bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orbital solutions derived from radial velocities and time delays for four Kepler systems with A/F-type (candidate) hybrid pulsators
Authors: Lampens P. , Vermeylen L. , Frémat Y. , Sódor Á. , Skarka M. , Samadi-Ghadim A. , Bognár Zs. , Lehmann H. , De Cat P. , Goswami A. , Dumortier L. 
Published: January 2021

Context. The presence of A/F-type Kepler hybrid stars extending across the entirety of the δ Scuti – γ Doradus instability strips and beyond remains largely unexplained. In order to better understand these particular stars, we performed a multi-epoch spectroscopic study of a sample of 49 candidate A/F-type hybrid stars and one cool(er) hybrid object detected by the Kepler mission. We determined a lower limit of 27% for the multiplicity fraction. For six spectroscopic systems, we also reported long-term variations in the time delays (TDs). For four systems, the TD variations are fully coherent with those of the radial velocities (RVs ) and can be attributed to orbital motion.
Aims. We aim to improve the orbital solutions for those spectroscopic systems with long orbital periods (order of 4–6 years) among the Kepler hybrid stars that we continued to observe.
Methods. The orbits are computed based on a simultaneous modelling of the RVs obtained with high-resolution spectrographs and the photometric TDs derived from time-dependent frequency analyses of the Kepler light curves.
Results. We refined the orbital solutions of four spectroscopic systems with A/F-type Kepler hybrid component stars: KIC 4480321, 5219533, 8975515, and KIC 9775454. Simultaneous modelling of both data types analysed together enabled us to improve the orbital solutions (all), obtain more robust and accurate information on the mass ratio (some for the first time), and identify the component with the short-period δ Sct-type pulsations (all). The information gained is maximized when one of the components, generally the one exhibiting the δ Sct-type pulsations, is a fast rotator. In several cases, we were also able to derive new constraints for the minimum component masses. From a search for regular frequency patterns in the high-frequency regime of the Fourier transforms of each system, we found no evidence of tidal splitting among the triple systems with close (inner) companions. However, some systems exhibit frequency spacings that can be explained by the mechanism of rotational splitting.
Ultrasound-Promoted Synthesis of Spirocyclopropanes from Switchable Starting Materials via Azomethine Ylide [3+2]-Cycloaddition
Authors: Yavari Issa , Sheikhi Sara , Sheykhahmadi Jamil , Taheri Zohreh , Halvagar Mohammad Reza 
Published: January 2021

AbstractAn ultrasound-promoted green protocol to access a new series of spirocyclopropanes from indeno[1,2-b]quinoxaline derivatives and azomethine ylides, generated in situ from the iodine-catalyzed reaction of acetophenones as well as of 2-methylquinoline with pyridine in the presence of a base, is described. These transformations proceed via a spirocyclopropanation reaction followed by elimination of pyridine. Clear evidence for the structure of a spirocyclopropane-linked indenoquinoxaline derivative was obtained from single-crystal X-ray analysis. The most important feature of this reaction is the fact it forms three stereogenic centers, one of which is quaternary, with excellent selectivity.
Efficient Synthesis of 7,8-Dihydro-6H-benzo[c]chromen-6-one Derivatives by Base-Mediated Chemoselective Annulation of Alkylidene Malononitriles with α,β-Unsaturated Coumarins
Authors: Alizadeh Abdolali , Farajpour Behnaz , Khanpour Mojtaba 
Published: January 2021

AbstractAn efficient and chemoselective synthesis of biologically valuable 7,8-dihydro-6H-benzo[c]chromen-6-ones is described. In this method, neither a metal catalyst nor expensive starting materials are needed, and the products can be purified by simple filtration and washing with EtOH. Readily available starting materials, green and mild conditions, synthetically useful yields, and operational simplicity are some highlighted advantages of this unprecedented transformation.
Nickel Hydride Catalyzed Cleavage of Allyl Ethers Induced by Isomerization
Authors: Berkefeld Andreas , Fleischer Ivana , Kathe Prasad M. 
Published: January 2021

