bluuebunny/crossref_metadata_2025 huggingface dataset:
Racial Influences on Pediatric Tracheostomy Outcomes
Authors: Johnson Romaine F. , Brown Clarice M. , Beams Dylan R. , Wang Cynthia S. , Shah Gopi B. , Mitchell Ron B. , Chorney Stephen R.
Published: September 2021

Objectives/Hypothesis

To determine the impact of race on outcomes after pediatric tracheostomy.

Study Design

Retrospective case series.

Methods

A case series of tracheostomies at an urban, tertiary care children's hospital between 2014 and 2019 was conducted. Children were grouped by race to compare neurocognition, mortality, and decannulation rate.

Results

A total of 445 children with a median age at tracheostomy of 0.46 (interquartile range [IQR]: 0.97) years were studied. The cohort was 32% Hispanic, 31% White, 30% Black, 2.9% Asian, and 4.3% other race. Black compared to White children had a lower median birth weight (2,022 vs. 2,449 g, P = .005), were more often extremely premature (≤28 weeks gestation: 62% vs. 57%, P = .007), and more frequently had bronchopulmonary dysplasia (BPD) (35% vs. 17%, P = .002). Hispanic compared to Black children had higher median birth weight (2,529 g, P < .001), less extreme prematurity (44%, P < .001), and less BPD (21%, P = .04). The proportion of Black children was higher (30% vs. 19%, P < .001), while the proportion of Hispanic children with a tracheostomy was lower (32% vs. 42%, P = .003) compared to the racial distribution of all pediatric admissions. Racial differences were not seen for rates of severe neurocognitive disability (P = .51), decannulation (P = .17), or death (P = .92) after controlling for age, sex, prematurity, and ventilator dependence.

Conclusion

Black children disproportionately underwent tracheostomy and had a higher comorbidity burden than White or Hispanic children. Hispanic children had proportionally fewer tracheostomies. Neurocognitive ability, decannulation, and mortality were similar for all races implying that health disparities by race may not change long‐term outcomes after pediatric tracheostomy. Laryngoscope, 132:1118–1124, 2022
An Isolated Dose of Extra‐Virgin Olive Oil Produces a Better Postprandial Gut Hormone Response, Lipidic, and Anti‐Inflammatory Profile that Sunflower Oil: Effect of Morbid Obesity
Authors: Garcia‐Serrano Sara , Ho‐Plagaro Ailec , Santiago‐Fernandez Concepción , Rodríguez‐Díaz Cristina , Martín‐Reyes Flores , Valdes Sergio , Moreno‐Ruiz Francisco J. , Lopez‐Gómez Carlos , García‐Fuentes Eduardo , Rodríguez‐Pacheco Francisca
Published: September 2021

Introduction

This study evaluates the effects of 25 mL of three types of oils [extra‐virgin olive oil (EVOO), olive oil (OO), and sunflower oil (SO)] on postprandial (3 h) satiety markers and variables related to metabolic status and inflammation in non‐obese patients (n= 6) and in those with morbid obesity (n= 6), before and 1 year after Roux‐en‐Y gastric by‐pass (RYGB).

Methods and Results

After EVOO intake, serum acylated ghrelin decreases and GLP1 increases more than with OO and SO. EVOO causes a higher increase of insulin and lower postprandial hypertriglyceridemia and free fatty acid levels than with OO and SO. EVOO decreases TNFα and IL6 expression in peripheral blood mononuclear cells, with OO inducing intermediate effects and SO inducing an increase of these proinflammatory markers. These results are observed in non‐obese patients and in those with morbid obesity after RYGB. However, patients with morbid obesity before RYGB show a profound alteration of this response.

Conclusion

EVOO produces more beneficial effects than OO, which has lower amounts of minor components, and SO, which has PUFA as its main component. RYGB produces an improvement in the metabolic response to all three types of oils in patients with morbid obesity.
Automated segmentation of biventricular contours in tissue phase mapping using deep learning
Authors: Shen Daming , Pathrose Ashitha , Sarnari Roberto , Blake Allison , Berhane Haben , Baraboo Justin J. , Carr James C. , Markl Michael , Kim Daniel
Published: September 2021

