learning neural networks. A PyroNet, based on Convolutional Neural Networks, is developed to correlate in-process pyrometry images with layer-wise porosity; an IRNet, based on Long-term Recurrent Convolutional Networks, is developed to correlate sequential thermal images from an infrared camera with layer-wise porosity. Predictions from PyroNet and IRNet are fused at the decision-level to obtain a more accurate prediction of layer-wise porosity. The model fidelity is validated with LBAM Ti–6Al–4V thin-wall structure. This is the first work that manages to fuse pyrometer data and infrared camera data for metal additive manufacturing (AM). The case study results based on benchmark datasets show that our method can achieve high accuracy with relatively high efficiency, demonstrating the applicability of the method for in situ porosity detection in LBAM.
Synthesis and Application of a Single Degree-of-Freedom Six-Bar Linkage With Mixed Exact and Approximate Pose Constraints
Authors: Zhao Xiong , Yu Chennan , Chen Jianneng , Sun Xincheng , Ye Jun , Chen Zhiwei , Zhou Qiaojun
Published: October 2020

Existing research on synthesis methods for single degree-of-freedom (DOF) six-bar linkages mainly include four or five exact poses. However, an ideal trajectory cannot be synthesized using only five exact poses, thus, it is necessary to introduce additional poses to constrain the trajectory. If more exact poses are introduced, then the linkage may have no solution. Therefore, the constraints of the approximate pose are considered to make the trajectory conform to the desired trajectory. This paper successfully introduces mixed poses into a six-bar linkage, based on Z (Z < 5) exact poses and K approximate poses of a given error range, and a new synthesis method for single DOF six-bar linkages is proposed. The solution domain of the linkages synthesized by this method is wide and can be adjusted by controlling the error of the approximate poses, which reduces the difficulty of selecting the solution, ensures theoretical feasibility, and enables the trajectory of the final linkage to more closely match the ideal trajectory. Finally, for the coordinated training of multiple joints in human limbs, a rehabilitation device is designed based on the above six-bar linkage, and a prototype is developed and tested. The test results reveal the accuracy of the proposed method and the effectiveness of rehabilitation training.
Analytical Solution for Temperature Distribution in a Multilayer Body With Spatially Varying Convective Heat Transfer Boundary Conditions on Both Ends
Authors: Zhou Long , Parhizi Mohammad , Jain Ankur
Published: October 2020

Analytical modeling of thermal conduction in a multilayer body is of practical importance in several engineering applications such as microelectronics cooling, building insulation, and micro-electromechanical systems. A number of analytical methods have been used in past work to determine multilayer temperature distribution for various boundary conditions. However, there is a lack of work on solving the multilayer thermal conduction problem in the presence of spatially varying convective heat transfer boundary condition. This paper derives the steady-state temperature distribution in a multilayer body with spatially varying convective heat transfer coefficients on both ends of the body. Internal heat generation within each layer and thermal contact resistance between layers are both accounted for. The solution is presented in the form of an eigenfunction series, the coefficients of which are shown to be governed by a set of linear, algebraic equations that can be easily solved. Results are shown to be in good agreement with numerical simulation and with a standard solution for a special case. The model is used to analyze heat transfer for two specific problems of interest involving spatially varying convective heat transfer representative of jet impingement and laminar flow past a flat plate. In addition to enhancing the theoretical understanding of multilayer heat transfer, this work also contributes toward design and optimization of practical engineering systems comprising multilayer bodies.
Droplet Evaporation of Cu–Al2O3 Hybrid Nanofluid Over Its Residue and Copper Surfaces: Toward Developing a New Analytical Model
Authors: Siddiqui Farooq Riaz , Tso Chi Yan , Fu Sau Chung , Qiu Huihe , Chao Christopher Y. H.
Published: October 2020

