bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in the plasmodesma structure and permeability at the bundle sheath and mesophyll interface during the maize C4 leaf development
Authors: Gao Peng , Du Baijuan , Li Pinghua , Kang Byung-Ho
Published: October 2020

Plasmodesmata are intercellular channels that facilitate molecular diffusion between neighboring plant cells. The development and functions of plasmodesmata are controlled by multiple intra- and intercellular signaling pathways. Plasmodesmata are critical for dual-cell C4 photosynthesis in maize because plasmodesmata at the mesophyll and bundle sheath interface mediate exchange of CO2-carrying organic acids. We examined developmental profiles of plasmodesmata and chloroplasts in the maize leaf from young cells in the base to mature cell in the tip using microscopy approaches. Young mesophyll and bundle sheath cells in the leaf base had proplastids, and their plasmodesmata were simple, devoid of cytoplasmic sleeves. In maturing cells where Kranz anatomy and dimorphic chloroplasts were evident, we observed extensive remodeling of plasmodesmata that included acquisition of an electron-dense ring on the mesophyll side and cytoplasmic sleeves on the bundle sheath side. Interestingly, the changes in plasmodesmata involved a drop in symplastic dye mobility and suberin accumulation in the cell wall, implying a more stringent mesophyll-bundle sheath transport. We compared kinetics of the plasmodesmata and the cell wall modification in wildtype leaves with leaves fromppdk and dct2mutants with defective C4 pathways. Plasmodesmata development, symplastic transport inhibition, and cell wall suberization were accelerated in the mutant lines, probably due to the aberrant C4 cycle. Transcriptomic analyses of the mutants confirmed the expedited changes in the cell wall. Our results suggest that a regulatory machinery at the mesophyll-bundle sheath boundary suppresses erroneous flux of C4 metabolites in the maize leaf.

Significance Statement

Plasmodesmata in the maize Kranz anatomy mediate the exchange of organic acids between mesophyll and bundle sheath. Since solute diffusion through plasmodesmata is governed by solute concentration gradients, a balanced distribution of C4 metabolites is critical for concentration of CO2in the bundle sheath. Plasmodesmata bridging the mesophyll and bundle sheath cytoplasm have a cylindrical cavity, which can facilitate molecular movements, and a valve-like attachment. Construction of the sophisticated plasmodesmata was linked to C4 photosynthesis, and plasmodesmata assembly finished more rapidly in maize mutants with defective C4 pathways than in wild-type plants. These results suggest that the specialized plasmodesmata contribute to controlled transport of C4 metabolites.
REEP4 is recruited to the inner nuclear membrane by ELYS and promotes nuclear pore complex formation
Authors: Golchoubian Banafsheh , Brunner Andreas , Bragulat-Teixidor Helena , Akarlar Busra A. , Ozlu Nurhan , Schlaitz Anne-Lore
Published: October 2020

Nuclear pore complexes (NPCs) are channels within the nuclear envelope that mediate nucleocytoplasmic transport. NPCs assemble either into the closed nuclear envelope during interphase or concomitantly with nuclear envelope reformation during anaphase. Both, interphase and post-mitotic NPC biogenesis require local deformation of membrane. Yet, the factors that control proper membrane remodeling for post-mitotic NPC assembly are unknown. Here, we report that the reticulon homology domain-protein REEP4 localizes not only to high-curvature membrane of the cytoplasmic endoplasmic reticulum (ER) but also to the inner nuclear membrane (INM). We show that REEP4 is recruited to the INM by the NPC biogenesis factor ELYS and promotes NPC assembly. REEP4 contributes mainly to anaphase NPC assembly, suggesting that REEP4 has an unexpected role in coordinating nuclear envelope reformation with post-mitotic NPC biogenesis.
Subunit epsilon ofE. coliF1FoATP synthase attenuates enzyme activity by modulating central stalk flexibility
Authors: Sobti Meghna , Walshe James L. , Zeng Yi C. , Ishmukhametov Robert , Stewart Alastair G.
Published: October 2020

F1FoATP synthase functions as a biological rotary generator that makes a major contribution to cellular energy production. Proton flow through the Fomotor generates rotation of the central stalk, inducing conformational changes in the F1motor that catalyzes ATP production via flexible coupling. Here we present a range of cryo-EM structures ofE. coliATP synthase in different rotational and inhibited states observed following a 45 second incubation with 10 mM MgATP. The structures generated describe multiple changes that occur following addition of MgATP, with the inhibitory C-terminal domain of subunit ε (εCTD) disassociating from the central stalk to adopt a condensed “down” conformation. The transition to the εCTD down state increases the torsional flexibility of the central stalk allowing its foot to rotate by ∼50°, with further flexing in the peripheral stalk enabling thec-ring to rotate by two sub-steps in the Fomotor. Truncation mutants lacking the second helix of the εCTD suggest that central stalk rotational flexibility is important for F1FoATP synthase function. Overall this study identifies the potential role played by torsional flexing within the rotor and how this could be influenced by the ε subunit.
Novel Chlamydiae andAmoebophilusendosymbionts are prevalent in wild isolates of the model social amoebaDictyostelium discoideum
Authors: Haselkorn Tamara S. , Jimenez Daniela , Bashir Usman , Sallinger Eleni , Queller David C. , Strassmann Joan E. , DiSalvo Susanne
Published: October 2020