Tissue phase mapping (TPM) is an MRI technique for quantification of regional biventricular myocardial velocities. Despite its potential, clinical use is limited due to the requisite labor‐intensive manual segmentation of cardiac contours for all time frames. The purpose of this study was to develop a deep learning (DL) network for automated segmentation of TPM images, without significant loss in segmentation and myocardial velocity quantification accuracy compared with manual segmentation. We implemented a multi‐channel 3D (three dimensional; 2D + time) dense U‐Net that trained on magnitude and phase images and combined cross‐entropy, Dice, and Hausdorff distance loss terms to improve the segmentation accuracy and suppress unnatural boundaries. The dense U‐Net was trained and tested with 150 multi‐slice, multi‐phase TPM scans (114 scans for training, 36 for testing) from 99 heart transplant patients (44 females, 1‐4 scans/patient), where the magnitude and velocity‐encoded (Vx, Vy, Vz) images were used as input and the corresponding manual segmentation masks were used as reference. The accuracy of DL segmentation was evaluated using quantitative metrics (Dice scores, Hausdorff distance) and linear regression and Bland‐Altman analyses on the resulting peak radial and longitudinal velocities (Vr and Vz). The mean segmentation time was about 2 h per patient for manual and 1.9 ± 0.3 s for DL. Our network produced good accuracy (median Dice = 0.85 for left ventricle (LV), 0.64 for right ventricle (RV), Hausdorff distance = 3.17 pixels) compared with manual segmentation. Peak Vr and Vz measured from manual and DL segmentations were strongly correlated (R ≥ 0.88) and in good agreement with manual analysis (mean difference and limits of agreement for Vz and Vr were −0.05 ± 0.98 cm/s and −0.06 ± 1.18 cm/s for LV, and −0.21 ± 2.33 cm/s and 0.46 ± 4.00 cm/s for RV, respectively). The proposed multi‐channel 3D dense U‐Net was capable of reducing the segmentation time by 3,600‐fold, without significant loss in accuracy in tissue velocity measurements.
Simulating permissionless blockchains: Distribution fitting, tool support, and a case study
Authors: Alharby Maher , van Moorsel Aad
Published: September 2021

Discrete‐event simulation is an important tool for the analysis of permissionless blockchain systems. Simulation allows one to evaluate blockchains for scenarios that cannot be mimicked easily on the life system. To simulate blockchain systems as close to reality as possible a realistic characterization of the probability distributions of various variables is required. In this paper, we obtain frequency distributions for Ethereum smart contract transactions with respect to gas limit, used gas, gas price, and CPU time. The distribution fitting utilizes Gaussian mixture models, correlation analysis, and ensemble regression techniques, and we demonstrate the appropriateness of each of these methods. We use publicly available Ethereum smart contract data, supplemented with experimental data for over 300,000 smart contracts obtained on a test bed. In addition, we extend the BlockSim simulation tool to support the required distributions and use the simulator for a case study in optimizing miner returns through transaction selection strategies in Ethereum under future scenarios. The outcomes not only demonstrate the impact of selection strategies on miner return but also demonstrate the sensitivity of the outcomes to chosen distributions and therefore illustrate the importance of using realistic distributions.
Hierarchical‐matrix method for a class of diffusion‐dominated partial integro‐differential equations
Authors: Gathungu Duncan , Bebendorf Mario , Borzì Alfio
Published: September 2021

A hierarchical matrix approach for solving diffusion‐dominated partial integro‐differential problems is presented. The corresponding diffusion‐dominated differential operator is discretized by a second‐order accurate finite‐volume scheme, while the Fredholm integral term is approximated by the trapezoidal rule. The hierarchical matrix approach is used to approximate the resulting algebraic problem and includes the implementation of an efficient preconditioned generalized minimum residue (GMRes) solver. This approach extends previous work on integral forms of boundary element methods by taking into account inherent characteristics of the diffusion‐dominated differential operator in the resultant algebraic problem. Numerical analysis estimates of the accuracy and stability of the finite‐volume and the trapezoidal rule approximation are presented and combined with estimates of the hierarchical‐matrix approximation and with the accuracy of the GMRes iterates. Results of numerical experiments are reported that successfully validate the theoretical accuracy and convergence estimates, and demonstrate the almost optimal computational complexity of the proposed solution procedure.
Water Contamination Lawsuits Help Water Utilities Pay for Cleanup
Authors: Mortvedt Nancy , Mansergh Seth
Published: September 2021

Defective commercial products near surface and groundwater sources and consumer products that release harmful chemicals into the water system are a real threat to safe drinking water. It's key to have a strategy to hold polluters accountable, and in some cases, litigation may be the best option.
Influence of demographics variables on students subjective well‐being
Authors: Mewafarosh Rekha , Agarwal Shivani
Published: September 2021

The paper is an attempt to investigate the impact of demographic variables on the level of the subjective well‐being (SWB) of students enrolled in premiere business school. SWB was measured through a three‐dimensional approach consisting of life satisfaction, positive affect, and negative affect using Life Scaleand Positive Affect & Negative Affect Scale. Data was collected from 352 students and using OLS regression method, significant differences regarding SWB were examined. Research findings show a significant difference in the exhibition of most of the demographic variables and SWB. This paper presents data and provides insights into the level of SWB of students enrolled in premiere business School.
Investigation of metal‐polymer composites manufactured by fused deposition modeling with regard to process parameters
Authors: Moritzer Elmar , Elsner Christian Lennart , Schumacher Christian
Published: September 2021

A comparatively new approach for the manufacturing of metal parts is the use of fused deposition modeling (FDM). Here, a metal powder filled filament is processed to manufacture components (green part). The subsequent process chain is identical to that of metal injection molding (MIM). Thus, the polymer binder is initially removed from the component (brown part). The metal particles are finally sintered in a furnace to form a pure metal component (white part/final part). The aim of this study is the investigation of the FDM process for the fabrication of metal components with regard to process parameters. This includes the consideration of material‐specific parameters influencing the extrusion process. Especially, the material temperature and material behavior within the FDM nozzle are analyzed. On this basis, the mechanical properties of specimens manufactured with different nozzle sizes and strand geometries are examined. The resulting properties are used to evaluate the suitability of the specific strand‐nozzle combination for processing the metal‐polymer composite. In particular, the density of the components and the process reliability are important evaluation criteria. Finally, the comparison of white parts with parts manufactured in selective laser melting (SLM) shows the possibilities offered by processing metal‐polymer composites in FDM.
A glutamate concentration‐biased allosteric modulator potentiates NMDA‐induced ion influx in neurons
Authors: Costa Blaise M. , Kwapisz Lina Cortés , Mehrkens Brittney , Bledsoe Douglas N. , Vacca Bryanna N. , Johnston Tullia V. , Razzaq Rehan , Manickam Dhanasekaran , Klein Bradley G.
Published: September 2021