AbstractThis report discloses the deallylation of O- and N-allyl functional groups by using a combination of a Ni-H precatalyst and excess Brønsted acid. Key steps are the isomerization of the O- or N-allyl group through Ni-catalyzed double-bond migration followed by Brønsted acid induced O/N–C bond hydrolysis. A variety of functional groups are tolerated in this protocol, highlighting its synthetic value.
Prevalence and Likelihood Ratio of Six Objective Signs among Good Responders to Natrum muriaticum: Multi-centre Observational Assessment
Authors: Eizayaga José E. , Waisse Silvia , Rutten Lex , Klein-Laansma Christien , Motura Astrid 
Published: January 2021

AbstractBackground The reliability of homeopathic prescriptions may increase through resource to objective signs and guiding symptoms with significant positive likelihood ratio (LR). We estimated LR for six objective signs attributed to the homeopathic medicine Natrum muriaticum (Nat-m).Methods In this multi-centre observational assessment, we investigated the prevalence of six signs in the general patient population and among good responders to Nat-m in daily homeopathic practice. Next, we calculated LR for these six signs.Results Data from 36 good responders to Nat-m and 836 general population patients were compared. We found statistically significant positive LR (95% confidence interval) for signs such as lip cracks (1.94; 1.15 to 3.24), recurrent herpes (2.29; 1.20 to 4.37), hairline eruptions (2.07; 1.03 to 4.18), and dry hands (2.13; 1.23 to 3.69).Conclusions Objective signs with significant positive LR might increase the reliability of homeopathic prescriptions. Further studies are warranted to confirm the validity of this approach.
Venous Thromboembolism in Cancer Patients Undergoing Chemotherapy: Risk Factors and Prevention
Authors: Prandoni Paolo , Campello Elena 
Published: January 2021

AbstractAmbulatory cancer patients undergoing chemotherapy are at a substantial risk for venous thromboembolism (VTE) over the course of therapy and beyond it. Factors accounting for this risk include the activation of extrinsic and intrinsic coagulation pathways, platelet activation, impaired fibrinolysis, use of catheters, infusion of blood products, and thrombogenic potential of several chemotherapeutic drugs. A few stratification models can help identify patients at a higher risk of chemotherapy-associated VTE, who may benefit from preventive strategies. Although low-molecular-weight heparins (LMWHs) effectively reduce the risk of VTE, current guidelines recommend against their routine use. Based on the results of recent randomized controlled clinical trials, the administration of prophylactic doses of the novel direct oral anticoagulants (DOACs) to ambulatory cancer patients undergoing chemotherapy has the potential to offer an effective and safe protection against VTE, obviating the inconveniences of heparins. Except for patients in whom the novel drugs are unsuitable or are contraindicated, in all other patients LMWHs should be replaced by low-dose DOACs.
Is Standing Coronal Long-Leg Alignment View Effective in Predicting the Extent of Medial Soft Tissue Release in Varus Deformity during Total Knee Arthroplasty?
Authors: Sajjadi Mohammadreza Minator , Okhovatpour Mohammad Ali , Safaei Yaser , Faramarzi Behrooz , Zandi Reza 
Published: January 2021

AbstractThe aim of this study was to assess the predictive value of the femoral intermechanical-anatomical angle (IMA), mechanical lateral distal femoral angle (mLDFA), medial proximal tibia angle (MPTA), femorotibial or varus angle (VA), and joint line convergence angle (CA) in predicting the stage of the medial collateral ligament (MCL) during total knee arthroplasty (TKA) of varus knee. We evaluated 229 patients with osteoarthritic varus knee who underwent primary TKA, prospectively. They were categorized in three groups based on the extent of medial soft tissue release that performed during TKA Group 1, osteophytes removal and release of the deep MCL and posteromedial capsule (stage 1); Group 2, the release of the semimembranosus (stage 2); and Group 3, release of the superficial MCL (stage 3) and/or the pes anserinus (stage 4). We evaluated the preoperative standing coronal hip-knee-ankle alignment view to assessing the possible correlations between the knee angles and extent of soft tissue release. A significant difference was observed between the three groups in terms of preoperative VA, CA, and MPTA by using the Kruskal–Wallis test. The extent of medial release increased with increasing VA and CA as well as decreasing MPTA in preoperative long-leg standing radiographs. Finally, a patient with a preoperative VA larger than 19, CA larger than 6, or MPTA smaller than 81 would need a stage 3 or 4 of MCL release. The overall results showed that the VA and MPTA could be useful in predicting the extent of medial soft tissue release during TKA of varus knee.
Comparison of Minimally Invasive Operative Treatment with Conservative Treatment for Acute, Minimally Displaced Scaphoid Fractures at 12 Months' Follow-up
Authors: Fyllos Apostolos , Komnos George , Koutis Athanasios , Bargiotas Konstantinos , Varitimidis Sokratis , Dailiana Zoe 
Published: January 2021

