Graphene coatings: An efficient protection from oxidation

We demonstrate that graphene coating can provide an efficient protection from oxidation by posing a high energy barrier to the path of oxygen atom, which could have penetrated from the top of graphene to the reactive surface underneath. Graphene bilayer, which blocks the diffusion of oxygen with a relatively higher energy barrier provides even better protection from oxidation. While an oxygen molecule is weakly bound to bare graphene surface and hence becomes rather inactive, it can easily dissociates into two oxygen atoms adsorbed to low coordinated carbon atoms at the edges of a vacancy. For these oxygen atoms the oxidation barrier is reduced and hence the protection from oxidation provided by graphene coatings is weakened. Our predictions obtained from the state of the art first-principles calculations of electronic structure, phonon density of states and reaction path will unravel how a graphene can be used as a corrosion resistant coating and guide further studies aiming at developing more efficient nanocoatings.Comment: under review in PRB; http://link.aps.org/doi/10.1103/PhysRevB.85.15544

Resonant production of diquarks at high energy pp, ep and e+e- colliders

Resonant productions of the first generation scalar and vector diquarks at high energy hadron-hadron (pp), lepton-hadron (ep) and lepton-lepton (e+e-) colliders are investigated. Taking into account the hadronic component of the photon, diquarks can be produced resonantly in the lepton-hadron and lepton-lepton collisions. Production rates, decay widths and signatures of diquarks are discussed using the general, SU(3)_{C} x SU(2)_{W} x U(1)_{Y} invariant, effective Lagrangian. The corresponding dijet backgrounds are examined in the interested invariant mass regions. The attainable mass limits and couplings are obtained for the diquarks that can be produced in hadron collisions and in resolved photon processes. It is shown that hadron collider with center of mass energy sqrt(s)=14 TeV will be able to discover scalar and vector diquarks with masses up to m_{DQ}=9 TeV for quark-diquark-quark coupling alpha_{DQ}=0.1. Relatively, lighter diquarks can be probed at ep and e+e- collisions in more clear environment.Comment: 12 pages, 12 figures, 6 table

Adsorption and absorption of Boron, Nitrogen, Aluminium and Phosphorus on Silicene: stability, electronic and phonon properties

Ab initio calculations within the density-functional theory formalism are performed to investigate the chemical functionalization of a graphene-like monolayer of silicon - silicene - with B, N, Al or P atoms. The structural, electronic, magnetic and vibrational properties are reported. The most preferable adsorption sites are found to be valley, bridge, valley and hill site for B, N, Al and P adatoms, respectively. All the relaxed systems with adsorbed/substituted atoms exhibit metallic behaviour with strongly bonded B, N, Al, and P atoms accompanied by an appreciable electron transfer from silicene to the B, N and P adatom/substituent. The Al atoms exhibit opposite charge transfer, with n-type doping of silicene and weaker bonding. The adatoms/substituents induce characteristic branches in the phonon spectrum of silicene, which can be probed by Raman measurements. Using molecular dynamics we found that the systems under study are stable up to at least T = 500 K. Our results demonstrate that silicene has a very reactive and functionalizable surface.Comment: 9 pages, 5 figure

The effect of electromagnetic properties of neutrinos on the photon-neutrino decoupling temperature

We examine the impact of electromagnetic properties of neutrinos on the annihilation of relic neutrinos with ultra high energy cosmic neutrinos for the $\nu \bar{\nu}\to \gamma\gamma$ process. For this process, photon-neutrino decoupling temperature is calculated via effective lagrangian model beyond the standard model. We find that photon-neutrino decoupling temperature can be importantly reduced below the QCD phase transition with the model independent analysis defining electromagnetic properties of neutrinos.Comment: 12 pages, 3 figures, published versio

Unparticle Physics in the Moller Scattering

We investigate the virtual effects of vector unparticles in the Moller scattering. We derive the analytic expression for scattering amplitudes with unpolarized beams. We obtain 95% confidence level limits on the unparticle couplings $\lambda_{V}$ and $\lambda_{A}$ with integrated luminosity of $L_{int}=50, 500 fb^{-1}$ and $\sqrt{s}=100, 300$ and 500 GeV energies. We show that limits on $\lambda_{V}$ are more sensitive than $\lambda_{A}$.Comment: 10 pages, 5 figures, 4 table

An elementary optical gate for expanding entanglement web

We introduce an elementary optical gate for expanding polarization entangled W states, in which every pair of photons are entangled alike. The gate is composed of a pair of 50:50 beamsplitters and ancillary photons in the two-photon Fock state. By seeding one of the photons in an $n$-photon W state into this gate, we obtain an $(n+2)$-photon W state after post-selection. This gate gives a better efficiency and a simpler implementation than previous proposals for $\rm W$-state preparation.Comment: 5 pages, 2 figures. To appear in Phys. Rev.

