Double resonance of Raman transitions in a degenerate Fermi gas

We measure momentum-resolved Raman spectra of a spin-polarized degenerate Fermi gas of $^{173}$Yb atoms for a wide range of magnetic fields, where the atoms are irradiated by a pair of counterpropagating Raman laser beams as in the conventional spin-orbit coupling scheme. Double resonance of first- and second-order Raman transitions occurs at a certain magnetic field and the spectrum exhibits a doublet splitting for high laser intensities. The measured spectral splitting is quantitatively accounted for by the Autler-Townes effect. We show that our measurement results are consistent with the spinful band structure of a Fermi gas in the spatially oscillating effective magnetic field generated by the Raman laser fields.Comment: 7 pages, 6 figure

The D0 same-charge dimuon asymmetry and possibile new CP violation sources in the Bs−BˉsB_s-\bar{B}_s system

Recently, the D0 collaboration reported a large CP violation in the same-sign dimuon charge asymmetry which has the $3.2 \sigma$ deviation from the value estimated in the Standard Model. In this paper, several new physics models are considered: the MSSM, two Higgs doublet model, the recent dodeca model, and a new $Z'$ model. Generally, it is hard to achieve such a large CP violation consistently with other experimental constraints. We find that a scheme with extra non-anomalous U(1)$'$ gauge symmetry is barely consistent. In general, the extra $Z'$ gauge boson induces the flavor changing neutral current interactions at tree level, which is the basic reason allowing a large new physics CP violation. To preserve the U(1)$'$ symmetry at high energy, SU(2)$_L$ singlet exotic heavy quarks of mass above 1 TeV and the Standard Model gauge singlet scalars are introduced.Comment: 12 pages, 13 figure

Micro-nano hybrid structures with manipulated wettability using a two-step silicon etching on a large area

Nanoscale surface manipulation technique to control the surface roughness and the wettability is a challenging field for performance enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that lead to maximizing of surface area, roughness, and wettability are developed for the boiling applications. MNHS structures consist of micropillars or microcavities along with nanowires having the length to diameter ratio of about 100:1. MNHS is fabricated by a two-step silicon etching process, which are dry etching for micropattern and electroless silicon wet etching for nanowire synthesis. The fabrication process is readily capable of producing MNHS covering a wafer-scale area. By controlling the removal of polymeric passivation layers deposited during silicon dry etching (Bosch process), we can control the geometries for the hierarchical structure with or without the thin hydrophobic barriers that affect surface wettability. MNHS without sidewalls exhibit superhydrophilic behavior with a contact angle under 10°, whereas those with sidewalls preserved by the passivation layer display more hydrophobic characteristics with a contact angle near 60°

Spontaneous generation and active manipulation of real-space optical vortex

Optical vortices host the orbital nature of photons, which offers an extra degree of freedom in photonic applications. Unlike vortices in other physical entities, optical vortices require structural singularities, which restrict their abilities in terms of dynamic and interactive characteristics. In this study, we present the spontaneous generation and external magnetic field-induced manipulation of an optical vortex and antivortex. A gradient-thickness optical cavity (GTOC) consisting of an Al/SiO2/Ni/SiO2 multilayer structure realised the distinct transition between the trivial and non-trivial topological phases, depending on the magneto-optic effects of the Ni layer. In the non-trivial topological phase, the mathematical singularities generating the optical vortex and antivortex pair in the reflected light existed in the generalised parameter space of the thicknesses of the top and bottom SiO2 layers, which is bijective to the real space of the GTOC. Coupled with the magnetisation, the optical vortex and antivortex in the GTOC experienced an effective spin-orbit interaction and showed topology-dependent dynamics under external magnetic fields. We expect that field-induced engineering of optical vortices will pave the way for the study of topological photonic interactions and their applications.Comment: 22 pages, 4 figure

Electron bunching from a dc-biased, single-surface multipactor with realistically broad energy spectrum and emission angle of secondary electrons