Abstract
Background Minimally displaced scaphoid fractures can be challenging to diagnose and treat. Cannulated scaphoid screws have made percutaneous stabilization highly effective.
Questions Would minimally invasive operative treatment of minimally displaced scaphoid fractures yield faster return to work when compared with patients treated conservatively? How do functional and patient satisfaction scores compare between the two groups at 12-months follow-up?
Patients and Methods Records from 18 patients (mean age 28.6 years) treated surgically were retrospectively reviewed and compared with a group of 10 patients (mean age 33.3 years, p = 0.74) treated nonoperatively. Inclusion criteria were a minimum follow-up period of 12 months and radiographic union. Time to return to work was compared between groups. At 12 months' follow-up, wrist range of motion (ROM) and grip strength were compared, as well as pain, satisfaction, and overall wrist function were evaluated by the visual analogue scale (VAS) and the Mayo modified wrist score (MMWS).
Results The mean time to return to work for the operated group was 39.75 days, while for the nonoperated group it was 88.14 days (p = 0.002). At the 12 months' follow-up, mean ROM, grip strength, and VAS score did not differ between groups. The mean MMWS was 98.75 for the operated group and 87.5 for the nonoperated group, indicating a better result in patients treated operatively (p = 0.03). In addition, two failures of instrumentation were recorded, a seldom seen complication.
Conclusion Percutaneous fixation of minimally displaced scaphoid fractures allows faster return to work and leaves patients more satisfied with their wrist function compared with plaster immobilization at 12 months' follow-up.
Level of evidence This is a Level III, retrospective, case–control study.
High Incidence of Osteoarthritis Observed in Patients at Short- to Midterm Follow-Up after Delayed Multiligament Knee Reconstruction
Authors: Sobrado Marcel Faraco , Giglio Pedro Nogueira , Bonadio Marcelo Batista , Pecora Jose Ricardo , Gobbi Riccardo Gomes , Angelini Fabio Janson , Helito Camilo Partezani 
Published: January 2021

AbstractThe aim of this study was to evaluate the incidence of knee osteoarthritis, failure rate of reconstruction, and clinical outcomes of patients with chronic multiligament knee injuries subjected to surgical treatment. Sixty-two patients with chronic knee dislocation subjected to multiligament reconstruction between April 2008 and July 2016 were evaluated, with a minimum follow-up of 24 months. Anteroposterior and lateral radiographs were performed in the pre- and last postoperative evaluation; the progression of degenerative changes according to the Kellgren-Lawrence classification (KL) was assessed. The Schenck classification, Knee Injury and Osteoarthritis Outcome Score (KOOS), time between injury and surgery, type of postoperative rehabilitation protocol (brace vs. external fixator), and physical examination for ligament instability were also evaluated. Univariate and multivariate analysis were performed, p <0.05 was considered significant. Fifty-two (83.9%) patients were men and 16.1% (n = 10) were women, with a mean age of 38.8 ± 1.3 years. The time from injury to surgery was 31.1 ± 6.1 months, and the follow-up time was 6.1 ± 0.5 years. The mean final KOOS was 79.3 ± 10.4 and the overall reconstruction failure occurred in 25.8%. Of all patients, 64.5% (n = 40) presented a KL classification of ≥2 and were defined as having radiographic osteoarthritis (OA). As 11.7% (n = 7) also presented arthritis in the contralateral knee, in 53.2% (n = 33) the progression was most likely due to the initial injury. The failure of ligament reconstruction or residual instability was present in 15 (35.7%) of patients with OA, and only one patient (4.5%) without OA. In the multivariate analysis, only reconstruction failure was an independent predictor of OA (odds ratio = 13.2 [p = 0.028]). There is a high incidence of knee OA following ligament reconstruction for chronic multiligament knee injuries. Ligament reconstruction failure was the only independent predictor for the development of OA in our study.
Factors Influencing Ultrasonic Wave Propagation in Tourmaline
Authors: Gai Xinghui , Chen Kairen , Yang Dewu , Zhou Guojun , Zhao Changchun , Zhao Pengfei , Dong Pengsheng , Fan Zhenjun 
Published: January 2021

