Two-Dimensional Nuclear Magnetic Resonance Structure Determination Module for Introductory Biochemistry: Synthesis and Structural Characterization of Lyso-Glycerophospholipids

ERIC Educational Resources Information Center

Garrett, Teresa A.; Rose, Rebecca L.; Bell, Sidney M.

2013-01-01

In this laboratory module, introductory biochemistry students are exposed to two-dimensional [superscript 1]H-nuclear magnetic resonance of glycerophospholipids (GPLs). Working in groups of three, students enzymatically synthesized and purified a variety of 2-acyl lyso GPLs. The structure of the 2-acyl lyso GPL was verified using [superscript…

Production of Zr-89 using sputtered yttrium coin targets 89Zr using sputtered yttrium coin targets.

PubMed

Queern, Stacy Lee; Aweda, Tolulope Aramide; Massicano, Adriana Vidal Fernandes; Clanton, Nicholas Ashby; El Sayed, Retta; Sader, Jayden Andrew; Zyuzin, Alexander; Lapi, Suzanne Elizabeth

2017-07-01

An increasing interest in zirconium-89 ( 89 Zr) can be attributed to the isotope's half-life which is compatible with antibody imaging using positron emission tomography (PET). The goal of this work was to develop an efficient means of production for 89 Zr that provides this isotope with high radionuclidic purity and specific activity. We investigated the irradiation of yttrium sputtered niobium coins and compared the yields and separation efficiency to solid yttrium coins. The sputtered coins were irradiated with an incident beam energy of 17.5MeV or 17.8MeV providing a degraded transmitted energy through an aluminum degrader of 12.5MeV or 12.8MeV, respectively, with various currents to determine optimal cyclotron conditions for 89 Zr production. Dissolution of the solid yttrium coin took 2h with 50mL of 2M HCl and dissolution of the sputtered coin took 15-30min with 4mL of 2M HCl. During the separation of 89 Zr from the solid yttrium coins, 77.9 ± 11.2% of the activity was eluted off in an average of 7.3mL of 1M oxalic acid whereas for the sputtered coins, 91 ± 6% was eluted off in an average of 1.2mL of 1M oxalic acid with 100% radionuclidic purity. The effective specific activity determined via DFO-SCN titration from the sputtered coins was 108±7mCi/μmol as compared to 20.3mCi/μmol for the solid yttrium coin production. ICP-MS analysis of the yttrium coin and the sputtered coins showed 99.99% yttrium removed with 178μg of yttrium in the final solution and 99.93-100% of yttrium removed with remaining range of 0-42μg of yttrium in the final solution, respectively. The specific activity calculated for the solid coin and 3 different sputtered coins using the concentration of Zr found via ICP-MS was 140±2mCi/μmol, 300±30mCi/μmol, 410±60mCi/μmol and 1719±5mCi/μmol, respectively. Labeling yields of the 89 Zr produced via sputtered targets for 89 Zr- DFO-trastuzumab were >98%. Overall, these results show the irradiation of yttrium sputtered niobium coins

Absolute measurements of fast neutrons using yttrium.

PubMed

Roshan, M V; Springham, S V; Rawat, R S; Lee, P; Krishnan, M

2010-08-01

Yttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be f(n) approximately 4.1x10(-4) with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 10(8) neutrons per discharge.

LysoTracker and MitoTracker Red are transport substrates of P-glycoprotein: implications for anticancer drug design evading multidrug resistance.

PubMed

Zhitomirsky, Benny; Farber, Hodaya; Assaraf, Yehuda G

2018-04-01

LysoTracker and MitoTracker Red are fluorescent probes widely used for viable cell staining of lysosomes and mitochondria, respectively. They are utilized to study organelle localization and their resident proteins, assess organelle functionality and quantification of organelle numbers. The ATP-driven efflux transporter P-glycoprotein (P-gp) is expressed in normal and malignant tissues and extrudes structurally distinct endogenous and exogenous cytotoxic compounds. Thus, once aromatic hydrophobic compounds such as the above-mentioned fluorescent probes are recognized as transport substrates, efflux pumps including P-gp may abolish their ability to reach their cellular target organelles. Herein, we show that LysoTracker and MitoTracker Red are expelled from P-gp-overexpressing cancer cells, thus hindering their ability to fluorescently mark target organelles. We further demonstrate that tariquidar, a potent P-gp transport inhibitor, restores LysoTracker and MitoTracker Red cell entry. We conclude that LysoTracker and MitoTracker Red are P-gp transport substrates, and therefore, P-gp expression must be taken into consideration prior to cellular applications using these probes. Importantly, as MitoTracker was a superior P-gp substrate than LysoTracker Red, we discuss the implications for the future design of chemotherapeutics evading cancer multidrug resistance. Furthermore, restoration of MitoTracker Red fluorescence in P-gp-overexpressing cells may facilitate the identification of potent P-gp transport inhibitors (i.e. chemosensitizers). © 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Lyso-DGTS lipid isolated from microalgae enhances PON1 activities in vitro and in vivo, increases PON1 penetration into macrophages and decreases cellular lipid accumulation.

PubMed

Dahli, Loureen; Atrahimovich, Dana; Vaya, Jacob; Khatib, Soliman

2018-04-16

High-density lipoprotein (HDL) plays an important role in preventing atherosclerosis. The antioxidant effect of HDL is mostly associated with paraoxonase 1 (PON1) activity. Increasing PON1 activity using nutrients might improve HDL function and quality and thus, decrease atherosclerotic risk. We previously isolated and identified a novel active compound, lyso-DGTS (C20:5,0) from Nannochloropsis sp. ethanol extract. In the present study, its effect on PON1 activities was examined and the mechanism by which the compound affects PON1 activity was explored. Lyso-DGTS elevated recombinant PON1 (rePON1) lactonase and esterase activities in a dose- and time-responsive manner, and further stabilized and preserved rePON1 lactonase activity. Incubation of lyso-DGTS with human serum for 4 h at 37°C also increased PON1 lactonase activity in a dose-responsive manner. Using tryptophan-fluorescence-quenching assay, lyso-DGTS was found to interact with rePON1 spontaneously with negative free energy (ΔG = -22.87 kJ mol -1 at 25°C). Thermodynamic parameters and molecular modeling calculations showed that the main interaction of lyso-DGTS with the enzyme is through a hydrogen bond with supporting van der Waals interactions. Furthermore, lyso-DGTS significantly increased rePON1 influx into macrophages and prevented lipid accumulation in macrophages stimulated with oxidized low-density lipid dose-dependently. In vivo supplementation of lyso-DGTS to the circulation of mice fed a high-fat diet via osmotic mini-pumps implanted subcutaneously significantly increased serum PON1 lactonase activity and decreased serum glucose concentrations to the level of mice fed a normal diet. Our findings suggest a beneficial effect of lyso-DGTS on increasing PON1 activity and thus, improving HDL quality and atherosclerotic risk factors. © 2018 BioFactors, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

Lithium Iron Orthosilicate Cathode: Progress and Perspectives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ni, Jiangfeng; Jiang, Yu; Bi, Xuanxuan

2017-07-18

The pursuit of cathodes with a high capacity is remarkably driven by the ever increasing demand of high-energy lithium ion batteries in electronics and transportation. In this regard, polyanionic lithium iron orthosilicate (Li2FeSiO4) offers a promising opportunity because it affords a high theoretical capacity of 331 mAh g–1. However, such a high theoretical capacity of Li2FeSiO4 has frequently been compromised in practice because of the extremely low electronic and ionic conductivity. To address this issue, material engineering strategies to boost the Li storage kinetics in Li2FeSiO4 have proven indispensable. In this Perspective, we will briefly present the structural characteristics, intrinsicmore » physicochemical properties, and electrochemical behavior of Li2FeSiO4. We particularly focus on recent materials engineering of silicates, which is implemented mainly through advanced synthetic techniques and elaborate controls. This Perspective highlights the importance of integrating theoretical analysis into experimental implementation to further advance the Li2FeSiO4 materials.« less

Comparison of acrylic polymer adhesive tapes and silicone optical grease in light sharing detectors for positron emission tomography.

PubMed

Van Elburg, Devin J; Noble, Scott D; Hagey, Simone; Goertzen, Andrew L

2018-02-26

Optical coupling is an important factor in detector design as it improves optical photon transmission by mitigating internal reflections at light-sharing boundaries. In this work we compare optical coupling materials, namely double-sided acrylic polymer tapes and silicone optical grease (SiG), in the context of positron emission tomography. Four double-sided tapes from 3 M of varying thicknesses (0.229 mm-1.016 mm) and adhesive materials ('100MP', 'A100', and 'GPA') were characterized with spectrophotometer measurements as well as photopeak amplitude and energy resolution measurements using lutetium-yttrium oxy-orthosilicate (LYSO) coupled to photomultiplier tubes (PMT) or silicon photomultipliers (SiPMs). Transmission spectra from the spectrophotometer showed over 80% transmission for all tapes at 420 nm and above, with 89.6% and 88.8% transmission for the 0.508 mm and 1.016 mm thick GPA tapes, respectively, at 420 nm. Measurements with single-pixel LYSO-PMT and 4  ×  4 array (one-to-one coupled) LYSO-SiPM setups determined that SiG had the greatest photopeak amplitude, with tapes showing 2.1%-14.8% reduction in photopeak amplitude with respect to SiG. Energy resolution changed by less than 4% on a relative basis between tapes and SiG with PMT measurements, however for the SiPM array measurements the energy resolution improved from 15.6%  ±  2.7% full-width at half-maximum to 11.4%  ±  1.2% for SiG and 1 mm GPA respectively. Data acquired with dual-layer offset LYSO arrays (light sharing detector designs) demonstrated that a detector coupled with 1 mm thick GPA tape produced equivalent detector flood histograms to those from a design coupled with SiG and a 1 mm thick glass lightguide. No significant degradation in photopeak amplitude and energy resolution was observed over five months of measurements, indicating the tapes maintain their coupling integrity over several months. Though minimal photopeak amplitude degradation

Comparison of acrylic polymer adhesive tapes and silicone optical grease in light sharing detectors for positron emission tomography

NASA Astrophysics Data System (ADS)

Van Elburg, Devin J.; Noble, Scott D.; Hagey, Simone; Goertzen, Andrew L.

2018-03-01

Optical coupling is an important factor in detector design as it improves optical photon transmission by mitigating internal reflections at light-sharing boundaries. In this work we compare optical coupling materials, namely double-sided acrylic polymer tapes and silicone optical grease (SiG), in the context of positron emission tomography. Four double-sided tapes from 3 M of varying thicknesses (0.229 mm-1.016 mm) and adhesive materials (‘100MP’, ‘A100’, and ‘GPA’) were characterized with spectrophotometer measurements as well as photopeak amplitude and energy resolution measurements using lutetium-yttrium oxy-orthosilicate (LYSO) coupled to photomultiplier tubes (PMT) or silicon photomultipliers (SiPMs). Transmission spectra from the spectrophotometer showed over 80% transmission for all tapes at 420 nm and above, with 89.6% and 88.8% transmission for the 0.508 mm and 1.016 mm thick GPA tapes, respectively, at 420 nm. Measurements with single-pixel LYSO-PMT and 4  ×  4 array (one-to-one coupled) LYSO-SiPM setups determined that SiG had the greatest photopeak amplitude, with tapes showing 2.1%-14.8% reduction in photopeak amplitude with respect to SiG. Energy resolution changed by less than 4% on a relative basis between tapes and SiG with PMT measurements, however for the SiPM array measurements the energy resolution improved from 15.6%  ±  2.7% full-width at half-maximum to 11.4%  ±  1.2% for SiG and 1 mm GPA respectively. Data acquired with dual-layer offset LYSO arrays (light sharing detector designs) demonstrated that a detector coupled with 1 mm thick GPA tape produced equivalent detector flood histograms to those from a design coupled with SiG and a 1 mm thick glass lightguide. No significant degradation in photopeak amplitude and energy resolution was observed over five months of measurements, indicating the tapes maintain their coupling integrity over several months. Though minimal photopeak amplitude

LYSO based precision timing calorimeters

DOE PAGES

Bornheim, A.; Apresyan, A.; Ronzhin, A.; ...

2017-11-01

In this report we outline the study of the development of calorimeter detectors using bright scintillating crystals. We discuss how timing information with a precision of a few tens of pico seconds and below can significantly improve the reconstruction of the physics events under challenging high pileup conditions to be faced at the High-Luminosity LHC or a future hadron collider. The particular challenge in measuring the time of arrival of a high energy photon lies in the stochastic component of the distance of initial conversion and the size of the electromagnetic shower. We present studies and measurements from test beamsmore » for calorimeter based timing measurements to explore the ultimate timing precision achievable for high energy photons of 10 GeV and above. We focus on techniques to measure the timing with a high precision in association with the energy of the photon. We present test-beam studies and results on the timing performance and characterization of the time resolution of LYSO-based calorimeters. We demonstrate time resolution of 30 ps is achievable for a particular design.« less

LYSO based precision timing calorimeters

NASA Astrophysics Data System (ADS)

Bornheim, A.; Apresyan, A.; Ronzhin, A.; Xie, S.; Duarte, J.; Spiropulu, M.; Trevor, J.; Anderson, D.; Pena, C.; Hassanshahi, M. H.

2017-11-01

In this report we outline the study of the development of calorimeter detectors using bright scintillating crystals. We discuss how timing information with a precision of a few tens of pico seconds and below can significantly improve the reconstruction of the physics events under challenging high pileup conditions to be faced at the High-Luminosity LHC or a future hadron collider. The particular challenge in measuring the time of arrival of a high energy photon lies in the stochastic component of the distance of initial conversion and the size of the electromagnetic shower. We present studies and measurements from test beams for calorimeter based timing measurements to explore the ultimate timing precision achievable for high energy photons of 10 GeV and above. We focus on techniques to measure the timing with a high precision in association with the energy of the photon. We present test-beam studies and results on the timing performance and characterization of the time resolution of LYSO-based calorimeters. We demonstrate time resolution of 30 ps is achievable for a particular design.

Effectiveness of plasma lyso-Gb3 as a biomarker for selecting high-risk patients with Fabry disease from multispecialty clinics for genetic analysis.

PubMed

Maruyama, Hiroki; Miyata, Kaori; Mikame, Mariko; Taguchi, Atsumi; Guili, Chu; Shimura, Masaru; Murayama, Kei; Inoue, Takeshi; Yamamoto, Saori; Sugimura, Koichiro; Tamita, Koichi; Kawasaki, Toshihiro; Kajihara, Jun; Onishi, Akifumi; Sugiyama, Hitoshi; Sakai, Teiko; Murata, Ichijiro; Oda, Takamasa; Toyoda, Shigeru; Hanawa, Kenichiro; Fujimura, Takeo; Ura, Shigehisa; Matsumura, Mimiko; Takano, Hideki; Yamashita, Satoshi; Matsukura, Gaku; Tazawa, Ryushi; Shiga, Tsuyoshi; Ebato, Mio; Satoh, Hiroshi; Ishii, Satoshi

2018-03-15

PurposePlasma globotriaosylsphingosine (lyso-Gb3) is a promising secondary screening biomarker for Fabry disease. Here, we examined its applicability as a primary screening biomarker for classic and late-onset Fabry disease in males and females.MethodsBetween 1 July 2014 and 31 December 2015, we screened 2,360 patients (1,324 males) referred from 169 Japanese specialty clinics (cardiology, nephrology, neurology, and pediatrics), based on clinical symptoms suggestive of Fabry disease. We used the plasma lyso-Gb3 concentration, α-galactosidase A (α-Gal A) activity, and analysis of the α-Gal A gene (GLA) for primary and secondary screens, respectively.ResultsOf 8 males with elevated lyso-Gb3 levels (≥2.0 ng ml -1 ) and low α-Gal A activity (≤4.0 nmol h -1  ml -1 ), 7 presented a GLA mutation (2 classic and 5 late-onset). Of 15 females with elevated lyso-Gb3, 7 displayed low α-Gal A activity (5 with GLA mutations; 4 classic and 1 late-onset) and 8 exhibited normal α-Gal A activity (1 with a classic GLA mutation and 3 with genetic variants of uncertain significance).ConclusionPlasma lyso-Gb3 is a potential primary screening biomarker for classic and late-onset Fabry disease probands.Genet Med advance online publication, 15 March 2018; doi:10.1038/gim.2018.31.

Role of protein kinase A and class II phosphatidylinositol 3-kinase C2β in the downregulation of KCa3.1 channel synthesis and membrane surface expression by lyso-globotriaosylceramide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Ju Yeon; Park, Seonghee, E-mail: sp@ewha.ac.kr

The intermediate conductance calcium-activated potassium channel (KCa3.1) mediates proliferation of many cell types including fibroblasts, and is a molecular target for intervention in various cell proliferative diseases. Our previous study showed that reduction of KCa3.1 channel expression by lyso-globotriaosylceramide (lyso-Gb3) inhibits differentiation into myofibroblasts and collagen synthesis, which might lead to development of ascending thoracic aortic aneurysm secondary to Fabry disease. However, how lyso-Gb3 downregulates KCa3.1 channel expression is unknown. Therefore, we aimed to investigate the underlying mechanisms of lyso-Gb3-mediated KCa3.1 channel downregulation, focusing on the cAMP signaling pathway. We found that lyso-Gb3 increased the intracellular cAMP concentration by upregulationmore » of adenylyl cyclase 6 and inhibited ERK 1/2 phosphorylation through the protein kinase A (PKA) pathway, leading to the inhibition of KCa3.1 channel synthesis, not the exchange protein directly activated by cAMP (Epac) pathway. Moreover, lyso-Gb3 suppressed expression of class II phosphatidylinositol 3-kinase C2β (PI3KC2β) by PKA activation, which reduces the production of phosphatidylinositol 3-phosphate [PI(3)P], and the reduced membrane surface expression of KCa3.1 channel was recovered by increasing the intracellular levels of PI(3)P. Consequently, our findings that lyso-Gb3 inhibited both KCa3.1 channel synthesis and surface expression by increasing intracellular cAMP, and controlled surface expression through changes in PI3KC2β-mediated PI(3)P production, suggest that modulation of PKA and PI3KC2β activity to control of KCa3.1 channel expression can be an alternative important target to attenuate ascending thoracic aortic aneurysms in Fabry disease. - Highlights: • Lyso-Gb3 causes elevation of intracellular cAMP. • Lyso-Gb3 inhibits the ERK 1/2 phosphorylation through PKA, thereby reducing KCa3.1 channel synthesis. • Lyso-Gb3 reduces PI3KC2�

Biokinetics of yttrium and comparison with its geochemical twin holmium

DOE PAGES

Leggett, Rich

2017-06-01

The transition metal yttrium (Y, atomic number 39) is chemically similar to elements in the lanthanide family (atomic numbers 57-71, lanthanum through lutetium) and is always present with the lanthanides in rare earth ores. Yttrium and the lanthanide holmium are particularly close chemical and physical analogues and are referred to as geochemical twins because they typically show little fractionation in geological material. Extensive measurements on rocks, soils, and meteorites indicate that the Y/Ho mass concentration ratio rarely falls far from the “chondritic” or “solar system” ratio of ~26. Our paper presents a new biokinetic model for yttrium in adult humansmore » and examines whether yttrium and holmium may be biological as well as geochemical twins. Collected data on yttrium and holmium in plants and human tissues do not allow precise derivations of Y/Ho concentration ratios but with occasional exceptions yield ratios that are reasonably consistent with chondritic values. Predictions of the time-dependent behavior of yttrium in adult humans based on the yttrium model presented here closely approximate predictions of the behavior of holmium based on a previously developed model for holmium. We know that yttrium and holmium are close biological analogues, but the available comparative data are too limited and imprecise to reveal whether there are any significant differences in their biological behavior.« less

Apical sorting of lysoGPI-anchored proteins occurs independent of association with detergent-resistant membranes but dependent on their N-glycosylation.

PubMed

Castillon, Guillaume Alain; Michon, Laetitia; Watanabe, Reika

2013-06-01

Most glycosylphosphatidylinositol-anchored proteins (GPI-APs) are located at the apical surface of epithelial cells. The apical delivery of GPI-APs is believed to result from their association with lipid rafts. We find that overexpression of C-terminally tagged PGAP3 caused predominant production of lysoGPI-APs, an intermediate precursor in the GPI lipid remodeling process in Madin-Darby canine kidney cells. In these cells, produced lysoGPI-APs are not incorporated into detergent-resistant membranes (DRMs) but still are delivered apically, suggesting that GPI-AP association with DRMs is not necessary for apical targeting. In contrast, apical transport of both fully remodeled and lyso forms of GPI-APs is dependent on N-glycosylation, confirming a general role of N-glycans in apical protein transport. We also find that depletion of cholesterol causes apical-to-basolateral retargeting not only of fully remodeled GPI-APs, but also of lysoGPI-APs, as well as endogenous soluble and transmembrane proteins that would normally be targeted to the apical membrane. These findings confirm the essential role for cholesterol in the apical protein targeting and further demonstrate that the mechanism of cholesterol-dependent apical sorting is not related to DRM association of GPI-APs.

Rare earths, the lanthanides, yttrium and scandium

USGS Publications Warehouse

Hedrick, J.B.

2006-01-01

In 2005, rare earths were not mined in the United States. The major supplier, Molycorp, continued to maintain a large stockpile of rare-earth concentrates and compounds. Consumption decreased of refined rare-earth products. The United States remained a major importer and exporter of rare earths in 2005. During the same period, yttrium was not mined or refined in the US. Hence, supply of yttrium compounds for refined yttrium products came from China, France and Japan. Scandium was not also mined. World production was primarily in China, Russia and Ukraine. Demand for rare earths in 2006 is expected to be closely tied to economic conditions in the US.

LYSO-based precision timing detectors with SiPM readout

NASA Astrophysics Data System (ADS)

Bornheim, A.; Hassanshahi, M. H.; Griffioen, M.; Mao, J.; Mangu, A.; Peña, C.; Spiropulu, M.; Xie, S.; Zhang, Z.

2018-07-01

Particle detectors based on scintillation light are particularly well suited for precision timing applications with resolutions of a few 10's of ps. The large primary signal and the initial rise time of the scintillation light result in very favorable signal-to-noise conditions with fast signals. In this paper we describe timing studies using a LYSO-based sampling calorimeter with wavelength-shifting capillary light extraction and silicon photomultipliers as photosensors. We study the contributions of various steps of the signal generation to the total time resolution, and demonstrate its feasibility as a radiation-hard technology for calorimeters at high intensity hadron colliders.

Structural phase transitions in yttrium under ultrahigh pressures

NASA Astrophysics Data System (ADS)

Samudrala, Gopi K.; Tsoi, Georgiy M.; Vohra, Yogesh K.

2012-09-01

X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.

Structural phase transitions in yttrium under ultrahigh pressures.

PubMed

Samudrala, Gopi K; Tsoi, Georgiy M; Vohra, Yogesh K

2012-09-12

X-ray diffraction studies were carried out on the rare earth metal yttrium up to 177 GPa in a diamond anvil cell at room temperature. Yttrium was compressed to 37% of its initial volume at the highest pressure. The rare earth crystal structure sequence hcp → Sm type → dhcp → mixed(dhcp + fcc) → distorted fcc (dfcc) is observed in yttrium below 50 GPa. The dfcc (hR24) phase has been observed to persist in the pressure range of 50-95 GPa. A structural transition from dfcc to a low symmetry phase has been observed in yttrium at 99 ± 4 GPa with a volume change of - 2.6%. This low symmetry phase has been identified as a monoclinic C2/m phase, which has also been observed in other rare earth elements under high pressures. The appearance of this low symmetry monoclinic phase in yttrium shows that its electronic structure under extreme conditions resembles that of heavy rare earth metals, with a significant increase in d-band character of the valence electrons and possibly some f-electron states near the Fermi level.

Validation of a highly integrated SiPM readout system with a TOF-PET demonstrator

NASA Astrophysics Data System (ADS)

Niknejad, T.; Setayeshi, S.; Tavernier, S.; Bugalho, R.; Ferramacho, L.; Di Francesco, A.; Leong, C.; Rolo, M. D.; Shamshirsaz, M.; Silva, J. C.; Silva, R.; Silveira, M.; Zorraquino, C.; Varela, J.

2016-12-01

We have developed a highly integrated, fast and compact readout electronics for Silicon Photomultiplier (SiPM) based Time of Flight Positron Emission Tomography (TOF-PET) scanners. The readout is based on the use of TOP-PET Application Specific Integrated Circuit (PETsys TOFPET1 ASIC) with 64 channels, each with its amplifier, discriminator, Time to Digital Converter (TDC) and amplitude determination using Time Over Threshold (TOT). The ASIC has 25 ps r.m.s. intrinsic time resolution and fully digital output. The system is optimised for high rates, good timing, low power consumption and low cost. For validating the readout electronics, we have built a technical PET scanner, hereafter called ``demonstrator'', with 2'048 SiPM channels. The PET demonstrator has 16 compact Detector Modules (DM). Each DM has two ASICs reading 128 SiPM pixels in one-to-one coupling to 128 Lutetium Yttrium Orthosilicate (LYSO) crystals measuring 3.1 × 3.1 × 15 mm3 each. The data acquisition system for the demonstrator has two Front End Boards type D (FEB/D), each collecting the data of 1'024 channels (8 DMs), and transmitting assembled data frames through a serial link (4.8 Gbps), to a single Data Acquisition (DAQ) board plugged into the Peripheral Component Interconnect Express (PCIe) bus of the data acquisition PC. Results obtained with this PET demonstrator are presented.

A LYSO crystal array readout by silicon photomultipliers as compact detector for space applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kryemadhi, A.; Barner, L.; Grove, A.

Precise measurements of GeV range gamma rays help narrow down among var- ious gamma emission models and increase sensitivity for dark matter searches. Construction of precise as well as compact instruments requires detectors with high efficiency, high stopping power, excellent energy resolution, and excellent angular resolution. Fast and bright crystal scintillators coupled with small foot- print photo-detectors are suitable candidates. We prototyped a detector array consisting of four LYSO crystals where each crystal is read out by a 2x2 SensL ArrayJ60035 silicon photomultipliers. The LYSO crystals were chosen because of their good light yield, fast decay time, demonstrated radiation hardness,more » and small radiation length. Here, we used the silicon photomultiplier arrays as photo- detectors because of their small size, simple readout, low voltage operation, and immunity to magnetic elds. We also studied the detector performance in the energy range of interest by exposing it to 2-16 GeV particles produced at the Test Beam Facility of Fermi National Accelerator Laboratory.« less

A LYSO crystal array readout by silicon photomultipliers as compact detector for space applications

DOE PAGES

Kryemadhi, A.; Barner, L.; Grove, A.; ...

2017-10-31

Precise measurements of GeV range gamma rays help narrow down among var- ious gamma emission models and increase sensitivity for dark matter searches. Construction of precise as well as compact instruments requires detectors with high efficiency, high stopping power, excellent energy resolution, and excellent angular resolution. Fast and bright crystal scintillators coupled with small foot- print photo-detectors are suitable candidates. We prototyped a detector array consisting of four LYSO crystals where each crystal is read out by a 2x2 SensL ArrayJ60035 silicon photomultipliers. The LYSO crystals were chosen because of their good light yield, fast decay time, demonstrated radiation hardness,more » and small radiation length. Here, we used the silicon photomultiplier arrays as photo- detectors because of their small size, simple readout, low voltage operation, and immunity to magnetic elds. We also studied the detector performance in the energy range of interest by exposing it to 2-16 GeV particles produced at the Test Beam Facility of Fermi National Accelerator Laboratory.« less

Rare earths, the lanthanides, yttrium and scandium

USGS Publications Warehouse

Bedinger, G.; Bleiwas, D.

2012-01-01

In 2011, rare earths were recovered from bastnasite concentrates at the Mountain Pass Mine in California. Consumption of refined rare-earth products decreased in 2011 from 2010. U.S. rare-earth imports originated primarily from China, with lesser amounts from Austria, Estonia, France and Japan. The United States imported all of its demand for yttrium metal and yttrium compounds, with most of it originating from China. Scandium was imported in various forms and processed domestically.

Highly efficient and high-power diode-pumped femtosecond Yb:LYSO laser

NASA Astrophysics Data System (ADS)

Tian, Wenlong; Wang, Zhaohua; Zhu, Jiangfeng; Zheng, Lihe; Xu, Jun; Wei, Zhiyi

2017-04-01

A diode-pumped high-power femtosecond Yb:LYSO laser with high efficiency is demonstrated. With a semiconductor saturable absorber mirror for passive mode-locking and a Gires-Tournois interferometer mirror for intracavity dispersion compensation, stable mode-locking pulses of 297 fs duration at 1042 nm were obtained. The maximum average power of 3.07 W was realized under 5.17 W absorbed pump power, corresponding to as high as 59.4% opt-opt efficiency. The single pulse energy and peak power are about 35.5 nJ and 119.5 kW, respectively.

Size-dependent cytotoxicity of yttrium oxide nanoparticles on primary osteoblasts in vitro

NASA Astrophysics Data System (ADS)

Zhou, Guoqiang; Li, Yunfei; Ma, Yanyan; Liu, Zhu; Cao, Lili; Wang, Da; Liu, Sudan; Xu, Wenshi; Wang, Wenying

2016-05-01

Yttrium oxide nanoparticles are an excellent host material for the rare earth metals and have high luminescence efficiency providing a potential application in photodynamic therapy and biological imaging. In this study, the effects of yttrium oxide nanoparticles with four different sizes were investigated using primary osteoblasts in vitro. The results demonstrated that the cytotoxicity generated by yttrium oxide nanoparticles depended on the particle size, and smaller particles possessed higher toxicological effects. For the purpose to elucidate the relationship between reactive oxygen species generation and cell damage, cytomembrane integrity, intracellular reactive oxygen species level, mitochondrial membrane potential, cell apoptosis rate, and activity of caspase-3 in cells were then measured. Increased reactive oxygen species level was also observed in a size-dependent way. Thus, our data demonstrated that exposure to yttrium oxide nanoparticles resulted in a size-dependent cytotoxicity in cultured primary osteoblasts, and reactive oxygen species generation should be one possible damage pathway for the toxicological effects produced by yttrium oxide particles. The results may provide useful information for more rational applications of yttrium oxide nanoparticles in the future.

Development of 2024 AA-Yttrium composites by Spark Plasma Sintering

NASA Astrophysics Data System (ADS)

Vidyasagar, CH S.; Karunakar, D. B.

2018-04-01

The method of fabrication of MMNCs is quite a challenge, which includes advanced processing techniques like Spark Plasma Sintering (SPS), etc. The objective of the present work is to fabricate aluminium based MMNCs with the addition of small amounts of yttrium using Spark Plasma Sintering and to evaluate their mechanical and microstructure properties. Samples of 2024 AA with yttrium ranging from 0.1% to 0.5 wt% are fabricated by Spark Plasma Sintering (SPS). Hardness of the samples is determined using Vickers hardness testing machine. The metallurgical characterization of the samples is evaluated by Optical Microscopy (OM), Field Emission Scanning Electron Microscopy (FE-SEM). Unreinforced 2024 AA sample is also fabricated as a benchmark to compare its properties with those of the composite developed. It is found that the yttrium addition increases the above mentioned properties by altering the precipitation kinetics and intermetallic formation to some extent and then decreases gradually when yttrium wt% increases beyond 0.3 wt%. High density (˂ 99.75) is achieved in the samples and highest hardness achieved is 114 Hv, fabricated by spark plasma sintering and uniform distribution of yttrium is observed.

Study the performance of LYSO and CeBr3 crystals using Silicon Photomultipliers

NASA Astrophysics Data System (ADS)

Kryemadhi, Abaz

2016-03-01

The Silicon Photomultipliers (SiPMs) are novel photon-detectors which have been progressively found their use in particle physics. Their small size, good single photon resolution, simple readout, and immunity to magnetic fields offers advantages compared to traditional photomultipliers. LYSO and CeBr3 crystals are relatively new scintillators with high light yield and fast decay time. The response of these detectors to low energy gamma rays and cosmic ray muons will be presented. Messiah College Workload Reallocation Program.

LYSO crystal testing for an EDM polarimeter

NASA Astrophysics Data System (ADS)

Müller, F.; Keshelashvili, I.; Mchedlishvili, D.; JEDI Collaboration

2017-11-01

Four detector modules, built from three different LYSO crystals and two different types of light sensors (PMTs and SiPM arrays), have been tested with a deuteron beam from 100 MeV - 270 MeV at the COSY accelerator facility for the srEDM project at the Forschungszentrum Jülich in Germany. The detector modules were arranged in a cluster hand mounted on a positioning table. The deuteron beam was targeted at the center of each individual crystal for data analysis. The signals were digitized using a 14 bit, 250 MS/s flash ADC. Further, the energy spectra were calibrated using the known beam energies from the accelerator. From the calibrated spectra, the energy resolution was calculated. A resolution of 3% for the low energies and down to 1% for the high energy of 270 MeV was achieved. A deuteron reconstruction efficiency of almost 100% for low energies and around 70% for high energies was achieved. The SiPM light sensor showed a very good performance and will be used for the next generation of detector modules.

Accumulation of radiation defects and products of radiolysis in lithium orthosilicate pebbles with silicon dioxide additions under action of high absorbed doses and high temperature in air and inert atmosphere

NASA Astrophysics Data System (ADS)

Zarins, A.; Supe, A.; Kizane, G.; Knitter, R.; Baumane, L.

2012-10-01

One of the technological problems of a fusion reactor is the change in composition and structure of ceramic breeders (Li4SiO4 or Li2TiO3 pebbles) during long-term operation. In this study changes in the composition and microstructure of Li4SiO4 pebbles with 2.5 wt% silicon dioxide additions, fabricated by a melt-spraying process, were investigated after fast electron irradiation (E = 5 MeV, dose rate up to 88 MGy h-1) with high absorbed dose from 1.3 to 10.6 GGy at high temperature (543-573 K) in air and argon atmosphere. Three types of pebbles with different diameters and grain sizes were investigated. Products of radiolysis were studied by means of FTIR and XRD. TSL and ESR spectroscopy were used to detect radiation defects. SEM was used to investigate structure of pebbles. Experiments showed that Li4SiO4 pebbles with a diameter of 500 μm had similar radiation stability as pebbles with diameter <50 μm which were annealed at 1173 K for 128 h in argon and air atmosphere. As well as determined that lithium orthosilicate pebbles with size 500 (1243 K 168 h) and <50 μm (1173 K 128 h) have a higher radiation stability in air and argon atmosphere than pebbles with size <50 μm (1073 K 1 h). Degree of decomposition α10.56 of the lithium orthosilicate pebbles at an absorbed dose of 10.56 GGy in air atmosphere is 1.5% and 0.15% at irradiation in dry argon. It has been suggested that changes of radiation stability of lithium orthosilicate pebbles in air atmosphere comparing with irradiated pebbles in argon atmosphere is effect of chemical reaction of lithium orthosilicate surface with air containing - H2O and CO2 in irradiation process. As well as it has been suggested that silicon dioxide - lithium metasilicate admixtures do not affect formation mechanism of radiation defect and products of radiolysis in lithium orthosilicate pebbles.

Hydrophilicity, photocatalytic activity and stability of tetraethyl orthosilicate modified TiO2 film on glazed ceramic surface

NASA Astrophysics Data System (ADS)

Zhang, Peng; Tian, Jie; Xu, Ruifen; Ma, Guojun

2013-02-01

A new, simple, and low-cost method has been developed to enhance the surface properties of TiO2 film. Degussa P25-TiO2 nanoparticles were modified by tetraethyl orthosilicate (TEOS) on glazed ceramic tiles. Effects of tetraethyl orthosilicate modification on microstructure, crystal structure, hydrophilicity, photocatalytic activity and stability of the film were investigated. The obtained results showed that P25-TiO2/TEOS particles exhibited better dispersion, higher surface area, bigger surface roughness and smaller particle size comparing to pure P25-TiO2 particles, which resulted in better hydrophilicity after 10 days in a dark place and higher photocatalytic activity under visible light irradiation. 68% of Rhodamine B was degraded by P25-TiO2/TEOS film in 25 h with the light intensity of 5000 ± 500 lx, and degradation rate reached to 82% with the light intensity of 10,000 ± 1000 lx. Furthermore, two fundamentally different systems, in which the films recycle for repetitive degradation after soaked in dye solution and for discoloration after depositing dye on the surfaces, respectively, were measured to confirm that P25-TiO2/TEOS film showed excellently stable performances. Therefore the P25-TiO2/TEOS film we obtained has good washing resistance and would be a promising candidate for practical applications.

Formation of Yttrium Oxysulfide Phosphor at Room Temperature

NASA Astrophysics Data System (ADS)

Shoji, Masahiko; Sakurai, Kenji

2005-12-01

Europium-doped yttrium oxysulfide (Y2O2S:Eu) phosphor was successfully synthesized at room temperature from yttrium oxide, europium oxide, and sulfur. The method employs high-energy ball milling to enable a substitution reaction between oxygen and sulfur, unlike conventional methods, such as heating in a sulfurizing atmosphere. It was found that the material is fluorescent through X-ray irradiation, and the luminescence spectra exhibit four peaks in the wavelength region from 500 to 800 nm.

Two-dimensional nuclear magnetic resonance structure determination module for introductory biochemistry: synthesis and structural characterization of lyso-glycerophospholipids.

PubMed

Garrett, Teresa A; Rose, Rebecca L; Bell, Sidney M

2013-01-01

In this laboratory module, introductory biochemistry students are exposed to two-dimensional (1) H-nuclear magnetic resonance of glycerophospholipids (GPLs). Working in groups of three, students enzymatically synthesized and purified a variety of 2-acyl lyso GPLs. The structure of the 2-acyl lyso GPL was verified using (1) H-correlation spectroscopy. Students scored significantly higher on an assessment of NMR knowledge after having participated in this lab module and in comparison to a similar cohort who did not participate. Inaddition, student confidence in their NMR knowledge and abilities increased 62% following the module and correlated with their ability to apply their NMR knowledge. Based on these results, the laboratory module was very effective at providing students with a more extensive understanding of the underlying concepts of NMR as a tool for structural determination. Copyright © 2013 International Union of Biochemistry and Molecular Biology, Inc.

Enhancement of Superconductivity of Lanthanum and Yttrium Sesquicarbide

DOEpatents

Krupka, M. C.; Giorgi, A. L.; Krikorian, N. H.; Szklarz, E. G.

1972-06-22

A method of enhancing the superconductivity of body-centered cubic lanthanum and yttrium sesquicarbide through formation of the sesquicarbides from ternary alloys of novel composition (N/sub x/M/sub 1-x/)C/sub z/, where N is yttrium or lanthanum, M is thorium, any of the Group IV and VI transition metals, or gold, germanium or silicon, and z is approximately 1.2 to 1.6. These ternary sesquicarbides have superconducting transition temperatures as high as 17.0/sup 0/K.

Enhancement of superconductivity of lanthanum and yttrium sesquicarbide

DOEpatents

Krupka, M.C.; Giorgi, A.L.; Krikorian, N.H.; Szklarz, E.G.

1971-06-22

A method of enhancing the superconductivity of body-centered cubic lanthanum and yttrium sesquicarbide through formation of the sesquicarbides from ternary alloys of novel composition (N/sub x/M/sub 1-x/)C/sub z/, where N is yttrium or lanthanum, M is thorium, any of the Group IV and VI transition metals, or gold, germanium or silicon, and z is approximately 1.2 to 1.6. These ternary sesquicarbides have superconducting transition temperatures as high as 17.0/sup 0/K.

LysoPC-acyl C16:0 is associated with brown adipose tissue activity in men.

PubMed

Boon, Mariëtte R; Bakker, Leontine E H; Prehn, Cornelia; Adamski, Jerzy; Vosselman, Maarten J; Jazet, Ingrid M; Arias-Bouda, Lenka M Pereira; van Lichtenbelt, Wouter D Marken; van Dijk, Ko Willems; Rensen, Patrick C N; Mook-Kanamori, Dennis O

2017-01-01

Brown adipose tissue (BAT) recently emerged as a potential therapeutic target in the treatment of obesity and associated disorders due to its fat-burning capacity. The current gold standard in assessing BAT activity is [ 18 F]FDG PET-CT scan, which has severe limitations including radiation exposure, being expensive, and being labor-intensive. Therefore, indirect markers are needed of human BAT activity and volume. We aimed to identify metabolites in serum that are associated with BAT volume and activity in men. We assessed 163 metabolites in fasted serum of a cohort of twenty-two healthy lean men (age 24.1 (21.7-26.6) years, BMI 22.1 (20.5-23.4) kg/m 2 ) who subsequently underwent a cold-induced [ 18 F]FDG PET-CT scan to assess BAT volume and activity. In addition, we included three replication cohorts consisting of in total thirty-seven healthy lean men that were similar with respect to age and BMI compared to the discovery cohort. After correction for multiple testing, fasting concentrations of lysophosphatidylcholine-acyl (LysoPC-acyl) C16:1, LysoPC-acyl C16:0 and phosphatidylcholine-diacyl C32:1 showed strong positive correlations with BAT volume (β= 116 (85-148) mL, R 2  = 0.81, p = 4.6 × 10 -7 ; β = 79 (93-119) mL, R 2  = 0.57, p = 5.9 × 10 -4 and β= 91 (40-141) mL, R 2  = 0.52, p = 1.0 × 10 -3 , respectively) as well as with BAT activity (β= 0.20 (0.11-0.29) g/mL, R 2  = 0.59, p = 1.9 × 10 -4 ; β = 0.15 (0.06-0.23) g/mL, R 2  = 0.47, p = 2.0 × 10 -3 and β= 0.13 (0.01-0.25) g/mL, R 2  = 0.28, p = 0.04, respectively). When tested in three independent replication cohorts (total n = 37), the association remained significant between LysoPC-acyl C16:0 and BAT activity in a pooled analysis (β= 0.15 (0.07-0.23) g/mL, R 2  = 0.08, p = 4.2 × 10 -4 ). LysoPC-acyl C16:0 is associated with BAT activity in men. Since BAT is regarded as a promising tool in

Production and characterization of europium doped sol-gel yttrium oxide

NASA Astrophysics Data System (ADS)

Krebs, J. K.; Hobson, Christopher; Silversmith, Ann

2004-03-01

Sol-gel produced materials have recently gained attention for their use in producing nanoscale dielectric materials for confinement studies. Lanthanide impurities in the dielectric enable experimenters to optically probe the structure and dynamic properties of the nanoparticle hosts. We report on an alkoxide sol-gel production method used to produce trivalent europium doped yttrium oxide. Our process follows the standard hydrolysis of an alkoxide precursor with water containing the lanthanide ions. The sol is then aged and calcined at 800 ^oC to produce the powder samples. X-ray diffraction confirms the structure of the powder is that of Y_2O_3. The emission and excitation of the europium impurities is consistent with that of europium doped single crystal yttrium oxide, where it is known that the europium ions substitute for yttrium in the lattice. We therefore conclude that the sol-gel process enables the incorporation of europium ions into the yttrium oxide structure at temperatures far below the melting temperature. The results of preliminary dynamics measurements will also be discussed.

The behaviour of selected yttrium containing bioactive glass microspheres in simulated body environments.

PubMed

Cacaina, D; Ylänen, H; Simon, S; Hupa, M

2008-03-01

The study aims at the manufacture and investigation of biodegradable glass microspheres incorporated with yttrium potentially useful for radionuclide therapy of cancer. The glass microspheres in the SiO2-Na2O-P2O5-CaO-K2O-MgO system containing yttrium were prepared by conventional melting and flame spheroidization. The behaviour of the yttrium silicate glass microspheres was investigated under in vitro conditions using simulated body fluid (SBF) and Tris buffer solution (TBS), for different periods of time, according to half-life time of the Y-90. The local structure of the glasses and the effect of yttrium on the biodegradability process were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy and Back Scattered Electron Imaging of Scanning Electron Microscopy (BEI-SEM) equipped with Energy Dispersive X-ray (EDX) analysis. UV-VIS spectrometry and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used for analyzing the release behaviour of silica and yttrium in the two used solutions. The results indicate that the addition of yttrium to a bioactive glass increases its structural stability which therefore, induced a different behaviour of the glasses in simulated body environments.

Electronic structure and electron-phonon interaction in hexagonal yttrium by density functional calculations

NASA Astrophysics Data System (ADS)

Singh, Prabhakar P.

2007-03-01

To understand the pressure-induced changes in the electronic structure and the electron-phonon interaction in yttrium, we have studied hexagonal-close-packed (hcp) yttrium, stable at ambient pressure, and double hexagonal-close-packed (dhcp) yttrium, stable up to around 44GPa , using density-functional-based methods. Our results show that as one goes from hcp yttrium to dhcp yttrium, there are (i) a substantial charge transfer from s→d with extensive modifications of the d band and a sizable reduction in the density of states at the Fermi energy, (ii) a substantial stiffening of phonon modes with the electron-phonon coupling covering the entire frequency range, and (iii) an increase in the electron-phonon coupling constant λ from 0.55 to 1.24, leading to a change in the superconducting transition temperature Tc from 0.3to15.3K for μ*=0.2 .

Alkali metal yttrium neo-pentoxide double alkoxide precursors to alkali metal yttrium oxide nanomaterials

DOE PAGES

Boyle, Timothy J.; Neville, Michael L.; Sears, Jeremiah Matthew; ...

2016-03-15

In this study, a series of alkali metal yttrium neo-pentoxide ([AY(ONep) 4]) compounds were developed as precursors to alkali yttrium oxide (AYO 2) nanomaterials. The reaction of yttrium amide ([Y(NR 2) 3] where R=Si(CH 3) 3) with four equivalents of H-ONep followed by addition of [A(NR 2)] (A=Li, Na, K) or A o (A o=Rb, Cs) led to the formation of a complex series of A nY(ONep) 3+n species, crystallographically identified as [Y 2Li 3(μ 3-ONep)(μ 3-HONep)(μ-ONep) 5(ONep) 3(HONep) 2] (1), [YNa 2(μ 3-ONep) 4(ONep)] 2 (2), {[Y 2K 3(μ 3-ONep) 3(μ-ONep) 4(ONep) 2(ηξ-tol) 2][Y 4K 2(μ 4-O)(μ 3-ONep) 8(ONep)more » 4]•η x-tol]} (3), [Y 4K 2(μ 4-O)(μ 3-ONep) 8(ONep) 4] (3a), [Y 2Rb 3(μ 4-ONep) 3(μ-ONep) 6] (4), and [Y 2Cs 4(μ 6-O)(μ 3-ONep) 6(μ 3-HONep) 2(ONep) 2(η x-tol) 4]•tol (5). Compounds 1–5 were investigated as single source precursors to AYOx nanomaterials following solvothermal routes (pyridine, 185 °C for 24h). The final products after thermal processing were found by powder X-ray diffraction experiments to be Y 2O 3 with variable sized particles based on transmission electron diffraction. Energy dispersive X-ray spectroscopy studies indicated that the heavier alkali metal species were present in the isolated nanomaterials.« less

Evidence of yttrium silicate inclusions in YSZ-porcelain veneers.

PubMed

Stoner, Brian R; Griggs, Jason A; Neidigh, John; Piascik, Jeffrey R

2014-04-01

This report introduces the discovery of crystalline defects that can form in the porcelain veneering layer when in contact with yttria-stabilized zirconia (YSZ). The focus was on dental prostheses and understanding the defects that form in the YSZ/porcelain system; however the data reported herein may have broader implications toward the use and stability of YSZ-based ceramics in general. Specimens were cut from fully sintered YSZ plates and veneering porcelain was applied (<1 mm thick) to one surface and fired under manufacturer's recommended protocol. Scanning electron microscopy (SEM) with integrated electron dispersive X-ray (EDAX) was used for microstructural and elemental analysis. EDAX, for chemical analysis and transmission electron diffraction (TED) for structural analysis were both performed in the transmission electron microscope (TEM). Additionally, in order to spatially resolve Y-rich precipitates, micro-CT scans were conducted at varying depths within the porcelain veneer. Local EDAX (SEM) was performed in the regions of visible inclusions and showed significant increases in yttrium concentration. TEM specimens also showed apparent inclusions in the porcelain and selected area electron diffraction was performed on these regions and found the inclusions to be crystalline and identified as either yttrium-silicate (Y2 SiO5 ) or yttrium-disilicate (Y2 Si2 O7 ). Micro-CT data showed that yttrium-silicate precipitates were distributed throughout the thickness of the porcelain veneer. Future studies are needed to determine whether many of the premature failures associated with this materials system may be the result of crystalline flaws that form as a result of high temperature yttrium diffusion near the surfaces of YSZ. © 2013 Wiley Periodicals, Inc.

Metabolomics analysis identifies sex-associated metabotypes of oxidative stress and the autotaxin–lysoPA axis in COPD

PubMed Central

Naz, Shama; Kolmert, Johan; Yang, Mingxing; Reinke, Stacey N.; Kamleh, Muhammad Anas; Snowden, Stuart; Heyder, Tina; Levänen, Bettina; Erle, David J.; Sköld, C. Magnus; Wheelock, Åsa M.; Wheelock, Craig E.

2017-01-01

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease and a leading cause of mortality and morbidity worldwide. The aim of this study was to investigate the sex dependency of circulating metabolic profiles in COPD. Serum from healthy never-smokers (healthy), smokers with normal lung function (smokers), and smokers with COPD (COPD; Global Initiative for Chronic Obstructive Lung Disease stages I–II/A–B) from the Karolinska COSMIC cohort (n=116) was analysed using our nontargeted liquid chromatography–high resolution mass spectrometry metabolomics platform. Pathway analyses revealed that several altered metabolites are involved in oxidative stress. Supervised multivariate modelling showed significant classification of smokers from COPD (p=2.8×10−7). Sex stratification indicated that the separation was driven by females (p=2.4×10−7) relative to males (p=4.0×10−4). Significantly altered metabolites were confirmed quantitatively using targeted metabolomics. Multivariate modelling of targeted metabolomics data confirmed enhanced metabolic dysregulation in females with COPD (p=3.0×10−3) relative to males (p=0.10). The autotaxin products lysoPA (16:0) and lysoPA (18:2) correlated with lung function (forced expiratory volume in 1 s) in males with COPD (r=0.86; p<0.0001), but not females (r=0.44; p=0.15), potentially related to observed dysregulation of the miR-29 family in the lung. These findings highlight the role of oxidative stress in COPD, and suggest that sex-enhanced dysregulation in oxidative stress, and potentially the autotaxin–lysoPA axis, are associated with disease mechanisms and/or prevalence. PMID:28642310

Yttrium and rare earth stabilized fast reactor metal fuel

DOEpatents

Guon, Jerold; Grantham, LeRoy F.; Specht, Eugene R.