Droplet evaporation-based cooling techniques, such as the spray cooling, give high heat transfer rates by utilizing latent energy and are usually preferred in thermal applications. However, with the significant rise in heat dissipation levels for high heat flux devices, these devices cannot be thermally managed due to the limited cooling capacity of existing thermal fluids. In this paper, we report the evaporation of the Cu–Al2O3 hybrid nanofluid (HNF) droplet on a copper surface as well as its own residue surface, developed from the evaporation of the first Cu–Al2O3 HNF droplet. As the main novelty, we identify the critical residue size and investigate the residue size effect, above and below the critical residue size, on evaporation rate of the succeeding Cu–Al2O3 HNF droplet resting over a residue surface. We also develop a new analytical model to estimate the Cu–Al2O3 HNF droplet evaporation rate and compare our results with other existing models. The results show that the Cu–Al2O3 HNF droplet gives 17% higher evaporation rate than a water droplet on a copper surface. Also, the evaporation rate of the Cu–Al2O3 HNF droplet on a residue surface sharply increases by 106% with increasing residue size up to the critical residue size. However, further increasing the residue size above its critical value has a negligible effect on the droplet evaporation rate. Moreover, the evaporation rate of the Cu–Al2O3 HNF droplet on its residue surface is enhanced up to 104% when compared to a copper surface.
Experimental Thermal Study of Ice Slurry Production System Equipped With Direct Contact Heat Exchanger and Spiral Nozzle
Authors: Zhang Yaokang , Su Lin , Xu Zhaoyang , Dong Kaijun , Li Jing
Published: October 2020

For the direct contact ice slurry production system, the obstacles of ice blockage in the nozzle, enormous refrigerant charge, and refrigerant-water separation restrict its commercial application. In this paper, a novel direct contact ice slurry production system is proposed to overcome these obstacles. In this novel system, the horizontal PVC pipe with the spiral nozzle is designed as a direct contact ice slurry generator to avoid ice blockage in the nozzle. The two-phase RC318 is utilized as the system refrigerant. In order to investigate the ice production performance of this novel system, the effects of compressor rotational speed, internal water flowrate, and initial system pressure on ice production performance are experimentally studied, and a lump model is established. The results show that the ice production performance is mainly affected by the compressor rotational speed, but scarcely affected by the internal water flowrate. However, large ice blocks are formed at small internal water flowrate. Besides, the lump model is considered to be able to predict the water temperature. Furthermore, the sinking of the liquid refrigerant exits under the higher initial system pressure, but it can be avoided by reducing the initial system pressure.
Pulsatile Aortic Blood Flow—A Critical Assessment of Boundary Conditions
Authors: Fuchs Alexander , Berg Niclas , Prahl Wittberg Lisa
Published: October 2020

Patient specific (PS) blood flow studies have become popular in recent years but have thus far had limited clinical impact. This is possibly due to uncertainties and errors in the underlying models and simulations setup. This study focuses on the sensitivity of simulation results due to in- and outflow boundary conditions (BCs). Nine different inlet- and seven different outlet BCs were applied to two variants of a healthy subject's thoracic aorta. Temporal development of the flow is essential for the formation and development of helical/spiraling flow where the commonly observed clockwise helical motion may change direction during the heart-cycle. The sensitivity to temporal and spatial variations in the inlet conditions is significant both when expressed in terms of mean and maximal wall shear stress (WSS) and its different averaged variables, e.g., time-averaged WSS (TAWSS), oscillatory shear index (OSI) and relative residence time (RRT). The simulation results are highly sensitive to BC. For example, the maximal WSS may vary over three-orders of magnitude (1–1000 Pa) depending on particular combinations of BCs. Moreover, certain formulations of outlet BCs may be inconsistent with the computed flow field if the underlying assumptions of the space–time dependence are violated. The results of this study show that computational fluid dynamics (CFD) simulations can reveal flow details that can enhance understanding of blood flows. However, the results also demonstrate the potential difficulties in mimicking blood flow in clinical situations.