Precisely controlled synaptic glutamate concentration is essential for the normal function of the N‐methyl D‐aspartate (NMDA) receptors. Atypical fluctuations in synaptic glutamate homeostasis lead to aberrant NMDA receptor activity that results in the pathogenesis of neurological and psychiatric disorders. Therefore, glutamate concentration‐dependent NMDA receptor modulators would be clinically useful agents with fewer on‐target adverse effects. In the present study, we have characterized a novel compound (CNS4) that potentiates NMDA receptor currents based on glutamate concentration. This compound alters glutamate potency and exhibits no voltage‐dependent effect. Patch‐clamp electrophysiology recordings confirmed agonist concentration‐dependent changes in maximum inducible currents. Dynamic Ca2+ and Na+ imaging assays using rat brain cortical, striatal and cerebellar neurons revealed CNS4 potentiated ion influx through native NMDA receptor activity. Overall, CNS4 is novel in chemical structure, mechanism of action and agonist concentration‐biased allosteric modulatory effect. This compound or its future analogs will serve as useful candidates to develop drug‐like compounds for the treatment of treatment‐resistant schizophrenia and major depression disorders associated with hypoglutamatergic neurotransmission.
Effect of aphid biology and morphology on plant virus transmission
Authors: Jayasinghe Wikum H , Akhter Md Shamim , Nakahara Kenji , Maruthi Midatharahally N
Published: September 2021

Aphids severely affect crop production by transmitting many plant viruses. Viruses are obligate intracellular pathogens that mostly depend on vectors for their transmission and survival. A majority of economically important plant viruses are transmitted by aphids. They transmit viruses either persistently (circulative or non‐circulative) or non‐persistently. Plant virus transmission by insects is a process that has evolved over time and is strongly influenced by insect morphological features and biology. Over the past century, a large body of research has provided detailed knowledge of the molecular processes underlying virus‐vector interactions. In this review, we discuss how aphid biology and morphology can affect plant virus transmission. © 2021 Society of Chemical Industry.
Input–output‐driven gain‐adaptive iterative learning control for linear discrete‐time‐invariant systems
Authors: Liu Chuyang , Ruan Xiaoe
Published: September 2021

For a class of linear discrete‐time‐invariant systems repetitively operated in a finite time length, an iterative correction algorithm is exploited to identify the system Markov parameters with multi‐operation inputs and outputs in obeying a criterion, of which the time order of the corrector is adaptive to the time order of the controller. Interactively, an adaptive iterative learning control is architected which composes the compensator with the approximated Markov parameters and the tracking error in sequentially minimizing a quadratic objective function of the tracking error and the compensation. Algebraic manipulation achieves that the Markov parameters correction error is monotonically declining without any step parameter selection. Further, a rigorous derivation clarifies that the time order of the learning compensator must agree to the relative degree of the system and the tracking error is linearly monotonously convergent if the Markov parameters correction error falls into an allowable range. Inspiringly, the methods and results release the confinement to both the correction and the learning ratios. In addition, a smaller learning ratio factor tolerates a larger Markov parameters correction error. Numerical experiments support the significance and the validity.
Adaptive time‐varying formation control of uncertain Euler–Lagrange systems with event‐triggered communication
Authors: Long Jiang , Wang Wei , Liu Kexin , Huang Jiangshuai
Published: September 2021

This article is concerned with time‐varying formation control of networked Euler–Lagrange systems in the presence of unknown system parameters and event‐triggered communication. Under a directed graph condition, a novel distributed adaptive formation control scheme is proposed. In order to reduce the communication burden among connected agents, a dynamic triggering condition is designed without the need of continuous monitoring of neighboring states. Zeno behavior that may exist in each agent can be rigorously excluded by introducing a dynamic variable into the triggering condition. It is shown that with the proposed control scheme, all the closed‐loop signals are uniformly bounded and all the agents' generalized coordinates can form a time‐varying formation configuration. The effectiveness of the proposed control scheme is validated with simulation results.
Bounded inputs total energy shaping for a class of underactuated mechanical systems
Authors: J. Harandi M. Reza , Taghirad Hamid D. , Molaei Amir , Guadalupe Romero Jose
Published: September 2021

