bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzyme catalysis prior to aromatic residues: Reverse engineering of a dephospho‐CoA kinase
Authors: Makarov Mikhail , Meng Jingwei , Tretyachenko Vyacheslav , Srb Pavel , Březinová Anna , Giacobelli Valerio Guido , Bednárová Lucie , Vondrášek Jiří , Dunker A. Keith , Hlouchová Klára 
Published: March 2021

AbstractThe wide variety of protein structures and functions results from the diverse properties of the 20 canonical amino acids. The generally accepted hypothesis is that early protein evolution was associated with enrichment of a primordial alphabet, thereby enabling increased protein catalytic efficiencies and functional diversification. Aromatic amino acids were likely among the last additions to genetic code. The main objective of this study was to test whether enzyme catalysis can occur without the aromatic residues (aromatics) by studying the structure and function of dephospho‐CoA kinase (DPCK) following aromatic residue depletion. We designed two variants of a putative DPCK from Aquifex aeolicus by substituting (a) Tyr, Phe and Trp or (b) all aromatics (including His). Their structural characterization indicates that substituting the aromatics does not markedly alter their secondary structures but does significantly loosen their side chain packing and increase their sizes. Both variants still possess ATPase activity, although with 150–300 times lower efficiency in comparison with the wild‐type phosphotransferase activity. The transfer of the phosphate group to the dephospho‐CoA substrate becomes heavily uncoupled and only the His‐containing variant is still able to perform the phosphotransferase reaction. These data support the hypothesis that proteins in the early stages of life could support catalytic activities, albeit with low efficiencies. An observed significant contraction upon ligand binding is likely important for appropriate organization of the active site. Formation of firm hydrophobic cores, which enable the assembly of stably structured active sites, is suggested to provide a selective advantage for adding the aromatic residues.
Life‐cycle reliability‐based robust design optimization for GP model with response uncertainty
Authors: Feng Zebiao , Wang Jianjun , Ma Yizhong , Yang Guikang 
Published: March 2021

AbstractReliability‐based robust design optimization (RBRDO) is a crucial tool for life‐cycle quality improvement. Gaussian process (GP) model is an effective alternative modeling technique that is widely used in robust parameter design. However, there are few studies to deal with reliability‐based design problems by using GP model. This article proposes a novel life‐cycle RBRDO approach concerning response uncertainty under the framework of GP modeling technique. First, the hyperparameters of GP model are estimated by using the Gibbs sampling procedure. Second, the expected partial derivative expression is derived based on GP modeling technique. Moreover, a novel failure risk cost function is constructed to assess the life‐cycle reliability. Then, the quality loss function and confidence interval are constructed by simulated outputs to evaluate the robustness of optimal settings and response uncertainty, respectively. Finally, an optimization model integrating failure risk cost function, quality loss function, and confidence interval analysis approach is constructed to find reasonable optimal input settings. Two case studies are given to illustrate the performance of the proposed approach. The results show that the proposed approach can make better trade‐offs between the quality characteristics and reliability requirements by considering response uncertainty.
The MADMAX data set for visual‐inertial rover navigation on Mars
Authors: Meyer Lukas , Smíšek Michal , Fontan Villacampa Alejandro , Oliva Maza Laura , Medina Daniel , Schuster Martin J. , Steidle Florian , Vayugundla Mallikarjuna , Müller Marcus G. , Rebele Bernhard , Wedler Armin , Triebel Rudolph 
Published: March 2021

