bluuebunny/crossref_metadata_2025_split huggingface dataset:
Association between Patellofemoral Anatomy and Chondral Lesions of the Knee in Patellofemoral Instability
Authors: O'Malley Olivia , Choudhury Aliya , Biggs Alexandra , Humdani Alina J. , Brown Oliver , Smith Toby O. , Ejindu Vivian , Hing Caroline B. 
Published: June 2021

AbstractChondral injury is a serious consequence of patellar dislocation and patellofemoral instability (PFI). There is limited data on the relationship between radiological features such as sulcus angle and patellar height to the presence, location, and severity of chondral lesions. The purpose of this study was to determine the association of anatomical variants in patellofemoral instability with injuries sustained due to patellar dislocation. A cohort of 101 patients who had four or more episodes of dislocation or instability undergoing isolated arthroscopy or arthroscopies at the time of corrective realignment surgery were identified. The prevalence of chondral, ligamentous, and meniscal injuries was determined and correlated to the sulcus angle, tibial tubercle trochlear groove distance, and patellar height on magnetic resonance imaging (MRI) scans. A total of 101 patients was identified. At arthroscopy, the patella demonstrated the highest incidence of chondral injury (68%) followed by the trochlear groove (40%). Lateral meniscal injuries were noted in 6% of patients, medial meniscal injuries in 2%, and anterior cruciate ligament (ACL) injury in 3%. Chondral injuries were graded using the Outerbridge criteria and there was a correlation between more severe chondral injuries and a greater tilt angle (p = 0.05). The occurrence of injury to the lateral meniscus was associated with a higher Insall–Salvati ratio (p = 0.05). More severe chondral injuries are seen in patients with a greater tilt angle.
Distal Femoral Replacement for Fractures Allows for Early Mobilization with Low Complication Rates: A Multicenter Review
Authors: Stancil Ryan , Romm Jacob , Lack William , Bohnenkamp Frank , Sems Stephen , Cross William , Cass Joseph , Keeney James , Nam Denis , Nunley Ryan , Fernando Navin , Sassoon Adam 
Published: June 2021

AbstractPeriprosthetic fractures around a total knee arthroplasty (TKA), comminuted and intra-articular femur fractures, or fracture nonunions in osteoporotic bone represent technically challenging problems. This is particularly true when the fracture involves a loose femoral component or the pattern results in suboptimal fixation potential. These clinical indications often arise in an older and comorbid patient population in whom a principal goal of treatment includes allowing for early mobilization. Limited data indicate that arthroplasty via distal femoral replacement (DFR) is a reasonable alternative to open reduction and internal fixation, allowing for early ambulation with low complication rates. We performed a retrospective review of trauma and arthroplasty surgeries at three tertiary referral institutions. Adult patients treated for the above with a DFR were included. Patients with active infection, open and/or high-energy injuries and revisions unrelated to fracture were excluded. Patient demographics, treatment details, and outcomes were assessed. Between 2002 and 2017, 90 DFR's were performed for the above indications with a mean follow-up of 24 months. Postoperatively, 80 patients (88%) were allowed to weight bear as tolerated, and at final follow-up, 9 patients (10%) remained dependent on a wheelchair. The average arc of motion at final follow-up was 95 degrees. There were seven (8%) implant-related complications requiring secondary surgeries: two infections, one with associated component loosening; one fracture of the hinge mechanism and one femoral component failure in conjunction with a patellofemoral dislocation (both requiring revision); one case of patellofemoral arthrosis in a patient with an unresurfaced patella; one periprosthetic fracture with associated wound dehiscence; and one case of arthrofibrosis. In each of these cases, only modular components of the DFR were exchanged. All nonmodular components cemented into the femur or tibia were retained. DFR provides a viable reconstruction option in the treatment of acute distal femur fractures, periprosthetic femur fractures, and fracture nonunions. We noted that in an elderly patient population with high comorbidities, the complication and secondary surgery rates remained relatively low, while allowing for immediate weight bearing.
Repair of a Divergent Elbow Dislocation with Distal Ulnar Fracture in a Dog Using TightRope and External Skeletal Fixation
Authors: Garcia Marcos , Bismuth Camille , Deroy-Bordenave Claire 
Published: June 2021