Designing control systems with bounded input is a practical consideration since realizable physical systems are limited by the saturation of actuators. The actuators' saturation degrades the performance of the control system, and in extreme cases, the stability of the closed‐loop system may be lost. However, actuator's saturation is typically neglected in the design of control systems, with compensation being made in the form of overdesigning the actuator or by postanalyzing the resulting system to ensure acceptable performance. The bounded input control of fully actuated mechanical systems has been investigated in multiple studies, but it is not generalized for underactuated mechanical systems. This article proposes a systematic framework for finding the upper bound of control effort in underactuated systems, based on interconnection and the damping assignment passivity based control approach. The proposed method also offers design variables for the control law to be tuned, considering the actuator's limit. The primary difficulty in finding the control input upper bounds is the velocity‐dependent kinetic energy‐related terms. Thus, the upper bound of velocity is computed using a suitable Lyapunov candidate as a function of closed‐loop system parameters. The validity and application of the proposed method are investigated in detail through two benchmark systems simulations.
New insights into the origin and evolution of glossic features in coarse‐textured soils in northern lower Michigan (USA)
Authors: Baish Christopher J. , Schaetzl Randall J.
Published: September 2021

Although glossic horizons are widespread throughout the Great Lakes region (USA), any type of detailed empirical investigation of their genesis has not been conducted for decades. In this study, we investigated a well‐drained Haplic Glossudalf formed in calcareous till in northern Michigan and examined its glossic features across five stages of development, from nondegraded to completely degraded. Along this sequence, the glossic horizon is formed from a Bt horizon, then destroyed, evolving into an E horizon. Argillic horizon degradation is initiated from the top downward, along discrete percolation pathways. Here, temporary, highly localized, anoxic conditions favor the reduction and eluviation of Fe oxides associated with argillans. After Fe removal, clay, and to lesser extent fine silt, in the argillans become mobilized. This process results in bleached, E horizon interfingerings that penetrate the upper Bt horizon. Although eluviation of clay and fine silt is required for glossic horizon formation, their removal follows a distinct pathway from fine clay through coarse clay, and finally fine silt. This research documents the importance of redox processes at microsites in the upper Bt horizon as the destabilizing trigger for glossic horizon formation. Redox processes and microerosion may be more important than the traditionally accepted view of destabilization of clay floccules by loss of basic cations from the exchange complex. We also note that lessivage, as traditionally defined, in these soils is associated with not just clay translocation, but also fine silt.
Apparent kinetic properties of soil phosphomonoesterase and β‐glucosidase are disparately influenced by pH
Authors: Li Chongyang , Margenot Andrew J.
Published: September 2021

Extracellular enzymes catalyze organic matter transformations in soils, yet the study of soil enzymes does not typically evaluate how enzyme kinetic properties that govern activity in situ may shift with environmental parameters such as pH. To test this, we quantified changes in apparent kinetic properties (maximum catalysis rate [AppVmax] and substrate concentration that produces 50% of Vmax [AppKm]) of soil phosphomonoesterase (PME) and β‐glucosidase (BG) as a function of pH by using dual gradients of buffer pH (3–12) and substrate concentrations in a selected set of diverse soils. A third kinetic property, apparent specificity constant (AppKa = AppVmax/AppKm) was also evaluated as a function of pH. Results indicated widely differing pH optima of soil PME and BG AppVmax and AppKm, decoupling of which entailed unpredictable pH optima of AppKa. Additionally, changes in soil enzyme activity with pH may not be driven by shifts in the specificity constant because pH–AppVmax relationships are largely unrelated to co‐occurring changes in AppKa. These results invalidate the assumption that Km of a soil enzyme is constant across pH and emphasize the importance of assaying soil enzyme activities at sufficiently high (5 × Km) substrate concentrations at a given pH to avoid the mischaracterizing pH optima.
Hydrophobic Effect on Alkaline Stability of Graft Chains in Ammonium‐type Anion Exchange Membranes Prepared by Radiation‐Induced Graft Polymerization
Authors: Hamada Takashi , Zhao Yue , Yoshimura Kimio , Radulescu Aurel , Ohwada Kenji , Maekawa Yasunari
Published: September 2021

Vinylbenzyltrimethylammonium hydroxide (VBA) and styrene (St) cografted poly(ethylene‐co‐tetrafluoroethylene) anion exchange membranes (VBA/St‐AEM) were prepared by the radiation‐induced graft polymerization of chloromethylstyrene and St and sequential quaternization and anion exchange reactions. Increasing the St content in the grafts to 63 % resulted in a gradual 21 % and 34 % decrease in the conductivity and water uptake, respectively, compared to those in the VBA‐homo‐grafted AEM. AEMs with a higher St content (81 %) showed a 9 % and 18 % higher conductivity and water uptake, respectively. Small‐angle neutron scattering showed that the sudden growth of “water puddles” consisting of water‐rich nano‐domains dispersed randomly in phase‐separated hydrophilic ion channels enhanced the conductivity and water uptake. In the alkaline durability test of VBA/St‐AEM in 1 M potassium hydroxide at 80 °C for 720 h, the loss of the conductivity was suppressed from 43 % to 8 %, when the St contents in the grafts were increased from 0 % to 63 %.
Donor–Acceptor Competition via Halide Vacancy Filling for Oxygen Detection of High Sensitivity and Stability by All‐Inorganic Perovskite Films
Authors: Xing Weiwei , Yao Qianqian , Zhu Wenpeng , Jiang He , Zhang Xiaoyue , Ji Ye , Shao Jian , Xiong Weiming , Wang Biao , Zhang Bangmin , Luo Xin , Zheng Yue
Published: September 2021