Amoebae interact with bacteria in diverse and multifaceted ways. Amoeba predation can serve as a selective pressure for the development of bacterial virulence traits. Bacteria may also adapt to life inside amoebae, resulting in symbiotic relationships (pathogenic or mutualistic). Indeed, particular lineages of obligate bacterial endosymbionts have been found in different amoebae. Here, we screened an extensive collection ofDictyostelium discoideumwild isolates for the presence of such bacterial symbionts using PCR primers that identify these endosymbionts. This is the first report of obligate symbionts in this highly-studied amoeba species. They are surprisingly common, identified in 42% of screened isolates (N=730). Members of the Chlamydiae phylum are particularly prevalent, occurring in 27% of the host strains. They are novel and phylogenetically distinct. We also foundAmoebophilussymbionts in 8% of screened isolates (N=730). Antibiotic-cured amoebae behave similarly to their endosymbiont-infected counterparts, suggesting that endosymbionts do not significantly impact host fitness, at least in the laboratory. We found several natural isolates were co-infected with multiple endosymbionts, with no obvious fitness effects of co-infection under laboratory conditions. The high prevalence and novelty of amoeba endosymbiont clades in the model organismD. discoideumopens the door to future research on the significance and mechanisms of amoeba-symbiont interactions.
TheGiardia lambliaribosome structure reveals divergence in translation and quality control pathways
Authors: Eiler Daniel R. , Wimberly Brian T. , Bilodeau Danielle Y. , Rissland Olivia S. , Kieft Jeffrey S.
Published: October 2020

Giardia lambliais a human pathogen of worldwide importance with limited treatment options. Its unusual molecular biology presents targets for new therapies and the opportunity to explore the fundamental features of important biological mechanisms. We determined the structure of theG. lamblia80S ribosome by cryoelectron microscopy, revealing how it combines eukaryotic and bacterial features. The structure reveals regions that are rapidly evolving, including depletion of A and U bases from its rRNA. Specific features of theG. lambliaribosome suggest it is less prone to stall on problematic peptide sequences, and that the organism uses altered ribosome quality control pathways compared to other eukaryotes. Examination of translation initiation factor binding sites suggests these interactions are conserved despite a divergent initiation mechanism. This work defines key new questions regarding ribosome-centric biological pathways inG. lambliaand motivates new experiments to explore potential targetable mechanisms.
Social relationships among captive male pygmy slow lorises (Nycticebus pygmaeus): Is forming male same-sex pairs a feasible management strategy?
Authors: Yamanashi Yumi , Nemoto Kei , Alejandro Josue
Published: October 2020

Little is known about the social behavior of pygmy slow lorises, in particular, the social relationships of same-sex individuals have rarely been investigated. The Slow Loris Conservation Center was built at the Japan Monkey Center to enhance the welfare of confiscated slow lorises, promote their conservation, improve public education and perform scientific research on the species. In the course of improving housing conditions, several same-sex pairs of pygmy slow lorises were formed. We monitored their behaviors and fecal glucocorticoid metabolite (FGM) levels to understand whether male same-sex pairings could be a feasible management strategy. The subjects were 10 male and 6 female lorises for comparison, all of whom were over five years old. We successfully formed five pairs of male lorises after eight formation attempts. Male pairs initially showed some aggressive behaviors; however, the rate decreased approximately 10 days after introduction. All of the male pairs eventually exhibited extensive affiliative social behaviors, including allogrooming and social play, during the dark (active) phase, and sleep site sharing during the light (inactive) phase. The rate of sleep site sharing during the light phase was higher than expected, suggesting that the pairs preferred to stay near each other. There was no evidence of increased stress after a long period of male–male social housing. Female same-sex pairs and male-female pairs demonstrated a high level of affiliative behaviors right after introduction. These results highlight the flexibility and high sociability of this species and indicate that such same-sex pairings are a feasible option for their social management.
Polyamines Mediate Folding of Primordial Hyper-Acidic Helical Proteins
Authors: Despotović Dragana , Longo Liam M. , Aharon Einav , Kahana Amit , Scherf Tali , Gruic-Sovulj Ita , Tawfik Dan S.
Published: October 2020

