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[Display omitted] Hypothesis: In the interfacial wetting boundary, the superhydrophobic surface is often damaged, and the anisotropic wettability of its surface has attracted many researchers' attention. The "petal effect" surface has typical anisotropic wettability. We predict that under the dual conditions of structural defects and high impact velocity, the "petal effect" becomes more adhesive on the surface. Experiments: This study refers to the droplet state on rose petals, structural defects were constructed on the superhydrophobic surface. This paper studies the influence of macro-structural defects on the wettability change from natural to bionic "lotus effect" to "petal effect" in both static and dynamic angles. Findings: Macro defects significantly change the static contact angle of the superhydrophobic surface. The higher the impact velocity of the droplet, the higher the energy dissipation of the "petal effect" surface (DSHS), which improves the adhesion of the surface to the droplet and prolongs the contact time. It is found that the defect structure and high impact velocity will directly affect the deposition and desorption of droplets on the superhydrophobic surface, and they are both essential. This wetting dynamic law is very likely to be helpful in the quantitative design of defect structure scale for dynamic desorption of droplets on superhydrophobic surfaces. [ABSTRACT FROM AUTHOR]

Starting from the Bogolubov–de Gennes equations for superconductor with an arbitrary anisotropic Fermi surface we derive the Andreev-type theory accounting for the quasiparticle trajectory interference and corresponding nonquasiclassical quantization effects. The resulting Andreev equations are applied for the analysis of the subgap quasiparticle states localized at the pinned vortex cores. The normal reflection of electrons and holes at the defects is shown to result in the qualitative transformation of the subgap spectra and formation of new types of bound quasiparticle states. We focus on the effect of the Fermi surface anisotropy on the quasiparticle spectral properties including opening of soft and hard minigaps in the spectrum and spatial behavior of the local density of states around pinned vortex cores. [ABSTRACT FROM AUTHOR]

Purpose: Fractures occurring at the metaphyseal–diaphyseal junction of the distal humerus in children are not commonly documented in the literature. Until this moment, there is no gold standard technique regarding its management and most surgeons treat it as a regular supracondylar humerus fracture by conventional pinning. This systematic review explores the relevant literature to assess the efficacy of different techniques. Methods: This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Our literature search encompassed several online databases, including PUBMED/MEDLINE, Scopus, Web of Science Core Collection, and Google Scholar. Data from articles that met our general inclusion criteria were extracted and categorized into treatment method groupings. Functional and cosmetic outcomes, demographic characteristics, and complications were the main parameters used to analyze the data. Results: Ten retrospective studies met our inclusion criteria with a total of 178 participants of unilateral pediatric distal humerus metaphyseal–diaphyseal junction fractures. Most literature chose closed reduction and percutaneous pinning in seven articles, followed by elastic stable intramedullary nail technique used in three articles, then conservative treatment was chosen in two articles, while only one article used lateral miniplate and assisted K-wire and another article used combined closed reduction and percutaneous pinning and intramedullary K-wire. As regards the operation time; elastic stable intramedullary nails had the shortest time with a mean of 39.7 min (range: 37.5–41.9 min), while closed reduction and percutaneous pinning had the longest time with a mean of 75.47 min (range: 55.9–92.1 min). The shortest healing time was observed in miniplate with a mean of 7.2 weeks, while the most prolonged was in conservative management with a mean of 12 weeks and closed reduction and percutaneous pinning was a mean of 10 weeks. Regarding Flynn's criteria, all participants received excellent and good except in closed reduction and percutaneous pinning; 13 cases were fair and 2 cases were poor. Regarding complications, the most commonly observed complication after metaphyseal–diaphyseal junction fracture was cubitus varus, the highest incidence was in conservative management (33% of cases), followed by closed reduction and percutaneous pinning (10.9% of cases), the least incidence was observed in elastic stable intramedullary nails (3.77% of cases), and none of the cases treated with mini plate developed this complication. Other complications were observed only with closed reduction and percutaneous pinning; 8.5% of cases developed fixation loss, 6.2% of cases had a significantly reduced range of motion, and one case refractured. Conclusion: Pediatric distal humerus metaphyseal–diaphyseal junction fractures should be distinguished from the more prevalent supracondylar humerus fractures, as conventional pinning techniques are associated with a higher incidence of complications and increased both operative and healing times. Level of evidence: III [ABSTRACT FROM AUTHOR]

Background: Injuries to the metacarpal bones are widespread and may severely limit a person's ability to go about their everyday lives. Unstable fractures usually need surgical intervention. Objectives: This study aimed to investigate how well Kirschner wires percutaneous fixing improves the prognosis of patients with unstable metacarpal fractures. Patients and methods: Fifteen patients with unstable metacarpal fractures were included in this study. They were treated by percutaneous fixation at Sharm El Sheikh Hospital through the period from 2017 to 2019. Nine patients in group 1 had antegrade intramedullary bouquet fixation and six in group 2 had transverse pinning. The results were evaluated using the total active movements (TAM) score after clinical and radiological follow-ups. Results: The mean patient age was 33.26 years. There were no statistically significant differences between the groups when it came to the intervals of time before fixation (p=0.64) and time until union (p=0.44). Results showed that both group 1 (76.77%) and group 2 (66.66%) when evaluated using TAM scores (p=0.26), had very good results. There were also no statistically significant differences between both groups in terms of the duration of follow-up or surgical complications (p=0.39 and p=0.35 respectively). Conclusion: There were no major variations in clinical or radiological outcomes between intramedullary and transverse pinning approaches when it comes to percutaneous fixation with Kirschner wires for unstable metacarpal fractures. Both methods provided equivalent results. [ABSTRACT FROM AUTHOR]

