bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatiotemporal single cell transcriptomic analysis of human gut macrophages reveals multiple functional and niche-specific subsets
Authors: Domanska Diana , Majid Umair , Karlsen Victoria T. , Merok Marianne A. , Beitnes Ann-Christin , Yaqub Sheraz , Bækkevold Espen S. , Jahnsen Frode L. 
Published: May 2021

AbstractMacrophages are a heterogeneous population of cells involved in tissue homeostasis, inflammation and cancer. Although macrophages are densely distributed throughout the human intestine, our understanding of how gut macrophages maintain tissue homeostasis is limited. Here we show that colonic lamina propria (LpM) and muscularis macrophages (MM) consist of monocyte-like cells that differentiate into multiple transcriptionally distinct subsets. LpM comprise subsets with proinflammatory properties and subsets high antigen presenting and phagocytic capacity. The latter are strategically positioned close to the surface epithelium. Most MM differentiate along two trajectories; one that upregulates genes associated with immune activation and angiogenesis, whereas the other upregulates genes associated with neuronal homeostasis. Importantly, MM are located adjacent to neurons and vessels. Cell-cell interaction and gene network analysis indicated that survival, migration, transcriptional reprogramming, and niche-specific localization of LpM and MM are controlled by an extensive interaction with tissue-resident cells and a few key transcription factors.
Kinase independent function of PI3Kγ modulates calcium re-uptake by regulating phospholamban function
Authors: Mohan Maradumane L. , Witherow Connner P. , Papay Robert S. , Sun Yu , Stenson Kate , Prasad Sathyamangla V. Naga 
Published: May 2021

AbstractRationaleGenetic deletion of Phosphoinositide 3-kinase (PI3Kγ) in mice (PI3Kγ−/−) results in increased cAMP levels and enhanced ventricular rate/contractility. Whether PI3Kγ plays a role in cardiac contractility by altering intracellular calcium recycling is not known.ObjectiveTo understand the mechanism of PI3Kγ mediated regulation of cardiac contractility.Methods and ResultsCaffeine treatment of adult cardiomyocytes from PI3Kγ−/− mice showed significantly reduced calcium reuptake by sarcoendoplasmic reticulum (SR) indicating that PI3Kγ locally regulates SR function. This resulted in elevated levels of intracellular calcium for prolonged period following caffeine. Our findings show that delayed re-uptake of calcium was caused by changes in phosphorylation of phospholamban (PLN), a major regulator of SR calcium reuptake. PI3Kγ−/− cardiomyocytes show significantly reduced PLN phosphorylation due to increase in PLN-associated protein phosphatase (PP) activity as reflected by decreased demethylated-PP2A. Consistently, the altered calcium regulation in the cardiomyocytes of PI3Kγ−/− can be restored by inhibition of PP by okadaic acid. Unexpectedly, cardiomyocyate-specific overexpression of kinase-dead PI3Kγ PI3Kγinact) in the global PI3Kγ−/− cardiomyocytes normalized caffeine induced calcium reuptake, restored PLN phosphorylation, and decreased PLN-associated PP activity reflected by increased demethylated-PP2A.ConclusionsThese studies bring-to-fore an unrecognized regulation of PLN by PI3Kγ through PP2A with implications in deleterious cardiac remodeling as PI3Kγ is significantly upregulated following cardiac stress.
Engineered type six secretion systems deliver active exogenous effectors and Cre recombinase
Authors: Hersch Steven J. , Lam Linh , Dong Tao G. 
Published: May 2021

