bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unterscheiden sich Patienten mit episodischer Migräne ohne Aura hinsichtlich der zervikalen muskuloskelettalen Funktion von einer symptomfreien Kontrollgruppe ohne Migräne?
Authors: Schneider Simon , Kubat Heike , Steinhoff Ute 
Published: February 2021

ZusammenfassungKopfschmerzen stellen für viele Menschen eine große Beeinträchtigung dar. Ziel der Arbeit war es, klinische Tests, die bereits bei Patienten mit Nackenschmerzen oder Whiplash Associated Disorders (WAD) angewandt werden, bei Migränepatienten ohne Aura im Vergleich mit einer symptomfreien Kontrollgruppe durchzuführen.Im Rahmen einer Querschnittstudie wurden die Ergebnisse aus 2 Fragebögen und 6 klinischen Tests von Patienten mit episodischer Migräne (n = 23) mit den Ergebnissen einer symptomfreien Kontrollgruppe (n = 15) verglichen. Die Ergebnisse zeigten hoch signifikante Unterschiede (p < 0,001) zwischen den Gruppen für die Fragebögen und signifikante Unterschiede bei den Kopf-Auge-Bewegungskontrolltests, dem Joint-Position-Error-Test, Zervikalen Flexions-Rotations-Test, Fukuda-Stepping-Test (Merkmal > 45° Körperrotation) sowie dem Kraniozervikalen Flexionstest. Kein signifikanter Unterschied (p > 0,05) zeigte sich bei dem Fukuda-Stepping-Test (Merkmal > 1 m Vorwärtsgehen) sowie für den Single-Leg-Stance.Verschiedene sensomotorische, okulomotorische und muskuloskelettale Auffälligkeiten konnten bei Patienten mit episodischer Migräne ohne Aura in dieser Studie aufgezeigt werden. Für therapeutische Prozesse sollten daher die Tests in Untersuchungsabläufe integriert werden. Es bedarf jedoch weiterer Studien, um die Effektivität von Therapien, die auf diese Dysfunktionen Einfluss nehmen, zu bewerten.
Functionalized Cyclopropanes as Versatile Intermediates for the Diversity-Oriented Synthesis of γ-Lactones, γ-Lactams and δ-Lactams
Authors: Sá Marcus M. , Maximiano Adrielle P. , Ramos Giovana S. , Marques Marcelo V. 
Published: February 2021

AbstractA two-step procedure for the preparation of cyclopropanecarboxaldehyde-1,1-diester from a γ,δ-epoxyester and its synthetic versatility are described herein. The epoxide ring-opening/cyclopropanation process occurs in the presence of Mg(ClO4)2 under heating, resulting in cyclopropanemethanol-1,1-diester in 65% yield. A mild TEMPO-mediated oxidation of this substrate readily generated the corresponding aldehyde in 75% yield, which was applied in the one-pot synthesis of four cyclopropylidene-γ-lactams and three δ-lactams. In addition, vinylcyclopropanes were obtained through the Wittig reaction of the aldehyde with phosphonium salts and used as precursors for tetrahydrofurans.
A New “Denervation” Technique for Painful Arthritic Wrist
Authors: Rigoni Massimo , Raggi Massimiliano , Speri Luca 
Published: February 2021

AbstractWrist denervation is, by the way, one of the most performed and long-lasting surgical technique for wrist arthritis. Despite many progresses in upper extremity joint arthroplasty, wrist arthritis remains difficult to treat specially in young patients and heavy manual workers. The aim of this technical article is to describe a new outpatient's procedure in which applying pulsed radio frequency on nerve structure of the wrist could achieve similar clinical results of a wrist denervation without surgical incision.
Business groups and the study of international business: A Coasean synthesis and extension
Authors: Dau Luis Alfonso , Morck Randall , Yeung Bernard Yin 
Published: February 2021