Introduction: Metacarpal fractures account for 25%-50% of all hand fractures and may negatively impact hand function and ability to work. Percutaneous transverse pinning of non-articular metacarpal fractures allows mobilisation immediately after the procedure. Methods: Between March 2017 and February 2022, 56 patients undergoing percutaneous transverse pinning for unstable metacarpal fractures were prospectively recruited. We investigated surgical outcomes in terms of Patient-rated Wrist/Hand Evaluation (PRWHE) and pre-and post-operative radiographic evaluation. The Student t-test was used to compare the means of PRWHE values after surgery. Statistical significance was set at p < 0.05. Results: The mean age was 40.21 ± 17.9 years (range of 16 to 86 years). The average operating time was 27.96 min. The mean follow-up period was 14.3 ± 6.4 months (from 2 to 41 months). The mean PRWHE score was 6.5 ± 1.8. None of the patients had clinically observable rotational deformities, and the functional outcomes were satisfactory. Conclusion: Percutaneous transverse pinning for non-articular metacarpal fractures restores excellent function, and imaging results are satisfactory. Further high-quality clinical trials are required to validate these results on a larger scale. Level of evidence: II, prospective cohort study. [ABSTRACT FROM AUTHOR]

Purpose: With this prospective randomized control trial (RCT), we aim to provide the outcome analyses of the three most used treatment modalities for distal end of radius (DER) fracture management in the elderly. Methods: A prospective randomized control trial was performed. Fifty-two patients with DER fractures (AO A2, A3, C1, or C2) were randomized to the casting (n = 17), percutaneous pinning (n = 18), and the volar plating group (n = 17). Radiological measurements measured were radial inclination (RI), radial height (RH), volar tilt (VT), and ulnar variance (UV). The outcome was measured based on range-of-motion, grip strength, Patient-Related-Wrist-Evaluation (PRWE) score, and the Quick-Disabilities-of-the-Arm-Shoulder-Hand (QDASH) score. Results: Immediate post-operative and 1-year-follow-up X-rays showed a significant difference measurement between the groups (p < 0.05). Pairwise comparisons of the casting and pinning groups (p < 0.05) and the casting and plating groups (p < 0.05) revealed significant differences at the 1-year follow-up, but not the pinning and plating groups (p > 0.05). The analysis found significant differences in clinical outcomes after 1 month of follow-up, with the plating group outperforming the other two (p > 0.05). However, after a year of follow-up, all groups had comparable outcomes; however, the plating group showed improved palmar flexion (p < 0.001), radial deviation (p < 0.001), and a lower PRWE score (p < 0.05), indicating better wrist function. Complications were more in casting group. Conclusion: The study found a radiologically significant difference between groups throughout the follow-up, but it did not affect functional results. Clinical outcomes were similar across the groups, with plating showing better palmar flexion and radial deviation. Grip strength was also better in the plating group, but statistically insignificant. The study suggests plating should be chosen over other treatments for high-demand patients. [ABSTRACT FROM AUTHOR]

The intensive development of hydrogen technologies has made very promising applications of one of the cheapest and easily produced bulk MgB2-based superconductors. These materials are capable of operating effectively at liquid hydrogen temperatures (around 20 K) and are used as elements in various devices, such as magnets, magnetic bearings, fault current limiters, electrical motors, and generators. These applications require mechanically and chemically stable materials with high superconducting characteristics. This review considers the results of superconducting and structural property studies of MgB2-based bulk materials prepared under different pressure–temperature conditions using different promising methods: hot pressing (30 MPa), spark plasma sintering (16–96 MPa), and high quasi-hydrostatic pressures (2 GPa). Much attention has been paid to the study of the correlation between the manufacturing pressure–temperature conditions and superconducting characteristics. The influence of the amount and distribution of oxygen impurity and an excess of boron on superconducting characteristics is analyzed. The dependence of superconducting characteristics on the various additions and changes in material structure caused by these additions are discussed. It is shown that different production conditions and additions improve the superconducting MgB2 bulk properties for various ranges of temperature and magnetic fields, and the optimal technology may be selected according to the application requirements. We briefly discuss the possible applications of MgB2 superconductors in devices, such as fault current limiters and electric machines. [ABSTRACT FROM AUTHOR]

We present a numerical study, using the vortex filament model, of vortex tangles in a flow of pure superfluid 4 He in the T = 0 limit through a channel of width D = 1 mm for various applied velocities V. The flat channel walls are assumed to be microscopically rough such that vortices terminating at the walls are permanently pinned; vortices are liberated from their pinned ends exclusively through self-reconnection with their images. Sustained tangles were observed, for a period of 80 s, above the critical velocity V c ∼ 0.20 cm s - 1 = 20 κ D . The coarse-grained velocity profile was akin to a classical parabolic profile of the laminar Poiseuille flow, albeit with a nonzero slip velocity ∼ 0.20 cm s - 1 at the walls. The friction force was found to be proportional to the applied velocity. The effective kinematic viscosity was ν ′ ∼ 0.1 κ , and effective Reynolds numbers within Re ′ < 200 . The fraction of the polarised vortex length varied between zero in the middle of the channel and ∼ 60% within the shear flow regions ∼ D / 4 from the walls. Therefore, we studied a state of statically polarised ultraquantum (Vinen) turbulence fuelled at short length scales by vortex reconnections, including those with vortex images due to the relative motion between the vortex tangle and the pinning rough surface. [ABSTRACT FROM AUTHOR]