1992-01-01

To increase the operating temperature of a reactor, the melting point and mechanical properties of the fuel must be increased. For an actinide-rich fuel, yttrium, lanthanum and/or rare earth elements can be added, as stabilizers, to uranium and plutonium and/or a mixture of other actinides to raise the melting point of the fuel and improve its mechanical properties. Since only about 1% of the actinide fuel may be yttrium, lanthanum, or a rare earth element, the neutron penalty is low, the reactor core size can be reduced, the fuel can be burned efficiently, reprocessing requirements are reduced, and the nuclear waste disposal volumes reduced. A further advantage occurs when yttrium, lanthanum, and/or other rare earth elements are exposed to radiation in a reactor, they produce only short half life radioisotopes, which reduce nuclear waste disposal problems through much shorter assured-isolation requirements.

Recovery of yttrium from fluorescent powder of cathode ray tube, CRT: Zn removal by sulphide precipitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Innocenzi, Valentina, E-mail: valentina.innocenzi1@univaq.it; De Michelis, Ida; Ferella, Francesco

2013-11-15

Highlights: • Treatment of fluorescent powder of CRT waste. • Factorial experimental designs to study acid leaching of fluorescent powder and the purification of leach liquors. • Recover of yttrium by precipitation using oxalic acid. • Suitable flowsheet to recover yttrium from fluorescent powder. - Abstract: This work is focused on the recovery of yttrium and zinc from fluorescent powder of cathode ray tube (CRT). Metals are extracted by sulphuric acid in the presence of hydrogen peroxide. Leaching tests are carried out according to a 2{sup 2} full factorial plan and the highest extraction yields for yttrium and zinc equalmore » to 100% are observed under the following conditions: 3 M of sulphuric acid, 10% v/v of H{sub 2}O{sub 2} concentrated solution at 30% v/v, 10% w/w pulp density, 70 °C and 3 h of reaction. Two series of precipitation tests for zinc are carried out: a 2{sup 2} full factorial design and a completely randomized factorial design. In these series the factors investigated are pH of solution during the precipitation and the amount of sodium sulphide added to precipitate zinc sulphide. The data of these tests are used to describe two empirical mathematical models for zinc and yttrium precipitation yields by regression analysis. The highest precipitation yields for zinc are obtained under the following conditions: pH equal to 2–2.5% and 10–12% v/v of Na{sub 2}S concentrated solution at 10% w/v. In these conditions the coprecipitation of yttrium is of 15–20%. Finally further yttrium precipitation experiments by oxalic acid on the residual solutions, after removing of zinc, show that yttrium could be recovered and calcined to obtain the final product as yttrium oxide. The achieved results allow to propose a CRT recycling process based on leaching of fluorescent powder from cathode ray tube and recovery of yttrium oxide after removing of zinc by precipitation. The final recovery of yttrium is 75–80%.« less

Recovery of yttrium from cathode ray tubes and lamps’ fluorescent powders: experimental results and economic simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Innocenzi, V., E-mail: valentina.innocenzi1@univaq.it; De Michelis, I.; Ferella, F.

2013-11-15

Highlights: • Fluorescent powder of lamps. • Fluorescent powder of cathode ray rubes. • Recovery of yttrium from fluorescent powders. • Economic simulation for the processes to recover yttrium from WEEE. - Abstract: In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides. Experimental results have shown that process conditions necessary tomore » purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%. Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes.« less

Selective liquid chromatographic separation of yttrium from heavier rare earth elements using acetic acid as a novel eluent.

PubMed

Kifle, Dejene; Wibetoe, Grethe

2013-09-13

One of the major difficulties in the rare earth elements separation is purification of yttrium from heavy rare earth elements. Thus, an HPLC method using acetic acid as novel eluent was explored for selective separation of yttrium form the heavy rare earth elements. When acetic acid is used as a mobile phase yttrium eluted with the lighter lanthanides. This is contrary to its relative position amongst heavier lanthanides when eluents commonly used for separation of rare earth elements were employed. The shift in elution position of yttrium with acetic acid as eluent may reflect a relatively lower stability constant of the yttrium-AcOH complex (in the same order as for the lighter lanthanides) compared to the corresponding AcOH complexes with heavy lanthanides, enabling selective separation of yttrium from the latter. The method was successfully used for selective separation of yttrium in mixed rare earth sample containing about 80% of yttrium and about 20% of heavy rare earth oxides. Thus, the use of AcOH as eluent is an effective approach for separating and determining the trace amounts of heavy rare earth elements in large amounts of yttrium matrix. Separation was performed on C18 column by running appropriate elution programs. The effluent from the column was monitored with diode array detector at absorbance wavelength of 658nm after post column derivatization with Arsenazo III. Copyright © 2013 Elsevier B.V. All rights reserved.

Tunable femtosecond near-infrared source based on a Yb:LYSO-laser-pumped optical parametric oscillator

NASA Astrophysics Data System (ADS)

Wen-Long, Tian; Zhao-Hua, Wang; Jiang-Feng, Zhu; Zhi-Yi, Wei

2016-01-01

We demonstrate a widely tunable near-infrared source from 767 nm to 874 nm generated by the intracavity second harmonic generation (SHG) in an optical parametric oscillator pumped by a Yb:LYSO solid-state laser. The home-made Yb:LYSO oscillator centered at 1035 nm delivers an average power of 2 W and a pulse duration as short as 351 fs. Two MgO doped periodically poled lithium niobates (MgO:PPLN) with grating periods of 28.5-31.5 μm in steps of 0.5 μm and 19.5-21.3 μm in steps of 0.2 μm are used for the OPO and intracavity SHG, respectively. The maximum average output power of 180 mW at 798 nm was obtained and the output pulses have pulse duration of 313 fs at 792 nm if a sech2-pulse shape was assumed. In addition, tunable signal femtosecond pulses from 1428 nm to 1763 nm are also realized with the maximum average power of 355 mW at 1628 nm. Project supported by the National Key Basic Research Program of China (Grant No. 2013CB922402), the National Key Scientific Instruments Development Program of China (Grant No. 2012YQ120047), the National Natural Science Foundation of China (Grant Nos. 61205130 and 11174361), and the Key Deployment Project of Chinese Academy of Sciences (Grant No. KJZD-EW-L11-03).

Holmium: yttrium aluminum garnet laser-assisted endoscopic sinus surgery: laboratory experience.

PubMed

Shapshay, S M; Rebeiz, E E; Bohigian, R K; Hybels, R L; Aretz, H T; Pankratov, M M

1991-02-01

Endoscopic sinus surgery has gained wide acceptance since its introduction into the United States. Complex sinus anatomy and troublesome bleeding have been associated with complications, which vary in severity from synechia to blindness and leakage of cerebrospinal fluid. Endoscopic sinus surgery using a holmium: yttrium aluminum garnet pulsed solid-state laser oscillating at 2.1 microns with fiberoptic delivery was performed in the laboratory, and the results were compared with those of conventional endoscopic sinus surgery. Three beagle dogs, six human cadaver heads, and one calf head were used in the in vivo and in vitro studies to evaluate the bone ablation, tissue coagulation, and hemostatic properties of the holmium: yttrium aluminum garnet laser. Modified endoscopic telescopes for sinus surgery, a newly developed handpiece for fiberoptic delivery, and other surgical instruments were used. The results indicate that the holmium: yttrium aluminum garnet laser and new delivery instrumentation provide good hemostasis and controlled soft-tissue ablation and bone removal. The access to all sinuses in the human cadaver model was very good. The canine in vivo study showed delayed but complete healing on the laser-treated side. Clinical evaluation of the holmium: yttrium aluminum garnet laser is warranted to increase the precision and safety of endoscopic sinus surgery.

Monte carlo simulations of Yttrium reaction rates in Quinta uranium target

NASA Astrophysics Data System (ADS)

Suchopár, M.; Wagner, V.; Svoboda, O.; Vrzalová, J.; Chudoba, P.; Tichý, P.; Kugler, A.; Adam, J.; Závorka, L.; Baldin, A.; Furman, W.; Kadykov, M.; Khushvaktov, J.; Solnyshkin, A.; Tsoupko-Sitnikov, V.; Tyutyunnikov, S.; Bielewicz, M.; Kilim, S.; Strugalska-Gola, E.; Szuta, M.

2017-03-01

The international collaboration Energy and Transmutation of Radioactive Waste (E&T RAW) performed intensive studies of several simple accelerator-driven system (ADS) setups consisting of lead, uranium and graphite which were irradiated by relativistic proton and deuteron beams in the past years at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The most recent setup called Quinta, consisting of natural uranium target-blanket and lead shielding, was irradiated by deuteron beams in the energy range between 1 and 8 GeV in three accelerator runs at JINR Nuclotron in 2011 and 2012 with yttrium samples among others inserted inside the setup to measure the neutron flux in various places. Suitable activation detectors serve as one of possible tools for monitoring of proton and deuteron beams and for measurements of neutron field distribution in ADS studies. Yttrium is one of such suitable materials for monitoring of high energy neutrons. Various threshold reactions can be observed in yttrium samples. The yields of isotopes produced in the samples were determined using the activation method. Monte Carlo simulations of the reaction rates leading to production of different isotopes were performed in the MCNPX transport code and compared with the experimental results obtained from the yttrium samples.

Etudes optiques de nouveaux materiaux laser: Des orthosilicates dopes a l'ytterbium: Le yttrium (lutetium,scandium) pentoxide de silicium

NASA Astrophysics Data System (ADS)

Denoyer, Aurelie

La decouverte et l'elaboration de nouveaux materiaux laser solides suscitent beaucoup d'interet parmi la communaute scientifique. En particulier les lasers dans la gamme de frequence du micron debouchent sur beaucoup d'applications, en telecommunication, en medecine, dans le domaine militaire, pour la, decoupe des metaux (lasers de puissance), en optique non lineaire (doublage de frequence, bistabilite optique). Le plus couramment utilise actuellement est le Nd:YAG dans cette famille de laser, mais des remplacants plus performants sont toujours recherches. Les lasers a base d'Yb3+ possedent beaucoup d'avantages compares aux lasers Nd3+ du fait de leur structure electronique simple et de leur deterioration moins rapide. Parmi les matrices cristallines pouvant accueillir l'ytterbium, les orthosilicates Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5 se positionnent tres bien, du fait de leur bonne conductivite thermique et du fort eclatement de leur champ cristallin necessaire a l'elaboration de lasers quasi-3 niveaux. De plus l'etude fine et systematique des proprietes microscopiques de nouveaux materiaux s'avere toujours tres interessante du point de vue de la recherche fondamentale, c'est ainsi que de nouveaux modeles sont concus (par exemple pour le champ cristallin) ou que de nouvelles proprietes inhabituelles sont decouvertes, menant a de nouvelles applications. Ainsi d'autres materiaux dopes a l'ytterbium sont connus pour leurs proprietes de couplage electron-phonon, de couplage magnetique, d'emission cooperative ou encore de bistabilite optique, mais ces proprietes n'ont encore jamais ete mises en evidence dans Yb:Y 2SiO5, Yb:Lu2SiO5 et Yb:Sc2SiO 5. Ainsi, cette these a pour but l'etude des proprietes optiques et des interactions microscopiques dans Yb:Y2SiO 5, Yb:Lu2SiO5 et Yb:Sc2SiO5. Nous utilisons principalement les techniques d'absorption IR et de spectroscopie Raman pour determiner les excitations du champ cristallin et les modes de vibration dans le materiau

Comparison between Pixelated Scintillators: CsI(Tl), LaCl 3(Ce) and LYSO(Ce) when coupled to a Silicon Photomultipliers Array

NASA Astrophysics Data System (ADS)

Jeong, Manhee; Van, Benjamin; Wells, Byron T.; D'Aries, Lawrence J.; Hammig, Mark D.

2018-06-01

A large area SiPM array is individually coupled to five different types of scintillators in and each is evaluated for the development of a coded aperture imaging system. In order to readout signals from the 144 pixel array, a resistor network with symmetric charge division circuitry was developed, which successfully provides a significant reduction in the multiplicity of the analog outputs and reduces the size of the accumulated data. Energy resolutions at 662 keV for pixelated arrays of dimensions and material types as follows: 3 × 3 × 20 mm3 CsI(Tl), 4 × 4 × 20 mm3 CsI(Tl), 4 × 4 × 5 mm3 LYSO(Ce), 4 × 4 × 10 mm3 LYSO(Ce), and 2 × 2 × 5 mm3 LaCl3(Ce) have been determined. In addition, sub-millimeter FWHM pixel-identification resolutions were acquired from all of the scintillators tested.

Synthesis of aluminum-based scandium-yttrium master alloys

NASA Astrophysics Data System (ADS)

Bazhin, V. Yu.; Kosov, Ya. I.; Lobacheva, O. L.; Dzhevaga, N. V.

2015-07-01

The preparation technology for an Al-2% Sc-0.5% Y master alloy using aluminum-manganese alloys has been developed and tested. The microstructure of the prepared master alloy is studied and the compositions of intermetallics is determined. The efficient technological parameters of the synthesis are determined. It is shown that varying the compositions of starting reagents and alloying additions and optimizing the process conditions (temperature, mixing, etc.) allow us to forecast the manufacturing and operating characteristics of aluminum-based master alloys. Joint additions of scandium and yttrium oxides to a charge favor a substantial decrease in the grain size of the formed intermetallics; this effect appears to the utmost in the case of microallying with yttrium up to 0.5 wt %.

Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

PubMed Central

Bircher, Chad; Shao, Yiping

2012-01-01

Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators’ internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 × 1.5 and 2.0 × 2.0 mm2 cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be

A prototype MR insertable brain PET using tileable GAPD arrays.

PubMed

Hong, Key Jo; Choi, Yong; Jung, Jin Ho; Kang, Jihoon; Hu, Wei; Lim, Hyun Keong; Huh, Yoonsuk; Kim, Sangsu; Jung, Ji Woong; Kim, Kyu Bom; Song, Myung Sung; Park, Hyun-Wook

2013-04-01

The aim of this study was to develop a prototype magnetic resonance (MR)-compatible positron emission tomography (PET) that can be inserted into a MR imager and that allows simultaneous PET and MR imaging of the human brain. This paper reports the initial results of the authors' prototype brain PET system operating within a 3-T magnetic resonance imaging (MRI) system using newly developed Geiger-mode avalanche photodiode (GAPD)-based PET detectors, long flexible flat cables, position decoder circuit with high multiplexing ratio, and digital signal processing with field programmable gate array-based analog to digital converter boards. A brain PET with 72 detector modules arranged in a ring was constructed and mounted in a 3-T MRI. Each PET module was composed of cerium-doped lutetium yttrium orthosilicate (LYSO) crystals coupled to a tileable GAPD. The GAPD output charge signals were transferred to preamplifiers using 3 m long flat cables. The LYSO and GAPD were located inside the MR bore and all electronics were positioned outside the MR bore. The PET detector performance was investigated both outside and inside the MRI, and MR image quality was evaluated with and without the PET system. The performance of the PET detector when operated inside the MRI during MR image acquisition showed no significant change in energy resolution and count rates, except for a slight degradation in timing resolution with an increase from 4.2 to 4.6 ns. Simultaneous PET/MR images of a hot-rod and Hoffman brain phantom were acquired in a 3-T MRI. Rods down to a diameter of 3.5 mm were resolved in the hot-rod PET image. The activity distribution patterns between the white and gray matter in the Hoffman brain phantom were well imaged. The hot-rod and Hoffman brain phantoms on the simultaneously acquired MR images obtained with standard sequences were observed without any noticeable artifacts, although MR image quality requires some improvement. These results demonstrate that the

Radioembolization and the Dynamic Role of 90Y PET/CT

PubMed Central

Pasciak, Alexander S.; Bourgeois, Austin C.; McKinney, J. Mark; Chang, Ted T.; Osborne, Dustin R.; Acuff, Shelley N.; Bradley, Yong C.

2014-01-01

Before the advent of tomographic imaging, it was postulated that decay of 90 Y to the 0+ excited state of 90Zr may result in emission of a positron–electron pair. While the branching ratio for pair-production is small (~32 × 10−6), PET has been successfully used to image 90 Y in numerous recent patients and phantom studies. 90 Y PET imaging has been performed on a variety of PET/CT systems, with and without time-of-flight (TOF) and/or resolution recovery capabilities as well as on both bismuth-germanate and lutetium yttrium orthosilicate (LYSO)-based scanners. On all systems, resolution and contrast superior to bremsstrahlung SPECT has been reported. The intrinsic radioactivity present in LYSO-based PET scanners is a potential limitation associated with accurate quantification of 90 Y. However, intrinsic radioactivity has been shown to have a negligible effect at the high activity concentrations common in 90 Y radioembolization. Accurate quantification is possible on a variety of PET scanner models, with or without TOF, although TOF improves accuracy at lower activity concentrations. Quantitative 90 Y PET images can be transformed into 3-dimensional (3D) maps of absorbed dose based on the premise that the 90 Y activity distribution does not change after infusion. This transformation has been accomplished in several ways, although the most common is with the use of 3D dose-point-kernel convolution. From a clinical standpoint, 90 Y PET provides a superior post-infusion evaluation of treatment technical success owing to its improved resolution. Absorbed dose maps generated from quantitative PET data can be used to predict treatment efficacy and manage patient follow-up. For patients who receive multiple treatments, this information can also be used to provide patient-specific treatment-planning for successive therapies, potentially improving response. The broad utilization of 90 Y PET has the potential to provide a wealth of dose�

Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout.

PubMed

Bircher, Chad; Shao, Yiping

2012-02-01

Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 × 1.5 and 2.0 × 2.0 mm(2) cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. The internal radioactivity of LYSO scintillators can be used to accurately measure DOI function

Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bircher, Chad; Shao Yiping

Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method couldmore » be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm{sup 2} cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can

Sol-Gel Synthesis and Antioxidant Properties of Yttrium Oxide Nanocrystallites Incorporating P-123.

PubMed

Mellado-Vázquez, Rebeca; García-Hernández, Margarita; López-Marure, Arturo; López-Camacho, Perla Yolanda; de Jesús Morales-Ramírez, Ángel; Beltrán-Conde, Hiram Isaac

2014-09-19

Yttrium oxide (Y₂O₃) nanocrystallites were synthesized by mean of a sol-gel method using two different precursors. Raw materials used were yttrium nitrate and yttrium chloride, in methanol. In order to promote oxygen vacancies, P-123 poloxamer was incorporated. Synthesized systems were heat-treated at temperatures from 700 °C to 900 °C. Systems at 900 °C were prepared in the presence and absence of P-123 using different molar ratios (P-123:Y = 1:1 and 2:1). Fourier transform infrared spectroscopy (FTIR) results revealed a characteristic absorption band of Y-O vibrations typical of Y₂O₃ matrix. The structural phase was analyzed by X-ray diffraction (XRD), showing the characteristic cubic phase in all systems. The diffraction peak that presented the major intensity corresponded to the sample prepared from yttrium chloride incorporating P-123 in a molar ratio of P-123:Y = 2:1 at 900 °C. Crystallites sizes were determined by Scherrer equation as between 21 nm and 32 nm. Antioxidant properties were estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assays; the results are discussed.

Evaluation of acridine orange, LysoTracker Red, and quinacrine as fluorescent probes for long-term tracking of acidic vesicles.

PubMed

Pierzyńska-Mach, Agnieszka; Janowski, Paweł A; Dobrucki, Jurek W

2014-08-01

Acidic vesicles can be imaged and tracked in live cells after staining with several low molecular weight fluorescent probes, or with fluorescently labeled proteins. Three fluorescent dyes, acridine orange, LysoTracker Red DND-99, and quinacrine, were evaluated as acidic vesicle tracers for confocal fluorescence imaging and quantitative analysis. The stability of fluorescent signals, achievable image contrast, and phototoxicity were taken into consideration. The three tested tracers exhibit different advantages and pose different problems in imaging experiments. Acridine orange makes it possible to distinguish acidic vesicles with different internal pH but is fairly phototoxic and can cause spectacular bursts of the dye-loaded vesicles. LysoTracker Red is less phototoxic but its rapid photobleaching limits the range of useful applications considerably. We demonstrate that quinacrine is most suitable for long-term imaging when a high number of frames is required. This capacity made it possible to trace acidic vesicles for several hours, during a process of drug-induced apoptosis. An ability to record the behavior of acidic vesicles over such long periods opens a possibility to study processes like autophagy or long-term effects of drugs on endocytosis and exocytosis. © 2014 International Society for Advancement of Cytometry.

The Influence of Yttrium on High Temperature Oxidation of Valve Steels

NASA Astrophysics Data System (ADS)

Grzesik, Z.; Migdalska, M.; Mrowec, S.

2015-04-01

The influence of small amounts of yttrium, electrochemically deposited on the surface of four steels utilized in the production of valves in car engines, on the protective properties of the oxide scale and its adherence to the surface of the oxidized materials has been studied under isothermal and thermal cycle conditions. Oxidation measurements have been carried out at 1173 K. It has been found that yttrium addition improves considerably the scale adherence to the substrate surface, increasing thereby corrosion resistance of the studied materials.

Reactions of calcium orthosilicate and barium zirconate with oxides and sulfates of various elements

NASA Technical Reports Server (NTRS)

Zaplatynsky, I.

1979-01-01

Calcium orthosilicate and barium zirconate were evaluated as the insulation layer of thermal barrier coatings for air cooled gas turbine components. Their reactions with various oxides and sulfates were studied at 1100 C and 1300 C for times ranging up to 400 and 200 hours, respectively. These oxides and sulfates represent potential impurities or additives in gas turbine fuels and in turbine combustion air, as well as elements of potential bond coat alloys. The phase compositions of the reaction products were determined by X-ray diffraction analysis. BaZrO3 and 2CaO-SiO2 both reacted with P2O5, V2O5, Cr2O3, Al2O3, and SiO2. In addition, 2CaO-SiO2 reacted with Na2O, BaO, MgO, and CoO and BaZrO3 reacted with Fe2O3.

Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Innocenzi, Valentina, E-mail: valentina.innocenzi1@univaq.it; De Michelis, Ida; Kopacek, Bernd

2014-07-15

Highlights: • Review of the main hydrometallurgical processes to recover yttrium. • Recovery of yttrium from primary sources. • Recovery of yttrium from e-waste and other types of waste. - Abstract: Yttrium is important rare earths (REs) used in numerous fields, mainly in the phosphor powders for low-energy lighting. The uses of these elements, especially for high-tech products are increased in recent years and combined with the scarcity of the resources and the environmental impact of the technologies to extract them from ores make the recycling waste, that contain Y and other RE, a priority. The present review summarized themore » main hydrometallurgical technologies to extract Y from ores, contaminated solutions, WEEE and generic wastes. Before to discuss the works about the treatment of wastes, the processes to retrieval Y from ores are discussed, since the processes are similar and derived from those already developed for the extraction from primary sources. Particular attention was given to the recovery of Y from WEEE because the recycle of them is important not only for economical point of view, considering its value, but also for environmental impact that this could be generated if not properly disposal.« less

Sol-Gel Synthesis and Antioxidant Properties of Yttrium Oxide Nanocrystallites Incorporating P-123

PubMed Central

Mellado-Vázquez, Rebeca; García-Hernández, Margarita; López-Marure, Arturo; López-Camacho, Perla Yolanda; Morales-Ramírez, Ángel de Jesús; Beltrán-Conde, Hiram Isaac

2014-01-01

Yttrium oxide (Y2O3) nanocrystallites were synthesized by mean of a sol-gel method using two different precursors. Raw materials used were yttrium nitrate and yttrium chloride, in methanol. In order to promote oxygen vacancies, P-123 poloxamer was incorporated. Synthesized systems were heat-treated at temperatures from 700 °C to 900 °C. Systems at 900 °C were prepared in the presence and absence of P-123 using different molar ratios (P-123:Y = 1:1 and 2:1). Fourier transform infrared spectroscopy (FTIR) results revealed a characteristic absorption band of Y–O vibrations typical of Y2O3 matrix. The structural phase was analyzed by X-ray diffraction (XRD), showing the characteristic cubic phase in all systems. The diffraction peak that presented the major intensity corresponded to the sample prepared from yttrium chloride incorporating P-123 in a molar ratio of P-123:Y = 2:1 at 900 °C. Crystallites sizes were determined by Scherrer equation as between 21 nm and 32 nm. Antioxidant properties were estimated by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assays; the results are discussed. PMID:28788211

Proton conducting sol-gel sulfonated membranes produced from 2-allylphenol, 3-glycidoxypropyl trimethoxysilane and tetraethyl orthosilicate

NASA Astrophysics Data System (ADS)

Mosa, J.; Durán, A.; Aparicio, M.

An important research area in proton exchange membrane fuel cells (PEMFC) is devoted to the development of low cost membranes able to work at temperatures higher than 100 °C. In this work, homogeneous, transparent and crack-free hybrid membranes have been synthesized using tetraethyl orthosilicate (TEOS), 3-glycidoxipropyl trimethoxysilane (GPTMS) and 2-allylphenol (AP) as precursors. The synthesis of proton conducting membranes was performed by a post-sulfonation method using trimethylsilyl chlorosulfonate as a mild sulfonating agent. The water retention properties provided by sulfonate and hydroxyl groups and the high porosity leads to relatively high proton conductivity (maximum values around 1.3 × 10 -3 S cm -1 at 140 °C and 100% RH) for membranes treated at 180 °C and sulfonated for 2 h.

Consequences of Optimal Bond Valence on Structural Rigidity and Improved Luminescence Properties in Sr xBa 2-xSiO 4:Eu 2+ Orthosilicate Phosphors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denault, Kristin A.; Brgoch, Jakoah; Gaultois, Michael W.

The orthosilicate phosphors Sr xBa 2–xSiO 4:Eu 2+ have now been known for over four decades and have found extensive recent use in solid-state white lighting. It is well-recognized in the literature and in practice that intermediate compositions in the solid-solutions between the orthosilicates Sr 2SiO 4 and Ba 2SiO 4 yield the best phosphor hosts when the thermal stability of luminescence is considered. We employ a combination of synchrotron X-ray diffraction, total scattering measurements, density functional theory calculations, and low-temperature heat capacity measurements, in conjunction with detailed temperature- and time-resolved studies of luminescence properties to understand the origins ofmore » the improved luminescence properties. We observe that in the intermediate compositions, the two cation sites in the crystal structure are optimally bonded as determined from bond valence sum calculations. Optimal bonding results in a more rigid lattice, as established by the intermediate compositions possessing the highest Debye temperature, which are determined experimentally from low-temperature heat capacity measurements. Greater rigidity in turn results in the highest luminescence efficiency for intermediate compositions at elevated temperatures.« less

OXIDATION-RESISTANT COATING ON ARTICLES OF YTTRIUM METAL

DOEpatents

Wilder, D.R.; Wirkus, C.D.

1963-11-01

A process for protecting yttrium metal from oxidation by applying thereto and firing thereon a liquid suspension of a fritted ground silicate or phosphate glass plus from 5 to 35% by weight of CeO/sub 2/ is presented. (AEC)

Biochemical investigation of yttrium(III) complex containing 1,10-phenanthroline: DNA binding and antibacterial activity.

PubMed

Khorasani-Motlagh, Mozhgan; Noroozifar, Meissam; Moodi, Asieh; Niroomand, Sona

2013-03-05

Characterization of the interaction between yttrium(III) complex containing 1,10-phenanthroline as ligand, [Y(phen)2Cl(OH2)3]Cl2⋅H2O, and DNA has been carried out by UV absorption, fluorescence spectra and viscosity measurements in order to investigate binding mode. The experimental results indicate that the yttrium(III) complex binds to DNA and absorption is decreasing in charge transfer band with the increase in amount of DNA. The binding constant (Kb) at different temperatures as well as thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°), were calculated according to relevant fluorescent data and Vant' Hoff equation. The results of interaction mechanism studies, suggested that groove binding plays a major role in the binding of the complex and DNA. The activity of yttrium(III) complex against some bacteria was tested and antimicrobial screening tests shown growth inhibitory activity in the presence of yttrium(III) complex. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of a Monte Carlo Simulation for APD-Based PET Detectors Using a Continuous Scintillating Crystal

NASA Astrophysics Data System (ADS)

Clowes, P.; Mccallum, S.; Welch, A.

2006-10-01

We are currently developing a multilayer avalanche photodiode (APD)-based detector for use in positron emission tomography (PET), which utilizes thin continuous crystals. In this paper, we developed a Monte Carlo-based simulation to aid in the design of such detectors. We measured the performance of a detector comprising a single thin continuous crystal (3.1 mm times 9.5 mm times 9.5 mm) of lutetium yttrium ortho-silicate (LYSO) and an APD array (4times4) elements; each element 1.6 mm2 and on a 2.3 mm pitch. We showed that a spatial resolution of better than 2.12 mm is achievable throughout the crystal provided that we adopt a Statistics Based Positioning (SBP) Algorithm. We then used Monte Carlo simulation to model the behavior of the detector. The accuracy of the Monte Carlo simulation was verified by comparing measured and simulated parent datasets (PDS) for the SBP algorithm. These datasets consisted of data for point sources at 49 positions uniformly distributed over the detector area. We also calculated the noise in the detector circuit and verified this value by measurement. The noise value was included in the simulation. We show that the performance of the simulation closely matches the measured performance. The simulations were extended to investigate the effect of different noise levels on positioning accuracy. This paper showed that if modest improvements could be made in the circuit noise then positioning accuracy would be greatly improved. In summary, we have developed a model that can be used to simulate the performance of a variety of APD-based continuous crystal PET detectors

Proton trapping in yttrium-doped barium zirconate

NASA Astrophysics Data System (ADS)

Yamazaki, Yoshihiro; Blanc, Frédéric; Okuyama, Yuji; Buannic, Lucienne; Lucio-Vega, Juan C.; Grey, Clare P.; Haile, Sossina M.

2013-07-01

The environmental benefits of fuel cells have been increasingly appreciated in recent years. Among candidate electrolytes for solid-oxide fuel cells, yttrium-doped barium zirconate has garnered attention because of its high proton conductivity, particularly in the intermediate-temperature region targeted for cost-effective solid-oxide fuel cell operation, and its excellent chemical stability. However, fundamental questions surrounding the defect chemistry and macroscopic proton transport mechanism of this material remain, especially in regard to the possible role of proton trapping. Here we show, through a combined thermogravimetric and a.c. impedance study, that macroscopic proton transport in yttrium-doped barium zirconate is limited by proton-dopant association (proton trapping). Protons must overcome the association energy, 29 kJ mol-1, as well as the general activation energy, 16 kJ mol-1, to achieve long-range transport. Proton nuclear magnetic resonance studies show the presence of two types of proton environment above room temperature, reflecting differences in proton-dopant configurations. This insight motivates efforts to identify suitable alternative dopants with reduced association energies as a route to higher conductivities.

Proton trapping in yttrium-doped barium zirconate.

PubMed

Yamazaki, Yoshihiro; Blanc, Frédéric; Okuyama, Yuji; Buannic, Lucienne; Lucio-Vega, Juan C; Grey, Clare P; Haile, Sossina M

2013-07-01

The environmental benefits of fuel cells have been increasingly appreciated in recent years. Among candidate electrolytes for solid-oxide fuel cells, yttrium-doped barium zirconate has garnered attention because of its high proton conductivity, particularly in the intermediate-temperature region targeted for cost-effective solid-oxide fuel cell operation, and its excellent chemical stability. However, fundamental questions surrounding the defect chemistry and macroscopic proton transport mechanism of this material remain, especially in regard to the possible role of proton trapping. Here we show, through a combined thermogravimetric and a.c. impedance study, that macroscopic proton transport in yttrium-doped barium zirconate is limited by proton-dopant association (proton trapping). Protons must overcome the association energy, 29 kJ mol(-1), as well as the general activation energy, 16 kJ mol(-1), to achieve long-range transport. Proton nuclear magnetic resonance studies show the presence of two types of proton environment above room temperature, reflecting differences in proton-dopant configurations. This insight motivates efforts to identify suitable alternative dopants with reduced association energies as a route to higher conductivities.

Use of LysoTracker to detect programmed cell death in embryos and differentiating embryonic stem cells.

PubMed

Fogel, Jennifer L; Thein, Thu Zan Tun; Mariani, Francesca V

2012-10-11

Programmed cell death (PCD) occurs in adults to maintain normal tissue homeostasis and during embryological development to shape tissues and organs(1,2,6,7). During development, toxic chemicals or genetic alterations can cause an increase in PCD or change PCD patterns resulting in developmental abnormalities and birth defects(3-5). To understand the etiology of these defects, the study of embryos can be complemented with in vitro assays that use differentiating embryonic stem (ES) cells. Apoptosis is a well-studied form of PCD that involves both intrinsic and extrinsic signaling to activate the caspase enzyme cascade. Characteristic cell changes include membrane blebbing, nuclear shrinking, and DNA fragmentation. Other forms of PCD do not involve caspase activation and may be the end-result of prolonged autophagy. Regardless of the PCD pathway, dying cells need to be removed. In adults, the immune cells perform this function, while in embryos, where the immune system has not yet developed, removal occurs by an alternative mechanism. This mechanism involves neighboring cells (called "non-professional phagocytes") taking on a phagocytic role-they recognize the 'eat me' signal on the surface of the dying cell and engulf it(8-10). After engulfment, the debris is brought to the lysosome for degradation. Thus regardless of PCD mechanism, an increase in lysosomal activity can be correlated with increased cell death. To study PCD, a simple assay to visualize lysosomes in thick tissues and multilayer differentiating cultures can be useful. LysoTracker dye is a highly soluble small molecule that is retained in acidic subcellular compartments such as the lysosome(11-13). The dye is taken up by diffusion and through the circulation. Since penetration is not a hindrance, visualization of PCD in thick tissues and multi-layer cultures is possible(12,13). In contrast, TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling) analysis(14), is limited to small samples

Influence of the concentration of CO2 and SO2 on the absorption of CO2 by a lithium orthosilicate-based absorbent.

PubMed

Pacciani, R; Torres, J; Solsona, P; Coe, C; Quinn, R; Hufton, J; Golden, T; Vega, L F

2011-08-15

A novel, high temperature solid absorbent based on lithium orthosilicate (Li(4)SiO(4)) has shown promise for postcombustion CO(2) capture. Previous studies utilizing a clean, synthetic flue gas have shown that the absorbent has a high CO(2) capacity, >25 wt %, along with high absorption rates, lower heat of absorption and lower regeneration temperature than other solids such as calcium oxide. The current effort was aimed at evaluating the Li(4)SiO(4) based absorbent in the presence of contaminants found in typical flue gas, specifically SO(2), by cyclic exposure to gas mixtures containing CO(2), H(2)O (up to 25 vol. %), and SO(2) (up to 0.95 vol. %). In the absence of SO(2), a stable CO(2) capacity of ∼ 25 wt % over 25 cycles at 550 °C was achieved. The presence of SO(2), even at concentrations as low as 0.002 vol. %, resulted in an irreversible reaction with the absorbent and a decrease in CO(2) capacity. Analysis of SO(2)-exposed samples revealed that the absorbent reacted chemically and irreversibly with SO(2) at 550 °C forming Li(2)SO(4). Thus, industrial application would require desulfurization of flue gas prior to contacting the absorbent. Reactivity with SO(2) is not unique to the lithium orthosilicate material, so similar steps would be required for other absorbents that chemically react with SO(2).

Globotriaosylsphingosine (lyso-Gb3) might not be a reliable marker for monitoring the long-term therapeutic outcomes of enzyme replacement therapy for late-onset Fabry patients with the Chinese hotspot mutation (IVS4+919G>A)

PubMed Central

2014-01-01

Background In Taiwan, DNA-based newborn screening showed a surprisingly high incidence (1/875 in males and 1/399 in females) of a cardiac Fabry mutation (IVS4 + 919G > A). However, the natural course, long-term treatment outcomes and suitable biomarkers for monitoring the therapeutic outcomes of these patients are largely unknown. Methods Fabry disease (FD) patients who had received enzyme replacement therapy (ERT) for more than 1 year were enrolled in this study from December 2008 to April 2013. Periodic echocardiography and serum globotriaosylsphingosine (lyso-Gb3) analysis were carried out. Before and after ERT, left ventricular mass index (LVMI) and serum lyso-Gb3 level were compared and the correlation between the change of LVMI and the change of serum lyso-Gb3 were also analyzed. Results Thirty-six patients, in four patient groups, were enrolled: (1) 16 males with IVS4 + 919G > A mutation; (2) 7 females with IVS4 + 919G > A mutation; (3) 2 males with classical mutations; and (4) 11 females with classical mutations. The follow-up period was 13–46 months. There were significant LVMI reductions after ERT in all four groups after excluding confounding factors. However, interestingly, serum lyso-Gb3 decreased significantly in the early period after ERT in all groups, but increased gradually after an average of 11.1 months after ERT in late-onset male and female Fabry groups, even when their LVMI still decreased or remained stable. Furthermore, there was no correlation between the change of serum lyso-Gb3 and the change of LVMI in both classical and IVS4 + 919G > A FD patients. Conclusion Although lyso-Gb3 has a high diagnostic sensitivity in late-onset Fabry patients and has a good response to ERT during the early stages, it might not be a reliable marker for monitoring the long-term therapeutic outcomes of ERT for late-onset Fabry patients with the Chinese hotspot mutation (IVS4 + 919G > A). PMID:25047006

The effect of yttrium and thorium on the oxidation behavior of Ni-Cr-Al alloys

NASA Technical Reports Server (NTRS)

Kumar, A.; Nasrallah, M.; Douglass, D. L.

1974-01-01

The effect of quaternary additions of 0.5% Y, 0.5 and 1.0% Th to a base alloy of Ni-10CR-5Al on the oxidation behavior and mechanism was studied during oxidation in air over the range of 1000 to 1200 C. The presence of yttrium decreased the oxidation kinetics slightly, whereas, the addition of thorium caused a slight increase. Oxide scale adherence was markedly improved by the addition of the quaternary elements. Although a number of oxides formed on yttrium containing alloys, quantitative X-ray diffraction clearly showed that the rate-controlling step was the diffusion of aluminum through short circuit paths in a thin layer of alumina that formed parabolically with time. Although the scale adherence of the yttrium containing alloy was considerably better than the base alloys, spalling did occur that was attributed to the formation of the voluminous YAG particles which grew in a mushroom-like manner, lifting the protective scale off the subrate locally. The YAG particles formed primarily at grain boundaries in the substrate in which the yttrium originally existed as YNi9.

The reactive element effect of yttrium and yttrium silicon on high temperature oxidation of NiCrAl coating

NASA Astrophysics Data System (ADS)

Ramandhany, S.; Sugiarti, E.; Desiati, R. D.; Martides, E.; Junianto, E.; Prawara, B.; Sukarto, A.; Tjahjono, A.

2018-03-01

The microstructure formed on the bond coat affects the oxidation resistance, particularly the formation of a protective oxide layer. The adhesion of bond coat and TGO increased significantly by addition of reactive element. In the present work, the effect of yttrium and yttrium silicon as reactive element (RE) on NiCrAl coating was investigated. The NiCrAl (without RE) and NiCrAlX (X:Y or YSi) bond coating were deposited on Hastelloy C-276 substrate by High Velocity Oxygen Fuel (HVOF) method. Isothermal oxidation was carried out at 1000 °C for 100 hours. The results showed that the addition of RE could prevent the breakaway oxidation. Therefore, the coating with reactive element were more protective against high temperature oxidation. Furthermore, the oxidation rate of NiCrAlY coating was lower than NiCrAlYSi coating with the total mass change was ±2.394 mg/cm2 after 100 hours of oxidation. The thickness of oxide scale was approximately 1.18 μm consisting of duplex oxide scale of spinel NiCr2O4 in outer scale and protective α-Al2O3 in inner scale.

A Study on Factors Affecting the Degradation of Magnesium and a Magnesium-Yttrium Alloy for Biomedical Applications

PubMed Central

Johnson, Ian; Liu, Huinan

2013-01-01

Controlling degradation of magnesium or its alloys in physiological saline solutions is essential for their potential applications in clinically viable implants. Rapid degradation of magnesium-based materials reduces the mechanical properties of implants prematurely and severely increases alkalinity of the local environment. Therefore, the objective of this study is to investigate the effects of three interactive factors on magnesium degradation, specifically, the addition of yttrium to form a magnesium-yttrium alloy versus pure magnesium, the metallic versus oxide surfaces, and the presence versus absence of physiological salt ions in the immersion solution. In the immersion solution of phosphate buffered saline (PBS), the magnesium-yttrium alloy with metallic surface degraded the slowest, followed by pure magnesium with metallic or oxide surfaces, and the magnesium-yttrium alloy with oxide surface degraded the fastest. However, in deionized (DI) water, the degradation rate showed a different trend. Specifically, pure magnesium with metallic or oxide surfaces degraded the slowest, followed by the magnesium-yttrium alloy with oxide surface, and the magnesium-yttrium alloy with metallic surface degraded the fastest. Interestingly, only magnesium-yttrium alloy with metallic surface degraded slower in PBS than in DI water, while all the other samples degraded faster in PBS than in DI water. Clearly, the results showed that the alloy composition, presence or absence of surface oxide layer, and presence or absence of physiological salt ions in the immersion solution all influenced the degradation rate and mode. Moreover, these three factors showed statistically significant interactions. This study revealed the complex interrelationships among these factors and their respective contributions to degradation for the first time. The results of this study not only improved our understanding of magnesium degradation in physiological environment, but also presented the key

Yttrium-90 microspheres for the treatment of hepatocellular carcinoma: A review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salem, Riad; Hunter, Russell D.

2006-10-01

To present a critical review of yttrium-90 (TheraSphere) for the treatment of hepatocellular carcinoma (HCC). Medical literature databases (Medline, Cochrane Library, and CANCERLIT) were searched for available literature concerning the treatment of HCC with TheraSphere. These publications were reviewed for scientific and clinical validity. Studies pertaining to the use of yttrium-90 for HCC date back to the 1960s. The results from the early animal safety studies established a radiation exposure range of 50-100 Gy to be used in human studies. Phase I dose escalation studies followed, which were instrumental in delineating radiation dosimetry and safety parameters in humans. These earlymore » studies emphasized the importance of differential arteriolar density between hypervascular HCC and surrounding liver parenchyma. Current trends in research have focused on advancing techniques to safely implement this technology as an alternative to traditional methods of treating unresectable HCC, such as external beam radiotherapy, conformal beam radiotherapy, ethanol ablation, trans-arterial chemoembolization, and radiofrequency ablation. Yttrium-90 (TheraSphere) is an outpatient treatment option for HCC. Current and future research should focus on implementing multicenter phase II and III trials comparing TheraSphere with other therapies for HCC.« less

Reinforced Carbon Carbon (RCC) oxidation resistant material samples - Baseline coated, and baseline coated with tetraethyl orthosilicate (TEOS) impregnation

NASA Technical Reports Server (NTRS)

Gantz, E. E.

1977-01-01

Reinforced carbon-carbon material specimens were machined from 19 and 33 ply flat panels which were fabricated and processed in accordance with the specifications and procedures accepted for the fabrication and processing of the leading edge structural subsystem (LESS) elements for the space shuttle orbiter. The specimens were then baseline coated and tetraethyl orthosilicate impregnated, as applicable, in accordance with the procedures and requirements of the appropriate LESS production specifications. Three heater bars were ATJ graphite silicon carbide coated with the Vought 'pack cementation' coating process, and three were stackpole grade 2020 graphite silicon carbide coated with the chemical vapor deposition process utilized by Vought in coating the LESS shell development program entry heater elements. Nondestructive test results are reported.

Treatment of unresectable intrahepatic cholangiocarcinoma with yttrium-90 radioembolization: a systematic review and pooled analysis.

PubMed

Al-Adra, D P; Gill, R S; Axford, S J; Shi, X; Kneteman, N; Liau, S-S

2015-01-01

Radioembolization with yttrium-90 microspheres offers an alternative treatment option for patients with unresectable intrahepatic cholangiocarcinoma (ICC). However, the rarity and heterogeneity of ICC makes it difficult to draw firm conclusions about treatment efficacy. Therefore, the goal of the current study is to systematically review the existing literature surrounding treatment of unresectable ICCs with yttrium-90 microspheres and provide a comprehensive review of the current experience and clinical outcome of this treatment modality. We performed a comprehensive search of electronic databases for ICC treatment and identified 12 studies with relevant data regarding radioembolization therapy with yttrium-90 microspheres. Based on pooled analysis, the overall weighted median survival was 15.5 months. Tumour response based on radiological studies demonstrated a partial response in 28% and stable disease in 54% of patients at three months. Seven patients were able to be downstaged to surgical resection. The complication profile of radioembolization is similar to that of other intra-arterial treatment modalities. Overall survival of patients with ICC after treatment with yttrium-90 microspheres is higher than historical survival rates and shows similar survival to those patients treated with systemic chemotherapy and/or trans-arterial chemoembolization therapy. Therefore, the use of yttrium-90 microspheres should be considered in the list of available treatment options for ICC. However, future randomized trials comparing systemic chemotherapy, TACE and local radiation will be required to identify the optimal treatment modality for unresectable ICC. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Optimization of a large-area detector-block based on SiPM and pixelated LYSO crystal arrays.

PubMed

Calva-Coraza, E; Alva-Sánchez, H; Murrieta-Rodríguez, T; Martínez-Dávalos, A; Rodríguez-Villafuerte, M

2017-10-01

We present the performance evaluation of a large-area detector module based on the ArrayC-60035-64P, an 8×8 array of tileable, 7.2mm pitch, silicon photomultipliers (SiPM) by SensL, covering a total area of 57.4mm×57.4mm. We characterized the ArrayC-60035-64P, operating at room temperature, using LYSO pixelated crystal arrays of different pitch sizes (1.075, 1.430, 1.683, 2.080 and 2.280mm) to determine the resolvable crystal size. After an optimization process, a 7mm thick coupling light guide was used for all crystal pitches. To identify the interaction position a 16-channel (8 columns, 8 rows) symmetric charge division (SCD) readout board together with a center-of-gravity algorithm was used. Based on this, we assembled the detector modules using a 40×40 LYSO, 1.43mm pitch array, covering the total detector area. Calibration was performed using a 137 Cs source resulting in excellent crystal maps with minor geometric distortion, a mean 4.1 peak-to-valley ratio and 9.6% mean energy resolution for 662keV photons in the central region. The resolvability index was calculated in the x and y directions with values under 0.42 in all cases. We show that these large area SiPM arrays, combined with a 16-channel SCD readout board, can offer high spatial resolution, without processing a big number of signals, attaining excellent energy resolution and detector uniformity. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Photonuclear production of yttrium-88 - A high energy gamma emitter for hydrocarbon extraction applications.

PubMed

Dale, Daniel S; Starovoitova, Valeriia N; Forest, Tony A; Oliphant, Emily

2018-05-05

The use of fracing has risen over the past decade and revolutionized energy production in the US. However, there is still an impetus for further optimization of the extraction of oil and natural gas from vast shale reservoirs. In this work, we discuss photonuclear production of yttrium-88 as a promising radiotracer for fracing operations. Single neutron knock-out from natural monoisotopic yttrium-89 is an inexpensive process resulting in high activity of 88 Y with minimal impurities. MCNPX simulations were performed to estimate the 88 Y yield. Irradiations of natural yttrium using a 32 MeV electron linac equipped with a tungsten bremsstrahlung converter were done to benchmark the simulations. Activities of 88 Y, 87g Y, and 87m Y were measured and found to be in good agreement with the predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Quantitative description of yttrium aluminate ceramic composition by means of Er+3 microluminescence spectrum

NASA Astrophysics Data System (ADS)

Videla, F. A.; Tejerina, M. R.; Moreira-Osorio, L.; Conconi, M. S.; Orzi, D. J. O.; Flores, T.; Ponce, L. V.; Bilmes, G. M.; Torchia, G. A.

2018-05-01

The composition of erbium-doped yttrium aluminate ceramics was analyzed by means of confocal luminescence spectroscopy, EDX, and X-ray diffraction. A well-defined linear correlation was found between a proposed estimator computed from the luminescence spectrum and the proportion of ceramic phases coexisting in different samples. This result shows the feasibility of using erbium luminescence spectroscopy to perform a quantitative determination of different phases of yttrium aluminates within a micrometric region in nanograined ceramics.

Phonon anharmonicity of monoclinic zirconia and yttrium-stabilized zirconia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Chen W.; Smith, Hillary L.; Lan, Tian

2015-04-13

Inelastic neutron scattering measurements on monoclinic zirconia (ZrO 2) and 8 mol% yttrium-stabilized zirconia were performed at temperatures from 300 to 1373 ωK. We reported temperature-dependent phonon densities of states (DOS) and Raman spectra obtained at elevated temperatures. First-principles lattice dynamics calculations with density functional theory gave total and partial phonon DOS curves and mode Grüneisen parameters. These mode Grüneisen parameters were used to predict the experimental temperature dependence of the phonon DOS with partial success. However, substantial anharmonicity was found at elevated temperatures, especially for phonon modes dominated by the motions of oxygen atoms. Yttrium-stabilized zirconia (YSZ) was somewhatmore » more anharmonic and had a broader phonon spectrum at low temperatures, owing in part to defects in its structure. YSZ also has a larger vibrational entropy than monoclinic zirconia.« less

Method of forming a relatively stable slip of silicon metal particles and yttrium containing particles

DOEpatents

Dickie, Ray A.; Mangels, John A.