Polyamines are known to mediate diverse biological processes, and specifically to bind and stabilize compact conformations of nucleic acids, acting as chemical chaperones that promote folding by offsetting the repulsive negative charges of the phosphodiester backbone. However, whether and how polyamines modulate the structure and function of proteins remains unclear. Further, early proteins are thought to have been highly acidic, like nucleic acids, due to a scarcity of basic amino acids in the prebiotic context. Perhaps polyamines, the abiotic synthesis of which is simple, could have served as chemical chaperones for such primordial proteins? We replaced all lysines of an ancestral 60-residue helix-bundle protein to glutamate, resulting in a disordered protein with 21 glutamates in total. Polyamines efficiently induce folding of this hyper-acidic protein at sub-millimolar concentrations, and their potency scaled with the number of amine groups. Compared to cations, polyamines were several orders of magnitude more potent than Na+, while Mg2+and Ca2+had an effect similar to a di-amine, inducing folding at approximately seawater concentrations. We propose that (i) polyamines and dications may have had a role in promoting folding of early proteins devoid of basic residues, and that (ii) coil-helix transitions could be the basis of polyamine regulation in contemporary proteins.
Regulation of kinase activity by combined action of juxtamembrane and C-terminal regions of receptors
Authors: Lin Chi-Chuan , Wieteska Lukasz , Poncet-Montange Guillaume , Suen Kin M. , Arold Stefan T. , Ahmed Zamal , Ladbury John E.
Published: October 2020

Despite the kinetically-favorable, ATP-rich intracellular environment, the mechanism by which receptor tyrosine kinases (RTKs) repress activation prior to extracellular stimulation is poorly understood. RTKs are activated through a precise sequence of phosphorylation reactions starting with a tyrosine on the activation loop (A-loop) of the intracellular kinase domain (KD). This forms an essential mono-phosphorylated ‘active intermediate’ state on the path to further phosphorylation of the receptor. We show that this state is subjected to stringent control imposed by the peripheral juxtamembrane (JM) and C-terminal tail (CT) regions. This entails interplay between the intermolecular interaction between JM with KD, which stabilizes the asymmetric active KD dimer, and the opposing intramolecular binding of CT to KD. A further control step is provided by the previously unobserved direct binding between JM and CT. Mutations in JM and CT sites that perturb regulation are found in numerous pathologies, revealing novel sites for potential pharmaceutical intervention.
Growth of Saccharomyces cerevisiae and Preparation of DNA
Authors: Heintz Nathaniel , Gong Shiaoching
Published: October 2020

This protocol describes methods for isolation of total DNA from a strain of Sacchromyces cerevisiae carrying a recombinant yeast artificial chromosome (YAC). This method is appropriate for preparing DNA that will be subjected to regular agarose gel electrophoresis, Southern blotting, subcloning, genomic library construction, polymerase chain reaction (PCR), or other methods that do not require intact high-molecular-weight DNA. Because the linear YAC DNAs are sensitive to shearing forces, pipettes with wide-bore tips should be used to transfer DNAs. Drop dialysis should be used to exchange buffers. The expected yield from a 10-mL culture is 2–4 µg of yeast DNA.
Collecting and Storing Hybridoma Tissue Culture Supernatants
Authors: Greenfield Edward A.
Published: October 2020

For most immunochemical methods, tissue culture supernatants will be the most useful source of monoclonal antibodies. The supernatants are not contaminated with high levels of other antibodies, and the concentration is high enough for most assays if used undiluted. This protocol describes the procedure of collecting tissue culture supernatants. When collecting supernatants for antibodies, allow the individual cultures to grow until the hybridomas die. This will allow collection of higher-titer supernatants. In general, antibodies are resistant to the proteases that are released from dying cells, so allowing the cells to die should not affect the quality of the antibodies. If extraneous IgG molecules will alter any of the assays for which the supernatants are being prepared, use medium with fetal bovine serum or use serum-free medium. The yield of this method is ∼20–50 µg of antibody/mL of supernatant. The most common problem encountered in storage of tissue culture supernatants after collection is contamination with bacteria or fungi. This can be prevented by the addition of sodium azide as described.
Animal Maintenance Systems: Xenopus laevis
Authors: Shaidani Nikko-Ideen , McNamara Sean , Wlizla Marcin , Horb Marko E.
Published: October 2020

Modular recirculating animal aquaculture systems incorporate UV sterilization and biological, mechanical, and activated carbon filtration, creating a nearly self-contained stable housing environment for Xenopus laevis. Nonetheless, minimal water exchange is necessary to mitigate accumulation of metabolic waste, and regular weekly, monthly, and yearly maintenance is needed to ensure accurate and efficient operation. This protocol describes the methods for establishing a new recirculating system and the necessary maintenance, as well as water quality parameters, required for keeping Xenopus laevis.
Temporal Regulation of the Metabolome and Proteome in Photosynthetic and Photorespiratory Pathways Contributes to Maize Heterosis
Authors: Li Zhi , Zhu Andan , Song Qingxin , Chen Helen Y. , Harmon Frank G. , Chen Z. Jeffrey
Published: October 2020

