bluuebunny/crossref_metadata_2025 huggingface dataset:
AMP-activated protein kinase: A key enzyme to manage nutritional stress responses in parasites with complex life cycles
Authors: Sternlieb Tamara , Schoijet Alejandra C. , Genta Patricio D. , Alonso Guillermo D.
Published: April 2020

Trypanosoma cruzi, the etiological agent of Chagas disease, has a digenetic life cycle. In its passage from the insect vector to the mammalian host, and vice versa, it must be prepared to cope with abrupt changes in environmental conditions in order to survive. Sensing and signaling pathways that allow the parasite to adapt, have unique characteristics with respect to their hosts and other free-living organisms. Many of the canonical proteins involved in these transduction pathways have not yet been found in the genomes of these parasites, because they present divergences either at the functional, structural and/or protein sequence level. All of this makes these pathways promising targets for therapeutic drugs.

The AMP-activated protein kinase (AMPK) is a serine/threonine kinase activated by environmental stresses that results in reduction of ATP and increase of AMP levels. Thus, AMPK is regarded as a fuel gauge, functioning both as a nutrient and an energy sensor, to maintain energy homeostasis and, eventually, to protect cells from death by nutrient starvation.

In the present study, we report the characterization of AMPK complexes for the first time inT. cruziand describe the function of TcAMPK as a novel regulator of nutritional stress in epimastigote forms. We demonstrate that this complex possesses specific AMPK kinase activity in epimastigotes, which is inhibited by Compound C and is modulated by carbon source availability. In addition, TcAMPKα2 subunit has an unprecedented functional substitution (Ser x Thr) at the activation loop and its overexpression in epimastigotes led to higher autophagic activity during prolonged nutritional stress. Moreover, the over-expression of the catalytic subunits resulted in antagonistic phenotypes associated with proliferation. Together, these results point to a role of TcAMPK in autophagy and nutrient sensing, key processes for the survival of trypanosomatids and for its life cycle progression.
Shape changes and cooperativity in the folding of central domain of the 16S ribosomal RNA
Authors: Hori Naoto , Denesyuk Natalia A , Thirumalai D
Published: April 2020

Both the small and large subunits of the ribosome, the molecular machine that synthesizes proteins, are complexes of ribosomal RNAs (rRNAs) and a number of proteins. In bacteria, the small subunit has a single 16S rRNA whose folding is the first step in its assembly. The central domain of the 16S rRNA folds independently, driven either by Mg2+ions or by interaction with ribosomal proteins. In order to provide a quantitative description of ion-induced folding of the ~350 nucleotide rRNA, we carried out extensive coarse-grained molecular simulations spanning Mg2+concentration between 0−30 mM. The Mg2+dependence of the radius of gyration shows that globally the rRNA folds cooperatively. Surprisingly, various structural elements order at different Mg2+concentrations, indicative of the heterogeneous assembly even within a single domain of the rRNA. Binding of Mg2+ions is highly specific, with successive ion condensation resulting in nucleation of tertiary structures. We also predict the Mg2+-dependent protection factors, measurable in hydroxyl radical footprinting experiments, which corroborate the specificity of Mg2+-induced folding. The simulations, which agree quantitatively with several experiments on the folding of a three-way junction, show that its folding is preceded by formation of other tertiary contacts in the central junction. Our work provides a starting point in simulating the early events in the assembly of the small subunit of the ribosome.
Interdependence between histone marks and steps in Pol II transcription
Authors: Wang Zhong , Chivu Alexandra G. , Choate Lauren A. , Rice Edward J. , Miller Donald C. , Chu Tinyi , Chou Shao-Pei , Kingsley Nicole B. , Petersen Jessica L. , Finno Carrie J. , Bellone Rebecca R. , Antczak Douglas F. , Lis John T. , Danko Charles G.
Published: April 2020

The role of histone modifications in transcription remains incompletely understood. Here we used experimental perturbations combined with sensitive machine learning tools that infer the distribution of histone marks using maps of nascent transcription. Transcription predicted the variation in active histone marks and complex chromatin states, like bivalent promoters, down to single-nucleosome resolution and at an accuracy that rivaled the correspondence between independent ChIP-seq experiments. Blocking transcription rapidly removed two punctate marks, H3K4me3 and H3K27ac, from chromatin indicating that transcription is required for active histone modifications. Transcription was also required for maintenance of H3K27me3 consistent with a role for RNA in recruiting PRC2. A subset of DNase-I hypersensitive sites were refractory to prediction, precluding models where transcription initiates pervasively at any open chromatin. Our results, in combination with past literature, support a model in which active histone modifications serve a supportive, rather than a regulatory, role in transcription.
Genetically targeted reporter imaging of deep neuronal network in the mammalian brain
Authors: Shimojo Masafumi , Ono Maiko , Takuwa Hiroyuki , Mimura Koki , Nagai Yuji , Fujinaga Masayuki , Kikuchi Tatsuya , Okada Maki , Seki Chie , Tokunaga Masaki , Maeda Jun , Takado Yuhei , Takahashi Manami , Minamihisamatsu Takeharu , Zhang Ming-Rong , Tomita Yutaka , Suzuki Norihiro , Maximov Anton , Suhara Tetsuya , Minamimoto Takafumi , Sahara Naruhiko , Higuchi Makoto
Published: April 2020

