Vortex solutions of a Maxwell-Chern-Simons field coupled to four-fermion theory

We find the static vortex solutions of the model of Maxwell-Chern-Simons gauge field coupled to a (2+1)-dimensional four-fermion theory. Especially, we introduce two matter currents coupled to the gauge field minimally: the electromagnetic current and a topological current associated with the electromagnetic current. Unlike other Chern-Simons solitons the N-soliton solution of this theory has binding energy and the stability of the solutions is maintained by the charge conservation laws.Comment: 7 pages, harvmac, To be published in Phys. Rev. D5

Influence of oxygen vacancy on the electronic structure of HfO2_2 film

We investigated the unoccupied part of the electronic structure of the oxygen-deficient hafnium oxide (HfO$_{\sim1.8}$) using soft x-ray absorption spectroscopy at O $K$ and Hf $N_3$ edges. Band-tail states beneath the unoccupied Hf 5$d$ band are observed in the O $K$-edge spectra; combined with ultraviolet photoemission spectrum, this indicates the non-negligible occupation of Hf 5$d$ state. However, Hf $N_3$-edge magnetic circular dichroism spectrum reveals the absence of a long-range ferromagnetic spin order in the oxide. Thus the small amount of $d$ electron gained by the vacancy formation does not show inter-site correlation, contrary to a recent report [M. Venkatesan {\it et al.}, Nature {\bf 430}, 630 (2004)].Comment: 5 pages, 4 figures, submitted to Phys. Rev.

Synthesis of Cell-Adhesive Anisotropic Multifunctional Particles by Stop Flow Lithography and Streptavidin–Biotin Interactions

Cell-adhesive particles are of significant interest in biotechnology, the bioengineering of complex tissues, and biomedical research. Their applications range from platforms to increase the efficiency of anchorage-dependent cell culture to building blocks to loading cells in heterogeneous structures to clonal-population growth monitoring to cell sorting. Although useful, currently available cell-adhesive particles can accommodate only homogeneous cell culture. Here, we report the design of anisotropic hydrogel microparticles with tunable cell-adhesive regions as first step toward micropatterned cell cultures on particles. We employed stop flow lithography (SFL), the coupling reaction between amine and N-hydroxysuccinimide (NHS) and streptavidin–biotin chemistry to adjust the localization of conjugated collagen and poly-l-lysine on the surface of microscale particles. Using the new particles, we demonstrate the attachment and formation of tight junctions between brain endothelial cells. We also demonstrate the geometric patterning of breast cancer cells on particles with heterogeneous collagen coatings. This new approach avoids the exposure of cells to potentially toxic photoinitiators and ultraviolet light and decouples in time the microparticle synthesis and the cell culture steps to take advantage of the most recent advances in cell patterning available for traditional culture substrates.National Institutes of Health (U.S.) (GM092804)National Science Foundation (U.S.) (CMMI-1120724 and DMR-1006147)Samsung Scholarship Foundatio

Long-term sac behavior after endovascular abdominal aortic aneurysm repair with the Excluder low-permeability endoprosthesis

PurposeSac regression is a surrogate marker for clinical success in endovascular aneurysm repair (EVAR) and has been shown to be device-specific. The low porosity Excluder endograft (Excluder low-permeability endoprosthesis [ELPE]; W. L. Gore & Associates Inc, Flagstaff, Ariz) introduced in 2004 was reported in early follow-up to be associated with sac regression rates similar to other endografts, unlike the original Excluder which suffered from sac growth secondary to fluid accumulation in the sac. The purpose of this study was to determine whether this behavior is durable in mid-term to long-term follow-up.MethodsBetween July 2004 and December 2007, 301 patients underwent EVAR of an abdominal aortic aneurysm (AAA) with the ELPE at two institutions. Baseline sac size was measured by computed tomography (CT) scan at 1 month after repair. Follow-up beyond 1 year was either with a CT or ultrasound scan. Changes in sac size ≥5 mm from baseline were determined to be significant. Endoleak history was assessed with respect to sac behavior using χ2 and logistic regression analysis.ResultsTwo hundred sixteen patients (mean age 73.6 years and 76% men) had at least 1-year follow-up imaging available for analysis. Mean follow-up was 2.6 years (range, 1-5 years). The average minor-axis diameter was 52 mm at baseline. The proportion of patients with sac regression was similar during the study period: 58%, 66%, 60%, 59%, and 63% at 1 to 5 years, respectively. The proportion of patients with sac growth increased over time to 14.8% at 4-year follow-up. The probability of freedom from sac growth at 4 years was 82.4%. Eighty patients (37.7%) had an endoleak detected at some time during follow-up with 29.6% (16 of 54) residual endoleak rate at 4 years; 13 of the residual 16 endoleaks were type II. All patients with sac growth had endoleaks at some time during the study compared with only 18% of patients with sac regression (P < .0001).ConclusionA sustained sac regression after AAA exclusion with ELPE is noted up to 5-year follow-up. Sac enlargement was observed only in the setting of a current or previous endoleak, with no cases of suspected hygroma formation noted