Heterosis or hybrid vigor is widespread in plants and animals. Although the molecular basis for heterosis has been extensively studied, metabolic and proteomic contributions to heterosis remain elusive. Here we report an integrative analysis of time-series metabolome and proteome data in maize (Zea mays) hybrids and their inbred parents. Many maize metabolites and proteins are diurnally regulated, and many of these show nonadditive abundance in the hybrids, including key enzymes and metabolites involved in carbon assimilation. Compared with robust trait heterosis, metabolic heterosis is relatively mild. Interestingly, most amino acids display negative mid-parent heterosis (MPH), i.e., having lower values than the average of the parents, while sugars, alcohols, and nucleoside metabolites show positive MPH. From the network perspective, metabolites in the photosynthetic pathway show positive MPH, whereas metabolites in the photorespiratory pathway show negative MPH, which corresponds to nonadditive protein abundance and enzyme activities of key enzymes in the respective pathways in the hybrids. Moreover, diurnally expressed proteins that are upregulated in the hybrids are enriched in photosynthesis-related gene-ontology terms. Hybrids may more effectively remove toxic metabolites generated during photorespiration, and thus maintain higher photosynthetic efficiency. These metabolic and proteomic resources provide unique insight into heterosis and its utilization for high yielding maize and other crop plants.
Multiple logics within the international Islamic financial architecture: implications for Islamic financial reporting standards
Authors: Mukhlisin Murniati , Fadzly Mohamed
Published: October 2020

Purpose

This paper aims to examine the existence of multiple institutional logics among a number of organisations within the international Islamic financial architecture (IIFA) whose main purpose is to promote and support the development of Islamic financial institutions (IFIs) across the globe and how IIFA relates to the role of Islamic financial reporting standards.

Design/methodology/approach

The authors review websites of 11 IIFA’s constituent organisations and undertake 7 in-depth, semi-structured interviews with senior members of a selection of these organisations to identify the dominant logics by which their role and (inter)action within the IIFA are shaped.

Findings

The study findings reveal evidence of competing (and shifting) logics and political interests that seem to have led to contradictions and inconsistencies among the constituent organisations. The authors explain this by proposing a framework consisting of religion logic, market logic and corporate logic that intertwines with the underlying economic system and acts as sources of identity–legitimacy–authority for the respective organisations.

Originality/value

The authors bring to light some key issues that may pose a threat to the sustained existence of IFIs. The authors adapt the institutional logic framework and incorporate it into religion logic within the context of Islam (i.e. hifdzul-din as the first Maqasid ul-Shari’ah), resulting in some fresh theoretical perspective that may inform future research.
Motor imagery-based EEG signals classification by combining temporal and spatial deep characteristics
Authors: Xiaoling Li
Published: October 2020

Purpose

In order to improve the weak recognition accuracy and robustness of the classification algorithm for brain-computer interface (BCI), this paper proposed a novel classification algorithm for motor imagery based on temporal and spatial characteristics extracted by using convolutional neural networks (TS-CNN) model.

Design/methodology/approach

According to the proposed algorithm, a five-layer neural network model was constructed to classify the electroencephalogram (EEG) signals. Firstly, the author designed a motor imagery-based BCI experiment, and four subjects were recruited to participate in the experiment for the recording of EEG signals. Then, after the EEG signals were preprocessed, the temporal and spatial characteristics of EEG signals were extracted by longitudinal convolutional kernel and transverse convolutional kernels, respectively. Finally, the classification of motor imagery was completed by using two fully connected layers.

Findings

To validate the classification performance and efficiency of the proposed algorithm, the comparative experiments with the state-of-the-arts algorithms are applied to validate the proposed algorithm. Experimental results have shown that the proposed TS-CNN model has the best performance and efficiency in the classification of motor imagery, reflecting on the introduced accuracy, precision, recall, ROC curve and F-score indexes.

Originality/value

The proposed TS-CNN model accurately recognized the EEG signals for different tasks of motor imagery, and provided theoretical basis and technical support for the application of BCI control system in the field of rehabilitation exoskeleton.
The dependence structure and portfolio risk of Malaysia's foreign exchange rates: the Bayesian GARCH–EVT–copula model
Authors: Yeap Xiu Wei , Lean Hooi Hooi , Sampid Marius Galabe , Mohamad Hasim Haslifah
Published: October 2020

Purpose

This paper investigates the dependence structure and market risk of the currency exchange rate portfolio from the Malaysian ringgit perspective.

Design/methodology/approach

The marginal return of the five major exchange rates series, i.e. United States dollar (USD), Japanese yen (JPY), Singapore dollar (SGD), Thai baht (THB) and Chinese Yuan Renminbi (CNY) are modelled by the Bayesian generalized autoregressive conditional heteroskedasticity (GARCH) (1,1) model with Student's t innovations. In addition, five different copulas, such as Gumbel, Clayton, Frank, Gaussian and Student's t, are applied for modelling the joint distribution for examining the dependence structure of the five currencies. Moreover, the portfolio risk is measured by Value at Risk (VaR) that considers the extreme events through the extreme value theory (EVT).

Findings

The finding shows that Gumbel and Student's t are the best-fitted Archimedean and elliptical copulas, for the five currencies. The dependence structure is asymmetric and heavy tailed.

Research limitations/implications

The findings of this paper have important implications for diversification decision and hedging problems for investors who involving in foreign currencies. The authors found that the portfolio is diversified with the consideration of extreme events. Therefore, investors who are holding an individual currency with VaR higher than the portfolio may consider adding other currencies used in this paper for hedging.