Positron Emission Tomography (PET) allows biomolecular tracking, while PET monitoring of brain networks has been hampered by the lack of a suitable reporter. Here, we describein vivobrain imaging that takes advantage of bacterial dihydrofolate reductase, ecDHFR, and its unique antagonist, TMP. In mice, peripheral administration of radiofluorinated and fluorescent TMP analogs enabled PET and intravital microscopy, respectively, of neuronal ecDHFR expressions. This technique is applicable to the visualization of neuronal ensemble activities elicited by chemogenetic manipulation in the mouse hippocampus. Notably, ecDHFR-PET offers mapping of neuronal projections in non-human primate brains, indicating the availability of ecDHFR-based tracking technologies for network monitoring. Finally, we demonstrate the utility of TMP analogs for PET assays of turnover and self-assembly of proteins tagged with ecDHFR mutants. Our findings may facilitate a broad spectrum of PET analyses of a mammalian brain circuit at molecular levels that were not previously applicable for technical reasons.
ArlCDE form the archaeal switch complex
Authors: Li Zhengqun , Rodriguez-Franco Marta , Albers Sonja-Verena , Quax Tessa E. F.
Published: April 2020

Cells require a sensory system and a motility structure to achieve directed movement. Bacteria and archaea both possess rotating filamentous motility structures that work in concert with the sensory chemotaxis system. This allows microorganisms to move along chemical gradients. The central response regulator protein CheY can bind to the motor of the motility structure, the flagellum in bacteria and the archaellum in archaea. Both motility structures have a fundamentally different protein composition and structural organization. Yet, both systems receive input from the chemotaxis system. We applied a fluorescent microscopy approach in the model euryarchaeonHaloferax volcanii, and shed light on the sequence order in which signals are transferred from the chemotaxis system to the archaellum. Our findings indicate that the euryarchaeal specific ArlCDE are part of the archaellum motor and that they directly receive input from the chemotaxis system via the adaptor protein CheF. Hence, ArlCDE are an important feature of the archaellum of euryarchaea, are essential for signal transduction during chemotaxis and represent the archaeal switch complex.
5’ modifications to CRISPR Cas9 gRNA can change the dynamics and size of R-loops and inhibit DNA cleavage
Authors: Mullally Grace , van Aelst Kara , Naqvi Mohsin M. , Diffin Fiona M. , Karvelis Tautvydas , Gasiunas Giedrius , Šikšnys Virginijus , Szczelkun Mark D.
Published: April 2020

A key aim in exploiting CRISPR-Cas is the engineering of gRNA to introduce additional functionalities, ranging from small nucleotide changes that increase efficiency of on-target binding to the inclusion of large functional RNA aptamers and ribonucleoproteins (RNPs. Interactions between gRNA and Cas9 are crucial for RNP complex assembly but several distinct regions of the gRNA are amenable to modification. Using a library of modified gRNAs, we usedin vitroensemble and single-molecule assays to assess the impact of RNA structural alterations on RNP complex formation, R-loop dynamics, and endonuclease activity. Our results indicate that R-loop formation and DNA cleavage activity are essentially unaffected by gRNA modifications of the Upper Stem, first Hairpin and 3’ end. In contrast, 5’ additions of only two or three nucleotides reduced R-loop formation and cleavage activity of the RuvC domain relative to a single nucleotide addition. Such gRNA modifications are a common by-product ofin vitrotranscribed gRNA. We also observed that addition of a 20 nt RNA hairpin to the 5’ end supported formation of a stable ~9 bp R-loop that could not activate DNA cleavage. These observations will assist in successful gRNA design.
Inelastic buckling mode interactions and resonance instabilities in thin-walled columns due to the fatigue damage
Authors: Milašinović Dragan D. , Marić Petar , Živanov Žarko , Hajduković Miroslav
Published: April 2020

Purpose

The problems of inelastic instability (buckling) and dynamic instability (resonance) have been the subject of extensive investigation and have received wide attention from the structural mechanics community. This paper aims to tackle these problems in thin-walled structures, taking into account geometrical and/or material non-linearity.

Design/methodology/approach

The inelastic buckling mode interactions and resonance instabilities of prismatic thin-walled columns are analysed by implementing the semi-analytical finite strip method (FSM). A scalar damage parameter is implemented in conjunction with a material modelling named rheological-dynamical analogy to address stiffness reduction induced by the fatigue damage.

Findings

Inelastic buckling stresses lag behind the elastic buckling stresses across all modes, which is a consequence of the viscoelastic behaviour of materials. Because of the lag, the same column length does not always correspond to the same mode at the elastic and inelastic critical stress.

Originality/value

This paper presents the influence of mode interactions on the effective stresses and resonance instabilities in thin-walled columns due to the fatigue damage. These mode interactions have a great influence on damage variables because of the fatigue and effective stresses around mode transitions. In its usual semi-analytical form, the FSM cannot be used to solve the mode interaction problem explained in this paper, because this technique ignores the important influence of interaction of the buckling modes when applied only for undamaged state of structure
Behind the scenes
Authors: Liu Yang , Shi Yongjiang
Published: April 2020

Purpose

Prior studies on product standardization–adaptation in multinational corporations (MNCs) have revealed environmental factors that can influence the choices of MNCs. However, these studies have not shown how these choices are made behind the scenes in new product development (NPD). In many industries, MNCs face the dual pressures for product standardization and adaptation from the environment. This study aims to explore how MNCs facing dual pressures can make choices of product standardization–adaptation in NPD.

