bluuebunny/crossref_metadata_2025 huggingface dataset:
PaeA (YtfL) protects from cadaverine and putrescine stress in Salmonella Typhimurium and E. coli
Authors: Iwadate Yumi , Ramezanifard Rouhallah , Golubeva Yekaterina A. , Fenlon Luke A. , Slauch James M.
Published: January 2021

Salmonella and E. coli synthesize, import, and export cadaverine, putrescine, and spermidine to maintain physiological levels and provide pH homeostasis. Both low and high intracellular levels of polyamines confer pleiotropic phenotypes or lethality. Here, we demonstrate that the previously uncharacterized inner membrane protein PaeA (YtfL) is required for reducing cytoplasmic cadaverine and putrescine concentrations. We identified paeA as a gene involved in stationary phase survival when cells were initially grown in acidic medium, in which they produce cadaverine. The paeA mutant is also sensitive to putrescine, but not to spermidine or spermine. Sensitivity to external cadaverine in stationary phase is only observed at pH > 8, suggesting that the polyamines need to be deprotonated to passively diffuse into the cell cytoplasm. In the absence of PaeA, intracellular polyamine levels increase and the cells lose viability. Degradation or modification of the polyamines is not relevant. Ectopic expression of the known cadaverine exporter, CadB, in stationary phase partially suppresses the paeA phenotype, and overexpression of PaeA in exponential phase partially complements a cadB mutant grown in acidic medium. These data support the hypothesis that PaeA is a cadaverine/putrescine exporter, reducing potentially toxic levels under certain stress conditions.
A CRISPR/Cas9‐mediated in situ complementation method for Phytophthora sojae mutants
Authors: Qiu Min , Li Yaning , Ye Wenwu , Zheng Xiaobo , Wang Yuanchao
Published: January 2021

Phytophthora sojae is an important model species for oomycete functional genomics research. Recently, a CRISPR/Cas9‐mediated genome‐editing technology has been successfully established in P. sojae, which has been rapidly and widely applied in oomycete research. However, there is an emerging consensus in the biological community that a complete functional gene research system is needed such as developed in the investigations in functional complementation carried out in this study. We report the development of an in situ complementation method for accurate restoration of the mutated gene. We targeted a regulatory B‐subunit of protein phosphatase 2A (PsPP2Ab1) to verify this knockout and subsequent complementation system. We found that the deletion of PsPP2Ab1 in P. sojae leads to severe defects in vegetative hyphal growth, soybean infection, and loss of the ability to produce sporangia. Subsequently, the reintroduction of PsPP2Ab1 into the knockout mutant remedied all of the deficiencies. This study demonstrates the successful implementation of an in situ complementation system by CRISPR/Cas9, which will greatly accelerate functional genomics research of oomycetes in the post‐genomic era.
Characterisation of early ultrastructural changes in the cerebral white matter of CADASIL small vessel disease using high‐pressure freezing/freeze‐substitution
Authors: Rajani Rikesh M. , Dupré Nicolas , Domenga‐Denier Valérie , Van Niel Guillaume , Heiligenstein Xavier , Joutel Anne
Published: January 2021

Aims

The objective of this study was to elucidate the early white matter changes in CADASIL small vessel disease.

Methods

We used high‐pressure freezing and freeze substitution (HPF/FS) in combination with high‐resolution electron microscopy (EM), immunohistochemistry and confocal microscopy of brain specimens from control and CADASIL (TgNotch3R169C) mice aged 4–15 months to study white matter lesions in the corpus callosum.

Results

We first optimised the HPF/FS protocol in which samples were chemically prefixed, frozen in a sample carrier filled with 20% polyvinylpyrrolidone and freeze‐substituted in a cocktail of tannic acid, osmium tetroxide and uranyl acetate dissolved in acetone. EM analysis showed that CADASIL mice exhibit significant splitting of myelin layers and enlargement of the inner tongue of small calibre axons from the age of 6 months, then vesiculation of the inner tongue and myelin sheath thinning at 15 months of age. Immunohistochemistry revealed an increased number of oligodendrocyte precursor cells, although only in older mice, but no reduction in the number of mature oligodendrocytes at any age. The number of Iba1 positive microglial cells was increased in older but not in younger CADASIL mice, but the number of activated microglial cells (Iba1 and CD68 positive) was unchanged at any age.

Conclusion

We conclude that early WM lesions in CADASIL affect first and foremost the myelin sheath and the inner tongue, suggestive of a primary myelin injury. We propose that those defects are consistent with a hypoxic/ischaemic mechanism.
Spirulina breath test indicates differences in gastric emptying based on age, gender, and BMI
Authors: Orsagh‐Yentis Danielle K. , Bai Shasha , Bobbey Adam , Hayes Caitlin , Pusateri Antoinette , Williams Kent
Published: January 2021

Background

Measurements of gastric emptying (GE) by scintigraphy in the pediatric population are based on adult standards. Due to radiation exposure, scintigraphy cannot be performed on healthy children to establish norms of GE in the pediatric population. Stable isotope breath tests (GEBTs) pose no such health risk to children. This study sought to determine the feasibility of a GEBT in children and to investigate whether GE may differ by age, gender, or body mass index (BMI).