AbstractGenetic editing has revolutionized biotechnology but delivery of endonuclease genes as DNA can lead to aberrant integration or overexpression, leading to off-target effects. Here we develop a mechanism to deliver Cre recombinase as a protein by engineering the bacterial type six secretion system (T6SS). Using multiple T6SS fusion proteins, Aeromonas dhakensis or attenuated Vibrio cholerae donor strains, and a gain-of-function cassette for detecting Cre recombination, we demonstrate successful delivery of active Cre directly into recipient cells. Most efficient transfer was achieved using a truncated version of PAAR2 from V. cholerae, resulting in a relatively small (118 amino acid) ‘delivery tag’. We further demonstrate the versatility of this system by delivering an exogenous effector, TseC, enabling V. cholerae to kill Pseudomonas aeruginosa. This implicates that P. aeruginosa is naturally resistant to all native effectors of V. cholerae and that the TseC chaperone protein is not required for its activity. Moreover, it demonstrates that the engineered system can improve T6SS efficacy against specific pathogens, proposing future application in microbiome manipulation or as a next-generation antimicrobial. Inexpensive and easy to produce, this protein delivery system has many potential applications ranging from studying T6SS effectors to genetic editing.ImportanceDelivery of protein-based drugs, antigens, and gene-editing agents has broad applications. The type VI protein secretion system (T6SS) can target both bacteria and eukaryotic cells and deliver proteins of diverse size and function. Here we harness the T6SS to successfully deliver Cre recombinase to genetically edit bacteria without requiring the introduction of exogenous DNA into the recipient cells. This demonstrates a promising advantage over current genetic editing tools that require transformation or conjugation of DNA. The engineered secretion tag can also deliver a heterologous antimicrobial toxin that kills an otherwise unsusceptible pathogen, Pseudomonas aeruginosa. These results demonstrate the potential of T6SS-mediated delivery in areas including genome editing, killing drug-resistant pathogens, and studying toxin functions.
Colicin-mediated transport of DNA through the iron transporter FepA
Authors: Cohen-Khait Ruth , Harmalkar Ameya , Pham Phuong , Webby Melissa N. , Housden Nicholas G. , Elliston Emma , Hopper Jonathan TS. , Mohammed Shabaz , Robinson Carol V. , Gray Jeffrey J. , Kleanthous Colin 
Published: May 2021

ABSTRACTColicins are protein antibiotics used by bacteria to eliminate competing Escherichia coli. Colicins frequently exploit outer membrane (OM) nutrient transporters to penetrate through the strictly impermeable bacterial cellular envelope. Here, applying live-cell fluorescence imaging we were able to follow colicin B (ColB) into E. coli and localize it within the periplasm. We further demonstrate that single-stranded DNA coupled to ColB is also transported into the periplasm, emphasizing that the import routes of colicins can be exploited to carry large cargo molecules into bacteria. Moreover, we characterize the molecular mechanism of ColB association with its OM receptor FepA, applying a combination of photo-activated crosslinking, mass spectrometry, and structural modeling. We demonstrate that complex formation is coincident with a large-scale conformational change in the colicin. Finally In vivo crosslinking experiments and supplementary simulations of the translocation process indicate that part of the colicin engages active transport by disguising itself to part of the cellular receptor.
Temporal fine structure influences voicing confusions for consonant identification in multi-talker babble
Authors: Viswanathan Vibha , Shinn-Cunningham Barbara G. , Heinz Michael G. 
Published: May 2021

AbstractTo understand the mechanisms of speech perception in everyday listening environments, it is important to elucidate the relative contributions of different acoustic cues in transmitting phonetic content. Previous studies suggest that the envelope of speech in different frequency bands conveys most speech content, while the temporal fine structure (TFS) can aid in segregating target speech from background noise. However, the role of TFS in conveying phonetic content beyond what envelopes convey for intact speech in complex acoustic scenes is poorly understood. The present study addressed this question using online psychophysical experiments to measure the identification of consonants in multi-talker babble for intelligibility-matched intact and 64-channel envelope-vocoded stimuli. Consonant confusion patterns revealed that listeners had a greater tendency in the vocoded (versus intact) condition to be biased toward reporting that they heard an unvoiced consonant, despite envelope and place cues being largely preserved. This result was replicated when babble instances were varied across independent experiments, suggesting that TFS conveys voicing information beyond what is conveyed by envelopes for intact speech in babble. Given that multi-talker babble is a masker that is ubiquitous in everyday environments, this finding has implications for the design of assistive listening devices such as cochlear implants.
Beat Perception in Polyrhythms: Time is Structured in Binary Units
Authors: Møller Cecilie , Stupacher Jan , Celma-Miralles Alexandre , Vuust Peter 
Published: May 2021

