116 research outputs found
Late Bronze Age Hoard studied by PIXE
The hoards of metallic objects belonging to the Late European Bronze Age can be interpreted
differently depending on the type, number and composition of the artefacts. PIXE analysis has
been performed in nine items from the Hoard of Freixanda in Portugal comprising 4 socket
axes, a palstave axe, a ring, a chisel, a dagger, and a casting debris. Besides the composition
of the main matrix elements, that is Cu and Sn, the amount of trace elements of interest like,
As, Pb, Ni and Ag has been determined using this ion beam technique. The high tin content
alloy and the high purity of the metals from the Freixanda hoard are characteristic of the
Portuguese and Spanish Late Bronze Age metallurgy, supporting the idea of a regional
production
Interstitial Ti for intermediate band formation in Ti-supersaturated silicon
We have analyzed by means of Rutherford backscattering spectrometry (RBS) the Ti lattice location and the degree of crystalline lattice recovery in heavily Ti implanted silicon layers subsequently pulsed laser melted (PLM). Theoretical studies have predicted that Ti should occupy interstitial sites in silicon for a metallic-intermediate band (IB) formation. The analysis of Ti lattice location after PLM processes is a crucial point to evaluate the IB formation that can be clarifyied by means of RBS measurements. After PLM, time-of-flight secondary ion mass spectrometry measurements show that the Ti concentration in the layers is well above the theoretical limit for IB formation. RBS measurements have shown a significant improvement of the lattice quality at the highest PLM energy density studied. The RBS channeling spectra reveals clearly that after PLM processes Ti impurities are mostly occupying interstitial lattice sites
Characterization of surface layers in Zn-diffused LiNbO3 waveguides by heavy ion elastic recoil detection
Copyright (2002) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 81.11 (2002): 1981-1983 and may be found at http://apl.aip.org
Composition, nanostructure, and optical properties of silver and silver-copper lusters
Lusters are composite thin layers of coinage metal nanoparticles in glass displaying peculiar optical
properties and obtained by a process involving ionic exchange, diffusion, and crystallization. In
particular, the origin of the high reflectance (golden-shine) shown by those layers has been subject of
some discussion. It has been attributed to either the presence of larger particles, thinner multiple
layers or higher volume fraction of nanoparticles. The object of this paper is to clarify this for which
a set of laboratory designed lusters are analysed by Rutherford backscattering spectroscopy,
transmission electron microscopy, x-ray diffraction, and ultraviolet-visible spectroscopy. Model
calculations and numerical simulations using the finite difference time domain method were also
performed to evaluate the optical properties. Finally, the correlation between synthesis conditions,
nanostructure, and optical properties is obtained for these materials
Transcriptional Profile Associated with Clinical Outcomes in Metastatic Hormone-Sensitive Prostate Cancer Treated with Androgen Deprivation and Docetaxel
(1) Background: Androgen deprivation therapy (ADT) and docetaxel (DX) combination is a standard therapy for metastatic hormone-sensitive prostate cancer (mHSPC) patients. (2) Methods: We investigate if tumor transcriptomic analysis predicts mHSPC evolution in a multicenter retrospective biomarker study. A customized panel of 184 genes was tested in mRNA from tumor samples by the nCounter platform in 125 mHSPC patients treated with ADT+DX. Gene expression was correlated with castration-resistant prostate cancer-free survival (CRPC-FS) and overall survival (OS). (3) Results: High expression of androgen receptor (AR) signature was independently associated with longer CRPC-FS (hazard ratio (HR) 0.6, 95% confidence interval (CI) 0.3-0.9; p = 0.015), high expression of estrogen receptor (ESR) signature with longer CRPC-FS (HR 0.6, 95% CI 0.4-0.9; p = 0.019) and OS (HR 0.5, 95% CI 0.2-0.9, p = 0.024), and lower expression of tumor suppressor genes (TSG) (RB1, PTEN and TP53) with shorter OS (HR 2, 95% CI 1-3.8; p = 0.044). ARV7 expression was independently associated with shorter CRPC-FS (HR 1.5, 95% CI 1.1-2.1, p = 0.008) and OS (HR 1.8, 95% CI 1.2-2.6, p = 0.004), high ESR2 was associated with longer OS (HR 0.5, 95% CI 0.2-1, p = 0.048) and low expression of RB1 was independently associated with shorter OS (HR 1.9, 95% CI 1.1-3.2, p = 0.014). (4) Conclusions: AR, ESR, and TSG expression signatures, as well as ARV7, RB1, and ESR2 expression, have a prognostic value in mHSPC patients treated with ADT+DX
Bonding and hardness in nonhydrogenated carbon films with moderate sp3 content
Amorphous carbon films with an s p{sup 3} content up to 25% and a negligible amount of hydrogen have been grown by evaporation of graphite and concurrent Ar{sup +} ion bombardment. The s p{sup 3} content is maximized for Ar{sup +} energies between 200 and 300 eV following a subplantation mechanism. Higher ion energies deteriorate the film due to sputtering and heating processes. The hardness of the films increases in the optimal assisting range from 8 to 18 GPa, and is explained by the crosslinking of graphitic planes through s p {sup 3} connecting site
Local primordial non-Gaussianity from the large-scale clustering of photometric DESI luminous red galaxies
We use angular clustering of luminous red galaxies from the Dark Energy
Spectroscopic Instrument (DESI) imaging surveys to constrain the local
primordial non-Gaussianity parameter fNL. Our sample comprises over 12 million
targets, covering 14,000 square degrees of the sky, with redshifts in the range
0.2< z < 1.35. We identify Galactic extinction, survey depth, and astronomical
seeing as the primary sources of systematic error, and employ linear regression
and artificial neural networks to alleviate non-cosmological excess clustering
on large scales. Our methods are tested against log-normal simulations with and
without fNL and systematics, showing superior performance of the neural network
treatment in reducing remaining systematics. Assuming the universality
relation, we find fNL at 68\%(95\%) confidence.
