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The problem of a thin superconducting film in a parallel magnetic field, first discussed in the classical paper by Ginzburg and Landau for temperatures close to the critical, is revisited with the help of the microscopic BCS theory for arbitrary temperatures taking pair-breaking and transport scattering into account. While confirming experimental findings of the $T_c$ enhancement by the magnetic field, we find that the transport scattering pushes the phase transition curve to higher fields and higher temperatures for nearly all practical scattering rates. Still, the $T_c$ enhancement disappears in the dirty limit. We also consider intriguing changes, such as re-entrant superconductivity, caused to the phase boundary by pair-breaking magnetic ions spread on one of the film faces. These features await experimental verification.

International audience; The London penetration depth λ(T) was measured in a single crystal of V3Si. The superfluid density obtained from this measurement shows a distinct signature of two almost decoupled superconducting gaps. This alone is insufficient to distinguish between s± and s++ pairing states, but it can be achieved by studying the effect of controlled nonmagnetic disorder on the superconducting transition temperature Tc. For this purpose, the same V3Si crystal was sequentially irradiated by 2.5-MeV electrons three times, repeating the measurement between the irradiation runs. A total dose of 10C/cm2 (6.24×1019 electrons/cm2) was accumulated, for which Tc changed from 16.4 K in a pristine state to 14.7 K (9.3%). Not only is this substantial suppression impossible for a single isotropic gap, but also it is not large enough for a sign-changing s± pairing state. Our electronic band structure calculations show how five bands crossing the Fermi energy can be naturally grouped to support two effective gaps, not dissimilar from the physics of iron pnictides. We analyze the results using two-gap models for both λ(T) and Tc which describe the data very well. Thus the experimental results and theoretical analysis provide strong support for an s++ superconductivity with two unequal gaps, Δ1(0)≈2.53meV and Δ2(0)≈1.42meV, and a very weak interband coupling in the V3Si superconductor.

The upper critical field $H_{c2} $, the field $H_{c3}$ for nucleation of the surface superconductivity, and the thermodynamic $H_c $ are evaluated within the weak-coupling theory for the isotropic s-wave case and arbitrary transport and pair-breaking scattering. We find that for the standard geometry of a half-space sample in a magnetic field parallel to the surface, the ratio ${\cal R}=H_{c3}/H_{c2}$ is within the window $1.55\lesssim {\cal R}\lesssim 2.34$, regardless of temperature, magnetic or non-magnetic scattering. While the non-magnetic impurities tend to flatten the ${\cal R}\left(T\right)$ variation, the magnetic scattering merely shifts the maximum of ${\cal R}\left(T\right)$ to lower temperatures. Surprisingly, while reducing the transition temperature, magnetic scattering has a milder impact on ${\cal R}$ than the non-magnetic scattering. The surface superconductivity is quite robust; in fact, the ratio ${\cal R}\approx 1.7$ even in the gapless state. We used Eilenberger's energy functional to evaluate the condensation energy $F_c$ and the thermodynamic critical field $H_c$ for any temperature and scattering parameters. By comparing $H_{c2} $ and $H_{c}$, we find that unlike the transport scattering, the pair-breaking pushes materials toward type-I behavior. We find a peculiar behavior of $F_c$ as a function of the pair-breaking scattering parameter at the low-$T$ transition from gapped to gapless phases, which has recently been associated with the topological transition in the superconducting density of states.

A potent anti-inflammatory effect and wide application of corticosteroids were the origin of their extensive use for treatment of diseases and injuries of the shoulder joint. The authors describe a clinical case of tumor-like cyst in the proximal humerus after intra-articular injection of glucocorticosteroid (GCS) in a 43 year old woman. Current medical literature reports various complications following GCS injections but the authors found no other cases of tumor-like cyst in proximal humerus associated with intra-articular GCS injection. This can be an underestimated phenomenon or a unique case. In any case, all physicians performing treatment and diagnostics medication blockades of the large joints should be aware of this occurrence. The authors assume that such complication can be prevented by clear understanding of shoulder joint anatomy and current visualization techniques such as ultrasound navigation.