Sm-Fe-N material holds immense promise as new material for developing next generation permanent magnets. However, the achievement of high coercivity in this material remains a big challenge, and moreover new coercivity theories beyond the commonly considered nucleation-type mechanism needs exploration. This study describes both the yielding of anisotropic Sm-Fe-N powders with high coercivities and the discovery of new coercivity mechanism by a systematic study using a designed milling preparation method. As a result, a random-direction cleavage behavior with unexpected XRD peak shifts and formation of new micron-sized flower-like particles were found in the yielded Sm-Fe-N powders. The grain sizes of the powders are of nanoscale dimension and they refine gradually as the milling time increases. The measured coercivity is up to 15.0 kOe, which is a substantial increase of approximately 36.4% compared to the original commercial powders and among the highest reported values via the milling preparation method (commonly below 13 kOe). The yielded powders also demonstrate a new dual-type coercivity mechanism (combing both nucleation-type and pinning-type control effect), and the improved pining effect contributes to the high coercivities. This study opens the door of utilizing pinning effect for achieving high coercivities in anisotropic Sm-Fe-N material.

Background. Distal radius fracture has been reported as the most common type of extremity fractures in adults. No treatment method has been introduced definitely for this type of fracture, especially for maintaining hand function in the best state. The aim of this study — to assess the functional and radiological outcomes following three surgical methods, including external fixation, K-wire and external fixation with pinning. Methods. This parallel-designed randomized controlled trial was conducted on adult patients with intra-articular fracture of distal radius. The participants were allocated in three research groups with block random sampling, and were matched for their age and gender. Primary outcome was radiographic parameters, including radial inclination, radial height, ulnar variance and dorsal/palmar tilt. Secondary outcome was the patient’s performance examined with DASH and PRWE questionnaires. All participants were followed 6, 12 and 24 weeks after the surgery for evaluation of these outcomes. Results. Totally, 78 patients, including 42 male and 36 female with mean age of 46.94±11.05 years completed the research protocol. Although the four radiologic primary endpoints were in the normal clinical range after the intervention, a significant statistical difference was observed between the three groups (р0.001). Also, both DASH and PRWE score showed a significant decrease after the therapeutic interventions (р0.001). Conclusion. The statistically significant difference in the research outcomes of the external fixation with pinning can show that this treatment method theoretically preserves the anatomical condition better than the other two methods, and probably has better functional effects on short-term and intermediate-term results following the surgery.

Calcaneus fractures Sanders type II have been historically treated with various modalities. However, few studies compared these procedures directly. The multicenter (TRON group) retrospective study compared the radiographic and clinical outcomes of operative procedures using Kirschner wires (K-wires), cannulated cancellous screws (CCSs) and plates. Between 2014 and 2020, 121 patients with Sanders type II calcaneus fractures were surgically treated in our group using K-wire (Group K: n = 31), CCS (Group C: n = 60) or plate (Group p: n = 30) fixation. We assessed the American Orthopedic Foot and Ankle Society (AOFAS) score and infection after operation as clinical outcomes and Böhler's and Preiss' angles as radiographic outcomes. The AOFAS scores of the 3 groups showed a significant difference, with Group P showing significantly inferior scores to Group C at 6 months postoperatively and at the final follow-up examination (p =.015 and p <.001, respectively). The rate of infection did not differ to a statistically significant extent, but the incidence in Group P tended to be higher in comparison to the other groups. Among the three groups, Böhler's angle did not differ to a statistically significant extent immediately after the operation (p =.113) or at the final follow-up examination (p =.383). Postoperatively, Preiss' angle did not differ to a statistically significant extent (p =.251) but was significantly smaller in the Group C at the final follow-up examination (p =.0331). In Sanders type II calcaneus fracture, CCS fixation may obtain the best functional outcomes. [ABSTRACT FROM AUTHOR]

Hammertoe deformity is a common forefoot pathology, characterized by a progressive deformity with dorsiflexion of the proximal phalanx on the metatarsal head at the metatarsal phalangeal joint (MTPJ) and plantarflexion of the intermediate phalanx on the proximal phalanx at the proximal interphalangeal joint (PIPJ). While there is literature available discussing open techniques for hammertoe correction, there is a lack of publications discussing minimally invasive techniques, therefore the objective of this retrospective comparative study is to evaluate minimally invasive versus open hammertoe surgery in terms of time to osseous union, complications, recurrence, and return to full activity. Sixty eight feet among 41 patients met the inclusion criteria and were surveyed. Among the 68 feet, 54 feet (124 toes) underwent minimally invasive hammertoe correction and 14 feet (22 toes) underwent open hammertoe correction. Time to osseous union (weeks) in the MIS group was 8.76 ± 2.31 weeks with similar outcomes to the open group with union at 8.42 ± 2.31 (p =.65). Return to activity (weeks) was 10.47 ± 3.45 in the MIS group and 9.92 ± 3.03 in the open group with no statistical significance (p =.62). There was 4 recurrent hammertoe deformities in the MIS group (3.23%) with no recurrent hammertoes in the open group (0%). In the MIS group 5 hammertoes had unplanned hardware removal (4.03%) compared to 0 in the open group. There was no statistical significance for both recurrence and unplanned hardware removal (p = 1). Overall, we concluded that both techniques are equivocal with no detectable statistical difference. [ABSTRACT FROM AUTHOR]