Methods

Fifty healthy children 6 to 18 years underwent a 13C‐Spirulina platensis GEBT. Breath samples were obtained at baseline, every 15 min for 1 h, and at 30‐min intervals for 3 h thereafter. Seventeen similarly aged patients with dyspeptic symptoms concurrently underwent scintigraphy and the GEBT.

Key Results

Forty‐six healthy subjects were included in the final analysis. Females had an overall slower rate of GE than did males. At nearly all timepoints, children with a BMI >85th percentile had slower GE than normally weighted children. The GE rate of children aged 6–9 reached a maximum later than did the rate of older children. Thirteen patients undergoing scintigraphy were included in the comparative analysis. The agreement between scintigraphic and GEBT half‐times as measured by the concordance correlation coefficient was 0.383 (95% CI: 0.02–0.65).

Conclusions and Inferences

GEBT was easily accomplished in healthy children. Differences of GE rates by age, gender, and BMI support the need for establishing pediatric standards of GE. One way to establish such standards may be through the use of a GEBT.
Pollen sterols are associated with phylogeny and environment but not with pollinator guilds
Authors: Zu Pengjuan , Koch Hauke , Schwery Orlando , Pironon Samuel , Phillips Charlotte , Ondo Ian , Farrell Iain W. , Nes W. David , Moore Elynor , Wright Geraldine A. , Farman Dudley I. , Stevenson Philip C.
Published: January 2021

Phytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well‐described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in pollen.

We quantified 25 pollen phytosterols in 122 plant species (105 genera, 51 families) to determine their composition and diversity across plant taxa. We searched literature and databases for plant phylogeny, environmental conditions, and pollinator guilds of the species to examine the relationships with pollen sterols.

24‐methylenecholesterol, sitosterol and isofucosterol were the most common and abundant pollen sterols. We found phylogenetic clustering of twelve individual sterols, total sterol content and sterol diversity, and of sterol groupings that reflect their underlying biosynthesis pathway (C‐24 alkylation, ring B desaturation). Plants originating in tropical‐like climates (higher mean annual temperature, lower temperature seasonality, higher precipitation in wettest quarter) were more likely to record higher pollen sterol content. However, pollen sterol composition and content showed no clear relationship with pollinator guilds.

Our study is the first to show that pollen sterol diversity is phylogenetically clustered and that pollen sterol content may adapt to environmental conditions.
The development of posttraumatic stress disorder in individuals with visual impairment: a systematic search and review
Authors: van der Ham Alida J , van der Aa Hilde PA , Brunes Audun , Heir Trond , de Vries Ralph , van Rens Ger HMB , van Nispen Ruth MA
Published: January 2021

Purpose

Posttraumatic stress disorder (PTSD) is a mental health problem with a negative impact on quality of life. Little is known about the relationship between PTSD and visual impairment. According to diagnostic criteria for PTSD, vision loss in itself is generally not considered as a traumatic event. PTSD in people with visual impairment is more likely to be the result of traumatic events, which are not directly related, or are only indirectly related to, visual impairment. The purpose of this systematic review was to describe and discuss the literature on the development of PTSD in people with visual impairment.

Methods

A literature search in PubMed, Embase, PsycINFO and Web of Science was performed up to 15 November 2019 in collaboration with a medical information specialist. Additional search strategies included hand searches of references of retrieved papers and free‐text hand searches in Google Scholar. Thematic content analysis of the extracted data was carried out in order to identify main themes and subthemes.

Results

Findings from 13 articles are presented in a narrative manner along three main themes: (1) posttraumatic stress disorder; (2) traumatic events and (3) impact of traumatic events. People with visual impairments may be at higher risk of being exposed to certain potentially traumatic events. Limited/restricted access to situational information during events may contribute to the stressfulness of the experience. Furthermore, visual impairment may shape the impact of traumatic events.

Conclusions

The current evidence suggests some unique experiences and challenges for people who are visually impaired. PTSD was prevalent in this population, and prevalence rates ranged from 4% to 50%. Future research may focus on gaining insight into the extent and burden of PTSD, and exploring help‐seeking behaviour and treatment needs among those with visual impairment and PTSD.
A transgenic RNAi approach for developing tomato plants immune to Pepinomosaic virus
Authors: Leibman Diana , Ortega‐Parra Nelia , Wolf Dalia , Shterkman Meital , Hanssen Inge , Gal‐On Amit
Published: January 2021

RNA interference (RNAi) or gene silencing is a natural defence response of plants to invading viruses. Here, we applied this approach against pepino mosaic virus (PepMV) isolates in their natural host, tomato. PepMV isolates differ in their genetic sequences, the severity of the disease they induce, and their worldwide distribution. PepMV causes heavy crop losses, mainly due to impaired tomato fruit quality. Resistant varieties are not yet available, despite many years of resistance breeding efforts within the tomato seed industry. To generate broad resistance to PepMV strains, conserved sequences from three different strains of PepMV (US1, LP, and CH2) were synthesized as a single insert and cloned in a hairpin configuration into a binary vector, which was used to transform tomato plants. Transgenic tomato lines that expressed a high level of transgene‐siRNA exhibited immunity to PepMV strains, including a new Israeli isolate. This immunity was maintained even after graft inoculation, in which a transgenic scion was grafted onto nontransgenic infected rootstocks. However, an immune transgenic rootstock was unable to induce resistance in a nontransformed scion. These results provide the first example of engineered immunity to diverse PepMV strains in transgenic tomato based on gene silencing.
Assessing new SSR markers for utility and informativeness in genetic studies of brown rust fungi on wheat, triticale, and rye
Authors: Czajowski Grzegorz , Kosman Evsey , Słowacki Piotr , Park Robert F. , Czembor Paweł
Published: January 2021