Oxygen detection by organic–inorganic halide perovskites (OIHPs) has demonstrated advantages in operating temperature, response time, and reversibility over traditional materials. However, OIHPs can only sense O2 in light and the unavoidable O2 exposure during detection easily induces the degradation of OIHPs. The trade‐off between sensitivity and stability makes the OIHP‐based oxygen sensors impractical. By replacing organic groups with Cs, the compact films of all‐inorganic halide perovskites (AIHPs) that can adsorb O2 at grain boundaries in dark are developed. AIHPs show conductance increase of 1875.5% from 1 × 10−5 to 700 Torr of O2 pressure, associated with full reversibility and long‐term stability. Combining experiments and modeling, this work reveals the donor–acceptor competition via halide vacancy filling leading to the modulation of carrier concentration and mobility. This work offers understandings on oxygen sensing by perovskite materials and paves the way for further optimization of AIHPs as promising oxygen sensors with high sensitivity and stability.
Extended Barrier Lifetime of Partially Cracked Organic/Inorganic Multilayers for Compliant Implantable Electronics
Authors: Kim Kyungjin , Van Gompel Matthias , Wu Kangling , Schiavone Giuseppe , Carron Julien , Bourgeois Florian , Lacour Stéphanie P. , Leterrier Yves
Published: September 2021

Flexible and soft bioelectronics display conflicting demands on miniaturization, compliance, and reliability. Here, the authors investigate the design and performance of thin encapsulation multilayers against hermeticity and mechanical integrity. Partially cracked organic/inorganic multilayer coatings are demonstrated to display surprisingly year‐long hermetic lifetime under demanding mechanical and environmental loading. The thin hermetic encapsulation is grown in a single process chamber as a continuous multilayer with dyads of atomic layer deposited (ALD) Al2O3‐TiO2 and chemical vapor deposited Parylene C films with strong interlayer adhesion. Upon tensile loading, tortuous diffusion pathways defined along channel cracks in the ALD oxide films and through tough Parylene films efficiently postpone the hermeticity failure of the partially cracked coating. The authors assessed the coating performance against prolonged exposure to biomimetic physiological conditions using coated magnesium films, platinum interdigitated electrodes, and optoelectronic devices prepared on stretchable substrates. Designed extension of the lifetime preventing direct failures reduces from over 5 years yet tolerates the lifetime of 3 years even with the presence of critical damage, while others will directly fail less than two months at 37 °C. This strategy should accelerate progress on thin hermetic packaging for miniaturized and compliant implantable electronics.
Identification of Topotactic Surface‐Confined Ullmann‐Polymerization
Authors: Dettmann Dominik , Galeotti Gianluca , MacLean Oliver , Tomellini Massimo , Di Giovannantonio Marco , Lipton‐Duffin Josh , Verdini Alberto , Floreano Luca , Fagot‐Revurat Yannick , Perepichka Dmitrii F. , Rosei Federico , Contini Giorgio
Published: September 2021

On‐surface Ullmann coupling is an established method for the synthesis of 1D and 2D organic structures. A key limitation to obtaining ordered polymers is the uncertainty in the final structure for coupling via random diffusion of reactants over the substrate, which leads to polymorphism and defects. Here, a topotactic polymerization on Cu(110) in a series of differently‐halogenated para‐phenylenes is identified, where the self‐assembled organometallic (OM) reactants of diiodobenzene couple directly into a single, deterministic product, whereas the other precursors follow a diffusion driven reaction. The topotactic mechanism is the result of the structure of the iodine on Cu(110), which controls the orientation of the OM reactants and intermediates to be the same as the final polymer chains. Temperature‐programmed X‐ray photoelectron spectroscopy and kinetic modeling reflect the differences in the polymerization regimes, and the effects of the OM chain alignments and halogens are disentangled by Nudged Elastic Band calculations. It is found that the repulsion or attraction between chains and halogens drive the polymerization to be either diffusive or topotactic. These results provide detailed insights into on‐surface reaction mechanisms and prove the possibility of harnessing topotactic reactions in surface‐confined Ullmann polymerization.
Design thinking and creativity of colocated versus globally distributed software developers
Authors: Jolak Rodi , Wortmann Andreas , Liebel Grischa , Umuhoza Eric , Chaudron Michel R. V.
Published: September 2021

Designing software is an activity in which software developers think and make design decisions that shape the structure and behavior of software products. Designing software is one of the least understood software engineering activities. In a collaborative design setting, various types of distances can lead to challenges and effects that potentially affect how software is designed. To contribute to a better understanding of collaborative software design, we investigate how communication gaps caused by social and geographic distances affect its design thinking and the creativity of its discussions. To this end, we conducted a multiple‐case study exploring the design thinking and creativity of colocated and distributed software developers in a collaborative design setting. Compared with colocated developers, distributed developers spend less time on exploring the problem space, which could be related to different sociotechnical challenges, such as lack of awareness and common understanding. Distributed development does not seem to affect the creativity of their activities. Developers engaging in collaborative design need to be aware that problem space exploration is reduced in a distributed setting. Unless distributed teams take compensatory measures, this could adversely affect the development. Regarding the effect distance has on creativity, our results are inconclusive and further studies are needed.
Metallurgical Gradients in Structural Materials: Potential and Challenges in Creating Artificial Segregations in Medium Manganese Steel via Roll‐Bonding
Authors: Klubakov Alexej , Haase Christian , Allam Tarek , Sparrer Yannik , Pütz René D. , Krupp Ulrich , Münstermann Sebastian , Zander Daniela , Springer Hauke
Published: September 2021