AbstractThe aim of this study was to report the outcome in a 6-year-old male English Setter dog that suffered a combination of divergent elbow dislocation and open distal ulnar fracture. This study is a case report. After surgical reduction in the elbow luxation, the dog was treated with the TightRope fixation system used as replacement of the lateral collateral ligament, a radioulnar positional screw, and external skeletal fixation. Removal of all implants was performed 3 months postoperatively. The 6-month follow-up visit found the dog without lameness, displaying normal activity, and with normal elbow range of motion and normal Campbell's test. Successful surgical management was achieved with good long-term results using TightRope, a positional screw, and an external skeletal fixator.
Piracy in the Gulf of Guinea: a threat to the means of livelihood of artisanal fishers in South South region, Nigeria
Authors: Asua Samuel A. , Ugwueze Michael I. , Onah Vincent C. 
Published: June 2021

SUMMARY
The rising spate of piracy in the Gulf of Guinea, targeting artisanal fishery, is a huge concern regarding security and economy. Relying to a major extent on qualitative primary data, this briefing explores the economic effects of piracy by providing empirical evidence of how the piracy attacks in the Gulf of Guinea contribute to the increasing food security crisis among the coastline population in the South South region, Nigeria. It argues that the increasing piracy on artisanal fishery is a manifest sign of state fragility in the country.
Concentric double hollow grid cathode discharges. Spectral investigations and phenomenological approach
Authors: Konrad-Soare C T , Enescu F , Dimitriu D G , Dobromir M , Teodorescu-Soare E G , Mazzanti F , Irimiciuc S A , Ionita C , Schrittwieser R 
Published: June 2021

Abstract
A discharge plasma is created by simultaneously biasing two concentric spherical grids with axisymmetric orifices. In this geometry, space charge structures in the form of multiple quasi-spherical luminous plasma bodies appear simultaneously inside and around the cathodes. The plasma formations are highly interdependent supplying each other with the particle flow and current closure necessary for the maintenance of the discharge. To diagnose these structures, space-resolved cold Langmuir probe measurements and optical emission spectroscopy investigations were performed in the axial direction allowing for the mapping of the axial profiles of plasma potential, electron temperature and density, ion density and optical emission. The existence of an accelerating double layer in the vicinity of the holes has been confirmed here, and in previous research (Teodorescu-Soare C T et al 2016 Phys. Scr.
91 034002; Schrittwieser R W et al 2017 Phys. Scr.
92 044001; Teodorescu-Soare C T et al 2019 Int. J. Mass Spectrom.
436 83). Besides the assessment of the relationship between discharge conditions and plasma parameters in the novel cathode system, the importance of a multiple concentric cathode discharge configuration is revealed for deposition applications.
Gravitational Leptogenesis in Bounce Cosmology
Authors: Barrie Neil D. 
Published: June 2021

Abstract
We investigate whether successful Gravitational Leptogenesis can take place during an Ekpyrotic contraction phase. Two possible paths by which this can occur are coupling the Ekpyrotic scalar to a gravitational Chern-Simons term, or to a U(1) gauge field Chern-Simons term. These couplings lead to the production of chiral gravitational waves, which generate a lepton number asymmetry through the gravitational-lepton number anomaly. This lepton asymmetry is subsequently reprocessed by equilibrium sphaleron processes to produce a baryon asymmetry. We find successful Gravitational Leptogenesis to be possible in Ekpyrotic bounce cosmologies through both of these mechanisms.
Droplet Deformation under Conditions of Neutral Buoyancy
Authors: Denisova M O , Kostarev K G 
Published: June 2021