1984-01-01

The method concerns forming a relatively stable slip of silicon metal particles and yttrium containing particles. In one embodiment, a casting slip of silicon metal particles is formed in water. Particles of a yttrium containing sintering aid are added to the casting slip. The yttrium containing sintering aid is a compound which has at least some solubility in water to form Y.sup.+3 ions which have a high potential for totally flocculating the silicon metal particles into a semiporous solid. A small amount of a fluoride salt is added to the casting slip which contains the yttrium containing sintering aid. The fluoride salt is one which will produce fluoride anions when dissolved in water. The small amount of the fluoride anions produced are effective to suppress the flocculation of the silicon metal particles by the Y.sup.+3 ions so that all particles remain in suspension in the casting slip and the casting slip has both an increased shelf life and can be used to cast articles having a relatively thick cross-section. The pH of the casting slip is maintained in a range from 7.5 to 9. Preferably, the fluoride salt used is one which is based on a monovalent cation such as sodium or ammonia. The steps of adding the yttrium containing sintering aid and the fluoride salt may be interchanged if desired, and the salt may be added to a solution containing the sintering aid prior to addition of the silicon metal particles.

Characterization of yttrium-rich precipitates in a titanium alloy weld

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolli, R. Prakash, E-mail: pkolli@umd.edu

The yttrium-rich (Y-rich) precipitates that form in the fusion zone (FZ) of a Ti–5Al–1Sn–1Zr–1V–0.8Mo (wt.%) alloy, or Ti-5111, gas-tungsten arc welds (GTAW) were characterized. The filler metal was modified by a small concentration of Y in order to refine the microstructure and thus improve the FZ ductility. A high number density of nanoscale Y-rich precipitates were characterized in the weld FZ by atom probe tomography (APT) and scanning transmission electron microscopy (STEM). - Highlights: •A high number density of nanoscale precipitates were observed in the FZ matrix. •The nanoscale precipitates are enriched in yttrium. •Oxygen and sulfur are also presentmore » in the Y-rich precipitates and their interfaces.« less

Effects of yttrium, aluminum, and chromium concentrations in bond coatings on the performance of zirconia-yttria thermal barriers

NASA Technical Reports Server (NTRS)

Stecura, S.

1979-01-01

A cyclic furnace study was conducted between 990 - 280 C and 1095 - 280 C to evaluate the effects of yttrium, chromium, and aluminum concentrations in nickel base alloy bond coatings and also the effect of the bond coating thickness on the performance of yttria-stabilized zirconia thermal barrier coatings. The presence and the concentration of yttrium is very critical. Without yttrium, rapid oxidation of Ni-Al, Ni-Cr, and Ni-Cr-Al bond coatings causes zirconia thermal barrier coatings to fail very rapidly. Concentrations of chrominum and aluminum in Ni-Cr-Al-Y bond coating have a very significant effect on the thermal barrier coating life. This effect, however, is not as great as that due to yttrium. Furthermore, the thickness and the thickness uniformity also have a very significant effect on the life of the thermal barrier system.

Spectral hole lifetimes and spin population relaxation dynamics in neodymium-doped yttrium orthosilicate

NASA Astrophysics Data System (ADS)

Cruzeiro, E. Zambrini; Tiranov, A.; Usmani, I.; Laplane, C.; Lavoie, J.; Ferrier, A.; Goldner, P.; Gisin, N.; Afzelius, M.

2017-05-01

We present a detailed study of the lifetime of optical spectral holes due to population storage in Zeeman sublevels of Nd3 +:Y2SiO5 . The lifetime is measured as a function of magnetic field strength and orientation, temperature, and Nd3 + doping concentration. At the lowest temperature of 3 K we find a general trend where the lifetime is short at low field strengths, then increases to a maximum lifetime at a few hundred mT, and then finally decays rapidly for high field strengths. This behavior can be modeled with a relaxation rate dominated by Nd3 +-Nd3 + cross relaxation at low fields and spin lattice relaxation at high magnetic fields. The maximum lifetime depends strongly on both the field strength and orientation, due to the competition between these processes and their different angular dependencies. The cross relaxation limits the maximum lifetime for concentrations as low as 30 ppm of Nd3 + ions. By decreasing the concentration to less than 1 ppm we could completely eliminate the cross relaxation, reaching a lifetime of 3.8 s at 3 K. At higher temperatures the spectral hole lifetime is limited by the magnetic-field-independent Raman and Orbach processes. In addition we show that the cross relaxation rate can be strongly reduced by creating spectrally large holes of the order of the optical inhomogeneous broadening. Our results are important for the development and design of new rare-earth-ion doped crystals for quantum information processing and narrow-band spectral filtering for biological tissue imaging.

Intraprocedural yttrium-90 positron emission tomography/CT for treatment optimization of yttrium-90 radioembolization.

PubMed

Bourgeois, Austin C; Chang, Ted T; Bradley, Yong C; Acuff, Shelley N; Pasciak, Alexander S

2014-02-01

Radioembolization with yttrium-90 ((90)Y) microspheres relies on delivery of appropriate treatment activity to ensure patient safety and optimize treatment efficacy. We report a case in which (90)Y positron emission tomography (PET)/computed tomography (CT) was performed to optimize treatment planning during a same-day, three-part treatment session. This treatment consisted of (i) an initial (90)Y infusion with a dosage determined using an empiric treatment planning model, (ii) quantitative (90)Y PET/CT imaging, and (iii) a secondary infusion with treatment planning based on quantitative imaging data with the goal of delivering a specific total tumor absorbed dose. © 2014 SIR Published by SIR All rights reserved.

Live Imaging of LysoTracker-Labelled Phagolysosomes Tracks Diurnal Phagocytosis of Photoreceptor Outer Segment Fragments in Rat RPE Tissue Ex Vivo.

PubMed

Mao, Yingyu; Finnemann, Silvia C

2016-01-01

Renewal of rod photoreceptor outer segments in the mammalian eye involves synchronized diurnal shedding after light onset of spent distal outer segment fragments (POS) linked to swift clearance of shed POS from the subretinal space by the adjacent retinal pigment epithelium (RPE). Engulfed POS phagosomes in RPE cells mature to acidified phagolysosomes, which accomplish enzymatic degradation of POS macromolecules. Here, we used an acidophilic fluorophore LysoTracker to label acidic organelles in freshly dissected, live rat RPE tissue flat mounts. We observed that all RPE cells imaged contained numerous acidified POS phagolysosomes whose abundance per cell was dramatically increased 2 h after light onset as compared to either 1 h before or 4 h after light onset. Lack of organelles of similar diameter (of 1-2 μm) in phagocytosis-defective mutant RCS rat RPE confirmed that LysoTracker live imaging detected POS phagolysosomes. Lack of increase in lysosomal membrane protein LAMP-1 in RPE/choroid during the diurnal phagocytic burst suggests that formation of POS phagolysosomes in RPE in situ may not involve extra lysosome membrane biogenesis. Taken together, we report a new imaging approach that directly detects POS phagosome acidification and allows rapid tracking and quantification of POS phagocytosis by live RPE -tissue ex situ.

MCrAlY bond coat with enhanced Yttrium layer

DOEpatents

Jablonski, Paul D; Hawk, Jeffrey A

2015-04-21

One or more embodiments relates to an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y--Al oxides, providing advantage in the maintainability of the Yttrium reservoir within the MCrAlY bulk. The MCrAlY bond coat may be fabricated through application of a Y.sub.2O.sub.3 paste to an MCrAlY material, followed by heating in a non-oxidizing environment.

Abscopal Effects and Yttrium-90 Radioembolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghodadra, Anish; Bhatt, Sumantha; Camacho, Juan C.

2016-07-15

We present the case of an 80-year-old male with squamous cell carcinoma with bilobar hepatic metastases who underwent targeted Yttrium-90 radioembolization of the right hepatic lobe lesion. Subsequently, there was complete regression of the nontargeted, left hepatic lobe lesion. This may represent the first ever reported abscopal effect in radioembolization. The abscopal effect refers to the phenomenon of tumor response in nontargeted sites after targeted radiotherapy. In this article, we briefly review the immune-mediated mechanisms responsible for the abscopal effect.

Isotope shifts from collinear laser spectroscopy of doubly charged yttrium isotopes

NASA Astrophysics Data System (ADS)

Vormawah, L. J.; Vilén, M.; Beerwerth, R.; Campbell, P.; Cheal, B.; Dicker, A.; Eronen, T.; Fritzsche, S.; Geldhof, S.; Jokinen, A.; Kelly, S.; Moore, I. D.; Reponen, M.; Rinta-Antila, S.; Stock, S. O.; Voss, A.

2018-04-01

Collinear laser spectroscopy has been performed on doubly charged ions of radioactive yttrium in order to study the isotope shifts of the 294.6-nm 5 s 1/2 2S →5 p 1/2 2P line. The potential of such an alkali-metal-like transition to improve the reliability of atomic-field-shift and mass-shift factor calculations, and hence the extraction of nuclear mean-square radii, is discussed. Production of yttrium ion beams for such studies is available at the IGISOL IV Accelerator Laboratory, Jyväskylä, Finland. This newly recommissioned facility is described here in relation to the on-line study of accelerator-produced short-lived isotopes using collinear laser spectroscopy and application of the technique to doubly charged ions.

The influence of implanted yttrium on the cyclic oxidation behaviour of 304 stainless steel

NASA Astrophysics Data System (ADS)

Riffard, F.; Buscail, H.; Caudron, E.; Cueff, R.; Issartel, C.; Perrier, S.

2006-03-01

High-temperature alloys are frequently used in power plants, gasification systems, petrochemical industry, combustion processes and in aerospace applications. Depending on the application, materials are subjected to corrosive atmospheres and thermal cycling. In the present work, thermal cycling was carried out in order to study the influence of implanted yttrium on the oxide scale adherence on 304 steel specimens oxidised in air at 1273 K. In situ X-ray diffraction indicates that the oxides formed at 1273 K are different on blank specimens compared to implanted specimens. Glancing angle XRD allows to analyse the oxide scale composition after cooling to room temperature. Experimental results show that yttrium implantation at a nominal dose of 10 17 ions cm -2 does not improve significantly the cyclic oxidation behaviour of the austenitic AISI 304 steel. However, it appears that yttrium implantation remarkably enhance the oxidation resistance during isothermal oxidation. It reduces the transient oxidation stage and the parabolic oxidation rate constant by one order of magnitude.

Evaluating the improvement of corrosion residual strength by adding 1.0 wt.% yttrium into an AZ91D magnesium alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Qiang; Liu Yaohui, E-mail: liuyaohui2005@yahoo.com; Fang Shijie

2010-06-15

The influence of yttrium on the corrosion residual strength of an AZ91D magnesium alloy was investigated detailedly. Scanning electron microscope was employed to analyze the microstructure and the fractography of the studied alloys. The microstructure of AZ91D magnesium alloy is remarkably refined due to the addition of yttrium. The electrochemical potentiodynamic polarization curve of the studied alloy was performed with a CHI 660b electrochemical station in the three-electrode system. The result reveals that yttrium significantly promotes the overall corrosion resistance of AZ91D magnesium alloy by suppressing the cathodic reaction in corrosion process. However, the nucleation and propagation of corrosion pitsmore » on the surface of the 1.0 wt.% Y modified AZ91D magnesium alloy indicate that pitting corrosion still emerges after the addition of yttrium. Furthermore, stress concentration caused by corrosion pits should be responsible for the drop of corrosion residual strength although the addition of yttrium remarkably weakens the effect of stress concentration at the tip of corrosion pits in loading process.« less

Measurement of LYSO Intrinsic Light Yield Using Electron Excitation

NASA Astrophysics Data System (ADS)

Turtos, Rosana Martinez; Gundacker, Stefan; Pizzichemi, Marco; Ghezzi, Alessio; Pauwels, Kristof; Auffray, Etiennette; Lecoq, Paul; Paganoni, Marco

2016-04-01

The determination of the intrinsic light yield (LYint) of scintillating crystals, i.e. number of optical photons created per amount of energy deposited, constitutes a key factor in order to characterize and optimize their energy and time resolution. However, until now measurements of this quantity are affected by large uncertainties and often rely on corrections for bulk absorption and surface/edge state. The novel idea presented in this contribution is based on the confinement of the scintillation emission in the central upper part of a 10 mm cubic crystal using a 1.5 MeV electron beam with diameter of 1 mm. A black non-reflective pinhole aligned with the excitation point is used to fix the light extraction solid angle (narrower than total reflection angle), which then sets a light cone travel path through the crystal. The final number of photoelectrons detected using a Hamamatsu R2059 photomultiplier tube (PMT) was corrected for the extraction solid angle, the Fresnel reflection coefficient and quantum efficiency (QE) of the PMT. The total number of optical photons produced per energy deposited was found to be 40000 ph/MeV ± 9% (syst) ±3% (stat) for LYSO. Simulations using Geant4 were successfully compared to light output measurements of 2 × 2 mm2 section crystals with lengths of 5-30 mm, in order to validate the light transport model and set a limit on Light Transfer Efficiency estimations.

Hydrothermal synthesis, crystal structures and photoluminescence properties of mixed europium-yttrium organic frameworks

NASA Astrophysics Data System (ADS)

Han, Yinfeng; Fu, Lianshe; Mafra, Luís; Shi, Fa-Nian

2012-02-01

Three mixed europium-yttrium organic frameworks: Eu2-xYx(Mel)(H2O)6 (Mel=mellitic acid or benzene-1,2,3,4,5,6-hexacarboxylic acid, x=0.38 1, 0.74 2, and 0.86 3) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu3+ lifetime becomes longer in these MOFs than those of the Eu analog.

Intrinsic spatial resolution evaluation of the X'tal cube PET detector based on a 3D crystal block segmented by laser processing.

PubMed

Yoshida, Eiji; Tashima, Hideaki; Inadama, Naoko; Nishikido, Fumihiko; Moriya, Takahiro; Omura, Tomohide; Watanabe, Mitsuo; Murayama, Hideo; Yamaya, Taiga

2013-01-01

The X'tal cube is a depth-of-interaction (DOI)-PET detector which is aimed at obtaining isotropic resolution by effective readout of scintillation photons from the six sides of a crystal block. The X'tal cube is composed of the 3D crystal block with isotropic resolution and arrays of multi-pixel photon counters (MPPCs). In this study, to fabricate the 3D crystal block efficiently and precisely, we applied a sub-surface laser engraving (SSLE) technique to a monolithic crystal block instead of gluing segmented small crystals. The SSLE technique provided micro-crack walls which carve a groove into a monolithic scintillator block. Using the fabricated X'tal cube, we evaluated its intrinsic spatial resolution to show a proof of concept of isotropic resolution. The 3D grids of 2 mm pitch were fabricated into an 18 × 18 × 18 mm(3) monolithic lutetium yttrium orthosilicate (LYSO) crystal by the SSLE technique. 4 × 4 MPPCs were optically coupled to each surface of the crystal block. The X'tal cube was uniformly irradiated by (22)Na gamma rays, and all of the 3D grids on the 3D position histogram were separated clearly by an Anger-type calculation from the 96-channel MPPC signals. Response functions of the X'tal cube were measured by scanning with a (22)Na point source. The gamma-ray beam with a 1.0 mm slit was scanned in 0.25 mm steps by positioning of the X'tal cube at vertical and 45° incident angles. The average FWHM resolution at both incident angles was 2.1 mm. Therefore, we confirmed the isotropic spatial resolution performance of the X'tal cube.

Fabrication of dense yttrium oxyfluoride ceramics by hot pressing and their mechanical, thermal, and electrical properties

NASA Astrophysics Data System (ADS)

Tahara, Ryuki; Tsunoura, Toru; Yoshida, Katsumi; Yano, Toyohiko; Kishi, Yukio

2018-06-01

Excellent corrosion-resistant materials have been strongly required to reduce particle contamination during the plasma process in semiconductor production. Yttrium oxyfluoride can be a candidate as highly corrosion-resistant material. In this study, three types of dense yttrium oxyfluoride ceramics with different oxygen contents, namely, YOF, Y5O4F7 and Y5O4F7 + YF3, were fabricated by hot pressing, and their mechanical, thermal, and electrical properties were evaluated. Y5O4F7 ceramics showed an excellent thermal stability up to 800 °C, a low loss factor, and volume resistivity comparable to conventional plasma-resistant oxides, such as Y2O3. From these results, yttrium oxyfluoride ceramics are strongly suggested to be used as electrostatic chucks in semiconductor production.

Hydrothermal synthesis, crystal structures and photoluminescence properties of mixed europium-yttrium organic frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han Yinfeng; Department of Chemistry and Environmental Science, Taishan University, Taian 271021; Fu Lianshe

Three mixed europium-yttrium organic frameworks: Eu{sub 2-x}Y{sub x}(Mel)(H{sub 2}O){sub 6} (Mel=mellitic acid or benzene-1,2,3,4,5,6-hexacarboxylic acid, x=0.38 1, 0.74 2, and 0.86 3) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu{sup 3+} lifetime becomes longer in these MOFs than those of the Eu analog. - Graphical abstract: Three mixed europium and yttrium organic frameworks: Eu{sub 2-x}Y{sub x}(Mel)(H{sub 2}O){sub 6} (Mel=mellitic acid) have been synthesized and characterized.more » All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu{sup 3+} lifetime becomes longer in these MOFs than those of the Eu analog. Highlights: Black-Right-Pointing-Pointer Three (4, 8)-flu topological mixed Eu and Y MOFs were synthesized under mild conditions. Black-Right-Pointing-Pointer Metal ratios were refined by the single crystal data consistent with the EDS analysis. Black-Right-Pointing-Pointer Mixed Eu and Y MOFs show longer lifetime and higher quantum efficiency than the Eu analog. Black-Right-Pointing-Pointer Adding inert lanthanide into luminescent MOFs enlarges the field of luminescent MOFs.« less

Dense nanocrystalline yttrium iron garnet films formed at room temperature by aerosol deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Scooter D., E-mail: scooter.johnson@nrl.navy.mil; Glaser, Evan R.; Cheng, Shu-Fan

Highlights: • We deposit yttrium iron garnet films at room temperature using aerosol deposition. • Films are 96% of theoretical density for yttrium iron garnet. • We report magnetic and structural properties post-deposition and post-annealing. • Low-temperature annealing decreases the FMR linewidth. • We discuss features of the FMR spectra at each anneal temperature. - Abstract: We have employed aerosol deposition to form polycrystalline yttrium iron garnet (YIG) films on sapphire at room temperature that are 90–96% dense. We characterize the structural and dynamic magnetic properties of the dense films using scanning electron microscopy, X-ray diffraction, and ferromagnetic resonance techniques.more » We find that the as-deposited films are pure single-phase YIG formed of compact polycrystallites ∼20 nm in size. The ferromagnetic resonance mode occurs at 2829 G with a linewidth of 308 G. We perform a series of successive anneals up to 1000 °C on a film to explore heat treatment on the ferromagnetic resonance linewidth. We find the narrowest linewidth of 98 G occurs after a 750 °C anneal.« less

Demonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells.

PubMed

Bae, Kiho; Jang, Dong Young; Choi, Hyung Jong; Kim, Donghwan; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won; Shim, Joon Hyung

2017-02-23

In reducing the high operating temperatures (≥800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (≤600 °C). Among many protonic ceramics, yttrium-doped barium zirconate has attracted attention due to its excellent chemical stability, which is the main issue in protonic-ceramic fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance. Here we fabricate a protonic-ceramic fuel cell using a thin-film-deposited yttrium-doped barium zirconate electrolyte with no impeding grain boundaries owing to the columnar structure tightly integrated with nanogranular cathode and nanoporous anode supports, which to the best of our knowledge exhibits a record high-power output of up to an order of magnitude higher than those of other reported barium zirconate-based fuel cells.

SPIO-labeled Yttrium Microspheres for MR Imaging Quantification of Transcatheter Intrahepatic Delivery in a Rodent Model

PubMed Central

Li, Weiguo; Zhang, Zhuoli; Gordon, Andrew C.; Chen, Jeane; Nicolai, Jodi; Lewandowski, Robert J.; Omary, Reed A.

2016-01-01

Purpose To investigate the qualitative and quantitative impacts of labeling yttrium microspheres with increasing amounts of superparamagnetic iron oxide (SPIO) material for magnetic resonance (MR) imaging in phantom and rodent models. Materials and Methods Animal model studies were approved by the institutional Animal Care and Use Committee. The r2* relaxivity for each of four microsphere SPIO compositions was determined from 32 phantoms constructed with agarose gel and in eight concentrations from each of the four compositions. Intrahepatic transcatheter infusion procedures were performed in rats by using each of the four compositions before MR imaging to visualize distributions within the liver. For quantitative studies, doses of 5, 10, 15, or 20 mg 2% SPIO-labeled yttrium microspheres were infused into 24 rats (six rats per group). MR imaging R2* measurements were used to quantify the dose delivered to each liver. Pearson correlation, analysis of variance, and intraclass correlation analyses were performed to compare MR imaging measurements in phantoms and animal models. Results Increased r2* relaxivity was observed with incremental increases of SPIO microsphere content. R2* measurements of the 2% SPIO–labeled yttrium microsphere concentration were well correlated with known phantom concentrations (R2 = 1.00, P < .001) over a broader linear range than observed for the other three compositions. Microspheres were heterogeneously distributed within each liver; increasing microsphere SPIO content produced marked signal voids. R2*-based measurements of 2% SPIO–labeled yttrium microsphere delivery were well correlated with infused dose (intraclass correlation coefficient, 0.98; P < .001). Conclusion MR imaging R2* measurements of yttrium microspheres labeled with 2% SPIO can quantitatively depict in vivo intrahepatic biodistribution in a rat model. © RSNA, 2015 Online supplemental material is available for this article. PMID:26313619

Effect of yttrium on martensite-austenite phase transformation temperatures and high temperature oxidation kinetics of Ti-Ni-Hf high-temperature shape memory alloys

NASA Astrophysics Data System (ADS)

Kim, Jeoung Han; Kim, Kyong Min; Yeom, Jong Taek; Young, Sung

2016-03-01

The effect of yttrium (< 5.5 at%) on the martensite-austenite phase transformation temperatures, microstructural evolution, and hot workability of Ti-Ni-Hf high-temperature shape memory alloys is investigated. For these purposes, differential scanning calorimetry, hot compression, and thermo-gravimetric tests are conducted. The phase transformation temperatures are not noticeably influenced by the addition of yttrium up to 4.5 at%. Furthermore, the hot workability is not significantly affected by the yttrium addition up to 1.0 at%. However, when the amount of yttrium addition exceeds 1.0 at%, the hot workability deteriorates significantly. In contrast, remarkable improvement in the high temperature oxidation resistance due to the yttrium addition is demonstrated. The total thickness of the oxide layers is substantially thinner in the Y-added specimen. In particular, the thickness of (Ti,Hf) oxide layer is reduced from 200 µm to 120 µm by the addition of 0.3 at% Y.

Optimization Recovery of Yttrium Oxide in Precipitation, Extraction, and Stripping Process

NASA Astrophysics Data System (ADS)

Perwira, N. I.; Basuki, K. T.; Biyantoro, D.; Effendy, N.

2018-04-01

Yttrium oxide can be used as a dopant control rod of nuclear reactors in YSH material and superconductors. Yttrium oxide is obtained in the Xenotime mineral derived from byproduct of tin mining PT Timah Bangka which contain rare earth elements (REE) dominant Y, Dy, and Gd whose content respectively about 29.53%, 7.76%, and 2.58%. Both usage in the field of nuclear and non-nuclear science and technology is need to pure from the impurities. The presence of impurities in the yttrium oxide may affect the characteristic of the material and the efficiency of its use. Thus it needs to be separated by precipitation and extraction-stripping and calcination in the making of the oxide. However, to obtain higher levels of Yttrium oxide, it is necessary to determine the optimum conditions for its separation. The purpose of this research was to determine the optimum pH of precipitation, determine acid media and concentration optimum in extraction and stripping process and determine the efficiency of the separation of Y from REE concentrate. This research was conducted with pH variation in the precipitation process that pHs were 4 - 8, the difference of acid media for the extraction process, i.e., HNO3, HCl and H2SO4 with each concentration of 0,5 M; 1 M; 1,5 M; and 2 M and for stripping process were HNO3, HCl, and H2SO4 with each concentration of 1 M; 2M; and 3 M. Based on the result, the optimum pH of precipitation process was 6,5, the optimumacid media was HNO3 0,5 M, and for stripping process media was HNO3 3 M. The efficiency of precipitation process at pH 6,5 was 69,53 %, extraction process was 96.39% and stripping process was 4,50%. The separation process from precipitation to extraction had increased the purity and the highest efficiency recovery of Y was in the extraction process and obtained Y2O3 purer compared to the feed with the Y2O3 content of 92.87%.

Mott insulator-to-metal transition in yttrium-doped CaIrO₃.

PubMed

Gunasekera, J; Chen, Y; Kremenak, J W; Miceli, P F; Singh, D K

2015-02-11

We report on the study of insulator-to-metal transition in post-perovskite compound CaIrO3. It is discovered that a gradual chemical substitution of calcium by yttrium leads to the onset of strong metallic behavior in this compound. This observation is in stark contrast to BaIrO3, which preserves its Mott insulating behavior despite excess of the charge carriers due to yttrium doping. Magnetic measurements reveal that both compounds tend to exhibit magnetic character irrespective of the chemical substitution of Ca or Ba. We analyze these unusual observations in light of recent researches that suggest that CaIrO3 does not necessarily possess j = 1/2 ground state due to structural distortion. The insulator-to-metal transition in CaIrO3 will spur new researches to explore more exotic ground state, including superconductivity, in post-perovskite Mott insulators.

Reflectance, Optical Properties, and Stability of Molybdenum/Strontium and Molybdenum/Yttrium Multilayer Mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kjornrattanawanich, Benjawan

2002-09-01

The motivation of this work is to develop high reflectance normal-incidence multilayer mirrors in the 8-12 nm wavelength region for applications in astronomy and extreme ultraviolet lithography. To achieve this goal, Mo/Sr and Mo/Y multilayers were studied. These multilayers were deposited with a UHV magnetron sputtering system and their reflectances were measured with synchrotron radiation. High normal-incidence reflectances of 23% at 8.8 nm, 40.8% at 9.4 nm, and 48.3% at 10.5 nm were achieved. However, the reflectance of Mo/Sr multilayers decreased rapidly after exposure to air. Attempts to use thin layers of carbon to passivate the surface of Mo/Sr multilayers were unsuccessful. Experimental results on the refractive indexmore » $$\\tilde{n}$$ = 1-δ + iβ of yttrium and molybdenum in the 50-1300 eV energy region are reported in this work. This is the first time ever that values on the refractive index of yttrium are measured in this energy range. The absorption part β was determined through transmittance measurements. The dispersive part δ was calculated by means of the Kramers-Kronig formalism. The newly determined values of the refractive index of molybdenum are in excellent agreement with the published data. Those of yttrium are more accurate and contain fine structures around the yttrium M-absorption edges where Mo/Y multilayers operate. These improved sets of optical data lead to better design and modeling of the optical properties of Mo/Y multilayers. The reflectance quality of Mo/Y multilayers is dependent on their optical and structural properties. To correlate these properties with the multilayer reflectance, x-ray diffraction, Rutherford backscattering spectrometry, and transmission electron microscopy were used to analyze samples. Normal-incidence reflectances of 32.6% at 9.27 nm, 38.4% at 9.48 nm, and 29.6% at 9.46 nm were obtained from three representative Mo/Y multilayers which had about 0%, 25%, and 39% atomic oxygen assimilated in their

Optical bistability in erbium-doped yttrium aluminum garnet crystal combined with a laser diode.

PubMed

Maeda, Y

1994-01-10

Optical bistability was observed in a simple structure of an injection laser diode combined with an erbium-doped yttrium aluminum garnet crystal. Since a hysteresis characteristic exists in the relationship between the wavelength and the injection current of a laser diode, an optical memory function capable of holding the output status is confirmed. In addition, an optical signal inversion was caused by the decrease of transmission of the erbium-doped yttrium aluminum garnet crystal against the red shift (principally mode hopping) of the laser diode. It is suggested that the switching time of this phenomenon is the time necessary for a mode hopping by current injection.

Intra-articular radioactive yttrium and triamcinolone hexacetonide: an inconclusive trial. Arthritis and Rheumatism Council Multicentre Radiosynoviorthesis Trial Group.

PubMed

1984-08-01

A restricted sequential design multicentre controlled trial of yttrium-90 against triamcinolone intra-articularly was undertaken in patients with rheumatoid arthritis with knee involvement. The trial had to be discontinued because of dwindling recruitment over time. The reasons for this and other features contributing to an inconclusive outcome are noted. This experience lends little encouragement to the idea that yttrium-90 therapy is more or less advantageous than triamcinolone hexacetonide.

A comparative study of the luminescence properties of LYSO:Ce, LSO:Ce, GSO:Ce and BGO single crystal scintillators for use in medical X-ray imaging.

PubMed

Valais, I; Michail, C; David, S; Nomicos, C D; Panayiotakis, G S; Kandarakis, I

2008-06-01

The present study is a comparative investigation of the luminescence properties of (Lu,Y)(2)SiO(5):Ce (LYSO:Ce), Lu(2)SiO(5):Ce (LSO:Ce), Gd(2)SiO(5):Ce (GSO:Ce) and (Bi(4)Ge(3)O(12)) BGO single crystal scintillators under medical X-ray excitation. All scintillating crystals have dimensions of 10 x 10 x 10 mm(3) are non-hygroscopic exhibiting high radiation absorption efficiency in the energy range used in medical imaging applications. The comparative investigation was performed by determining the absolute luminescence efficiency (emitted light flux over incident X-ray exposure) in X-ray energies employed in general X-ray imaging (40-140 kV) and in mammographic X-ray imaging (22-49 kV). Additionally, light emission spectra of crystals at various X-ray energies were measured, in order to determine the spectral compatibility to optical photon detectors incorporated in medical imaging systems and the overall efficiency (effective efficiency) of a scintillator-optical detector combination. The light emission performance of LYSO:Ce and LSO:Ce scintillators studied was found very high for X-ray imaging.

Atomic layer deposition of zirconium silicate films using zirconium tetrachloride and tetra-n-butyl orthosilicate

NASA Astrophysics Data System (ADS)

Kim, Won-Kyu; Kang, Sang-Woo; Rhee, Shi-Woo; Lee, Nae-In; Lee, Jong-Ho; Kang, Ho-Kyu

2002-11-01

Atomic layer chemical vapor deposition of zirconium silicate films with a precursor combination of ZrCl4 and tetra-n-butyl orthosilicate (TBOS) was studied for high dielectric gate insulators. The effect of deposition conditions, such as deposition temperature, pulse time for purge and precursor injection on the deposition rate per cycle, and composition of the film were studied. At 400 °C, the growth rate saturated to 1.35 Å/cycle above 500 sccm of the argon purge flow rate. The growth rate, composition ratio ((Zr/Zr+Si)), and impurity contents (carbon and chlorine) saturated with the increase of the injection time of ZrCl4 and TBOS and decreased with the increased deposition temperature from 300 to 500 °C. The growth rate, composition ratio, carbon, and chlorine contents of the Zr silicate thin films deposited at 500 °C were 1.05 Å/cycle, 0.23, 1.1 at. %, and 2.1 at. %, respectively. It appeared that by using only zirconium chloride and silicon alkoxide sources, the content of carbon and chlorine impurities could not be lowered below 1%. It was also found that the incorporation rate of metal from halide source was lower than alkoxide source.

Kinetic characteristics of the luminescence decay for industrial yttrium-gadolinium-aluminium garnet based phosphors

NASA Astrophysics Data System (ADS)

Lisitsyn, V. M.; Stepanov, S. A.; Valiev, D. T.; Vishnyakova, E. A.; Abdullin, H. A.; Marhabaeva, A. A.; Tulegenova, A. T.

2016-02-01

The spectral and decay kinetic characteristics of pulse cathodoluminescence and photoluminescence of phosphors based on yttrium-gadolinium-aluminum garnet were investigated using pulsed optical time resolved spectroscopy.

Intra-articular radioactive yttrium and triamcinolone hexacetonide: an inconclusive trial. Arthritis and Rheumatism Council Multicentre Radiosynoviorthesis Trial Group.

PubMed Central

1984-01-01

A restricted sequential design multicentre controlled trial of yttrium-90 against triamcinolone intra-articularly was undertaken in patients with rheumatoid arthritis with knee involvement. The trial had to be discontinued because of dwindling recruitment over time. The reasons for this and other features contributing to an inconclusive outcome are noted. This experience lends little encouragement to the idea that yttrium-90 therapy is more or less advantageous than triamcinolone hexacetonide. PMID:6383234

Cobalt and Yttrium Modified TiO2 Nanotubes Based Dye-Sensitized Solar Cells for Solar-Energy Conversion

NASA Astrophysics Data System (ADS)

Shabanov, N. S.; Isaev, A. B.; Orudzhev, F. F.; Murliev, E. K.

2018-01-01

The solar-energy conversion in eosin-sensitized solar cells based on cobalt and yttrium modified TiO2 nanotubes has been studied.It is established that the doping with metal ions shifts the absorption edge for Co and Y doped titanium dioxide samples to longer and shorter wavelengths, respectively. The efficiency of solar energy conversion depends on the wide bandgap of the semiconductor anode and reaches a maximum (4.4%) for yttrium-doped TiO2 in comparison to that (4.1%) for pure titanium dioxide.

Polythermal investigation of viscosity of solution of metal carboxylates in VIK-grade mixed carboxylic acids: Yttrium and gadolinium carboxylates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mezhov, E.A.; Samatov, A.V.; Troyanovskii, L.V.

Kinematic viscosities have been measured for solutions of yttrium and gadolinium carboxylates in grade VIK mixed carboxylic acids (MCA). It has been established that the optimal fluidity of these metal carboxylate solutions for application to articles is reached at 333 K. A regression model has been developed to describe the concentration and temperature dependences of the viscosity of yttrium- and gadolinium-containing MCA solutions. 2 refs., 3 tabs.

Thermoelectric properties of the yttrium-doped ceramic oxide SrTiO3

NASA Astrophysics Data System (ADS)

Khan, Tamal Tahsin; Ur, Soon-Chul

2017-01-01

The doping dependence of the thermoelectric figure of merit, ZT, of the ceramic oxide SrTiO3 at high temperature has been studied. In this study, yttrium was used as the doping element. A conventional solid-state reaction method was used for the preparation of Y-doped SrTiO3. The doping level in SrTiO3 was controlled to be in the doping range of 2 - 10 mole%. Almost all the yttrium atoms incorporated into the SrTiO3 provided charge carriers, as was observed by using X-ray diffraction pattern. The relative densities of all the samples varied from 98.53% to 99.45%. The thermoelectric properties, including the electrical conductivity σ, Seebeck coefficient S, thermal conductivity k, and the figure of merit, ZT, were investigated at medium temperatures. The ZT value showed an obvious doping level dependence, in which a value as high as 0.18 is realized at 773 K for a doping of 8 mole%.

Ion beam irradiation of lanthanum and thorium-doped yttrium titanates

NASA Astrophysics Data System (ADS)

Lian, J.; Zhang, F. X.; Peters, M. T.; Wang, L. M.; Ewing, R. C.

2007-05-01

Y2Ti2O7 pyrochlores doped with La have been sintered at 1373 K for 12 h with the designed compositions of the (LaxY1-x)2Ti2O7 system (x = 0, 0.08, 0.5, and 1), and the phase compositions were analyzed by X-ray diffraction. Limited amounts of La were incorporated into yttrium titanate pyrochlore structure for La-doped samples; while, the end member composition of La2Ti2O7 formed a layered perovskite structure. Ion beam-induced amorphization occurred for all compositions in the (LaxY1-x)2Ti2O7 binary under 1 MeV Kr2+ irradiation at room temperature, and the critical amorphization dose decreased with increasing amounts of La3+. The critical amorphization temperatures for Y2Ti2O7, (La0.162Y0.838)2Ti2O7 and La2Ti2O7 were determined to be ∼780, 890 and 920 K, respectively. Th4+ and Fe3+-doped yttrium titanate pyrochlores were synthesized at 1373 K by sintering Y2Ti2O7 with (ThO2 + Fe2O3). Pyrochlore structures and the chemical compositions were primarily identified by the X-ray diffraction and energy dispersive X-ray (EDX) measurements. The lattice parameter and the critical amorphization dose (1 MeV Kr2+ at room temperature) increase for yttrium titanate pyrochlores with the addition of Th. The increasing 'resistance' to amorphization with less La and greater Th and Fe contents for (Y1-xLax)2Ti2O7 and Y2Ti2O7-Fe2O3-ThO2 systems, respectively, are consistent with the changes in the average ionic radius ratio at the A-sites and B-sites. These results suggest that the addition of lanthanides and actinides (e.g., Th, U, or Pu) will affect the structural stability, as well as the radiation response behavior of the pyrochlore structure-type.

Magnetocrystalline anisotropy of Fe2 + ion in silicon- or germanium-substituted yttrium iron garnet at zero temperature

NASA Astrophysics Data System (ADS)

Rudowicz, Czeslaw

1982-01-01

The present work reports the theoretical considerations of the magnetocrystalline anisotropy of ferrous ions induced by tetravalent dopants in yttrium iron garnet. Using the spin Hamiltonian developed earlier by us and the molecular field (h) approximation we derive the cubic anisotropy constants K1 and K2 at zero temperature. We adopt the Alben's et al. model of twelve inequivalent Fe2+ sites in silicon-substituted yttrium iron garnet. Results are given for h = 400, 300, 200 and the spin Hamiltonian parameters with the trigonal Δ = 300, 400, 500, 600, 700 and the nontrigonal crystal field parameter Γ = 200, 300 cm-1. The agreement with the experimental K1 and K2 is quite good. The discussion reveals that the properties of the far and near sites in the two-center model can now be theoretically explained. The theoretical ratios of K1(far) to K1(near) agree well with experiment. Thus our results speak in favor of the orbital singlet rather than the doublet model assumed previously for Fe2+ in silicon- or germanium-substituted yttrium iron garnets.

Influence of Yttrium Ion-Implantation on the Growth Kinetics and Micro-Structure of NiO Oxide Film

NASA Astrophysics Data System (ADS)

Jin, Huiming; Adriana, Felix; Majorri, Aroyave

2008-02-01

Isothermal and cyclic oxidation behaviours of pure and yttrium-implanted nickel were studied at 1000°C in air. Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) were used to examine the micro-morphology and structure of oxide scales formed on the nickel substrate. It was found that Y-implantation significantly improved the anti-oxidation ability of nickel in both isothermal and cyclic oxidizing experiments. Laser Raman microscopy was also used to study the stress status of oxide scales formed on nickel with and without yttrium. The main reason for the improvement in anti-oxidation of nickel was that Y-implantation greatly reduced the growing speed and grain size of NiO. This fine-grained NiO oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained a ridge character and a relatively low internal stress level. Hence yttrium ion-implantation remarkably enhanced the adhesion of protective NiO oxide scale formed on the nickel substrate.

Bioinspired, cysteamine-catalyzed co-silicification of (1H, 1H, 2H, 2HPerfluorooctyl) triethoxysilane and tetraethyl orthosilicate: formation of superhydrophobic surfaces.

PubMed

Park, Ji Hun; Kim, Ji Yup; Cho, Woo Kyung; Choi, Insung S

2014-03-01

Bioinspired silicification attracts a great deal of interest because of its physiologically relevant, mild conditions for hydrolysis and condensation of silica precursors, which makes the bioinspired approach superior to the conventional sol–gel process, particularly when dealing with biological entities. However, the morphological control of silica structures with incorporation of functional groups in the bioinspired silicilication has been unexplored. In this work, we co-silicificated (1H, 1H, 2H, 2H-perfluorooctyl)triethoxysilane and tetraethyl orthosilicate to investigate the morphological evolution of fluorinated silica structures in the cetyltrimethylammonium bromide-mediated, cysteamine-catalyzed silicification. The generated micrometer-long wormlike and spherical silica structures display superhydrophobicity after film formation. Interestingly, the measurement of dynamic water contact angles shows that the morphological difference leads to a different wetting state, either the self-cleaning or the pinning state of the superhydrophobic surface.

High-spin europium and gadolinium centers in yttrium-aluminum garnet

NASA Astrophysics Data System (ADS)

Vazhenin, V. A.; Potapov, A. P.; Asatryan, G. R.; Uspenskaya, Yu. A.; Petrosyan, A. G.; Fokin, A. V.

2016-08-01

Electron-spin resonance spectra of Eu2+ and Gd3+ centers substituting Y3+ ions in single-crystal yttrium-aluminum garnet have been studied and the parameters of their rhombic spin Hamiltonian have been determined. The fine-structure parameters of the above ions have been calculated in the superposition model disregarding changes in the angular coordinates of the ligand environment of the impurity defect thus demonstrating the necessity of taking these changes into account.

Electrolytic Deposition and Diffusion of Lithium onto Magnesium-9 Wt Pct Yttrium Bulk Alloy in Low-Temperature Molten Salt of Lithium Chloride and Potassium Chloride

NASA Astrophysics Data System (ADS)

Dong, Hanwu; Wu, Yaoming; Wang, Lidong; Wang, Limin

2009-10-01

The electrolytic deposition and diffusion of lithium onto bulk magnesium-9 wt pct yttrium alloy cathode in molten salt of 47 wt pct lithium chloride and 53 wt pct potassium chloride at 693 K were investigated. Results show that magnesium-yttrium-lithium ternary alloys are formed on the surface of the cathodes, and a penetration depth of 642 μm is acquired after 2 hours of electrolysis at the cathodic current density of 0.06 A·cm-2. The diffusion of lithium results in a great amount of precipitates in the lithium containing layer. These precipitates are the compound of Mg41Y5, which arrange along the grain boundaries and hinder the diffusion of lithium, and solid solution of yttrium in magnesium. The grain boundaries and the twins of the magnesium-9 wt pct yttrium substrate also have negative effects on the diffusion of lithium.

Radiographic Response to Yttrium-90 Radioembolization in Anterior Versus Posterior Liver Segments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibrahim, Saad M.; Lewandowski, Robert J.; Ryu, Robert K.

2008-11-15

The purpose of our study was to determine if preferential radiographic tumor response occurs in tumors located in posterior versus anterior liver segments following radioembolization with yttrium-90 glass microspheres. One hundred thirty-seven patients with chemorefractory liver metastases of various primaries were treated with yttrium-90 glass microspheres. Of these, a subset analysis was performed on 89 patients who underwent 101 whole-right-lobe infusions to liver segments V, VI, VII, and VIII. Pre- and posttreatment imaging included either triphasic contrast material-enhanced CT or gadolinium-enhanced MRI. Responses to treatment were compared in anterior versus posterior right lobe lesions using both RECIST and WHO criteria.more » Statistical comparative studies were conducted in 42 patients with both anterior and posterior segment lesions using the paired-sample t-test. Pearson correlation was used to determine the relationship between pretreatment tumor size and posttreatment tumor response. Median administered activity, delivered radiation dose, and treatment volume were 2.3 GBq, 118.2 Gy, and 1,072 cm{sup 3}, respectively. Differences between the pretreatment tumor size of anterior and posterior liver segments were not statistically significant (p = 0.7981). Differences in tumor response between anterior and posterior liver segments were not statistically significant using WHO criteria (p = 0.8557). A statistically significant correlation did not exist between pretreatment tumor size and posttreatment tumor response (r = 0.0554, p = 0.4434). On imaging follow-up using WHO criteria, for anterior and posterior regions of the liver, (1) response rates were 50% (PR = 50%) and 45% (CR = 9%, PR = 36%), and (2) mean changes in tumor size were -41% and -40%. In conclusion, this study did not find evidence of preferential radiographic tumor response in posterior versus anterior liver segments treated with yttrium-90 glass microspheres.« less

Radiographic response to yttrium-90 radioembolization in anterior versus posterior liver segments.

PubMed

Ibrahim, Saad M; Lewandowski, Robert J; Ryu, Robert K; Sato, Kent T; Gates, Vanessa L; Mulcahy, Mary F; Kulik, Laura; Larson, Andrew C; Omary, Reed A; Salem, Riad

2008-01-01

The purpose of our study was to determine if preferential radiographic tumor response occurs in tumors located in posterior versus anterior liver segments following radioembolization with yttrium-90 glass microspheres. One hundred thirty-seven patients with chemorefractory liver metastases of various primaries were treated with yttrium-90 glass microspheres. Of these, a subset analysis was performed on 89 patients who underwent 101 whole-right-lobe infusions to liver segments V, VI, VII, and VIII. Pre- and posttreatment imaging included either triphasic contrast material-enhanced CT or gadolinium-enhanced MRI. Responses to treatment were compared in anterior versus posterior right lobe lesions using both RECIST and WHO criteria. Statistical comparative studies were conducted in 42 patients with both anterior and posterior segment lesions using the paired-sample t-test. Pearson correlation was used to determine the relationship between pretreatment tumor size and posttreatment tumor response. Median administered activity, delivered radiation dose, and treatment volume were 2.3 GBq, 118.2 Gy, and 1,072 cm(3), respectively. Differences between the pretreatment tumor size of anterior and posterior liver segments were not statistically significant (p = 0.7981). Differences in tumor response between anterior and posterior liver segments were not statistically significant using WHO criteria (p = 0.8557). A statistically significant correlation did not exist between pretreatment tumor size and posttreatment tumor response (r = 0.0554, p = 0.4434). On imaging follow-up using WHO criteria, for anterior and posterior regions of the liver, (1) response rates were 50% (PR = 50%) and 45% (CR = 9%, PR = 36%), and (2) mean changes in tumor size were -41% and -40%. In conclusion, this study did not find evidence of preferential radiographic tumor response in posterior versus anterior liver segments treated with yttrium-90 glass microspheres.

Scanning-SQUID investigation of spin-orbit torque acting on yttrium iron garnet devices

NASA Astrophysics Data System (ADS)

Rosenberg, Aaron J.; Jermain, Colin L.; Aradhya, Sriharsha V.; Brangham, Jack T.; Nowack, Katja C.; Kirtley, John R.; Yang, Fengyuan; Ralph, Daniel C.; Moler, Kathryn A.

Successful manipulation of electrically insulating magnets, such as yttrium iron garnet, by by current-driven spin-orbit torques could provide a highly efficient platform for spintronic memory. Compared to devices fabricated using magnetic metals, magnetic insulators have the advantage of the ultra-low magnetic damping and the elimination of shunting currents in the magnet that reduce the torque efficiency. Here, we apply current in the spin Hall metal β-Ta to manipulate the magnetic orientation of micron-sized, electrically-insulating yttrium iron garnet devices. We do not observe spin-torque switching even for applied currents well above the critical current expected in a macrospin switching model. This suggests either inefficient transfer of spin torque at our Ta/YIG interface or a breakdown of the macrospin approximation. This work is supported by FAME, one of six centers of STARnet sponsored by MARCO and DARPA. The SQUID microscope and sensors were developed with support from the NSF-sponsored Center NSF-NSEC 0830228, and from NSF IMR-MIP 0957616.

Radiosynovectomy in haemophilic synovitis of elbows and ankles: Is the effectiveness of yttrium-90 and rhenium-186 different?

PubMed

Rodriguez-Merchan, E C; De La Corte-Rodriguez, H

2016-04-01

Radiosynovectomy (RS) reduces the number of haemarthroses and the synovial size in chronic haemophilic synovitis. The purpose of this study was to quantitatively compare the effectiveness of two types of RS (yttrium-90 vs. rhenium-186) in terms of the objective improvement of haemarthroses and synovial size. Seventy RSs were performed in 70 joints (44 elbows, 26 ankles) of 70 haemophiliacs diagnosed with chronic synovitis. Yttrium-90 was used in 21 joints and rhenium-186 was used in 49 joints. The mean patient age was 20.61 years. RS resulted in significant improvement in the three variables studied (six months before RS vs. six months after RS), namely in the number of episodes of haemarthrosis (67.8% improvement); the size of the synovium as measured by means of a clinical scale (43.8% improvement) and imaging techniques in millimetres (26.7% improvement). We did not find significant statistical differences between yttrium-90 and rhenium-186 regarding their efficacy. No correlation was found between the results and other variables: age, joint (ankle or elbow), presence or absence of radiological involvement, type of haemophilia (A or B), grade of haemophilia (mild, moderate or severe), previous haematological treatment (on demand or prophylaxis), and the presence or absence of inhibitor Yttrium-90 RS and rhenium-186 RS were equally effective in reducing the number of haemarthroses and the size of the synovium in ankles and elbows in the short-term (6 months). No correlation was found between the results and other patients' characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neodymium:yttrium-aluminum-garnet laser fusion of endarterectomy flaps.

PubMed

Humphrey, P W; Slocum, M M; Loy, T S; Silver, D

1995-07-01

This study evaluated the efficacy of neodymium:yttrium-aluminum-garnet laser welding of flaps in canine arteries and in securing the distal flap during human carotid endarterectomy. Endarterectomy flaps were created in both common carotid and both common femoral arteries in 12 dogs. The flaps were repaired with either the neodymium:yttrium-aluminum-garnet laser or with 6-0 polypropylene sutures. The arteries were removed after duplex scanning at either 7 or 28 days. Eighteen high carotid endarterectomy flaps in 16 patients have been subsequently secured with the laser welding technique. Laser repairs (125 +/- 19 joule) of the canine arteries were completed more quickly than suture repairs (mean 25 seconds vs 135 seconds, respectively; p < 0.04). Duplex ultrasonography revealed no discernable differences between the two groups of arteries. Arteries studied at 7 days revealed three microscopic flaps (two suture, one laser), more subintimal fibroblastic proliferation in suture than laser-repaired carotid arteries (3: 1, p = 0.0530), and similar amounts of inflammation in suture- and laser-repaired arteries. Arteries studied at 28 days revealed one microscopic intimal flap (suture-repaired); equal fibroblastic and inflammatory responses in suture- and laser-repaired vessels; and no evidence of laser thermal injury. Eighteen carotid endarterectomy flaps have been successfully fused with no immediate or long-term complications in 16 patients (follow-up of 0 to 24 months). Laser fusion appears to be a safe and effective method for securing distal carotid endarterectomy flaps.

Development of an LYSO based gamma camera for positron and scinti-mammography

NASA Astrophysics Data System (ADS)

Liang, H.-C.; Jan, M.-L.; Lin, W.-C.; Yu, S.-F.; Su, J.-L.; Shen, L.-H.