AbstractIn everyday life, we group and subdivide time to understand the sensory environment surrounding us. Our perceptual system establishes hierarchical structures by nesting different groups of time intervals. Organizing time in units such as diurnal rhythms, phrases, and beat patterns, is fundamental to everyday behavior, speech, and music. When listening to music, we extract rhythmic regularities to create a hierarchical metrical structure that enables us to predict the timing of the next events. Foot tapping and head bobbing to musical rhythms are observable evidence of this process. In the special case of polyrhythms, at least two metrical structures compete to become the reference for these temporal regularities, rendering several possible beats with which we can synchronize our movements. While there is general agreement that tempo, pitch, and loudness influence beat perception in polyrhythms, we focused on the yet neglected influence of beat subdivisions. In three online experiments, 300 participants listened to a range of polyrhythms and tapped their index fingers in time with the perceived beat. The polyrhythms consisted of two simultaneously presented isochronous pulse trains with different ratios (2:3, 2:5, 3:4, 3:5, 4:5, 5:6) and different tempi. For ratios 2:3 and 3:4, we additionally manipulated the pitch of the pulse trains. Results showed a highly robust influence of subdivision grouping on beat perception manifested as a propensity towards beats that are subdivided into two or four equally spaced units, as opposed to beats with three or more complex groupings of subdivisions. Additionally, lower pitched pulse trains were more likely to be perceived as the beat. Our findings suggest that subdivisions, not beats, are the basic unit of beat perception, and that the principle underlying the binary grouping of subdivisions reflects a propensity towards simplicity. This preference for simple grouping is widely applicable to human perception and cognition of time.
Human-robot skills transfer interface for UAV-based precision pesticide in dynamic environments
Authors: Zhou Xuanyi , He Jilin , Chen Dingping , Li Junsong , Jiang Chunshan , Ji Mengyuan , He Miaolei 
Published: May 2021

Purpose
Nowadays, the global agricultural system is highly dependent on the widespread use of synthetic pesticides to control diseases, weeds and insects. The unmanned aerial vehicle (UAV) is deployed as a major part of integrated pest management in a precision agriculture system for accurately and cost-effectively distributing pesticides to resist crop diseases and insect pests.

Design/methodology/approach
With multimodal sensor fusion applying adaptive cubature Kalman filter, the position and velocity are enhanced for the correction and accuracy. A dynamic movement primitive is combined with the Gaussian mixture model to obtain numerous trajectories through the teaching of a demonstration. Further, to enhance the trajectory tracking accuracy under an uncertain environment of the spraying, a novel model reference adaptive sliding mode control approach is proposed for motion control.

Findings
Experimental studies have been carried out to test the ability of the proposed interface for the pesticides in the crop fields. The effectiveness of the proposed interface has been demonstrated by the experimental results.

Originality/value
To solve the path planning problem of a complex unstructured environment, a human-robot skills transfer interface is introduced for the UAV that is instructed to follow a trajectory demonstrated by a human teacher.
Optimal grasp force for robotic grasping and in-hand manipulation with impedance control
Authors: Li Xiaoqing , Chen Ziyu , Ma Chao 
Published: May 2021

Purpose
The purpose of this paper is to achieve stable grasping and dexterous in-hand manipulation, the control of the multi-fingered robotic hand is a difficult problem as the hand has many degrees of freedom with various grasp configurations.