Demonstration of local expansion toward large-scale entangled webs

We demonstrate an optical gate that increases the size of polarization-based W states by accessing only one of the qubits. Using this gate, we have generated three-photon and four-photon W states with fidelities $0.836\pm 0.042$ and $0.784\pm 0.028$, respectively. We also confirmed existence of pairwise entanglement in every pair of the qubits including the one that was left untouched by the gate. The gate is applicable to any size of W states and hence is a universal tool for expanding entanglement.Comment: 5 pages, 4 figure

COVID-19 Pandemi Sırasındaki Acil Cerrahi Bakım ve Ameliyathane Uygulamalarında Perioperatif Uygulama ve Rehberlik; Deneyimlerimiz

Aim: The novel coronavirus SARS-CoV-2 (COVID-19) can infect healthcare workers. We developed an institutional algorithm to protect operating room team members during the COVID-19 pandemic and rationally conserve personal protective equipment (PPE). We aimed to review the latest data on the COVID-19 pandemic and essential information for practice in emergency surgery and the operating room.Materials and Methods: An interventional platform (operating room, interventional suite, and endoscopy) with our committee formed with our doctors consisting of different branches, we developed our guidelines based on potential patterns of spread, risk of exposure, and conservation of PPE. We aimed to share our experiences with 128 patients who were taken into operation in a 2-month period.Anesthetic management and infection control guidelines for emergency procedures for patients with suspected 2019-nCoV were drafted and applied in Medical Faculty of Namık Kemal University.Results: A decision tree algorithm describing our institutional guidelines for precautions for operating room team members was created. This algorithm is based on the urgency of operation, anticipated viral burden at the surgical site, the opportunity for a procedure to aerosolize virus, and the likelihood a patient could be infected based on symptoms and testing.Conclusion: Despite COVID-19 being a new threat, we have shown that by developing an easy-to-follow decision algorithm for the interventional platform teams, we can ensure optimal healthcare worker safety.Amaç: Yeni koronavirüs SARS-CoV-2 (COVID-19) sağlık çalışanlarını enfekte edebilir. COVID-19 salgını sırasında ameliyathane ekip üyelerini korumak ve rasyonel olarak kişisel koruyucu ekipman (KKE) için kurumsal bir algoritma geliştirdik. Acil cerrahi ve ameliyathanede COVID-19 salgını ile ilgili en güncel bilgileri gözden geçirmeyi amaçladık. Materyal ve Metot: Farklı branşlardan oluşan doktorlarımızla oluşturduğumuz komitemiz ile girişimsel bir platform (ameliyathane, girişimsel ve endoskopi), potansiyel yayılma örüntüleri, maruz kalma riski ve KKE'nin korunmasına dayanan kılavuzlarımızı geliştirdik. Deneyimlerimizi 2 aylık bir sürede ameliyat edilen 128 hasta ile paylaşmayı amaçladık. 2019-nCoV şüphesi olan hastalar için acil durum prosedürleri için anestezi yönetimi ve enfeksiyon kontrol kılavuzları Namık Kemal Üniversitesi Tıp Fakültesi'nde hazırlanmış ve uygulanmıştır. Bulgular: Ameliyathane ekibi üyelerine yönelik önlemler için kurumsal yönergelerimizi açıklayan bir karar algoritması oluşturuldu. Bu algoritma ameliyatın aciliyetine, cerrahi bölgede beklenen viral yüke, virüsü aerosol haline getirme prosedürü fırsatına ve hastanın semptomlara ve testlere dayanarak enfekte olma olasılığına dayanır. Sonuç: COVID-19'un yeni bir tehdit olmasına rağmen, girişimsel platform ekipleri için izlemesi kolay bir karar algoritması geliştirerek, optimum sağlık çalışanı güvenliğini sağlayabildiğimizi gösterdik