A phenomenon of abnormally weak absorption of very-high-energy cosmic-ray hadrons in lead is discussed. This phenomenon was first observed in Tien-Shan high-altitude experiments in hadronic cores of extensive air showers and has encouraged to introduce the hypothesis of a so-called long-flying or penetrating cosmic-ray component. A similar effect was detected later with deep uniform lead X-ray emulsion chambers (XREC) at the Pamirs. Experiments, which are sensitive to the production of charmed hadrons in the forward kinematic region (xLab ≳ 0.1), have been carried out at the Tien-Shan and Pamirs with exposing two-storey XRECs with large air gaps to prove explanation of the experimental results with high charm production cross section $${\sigma _{pp \to c\bar c}} \sim 8$$ at xLab ≳ 0.1 at ⟨ELab⟩ ∼ 75 TeV. This $${\sigma _{pp \to c\bar c}}$$ value makes it possible to reproduce the experimental hadron-absorption curve observed with XRECs, including curve’s bending at a depth of ∼70 c.u.

Background: FOLFOX (folinic acid, 5-fluorouracil and oxaliplatin) is the most commonly used chemotherapy regimen for the treatment of colorectal cancer. FOLFOX is administered in 14-day cycles, though toxicities frequently lead to unplanned delays. We report the incidence of unplanned delays among patients receiving FOLFOX and describe the reasons for delays. Methods: We conducted a retrospective analysis of patients receiving FOLFOX chemotherapy for colorectal cancer. Patients were treated at one of two tertiary cancer centers between January 2012 and April 2016. Cycles 2–6 were assessed for delays, and treatments were considered delayed when the interval from prior treatment was >18 days. Reasons for unplanned delays were categorized based on review of clinical records. Results: We identified 214 patients receiving FOLFOX as standard-of-care therapy. The median age was 59 years, and 55% were female. Of 961 evaluable treatment cycles, 124 (13%) had unplanned delays, and 92 of 214 patients (43%) had one or more unplanned delays in cycles 2–6. Cytopenias (neutropenia and/or thrombocytopenia) were the most common cause of unplanned delays, affecting 34% of patients and accounting for 74 of 124 unplanned delays (60%). Conclusions: Delays are common during FOLFOX chemotherapy, with 43% of patients having at least one unplanned delay prior to completing cycle 6. Neutropenia and thrombocytopenia were the leading causes of unplanned delays. Our findings justify the development of systematic approaches for preventing unplanned delays, such as standardized laboratory treatment criteria and/or proactive dose adjustment strategies.

The magnetic field of vortices in anisotropic superconducting films is considered in the framework of anisotropic London approach. It is found that at distances large relative to the core size, the magnetic field normal to the film surface may change sign. We find that the magnetic field attenuates at large distances as $1/r^3$ as it does in isotropic films, but the anisotropy induces an angular dependence to the supercurrents which causes the sign of the field to change for anisotropy parameters $\gamma=\lambda_2/\lambda_1>\sqrt{2}$ in some parts of the $(x,y)$ plane., Comment: 8 pages, 12 figures

The magnetic field of moving vortices in anisotropic superconductors is considered in the framework of time-dependent London approach. It is found that at distances large relative to the core size, the field may change sign that alludes to a non-trivial intervortex interaction which depends on the crystal anisotropy and on the speed and direction of motion. These effects are caused to the electric fields and corresponding normal currents which appear due to the moving vortex magnetic structure. We find that the motion related part of the magnetic field attenuates at large distances as $1/r^3$ unlike the exponential decay of the static vortex field. The electric field induced by the vortex motion decreases as $1/r^2$., Comment: 9 pages, 10 figures

The magnetic field hz of a moving Pearl vortex in a superconducting thin-film in (x,y) plane is studied with the help of the time-dependent London equation. It is found that for a vortex at the origin moving in +x direction, hz(x,y) is suppressed in front of the vortex, x&gt, 0, and enhanced behind (x&lt, 0). The distribution asymmetry is proportional to the velocity and to the conductivity of normal quasiparticles. The vortex self-energy and the interaction of two moving vortices are evaluated.