The aim of the present study was to validate new simple‐sequence repeat (SSR) markers and use them to assess genetic variability among 24 isolates of Puccinia triticina collected from wheat (Pt‐wheat) and triticale (Pt‐triticale), and 15 isolates of P. recondita f. sp. secalis (Prs) collected from rye. The Pt and Prs isolates were tested for virulence on a set of 35 Thatcher wheat near‐isogenic lines, eight rye lines with known resistance genes, and 53 triticale cultivars with uncharacterized leaf rust resistance. Molecular genotypes were determined using a newly developed set of 34 SSR microsatellite primer pairs. All SSR markers tested on Pt isolates successfully amplified fragments of appropriate size. When tested on the Prs isolates, 21 out of the 34 Pt SSRs amplified expected fragments. Sixteen of these 21 SSRs were polymorphic, providing for the first time microsatellite markers to study genetic variation in Prs. Based on virulence data, variation among Prs isolates was low, probably due to the small number of rye differential lines available. Much higher variation for virulence was observed within the collection of Pt isolates from wheat and triticale, and two separate groups were established with mixed host origin. Substantial genetic variation was detected among the isolates studied with the SSR markers, assuming two different models of SSR evolution (infinite alleles model and stepwise mutation model). The newly developed set of SSR markers proved their effectiveness in detecting genetic variation and should be useful in further population genetics investigations of the two pathogens.
Alpine forbs rely on different photoprotective strategies during spring snowmelt
Authors: Fernández‐Marín Beatriz , Sáenz‐Ceniceros Ana , Solanki Twinkle , Robson Thomas Matthew , García‐Plazaola José Ignacio
Published: January 2021

Snowmelt in alpine ecosystems brings ample water, and together with above‐freezing temperatures, initiates plant growth. In this scenario, rapid activation of photosynthesis is essential for a successful life‐history strategy. But, strong solar radiation in late spring enhances the risk of photodamage, particularly before photosynthesis is fully functional. We compared the photoprotective strategy of five alpine forbs: one geophyte not particularly specialised in subnival life (Crocus albiflorus) and four wintergreens differing in their degree of adaptation to subnival life, from least to most specialised: Gentiana acaulis, Geum montanum, Homogyne alpina and Soldanella alpina. We used distance to the edge of snow patches as a proxy to study time‐dependent changes after melting. We postulated that the photoprotective response of snowbed specialists would be stronger than of more‐generalist alpine meadow species. Fv/Fm was relatively low across wintergreens and even lower in the geophyte C. albiflorus. This species also had the largest xanthophyll‐cycle pool and lowest tocopherol and flavonoid glycoside contents. After snow melting, all the species progressively activated ETR, but particularly the intermediate snowbed species G. acaulis and G. montanum. The photoprotective responses after snowmelt were idiosyncratic: G. montanum rapidly accumulated xanthophyll‐cycle pigments, tocopherol and flavonoid glycosides; while S. alpina showed the largest increase in plastochromanol‐8 and chlorophyll contents and the greatest changes in optical properties. Climate warming scenarios might shift the snowmelt date and consequently alter the effectiveness of photoprotection mechanisms, potentially changing the fitness outcome of the different strategies adopted by alpine forbs.
Audiovisual interactions in speeded discrimination of a visual event
Authors: Kaya Utku , Kafaligonul Hulusi
Published: January 2021

The integration of information from different senses is central to our perception of the external world. Audiovisual interactions have been particularly well studied in this context and various illusions have been developed to demonstrate strong influences of these interactions on the final percept. Using audiovisual paradigms, previous studies have shown that even task‐irrelevant information provided by a secondary modality can change the detection and discrimination of a primary target. These modulations have been found to be significantly dependent on the relative timing between auditory and visual stimuli. Although these interactions in time have been commonly reported, we have still limited understanding of the relationship between the modulations of event‐related potentials (ERPs) and final behavioral performance. Here, we aimed to shed light on this important issue by using a speeded discrimination paradigm combined with electroencephalogram (EEG). During the experimental sessions, the timing between an auditory click and a visual flash was varied over a wide range of stimulus onset asynchronies and observers were engaged in speeded discrimination of flash location. Behavioral reaction times were significantly changed by click timing. Furthermore, the modulations of evoked activities over medial parietal/parieto‐occipital electrodes were associated with this effect. These modulations were within the 126–176 ms time range and more importantly, they were also correlated with the changes in reaction times. These results provide an important functional link between audiovisual interactions at early stages of sensory processing and reaction times. Together with previous research, they further suggest that early crossmodal interactions play a critical role in perceptual performance.
A Panicum‐derived chromosomal segment captured by Hordeum a few million years ago preserves a set of stress‐related genes
Authors: Mahelka Václav , Krak Karol , Fehrer Judith , Caklová Petra , Nagy Nejedlá Michaela , Čegan Radim , Kopecký David , Šafář Jan
Published: January 2021