Originality/value

This is the first paper estimating VaR of a currency exchange rate portfolio using a combination of Bayesian GARCH model, EVT and copula theory. Moreover, the VaR of the currency exchange rate portfolio can be used as a benchmark of the currency exchange market risk.
Predictive data analytics for contract renewals: a decision support tool for managerial decision-making
Authors: Simsek Serhat , Albizri Abdullah , Johnson Marina , Custis Tyler , Weikert Stephan
Published: October 2020

Purpose

Predictive analytics and artificial intelligence are perceived as significant drivers to improve organizational performance and managerial decision-making. Hiring employees and contract renewals are instances of managerial decision-making problems that can incur high financial costs and long-term impacts on organizational performance. The primary goal of this study is to identify the Major League Baseball (MLB) free agents who are likely to receive a contract.

Design/methodology/approach

This study used the design science research paradigm and the cognitive analytics management (CAM) theory to develop the research framework. A dataset on MLB's free agents between 2013 and 2017 was collected. A decision support tool was built using artificial neural networks.

Findings

There are clear links between a player's statistical performance and the decision of the player to sign a new offered contract. “Age,” “Wins above Replacement” and “the team on which a player last played” are the most significant factors in determining if a player signs a new contract.

Originality/value

This paper applied analytical modeling to personnel decision-making using the design science paradigm and guided by CAM as the kernel theory. The study employed machine learning techniques, producing a model that predicts the probability of free agents signing a new contract. Also, a web-based tool was developed to help decision-makers in baseball front offices so they can determine which available free agents to offer contracts.
Knowledge management as a driver of performance in ambulatory healthcare – a systematic literature review through an intellectual capital lens
Authors: Pflugfelder Nina S.
Published: October 2020

Purpose

The purpose of this study is to investigate how Knowledge Management (KM) and Intellectual Capital (IC) can increase the organizational performance of ambulatory healthcare providers and how such performance can be assessed.

Design/methodology/approach

Following the PRISMA guidelines, a structured review of peer-reviewed English-speaking articles up to 31stDecember 2019 was conducted. A search of ACM Digital Library, Cochrane Library, DARE, EBSCOHost, Medline, ProQuest, PubMed, ScienceDirect, Scopus and Web of Science produced 8,391 results. All studies that did not examine the impact of KM initiatives on organizational performance in an ambulatory healthcare provider setting were eliminated. The final sample of 31 studies was examined regarding the design of the KM initiatives as well as the performance concepts and indicators employed.

Findings

A range of KM tools and methods (Electronic Health Records, Clinical Decision Support, Health Information Technology, Training, Communities of Practice) have been shown to improve healthcare processes but evidence of an impact on outcomes remains mixed. Performance indicators focus on medical quality but rarely capture economic or social performance. Indicators have been adapted from the medical field, but do not adequately capture IC and KM-induced performance.

Originality/value

This review provides an overview of KM initiatives in ambulatory healthcare and assesses the associated performance metrics through an IC lens. Thereby, it enables further research on the interplay of IC, KM and performance in ambulatory care and points to several research gaps. It provides managers with guidance for designing KM initiatives in their organizations
Hybrid intelligent vehicle system for managing construction supply chain in precast concrete building construction projects
Authors: Ismail Zul-Atfi Bin
Published: October 2020

Purpose

While the adversarial nature of precast concrete (PC) building construction is frequently cited in the PC building construction press, only a few researchers have investigated construction supply chain management within the construction industry. Due to the interdisciplinary transportation environment, which inevitably results in disruption, the uses of construction supply chain and recovery from construction supply chain risk must be a subject of real interest, yet transportation management research in this area is scarce.

Design/methodology/approach

The purpose of this study is to discuss the weakness in system approaches and their application for managing precast concrete building in the context of construction supply chain practice and how to overcome it. As a precursor to this paper, the paper reviews current construction supply chain management occurrence on PC building construction and explores the hybrid intelligent vehicle tools and techniques currently being used on such management. This paper also presents the new hybrid intelligent vehicle-based approach to manage construction supply chain risk and reduce associated tension on PC building construction schemes.

Findings

The findings reveal the need for more sophisticated construction supply chain management solutions which accord with the needs of PC building construction schemes.

Originality/value

The paper concludes by presenting a research framework for developing such a system in the future.
A fungal scent from the cheese
Authors: Kovács Ákos T.
Published: October 2020

Assembly of microbial communities is shaped by various physical and chemical factors deriving from their environment, including other microbes inhabiting the certain niche. In addition to direct cell–cell contacts, primary and secondary metabolites impact the growth of microbial community members. Metabolites might act as growth‐promoting (e.g., cross‐feeding), growth‐inhibiting (e.g., antimicrobials) or signalling molecules. In multi‐species microbial assemblies, secreted metabolites might influence specific members of the community, altering species abundances and therefore the functioning of these microcosms. In the current issue, Cosetta and colleagues describe a unique volatile metabolite‐mediated cross‐kingdom interaction that shapes the cheese rind community assembly. The study paves the way of our understanding how fungus‐produced volatile compounds promote the growth of a certain bacterial genus, a principal connection between community members of the cheese rind.
State effectiveness, property rights and entrepreneurial behaviour as determinants of National Innovation
Authors: Idrees Alvina Sabah , Sarwar Saima
Published: October 2020