We take account of normal currents that emerge when vortices move. Moving Abrikosov vortices in the bulk and Pearl vortices in thin films are considered. Velocity dependent distributions of both normal and persistent currents are studied in the frame of time-dependent London equations. In thin films near the Pearl vortex core, these distributions are intriguing in particular., Comment: 8 pages,10 figures. arXiv admin note: text overlap with arXiv:2102.00073

We study the effects of anisotropic order parameters on the temperature dependence of London penetration depth anisotropy ${\ensuremath{\gamma}}_{\ensuremath{\lambda}}(T)$. After ${\mathrm{MgB}}_{2}$, this dependence is commonly attributed to distinct gaps on multiband Fermi surfaces in superconductors. We have found, however, that the anisotropy parameter may depend on temperature also in one-band materials with anisotropic order parameters $\mathrm{\ensuremath{\Delta}}(T,{\mathbit{k}}_{F})$; a few such examples are given. We have also found that for different order parameters, the temperature dependence of $\mathrm{\ensuremath{\Delta}}(T)/\mathrm{\ensuremath{\Delta}}(0)$ can be represented with good accuracy by the interpolation suggested by Einzel [J. Low Temp. Phys 131, 1 (2003)], which simplifies considerably the evaluation of ${\ensuremath{\gamma}}_{\ensuremath{\lambda}}(T)$. Of particular interest are mixed order parameters of two symmetries for which ${\ensuremath{\gamma}}_{\ensuremath{\lambda}}(T)$ may go through a maximum for a certain relative weight of two phases. Also, for this case we find that the ratio ${\mathrm{\ensuremath{\Delta}}}_{max}(0)/{T}_{c}$ may exceed substantially the weak-coupling limit of 1.76. It, however, does not imply strong coupling; rather, it is due to significantly anisotropic angular variation of $\mathrm{\ensuremath{\Delta}}$.

The anisotropic London equations taking into account the normal currents are derived and applied to the problem of the surface impedance in the Meissner state of anisotropic materials. It is shown that the complex susceptibility of the anisotropic slab depends on the orientation of the applied microwave field relative to the crystal axes. In particular, the anisotropic sample in the microwave field is subject to a torque, unless the field is directed along one of the crystal principle axes.

The magnetic response of $\mathrm{Ca}\mathrm{K}{({\mathrm{Fe}}_{0.949}{\mathrm{Ni}}_{0.051})}_{4}{\mathrm{As}}_{4}$ was investigated by means of the muon spin rotation/relaxation. The long-range commensurate magnetic order sets in below the N\'eel temperature ${T}_{\mathrm{N}}=50.0(5)$ K. The density-functional theory calculations have identified three possible muon stopping sites. The experimental data were found to be consistent with only one type of magnetic structure, namely, the long-range magnetic spin-vortex-crystal order with the hedgehog motif within the $ab$ plane and the antiferromagnetic stacking along the $c$ direction. The value of the ordered magnetic moment at $T\ensuremath{\approx}3$ K was estimated to be ${m}_{\mathrm{Fe}}=0.38(11){\ensuremath{\mu}}_{\mathrm{B}}$ (${\ensuremath{\mu}}_{\mathrm{B}}$ is the Bohr magneton). A microscopic coexistence of magnetic and superconducting phases accompanied by a reduction of the magnetic order parameter below the superconducting transition temperature ${T}_{\mathrm{c}}\ensuremath{\simeq}9$ K is observed. Comparison with 11, 122, and 1144 families of Fe-based pnictides points to existence of correlation between the reduction of the magnetic order parameter at $T\ensuremath{\rightarrow}0$ and the ratio of the transition temperatures ${T}_{\mathrm{c}}/{T}_{\mathrm{N}}$. Such correlations were found to be described by Machida's model for coexistence of itinerant spin-density-wave magnetism and superconductivity [K. Machida, J. Phys. Soc. Jpn. 50, 2195 (1981); S. L. Bud'ko et al., Phys. Rev. B 98, 144520 (2018)].

The self-energy of a moving vortex is shown to decrease with increasing velocity. The interaction energy of two parallel slowly moving vortices differs from the static case by a small term $\ensuremath{\propto}{v}^{2}$; the ``slow'' motion is defined as having the velocity $vl{v}_{c}={c}^{2}/4\ensuremath{\pi}\ensuremath{\sigma}\ensuremath{\lambda}$, where $\ensuremath{\sigma}(T)$ is the conductivity of normal excitations and $\ensuremath{\lambda}(T)$ is London penetration depth. For higher velocities, $vg{v}_{c}(T)$, the interaction energy of two vortices situated along the velocity direction is enhanced and in the perpendicular direction is suppressed compared to the static case.

