578 research outputs found
Tailoring of the photocatalytic activity of CeO2 nanoparticles by the presence of plasmonic Ag nanoparticles
Altres ajuts: ICN2 is funded by the CERCA Programme/Generalitat de Catalunya.The present study investigates basic features of a photoelectrochemical system based on CeO nanoparticles fixed on gold electrodes. Since photocurrent generation is limited to the absorption range of the CeO in the UV range, the combination with metal nanoparticles has been studied. It can be shown that the combination of silver nanoparticles with the CeO can shift the excitation range into the visible light wavelength range. Here a close contact between both components has been found to be essential and thus, hybrid CeO@Ag nanoparticles have been prepared and analyzed. We have collected arguments that electron transfer occurs between both compositional elements of the hybrid nanoparticles.The photocurrent generation can be rationalized on the basis of an energy diagram underlying the necessity of surface plasmon excitation in the metal nanoparticles, which is also supported by wavelength-dependent photocurrent measurements. However, electrochemical reactions seem to occur at the CeO surface and consequently, the catalytic properties of this material can be exploited as exemplified with the photoelectrochemical reduction of hydrogen peroxide. It can be further demonstrated that the layer-by layer technique can be exploited to create a multilayer system on top of a gold electrode which allows the adjustment of the sensitivity of the photoelectrochemical system. Thus, with a 5-layer electrode with hybrid CeO@Ag nanoparticles submicromolar hydrogen peroxide concentrations can be detected
Tailoring of the photocatalytic activity of CeO2 nanoparticles by the presence of plasmonic Ag nanoparticles
Photocatalytic activity; NanoparticlesActividad fotocatalÃtica; NanopartÃculasActivitat fotocatalÃtica; NanopartÃculesThe present study investigates basic features of a photoelectrochemical system based on CeO2 nanoparticles fixed on gold electrodes. Since photocurrent generation is limited to the absorption range of the CeO2 in the UV range, the combination with metal nanoparticles has been studied. It can be shown that the combination of silver nanoparticles with the CeO2 can shift the excitation range into the visible light wavelength range. Here a close contact between both components has been found to be essential and thus, hybrid CeO2@Ag nanoparticles have been prepared and analyzed. We have collected arguments that electron transfer occurs between both compositional elements of the hybrid nanoparticles.The photocurrent generation can be rationalized on the basis of an energy diagram underlying the necessity of surface plasmon excitation in the metal nanoparticles, which is also supported by wavelength-dependent photocurrent measurements. However, electrochemical reactions seem to occur at the CeO2 surface and consequently, the catalytic properties of this material can be exploited as exemplified with the photoelectrochemical reduction of hydrogen peroxide. It can be further demonstrated that the layer-by layer technique can be exploited to create a multilayer system on top of a gold electrode which allows the adjustment of the sensitivity of the photoelectrochemical system. Thus, with a 5-layer electrode with hybrid CeO2@Ag nanoparticles submicromolar hydrogen peroxide concentrations can be detected.This work was supported by the Cluster of Excellence ‘Advanced Imaging of Matter’ of the Deutsche Forschungsgemeinschaft (DFG) – EXC 2056 – project ID 390715994. SZ acknowledges funding by the Chinese Scholarship Council (CSC). NGB and VP acknowledge financial support from the Spanish Ministerio de Ciencia, Innovación y Universidades (MCIU) (RTI2018-099965-B-I00, AEI/FEDER, UE). ICN2 is supported by the Severo Ochoa program from Spanish MINECO (SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. ZY acknowledges support from the National Natural Science Foundation of China (Grant No. 61871240)
Andreev Reflection without Fermi surface alignment in High T-Topological heterostructures
We address the controversy over the proximity effect between topological
materials and high T superconductors. Junctions are produced between
BiSrCaCuO and materials with different Fermi
surfaces (BiTe \& graphite). Both cases reveal tunneling spectra
consistent with Andreev reflection. This is confirmed by magnetic field that
shifts features via the Doppler effect. This is modeled with a single parameter
that accounts for tunneling into a screening supercurrent. Thus the tunneling
involves Cooper pairs crossing the heterostructure, showing the Fermi surface
mis-match does not hinder the ability to form transparent interfaces, which is
accounted for by the extended Brillouin zone and different lattice symmetries
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Androgen receptor as a mediator and biomarker of radioresistance in triple-negative breast cancer.