Design/methodology/approach

A qualitative case study of four high-performing MNCs was conducted. The four MNCs were selected using the theoretical sampling approach. Data were collected, mainly through 74 semi-structured interviews. Coding was conducted and four aggregate dimensions were generated.

Findings

This study reveals that choices of product standardization–adaptation are made through a process in MNCs’ NPD, including four steps – organizing for NPD, organizational diversity, cross-unit integration and combination of design practices. In addition, MNCs adopt different process variants to address different environmental pressures.

Research limitations/implications

This research focuses on high-performing MNCs in manufacturing industries. Future research can explore different types of firms.

Practical implications

Managers in MNCs should focus more on the process of choices for product standardization–adaptation, than on the level of product standardization–adaptation. They should also keep monitoring the environmental pressure and employ experienced engineers.

Originality/value

By focusing on NPD, the authors shift the attention from product standardization–adaptation to product feature standardization–adaptation in MNCs, which is a fresh and refined perspective. The authors show a process in NPD composed of activities and mechanisms that managers might use for handling product standardization–adaptation challenges in MNCs. The authors contribute to the area of cross-unit integration in MNCs’ NPD by revealing mental mechanisms for mitigating tensions in cross-unit interactions.
Entrepreneurial uncertainty in context: an ethnomethodological perspective
Authors: Campbell Betsy
Published: April 2020

Purpose

This paper seeks to advance research into entrepreneurial uncertainty. Few researchers have attended to the endogenous means by which entrepreneurial teams account for uncertainty in context. This article begins to unpack the concept of uncertainty as an entrepreneurs’ phenomenon by investigating entrepreneurial teams’ situated ways of verbally attending to and accounting for uncertainty in their routine work.

Design/methodology/approach

The study draws on the ethnomethodological traditions of Conversation Analysis and interaction order to analyze naturally occurring interactions that have been recorded by entrepreneurial teams in context. It considers entrepreneurial uncertainty as a matter that teammates draw upon and orient to in the process of their naturally occurring workplace interactions.

Findings

First, it suggests that the endogenous means by which entrepreneurs recognize, account for, and respond to uncertainties is identifiable in a team’s naturally occurring conversations. It transforms entrepreneurial uncertainty as a matter of cognition into a matter of practice that is observable in the structure and order of authentic interaction. Second, it reveals the “epistemic engine” that entrepreneurial teams use to demonstrate greater or lesser levels of knowing and to move to closure that is not marked by the full elimination of uncertainties but by the establishment of a shared sense of not knowing.

Practical implications

By adhering to the detailed interactional focus of Conversation Analysis, this article emphasizes the value that the structure and order of entrepreneurial conversations can offer to research on entrepreneurship as practice. It points to future research on matters of effectuation and expertise that will be relevant to scholars and educators of entrepreneurship. It also helps to bridge the gap between scholarly research and entrepreneurial work as experienced by practitioners.

Originality/value

This article shows the mundane verbal means by which entrepreneurs account for uncertainties in their everyday work. It reframes entrepreneurial uncertainty, transforming it from a matter of cognition to an accomplishment of practice. It suggests that entrepreneurial uncertainty is a practical matter that is recognized by and accounted for in the conversations of entrepreneurial teams in context.
The impact of lean manufacturing practices on operational and financial performance: the mediating role of agile manufacturing
Authors: Khalfallah Meriem , Lakhal Lassaad
Published: April 2020

Purpose

This empirical study aims to explore the link between lean manufacturing practices (total quality management, just-in-time production, just-in-time purchasing, total productive/preventive maintenance), agile manufacturing, and operational and financial performance.

Design/methodology/approach

Data were collected from 205 Tunisian manufacturing firms, and the results were analyzed using structural equation modeling.

Findings

The results indicate that (1) lean manufacturing practices have a direct positive relationship with agile manufacturing except for just-in-time production, (2) agile manufacturing has a positive impact on operational performance and (3) lean manufacturing practices did not seem to contribute directly to operational performance. However, this relationship is significant when it is mediated through agile manufacturing.

Research limitations/implications

This paper shows practitioners the importance of lean manufacturing practices to support agile manufacturing and the key role of agile manufacturing to ensure operational performance.

Originality/value

This paper presents an innovative approach since it studies simultaneously the three dimensions of lean manufacturing and their relationship with agile manufacturing and organizational performance.
Modelling frequency of visits to the shopping centres as a part of consumer's preferences: case study from the Czech Republic
Authors: Kunc Josef , Reichel Vlastimil , Novotná Markéta
Published: April 2020

Purpose

Effective management of shopping centres requires a good understanding of the consumers' behaviour and preferences as well as meeting the demand-side needs. The purpose of this paper is to elucidate the factors affecting the frequency of shopping centres' visits, providing implications for shopping centre managers from the perspective of a Czech consumer.

