Electron Beam Supercollimation in Graphene Superlattices

Although electrons and photons are intrinsically different, importing useful concepts in optics to electronics performing similar functions has been actively pursued over the last two decades. In particular, collimation of an electron beam is a long-standing goal. We show that ballistic propagation of an electron beam with virtual no spatial spreading or diffraction, without a waveguide or external magnetic field, can be achieved in graphene under an appropriate class of experimentally feasible one-dimensional external periodic potentials. The novel chiral quasi-one-dimensional metallic state that the charge carriers are in originates from a collapse of the intrinsic helical nature of the charge carriers in graphene owing to the superlattice potential. Beyond providing a new way to constructing chiral one-dimensional states in two dimensions, our findings should be useful in graphene-based electronic devices (e.g., for information processing) utilizing some of the highly developed concepts in optics.Comment: 7 pages, 4 figures (including supporting online material), published online in Nano Letter

New Generation of Massless Dirac Fermions in Graphene under External Periodic Potentials

We show that new massless Dirac fermions are generated when a slowly varying periodic potential is applied to graphene. These quasiparticles, generated near the supercell Brillouin zone boundaries with anisotropic group velocity, are different from the original massless Dirac fermions. The quasiparticle wavevector (measured from the new Dirac point), the generalized pseudospin vector, and the group velocity are not collinear. We further show that with an appropriate periodic potential of triangular symmetry, there exists an energy window over which the only available states are these quasiparticles, thus, providing a good system to probe experimentally the new massless Dirac fermions. The required parameters of external potentials are within the realm of laboratory conditions.Comment: 4 pages, 4 figure

Plasmacytoid Dendritic Cells Contribute to the Protective Immunity Induced by Intranasal Treatment with Fc-fused Interleukin-7 against Lethal Influenza Virus Infection

Developing a novel vaccine that can be applied against multiple strains of influenza virus is of utmost importance to human health. Previously, we demonstrated that the intranasal introduction of Fc-fused IL-7 (IL-7-mFc), a long-acting cytokine fusion protein, confers long-lasting prophylaxis against multiple strains of influenza A virus (IAV) by inducing the development of lung-resident memory-like T cells, called TRM-like cells. Here, we further investigated the mechanisms of IL-7-mFc-mediated protective immunity to IAVs. First, we found that IL-7-mFc treatment augments the accumulation of pulmonary T cells in 2 ways: recruiting blood circulating T cells into the lung and expanding T cells at the lung parenchyma. Second, the blockade of T cell migration from the lymph nodes (LNs) with FTY720 treatment was not required for mounting the protective immunity to IAV with IL-7-mFc, suggesting a more important role of IL-7 in T cells in the lungs. Third, IL-7-mFc treatment also recruited various innate immune cells into the lungs. Among these cells, plasmacytoid dendritic cells (pDCs) play an important role in IL-7-mFc-mediated protective immunity through reducing the immunopathology and increasing IAV-specific cytotoxic T lymphocyte (CTL) responses. In summary, our results show that intranasal treatment with IL-7-mFc modulates pulmonary immune responses to IAV, affecting both innate and adaptive immune cells. ? 2017. The Korean Association of Immunologists.112Ysciescopuskc

Long-Term Clinical Outcomes of Sirolimus- Versus Paclitaxel-Eluting Stents for Patients With Unprotected Left Main Coronary Artery Disease Analysis of the MAIN-COMPARE (Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty Versus Surgical Revascularization) Registry

ObjectivesThe aim of this study was to evaluate long-term clinical outcomes after implantation of sirolimus-eluting stents (SES) or paclitaxel-eluting stents (PES) among patients with unprotected left main coronary artery (LMCA) disease.BackgroundThere have been few comparisons of long-term outcomes among currently available drug-eluting stents (DES) for the treatment of LMCA disease.MethodsA total of 858 consecutive patients with unprotected LMCA stenosis were treated with SES (n = 669) or PES (n = 189) between May 2003 and June 2006. Primary outcome was the composite of death, myocardial infarction (MI), or target vessel revascularization (TVR).ResultsBaseline clinical and angiographic characteristics were similar in the 2 groups. During 3 years of follow-up, the adjusted risk of primary composite outcome was similar among the groups (SES vs. PES: 25.8% vs. 25.7%, hazard ratio [HR]: 0.95, 95% confidence interval [CI]: 0.64 to 1.41, p = 0.79). The 2 groups also showed a comparable adjusted rate of each component of outcome: death (9.1% vs. 11.0%, HR: 0.92, 95% CI: 0.47 to 1.80, p = 0.82), MI (8.1% vs. 8.0%, HR: 0.80, 95% CI: 0.43 to 1.48, p = 0.47), and TVR (12.1% vs. 10.6%, HR: 1.10, 95% CI: 0.53 to 2.29, p = 0.81). The 3-year rates of definite or probable stent thrombosis were 0.6% in the SES group and 1.6% in the PES group (adjusted p = 0.18).ConclusionsIn consecutive patients with unprotected LMCA disease undergoing DES implantation, SES and PES showed similar long-term clinical outcomes in terms of death, MI, repeat revascularization, and stent thrombosis

Incidence, Predictors, Treatment, and Long-Term Prognosis of Patients With Restenosis After Drug-Eluting Stent Implantation for Unprotected Left Main Coronary Artery Disease

ObjectivesThe aim of this study was to evaluate the incidence, predictors, and long-term outcomes of patients with in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) for unprotected left main coronary artery (LMCA) disease.BackgroundFew data on the clinical course and management of patients experiencing restenosis after DES treatment for unprotected LMCA disease have appeared.MethodsBetween February 2003 and November 2007, 509 consecutive patients with unprotected LMCA disease underwent DES implantation, with 402 (80.1%) undergoing routine surveillance or clinically driven angiographic follow-up. A major adverse cardiac event was defined as the composite of death, myocardial infarction (MI), or target-lesion revascularization.ResultsThe overall incidence of angiographic ISR in LMCA lesions was 17.6% (71 of 402 patients, 57 with focal-type and 14 with diffuse-type ISR. Forty patients (56.3%) underwent repeated PCI, 10 (14.1%) underwent bypass surgery, and 21 (29.6%) were treated medically. During long-term follow-up (a median of 31.7 months), there were no deaths, 1 (2.2%) MI, and 6 (9.5%) repeated target-lesion revascularization cases. The incidence of major adverse cardiac event was 14.4% in the medical group, 13.6% in the repeated PCI group, and 10.0% in the bypass surgery group (p = 0.91). Multivariate analysis showed that the occurrence of DES-ISR did not affect the risk of death or MI.ConclusionsThe incidence of ISR was 17.7% after DES stenting for LMCA. The long-term clinical prognosis of patients with DES-ISR associated with LMCA stenting might be benign, given that these patients were optimally treated with the clinical judgment of the treating physician