Segregation of alloying elements in metallic structural materials is often considered detrimental, as it results in local inhomogeneities of microstructure and properties. However, controlled levels of segregation may be utilized to adapt and improve the bulk property profile as a composite structure of metallurgical gradients. Roll‐bonding appears as an attractive technique to study and optimize the effects of segregations in a systematic manner. Here, the feasibility of creating artificial manganese segregation bands of ±5 wt%, in a medium manganese steel of the base composition Fe–0.1C–7Mn (wt%) in an alternating sequence, is demonstrated. After intercritical annealing at 650 °C for 6 h, the Fe–0.1C–7Mn layer consists of ≈17 vol% ultrafine‐grained austenite in a ferritic matrix. The Fe–0.1C–12Mn layer contains a higher amount of austenite, while the Fe–0.1C–2Mn layer shows a fully ferritic microstructure. The differences in mechanical behavior between the roll‐bonded and reference material emphasize the role of manganese segregations in controlling the local stability of austenite under different stress states. Moreover, the corrosion investigations in 0.1 m H2SO4 reveal the preferential dissolution of adjacent high manganese containing layers. Challenges regarding the roll‐bonding methodology for creating model materials, especially the role of layer interfaces, are outlined and discussed.
Fast model‐based clustering of partial records
Authors: Goren Emily M. , Maitra Ranjan
Published: September 2021

Partially recorded data are frequently encountered in many applications and usually clustered by first removing incomplete cases or features with missing values, or by imputing missing values, followed by application of a clustering algorithm to the resulting altered dataset. Here, we develop clustering methodology through a model‐based approach using the marginal density for the observed values, assuming a finite mixture model of multivariatetdistributions. We compare our approximate algorithm to the corresponding full expectation–maximization (EM) approach that considers missing values in the incomplete dataset and makes a missing at random (MAR) assumption, as well as case deletion and imputation methods. Since only the observed values are utilized, our approach is computationally more efficient than imputation or full EM. Simulation studies demonstrate that our approach has favourable recovery of the true cluster partition compared to case deletion and imputation under various missingness mechanisms and is at least competitive with the full EM approach, even when MAR assumptions are violated. Our methodology is demonstrated on a problem of clustering gamma‐ray bursts and is implemented athttps://github.com/emilygoren/MixtClust.
Integrative taxonomy of the Selaginella helvetica group based on morphological, molecular and ecological data
Authors: Zhang Meng‐Hua , Wei Ran , Xiang Qiao‐Ping , Ebihara Atsushi , Zhang Xian‐Chun
Published: September 2021

The Eurasian and Mediterranean Selaginella helvetica group is one of the taxonomically challenging groups in the cosmopolitan lycophyte genus Selaginella. Species of the S. helvetica group are all small plants with lax strobili composed of more or less isomorphic sporophylls (isosporophylls) that are basically non‐resupinate. Owing to the similar and minute morphological characteristics, the inapplicability of chloroplast DNA markers for species delimitation and the lack of range‐wide sampling, no comprehensive study has been conducted on these species so far. In this study, we performed phylogenetic analyses based on population‐scale sampling of 126 individuals, covering the entire geographical distribution and morphological variation of this group. Five chloroplast (rbcL, psbA, atpI, atpF, atpF‐H) and two nuclear DNA regions (26S rDNA, pgiC) were used to explore species diversity of this group. The phylogeny inferred from nuclear DNA datasets revealed nine well‐supported monophyletic groups, which provided important evidence for species delimitation and called for taxonomic revision of some taxa. However, in the chloroplast phylogeny, individuals of only three species (S. denticulata, S. helvetica, S. tamamontana) formed monophyletic groups, respectively. We further investigated genome size for each species by flow cytometry and evaluated 21 morphological characteristics of 79 herbarium specimens. MaxEnt analysis was performed to predict the potential suitable distribution of each species. As a result of total evidence, 10 taxa were recognized in the S. helvetica group. The delimitation of S. denticulata, S. laxistrobila, S. nipponica, S. pallidissima, S. prostrata, and S. tamamontana was congruent with previous taxonomical treatments. We reinstated S. shensiensis as an independent species and treated S. longistrobilina as its synonym. Selaginella helvetica (s.str.) is confined to Europe and North Asia, former records of it from the Himalaya‐Hengduan mountains represent an independent species (S. jiulongensis comb. nov.). The nuclear pgiC phylogeny and flow cytometry evidence indicated that S. pseudonipponica is an allotetraploid with S. shensiensis and S. nipponica as its parents. Our results highlight that nuclear DNA markers rather than chloroplast DNA markers are more informative in delimitation of closely related species in Selaginella.
Effectiveness of PPI treatment and guideline adherence in 236 patients with eosinophilic oesophagitis—Results from the population‐based DanEoE cohort shows a low complication rate
Authors: Frandsen Line Tegtmeier , Westmark Signe , Melgaard Dorte , Krarup Anne Lund
Published: September 2021

Background

Proton pump inhibitors (PPIs) are often the first drug of choice in the treatment of eosinophilic oesophagitis (EoE), and in Denmark 8 weeks of high‐dose PPI therapy is recommended as first‐line treatment followed by rebiopsying, reflecting international recommendations.