Whole Genome Analysis of the Red-Crowned Crane Provides Insight into Avian Longevity

The red-crowned crane (Grus japonensis) is an endangered, large-bodied crane native to East Asia. It is a traditional symbol of longevity and its long lifespan has been confirmed both in captivity and in the wild. Lifespan in birds is known to be positively correlated with body size and negatively correlated with metabolic rate, though the genetic mechanisms for the red-crowned crane&apos;s long lifespan have not previously been investigated. Using whole genome sequencing and comparative evolutionary analyses against the grey-crowned crane and other avian genomes, including the long-lived common ostrich, we identified red-crowned crane candidate genes with known associations with longevity. Among these are positively selected genes in metabolism and immunity pathways (NDUFA5, NDUFA8, NUDT12, SOD3, CTH, RPA1, PHAX, HNMT, HS2ST1, PPCDC, PSTK CD8B, GP9, IL-9R, and PTPRC). Our analyses provide genetic evidence for low metabolic rate and longevity, accompanied by possible convergent adaptation signatures among distantly related large and long-lived birds. Finally, we identified low genetic diversity in the red-crowned crane, consistent with its listing as an endangered species, and this genome should provide a useful genetic resource for future conservation studies of this rare and iconic species

Electronic and Magnetic Properties of Electron-doped Superconductor, Sm_{1.85}Ce_{0.15}CuO_{4-delta}

Temperature-dependent magnetization (M(T)) and specific heat (C_p(T)) measurements were carried out on single crystal Sm_{1.85}Ce_{0.15}CuO_{4-delta} (T_c = 16.5 K). The magnetic anisotropy in the static susceptibility, chi {equiv} M/H, is apparent not only in its magnitude but also in its temperature dependence, with chi_{perp} for H{perp}c larger than chi_{parallel} for H{parallel}c. For both field orientations, chi does not follow the Curie-Weiss behavior due to the small energy gap of the J = 7/2 multiplet above the J = 5/2 ground-state multiplet. However, with increasing temperature, chi_{parallel}(T) exhibits a broad minimum near 100 K and then a slow increase while chi_{perp}(T) shows a monotonic decrease. A sharp peak in C_p(T) at 4.7 K manifests an antiferromagnetic ordering. The electronic contribution, gamma, to C_p(T) is estimated to be gamma = 103.2 (7) mJ/moleSmK^2. The entropy associated with the magnetic ordering is much smaller than Rln2, where R is the gas constant, which is usually expected for the doublet ground state of Sm^{+3}. The unusual magnetic and electronic properties evident in M(T) and C_p(T) are probably due to a strong anisotropic interaction between conduction electrons and localized electrons at Sm^{+3} sites.Comment: 5 pages, 5 encapsulated postscript figures, late

B -> Xs l_i^+ l_j^+ Decays with R-parity Violation

We derive the upper bounds on certain products of R-parity- and lepton-flavor-violating couplings from B \ra X_s {l_i}^+ {l_j}^- decays. These modes of B-meson decays can constrain the product combinations of the couplings with one or more heavy generation indices which are comparable with or stronger than the present bounds. From the studies of the invariant dilepton mass spectrum and the forward backward asymmetry of the emitted leptons we note the possibility of detecting R-parity-violating signals even when the total decay rate due to R-parity violating couplings is comparable with that in the standard model and discriminating two types of R-parity-violating signals. The general expectation of the enhancement of the forward backward asymmetry of the emitted leptons in the minimal supersymmetric standard model with R-parity may be corrupted by R-parity violation.Comment: 10 pages, Revtex, 1 table and 2 figure