BackgroundThe treatment of severely displaced Rockwood and Wilkins' type C (RWC) thumb metacarpal basal fractures remains controversial in children. This retrospective study aimed to compare the efficacy of two treatment methods, open vs. closed reduction with pinning of such injuries.MethodsThis study included 30 patients with open physes, 14 boys and 16 girls, who all received either closed or open reduction treatment. The primary outcomes of interest included healing time, complications, and functional results, which were evaluated using the improved Mayo score standard. The minimum follow-up period was 24 months, with a mean of 30.3 months (range 24.0–45.0 months). Statistical significant was defined as P

Background: The role of prophylactic pinning of the contralateral hip in unilateral SCFE is well established in patients with risk factors for developing contralateral slip. The effect of prophylactic pinning on the growth and morphology of the hip is not well documented in the literature. We aimed to study the effect of prophylactic pinning on the residual growth and morphology of the proximal femur. Materials & Methods: The institutional database was searched for all unilateral SCFE cases for the period 2011 to 2020. A total of 171 unilateral SCFE cases were identified. All the radiographs were scanned and those patients who had follow-up X-rays till skeletal maturity were included in the study. Prophylactic pinning was performed using 6.5 mm fully threaded cancellous screws in supine position on a radiolucent table. The following radiological parameters were measured on the post-operative X-rays and at skeletal maturity: (i) neck length (NL), (ii) neck-shaft angle (NSA), (iii) femoral offset (FO), (iv) articulo-trochanteric distance (ATD) and (iv) tip-apex distance (TAD) by two different observers. Results: The mean age of the cohort was 13.7 years. ATD decreased from the mean value of 25.67 mm in post-operative radiographs to 20.84 mm in final follow-up radiographs. The NL, FO, and TAD were found to be increasing with age with mean final follow-up values of 55.35 mm, 41.41 mm, and 6.19 mm respectively compared to post-operative mean values of 50.95 mm, 37.4 mm, and 4.69 mm. There was no significant change in the neck-shaft angle. The mean post-operative NSA was 132.9° and it was 131.8° at final follow-up radiographs. Conclusion: Prophylactic pinning in unilateral SCFE does not stop the growth of the proximal femur completely. The ATD decreases in all the patients with prophylactic screw fixation probably due to the discrepancy in growth between the trochanteric apophysis and proximal femoral physis. The clinical effects of this subtle change in the morphology of the proximal femur need further investigation. Level of Evidence: Level IV Case series. [ABSTRACT FROM AUTHOR]

Current-voltage characteristics have been calculated for a high-temperature superconductor containing triangular and square periodic arrays of pinning centers with various disorder rates. Non-monotonic dependences of critical current density on the disorder rate have been obtained for the triangular lattice, showing that a perfectly ordered lattice provides smaller critical currents than that with minor distortions, especially at high magnetic fields. For the square lattice, the critical current was mostly declining, with minor peaks at small disorder rates. A thorough analysis of the vortex dynamics has been done, showing the differences in the way vortices move through the disordered lattice and how their paths affect the critical current density. [ABSTRACT FROM AUTHOR]

The analysis of possible current distributions when passing current through a periodically modulated long Josephson contact located in an external magnetic field is carried out. An approach based on the analysis of continuous configuration modification proceeding in the direction of Gibbs potential reduction is used for the calculation. The case when the pinning parameter is less than the critical value is considered. It is shown that at any value of the external magnetic field, there is a critical value of the transport current, when exceeded, the situation ceases to be stationary, as a result of which energy passes into radiation and heat, i.e., currents cease to be persistent. The value of the critical current is determined by the value of the magnetic field at which the vortices begin to fill the entire length of the contact. With an increase in the external magnetic field, the critical value of the current decreases. [ABSTRACT FROM AUTHOR]

The transport properties of niobium films and strips fabricated on Y3Fe5O12 single-crystal films with the (111) and (100) orientations are studied in a wide temperature range from 300 to 4 K. It is shown that a decrease in the temperature of the superconducting transition and its broadening are more significant for the (111) orientation of the films, despite the fact that numerous magnetic-domain walls are localized under the niobium strips and should enhance superconductivity. It is shown that the dependence of the niobium resistance on the direction of magnetization and current is observed only in narrow and thin niobium strips and disappears as they thicken. Rotation of the in-plane magnetic field makes it possible to effectively switch the resistance of such structures in the region of an extended superconducting transition. A scheme for creating a diode effect on niobium strips is proposed and implemented. [ABSTRACT FROM AUTHOR]

