Total synthesis of the putative structure of the novel triquinane natural product isocapnellenone

A total synthesis of the 'putative structure' 7, attributed to the novel triquinane sesquiterpene isolated recently from two Buddelia species has been accomplished. The spectral data for 7 is a complete mismatch with those reported for the natural product and warrants a revision of the assigned structure

SURGICAL MANAGEMENT OF FRACTURE BOTH BONES FOREARM WITH LOCKING COMPRESSION PLATE IN ADULT PATIENTS

Objective: The objective of this study was to assess the time taken for surgery, tourniquet time, and clinical outcome in diaphyseal fractures of both forearms managed with locking compression plate (LCP). Methods: Patients underwent open reduction and internal fixation with 3.5-mm LCP. Proximal radius was approached by dorsal Thompson incision and middle and distal radius by volar henry approach. A minimum of 6 cortices were engaged with screw fixation in each fragment. Ulna was approached directly over the subcutaneous border. Results: Of 20 patients, 70% were men; fracture was the most common in second and third decades of life. Road traffic accident (50%) and fall (40%) were the main causes. Fractures at mid-diaphysis (70%) and transverse/short oblique (72.5%) were the most common. Closed head injury, unilateral pubic bone fracture, olecranon fracture, fracture of both bones of leg, and ipsilateral fracture shaft humerus were the associated injuries. There was no intraoperative complication. Superficial infection (n=01) and transient posterior interosseous nerve injury, in the immediate postoperative period (n=01), were the reported complications. Average time for surgery was 77 min (60–90 min) and that for tourniquet was 54 min (40–60 min). All had complete union in <6 months; 80% had healing in <4 months. 20% healed in 4–6 months. Excellent and satisfactory results were seen in 85% and 15% patients, respectively. Conclusion: The 3.5-mm LCP, when applied properly, yields excellent outcome in fractures of forearm bones. The use of tourniquet, separate incisions for radius and ulna, and preservation of the natural curves of radius will reduce complications. Clinical outcome in terms of healing and union is excellent

Critical Crossover Between Yosida-Kondo Dominant Regime and Magnetic Frustration Dominant Regime in the System of a Magnetic Trimer on a Metal Surface

Quantum Monte Carlo simulations were carried out for the system of a magnetic trimer on a metal surface. The magnetic trimer is arranged in two geometric configurations, viz., isosceles and equilateral triangles. The calculated spectral density and magnetic susceptibility show the existence of two phases: Yosida-Kondo dominant phase and magnetic frustration dominant phase. Furthermore, a critical transition between these two phases can be induced by changing the configuration of the magnetic trimers from isosceles to equilateral triangle.Comment: 8 pages, 4 figures; accepted for publication in J. Phys. Soc. Jp

Kondo Effect in Fermi Systems with a Gap: A Renormalization Group Study

We present the results of a Wilson Renormalization Group study of the single-impurity Kondo and Anderson models in a system with a gap in the conduction electron spectrum. The behavior of the impurity susceptibility and the zero-frequency response function, $T>$ are discussed in the cases with and without particle-hole symmetry. In addition, for the asymmetric Anderson model the correlation functions, $<\vec S \cdot\vec \sigma (0)>$,$$, and$$ are computed.Comment: 10 pages, 10 figure

Numerical renormalization group study of the symmetric Anderson-Holstein model: phonon and electron spectral functions

We study the symmetric Anderson-Holstein (AH) model at zero temperature with Wilson's numerical renormalization group (NRG) technique to study the interplay between the electron-electron and electron-phonon interactions. An improved method for calculating the phonon propagator using the NRG technique is presented, which turns out to be more accurate and reliable than the previous works in that it calculates the phonon renormalization explicitly and satisfies the boson sum rule better. The method is applied to calculate the renormalized phonon propagators along with the electron propagators as the onsite Coulomb repulsion $U$ and electron-phonon coupling constant $g$ are varied. As $g$ is increased, the phonon mode is successively renormalized, and for $g \gtrsim g_{co}$ crosses over to the regime where the mode splits into two components, one of which approaches back to the bare frequency and the other develops into a soft mode. The initial renormalization of the phonon mode, as $g$ is increased from 0, depends on $U$ and the hybridization $\Delta$; it gets softened (hardened) for $U \gtrsim (\lesssim) U_s (\Delta)$. Correlated with the emergence of the soft mode is the central peak of the electron spectral function severely suppressed. These NRG calculations will be compared with the standard Green's function results for the weak coupling regime to understand the phonon renormalization and soft mode.Comment: 18 pages, 4 figures. Submitted to Phys. Rev.

Sticky Spheres, Entropy barriers and Non-equilibrium phase transitions

A sticky spheres model to describe slow dynamics of a non-equilibrium system is proposed. The dynamical slowing down is due to the presence of entropy barriers. We present an exact mean field analysis of the model and demonstrate that there is a non-equilibrium phase transition from an exponential cluster size distribution to a powerlaw.Comment: 10pages text and 2 figure