Design/methodology/approach

The study was carried out in one of the Czech shopping centres in Brno due to its potentially standardisable common characteristics derived from the observation in the scatter plot. The standardized questionnaire survey on consumer shopping behaviour was conducted on a sample of more than 1,000 customers. The linear probability model and the logit model were applied to estimate impacts of included sociodemographic variables on the outcome.

Findings

The findings on the frequency of visits give an overview of the sociodemographic and spatial determinants increasing the visit regularity. From the managerial point of view, the importance of customers' activities and purposes is highlighted.

Practical implications

The implications can be provided to managers challenging to demand management and considering the investment projects. We come up with certain suggestions in terms of market segmentation, based on sociodemographic characteristics and shopping behaviour.

Originality/value

The paper provides insights into the preferences of the Czech consumers and extends the previous analysis of shopping behaviour by developing the statistical properties and demonstrating the variables and their influence on the frequency of visit.
Analyzing enterprise information system’s feature use: a data-driven perspective
Authors: Jia Yu , Ge Shilun , Wang Nianxin
Published: April 2020

Purpose

The purpose of this study is to propose a data-driven perspective to analyze enterprise information system (EIS) feature use for understanding what and how the system features are actually used in the organization.

Design/methodology/approach

An empirical study was conducted by analyzing information system (IS) log data collected from a well-known shipbuilding manufacturer in China. The multiple analytical approach employed in this study includes social network analysis, association rules learning and human dynamics.

Findings

This study first classified IS users into 41 core users and 325 general users. Then 24 core modules and 54 general modules were identified by social network analysis, and the correlation between them was analyzed. Finally, we found that the IS use time intervals for different user groups followed a power-law distribution, and IS use displayed strong burstiness and weak memory.

Originality/value

This study proposes a data-driven perspective to investigate how the system features are actually used in the organization. This study contributes to the literature and opens a new avenue for future IS use research. Furthermore, this study informs managers how to diagnose, maintain and optimize the implemented IS in order to maximize IS benefits.
The interplay of management response and individual power in digital service environments from a bystander's perspective
Authors: Huang Ran , Ha Sejin
Published: April 2020

Purpose

This study aims to investigate bystanders' perceptions and reactions to management responses to consumer complaints through digital service channels. Specific purposes are to examine how management response (i.e. warmth, competence) and individual differences (i.e. bystander power) work together to influence bystanders' information processing of service recovery.

Design/methodology/approach

This research consists of two main studies which employed web-based experiments. Both studies used a 2 (management response: warmth vs competence) × 2 (individual power: low vs high) between-subjects design. A total of 240 participants were recruited from Amazon's Mechanical Turk platform in Study 1, and 233 participants were recruited from a market research company in Study 2.

Findings

Study 1 suggested that for the high-power group, warmth-related responses increased service perceptions (perceived diagnosticity and perceived fairness), and for low-power group, competence-related responses enhanced service perceptions. Study 2 confirmed the results of Study 1 and further demonstrated bystanders' service perceptions as the underlying mechanisms to connect the interactive effect of management response and individual power on satisfaction with complaint handling and WOM intentions.

Practical implications

The current research demonstrates how companies can effectively manage customers' experiences (i.e. bystanders' experiences) with service recovery management on digital platforms by demonstrating effective management responses to consumer complaints through digital service channels.

Originality/value

To the best of our knowledge, this is the first study that explores bystanders' individual characteristics related to the information processing of service recovery through digital service channels.
On the cognitive microfoundations of effectual design: the Situated Function–Behavior–Structure framework
Authors: Emami Amir , Packard Mark D. , Welsh Dianne H.B.
Published: April 2020

Purpose

The purpose of this article is to extend effectuation theory at the front end by building cognitive foundations for the effectual design process.

Design/methodology/approach

We adopt an integrative conceptual approach drawing on design cognition theory to explain entrepreneurial cognition.

Findings

We find a significant gap in the entrepreneurial cognition literature with respect to effectuation processes. We thus integrate the Situated Function–Behavior–Structure framework from design theory to elaborate on the cognitive processes of effectuation, specifically with regard to the opportunity development process. This framework describes the cognitive subprocesses by which entrepreneurs means and ends are cyclically (re)formulated over time until a viable “opportunity” emerges, and the venture is formalized, or else, the entrepreneur abandons the venture and exits.”

Practical implications

Unravelling this entrepreneurial design process may facilitate more appropriate and effective design work by entrepreneurs, leading to more successful product designs. It also should facilitate the development of better design techniques and instruction.

Originality/value

This research contributes to new cognitive foundations for effectuation theory and entrepreneurial process research. It better explains how means are transformed into valuable goods over time through an iterative reconsideration of means-ends frameworks. This theoretical elaboration will expectedly facilitate additional research into the iterative cognitive processes of design and enable more formulaic design thinking.
Mortality and complications after emergency laparotomy in patients above 80 years
Authors: Aakre Elin K. , Ulvik Atle , Hufthammer Karl O. , Jammer Ib
Published: April 2020

Emergency laparotomy (EL) is a high‐risk procedure. However, available evidence regarding outcome after emergency surgery in very old patients is limited. The aim of this observational study was to investigate outcome following EL in patients ≥80 years of age.