Aims

To assess the population‐based effectiveness of PPIs in the treatment of EoE and evaluate whether patients were treated and followed according to the regional guideline.

Methods

This is a retrospective, registry‐based, DanEoE cohort study of 236 adult EoE patients diagnosed between 2007 and 2017 in the North Denmark Region. After patient file revision, the EoE diagnosis was defined according to the AGREE 2 consensus. Symptomatic PPI response was defined as complete symptom resolution and histological remission (<15 eosinophils per high‐power field).

Results

PPI treatment was initiated in 92% of the EoE patients. High‐ and low‐dose PPIs were prescribed in 55% and 45% of the cases, respectively. When treated with high‐dose PPIs, 68% of the patients were completely symptom‐free, and 49% were in histological remission. In 39% of high‐dose PPI‐treated patients, the symptomatic and histological responses were conflicting. While treated with PPIs, complications were rare, with <5% strictures in responders and <10% in non‐responders. Rebiopsying was done in 67% of the EoE patients started on PPIs.

Conclusions

High‐dose PPI treatment was effective in half of the EoE patients started on PPIs, but conflicting symptomatic and histological PPI responses were common. Complications were rare when PPIs were started. One‐third of the patients were not rebiopsied as recommended.
Temozolomide is additive with cytotoxic effect of irradiation in canine glioma cell lines
Authors: Tresch Nina Simona , Fuchs Daniel , Morandi Luca , Tonon Caterina , Rohrer Bley Carla , Nytko Katarzyna J.
Published: September 2021

Background

Similar to human glioblastoma patients, glial tumours in dogs have high treatment resistance and a guarded prognosis. In human medicine, the addition of temozolomide to radiotherapy leads to a favourable outcome in vivo as well as a higher antiproliferative effect on tumour cells in vitro.

Objectives

The aim of the study was to determine the radio‐ and temozolomide‐sensitivity of three canine glial tumour cell lines and to investigate a potential additive cytotoxic effect in combined treatment. Additionally, we wanted to detect the level of MGMT promoter methylation in these cell lines and to investigate a potential association between MGMT promoter methylation and treatment resistance.

Methods

Cells were treated with various concentrations of temozolomide and/or irradiated with 4 and 8 Gy. Radiosensitization by temozolomide was evaluated using proliferation assay and clonogenic assay, and MGMT DNA methylation was investigated using bisulfite next‐generation sequencing.

Results

In all tested canine cell lines, clonogenicity was inhibited significantly in combined treatment compared to radiation alone. All canine glial cell lines tested in this study were found to have high methylation levels of MGMT promoter.

Conclusions

Hence, an additive effect of combined treatment in MGMT negative canine glial tumour cell lines in vitro was detected. This motivates to further investigate the association between treatment resistance and MGMT, such as MGMT promoter methylation status.
The Abrikosov vortex in curved space
Authors: Albert Jan
Published: September 2021

Abstract

We study the self-gravitating Abrikosov vortex in curved space with and with-out a (negative) cosmological constant, considering both singular and non-singular solutions with an eye to hairy black holes. In the asymptotically flat case, we find that non-singular vortices round off the singularity of the point particle’s metric in 3 dimensions, whereas singular solutions consist of vortices holding a conical singularity at their core. There are no black hole vortex solutions. In the asymptotically AdS case, in addition to these solutions there exist singular solutions containing a BTZ black hole, but they are always hairless. So we find that in contrast with 4-dimensional ’t Hooft-Polyakov monopoles, which can be regarded as their higher-dimensional analogues, Abrikosov vortices cannot hold a black hole at their core. We also describe the implications of these results in the context of AdS/CFT and propose an interpretation for their CFT dual along the lines of the holographic superconductor.
Poisson gauge theory
Authors: Kupriyanov Vladislav G.
Published: September 2021

Abstract

The Poisson gauge algebra is a semi-classical limit of complete non- commutative gauge algebra. In the present work we formulate the Poisson gauge theory which is a dynamical field theoretical model having the Poisson gauge algebra as a corresponding algebra of gauge symmetries. The proposed model is designed to investigate the semi-classical features of the full non-commutative gauge theory with coordinate dependent non-commutativity Θab(x), especially whose with a non-constant rank. We derive the expression for the covariant derivative of matter field. The commutator relation for the covariant derivatives defines the Poisson field strength which is covariant under the Poisson gauge transformations and reproduces the standard U(1) field strength in the commutative limit. We derive the corresponding Bianchi identities. The field equations for the gauge and the matter fields are obtained from the gauge invariant action. We consider different examples of linear in coordinates Poisson structures Θab(x), as well as non-linear ones, and obtain explicit expressions for all proposed constructions. Our model is unique up to invertible field redefinitions and coordinate transformations.
A New Approach to Slice Analysis Via Slice Topology
Authors: Dou Xinyuan , Jin Ming , Ren Guangbin , Sabadini Irene
Published: September 2021