This article examines the role of entrepreneurial behaviour, property rights and state effectiveness as determinants of national innovation. Entrepreneurial behaviour reflects not only risk‐bearing and risk‐sharing attitudes but also the capacity to undertake innovation activities. Besides, institutions also play an important role in formalising entrepreneurial behaviour that is crucial for a country's innovation. A comparison is made among three groups of countries—that is, factor‐driven, efficiency‐driven and innovation‐driven economies. Panel‐data econometric techniques are applied to undertake empirical analysis, using macro‐level data covering a time period of 7 years (2010–2016). It is observed that entrepreneurial attitudes and entrepreneurial activities play an important role in determining innovation but the impact varies with the level of economic development. A U‐shaped relationship is observed between innovation and entrepreneurial activities. Innovation‐driven economies have strong property rights and effective policy implementation that help build the confidence of prospective entrepreneurs who are attracted by perceived opportunities. Therefore, perceived opportunities have a significant impact only in innovation‐driven economies. Moreover, innovation is highly suppressed in fragile countries, that is, factor‐driven economies that face serious market distortions and inefficiencies caused by weak property rights and state ineffectiveness. However, no significant relationship is found in efficiency‐driven economies.
Changes in health insurance coverage, access to care, and health services utilization by sexual minority status in the United States, 2013‐2018
Authors: Gonzales Gilbert , Henning‐Smith Carrie , Ehrenfeld Jesse M.
Published: October 2020

Objective

To examine the changes in health insurance coverage, access to care, and health services utilization among nonelderly sexual minority and heterosexual adults between pooled years 2013‐2014 and 2017‐2018.

Data Sources

Data on 3223 sexual minorities (lesbians, gay men, bisexual individuals, and other nonheterosexual populations) and 86 181 heterosexuals aged 18‐64 years were obtained from the 2013, 2014, 2017, and 2018 National Health Interview Surveys.

Study Design

Unadjusted and regression‐adjusted estimates compared changes in health insurance status, access to care, and health services utilization for nonelderly adults by sexual minority status. Regression‐adjusted changes were obtained from logistic regression models controlling for demographic and socioeconomic characteristics.

Principal Findings

Uninsurance declined for both sexual minority adults (5 percentage points, P < .05) and heterosexual adults (2.5 percentage points, P < .001) between 2013‐2014 and 2017‐2018. Reductions in uninsurance for sexual minority and heterosexual adults were associated with increases in Medicaid coverage. Sexual minority and heterosexual adults were also less likely to report unmet medical care in 2017‐2018 compared with 2013‐2014. Low‐income adults (regardless of sexual minority status) experienced relatively large increases in Medicaid coverage and substantial improvements in access to care over the study period. The gains in coverage and access to care across the study period were generally similar for heterosexual and sexual minority adults.

Conclusions

Sexual minority and heterosexual adults have experienced improvements in health insurance coverage and access to care in recent years. Ongoing health equity research and public health initiatives should continue to monitor health care access and the potential benefits of recent health insurance expansions by sexual orientation and sexual minority status when possible.
Mechanical properties of glass‐fibre‐reinforced composite posts after laser irradiation with different energy densities
Authors: Kırmalı Ömer , Akçakuş Battal Tuba , Turker Nurullah , Dündar Ayşe
Published: October 2020

The aim of the present study was to evaluate the effect of the surface treatments on flexural strengths and flexural modulus of glass‐fibre‐reinforced composite (GFRC) posts. Sixty‐three posts were randomly divided into 9 groups (n = 7), and various surface treatments were performed. The control group was left untreated. Other groups were treated with 9% hydrofluoric acid, sandblasting with 120 µm Al2O3 particles and Er,Cr:YSGG laser irradiation with different powers (1 W, 2 W, 3 W, 4 W, 5 W and 6 W). The samples were subjected to 3‐point bending test, and data were calculated. Statistical analysis was performed. The flexural strengths of fibre posts treated with sandblasting, hydrofluoric acid, 1 W and 2 W laser were statistically similar with control group (P > 0.01). However, the flexural strength of fibre posts treated with 3 W, 4 W, 5 W and 6 W laser was statistically lower than control group (P < 0.01). High laser irradiations cause melting on the post surface and breaks in fibrils.
Histo‐ontogenetic study of the parotid salivary gland of Indian buffalo
Authors: Singh Amandeep , Singh Opinder
Published: October 2020