AbstractPlanetary rovers increasingly rely on vision‐based components for autonomous navigation and mapping. Developing and testing these components requires representative optical conditions, which can be achieved by either field testing at planetary analog sites on Earth or using prerecorded data sets from such locations. However, the availability of representative data is scarce and field testing in planetary analog sites requires a substantial financial investment and logistical overhead, and it entails the risk of damaging complex robotic systems. To address these issues, we use our compact human‐portable DLR Sensor Unit for Planetary Exploration Rovers (SUPER) in the Moroccan desert to show resource‐efficient field testing and make the resulting Morocco‐Acquired data set of Mars‐Analog eXploration (MADMAX) publicly accessible. The data set consists of 36 different navigation experiments, captured at eight Mars analog sites of widely varying environmental conditions. Its longest trajectory covers 1.5 km and the combined trajectory length is 9.2 km. The data set contains time‐stamped recordings from monochrome stereo cameras, a color camera, omnidirectional cameras in stereo configuration, and from an inertial measurement unit. Additionally, we provide the ground truth in position and orientation together with the associated uncertainties, obtained by a real‐time kinematic‐based algorithm that fuses the global navigation satellite system data of two body antennas. Finally, we run two state‐of‐the‐art navigation algorithms, ORB‐SLAM2 and VINS‐mono, on our data to evaluate their accuracy and to provide a baseline, which can be used as a performance reference of accuracy and robustness for other navigation algorithms. The data set can be accessed at https://rmc.dlr.de/morocco2018.
Quantifying Acceptable Artefact Ranges for Dermatologic Classification Algorithms
Authors: Petrie T.C. , Larson C. , Heath M. , Samatham R. , Davis A. , Berry E.G. , Leachman S.A. 
Published: March 2021

Abstract

Background
Many classifiers have been developed that can distinguish different types of skin lesions (e.g., benign nevi, melanoma) with varying degrees of success.1–5 However, even successfully trained classifiers may perform poorly on images that include artefacts. While problems created by hair and ink markings have been published, quantitative measurements of blur, colour and lighting variations on classification accuracy has not yet been reported to our knowledge.

Objectives
We created a system that measures the impact of various artefacts on machine learning accuracy. Our objectives were to (1) quantitatively identify the most egregious artefacts and (2) demonstrate how to assess a classification algorithm's accuracy when input images include artefacts.

Methods
We injected artefacts into dermatologic images using techniques that could be controlled with a single variable. This allows us to quantitatively evaluate the impact on the accuracy. We trained two convolutional neural networks on two different binary classification tasks and measured the impact on dermoscopy images over a range of parameter values. The area under the curve and specificity-at-a-given-sensitivity values were measured for each artefact induced at each parameter.

Results
General blur had the strongest negative effect on the melanoma versus other task. Conversely, shifting the hue towards blue had a more pronounced effect on the suspicious versus follow task.

Conclusions
Classifiers should either mitigate artefacts or detect them. Images should be excluded from diagnosis/recommendation when artefacts are present in amounts outside the machine perceived quality range. Failure to do so will reduce accuracy and impede approval from regulatory agencies.
Longitudinal transitions in patterns of post‐traumatic stress disorder symptoms and psychological distress among South Korean adults with traumatic experiences
Authors: Jung Hayoung , Lee DongHun , Lee Deokhee 
Published: March 2021

AbstractThis study aimed to investigate transitions in patterns of post‐traumatic stress disorder (PTSD) symptoms and psychological distress among South Koreans with traumatic experiences. This study consists of two parts: In Part 1 the time since trauma ranged between 0 and 41 years, while in Part 2 participants experienced at least one traumatic event within the previous three years. We identified subgroups and transitions between classes over a one‐year period using latent profile analysis and latent transition analysis. First, in Part 1, four classes were identified at T1 and T2. Second, we explored whether age, sex, time since trauma, and time perspective (TP) predicted class membership at T1. Age, past‐negative (PN), present‐fatalistic, and future TPs were significant predictors of class membership at T1. Finally, sex, PN, and future TPs were identified as significant predictors of class transition over time. The same analysis was conducted in Part 2 with individuals chosen from the Part 1 participants. Differential effects of TP on class membership and transitions in PTSD symptoms and psychological distress indicated the need for intervention programs that consider the TP profiles of individuals with traumatic experiences.
Zeolite‐Based Memristive Synapse with Ultralow Sub‐10‐fJ Energy Consumption for Neuromorphic Computation
Authors: Zeng Tao , Zou Xiaoqin , Wang Zhongqiang , Yu Guangli , Yang Zhi , Rong Huazhen , Zhang Chi , Xu Haiyang , Lin Ya , Zhao Xiaoning , Ma Jiangang , Zhu Guangshan , Liu Yichun 
Published: March 2021