In this paper we summarize some known facts on slice topology in the quaternionic case, and we deepen some of them by proving new results and discussing some examples. We then show, following Dou et al. (A representation formula for slice regular functions over slice-cones in several variables,arXiv:2011.13770, 2020), how this setting allows us to generalize slice analysis to the general case of functions with values in a real left alternative algebra, which includes the case of slice monogenic functions with values in Clifford algebra. Moreover, we further extend slice analysis, in one and several variables, to functions with values in a Euclidean space of even dimension. In this framework, we study the domains of slice regularity, we prove some extension properties and the validity of a Taylor expansion for a slice regular function.
A proof of Ringel’s conjecture
Authors: Montgomery R. , Pokrovskiy A. , Sudakov B.
Published: September 2021

A typical decomposition question asks whether the edges of some graph G can be partitioned into disjoint copies of another graph H. One of the oldest and best known conjectures in this area, posed by Ringel in 1963, concerns the decomposition of complete graphs into edge-disjoint copies of a tree. It says that any tree with n edges packs $$2n+1$$

2
n
+
1

times into the complete graph $$K_{2n+1}$$

K

2
n
+
1

. In this paper, we prove this conjecture for large n.
Astrophotonics: astronomy and modern optics
Authors: Minardi S. , Harris R. J. , Labadie L.
Published: September 2021

Much of the progress in astronomy has been driven by instrumental developments, from the first telescopes to fiber fed spectrographs. In this review, we describe the field of astrophotonics, a combination of photonics and astronomical instrumentation that is gaining importance in the development of current and future instrumentation. We begin with the science cases that have been identified as possibly benefiting from astrophotonic devices. We then discuss devices, methods and developments in the field along with the advantages they provide. We conclude by describing possible future perspectives in the field and their influence on astronomy.
Sliding abrasive wear when combining WEDM conditions and polishing treatment on H13 disks over 1045 carbon steel pins
Authors: Sánchez Egea Antonio J. , Martynenko Vitaliy , Simoncelli Alejando , Serrancoli Gil , Krahmer Daniel Martínez
Published: September 2021

Forging dies are crucial in forging to manufacture accurate workpieces. These dies are generally made of AISI H steel series and hardened and tempered medium carbon alloy steel. Dies are processed by using high-speed milling + polishing or electrical discharge machining + polishing. The surface quality of the workpiece depends on the surface properties of these dies, where surface roughness, material hardness, and wear evolution of their surfaces are critical aspects to consider. This research analyzes different wire electrical discharge machining surface conditions combined with polishing treatment to describe their influence on friction and wear. Wire electrical discharge machining defines the disks’ surface properties in finishing and roughing conditions, and polishing treatment varies in time and paper sand depending on the roughness. Abbott-Firestone curves and Rsk-Rku roughness parameters characterize the surface roughness of each studied configuration. Room temperature pin-on-disk tests were performed to analyze friction coefficients and wear rate for AISI 1045 pins and AISI H13 disks. On average, the highest (0.284) and the lowest (0.201) friction coefficients were found for the combination of finishing wire electrical discharge machining + polishing and roughing wire electrical discharge machining conditions, respectively. Scanning electron microscope images were taken to describe the wear tracks and pin degradation for different sliding abrasive configurations. The diagram correlating the surface morphology and the friction coefficient predicts the wear damage on initial surface conditions, which is crucial in the forging industry to determine tool maintenance or replacement.
Equivariant splitting of the Hodge–de Rham exact sequence
Authors: Garnek Jędrzej
Published: September 2021

Let X be an algebraic curve with a faithful action of a finite group G over a field k. We show that if the Hodge–de Rham short exact sequence of X splits G-equivariantly then the action of G on X is weakly ramified. In particular, this generalizes the result of Köck and Tait for hyperelliptic curves. We discuss also converse statements and tie this problem to lifting coverings of curves to the ring of Witt vectors of length 2.
Paradoxical facilitation alongside interhemispheric inhibition
Authors: Belyk Michel , Banks Russell , Tendera Anna , Chen Robert , Beal Deryk S.
Published: September 2021

Neurophysiological experiments using transcranial magnetic stimulation (TMS) have sought to probe the function of the motor division of the corpus callosum. Primary motor cortex sends projections via the corpus callosum with a net inhibitory influence on the homologous region of the opposite hemisphere. Interhemispheric inhibition (IHI) experiments probe this inhibitory pathway. A test stimulus (TS) delivered to the motor cortex in one hemisphere elicits motor evoked potentials (MEPs) in a target muscle, while a conditioning stimulus (CS) applied to the homologous region of the opposite hemisphere modulates the effect of the TS. We predicted that large CS MEPs would be associated with increased IHI since they should be a reliable index of how effectively contralateral motor cortex was stimulated and therefore of the magnitude of interhemispheric inhibition. However, we observed a strong tendency for larger CS MEPs to be associated with reduced interhemispheric inhibition which in the extreme lead to a net effect of facilitation. This surprising effect was large, systematic, and observed in nearly all participants. We outline several hypotheses for mechanisms which may underlie this phenomenon to guide future research.