A simple relation is established between the zero-$T$ penetration depth $\ensuremath{\lambda}(0)$ and the slope of ${\ensuremath{\lambda}}^{\ensuremath{-}2}(T)$ near ${T}_{c}$, similar to Helfand-Werthamer's relation for ${H}_{c2}(0)$ and the slope of ${H}_{c2}(T)$ at ${T}_{c}$ for the isotropic $s$-wave case with nonmagnetic scattering [E. Helfand and N. R. Werthamer, Phys. Rev. 147, 288 (1966)]. When the scattering parameter $\ensuremath{\rho}=\ensuremath{\hbar}v/2\ensuremath{\pi}{T}_{c}\ensuremath{\ell}$ ($v$ is the Fermi velocity and $\ensuremath{\ell}$ is the mean free path) varies from 1 to 10, the coefficient of proportionality between ${\ensuremath{\lambda}}^{\ensuremath{-}2}(0)$ and ${T}_{c}{(d{\ensuremath{\lambda}}^{\ensuremath{-}2}/dT)}_{{T}_{c}}$ changes from 0.43 to 0.38. Combining this relation with the Rutgers thermodynamic identity, one can express $\ensuremath{\lambda}(0)$ in terms of the slope ${(d{H}_{c2}/dT)}_{{T}_{c}}$ and the density of states.

C-terminal truncations of monomeric wild-type alpha-synuclein (henceforth WT-αS) have been shown to enhance the formation of amyloid aggregates both in vivo and in vitro and have been associated with accelerated progression of Parkinson’s disease (PD). The correlation with PD may not solely be a result of faster aggregation, but also of which fibril polymorphs are preferentially formed when the C-terminal residues are deleted. Considering that different polymorphs are known to result in distinct pathologies, it is important to understand how these truncations affect the organization of αS into fibrils. Here we present high-resolution microscopy and advanced vibrational spectroscopy studies that indicate that the C-terminal truncation variant of αS, lacking residues 109–140 (henceforth referred to as 1–108-αS), forms amyloid fibrils with a distinct structure and morphology. The 1–108-αS fibrils have a unique negative circular dichroism band at ∼230 nm, a feature that differs from the canonical ∼218 nm band usually observed for amyloid fibrils. We show evidence that 1–108-αS fibrils consist of strongly twisted β-sheets with an increased inter-β-sheet distance and a higher solvent exposure than WT-αS fibrils, which is also indicated by the pronounced differences in the 1D-IR (FTIR), 2D-IR, and vibrational circular dichroism spectra. As a result of their distinct β-sheet structure, 1–108-αS fibrils resist incorporation of WT-αS monomers.

Aim. To develop a method of acromioclavicular joint stabilization with the TightRope system using «mini-open» technique and to evaluate effectiveness and safety of this surgery. Methods. The study involved 11 patients with Rockwood type III, IV and V acromioclavicular joint dislocation, who underwent «mini-open» surgery of acromioclavicular joint stabilization using the TightRope device. The results were evaluated clinically using the Constant scale and radiologically 3, 6, and 12 months after the treatment. The results obtained were statistically processed and compared to the results of the treatment of patients with the same pathology published in the foreign literature. Results. In the early postoperative period (up to 3 months after the surgery) functional result according to Constant scale in the studied patients varied in the score range of 67.5±16.2. In the period of up to 12 months all patients had 82.5±11.5 score, which corresponds to good and excellent results and does not show significant difference compared to the arthroscopic technique (according to literature data). Complications among observed patients occurred in 18% and were identified in 2 patients (1 case of fixation loss, 1 local skin inflammation in the area of the wound). Conclusion. New surgical techniques allow achieving good and excellent functional results and to improve patient satisfaction.

The Aleutian and Kuril-Kamchatka arcs meet at a triple junction of the Pacific (PAC), Bering (BER), and North American (NAM) plates. We invert GPS observations from the westernmost Aleutian (Komandorsky) Islands and Kamchatka for the fault locking depth and block motion in the far western Aleutian transform boundary. Three boundary models were considered: (1) only the Aleutian thrust fault without a trench-normal component, (2) only a strike-slip fault in the back arc north of the Komandorsky Islands, and (3) a rigid Komandorsky sliver bounded by the Aleutian and back-arc faults. Observed velocities prefer Model 3, with a secular westward sliver velocity of 51 mm/a relative to NAM (two thirds of the total PAC-NAM motion). The observed velocities are ~10% slower because of elastic strain from boundary faults. The best fitting locking depth of faults bounding the sliver is 12 km, which is similar to depths observed in diverse tectonic environments.

