A two-dimensional cold atmospheric plasma jet array for uniform treatment of large-area surfaces for plasma medicine

For plasma treatment of inanimate surfaces and living tissues in medicine, it is important to control plasma–sample interactions and to mitigate non-uniform treatments of usually uneven sample surfaces so that effectiveness of application can be reproduced for different biological samples, relatively independently of their varying surface topologies and material characters. This paper reports a scalable two-dimensional (2D) array of seven cold atmospheric plasma (CAP) jets intended to achieve these two important requirements as well as to address the unique challenge of jet–jet interactions. While the CAP jet array can be configured to interact with a biological sample in either a direct mode (used with an in situ sample) or a remote mode (used as an afterglow), this study focuses on the direct mode. Using a downstream planar electrode as a sample model, the spatial distribution of reactive species and electrons delivered by individual jets of the 2D CAP jet array attains excellent uniformity. Specifically, the spatial variation over 100μs is 5.6 and 7.9%, respectively, for wavelength-integrated optical emission intensity, and for atomic oxygen emission intensity at 845 nm when the oxygen admixture is 0.5% of the helium carrier gas. It is also shown that the highest emission intensity at 845 nm occurs at O2/He = 0.5% under the best jet–jet uniformity conditions for O2/He = 0.3–0.7%. These results indicate the potential of 2D CAP jet arrays for uniform treatment and for effective control of jet–jet interactions. Furthermore, spatial uniformity is accompanied by rich dynamics of jet–jet interactions and jet–sample interactions. Of the honeycomb-arranged seven CAP jets, the central jet is strongest in the negative half cycle, whereas the six surrounding jets (of uniform strength) are strongest in the positive half cycle. These dynamic features offer possible insights with which to better control jet–jet interactions and plasma–surface interactions in future

Self-organized pattern formation of an atmospheric pressure plasma jet in a dielectric barrier discharge configuration

This letter reports the observation of self-organized patterns formed in a 29 mm wide atmospheric pressure plasma jet. By altering the gas flow rate and/or the applied voltage, the plasma jet is seen to have at least three different modes, namely, a diffuse-looking discharge, a self-organized discharge, and an unstable discharge with randomly occurring plasma channels. The self-organized discharge mode is characterized by several bright plasma channels embedded in a diffuse and dim plasma background. These plasma channels are regularly spaced from each other and their self-organized patterns are shown to evolve abruptly

Initial active surveillance for patients with metastatic renal cell carcinoma: 10 years' experience at a regional cancer Centre

Abstract A subset of patients with metastatic renal cell carcinoma (mRCC) follow an indolent disease course and may benefit from initial active surveillance (AS). However, selecting patients suitable for this approach is challenging. To investigate this we sought to define outcomes of patients with mRCC suitable for initial AS. All patients with mRCC clinically selected for initial AS at the Edinburgh Cancer Centre between January 2010 and December 2020 were identified. Key inflammatory biomarkers (haemoglobin, white cell count, neutrophil count, platelets, C‐reactive protein [CRP], albumin, corrected calcium) and the International Metastatic RCC Database Consortium (IMDC) risk score were measured. The relationship between these and time to systemic anticancer therapy (tSACT) and overall survival (OS) was analysed. Data were available for 160 patients. Estimated median overall survival was 88.0 (interquartile range [IQR] 34.0–127.0) months. Median tSACT was 31.8 (IQR 12.0–76.3) months. On multivariate analysis, only CRP was predictive of tSACT (HR 2.47 [95% CI:1.59–3.85] p  10 mg/L were more likely to commence SACT within 1 year than those with CRP≤10 mg/L (41% vs. 18%, Relative Risk 2.16 (95% CI:1.18–3.96) (p = 0.012)). IMDC risk score was not predictive of tSACT or OS. Active surveillance is an appropriate initial management option for selected patients with mRCC. CRP, a biomarker of systemic inflammation, may provide additional objective information to assist clinical decision‐making in patients with mRCC being considered for initial AS. Although this is a retrospective observational study, the cohort is well defined and includes all patients managed with initial AS in an inclusive real‐world setting

Study of temperature dependent atomic correlations in MgB2_{2}

We have studied the evolution with temperature of the local as well as the average crystal structure of MgB$_2$ using the real-space atomic pair distribution function (PDF) measured by high resolution neutron powder diffraction. We have investigated the correlations of the B-B and B-Mg nearest neighbor pair motion by comparing, in the wide temperature range from T=10 K up to T=600 K, the mean-square displacements (MSD) of single atoms with the mean-square relative displacements (MSRD) obtained from the PDF peak linewidths. The results show that the single atom B and Mg vibrations are mostly decoupled from each other, with a small predominance of positive (in phase) correlation factor for both the B-B and B-Mg pairs. The small positive correlation is almost temperature independent, in contrast with our theoretical calculations; this can be a direct consequence of the strong decay processes of the $E_{2g}$ anharmonic phonons