Methods

This single‐center retrospective study was undertaken at Haukeland University Hospital, Norway. Demographic data, pre‐operative risk assessment, surgical procedures, intrahospital logistics, complications, mortality, and discharge data were collected from the medical records. Primary outcome was 30‐day mortality. Secondary outcomes were 90‐day mortality, 1‐year mortality, post‐operative complications, and level of care at discharge.

Results

One hundred and six patients aged 80‐96 years underwent EL between 2015 and 2016. Of these, 58% had cardiopulmonary disease, and 16% lived in a nursing home before surgery. Resection of colon was performed in 26 cases, adhesiolysis was performed in 24, and resection of small intestine in 18. Within 30 days, 28 patients died (26%), 15 during the first post‐operative week. For 82% of the patients, at least one complication occurred, and medical complications were far more frequent than surgical. Post‐operatively, pulmonary morbidity was found in 51 patients (48%) and delirium in 42 (40%). The number of intrahospital deaths was 25 (24%). Among the 81survivors, 53 were discharged to a nursing home (65%). One‐year mortality was 47% (50/106).

Conclusions

Mortality after EL in octo‐ and nonagenarians is very high. Medical complications are more common than surgical, and functional decline is frequent. Future studies should focus on the effect of a care bundle including geriatric intervention in these patients.
Quantifying the presence of feral cat colonies and Toxoplasma gondii in relation to bird conservation areas on O'ahu, Hawai'i
Authors: Lepczyk Christopher A. , Haman Katherine H. , Sizemore Grant C. , Farmer Chris
Published: April 2020

Free‐ranging feral cats (Felis catus) are increasingly found in colonies loosely managed by people. These colonies increase cat densities and, hence, pose threats to wildlife via disease and predation, particularly in insular ecosystems where native species have smaller populations and reduced pathogen exposure compared to continental systems. Given such concerns, our objectives were to: (a) identify feral cat colonies on the island of O'ahu in the vicinity of important native bird sites; and (b) test for Toxoplasma gondii, a parasite‐causing disease (Toxoplasmosis) of concern to native birds, at cat colony sites. We identified 32 important native bird locations and surveyed public lands near these sites to determine presence of cat colonies. Where cat colonies were present, we collected feces and used molecular tools to identify the presence of T. gondii. We identified 25 cat colonies near an important bird area and collected feces at four of these colonies, with three testing positive for T. gondii. The presence of cats near a majority of native bird areas suggests that cats may impose a serious threat to bird species. Our finding of T. gondii at three of the four colonies where cat feces were collected raises serious health concerns for humans, birds, and many other terrestrial and aquatic organisms. Native birds in Hawai'i, including highly endangered species, are susceptible to both predation and T. gondii, and finding its presence in locations relatively near to important native bird areas provides further evidence that reducing free‐ranging feral cat numbers is critical for reducing impacts on birds.
Projecting introgression from domestic cats into European wildcats in the Swiss Jura
Authors: Quilodrán Claudio S. , Nussberger Beatrice , Macdonald David W. , Montoya‐Burgos Juan I. , Currat Mathias
Published: April 2020

Hybridization between wild and domesticated organisms is a worldwide conservation issue. In the Jura Mountains, threatened European wildcats (Felis silvestris) have been demographically spreading for approximately the last 50 years, but this recovery is coupled with hybridization with domestic cats (Felis catus). Here, we project the pattern of future introgression using different spatially explicit scenarios to model the interactions between the two species, including competition and different population sizes. We project the fast introgression of domestic cat genes into the wildcat population under all scenarios if hybridization is not severely restricted. If the current hybridization rate and population sizes remain unchanged, we expect the loss of genetic distinctiveness between wild and domestic cats at neutral nuclear, mitochondrial and Y chromosome markers in one hundred years. However, scenarios involving a competitive advantage for wildcats and a future increase in the wildcat population size project a slower increase in introgression. We recommend that future studies assess the fitness of these hybrids and better characterize their ecological niche and their ecological interactions with parental species to elucidate effective conservation measures.
Cardiac and arrhythmic complications in patients with COVID‐19
Authors: Kochi Adriano Nunes , Tagliari Ana Paula , Forleo Giovanni Battista , Fassini Gaetano Michele , Tondo Claudio
Published: April 2020

In December 2019, the world started to face a new pandemic situation, the severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2). Although coronavirus disease (COVID‐19) clinical manifestations are mainly respiratory, major cardiac complications are being reported. Cardiac manifestations etiology seems to be multifactorial, comprising direct viral myocardial damage, hypoxia, hypotension, enhanced inflammatory status, ACE2‐receptors downregulation, drug toxicity, endogenous catecholamine adrenergic status, among others. Studies evaluating patients with COVID‐19 presenting cardiac injury markers show that it is associated with poorer outcomes, and arrhythmic events are not uncommon. Besides, drugs currently used to treat the COVID‐19 are known to prolong the QT interval and can have a proarrhythmic propensity. This review focus on COVID‐19 cardiac and arrhythmic manifestations and, in parallel, makes an appraisal of other virus epidemics as SARS‐CoV, Middle East respiratory syndrome coronavirus, and H1N1 influenza.
The Relationship Between First and Second Language Writing: Investigating the Effects of First Language Complexity on Second Language Complexity in Advanced Stages of Learning
Authors: Ströbel Marcus , Kerz Elma , Wiechmann Daniel
Published: April 2020