Design/methodology/approach
To achieve this goal, a novel object-level impedance control framework with optimized grasp force and grasp quality is proposed for multi-fingered robotic hand grasping and in-hand manipulation. The minimal grasp force optimization aims to achieve stable grasping satisfying friction cone constraint while keeping appropriate contact forces without damage to the object. With the optimized grasp quality function, optimal grasp quality can be obtained by dynamically sliding on the object from initial grasp configuration to final grasp configuration. By the proposed controller, the in-hand manipulation of the grasped object can be achieved with compliance to the environment force. The control performance of the closed-loop robotic system is guaranteed by appropriately choosing the design parameters as proved by a Lyapunove function.

Findings
Simulations are conducted to validate the efficiency and performance of the proposed controller with a three-fingered robotic hand.

Originality/value
This paper presents a method for robotic optimal grasping and in-hand manipulation with a compliant controller. It may inspire other related researchers and has great potential for practical usage in a widespread of robot applications.
Which intermediate import source is best for innovation in MNEs?
Authors: Ramírez-Alesón Marisa , Fernández-Olmos Marta 
Published: May 2021

PurposeThis paper explores the importance of the importing intensity for different intermediate inputs depending on their source (internal sourcing or intra-firm trade versus external sourcing or foreign suppliers) for different types of innovation (product and process innovation) and applied to MNEs (foreign versus domestic).Design/methodology/approachThe sample contains 2,448 firm-year observations (2006–2016) of firms located in Spain that belong to an MNE group. The authors applied a conditional mixed process to a panel recursive bivariate probit model with robust standard errors.Findings The authors obtained three key results. First, intermediate imports do not always contribute to improving innovation, since their effects vary depending on their source. Second, intermediate imports from foreign suppliers (external source) are more advantageous for product innovation than those from intra-firm trade (internal source). Third, intermediate imports from intra-firm trade are more important for process innovation than those from foreign suppliers. Thus, the impact of importing intermediate inputs on innovation is contingent on the source of the imports, the ownership of the MNE and the type of innovation.Originality/valueThe paper contributes to this topic with new insights and results for MNEs. It identifies which import source is best for innovation depending on the type of innovative result expected. Moreover, it helps to uncover simultaneity and causal relationships between product and process innovation, issues which have not previously been considered in the literature.
It is not a case of “one size fits all”: the need for customized HRM practices for employee engagement
Authors: Jose Geetha , M. Nimmi P. , Mampilly Sebastian Rupert 
Published: May 2021

Purpose
This study seeks to evaluate the role of HRM practices in enhancing Employee Engagement, particularly at varying levels of perceived psychological safety.

Design/Methodology/Approach
Data collected through a questionnaire survey of 151 nurses are analyzed with warp-PLS structural equation modeling.

Findings
Perceived HRM practices lead to higher engagement levels. Psychological safety moderates the relationship between HRM practices and employee engagement inversely.

Originality/value
An un-preceded study examining the moderating role of Psychological safety on the instrumentality of HRM practices on engagement particularly among experienced medical care providers. Results suggest to provide customized HRM practices to experienced nurses in order to enhance their engagement levels.
On the forced convective flow inside thermal collectors enhanced by porous media: from macro to micro-channels
Authors: Dehghan Maziar , Azari Nesaz Zahra , Pourrajabian Abolfazl , Rashidi Saman 
Published: May 2021

Purpose
Aiming at finding the velocity distribution profile and other flow characteristic parameters such as the Poiseuille (Po) number, this study aims to focus on the three-dimensional forced convective flow inside rectangular ducts filled with porous media commonly used in air-based solar thermal collectors to enhance the thermal performance. The most general model for the fluid flow (i.e. the non-linear Darcy–Brinkman–Forchheimer partial differential equation subjected to slip and no-slip boundary conditions) is considered.

Design/methodology/approach
The general governing equations are solved analytically based on the perturbation technique and the results are validated against numerical simulation study based on a finite-difference solution over a non-uniform but structured grid.