Composite magnetic nanostructures are a subject of high research interest, as they provide a number of exciting effects absent in live nature. Among others, much attention has been paid to the studies of exchange coupling in antiferromagnetic/ferromagnetic (AFM/FM) films, which leads to the pinning effect. It manifests itself as a widening and shift of the magnetic hysteresis loop with respect to zero value of the external magnetic field oriented along the pinning direction. In this work, we report on comparative studies of linear and nonlinear magneto-optical effects under the laser-induced switching of the pinning effect in IrMn/CoFe films of various thickness of the ferromagnetic CoFe layer. We found that the magneto-optical response of the pinned AFM/FM nanofilms appears with different hysteresis loop parameters in the transverse magneto-optical Kerr effect (MOKE) and interface-sensitive magnetization-induced second harmonic generation (SHG), indicating the diversity of the magnetic effects at interfaces compared to the bulk of the films. [ABSTRACT FROM AUTHOR]

The intensive development of hydrogen technologies has made very promising applications of one of the cheapest and easily produced bulk MgB2-based superconductors. These materials are capable of operating effectively at liquid hydrogen temperatures (around 20 K) and are used as elements in various devices, such as magnets, magnetic bearings, fault current limiters, electrical motors, and generators. These applications require mechanically and chemically stable materials with high superconducting characteristics. This review considers the results of superconducting and structural property studies of MgB2-based bulk materials prepared under different pressure–temperature conditions using different promising methods: hot pressing (30 MPa), spark plasma sintering (16–96 MPa), and high quasi-hydrostatic pressures (2 GPa). Much attention has been paid to the study of the correlation between the manufacturing pressure–temperature conditions and superconducting characteristics. The influence of the amount and distribution of oxygen impurity and an excess of boron on superconducting characteristics is analyzed. The dependence of superconducting characteristics on the various additions and changes in material structure caused by these additions are discussed. It is shown that different production conditions and additions improve the superconducting MgB2 bulk properties for various ranges of temperature and magnetic fields, and the optimal technology may be selected according to the application requirements. We briefly discuss the possible applications of MgB2 superconductors in devices, such as fault current limiters and electric machines.

The changes in the superconducting properties of high-temperature superconducting tapes of the second generation within a wide range of temperatures and applied magnetic fields up to 7 T before and after irradiation with gold and nickel ions were studied using the vibrational magnetometer technique. We assume the experimental results obtained to be related to a different mechanism of vortex structure pinning in the samples. [ABSTRACT FROM AUTHOR]

We construct several examples related to the scaling limits of energy minimizers and gradient flows of surface energy functionals in heterogeneous media. These include both sharp and diffuse interface models. The focus is on two separate but related issues: the regularity of effective surface tensions and the occurrence of zero mobility in the associated gradient flows. On regularity, we build on the 2014 theory of Chambolle, Goldman, and Novaga to show that gradient discontinuities in the surface tension are generic for sharp interface models. In the diffuse interface case, we only show that the laminations by plane-like solutions satisfying the strong Birkhoff property generically are not foliations and do have gaps. On mobility, we construct examples in both the sharp and diffuse interface case where the homogenization scaling limit of the L² gradient flow is trivial, that is, there is pinning at every direction. In the sharp interface case, these are related to examples previously constructed for forced mean curvature flow in Novaga and Valdinoci's 2011 paper. [ABSTRACT FROM AUTHOR]

Background: The most common treatment modality for supracondylar humerus fractures (SCHFs) in children is closed reduction and percutaneous pinning (CRPP). Nonetheless, debate persists regarding the optimal technique used. Therefore, the purpose of our study was to investigate the impact of surgeon experience, surgeon subspecialty and pin configuration on short-term radiological outcomes following CRPP of displaced SCHFs. Methods: Patients less than 14 years of age who underwent CRPP for displaced SCHFs in the prone position between January 2018 and December 2022 were analyzed. Patients were separated into subgroups based on fracture type (low vs. high sagittal), pin configuration (lateral, cross, other), number and configuration of K-wires and first operator surgical experience. The following outcome measurements were collected: postoperative Baumann angle (BA), Shaft-Condylar angle (SCA), surgical duration (SD), duration of radiation exposure (DRE) and number of clinical and radiological follow-ups (FU). Results: A total of 44 patients with a mean age of 6 ± 2.5 years were included in the final analysis. The mean post-operative BA and SCA were 74.8° ± 4.9° and 37.7° ± 10.2°, respectively. No significant differences were found in the post-operative Baumann's angle or SCA among the subgroups. Regarding secondary outcomes, no differences were found among each subgroup regarding SD, DRE and FUs. Conclusion: Short-term radiological outcomes following the treatment of SCHFs treated in the prone position are not affected by fracture patterns and pinning configuration, regardless of the surgeon's years of experience or subspecialty. [ABSTRACT FROM AUTHOR]

The pinning of domain walls in cobalt micropowders, nanopowders, and nanowires is studied by the double-pulse spin-echo NMR method under an additional magnetic video pulse. Cobalt micropowders are obtained by melting in an induction furnace. Nanopowders are produced using electron beam technology and chemical deposition. This chemical deposition reaction is carried out in an external magnetic field to obtain nanowires. The pinning in these systems is measured as a function of the long-term magnetic video pulse and its amplitude. It is established that the magnetic video pulse area is constant for all its threshold values corresponding to the beginning of the double-pulse echo signal suppression. The linear nature of the pinning dependence on the external magnetic field magnitude in cobalt micropowders in a wider range of the external magnetic field change compared to lithium ferrite is presented. Alternative information about the pinning strength of domain walls in magnets can also be obtained by studying the magnetic video pulse influence on the magnetic echo signal formed by the joint action of radio frequency and magnetic pulses. These NMR methods can be used for microscopic control of the domain wall properties in the studied magnets with the aim of their potential use in functional materials, memory devices, and sensors. [ABSTRACT FROM AUTHOR]

