Search

Funding Acknowledgements Type of funding sources: None. Background Visually guided laser balloon (VGLB) has proven ample efficacy in achieving durable pulmonary vein (PV) isolation (PVI). Though the isolation area post-cryoballoon ablation has been reported to regress at the chronic phase, the shrinkage of the isolation area using VGLB during the chronic phase has not been described. Purpose This study aims to evaluate the differences in isolation areas created by VGLB between the acute and chronic phases using a high-resolution mapping system. Methods We assessed 26 patients who underwent a second procedure due to atrial fibrillation recurrence. Of them, 8 patients were treated with the third-generation VGLB and 18 patients were treated with the first-generation VGLB at the first session. In all patients, the voltage maps were created with high-resolution mapping catheters just after PVI (acute phase) and during the second session (chronic phase). With each map, the isolation area ( Results The isolation areas were re-evaluated at 8.3±6.6 months after the initial procedure. Twenty patients (76.9%) preserved persistent isolation lesions of all four PVs. Of them, the reduction of the isolation areas on the left- and right-sided PV antrum were 1.6±3.2 cm² (10.7±23.1% of the acute phase) and 4.8±3.6 cm² (27.8±18.9%), respectively. The analysis of the results revealed that the isolation area of the right-sided PV antrum yielded statistical shrinkage during the chronic phase (P=0.001), even though the electrical isolation was preserved. Conclusion After VGLB ablation, the isolation area of the right-sided PV antrum significantly regressed at the chronic phase, while the rate of durable PVI was high in line with the previous report.

Monolayer transition metal dichalcogenides (TMDCs), like MoS

The exciton–polaritonic states are generated by the strong interaction between photons and excitons in confined nanocavities. To achieve strong coupling between excitons in TMDCs and optical modes ...

To understand the practical effects of pressure-transmitting media (PTM) on neutron diffraction using Paris–Edinburgh presses, diffraction patterns of MgO were collected to approximately 20 GPa using PTMs of Pb, AgCl, 4:1 methanol–ethanol (ME) mixture with and without heating, N2, and Ar. Hydrostaticity in the sample chamber estimated from the MgO 220 peak width improves in the order of Pb, AgCl, Ar, ME mixture, N2, and the heated ME mixture. Unlike previous results using diamond anvil cells, the unheated ME mixture is superior to Ar even after freezing, probably due to the cup on the anvil face. Considering these results and the sizable coherent scattering of Ne, which would show good hydrostaticity, we conclude that the ME mixture (preferably the heated one) is the best PTM in neutron experiments up to 20 GPa, while Ar can be substituted when a sample is reactive to alcohols.

Quasi one-dimensional semiconductor nanowires (NWs) in either arrays or single free-standing forms have shown unique optical properties (i.e., light absorption and emission) differently from their thin film or bulk counterparts, presenting new opportunities for achieving enhanced performance and/or functionalities for optoelectronic device applications. However, there is still a lack of understanding of the absorption properties of vertically standing single NWs within an array environment with light coupling from neighboring NWs within certain distances, due to the challenges in fabrication of such devices. In this article, we present a new approach to fabricate single vertically standing NW photodetectors from an ordered InP NW arrays using the focused ion beam technique, to allow direct measurements of optical and electrical properties of single NWs standing in an array. The light-matter interaction and photodetector performance are investigated using both experimental and theoretical methods. The consistent photocurrent and simulated absorption mapping results reveal that the light absorption and thus photoresponse of single NWs are strongly affected by the NW array geometry and related light coupling from their surrounding dielectric environment, due to the large absorption cross section and/or strong light interaction. While the highest light concentration factor (~ 19.64) was obtained from the NW in an array with a pitch of 1.5 µm, the higher responsivity per unit cell (equivalent to NW array responsivity) of a single standing NW photodetector was achieved in an array with a pitch of 0.8 µm, highlighting the importance of array design for practical applications. The insight from our study can provide important guidance to evaluate and optimize the device design of NW arrays for a wide range of optoelectronic device applications.