The present study was aimed at elucidating the histogenesis of parotid gland of buffalo. The study was carried out on buffalo foetuses (n = 36), during different stages of prenatal life. The foetuses were categorised into three groups based on their curved crown rump length (CVRL). The primordial anlage of parotid salivary gland was evident at 40th day of development whereas the primary ducts, in the form of cords, were first observed at 81st day of prenatal life. The capsule formation as well as the lobulation of the gland was initiated at 127th day. At 141st day, the duct system of gland was completed. The terminal tubules attained the structure of acini at 167th day. The myoepithelial cells first appeared as flattened basal cells initially around the developing acinar cells at 167th day. The typical compound tubulo‐acinar nature of the gland was first observed at 185th day. Purely serous acinar cells were seen from 185th day onwards. The micrometrical studies revealed that the mean diameter of acinar cells, intercalated ducts, striated ducts and large ducts increased with the advancement of age. The serous acinar cells were devoid of acidic as well as neutral mucopolysaccharides in prenatal age groups; however, large ducts with goblet cells exhibited positive reaction. Combined PAS‐AB method revealed mixed reaction in acinar cells as well as in large ducts. Fine lipid droplets were observed in intralobular as well as interlobular connective tissue; however, phospholipids were observed in the cell membrane of secretory cells and ducts.
Long‐term changes in population size and the age structure and sex ratio of waterbuck in a Sudanian savannah of Burkina Faso
Authors: Konate Sidiki , Sirima Djidama , Ardjima Lankoande , Sanou Youssouf , Hema Emmanuel M. , Kabre B. Gustave , Fa Julia E. , Luiselli Luca , Petrozzi Fabio
Published: October 2020

The waterbuck (Kobus ellipsiprymnus), though widespread throughout Africa, is suspected to be declining overall. Data on population numbers and structure are lacking for many parts of its range, especially in West Africa, where the subspeciesdefassais found. The aim of the present study was to evaluate the abundance, distribution and attributes of waterbuck populations from the Nazinga Forest Reserve, southern Burkina Faso. We investigated waterbuck population trends in the park using transect data collected in 1985–2019. For the more detailed analyses of population structure and distribution of the animals, we used census data gathered during 2019. Most animals were adults (46.6%), and the sex ratio was heavily skewed towards females (5:1). Most animals were concentrated along the larger rivers. There was no influence of poacher activity on waterbuck distribution. In the long term (1985–2019), the population dynamics of waterbuck can be roughly divided into two main periods: a phase of population increase from 1985 to 2005, and one of ongoing population collapse from 2007 to 2019. Although the declining population trend was obvious, coefficients of determination were low indicating that the years explained poorly the number of individuals and the number of sightings obtained. Waterbuck numbers in the Nazinga Forest Reserve are declining, but we found no single reason to explain this trend. It is likely that a combination of factors, including global warming (increased aridity) and illegal activities such as poaching, is responsible. Because there are probably multiple reasons for the observed waterbuck population decline in our study area, we suggest that a multifaceted approach should be adopted in order to enhance the conservation status of the local waterbuck populations.
Experimental investigation of right‐left flow balance concepts for a total artificial heart
Authors: Diedrich Mario , Hildebrand Stephan , Lommel Moritz K. , Finocchiaro Thomas , Cuenca Elena , De Ben Heiko , Schmitz‐Rode Thomas , Steinseifer Ulrich , Jansen Sebastian
Published: October 2020

A total artificial heart (TAH) must be designed to autonomously balance the flows of the systemic and pulmonary circulation to prevent potentially lethal lung damage. The flow difference between the systemic and pulmonary circulation is mainly caused by the bronchial (arteries) shunt flow and can change dynamically. The ReinHeart TAH consists of only one actuator that ejects blood alternately from the right and left pump chamber. This design entails a coupling of the right and left stroke and thus, complicates the independent adaptation of the right and left flow. In this experimental study on the ReinHeart TAH, four concepts to keep the flows well balanced were investigated using an active mock circulation loop for data acquisition. Three concepts are based on mechanical design changes (variation of pusher plate shape, flexible right pump chamber housing, and reduced right stroke volume) to achieve a static flow difference. In combination with these static concepts, a concept influencing the ratio of systole and diastole duration to respond to dynamic changes was studied. In total, four measurement series, each with 270 operating points, to investigate the influence of circulatory filling volume, heart rate, bronchial shunt flow, and lung resistance were recorded. In the course of this study, we introduce a concept deviation indicator, providing information about the efficiency of the concepts to balance the flows based on changes in lung’s blood pressures. Furthermore, the distribution of the measured data was evaluated based on bubble plot visualizations. The investigated variation of the right pusher plate shape results in high lung pressures which will cause lethal lung damage. In comparison, a flexible right pump chamber housing shows lower lung pressures, but it still has the potential to damage the lungs. Reducing the stroke volume of the right pump chamber results in proper lung pressures. The flow balance can dynamically be influenced with a positive effect on the lung pressures by choosing a suitable systole‐diastole‐ratio. The results of this study suggest that an adequate right‐left flow balance can be achieved by combining the mechanical concept of a reduced right stroke volume with an active control of the systole‐diastole‐ratio.
Heart transplant waiting list implications of increased ventricular assist device use as a bridge strategy: A national analysis
Authors: Han Jason J. , Elzayn Hadi , Duda Matthew M. , Iyengar Amit , Acker Andrew M. , Patrick William L. , Helmers Mark , Birati Edo Y. , Atluri Pavan
Published: October 2020