Findings
The analytical velocity distribution profile based on exponential functions for the above-mentioned general case is obtained, and accordingly, expressions for the Po are introduced. It is found that the velocity distribution tends to be uniform by increasing the aspect ratio of the duct. Moreover, a criterion for considering/neglecting the nonlinear drag term in the momentum equation (i.e. the Forchheimer term) is proposed. According to the sensitivity analysis, results show that the nonlinear drag term effects on the Nusselt number are important only in porous media with high Darcy numbers.

Originality/value
A general analytic solution for three-dimensional forced convection flows through rectangular ducts filled with porous media for the general model of Darcy–Brinkman–Forchheimer and the general boundary condition including both no-slip and slip-flow regimes is obtained. An analytic expression to calculate Po number is obtained which can be practical for engineering estimations and a basis for validation of numerical simulations. A criterion for considering/neglecting the nonlinear drag term in the momentum equation is also introduced.
COVID-19 and overconfidence bias: the case of developed, emerging and frontier markets
Authors: Shrotryia Vijay Kumar , Kalra Himanshi 
Published: May 2021

PurposeThe main purpose of the present study is to delve into the overconfidence bias in global stock markets during both pre COVID-19 and COVID-19 phases.Design/methodology/approachThe present study makes use of daily adjusted closing prices and volume of the broad market indices of 46 global stock markets over a period ranging from July 2015 till June 2020. The sample period is split into pre COVID-19 and COVID-19 phases. In order to test the overconfidence fallacy in the chosen stock markets, bivariate market-wide vector auto regression (VAR) models and impulse response functions (IRFs) have been employed in both phases.FindingsA highly significant contemporaneous relationship between market return and volume appears to be more pronounced in the Japanese, US, Chinese and Vietnamese stock markets in the pre COVID-19 era for the relevant coefficients are positive and highly significant for most lags. Coming to the period of turbulence, the present study discovers strong overconfident behavior in the Chinese, Taiwanese, Turkish, Jordanian and Vietnamese stock markets during COVID-19 phase.Practical implicationsA stark finding is that none of the developed stock markets reveal strong overconfidence bias during pandemic, suggesting a loss or decline in the investors' confidence. Therefore, the regulators should try to regain the investors' trust and confidence in the markets by ensuring honest, fair and transparent practices. The money managers should reduce the transaction cost to encourage trading and educate investors to hold a well-diversified portfolio to mitigate risk in the long run. The governments may launch recovery packages focusing on sustaining and improving economic activities. Finally, a better investment culture may be built by the corporate houses through good corporate governance practices to regain lost trust.Originality/valueThe present study appears to be the very first attempt to gauge overconfidence bias in the wake of a recent COVID-19 pandemic.
Catastrophic supply chain disruptions and supply network changes: a study of the 2011 Japanese earthquake
Authors: Son Byung-Gak , Chae Sangho , Kocabasoglu-Hillmer Canan 
Published: May 2021

PurposeCatastrophic supply chain disruptions can significantly damage the operational and financial performance of firms. While a growing body of literature on supply network structures has studied what influences supply networks' vulnerability to supply chain disruptions and capability to recover from them, it remains unclear how supply network structures change after major supply chain disruptions. We aim to provide an understanding of how these changes occur.Design/methodology/approachUsing a natural experiment approach and supply network data from Factset, this study investigates how firms' supply network structures change after experiencing the catastrophic supply chain disruptions caused by the 2011 Tohoku earthquake and tsunami in Japan. We capture post-earthquake supply network changes using the measures of degree centrality and ego network density.FindingsThe results of the analysis suggest that compared to unaffected firms, the affected firms experience changes in their supply network structures tending toward lower complexity measured by in-degree centrality, out-degree centrality and ego network density.Originality/valueThis study contributes to social network theory and the complex adaptive supply network literature by providing empirical evidence of structural changes in supply networks after catastrophic supply chain disruptions. A managerial contribution is made by providing a reflection on why these changes might be occurring and alert firms to the challenges of managing complexity in their supply networks.