Increased rates of locoregional recurrence have been observed in triple-negative breast cancer despite chemotherapy and radiation therapy. Thus, approaches that combine therapies for radiosensitization in triple-negative breast cancer are critically needed. We characterized the radiation therapy response of 21 breast cancer cell lines and paired this radiation response data with high-throughput drug screen data to identify androgen receptor as a top target for radiosensitization. Our radiosensitizer screen nominated bicalutamide as the drug most effective in treating radiation therapy-resistant breast cancer cell lines. We subsequently evaluated the expression of androgen receptor in >2100 human breast tumor samples and 51 breast cancer cell lines and found significant heterogeneity in androgen receptor expression with enrichment at the protein and RNA level in triple-negative breast cancer. There was a strong correlation between androgen receptor RNA and protein expression across all breast cancer subtypes (R2 = 0.72, p < 0.01). In patients with triple-negative breast cancer, expression of androgen receptor above the median was associated with increased risk of locoregional recurrence after radiation therapy (hazard ratio for locoregional recurrence 2.9-3.2)) in two independent data sets, but there was no difference in locoregional recurrence in triple-negative breast cancer patients not treated with radiation therapy when stratified by androgen receptor expression. In multivariable analysis, androgen receptor expression was most significantly associated with worse local recurrence-free survival after radiation therapy (hazard ratio of 3.58) suggesting that androgen receptor expression may be a biomarker of radiation response in triple-negative breast cancer. Inhibition of androgen receptor with MDV3100 (enzalutamide) induced radiation sensitivity (enhancement ratios of 1.22-1.60) in androgen receptor-positive triple-negative breast cancer lines, but did not affect androgen receptor-negative triple-negative breast cancer or estrogen-receptor-positive, androgen receptor-negative breast cancer cell lines. androgen receptor inhibition with MDV3100 significantly radiosensitized triple-negative breast cancer xenografts in mouse models and markedly delayed tumor doubling/tripling time and tumor weight. Radiosensitization was at least partially dependent on impaired dsDNA break repair mediated by DNA protein kinase catalytic subunit. Our results implicate androgen receptor as a mediator of radioresistance in breast cancer and identify androgen receptor inhibition as a potentially effective strategy for the treatment of androgen receptor-positive radioresistant tumors
Evidence for a New Excitation at the Interface Between a High-Tc Superconductor and a Topological Insulator
High-temperature superconductors exhibit a wide variety of novel excitations.
If contacted with a topological insulator, the lifting of spin rotation
symmetry in the surface states can lead to the emergence of unconventional
superconductivity and novel particles. In pursuit of this possibility, we
fabricated high critical-temperature (Tc ~ 85 K) superconductor/topological
insulator (Bi2Sr2CaCu2O8+delta/Bi2Te2Se) junctions. Below 75 K, a zero-bias
conductance peak (ZBCP) emerges in the differential conductance spectra of this
junction. The magnitude of the ZBCP is suppressed at the same rate for magnetic
fields applied parallel or perpendicular to the junction. Furthermore, it can
still be observed and does not split up to at least 8.5 T. The temperature and
magnetic field dependence of the excitation we observe appears to fall outside
the known paradigms for a ZBCP
Holographic dark energy in a universe with spatial curvature and massive neutrinos: a full Markov Chain Monte Carlo exploration
In this paper, we report the results of constraining the holographic dark
energy model with spatial curvature and massive neutrinos, based on a Markov
Chain Monte Carlo global fit technique. The cosmic observational data include
the full WMAP 7-yr temperature and polarization data, the type Ia supernova
data from Union2.1 sample, the baryon acoustic oscillation data from SDSS DR7
and WiggleZ Dark Energy Survey, and the latest measurements of from HST.
To deal with the perturbations of dark energy, we adopt the parameterized
post-Friedmann method. We find that, for the simplest holographic dark energy
model without spatial curvature and massive neutrinos, the phenomenological
parameter at more than confidence level. The inclusion of
spatial curvature enlarges the error bars and leads to only in about
range; in contrast, the inclusion of massive neutrinos does not
have significant influence on . We also find that, for the holographic dark
energy model with spatial curvature but without massive neutrinos, the
error bars of the current fractional curvature density
are still in order of ; for the model with massive neutrinos but
without spatial curvature, the upper bound of the total mass of
neutrinos is eV. Moreover, there exists clear degeneracy
between spatial curvature and massive neutrinos in the holographic dark energy
model, which enlarges the upper bound of by more than 2 times.
In addition, we demonstrate that, making use of the full WMAP data can give
better constraints on the holographic dark energy model, compared with the case
using the WMAP ``distance priors''.Comment: 21 pages, 10 figures; major revision; new figures and discussions
added; accepted by JCA
The lncRNA landscape of breast cancer reveals a role for DSCAM-AS1 in breast cancer progression.
Molecular classification of cancers into subtypes has resulted in an advance in our understanding of tumour biology and treatment response across multiple tumour types. However, to date, cancer profiling has largely focused on protein-coding genes, which comprise <1% of the genome. Here we leverage a compendium of 58,648 long noncoding RNAs (lncRNAs) to subtype 947 breast cancer samples. We show that lncRNA-based profiling categorizes breast tumours by their known molecular subtypes in breast cancer. We identify a cohort of breast cancer-associated and oestrogen-regulated lncRNAs, and investigate the role of the top prioritized oestrogen receptor (ER)-regulated lncRNA, DSCAM-AS1. We demonstrate that DSCAM-AS1 mediates tumour progression and tamoxifen resistance and identify hnRNPL as an interacting protein involved in the mechanism of DSCAM-AS1 action. By highlighting the role of DSCAM-AS1 in breast cancer biology and treatment resistance, this study provides insight into the potential clinical implications of lncRNAs in breast cancer
Prostate cancer incidence across stage, NCCN risk groups, and age before and after USPSTF Grade D recommendations against prostateâ specific antigen screening in 2012
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153721/1/cncr32604.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153721/2/cncr32604_am.pd
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