Abstract
P-wave propagation velocity in tourmaline is related to its microstructure, chemical composition, temperature, and other factors. The effects of tourmaline density, FeO contents, and temperature on P-wave propagation were studied in this paper. The results show that the temperature affects P-wave velocity due to the temperature dependence of thermal expansion, and elastic and dielectric constants of tourmaline. The propagation velocity of P-wave decreases with increasing porosity or FeO content. The content of FeO in tourmaline can be used as the basis for the determination of different species of tourmaline, which provides an important experimental basis for ultrasonic waves to be used as a nondestructive testing technology to distinguish different types of tourmaline.
A Study on the Nuclear Shell Effects near the Drip Line Region
Authors: Shen Shuifa , Yan Yupeng , He Zhixiong , Song Yaodong , Gao Weiwei , Lan Jieqing 
Published: January 2021

Abstract
A theoretical method which is applied to examine the shell effects is presented, namely, by calculating the particle number fluctuation in the framework of the relativistic mean-field model with the BCS pairing. We find that the size of the particle number fluctuation is related to the nuclear shell structure. Based on this method, the disappearance of conventional magic numbers and the presence of new magic numbers near drip-line region are studied.
Study on Acoustics Abnormal Refraction Based on Generalized Snell’s Law
Authors: Chu Q Q , Hu Y , Lin W 
Published: January 2021

Abstract
In recent years, metamaterials have been used to manipulate wave fronts in various ways, affecting the propagation of waves, and exerting different its application values. Based on the generalized Snell’s law derived from Fermat’s principle, the article takes advantage of the high integration of metamaterials at the sub-wavelength scale to construct an acoustic metasurface artificial structure and expands it to a periodic type. Under the condition of ensuring the constant transmittance when acoustic wave passes through the interface of the two media, through the phase modulation of the acoustic wave on the surface of the structure, the strange phenomenon of abnormal refraction is generated, and the arbitrary manipulation of the wave is realized effectively.
Thermodynamic Process Simulation and Evaluation on Surface-Mounted Evaporative Cooling System
Authors: Shi Yitao , Cao Rui , Ruan Lin 
Published: January 2021

Abstract
The change of exergy has a direct impact on the circulation head of the surface-mounted evaporative cooling system that relies on the change of vapor-liquid density for circulating cooling. In this paper, the circulation system of the surface-mounted evaporative cooling system is taken as the research object. Based on the second law of thermodynamics, an exergy analysis model of main equipment is established to analyze and evaluate the characteristics of exergy change of the system. The research results show that under different thermal loads, the exergy efficiency is less than 70%, the exergy loss in the liquid box is relatively large, and the main irreversible exergy loss in liquid box occurs in the vapor-liquid boiling process, which will restrict the cooling capacity of the system. This study provides a theoretical basis for further optimizing the flow heat transfer process of the surface-mounted evaporative cooling system.
Designing Neutron Shield Material for D-T Neutron Generator
Authors: Li Xianglong , Cong Meilin , Yang Guifu , Su Weihua 
Published: January 2021

Abstract
If hydrogen-rich material is used to shield the 14 MeV neutrons produced by D-T neutron generator whose neutron yield is 108 n/s, its thickness must be more than 74 cm to make dose of neutron radiation less than 0.025 mSv/h. For decrease the thickness, two layers material composed of boron-polyethylene and copper used as 14 MeV neutron shielding material. The calculation result shows that the minimum thickness of the two layers material is 52 cm, in which the thicknesses of copper and boron-polyethylene are 38 cm and 14 cm and the boron concentration is 1.00%.
An Electromagnetic Protection Design Evaluation Algorithm for Complex Electronic Systems Based on Margin Estimation
Authors: Tao Lingjiao , Fan Jieqing , Guo Chunying , Wen Yongzhi , Liu Zhiyong 
Published: January 2021