2009-08-01

In this research, characteristics of combination of PSPMTs (position sensitive photo-multiplier tube) to form a larger detection area is studied. A home-made linear divider circuit was built for merging signals and readout. Borosilicate glasses were chosen for the scintillation light sharing in the crossover region. Deterioration effect caused by the light guide was understood. The influences of light guide and crossover region on the separable crystal size were evaluated. According to the test results, a gamma camera with a crystal block of 90 × 90 mm2 covered area, composed of 2 mm LYSO crystal pixels, was designed and fabricated. Measured performances showed that this camera worked fine in both 511 keV and lower energy gammas. The light loss behaviour within the crossover region was analyzed and realized. Through count rate measurements, the 176Lu nature background didn't show severe influence on the single photon imaging and exhibited an amount of less than 1/3 of all the events acquired. These results show that with using light sharing techniques, combination of multiple PSPMTs in both X and Y directions to build a large area imaging detector is capable to be achieved. Also this camera design is feasible to keep both the abilities for positron and single photon breast imaging applications. Separable crystal size is 2 mm with 2 mm thick glass applied for the light sharing in current status.

Development of brain PET using GAPD arrays.

PubMed

Jung, Jin Ho; Choi, Yong; Hong, Key Jo; Kang, Jihoon; Hu, Wei; Lim, Hyun Keong; Huh, Yoonsuk; Kim, Sangsu; Jung, Jiwoong; Kim, Kyu Bom

2012-03-01

In recent times, there has been great interest in the use of Geiger-mode avalanche photodiodes (GAPDs) as scintillator readout in positron emission tomography (PET) detectors because of their advantages, such as high gain, compact size, low power consumption, and magnetic field insensitivity. The purpose of this study was to develop a novel PET system based on GAPD arrays for brain imaging. The PET consisted of 72 detector modules arranged in a ring of 330 mm diameter. Each PET module was composed of a 4 × 4 matrix of 3 × 3 × 20 mm(3) cerium-doped lutetium yttrium orthosilicate (LYSO) crystals coupled with a 4 × 4 array three-side tileable GAPD. The signals from each PET module were fed into preamplifiers using a 3 m long flat cable and then sent to a position decoder circuit (PDC), which output a digital address and an analog pulse of the interacted channel among 64 preamplifier signals transmitted from four PET detector modules. The PDC outputs were fed into field programmable gate array (FPGA)-embedded data acquisition (DAQ) boards. The analog signal was then digitized, and arrival time and energy of the signal were calculated and stored. The energy and coincidence timing resolutions measured for 511 keV gamma rays were 18.4 ± 3.1% and 2.6 ns, respectively. The transaxial spatial resolution and sensitivity in the center of field of view (FOV) were 3.1 mm and 0.32% cps/Bq, respectively. The rods down to a diameter of 2.5 mm were resolved in a hot-rod phantom image, and activity distribution patterns between the white and gray matters in the Hoffman brain phantom were well imaged. Experimental results indicate that a PET system can be developed using GAPD arrays and the GAPD-based PET system can provide high-quality PET imaging.

Antibacterial and antibiofilm properties of yttrium fluoride nanoparticles

PubMed Central

Lellouche, Jonathan; Friedman, Alexandra; Gedanken, Aharon; Banin, Ehud

2012-01-01

Antibiotic resistance has prompted the search for new agents that can inhibit bacterial growth. Moreover, colonization of abiotic surfaces by microorganisms and the formation of biofilms is a major cause of infections associated with medical implants, resulting in prolonged hospitalization periods and patient mortality. In this study we describe a water-based synthesis of yttrium fluoride (YF3) nanoparticles (NPs) using sonochemistry. The sonochemical irradiation of an aqueous solution of yttrium (III) acetate tetrahydrate [Y(Ac)3 · (H2O)4], containing acidic HF as the fluorine ion source, yielded nanocrystalline needle-shaped YF3 particles. The obtained NPs were characterized by scanning electron microscopy and X-ray elemental analysis. NP crystallinity was confirmed by electron and powder X-ray diffractions. YF3 NPs showed antibacterial properties against two common bacterial pathogens (Escherichia coli and Staphylococcus aureus) at a μg/mL range. We were also able to demonstrate that antimicrobial activity was dependent on NP size. In addition, catheters were surface modified with YF3 NPs using a one-step synthesis and coating process. The coating procedure yielded a homogeneous YF3 NP layer on the catheter, as analyzed by scanning electron microscopy and energy dispersive spectroscopy. These YF3 NP-modified catheters were investigated for their ability to restrict bacterial biofilm formation. The YF3 NP-coated catheters were able to significantly reduce bacterial colonization compared to the uncoated surface. Taken together, our results highlight the potential to further develop the concept of utilizing these metal fluoride NPs as novel antimicrobial and antibiofilm agents, taking advantage of their low solubility and providing extended protection. PMID:23152681

Maintaining High Strength in Mg-LPSO Alloys with Low Yttrium Content Using Severe Plastic Deformation.

PubMed

Garces, Gerardo; Cabeza, Sandra; Barea, Rafael; Pérez, Pablo; Adeva, Paloma

2018-05-05

Alternative processing routes such as powder metallurgy, the extrusion of recycled chips, or equal channel angular pressing (ECAP) have been considered for effective methods of maintaining the high mechanical strength of Mg-Y-Zn alloys containing long-period stacking ordered structures with respect to the alloy processed by the conventional extrusion of as-cast ingots with the advantage of minimizing the yttrium content. A yield stress similar to that found for extruded Mg 97 Y₂Zn₁ alloy can be attained with only half of the usual yttrium and zinc additions thanks to the grain refinement induced by ECAP processing. The properties of Mg 98.5 Y₁Zn 0.5 subjected to ECAP are maintained up to 200 °C, but superplastic behavior is found above this temperature when the alloy is processed through a powder metallurgy route.

Special features of changes in the structure and mechanical properties of oxygen-free pure and yttrium-alloyed copper after vacuum induction remelting

NASA Astrophysics Data System (ADS)

Kamyshanchenko, N. V.; Galtsev, A. V.; Durykhin, M. I.; Neklyudov, I. M.; Borts, B. V.; Shevchenko, S. V.

2011-03-01

Properties of oxygen-free copper with a microadditive of yttrium and without it are studied after vacuum induction remelting. The ingots are subjected to intense hot pressing and subsequent rolling to various degrees of reduction. The effects of the annealing temperature on the structure and of the anisotropy of the structure on the strength properties of the copper are determined. The properties of copper with an additive of yttrium and without it are compared.

Magneto-optical properties of cerium substituted yttrium iron garnet films with reduced thermal budget for monolithic photonic integrated circuits.

PubMed

Goto, Taichi; Onbaşlı, Mehmet C; Ross, C A

2012-12-17

Thin films of polycrystalline cerium substituted yttrium iron garnet (CeYIG) were grown on an yttrium iron garnet (YIG) seed layer on Si and Si-on-insulator substrates by pulsed laser deposition, and their optical and magneto-optical properties in the near-IR region were measured. A YIG seed layer of ~30 nm thick processed by rapid thermal anneal at 800°C provided a virtual substrate to promote crystallization of the CeYIG. The effect of the thermal budget of the YIG/CeYIG growth process on the film structure, magnetic and magnetooptical properties was determined.

Spectroscopic investigation of the Cr to Tm energy transfer in Yttrium Aluminum Garnet (YAG) crystals

NASA Technical Reports Server (NTRS)

Dibartolo, B.

1988-01-01

New and interesting schemes have recently been considered for the efficient operation of solid-state ionic laser systems. Often the available data on these systems were obtained only because they seemed directly related to the laser performance and provide no insight into the physical processes. A more systematic approach is desirable, where more attention is devoted to the elementary basic processes and to the nature of the mechanisms at work. It is with this aim that we have undertaken the present study. Yttrium Aluminum Garnet (Y4Al5O12), called YAG, has two desirable properties as host for rare earth impurities: (1) trivalent rare earth ions can replace the yttrium without any charge compensation problem, and (2) YAG crystals have high cutoff energies. The results of measurements and calculations indicate that the Cr(3+) ion in YAG can be used to sensitize efficiently the Tm(3+) ion.

Yttrium oxide based three dimensional metamaterials for visible light cloaking

NASA Astrophysics Data System (ADS)

Rai, Pratyush; Kumar, Prashanth S.; Varadan, Vijay K.; Ruffin, Paul; Brantley, Christina; Edwards, Eugene

2014-04-01

Metamaterial with negative refractive index is the key phenomenon behind the concept of a cloaking device to hide an object from light in visible spectrum. Metamaterials made of two and three dimensional lattices of periodically placed electromagnetic resonant cells can achieve absorption and propagation of incident electromagnetic radiation as confined electromagnetic fields confined to a waveguide as surface plasmon polaritons, which can be used for shielding an object from in-tune electromagnetic radiation. The periodicity and dimensions of resonant cavity determine the frequency, which are very small as compared to the wavelength of incident light. Till now the phenomena have been demonstrated only for lights in near infrared spectrum. Recent advancements in fabrication techniques have made it possible to fabricate array of three dimensional nanostructures with cross-sections as small as 25 nm that are required for negative refractive index for wavelengths in visible light spectrum of 400-700 nm and for wider view angle. Two types of metamaterial designs, three dimensional concentric split ring and fishnet, are considered. Three dimensional structures consisted of metal-dielectric-metal stacks. The metal is silver and dielectric is yttrium oxide, other than conventional materials such as FR4 and Duroid. High κ dielectric and high refractive index as well as large crystal symmetry of Yttrium oxide has been investigated as encapsulating medium. Dependence of refractive index on wavelength and bandwidth of negative refractive index region are analyzed for application towards cloaking from light in visible spectrum.

Preparation and morphology, magnetic properties of yttrium iron garnet nanodot arrays on Gd3Ga5O12 substrate

NASA Astrophysics Data System (ADS)

Xu, Zhiwang; Zheng, Hui; Han, Mangui

2017-07-01

In this work, yttrium iron garnet nanodot array has been deposited on Gd3Ga5O12 substrate by pulsed laser deposition through an ultrathin alumina mask. The morphology and magnetic properties of YIG nanodot array have been investigated. Scanning electron microscopy displays the prepared nanodot array has a sharp distribution in diameter centered at 330 nm with standard deviation of 20 nm. X-ray diffraction θ-2θ and pole figure analysis show the yttrium iron garnet nanodot array has oriented growth. Moreover, typical hysteresis loops and ferromagnetic resonance spectra display larger coercivity and multi-resonance peaks which are ascribed to this unique structure.

Reflection of antiferromagnetic vortices on a supersonic domain wall in yttrium orthoferrite

NASA Astrophysics Data System (ADS)

Chetkin, M. V.; Kurbatova, Yu. N.; Shapaeva, T. B.; Borschegovsky, O. A.

2007-04-01

Reflection of solitary flexural waves propagating in a supersonic domain wall of yttrium orthoferrite from the domain wall part moving with the transverse-sound velocity is observed experimentally. This observation confirms that such a reflection of a solitary flexural wave leads to a change in the sign of the topological charge of the antiferromagnetic vortex accompanied by this wave, which proves a direct relationship between these two objects.

Thermo-optical characteristics and concentration quenching effects in Nd3+doped yttrium calcium borate glasses

NASA Astrophysics Data System (ADS)

Santos, D. R. S.; Santos, C. N.; de Camargo, A. S. S.; Silva, W. F.; Santos, W. Q.; Vermelho, M. V. D.; Astrath, N. G. C.; Malacarne, L. C.; Li, M. S.; Hernandes, A. C.; Ibanez, A.; Jacinto, C.

2011-03-01

In this work we present a comprehensive study of the spectroscopic and thermo-optical properties of a set of samples with composition xNd2O3-(5-x)Y2O3-40CaO-55B2O3 (0 ≤ x ≤ 1.0 mol%). Their fluorescence quantum efficiency (η) values were determined using the thermal lens technique and the dependence on the ionic concentration was analyzed in terms of energy transfer processes, based on the Förster-Dexter model of multipolar ion-ion interactions. A maximum η = 0.54 was found to be substantially higher than for yttrium aluminoborate crystals and glasses with comparable Nd3+ content. As for the thermo-optical properties of yttrium calcium borate, they are comparable to other well-known laser glasses. The obtained energy transfer microparameters and the weak dependence of η on the Nd3+ concentration with a high optimum Nd3+ concentration put this system as a strong candidate for photonics applications.

Emergence of microstructure and oxygen diffusion in yttrium-stabilized cubic zirconia

NASA Astrophysics Data System (ADS)

Yang, C.; Trachenko, K.; Hull, S.; Todorov, I. T.; Dove, M. T.

2018-05-01

Large-scale molecular dynamics simulations have been used to study the microstructure in Y-doped ZrO2. From simulations performed as a function of composition the dependence of microstructure on composition is quantified, showing how it is formed from two coexisting phases, and the transformation to the stabilized cubic form is observed at higher concentrations of yttrium and higher temperatures. The effect of composition and temperature on oxygen diffusion is also studied, showing strong correlations between microstructure and diffusion.

High-Performance Pyrochlore-Type Yttrium Ruthenate Electrocatalyst for Oxygen Evolution Reaction in Acidic Media

DOE PAGES

Kim, Jaemin; Shih, Pei-Chieh; Tsao, Kai-Chieh; ...

2017-07-27

Development of acid-stable electrocatalysts with low overpotential for oxygen evolution reaction (OER) is a major challenge to produce hydrogen directly from water. We report in this paper a pyrochlore yttrium ruthenate (Y 2Ru 2O 7-δ) electrocatalyst that has significantly enhanced performance toward OER in acid media over the best-known catalysts, with an onset overpotential of 190 mV and high stability in 0.1 M perchloric acid solution. X-ray absorption near-edge structure (XANES) indicates Y 2Ru 2O 7-δ electrocatalyst had a low valence state that favors the high OER activity. Density functional theory (DFT) calculation shows this pyrochlore has lower band centermore » energy for the overlap between Ru 4d and O 2p orbitals and is therefore more stable Ru–O bond than RuO 2, highlighting the effect of yttrium on the enhancement in stability. Finally, the Y 2Ru 2O 7-δ pyrochlore is also free of expensive iridium metal and thus is a cost-effective candidate for practical applications.« less

High-Performance Pyrochlore-Type Yttrium Ruthenate Electrocatalyst for Oxygen Evolution Reaction in Acidic Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jaemin; Shih, Pei-Chieh; Tsao, Kai-Chieh

Development of acid-stable electrocatalysts with low overpotential for oxygen evolution reaction (OER) is a major challenge for the production of hydrogen directly from water. We report in this paper a pyrochlore yttrium ruthenate (Y2Ru2O7-δ) electrocatalyst that has significantly enhanced performance towards OER in acid media over the best-known catalysts, with an onset overpotential of 190 mV and high stability in 0.1-M perchloric acid solution. X-ray absorption near-edge structure (XANES) indicates Y2Ru2O7-δ electrocatalyst had a low valence state that favors the high OER activity. Density functional theory (DFT) calculation shows this pyrochlore has lower band center energy for the overlap betweenmore » Ru 4d and O 2p orbitals and therefore more stable Ru-O bond than RuO2, highlighting the effect of yttrium on the enhancement in stability. The Y2Ru2O7-δ pyrochlore is also free of expensive iridium metal, thus a cost-effective candidate for practical applications.« less

High-Performance Pyrochlore-Type Yttrium Ruthenate Electrocatalyst for Oxygen Evolution Reaction in Acidic Media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jaemin; Shih, Pei-Chieh; Tsao, Kai-Chieh

Development of acid-stable electrocatalysts with low overpotential for oxygen evolution reaction (OER) is a major challenge to produce hydrogen directly from water. We report in this paper a pyrochlore yttrium ruthenate (Y 2Ru 2O 7-δ) electrocatalyst that has significantly enhanced performance toward OER in acid media over the best-known catalysts, with an onset overpotential of 190 mV and high stability in 0.1 M perchloric acid solution. X-ray absorption near-edge structure (XANES) indicates Y 2Ru 2O 7-δ electrocatalyst had a low valence state that favors the high OER activity. Density functional theory (DFT) calculation shows this pyrochlore has lower band centermore » energy for the overlap between Ru 4d and O 2p orbitals and is therefore more stable Ru–O bond than RuO 2, highlighting the effect of yttrium on the enhancement in stability. Finally, the Y 2Ru 2O 7-δ pyrochlore is also free of expensive iridium metal and thus is a cost-effective candidate for practical applications.« less

Yttrium 90 ibritumomab tiuxetan radioimmunotherapy for relapsed or refractory low-grade non-Hodgkin's lymphoma.

PubMed

Gordon, Leo I; Witzig, Thomas E; Wiseman, Greg A; Flinn, Ian W; Spies, Stewart S; Silverman, Daniel H; Emmanuolides, Christos; Cripe, Larry; Saleh, Mansoor; Czuczman, Myron S; Olejnik, Teresa; White, Christine A; Grillo-López, Antonio J

2002-02-01

The treatment of malignant lymphoma has improved over the past 20 years, but the majority of patients are not cured. New modalities using targeted therapy based on new information in molecular biology and immunology hold promise for better outcomes with less toxicity. We review data on the use of radiolabeled monoclonal antibodies directed against the CD20 antigen on malignant B cells. We discuss the major radionuclides available, iodine 131 ( 131 I), tositumomab, and yttrium 90 ( 90 Y) ibritumomab tiuxetan (Zevalin; IDEC Pharmaceuticals, San Diego, CA) and present data on new approaches in labeling antibodies that have facilitated their use. Clinical trial data with the yttrium-labeled antibodies are discussed. The use of dosimetry as a means for predicting toxicity is discussed, and the questions of long-term toxicity (late effects) are addressed. These targeted approaches to the treatment of malignancy, and lymphoma in particular, hold great promise. Semin Oncol 29 (suppl 2):87-92. Copyright © 2002 by W.B. Saunders Company. Copyright © 2002 W.B. Saunders Company. All rights reserved.

Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.

1992-01-01

A ceramic composition composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to aobut 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness.

Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

DOEpatents

Holcombe, C.E.; Dykes, N.L.

1992-04-28

A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness. No Drawings

Electric, Magnetic, and Magnetoelectric Properties of Yttrium-Containing BaY0.025Ti0.9625O3-SrFe12O19 Composite

NASA Astrophysics Data System (ADS)

Rather, Mehraj ud Din; Samad, Rubiya; Want, Basharat

2018-03-01

The physical properties of BaY0.025Ti0.9625O3, SrFe12O19, and 0.90BaY0.025Ti0.9625O3-0.10 SrFe12O19 composite have been studied. The proposed composite was synthesized by solid-state reaction method from yttrium barium titanate processed by solid-state reaction and strontium hexaferrite obtained by a sol-gel process. Microstructural analysis revealed monophasic grains for yttrium barium titanate phase, while loosely packed biphasic structure was observed for the composite. Powder x-ray analysis showed that the individual phases retained their crystal structure in the composite, without formation of any new additional phase. Measurement of magnetic hysteresis loops at room temperature indicated that the magnetic parameters of the composite were diluted by the presence of the ferroelectric phase. The ferroelectric hysteresis of yttrium barium titanate confirmed the ferroelectric transition at 119°C. Meanwhile, the symmetrical ferroelectric loops observed at different fields established the ferroelectric nature of the composite. Improved dielectric properties and low dielectric losses were observed due to yttrium doping in the composite. The diffuseness of the ferroelectric transitions for the composite was confirmed by the Curie-Weiss law. Activation energy calculations revealed the charge-hopping conduction mechanism in the composite. Magnetodielectric studies confirmed that the overall magnetocapacitance in the composite exhibited combined effects of magnetoresistance and magnetoelectric coupling.

Understanding microstrain anisotropy in yttrium oxide synthesized by sol-gel route

NASA Astrophysics Data System (ADS)

Murugesan, S.; Thirumurugesan, R.; Parameswaran, P.

2018-04-01

Yttrium oxide was synthesized by wet chemical route and calcined at various temperatures. On x-ray diffraction analysis of the material using Williamson-Hall analysis followed by Rietveld analysis indicates that the powder exists in nano crystallite size with lattice strain. The spherical harmonics analysis model of microstrain indicates the presence of strain anisotropy. The change in crystal structure lattice parameter, atomic coordinates of Y, O in yttria and the bond length analysis of the calcined powder reveals the presence of oxygen vacancies in the system.

Surface modification of a polyimide gate insulator with an yttrium oxide interlayer for aqueous-solution-processed ZnO thin-film transistors.

PubMed

Jang, Kwang-Suk; Wee, Duyoung; Kim, Yun Ho; Kim, Jinsoo; Ahn, Taek; Ka, Jae-Won; Yi, Mi Hye

2013-06-11

We report a simple approach to modify the surface of a polyimide gate insulator with an yttrium oxide interlayer for aqueous-solution-processed ZnO thin-film transistors. It is expected that the yttrium oxide interlayer will provide a surface that is more chemically compatible with the ZnO semiconductor than is bare polyimde. The field-effect mobility and the on/off current ratio of the ZnO TFT with the YOx/polyimide gate insulator were 0.456 cm(2)/V·s and 2.12 × 10(6), respectively, whereas the ZnO TFT with the polyimide gate insulator was inactive.

Synthesis and photoluminescence of EuII in barium zinc orthosilicate: a novel green color emitting phosphor for white-LEDs.

PubMed

Kasturi, S; Sivakumar, V; Varadaraju, U V

2017-05-01

A series of Eu 2+ -activated barium orthosilicates (BaZnSiO 4 ) were synthesized using a high-temperature solid-state reaction. A photoluminescence excitation study of Eu 2 + shows a broad absorption band in the range of 270-450 nm, with multiple absorption peak maxima (310, 350 and 400 nm) due to 4f-5d electronic transition. The emission spectra of all the compositions show green color emission (in the spectral region 450-550 nm with a peak maximum at 502 nm and a shoulder at ~ 490 nm) with appropriate Comission Internationale de l'Eclairage (CIE) color coordinates. The two emission peaks are due to the presence of Eu 2 + in two different Ba sites in the BaZnSiO 4 host lattice. The energy transfers between the Eu 2 + ions in BaZnSiO 4 host are elucidated from the critical concentration quenching data based on the electronic multipolar interaction. All Eu 2 + -activated BaZnSiO 4 phosphor materials can be efficiently excited in the ultraviolet (UV) to near UV-region (270-420 nm), making them attractive candidate as a green phosphor for solid state lighting-white light-emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.

Thermodynamic Functions of Yttrium Trifluoride and Its Dimer in the Gas Phase

NASA Astrophysics Data System (ADS)

Osina, E. L.; Kovtun, D. M.

2018-05-01

New calculations of the functions for YF3 and Y2F6 in the gas phase using quantum-chemical calculations by MP2 and CCSD(T) methods are performed in connection with the ongoing work on obtaining reliable thermodynamic data of yttrium halides. The obtained values are entered in the database of the IVTANTERMO software complex. Equations approximating the temperature dependence of the reduced Gibbs energy in the T = 298.15-6000 K range of temperatures are presented.

Hepatic Abscess After Yttrium-90 Radioembolization for Islet-Cell Tumor Hepatic Metastasis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mascarenhas, Neil B., E-mail: neilmascarenhas1@gmail.co; Mulcahy, Mary F.; Lewandowski, Robert J.

2010-06-15

Infectious complications after yttrium-90 (y-90) radioembolization of hepatic tumors are rare. Most reports describe hepatic abscesses as complications of other locoregional therapies, such as transcatheter arterial embolization or chemoembolization. These usually occur in patients with a history of biliary intervention and present several weeks after treatment. We report a case of hepatic abscess formed immediately after y-90 radioembolization of a hepatic metastasis in a patient who had no history of previous biliary instrumentation.

A PET Design Based on SiPM and Monolithic LYSO Crystals: Performance Evaluation

NASA Astrophysics Data System (ADS)

González, Antonio J.; Aguilar, Albert; Conde, Pablo; Hernández, Liczandro; Moliner, Laura; Vidal, Luis F.; Sánchez, Filomeno; Sánchez, Sebastián; Correcher, Carlos; Molinos, César; Barberá, Julio; Lankes, Konrad; Junge, Sven; Bruckbauer, Thomas; Bruyndonckx, Peter; Benlloch, Jose M.

2016-10-01

A new small animal PET based on SiPM and monolithic LYSO crystals has been developed. Eight detector modules form the PET ring, each mounting an array of 12 × 12 SiPMs coupled to a readout providing the summed signals of the pixels on each of the 12 rows and 12 columns of the SiPM array. This design makes it possible to accurately determine the centroid of the scintillation light distribution with about 1.6 mm full width at half maximum (FWHM) resolution without correction for the 1 mm source size, and the photon depth of interaction (DOI) with nearly 2 mm FWHM. This single ring PET system has a homogeneous spatial resolution across the entire 80 mm transaxial field of view (FOV) of about 1 mm FWHM. The noise equivalent count rate (NECR) peak is estimated to occur at around 39.2 MBq with a rate of approximately 82.7 kcps for the mouse-like phantom and 22 kcps at 48.1 MBq for the rat-like phantom. Following the NEMA protocol, the peak absolute sensitivity in the center of the FOV is 2.8% for a 30% peak energy window. A pilot test injecting NaF to a mouse of 20 grams is also presented. Finally, the PET ring has been tested in front of a high field 15.2 T Magnetic Resonance (MR). No significant variation on energy and spatial resolution across the FOV has been observed due to the presence of the magnetic field.

Tungsten - Yttrium Based Nuclear Structural Materials

NASA Astrophysics Data System (ADS)

Ramana, Chintalapalle; Chessa, Jack; Martinenz, Gustavo

2013-04-01

The challenging problem currently facing the nuclear science community in this 21st century is design and development of novel structural materials, which will have an impact on the next-generation nuclear reactors. The materials available at present include reduced activation ferritic/martensitic steels, dispersion strengthened reduced activation ferritic steels, and vanadium- or tungsten-based alloys. These materials exhibit one or more specific problems, which are either intrinsic or caused by reactors. This work is focussed towards tungsten-yttrium (W-Y) based alloys and oxide ceramics, which can be utilized in nuclear applications. The goal is to derive a fundamental scientific understanding of W-Y-based materials. In collaboration with University of Califonia -- Davis, the project is designated to demonstrate the W-Y based alloys, ceramics and composites with enhanced physical, mechanical, thermo-chemical properties and higher radiation resistance. Efforts are focussed on understanding the microstructure, manipulating materials behavior under charged-particle and neutron irradiation, and create a knowledge database of defects, elemental diffusion/segregation, and defect trapping along grain boundaries and interfaces. Preliminary results will be discussed.

Dielectric properties and activation behavior of gadolinium doped nanocrystalline yttrium chromite

NASA Astrophysics Data System (ADS)

Sinha, R.; Basu, S.; Meikap, A. K.

2018-04-01

Gadolinium doped Yttrium Chromite nanoparticles are synthesized following sol-gel method. The formation of the nanoparticles are confirmed by XRD and TEM measurements. Dielectric permittivity and dielectric loss are estimated within the temperature range 298K to 523K and in the frequency range 20 Hz to 1 MHz. Dielectric permittivity follows the power law ɛ'(f) ∝ Tm. It is observed that the temperature exponent m increases with the decreasing frequency. The temperature variation of resistivity shows that the samples have semiconducting behavior. The activation energy is also measured.

Determination of strontium-90 from direct separation of yttrium-90 by solid phase extraction using DGA Resin for seawater monitoring.

PubMed

Tazoe, Hirofumi; Obata, Hajime; Yamagata, Takeyasu; Karube, Zin'ichi; Nagai, Hisao; Yamada, Masatoshi

2016-05-15

It is important for public safety to monitor strontium-90 in aquatic environments in the vicinity of nuclear related facilities. Strontium-90 concentrations in seawater exceeding the background level have been observed in accidents of nuclear facilities. However, the analytical procedure for measuring strontium-90 in seawater is highly demanding. Here we show a simple and high throughput analytical technique for the determination of strontium-90 in seawater samples using a direct yttrium-90 separation. The DGA Resin is used to determine the abundance of strontium-90 by detecting yttrium-90 decay (beta-emission) in secular equilibrium. The DGA Resin can selectively collect yttrium-90 and remove naturally occurring radionuclides such as (40)K, (210)Pb, (214)Bi, (238)U, and (232)Th and anthropogenic radionuclides such as (140)Ba, and (140)La. Through a sample separation procedure, a high chemical yield of yttrium-90 was achieved at 95.5±2.3%. The result of IAEA-443 certified seawater analysis (107.7±3.4 mBq kg(-1)) was in good agreement with the certified value (110±5 mBq kg(-1)). By developed method, we can finish analyzing 8 samples per day after achieving secular equilibrium, which is a reasonably fast throughput in actual seawater monitoring. By processing 3 L of seawater sample and applying a counting time of 20 h, minimum detectable activity can be as low as 1.5 mBq kg(-1), which could be applied to monitoring for the contaminated marine environment. Reproducibility was found to be 3.4% according to 10 independent analyses of natural seawater samples from the vicinity of the Fukushima Daiichi Nuclear Power Plant in September 2013. Copyright © 2016 Elsevier B.V. All rights reserved.

One-step synthesis of layered yttrium hydroxides in immiscible liquid-liquid systems: Intercalation of sterically-bulky hydrophobic organic anions and doping of europium ions

NASA Astrophysics Data System (ADS)

Watanabe, Mebae; Fujihara, Shinobu

2014-02-01

Inorganic-organic layered rare-earth compounds were synthesized on the basis of a biphasic liquid-liquid system in one pot. Layered yttrium hydroxides (LYHs) were chosen as a host material for the intercalation of hydrophobic organic guest anions such as benzoate, sebacate, or laurate. In a typical synthesis, an organic phase dissolving carboxylic acid was placed in contact with an equal amount of an aqueous phase dissolving yttrium nitrate n-hydrate and urea. At elevated temperatures up to 80 °C, urea was hydrolyzed to release hydroxyl anions which were used to form yttrium hydroxide layers. LYHs were then precipitated with the intercalation of carboxylate anions delivered from the organic phase under the distribution law. The structure and the morphology of the LYHs could be modulated by the intercalated anions. Doped with Eu3+ ions, the LYHs exhibited red photoluminescence which was enhanced by the intercalated anions due to the antenna effect.

Rare Earth Doped Yttrium Aluminum Garnet (YAG) Selective Emitters

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Pal, AnnaMarie T.; Patton, Martin O.; Jenkins, Phillip P.

1999-01-01

As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study presents a spectral emittance model for films and cylinders of rare earth doped yttrium aluminum garnets. Good agreement between experimental and theoretical film spectral emittances was found for erbium and holmium aluminum garnets. Spectral emittances of films are sensitive to temperature differences across the film. For operating conditions of interest, the film emitter experiences a linear temperature variation whereas the cylinder emitter has a more advantageous uniform temperature. Emitter efficiency is also a sensitive function of temperature. For holminum aluminum garnet film the efficiency is 0.35 at 1446K but only 0.27 at 1270 K.

Availability of yttrium-90 from strontium-90: a nuclear medicine perspective.

PubMed

Chakravarty, Rubel; Dash, Ashutosh; Pillai, M R A

2012-12-01

Yttrium-90 (T(½) 64.1 hours, E(βmax)=2.28 MeV) is a pure β⁻ particle emitting radionuclide with well-established applications in targeted therapy. There are several advantages of ⁹⁰Y as a therapeutic radionuclide. It has a suitable physical half-life (∼64 hours) and decays to a stable daughter product ⁹⁰Zr by emission of high-energy β⁻ particles. Yttrium has a relatively simple chemistry and its suitability for forming complexes with a variety of chelating agents is well established. The ⁹⁰Sr/⁹⁰Y generator is an ideal source for the long-term continuous availability of no-carrier-added ⁹⁰Y suitable for the preparation of radiopharmaceuticals for radionuclide therapy. The parent radionuclide ⁹⁰Sr, which is a long-lived fission product, is available in large quantities from spent fuel. Several useful technologies have been developed for the preparation of ⁹⁰Sr/⁹⁰Y generators. There are several well-established radiopharmaceuticals based on monoclonal antibodies, peptides, and particulates labeled with ⁹⁰Y, that are in regular use for the treatment of some forms of primary cancers and arthritis. At present, there are no generators for the elution of ⁹⁰Y that can be set up in a hospital radiopharmacy. The radionuclide is procured from manufacturers and the radiopharmaceuticals are formulated on site. This article reviews the development of ⁹⁰Sr/⁹⁰Y generator and the development of ⁹⁰Y radiopharmaceuticals.

A Lower-Cost High-Resolution LYSO Detector Development for Positron Emission Mammography (PEM)

PubMed Central

Ramirez, Rocio A.; Zhang, Yuxuan; Liu, Shitao; Li, Hongdi; Baghaei, Hossain; An, Shaohui; Wang, Chao; Jan, Meei-Ling; Wong, Wai-Hoi

2010-01-01

In photomultiplier-quadrant-sharing (PQS) geometry for positron emission tomography applications, each PMT is shared by four blocks and each detector block is optically coupled to four round PMTs. Although this design reduces the cost of high-resolution PET systems, when the camera consists of detector panels that are made up of square blocks, half of the PMT’s sensitive window remains unused at the detector panel edge. Our goal was to develop a LYSO detector panel which minimizes the unused portion of the PMTs for a low-cost, high-resolution, and high-sensitivity positron emission mammography (PEM) camera. We modified the PQS design by using elongated blocks at panel edges and square blocks in the inner area. For elongated blocks, symmetric and asymmetrical reflector patterns were developed and PQS and PMT-half-sharing (PHS) arrangements were implemented in order to obtain a suitable decoding. The packing fraction was 96.3% for asymmetric block and 95.5% for symmetric block. Both of the blocks have excellent decoding capability with all crystals clearly identified, 156 for asymmetric and 144 for symmetric and peak-to-valley ratio of 3.0 and 2.3 respectively. The average energy resolution was 14.2% for the asymmetric block and 13.1% for the symmetric block. Using a modified PQS geometry and asymmetric block design, we reduced the unused PMT region at detector panel edges, thereby increased the field-of-view and the overall detection sensitivity and minimized the undetected breast region near the chest wall. This detector design and using regular round PMT allowed building a lower-cost, high-resolution and high-sensitivity PEM camera. PMID:20485510

Spin waves in micro-structured yttrium iron garnet nanometer-thick films

DOE PAGES

Jungfleisch, Matthias B.; Zhang, Wei; Jiang, Wanjun; ...

2015-03-24

Here, we investigated the spin-wave propagation in a micro-structured yttrium iron garnet waveguide of 40 nm thickness. Utilizing spatially-resolved Brillouin light scattering microscopy, an exponential decay of the spinwave amplitude of 10 μm was observed. This leads to an estimated Gilbert damping constant of α = (8.79 ± 0.73) x 10 $-$4, which is larger than damping values obtained through ferromagnetic resonance measurements in unstructured films. Furthermore, we compared the theoretically calculated spatial interference of waveguide modes to the spin-wave pattern observed experimentally by means of Brillouin light scattering spectroscopy.

High-frequency magnetodielectric response in yttrium iron garnet at room temperature

NASA Astrophysics Data System (ADS)

Zhu, Jie; Liu, Yuan; Jia, Longfei; Zhang, Baoshan; Yang, Yi; Tang, Dongming

2018-05-01

Magnetic and dielectric properties of Yttrium Iron Garnet are measured over a frequency ranging from 0.5 GHz to 10 GHz with a magnetic field applied parallel to the propagation direction of the microwave. At the same time, the magnetodielectric phenomena are detected quantitatively. The maximum amplitude of the magnetodielectric coefficient is acquired at the ferromagnetic resonance frequency, and the value is up to 1.2% with the magnetic field of 1500 Oe applied. The phenomena have been explained by the Faraday's electromagnetic induction of the precession of the magnetic moments in the electromagnetic field at the ferromagnetic resonance frequency.

Hot Corrosion of Yttrium Stabilized Zirconia Coatings Deposited by Air Plasma Spray on a Nickel-Based Superalloy

NASA Astrophysics Data System (ADS)

Vallejo, N. Diaz; Sanchez, O.; Caicedo, J. C.; Aperador, W.; Zambrano, G.

In this research, the electrochemical impedance spectroscopy (EIS) and Tafel analysis were utilized to study the hot corrosion performance at 700∘C of air plasma-sprayed (APS) yttria-stabilized zirconia (YSZ) coatings with a NiCrAlY bond coat grown by high velocity oxygen fuel spraying (HVOF), deposited on an INCONEL 625 substrate, in contact with corrosive solids salts as vanadium pentoxide V2O5 and sodium sulfate Na2SO4. The EIS data were interpreted based on proposed equivalent electrical circuits using a suitable fitting procedure performed with Echem AnalystTM Software. Phase transformations and microstructural development were examined using X-ray diffraction (XRD), with Rietveld refinement for quantitative phase analysis, scanning electron microscopy (SEM) was used to determinate the coating morphology and corrosion products. The XRD analysis indicated that the reaction between sodium vanadate (NaVO3) and yttrium oxide (Y2O3) produces yttrium vanadate (YVO4) and leads to the transformation from tetragonal to monoclinic zirconia phase.

Surface characterization of low-temperature grown yttrium oxide

NASA Astrophysics Data System (ADS)

Krawczyk, Mirosław; Lisowski, Wojciech; Pisarek, Marcin; Nikiforow, Kostiantyn; Jablonski, Aleksander

2018-04-01

The step-by-step growth of yttrium oxide layer was controlled in situ using X-ray photoelectron spectroscopy (XPS). The O/Y atomic concentration (AC) ratio in the surface layer of finally oxidized Y substrate was found to be equal to 1.48. The as-grown yttrium oxide layers were then analyzed ex situ using combination of Auger electron spectroscopy (AES), elastic-peak electron spectroscopy (EPES) and scanning electron microscopy (SEM) in order to characterize their surface chemical composition, electron transport phenomena and surface morphology. Prior to EPES measurements, the Y oxide surface was pre-sputtered by 3 kV argon ions, and the resulting AES-derived composition was found to be Y0.383O0.465C0.152 (O/Y AC ratio of 1.21). The SEM images revealed different surface morphology of sample before and after Ar sputtering. The oxide precipitates were observed on the top of un-sputtered Y oxide layer, whereas the oxide growth at the Ar ion-sputtered surface proceeded along defects lines normal to the layer plane. The inelastic mean free path (IMFP) characterizing electron transport was evaluated as a function of energy in the range of 0.5-2 keV from the EPES method. Two reference materials (Ni and Au) were used in these measurements. Experimental IMFPs determined for the Y0.383O0.465C0.152 and Y2O3 surface compositions, λ, were uncorrected for surface excitations and approximated by the simple function λ = kEp at electron energies E between 500 eV and 2000 eV, where k and p were fitted parameters. These values were also compared with IMFPs resulting from the TPP-2 M predictive equation for both oxide compositions. The fitted functions were found to be reasonably consistent with the measured and predicted IMFPs. In both cases, the average value of the mean percentage deviation from the fits varied between 5% and 37%. The IMFPs measured for Y0.383O0.465C0.152 surface composition were found to be similar to the IMFPs for Y2O3.

A divalent rare earth oxide semiconductor: Yttrium monoxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaminaga, Kenichi; Sei, Ryosuke; Department of Chemistry, Tohoku University, Sendai 980-8578

Rare earth oxides are usually widegap insulators like Y{sub 2}O{sub 3} with closed shell trivalent rare earth ions. In this study, solid phase rock salt structure yttrium monoxide, YO, with unusual valence of Y{sup 2+} (4d{sup 1}) was synthesized in a form of epitaxial thin film by pulsed laser deposition method. YO has been recognized as gaseous phase in previous studies. In contrast with Y{sub 2}O{sub 3}, YO was dark-brown colored and narrow gap semiconductor. The tunable electrical conductivity ranging from 10{sup −1} to 10{sup 3} Ω{sup −1 }cm{sup −1} was attributed to the presence of oxygen vacancies serving as electron donor.more » Weak antilocalization behavior observed in magnetoresistance indicated significant role of spin-orbit coupling as a manifestation of 4d electron carrier.« less

Quantum storage of heralded polarization qubits in birefringent and anisotropically absorbing materials.

PubMed

Clausen, Christoph; Bussières, Félix; Afzelius, Mikael; Gisin, Nicolas

2012-05-11

Storage of quantum information encoded into heralded single photons is an essential constituent of long-distance quantum communication based on quantum repeaters and of optical quantum information processing. The storage of photonic polarization qubits is, however, difficult because many materials are birefringent and have polarization-dependent absorption. Here we present a simple scheme that eliminates these polarization effects, and we demonstrate it by storing heralded polarization qubits into a solid-state quantum memory. The quantum memory is implemented with a biaxial yttrium orthosilicate (Y2SiO5) crystal doped with rare-earth ions. Heralded single photons generated from a filtered spontaneous parametric down-conversion source are stored, and quantum state tomography of the retrieved polarization state reveals an average fidelity of 97.5±0.4%, which is significantly higher than what is achievable with a measure-and-prepare strategy.

Singular value decomposition approach to the yttrium occurrence in mineral maps of rare earth element ores using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Romppanen, Sari; Häkkänen, Heikki; Kaski, Saara

2017-08-01

Laser-induced breakdown spectroscopy (LIBS) has been used in analysis of rare earth element (REE) ores from the geological formation of Norra Kärr Alkaline Complex in southern Sweden. Yttrium has been detected in eudialyte (Na15 Ca6(Fe,Mn)3 Zr3Si(Si25O73)(O,OH,H2O)3 (OH,Cl)2) and catapleiite (Ca/Na2ZrSi3O9·2H2O). Singular value decomposition (SVD) has been employed in classification of the minerals in the rock samples and maps representing the mineralogy in the sampled area have been constructed. Based on the SVD classification the percentage of the yttrium-bearing ore minerals can be calculated even in fine-grained rock samples.

Neutron scattering study of yttrium iron garnet

NASA Astrophysics Data System (ADS)

Shamoto, Shin-ichi; Ito, Takashi U.; Onishi, Hiroaki; Yamauchi, Hiroki; Inamura, Yasuhiro; Matsuura, Masato; Akatsu, Mitsuhiro; Kodama, Katsuaki; Nakao, Akiko; Moyoshi, Taketo; Munakata, Koji; Ohhara, Takashi; Nakamura, Mitsutaka; Ohira-Kawamura, Seiko; Nemoto, Yuichi; Shibata, Kaoru

2018-02-01

The nuclear and magnetic structure and full magnon dispersions of yttrium iron garnet Y3Fe5O12 have been studied using neutron scattering. The refined nuclear structure is distorted to a trigonal space group of R 3 ¯ . The highest-energy dispersion extends up to 86 meV. The observed dispersions are reproduced by a simple model with three nearest-neighbor-exchange integrals between 16 a (octahedral) and 24 d (tetrahedral) sites, Ja a, Ja d, and Jd d, which are estimated to be 0.00 ±0.05 , -2.90 ±0.07 , and -0.35 ±0.08 meV, respectively. The lowest-energy dispersion below 14 meV exhibits a quadratic dispersion as expected from ferromagnetic magnons. The imaginary part of q -integrated dynamical spin susceptibility χ″(E ) exhibits a square-root energy dependence at low energies. The magnon density of state is estimated from χ″(E ) obtained on an absolute scale. The value is consistent with the single chirality mode for the magnon branch expected theoretically.

Crystallization of lanthanum and yttrium aluminosilicate glasses

NASA Astrophysics Data System (ADS)

Sadiki, Najim; Coutures, Jean Pierre; Fillet, Catherine; Dussossoy, Jean Luc

2006-01-01

The crystallization behaviour of aluminosilicate glasses of lanthanum (LAS) and yttrium (YAS) containing 2-8 mol% of Ln 2O 3 (Ln = La or Y), 12-30 mol% of Al 2O 3, and 64-80 mol% of SiO 2 has been studied by DTA, XRD and SEM-EDX analysis. X-ray diffraction results indicate the presence of the mullite phase and La 2Si 2O 7 in the monoclinic high-temperature G form (group space P2 1/c) for the LAS glasses, and mullite y-Y 2Si 2O 7 in the monoclinic structure (group space C2/m) and a small amount of β-Y 2Si 2O 7 in the orthorhombic structure (space group Pna2) for the YAS. For both cases, very little tridymite phase is observed. The results also show that the values of Tg for YAS are higher than those for LAS glasses. The crystallization of LAS glasses is more difficult than that of YAS. For all samples, we observed only one kind of mullite (Al/Si = 3.14).

Investigation of the imaging characteristics of the ALBIRA II small animal PET system for 18F, 68Ga and 64Cu.

PubMed

Attarwala, Ali Asgar; Karanja, Yvonne Wanjiku; Hardiansyah, Deni; Romanó, Chiara; Roscher, Mareike; Wängler, Björn; Glatting, Gerhard

2017-06-01

In this study the performance characteristics of the Albira II PET sub-system and the response of the system for the following radionuclides 18 F, 68 Ga and 64 Cu was analyzed. The Albira II tri-modal system (Bruker BioSpin MRI GmbH, Ettlingen, Germany) is a pre-clinical device for PET, SPECT and CT. The PET sub-system uses single continuous crystal detectors of lutetium yttrium orthosilicate (LYSO). The detector assembly consists of three rings of 8 detector modules. The transaxial field of view (FOV) has a diameter of 80mm and the axial FOV is 148mm. A NEMA NU-4 image quality phantom (Data Spectrum Corporation, Durham, USA) having five rods with diameters of 1, 2, 3, 4 and 5mm and a uniform central region was used. Measurements with 18 F, 68 Ga and 64 Cu were performed in list mode acquisition over 10h. Data were reconstructed using a maximum-likelihood expectation-maximization (MLEM) algorithm with iteration numbers between 5 and 50. System sensitivity, count rate linearity, convergence and recovery coefficients were analyzed. The sensitivities for the entire FOV (non-NEMA method) for 18 F, 68 Ga and 64 Cu were (3.78±0.05)%, (3.97±0.18)% and (3.79±0.37)%, respectively. The sensitivity based on the NEMA protocol using the 22 Na point source yielded (5.53±0.06)%. Dead-time corrected true counts were linear for activities ≤7MBq ( 18 F and 68 Ga) and ≤17MBq ( 64 Cu) in the phantom. The radial, tangential and axial full widths at half maximum (FWHMs) were 1.52, 1.47 and 1.48mm. Recovery coefficients for the uniform region with a total activity of 8MBq in the phantom were (0.97±0.05), (0.98±0.06), (0.98±0.06) for 18 F, 68 Ga and 64 Cu, respectively. The Albira II pre-clinical PET system has an adequate sensitivity range and the system linearity is suitable for the range of activities used for pre-clinical imaging. Overall, the system showed a favorable image quality for pre-clinical applications. Copyright © 2017. Published by Elsevier GmbH.

Thermal effects from modified endodontic laser tips used in the apical third of root canals with erbium-doped yttrium aluminium garnet and erbium, chromium-doped yttrium scandium gallium garnet lasers.

PubMed

George, Roy; Walsh, Laurence J

2010-04-01

To evaluate the temperature changes occurring on the apical third of root surfaces when erbium-doped yttrium aluminium garnet (Er:YAG) and erbium, chromium-doped yttrium scandium gallium garnet (Er,Cr:YSGG) laser energy was delivered with a tube etched, laterally emitting conical tip and a conventional bare design optical fiber tip. Thermal effects of root canal laser treatments on periodontal ligament cells and alveolar bone are of concern in terms of safety. A total of 64 single-rooted extracted teeth were prepared 1 mm short of the working length using rotary nickel-titanium Pro-Taper files to an apical size corresponding to a F5 Pro-Taper instrument. A thermocouple located 2 mm from the apex was used to record temperature changes arising from delivery of laser energy through laterally emitting conical tips or plain tips, using an Er:YAG or Er,Cr:YSGG laser. For the Er:YAG and Er,Cr:YSGG systems, conical fibers showed greater lateral emissions (452 + 69% and 443 + 64%) and corresponding lower forward emissions (48 + 5% and 49 + 5%) than conventional plain-fiber tips. All four combinations of laser system and fiber design elicited temperature increases less than 2.5 degrees C during lasing. The use of water irrigation attenuated completely the thermal effects of individual lasing cycles. Laterally emitting conical fiber tips can be used safely under defined conditions for intracanal irradiation without harmful thermal effects on the periodontal apparatus.

MCrAlY bond coat with enhanced yttrium

DOEpatents

Jablonski, Paul D.; Hawk, Jeffrey A.

2016-08-30

One or more embodiments relates to a method of producing an MCrAlY bond coat comprising an MCrAlY layer in contact with a Y--Al.sub.2O.sub.3 layer. The MCrAlY layer is comprised of a .gamma.-M solid solution, a .beta.-MAl intermetallic phase, and Y-type intermetallics. The Y--Al.sub.2O.sub.3 layer is comprised of Yttrium atoms coordinated with oxygen atoms comprising the Al.sub.2O.sub.3 lattice. The method comprises depositing an MCrAlY material on a substrate, applying an Y.sub.2O.sub.3 paste, and heating the substrate in a non-oxidizing atmosphere at a temperature between 400-1300.degree. C. for a time sufficient to generate the Y--Al.sub.2O.sub.3 layer. Both the MCrAlY layer and the Y--Al.sub.2O.sub.3 layer have a substantial absence of Y.sub.2O.sub.3, YAG, and YAP phases.

High-power 266 nm ultraviolet generation in yttrium aluminum borate.

PubMed

Liu, Qiang; Yan, Xingpeng; Gong, Mali; Liu, Hua; Zhang, Ge; Ye, Ning

2011-07-15

A yttrium aluminum borate [YAl(3)(BO(3))(4)] (YAB) crystal with UV cutoff wavelength of 165 nm is used as the nonlinear optical crystal for fourth harmonic generation. The fundamental frequency laser at 1064 nm from an Nd:YVO(4) master oscillator power amplifier laser was frequency doubled to 532 nm. Using the type I phase-matching YAB crystal, a 5.05 W average power 266 nm UV laser was obtained at the pulse repetition frequency of 65 kHz, corresponding to the conversion efficiency of 12.3% from 532 to 266 nm. The experimental results show great potential for the application of using YAB as a nonlinear optical crystal to get high-power fourth harmonic generation. © 2011 Optical Society of America

Improvement of light extraction of LYSO scintillator by using a combination of self-assembly of nanospheres and atomic layer deposition.