Abstract
One of the classical problems of hydrodynamics is the problem of droplet deformation in the state of neutral buoyancy under the action of an external force. It is assumed that if the droplet size is initially equal to or less than the capillary diameter, it takes the shape of a regular sphere, regardless of the density gradient in the environment and the droplet, the degree of their mutual solubility, the possibility of Marangoni convection, and the time elapsed since the creation of the system of liquids. To elucidate the influence of these unaccounted factors as well as that of initial deformation of the droplet, we experimentally studied the evolution of the shape of large-diameter droplets in the solution with density stratification. The droplet behaviour was studied in the case when it took the form of a spheroid flattened vertically under the action of gravity. The interferometer was used to visualize the distribution of solution concentration near the drop. The dependence of the ratio of the vertical to horizontal diameter of the droplet on time and the average concentration gradient in the surrounding medium was determined.
Study of Viscoelastic Properties of Fluids for Hydraulic Fracturing
Authors: Efremov D V , Bannikova I A , Bayandin Yu V , Krutihin E V , Zhuravlev V A 
Published: June 2021

Abstract
The study focuses on the rheological behavior of a fluid based on a viscoelastic surfactant (Surfogel grade D, type 70-100, produced by JSC “Polyex”) in wide range of strain rates. This fluid is used for hydraulic fracturing technology as a proppant-carrying and proppant-retaining fluid in order to enhance oil recovery, including those with hard-to-recover oil and gas reserves. Quasi-static experiments to determine the values of the dynamic viscosity of the fluids under study were carried out using a falling ball viscometer (according to the Stokes method). The viscoelastic properties of fluids were studied using a Physica MCR501 rheometer with a cone-plane measuring system and an original rheometer with coaxial cylinders measuring system. The rheological properties of the fluid with the addition of proppant were studied using a Rheolab QS rheometer with a measuring system of the type of coaxial cylinders. The analysis of the rheological properties of fluids based on a viscoelastic surfactant has been carried out, and it has been established that fluids based on a viscoelastic surfactant has stable rheological properties over the entire range of strain rates, including fluid with proppant concentration up to 20%.
Study of the Influence of the Time of Mechanical Processing of Powder Mixture of Composition Ti – 25 wt. % TiN in a Planetary Mill on the Characteristics of Composite Particles
Authors: Drozdov V O , Chesnokov A E , Cherepanov A N , Smirnov A V 
Published: June 2021

Abstract
In this work, by the method of mechanical processing in a high-energy planetary mill of titanium powder (PTS – 1) and ceramic powder of titanium nitride, composite particles with a size of 10 to 100 μm were obtained, in the volume of which ultrafine particles of titanium nitride are distributed. It is assumed that the use of such particles in powder spraying by cold or thermal spray will increase the homogeneity of the distribution of refractory elements in the coating volume. Depending on the time of mechanical treatment of the powder mixture containing three weight fractions of ultrafine particles of titanium nitride, agglomerated composite particles were obtained. Their granulometric composition and surface morphology were studied; a map of the distribution of elements over the surface and volume of the particle material is obtained. It is noted that during mechanical processing of materials in a planetary mill, the behavior of titanium nitride particles is similar to the role of a surfactant. It is shown that the time of mechanical processing of the powder mixture for three minutes is optimal: composite particles have an average size of 38 microns; mass fraction of particles of fraction 20 – 90 μm more than 60 %.
Computer Simulation of Elastomeric Blade and Annular Specimens Testing Taking into Account the Deformation Rate of Their Working Parts
Authors: Garishin Oleg K , Pelevin Alexander G , Sokolov Alexander K 
Published: June 2021

Abstract
Computer simulation of blade and annular samples made of polymer viscoelastic materials testing has been carried out. Calculations have shown that the rate of material deformation in the working part of the blade specimen can differ significantly from that calculated by the movement of tensile testing machine grips. This is due to the unevenness of the cross-section of blade sample: in the middle (working part) it is constant, and at the ends its area increases. As a result, inhomogeneous stress fields arise in the material, which leads to a variable deformation rate of the specimen working part, even in case when grips move at a constant speed. This effect is not significant at small deformations and a low strain rate and can be ignored in principle. However, in the case of large extensions high speeds, it can seriously distort the test results. According to the authors, the way out of this situation is that, in experiments with viscoelastic polymers, it is better to use annular specimens with the same cross-section along the entire length, rather than blade ones. As shown by computer calculations, in this case, this problem almost completely ceases to exist.
Approaches to Calculating Loads on Interchamber Pillars under Incomplete Undermined Conditions
Authors: Glebova P A 
Published: June 2021