Monolayer transition metal dichalcogenides (TMDCs), like MoS$_2$, MoSe$_2$, WS$_2$, and WSe$_2$, feature direct bandgaps, strong spin-orbit coupling, and exciton-polariton interactions at the atomic scale, which could be harnessed for efficient light emission, valleytronics, and polaritonic lasing, respectively. Nevertheless, to build next-generation photonic devices that make use of these features, it is first essential to model the all-optical control mechanisms in TMDCs. Herein, a simple model is proposed to quantify the performance of a 35$\,$\textmu m long Si$_3$N$_4$ waveguide-integrated all-optical MoSe$_2$ modulator. Using this model, a switching energy of 14.6$\,$pJ is obtained for a transverse-magnetic (TM) and transverse-electric (TE) polarised pump signals at $\lambda =\,$480$\,$nm. Moreover, maximal extinction ratios of 20.6$\,$dB and 20.1$\,$dB are achieved for a TM and TE polarised probe signal at $\lambda =\,$500$\,$nm, respectively, with an ultra-low insertion loss of $, Comment: \copyright 2022 Optica Publishing Group. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited

The gas-phase etching of SiO2 was examined using HF and methanol vapor at temperatures below 0 °C and at low pressure. The etching rate of SiO2 increased with decreasing temperature and showed a maximum around –30 °C. The obtained etching rate was a maximum of 40 nm min−1 at plasma-enhanced chemical vapor deposition SiO2. The etching rate of SiN examined for comparison was more than ten times smaller than that of SiO2 under the same condition. As a result, the etching selectivity of SiO2 to SiN was found to be over 20 at –40 °C. When utilizing a low temperature of less than –30 °C, gas-phase etching of SiO2 showing a high etching rate and selectivity was achieved.

International audience; Carbon disulphide (CS2) is, together with its closest analogue CO2, one of the simplest molecular systems made of double covalent bonds. Under high pressure, the molecular structure is expected to break up to form extended crystalline or polymeric solids. Here we show that by compression at 300 K to ∼10 GPa (100 kbar) using large-volume high pressure techniques, a sudden reaction leads to a mixture of pure sulphur and a well-defined compound with stoichiometry close to C2S which can be recovered to ambient pressure. We present neutron and x-ray diffraction as well as Raman data which show that this material consists of sulphur bonded to sp2 graphite layers of nanometric dimensions. The compound is a semiconductor with a gap of 45 meV, as revealed by temperature dependent resistivity measurements, and annealing at temperatures above 200 °C allows to reduce its sulphur content up to C10S. Its structural and electronic properties are fundamentally different to “Bridgman black” reported from previous high pressure experiments on CS2.

We report the results of muon spin relaxation ($\ensuremath{\mu}\mathrm{SR}$) and $^{29}\mathrm{Si}$ NMR measurements carried out on the cubic chiral magnet EuPtSi. This compound exhibits a helimagnetic transition at ${T}_{\mathrm{N}}=4$ K, and hosts a unique skyrmion phase characterized by a short modulation period and strong anisotropy under magnetic fields. Our zero-field $\ensuremath{\mu}\mathrm{SR}$ experiments revealed the development of critical slowing down of Eu spin fluctuations over a relatively wide critical region $(T\ensuremath{-}{T}_{\mathrm{N}})/{T}_{\mathrm{N}}l5$ above ${T}_{\mathrm{N}}$. We also found from $^{29}\mathrm{Si}$ NMR that the spin fluctuations are strongly suppressed by magnetic field in the paramagnetic state above 20 K. These characteristic spin dynamics observed over a wide region of temperature and magnetic field suggest the presence of magnetic frustration in the spin system. Such frustration would underlie the mechanism stabilizing the short-period skyrmion lattice observed in this compound.