Abstract
Based on the analysis of random error sources in the design margin evaluation of electromagnetic protection for complex electronic, it is researched on a method of evaluating electromagnetic pulse protection capability, the total error standard deviation evaluation theory is analysed. A new method for evaluating the electromagnetic pulse protection capability of complex electronic systems based on the lower limit estimation of design margin and corresponding reliability and confidence is proposed. So taking the evaluation of electromagnetic protection design interval of a certain type of electronic information system as an example, the application and the qualification conditions of the algorithm are illustrated.
Influence of Mesoscale Vortex on Underwater Low-Frequency Sound Propagation
Authors: Xiao Rui , Lei Fuqiang , Zhu Hanhao , Chen Chao , Xue Yangyang 
Published: January 2021

Abstract
To discuss the effect of an ocean mesoscale vortex on underwater low-frequency sound propagation, a theoretical model of a sound field under the action of an ocean mesoscale vortex was established based on acoustic wave theory and ray theory, using the finite element method. The influences of vortex properties and vortex intensity on the characteristics of sound propagation are discussed. The simulation results indicate that, in a cold vortex, the acoustic convergence zone moves toward the sound source, the span of the convergence zone decreases, and the convergence gain increases. Alternatively, for a warm vortex, the convergence zone moves away from the sound source, the span of the convergence zone increases, the sound rays diffuse, and the convergence gain decreases; the greater the vortex intensity, the greater is the effect on the motion and gain of the convergence region.
Discovery of Four Space Dimensions in a Sphere for Electronic Orbitals in a Neon Shell
Authors: Xu Kunming 
Published: January 2021

Abstract
For the first time we discover four space dimensions in a sphere, namely two periphery points, two semicircular arcs, two hemispherical surfaces, and two spherical solids. When these four geometric elements are compared with electronic orbitals in a neon shell, we draw a conclusion that while 2s orbitals are spherical, three types of 2p orbitals in the X, Y, and Z directions are different in the number of space dimensions. These anisotropic 2p orbitals prompt us to modify Schrödinger’s equation to reflect these fine space gradients. Within the atomic sphere, electrons are transforming from one dimension to another following the rule of calculus implemented by circular functions rather than position movement. An electron may exist in the physical shape of a point, an arc, a surface, or a solid. Eight electrons in the neon shell are undergoing various harmonic oscillations that form a continuous octet cycle. This motion feature is derived from a four-dimensional space harmonic oscillation equation coupled with a one-dimensional time harmonic oscillation equation in synthesis of the modified Schrödinger’s equation. Substantial amount of evidence can be found in organic chemistry where a carbon atom has an anisotropic electron configuration of 2s2px2py2pz. By furnishing a fresh and fundamental spacetime worldview, the quaternity theory may change the direction of quantum mechanics from discrete linear algebra toward continuous dynamic calculus in the future.
The Kinematic Modeling and Simulation of an Adjustable Pivot Point of Six Degree-of-Freedom (DOF) Parallel Robot
Authors: Tan Shuang , Liang Fengchao , Chen Long , Lin Zhe 
Published: January 2021

Abstract
For the pose requirements of secondary mirror in the large aperture space optical remote sensor, the pose adjustment is applied to the pivot point of secondary mirror. So the adjustable pivot point kinematic model must be set up. Based on the characteristics of the pivot point fixed with the moving platform, the corresponding coordinate system is built, and the adjustable pivot point kinematic model is established on the Euler rotation. Then virtual prototype model and the pivot point are built in ADAMS, and the kinematic simulation method is given. Finally, a 6-DOF parallel robot as secondary mirror pose adjustment device of an optical remote sensing system is taken as an example, and the adjustable pivot point kinematic model and ADAMS simulation method are carried out. The results show that the model and simulation method are correct and practical, which can be used in any field of a 6 DOF parallel robot with adjustable pivot point.