AbstractThis paper harmonizes the business group literature in international business and across relevant fields within a unified theoretical framework. Business groups (firms under common control but with different, if overlapping, owners) are economically important in much of the world. Business groups’ economic significance co-evolves with their economies' institutions and market environments, patterns of particular interest to international business scholars. The vast literature on business groups raises discordant perspectives. This paper first proposes a unifying definition and provides a list of stylized historical observations on business groups across different parts of the world. It then develops a Coasean framework to harmonize seemingly disparate views from the literature by building on recent surveys and the stylized historical patterns of business groups. We enlist two concepts – fallacies of composition/decomposition and time inconsistency – to harmonize these perspectives. This yields a theoretical framework for understanding business groups that mobilizes concepts long-used to understand multinational enterprises: the economy's market and hierarchical transaction costs, openness, and their dynamic interactions. We then apply this framework to globalization and business group internationalization. This work leads to an overarching research agenda encompassing seemingly inconsistent prior work.
A bibliometric study of research topics, collaboration, and centrality in the iterated prisoner’s dilemma
Authors: Glynatsi Nikoleta E. , Knight Vincent A. 
Published: February 2021

AbstractThis manuscript explores the research topics and collaborative behaviour of authors in the field of the Prisoner’s Dilemma using topic modeling and a graph theoretic analysis of the co-authorship network. The analysis identified five research topics in the Prisoner’s Dilemma which have been relevant over the course of time. These are human subject research, biological studies, strategies, evolutionary dynamics on networks and modeling problems as a Prisoner’s Dilemma game. Moreover, the results demonstrated the Prisoner’s Dilemma is a field of continued interest, and that it is a collaborative field compared to other game theoretic fields. The co-authorship network suggests that authors are focused on their communities and that not many connections across the communities are made. The most central authors of the network are the authors connected to the main cluster. Through examining the networks of topics, it was uncovered that the main cluster is characterised by the collaboration of authors in a single topic. These findings add to the bibliometrics study in another field and present new questions and avenues of research to understand the reasons for the measured behaviours.
Neutron total scattering investigation on the dissolution mechanism of trehalose in NaOH/urea aqueous solution
Authors: Qin Hong , Ma Changli , Gärtner Sabrina , Headen Thomas F. , Zuo Taisen , Jiao Guisheng , Han Zehua , Imberti Silvia , Han Charles C. , Cheng He 
Published: February 2021

Trehalose is chosen as a model molecule to investigate the dissolution mechanism of cellulose in NaOH/urea aqueous solution. The combination of neutron total scattering and empirical potential structure refinement yields the most probable all-atom positions in the complex fluid and reveals the cooperative dynamic effects of NaOH, urea, and water molecules in the dissolution process. NaOH directly interacts with glucose rings by breaking the inter- and intra-molecular hydrogen bonding. Na+, thus, accumulates around electronegative oxygen atoms in the hydration shell of trehalose. Its local concentration is thereby 2–9 times higher than that in the bulk fluid. Urea molecules are too large to interpenetrate into trehalose and too complex to form hydrogen bonds with trehalose. They can only participate in the formation of the hydration shell around trehalose via Na+ bridging. As the main component in the complex fluid, water molecules have a disturbed tetrahedral structure in the presence of NaOH and urea. The structure of the mixed solvent does not change when it is cooled to −12 °C. This indicates that the dissolution may be a dynamic process, i.e., a competition between hydration shell formation and inter-molecule hydrogen bonding determines its dissolution. We, therefore, predict that alkali with smaller ions, such as LiOH, has better solubility for cellulose.
A spinorial proof of the rigidity of the Riemannian Schwarzschild manifold
Authors: Raulot Simon 
Published: February 2021

Abstract
We revisit and generalize a recent result of Cederbaum (Cederbaum in preparation; Cederbaum 2017 Oberwolfach Report) concerning the rigidity of the Schwarzschild manifold for spin manifolds. This includes the classical black hole uniqueness theorems (Bunting and Masood-ul-Alam 1987 Gen. Relativ. Gravit.
19 147; Gibbons, Ida and Shiromizu 2002 Phys. Rev. Lett.
89 041101; Hwang 1998 Geom. Dedicata
71 5) as well as the more recent uniqueness theorems for photon spheres (Cederbaum 2015 Contemp. Math.
667 86; Cederbaum and Galloway 2017 Commun. Anal. Geom.
25 303; Cederbaum and Fehrenbach personal communication).
A penalty-free approach to PDE constrained optimization: application to an inverse wave problem
Authors: Hoffmann Alexandre , Monteiller Vadim , Bellis Cédric 
Published: February 2021