Paratrichaptum accuratum is a large conspicuous polypore fungus growing on dead or living angiosperm trees in subtropical-boreal areas of China, Indonesia, Japan, and Taiwan. The present study places P. accuratum in the family Gloeophyllaceae that belongs to the order Gloeophyllales within Agaricomycetes (Basidiomycota), based on evidence derived from morphological and ecological characteristics, and phylogenetic analyses of sequences of nuclear rDNA regions (5.8S, nuc 18S, nuc 28S) and protein-coding genes (rpb1, rpb2, and tef1). The analyses presented in this study also give strong support for including Jaapia in Gloeophyllaceae and Gloeophyllales. Thus, the names Jaapiaceae and Jaapiales are considered here as synonyms of Gloeophyllaceae and Gloeophyllales. Since Paratrichaptum represents the earliest diverging lineage in Gloeophyllales, pileate basidiocarps and brown rot appear to be ancestral states of Gloeophyllales. Paratrichaptum accuratum may represent a relic species, according to its phylogenetic position, peculiar distribution pattern and rare occurrence.

Nano-antennas are replicas of antennas that operate at radio-frequencies, but with considerably smaller dimensions when compared with their radio frequency counterparts. Noble metals based nano-antennas have the ability to enhance photoinduced phenomena such as localized electric fields, therefore-they have been used in various applications ranging from optical sensing and imaging to performance improvement of solar cells. However, such nano-structures can be damaged in high power applications such as heat resisted magnetic recording, solar thermo-photovoltaics and nano-scale heat transfer systems. Having a small footprint, nano-antennas cannot handle high fluences (energy density per unit area) and are subject to being damaged at adequately high power (some antennas can handle just a few milliwatts). In addition, given that nano-antennas are passive devices driven by external light sources, the potential damage of the antennas limits their use with high power lasers: this liability can be overcome by employing materials with high melting points such as chromium (Cr) and tungsten (W). In this article, we fabricate chromium and tungsten nano-antennas and demonstrate that they can handle 110 and 300 times higher fluence than that of gold (Au) counterpart, while the electric field enhancement is not significantly reduced.

A dissociative force field for all-atomistic molecular dynamics calculations has been developed to investigate impact fracture of polymers accompanying dissociation of chemical bonds of polymer main chain. Energy of dimer molecules was evaluated as a function of both bond-length b and bond-angle θ by CASPT2 calculations, whose quality is enough to describe dissociation of chemical bonds. Because we found that the bond dissociation energy D decreases with increasing bond-angle, we employed the Morse-type function VBond (b, θ) = {D - VAngle (θ)}[1 - exp{-α(b - b0 ) - β(b - b0 )2 }] where a quartic function VAngle (θ) = k1 (θ - θ0 ) + k2 (θ - θ0 )2 + k3 (θ - θ0 )3 + k4 (θ - θ0 )4 . This function reproduced well the CASPT2 potential energy surface in a wide range of b and θ. The parameters have been obtained for four popular glassy polymers, polyethylene, poly(methyl methacrylate), poly(styrene), and polycarbonate. © 2019 Wiley Periodicals, Inc.

In this paper, we analyze the performance of two tantalum-based boride (TaB and TaB2) microparticles as potential saturable absorbers for high-power fiber lasers. Both materials are ultrahigh temperature ceramics with melting points above 3000 °C, but with different crystalline structures: TaB has an orthorhombic structure (nearly isotropic), whereas TaB2 has a hexagonal structure (uniaxial, anisotropic). Despite their different crystalline structures, the microparticles have a similar low fluence attenuation (between 2.3 and 2.60 dB/μm) and modulation depths (around 2.0 dB/μm), but remarkable different saturation fluences: TaB has a saturation fluence of 160 μJ/cm2, whereas TaB2 has a saturation fluence of 110 μJ/cm2. The measured damage thresholds are 112 and 106 mJ/cm2/pulse for TaB and TaB2, respectively. When incorporated to a fiber laser, the materials produce pulses with durations of 345 ns, lower than those reported by our group in previous papers. The results show that the materials can find potential applications in high-power Q-switched lasers.

Hafnium diboride (HfB2) is used in hypervelocity re-entry vehicles (such as intercontinental ballistic missile (ICBM) or ICBM heat shields), nuclear reactors and aerodynamic leading edges because o...