The use of ventricular assist devices (VADs) as a bridge to heart transplant (HT) is increasing, while HT volume remains stagnant. This may portend longer waiting times and an otherwise more competitive environment for all patients on the HT waiting list. A retrospective analysis of patients who were listed for HT in the United Network for Organ Sharing (UNOS) database from 2000 to 2015 was conducted. Mean waiting time, proportion of HT reception (%HT), proportion of death (%death), and proportion of waiting list removal (%removal) were calculated across three eras: Era 1 (2000‐2007), Era 2 (2008‐2011), and Era 3 (2012‐2015). During the study period, 29 728 patients successfully underwent HT. 19 127 (64.3%) were directly transplanted (direct HT); 4491 (15.1%) received VADs prior to listing as a bridge to decision (BTD); and 4593 (15.5%) received VADs after listing as a bridge to transplant (BTT). Across the three eras, the average number of registrants per year grew. Among all groups, waiting time increased across the eras. %HT generally decreased in the BTD and BTT groups but remained constant in the direct HT group. %removal increased, while %death decreased in all group across the eras. Waiting time for HT increased from 2000 to 2015. Patients with VADs as a bridge strategy experienced decreasing %HT and increasing %removal but stable survival. Improvements in VAD safety and durability will ensure their success as part of a bridge strategy to HT under the new UNOS allocation policy.
Re‐endothelialization of non‐detergent decellularized porcine vessels
Authors: Eyre Katerina , Samper Esther , Haverich Axel , Hilfiker Andres , Andrée Birgit
Published: October 2020

Tissue engineering utilizes an interdisciplinary approach to generate constructs for the treatment and repair of diseased organs. Generation of small vessels as vascular grafts or as envisioned central vessel for vascularized constructs is still a challenge. Here, the decellularization of porcine vessels by a non‐detergent based protocol was developed and investigated. Perfusion‐decellularization with sodium hydroxide solution resulted in removal of cellular material throughout the whole length of the vessel while preserving structural and mechanical integrity. A re‐endothelialization of the retrieved matrix with human umbilical vein endothelial cells and cardiac endothelial cells was achieved through rotation‐based seeding employing a custom‐made bioreactor. A confluent monolayer was detected on the entire luminal surface. Thus, a non‐detergent‐based decellularization method allowing the re‐endothelialization of the luminal surface was developed in this study, thereby paving the way for future implementation of the resulting construct as vascular graft or as central vessel for tissue engineered constructs in need of a perfusion system with readily available anastomosis sites.
Strategic encoding and retrieval processes in verbal recall among middle‐aged and older adults
Authors: Cherry Katie E. , Elliott Emily M. , Golob Edward J. , Brown Jennifer Silva , Kim Sangkyu , Jazwinski S. Michal
Published: October 2020

The authors used an analysis of individual differences to examine the role of executive control in strategic encoding and retrieval in verbal recall. Participants enrolled in the Louisiana Healthy Aging Study completed measures of working memory (WM), cognitive status, vocabulary, and free recall of words. Indices of clustering in free recall were calculated to permit inferences on strategic encoding and retrieval processes. We hypothesized that WM would be more strongly associated with strategic encoding and retrieval metrics than vocabulary based on the assumption that successful remembering requires executive control in WM. Regression analyses, together with a variance portioning procedure, confirmed that WM had comparable levels of unique and shared variance with the strategic encoding and retrieval metrics, and both exceeded vocabulary. Theoretical and clinical implications of these data are considered, with the suggestion of future research in lifespan samples as opposed to exclusively young adult or older adult samples.
Simulated chorus attracts conspecific and heterospecific Amazonian explosive breeding frogs
Authors: Fouquet Antoine , Tilly Thomas , Pašukonis Andrius , Courtois Elodie A. , Gaucher Philippe , Sebastian Ulloa Juan , Sueur Jérôme
Published: October 2020

In tropical regions, some anuran species breed "explosively", reproducing in massive and highly diverse aggregations during a brief window of time. These aggregations can serve as acoustic beacons, attracting other anurans toward seasonal ponds. We hypothesize that conspecific and heterospecific calls play a role in navigation toward ponds and synchronization of reproduction among species. We simulated a chorus of two species (Trachycephalus coriaceus and Chiasmocleis shudikarensis) with contrasting call characteristics (low‐frequency vs. high‐frequency) and reproductive strategies (strict pond breeder vs. opportunistic) near known explosive breeding sites. We predicted that choruses of T. coriaceus are more attractive to heterospecifics than of C. shudikarensis because the first provides a more reliable indicator of a suitable breeding pond and a better long‐distance signal. We found that both choruses attracted conspecific frogs to the playback outside a natural breeding event. As predicted, heterospecifics were attracted only by low‐frequency calls of T. coriaceus that breeds exclusively in large ponds, but not by higher frequency calls of C. shudikarensis that also breeds in small pools not suitable for other species. Our study presents the first experimental evidence that tropical explosive breeding anurans are attracted to conspecific and heterospecific choruses. The contrasting effect of the playback of the two species on heterospecifics suggests that the attractive effect of a chorus depends on the reproductive strategy of both the sender and the receiver. Given the abundance and diversity of communities in tropical ecosystems, the use of heterospecific acoustic cues may prove widespread and requires further investigation.

Abstract in Portuguese is available with online material.