Recent studies have uncovered substantial individual differences in first language (L1) language attainment across the lifespan and across multiple components of language. The existence of such variability raises the question of its role in second language (L2) learning. The existing body of research on L1–L2 relationships has primarily targeted reading comprehension by means of controlled experimental designs. This study extended existing research by investigating L1–L2 relationships in writing through the automatic analysis of linguistic complexity in paired samples of authentic production data. For each writing sample, a series of measurements of 12 indicators was obtained using a computational tool that implements a sliding‐window approach. Results from mixed‐effects modeling revealed significant relationships between L1 complexity and L2 complexity for all but one measure, indicating that an L1 effect is robust across different levels of linguistic description.
Is left bundle branch block pattern on the ECG caused by variable ventricular activation sequence?
Authors: Riedlbauchová Lucie , Adla Theodor , Suchánek Vojtěch , Ložek Miroslav , Tomis Jan , Hozman Jiří , Tomek Viktor , Veselka Josef , Janoušek Jan
Published: April 2020

Background

The presence and extent of ventricular dyssynchrony are currently assessed from the QRS complex morphology and width. However, similar electrocardiography (ECG) pattern may be caused by variable ventricular activation sequence. This may then contribute to interindividually different response to cardiac resynchronization therapy (CRT).

Methods

Electroanatomical mapping and magnetic resonance imaging scan were performed in 11 patients with left bundle branch block (LBBB, QRS 170 ± 14 ms) and heart failure of ischemic (coronary artery disease (CAD), n = 2) and nonischemic (dilated cardiomyopathy (DCM), n = 9) etiology. Ventricular activation sequence was studied during LBBB and final CRT programming. Presence and extent of scarring were analyzed in the 17‐segment left‐ventricular (LV) model.

Results

Regardless of etiology, presence of typical LBBB was associated with diffuse prolongation of impulse conduction with right‐to‐left activation sequence. Basal lateral wall was constant site of late activation. This activation pattern was present in “true LBBB,” but also in LBBB‐like pattern (persistent S wave in V5‐6) and left axis deviation. Activation started in right vetricular (RV) apex in patients with left axis deviation at RV free wall in normal axis. Individuals with CAD and DCM patient displayed focal scar. Despite that they exhibited typical LBBB and activation sequence mirrored findings in other LBBB individuals. Reverse remodeling (∆LVESV > 15% after 6 months) was evident in 10 patients.

Conclusions

Both typical LBBB and LBBB‐like pattern might be associated with constant activation sequence regardless of etiology and scar localization. Activation initiation in RV apex, not LV activation sequence can be surrogate for left axis deviation. CRT caused inter‐ and intraventricular LV resynchronization without significantly changed RV activation sequence and duration.
Improved epitaxial growth of TbAs film on III–V semiconductors
Authors: Wang Yuejing , Bork James , Law Stephanie , Zide Joshua M. O.
Published: April 2020

In order to achieve high epitaxial quality of rocksalt TbAs, the authors studied the molecular beam epitaxy growth of TbAs films on zincblende (001) GaAs and (001) InP:Fe wafers. Despite the opposite strain condition of TbAs on these two substrates, mixed-orientation TbAs growth was observed on both substrates. However, the nucleation time and the continuing growth of the TbAs misoriented domains were influenced by the substrate type. By suppressing the growth of misoriented domains in the TbAs film, enhanced single-crystal orientation of TbAs grown on the (001) InP:Fe substrate was observed as compared to the (001) GaAs substrate. In addition, the cube-on-cube epitaxial arrangement of (001) TbAs with a thick film of up to ∼1150 nm is maintained on the (001) InP:Fe substrate but not on the (001) GaAs substrate. The improved TbAs film growth on the InP:Fe substrate exhibited enhanced optical properties when compared to that grown on the GaAs substrate, including a threefold reduction in the scattering rate. This largely improved optical property highlights the importance of increasing the epitaxial quality of TbAs films for future optoelectronic as well as other applications.
Band offsets at amorphous hydrogenated boron nitride/high-k oxide interfaces from x-ray photoelectron spectroscopy with charging effects analysis
Authors: Paquette Michelle M. , Caruso Anthony N. , Brockman Justin , Bielefeld Jeff , Kuhn Markus , King Sean W.
Published: April 2020

To facilitate the design of heterostructure devices employing hexagonal (sp2) boron nitride, x-ray photoelectron spectroscopy has been used to determine the valence band offsets (VBOs) at interfaces between amorphous hydrogenated sp2 boron nitride (a-BN:H) and atomic-layer-deposited high-dielectric-constant (high-k) aluminum oxide (Al2O3) and hafnium oxide (HfO2). After consideration of the effects of charging and differential charging, including with dual-beam charge compensation, the VBOs for Al2O3/a-BN:H and HfO2/a-BN:H interfaces were determined to be 1.9 ± 0.2 and 1.4 ± 0.2 eV, respectively. Additionally, the conduction band offsets at the Al2O3/a-BN:H and HfO2/a-BN:H interfaces were determined, based on literature-reported bandgaps for the respective materials, to be –1.0 ± 0.3 and –1.1 ± 0.3 eV, respectively, indicating type II band alignment in both cases.
Thermal induced depletion of cationic vacancies in NiO thin films evidenced by x-ray absorption spectroscopy at the O 1s threshold
Authors: Gutiérrez Alejandro , Domínguez-Cañizares Guillermo , Krause Stefan , Díaz-Fernández Daniel , Soriano Leonardo
Published: April 2020