We show on a few examples of one-band materials with spheroidal Fermi surfaces and anisotropic order parameters that anisotropies ${\ensuremath{\gamma}}_{H}$ of the upper critical field and ${\ensuremath{\gamma}}_{\ensuremath{\lambda}}$ of the London penetration depth depend on temperature, a feature commonly attributed to multiband superconductors. The parameters ${\ensuremath{\gamma}}_{H}$ and ${\ensuremath{\gamma}}_{\ensuremath{\lambda}}$ may have opposite temperature dependences or may change in the same direction depending on the Fermi-surface shape and on the character of the gap nodes. For two-band systems, the behavior of anisotropies is affected by the ratios of bands densities of states, Fermi velocities, anisotropies, and order parameters. We investigate in detail the conditions determining the directions of temperature dependences of the two anisotropy factors.

Strains in superconductors due to moving vortices and vortex lattices are discussed. It is shown that the energy stored in elastic strains increases with vortex velocity. For moving vortex lattices, the elastic energy depends on velocity orientation relative to the lattice having minimum for the velocity directed along one of the unit cell vectors of the moving lattice. It is shown that for supersonic motion, the vortex induced stress field has a shape similar to supersonic shock waves., Comment: 6 pages, 2 figures

Temperature dependent $^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy and specific heat measurements for $\mathrm{CaK}{({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Ni}}_{x})}_{4}{\mathrm{As}}_{4}$ with $x=0$, 0.017, 0.033, and 0.049 are presented. No magnetic hyperfine field (i.e., no static magnetic order) down to 5.5 K was detected for $x=0$ and 0.017 in agreement with the absence of any additional feature below superconducting transition temperature ${T}_{c}$ in the specific heat data. The evolution of magnetic hyperfine field with temperature was studied for $x=0.033$ and 0.049. The long-range magnetic order in these two compounds coexists with superconductivity. The magnetic hyperfine field ${B}_{\text{hf}}$ (ordered magnetic moment) below ${T}_{c}$ in $\mathrm{CaK}{({\mathrm{Fe}}_{0.967}{\mathrm{Ni}}_{0.033})}_{4}{\mathrm{As}}_{4}$ is continuously suppressed with the developing superconducting order parameter. The ${B}_{\text{hf}}(T)$ data for $\mathrm{CaK}{({\mathrm{Fe}}_{0.967}{\mathrm{Ni}}_{0.033})}_{4}{\mathrm{As}}_{4}$ and $\mathrm{CaK}{({\mathrm{Fe}}_{0.951}{\mathrm{Ni}}_{0.049})}_{4}{\mathrm{As}}_{4}$ can be described reasonably well by Machida's model for coexistence of itinerant spin density wave magnetism and superconductivity [K. Machida, J. Phys. Soc. Jpn. 50, 2195 (1981)]. We demonstrate directly that superconductivity suppresses the spin density wave order parameter if the conditions are right, in agreement with the theoretical analysis.

In the Dirac theory of the quantum-mechanical interaction of a magnetic monopole and an electric charge, the vector potential is singular from the origin to infinity along certain direction - the so called Dirac string. Imposing the famous quantization condition, the singular string attached to the monopole can be rotated arbitrarily by a gauge transformation, and hence is not physically observable. By deriving its analytical expression and analyzing its properties, we show that the gauge function $\chi({\bf r})$ which rotates the string to another one has quite complicated behaviors depending on which side from which the position variable ${\bf r}$ gets across the plane expanded by the two strings. Consequently, some misunderstandings in the literature are clarified., Comment: 5 pages, 3 figures

The origin of an excess of hadrons observed in deep homogeneous lead X-ray emulsion chambers (XRECs) at depths of more than 70 radiation length units is analyzed. Preliminary experimental data on the absorption of cosmic-ray hadrons in a two-storied XREC with a large air gap, exposed in the Tien Shan mountains, are presented. The chamber was designed to test the hypothesis that the main source of the excess of dark spots detected on X-ray films deep inside the XREC was substantial growth of the charmed-particle production cross section at energy E lab ∼ 75 TeV. The experimental data obtained using a two-storied REC and in experiments with deep homogeneous XRECs are compared to the results from calculations using the FANSY 1.0 model. The comparison shows qualitative agreement between the experimental and the model data, assuming high values of the charmed-particle production cross section when E lab ∼ 75 TeV in the forward kinematic region with x F ≥ 0.1.