Abstract
The paper uses mathematical modeling to calculate loads on interchamber pillars under incomplete undermined conditions by using the room and pillar system at great depths and by retaining rigid barrier pillars. The approaches are based on the method of the fictitious pillars, as well as the method of forming a rock pressure arch in the incompletely undermined area. The unloading effect of the barrier pillars on the interchamber pillars is shown, the distribution of vertical loads is obtained, and the height of the rock pressure arch is calculated.
Semicontact AFM Mode for Fast Determining the Subsurface Structure of Filled Elastomers
Authors: Izyumov R I , Kislitsyn V D , Svistkov A L 
Published: June 2021

Abstract
Using atomic force microscopy in the semicontact AFM mode, we examined the surface of the filled elastomer obtained by the rupture method. A feature of the material is that it consists of a soft binder and hard nanofiller particles. Filler particles are usually hidden by a binder layer. In our work, we have shown that the information on the phase shift obtained during scanning makes it possible to look into the subsurface layer and obtain more information about the geometry of the filler particles and their location in the nanocomposite. It is possible to make visible the fragments of particles immersed in the binder, which are almost invisible on the surface relief. This does not require the use of special modes of the atomic force microscope for analysis. It is enough to use the reliable and fast scanning method in semicontact mode.
Waves on a Free Surface of Ferrofluid Layer, Laying on a Liquid Substrate
Authors: Khokhryakova C A , Kolesnichenko E V 
Published: June 2021

Abstract
Waves on the free surface of a magnetic fluid located on a liquid substrate were studied experimentally. The wave motion of the surface was induced by a homogeneous oscillating magnetic field orthogonal to the layer. In this case two types of waves can be formed on the surface of a magnetic fluid: a standing wave of the same frequency as the alternating magnetic field, and a standing wave, independent of the field frequency. The paper reviews the main theoretical and experimental studies of wave instability of such systems. The stability of a two-layered liquid system in an alternating vertical magnetic field is investigated. For efficient processing of the experimental results, the optical part of the experimental setup was modified. An algorithm has been developed for processing the profiles of the magnetic fluid surface obtained during the experiment, which helps to determine the length of the generated waves.
Study of the Convective Stratification of Airflows in a Mine Shaft
Authors: Kolesov E V , Kazakov B P , Grishin E L 
Published: June 2021

Abstract
The experimental study of heat and mass transfer in the atmosphere of a skip shaft of a Gypsum mine was carried out during the summer and winter seasons. The air flow overturning was observed in the winter season due to the ingress of cold heavy air from the surface into the shaft space. To analyze this phenomenon, a computational fluid dynamics (CFD) model of heat and mass transfer processes in a mine shaft was developed, considering the vertical temperature gradient, roughness of the shaft walls, heat exchange with the shaft lining. Based on numerical simulation, it was found that at relatively low air velocities in the shaft and with a relatively large difference between warm air in the shaft and cold air on the surface, the latter begins to penetrate the shaft and descend down it, gradually filling its space. The interaction of cold air from the surface with the warm air rising up the shaft, as well as with warm walls of the shaft leads to the formation of an unsteady convective vortex cellular structure along the shaft. The depth of the vortex depends on the velocity of the air in the shaft, as well as the difference between the temperatures of the warm and cold air. Based on the obtained numerical simulation data, it was possible to calculate the minimum allowable air velocity at which partial return air flows appear in the shaft cross-section.
Stationary Thermomagnetic Convection of Ferrofluid in an Enclosed Loop
Authors: Koskov M A , Pshenichnikov A F 
Published: June 2021

Abstract
This paper presents an experimental study of thermal convection of ferrofluid inside a closed hydrodynamic loop heated from the side in the presence of a magnetic field applied to the loop section nearby the heater. The pipes of the circuit are blown with a stream of thermostatic air, which ensures a constant heat transfer coefficient on the outer surface of the pipes and an exponential temperature distribution along the circuit. The value of the exponent measured provide information on the integral axial heat flux (Nusselt number). The experiments were conducted with undecane under natural gravitational convection and with a colloidal solution of magnetite in kerosene of moderate concentration under mixed (gravitational and thermomagnetic) convection at the Rayleigh numbers varied in the range 103 – 104. It is shown that thermomagnetic convection causes a 4 – 6 – fold increase in heat transfer.
New Experimental Results on Steady Streaming in Oscillating Deformable Spherical Container
Authors: Kozlov N V 
Published: June 2021