AbstractThe development of neuromorphic computation faces the appreciable challenge of implementing hardware with energy consumption on the level of a femtojoule per synaptic event to be comparable with the energy consumption of human brain. Controllable ultrathin conductive filaments are needed to achieve such extremely low energy consumption in memristive synapses but their formation is difficult to control owing to their stochastic morphology and unexpected overgrowth. Herein, a zeolite‐based memristive synapse is demonstrated for the first time, in which Ag exchange in the sub‐nanometer pore closely resembles synaptic Ca2+ dynamics across biomembrane channel. Particularly, the confined ultrasmall pore and low Ag ion migration barrier give the zeolite‐based memristive synapse ultralow energy consumption below 10 fJ per synaptic spike, on par with the biological counterpart. Experimental results reveal that the gradual memristive effect is attributed to the dimension modulation of Ag clusters. In addition to emulating inherent cognitive functions through electrical stimulations, the experience‐dependent transition of short‐term plasticity to long‐term plasticity using a chemical modulation method is achieved by treating the initial Ag quantity as a learning experience. The proposed memristors can be used to develop highly efficient memristive neural networks and are considered as a candidate for application in neuromorphic computation.
Electrochemical Capacitor Performance of Nanotextured Carbon/Transition Metal Dichalcogenides Composites
Authors: Frąckowiak Elżbieta , Foroutan Koudahi Masoud , Tobis Maciej 
Published: March 2021

AbstractTransition metal dichalcogenides (TMDs) are emerging low‐dimensional materials with potential applications for electrochemical capacitors (EC). Here, physicochemical and electrochemical characterizations of carbon composites with two sulfides ReS2 and FeS2 are reported. To enhance conductivity, multiwalled carbon nanotubes (NTs) serve as a support for ReS2 while 3D graphene‐like network (3DG) is utilized for FeS2 deposition. Unique structure of carbon/TMDs composites allows a faradaic contribution of sulfides to be exploited. Capacitance values, charge/discharge efficiency, capacitance retention, charge propagation, cyclabilty, and voltage limits of EC with carbon/sulfide composites in aqueous neutral solutions (Li2SO4, Na2SO4) are analyzed. Special attention is devoted to energetic efficiency of capacitive charge/discharge processes. Structure‐to‐capacitance correlation for the composites with various TMDs loading is thoroughly emphasized. The more defected structure of layered NTs/ReS2 composite is responsible for the lower capacitor voltage (0.8 V) owing to quicker electrolyte decomposition. Additionally, the catalytic effect of Re for hydrogen evolution reaction plays a crucial role in EC voltage restriction. Contrary, the operating voltage of capacitor based on 3DG/FeS2 is able to be extended until 1.5 V in sodium sulfate electrolytic solution.
Few‐Layer Tellurium: Cathodic Exfoliation and Doping for Collaborative Hydrogen Evolution
Authors: Zheng Weiran , Li Yong , Liu Mengjie , Lee Lawrence Yoon Suk 
Published: March 2021

Abstract2D tellurium is a suitable electrocatalyst support that can assist electron transport while hosting active sites, yet its production remains challenging. Herein, a cathodic exfoliation method that can exfoliate Te crystal directly to Te nanosheets at low potential, also enabling simultaneous transition metal doping on Te nanosheet surface is presented. In situ Raman spectra and ex situ characterizations reveal that the cathodic exfoliation relies on the electrostatic repulsion between Te flakes covered with in situ generated ditelluride (Te22−) anions. The Te22− anions can anchor metal ions to the surface, and the doping concentration can be tuned by adjusting the concentration of metal ion in the electrolyte. The metal‐doped Te nanosheets exhibit highly improved hydrogen evolution activities. In particular, Pt‐doped Te outperforms polycrystalline Pt at high overpotential. A collaborative hydrogen production mechanism via Volmer–Heyrovsky pathway is suggested: Te22− adsorbs protons and assists the mass transfer to adjacent Pt atoms where the protons are reduced and released as hydrogen.
Surfactant‐in‐Polymer Templating for Fabrication of Carbon Nanofibers with Controlled Interior Substructures: Designing Versatile Materials for Energy Applications
Authors: Heo Eunseo , Noh Seonmyeong , Lee Unhan , Le Thanh‐Hai , Lee Haney , Jo Hyemi , Lee Sanghyuck , Yoon Hyeonseok 
Published: March 2021