The aim of this article is to study the magnetic Ginzburg–Landau functional with an oscillating pinning term. We consider here oscillations of the pinning term that are much faster than the coherence length ε > 0, which is also the inverse of the Ginzburg–Landau parameter. We study both the case of a periodic potential and of a random stationary ergodic one. We prove that we can reduce the study of the problem to the case where the pinning term is replaced by its average in the periodic case and by its expectation with respect to the random parameter in the random case. In order to do that, we use a decoupling of the energy (detailed in Lassoued and Mironescu’s 1999 paper) that leads us to the study of the convergence of a scalar positive minimizer of the Ginzburg– Landau energy with pinning term and with homogeneous Neumann boundary conditions. We prove uniform convergence of this minimizer towards the mean value of the pinning term by using a blowup argument and a Liouville-type result for non-vanishing entire solutions of the real Ginzburg– Landau/ Allen–Cahn equation, due to the results of Farina (2003). [ABSTRACT FROM AUTHOR]

Background: Slipped capital femoral epiphysis (SCFE) represents a relatively common hip disorder in adolescents. The present retrospective study analyzes the correlation between age, severity of the slip and physeal stability and the functional outcomes, as well as the ability to return to previous physical activity (PA) of patients surgically treated with either pining in situ (PIS) or the modified Dunn (MD) procedure (anatomical reduction of the slipped epiphysis). Methods: The present research is a retrospective observational study of patients surgically treated for SCFE from 2010 to 2015. The sample was divided into two groups: those treated with PIS and those with the MD procedure. Univariate and multivariate logistic regression analyses were performed to determine the relationship between age, Loder classification (stable/unstable), as well as Southwick slip angle (severity of the slip) to return to previous PA. Furthermore, linear regression was used to investigate the association of the above predictor variables to Oxford and Harris hip scores (HHS). Results: A total of 32 patients were identified (16 treated with PIS and 16 with the MD procedure). None of the examined predictor variables (age, Southwick slip angle, Loder classification) had statistically significant effect on the ability to return to previous PA in either the in situ or Dunn group. Univariate analysis showed that higher patients' age at the time of surgery was related to worse HHS and Oxford scores in both the PIS and MD groups. Unstable hips seem to affect unfavorably the HHS. Conclusions: The present study did not reveal any relationship between the age, degree of the Southwick slip angle, the stability of the physis, and the return to PA. Exploration of additional confounding factors are warranted to better understand the physis-related impact on the functional outcomes in both groups. [ABSTRACT FROM AUTHOR]

Holes drilled in a type-II superconductor trap the magnetic flux. Following Clem's flux pinning model, we consider surface pinning as a mechanism for compressing the magnetic flux in the holes. Estimations of the trapped magnetic flux demonstrate that the holes with the diameter up to 2 mm are advantageous for bulk single-crystal REBCO samples. The REBCO films and tapes can be improved by the holes with diameter smaller than 10 μm. [ABSTRACT FROM AUTHOR]

In-situ (10 vol%) TiB/Ti–Al–4V composites were prepared by employing cold isostatic pressing and vacuum sintering. The “pinning” effects of TiB whiskers on the hot deformation behavior and dynamic recrystallization of composites in the temperature range of 1000–1200 °C with strain rates from 0.01 to 10 s−1 were investigated in terms of flow behavior, hot-processing maps, and microstructural evolution. No flow instability region within the specified range was found. The dominant deformation mechanisms of the composites were CDRX and DDRX in the (α+β) and β regions, respectively. Owing to the “pinning” effect, prior-α could generate more grain boundaries by HAGB immigration to move through TiB whiskers. In the β region, owing to the deformation incompatibility and the “pinning” effect, more bulging of grain boundaries induced by TiB whiskers resulted in more nucleation sites for DDRX. On account of the “pinning” effect, TiB whiskers enhanced microstructural refinement by restricting grain growth.

The Monte Carlo method was used to numerically calculate the magnetization curves of a model sample of magnesium diboride containing various concentrations of point defects. The dynamics of penetration, propagation, and trapping of Abrikosov vortices have been investigated. The calculations showed a qualitative agreement with the experimental data obtained on a multifilamentary polycrystalline commercial magnesium diboride sample. Similar simulations were performed for a cuprate high-temperature superconductor YBCO to compare the magnetic characteristics of two materials with identical pinning distributions. Differences in the irreversibility fields and total penetration fields have been shown, as well as a twofold difference in the areas of magnetization loops for these materials, which is important for practical applications. It has been shown that the observed features can be associated with the differences in vortex-vortex interactions and different pinning efficiencies resulting from the differences in the characteristic lengths. A proposal has been made that the greater rigidity of the vortex lattice in magnesium diboride than in YBCO should lead to a greater increase in magnetization and critical current when artificial defects are added. [ABSTRACT FROM AUTHOR]