We study vortex current distributions in narrow thin-film superconducting strips with the help of analytic expression of the vortex current derived within the London theory. Using definition of the...

Enhanced microwave absorption, larger than that in the normal state, is observed in fine grains of type-II superconductors (MgB2 and K3C60) for magnetic fields as small as a few % of the upper critical field. The effect is predicted by the theory of vortex motion in type-II superconductors, however its direct observation has been elusive due to skin-depth limitations; conventional microwave absorption studies employ larger samples where the microwave magnetic field exclusion significantly lowers the absorption. We show that the enhancement is observable in grains smaller than the penetration depth. A quantitative analysis on K3C60 in the framework of the Coffey–Clem (CC) theory explains well the temperature dependence of the microwave absorption and also allows to determine the vortex pinning force constant.

We use a scanning tunneling microscope to study the superconducting density of states and vortex lattice of single crystals of ${\mathrm{CaKFe}}_{4}{\mathrm{As}}_{4}$. This material has a critical temperature of ${T}_{c}=35$ K, one of the highest among stoichiometric iron based superconductors (FeBSCs), and is comparable to ${T}_{c}$ found near optimal doping in other FeBSCs. We observe quasiparticle scattering from defects with a pattern related to interband scattering between zone centered hole sheets. We measure the tunneling conductance in vortex cores and find a peak due to Caroli--de Gennes--Matricon bound states. The peak is located above the Fermi level, showing that ${\mathrm{CaKFe}}_{4}{\mathrm{As}}_{4}$ is a clean superconductor with vortex core bound states close to the so-called extreme quantum limit. We identify locations where the superconducting order parameter is strongly suppressed due to pair breaking. Vortices are pinned at these locations, and the length scale of the suppression of the order parameter is of order of the vortex core size. As a consequence, the vortex lattice is disordered up to 8 T.

The dissipative currents due to normal excitations are included in the London description. The resulting time dependent London equations are solved for a moving vortex and a moving vortex lattice. It is shown that the field distribution of a moving vortex looses it cylindrical symmetry, it experiences contraction which is stronger in the direction of the motion, than in the direction normal to the velocity $\bm v$. The London contribution of normal currents to dissipation is small relative to the Bardeen-Stephen core dissipation at small velocities, but approaches the latter at high velocities, where this contribution is no longer proportional to $v^2$. To minimize the London contribution to dissipation, the vortex lattice orients as to have one of the unit cell vectors along the velocity, the effect seen in experiments and predicted within the time-dependent Ginzburg-Landau theory., Comment: 6 pages, 5 figures

The 17 July 2017 Komandorsky Islands M_W 7.8 earthquake involved arc-parallel right-lateral patchy strike-slip faulting along ~400 km of the Bering Fracture Zone (BFZ) in the westernmost Aleutian Islands back arc. The large size of the earthquake indicates that the BFZ serves regionally as the primary plate boundary extending from the Near Islands to Kamchatka, with the fore-arc Komandorsky Sliver translating rapidly parallel to the Aleutian Trench. The slip distribution is determined by analysis of seismic, tsunami, and geodetic observations. Fault displacements of 4 to 8.5 m, mostly in the upper 15 km, but with localized extension to 20 to 30 km depth along a ~100 km long segment of the BFZ, are comparable to the possible slip deficit since the last major earthquakes in this region in 1849 and 1858, given an estimated 5.1 cm/yr rate between the Komandorsky Sliver and the Bering Plate.