PubMed

Zhu, Zhichao; Liu, Bo; Zhang, Haifeng; Ren, Weina; Cheng, Chuanwei; Wu, Shuang; Gu, Mu; Chen, Hong

2015-03-23

The self-assembled monolayer periodic array of polystyrene spheres conformally coated with TiO₂ layer using atomic layer deposition is designed to obtain a further enhancement of light extraction for LYSO scintillator. The maximum enhancement is 149% for the sample with polystyrene spheres conformally coated with TiO₂ layer, while the enhancement is only 76% for the sample with only polystyrene spheres. Such further enhancement could be contributed from the additional modes forming by TiO₂ layer due to its high refractive index, which can be approved by the simulation of electric field distribution. The experimental results are agreement with the simulated results. Furthermore, the prepared structured layer exhibits an excellent combination with the surface of scintillator, which is in favor of the practical application. Therefore, it is safely concluded that the combination of self-assembly method and atomic layer deposition is a promising approach to obtain a significant enhancement of light extraction for a large area. This method can be extended to many other luminescent materials and devices.

Improving of the electrical and magnetic properties of BiFeO{sub 3} by doping with yttrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilić, Nikola I., E-mail: niksentije@gmail.com; Bobić, Jelena D.; Stojadinović, Bojan S.

2016-05-15

Bismuth ferrite is one of the most promising multiferroic materials, and the main barriers for exploiting all of its specific properties are difficulties in obtaining pure, high resistive material with nanosized grains. Doping of BiFeO{sub 3} with different transition metals and rare earth elements is often used way for overcoming these obstacles. Yttrium doped bismuth ferrite, Bi{sub 1−x}Y{sub x}FeO{sub 3} (x = 0; 0.01; 0.03; 0.05; 0.1), was prepared by auto-combustion method. X-ray diffraction patterns and Raman results showed that partial phase transition from rhombohedral to orthorhombic structure took place at around 10 mol% of Y. Effect of Y dopingmore » on microstructure was studied from SEM micrographies, showing the reduction of grain size in doped samples. Electrical measurements showed continuous improvement of resistivity with Y doping, whereas the values of saturation and remnant polarizations exhibit maximums at around 5 mol% of Y. Yttrium doping also enhanced magnetic properties, leading to weak ferromagnetism.« less

Titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition and a process for making the same

DOEpatents

Holcombe, Cressie E.; Dykes, Norman L.

1991-01-01

A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness.

Characterization of 1.2×1.2 mm2 silicon photomultipliers with Ce:LYSO, Ce:GAGG, and Pr:LuAG scintillation crystals as detector modules for positron emission tomography

NASA Astrophysics Data System (ADS)

Omidvari, N.; Sharma, R.; Ganka, T. R.; Schneider, F. R.; Paul, S.; Ziegler, S. I.

2017-04-01

The design of a positron emission tomography (PET) scanner is specially challenging since it should not compromise high spatial resolution, high sensitivity, high count-rate capability, and good energy and time resolution. The geometrical design of the system alongside the characteristics of the individual PET detector modules contributes to the overall performance of the scanner. The detector performance is mainly influenced by the characteristics of the photo-detector and the scintillation crystal. Although silicon photomultipliers (SiPMs) have already proven to be promising photo-detectors for PET, their performance is highly influenced by micro-cell structure and production technology. Therefore, five types of SiPMs produced by KETEK with an active area size of 1.2 × 1.2 mm2 were characterized in this study. The SiPMs differed in the production technology and had micro-cell sizes of 25, 50, 75, and 100 μm. Performance of the SiPMs was evaluated in terms of their breakdown voltage, temperature sensitivity, dark count rate, and correlated noise probability. Subsequently, energy resolution and coincidence time resolution (CTR) of the SiPMs were measured with five types of crystals, including two Ce:LYSO, two Ce:GAGG, and one Pr:LuAG. Two crystals with a geometry of 1.5 × 1.5 × 6 mm3 were available from each type. The best CTR achieved was ~ 240 ps, which was obtained with the Ce:LYSO crystals coupled to the 50 μm SiPM produced with the trench technology. The best energy resolution for the 511 keV photo-peak was ~ 11% and was obtained with the same SiPM coupled to the Ce:GAGG crystals.

Process for separation of zirconium-88, rubidium-83 and yttrium-88

DOEpatents

Heaton, Richard C.; Jamriska, Sr., David J.; Taylor, Wayne A.

1994-01-01

A process for selective separation of strontium-82 and strontium-85 from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, passing the first ion-containing solution through a first cationic resin whereby ions selected from the group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in the first ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the first resin, contacting the first resin with an acid solution capable of stripping adsorbed ions from the first cationic exchange resin whereby the adsorbed ions are removed from the first resin to form a second ion-containing solution, evaporating the second ion-containing solution for time sufficient to remove substantially all of the acid and water from the second ion-containing solution whereby a residue remains, dissolving the residue from the evaporated second-ion containing solution in a dilute acid to form a third ion-containing solution, said third ion-containing solution having an acid molarity adapted to permit said ions to be adsorbed by a cationic exchange resin, passing the third ion-containing solution through a second cationic resin whereby the ions are adsorbed by the second resin, contacting the second resin with a dilute sulfuric acid solution whereby the adsorbed ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, and zirconium are selectively removed from the second resin, and contacting the second resin with a dilute acid solution whereby the adsorbed strontium ions are selectively removed. Zirconium, rubidium, and yttrium radioisotopes can also be recovered with additional steps.

Evidence of dilute ferromagnetism in rare-earth doped yttrium aluminium garnet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farr, Warrick G.; Goryachev, Maxim; Le Floch, Jean-Michel

This work demonstrates strong coupling regime between an erbium ion spin ensemble and microwave hybrid cavity-whispering gallery modes in a yttrium aluminium garnet dielectric crystal. Coupling strengths of 220 MHz and mode quality factors in excess of 10{sup 6} are demonstrated. Moreover, the magnetic response of high-Q modes demonstrates behaviour which is unusual for paramagnetic systems. This behaviour includes hysteresis and memory effects. Such qualitative change of the system's magnetic field response is interpreted as a phase transition of rare earth ion impurities. This phenomenon is similar to the phenomenon of dilute ferromagnetism in semiconductors. The clear temperature dependence of themore » phenomenon is demonstrated.« less

[Intracoronary brachytherapy with strontium/yttrium-90. Initial experiences in Germany].

PubMed

Silber, S; von Rottkay, P; Gielow, A; Schneider, A; Bauer, A; Schöfer, H

1998-09-01

Restenosis after PTCA is still an unresolved problem and occurs in approximately 30% of our patients despite a stent implantation rate of up to 63%. Intracoronary brachytherapy has the potential to counteract the proliferative component of restenosis as well as to prevent shrinking of the coronary artery. Two years ago, we applied for the license to use the Novoste Beta-Cath system. This is the first report of its use in Germany. Attaining the license was complicated by the facts that this device did not yet have CE-certification (MPG section 17), that brachytherapy is not yet an approved method of treatment (StrSchV section 41), the report of the BfS and the approval by an accredited ethical committee. The application becomes even more complicated by the amount demanded by the LfU for insurance: 1 Million DM for each individual patient (AtDeckV section 15). The final local inspection needs to be performed by an expert from the LfAS (StrSchV section 76). Strontium-90 decays into Yttrium-90 with a half-life time of approximately 28 years. Yttrium-90, too, is a pure beta-emitter with a shorter half-life time of approximately 64 hours and a considerably higher electron energy of maximum 2.27 MeV. Yttrium-90 is the therapeutic agent. The radiation source of the Beta-Cath system consists of 12 single, separate cylinders (pellets, seeds) with a total length of 3 cm. The activity of the total train is approximately 1.3 to 1.5 GBq (35 to 40 mCi). For verification of the dose rate provided by the manufacturer, we performed a check using the GafChromic film. The test dose (exactly 2 mm from the center of the long axis of the activity train) was 150 Gy. We obtained the following results for the optical density: reference source: 0.29 +/- 0.01, source C: 0.318 +/- 0.013 and source D: 0.317 +/- 0.028. For a dose rate of e.g. 0.083 Gy/s, the radiation times are 169 s for a dose of 14 Gy (vessel diameter 2.7 to 3.35 mm) or 217 s for 18 Gy (vessel diameter 3.36 to 4.0 mm

Process for the separation and purification of yttrium-90 for medical applications

DOEpatents

Horwitz, P.E.; Dietz, M.L.

1994-11-29

An extraction chromatographic method for the preparation of [sup 90]Y of high chemical and radiochemical purity is disclosed. After an initial purification of a [sup 90]Sr stock solution and a suitable period of [sup 90]Y ingrowth, the solution is passed through a series of strontium-selective chromatographic columns, each of which lowers the [sup 90]Sr content of the mixture by a factor of about 10[sup 3]. The [sup 90]Y remaining is freed from any residual [sup 90]Sr, from its [sup 90]Zr daughter, and from any remaining impurities by passing the sample through a final column designed to selectively retain yttrium. 5 figures.

Process for the separation and purification of yttrium-90 for medical applications

DOEpatents

Horwitz, Philip E.; Dietz, Mark L.

1994-01-01

An extraction chromatographic method for the preparation of .sup.90 Y of high chemical and radiochemical purity is disclosed. After an initial purification of a .sup.90 Sr stock solution and a suitable period of .sup.90 Y ingrowth, the solution is passed through a series of strontium-selective chromatographic columns, each of which lowers the .sup.90 Sr content of the mixture by a factor of about 10.sup.3. The .sup.90 Y remaining is freed from any residual .sup.90 Sr, from its .sup.90 Zr daughter, and from any remaining impurities by passing the sample through a final column designed to selectively retain yttrium.

Reducing graphene device variability with yttrium sacrificial layers

NASA Astrophysics Data System (ADS)

Wang, Ning C.; Carrion, Enrique A.; Tung, Maryann C.; Pop, Eric

2017-05-01

Graphene technology has made great strides since the material was isolated more than a decade ago. However, despite improvements in growth quality and numerous "hero" devices, challenges of uniformity remain, restricting the large-scale development of graphene-based technologies. Here, we investigate and reduce the variability of graphene transistors by studying the effects of contact metals (with and without a Ti layer), resist, and yttrium (Y) sacrificial layers during the fabrication of hundreds of devices. We find that with optical photolithography, residual resist and process contamination are unavoidable, ultimately limiting the device performance and yield. However, using Y sacrificial layers to isolate the graphene from processing conditions improves the yield (from 73% to 97%), the average device performance (three-fold increase of mobility and 58% lower contact resistance), and the device-to-device variability (standard deviation of Dirac voltage reduced by 20%). In contrast to other sacrificial layer techniques, the removal of the Y sacrificial layer with dilute HCl does not harm surrounding materials, simplifying large-scale graphene fabrication.

Growth of rare-earth doped single crystal yttrium aluminum garnet fibers

NASA Astrophysics Data System (ADS)

Bera, Subhabrata; Nie, Craig D.; Harrington, James A.; Cheng, Long; Rand, Stephen C.; Li, Yuan; Johnson, Eric G.

2018-02-01

Rare-earth doped single crystal (SC) yttrium aluminum garnet (YAG) fibers have great potential as high-power laser gain media. SC fibers combine the superior material properties of crystals with the advantages of a fiber geometry. Improving processing techniques, growth of low-loss YAG SC fibers have been reported. A low-cost technique that allows for the growth of optical quality Ho:YAG single crystal (SC) fibers with different dopant concentrations have been developed and discussed. This technique is a low-cost sol-gel based method which offers greater flexibility in terms of dopant concentration. Self-segregation of Nd ions in YAG SC fibers have been observed. Such a phenomenon can be utilized to fabricate monolithic SC fibers with graded index.

The activities of acyl-CoA:1-acyl-lysophospholipid acyltransferase(s) in human platelets.

PubMed Central

Bakken, A M; Farstad, M

1992-01-01

The activities of acyl-CoA:1-acyl-lysophospholipid acyltransferases (EC 2.3.1.23) have been studied in human platelet lysates by using endogenously formed [14C]acyl-CoA from [14C]fatty acid, ATP and CoA in the presence of 1-acyl-lysophosphatidyl-choline (lysoPC), -ethanolamine (lysoPE), -serine (lysoPS) or -inositol (lysoPI). Linoleic acid as fatty acid substrate had the highest affinity to acyl-CoA:1-acyl-lysophospholipid acyltransferase with lysoPC as variable substrate, followed by eicosapentaenoic acid (EPA) and arachidonic acid (AA). The activity at optimal conditions was 7.4, 7.3 and 7.2 nmol/min per 10(9) platelets with lysoPC as substrate, with linoleic acid, AA and EPA respectively. EPA and AA were incorporated into all lyso-forms. Linoleic acid was also incorporated into lysoPE at a high rate, but less into lysoPS and lysoPI. DHA was incorporated into lysoPC and lysoPE, but only slightly into lysoPI and lysoPS. Whereas incorporation of all fatty acids tested was maximal for lysoPC and lysoPI at 200 and 80 microM respectively, maximal incorporation needed over 500 microM for lysoPE and lysoPS. The optimal concentration for [14C]fatty acid substrates was in the range 15-150 microM for all lysophospholipids. Competition experiments with equimolar concentrations of either lysoPC and lysoPI or lysoPE resulted in formation of [14C]PC almost as if lysoPI or lysoPE were not added to the assay medium. PMID:1471991

Bridgman growth of large-aperture yttrium calcium oxyborate crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Anhua, E-mail: wuanhua@mail.sic.ac.cn; Jiang, Linwen; Qian, Guoxing

2012-09-15

Highlights: ► YCOB is a novel non-linear optical crystal possessing good thermal, mechanical and nonlinear optical properties. ► Large size crystal growth is key technology question for YCOB crystal. ► YCOB crystals 3 in. in diameter were grown with modified vertical Bridgman method. ► It is a more effective growth method to obtain large size and high quality YCOB crystal. -- Abstract: Large-aperture yttrium calcium oxyborate YCa{sub 4}O(BO{sub 3}){sub 3} (YCOB) crystals with 3 in. in diameter were grown with modified vertical Bridgman method, and the large crystal plate (63 mm × 68 mm × 20 mm) was harvested formore » high-average power frequency conversion system. The crack, facet growth and spiral growth can be effectively controlled in the as-grown crystal, and Bridgman method displays more effective in obtain large size and high quality YCOB crystal plate than Czochralski technique.« less

Revising the magnetic structure and dynamics of Yttrium Iron Garnet

NASA Astrophysics Data System (ADS)

Princep, Andrew; Boothroyd, Andrew; Ewings, Russell; Ward, Simon; Dubs, Carsten

Yttrium iron garnet (YIG) is the `miracle material' of microwave magnetics. Since its synthesis by Geller and Gilleo in 1957, it is widely acknowledged to have contributed more to the understanding of electronic spin-wave and magnon dynamics than any other substance. Its astonishingly narrow excitation linewidth allows magnon propagation to be observed over centimetre distances, making it both a superior model system for the experimental study of fundamental aspects of microwave magnetic dynamics and an ideal platform for the development of microwave magnetic technologies. Our experiments on a large, pristine single crystal at the ISIS facility using both diffraction and time-of-flight spectroscopy have provided new results on both the magnetic structure and the excitation spectrum, which revise nearly 60 years of scientific research and will be essential insights for the fledgling scientific field of Magnonics. EPSRC, UK.

Excitation of the three principal spin waves in yttrium iron garnet using a wavelength-specific multi-element antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Wonbae; Jungfleisch, Matthias B.; Lim, Jinho

We report systematic measurements of the dispersion of long wavelength spin waves for the magnetic field along the three principal directions (supporting the forward volume, backward volume and Damon-Eshbach modes) of a 3.05 um thick yttrium iron garnet film on a lattice-matched (111) gadolinium gallium garnet substrate obtained using a lithographically patterned, multi-element, 50 um spatially-resonant, antenna.

Excitation of the three principal spin waves in yttrium iron garnet using a wavelength-specific multi-element antenna

DOE PAGES

Bang, Wonbae; Jungfleisch, Matthias B.; Lim, Jinho; ...

2017-12-22

We report systematic measurements of the dispersion of long wavelength spin waves for the magnetic field along the three principal directions (supporting the forward volume, backward volume and Damon-Eshbach modes) of a 3.05 um thick yttrium iron garnet film on a lattice-matched (111) gadolinium gallium garnet substrate obtained using a lithographically patterned, multi-element, 50 um spatially-resonant, antenna.

Reactivity of yttrium carboxylates toward alkylaluminum hydrides.

PubMed

Schädle, Christoph; Fischbach, Andreas; Herdtweck, Eberhardt; Törnroos, Karl W; Anwander, Reiner

2013-11-25

Yttrocene-carboxylate complex [Cp*2Y(OOCAr(Me))] (Cp*=C5Me5, Ar(Me) =C6H2Me3-2,4,6) was synthesized as a spectroscopically versatile model system for investigating the reactivity of alkylaluminum hydrides towards rare-earth-metal carboxylates. Equimolar reactions with bis-neosilylaluminum hydride and dimethylaluminum hydride gave adduct complexes of the general formula [Cp*2Y(μ-OOCAr(Me))(μ-H)AlR2] (R=CH2SiMe3, Me). The use of an excess of the respective aluminum hydride led to the formation of product mixtures, from which the yttrium-aluminum-hydride complex [{Cp*2Y(μ-H)AlMe2(μ-H)AlMe2(μ-CH3)}2] could be isolated, which features a 12-membered-ring structure. The adduct complexes [Cp*2Y(μ-OOCAr(Me))(μ-H)AlR2] display identical (1)J(Y,H) coupling constants of 24.5 Hz for the bridging hydrido ligands and similar (89)Y NMR shifts of δ=-88.1 ppm (R=CH2SiMe3) and δ=-86.3 ppm (R=Me) in the (89)Y DEPT45 NMR experiments. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-pressure investigations of yttrium(III) oxoarsenate(V): Crystal structure and luminescence properties of Eu3+-doped scheelite-type Y[AsO4] from xenotime-type precursors

NASA Astrophysics Data System (ADS)

Ledderboge, Florian; Nowak, Jan; Massonne, Hans-Joachim; Förg, Katharina; Höppe, Henning A.; Schleid, Thomas

2018-07-01

Colourless, water- and air-stable single crystals of yttrium(III) oxoarsenate(V) Y[AsO4] in the xenotime-type crystal structure were prepared by the reaction of yttrium sesquioxide (Y2O3) dissolved in aqueous nitric acid (13%) with a solution of arsenic(V) oxide hydrate (As2O5·3H2O) and subsequent neutralization with 1 M caustic soda. Y[AsO4] crystallizes tetragonally in the space group I41/amd with the lattice parameters a = 704.63(6) and c = 628.94(5) pm for Z = 4 and is isotypic to the minerals xenotime RE[PO4] (RE: mainly Y and Yb) and chernovite RE[AsO4] (RE: mainly Y and Ce). This xenotime-type yttrium compound was used as precursor in a high-pressure experiment (20 kbar) at 700 °C to create a new tetragonal modification of Y[AsO4]. It shows the scheelite-type structure (space group: I41/a) with the lattice parameters a = 498.23(4) and c = 1120.71(9) pm for Z = 4, named after the mineral scheelite (Ca[WO4]). Both tetragonal structures are characterized by only one crystallographically unique position for each of the Y3+, As5+ and O2- ions with distances of d(Y-O) = 232 and 241 pm (C.N. = 8) as well as d(As-O) = 169 pm (C.N. = 4) in the case of the scheelite-type structure. The xenotime-type compound shows an unexpected slight decrease in average bond lengths for the yttrium to oxygen (d(Y-O) = 230 and 241 pm, C.N. = 8) as well as for the arsenic to oxygen distances (d(As-O) = 168 pm, C.N. = 4), accompanied by a drastic density increase from Dx = 4.85 (xenotime type) to Dx = 5.44 g • cm-3 (scheelite type). Luminescence spectroscopic measurements of the Eu3+-doped Y[AsO4] samples, obtained in experiments at similar conditions as for the pure compounds, show a bright, reddish lighting for the scheelite type, which does not occur for the xenotime type of yttrium(III) oxoarsenate(V).

Optimized conditions for chelation of yttrium-90-DOTA immunoconjugates.

PubMed

Kukis, D L; DeNardo, S J; DeNardo, G L; O'Donnell, R T; Meares, C F

1998-12-01

Radioimmunotherapy (RIT) with 90Y-labeled immunoconjugates has shown promise in clinical trials. The macrocyclic chelating agent 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetic acid (DOTA) binds 90Y with extraordinary stability, minimizing the toxicity of 90Y-DOTA immunoconjugates arising from loss of 90Y to bone. However, reported 90Y-DOTA immunoconjugate product yields have been typically only < or =50%. Improved yields are needed for RIT with 90Y-DOTA immunoconjugates to be practical. (S) 2-[p-(bromoacetamido)benzyl]-DOTA (BAD) was conjugated to the monoclonal antibody Lym-1 via 2-iminothiolane (2IT). The immunoconjugate product, 2IT-BAD-Lym-1, was labeled in excess yttrium in various buffers over a range of concentrations and pH. Kinetic studies were performed in selected buffers to estimate radiolabeling reaction times under prospective radiopharmacy labeling conditions. The effect of temperature on reaction kinetics was examined. Optimal radiolabeling conditions were identified and used in eight radiolabeling experiments with 2IT-BAD-Lym-1 and a second immunoconjugate, DOTA-peptide-chimeric L6, with 248-492 MBq (6.7-13.3 mCi) of 90Y. Ammonium acetate buffer (0.5 M) was associated with the highest uptake of yttrium. On the basis of kinetic data, the time required to chelate 94% of 90Y (four half-times) under prospective radiopharmacy labeling conditions in 0.5 M ammonium acetate was 17-148 min at pH 6.5, but it was only 1-10 min at pH 7.5. Raising the reaction temperature from 25 degrees C to 37 degrees C markedly increased the chelation rate. Optimal radiolabeling conditions were identified as: 30-min reaction time, 0.5 M ammonium acetate buffer, pH 7-7.5 and 37 degrees C. In eight labeling experiments under optimal conditions, a mean product yield (+/- s.d.) of 91%+/-8% was achieved, comparable to iodination yields. The specific activity of final products was 74-130 MBq (2.0-3.5 mCi) of 90Y per mg of monoclonal antibody. The immunoreactivity of 90Y

Alkylation of pyridines at their 4-positions with styrenes plus yttrium reagent or benzyl Grignard reagents.

PubMed

Mizumori, Tomoya; Hata, Takeshi; Urabe, Hirokazu

2015-01-02

A new regioselective alkylation of pyridines at their 4-position was achieved with styrenes in the presence of yttrium trichloride, BuLi, and diisobutylaluminium hydride (DIBAL-H) in THF. Alternatively, similar products were more simply prepared from pyridines and benzyl Grignard reagents. These reactions are not only a useful preparation of 4-substituted pyridines but are also complementary to other relevant reactions usually giving 2-substituted pyridines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A process for the separation and purification of yttrium-90 for medical applications

DOEpatents

Horwitz, P.E.; Dietz, M.L.

1993-01-01

An extraction chromatographic method for the preparation of {sup 90}Y of high chemical and radiochemical purity is disclosed. After an initial purification of a {sup 90}Sr stock solution and a suitable period of {sup 90}Y ingrowth, the solution is passed through a series of strontium-selective chromatographic columns, each of which lowers the {sup 90}Sr content of the mixture by a factor of about 10{sup 3}. The {sup 90}Y remaining is freed from any residual {sup 90}Sr, from its {sup 90}Zr daughter, and from any remaining impurities by passing the sample through a final column designed to selectively retain yttrium.

Pseudopotential plane-wave calculation of the structural properties of yttrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Y.; Chou, M.Y.

1991-11-01

The structural properties of hexagonal-close-packed yttrium are studied by using the plane-wave basis within the pseudopotential method and local-density-functional approximation. By employing a soft'' pseudopotential proposed by Troullier and Martins, satisfactory convergence is achieved with a plane-wave energy cutoff of 30--40 Ry for this early-transition-metal element. The overall results for the structural properties are in good agreement with experiment. It is found that the charge overlap between core and valence electrons has a substantial effect on the accuracy of the calculated structural properties. Two different calculations are performed with and without the outer-core 4{ital p} orbital included as a valencemore » state. In addition, as found in some other local-density calculations, the uncertainty in the results due to different exchange-correlation energy functionals may not be negligible in transition metals.« less

Effect of aluminum and yttrium doping on zinc sulphide nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Swati, E-mail: sharma.swati1507@gmail.com; Kashyap, Jyoti; Kapoor, A.

2016-05-06

In this work, pristine and doped Zinc Sulphide (ZnS) nanoparticles have been synthesized via chemical co-precipitation method. ZnS nanoparticles have been doped with Aluminium (Al) and Yttrium (Y) with doping concentration of 5wt% each. The structural and optical properties of the as prepared nanoparticles have been studied using X-Ray diffraction (XRD) technique and Photoluminescence spectroscopy. Average grain size of 2-3nm is observed through the XRD analysis. Effect of doping on stress, strain and lattice constant of the nanoparticles has also been analyzed. Photoluminescence spectra of the as prepared nanoparticles is enhanced due to Al doping and quenched due to Ymore » doping. EDAX studies confirm the relative doping percentage to be 3.47 % and 3.94% by wt. for Al and Y doped nanoparticles respectively. Morphology of the nanoparticles studied using TEM and SEM indicates uniform distribution of spherical nanoparticles.« less

Excitation of the three principal spin waves in yttrium iron garnet using a wavelength-specific multi-element antenna

NASA Astrophysics Data System (ADS)

Bang, Wonbae; Jungfleisch, Matthias B.; Lim, Jinho; Trossman, Jonathan; Tsai, C. C.; Hoffmann, Axel; Ketterson, John B.

2018-05-01

We report systematic measurements of the dispersion of long wavelength spin waves for the magnetic field along the three principal directions (supporting the forward volume, backward volume and Damon-Eshbach modes) of a 3.05 μm thick yttrium iron garnet film on a lattice-matched (111) gadolinium gallium garnet substrate obtained using a lithographically patterned, multi-element, 50 μm spatially-resonant, antenna.

Power scaling of diode-pumped neodymium yttrium aluminum borate laser

NASA Technical Reports Server (NTRS)

Hemmati, Hamid

1991-01-01

Preliminary results are presented of the efficient diode-pumped operation of a neodymium yttrium aluminum borate (NYAB) laser at 531.5 nm using two 1-W diode-laser arrays for the pump. With 1380 mW of CW power incident on the crystal, as much as 51 mW of 532.5-nm laser radiation was obtained with the unoptimized cavity. The corresponding optical-to-optical conversion efficiency was 3.7 percent. A plot of the output 531.5 nm vs incident 807 nm pump power is shown. The crystal output power was critically dependent on the rotational and translational adjustment of the NYAB crystal inside the cavity. It is suggested that a crystal cut at the exact phase matching angle, placed in a cavity with proper optimal reflection and transmission mirror coatings, and pumped at proper wavelength can result in higher output power. Thus, the NYAB output power approaches that of a CW intracavity frequency doubled Nd:YAG laser.

Phase Diagram for Magnon Condensate in Yttrium Iron Garnet Film

PubMed Central

Li, Fuxiang; Saslow, Wayne M.; Pokrovsky, Valery L.

2013-01-01

Recently, magnons, which are quasiparticles describing the collective motion of spins, were found to undergo Bose-Einstein condensation (BEC) at room temperature in films of Yttrium Iron Garnet (YIG). Unlike other quasiparticle BEC systems, this system has a spectrum with two degenerate minima, which makes it possible for the system to have two condensates in momentum space. Recent Brillouin Light Scattering studies for a microwave-pumped YIG film of thickness d = 5 μm and field H = 1 kOe find a low-contrast interference pattern at the characteristic wavevector Q of the magnon energy minimum. In this report, we show that this modulation pattern can be quantitatively explained as due to unequal but coherent Bose-Einstein condensation of magnons into the two energy minima. Our theory predicts a transition from a high-contrast symmetric state to a low-contrast non-symmetric state on varying the d and H, and a new type of collective oscillation. PMID:23455849

Synthesis, crystal structures and luminescence properties of the Eu 3+-doped yttrium oxotellurates(IV) Y 2Te 4O 11 and Y 2Te 5O 13

NASA Astrophysics Data System (ADS)

Höss, Patrick; Osvet, Andres; Meister, Frank; Batentschuk, Miroslaw; Winnacker, Albrecht; Schleid, Thomas

2008-10-01

Y 2Te 4O 11:Eu 3+ and Y 2Te 5O 13:Eu 3+ single crystals in sub-millimeter scale were synthesized from the binary oxides (Y 2O 3, Eu 2O 3 and TeO 2) using CsCl as fluxing agent. Crystallographic structures of the undoped yttrium oxotellurates(IV) Y 2Te 4O 11 and Y 2Te 5O 13 have been determined and refined from single-crystal X-ray diffraction data. In Y 2Te 4O 11, a layered structure is present where the reticulated sheets consisting of edge-sharing [YO 8] 13- polyhedra are interconnected by the oxotellurate(IV) units, whereas in Y 2Te 5O 13 only double chains of condensed yttrium-oxygen polyhedra with coordination numbers of 7 and 8 are left, now linked in two crystallographic directions by the oxotellurate(IV) entities. The Eu 3+ luminescence spectra and the decay time from different energy levels of the doped compounds were investigated and all detected emission levels were identified. Luminescence properties of the Eu 3+ cations have been interpreted in consideration of the now accessible detailed crystallographic data of the yttrium compounds, providing the possibility to examine the influence of the local symmetry of the oxygen coordination spheres.

Magnetophotonic crystals based on yttrium-iron-garnet infiltrated opals: Magnetization-induced second-harmonic generation

NASA Astrophysics Data System (ADS)

Murzina, T. V.; Kim, E. M.; Kapra, R. V.; Moshnina, I. V.; Aktsipetrov, O. A.; Kurdyukov, D. A.; Kaplan, S. F.; Golubev, V. G.; Bader, M. A.; Marowsky, G.

2006-01-01

Three-dimensional magnetophotonic crystals (MPCs) based on artificial opals infiltrated by yttrium iron garnet (YIG) are fabricated and their structural, optical, and nonlinear optical properties are studied. The formation of the crystalline YIG inside the opal matrix is checked by x-ray analysis. Two templates are used for the infiltration by YIG: bare opals and those covered by a thin platinum film. Optical second-harmonic generation (SHG) technique is used to study the magnetization-induced nonlinear-optical properties of the composed MPCs. A high nonlinear magneto-optical Kerr effect in the SHG intensity is observed at the edge of the photonic band gap of the MPCs.

Synthesis and characterization of amorphous yttrium oxide layers by metal organic chemical solution deposition

NASA Astrophysics Data System (ADS)

Martynova, I.; Tsymbarenko, D.; Kamenev, A.; Kuzmina, N.; Kaul, A.

2014-02-01

The Solution Deposition Planarization method was successfully used for smoothing Ni-alloy tapes with initial surface roughness of 26.7 nm (on 40×40 μm2 area) and 12.6 nm (on 5×5 μm2 area). New precursor solutions were prepared from yttrium acetate and diethylenetriamine or ethylenediamine in MeOH and i-PrOH-alcohols with different viscosities. Using those solutions yttria films with the residual roughness Sa=0.4 nm (on 5×5 μm2 area) and Sa=7.6 nm (on 40×40 μm2 area) were deposited on the Ni-alloy tapes.

Growth of high quality yttrium iron garnet films using standard pulsed laser deposition technique

NASA Astrophysics Data System (ADS)

Zaki, Aliaa M.; Blythe, Harry J.; Heald, Steve M.; Fox, A. Mark; Gehring, Gillian A.

2018-05-01

Thin films with properties comparable to bulk single crystals were grown by pulsed laser deposition using a substrate temperature of only 500 °C. This was achieved by a careful choice of both the oxygen pressure in the deposition chamber and the temperature of the air anneal. The best films were grown on gadolinium gallium garnet substrates but we also report data for films grown on the diamagnetic substrate yttrium aluminium garnet. The films were analysed using X-ray diffraction, near edge X-ray absorption and magnetometry. Our best films had a magnetisation of 143 emu/cm3 and a coercive field of ∼1 Oe.

Formation and accumulation of radiation-induced defects and radiolysis products in modified lithium orthosilicate pebbles with additions of titanium dioxide

NASA Astrophysics Data System (ADS)

Zarins, Arturs; Valtenbergs, Oskars; Kizane, Gunta; Supe, Arnis; Knitter, Regina; Kolb, Matthias H. H.; Leys, Oliver; Baumane, Larisa; Conka, Davis

2016-03-01

Lithium orthosilicate (Li4SiO4) pebbles with 2.5 wt.% excess of silicon dioxide (SiO2) are the European Union's designated reference tritium breeding ceramics for the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM). However, the latest irradiation experiments showed that the reference Li4SiO4 pebbles may crack and form fragments under operation conditions as expected in the HCPB TBM. Therefore, it has been suggested to change the chemical composition of the reference Li4SiO4 pebbles and to add titanium dioxide (TiO2), to obtain lithium metatitanate (Li2TiO3) as a second phase. The aim of this research was to investigate the formation and accumulation of radiation-induced defects (RD) and radiolysis products (RP) in the modified Li4SiO4 pebbles with different contents of TiO2 for the first time, in order to estimate and compare radiation stability. The reference and the modified Li4SiO4 pebbles were irradiated with accelerated electrons (E = 5 MeV) up to 5000 MGy absorbed dose at 300-990 K in a dry argon atmosphere. By using electron spin resonance (ESR) spectroscopy it was determined that in the modified Li4SiO4 pebbles, several paramagnetic RD and RP are formed and accumulated, like, E' centres (SiO33-/TiO33-), HC2 centres (SiO43-/TiO3-) etc. On the basis of the obtained results, it is concluded that the modified Li4SiO4 pebbles with TiO2 additions have comparable radiation stability with the reference pebbles.

High-resolution electronic spectra of yttrium oxide (YO): The D2Σ+-X2Σ+ transition.

PubMed

Zhang, Deping; Zhang, Qiang; Zhu, Boxing; Gu, Jingwang; Suo, Bingbing; Chen, Yang; Zhao, Dongfeng

2017-03-21

The D 2 Σ + -X 2 Σ + electronic absorption spectrum of the astrophysically relevant yttrium oxide (YO) molecule has been recorded for the first time in the 400-440 nm region using laser induced fluorescence. YO molecules are produced by corona discharge of oxygen between the tips of two yttrium needles in a supersonic jet expansion. An unambiguous spectroscopic identification of the D 2 Σ + -X 2 Σ + transition becomes possible from a combined analysis of the moderate-resolution laser excitation spectrum and dispersed fluorescence spectrum. We have also performed multi-state complete active space second order perturbation theory calculations on the first six doublets of YO, and the results support our assignment of the D 2 Σ + state. Accurate spectroscopic constants for D 2 Σ + ν' = 0 and 1 levels have been determined from a rotational analysis of the high resolution spectra that are recorded with a resolution of ∼0.018 cm -1 . Severe perturbations are observed in the experimental spectra and are considered to originate from interactions with at least one nearby 2/4 Π electronic state, e.g., the undetected C 2 Π state. We have also measured the radiative lifetimes of B 2 Σ + ν' = 0, and D 2 Σ + ν' = 0 and 1 states, based on which the B 2 Σ + -X 2 Σ + (0, 0) and D 2 Σ + -X 2 Σ + (0/1, 0) band oscillator strengths have been determined.

High-resolution electronic spectra of yttrium oxide (YO): The D2Σ+-X2Σ+ transition

NASA Astrophysics Data System (ADS)

Zhang, Deping; Zhang, Qiang; Zhu, Boxing; Gu, Jingwang; Suo, Bingbing; Chen, Yang; Zhao, Dongfeng

2017-03-01

The D2Σ+ -X2Σ+ electronic absorption spectrum of the astrophysically relevant yttrium oxide (YO) molecule has been recorded for the first time in the 400-440 nm region using laser induced fluorescence. YO molecules are produced by corona discharge of oxygen between the tips of two yttrium needles in a supersonic jet expansion. An unambiguous spectroscopic identification of the D2Σ+ -X2Σ+ transition becomes possible from a combined analysis of the moderate-resolution laser excitation spectrum and dispersed fluorescence spectrum. We have also performed multi-state complete active space second order perturbation theory calculations on the first six doublets of YO, and the results support our assignment of the D2Σ+ state. Accurate spectroscopic constants for D2Σ+ ν ' = 0 and 1 levels have been determined from a rotational analysis of the high resolution spectra that are recorded with a resolution of ˜0.018 cm-1. Severe perturbations are observed in the experimental spectra and are considered to originate from interactions with at least one nearby 2/4Π electronic state, e.g., the undetected C2Π state. We have also measured the radiative lifetimes of B2 Σ+ ν ' = 0, and D2 Σ+ ν ' = 0 and 1 states, based on which the B2Σ+ -X2Σ+ (0, 0) and D2Σ+ -X2Σ+ (0/1, 0) band oscillator strengths have been determined.

Hyperpolarized 89Y NMR spectroscopic detection of yttrium ion and DOTA macrocyclic ligand complexation: pH dependence and Y-DOTA intermediates

NASA Astrophysics Data System (ADS)

Ferguson, Sarah; Kiswandhi, Andhika; Niedbalski, Peter; Parish, Christopher; Kovacs, Zoltan; Lumata, Lloyd

Dissolution dynamic nuclear polarization (DNP) is a rapidly emerging physics technique used to enhance the signal strength in nuclear magnetic resonance (NMR) and imaging (MRI) experiments for nuclear spins such as yttrium-89 by >10,000-fold. One of the most common and stable MRI contrast agents used in the clinic is Gd-DOTA. In this work, we have investigated the binding of the yttrium and DOTA ligand as a model for complexation of Gd ion and DOTA ligand. The macrocyclic ligand DOTA is special because its complexation with lanthanide ions such as Gd3+ or Y3+ is highly pH dependent. Using this physics technology, we have tracked the complexation kinetics of hyperpolarized Y-triflate and DOTA ligand in real-time and detected the Y-DOTA intermediates. Different kinds of buffers were used (lactate, acetate, citrate, oxalate) and the pseudo-first order complexation kinetic calculations will be discussed. The authors would like to acknowledge the support by US Dept of Defense Award No. W81XWH-14-1-0048 and Robert A. Welch Foundation Grant No. AT-1877.

Characterization of blue sensitive 3 × 3 mm2 SiPMs and their use in PET

NASA Astrophysics Data System (ADS)

Schneider, F. R.; Ganka, T. R.; Şeker, G.; Engelmann, E.; Renker, D.; Paul, S.; Hansch, W.; Ziegler, S. I.

2014-07-01

Three types of SiPMs (Silicon Photomultiplier) with an active area of 3 × 3 mm2 manufactured by KETEK with cell sizes of 50 μm (PM3350), 60 μm (PM3360) and 75 μm (PM3375) have been investigated. All devices have optical trenches in between the cells to suppress direct crosstalk. Their breakdown voltage at room temperature is about 23 V and the gain at an overvoltage Uover = 3.4 V is > 6·106. The temperature variation of the breakdown voltage is < 16 mV/K and the gain coefficient with temperature is < 1% for overvoltages Uover > 1.7 V. The photodetection efficiency (PDE) at 420 nm and Uover = 3.4 V is 51% for PM3350, 55% for PM3360 and 58% for PM3375. At Uover = 3.4 V, the dark count rates are < 470 kHz/mm2 at 20°C and the afterpulse probability is < 9% at -20°C. Single photon timing of 230 ps FWHM for PM3350, 320 ps for PM3360 and 375 ps for PM3375 have been achieved. To test their performance in PET (Positron Emission Tomography), energy spectra of 22Na with LYSO (Lutetium Yttrium Oxyorthosilicate, Lu1.8Y.2SiO5:Ce) and GAGG (Gadolinium Aluminum Gallium Garnet, Gd3(Ga,Al)5O15:Ce) scintillators with a size of 2 × 2×6 mm3 have been acquired. The saturation corrected energy resolution (FHWM) at 511 keV was with LYSO 12.3% for PM3350, 13.4% for PM3360, 12.4% for PM3375 and with GAGG 10.8% for PM3350. Coincidence timing (FWHM) at Uover = 3.4 V was with LYSO 174 ps for PM3350, 178 ps for PM3360, 157 ps for PM3375 and with GAGG 430 ps for PM3350.

A divalent rare earth oxide semiconductor: Yttrium monoxide

NASA Astrophysics Data System (ADS)

Kaminaga, Kenichi; Sei, Ryosuke; Hayashi, Kouichi; Happo, Naohisa; Tajiri, Hiroo; Oka, Daichi; Fukumura, Tomoteru; Hasegawa, Tetsuya

Rare earth sesquioxides like Y2O3 are known as widegap insulators with the highly stable closed shell trivalent rare earth ions. On the other hand, rare earth monoxides such as YO have been recognized as gaseous phase, and only EuO and YbO were thermodynamically stable solid-phase rock salt monoxides. In this study, solid-phase rock salt yttrium monoxide, YO, was synthesized in a form of epitaxial thin film by pulsed laser deposition method. YO possesses unusual valence of Y2+ ([Kr] 4d1) . In contrast with Y2O3, YO was narrow gap semiconductor with dark-brown color. The electrical conductivity was tunable from 10-1 to 103 Ω-1 cm-1 by introducing oxygen vacancies as electron donor. Weak antilocalization behavior was observed indicating significant spin-orbit coupling owing to 4 d electron carrier. The absorption spectral shape implies the Mott-Hubbard insulator character of YO. Rare earth monoixdes will be new platform of functional oxides. This work was supported by JST-CREST, the Japan Society for the Promotion of Science (JSPS) with Grant-in-Aid for Scientific Research on Innovative Areas (Nos. 26105002 and 26105006), and Nanotechnology Platform (Project No.12024046) of MEXT, Japan.

Detection of high energy muons with sub-20 ps timing resolution using L(Y)SO crystals and SiPM readout

NASA Astrophysics Data System (ADS)

Benaglia, A.; Gundacker, S.; Lecoq, P.; Lucchini, M. T.; Para, A.; Pauwels, K.; Auffray, E.

2016-09-01

Precise timing capability will be a key aspect of particle detectors at future high energy colliders, as the time information can help in the reconstruction of physics events at the high collision rate expected there. Other than being used in detectors for PET, fast scintillating crystals coupled to compact Silicon Photomultipliers (SiPMs) constitute a versatile system that can be exploited to realize an ad-hoc timing device to be hosted in a larger high energy physics detector. In this paper, we present the timing performance of LYSO:Ce and LSO:Ce codoped 0.4% Ca crystals coupled to SiPMs, as measured with 150 GeV muons at the CERN SPS H2 extraction line. Small crystals, with lengths ranging from 5 mm up to 30 mm and transverse size of 2 × 2mm2 or 3 × 3mm2 , were exposed to a 150 GeV muon beam. SiPMs from two different companies (Hamamatsu and FBK) were used to detect the light produced in the crystals. The best coincidence time resolution value of (14.5 ± 0.5) ps , corresponding to a single-detector time resolution of about 10 ps, is demonstrated for 5 mm long LSO:Ce,Ca crystals coupled to FBK SiPMs, when time walk corrections are applied.

Current Role of Selective Internal Irradiation With Yttrium-90 Microspheres in the Management of Hepatocellular Carcinoma: A Systematic Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lau, Wan Yee, E-mail: josephlau@cuhk.edu.hk; Lai, Eric C.H.; Leung, Thomas W.T.

2011-10-01

Purpose: This article reviews the role of selective internal irradiation (SIR) with yttrium-90 ({sup 90}Y) microspheres for hepatocellular carcinoma (HCC). Methods and Materials: Studies were identified by searching Medline and PubMed databases for articles from 1990 to 2009 using the keywords 'selective internal irradiation,' 'hepatocellular carcinoma,' 'therapeutic embolization,' and 'yttrium-90.' Results: {sup 90}Y microspheres are a safe and well-tolerated therapy for unresectable HCC (median survival range, 7 -21.6 months). The evidence was limited to cohort studies and comparative studies with historical control. {sup 90}Y microspheres have been reported to downstage unresectable HCC to allow for salvage treatments with curative intent,more » act as a bridging therapy before liver transplantation, and treat HCC with curative intent for patients who are not surgical candidates because of comorbidities. Conclusions: {sup 90}Y microsphere is recommended as an option of palliative therapy for large or multifocal HCC without major portal vein invasion or extrahepatic spread. It can also be used for recurrent unresectable HCC, as a bridging therapy before liver transplantation, as a tumor downstaging treatment, and as a curative treatment for patients with associated comorbidities who are not candidates for surgery.« less

Flux-gate magnetic field sensor based on yttrium iron garnet films for magnetocardiography investigations

NASA Astrophysics Data System (ADS)

Vetoshko, P. M.; Gusev, N. A.; Chepurnova, D. A.; Samoilova, E. V.; Syvorotka, I. I.; Syvorotka, I. M.; Zvezdin, A. K.; Korotaeva, A. A.; Belotelov, V. I.

2016-08-01

A new type of f lux-gate vector magnetometer based on epitaxial yttrium iron garnet films has been developed and constructed for magnetocardiography (MCG) investigations. The magnetic field sensor can operate at room temperature and measure MCG signals at a distance of about 1 mm from the thoracic cage. The high sensitivity of the sensor, better than 100 fT/Hz1/2, is demonstrated by the results of MCG measurements on rats. The main MCG pattern details and R-peak on a level of 10 pT are observed without temporal averaging, which allows heart rate anomalies to be studied. The proposed magnetic sensors can be effectively used in MCG investigations.

Spin wave propagation in perpendicularly magnetized nm-thick yttrium iron garnet films

NASA Astrophysics Data System (ADS)

Chen, Jilei; Heimbach, Florian; Liu, Tao; Yu, Haiming; Liu, Chuanpu; Chang, Houchen; Stückler, Tobias; Hu, Junfeng; Zeng, Lang; Zhang, Youguang; Liao, Zhimin; Yu, Dapeng; Zhao, Weisheng; Wu, Mingzhong

2018-03-01

Magnonics offers a new way for information transport that uses spin waves (SWs) and is free of charge currents. Unlike Damon-Eshbach SWs, the magneto-static forward volume SWs offer the reciprocity configuration suitable for SW logic devices with low power consumption. Here, we study forward volume SW propagation in yttrium iron garnet (YIG) thin films with an ultra-low damping constant α = 8 ×10-5 . We design different integrated microwave antenna with different k-vector excitation distributions on YIG thin films. Using a vector network analyzer, we measured SW transmission with the films magnetized in perpendicular orientation. Based on the experimental results, we extract the group velocity as well as the dispersion relation of SWs and directly compare the power efficiency of SW propagation in YIG using coplanar waveguide and micro stripline for SW excitation and detection.

HIGH-RESOLUTION L(Y)SO DETECTORS USING PMT-QUADRANT-SHARING FOR HUMAN & ANIMAL PET CAMERAS

PubMed Central

Ramirez, Rocio A.; Liu, Shitao; Liu, Jiguo; Zhang, Yuxuan; Kim, Soonseok; Baghaei, Hossain; Li, Hongdi; Wang, Yu; Wong, Wai-Hoi

2009-01-01

We developed high resolution L(Y)SO detectors for human and animal PET applications using Photomultiplier-quadrant-sharing (PQS) technology. The crystal sizes were 1.27 × 1.27 × 10 mm3 for the animal PQS-blocks and 3.25 × 3.25 × 20 mm3 for human ones. Polymer mirror film patterns (PMR) were placed between crystals as reflector. The blocks were assembled together using optical grease and wrapped by Teflon tape. The blocks were coupled to regular round PMT’s of 19/51 mm in PQS configuration. List-mode data of Ga-68 source (511 KeV) were acquired with our high yield pileup-event recovery (HYPER) electronics and data acquisition software. The high voltage bias was 1100V. Crystal decoding maps and individual crystal energy resolutions were extracted from the data. To investigate the potential imaging resolution of the PET cameras with these blocks, we used GATE (Geant4 Application for Tomographic Emission) simulation package. GATE is a GEANT4 based software toolkit for realistic simulation of PET and SPECT systems. The packing fractions of these blocks were found to be 95.6% and 98.2%. From the decoding maps, all 196 and 225 crystals were clearly identified. The average energy resolutions were 14.0% and 15.6%. For small animal PET systems, the detector ring diameter was 16.5 cm with an axial field of view (AFOV) of 11.8 cm. The simulation data suggests that a reconstructed radial (tangential) spatial resolution of 1.24 (1.25) mm near the center is potentially achievable. For the wholebody human PET systems, the detector ring diameter was 86 cm. The simulation data suggests that a reconstructed radial (tangential) spatial resolution of 3.09(3.38) mm near the center is potentially achievable. From this study we can conclude that PQS design could achieve high spatial resolutions and excellent energy resolutions on human and animal PET systems with substantially lower production costs and inexpensive readout devices. PMID:19946463

Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout

NASA Astrophysics Data System (ADS)

Bläckberg, L.; El Fakhri, G.; Sabet, H.

2017-11-01

A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to  >42%, and for rough interfaces  >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically

Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout.

PubMed

Bläckberg, L; El Fakhri, G; Sabet, H

2017-10-19

A tightly focused pulsed laser beam can locally modify the crystal structure inside the bulk of a scintillator. The result is incorporation of so-called optical barriers with a refractive index different from that of the crystal bulk, that can be used to redirect the scintillation light and control the light spread in the detector. We here systematically study the scintillation light transport in detectors fabricated using the laser induced optical barrier technique, and objectively compare their potential performance characteristics with those of the two mainstream detector types: monolithic and mechanically pixelated arrays. Among countless optical barrier patterns, we explore barriers arranged in a pixel-like pattern extending all-the-way or half-way through a 20 mm thick LYSO:Ce crystal. We analyze the performance of the detectors coupled to MPPC arrays, in terms of light response functions, flood maps, line profiles, and light collection efficiency. Our results show that laser-processed detectors with both barrier patterns constitute a new detector category with a behavior between that of the two standard detector types. Results show that when the barrier-crystal interface is smooth, no DOI information can be obtained regardless of barrier refractive index (RI). However, with a rough barrier-crystal interface we can extract multiple levels of DOI. Lower barrier RI results in larger light confinement, leading to better transverse resolution. Furthermore we see that the laser-processed crystals have the potential to increase the light collection efficiency, which could lead to improved energy resolution and potentially better timing resolution due to higher signals. For a laser-processed detector with smooth barrier-crystal interfaces the light collection efficiency is simulated to  >42%, and for rough interfaces  >73%. The corresponding numbers for a monolithic crystal is 39% with polished surfaces, and 71% with rough surfaces, and for a mechanically

Morphology and magnetic characterisation of aluminium substituted yttrium-iron garnet nanoparticles prepared using sol gel technique.