AbstractA simple, scalable, surfactant‐in‐polymer templating approach is demonstrated to create controlled long‐range secondary substructures in a primary structure. A metal bis(2‐ethylhexyl) sulfosuccinate (MAOT) as the surfactant is shown to be capable of serving as a sacrificial template and metal precursor in carbon nanofibers. The low interfacial tension and controllable dimensions of the MAOT are maintained in the solid‐phase polymer, even during electrospinning and heat‐treatment processes, allowing for the long‐range uniform formation of substructures in the nanofibers. The MAOT content is found to be a critical parameter for tailoring the diameter of the nanofibers and their textural properties, such as size and volume of interior pores. The metal counterion species in the MAOT determine the introduction of metallic phases in the nanofiber interior. The incorporation of MAOT with Na as the counterion into the polymer phase leads to the formation of a built‐in pore structure in the nanofibers. In contrast, MAOT with Fe as a counterion generates unique iron‐in‐pore substructures in the nanofibers (FeCNFs). The FeCNFs exhibit outstanding charge storage and water splitting performances. As a result, the MAOT‐in‐polymer templating approach can be extended to combinations of various metal precursors and thus create desirable functionalities for different target applications.
An Experimentally Verified LC‐MS Protocol toward an Economical, Reliable, and Quantitative Isotopic Analysis in Nitrogen Reduction Reactions
Authors: Saji Sandra Elizabeth , Lu Haijiao , Lu Ziyang , Carroll Adam , Yin Zongyou 
Published: March 2021

AbstractTo substitute the energy‐intensive Haber‐Bosch process for the synthesis of ammonia, some labile techniques, such as photocatalysis, electrocatalysis, photoelectrocatalysis, and photothermocatalysis, have emerged and attracted intense research interest. However, the contamination of the reaction system is one of the major concerns on how to reliably and accurately evaluate the performance of these catalysts, which is why various control studies are involved. Isotopic labeling studies are one of the most reliable control strategies in nitrogen fixation experiments, to ensure that N2 is exclusively the source of the generated ammonia. As a convenient, sensitive and accurate technique distinguished with a quantitative atomic mass resolution, liquid chromatography‐mass spectrometry (LC‐MS) has been extensively employed for the detection of ammonia in aqueous electrolyte systems. However, the previous work protocols for 15N2 isotopic analysis using LC‐MS either involved hazardous procedures which could potentially damage the instrument, or lacked in their experimental verification using real samples. Herein, a safe, reproducible and economical protocol for the detection of ammonia using LC‐MS is presented, exhibiting an exponentially steep progressive detectivity of 15N abundance, well verified with a series of experimental results for nitrogen reduction reactions. This is expected to provide a prudent cost‐effective and sustainable gateway into isotopic analysis.
A lightweight virtualization model to enable edge computing in deeply embedded systems
Authors: Tiburski Ramão T. , Moratelli Carlos R. , Johann Sérgio F. , de Matos Everton , Hessel Fabiano 
Published: March 2021

AbstractEdge computing paradigm enables moving Internet of Things (IoT) applications from the Cloud to the edge of the network. Modern software engineering approaches are adhering to microservices to enable the deployment of such applications on edge devices. Microservices consist of the disaggregation of an application into smaller pieces that operate independently. Recent works have explored microservices packaged into containers and advocate that containers result in a reduced footprint and avoid the unwanted overhead caused by traditional virtualization. However, containers cannot be used in many deeply embedded systems (DES) due to an underlying operating system's (OSs) requirement. DES are edge devices with minimal resources regarding storage, memory, and processing power. Thus, they cannot afford large and sophisticated OSs. This article presents the Hellfire hypervisor, a lightweight virtualization implementation that enables separation and improves security in IoT applications on DES. Our proposal simplifies the traditional hypervisor approach and reaches devices where the existing techniques fail. The results show that the proposed model has a small footprint of 23 KB while keeping a low average virtualization overhead of 0.62% for multiple virtual machines execution.
Public–private entrepreneurial financing partnership model in Nigeria
Authors: Ochinanwata Nonso , Ezepue Patrick Oseloka , Nwankwo Theodore Chinonso , Ochinanwata Chinedu , Igwe Paul Agu 
Published: March 2021

