319 research outputs found
Optical-Absorption in Undoped Yttrium-Aluminum-Garnet
Roomâtemperature optical absorption over a large dynamic range is reported for singleâ crystal undoped yttrium aluminum garnet (Y3Al5O12 or YAG). Absorption results are presented for the energy ranges 1.8 to 3.0 and 4.5 to 6.5 eV. For this work, ultraviolet (UV) absorption measurements were performed on four different boules of Czochralskiâgrown undoped YAG. Absorption features were observed at 4.8 and 5.6 eV which can be attributed, at least in part, to trace impurity concentrations. Along with the UV measurements, calorimetric absorption results are presented at several laser wavelengths in the visible and near infrared (IR). The calorimetric results suggest a value of 1.5Ă10â3 cmâ1 for the absorption coefficient of undoped YAG in the red and near IR. From the combination of UV and calorimetric measurements, an empirical estimate of the absorption coefficient from the visible to the UV is presented for undoped YAG. In addition to the absorption spectra, detailed chemical analyses and sample histories are given for the asâgrown optical quality YAG utilized herein
The Dietary Intake of Polyphenols Is Associated with a Lower Risk of Severe Lumbar Spinal Stenosis: A Case-Control Analysis from the PREFACE Study
Polyphenols are naturally occurring compounds endowed with antioxidant and anti-inflammatory properties. We sought to examine the association of dietary polyphenols with the risk of severe lumbar spinal stenosis (LSS), a condition possibly characterized by a high inflammatory component. A case-control study included 156 patients with LSS and indication to surgery and 312 controls, matched (1:2) for sex, age (±6 months), and physical activity. The polyphenol intake was calculated by matching food consumption data from a 188-item food frequency questionnaire with the Phenol-Explorer database regarding the polyphenol content of each reported food. In a multivariable-adjusted logistic regression analysis including lifestyles, sociodemographic factors, and the Mediterranean Diet Score, a 1-standard deviation (SD) increase in dietary polyphenols intake was associated with lower odds of LSS (Odds ratio [OR] = 0.65; 95% CI: 0.47â0.89). Analyses of different polyphenol classes showed that a per 1-SD in the consumption of flavonoids and stilbenes was related to lower LSS risk (OR = 0.57; 95% CI: 0.42â0.78; OR = 0.40; 95% CI: 0.27â0.61, respectively). Further adjustment for the total dietary antioxidant capacity did not modify the strength of these associations. A diet rich in polyphenols is independently associated with a lower risk of severe LSS, possibly through mechanisms that include the anti-inflammatory potential of these bioactive compounds
Room-Temperature Optical-Absorption in Undoped Alpha-AL2O3
Optical absorption over a large dynamic range obtained by two different experimental techniques is reported for an undoped αâAl2 O3 single crystal. Absorption data are presented in two energy ranges: 0.94â3.5 eV and 4.5â8.6 eV. Vacuum ultraviolet (vuv) absorption measurements were performed on three boules of Czochralskiâgrown singleâcrystal Al2 O3 with differing starting material purities. The initial powder purities were 99.99%, 99.999%, and 99.999999%. In addition to the vuv measurements, calorimetric absorption results obtained in the visible and nearâinfrared (ir) are presented. An empirical formula is obtained that provides an estimate of the absorption coefficient from the nearâir to the vuv for undoped Al2 O3 . Detailed impurity analyses and sample histories are given for the opticalâquality αâAl2 O3 utilized herein
What Is Italian Antispeciesism? An Overview of Recent Tendencies in Animal Advocacy
This chapter offers an overview of the different agents currently operating in Italy as part of the animal liberation movement. It analyses the impact on this social reality by books and essays published or translated in Italian in the last 20 years in the field of Animal Ethics. From the reception of Peter Singer and Tom Regan\u2019s ideas mediated by the work of Paola Cavalieri, Italian philosophers have shaped the narratives and the rhetoric of animal advocates and liberationists. On the other side, activists\u2019 debates on the best strategies to adopt involved intellectuals and enriched their production on Animal Liberation. Groups with an intersectional approach have paid particular attention to theoretical implications and political consequences of their acts, developing radical, non-anthropocentric forms of antispeciesism
Preparation of TiO2 Anatase Nanocrystals by TiCl4 Hydrolysis with Additive H2SO4
A new methodology was developed to synthesize uniform titania anatase nanocrystals by the hydrolysis of titanium chloride in sulfuric acid aqueous solutions at 0â90°C. The samples were characterized by Raman spectroscopy, UV-visible spectroscopy, transmission electron microscopy (TEM), electron diffraction (ED), and an Energy dispersive X-ray spectroscopy (EDS). The effects of the reaction temperature, mole ratio of SO42â to Ti4+, and the calcinations temperature on the particle size and crystal phase were investigated. Depending on the acidity, the hydrolysis temperature, and the calcination temperature, rhombic anatase nanocrystals sizes in the range of 10 nm to 50 nm were obtained. In the additive of sulfuric acid, Raman spectra and electron diffraction confirmed that the nanoparticles are composed of anatase TiO2. No other titania phases, such as rutile or brookite, were detected
Metatypical basal cell carcinoma: a clinical review
Background. Metatypical cell carcinoma can be considered as a new entity of skin cancer, being an intermediate typology between basal cell carcinomas and squamous cell carcinomas. The behaviour of the metatypical cell carcinoma lies between these two varieties of skin cancer. It is difficult to perform a differential diagnosis based on morphological and clinical features - therefore it is only possible by accurate histology. Methods. The authors have retrospectively analysed clinical records of 240 patients who were affected by metatypical skin cancer and who were treated by surgery, radiotherapy and chemotherapy. Results. MTC affected more males than females (62.5% vs 37.5%) than males. The most affected site was the cervicofacial area, 71.7%; then the trunk, 10%; the limbs, 9.6%; the scalp 3.7%; and other regions 5%. A recurrence occurred in 24 cases (10%), mainly in head and neck area. Conclusion. In this manuscript, the authors have emphasised the importance of conducting a differential diagnosis, and the importance of the specific treatment for metatypical skin cancer, even though more clinical studies and long-term follow-ups are required before establishing specific guidelines. © 2008 Tarallo et al; licensee BioMed Central Ltd
Thermal and Optical Characterization of Undoped and Neodymium-Doped Y3ScAl4O12 Ceramics
Y3â3xNd3xSc1Al4O12 (x = 0, 0.01, and 0.02) ceramics were fabricated by sintering at high temperature under vacuum. Unit cell parameter refinement and chemical analysis have been performed. The morphological characterization shows micrograins with no visible defects. The thermal analysis of these ceramics is presented, by measuring the specific heat in the temperature range from 300 to 500 K. Their values at room temperature are in the range 0.81â0.90 J g1âKâ1. The thermal conductivity has been determined by two methods: by the experimental measurement of the thermal diffusivity by the photopyroelectric method, and by spectroscopy, evaluating the thermal load. The thermal conductivities are in the range 9.7â6.5 W Kâ1 mâ1 in the temperature interval from 300 to 500 K. The thermooptic coefficients were measured at 632 nm by the dark mode method using a prism coupler, and the obtained values are in the range 12.8â13.3 Ă 10â6 Kâ1. The nonlinear refractive index values at 795 nm have been evaluated to calibrate the nonlinear optical response of these materials.This work is supported by the Spanish Government under projects MAT2011-29255-C02-01-02, MAT2013-47395-C4-4-R, and the Catalan Government under project 2014SGR1358. It was also funded by the European Commission under the Seventh Framework Programme, project Cleanspace, FP7-SPACE-2010-1-GA No. 263044
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