Abstract
Inverse wave problems (IWPs) amount in non-linear optimization problems where a certain distance between a state variable and some observations of a wavefield is to be minimized. Additionally, we require the state variable to be the solution of a model equation that involves a set of parameters to be optimized. Typical approaches to solve IWPs includes the adjoint method, which generates a sequence of parameters and strictly enforces the model equation at each iteration, and, the wavefield reconstruction inversion (WRI) method, which jointly generates a sequence of parameters and state variable but does not strictly enforce the model. WRI is considered to be an interesting approach because, by virtue of not enforcing the model at each iteration, it expands the search space, and can thus find solutions that may not be found by a typical adjoint method. However, WRI techniques generally requires the tuning of a penalty parameter until the model equation is considered satisfied. Alternatively, a fixed penalty parameter can be chosen but, in such case, it is impossible for the algorithm to find a solution that satisfies the model equation exactly. In the present work, we present a, to our knowledge, novel technique of WRI type which jointly generates a sequence of parameters and state variable, and which loosely enforces the model. The method is based on a TR-SQP method which aims at minimizing, at each iteration, both the residual relative to the linearized model and a quadratic approximation of the cost functional. Our method approximately solves a sequence of quadratic subproblems by using a Krylov method. The Hessian-vector product is computed using the second-order adjoint method. The method is demonstrated on a synthetic case, with a configuration relevant to medical imaging.
Effective theory for self-interacting dark matter and massive spin-2 mediators
Authors: Kang Yoo-Jin , Lee Hyun Min 
Published: February 2021

Abstract
We consider the effective theory for self-interacting dark matter with arbitrary spin and go beyond the previous discussion in the literature by introducing a massive spin-2 particle as the mediator for dark matter (DM) self-scattering. We present effective self-interactions for DM in the leading order expansions with momentum transfer and DM velocity. We compare the Born cross section and the non-perturbative cross section in the leading-order approximation of the effective Yukawa interaction. As a result, we find that there is a wide range of DM and spin-2 particle masses for velocity-dependent self-scattering to solve small-scale problems in galaxies and to satisfy the bounds from galaxy clusters at the same time.
Automated remote decision-making algorithm as a primary triage system using machine learning techniques
Authors: Kim Dohyun , Chae Jewook , Oh Yunjung , Lee Jongshill , Kim In Young 
Published: February 2021

Abstract

Objective. An objective and convenient primary triage procedure is needed for prioritizing patients who need help in mass casualty incident (MCI) situations, where there is a lack of medical staff and available resources. This study aimed to develop an automated remote decision-making algorithm that remotely categorize a patient’s emergency level using clinical parameters that can be measured with a wearable device. Approach. The algorithm was developed according to the following procedures. First, we used the National Trauma Data Bank data set, a large open trauma patient data set assembled by the American College of Surgeons (ACS). In addition, we performed pre-processing to exclude data when the vital sign or consciousness indicator value was missing or physiologically in an abnormal range. Second, we selected the T-RTS method, which classifies emergency levels into four classes (Delayed, Urgent, Immediate and Dead), as the primary outcome. Third, three machine learning methods widely used in the medical field, logistic regression, random forest, and deep neural network (DNN), were applied to build the algorithm. Finally, each method was evaluated using quantitative performance indicators including the macro-averaged f1 score, macro-averaged mean absolute error (MMAE), and the area under the receiver operating characteristic curve (AUC). Main results. For total sets, the logistic regression had a macro-averaged f1 score of 0.673, an MMAE of 0.387 and an AUC value of 0.844 (95% CI, 0.843–0.845), while the random forest and DNN had macro-averaged f1 scores of 0.783 and 0.784, MMAEs of 0.297 and 0.298 and AUC values of 0.882 (95% CI, 0.881–0.883) and 0.883(95% CI, 0.881–0.884), respectively. Significance. In a comprehensive analysis of these results, our algorithm demonstrated a viable approach that could be practically adopted in an MCI. In addition, it can be employed to transfer patients and to redistribute available resources according to their priorities.
4D flow MRI: impact of region of interest size, angulation and spatial resolution on aortic flow assessment
Authors: Casciaro M E , Pascaner A F , Guilenea F N , Alcibar J , Gencer U , Soulat G , Mousseaux E , Craiem D 
Published: February 2021