The effects of thermal annealing on the concentration of cationic vacancies in p-type semiconducting NiO thin films have been studied by x-ray absorption spectroscopy at the O 1s threshold. This technique proves to be very sensitive to the amount of Ni vacancies through the intensity of a prepeak observed below the absorption threshold, associated with Ni ions in a high oxidation state. Samples with different vacancy concentrations were obtained by radio frequency magnetron sputtering with different O2/Ar ratios in the plasma. Thermal effects have been studied both during thin film growth and after postprocessing annealing. In both cases, the observed effects were very similar, showing a depletion of cationic vacancies with temperature. By changing the surface sensibility of the x-ray absorption spectroscopy measurements, the authors could find out that the transition to stoichiometric NiO begins at the surface.
Metabolic reprogramming and cancer progression
Authors: Faubert Brandon , Solmonson Ashley , DeBerardinis Ralph J.
Published: April 2020

Metabolism as cancer progresses

Numerous cancer-specific alterations in metabolism have been identified but have not yet resulted in an effective anti cancer therapeutic. In a Review, Faubert
et al.
discuss how metabolism changes as cancer develops from a small, premalignant lesion to an aggressive primary tumor and then metastasizes. Metabolic vulnerabilities likely change with cancer progression, making the identification of general cancer-associated metabolic features difficult. The authors propose that a more targeted approach to tissues and vulnerabilities identified in patients may be more effective.

Science
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eaaw5473
Ratcheting quasi-ballistic electrons in silicon geometric diodes at room temperature
Authors: Custer James P. , Low Jeremy D. , Hill David J. , Teitsworth Taylor S. , Christesen Joseph D. , McKinney Collin J. , McBride James R. , Brooke Martin A. , Warren Scott C. , Cahoon James F.
Published: April 2020

Room-temperature electron ratchets

Conventional diodes rectify current flow by forming a junction between dissimilar conductors; a metal-semiconductor diode that forms a Schottky barrier is one example. In these devices, capacitance limits operating frequency. Custer
et al.
describe a diode made entirely of silicon that can rectify currents up to 40 gigahertz at room temperature. They fabricated silicon nanowires with a cylindrical sawtooth profile that act as ratchets, funneling current preferentially in one direction through specular reflection of quasi-ballistic electrons.

Science
, this issue p.
177
A measurement of the wind speed on a brown dwarf
Authors: Allers Katelyn. N. , Vos Johanna M. , Biller Beth A. , Williams Peter. K. G.
Published: April 2020

High winds in an extrasolar atmosphere

Brown dwarfs are objects intermediate in mass between large planets and small stars, and their atmospheres share many characteristics with gas giant planets. Wind speeds in Solar System gas giant atmospheres can be derived by comparing the planet's rotational periods in the infrared (tracing the upper atmosphere) and radio (tied to the interior). Allers
et al.
observed a nearby brown dwarf, 2MASS J10475385+2124234, and determined its infrared and radio periods. They derived an average wind speed of ∼650 meters per second in a west-to-east direction. This technique should also work for exoplanets.

Science
, this issue p.
169
How does the BAPM Framework for Practice on Perinatal Management of Extreme Preterm Birth Before 27 Weeks of Gestation impact delivery of Newborn Life Support? A Resuscitation Council UK response
Authors: Fawke Joe , Tinnion Robert J , Monnelly Victoria , Ainsworth Sean B , Cusack Jonathan , Wyllie Jonathan
Published: April 2020

In October 2019, the British Association of Perinatal Medicine (BAPM) published a Framework1 and associated infographic2 for ‘Practice on Perinatal Management of Extreme Preterm Birth Before 27 Weeks of Gestation’. This outlined an approach, based on data from the UK and abroad, to assist clinicians in decision-making relating to perinatal care at ≤26+6 weeks gestation. Many frontline providers of delivery room care of extremely preterm infants will have completed a Resuscitation Council UK (RCUK) Newborn Life Support or Advanced Resuscitation of the Newborn Infant course. This RCUK response to the BAPM Framework highlights how this might impact on their approach.
Acquired pyroglutamic acidosis due to long-term dicloxacillin and paracetamol use
Authors: Zand Irani Anis , Almuwais Ahmed , Gibbons Holly
Published: April 2020

