Oscillating magnetoresistance due to fragile spin structure in metallic GdPd3_3

Studies on the phenomenon of magnetoresistance (MR) have produced intriguing and application-oriented outcomes for decades--colossal MR, giant MR and recently discovered extremely large MR of millions of percents in semimetals can be taken as examples. We report here the investigation of oscillating MR in a cubic intermetallic compound GdPd$_3$, which is the only compound that exhibits MR oscillations between positive and negative values. Our study shows that a very strong correlation between magnetic, electrical and magnetotransport properties is present in this compound. The magnetic structure in GdPd$_3$ is highly fragile since applied magnetic fields of moderate strength significantly alter the spin arrangement within the system--a behavior that manifests itself in the oscillating MR. Intriguing magnetotransport characteristics of GdPd$_3$ are appealing for field-sensitive device applications, especially if the MR oscillation could materialize at higher temperature by manipulating the magnetic interaction through perturbations caused by chemical substitutions.Comment: 10 pages, 7 figures. A slightly modified version is published in Scientific Report

Ferromagnetically correlated clusters in semi-metallic Ru2NbAl Heusler alloy

In this work, we report the structural, magnetic and electrical and thermal transport properties of the Heusler-type alloy Ru2NbAl. From the detailed analysis of magnetization data, we infer the presence of superparamagnetically interacting clusters with a Pauli paramagnetic background, while short-range ferromagnetic interaction is developed among the clusters below 5 K. The presence of this ferromagnetic interaction is confirmed through heat capacity measurements. The relatively small value of electronic contribution to specific heat, gamma (~2.7 mJ/mol-K2), as well as the linear nature of temperature dependence of Seebeck coefficient indicate a semi-metallic ground state with a pseudo-gap that is also supported by our electronic structure calculations. The activated nature of resistivity is reflected in the observed negative temperature coefficient and has its origin in the charge carrier localization due to antisite defects, inferred from magnetic measurements as well as structural analysis. Although the absolute value of thermoelectric figure of merit is rather low (ZT = 5.2*10-3) in Ru2NbAl, it is the largest among all the reported non-doped full Heusler alloys.Comment: 25 pages, 14 figure

Evaluation of osteoporotic trochanteric fractures treated with cement-augmented dynamic hip screw

Background: Dynamic hip screw (DHS) has been the standard treatment for stable trochanteric fracture patterns. However, primary stabilization with dynamic/sliding hip screw is not always successful, especially in osteoporotic fractures. Internal fixation in such a situation may achieve a satisfactory initial fracture site reduction, but late fracture collapse into varus during weight bearing, can lead to a high failure rate. Since 1975, polymethylmethacrylate (PMMA) cement-augmented DHS have been used as a solution in unstable ITFs by adding an anchoring ability to the lag screw.Methods: A series of 33 osteoporotic intertrochanteric fractures were operated with cement augmented dynamic hip screw. One patient lost to follow up. All patients were then allowed partial weight bearing walker aided ambulation under the guidance of physiotherapist on the second or third postoperative day. The patients were followed radio logically and clinically at regular intervals (1st month, than at 3rd month and then at 6th month interval after surgery). Results were graded as excellent (score >31), good (score 24-31), fair (score 16-23), and poor (score <16). Clinical result was given according to Salvati and Wilson scoring.Results: Total 33 patients were taken for the study they were followed for minimum 6 months and at 6 months the clinical outcome was rated as per the Salvati and Wilson scoring system. One patient lost to follow-up. Final clinical results as evaluated by Salvati and Wilson scoring were; excellent in 24 cases (75%), good in 7 cases (21.88%), fair in 1 case (3.12%) and poor in 0 cases (0%). There were no non-union, AVN, implant failure and screw cut-out in our study.Conclusions: The surgical management of intertrochanteric fractures with PMMA augmented DHS provide a stable fixation with moderate pain free early mobilisation and better outcome in osteoporotic patients without the complications of superior screw cut-out, sliding collapse, and with the appropriate placement of bone cement along with proper amount (4-5 ml) of cement we can also reduce the cement related complications such as delayed healing, nonunion, heat necrosis and avascular necrosis

Comparative study of titanium elastic nailing versus hip spica in treatment of femoral shaft fractures in children

Background: There is no consensus on treatment of closed femoral-shaft fractures in children. We compared hip spica cast with titanium elastic nailing (TEN) in the treatment of femoral-shaft fractures in children.Methods: Study was conducted at SMS Medical College, Jaipur (Rajasthan). Out of 90 Patients of diaphyseal fracture femur, 45were treated conservatively by spica cast and 45 were treated with TEN. Follow up done regularly up to twelve months of injury with taking into account, various parameters.Results: All diaphyseal fractures of femur healed, whether treated conservatively by spica cast or treated operatively with TEN. The time of union and weight bearing was less in operative group as comparative to spica cast group. Ten patients (22.22%) in spica group compared to three patients (6.66%) in operative group had malunion and two patients (4.4%) in spica group compared none in operative group had delayed union.Conclusions: Results of TEN turned out to be far superior to traction and spica cast treatment in paediatric femoral fractures. Rate of complications was far low with operative than conservative Treatment