Abstract

Objectives. In cardiovascular magnetic resonance, the 3D time-resolved phase-contrast technique, also known as 4D flow, is gaining increasing attention due to applications that exploit three-directional velocity encoding throughout the cardiac cycle. Blood flow volume assessment usually requires an expert to draw regions of interest (ROI) around the vessel cross section, whereas the errors involved in this estimation have not been thoroughly investigated. Our objective is to quantify the influence of ROI sizing, angulation and spatial resolution of the reconstructed plane employed in blood flow measurements using 4D flow. Approach. Three circular ROIs were drawn around the ascending, arch and descending aorta of healthy volunteers (n = 27) and patients with a dilated ascending aorta or bicuspid valve (n = 37). We applied systematic changes of ROI diameter (up to ±10%), tilt angle (up to ±25°) and spatial resolution (from 0.25 to 2 mm) of the reconstructed oblique planes, calculating the effects on net, forward and backward blood flow volumes. Main results. Patients had a larger ascending aorta than healthy volunteers with similar ages and male sex proportion (60 ± 15 y.o. vs 58 ± 16 y.o. and 84% vs 70%, respectively). Higher forward and backward flow volumes were observed in the ascending aorta and the aortic arch of the patients with respect to controls (p < 0.001), whereas net volumes were similar: 74.0 ± 20.8 ml versus 75.7 ± 21.8 ml (p = 0.37), respectively. The ascending aorta was the most sensitive to ROI modifications. Changes of ±10% in the ROI diameter and ±25° in tilt angles produced flow volume differences of up to 9 ml (10%) and 18 ml (15%) in controls and patients, respectively. Modifying the reconstructed planes spatial resolution produced flow volume changes below 2 ml. Significance. Since the setting of the ROI size and plane angle could produce errors that represent up to 20% of the forward and/or backward aortic flow volume, a good standardization for vessel segmentation and plane positioning is desirable.
Structural parameter study of dual transducers-type ultrasonic levitation-based transportation system
Authors: Mu Guanyu , Zhao Jie , Dong Huijuan , Wu Jiang , Grattan Kenneth Thomas Victor , Sun Tong 
Published: February 2021

Abstract
Having a continuous mode of transportation, in the manufacturing and pharmaceutical industries, is desirable and this facilitated by the usage of dual transducer-type ultrasonic levitation-based transportation systems. It is well known that the structural and electrical parameters determine what can be transported continuously, but the relationships between these important parameters are still not clear. In this study, the vibrating plate length and the phase shift between the two transducers were investigated as both of these are key parameters for the transportation system, and affect the standing wave ratios (SWRs), the acoustic radiation forces, and consequently the way the transportation system operates. Through numerical analysis and experimental verification, it can be seen that when the sum or difference of the spatial phase difference (determined by the vibrating plate length) and the phase shift is equal to 180° × (1 + 2n) (where n is an integer), except for the spatial phase difference of 180°·m (where m is also an integer) and the SWRs approaches unity, all this implying that traveling waves (TWs) are dominantly excited on the vibrating plate. As a consequence, the TW-induced acoustic radiation force, which greatly exceeds the standing wave-induced force, causes the continuous transportation of the particle being moved in the sound field. This paper not only clarifies the requirements for generating this continuous transportation, but also provides valuable information on the practical design of such a transportation system.
Proton fraction in neutron star matter: dynamical mean-field approach
Authors: Velikanov Maksim , Rubtsov Alexey N , Krippa Boris 
Published: February 2021

Abstract
Dynamical mean field theory (DMFT) is used to study neutron matter, both with and without admixture of the proton fraction. The system is approximated by the lattice Hubbard model. The corresponding equation of state as a function of temperature/density/asymmetry is investigated. The results are compared with the standard mean field (MF) approach where the effect of local correlations is neglected. Whereas the influence of the correlations on the properties of a pure neutron matter is found to be moderate, it becomes strong when the proton admixture is taken into account. In particular, we calculate the proton fraction, energy density and pressure in outer core of neutron stars, taking into account the beta equilibrium condition. The DMFT predicts that the proton fraction is several times the MF based calculations, whereas the DMFT results for energy density and pressure are 30%–40% lower than the corresponding MF estimates. Physical implications of our findings for a neutron star dynamics are discussed.
Exciton radiative lifetime in a monoatomic carbon chain
Authors: Kutrovskaya Stella , Demirchyan Sevak , Osipov Anton , Baryshev Stepan , Zasedatelev Anton , Lagoudakis Pavlos , Kavokin Alexey 
Published: February 2021