An 85-year-old man with a background of transfusion-dependent chronic myelomonocytic leukaemia and chronic kidney disease stage III presented with symptomatic anaemia, acute kidney injury, sepsis and high anion gap metabolic acidosis (HAGMA). Initial treatment with intravenous antibiotics and blood transfusion was complicated by transfusion-associated circulatory overload, necessitating diuresis and non-invasive ventilation. Despite gradual clinical improvement, the patient’s HAGMA persisted, and no cause was identified on urine testing or renal ultrasound. As the patient was on long-term dicloxacillin for infective endocarditis prophylaxis and regular paracetamol, pyroglutamic acidosis (PGA) (5-oxoproline acidosis) was considered. This was later confirmed with elevated serum levels, and the HAGMA resolved following cessation of these medications. Although considered an uncommon cause of HAGMA, PGA is likely also under-recognised, and to our knowledge, this may be the second reported case in the context of dicloxacillin.
Increase of a wide range of bioactive substances in an active phase of neuro-Sweet disease
Authors: Kusaka Hiroi , Nagatani Katsuya , Sato Takeo , Minota Seiji
Published: April 2020

We present the case of a patient whose skin findings and human leucocyte antigen (HLA) typing were key findings for the diagnosis of his neuro-Sweet disease. A 55-year-old Japanese man with skin rashes and high fever suddenly developed consciousness disturbance, and brain MRI showed encephalitis and leptomeningitis. Neuro-Behçet disease or microbial infection was initially suspected, but he was eventually diagnosed with neuro-Sweet disease based on his skin rashes and pathology and the presence of HLA-B54 and Cw1. He responded to glucocorticoid and recovered without neurological sequelae. The involvement of cytokines has been implicated in the pathogenesis of Sweet disease, but the number of cytokines assayed in each case report is limited. In our patient’s case, the result of a 27-cytokine assay showed increases in a wide range of bioactive substances including inflammatory cytokines, growth factors and chemoattractants in the active phase, indicating the involvement of multiple cytokines in the pathogenesis of Sweet disease.
The effects of the integration of an economic strengthening and HIV prevention education programme on the prevalence of sexually transmitted infections and savings behaviours among adolescents: a full-factorial randomised controlled trial in South Africa
Authors: Burke Holly M , Chen Mario , Murray Kate , Bezuidenhout Charl , Ngwepe Phuti , Bernholc Alissa , Medina-Marino Andrew
Published: April 2020

Background

Multisectoral approaches are thought necessary to prevent HIV among adolescents. We examined whether an economic strengthening (ES) and an HIV-prevention education intervention improved outcomes when combined versus separately.

Methods

We conducted a full-factorial randomised controlled study to randomise participants into all possible intervention groups based on the two interventions: economic strengthening only (ES-only), HIV-prevention only (HIV-only), both interventions combined (ES+HIV) and no intervention (control). We measured sexually transmitted infections (STIs), self-reported economic and sexual behaviours/knowledge, and pregnancy at a pre-intervention and two post-intervention assessments. Eligible participants were adolescents 14 to 17 years old from a programme supporting vulnerable families in Gauteng Province, South Africa. We estimated intervention effects using repeated measures, generalised linear mixed models.

Results

A total of 1773 adolescents participated (57% female). ES+HIV adolescents had the lowest STI prevalence at first endline; however, the comparison with the control was not significant (OR 0.62, 95% CI 0.27 to 1.41). ES-only or HIV-only groups were not significantly better than the control on STI prevalence (OR 1.53, 95% CI 0.73 to 3.20 and OR 1.47, 95% CI 0.69 to 3.12, respectively). STI prevalence became more similar among the groups at second endline.

ES-only adolescents were more likely to participate in savings groups (p=0.004) and plan to save for education (p=0.001) versus the control. ES+HIV adolescents were more likely to plan to save for education versus the control (p=0.001) and HIV-only groups (p=0.002) but did not differ significantly from the ES-only group (p=0.803). The ES+HIV intervention’s effect on HIV knowledge was significant compared with the control (p=0.03) and ES-only groups (p<0.001), but not when compared with the HIV-only group (p=0.091). Effects on pregnancy, sexual behaviours or other economic behaviours were not significant.

Conclusions

We could not confirm the ES and HIV interventions, separately or combined, were effective to reduce STI prevalence. Evaluations of multicomponent interventions should use full-factorial designs to fully assess effects.

Trial registration number

NCT02888678
Phosphorus supplementation raised the heart rate of male water polo players during a randomised graded dryland exercise test
Authors: Elhusseini Rami , Fares Elie-Jacques , Obeid Omar
Published: April 2020

Objective

The impact of phosphorus supplementation on athletic performance is unclear. Ingestion of phosphorus for several days has been reported to increase cardiac capacity, improve oxygen muscle kinetics and enhance lactate buffering capacity. Recent studies have shown that phosphorus ingestion with a meal increases postprandial glucose uptake and thermogenesis. The present study aimed to assess the effect of acute phosphorus ingestion with a meal on specific workload parameters.

Methods

A double-blind, crossover trial of 12 male water polo players between 18 and 22 years old was conducted. Overnight fasted subjects were asked to cycle for 20 min before ingesting 100 g of glucose with phosphorus or placebo (400 mg). Three hours later, they were asked to perform a graded cycling exercise for 25 min.

Results

Expenditure, respiratory quotient, perception of fatigue and exercise efficiency were similar between treatments. However, heart rate was significantly higher in the phosphorus group (142±10 beats/min) compared with placebo (135±10 beats/min).

Conclusion

Exercise performance 3 hours after the coingestion of glucose with phosphorus did not affect substrate use, while heart rate was increased. The heart rate increase could be attributed to a rise in core body temperature.

Trial registration number

NCT03101215.