We studied the influences of wide energy spectrum and emission angle of secondary electrons on electron bunching from a dc-biased single surface multipactor. In our previous study of the same system, an ideally narrow energy spread of secondary electrons without emission angle was used in the analysis of the electron trajectory [M. S. Hur, J.-I. Kim, G.-J. Kim, and S.-G. Jeon, Phys. Plasmas 18, 033103 (2011) and S.-G. Jeon, J.-I. Kim, S.-T. Han, S.-S. Jung, and J. U. Kim, Phys. Plasmas 16, 073101 (2009)]. In this paper, we investigated the cases with realistic energy spectrum, which is featured by a wide energy spread and significant emission angle. To theoretically approach the matter of emission angle, we employed a concept of effective longitudinal velocity distribution. The theoretical results are verified by particle-in-cell (PIC) simulations. We also studied the electron bunching from a copper by PIC simulations, where we observed stable electron bunches with bunch width of approximately 80 mu m.open3

Detection of Biomolecular Binding Through Enhancement of Localized Surface Plasmon Resonance (LSPR) by Gold Nanoparticles

To amplify the difference in localized surface plasmon resonance (LSPR) spectra of gold nano-islands due to intermolecular binding events, gold nanoparticles were used. LSPR-based optical biosensors consisting of gold nano-islands were readily made on glass substrates using evaporation and heat treatment. Streptavidin (STA) and biotinylated bovine serum albumin (Bio-BSA) were chosen as the model receptor and the model analyte, respectively, to demonstrate the effectiveness of this detection method. Using this model system, we were able to enhance the sensitivity in monitoring the binding of Bio-BSA to gold nano-island surfaces functionalized with STA through the addition of gold nanoparticle-STA conjugates. In addition, SU-8 well chips with gold nano-island surfaces were fabricated through a conventional UV patterning method and were then utilized for image detection using the attenuated total reflection mode. These results suggest that the gold nano-island well chip may have the potential to be used for multiple and simultaneous detection of various bio-substances

Early Growth Response Factor-1 Is Associated With Intraluminal Thrombus Formation in Human Abdominal Aortic Aneurysm

ObjectivesThe goal of this study was to investigate the expression of early growth response-1 (Egr-1), a vascular pathogenic transcription factor, and its potential relationship with tissue factor (TF), a key player during the thrombus formation in the abdominal aortic aneurysm (AAA) wall.BackgroundAlthough intraluminal thrombus is a common finding in human AAA, the molecular mechanism of the thrombus formation has not been studied.MethodsDuring the elective AAA repair, specimens were taken from the thrombus-covered and thrombus-free portions of the aneurysmal wall in each of 16 patients with AAA and analyzed to assess the differential expression of Egr-1 and TF. The proinflammatory and prothrombogenic activities of Egr-1 in vasculature were evaluated in vitro and in vivo by overexpressing it using adenovirus.ResultsThe expression of both Egr-1 and TF was significantly increased in the thrombus-covered wall compared with the thrombus-free wall, in which their up-regulation in the thrombus-covered wall was strongly correlated with each other (p < 0.005, r = 0.717). Adenoviral overexpression of Egr-1 in human vascular smooth muscle and endothelial cells was found to up-regulate the expression of TF and inflammation-related genes. Moreover, Egr-1 overexpression in endothelial cells increased their adhesiveness to monocytes and also substantially promoted the intravascular thrombus formation in vivo, as shown in the inferior vena cava ligation experiment of the rat.ConclusionsThe present study demonstrates the differential up-regulation of Egr-1 in the thrombus-covered wall of human AAA and also suggests its possible contribution to the thrombogenic and inflammatory pathogenesis in human AAA

Pyoderma gangrenosum developed from aggravated pemphigus foliaceous after dog bite

Dear Editor, Pyoderma gangrenosum(PG) is a rare neutrophilic dermatosis that causes the development of painful ulcers on the skin, initially starting with nodules or abscesses, and quickly progressing at the peripheral regions into ulcers.1 The exact cause is not yet known, and 20-30% of patients are said to experience a pathergy phenomenon in which lesions occur in the sites of previous trauma.2 In addition, pyoderma gangrenosum is accompanied by systemic diseases, such as Crohn's disease or inflammatory colitis, rheumatoid arthritis, and hyperthyroidism.3 Although numerous reports indicate that pyoderma gangrenosum is associated with systemic diseases,4 case reports on the association of pyoderma gangrenosum with skin diseases, especially blistering disorders, are very rare. [...