Intra‐specific variability is a cornerstone of evolutionary success of species. Acquiring genetic material from distant sources is an important adaptive mechanism in bacteria, but it can also play a role in eukaryotes. In this paper, we investigate the nature and evolution of a chromosomal segment of panicoid (Poaceae, Panicoideae) origin occurring in the nuclear genomes of species of the barley genus Hordeum (Pooideae). The segment, spanning over 440 kb in the Asian Hordeum bogdanii and 219 kb in the South American Hordeum pubiflorum, resides on a pair of nucleolar organizer region (NOR)‐bearing chromosomes. Conserved synteny and micro‐collinearity of the segment in both species indicate a common origin of the segment, which was acquired before the split of the respective barley lineages 5–1.7 million years ago. A major part of the foreign DNA consists of several approximately 68 kb long repeated blocks containing five stress‐related protein‐coding genes and transposable elements (TEs). Whereas outside these repeats, the locus was invaded by multiple TEs from the host genome, the repeated blocks are rather intact and appear to be preserved. The protein‐coding genes remained partly functional, as indicated by conserved reading frames, a low amount of non‐synonymous mutations, and expression of mRNA. A screen across Hordeum species targeting the panicoid protein‐coding genes revealed the presence of the genes in all species of the section Stenostachys. In summary, our study shows that grass genomes can contain large genomic segments obtained from distantly related species. These segments usually remain undetected, but they may play an important role in the evolution and adaptation of species.
Hypothermic storage of leukoreduced red blood cells for greater than 21 days is a safe alternative to irradiation
Authors: Mykhailova Olga , Turner Tracey R. , Olafson Carly , Howell Anita , Nahirniak Susan N. , Wizniak Juanita , Gerges Hanan Y. N. , Baldwin Troy , Clarke Gwen , Acker Jason P.
Published: January 2021

Background

Irradiation of red blood cells (RBCs) inactivates residual donor T lymphocytes to prevent transfusion‐associated graft‐vs‐host disease (TA‐GVHD) but can have adverse effects on recipients and inventory management. Reported incidence of TA‐GVHD is lower when leukoreduced RBCs and older blood products are transfused; therefore, the impact of leukoreduction and storage was evaluated as an alternative prevention strategy.

Study Design and Methods

Effectiveness of leukoreduction filters on white blood cell (WBC) proliferation was evaluated by filtering buffy coat (BC) products and isolating residual WBCs. Additionally, leukoreduced RBCs were spiked with 5 × 106 WBCs on Day 21 of hypothermic storage, then stored and processed on Days 7, 14, and 21 to obtain residual WBCs to investigate the impact of hypothermic storage on their viability and proliferative ability. Viability of residual WBCs was assessed by staining with annexin V and an antibody cocktail for flow cytometry analysis. Proliferative ability was assessed by placing carboxyfluorescein diacetate succinimidyl ester–labeled residual WBCs into culture for 6 days with phytohemagglutinin before flow cytometry assessment.

Results

Filtration of BC units depleted WBCs, particularly T lymphocytes, to 0.001% ± 0.003% cells/unit, although proliferative activity remained consistent with prefiltration levels of WBCs. WBCs in stored RBCs remained viable even on Day 21 of storage; however, the proliferative activity decreased to 0.24% ± 0.41%.

Conclusions

Hypothermic storage of RBCs for 21 days or more is sufficient to inactivate T lymphocytes, which may help prevent TA‐GVHD when irradiated RBCs are not available.
Detection of Trypanosoma cruzi in the saliva of diverse neotropical bats
Authors: Bergner Laura M. , Becker Daniel J. , Tello Carlos , Carrera Jorge E. , Streicker Daniel G.
Published: January 2021

Trypanosoma cruzi is widely reported in bats, yet transmission routes remain unclear. We present evidence from metagenomic sequence data that T. cruzi occurs in the saliva of diverse Neotropical bats. Phylogenetic analyses demonstrated that the bat‐associated T. cruzi sequences described here formed part of a bat‐specific clade, suggesting an independent transmission cycle. Our results highlight the value in repurposing metagenomic data generated for viral discovery to reveal insights into the biology of other parasites. Evaluating whether the presence of T. cruzi in the saliva of two hematophagous bat species represents an ecological route for zoonotic transmission of Chagas disease is an interesting avenue for future research.
The Banned Author and the Oriental Publisher
Authors: Boulouque Clémence
Published: January 2021

Chapter 3 examines how the utter disgrace of a rabbinic ban (herem) affected Benamozegh. In a very rare and harsh measure, his Hebrew biblical commentary was banned and burned in 1865 in Aleppo because it contained too many references to sources outside the Jewish tradition. The herem discouraged Benamozegh from any further major enterprise in Hebrew. However, he kept a presence, as a publisher, in the Mediterranean and his endeavors deserve significant attention: it was the largely Hebrew catalogue of his printing press, with a distribution and network of authors spanning the Maghreb and the Mashriq, that functioned as his commitment to an Oriental modernity.
Introduction
Authors: Croce Mariano , Goldoni Marco
Published: January 2021