PubMed

Yahya, Noorhana; Al Habashi, Ramadan Masoud; Koziol, Krzysztof; Borkowski, Rafal Dunin; Akhtar, Majid Niaz; Kashif, Muhammad; Hashim, Mansor

2011-03-01

Aluminum substituted yttrium iron garnet nano particles with compositional variation of Y(3.0-x) A1(x)Fe5O12, where x = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 were prepared using sol gel technique. The X-ray diffraction results showed that the best garnet phase appeared when the sintering temperature was 800 degrees C. Nano-crystalline particles with high purity and sizes ranging from 20 to 100 nm were obtained. It was found that the aluminum substitution had resulted in a sharp fall of the d-spacing when x = 2, which we speculated is due to the preference of the aluminum atoms to the smaller tetrahedron and octahedron sites instead of the much larger dodecahedron site. High resolution transmission electron microscope (HRTEM) and electron diffraction (ED) patterns showed single crystal nanoparticles were obtained from this method. The magnetic measurement gave moderate values of initial permeability; the highest value of 5.3 was shown by sample Y3Fe5O12 at more than 100 MHz which was attributed to the morphology of the microstructure which appeared to be homogeneous. This had resulted in an easy movement of domain walls. The substitution of aluminum for yttrium is speculated to cause a cubic to rhombodedral structural change and had weakened the super-exchange interactions thus a fall of real permeability was observed. This might have created a strain in the sub-lattices and had subsequently caused a shift of resonance frequencies to more than 1.8 GHz when x > 0.5.

Spectrum and energy levels of six-times ionized yttrium (Y VII)

NASA Astrophysics Data System (ADS)

Reader, Joseph

2018-03-01

The spectrum of six-times ionized yttrium, Y VII, was photographed with a sliding-spark discharge on 10.7 m normal- and grazing-incidence spectrographs. The region of observation was 157-824 Å. The observations extend the known configurations 4s24p3, 4s4p4, 4p5, 4s24p25s, 4s24p26s to the nearly complete 4s24p24d configuration. Our results for 4s24p24d significantly revise results of Rahimullah et al (1978 Phys. Scr. 18 96); Ateqad et al (1984 J. Phys. B: At. Mol. Phys. 17 4617). A total of 168 lines and 56 energy levels are now known for this ion. The observed configurations were interpreted with Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels. Transition probabilities for all classified lines were calculated with the fitted parameters.

Efficient eye-safe neodymium doped composite yttrium gallium garnet crystal laser.

PubMed

Yu, Haohai; Wang, Shuxian; Han, Shuo; Wu, Kui; Su, Liangbi; Zhang, Huaijin; Wang, Zhengping; Xu, Jun; Wang, Jiyang

2014-03-15

We report a laser-diode pumped continuous-wave (cw) and passively Q-switched eye-safe laser at about 1.42 μm with the neodymium-doped yttrium gallium garnet (Nd:YGG) crystal for the first time to our knowledge. The composite Nd:YGG crystal was developed originally. A systematic comparison of laser performance between the homogeneously doped and composite Nd:YGG crystal was made, which showed that the composite Nd:YGG manifested less thermally induced effects. Cw output power of 2.06 W was obtained with the slope efficiency of 20.7%. With a V:YAG as a saturable absorber, the passive Q-switching at 1.42 μm was gotten with the pulse width, pulse energy, and peak power of 34 ns, 46.7 μJ, and 1.4 kW, respectively. The present work should provide a potential candidate for the generation of eye-safe lasers.

Finite temperature magnon spectra in yttrium iron garnet from a mean field approach in a tight-binding model

NASA Astrophysics Data System (ADS)

Shen, Ka

2018-04-01

We study magnon spectra at finite temperature in yttrium iron garnet using a tight-binding model with nearest-neighbor exchange interaction. The spin reduction due to thermal magnon excitation is taken into account via the mean field approximation to the local spin and is found to be different at two sets of iron atoms. The resulting temperature dependence of the spin wave gap shows good agreement with experiment. We find that only two magnon modes are relevant to the ferromagnetic resonance.

Wetting of single crystal mullite by borosilicate and yttrium-aluminosilicate glasses and wetting phenomena of steels containing aluminum and titanium

NASA Astrophysics Data System (ADS)

Eldred, Benjamin Todd

This dissertation consists of two major sections. The first section concerns the wetting of single crystal mullite by borosilicate and yttrium-aluminosilicate glasses. The borosilicate glass showed poor wetting and interacted only moderately with the substrate. The yttrium-aluminosilicate glass interacted strongly with mullite and showed very good wetting. Balanced chemical equations between each glass and mullite were derived from EDS data. Wetting was found to be dependent on the crystallographic orientation of the substrate, in agreement with previous studies of the surface energy of mullite. The second section concerns the wetting phenomena of steels containing aluminum and titanium. A modified sessile drop technique was used to investigate the wetting of steels containing aluminum and/or titanium as a function of furnace atmosphere. It was found that the steel chemistry and furnace atmosphere had little effect on wetting except in the case of a particular ultra-low carbon steel containing both aluminum and titanium. This steel was found to show significantly lower contact angles than any other steel tested when it was in an atmosphere of pure hydrogen. As nitrogen was added to the atmosphere, the contact angle increased monotonically and irreversibly. The interaction between aluminum, titanium, and nitrogen is explained in terms of first-order interaction coefficients available in thermodynamic literature.

A microwave-mediated saponification of galactosylceramide and galactosylceramide I3-sulfate and identification of their lyso-compounds by delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

PubMed

Taketomi, T; Hara, A; Uemura, K; Kurahashi, H; Sugiyama, E

1996-07-16

Small amounts of galactosylceramide (cerebroside) and galactosylceramide I3-sulfate (sulfatide) obtained from porcine spinal cord and equine kidney were deacylated by a rapid method of microwave-mediated saponification to prepare their lyso-compounds. Mass spectra of their protonated or deprotonated molecular ion peaks were detected by recently developed new technology of a delayed extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometer with reflector detector in positive or negative ion mode. Long chain bases of lysocerebroside and lysosulfatide were different between porcine spinal cord and equine kidney, but similar to each other in the same organ, suggesting their common synthetic pathway. It is noted that the new rapid method can be similarly applied to the deacylation of both cerebroside and sulfatide in contrast to our classical method which was able to be applied to cerebroside, but not to sulfatide.

Chemoembolic Hepatopulmonary Shunt Reduction to Allow Safe Yttrium-90 Radioembolization Lobectomy of Hepatocellular Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaba, Ron C., E-mail: rgaba@uic.edu; VanMiddlesworth, Kyle A.

2012-12-15

Yttrium-90 ({sup 90}Y) radioembolization represents an emerging transcatheter treatment option for the management of hepatocellular carcinoma (HCC). Elevation of the hepatopulmonary shunt fraction risks nontarget radiation to the lungs and may limit the use of {sup 90}Y therapy in patients with locally advanced disease with vascular invasion, who often demonstrate increased shunting. We present two cases in which patients with HCC and portal vein invasion resulting in elevated hepatopulmonary shunt fractions underwent chemoembolic shunt closure to allow safe {sup 90}Y radioembolization. Both patients demonstrated excellent tumor response and patient survival. On this basis, we propose a role for chemoembolic reductionmore » of the lung shunt fraction before {sup 90}Y radioembolization in patients with extensive tumor-related hepatopulmonary shunting.« less

Synthesis of dense yttrium-stabilised hafnia pellets for nuclear applications by spark plasma sintering

NASA Astrophysics Data System (ADS)

Tyrpekl, Vaclav; Holzhäuser, Michael; Hein, Herwin; Vigier, Jean-Francois; Somers, Joseph; Svora, Petr

2014-11-01

Dense yttrium-stabilised hafnia pellets (91.35 wt.% HfO2 and 8.65 wt.% Y2O3) were prepared by spark plasma sintering consolidation of micro-beads synthesised by the "external gelation" sol-gel technique. This technique allows a preparation of HfO2-Y2O3 beads with homogenous yttria-hafnia solid solution. A sintering time of 5 min at 1600 °C was sufficient to produce high density pellets (over 90% of the theoretical density) with significant reproducibility. The pellets have been machined in a lathe to the correct dimensions for use as neutron absorbers in an experimental test irradiation in the High Flux Reactor (HFR) in Petten, Holland, in order to investigate the safety of americium based nuclear fuels.

Yttrium enrichment and improved magnetic properties in partially melted Y-Ba-Cu-O materials

NASA Technical Reports Server (NTRS)

Alterescu, Sidney; Hojaji, Hamid; Barkatt, Aaron; Michael, Karen A.; Hu, Shouxiang

1990-01-01

The yttrium-rich compositions in the Y-Ba-Cu-O system were mapped out in a systematic manner to quantify their magnetic properties and to correlate them with the microstructure and phase composition as determined by scanning electron microscopy and X-ray diffraction analysis. It is found that the microstructure of Y-Ba-Cu-O compositions is a sensitive function of both their composition and processing conditions. Measurements of magnetic susceptibility and maximum (low-field) and remanent magnetization for the system Y:Ba:Cu = x:2:3 show highest values for x = 2. The corresponding structures involve numerous small crystals of Y2BaCuO5 (211) embedded in highly ordered assemblages of continous YBa2Cu3O(7-y) (123) layers.

Structure and luminescence spectra of lutetium and yttrium borates synthesized from ammonium nitrate melt

NASA Astrophysics Data System (ADS)

Klassen, Nikolay V.; Shmurak, Semion Z.; Shmyt'ko, Ivan M.; Strukova, Galina K.; Derenzo, Stephen E.; Weber, Marvin J.

2005-01-01

Lutetium and yttrium borates doped with europium, terbium, gadolinium, etc. have been synthesized by dissolving initial oxides and nitrates in ammonium nitrate melt and thermal decomposition of the solvent. Annealings in the range of 500-1100°C modified the dimensions of the grains from 2 to 3 nm to more than 100 nm. Significant dependence of the structure of lutetium borate on slight doping with rare earth ions has been found: terbium makes high-temperature vaterite phase preferential at room temperature, whereas europium stabilizes low-temperature calcite phase. Influence of the structure of the borates on the pattern of the luminescence spectra of europium dopant was observed. Possibilities for manufacturing of scintillating lutetium borate ceramics by means of this method of synthesis are discussed.

Baicalin promotes the bacteriostatic activity of lysozyme on S. aureus in mammary glands and neutrophilic granulocytes in mice

PubMed Central

Zhang, Zecai; Shen, Peng; Yang, Zhengtao; Zhang, Naisheng

2017-01-01

Staphylococcus aureus causes mastitis as a result of community-acquired or nosocomial infections. Lysozyme (LYSO) is an enzyme that is upregulated in many organisms during the innate immune response against infection by bacterial pathogens. Baicalin is a bioactive flavonoid that can bind to enzymes, often to potentiate their effect. Here we tested the effects of baicalin on the activity of LYSO using the S. aureus mastitis mouse model and neutrophilic granulocyte model of S. aureus infection. In our experiments, S. aureus counts decreased with increasing baicalin concentration. Furthermore, qPCR and western blot analyses showed that LYSO expression was unaffected by baicalin, while fluorescence quenching and UV fluorescence spectral analyses showed that baicalin binds to LYSO. To test whether this binding increased LYSO activity, we assessed LYSO-induced bacteriostasis in the presence of baicalin. Our results showed that LYSO-induced S. aureus bacteriostasis increased with increasing concentrations of baicalin, and that baicalin binding to LYSO synergistically increased the antibacterial activity of LYSO. These results demonstrate that baicalin enhances LYSO-induced bacteriostasis during the innate immune response to S. aureus. They suggest baicalin is a potentially useful therapeutic agent for the treatment of bacterial infections. PMID:28184027

Sources and distribution of yttrium and rare earth elements in surface sediments from Tagus estuary, Portugal.

PubMed

Brito, Pedro; Prego, Ricardo; Mil-Homens, Mário; Caçador, Isabel; Caetano, Miguel

2018-04-15

The distribution and sources of yttrium and rare-earth elements (YREE) in surface sediments were studied on 78 samples collected in the Tagus estuary (SW Portugal, SW Europe). Yttrium and total REE contents ranged from 2.4 to 32mg·kg -1 and 18 to 210mg·kg -1 , respectively, and exhibited significant correlations with sediment grain-size, Al, Fe, Mg and Mn, suggesting a preferential association to fine-grained material (e.g. aluminosilicates but also Al hydroxides and Fe oxyhydroxides). The PAAS (Post-Archean Australian Shale) normalized patterns display three distinct YREE fractionation pattern groups along the Tagus estuary: a first group, characterized by medium to coarse-grained material, a depleted and almost flat PAAS-normalized pattern, with a positive anomaly of Eu, representing one of the lithogenic components; a second group, characterized mainly by fine-grained sediment, with higher shale-normalized ratios and an enrichment of LREE relative to HREE, associated with waste water treatment plant (WWTP) outfalls, located in the northern margin; and, a third group, of fine-grained material, marked by a significant enrichment of Y, a depletion of Ce and an enrichment of HREE over LREE, located near an inactive chemical-industrial complex (e.g. pyrite roast plant, chemical and phosphorous fertilizer industries), in the southern margin. The data allow the quantification of the YREE contents and its spatial distribution in the surface sediments of the Tagus estuary, identifying the main potential sources and confirming the use of rare earth elements as tracers of anthropogenic activities in highly hydrodynamic estuaries. Copyright © 2017 Elsevier B.V. All rights reserved.

High-Pressure Synthesis and Characterization of the Ammonium Yttrium Borate (NH4)YB8O14.

PubMed

Schmitt, Martin K; Podewitz, Maren; Liedl, Klaus R; Huppertz, Hubert

2017-11-20

The first high-pressure yttrium borate (NH 4 )YB 8 O 14 was synthesized at 12.8 GPa/1300 °C using a Walker-type multianvil module. The compound crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a = 17.6375(9), b = 10.7160(5), and c = 4.2191(2) Å. (NH 4 )YB 8 O 14 constitutes a novel structure type but exhibits similarities to the crystal structure of β-BaB 4 O 7 . X-ray single-crystal and powder diffraction, EDX, vibrational spectroscopy as well as quantum chemical calculations were used to characterize (NH 4 )YB 8 O 14 .

Simultaneous Profiling of Lysoglycerophospholipids in Rice (Oryza sativa L.) Using Direct Infusion-Tandem Mass Spectrometry with Multiple Reaction Monitoring.

PubMed

Lim, Dong Kyu; Mo, Changyeun; Long, Nguyen Phuoc; Kim, Giyoung; Kwon, Sung Won

2017-03-29

White rice is the final product after the hull and bran layers have been removed during the milling process. Although lysoglycerophospholipids (lysoGPLs) only occupy a small proportion in white rice, they are essential for evaluating rice authenticity and quality. In this study, we developed a high-throughput and targeted lipidomics approach that involved direct infusion-tandem mass spectrometry with multiple reaction monitoring to simultaneously profile lysoGPLs in white rice. The method is capable of characterizing 17 lysoGPLs within 1 min. In addition, unsupervised and supervised analyses exhibited a considerably large diversity of lysoGPL concentrations in white rice from different origins. In particular, a classification model was built using identified lysoGPLs that can differentiate white rice from Korea, China, and Japan. Among the discriminatory lysoGPLs, for the lysoPE(16:0) and lysoPE(18:2) compositions, there were relatively small within-group variations, and they were considerably different among the three countries. In conclusion, our proposed method provides a rapid, high-throughput, and comprehensive format for profiling lysoGPLs in rice samples.

Electrical properties of epitaxial yttrium iron garnet ultrathin films at high temperatures

NASA Astrophysics Data System (ADS)

Thiery, N.; Naletov, V. V.; Vila, L.; Marty, A.; Brenac, A.; Jacquot, J.-F.; de Loubens, G.; Viret, M.; Anane, A.; Cros, V.; Ben Youssef, J.; Beaulieu, N.; Demidov, V. E.; Divinskiy, B.; Demokritov, S. O.; Klein, O.

2018-02-01

We report a study on the electrical properties of 19-nm-thick yttrium iron garnet (YIG) films grown by liquid phase epitaxy on gadolinium gallium garnet single crystal. The electrical conductivity and Hall coefficient are measured in the high-temperature range [300,400] K using a Van der Pauw four-point probe technique. We find that the electrical resistivity decreases exponentially with increasing temperature following an activated behavior corresponding to a band gap of Eg≈2 eV. It drops to values about 5 ×103Ω cm at T =400 K, thus indicating that epitaxial YIG ultrathin films behave as large gap semiconductors. We also infer the Hall mobility, which is found to be positive (p type) at 5 cm2V-1sec-1 and almost independent of temperature. We discuss the consequence for nonlocal spin transport experiments performed on YIG at room temperature and demonstrate the existence of electrical offset voltages to be disentangled from pure spin effects.

Complete eradication of hepatic metastasis from colorectal cancer by Yttrium-90 SIRT

PubMed Central

Garrean, Sean; Muhs, Amanda; Bui, James T; Blend, Michael J; Owens, Charles; Helton, William S; Espat, N Joseph

2007-01-01

Yttrium-90 (Y-90) radioembolization, also known as selective internal radiation therapy (SIRT), is a regional hepatic therapy used in the treatment of unresectable colorectal cancer (CRC) liver metastases. In SIRT, Y-90 impregnated microspheres are injected into the VASCULAR SUPPLY of hepatic tumor, leading to selective irradiation and necrosis of tumor TISSUE. While several studies demonstrate improved local control and survival with SIRT, the specific indications for this therapy have yet to be defined. Typically, SIRT is given in combination with chemotherapy as multimodal treatment for unresectable hepatic CRC. However, it HAS ALSO FOUND INCREASING USE as a salvage therapy in chemo-refractory patients. Herein, the authors describe their experience with SIRT as “stand alone” therapy in a surgically-prohibitive, chemotherapy naive patient with hepatic CRC metastasis. The results suggest that Y-90 SIRT may have potential applications beyond its usual role as a palliative or salvage therapy for unresectable hepatic CRC. PMID:17589957

Raman and Infrared Spectroscopy of Yttrium Aluminum Borate Glasses and Glass-ceramics

NASA Technical Reports Server (NTRS)

Bradley, J.; Brooks, M.; Crenshaw, T.; Morris, A.; Chattopadhyay, K.; Morgan, S.

1998-01-01

Raman spectra of glasses and glass-ceramics in the Y2O3-Al2O3-B2O3 system are reported. Glasses with B2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400 C for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 800 C were performed in order to induce nucleation and crystallization. It was found that Na2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl3(BO3)4.

Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET.

PubMed

Gundacker, Stefan; Auffray, Etiennette; Pauwels, Kristof; Lecoq, Paul

2016-04-07

The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time (τd) and the number of photons detected (n'), i.e. CTR proportional variant √τd/n'. However, it is still an open question to what extent the scintillation rise time (τr) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, prompt photons (Cherenkov) can be observed at the beginning of the scintillation event. Furthermore a significantly lower rise time value is observed when codoping with calcium. To quantitatively investigate the influence of the rise time to the time resolution we measured the CTR with the same L(Y)SO samples and compared the values to Monte Carlo simulations. Using the measured relative light yields, rise- and decay times of the scintillators we are able to quantitatively understand the measured CTRs in our simulations. Although the rise time is important to fully explain the CTR variation for the different samples tested we determined its influence on the CTR to be in the order of a few percent only. This result is surprising because, if only photonstatistics of the scintillation process is considered, the CTR would be proportional to the square root of the rise time. The unexpected small rise time influence on the CTR can be explained by the convolution of the scintillation rate with the single photon time

Measurement of intrinsic rise times for various L(Y)SO and LuAG scintillators with a general study of prompt photons to achieve 10 ps in TOF-PET

NASA Astrophysics Data System (ADS)

Gundacker, Stefan; Auffray, Etiennette; Pauwels, Kristof; Lecoq, Paul

2016-04-01

The coincidence time resolution (CTR) of scintillator based detectors commonly used in positron emission tomography is well known to be dependent on the scintillation decay time ({τd} ) and the number of photons detected ({{n}\\prime} ), i.e. CTR\\propto \\sqrt{{τd}/{{n}\\prime}} . However, it is still an open question to what extent the scintillation rise time ({τr} ) and other fast or prompt photons, e.g. Cherenkov photons, at the beginning of the scintillation process influence the CTR. This paper presents measurements of the scintillation emission rate for different LSO type crystals, i.e. LSO:Ce, LYSO:Ce, LSO:Ce codoped Ca and LGSO:Ce. For the various LSO-type samples measured we find an average value of 70 ps for the scintillation rise time, although some crystals like LSO:Ce codoped Ca seem to have a much faster rise time in the order of 20 ps. Additional measurements for LuAG:Ce and LuAG:Pr show a rise time of 535 ps and 251 ps, respectively. For these crystals, prompt photons (Cherenkov) can be observed at the beginning of the scintillation event. Furthermore a significantly lower rise time value is observed when codoping with calcium. To quantitatively investigate the influence of the rise time to the time resolution we measured the CTR with the same L(Y)SO samples and compared the values to Monte Carlo simulations. Using the measured relative light yields, rise- and decay times of the scintillators we are able to quantitatively understand the measured CTRs in our simulations. Although the rise time is important to fully explain the CTR variation for the different samples tested we determined its influence on the CTR to be in the order of a few percent only. This result is surprising because, if only photonstatistics of the scintillation process is considered, the CTR would be proportional to the square root of the rise time. The unexpected small rise time influence on the CTR can be explained by the convolution of the scintillation rate with the

Lithotripsy of gallstones by means of a quality-switched giant-pulse neodymium:yttrium-aluminum-garnet laser. Basic in vitro studies using a highly flexible fiber system.

PubMed

Hochberger, J; Gruber, E; Wirtz, P; Dürr, U; Kolb, A; Zanger, U; Hahn, E G; Ell, C

1991-11-01

The quality-switched neodymium:yttrium-aluminum-garnet laser represents a new instrument for athermal fragmentation of gallstones by transformation of optical energy into mechanical energy in the form of shock waves via local plasma formation. A highly flexible 300-micron fiber transmission system was used in basic investigations to determine the influence of varying pulse repetition rates (5-30 Hz) and pulse energies (15 and 20 mJ) on shock wave intensity and stone fragmentation in vitro for 105 biliary calculi of known size and chemical composition. After performance of 1200 shock wave pressure measurements using polyvinylidenefluoride hydrophones, stone fragmentation was analyzed by determination of fragment removal rates (volume of fragments removed per fragmentation time), ablation rates (mean volume removed per laser pulse), and median fragment sizes for each laser setting. With the quality-switched neodymium:yttrium-aluminum-garnet laser system, all concrements could be reliably disintegrated into small fragments (median diameter, 0.7-1.7 mm). Compared with pure cholesterol stones, a significantly higher fragment removal rate was achieved in cholesterol stones containing 30% calcium phosphate (P = 0.039), in cholesterol stones containing 20% pigment (P = 0.015), and in pure pigment stones (P = 0.007). Fragment removal rates, local shock wave pressures, and median grain sizes were significantly higher at a pulse energy of 20 mJ than with 15 mJ. Shock wave pressures showed a distinct dependence on pulse repetition rates at 20 mJ, yet not at 15 mJ. Because there is no evident hazard of thermal damage to tissue using the quality-switched neodymium:yttrium-aluminum-garnet laser, it appears to be a promising device for nonsurgical biliary stone therapy.

Correlation between evolution of inclusions and pitting corrosion in 304 stainless steel with yttrium addition.

PubMed

Shi, Weining; Yang, Shufeng; Li, Jingshe

2018-03-19

Effects of the evolution of inclusions on the pitting corrosion resistance of 304 stainless steel with different contents of the rare-earth element yttrium (Y) were studied using thermodynamic calculations, accelerated immersion tests, and electrochemical measurements. The experimental results showed that regular Y 2 O 3 inclusions demonstrated the best pitting resistance, followed in sequence by (Al,Mn)O inclusions, the composite inclusions, and irregular Y 2 O 3 inclusions. The pitting resistance first decreased, then increased, and then decreased again with increasing Y content, because sulfide inclusions were easily generated when the Y content was low and YN inclusions were easily generated at higher Y contents. The best pitting corrosion resistance was obtained for 304 stainless steel with addition of 0.019% Y.

Effectiveness of radiation synovectomy with Yttrium-90 and Samarium-153 particulate hydroxyapatite in rheumatoid arthritis patients with knee synovitis: a controlled, randomized, double-blinded trial.

PubMed

Dos Santos, Marla Francisca; Furtado, Rita Nely Vilar; Konai, Monique Sayuri; Castiglioni, Mario Luiz Vieira; Marchetti, Renata Rosa; Silva, Constancia Pagano Gonçalves; Natour, Jamil

2011-01-01

The aim of the present study was to investigate the long-term effectiveness of and tolerance to Yttrium-90 and Samarium-153-particulate hydroxyapatite radiation synovectomy in patients with rheumatoid arthritis (RA) and chronic knee synovitis. Eight-four patients (90 knees) with chronic knee synovitis and RA (according to the American College of Rheumatology criteria) participated in a controlled, double-blinded trial. Patients were randomized to receive an intra-articular injection with either 5 mCi Yttrium-90 plus 40 mg of triamcinolone hexacetonide (Y/TH Group), 15 mCi Samarium-153 hydroxyapatite plus 40 mg of triamcinolone hexacetonide (Sm/TH Group), or 40 mg triamcinolone hexacetonide alone (Control Group). Blinded examination at baseline, 1, 4, 12, 32, and 48 weeks post-intervention included a visual analog scale for joint pain and swelling, morning stiffness, range of motion, knee circumference, Likert scale, percentage of improvement, Stanford Health Assessment Questionnaire, Lequesne index, use of non-steroidal anti-inflammatory drugs and corticosteroids, events and adverse effects, calls to the physician, and hospital visits. There were three withdrawals prior to the injections. Regarding the pain, there was a significantly better response in the Y/TH Group versus the Sm/TH Group at T1 (p = 0.025) and versus TH alone at T48 (p = 0.026). The Sm/TH group had more adverse effects (p = 0.042), but these were mild and transitory. For the pain parameter alone, Yttrium-90 radiosynovectomy associated to TH proved superior to Samarium-153 hydroxyapatite radiosynovectomy associated to TH at T1 and to synovectomy with TH at T48. No other statistically significant inter-group differences were detected.

Negative permittivity and permeability spectra of Cu/yttrium iron garnet hybrid granular composite materials in the microwave frequency range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsutaoka, Takanori, E-mail: tsutaok@hiroshima-u.ac.jp; Fukuyama, Koki; Kinoshita, Hideaki

2013-12-23

The relative complex permittivity and permeability spectra of the coagulated copper and yttrium iron garnet (Cu/YIG) hybrid granular composite materials have been studied in the microwave range. The insulator to metal transition was observed at the percolation threshold of Cu particle content (φ{sub Cu} = 16.0 vol. %) in the electrical conductivity. In the percolation threshold, the low frequency plasmonic state caused by the metallic Cu particle networks was observed. The percolated Cu/YIG granular composites show simultaneous negative permittivity and permeability spectra under external magnetic fields.

Neutrophils Regulate Tissue Neutrophilia in Inflammation via the Oxidant-modified Lipid Lysophosphatidylserine*

PubMed Central

Frasch, S. Courtney; Fernandez-Boyanapalli, Ruby F.; Berry, Karin A. Zemski; Murphy, Robert C.; Leslie, Christina C.; Nick, Jerry A.; Henson, Peter M.; Bratton, Donna L.

2013-01-01

Resolution of neutrophilia characteristic of acute inflammation requires cessation of neutrophil recruitment and removal of tissue neutrophils. Based on in vitro studies, a role in these events was hypothesized for oxidant-generated lysophosphatidylserine (lyso-PS) on recruited neutrophils signaling via the G2A receptor on macrophages. Peritoneal exudate neutrophils harvested from wild type (WT) mice had 5-fold more lyso-PS (lyso-PShigh) than those of gp91phox−/− (lyso-PSlow) mice. Ex vivo engulfment of lyso-PShigh neutrophils (95% viable) by WT peritoneal macrophages was quantitatively similar to UV-irradiated apoptotic blood neutrophils, although the signaling pathway for the former was uniquely dependent on macrophage G2A. In contrast, lyso-PSlow neutrophils were poorly engulfed unless presented with exogenous lyso-PS. Enhanced clearance of lyso-PShigh neutrophils was also seen in vivo following their adoptive transfer into inflamed peritonea of WT but not G2A−/− mice, further supporting a requirement for signaling via G2A. To investigate downstream effects of lyso-PS/G2A signaling, antibody blockade of G2A in WT mice reduced macrophage CD206 expression and efferocytosis during peritonitis. Conversely, adoptive transfer of lyso-PShigh neutrophils early in inflammation in gp91phox−/− mice led to accelerated development of efferocytichigh and CD206high macrophages. This macrophage reprogramming was associated with suppressed production of pro-inflammatory mediators and reduced neutrophilia. These effects were not seen if G2A was blocked or lyso-PSlow neutrophils were transferred. Taken together, the results demonstrate that oxidant-generated lyso-PS made by viable tissue neutrophils is an endogenous anti-inflammatory mediator working in vivo to orchestrate the “early” and rapid clearance of recruited neutrophils as well as the reprogramming of “resolving” macrophages. PMID:23293064

Liver Resection for Colorectal Hepatic Metastases after Systemic Chemotherapy and Selective Internal Radiation Therapy with Yttrium-90 Microspheres: A Systematic Review.

PubMed

Baltatzis, Minas; Siriwardena, Ajith K

2018-06-08

Selective internal radiation therapy (SIRT) using yttrium-90 resin microspheres has been used together with systemic chemotherapy to treat patients with unresectable liver metastases. This study undertook the first systematic pooled assessment of the case profile, treatment and outcome in patients with initially inoperable colorectal hepatic metastases undergoing resection after systemic chemotherapy and SIRT. A systematic review of the literature was performed using Medline and Embase for publications between January 1998 and August 2017. Keywords and MESH headings "SIRT", "Yttrium-99 radio embolization" and "liver metastases" were used. Reports on patients undergoing liver resection after SIRT for colorectal liver metastases were included. Case reports, reviews and papers without original data were excluded. The study protocol was registered with PROSPERO, (registration number: CRD42017072374). The study population comprised of 120 patients undergoing liver resection after chemotherapy and SIRT. The conversion rate to hepatectomy in previously unresectable patients was 13.6% (109 of 802). All studies report a single application of SIRT. The interval from SIRT to surgery ranged from 39 days to 9 months. Overall, there were 4 (3.3%) deaths after hepatectomy in patients treated by chemotherapy and SIRT. This large pooled report of patients undergoing hepatectomy for colorectal liver metastases after chemotherapy and SIRT shows that 13.6% of patients with initially inoperable disease undergo resection with low procedure-related mortality. © 2018 S. Karger AG, Basel.

Gas-to-particle conversion in the particle precipitation-aided chemical vapor deposition process II. Synthesis of the perovskite oxide yttrium chromite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dieten, V.E.J. van; Dekker, J.P.; Hurkmans, E.J.

1993-11-01

In the particle precipitation-aided chemical vapor deposition process, an aerosol is formed in the gas phase at elevated temperatures. The particles are deposited on a cooled substrate. Coherent layers with a controlled porosity can be obtained by a simultaneous heterogeneous reaction, which interconnects the deposited particles. The synthesis of submicrometer powder of the perovskite oxide yttrium chromite (YCrO[sub 3]) by gas to particle conversion, which is the first step of the PP-CVD process, has been investigated, and preliminary results are shown. The powders have been synthesized using yttrium trichloride vapor (YCl[sub 3]), chromium trichloride vapor (CrCl[sub 3]), and steam andmore » oxygen as reactants. The influence of the input molar ratio of the elements on the composition and characteristics of the powders has been investigated. Phase composition has been determined by X-ray diffraction (XRD). The powders have been characterized by transmission electron microscopy (TEM) and sedimentation field flow fractionation (SF[sup 3]). At a reaction temperature of 1283 K the powders consist of the chromium sesquioxide (Cr[sub 2]O[sub 3]), or a mixture of Cr[sub 2]O[sub 3] and YCrO[sub 3]. At stoichiometeric input amounts of metal chlorides and steam the formation of YCrO[sub 3] seems to be favored. 19 refs., 6 figs., 3 tabs.« less

Thermal regulation for APDs in a 1 mm(3) resolution clinical PET camera: design, simulation and experimental verification.

PubMed

Zhai, Jinjian; Vandenbroucke, Arne; Levin, Craig S

2014-07-21

We are developing a 1 mm(3) resolution positron emission tomography camera dedicated to breast imaging. The camera collects high energy photons emitted from radioactively labeled agents introduced in the patients in order to detect molecular signatures of breast cancer. The camera comprises many layers of lutetium yttrium oxyorthosilicate (LYSO) scintillation crystals coupled to position sensitive avalanche photodiodes (PSAPDs). The main objectives of the studies presented in this paper are to investigate the temperature profile of the layers of LYSO-PSAPD detectors (a.k.a. 'fins') residing in the camera and to use these results to present the design of the thermal regulation system for the front end of the camera. The study was performed using both experimental methods and simulation. We investigated a design with a heat-dissipating fin. Three fin configurations are tested: fin with Al windows (FwW), fin without Al windows (FwoW) and fin with alumina windows (FwAW). A Fluent® simulation was conducted to study the experimentally inaccessible temperature of the PSAPDs. For the best configuration (FwW), the temperature difference from the center to a point near the edge is 1.0 K when 1.5 A current was applied to the Peltier elements. Those of FwoW and FwAW are 2.6 K and 1.7 K, respectively. We conclude that the design of a heat-dissipating fin configuration with 'aluminum windows' (FwW) that borders the scintillation crystal arrays of 16 adjacent detector modules has better heat dissipation capabilities than the design without 'aluminum windows' (FwoW) and the design with 'alumina windows' (FwAW), respectively.

Anisotropy and phonon modes from analysis of the dielectric function tensor and the inverse dielectric function tensor of monoclinic yttrium orthosilicate

NASA Astrophysics Data System (ADS)

Mock, A.; Korlacki, R.; Knight, S.; Schubert, M.

2018-04-01

We determine the frequency dependence of the four independent Cartesian tensor elements of the dielectric function for monoclinic symmetry Y2SiO5 using generalized spectroscopic ellipsometry from 40-1200 cm-1. Three different crystal cuts, each perpendicular to a principle axis, are investigated. We apply our recently described augmentation of lattice anharmonicity onto the eigendielectric displacement vector summation approach [A. Mock et al., Phys. Rev. B 95, 165202 (2017), 10.1103/PhysRevB.95.165202], and we present and demonstrate the application of an eigendielectric displacement loss vector summation approach with anharmonic broadening. We obtain an excellent match between all measured and model-calculated dielectric function tensor elements and all dielectric loss function tensor elements. We obtain 23 Au and 22 Bu symmetry long-wavelength active transverse and longitudinal optical mode parameters including their eigenvector orientation within the monoclinic lattice. We perform density functional theory calculations and obtain 23 Au symmetry and 22 Bu transverse and longitudinal optical mode parameters and their orientation within the monoclinic lattice. We compare our results from ellipsometry and density functional theory and find excellent agreement. We also determine the static and above reststrahlen spectral range dielectric tensor values and find a recently derived generalization of the Lyddane-Sachs-Teller relation for polar phonons in monoclinic symmetry materials satisfied [M. Schubert, Phys Rev. Lett. 117, 215502 (2016), 10.1103/PhysRevLett.117.215502].

Nonlinear spin conductance of yttrium iron garnet thin films driven by large spin-orbit torque

NASA Astrophysics Data System (ADS)

Thiery, N.; Draveny, A.; Naletov, V. V.; Vila, L.; Attané, J. P.; Beigné, C.; de Loubens, G.; Viret, M.; Beaulieu, N.; Ben Youssef, J.; Demidov, V. E.; Demokritov, S. O.; Slavin, A. N.; Tiberkevich, V. S.; Anane, A.; Bortolotti, P.; Cros, V.; Klein, O.

2018-02-01

We report high power spin transfer studies in open magnetic geometries by measuring the spin conductance between two nearby Pt wires deposited on top of an epitaxial yttrium iron garnet thin film. Spin transport is provided by propagating spin waves that are generated and detected by direct and inverse spin Hall effects. We observe a crossover in spin conductance from a linear transport dominated by exchange magnons (low current regime) to a nonlinear transport dominated by magnetostatic magnons (high current regime). The latter are low-damping magnetic excitations, located near the spectral bottom of the magnon manifold, with a sensitivity to the applied magnetic field. This picture is supported by microfocus Brillouin light-scattering spectroscopy. Our findings could be used for the development of controllable spin conductors by variation of relatively weak magnetic fields.

Luminescent down shifting effect of Ce-doped yttrium aluminum garnet thin films on solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Guojian; Lou, Chaogang; Kang, Jian

2015-12-21

Ce-doped yttrium aluminum garnet (YAG:Ce) thin films as luminescent down shifting (LDS) materials are introduced into the module of crystalline silicon solar cells. The films are deposited by RF magnetron sputtering on the lower surface of the quartz glass. They convert ultraviolet and blue light into yellow light. Experiments show that the introduction of YAG:Ce films improves the conversion efficiency from 18.45% of the cells to 19.27% of the module. The increasing efficiency is attributed to LDS effect of YAG:Ce films and the reduced reflection of short wavelength photons. Two intentionally selected samples with similar reflectivities are used to evaluatemore » roughly the effect of LDS alone on the solar cells, which leads to a relative increase by 2.68% in the conversion efficiency.« less

Luminescence studies of rare earth doped yttrium gadolinium mixed oxide phosphor

NASA Astrophysics Data System (ADS)

Som, S.; Choubey, A.; Sharma, S. K.

2012-09-01

This paper reports the photoluminescence and thermoluminescence properties of gamma ray induced rare earth doped yttrium gadolinium mixed oxide phosphor. The europium (Eu3+) was used as rare earth dopant. The phosphor was prepared by chemical co-precipitation method according to the formula (Y2-x-yGdx) O3: Euy3+ (x=0.5; y=0.05). The photoluminescence emission spectrum of the prepared phosphor shows intense peaks in the red region at 615 nm for 5D0→7F2 transitions and the photoluminescence excitation spectra show a broad band located around 220-270 nm for the emission wavelength fixed at 615 nm. The thermoluminescence studies were carried out after irradiating the phosphor by gamma rays in the dose range from 100 Gy to 1 KGy. In the thermoluminescence glow curves, one single peak was observed at about 300 °C of which the intensity increases linearly in the studied dose range of gamma rays. The glow peak was deconvoluted by GlowFit program and the kinetic parameters associated with the deconvoluted peaks were calculated. The kinetic parameters were also calculated by various glow curve shape and heating rate methods.

Hinged Capsulotomy--Does it Decrease Floaters After Yttrium Aluminum Garnet Laser Capsulotomy?

PubMed

Alipour, Fatemeh; Jabbarvand, Mahmoud; Hashemian, Hesam; Hosseini, Simindokht; Khodaparast, Mehdi

2015-01-01

The objective was to compare conventional circular yttrium aluminum garnet (YAG) laser capsulotomy with hinged capsulotomy to manage posterior capsular opacification (PCO). This prospective, randomized clinical trial enrolled pseudophakic patients with visually significant posterior capsule opacification. Patients were randomized to undergo posterior YAG laser capsulotomy with either conventional circular technique or a new technique with an inferior hinge. At 1-month postoperatively, patients were asked if they had any annoying floaters and the responses were compared between groups. P < 0.05 was considered statistically significant. A total of 83 patients were enrolled. Forty-three patients underwent hinged posterior YAG capsulotomy and 40 patients underwent routine circular capsulotomy. At 1-month postoperatively, there was a statistically significant decrease in annoying floaters in the group that underwent circular capsulotomy (P = 0.02). There was no statistically significant association in the total energy delivered (P = 0.4) or the number of spots (P = 0.2) and patient perception of annoying floaters. Hinged YAG capsulotomy was effective at decreasing the rate of floaters in patients with PCO.

Thermal Conductivity of a Nanoscale Yttrium Iron Garnet Thin-Film Prepared by the Sol-Gel Process

PubMed Central

2017-01-01

The thermal conductivity of a nanoscale yttrium iron garnet (Y3Fe5O12, YIG) thin-film prepared by a sol-gel method was evaluated using the ultrafast pump-probe technique in the present study. The thermoreflectance change on the surface of a 250 nm thick YIG film, induced by the irradiation of femtosecond laser pulses, was measured, and curve fitting of a numerical solution for the transient heat conduction equation to the experimental data was performed using the finite difference method in order to extract the thermal property. Results show that the film’s thermal conductivity is 22–83% higher than the properties of bulk YIG materials prepared by different fabrication techniques, reflecting the microstructural characteristics and quality of the film. PMID:28858249

Long-pulsed neodymium:yttrium-aluminum-garnet laser treatment for hypertrophic port-wine stains on the lips.

PubMed

Kono, Taro; Frederick Groff, William; Chan, Henry H; Sakurai, Hiroyuki; Yamaki, Takashi

2009-03-01

Pulsed dye laser (PDL) treatment of hypertrophic port-wine stains (PWSs) on the lips has demonstrated poor efficacy and a potential risk of dyspigmentation. PDL-resistant hypertrophic PWS may require treatment with deeper penetrating lasers such as a 1064-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. The objective of this clinical study was to evaluate the efficacy and safety of a Nd:YAG laser for the treatment of hypertrophic PWSs on the lips. Ten patients (four were male and six were female) with hypertrophic PWSs on the lips were recruited in this study. Eight patients showed good to excellent improvement without complications. In conclusion, the Nd:YAG laser is safe and effective for treating hypertrophic PWSs on the lips.

Mechanical Properties and Fracture Behaviors of the As-Extruded Mg-5Al-3Ca Alloys Containing Yttrium at Elevated Temperature.

PubMed

Son, Hyeon-Taek; Kim, Yong-Ho; Kim, Taek-Soo; Lee, Seong-Hee

2016-02-01

Effects of yttrium (Y) addition on mechanical properties and fracture behaviors of the as-extruded Mg-Al-Ca based alloys at elevated temperature were investigated by a tensile test. After hot extrusion, the average grain size was refined by Y addition and eutectic phases were broken down into fine particles. Y addition to Mg-5Al-3Ca based alloy resulted in the improvement of strength and ductility at elevated temperature due to fine grain and suppression of grain growth by formation of thermally stable Al2Y intermetallic compound.

Growth and characterization of a novel nonlinear optical borate crystal - Yttrium calcium borate (YCB)

NASA Astrophysics Data System (ADS)

Arun Kumar, R.; Arivanandhan, M.; Dhanasekaran, R.; Hayakawa, Y.

2013-06-01

A new nonlinear optical single crystal yttrium calcium borate Y2CaB10O19 (YCB) was grown for the first time from its melt. The starting materials were prepared by the solid-state reaction method. The melting point of the synthesized material was identified to be 967 °C. YCB crystal exhibits monoclinic crystal structure with the space group C2. The crystalline perfection of the grown YCB crystal was found to be good. From the UV-VIS-NIR studies, the lower cutoff wavelength of the crystal occurs below 200 nm. The functional groups of the grown crystal were assigned using the FTIR data. The second harmonic generation (SHG) of the YCB crystal was observed using a Nd:YAG laser with a fundamental wavelength of 1064 nm. The laser damage threshold value of the YCB crystal was found to be very high - 10.5 GW/cm2.

Spin valve effect of the interfacial spin accumulation in yttrium iron garnet/platinum bilayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Lichuan; Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716; Zhang, Dainan

2014-09-29

We report the spin valve effect in yttrium iron garnet/platinum (YIG/Pt) bilayers. The spin Hall effect (SHE) generates spin accumulation at the YIG/Pt interface and can be opened/closed by magnetization switching in the electrical insulator YIG. The interfacial spin accumulation was measured in both YIG/Pt and YIG/Cu/Pt structures using a planar Hall configuration. The spin valve effect remained, even after a 2 nm thick Cu layer was inserted between the YIG and Pt layers, which aimed to exclude the induced magnetization at the YIG/Pt interface. The transverse Hall voltage and switching field were dependent on the applied charge current density. Themore » origin of this behavior can be explained by the SHE induced torque exerted on the domain wall, caused by the transfer of the spin angular momentum from the spin-polarized current to the YIG magnetic moment.« less

The contact neodymium-yttrium aluminum garnet laser. A new approach to arthroscopic laser surgery.

PubMed

O'Brien, S J; Miller, D V

1990-03-01

Arthroscopic treatment of meniscal lesions has been modified as technological advances have occurred. However, alternatives to conventional arthroscopic cutting tools, including electrocautery and CO2 lasers, have thus far met with limited success. The recent development of a sapphire tip has enabled the use of the neodymium-yttrium aluminum garnet (Nd-YAG) laser in a contact mode in a saline medium. This study compares the biology of the Nd-YAG laser to that of electrocautery and scalpel techniques with respect to its effects on articular cartilage and the meniscus. The contact Nd-YAG laser has advantages over both scalpel and electrocautery with regard to its effects on articular cartilage. It also has significant biologic advantages over electrocautery for meniscal lesions. Although in its infancy in the clinical setting, the contact Nd-YAG laser represents the possible beginning of a new era for application of laser energy in arthroscopy.

A defect in inducible beta-galactosidase of B lymphocytes in the osteopetrotic (mi/mi) mouse.

PubMed Central

Yamamoto, N; Naraparaju, V R

1996-01-01

Macrophages were activated by administration of an inflammatory lipid metabolite, lysophosphatidylcholine (lyso-Pc), to wild type mice but not murine (microphthalmic) osteopetrotic (mi/mi) mutant mice. In vitro treatment of wild type mouse peritoneal cells with lyso-Pc efficiently activated macrophages whereas lyso-Pc-treatment of mi mutant mouse peritoneal cells resulted in no activation of macrophages. Generation of macrophage activating factor requires a precursor protein, serum vitamin D binding protein (DBP), and participation of lyso-Pc-inducible beta-galactosidase of B lymphocytes. Lyso-Pc-inducible beta-galactosidase of B lymphocytes was found to be defective in mi mutant mice. PMID:8881764

Effect of lysophosphatidylcholine on the filtration coefficient in intact dog lungs

NASA Technical Reports Server (NTRS)

Butler, B. D.; Davies, I.; Drake, R. E.

1989-01-01

Lysophosphatidylcholine (lyso-Pc) is a lysophospholipid normally found in low concentrations in the lung. At high concentrations lyso-Pc, instilled into the airways, causes pulmonary edema. The hypothesis was tested that the edema caused by lyso-Pc was due to an increase in pulmonary microvascular membrane permeability. In 11 anesthetized dogs, the left lower lobes (LLL) were continuously weighed while lyso-Pc (20 mM) was instilled into the LLL airways. After 30 min, the microvascular membrane fluid filtration coefficient (Kf) was determined from the relationship between the rate of LLL weight gain and the pulmonary microvascular pressure. Kf was not significantly different between the lyso-Pc-treated lobes vs control lobes. The data do not support the hypothesis that lyso-Pc, instilled into the airways, causes an increase in pulmonary microvascular permeability.

Temporary balloon occlusion of the common hepatic artery for administration of yttrium-90 resin microspheres in a patient with patent hepatoenteric collaterals.

PubMed

Mahvash, Armeen; Zaer, Navid; Shaw, Colette; Chasen, Beth; Avritscher, Rony; Murthy, Ravi

2012-02-01

The most common serious complication of yttrium-90 ((90)Y) therapy is gastrointestinal ulceration caused by extrahepatic microsphere dispersion. The authors describe the use of a balloon catheter for temporary occlusion of the common hepatic artery to reverse hepatoenteric flow for lobar administration of resin microspheres when coil embolization of a retroportal artery was impossible. At 9 months after treatment, the patient had no gastrointestinal side effects and showed a partial response. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

Evaluation of magnesium-yttrium alloy as an extraluminal tracheal stent.

PubMed

Luffy, Sarah A; Chou, Da-Tren; Waterman, Jenora; Wearden, Peter D; Kumta, Prashant N; Gilbert, Thomas W

2014-03-01

Tracheomalacia is a relatively rare problem, but can be challenging to treat, particularly in pediatric patients. Due to the presence of mechanically deficient cartilage, the trachea is unable to resist collapse under physiologic pressures of respiration, which can lead to acute death if left untreated. However, if treated, the outcome for patients with congenital tracheomalacia is quite good because the cartilage tends to spontaneously mature over a period of 12 to 18 months. The present study investigated the potential for the use of degradable magnesium-3% yttrium alloy (W3) to serve as an extraluminal tracheal stent in a canine model. The host response to the scaffold included the formation of a thin, vascularized capsule consisting of collagenous tissue and primarily mononuclear cells. The adjacent cartilage structure was not adversely affected as observed by bronchoscopic, gross, histologic, and mechanical analysis. The W3 stents showed reproducible spatial and temporal fracture patterns, but otherwise tended to corrode quite slowly, with a mix of Ca and P rich corrosion product formed on the surface and observed focal regions of pitting. The study showed that the approach to use degradable magnesium alloys as an extraluminal tracheal stent is promising, although further development of the alloys is required to improve the resistance to stress corrosion cracking and improve the ductility. Copyright © 2013 Wiley Periodicals, Inc.

Lysophosphatidylcholine hydrolases of human erythrocytes, lymphocytes, and brain: Sensitive targets of conserved specificity for organophosphorus delayed neurotoxicants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vose, Sarah C.; Center for Children's Environmental Health Research, School of Public Health, University of California, Berkeley, CA 94720; Holland, Nina T.

