1,597 research outputs found
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 plasmaâsample 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 jetâjet 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 100ÎŒs 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 jetâjet uniformity conditions for
O2/He = 0.3â0.7%. These results indicate the potential of 2D CAP jet arrays for uniform treatment and for effective control of jetâjet interactions. Furthermore,
spatial uniformity is accompanied by rich dynamics of jetâjet interactions and
jetâsample 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 jetâjet interactions
and plasmaâsurface 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: 10âyears' 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, Câreactive 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] 34.0â127.0) months. Median tSACT was 31.8 (IQR 12.0â76.3) months. On multivariate analysis, only CRP was predictive of tSACT (HR 2.47 [95% CI:1.59â3.85] p â10 mg/L were more likely to commence SACT within 1 year than those with CRPâ€10 mg/L (41% vs. 18%, Relative Risk 2.16 (95% CI:1.18â3.96) (p =â0.012)). 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 decisionâmaking 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 realâworld setting
Study of temperature dependent atomic correlations in MgB
We have studied the evolution with temperature of the local as well as the
average crystal structure of MgB 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 anharmonic phonons
Two-dimensional Transport Induced Linear Magneto-Resistance in Topological Insulator BiSe 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 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 ,
, are determined.Comment: Submitted to Phys. Rev. Let
Measurement of decays to baryon pairs
A sample of 3.95M decays registered in the BES detector are used
to study final states containing pairs of octet and decuplet baryons. We report
branching fractions for , ,
, ,
, ,
, and . These results
are compared to expectations based on the SU(3)-flavor symmetry, factorization,
and perturbative QCD.Comment: 22 pages, 21 figures, 4 table
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