Abstract
Linear carbon-based materials such as polyyne and cumulene oligomers provide a versatile platform for nano-physics and engineering. Direct gap quasi-1D polyyne structures are promising for the observation of strong and unusual excitonic effects arising due to the two-dimensional quantum confinement. Recently, we reported on the observation of sharp exciton peaks in low temperature photoluminescence spectra of polyyne chains (Kutrovskaya S et al 2020 Nano Lett.
20 6502–9). Here, we analyze the time-resolved optical response of this system. We extend the non-local dielectric response theory to predict the exciton radiative lifetime dependence on the band-gap value and on the length of the chain. A good agreement between the experiment and the theory is achieved.
Double-logarithmic nonlinear electrodynamics
Authors: Gullu Ibrahim , Mazharimousavi S Habib 
Published: February 2021

Abstract
A new model of nonlinear electrodynamics is introduced and investigated. The theory carries one dimensionful parameter β as in Born-Infeld electrodynamics. It is shown that the dual symmetry and dilatation (scale) symmetry are broken in the proposed model. The electric field of a point-like charge is derived for this model, showing that it is non-singular at the origin. Using this electric field, the static electric energy of a point-like charge is calculated. In the presence of an external magnetic field, the theory shows a phenomenon known as vacuum birefringence. The refraction index of two polarizations, parallel and perpendicular to the external magnetic induction field, are calculated. The canonical and symmetrical Belinfante energy-momentum tensors are obtained. Using the causality and unitarity principles, the regions where the theory becomes causal and unitary are found.
Modeling and analysis of high shear viscoelastic Ellis thin liquid film phenomena
Authors: Alam M Kamran , Memon K N , Siddiqui A M , Shah S F , Farooq Muhammad , Ayaz Muhammad , Nofal Taher A , Ahmad Hijaz 
Published: February 2021

Abstract
In this paper, the Steady state thin layer flow of a viscoelastic Ellis fluid in contact with a vertical cylinder for drainage and lift problems is examined. Closed form solutions are obtained from the resulting differential equation using the well known binomial series technique. Furthermore, during the analysis of high shear viscoelastic Ellis liquid film, special cases including power law, Bingham plastic and Newtonian fluid film have been retrieved. The Physical quantities such as vorticity vector, thickness about the fluid film, flow rate and average velocity have been investigated for both the lift and drainage physical phenomena. The Thickness of the Ellis fluid film on cylindrical surfaces has been calculated. The velocity profiles for the phenomena are graphically sketched and during the study it is investigated that at the high shear rates the model reduces to the power law model and adequately low shear stress the model reduces to a Newtonian model. From the results it is noticed that, with increase in α and R, velocity increases for drainage case while decreases for lift case. Velocity profile for Newtonian and Bingham plastic fluids is calculated and it is observed that, the drainage velocity profile has increasing effect with the increase of r and has reverse effect for lift case with increasing r. The variation of n for power law model in drainage and lift have been plotted, where it is investigated that velocity of fluid layer grow up.
Photocurrent improvement of an ultra-thin silicon solar cell using cascaded cylindrical shape plasmonic nanoparticles
Authors: Heidarzadeh Hamid , Bahador Hamid 
Published: February 2021

Abstract
The main aim of this research work is to significantly improve the photocurrent of an ultra-thin silicon solar cell. Here, cylindrical shape cascaded plasmonic nanoparticles are used to design an ultra-thin silicon solar cell. The main idea is to manipulate the absorption spectra of a thin absorber by applying four cascaded cylindrical shape nanoparticles from different materials with different radii and heights. At first, a cell with one nanoparticle at the surface and another one with a nanoparticle at the bottom side are simulated, and their photocurrents are determined. Then, a cell with four cascaded Ag, Al, Ag-Al, and Al-Ag nanoparticles is simulated. The maximum photocurrent density and efficiency of 23.46 mA cm−2 and 13.95%, respectively, are obtained for a cell in which Ag and Al’s nanoparticles are used alternatively from top to bottom. The photocurrent density is 8.2 mA cm−2 for a cell without any nanoparticles. The simulated results show that cascaded nanoparticles significantly enhance the photocurrent. Finally, the generation rate is presented at different wavelengths.