2007-10-01

Brain neuropathy target esterase (NTE), associated with organophosphorus (OP)-induced delayed neuropathy, has the same OP inhibitor sensitivity and specificity profiles assayed in the classical way (paraoxon-resistant, mipafox-sensitive hydrolysis of phenyl valerate) or with lysophosphatidylcholine (LysoPC) as the substrate. Extending our earlier observation with mice, we now examine human erythrocyte, lymphocyte, and brain LysoPC hydrolases as possible sensitive targets for OP delayed neurotoxicants and insecticides. Inhibitor profiling of human erythrocytes and lymphocytes gave the surprising result of essentially the same pattern as with brain. Human erythrocyte LysoPC hydrolases are highly sensitive to OP delayed neurotoxicants, with in vitro IC{sub 50} valuesmore » of 0.13-85 nM for longer alkyl analogs, and poorly sensitive to the current OP insecticides. In agricultural workers, erythrocyte LysoPC hydrolyzing activities are similar for newborn children and their mothers and do not vary with paraoxonase status but have high intersample variation that limits their use as a biomarker. Mouse erythrocyte LysoPC hydrolase activity is also of low sensitivity in vitro and in vivo to the OP insecticides whereas the delayed neurotoxicant ethyl n-octylphosphonyl fluoride inhibits activity in vivo at 1-3 mg/kg. Overall, inhibition of blood LysoPC hydrolases is as good as inhibition of brain NTE as a predictor of OP inducers of delayed neuropathy. NTE and lysophospholipases (LysoPLAs) both hydrolyze LysoPC, yet they are in distinct enzyme families with no sequence homology and very different catalytic sites. The relative contributions of NTE and LysoPLAs to LysoPC hydrolysis and clearance from erythrocytes, lymphocytes, and brain remain to be defined.« less

Observation of magnon-mediated current drag in Pt/yttrium iron garnet/Pt(Ta) trilayers

PubMed Central

Li, Junxue; Xu, Yadong; Aldosary, Mohammed; Tang, Chi; Lin, Zhisheng; Zhang, Shufeng; Lake, Roger; Shi, Jing

2016-01-01

Pure spin current, a flow of spin angular momentum without flow of any accompanying net charge, is generated in two common ways. One makes use of the spin Hall effect in normal metals (NM) with strong spin–orbit coupling, such as Pt or Ta. The other utilizes the collective motion of magnetic moments or spin waves with the quasi-particle excitations called magnons. A popular material for the latter is yttrium iron garnet, a magnetic insulator (MI). Here we demonstrate in NM/MI/NM trilayers that these two types of spin currents are interconvertible across the interfaces, predicated as the magnon-mediated current drag phenomenon. The transmitted signal scales linearly with the driving current without a threshold and follows the power-law Tn with n ranging from 1.5 to 2.5. Our results indicate that the NM/MI/NM trilayer structure can serve as a scalable pure spin current valve device which is an essential ingredient in spintronics. PMID:26932316

Observation of magnon-mediated current drag in Pt/yttrium iron garnet/Pt(Ta) trilayers.

PubMed

Li, Junxue; Xu, Yadong; Aldosary, Mohammed; Tang, Chi; Lin, Zhisheng; Zhang, Shufeng; Lake, Roger; Shi, Jing

2016-03-02

Pure spin current, a flow of spin angular momentum without flow of any accompanying net charge, is generated in two common ways. One makes use of the spin Hall effect in normal metals (NM) with strong spin-orbit coupling, such as Pt or Ta. The other utilizes the collective motion of magnetic moments or spin waves with the quasi-particle excitations called magnons. A popular material for the latter is yttrium iron garnet, a magnetic insulator (MI). Here we demonstrate in NM/MI/NM trilayers that these two types of spin currents are interconvertible across the interfaces, predicated as the magnon-mediated current drag phenomenon. The transmitted signal scales linearly with the driving current without a threshold and follows the power-law T(n) with n ranging from 1.5 to 2.5. Our results indicate that the NM/MI/NM trilayer structure can serve as a scalable pure spin current valve device which is an essential ingredient in spintronics.

Momentum-resolved observations of the phonon instability driving geometric improper ferroelectricity in yttrium manganite

DOE PAGES

Bansal, Dipanshu; Niedziela, Jennifer L.; Sinclair, Ryan; ...

2018-01-02

Magnetoelectrics offer tantalizing opportunities for devices coupling ferroelectricity and magnetism but remain difficult to realize. Breakthrough strategies could circumvent the mutually exclusive origins of magnetism and ferroelectricity by exploiting the interaction of multiple phonon modes in geometric improper and hybrid improper ferroelectrics. Yet, the proposed instability of a zone-boundary phonon mode, driving the emergence of ferroelectricity via coupling to a polar mode, remains to be directly observed. Here, we provide previously missing evidence for this scenario in the archetypal improper ferroelectric, yttrium manganite, through comprehensive scattering measurements of the atomic structure and phonons, supported with first-principles simulations. Our experiments andmore » theoretical modeling resolve the origin of the unusual temperature dependence of the polarization and rule out a reported double-step ferroelectric transition. These results emphasize the critical role of phonon anharmonicity in rationalizing lattice instabilities in improper ferroelectrics and show that including these effects in simulations could facilitate the design of magnetoelectrics.« less

Rare Earth Element Yttrium Modified Mg-Al-Zn Alloy: Microstructure, Degradation Properties and Hardness

PubMed Central

Liu, Long; Yuan, Fulai; Zhao, Mingchun; Gao, Chengde; Feng, Pei; Yang, Youwen; Yang, Sheng; Shuai, Cijun

2017-01-01

The overly-fast degradation rates of magnesium-based alloys in the biological environment have limited their applications as biodegradable bone implants. In this study, rare earth element yttrium (Y) was introduced into AZ61 magnesium alloy (Mg-6Al-1Zn wt %) to control the degradation rate by laser rapid melting. The results showed that the degradation rate of AZ61 magnesium alloy was slowed down by adding Y. This was attributed to the reduction of Mg17Al12 phase and the formation of Al2Y phase that has a more active potential, which decreased galvanic corrosion resulting from its coupling with the anodic matrix phase. Meanwhile, the hardness increased as Y contents increased due to the uniform distribution of the Al2Y and Mg17Al12 phases. However, as the Y contents increased further, the formation of excessive Al2Y phase resulted in the increasing of degradation rate and the decreasing of hardness due to its agglomeration. PMID:28772837

Effects of an erbium, chromium: yttrium, scandium, gallium, garnet laser on mucocutanous soft tissues.

PubMed

Rizoiu, I M; Eversole, L R; Kimmel, A I

1996-10-01

Lasers are effective tools for soft tissue surgery. The erbium, chromium: yttrium, scandium, gallium, garnet laser is a new system that incorporates an air-water spray. This study evaluates the cutting margins of this laser and compares healing with laser and conventional scalpel and punch biopsy-induced wounds. New Zealand white rabbits were divided into serial sacrifice groups; the tissues were grossly and microscopically analyzed after laser and convential steel surgical wounding. Wound margins were found to show minimal edge coagulation artifact and were 20 to 40 mm in width. Laser wounds showed minimal to no hemorrhage and re-epithelialization and collagenization were found to occur by day 7 in both laser and conventional groups. The new laser system is an effective soft tissue surgical device; wound healing is comparable to that associated with surgical steel wounds. The minimal edge artifact observed with this laser system should allow for the procurement of diagnostic biopsy specimens.

Observation of magnon-mediated current drag in Pt/yttrium iron garnet/Pt(Ta) trilayers

DOE PAGES

Li, Junxue; Xu, Yadong; Aldosary, Mohammed; ...

2016-03-02

Pure spin current, a flow of spin angular momentum without flow of any accompanying net charge, is generated in two common ways. One makes use of the spin Hall effect in normal metals (NM) with strong spin–orbit coupling, such as Pt or Ta. The other utilizes the collective motion of magnetic moments or spin waves with the quasi-particle excitations called magnons. A popular material for the latter is yttrium iron garnet, a magnetic insulator (MI). Here we demonstrate in NM/MI/NM trilayers that these two types of spin currents are interconvertible across the interfaces, predicated as the magnon-mediated current drag phenomenon.more » The transmitted signal scales linearly with the driving current without a threshold and follows the power-law T n with n ranging from 1.5 to 2.5. Lastly, our results indicate that the NM/MI/NM trilayer structure can serve as a scalable pure spin current valve device which is an essential ingredient in spintronics.« less

Momentum-resolved observations of the phonon instability driving geometric improper ferroelectricity in yttrium manganite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Dipanshu; Niedziela, Jennifer L.; Sinclair, Ryan

Magnetoelectrics offer tantalizing opportunities for devices coupling ferroelectricity and magnetism but remain difficult to realize. Breakthrough strategies could circumvent the mutually exclusive origins of magnetism and ferroelectricity by exploiting the interaction of multiple phonon modes in geometric improper and hybrid improper ferroelectrics. Yet, the proposed instability of a zone-boundary phonon mode, driving the emergence of ferroelectricity via coupling to a polar mode, remains to be directly observed. Here, we provide previously missing evidence for this scenario in the archetypal improper ferroelectric, yttrium manganite, through comprehensive scattering measurements of the atomic structure and phonons, supported with first-principles simulations. Our experiments andmore » theoretical modeling resolve the origin of the unusual temperature dependence of the polarization and rule out a reported double-step ferroelectric transition. These results emphasize the critical role of phonon anharmonicity in rationalizing lattice instabilities in improper ferroelectrics and show that including these effects in simulations could facilitate the design of magnetoelectrics.« less

Momentum-resolved observations of the phonon instability driving geometric improper ferroelectricity in yttrium manganite.

PubMed

Bansal, Dipanshu; Niedziela, Jennifer L; Sinclair, Ryan; Garlea, V Ovidiu; Abernathy, Douglas L; Chi, Songxue; Ren, Yang; Zhou, Haidong; Delaire, Olivier

2018-01-02

Magnetoelectrics offer tantalizing opportunities for devices coupling ferroelectricity and magnetism but remain difficult to realize. Breakthrough strategies could circumvent the mutually exclusive origins of magnetism and ferroelectricity by exploiting the interaction of multiple phonon modes in geometric improper and hybrid improper ferroelectrics. Yet, the proposed instability of a zone-boundary phonon mode, driving the emergence of ferroelectricity via coupling to a polar mode, remains to be directly observed. Here, we provide previously missing evidence for this scenario in the archetypal improper ferroelectric, yttrium manganite, through comprehensive scattering measurements of the atomic structure and phonons, supported with first-principles simulations. Our experiments and theoretical modeling resolve the origin of the unusual temperature dependence of the polarization and rule out a reported double-step ferroelectric transition. These results emphasize the critical role of phonon anharmonicity in rationalizing lattice instabilities in improper ferroelectrics and show that including these effects in simulations could facilitate the design of magnetoelectrics.

Temporary Arterial Balloon Occlusion as an Adjunct to Yttrium-90 Radioembolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagspiel, Klaus D., E-mail: kdh2n@virginia.edu; Nambiar, Ashwin, E-mail: uvashwin@gmail.com; Hagspiel, Lauren M., E-mail: lmh4gg@virginia.edu

2013-06-15

Purpose. This study was designed to describe the technique of arterial occlusion using a temporary occlusion balloon system as an alternative to coil occlusion during Yttrium-90 radioembolization of hepatic tumors. Methods. Review of charts, angiography, and follow-up imaging studies of consecutive patients undergoing oncological embolization procedures in which a HyperForm system (ev3 Neurovascular, Irvine, CA) was used. Intraprocedural target vessel occlusion and patency of the target vessel on follow-up were recorded. Clinical data and Bremsstrahlung scans were reviewed for evidence of nontarget embolization. Results. Four radioembolization procedures were performed in three patients (all female, age 48-54 (mean 52) years). Fivemore » arteries were temporarily occluded (three gastroduodenal arteries, one right gastric artery, and one cystic artery). All radioembolization procedures were successfully completed. Follow-up imaging (either digital subtraction angiography (DSA) or computed tomography angiography (CTA)) was available for all patients between 28-454 (mean 183) days following the procedure, demonstrating all five vessels to be patent. No clinical or imaging evidence for nontarget embolization was found. Conclusions. Temporary balloon occlusion of small and medium-sized arteries during radioembolization allows safe therapy with preserved postprocedural vessel patency on early and midterm follow-up.« less

Rapid screening for lipid storage disorders using biochemical markers. Expert center data and review of the literature.

PubMed

Voorink-Moret, M; Goorden, S M I; van Kuilenburg, A B P; Wijburg, F A; Ghauharali-van der Vlugt, J M M; Beers-Stet, F S; Zoetekouw, A; Kulik, W; Hollak, C E M; Vaz, F M

2018-02-01

In patients suspected of a lipid storage disorder (sphingolipidoses, lipidoses), confirmation of the diagnosis relies predominantly on the measurement of specific enzymatic activities and genetic studies. New UPLC-MS/MS methods have been developed to measure lysosphingolipids and oxysterols, which, combined with chitotriosidase activity may represent a rapid first tier screening for lipid storage disorders. A lysosphingolipid panel consisting of lysoglobotriaosylceramide (LysoGb3), lysohexosylceramide (LysoHexCer: both lysoglucosylceramide and lysogalactosylceramide), lysosphingomyelin (LysoSM) and its carboxylated analogue lysosphingomyelin-509 (LysoSM-509) was measured in control subjects and plasma samples of predominantly untreated patients affected with lipid storage disorders (n=74). In addition, the oxysterols cholestane-3β,5α,6β-triol and 7-ketocholesterol were measured in a subset of these patients (n=36) as well as chitotriosidase activity (n=43). A systematic review of the literature was performed to assess the usefulness of these biochemical markers. Specific elevations of metabolites, i.e. without overlap between controls and other lipid storage disorders, were found for several lysosomal storage diseases: increased LysoSM levels in acid sphingomyelinase deficiency (Niemann-Pick disease type A/B), LysoGb3 levels in males with classical phenotype Fabry disease and LysoHexCer (i.e. lysoglucosylceramide/lysogalactosylceramide) in Gaucher and Krabbe diseases. While elevated levels of LysoSM-509 and cholestane-3β,5α,6β-triol did not discriminate between Niemann Pick disease type C and acid sphingomyelinase deficiency, LysoSM-509/LysoSM ratio was specifically elevated in Niemann-Pick disease type C. In Gaucher disease type I, mild increases in several lysosphingolipids were found including LysoGb3 with levels in the range of non-classical Fabry males and females. Chitotriosidase showed specific elevations in symptomatic Gaucher disease, and was mildly

Hinged Capsulotomy – Does it Decrease Floaters After Yttrium Aluminum Garnet Laser Capsulotomy?

PubMed Central

Alipour, Fatemeh; Jabbarvand, Mahmoud; Hashemian, Hesam; Hosseini, Simindokht; Khodaparast, Mehdi

2015-01-01

Objectives: The objective was to compare conventional circular yttrium aluminum garnet (YAG) laser capsulotomy with hinged capsulotomy to manage posterior capsular opacification (PCO). Materials and Methods: This prospective, randomized clinical trial enrolled pseudophakic patients with visually significant posterior capsule opacification. Patients were randomized to undergo posterior YAG laser capsulotomy with either conventional circular technique or a new technique with an inferior hinge. At 1-month postoperatively, patients were asked if they had any annoying floaters and the responses were compared between groups. P < 0.05 was considered statistically significant. Results: A total of 83 patients were enrolled. Forty-three patients underwent hinged posterior YAG capsulotomy and 40 patients underwent routine circular capsulotomy. At 1-month postoperatively, there was a statistically significant decrease in annoying floaters in the group that underwent circular capsulotomy (P = 0.02). There was no statistically significant association in the total energy delivered (P = 0.4) or the number of spots (P = 0.2) and patient perception of annoying floaters. Conclusion: Hinged YAG capsulotomy was effective at decreasing the rate of floaters in patients with PCO. PMID:26180476

Water flow on erbium:yttrium-aluminum-garnet laser irradiation: effects on dental tissues.

PubMed

Colucci, Vivian; do Amaral, Flávia Lucisano Botelho; Pécora, Jesus Djalma; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

2009-09-01

Since lasers were introduced in dentistry, there has been considerable advancement in technology. Several wavelengths have been investigated as substitutes for high-speed air turbine. Owing to its high absorbability in water and hydroxyapatite, the erbium:yttrium-aluminum-garnet (Er:YAG) laser has been of great interest among dental practitioners and scientists. In spite of its great potential for hard tissue ablation, Er:YAG laser effectiveness and safety is directly related to an adequate setting of the working patterns. It is assumed that the ablation rate is influenced by certain conditions, such as water content of the target tissue, and laser parameters. It has been shown that Er:YAG irradiation with water coolant attenuates temperature rise and, hence, minimizes the risk of thermally induced pulp injury. It also increases ablation efficiency and enhances adhesion to the lased dental tissue. The aim of this review was to obtain insights into the ablation process and to discuss the effects of water flow on dental tissue ablation using Er:YAG laser.

Precision Timing Calorimeter for High Energy Physics

DOE PAGES

Anderson, Dustin; Apresyan, Artur; Bornheim, Adolf; ...

2016-04-01

Here, we present studies on the performance and characterization of the time resolution of LYSO-based calorimeters. Results for an LYSO sampling calorimeter and an LYSO-tungsten Shashlik calorimeter are presented. We also demonstrate that a time resolution of 30 ps is achievable for the LYSO sampling calorimeter. Timing calorimetry is described as a tool for mitigating the effects due to the large number of simultaneous interactions in the high luminosity environment foreseen for the Large Hadron Collider.

Crystal identification for a dual-layer-offset LYSO based PET system via Lu-176 background radiation and mean shift algorithm

NASA Astrophysics Data System (ADS)

Wei, Qingyang; Ma, Tianyu; Xu, Tianpeng; Zeng, Ming; Gu, Yu; Dai, Tiantian; Liu, Yaqiang

2018-01-01

Modern positron emission tomography (PET) detectors are made from pixelated scintillation crystal arrays and readout by Anger logic. The interaction position of the gamma-ray should be assigned to a crystal using a crystal position map or look-up table. Crystal identification is a critical procedure for pixelated PET systems. In this paper, we propose a novel crystal identification method for a dual-layer-offset LYSO based animal PET system via Lu-176 background radiation and mean shift algorithm. Single photon event data of the Lu-176 background radiation are acquired in list-mode for 3 h to generate a single photon flood map (SPFM). Coincidence events are obtained from the same data using time information to generate a coincidence flood map (CFM). The CFM is used to identify the peaks of the inner layer using the mean shift algorithm. The response of the inner layer is deducted from the SPFM by subtracting CFM. Then, the peaks of the outer layer are also identified using the mean shift algorithm. The automatically identified peaks are manually inspected by a graphical user interface program. Finally, a crystal position map is generated using a distance criterion based on these peaks. The proposed method is verified on the animal PET system with 48 detector blocks on a laptop with an Intel i7-5500U processor. The total runtime for whole system peak identification is 67.9 s. Results show that the automatic crystal identification has 99.98% and 99.09% accuracy for the peaks of the inner and outer layers of the whole system respectively. In conclusion, the proposed method is suitable for the dual-layer-offset lutetium based PET system to perform crystal identification instead of external radiation sources.

Nanophotonic photon echo memory based on rare-earth-doped crystals

NASA Astrophysics Data System (ADS)

Zhong, Tian; Kindem, Jonathan; Miyazono, Evan; Faraon, Andrei; Caltech nano quantum optics Team

2015-03-01

Rare earth ions (REIs) are promising candidates for implementing solid-state quantum memories and quantum repeater devices. Their high spectral stability and long coherence times make REIs a good choice for integration in an on-chip quantum nano-photonic platform. We report the coupling of the 883 nm transition of Neodymium (Nd) to a Yttrium orthosilicate (YSO) photonic crystal nano-beam resonator, achieving Purcell enhanced spontaneous emission by 21 times and increased optical absorption. Photon echoes were observed in nano-beams of different doping concentrations, yielding optical coherence times T2 up to 80 μs that are comparable to unprocessed bulk samples. This indicates the remarkable coherence properties of Nd are preserved during nanofabrication, therefore opening the possibility of efficient on-chip optical quantum memories. The nano-resonator with mode volume of 1 . 6(λ / n) 3 was fabricated using focused ion beam, and a quality factor of 3200 was measured. Purcell enhanced absorption of 80% by an ensemble of ~ 1 × 106 ions in the resonator was measured, which fulfills the cavity impedance matching condition that is necessary to achieve quantum storage of photons with unity efficiency.

A PET detector prototype based on digital SiPMs and GAGG scintillators.

PubMed

Schneider, Florian R; Shimazoe, Kenji; Somlai-Schweiger, Ian; Ziegler, Sibylle I

2015-02-21

Silicon Photomultipliers (SiPM) are interesting light sensors for Positron Emission Tomography (PET). The detector signal of analog SiPMs is the total charge of all fired cells. Energy and time information have to be determined with dedicated readout electronics. Philips Digital Photon Counting has developed a SiPM with added electronics on cell level delivering a digital value of the time stamp and number of fired cells. These so called Digital Photon Counters (DPC) are fully digital devices. In this study, the feasibility of using DPCs in combination with LYSO (Lutetium Yttrium Oxyorthosilicate) and GAGG (Gadolinium Aluminum Gallium Garnet) scintillators for PET is tested. Each DPC module has 64 channels with 3.2 × 3.8775 mm(2), comprising 3200 cells each. GAGG is a recently developed scintillator (Zeff = 54, 6.63 g cm(-3), 520 nm peak emission, 46 000 photons MeV(-1), 88 ns (92%) and 230 ns (8%) decay times, non-hygroscopic, chemically and mechanically stable). Individual crystals of 2 × 2 × 6 mm(3) were coupled onto each DPC pixel. LYSO coupled to the DPC results in a coincidence time resolution (CTR) of 171 ps FWHM and an energy resolution of 12.6% FWHM at 511 keV. Using GAGG, coincidence timing is 310 ps FWHM and energy resolution is 8.5% FWHM. A PET detector prototype with 2 DPCs equipped with a GAGG array matching the pixel size (3.2 × 3.8775 × 8 mm(3)) was assembled. To emulate a ring of 10 modules, objects are rotated in the field of view. CTR of the PET is 619 ps and energy resolution is 9.2% FWHM. The iterative MLEM reconstruction is based on system matrices calculated with an analytical detector response function model. A phantom with rods of different diameters filled with (18)F was used for tomographic tests.

A PET detector prototype based on digital SiPMs and GAGG scintillators

NASA Astrophysics Data System (ADS)

Schneider, Florian R.; Shimazoe, Kenji; Somlai-Schweiger, Ian; Ziegler, Sibylle I.

2015-02-01

Silicon Photomultipliers (SiPM) are interesting light sensors for Positron Emission Tomography (PET). The detector signal of analog SiPMs is the total charge of all fired cells. Energy and time information have to be determined with dedicated readout electronics. Philips Digital Photon Counting has developed a SiPM with added electronics on cell level delivering a digital value of the time stamp and number of fired cells. These so called Digital Photon Counters (DPC) are fully digital devices. In this study, the feasibility of using DPCs in combination with LYSO (Lutetium Yttrium Oxyorthosilicate) and GAGG (Gadolinium Aluminum Gallium Garnet) scintillators for PET is tested. Each DPC module has 64 channels with 3.2 × 3.8775 mm2, comprising 3200 cells each. GAGG is a recently developed scintillator (Zeff = 54, 6.63 g cm-3, 520 nm peak emission, 46 000 photons MeV-1, 88 ns (92%) and 230 ns (8%) decay times, non-hygroscopic, chemically and mechanically stable). Individual crystals of 2 × 2 × 6 mm3 were coupled onto each DPC pixel. LYSO coupled to the DPC results in a coincidence time resolution (CTR) of 171 ps FWHM and an energy resolution of 12.6% FWHM at 511 keV. Using GAGG, coincidence timing is 310 ps FWHM and energy resolution is 8.5% FWHM. A PET detector prototype with 2 DPCs equipped with a GAGG array matching the pixel size (3.2 × 3.8775 × 8 mm3) was assembled. To emulate a ring of 10 modules, objects are rotated in the field of view. CTR of the PET is 619 ps and energy resolution is 9.2% FWHM. The iterative MLEM reconstruction is based on system matrices calculated with an analytical detector response function model. A phantom with rods of different diameters filled with 18F was used for tomographic tests.

High-resolution structural characterization and magnetic properties of epitaxial Ce-doped yttrium iron garnet thin films

NASA Astrophysics Data System (ADS)

Li, Zhong; Vikram Singh, Amit; Rastogi, Ankur; Gazquez, Jaume; Borisevich, Albina Y.; Mishra, Rohan; Gupta, Arunava

2017-07-01

Thin films of magnetic garnet materials, e.g. yttrium iron garnet (Y3Fe5O12, YIG), are useful for a variety of applications including microwave integrated circuits and spintronics. Substitution of rare earth ions, such as cerium, is known to enhance the magneto-optic Kerr effect (MOKE) as compared to pure YIG. Thin films of Ce0.75Y2.25Fe5O12 (Ce:YIG) have been grown using the pulsed laser deposition (PLD) technique and their crystal structure examined using high resolution scanning transmission electron microscopy. Homogeneous substitution of Ce in YIG, without oxidation to form a separate CeO2 phase, can be realized in a narrow process window with resulting enhancement of the MOKE signal. The thermally generated signal due to spin Seebeck effect for the optimally doped Ce:YIG films has also been investigated.

A photostable near-infrared fluorescent tracker with pH-independent specificity to lysosomes for long time and multicolor imaging.

PubMed

Zhang, Xinfu; Wang, Chao; Han, Zhuo; Xiao, Yi

2014-12-10

A new boron-dipyrromethene-based lysosome tracker, Lyso-NIR, is facilely synthesized. Besides the intensive near-infrared (NIR) fluorescence and high photostability, Lyso-NIR shows the capability to stably localize in lysosomes, which is independent of the local pH. Lyso-NIR does not have the problematic alkalization effect suffered by the commonly used lysotrackers; thus, it shows ignorable cytotoxicity and slightly affects normal physiological functions of lysosomes. The above advantages of Lyso-NIR make it feasible to track lysosomes' dynamic changes in a relatively long time during the full cellular processes such as apoptosis, heavy metal stimulation, and endocytosis, as is demonstrated in this work. Moreover, Lyso-NIR's narrow NIR emission at 740 nm with a full width at half-maximum smaller than 50 nm makes it easy to avoid the crosstalk with the emissions from other common fluorescent probes, which strengthens Lyso-NIR's competitiveness as a standard lysosome tracker for multicolor bioimaging.

Investigation for surface resistance of yttrium-barium-copper-oxide thin films on various substrates for microwave applications

NASA Astrophysics Data System (ADS)

Yao, Hongjun

High temperature superconducting (HTS) materials such as YBCO (Yttrium-Barium-Copper-Oxide) are very attractive in microwave applications because of their extremely low surface resistance. In the proposed all-HTS tunable filter, a layer of HTS thin film on a very thin substrate (100 mum) is needed to act as the toractor that can be rotated to tune the frequency. In order to provide more substrate candidates that meet both electrical and mechanical requirements for this special application, surface resistance of YBCO thin films on various substrates was measured using microstrip ring resonator method. For alumina polycrystalline substrate, a layer of YSZ (Yttrium stabilized Zirconia) was deposited using IBAD (ion beam assisted deposition) method prior to YBCO deposition. The surface resistance of the YBCO thin film on alumina was found to be 22 mO due to high-angle grain boundary problem caused by the mixed in-plane orientations and large FWHM (full width at half maximum) of the thin film. For YBCO thin films on a YSZ single crystal substrate, the surface resistance showed even higher value of 30 mO because of the mixed in-plane orientation problem. However, by annealing the substrate in 200 Torr oxygen at 730°C prior to deposition, the in-plane orientation of YBCO thin films can be greatly improved. Therefore, the surface resistance decreased to 1.4 mO, which is still more than an order higher than the reported best value. The YBCO thin films grown on LaAlO3 single crystal substrate showed perfect in-plane orientation with FWHM less 1°. The surface resistance was as low as 0.032 mO. A tunable spiral resonator made of YBCO thin film on LaAlO3 single crystal substrate demonstrated that the resonant frequency can be tuned in a rang as large as 500 MHz by changing the gap between toractor and substrate. The Q-factor was more than 12,000, which ensured the extraordinarily high sensitivity for the proposed all-HTS tunable filter.

Enhancement of thermal stability and water resistance in yttrium-doped GeO{sub 2}/Ge gate stack

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Cimang, E-mail: cimang@adam.t.u-tokyo.ac.jp; Hyun Lee, Choong; Zhang, Wenfeng

2014-03-03

We have systematically investigated the material and electrical properties of yttrium-doped GeO{sub 2} (Y-GeO{sub 2}) on Germanium (Ge). A significant improvement of both thermal stability and water resistance were demonstrated by Y-GeO{sub 2}/Ge stack, compared to that of pure GeO{sub 2}/Ge stack. The excellent electrical properties of Y-GeO{sub 2}/Ge stacks with low D{sub it} were presented as well as enhancement of dielectric constant in Y-GeO{sub 2} layer, which is beneficial for further equivalent oxide thickness scaling of Ge gate stack. The improvement of thermal stability and water resistance are discussed both in terms of the Gibbs free energy lowering andmore » network modification of Y-GeO{sub 2}.« less

Lysophosphatidylcholine-induced cytotoxicity in osteoblast-like MG-63 cells: involvement of transient receptor potential vanilloid 2 (TRPV2) channels.

PubMed

Fallah, Abdallah; Pierre, Rachel; Abed, Elie; Moreau, Robert

2013-01-01

Epidemiological studies indicate that patients suffering from atherosclerosis are predisposed to develop osteoporosis. Accordingly, atherogenic determinants such as oxidized low density lipoprotein (OxLDL) particles have been shown to alter bone cell functions. In this work, we investigated the cytotoxicity of lysophosphatidylcholine (lysoPC), a major phospholipid component generated upon LDL oxidation, on bone-forming MG-63 osteoblast-like cells. Cell viability was reduced by lysoPC in a concentration-dependent manner with a LC50 of 18.7±0.7 μM. LysoPC-induced cell death was attributed to induction of both apoptosis and necrosis. Since impairment of intracellular calcium homeostasis is often involved in mechanism of cell death, we determined the involvement of calcium in lysoPC-induced cytotoxicity. LysoPC promoted a rapid and transient increase in intracellular calcium attributed to mobilization from calcium stores, followed by a sustained influx. Intracellular calcium mobilization was associated to phospholipase C (PLC)-dependent mobilization of calcium from the endoplasmic reticulum since inhibition of PLC or calcium depletion of reticulum endoplasmic with thapsigargin prevented the calcium mobilization. The calcium influx induced by lysoPC was abolished by inhibition of transient receptor potential vanilloid (TRPV) channels with ruthenium red whereas gadolinium, which inhibits canonical TRP (TRPC) channels, was without effect. Accordingly, expression of TRPV2 and TRPV4 were shown in MG-63 cells. The addition of TRPV2 inhibitor Tranilast in the incubation medium prevent the calcium influx triggered by lysoPC and reduced lysoPC-induced cytotoxicity whereas TRPV4 inhibitor RN 1734 was without effect, which confirms the involvement of TRPV2 activation in lysoPC-induced cell death.

High-efficiency control of spin-wave propagation in ultra-thin yttrium iron garnet by the spin-orbit torque

DOE Office of Scientific and Technical Information (OSTI.GOV)

Evelt, M.; Demidov, V. E., E-mail: demidov@uni-muenster.de; Bessonov, V.

2016-04-25

We study experimentally with submicrometer spatial resolution the propagation of spin waves in microscopic waveguides based on the nanometer-thick yttrium iron garnet and Pt layers. We demonstrate that by using the spin-orbit torque, the propagation length of the spin waves in such systems can be increased by nearly a factor of 10, which corresponds to the increase in the spin-wave intensity at the output of a 10 μm long transmission line by three orders of magnitude. We also show that, in the regime, where the magnetic damping is completely compensated by the spin-orbit torque, the spin-wave amplification is suppressed by themore » nonlinear scattering of the coherent spin waves from current-induced excitations.« less

PEO-b-P4VP/Yttrium Hydroxide Hybrid Nanotubes as Supporter for Catalyst Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Yang, Qian; Chen, Dao-yong

2012-06-01

The adsorption of poly (ethylene oxide)-b-poly(4-vinylpyridine)(PEO-b-P4VP) micelles onto the surface of yttrium hydroxide nanotubes (YNTs) resulted in the hybrid nanotubes with a dense P4VP inner layer and a stretched PEO outer layer surrounding YNTs. The dense P4VP layer was further stabilized by the crosslinking using 1,4-dibromobutane as the crosslinker. Then, the crosslinked hybrid nanotubes (CHNTs) were used as a novel nano supporter for loading the catalyst gold nanoparticles (GNPs) within the crosslinked P4VP layer. The resultant GNPs/CHNTs (GNTs loaded on CHNTs) were applied to catalyze the reduction reaction of p-nitrophenol. The results indicate that this novel nano supporter has advantages such as good dispersity in the suspension, high capacity in loading GNPs (0.87 mmol/g), high catalytic activity of the loaded GNPs (12.9 μmol-1min-1), and good reusability of GNTs/CHNTs.

Generation of coherent spin-wave modes in yttrium iron garnet microdiscs by spin–orbit torque

PubMed Central

Collet, M.; de Milly, X.; d'Allivy Kelly, O.; Naletov, V. V.; Bernard, R.; Bortolotti, P.; Ben Youssef, J.; Demidov, V. E.; Demokritov, S. O.; Prieto, J. L.; Muñoz, M.; Cros, V.; Anane, A.; de Loubens, G.; Klein, O.

2016-01-01

In recent years, spin–orbit effects have been widely used to produce and detect spin currents in spintronic devices. The peculiar symmetry of the spin Hall effect allows creation of a spin accumulation at the interface between a metal with strong spin–orbit interaction and a magnetic insulator, which can lead to a net pure spin current flowing from the metal into the insulator. This spin current applies a torque on the magnetization, which can eventually be driven into steady motion. Tailoring this experiment on extended films has proven to be elusive, probably due to mode competition. This requires the reduction of both the thickness and lateral size to reach full damping compensation. Here we show clear evidence of coherent spin–orbit torque-induced auto-oscillation in micron-sized yttrium iron garnet discs of thickness 20 nm. Our results emphasize the key role of quasi-degenerate spin-wave modes, which increase the threshold current. PMID:26815737

Rare earth activated yttrium aluminate phosphors with modulated luminescence.

PubMed

Muresan, L E; Popovici, E J; Perhaita, I; Indrea, E; Oro, J; Casan Pastor, N

2016-06-01

Yttrium aluminate (Y3 A5 O12 ) was doped with different rare earth ions (i.e. Gd(3+) , Ce(3+) , Eu(3+) and/or Tb(3+) ) in order to obtain phosphors (YAG:RE) with general formula,Y3-x-a Gdx REa Al5 O12 (x = 0; 1.485; 2.97 and a = 0.03). The synthesis of the phosphor samples was done using the simultaneous addition of reagents technique. This study reveals new aspects regarding the influence of different activator ions on the morpho-structural and luminescent characteristics of garnet type phosphor. All YAG:RE phosphors are well crystallized powders containing a cubic-Y3 Al5 O12 phase as major component along with monoclinic-Y4 Al2 O9 and orthorhombic-YAlO3 phases as the impurity. The crystallites dimensions of YAG:RE phosphors vary between 38 nm and 88 nm, while the unit cell slowly increase as the ionic radius of the activator increases. Under UV excitation, YAG:Ce exhibits yellow emission due to electron transition in Ce(3+) from the 5d level to the ground state levels ((2) F5/2 , (2) F7/2 ). The emission intensity of Ce(3+) is enhanced in the presence of the Tb(3+) ions and is decreased in the presence of Eu(3+) ions due to some radiative or non-radiative processes that take place between activator ions. By varying the rare earth ions, the emission colour can be modulated from green to white and red. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Improved Yttrium and Zirconium Abundances in Metal-Poor Stars

NASA Astrophysics Data System (ADS)

Violante, Renata; Biemont, E.; Cowan, J. J.; Sneden, C.

2012-01-01

Abstract We present new abundances of the lighter n-capture elements, Yttrium (Z=39) and Zirconium (Z=40) in the very metal poor, r-process rich stars BD+17 3248 and HD 221170. Very accurate abundances were obtained by use of the new transition probabilities for Y II published by Biémont et al. 2011, and Zr II by Malcheva et al. 2006, and by expanding the number of transitions employed for each element. For example, in BD+17 3248, we find log ɛπσιλον=-0.03 +/- 0.03 (σιγμα=0.15, from 23 lines) for Y II. As for Zr II, log ɛπσιλον = 0.65 +/- 0.03 (σɛγμα = 0.1, from 13 lines). The resulting abundance ratio is log ɛπσιλον [Y/Zr] = -0.68 +/- 0.05. The results for HD 221170 are in accord with those of BD+17 3248. The quantity of lines used to form the abundance means has increased significantly since the original studies of these stars, resulting in more trustworthy abundances. These observed abundance ratios are in agreement with an r-process-only value predicted from stellar models, but is under-abundant compared to an empirical model derived from direct analyses of meteoritic material. This ambiguity should stimulate further nucleosynthetic analysis to explain this abundance ratio. We would like to extend our gratitude to NSF grant AST-0908978 and the University of Texas Astronomy Department Rex G. Baker, Jr. Endowment for their financial support in this project.

Clinical significance of plasma globotriaosylsphingosine levels in Chinese patients with Fabry disease.

PubMed

Ouyang, Yan; Chen, Bing; Pan, Xiaoxia; Wang, Zhaohui; Ren, Hong; Xu, Yaowen; Ni, Liyan; Yu, Xialian; Yang, Li; Chen, Nan

2018-04-01

Although plasma globotriaosylsphingosine (lyso-Gb3) is a promising biomarker of Fabry disease (FD), few studies have assessed the impact of lyso-Gb3 in patients with FD. A total of 38 patients diagnosed with FD at Ruijin Hospital between January 2012 and December 2014 were recruited in the current study. An additional 120 unrelated healthy individuals were selected as healthy controls. A simplified liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was performed to determine lyso-Gb3 levels in plasma. Protein precipitation and glycolipid extraction were conducted using acetone/methanol. Clinical performance, including diagnostic value and disease surveillance, were compared between plasma lyso-Gb3 levels and α-galactosidase A (α-gal A) enzyme activity. The overall coefficient of variation values between inter- and intra-days varied between 2.8 and 18.9% and linearity correlation coefficients were ≥0.99 for all assays. Therefore, the effectiveness of the LC-MS/MS method was validated. Furthermore, a cut-off value of 0.81 ng/ml plasma lyso-Gb3 was able to separate patients with FD from healthy individuals. The sensitivity of this cut-off was 94.7% and the specificity was 100%. Compared with α-gal A enzyme activity, the diagnostic rate of patients assessed using plasma lyso-Gb3 levels was similar; however, there was a tighter correlation between plasma lyso-Gb3 levels and the mainz severity score index score in male patients (r=0.711 vs. r=-0.687). The sensitivity of plasma lyso-Gb3 in diagnosing female patients with FD was higher than α-gal A enzyme activity (82.4 vs. 23.5%). To the best of our knowledge, the present study is the first to report the effectiveness of plasma lyso-Gb3 levels in diagnosing Chinese patients with FD. Using α-gal A activity as a reference, the results of current study indicated that plasma lyso-Gb3 levels are more useful at diagnosing female patients with FD. Furthermore, plasma lyso-Gb3 levels are more suitable at

Two-Photon Fluorescent Probe for Monitoring Autophagy via Fluorescence Lifetime Imaging.

PubMed

Hou, Liling; Ning, Peng; Feng, Yan; Ding, Yaqi; Bai, Lei; Li, Lin; Yu, Haizhu; Meng, Xiangming

2018-06-19

We reported the first lysosome targeted two-photon fluorescent probe (Lyso-NP) as a viscosity probe for monitoring autophagy. The fluorescence lifetime of Lyso-NP exhibited an excellent linear relationship with viscosity value ( R 2 = 0.99, x = 0.39). Lyso-NP also showed the specific capability for imaging lysosomal viscosity under two-photon excitation at 860 nm along with good biocompatibility. More importantly, Lyso-NP could be used to monitor the autophagy process in living cells by quantitatively detecting lysosomal viscosity changes during the membrane fusion process via two-photon fluorescence lifetime imaging.

Visible emission from bismuth-doped yttrium oxide thin films for lighting and display applications.

PubMed

Scarangella, Adriana; Fabbri, Filippo; Reitano, Riccardo; Rossi, Francesca; Priolo, Francesco; Miritello, Maria

2017-12-11

Due to the great development of light sources for several applications from displays to lighting, great efforts are devoted to find stable and efficient visible emitting materials. Moreover, the requirement of Si compatibility could enlarge the range of applications inside microelectronic chips. In this scenario, we have studied the emission properties of bismuth doped yttrium oxide thin films grown on crystalline silicon. Under optical pumping at room temperature a stable and strong visible luminescence has been observed. In particular, by the involvement of Bi ions in the two available lattice sites, the emission can be tuned from violet to green by changing the excitation wavelength. Moreover, under electron beam at low accelerating voltages (3 keV) a blue emission with high efficiency and excellent stability has been recorded. The color is generated by the involvement of Bi ions in both the lattice sites. These peculiarities make this material interesting as a luminescent medium for applications in light emitting devices and field emission displays by opening new perspectives for the realization of silicon-technology compatible light sources operating at room temperature.

A silica optical fiber doped with yttrium aluminosilicate nanoparticles for supercontinuum generation

NASA Astrophysics Data System (ADS)

Cheng, Tonglei; Liao, Meisong; Xue, Xiaojie; Li, Jiang; Gao, Weiqing; Li, Xia; Chen, Danping; Zheng, Shupei; Pan, Yubai; Suzuki, Takenobu; Ohishi, Yasutake

2016-03-01

We design and fabricate a silica optical fiber doped with yttrium aluminosilicate (YAS, Y2O3-Al2O3-SiO2) nanoparticles in the core. The optical fiber is drawn directly from a silica tube with YAG (Y3Al5O12) ceramics and silica powders (the molar ratio 1:18) in the core at the temperature of ∼1950 °C. The YAS nanoparticles are formed during the optical fiber drawing process. Supercontinuum (SC) generation in the optical fiber is investigated at different pump wavelength. At the pump wavelength of ∼1750 nm which is in the deep anomalous dispersion region, SC spectrum evolution is mainly due to multiple solitons and dispersive waves (DWs), and three pairs of multiple optical solitons and DWs are observed. When the pump wavelength shifts to ∼1500 nm which is close to the zero-dispersion wavelength (ZDW), flattened SC spectrum with ±7 dB uniformity is obtained at the wavelength region of ∼990-1980 nm, and only one obvious soliton and DW are observed. At the pump wavelength of ∼1100 nm, a narrow SC spectrum from ∼1020 to 1180 nm is obtained in the normal dispersion region due to self-phase modulation (SPM) effect.

Comparison of the marginal fit of milled yttrium stabilized zirconium dioxide crowns obtained by scanning silicone impressions and by scanning stone replicas.

PubMed

Aranda Yus, Estefanía; Cantarell, Josep Maria Anglada; Miñarro Alonso, Antonio

2018-06-01

To determine the discrepancy in monolithic zirconium dioxide crowns made with computer-aided design and computer-aided manufacturing (CAD/CAM) systems by comparing scans of silicone impressions and of master casts. From a Cr-Co master die of a first upper left molar, 30 silicone impressions were taken. The 30 silicone impressions were scanned with the laboratory scanner, thus obtaining 30 milled monolithic yttrium stabilized zirconium dioxide (YSZD) crowns (the silicone group). They were poured and the working models were scanned, obtaining 30 milled monolithic yttrium stabilized zirconium dioxide (YSZD) crowns (the plaster group). Three predetermined points were analyzed in each side of the crown (Mesial, Distal ,Vestibular and Palatal), and the marginal fit was evaluated with SEM (×600). The response variable is the discrepancy from the master model. A repeated measures ANOVA with two within subject factors was performed to study significance of main factors and interaction. Mean marginal discrepancy was 22.42±35.65 µm in the silicone group and 8.94±14.69 µm in the plaster group. The statistical analysis showed significant differences between the two groups and also among the four aspects. Interaction was also significant ( P =.02). The mean marginal fit values of the two groups were within the clinically acceptable values. Significant differences were found between the groups according to the aspects studied. Various factors influenced the accuracy of digitizing, such as the design, the geometry, and the preparation guidance, as well as the texture, roughness and the color of the scanned material.

High-temperature corrosion of iron-aluminum and iron-aluminum-yttrium alloys

NASA Astrophysics Data System (ADS)

Insoo, Kim

The high-temperature corrosion behavior of Fe3Al alloy has been investigated by conducting two studies: (1) corrosion of Fe 3Al and Fe3Al-Y alloys in oxidizing atmosphere and (2) corrosion of Fe3Al in mixed chlorine/oxygen environments. In the first study, oxidation of the two alloys, Fe-14.3 wt% Al and Fe-14.1 wt% Al-0.3 wt% Y, was carried out in the temperature range of 800 to 1100°C to investigate the general oxidation behavior of Fe3Al and the effect of yttrium on the oxidation of Fe3Al in terms of oxidation kinetics, oxide scale adhesion and microstructure. At lower temperatures (<1000°C), the oxidation rate of the two alloys was nearly identical, and the parabolic rate constant obtained as a function of temperature was Kp = 5128 exp[--39500 (cal/mol)/RT] mg2/cm4 h. At higher temperatures, however, yttrium-added Fe3Al alloy exhibited lower oxidation rate and much more improved oxide adhesion. The lower oxidation rate observed in Fe3Al-Y alloy seems to be due to the followings: (1) a decrease in aluminum diffusion through alumina scale and (2) modification of the scale growth mechanism from simultaneous countercurrent diffusion of aluminum and oxygen to predominant inward diffusion of oxygen, which generates less growth stress and thus prevents the formation of fast diffusion paths such as microcracks. The adhesion improvement of alumina scale formed on the Fe3Al-Y was attributed to the modification of alumina growth mechanism by the addition of Y to the Fe3Al alloy. The change of growth mechanism leads to the formation of pegs, decrease of the oxide growth stress, and decrease of voids formation, which enhances the adhesion of alumina scale to the Fe3Al alloy. The second study has focused on the corrosion of Fe3Al in the temperature range of 600--800°C in Cl2-Ar gas mixtures containing traces of oxygen as an impurity. Weight gain was observed during the corrosion of Fe3Al at 600°C in 0.25% Cl2-Ar, which is due to the formation of Fe2O3, while continuous

Pulsed laser deposition of epitaxial yttrium iron garnet films with low Gilbert damping and bulk-like magnetization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onbasli, M. C., E-mail: onbasli@mit.edu; Kim, D. H.; Ross, C. A.

2014-10-01

Yttrium iron garnet (YIG, Y {sub 3}Fe{sub 5}O{sub 12}) films have been epitaxially grown on Gadolinium Gallium Garnet (GGG, Gd{sub 3}Ga{sub 5}O{sub 12}) substrates with (100) orientation using pulsed laser deposition. The films were single-phase, epitaxial with the GGG substrate, and the root-mean-square surface roughness varied between 0.14 nm and 0.2 nm. Films with thicknesses ranging from 17 to 200 nm exhibited low coercivity (<2 Oe), near-bulk room temperature saturation moments (∼135 emu cm{sup −3}), in-plane easy axis, and damping parameters as low as 2.2 × 10{sup −4}. These high quality YIG thin films are useful in the investigation ofmore » the origins of novel magnetic phenomena and magnetization dynamics.« less

Root Cause Analysis of Gastroduodenal Ulceration After Yttrium-90 Radioembolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lam, Marnix G. E. H.; Banerjee, Subhas; Louie, John D.

IntroductionA root cause analysis was performed on the occurrence of gastroduodenal ulceration after hepatic radioembolization (RE). We aimed to identify the risk factors in the treated population and to determine the specific mechanism of nontarget RE in individual cases. Methods: The records of 247 consecutive patients treated with yttrium-90 RE for primary (n = 90) or metastatic (n = 157) liver cancer using either resin (n = 181) or glass (n = 66) microspheres were reviewed. All patients who developed a biopsy-proven microsphere-induced gastroduodenal ulcer were identified. Univariate and multivariate analyses were performed on baseline parameters and procedural data tomore » determine possible risk factors in the total population. Individual cases were analyzed to ascertain the specific cause, including identification of the culprit vessel(s) leading to extrahepatic deposition of the microspheres. Results: Eight patients (3.2 %) developed a gastroduodenal ulcer. Stasis during injection was the strongest independent risk factor (p = 0.004), followed by distal origin of the gastroduodenal artery (p = 0.004), young age (p = 0.040), and proximal injection of the microspheres (p = 0.043). Prolonged administrations, pain during administration, whole liver treatment, and use of resin microspheres also showed interrelated trends in multivariate analysis. Retrospective review of intraprocedural and postprocedural imaging showed a probable or possible culprit vessel, each a tiny complex collateral vessel, in seven patients. Conclusion: Proximal administrations and those resulting in stasis of flow presented increased risk for gastroduodenal ulceration. Patients who had undergone bevacizumab therapy were at high risk for developing stasis.« less

Water soluble two-photon fluorescent organic probes for long-term imaging of lysosomes in live cells and tumor spheroids.

PubMed

Kumari, Pratibha; Verma, Sanjay K; Mobin, Shaikh M

2018-01-11

The morphological alteration of lysosomes is a powerful indicator of various pathological disorders. In this regard, we have designed and synthesized a new water soluble fluorescent Schiff-base ligand (L-lyso) containing two hydroxyl groups. L-lyso exhibits excellent two-photon properties with tracking of lysosomes in live cells as well as in 3D tumor spheroids. Furthermore, it can label lysosomes for more than 3 days. Thus, L-lyso has an edge over the commercially available expensive LysoTracker probes and also over other reported probes in terms of its long-term imaging, water solubility and facile synthesis.