Chapter abstract: The Introduction explains why it is worth reading Santi Romano’s, Carl Schmitt’s, and Costantino Mortati’s theories against each other. They advanced prototypical solutions to the problem of radical pluralism and how the state could deal with nonstate normative entities. Theirs were seminal reflections on the destiny of the state vis-à-vis the rise of nonstate bodies that rejected the myth of modern statehood and claimed jurisdictional and legislative autonomy. On one hand, these authors’ theories are related to each other as they recognize that the proliferation of normativity is an intrinsic dynamic of social life. On the other, they came to altogether different conclusions on how this dynamic should be governed in order for a political community to come into existence and continue to exist. The Introduction finally elucidates why and in what sense these eminent versions of classic legal institutionalism are key to understanding today’s pluralism.
Pluralism and Order
Authors: Croce Mariano , Goldoni Marco
Published: January 2021

Chapter abstract: The chapter takes stock of the preceding analyses and assesses Romano’s, Schmitt’s, and Mortati’s institutionalism according to two interpretive axes that are extracted from a systematic reading of their work. Both axes provide an oscillation band across which their theories can be located and their differences appreciated. The first axis is built around conceptions of legal knowledge, and its coordinates are represented by political and juristic views of legal knowledge. The second part of the chapter focuses on the other axis: the relation between social relations and nomic force. In this final part, the chapter makes the case that at the intersection of the two axes it is possible to observe how distinctive and original the contributions of Romano, Schmitt, and Mortati are.
Conclusion
Authors: Croce Mariano , Goldoni Marco
Published: January 2021

Chapter abstract: This conclusion offers a brief summary of the main findings of the book. The central concerns of these legal institutionalists—namely, how nomic force molds social relations and the role of legal science in this process—are recapitulated. In the other part of the Conclusions, the emphasis is placed on the relevance of these approaches to law for the contemporary debate, with a focus on the issues caused by globalization and the proliferation of legal orders at different levels. A brief comparison with the methodology adopted by global administrative law, global legal pluralism, and constitutional pluralism is proposed as an illustration of the rich contribution Romano, Schmitt, and Mortati can make to the understanding of the present.
Double-Edged Praise
Authors: Jones Kevin M.
Published: January 2021

This chapter explores the patronage relationships between poets and political elites through the evolution of the panegyric in the colonial state. It looks at how the Hashemite state subsidized popular poets in order to cultivate their own political legitimacy and how dissident poets challenged the state through creative public performances. It argues that modern protest poetry emerged from the dissident panegyric, which became subversive when poets praised political elites for their commitment to policies that those elites could not or would not actually support. The chapter also shows how poetic engagement with social issues like women’s education and veiling shaped popular opinion and contributed to growing social cleavages between generations and how patronage rivalries contributed to new sectarian tensions in Iraqi political life.
Changes in corticospinal excitability during the preparation phase of ballistic and ramp contractions
Authors: Baudry Stéphane , Duchateau Jacques
Published: January 2021

Key points

Changes in corticospinal excitability prior to a contraction may depend on its characteristics, including the rate of torque development.

This study compared the specific modulation of cortical and spinal excitability during the preparation phase (last 500 ms before contraction) of fast (ballistic) and ramp contractions of ankle dorsiflexors, using transcranial magnetic stimulation and peripheral nerve stimulation.

The results indicate earlier changes at the cortical than at the spinal level during the preparation phase of both contraction types.

However, these adjustments are delayed prior to ballistic relative to ramp contractions.

This study suggests that the time course of change in cortical and spinal excitability during the preparation phase of a voluntary action is specific to the intended rate of torque development of the upcoming contraction.

The present study investigated cortical and spinal excitability during the preparation phase of ballistic (BAL) and ramp (RAMP) isometric contractions. To this end, young adults performed BAL and RAMP (1500 ms torque rise time) contractions, reaching a similar torque level, with the ankle dorsiflexor muscles. Transcranial magnetic stimulation of the motor cortex was randomly applied to record motor evoked potentials (MEP) in the tibialis anterior during the last 500 ms preceding the contraction (n = 16). Short‐interval intracortical inhibition (SICI; n = 10) and spinal motor neurone excitability (F‐wave occurrence; n = 8) were also assessed during this period. Data were averaged over 100 ms time windows beginning 500 ms prior to the onset of contractions. An increase in MEP amplitude and a decrease in SICI were observed from the 200–100 ms and 300–200 ms time windows prior to BAL and RAMP contractions (P < 0.05), respectively, with greater changes prior to RAMP than to BAL within the 300–200 ms time window (P < 0.05). F‐wave occurrence, used to assess spinal motor neurone excitability, increased prior to RAMP (200–100 ms, P < 0.05) but not BAL contractions. Data obtained in a few participants during the last 100 ms confirmed a delayed and steeper rise in corticospinal excitability prior to BAL contractions. These results indicate earlier changes at the cortical than at the spinal level, with delayed changes prior to BAL contractions. This study suggests that the time course of change in cortical and spinal excitability during the preparation phase of a voluntary action is specific to the intended rate of torque development of the upcoming contraction.
Contact Stability and Contact Safety of a Magnetic Resonance Imaging-Guided Robotic Catheter Under Heart Surface Motion
Authors: Hao Ran , Erdem Tuna E. , Çavuşoğlu M. Cenk
Published: January 2021