The ultrafast response and broadband absorption of all-optical graphene switches are highly desirable features for on-chip photonic switching. However, because graphene is an atomically thin material, its absorption of guided optical modes is relatively low, resulting in high saturation thresholds and switching energies for these devices. To boost the absorption of graphene, we present a practical design of an electrically-biased all-optical graphene switch that is integrated into silicon slot waveguides, which strongly confine the optical mode in the slotted region and enhance its interaction with graphene. Moreover, the design incorporates a silicon slab layer and a hafnia dielectric layer to electrically tune the saturation threshold and the switching energy of the device by applying DC voltages of, Accepted for publication in the Journal of Optics

Fast detection of near-infrared (NIR) photons with high responsivity remains a challenge for photodetectors. Germanium (Ge) photodetectors are widely used for near-infrared wavelengths but suffer from a trade-off between the speed of photodetection and quantum efficiency (or responsivity). To realize a high-speed detector with high quantum efficiency, a small-sized photodetector efficiently absorbing light is required. In this paper, we suggest a realization of a dielectric metasurface made of an array of subwavelength germanium PIN photodetectors. Due to the subwavelength size of each pixel, a high-speed photodetector with a bandwidth of 65 GHz has been achieved. At the same time, high quantum efficiency for near-infrared illumination can be obtained by the engineering of optical resonant modes to localize optical energy inside the intrinsic Ge disks. Furthermore, small junction capacitance and the possibility of zero/low bias operation have been shown. Our results show that all-dielectric metasurfaces can improve the performance of photodetectors.

We investigated structural and magnetic properties of FeNi ordered alloy thin films grown by nitrogen-surfactant assisted process using scanning tunneling microscopy and soft-X-ray absorption spectroscopy/magnetic circular dichroism. With the help of structurally controlled surface and interface by the N surfactant effect, the results successfully provide the layer-resolved spin magnetic moments of the Fe layer. Furthermore, the critical role of the topmost layer on the magnetic anisotropy is identified from a thickness dependence of the Fe orbital magnetic moment; the out-of-plane magnetization emerges when the Fe–N bonds, which favor the in-plane magnetization, break and the Ni–N bonds form in the NiN topmost layer.

The strong light–matter interaction between the exciton of atomically thin transition metal dichalcogenides (TMDCs) and photonic nanocavities leads to the formation of unique hybrid light-matter quasiparticles known as exciton-polaritons. The newly formed mixed state has the advantages of the photonic part such as rapid propagation and low effective mass and the highly desirable optical properties of TMDC’s exciton, including the interparticle strong interactions nonlinearity and spin-valley polarization. These joint properties make such systems an ideal platform for studying many compelling physics phenomena and open the possibility of designing novel optoelectronic devices. This work reviews recent progress of strong coupling between exciton in TMDC and different resonant photonic structures, such as optical microcavities, plasmonic and all-dielectric nanocavities. Furthermore, we discussed the unique valleytronic and nonlinear properties of TMDC monolayers in the strong coupling regime. Finally, we highlighted some of the challenges and potential future research opportunities in this field.

Objective Melanocytes are widely distributed in the skin and often in oral mucosa but normally do not exist in bone tissue. The aim of this study was to compare the existence of melanocytes in odontogenic keratocysts (OKCs) and radicular cysts (RCs) and to clarify the difference in origin between those cysts. Methods One hundred and ten cases of OKCs and RCs were used. In OKC, 88 cases showed sporadic type (SPO), and 22 cases involved basal cell nevus syndrome (BCNS). OKC samples were divided into 54 cases in the juvenile group (0-29 years old) and 56 cases in the advanced group (30-70 years old). We researched these cysts with Melan-A and HMB45 immunohistochemical and Schmorl's reaction staining. Melanocytes were detected using Melan-A and HMB45 immunohistochemical stainings, and melanin pigmentation was detected using Schmorl's method. Results Melanocytes and melanin pigmentation were shown in OKC, and neither melanin pigmentation nor melanocytes existed in RC. The positive rate of Schmorl's reaction, Melan-A, and HMB45 staining were significantly higher in the juvenile group than in the advanced group. These rates were also higher in BCNS than in SPO. Conclusions Our data raise the important possibility that the origin of OKC epithelium differs from RC by the expression of melanocytes and melanin pigmentation. Our findings also underscore the fact that the origin of OKC differs between younger and older patients. It is suggested that melanin pigmentation and melanocytes expression may assist in the classification of odontogenic cysts in the future.