Effective demagnetizing factors that connect the sample magnetic moment with the applied magnetic field are calculated numerically for perfectly diamagnetic samples of various non-ellipsoidal shapes. The procedure is based on calculating total magnetic moment by integrating the magnetic induction obtained from a full three dimensional solution of the Maxwell equations using adaptive mesh. The results are relevant for superconductors (and conductors in AC fields) when the London penetration depth (or the skin depth) is much smaller than the sample size. Simple but reasonably accurate approximate formulas are given for practical shapes including rectangular cuboids, finite cylinders in axial and transverse field as well as infinite rectangular and elliptical cross-section strips., updated version, corrected typos etc

We revisit the problem of the surface superconductivity nucleation focusing on the detailed study of the critical field $H_{c3}$ as a function of temperature and disorder. Using the semiclassical Eilenberger formalism we find that away from the Ginzburg-Landau region the ratio between the nucleation critical field $H_{c3}$ and the upper critical field $H_{c2}$ deviates strongly from the Saint-James-de Gennes limit. In particular, the $H_{c3}/H_{c2}$ is found to be a nonmonotonic function of temperature, which reaches the maximum for a set of parameters corresponding to a crossover region from ballistic to diffusive scattering, when the mean free path in a bulk of a superconductor is of the same order as zero-temperature superconducting coherence length. We also analyze the robustness of the nucleated phases with respect to diffusive scattering off the sample boundary by solving exactly corresponding eigenvalue problem of an integral equation for the critical field. The implications of these results for the transport in superconductors of various geometries near $H_{c3}$ are briefly discussed. In particular, we present results for the mechanism of magnetoconductivity oscillations due to surface superconductivity effects., 14 pages, 6 figures

The aggregation of the intrinsically disordered protein alpha-synuclein (αS) into amyloid fibrils is thought to play a central role in the pathology of Parkinson’s disease. Using a combination of techniques (AFM, UV-CD, XRD, and amide-I 1D- and 2D-IR spectroscopy) we show that the structure of αS fibrils varies as a function of ionic strength: fibrils aggregated in low ionic-strength buffers ([NaCl] ≤ 25 mM) have a significantly different structure than fibrils grown in higher ionic-strength buffers. The observations for fibrils aggregated in low-salt buffers are consistent with an extended conformation of αS molecules, forming hydrogen-bonded intermolecular β-sheets that are loosely packed in a parallel fashion. For fibrils aggregated in high-salt buffers (including those prepared in buffers with a physiological salt concentration) the measurements are consistent with αS molecules in a more tightly-packed, antiparallel intramolecular conformation, and suggest a structure characterized by two twisting stacks of approximately five hydrogen-bonded intermolecular β-sheets each. We find evidence that the high-frequency peak in the amide-I spectrum of αS fibrils involves a normal mode that differs fundamentally from the canonical high-frequency antiparallel β-sheet mode. The high sensitivity of the fibril structure to the ionic strength might form the basis of differences in αS-related pathologies.

It is of interest to determine the exit angle of a vortex from a superconducting surface, since this affects the intervortex interactions and their consequences. Two ways to determine this angle are to image the vortex magnetic fields above the surface, or the vortex core shape at the surface. In this work we evaluate the field h(x, y, z) above a flat superconducting surface x, y and the currents J(x,y) at that surface for a straight vortex tilted relative to the normal to the surface, for both the isotropic and anisotropic cases. In principle, these results can be used to determine the vortex exit tilt angle from analyses of magnetic field imaging or density of states data., Comment: 5 pages, 4 figures

It is shown that a vortex trapped in one of the banks of a planar edge-type Josephson junction in a narrow thin-film superconducting strip can change drastically the dependence of the junction critical current on the applied field, I c ( H ) . When the vortex is placed at certain discrete positions in the strip middle, the pattern I c ( H ) has zero at H = 0 instead of the traditional maximum of ‘0-type’ junctions. The number of these positions is equal to the number of vortices trapped at the same location. When the junction–vortex separation exceeds ∼ W , the strip width, I c ( H ) is no longer sensitive to the vortex presence. The same is true for any separation if the vortex approaches the strip edges.

We analyze the first ever GPS observations of static surface deformation from a deep earthquake: the 24 May 2013 Mw 8.3 Sea of Okhotsk, 611 km-deep, event. Previous studies of deep earthquake sources relied on seismology and might have missed evidence for slow slip in the rupture. We observed coseismic static offsets on a GPS network of 20 stations over the Sea of Okhotsk region. The offsets were inverted for the best fitting double-couple source model assuming a layered spherical Earth. The seismic moment calculated from static offsets is only 7% larger than the seismological estimate from Global Centroid Moment Tensor (GCMT). Thus, GPS observations confirm shear faulting as the source model, with no significant slow-slip component. The relative locations of the U.S. Geological Survey hypocenter, GCMT centroid, and the fault from GPS indicate slip extending for tens of kilometers across most of the slab thickness.