Abstract
The paper presents an experimental study of steady streaming generated by harmonic oscillations of the boundaries of a deformable spherical container. The container is filled with a viscous fluid and its oscillations are produced by means of two linear servo motors, installed symmetrically. The shape of the boundary during deformation is studied by processing images recorded with a high speed camera. The flows are investigated using the particle image velocimetry. In the analysis of results, the focus is made on the relation between the shape of the oscillating boundary, the dimensionless frequency and the streaming velocity. The possibility of controlling the steady streaming pattern in order to affect the convective mass transfer is discussed.
Mathematical Modeling of Invasive Carcinoma: Biomechanics of Small Groups of Cancer Cells
Authors: Krasnyakov I V , Bratsun D A , Pismen L M 
Published: June 2021

AbstractAccording to the latest research, cancer is a complex biological system that evolves over time and space. This means that cancer cells differ from each other in their functions in the tumor. They engage in various interactions with the microenvironment and compete for available nutrients to survive. The main problem of mathematical modeling in oncology today is the heterogeneity of a typical malignant neoplasm. In this work, we propose a chemomechanical model of the pattern formation of small groups of cancer cells of invasive carcinoma of a non-special type (IC NST). The model assumes that carcinoma is a heterogeneous formation, which consists of cells of different phenotypes performing different tasks to maintain the existence of the tumor. In the model, each cell is represented as a deformable polygon that changes its shape and size as the tissue develops. Numerical modeling implements various subtypes of IC NST structures. These patterns are compared with morphological structures identified in clinical studies.
Dynamics of Flat Barium Hexaferrite Particles in a Lyotropic Liquid Crystal
Authors: Lebedev A V , Lysenko S N 
Published: June 2021

Abstract
This paper describes the results of experiments on the magnetization of barium hexaferrite particles embedded in lyotropic liquid crystals. The carrier liquid crystal medium was an aqueous solution of a mixture of sodium lauryl sulfate and lauric acid in a ratio 2/1. Barium hexaferrite particles were stabilized with two layers of surfactant. The first layer consisted of oleic acid molecules. Second layer was a mix of sodium lauryl sulfate and lauric acid in a ratio 1/1. The process of particle magnetization was investigated by observing the effect of birefringence. The intensity of light passing through the system of crossed polaroids and the time of its establishment were measured depending on the magnitude of the magnetic field and the concentration of the components of the liquid crystal. It was found that the field dependence of the birefringence effect changes significantly depending on the concentration of the liquid crystal. In a concentrated solution in the liquid-crystalline phase, a significant enhancement of the birefringence effect is observed in weak fields. As the concentration of the solution decreases, the field dependence of the birefringence effect smoothly transforms into the curve for particles dispersed in water.
Behaviour of a Ternary Mixture with the Net Separation Ratio Close to Zero
Authors: Lyubimova Tatyana , Prokopev Sergei , Shevtsova Valentina 
Published: June 2021

Abstract
The behaviour of the ternary hydrocarbon mixture of toluene-methanol-cyclohexane in mass proportion 0.62/0.31/0.07 is studied. The direct numerical simulation is carried out for the two-dimensional closed cavity heated from above. The mixture is supposed to be in the gravity field. The behavior of the mixture is predominantly caused by the Soret effect (thermal diffusion). An important parameter, responsible for the Soret effect, is the net separation ratio, Ψ. For the mixture under consideration, the two sets of values of Ψ are known. In both cases, the values of Ψ turn out to be close to zero, but in one case Ψ is slightly positive, and it is slightly negative in the second one. This results in qualitative difference in the evolution of the mixture under consideration. If Ψ > 0, the mixture comes to the mechanical equilibrium. If Ψ < 0, we observe the system to be at the border of stability, under small perturbation there is no instability, but for the perturbation amplitude higher than a threshold value of the convective single-vortex flow arises.