Contact force quality is one of the most critical factors for safe and effective lesion formation during catheter based atrial fibrillation ablation procedures. In this paper, the contact stability and contact safety of a novel magnetic resonance imaging (MRI)-actuated robotic cardiac ablation catheter subject to surface motion disturbances are studied. First, a quasi-static contact force optimization algorithm, which calculates the actuation needed to achieve a desired contact force at an instantaneous tissue surface configuration is introduced. This algorithm is then generalized using a least-squares formulation to optimize the contact stability and safety over a prediction horizon for a given estimated heart motion trajectory. Four contact force control schemes are proposed based on these algorithms. The first proposed force control scheme employs instantaneous heart position feedback. The second control scheme applies a constant actuation level using a quasi-periodic heart motion prediction. The third and the last contact force control schemes employ a generalized adaptive filter-based heart motion prediction, where the former uses the predicted instantaneous position feedback, and the latter is a receding horizon controller. The performance of the proposed control schemes is compared and evaluated in a simulation environment.
Incipient Surge Detection in Large Volume Energy Systems Based on Wigner–Ville Distribution Evaluated on Vibration Signals
Authors: Champ Carlo Alberto Niccolini Marmont Du Haut , Silvestri Paolo , Ferrari Mario Luigi , Massardo Aristide Fausto
Published: January 2021

Compressor response investigation in nearly unstable operating conditions, like rotating stall and incipient surge, is a challenging topic nowadays in the turbomachinery research field. Indeed, turbines connected with large-size volumes are affected by critical issues related to surge prevention, particularly during transient operations. Advanced signal-processing operations conducted on vibrational responses provide an insight into possible diagnostic and predictive solutions which can be derived from accelerometer measurements. Indeed, vibrational investigation is largely employed in rotating-machine diagnostics together with time-frequency analysis such as smoothed pseudo-Wigner Ville (SPWVD) time-frequency distribution (TFD) considered in this paper. It is characterized by excellent time and frequency resolutions and thus it is effectively employed in numerous applications in the condition monitoring of machinery. The aim and the innovation of this work regards SPWVD utilization to study turbomachinery behavior in detail in order to identify incipient surge conditions in the centrifugal compressor starting from operational vibrational responses measured at significant plant locations. The so developed investigation allows us to assess the reliability of this innovative technique with respect to conventional ones in this field of research, highlighting at the same time its qualities and drawbacks in detecting fluid machinery unstable behavior. To this aim, an experimental campaign has been conducted on a T100 microturbine connected with several volume sizes and this has allowed to assess diagnostic technique reliability in plant configurations with different dynamic properties. The results show that SPWVD is able to successfully identify system evolution toward an unstable condition, by recognizing different levels and features of the particular kind of instability that is going to take place within the plant. Instability phenomena regarding rolling bearings have also been identified and their interaction with surge onset has been investigated for diagnostic purposes.
Analysis of the Heat Transfer Within Combustor Liners Using a Combined Monte Carlo and Two-Flux Method
Authors: Johnson Andressa L. , Zhao Xinyu
Published: January 2021

One consequence of increasing efficiency of gas turbine combustors is higher temperatures within the combustor. Management of larger heat load has been advanced to protect the combustor wall and turbines, and among those are thermal barrier coatings (TBCs). Historically, both the flame and TBCs have received a simplified radiation treatment using effective absorptivities and emissivities. In this study, non-gray radiation is compared with gray and black radiation by combining three-dimensional Monte Carlo Ray Tracing solution of non-gray flames in a model gas turbine combustor to one-dimensional energy balance within combustor liners. A recent large eddy simulation of a gas turbine combustor is analyzed, where both gray and non-gray models are exercised. A two-band spectral model is employed for the TBC, where a translucent band and an opaque band are identified. A line-by-line treatment for gas-phase radiation is adopted, and the incident radiative energy on the combustor wall is collected using the MCRT solver, where the fraction of radiative energy within the translucent band is collected and compared with those obtained from the blackbody assumption. The temperature along the multilayered combustor wall is computed, and parametric comparison is conducted. The effects of the nongray flame radiation are more prominent at elevated pressures than at atmospheric pressure. The gray model is found to over-predict the TBC temperature, which leads to a difference of approximately 150 K in the prediction of peak temperature on the hot side of the TBC.
The Effect of Reaction on Compressor Performance
Authors: Chana Krishan S. , Miller Robert J.
Published: January 2021