In this work, we studied the fixation of magnetic vortices (pinning effect) on "inelastic" and "elastic" twins, whose wedge-shaped peaks in the direction of twinning do not reach the crystal surface. The effectiveness of the "elastic" twins effect as pinning centers was studied by measuring of the critical transport current Jc in single crystals YBa2Cu3O7–x. The presented experimental data indicate that the "elastic" twins boundaries are effective pinning centers of the magnetic flux lines in single crystals of the compound under study. The main pinning centers of the vortices are dislocation clusters forming at the vertices of the "elastic" twins. The dislocation lines are located in the twin plane and, if the orientation of the magnetic vortices and dislocation lines coincide, the energy of the vortices decreases, the pinning force appears, fixing their location, which ultimately leads to an increase in the critical density of the transport electric current. [ABSTRACT FROM AUTHOR]

In this work, we studied the fixation of magnetic vortices (pinning effect) on "inelastic" and "elastic" twins, whose wedge-shaped peaks in the direction of twinning do not reach the crystal surface. The effectiveness of the "elastic" twins effect as pinning centers was studied by measuring of the critical transport current Jc in single crystals YBa2Cu3O7–x. The presented experimental data indicate that the "elastic" twins boundaries are effective pinning centers of the magnetic flux lines in single crystals of the compound under study. The main pinning centers of the vortices are dislocation clusters forming at the vertices of the "elastic" twins. The dislocation lines are located in the twin plane and, if the orientation of the magnetic vortices and dislocation lines coincide, the energy of the vortices decreases, the pinning force appears, fixing their location, which ultimately leads to an increase in the critical density of the transport electric current. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to compare different pinning techniques for distal radius with Salter-Harris type I fracture. Computed Tomography (CT) images of a distal antebrachium of the 6.5 kg, growing, 6-month-old intact male mongrel dog were 3D-printed with Polycarbonate (PC) material. Twenty-one synthetic bones were classified into three groups. Cross pinning, Parallel pinning, and HK2 pinning techniques were applied to each group. A compressive shear test was applied to each group, and the results at 1 mm, 2 mm, and 3 mm displacement and the load at failure were analyzed through statistical software. It was found that there was no significant difference (p = 0.156) among the three groups at 1 mm displacement load. When comparing loads at 2 mm displacement, a significant difference (p = 0.024) was observed between the HK2 pinning group (224.6 ± 21.8 N) and the Parallel pinning group (188.1 ± 18.2 N). When comparing loads at 3 mm displacement, the HK2 pinning group (392.9 ± 35.6 N) and Cross pinning group (379.4 ± 37.6 N) showed significantly higher (p = 0.006, p = 0.028) loads than the Parallel pinning group (329.1 ± 25.1 N). In the comparison of maximum failure loads, a significant difference (p = 0.029) was observed between the HK2 pinning group (546.6 ± 47.5 N) and the Parallel pinning group (478.6 ± 44.3 N). In conclusions, the reduction of the distal radius with Salter-Harris type I fractures using the novel HK2 pinning technique in 3D-printed bones was similar or superior to other pinning techniques. [ABSTRACT FROM AUTHOR]

ObjectiveIn the past, obviously displaced lateral condyle fractures of the humerus in children were treated satisfactorily with open reduction and internal fixation (ORIF). However, in recent years, more studies have mentioned closed reduction and percutaneous pinning (CRPP) of these fractures.MethodsIn this retrospective investigation, the radiographic and clinical results of patients with these fractures that were initially managed with CRPP were newly classified. We classified these fractures into three groups according to the degree and pattern of fracture displacement as identified on four radiographic images. In Type I, the fracture is unstable and displacement is ≥2 mm; In Type II degree I, the fracture is unstable and displacement is >2 mm, with single rotation of fragment; In Type II degree II, the fracture is unstable and displacement is >2 mm, with single rotation of fragment, with rotation of fragment and antero-proximal displacement; In Type III, the fracture is unstable and displacement is >2 mm, with posterior dislocation of elbow joint. We also designed an algorithm for closed reduction of these fractures according to this new classification.ResultsWe retrospectively analyzed the radiographic and clinical results of 37 unstable fractures (in 22 boys and 15 girls) that were treated with closed reduction. Twenty-one of 25 (84.0%) type I fractures, which could have been reduced to within 2 mm of residual displacement, were treated with closed reduction and pinning with 2 or 3 Kirschner wires (K wires). Three of 5 (60.0%) type II degree I, 3 of 4 (75.0%) type II degree II, and 3 of 3 (100%) type III fractures were treated with CRPP. In 4 of 25 (16.0%) type I, 2 of 5 (40.0%) type II degree I and 1 of 4 (25.0%) type II degree II fractures, closed reduction failed, so ORIF was implemented. There were no complications, such as nonunion, osteonecrosis of the capitellum, superficial or deep infection, malunion, cubitus varus or valgus, or early physeal arrest.ConclusionAlthough the management of type III fractures may not be more difficult than type II fractures with a rotated fracture fragment, as elbow dislocations are usually easy reducible. This retrospective study showed that type III fractures should not be ignored as a lateral condyle fracture that can be cured with CRPP and that lateral humeral condyle fractures with obvious displacement and rotation can be initially treated with CRPP to achieve satisfactory recovery of the elbow. Kirschner wire (K wire) fixation is recommended to avoid reoperation or anesthesia for hardware removal.