AbstractThis article critically examines some of the financing sources available to small and medium‐sized enterprises (SMEs) and factors that influence investor's decisions. Based on a qualitative approach, this study draws on evidence from Nigerian digital firms, public, and private financers to explore suitable entrepreneurial financing model for SMEs. Thus, it extends the understanding of combinations of entrepreneurial finance and funding in the African context. The study offers fresh and rare illustrative insights on how public–private entrepreneurial finance partnership will provide affordable and adequate access to entrepreneurial finance. It further highlights the impact and relevance of different entrepreneurial financiers on SMEs development and growth. It recommends a collaborative partnership initiative that involves public and private financial consultants and business incubators working together to ensure that SMEs have access to appropriate finance for growth, development, and business sustainability.
Rigid polyurethane foams reinforced with ultrafine powder from automotive shredder residue
Authors: Song Kaixuan , Li Yijun , Nie Min , Wang Qi 
Published: March 2021

AbstractWith the booming of the abandoned cars, automobile shredding residual (ASR) increase sharply in recent years. ASRs contain complex components that are difficult to separate and recycle, causing serious environmental impacts. Herein, we report a new strategy for ASR recycling to prepare high value‐added rigid polyurethane foams (RPUFs) with excellent mechanical and thermal properties. Ultrafine ASR powder with homogeneous domain size and activated functional groups, added to the precursor of RPUFs as reinforcing fillers, was fabricated through solid‐state shear milling (S3M) technology. As a nucleating agent, ASR particles can participate in the foaming procedure of RPUFs, which decreased the cell size to ~0.2 mm. Owing to the strong interaction between the ASR and polyurethane matrix, the thermal degradation temperature increased to 246.7°C, 42.4°C higher than the neat one. Inspiringly, the ASR particles can act as reinforcing elements in the cell walls, which can not only increase the compressive strength and modulus to 1.79 and 0.1 MPa respectively, 81% and 71% higher than the neat sample, but also enhance the long‐term fatigue resistance of the foam. This strategy achieves the recycling and utilization of ASR, and expands the application scope of RPUFs as well.
Doing Dirty Work: Listening for Ignorance Among the Ruins of Reflexivity in Music Education Research
Authors: Kallio Alexis Anja 
Published: March 2021

AbstractRecent research in music education has emphasized the importance of reflexive approaches in unsettling the concept of a neutral, objective researcher and critically considered the ways in which cultural others are represented in research texts. Seen to enhance both the rigor and ethical dimensions of research practice, reflexivity has emerged as a hegemonic virtue, highlighting the inherently political aspects of research practice. In this chapter, I interrogate the politics of inquiry involved in reflexive research, considering the ways in which reflexivity may afford the researcher methodological power and hinder relational and responsible work. Reflexivity is thus positioned as a ruin: perpetually reaffirming the benevolence of the already-privileged researcher while doing little to disrupt the structures that keep such privileges at the center of academic practice. However, rather than abandoning such practices altogether, I suggest that reflexivity might be better considered as a way to listen for ignorance and direct attention toward ontological or epistemological difference. In this way, reflexivity serves as an invitation to engage in the politics of diversity through the transformation of researchers themselves.
MOVING: A User-Centric Platform for Online Literacy Training and Learning
Authors: Apaolaza Aitor , Backes Tobias , Barthold Sabine , Bienia Irina , Blume Till , Collyda Chrysa , Fessl Angela , Gottfried Sebastian , Grunewald Paul , Günther Franziska , Köhler Thomas , Lorenz Robert , Heinz Matthias , Herbst Sabrina , Mezaris Vasileios , Nishioka Chifumi , Pournaras Alexandros , Sabol Vedran , Saleh Ahmed , Scherp Ansgar , Simic Ilija , Skulimowski Andrzej M.J. , Vagliano Iacopo , Vigo Markel , Wiese Michael , Zdolšek Draksler Tanja 
Published: March 2021

AbstractIn this paper, we present an overview of the MOVING platform, a user-driven approach that enables young researchers, decision makers, and public administrators to use machine learning and data mining tools to search, organize, and manage large-scale information sources on the web such as scientific publications, videos of research talks, and social media. In order to provide a concise overview of the platform, we focus on its front end, which is the MOVING web application. By presenting the main components of the web application, we illustrate what functionalities and capabilities the platform offer its end-users, rather than delving into the data analysis and machine learning technologies that make these functionalities possible.