Reaction is the fundamental parameter by which the asymmetry of the velocity triangle of a stage is set. Little is understood about the effect that a reaction has on either the efficiency or the operating range of a compressor. A particular difficulty in understanding the effect of the reaction is that the rotor and stator have a natural asymmetry caused by the centrifugal effects in the rotor boundary layer being much larger than that in the stator boundary layer. In this paper, a novel approach has been taken: McKenzie’s “linear repeating stage” concept is used to remove the centrifugal effects. The centrifugal effects are then reintroduced as a body force. This allows the velocity triangle effect and centrifugal force effect to be decoupled. The paper shows the surprising result that, depending on how the solidity is set, a 50% reaction stage can either result in the maximum, or the minimum, profile loss. When the centrifugal effects are removed, 50% reaction is shown to minimize endwall loss, maximize stage efficiency, and maximize operating range. When the centrifugal effects are reintroduced, the compressor with the maximum design efficiency is found to rise in the reaction by 5% (from 50% reaction to 55% reaction) and the compressor with the maximum operating range is found to rise in the reaction by 15% (from 50% reaction to 65% reaction).
Examining Experienced S&C Coaches’ Reflections on the Effectiveness of Psychosocial Behaviors in Coaching
Authors: Szedlak Christoph , Batey Jo , Smith Matthew J. , Church Matthew
Published: January 2021

This study aimed to examine elite, experienced strength and conditioning (S&C) coaches’ reflections on the effectiveness of psychosocial behaviors in S&C coaching. In particular, this study aimed to explore which psychosocial behaviors are essential, the process of how these might influence coaching practice, and how the development of psychosocial behaviors should be encouraged. Eight elite, experienced S&C coaches were recruited and partook in a semistructured interview. Using a reflexive thematic analysis, six themes were identified: understanding athlete’s needs, communicating effectively, caring and connecting with the athlete, practicing what you preach, the importance of reflective practice, and the contribution of formal training. The findings of this study enhance the literature by highlighting that elite, experienced S&C coaches perceive psychosocial behaviors to be essential in effective S&C coaching practice. In particular, the findings describe the processes of how identified psychosocial behaviors might positively influence athlete development by enhancing motivation, buy-in, and autonomy. In addition, the authors’ results suggest that current S&C coach development programs are limited in facilitating the learning of psychosocial behaviors. Thus, their findings strengthen the call for S&C coach educators to utilize constructivist learning strategies including facilitated reflection to encourage the development of essential psychosocial behaviors that contribute to the holistic development of the athlete.
Errors in Measuring Glenohumeral Arthrokinematics With 2-Dimensional Fluoroscopy
Authors: Makhija Meena , Sethi Jasobanta , Kataria Chitra , Singh Harpreet , Ludewig Paula M. , Phadke Vandana
Published: January 2021

Two-dimensional fluoroscopic imaging allows measurement of small magnitude humeral head translations that are prone to errors due to optical distortion, out-of-plane imaging, repeated manual identification of landmarks, and magnification. This article presents results from in vivo and in vitro fluoroscopy-based experiments that measure the errors and variability in estimating the humeral head translated position in true scapular plane and axillary views. The errors were expressed as bias and accuracy. The variability with repeated digitization was calculated using the intraclass correlation coefficient (ICC) and the standard error of measurement. Optical distortion caused underestimation of linear distances. The accuracy was 0.11 and 0.43 mm for in vitro and in vivo experiments, respectively, for optical distortion. The intrarater reliability was excellent for both views (ICC = .94 and .93), and interrater reliability was excellent (ICC = .95) for true scapular view but moderate (ICC = .74) for axillary views. The standard error of measurement ranged from 0.27 to 0.58 mm. The accuracy for the humeral head position in 10° out of true scapular plane images ranged from 0.80 to 0.87 mm. The current study quantifies the magnitude of error. The results suggest that suitable measures could be incorporated to minimize errors and variability for the measurement of glenohumeral parameters.
Engaging Fathers to Improve Physical Activity and Nutrition in Themselves and in Their Preschool-Aged Children: The “Healthy Youngsters, Healthy Dads” Feasibility Trial
Authors: Morgan Philip J. , Collins Clare E. , Barnes Alyce T. , Pollock Emma R. , Kennedy Stevie-Lee , Drew Ryan J. , Saunders Kristen L. , Grounds Jacqueline A. , Rayward Anna T. , Young Myles D.
Published: January 2021

Background: Few lifestyle programs for young children have targeted fathers. This study examined the feasibility of a lifestyle intervention for fathers and their preschool-aged children. Method: A total of 24 father/preschool child dyads were recruited from Newcastle, Australia, into a single-arm, feasibility trial (baseline and 3-mo postbaseline assessments). The 9-session program aimed to improve physical activity and dietary habits of fathers and children. A priori feasibility benchmarks targeted recruitment (15 dyads), eligibility rate (>60%), attendance (80%), retention (≥85%), and program acceptability (≥4 out of 5). Acceptability of data collection procedures, research team program/resource management, home-program compliance, and preliminary intervention outcomes were also assessed. Results: Feasibility benchmarks were surpassed for recruitment (24 dyads), eligibility rate (61.5%), attendance (89%), retention (100%), and program acceptability (4.6 out of 5). Data collection procedures were acceptable. Challenges included mothers reporting their own dietary intake rather than their child’s, children moving during body composition measurement, and resetting pedometers. Resource and program management were excellent. Most families met home-program requirements (83%). Preliminary intervention outcomes were encouraging for fathers and children. Conclusion: Program feasibility was demonstrated by excellent recruitment, attendance, acceptability, retention, program administration, and promising preliminary intervention outcomes. A few data collection difficulties were identified. A larger scale efficacy trial is warranted.
A Systematic Review on the Prevalence of Physical Activity, and Barriers and Facilitators to Physical Activity, in Informal Carers in the United Kingdom
Authors: Horne Joanna , Kentzer Nichola , Smith Lee , Trott Mike , Vseteckova Jitka
Published: January 2021