The domain wall (DW) motion in ferromagnetic nanostructures is an interesting research area both for fundamental understanding and for spintronic device applications. In this work, we have investigated the effect of vortex domain wall (VDW) chirality on the splitting and recombination process in ferromagnetic nanowire with an anti-dot. A tail-to-tail VDW initially splits into two transverse DWs (TDW) and recombination of TDWs leads to either 360° DW formation or annihilation. We have observed that the chirality of VDW affects the magnetization reversal within the nanowire where a clockwise VDW results in 360° DW formation via recombination. However, an anticlockwise VDW annihilates the two TDWs. This chirality-dependent recombination is observed only above a particular anti-dot width (> 100 nm). When the anti-dot width is below 100 nm, the splitting and recombination process is independent of the chirality of the VDWs. Interestingly, for head-to-head VDW, a similar behavior is observed, however, with an opposite chirality leading to a cross-symmetry. The spin configuration around the pinning site in the nanowire plays a vital role in DW pinning and reversal mechanism. The TDW in the branch can proceed or gets obstructed depending on the relative orientation between the DW chirality and magnetization in the nanowire and thus dictates the formation of 360° DW. [ABSTRACT FROM AUTHOR]

We present the multifrequency measurements of the surface resistance of spark-plasma-sintered MgB 2 performed through a dielectric loaded resonator operating at 16.5 and 26.7 GHz. By normally applying magnetic fields ≤1.2 T to the sample surface, we drove it in the mixed state. By means of data-rooted analysis, we found that the sample vortex dynamics could be fully described within a single-component approach. Pinning phenomena were present and characterized by a depinning frequency smaller than the measurement ones. The multiband nature of the superconductor emerged in the flux-flow resistivity, whose field dependence could be interpreted well within theoretical models. By exploiting them, the upper critical field was extracted in the low-temperature range, which exhibited a consistent temperature trend with the values obtained at the onset of the resistive transition near T c , and was well in line with literature data on other polycrystalline samples. [ABSTRACT FROM AUTHOR]

The characteristics of fixation centers of cobalt domain walls are studied by two alternative methods of nuclear magnetic resonance as an echo signal under the influence of an additional magnetic video-pulse: by the effect of a magnetic video-pulse on a two-pulse echo signal and by the threshold for generating a magnetic echo signal with the combined influence of a radiofrequency pulse and a magnetic video-pulse on a sample. The degree of fixation of cobalt domain walls is shown to depend on the external constant magnetic field in a wider range as compared to lithium–zinc ferrite because of its higher magnetic rigidity. [ABSTRACT FROM AUTHOR]

Nano liquid-containing porous surfaces have been widely used in porous self-lubricating materials such as spacecraft momentum wheel bearing assemblies. The temperature of the lubricant for the frictional heat has an important effect on the self-lubricating behavior on the pores surface. To reveal the depinning and spreading characteristics of the exuded thermal droplets at the orifices, the kinetic model of the lubricant exudation under the influence of the thermophysical field was established by the molecular dynamics. The mechanical mechanism of liquid exudation assisted by the thermophysical field is revealed combined with the pinning of the three-phase contact lines during the nucleation of droplets and the spreading characteristics of the depinning droplets. The results indicate that as the temperature of the liquid lubricant increases, the density of the liquid near-wall of the pore decreases and the thermal movement of the liquid molecules enhances, increasing the exudation velocity and the slip length of liquid at the wall. And the pinning force on the three-phase contact line and the depinning energy barrier of droplets all decrease. Higher temperatures promote the spreading of droplets to form a lubricating film. This research contributes to enriching the kinetic theory of liquid exudation from porous liquid-containing friction surfaces. • Slip length of liquid lubricant in the pore under thermal influence increases. • Pinning force and depinning energy barrier of droplet decrease for the thermal effect. • The slip and pinning properties help liquid exudation and spreading to form film. [ABSTRACT FROM AUTHOR]

Composite magnetic nanostructures are a subject of high research interest, as they provide a number of exciting effects absent in live nature. Among others, much attention has been paid to the studies of exchange coupling in antiferromagnetic/ferromagnetic (AFM/FM) films, which leads to the pinning effect. It manifests itself as a widening and shift of the magnetic hysteresis loop with respect to zero value of the external magnetic field oriented along the pinning direction. In this work, we report on comparative studies of linear and nonlinear magneto-optical effects under the laser-induced switching of the pinning effect in IrMn/CoFe films of various thickness of the ferromagnetic CoFe layer. We found that the magneto-optical response of the pinned AFM/FM nanofilms appears with different hysteresis loop parameters in the transverse magneto-optical Kerr effect (MOKE) and interface-sensitive magnetization-induced second harmonic generation (SHG), indicating the diversity of the magnetic effects at interfaces compared to the bulk of the films.

Using the Monte Carlo method, the vertical z-component of levitation force acting on a thin HTS film in a field simulating the inhomogeneous field of a permanent magnet is calculated within the framework of a two-dimensional model of a layered HTS. The dependences of the vertical component of the levitation force on the distance to the magnet are obtained at different concentrations of pinning centers and at temperatures ranging from 1 to 50 K. A case is simulated in which a superconducting sample starts moving towards a magnet from infinity and then moves away from the magnet. The change of sign of the levitation force corresponds to the movement away from the magnet when trapped magnetic flux is present in the sample. The presence of hysteresis of the levitation force is demonstrated. It is also shown that the levitation force does not change its sign in a defect-free sample and in a sample with a large number of defects. This is due to the peculiarities of the distribution of vortex density and currents in the sample during magnetization process. [ABSTRACT FROM AUTHOR]