Two-dimensional Transport Induced Linear Magneto-Resistance in Topological Insulator Bi2_2Se3_3 Nanoribbons

We report the study of a novel linear magneto-resistance (MR) under perpendicular magnetic fields in Bi2Se3 nanoribbons. Through angular dependence magneto-transport experiments, we show that this linear MR is purely due to two-dimensional (2D) transport, in agreement with the recently discovered linear MR from 2D topological surface state in bulk Bi2Te3, and the linear MR of other gapless semiconductors and graphene. We further show that the linear MR of Bi2Se3 nanoribbons persists to room temperature, underscoring the potential of exploiting topological insulator nanomaterials for room temperature magneto-electronic applications.Comment: ACS Nano, in pres

Self-organized pattern formation of an atmospheric pressure plasma jet in a dielectric barrier discharge configuration

Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the authors and the American Institute of Physics. This article appeared in the journal, Applied Physics Letters, and may be found at: http://link.aip.org/link/?APPLAB/90/221504/1This letter reports the observation of self-organized patterns formed in a 29 mm wide atmospheric pressure plasma jet. By altering the gas flow rate and/or the applied voltage, the plasma jet is seen to have at least three different modes, namely, a diffuse-looking discharge, a self-organized discharge, and an unstable discharge with randomly occurring plasma channels. The self-organized discharge mode is characterized by several bright plasma channels embedded in a diffuse and dim plasma background. These plasma channels are regularly spaced from each other and their self-organized patterns are shown to evolve abruptly

CANDELS: Correlations of SEDs and Morphologies with Star-formation Status for Massive Galaxies at z ~ 2

We present a study on Spectral Energy Distributions, Morphologies, and star formation for an IRAC-selected extremely red object sample in the GOODS Chandra Deep Field-South. This work was enabled by new HST/WFC3 near-IR imaging from the CANDELS survey as well as the deepest available X-ray data from Chandra 4 Ms observations. This sample consists of 133 objects with the 3.6um limiting magnitude of [3.6] = 21.5, and is approximately complete for galaxies with M >10^{11}M_sun at 1.5 < z < 2.5. We classify this sample into two types, quiescent and star-forming galaxies, in the observed infrared color-color ([3.6]-[24] vs K-[3.6]) diagram. The further morphological study of this sample show a consistent result with the observed color classification. The classified quiescent galaxies are bulge dominated and star-forming galaxies in the sample have disk or irregular morphologies. Our observed infrared color classification is also consistent with the rest-frame color (U-V vs V-J) classification. We also found that quiescent and star-forming galaxies are well separated in the nonparametric morphology parameter (Gini vs M_{20}) diagram measuring their concentration and clumpiness: quiescent galaxies have Gini coefficient higher than 0.58 and star forming galaxies have Gini coefficient lower that 0.58. We argue that the star formation quenching process must lead to or be accompanied by the increasing galaxy concentration. One prominent morphological feature of this sample is that disks are commonly seen in this massive galaxy sample at 1.5 < z < 2.5: 30% of quiescent galaxies and 70% of star forming galaxies with M >10^{11}M_sun have disks in their rest-frame optical morphologies. The prevalence of these extended, relatively undisturbed disks challenges the merging scenario as the main mode of massive galaxy formation.Comment: 36 pages,16 figures,Accepted by Ap

Electrical generation and absorption of phonons in carbon nanotubes

The interplay between discrete vibrational and electronic degrees of freedom directly influences the chemical and physical properties of molecular systems. This coupling is typically studied through optical methods such as fluorescence, absorption, and Raman spectroscopy. Molecular electronic devices provide new opportunities for exploring vibration-electronic interactions at the single molecule level. For example, electrons injected from a scanning tunneling microscope tip into a metal can excite vibrational excitations of a molecule in the gap between tip and metal. Here we show how current directly injected into a freely suspended individual single-wall carbon nanotube can be used to excite, detect, and control a specific vibrational mode of the molecule. Electrons inelastically tunneling into the nanotube cause a non-equilibrium occupation of the radial breathing mode, leading to both stimulated emission and absorption of phonons by successive electron tunneling events. We exploit this effect to measure a phonon lifetime on the order of 10 nanoseconds, corresponding to a quality factor well over 10000 for this nanomechanical oscillator.Comment: 17 pages, 4 figure

Measurement of the Total Cross Section for Hadronic Production by e+e- Annihilation at Energies between 2.6-5 Gev

Using the upgraded Beijing Spectrometer (BESII), we have measured the total cross section for $e^+e^-$ annihilation into hadronic final states at center-of-mass energies of 2.6, 3.2, 3.4, 3.55, 4.6 and 5.0 GeV. Values of $R$, $\sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-)$, are determined.Comment: Submitted to Phys. Rev. Let

Measurements of the Cross Section for e+e- -> hadrons at Center-of-Mass Energies from 2 to 5 GeV

We report values of $R = \sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-)$ for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.Comment: 5 pages, 3 figure