With a more aggressive treatment, including regression against the full set of
imaging maps, our maximum likelihood value shifts slightly to fNL and
the uncertainty on fNL increases due to the removal of large-scale clustering
information. We apply a series of robustness tests (e.g., cuts on imaging,
declination, or scales used) that show consistency in the obtained constraints.
Despite extensive efforts to mitigate systematics, our measurements indicate
fNL > 0 with a 99.9 percent confidence level. This outcome raises concerns as
it could be attributed to unforeseen systematics, including calibration errors
or uncertainties associated with low-\ell systematics in the extinction
template. Alternatively, it could suggest a scale-dependent fNL model--causing
significant non-Gaussianity around large-scale structure while leaving cosmic
microwave background scales unaffected. Our results encourage further studies
of fNL with DESI spectroscopic samples, where the inclusion of 3D clustering
modes should help separate imaging systematics.Comment: 19 pages, 15 figures, 6 tables (Appendix excluded). Submitted to
MNRA
Androgen receptor gene status in plasma DNA associates with worse outcome on enzalutamide or abiraterone for castration-resistant prostate cancer: a multi-institution correlative biomarker study
2632A>G (p.T878A)] were observed in eight (11%) post-docetaxel but no chemotherapy-naı¨ve abiraterone-treated patients and were also associated with worse OS (HR 3.26; 95% CI 1.47-not reached; P¼0.004). There was no interaction between AR and docetaxel status (P¼0.83 for OS, P¼0.99 for PFS). In the PREMIERE trial, 11 patients (12%) with AR gain had worse PSA-PFS (sPFS) (HR 4.33; 95% CI 1.94-9.68; PA (p.L702H) and 520 3
Androgen receptor gene status in plasma DNA associates with worse outcome on enzalutamide or abiraterone for castration-resistant prostate cancer: a multi-institution correlative biomarker study.
Background There is an urgent need to identify biomarkers to guide personalized therapy in castration-resistant prostate cancer (CRPC). We aimed to clinically qualify androgen receptor (AR) gene status measurement in plasma DNA using multiplex droplet digital PCR (ddPCR) in pre- and post-chemotherapy CRPC.Methods We optimized ddPCR assays for AR copy number and mutations and retrospectively analyzed plasma DNA from patients recruited to one of the three biomarker protocols with prospectively collected clinical data. We evaluated associations between plasma AR and overall survival (OS) and progression-free survival (PFS) in 73 chemotherapy-naïve and 98 post-docetaxel CRPC patients treated with enzalutamide or abiraterone (Primary cohort) and 94 chemotherapy-naïve patients treated with enzalutamide (Secondary cohort; PREMIERE trial).Results In the primary cohort, AR gain was observed in 10 (14%) chemotherapy-naïve and 33 (34%) post-docetaxel patients and associated with worse OS [hazard ratio (HR), 3.98; 95% CI 1.74-9.10; P A (p.L702H) and 2632A>G (p.T878A)] were observed in eight (11%) post-docetaxel but no chemotherapy-naïve abiraterone-treated patients and were also associated with worse OS (HR 3.26; 95% CI 1.47-not reached; P = 0.004). There was no interaction between AR and docetaxel status (P = 0.83 for OS, P = 0.99 for PFS). In the PREMIERE trial, 11 patients (12%) with AR gain had worse PSA-PFS (sPFS) (HR 4.33; 95% CI 1.94-9.68; P < 0.001), radiographic-PFS (rPFS) (HR 8.06; 95% CI 3.26-19.93; P < 0.001) and OS (HR 11.08; 95% CI 2.16-56.95; P = 0.004). Plasma AR was an independent predictor of outcome on multivariable analyses in both cohorts.Conclusion Plasma AR status assessment using ddPCR identifies CRPC with worse outcome to enzalutamide or abiraterone. Prospective evaluation of treatment decisions based on plasma AR is now required.Clinical trial number NCT02288936 (PREMIERE trial)
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