Entropic Origin of the Growth of Relaxation Times in Simple Glassy Liquids

Transitions between ``glassy'' local minima of a model free-energy functional for a dense hard-sphere system are studied numerically using a ``microcanonical'' Monte Carlo method that enables us to obtain the transition probability as a function of the free energy and the Monte Carlo ``time''. The growth of the height of the effective free energy barrier with density is found to be consistent with a Vogel-Fulcher law. The dependence of the transition probability on time indicates that this growth is primarily due to entropic effects arising from the difficulty of finding low-free-energy saddle points connecting glassy minima.Comment: Four pages, plus three postscript figure

Wound Healing in Peripheral Arterial Disease: Current and Future Therapy

Wounds secondary to peripheral arterial disease (PAD) result in substantial morbidity and burden to the healthcare industry. To aid in the care of this patient population, knowledge of the disease process and current standards of therapy is paramount for healthcare providers.The future care of these patients and improvement from our existing standards hinges on the active translational research. To implement new technologies and advances in the treatment of PAD-induced wounds and ensure adequate utilization of our current therapies a PAD-wound team is necessary

Quaternary borocarbides: New class of intermetallic superconductors

Our recent discovery of superconductivity (SC) in the four-element multiphase Y-Ni-B-C system at an elevated temperature (TC approximately 12 K) has opened up great possibilities of identifying new superconducting materials and generating new physics. Superconductivity with Tc (greater than 20 K) higher than that known so far in bulk intermetallics has been observed in multiphase Y-Pd-B-C and Th-Pd-B-C systems and a family of single phase materials RENi2B2C (RE= Y, rare earth) have been found. Our investigations show YNi2B2C to be a strong coupling hard type-II SC. HC2(T) exhibits an unconventional temperature dependence. Specific heat and magnetization studies reveal coexistence of SC and magnetism in RNi2B2C (R = Ho, Er, Tm) with magnetic ordering temperatures (Tc approximately 8 K, 10.5 K, 11 K and Tm approximately 5 K, approximately 7K, approximately 4 K respectively) that are remarkably higher than those in known magnetic superconductors . Mu-SR studies suggest the possibility of Ni atoms carrying a moment in TmNi2B2C. Resistivity results suggests a double re-entrant transition (SC-normal-SC) in HoNi2B2C. RENi2B2C (RE = Ce, Nd, Gd) do not show SC down to 4.2 K. The Nd- and Gd-compounds order magnetically at approximately 4.5 K and approximately 19.5 K, respectively. Two SC transitions are observed in Y-Pd-B-C (Tc approximately 22 K, approximately 10 K) and in Th-Pd-B-C (Tc approximately 20 K, approximately 14 K) systems, which indicate that there are at least two structures which support SC in these borocarbides. In our multiphase ThNi2B2C we observe SC at approximately 6 K. No SC was seen in multiphase UNi2B2C, UPd2B2C, UOs2Ge2C and UPd5B3C(0.35) down to 4.2 K. Tc in YNi2B2C is depressed by substitutions (Gd, Th and U at Y-sites and Fe, Co at Ni-sites)

Extended Self-similarity in Kinetic Surface Roughening

We show from numerical simulations that a limited mobility solid-on-solid model of kinetically rough surface growth exhibits extended self-similarity analogous to that found in fluid turbulence. The range over which scale-independent power-law behavior is observed is significantly enhanced if two correlation functions of different order, such as those representing two different moments of the difference in height between two points, are plotted against each other. This behavior, found in both one and two dimensions, suggests that the `relative' exponents may be more fundamental than the `absolute' ones.Comment: 4 pages, 4 postscript figures included (some changes made according to referees' comments. accepted for publication in PRE Rapid Communication

Phase Diagram Of A Hard-sphere System In A Quenched Random Potential: A Numerical Study

We report numerical results for the phase diagram in the density-disorder plane of a hard sphere system in the presence of quenched, random, pinning disorder. Local minima of a discretized version of the Ramakrishnan-Yussouff free energy functional are located numerically and their relative stability is studied as a function of the density and the strength of disorder. Regions in the phase diagram corresponding to liquid, glassy and nearly crystalline states are mapped out, and the nature of the transitions is determined. The liquid to glass transition changes from first to second order as the strength of the disorder is increased. For weak disorder, the system undergoes a first order crystallization transition as the density is increased. Beyond a critical value of the disorder strength, this transition is replaced by a continuous glass transition. Our numerical results are compared with those of analytical work on the same system. Implications of our results for the field-temperature phase diagram of type-II superconductors are discussed.Comment: 14 pages, 10 postscript figures (included), submitted to Phys. Rev.