Background: It is estimated that 17% of the UK adult population are informal carers, usually for a family member, with a majority reporting that they are not able to engage in physical activity as much as they would like. The aim of this review is to provide a greater understanding of the prevalence of, and barriers and facilitators to, physical activity of informal carers in the United Kingdom. Methods: A systematic review of relevant databases and grey literature was undertaken, following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidance, from its inception until July 17, 2020. Results: Barriers to physical activity include increasing aging, not wanting to leave the caree alone, the caree being unable to take part in activities, health conditions, fatigue, lack of time, and difficulties in changing the routine for the caree. Facilitators include an appreciation of the benefits of engaging in exercise, previous participation in activities, group activities with similar people, and having some free time. Conclusions: Due to the paucity of research into the prevalence of, and barriers and facilitators to, physical activity in informal carers in the United Kingdom, this systematic review highlights the need for further research, focusing primarily on the physical activity of informal carers caring for individuals with a range of conditions. A further systematic review exploring these issues internationally is warranted.
Colorimetric properties and structural evolution of cathodic electrochromic WO3 thin films
Authors: Dong Dongmei , Robichaud Jacques , Djaoued Yahia
Published: January 2021

Cathodic amorphous tungsten trioxide (WO3) thin films have been deposited by reactive direct current magnetron sputtering and have been studied for their colorimetric and electrochromic properties. Those studies were carried out under two different potential cycling process: (i) switching mode (the response between coloration and bleaching in increasing potential steps) and (ii) modulation mode (the stepwise modulation to coloration with increasing potential and back to bleaching). Optical measurements, performed as a function of applied potential, showed excellent transmittance contrasts (∼80%) between colored and bleached states. The color stimuli and the changes that take place upon reversible switching or modulation were recorded based on the Commisson International de l’Éclairage (CIE) system. It was found that, under various potentials, significant changes occurred in the hue and saturation for WO3, as exhibited by the CIE 1931 xy chromaticity coordinates. As WO3 was reduced (W6+ + e– → W5+), a sharp decrease in luminance was observed. Excellent reversibility is demonstrated not only by colorimetric properties, but also by the corresponding intrinsic structures of the films, as investigated by µ-Raman spectroscopy. Furthermore, the WO3 films displayed a fast response time and good long-term cycling durability, which was attributed to their amorphous nature.
A national tree-ring data repository for Canadian forests (CFS-TRenD): structure, synthesis, and applications
Authors: Girardin Martin P. , Guo Xiao Jing , Metsaranta Juha , Gervais David , Campbell Elizabeth , Arsenault André , Isaac-Renton Miriam , Harvey Jill E. , Bhatti Jag , Hogg Edward H.
Published: January 2021

Understanding the magnitude and cause of variation in tree growth and forest productivity is central to sustainable forest management. Measurements of annual growth rings allow assessments of individual-tree, tree population, and forest ecosystem vulnerabilities to drought stress or other changing forest disturbance regimes (insects, diseases, fire), which can be used to identify areas at greatest risk of forest losses. Given a heightened demand for tree-ring data, we consolidated and synthesized tree-ring studies and datasets gathered over the past 30 years in Canada by scientists with the Canadian Forest Service and research partners. We incorporated these datasets into a data repository that currently contains tree-ring measurements from 40 206 tree samples from 4594 sites and 62 tree species from all Canadian provinces and territories. Through our synthesis, we demonstrate the value of such large ensembles of tree-ring data for identifying patterns in tree growth over large spatial scales by mapping pan-Canadian drought sensitivity. Overall, we found high coherence in the samples analyzed; low coherence was generally limited to data-poor regions and species. Drought sensitivity was widespread across species and regions: 34% of sampled trees displayed a significant positive relationship between annual growth increment and summer soil moisture index. Dependence upon water availability in species Picea mariana (Mill.) BSP, Pinus banksiana Lamb., Pinus contorta Douglas ex Loudon, and Pseudotsuga menziesii (Mirb.) Franco was more strongly expressed in the warmest regions of the species’ range; for species Picea glauca (Moench) Voss and Populus tremuloides Michx., drought sensitivity was stronger in the driest regions. This unprecedented consolidation and synthesis of tree-ring data will enable new research initiatives (e.g., meta-analyses) aimed at improved understanding of the drivers, patterns, and implications of changes in tree growth, as well as facilitating new research collaborations in earth and environmental sciences. Among other things, there is a need for expanding the spatial distribution of sites across Canada’s northern regions, increasing the number of samples collected from older stands and angiosperm species, and integrating datasets from studies that evaluate the effects of silvicultural experiments, including provenance and progeny trials, on tree growth.