Extended Bose Hubbard model for two leg ladder systems in artificial magnetic fields

We investigate the ground state properties of ultracold atoms with long range interactions trapped in a two leg ladder configuration in the presence of an artificial magnetic field. Using a Gross-Pitaevskii approach and a mean field Gutzwiller variational method, we explore both the weakly interacting and strongly interacting regime, respectively. We calculate the boundaries between the density-wave/supersolid and the Mott-insulator/superfluid phases as a function of magnetic flux and uncover regions of supersolidity. The mean-field results are confirmed by numerical simulations using a cluster mean field approach.Comment: 11 pages, 11 figure

Anomalous pairing of bosons: Effect of multi body interactions in optical lattice

An interesting first order type phase transition between Mott lobes has been reported in Phys. Rev. Lett. 109, 135302 (2012) for a two-dimensional Bose-Hubbard model in the presence of attractive three-body interaction. We re-visit the scenario in a system of ultracold bosons in a one-dimensional optical lattice using the density matrix renormalization group method and show that an unconventional pairing of particles occurs due to the competing two-body repulsive and three-body attractive interactions. This leads to a pair superfluid phase sandwiched between the Mott insulator lobes corresponding to densities $\rho=1$ and $\rho=3$ in the strongly interacting regime. We further extend our analysis to a two dimensional Bose-Hubbard model using the self consistent cluster-mean-field theory approach and confirm that the unconventional pair superfluid phase stabilizes in the region between the Mott lobes in contrast to the direct first order jump as predicted before. In the end we establish connection to the most general Bose-Hubbard model and analyse the fate of the pair superfluid phase in presence of an external trapping potential.Comment: 5 pages, 6 figure

CALPASTATIN OVER-EXPRESSION REDUCES CARDIAC FIBROSIS IN A MURINE MODEL OF TYPE 2 DIABETES

Cardiovascular complications are the leading cause of diabetes-related morbidity and mortality. Calpain, a calcium-dependent protease, is increased in diabetic hearts yet its role in diabetic heart disease has not been demonstrated. We hypothesized that inhibition of calpain activity via calpastatin (CAST) over-expression will reduce the onset of myocardial fibrosis, a hallmark of diabetic cardiomyopathy, in the Type 2 murine model, db/db. Histological analysis together with gene expression measurements showed calpastatin over-expression reduced collagen content in db/db-CAST hearts. In order to understand the mechanisms responsible for this change, fibroblasts and known mediators of collagen synthesis and degradation were studied. Results indicated that calpain-induced derangements in MMP activity, stimulation of immune cells and up- regulation of cytokines responsible for promoting fibroblast differentiation and proliferation were reversed by calpastatin over-expression. This study shows that calpain inhibition is an effective means of decreasing collagen accumulation in the diabetic heart

Complete Traumatic Luxation of the Eyeball

Purpose: To report the computed tomography features of a case with complete luxation of the globe after a road traffic accident. Case Report: A 35-year-old male presented with pain, loss of vision, and bleeding from the left eye 48 hr after a road traffic accident. The ophthalmic examination of the left upper and lower eyelids showed edema with subcutaneous hematoma, crepitus, and complete blepharoptosis. On retracting the eyelids, the left eyeball was not visible and the patient was not able to perceive light. The left temporal region appeared filled with a soft, palpable globular structure situated beneath the temporalis muscle. A non-contrast computed tomography (NCCT) of the head and orbits showed a comminuted and displaced fracture of the floor, medial, and lateral orbital walls in addition to a displaced tripod fracture of the left zygomatic bone. The intact left eyeball was seen below the temporalis muscle without any optic nerve or extraocular muscle attachment. The virtual reality reconstruction highlighted a contributory supero-temporal defect in the bony orbit, which appeared large enough to accommodate the intact eyeball. Conclusion: The computed tomography of the orbits provided a detailed location of the luxated eyeball and provided guidance in further management of the case

Enhancement of QoS in 802.11e for Real Time Traffic

“Quality of Service (QoS) requirements like good throughput and minimum access delay are challenging tasks to accomplish with regard to 802.11 WLAN protocols and Medium Access Control (MAC) functions. In this article, a distributed medium access scheme called EDCF, which is adopted in an upcoming standard IEEE802.11e to allow prioritized medium access for applications with QoS requirements, is described and discussed. Its performance is also evaluated via simulations using network simulator called OPNET