Spectroscopic study of trivalent praseodymium in barium yttrium fluoride

NASA Astrophysics Data System (ADS)

Bowlby, Brian Edward

1998-09-01

This work investigates the spectroscopic properties of trivalent praseodymium (Pr3+) in barium yttrium fluoride (BaY2F8). Two doping concentrations were studied: BaY2F8:Pr3+ (.3%) and BaY2F8:Pr3+ (1%). Absorption spectra were taken at 77K and 300K and these were then used to calculate the Judd-Ofelt coefficients for both samples. These coefficients were then used to calculate the theoretical lifetimes and radiative branching ratios for all manifolds. Continuous luminescence spectra and lifetime measurements were also performed, and from these, experimentally determined values for the branching ratio and lifetimes were determined. These were then compared to their theoretical counterparts. It was found that while the theory gave values that were qualitatively correct, the quantitative correlation between theory and experiment shows the complexity of the physical reality and the difficulty of synthesizing an encompassing theoretical model. Absorption spectra and continuous luminescence spectra were also used to determine the energy levels of all manifolds in both samples. A total of 59 energy levels in 11 manifolds were identified in the BaY2F8:Pr3+ (1%) sample, while 51 levels in 11 manifolds were identified in the BaY2F8:Pr3+ (.3%) sample. Finally, the effects of temperature on the line width and line position for several radiative transitions was studied. It was found that while most transitions exhibited the expected broadening and shifting towards longer wavelengths at higher temperatures (a 'red shift'), the transition from the 3P0 level to the 3H4 ground state showed a shift towards shorter wavelengths at higher temperature (a 'blue shift'). Again this highlights the complexity of the ion- host interaction.

Reduction of elevated plasma globotriaosylsphingosine in patients with classic Fabry disease following enzyme replacement therapy.

PubMed

van Breemen, Mariëlle J; Rombach, Saskia M; Dekker, Nick; Poorthuis, Ben J; Linthorst, Gabor E; Zwinderman, Aeilko H; Breunig, Frank; Wanner, Christoph; Aerts, Johannes M; Hollak, Carla E

2011-01-01

Fabry disease is treated by two-weekly infusions with α-galactosidase A, which is deficient in this X-linked globotriaosylceramide (Gb3) storage disorder. Elevated plasma globotriaosylsphingosine (lysoGb3) is a hallmark of classical Fabry disease. We investigated effects of enzyme replacement therapy (ERT) on plasma levels of lysoGb3 and Gb3 in patients with classical Fabry disease treated with agalsidase alfa at 0.2mg/kg, agalsidase beta at 0.2mg/kg or at 1.0mg/kg bodyweight. Each treatment regimen led to prominent reductions of plasma lysoGb3 in Fabry males within 3 months (P=0.0313), followed by relative stability later on. Many males developed antibodies against α-galactosidase A, particularly those treated with agalsidase beta. Patients with antibodies tended towards smaller correction in plasma lysoGb3 concentration, whereas treatment with high dose agalsidase beta allowed a reduction comparable to patients without antibodies. Pre-treatment plasma lysoGb3 concentrations of Fabry females were relatively low. In all females and with each treatment regimen, ERT gave reduction or stabilisation of plasma lysoGb3. Our investigation revealed that ERT of Fabry patients reduces plasma lysoGb3, regardless of the recombinant enzyme used. This finding shows that ERT can correct a characteristic biochemical abnormality in Fabry patients. Copyright © 2010 Elsevier B.V. All rights reserved.

Examination of Triacylglycerol Biosynthetic Pathways via De Novo Transcriptomic and Proteomic Analyses in an Unsequenced Microalga

DTIC Science & Technology

2011-10-17

analysis results. The components of the TAG biosynthetic pathway, including glycerol-3-phosphate acyl- transferase (GPAT), lyso- phosphatidic acid ...acyltransferase (LPAAT), phosphatidic acid phosphatase (PAP), lyso-phosphati- dylcholine acyltransferase (LPAT), and diacylglycerol acyltransfer- ase (DGAT...transfer to position one of G3P results in the formation of lyso- phosphatidic acid (LPA), in a reaction catalyzed by GPAT. Subsequent acyl transfer to

Microtensile bond strength of composite resin to human enamel prepared using erbium: Yttrium aluminum garnet laser.

PubMed

Delfino, Carina Sinclér; Souza-Zaroni, Wanessa Christine; Corona, Silmara Aparecida Milori; Palma-Dibb, Regina Guenka

2007-02-01

The Erbium: Yttrium Aluminum Garnet (YAG) laser used for preparation of cavity can alter the substrate and it could influence the bond strength of enamel. The aim of this in vitro study was to evaluate the influence of Er:YAG laser's energy using microtensile bond test. Three groups were obtained (cavity preparation) and each group was divided into two subgroups (adhesive system). After that the adhesive protocol was performed, sections with a cross-sectional area of 0.8 mm2 (+/-0.2 mm2) were obtained. The specimens were mounted in a universal testing machine (0.5 mm/min). Statistical analysis showed a decrease in bond strength for lased groups (p < 0.01) and when the total-etching adhesive system was used the laser 300 mJ subgroup showed higher bond strength compared to the laser 250 mJ (p < 0.01). It was concluded that the cavities prepared using laser appear less receptive to adhesive procedures than conventional bur-cut cavities. Copyright 2006 Wiley Periodicals, Inc.

Buffer-induced swelling and vesicle budding in binary lipid mixtures of dioleoylphosphatidylcholine:dioleoylphosphatidylethanolamine and dioleoylphosphatidylcholine:lysophosphatidylcholine using small-angle X-ray scattering and ³¹P static NMR.

PubMed

Barriga, Hanna M G; Bazin, Richard; Templer, Richard H; Law, Robert V; Ces, Oscar

2015-03-17

A large variety of data exists on lipid phase behavior; however, it is mostly in nonbuffered systems over nonbiological temperature ranges. We present biophysical data on lipid mixtures of dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylethanolamine (DOPE), and lysophosphatidylcholine (LysoPC) examining their behaviors in excess water and buffer systems over the temperature range 4-34 °C. These mixtures are commonly used to investigate the effects of spontaneous curvature on integral membrane proteins. Using small-angle X-ray scattering (SAXS) and (31)P NMR, we observed lamellar and vesicle phases, with the buffer causing an increase in the layer spacing. Increasing amounts of DOPE in a DOPC bilayer decreased the layer spacing of the mesophase, while the opposite trend was observed for increasing amounts of LysoPC. (31)P static NMR was used to analyze the DOPC:LysoPC samples to investigate the vesicle sizes present, with evidence of vesicle budding observed at LysoPC concentrations above 30 mol %. NMR line shapes were fitted using an adapted program accounting for the distortion of the lipids within the magnetic field. The distortion of the vesicle, because of magnetic susceptibility, varied with LysoPC content, and a discontinuity was found in both the water and buffer samples. Generally, the distortion increased with LysoPC content; however, at a ratio of DOPC:LysoPC 60:40, the sample showed a level of distortion of the vesicle similar to that of pure DOPC. This implies an increased flexibility in the membrane at this point. Commonly, the assumption is that for increasing LysoPC concentration there is a reduction in membrane tension, implying that estimations of membrane tension based on spontaneous curvature assumptions may not be accurate.

Densification of porous refractory substrates. [space shuttle orbiter tiles

NASA Technical Reports Server (NTRS)

Ecord, G. M.; Schomburg, C. (Inventor)

1982-01-01

A hydrolyzed tetraethyl orthosilicate is applied to the surface of a porous refractory substrate following which the substrate is heated to a temperature and for a period of time sufficient to bond the silica released from the tetraethyl orthosilicate to the substrate. The surface is thus densified and strengthened.

Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

NASA Astrophysics Data System (ADS)

Nassisi, Vincenzo; Delle Side, Domenico; Turco, Vito; Martina, Luigi

2018-01-01

In this work, we study surface modifications of AISI 420 stainless steel specimens in order to improve their surface properties. Oxidation resistance and surface micro-hardness were analyzed. Using an ion beam delivered by a Laser Ion Source (LIS) coupled to an electrostatic accelerator, we performed implantation of low energy yttrium ions on the samples. The ions experienced an acceleration passing through a gap whose ends had a potential difference of 60 kV. The gap was placed immediately before the samples surface. The LIS produced high ions fluxes per laser pulse, up to 3x1011 ions/cm2, resulting in a total implanted flux of 7x1015 ions/cm2. The samples were characterized before and after ion implantation using two analytical techniques. They were also thermally treated to investigate the oxide scale. The crystal phases were identified by an X-ray diffractometer, while the micro-hardness was assayed using the scratch test and a profilometer. The first analysis was applied to blank, implanted and thermally treated sample surface, while the latter was applied only to blank and implanted sample surfaces. We found a slight increase in the hardness values and an increase to oxygen resistance. The implantation technique we used has the advantages, with respect to conventional methods, to modify the samples at low temperature avoiding stray diffusion of ions inside the substrate bulk.

Sub-micrometer yttrium iron garnet LPE films with low ferromagnetic resonance losses

NASA Astrophysics Data System (ADS)

Dubs, Carsten; Surzhenko, Oleksii; Linke, Ralf; Danilewsky, Andreas; Brückner, Uwe; Dellith, Jan

2017-05-01

Using a liquid phase epitaxy (LPE) technique (1 1 1) yttrium iron garnet (YIG) films with thicknesses of  ≈100 nm and surface roughnesses as low as 0.3 nm have been grown on (1 1 1) gadolinium gallium garnet (GGG) substrates as a basic material for spin-wave propagation experiments in microstructured waveguides. The continuously strained films exhibit nearly perfect crystallinity without significant mosaicity and with effective lattice misfits of Δ {{a}\\bot}/{{a}s}≈ {{10}-4} and below. The film/substrate interface is extremely sharp without broad interdiffusion layer formation. All LPE films exhibit a nearly bulk-like saturation magnetization of (1800+/- 20 ) Gs and an ‘easy cone’ anisotropy type with extremely small in-plane coercive fields  <0.2 Oe. There is a rather weak in-plane magnetic anisotropy with a pronounced six-fold symmetry observed for the saturation field  <1.5 Oe. No significant out-of-plane anisotropy is observed, but a weak dependence of the effective magnetization on the lattice misfit is detected. The narrowest ferromagnetic resonance linewidth is determined to be 1.4 Oe @ 6.5 GHz which is the lowest value reported so far for YIG films of 100 nm thicknesses and below. The Gilbert damping coefficient for investigated LPE films is estimated to be close to 1× {{10}-4} .

[Structure and properties of colored dental tetragonal zirconia stabilized by yttrium ceramics].

PubMed

Yi, Yuan-fu; Wang, Chen; Wen, Ning; Lin, Yong-zhao; Tian, Jie-mo

2009-10-01

To investigate the structure, mechanical and low temperature aging properties of colored dental zirconia ceramics. 5 graded colored dental zirconia ceramics were made by adding colorants and their combinations into a 3Y-TZP (tetragonal zirconia stabilized by 3mol% yttrium) powder, the green body were compacted at 200 MPa, pre-sinter at 1,050 degrees C and maintained for 2 h, then densely sintered at 1,500 degrees C for 2 h. Specimens were cut from each of the 5 graded colored blocks. Physical, mechanical properties as well as chemical stability were tested, microstructure were observed, crystalline phase were identified by X-ray diffraction (XRD), aging properties were assessed by measurement of the relative content of monoclinic phase and bending strength testing. The overall density of colored zirconia ceramics was over 99.7%, linear shrinkage was about 20%, while thermal expansion coefficient was about 11 x 10(-6) x degrees C(-1), the crystalline phase was tetragonal, bending strength was over 900 MPa which was slightly lowered than that of the uncolored zirconia, fracture toughness was slightly higher. Good chemical stability in acetic acid was observed. After aging treatment, tetragonal-to-monoclinic phase transformation was detected up to 40%, while bending strength was not significantly degraded. The results showed that colored 3Y-TZP ceramics presented good mechanical properties even after aging treatments, and was suitable for dental clinical use.

Activating Photodynamic Therapy in vitro with Cerenkov Radiation Generated from Yttrium-90

PubMed Central

Hartl, Brad A.; Hirschberg, Henry; Marcu, Laura; Cherry, Simon R.

2017-01-01

The translation of photodynamic therapy (PDT) to the clinical setting has primarily been limited to easily accessible and/or superficial diseases, for which traditional light delivery can be performed noninvasively. Cerenkov radiation, as generated from medically relevant radionuclides, has been suggested as a means to deliver light to deeper tissues noninvasively to overcome this depth limitation. This article investigates the utility of Cerenkov radiation, as generated from the radionuclide yttrium-90, for activating the PDT process using clinically approved aminolevulinic acid at 1.0 mm and also the more efficient porphyrin-based photosensitizer mesotetraphenylporphine with two sulfonate groups on adjacent phenyl rings (TPPS2a) at 1.2 μM. Experiments were conducted with monolayer cultured glioma and breast tumor cell lines. Although aminolevulinic acid proved to be ineffective for generating a therapeutic effect at all but the highest activity levels, TPPS2a produced at least a 20% therapeutic effect at activities ranging from 6 to 60 μCi/well for the C6 glioma cell line. Importantly, these results demonstrate for the first time, to our knowledge, that Cerenkov radiation generated from a radionuclide can be used to activate PDT using clinically relevant photosensitizers. These results therefore provide evidence that it may be possible to generate a phototherapeutic effect in vivo using Cerenkov radiation and clinically relevant photosensitizers. PMID:27481495

A Submillimeter Resolution PET Prototype Evaluated With an 18F Inkjet Printed Phantom

NASA Astrophysics Data System (ADS)

Schneider, Florian R.; Hohberg, Melanie; Mann, Alexander B.; Paul, Stephan; Ziegler, Sibylle I.

2015-10-01

This work presents a submillimeter resolution PET (Positron Emission Tomography) scanner prototype based on SiPM/MPPC arrays (Silicon Photomultiplier/Multi Pixel Photon Counter). Onto each active area a 1 ×1 ×20 mm3 LYSO (Lutetium-Yttrium-Oxyorthosilicate) scintillator crystal is coupled one-to-one. Two detector modules facing each other in a distance of 10.0 cm have been set up with in total 64 channels that are digitized by SADCs (Sampling Analog to Digital Converters) with 80 MHz, 10 bit resolution and FPGA (Field Programmable Gate Array) based extraction of energy and time information. Since standard phantoms are not sufficient for testing submillimeter resolution at which positron range is an issue, a 18F inkjet printed phantom has been used to explore the limit in spatial resolution. The phantom could be successfully reconstructed with an iterative MLEM (Maximum Likelihood Expectation Maximization) and an analytically calculated system matrix based on the DRF (Detector Response Function) model. The system yields a coincidence time resolution of 4.8 ns FWHM, an energy resolution of 20%-30% FWHM and a spatial resolution of 0.8 mm.

Uranium, yttrium, and rare earth elements accumulation during the Cretaceous anoxic events in carbonaceous rocks in the Pacific Ocean

NASA Astrophysics Data System (ADS)

Savelyeva, Olga; Philosofova, Tatyana; Bergal-Kuvikas, Olga; Savelyeva, Svetlana

2017-04-01

We have studied the carbonate-siliceous section of paleooceanic Albian-Cenomanian deposits on the Kamchatsky Mys peninsula (Eastern Kamchatka, Russia) [1].The section is represented by a rhythmic alternation of planktonic limestones and jaspers, accumulated in the open ocean environment. The rhythmicity can be attributed to climate variations that reflect a fluctuation of astronomical parameters (Milankovitch cycles) [2, 3].The section contains two beds enriched in organic carbon, corresponding to the two oceanic anoxic events - MCE and OAE2 [3]. The maximum content of organic matter in those beds reaches 68%. Our geochemical studies revealed an enrichment of the carbonaceous rocks in some major and trace elements including PGE, in comparison with the surrounding limestone and jasper [4].The accumulation of the ore elements in carbonaceous beds is caused by euxinic conditions during sedimentation.The content of uranium, yttrium, and rare earth elements in carbonaceous rocks is up to 60, 142 and 312 ppm respectively. Phosphate grains (bone detritus) with microinclusions of yttrium and uranium minerals were revealed in the carbonaceous rocks using the scanning electron microscope. These data prove the hypothesis of the sorbtion of U and Y by phosphate detritus from seawater. Microprobe analysis also showed an increased content of Cu, Zn, V in some pyrite framboids, which indicates that these elements are fixed in rocks by Fe-sulphide phase or organic matter under euxinic conditions. Our research may bring us closer to understanding the mechanism of syngenetic accumulation of metals in the black shales. This work was supported by the RFBR (No. 16-05-00546). [1] Palechek, T.N., Savelyev, D.P., Savelyeva, O.L. (2010) Stratigraphy and Geological Correlation 18, (1) 63-82. [2] Savelyeva, O.L. (2010). Vestnik Kraunts. Nauki o zemle 1 (15), 45-55 (in Russian). [3] Savelyev, D.P., Savelyeva, O.L., Palechek, T.N., Pokrovsky, B.G. (2012) Geophysical Research Abstracts, 14, EGU

Prospective study to determine early hypertrophy of the contra-lateral liver lobe after unilobar, Yttrium-90, selective internal radiation therapy in patients with hepatocellular carcinoma.

PubMed

Teo, Jin Yao; Allen, John Carson; Ng, David Chee Eng; Abdul Latiff, Julianah Bee; Choo, Su Pin; Tai, David Wai-Meng; Low, Albert Su Chong; Cheah, Foong Koon; Chang, Jason Pik Eu; Kam, Juinn Huar; Lee, Victor T W; Chung, Alexander Yaw Fui; Chan, Chung Yip; Chow, Pierce Kah Hoe; Goh, Brian K P

2018-05-01

Liver resection is a major curative option in patients presenting with hepatocellular carcinoma. An inadequate functional liver remnant is a major limiting factor precluding liver resection. In recent years, hypertrophy of the functional liver remnant after selective internal radiation therapy hypertrophy has been observed, but the degree of hypertrophy in the early postselective internal radiation therapy period has not been well studied. We conducted a prospective study on patients undergoing unilobar, Yttrium-90 selective internal radiation therapy for hepatocellular carcinoma to evaluate early hypertrophy at 4-6 weeks and 8-12 weeks after selective internal radiation therapy. In the study, 24 eligible patients were recruited and had serial volumetric measurements performed. The median age was 66 years (38-75 years). All patients were either Child-Pugh Class A or B, and 6/24 patients had documented, clinically relevant portal hypertension; 15 of the 24 patients were hepatitis B positive. At 4-6 weeks, modest hypertrophy was seen (median 3%; range -12 to 42%) and this increased at 8-12 weeks (median 9%; range -12 to 179%). No preprocedural factors predictive of hypertrophy were identified. Hypertrophy of the functional liver remnant after selective internal radiation therapy with Yttrium-90 occurred in a subset of patients but was modest and unpredictable in the early stages. Selective internal radiation therapy cannot be recommended as a standard treatment modality to induce early hypertrophy for patients with hepatocellular carcinoma. (Surgery 2017;160:XXX-XXX.). Copyright © 2017 Elsevier Inc. All rights reserved.

Reflection and Transmission Coefficient of Yttrium Iron Garnet Filled Polyvinylidene Fluoride Composite Using Rectangular Waveguide at Microwave Frequencies

PubMed Central

Soleimani, Hassan; Abbas, Zulkifly; Yahya, Noorhana; Shameli, Kamyar; Soleimani, Hojjatollah; Shabanzadeh, Parvaneh

2012-01-01

The sol-gel method was carried out to synthesize nanosized Yttrium Iron Garnet (YIG). The nanomaterials with ferrite structure were heat-treated at different temperatures from 500 to 1000 °C. The phase identification, morphology and functional groups of the prepared samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. The YIG ferrite nanopowder was composited with polyvinylidene fluoride (PVDF) by a solution casting method. The magnitudes of reflection and transmission coefficients of PVDF/YIG containing 6, 10 and 13% YIG, respectively, were measured using rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) in X-band frequencies. The results indicate that the presence of YIG in polymer composites causes an increase in reflection coefficient and decrease in transmission coefficient of the polymer. PMID:22942718

Study of the response of a lithium yttrium borate scintillator based neutron rem counter by Monte Carlo radiation transport simulations

NASA Astrophysics Data System (ADS)

Sunil, C.; Tyagi, Mohit; Biju, K.; Shanbhag, A. A.; Bandyopadhyay, T.

2015-12-01

The scarcity and the high cost of 3He has spurred the use of various detectors for neutron monitoring. A new lithium yttrium borate scintillator developed in BARC has been studied for its use in a neutron rem counter. The scintillator is made of natural lithium and boron, and the yield of reaction products that will generate a signal in a real time detector has been studied by FLUKA Monte Carlo radiation transport code. A 2 cm lead introduced to enhance the gamma rejection shows no appreciable change in the shape of the fluence response or in the yield of reaction products. The fluence response when normalized at the average energy of an Am-Be neutron source shows promise of being used as rem counter.

Polarization selection rules and optical transitions in terbium activated yttrium tantalate phosphor under x-ray, vacuum-ultraviolet, and ultraviolet excitations.

PubMed

Nazarov, Mihail; Tsukerblat, Boris; Byeon, Clare Chisu; Arellano, Ivan; Popovici, Elisabeth-Jeanne; Noh, Do Young

2009-01-01

The terbium-activated yttrium tantalite (YTaO(4):Tb(3+)) phosphor is of great interest due to the interesting spectroscopic properties of rare earth ions in crystals and also practical use in x-ray imaging. Using the group-theoretical approach, we analyze the selection rules for the transition between Stark components of Tb(3+) in symmetry of the actual crystal field and the polarization for the allowed transitions. The luminescence upon UV, vacuum-ultraviolet (VUV), and x-ray excitation is presented and discussed. The YTaO(4):Tb(3+) phosphors are found to be efficient VUV-excited luminescent materials that could be used not only in x-ray intensifying screens, but also in mercury-free fluorescent lamps or plasma display panels.

A randomized controlled trial of peeling and aspiration of Elschnig pearls and neodymium: yttrium-aluminium-garnet laser capsulotomy.

PubMed

Bhargava, Rahul; Kumar, Prachi; Sharma, Shiv Kumar; Kaur, Avinash

2015-01-01

To compare surgical peeling and aspiration and neodymium yttrium garnet laser capsulotomy for pearl form of posterior capsule opacification (PCO). A prospective, randomized, double blind, study was done at Rotary Eye Hospital, Maranda, Palampur, India, Santosh Medical College Hospital, Ghaziabad, India and Laser Eye Clinic, Noida India. Consecutive patients with pearl form of PCO following surgery, phacoemulsification, manual small incision cataract surgery and conventional extracapsular cataract extraction (ECCE) for age related cataract, were randomized to have peeling and aspiration or neodymium yttrium garnet laser capsulotomy. Corrected distance visual acuity (CDVA), intra-operative and post-operative complications were compared. A total of 634 patients participated in the study, and 314 (49.5%) patients were randomized to surgical peeling and aspiration group and 320 (50.5%) to the Nd:YAG laser group. The mean pre-procedural logMAR CDVA in peeling and neodymium: yttrium-aluminium-garnet (Nd:YAG) laser group was 0.80±0.25 and 0.86±0.22, respectively. The mean final CDVA in peeling group (0.22±0.23) was comparable to Nd:YAG group (0.24±0.28; t test, P=0.240). There was a significant improvement in vision after both the procedures (P<0.001). A slightly higher percentage of patients in Nd:YAG laser group (283/88.3%) than in peeling group (262/83.4%) had a CDVA of 0.5 (20/63) or better at 9mo (P<0.001). On the contrary, patients having CDVA worse than 1.00 (20/200) was also significantly higher in Nd:YAG laser group as compared to peeling group (25/7.7% vs 15/4.7%, respectively). On application of ANCOVA, there was less than 0.001% risk that PCO thickness and total laser energy had no effect on rate of complications in Nd:YAG laser group and less than 0.001 % risk that PCO thickness had no effect on complications in peeling group respectively. Sum of square analysis suggests that in the Nd:YAG laser group, thick PCO had a stronger impact on complications

A randomized controlled trial of peeling and aspiration of Elschnig pearls and neodymium: yttrium-aluminium-garnet laser capsulotomy

PubMed Central

Bhargava, Rahul; Kumar, Prachi; Sharma, Shiv Kumar; Kaur, Avinash

2015-01-01

AIM To compare surgical peeling and aspiration and neodymium yttrium garnet laser capsulotomy for pearl form of posterior capsule opacification (PCO). METHODS A prospective, randomized, double blind, study was done at Rotary Eye Hospital, Maranda, Palampur, India, Santosh Medical College Hospital, Ghaziabad, India and Laser Eye Clinic, Noida India. Consecutive patients with pearl form of PCO following surgery, phacoemulsification, manual small incision cataract surgery and conventional extracapsular cataract extraction (ECCE) for age related cataract, were randomized to have peeling and aspiration or neodymium yttrium garnet laser capsulotomy. Corrected distance visual acuity (CDVA), intra-operative and post-operative complications were compared. RESULTS A total of 634 patients participated in the study, and 314 (49.5%) patients were randomized to surgical peeling and aspiration group and 320 (50.5%) to the Nd:YAG laser group. The mean pre-procedural logMAR CDVA in peeling and neodymium: yttrium-aluminium-garnet (Nd:YAG) laser group was 0.80±0.25 and 0.86±0.22, respectively. The mean final CDVA in peeling group (0.22±0.23) was comparable to Nd:YAG group (0.24±0.28; t test, P=0.240). There was a significant improvement in vision after both the procedures (P<0.001). A slightly higher percentage of patients in Nd:YAG laser group (283/88.3%) than in peeling group (262/83.4%) had a CDVA of 0.5 (20/63) or better at 9mo (P<0.001). On the contrary, patients having CDVA worse than 1.00 (20/200) was also significantly higher in Nd:YAG laser group as compared to peeling group (25/7.7% vs 15/4.7%, respectively). On application of ANCOVA, there was less than 0.001% risk that PCO thickness and total laser energy had no effect on rate of complications in Nd:YAG laser group and less than 0.001 % risk that PCO thickness had no effect on complications in peeling group respectively. Sum of square analysis suggests that in the Nd:YAG laser group, thick PCO had a stronger impact on

EMBOLIZATION OF DOG PROSTATES WITH YTTRIUM-90 MICROSPHERES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene, W.M.

1963-10-01

Experiments exploring means for the protection of adjacent normal tissue while delivering a destructive dose of radiation to malignant tissue were conducted. By injection of radioactive ceramic spheres or particles, too large to pass through capillaries or arteriovenous shunts, relatively high doses of radiation can be distributed homogeneously to a circumscribed area. Attempts were made to determine the uniformity of distribution and the radiation effect of varying doses of spheres injected into the arterial supply of the dog prostate. Nonradioactive and radioactive ceramic microspheres of 60 mu dia were used since this size exceeds the diameter of capillaries and arteriovenousmore » shunts. Yttrium-90 microspheres of varying radioactivity were used. Doses injected into right and left hypogastric arteries varied from 0.69 to 28.4 mc/side (92-1260 mc/ g prostate). Homogeneous distribution of radioactivity within the prostate was demonstrated by autoradiography. Distribution to some other organs (rectum, penis, and bladder) occurred because arterial supply to these structures was not isolated and occluded. The amount of radioactivity found in the lungs suggested more venous drainage in some cases than seemed apparent, and because of the infarctions of pelvic organs may have leaked radioactive spheres into the venous circuit. In 6 of the 8 dogs which died prematurely (2 to 7 days after surgery) obvious infarction of the prostate and in some other pelvic structures had occurred. That the radioactivity contributed to the infarction is suggested by the results in the dogs which received large doses of radioactivity (18.9 and 28.4 mc per side) in minimal amounts of spheres (100to 150 mg per side). The intensely concentrated radioactivity within the arteriolar lumens may have caused vasculitis and subsequent thrombosis. Although homogeneous destruction of the prostate gland occurred, the effect of a given dose ranged unpredictably through three groups: no apparent

Cataracts induced by neodymium-yttrium-aluminium-garnet laser lysis of vitreous floaters.

PubMed

Koo, Ellen H; Haddock, Luis J; Bhardwaj, Namita; Fortun, Jorge A

2017-06-01

Neodymium-yttrium-aluminium-garnet (Nd:YAG) laser vitreolysis has been proposed as a treatment modality for symptomatic vitreous floaters. The purpose of this paper is to report two cases of cataracts associated with posterior capsular compromise, induced by Nd:YAG laser vitreolysis for symptomatic vitreous floaters. Case series. Two patients who underwent ND:YAG laser vitreolysis for symptomatic floaters, presented with decline in visual acuity in the treated eye after the laser procedure. At the slit-lamp biomicroscope, each patient was found to have a posterior subcapsular cataract in the treated eye, with obvious loss of integrity of the posterior capsule. These two patients underwent cataract extraction by the same surgeon via phacoemulsification. Both eyes were found to have a defect in the posterior capsule intraoperatively. In both cases, a three-piece acrylic intraocular lens implant was placed in the sulcus, achieving optic capture. The best-corrected visual acuity (BCVA) was 20/20 in both patients, at 1 month following the surgery. At 2 months, one patient had a BCVA of 20/15. The second patient maintained a BCVA of 20/20 at 3 months. Secondary cataract formation accompanied by loss of integrity of the posterior capsule is a potential complication of Nd:YAG laser vitreolysis for symptomatic floaters. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Marine phosphorites as potential resources for heavy rare earth elements and yttrium

USGS Publications Warehouse

Hein, James; Koschinsky, Andrea; Mikesell, Mariah; Mizell, Kira; Glenn, Craig R.; Wood, Ray

2016-01-01

Marine phosphorites are known to concentrate rare earth elements and yttrium (REY) during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deposits found in the global ocean host REY concentrations of high enough grade to be of economic interest. This paper addresses continental-margin (CM) and open-ocean seamount phosphorites. All 75 samples analyzed are composed predominantly of carbonate fluorapatite and minor detrital and authigenic minerals. CM phosphorites have low total REY contents (mean 161 ppm) and high heavy REY (HREY) complements (mean 49%), while seamount phosphorites have 4–6 times higher individual REY contents (except for Ce, which is subequal; mean ΣREY 727 ppm), and very high HREY complements (mean 60%). The predominant causes of higher concentrations and larger HREY complements in seamount phosphorites compared to CM phosphorites are age, changes in seawater REY concentrations over time, water depth of formation, changes in pH and complexing ligands, and differences in organic carbon content in the depositional environments. Potential ore deposits with high HREY complements, like the marine phosphorites analyzed here, could help supply the HREY needed for high-tech and green-tech applications without creating an oversupply of the LREY.

Separation and preconcentration of the rare-earth elements and yttrium from geological materials by ion-exchange and sequential acid elution

USGS Publications Warehouse

Crock, J.G.; Lichte, F.E.; Riddle, G.O.; Beech, C.L.

1986-01-01

The abundance of rare-earth elements (REE) and yttrium in geological materials is generally low, and most samples contain elements that interfere in the determination of the REE and Y, so a separation and/or preconcentration step is often necessary. This is often achieved by ion-exchange chromatography with either nitric or hydrochloric acid. It is advantageous, however, to use both acids sequentially. The final solution thus obtained contains only the REE and Y, with minor amounts of Al, Ba, Ca, Sc, Sr and Ti. Elements that potentially interfere, such as Be, Co, Cr, Fe, Mn, Th, U, V and Zr, are virtually eliminated. Inductively-coupled argon plasma atomic-emission spectroscopy can then be used for a final precise and accurate measurement. The method can also be used with other instrumental methods of analysis. ?? 1986.

Commentary: Is There Clinical Benefit From Using a Diode or Neodymium:Yttrium-Aluminum-Garnet Laser in the Treatment of Periodontitis?

PubMed

Cobb, Charles M

2016-10-01

Despite a quarter of a century of laser research, there is a persistent debate regarding the efficacy of dental lasers in the treatment of periodontitis or periodontal maintenance therapy. There are many claims and much hyperbole surrounding the use of lasers, either as a monotherapy or adjunctive to scaling and root planing, to treat periodontitis. There is little evidence that using a diode or neodymium:yttrium-aluminum-garnet laser adds clinical value over and above conventional non-surgical or surgical periodontal treatment. There is a significant need for better designed human clinical trials. Data from such trials should be analyzed according to initial probing depth and characteristics of the treated sites, such as non-molar, molar flat surfaces, and molar furcations, and evaluated for long-term post-treatment results.

Study of yttrium 4-nitrocinnamate to promote surface interactions with AS1020 steel

NASA Astrophysics Data System (ADS)

Hien, P. V.; Vu, N. S. H.; Thu, V. T. H.; Somers, A.; Nam, N. D.

2017-08-01

Yttrium 4-nitrocinnamate (Y(4-NO2Cin)3) was added to an aqueous chloride solution and studied as a possible corrosion inhibition system. Electrochemical techniques and surface analysis have been powerful tools to better understand the corrosion and inhibition processes of mild steel in 0.01 M NaCl solution. A combination of scanning electron microscopy (SEM), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), Potentiodynamic polarization (PD), electrochemical impedance spectroscopy (EIS) and wire beam electrode (WBE) techniques was found to be useful in the characterization of this system. The result indicated that Y(4-NO2Cin)3 is able to effectively inhibit corrosion at a low concentration of 0.45 mM. Surface analysis clearly shows that the surface of steel coupons exposed to Y(4-NO2Cin)3 solution remained uniform and smooth, whereas the surface of steel coupons exposed to solution without inhibitor addition was severely corroded. The results suggest that Y(4-NO2Cin)3 behaves as a mixed inhibitor and mitigates corrosion by promoting random distribution of minor anodes. These are attributed to the formation of metal species bonding to the 4-nitrocinnamate component and hydrolysis of the Y(4-NO2Cin)3 to form oxide/hydroxides as a protective film layer.

Optimization of yttrium-90 PET for simultaneous PET/MR imaging: A phantom study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eldib, Mootaz

2016-08-15

Purpose: Positron emission tomography (PET) imaging of yttrium-90 in the liver post radioembolization has been shown useful for personalized dosimetry calculations and evaluation of extrahepatic deposition. The purpose of this study was to quantify the benefits of several MR-based data correction approaches offered by using a combined PET/MR system to improve Y-90 PET imaging. In particular, the feasibility of motion and partial volume corrections were investigated in a controlled phantom study. Methods: The ACR phantom was filled with an initial concentration of 8 GBq of Y-90 solution resulting in a contrast of 10:1 between the hot cylinders and the background.more » Y-90 PET motion correction through motion estimates from MR navigators was evaluated by using a custom-built motion stage that simulated realistic amplitudes of respiration-induced liver motion. Finally, the feasibility of an MR-based partial volume correction method was evaluated using a wavelet decomposition approach. Results: Motion resulted in a large (∼40%) loss of contrast recovery for the 8 mm cylinder in the phantom, but was corrected for after MR-based motion correction was applied. Partial volume correction improved contrast recovery by 13% for the 8 mm cylinder. Conclusions: MR-based data correction improves Y-90 PET imaging on simultaneous PET/MR systems. Assessment of these methods must be studied further in the clinical setting.« less

Improved hydrogen absorption and desorption kinetics of magnesium-based alloy via addition of yttrium

NASA Astrophysics Data System (ADS)

Yang, Tai; Li, Qiang; Liu, Ning; Liang, Chunyong; Yin, Fuxing; Zhang, Yanghuan

2018-02-01

Yttrium (Y) is selected to modify the microstructure of magnesium (Mg) to improve the hydrogen storage performance. Thereby, binary alloys with the nominal compositions of Mg24Yx (x = 1-5) are fabricated by inexpensive casting technique. Their microstructure and phase transformation during hydriding and dehydriding process are characterized by using X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy analysis. The isothermal hydrogen absorption and desorption kinetics are also measured by a Sievert's-type apparatus at various temperatures. Typical multiphase structures of binary alloy can be clearly observed. All of these alloys can reversibly absorb and desorb large amount of hydrogen at proper temperatures. The addition of Y markedly promotes the hydrogen absorption kinetics. However, it results in a reduction of reversible hydrogen storage capacity. A maximum value of dehydrogenation rate is observed with the increase of Y content. The Mg24Y3 alloy has the optimal desorption kinetic performance, and it can desorb about 5.4 wt% of hydrogen at 380 °C within 12 min. Combining Johnson-Mehl-Avrami kinetic model and Arrhenius equation, the dehydrogenation activation energy of the alloys are evaluated. The Mg24Y3 alloy also has the lowest dehydrogenation activation energy (119 kJ mol-1).

Feasibility assessment of yttrium-90 liver radioembolization imaging using amplitude-based gated PET/CT

PubMed Central

Acuff, Shelley N.; Neveu, Melissa L.; Syed, Mumtaz; Kaman, Austin D.; Fu, Yitong

2018-01-01

Purpose The usage of PET/computed tomography (CT) to monitor hepatocellular carcinoma patients following yttrium-90 (90Y) radioembolization has increased. Respiratory motion causes liver movement, which can be corrected using gating techniques at the expense of added noise. This work examines the use of amplitude-based gating on 90Y-PET/CT and its potential impact on diagnostic integrity. Patients and methods Patients were imaged using PET/CT following 90Y radioembolization. A respiratory band was used to collect respiratory cycle data. Patient data were processed as both standard and motion-corrected images. Regions of interest were drawn and compared using three methods. Activity concentrations were calculated and converted into dose estimates using previously determined and published scaling factors. Diagnostic assessments were performed using a binary scale created from published 90Y-PET/CT image interpretation guidelines. Results Estimates of radiation dose were increased (P<0.05) when using amplitude-gating methods with 90Y PET/CT imaging. Motion-corrected images show increased noise, but the diagnostic determination of success, using the Kao criteria, did not change between static and motion-corrected data. Conclusion Amplitude-gated PET/CT following 90Y radioembolization is feasible and may improve 90Y dose estimates while maintaining diagnostic assessment integrity. PMID:29351124

Yttrium aluminium garnet under pressure: Structural, elastic, and vibrational properties from ab initio studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monteseguro, V.; Rodríguez-Hernández, P.; Muñoz, A., E-mail: amunoz@ull.es

The structural, elastic, and vibrational properties of yttrium aluminum garnet Y{sub 3}Al{sub 5}O{sub 12} are studied under high pressure by ab initio calculations in the framework of the density functional theory. The calculated ground state properties are in good agreement with the available experimental data. Pressure dependences of bond length and bulk moduli of the constituent polyhedra are reported. The evolution of the elastic constants and the major elastic properties, Young and shear modulus, Poisson's ratios, and Zener anisotropy ratio, are described. The mechanical stability is analyzed, on the light of “Born generalized stability criteria,” showing that the garnet ismore » mechanically unstable above 116 GPa. Symmetries, frequencies, and pressure coefficients of the Raman-active modes are discussed on the basis of the calculated total and partial phonon density of states, which reflect the dynamical contribution of each atom. The relations between the phonon modes of Y{sub 3}Al{sub 5}O{sub 12} and the internal and external molecular modes of the different polyhedra are discussed. Infrared-active modes, as well as the silent modes, and their pressure dependence are also investigated. No dynamical instabilities were found below 116 GPa.« less

High-pressure synthesis of predicted oxynitride perovskite: Yttrium Silicon Oxynitride (YSiO2N)

NASA Astrophysics Data System (ADS)

Ahart, Muhtar; Somayazulu, M.; Vadapoo, Rajasekarakumar; Cohen, R. E.

We synthesized the previously predicted polar oxynitride perovskite in a diamond anvil cell with laser heating. YSiO2N was predicted to have the polar P4mm structure with an effective spontaneous polarization of 130 μC/cm2. A mixture of Yttrium nitride (YN) and amorphous Silicon dioxide (SiO2) were loaded into a diamond anvil cell and laser heated at or above 1200 C at 12 GPa. The run products were investigated by x-ray diffraction, Raman spectroscopy, and second harmonic generation, for their phase and structural properties. The x-ray diffraction pattern (a = 3.235 Å, c = 4.485 Å) shows the phase formation of YSiO2N and matches with the diffraction pattern derived from the first-principle predicted lattice parameters. However, minor unknown peaks are on the diffraction pattern indicating of the co-existence of other unknown phases. Further study of Raman spectroscopy observes the theoretically predicted modes, and second harmonic generation shows strong non-linear optical signal, which confirms the polar properties of YSiO2N. This work is supported by ONR Grants N00014-12-1-1038 and N00014-14-1-0561, by the ERC Advanced Grant ToMCaT.

Yttrium-90 -- current status, expected availability and applications of a high beta energy emitter.

PubMed

Montaña, R Leyva; González, I Hernández; Ramirez, A Alberti; Garaboldi, L; Chinol, M

2012-07-01

Yttrium-90 ((90)Y, T(1/2) 64.14 h) is a key example of a high beta energy-emitting radionuclide which is available from the strontium-90 ((90)Sr)/(90)Y radionuclide generator system. Clinical uses of (90)Y-labeled radiopharmaceutical agents have been pursued for many years and many applications have proven to be clinical effective. These most notably include the application of 90Y-labeled antibodies for a variety of applications such as for effective treatment of non-Hodgkin's lymphoma. One of the major advantages for use of (90)Y is ready availability from the very long-lived (90)Sr parent (T(1/2) 28.78 y). Because of the importance of maintaining generator performance and minimizing parent breakthrough, this paper describes development, use and quality control of both high capacity cation adsorption-type and electrochemical generator systems. In addition, the preparation and targeting to tumors in mice of DOTA-conjugated Nimotuzamab (h-R3) antibody which recognizes the external domain of the EPFR antibody radiolabeled with (90)Y obtained from the electrochemical generator is also described. As a key example for clinical applications of (90)Y, the use of (90)Y-labeled biotin for intra-operative pre-targeting for radionuclide therapy (IART®) of breast cancer is also described.

Variations in the GLA gene correlate with globotriaosylceramide and globotriaosylsphingosine analog levels in urine and plasma

PubMed Central

Ferreira, Susana; Auray-Blais, Christiane; Boutin, Michel; Lavoie, Pamela; Nunes, José Pedro; Martins, Elisabete; Garman, Scott; Oliveira, João Paulo

2016-01-01

Recent data have shown that lyso-Gb3, the deacylated derivative of globotriaosylceramide (Gb3), is possibly involved in the pathogenesis of Fabry disease (FD) and might be a clinically useful biomarker of its metabolic load. To test this hypothesis, we assayed Gb3 and lyso-Gb3 and related analogs in plasma and/or urine samples of 12 clinically well-characterized subjects carrying several different GLA variant alleles associated with a wide range of residual α-galactosidase A activities. Urinary Gb3 was measured by HPLC–MS/MS; plasma and urinary lyso-Gb3 and related analogs were measured by UPLC–MS/MS. Individual profiles of Gb3 and lyso-Gb3 and related analogs closely correlated with the phenotypic data for each subject, discerning the classical FD patient from the two patients carrying cardiac variants as well as these from all the others without FD. The lyso-Gb3 analog at m/z 836 was found at increased levels only in patients manifesting clinically severe heart disease, irrespective of the pathogenicity of the GLA variant they carried. This finding suggests that this lyso-Gb3 analog might be an earlier biomarker of progressive heart disease, non-specific of the FD cardiomyopathy. The possibility that urinary Gb3 is a specific marker of kidney involvement in FD deserves further study. PMID:26070511

Radioembolization of Symptomatic, Unresectable Neuroendocrine Hepatic Metastases Using Yttrium-90 Microspheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paprottka, Philipp M., E-mail: philipp.paprottka@med.uni-muenchen.de; Hoffmann, Ralf-T.; Haug, Alexander

2012-04-15

Purpose: To evaluate safety, efficacy, and symptom-control of radioembolization in patients with unresectable liver metastases from neuroendocrine tumors (NETLMs). Materials and Methods: Forty-two patients (mean age of 62 years) with treatment-refractory NETLMs underwent radioembolization using yttrium-90 ({sup 90}Y) resin microspheres. Posttreatment tumor response was assessed by cross-sectional imaging using the Response Evaluation Criteria in Solid Tumors (RECIST) and tumor-marker levels. Laboratory and clinical toxicities and clinical symptoms were monitored. Results: The median activity delivered was 1.63 GBq (range 0.63-2.36). Imaging follow-up using RECIST at 3-month follow-up demonstrated partial response, stable disease, and progressive disease in 22.5, 75.0, and 2.5% ofmore » patients, respectively. In 97.5% of patients, the liver lesions appeared hypovascular or partially necrotic. The mean follow-up was 16.2 months with 40 patients (95.2%) remaining alive. The median decrease in tumor-marker levels at 3 months was 54.8% (chromogranin A) and 37.3% (serotonin), respectively. There were no acute or delayed toxicities greater than grade 2 according to Common Terminology Criteria for Adverse Events [CTCAE (v3.0)]. No radiation-induced liver disease was noted. Improvement of clinical symptoms 3 months after treatment was observed in 36 of 38 symptomatic patients. Conclusion: Radioembolization with {sup 90}Y-microspheres is a safe and effective treatment option in patients with otherwise treatment-refractory NETLMs. Antitumoral effect is supported by good local tumor control, decreased tumor-marker levels, and improved clinical symptoms. Further investigation is warranted to define the role of radioembolization in the treatment paradigm for NETLMs.« less

Investigation of the unidirectional spin heat conveyer effect in a 200 nm thin Yttrium Iron Garnet film

NASA Astrophysics Data System (ADS)

Wid, Olga; Bauer, Jan; Müller, Alexander; Breitenstein, Otwin; Parkin, Stuart S. P.; Schmidt, Georg

2016-06-01

We have investigated the unidirectional spin wave heat conveyer effect in sub-micron thick yttrium iron garnet (YIG) films using lock-in thermography (LIT). Although the effect is small in thin layers this technique allows us to observe asymmetric heat transport by magnons which leads to asymmetric temperature profiles differing by several mK on both sides of the exciting antenna, respectively. Comparison of Damon-Eshbach and backward volume modes shows that the unidirectional heat flow is indeed due to non-reciprocal spin-waves. Because of the finite linewidth, small asymmetries can still be observed when only the uniform mode of ferromagnetic resonance is excited. The latter is of extreme importance for example when measuring the inverse spin-Hall effect because the temperature differences can result in thermovoltages at the contacts. Because of the non-reciprocity these thermovoltages reverse their sign with a reversal of the magnetic field which is typically deemed the signature of the inverse spin-Hall voltage.

Nonreciprocity of spin waves in magnonic crystals created by surface acoustic waves in structures with yttrium iron garnet

NASA Astrophysics Data System (ADS)

Kryshtal, R. G.; Medved, A. V.

2015-12-01

Experimental results of investigations of nonreciprocity for surface magnetostatic spin waves (SMSW) in the magnonic crystal created by surface acoustic waves (SAW) in yttrium iron garnet films on a gallium gadolinium garnet substrate as without metallization and with aluminum films with different electrical conductivities (thicknesses) are presented. In structures without metallization, the frequency of magnonic gaps is dependent on mutual directions of propagation of the SAW and SMSW, showing nonreciprocal properties for SMSW in SAW - magnonic crystals even with the symmetrical dispersion characteristic. In metalized SAW - magnonic crystals the shift of the magnonic band gaps frequencies at the inversion of the biasing magnetic field was observed. The frequencies of magnonic band gaps as functions of SAW frequency are presented. Measured dependencies, showing the decrease of magnonic gaps frequency and the expansion of the magnonic band gap width with the decreasing of the metal film conductivity are given. Such nonreciprocal properties of the SAW - magnonic crystals are promising for signal processing in the GHz range.

Investigation of concentration-dependence of thermodynamic properties of lanthanum, yttrium, scandium and terbium in eutectic LiCl-KCl molten salt

NASA Astrophysics Data System (ADS)

Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo

2016-09-01

Thermodynamic properties of rare earth metals in LiCl-KCl molten salt electrolyte are crucial to the development of electrochemical separation for the treatment of used nuclear fuels. In the present study, activity coefficient, apparent potential, and diffusion coefficient of lanthanum, yttrium, scandium, and terbium in the molten salt (58 at% LiCl and 42 at% KCl) were calculated by the method of molecular dynamics simulation up to a concentration around 3 at% at temperatures of 723 K and 773 K. It was found that the activity coefficient and the apparent potential increase with the species concentration while diffusion coefficient shows a trend of increase followed by decrease. The calculated results were validated by available measurement data of dilution cases. This research extends the range of data to a wide component and would provide further insight to the pyroprocessing design and safeguards.

Forward volume and surface magnetostatic modes in an yttrium iron garnet film for out-of-plane magnetic fields: Theory and experiment

NASA Astrophysics Data System (ADS)

Lim, Jinho; Bang, Wonbae; Trossman, Jonathan; Amanov, Dovran; Ketterson, John B.

2018-05-01

We present experimental and theoretical results on the propagation of magnetostatic spin waves in a film of yttrium iron garnet (YIG) for out-of-plane magnetic fields for which propagation in opposite directions is nonreciprocal in the presence of a metal layer. The plane studied is defined by the film normal n and n × k where k is the wave vector of the mode. Spin waves in this setting are classified as forward volume waves or surface waves and display non-reciprocity in the presence of an adjacent metal layer except for when H//n. The measurements are carried out in a transmission geometry, and a microwave mixer is used to measure the change of phase, and with it the evolution of wavevector, of the arriving spin wave with external magnetic field.

Potassium titanyl arsenate based cascaded optical parametric oscillator emit at 2.5 µm derived by neodymium-doped yttrium lithium fluoride laser

NASA Astrophysics Data System (ADS)

Duan, Yanmin; Zhang, Jing; Guo, Junhong; Zhu, Haiyong; Zhang, Yongchang; Xu, Changwen; Wang, Hongyan; Zhang, Yaoju

2018-04-01

We reported a potassium titanyl arsenate (KTA) based cascaded optical parametric oscillator (OPO). The secondary OPO signal light at 2.5 µm was obtained with two OPO processes in one non-critical phase matching cut KTA crystal. This cascaded OPO was driven by a Q-switched neodymium-doped yttrium lithium fluoride (Nd:YLF) laser at 1047 nm. Making full use of the negative thermal lens effect and long upper level fluorescence lifetime of Nd:YLF, signal power of 605 mW at 2503 nm was achieved with a pulse repetition frequency of 15 kHz and an incident diode pump power of 9.7 W. Therefore, the cascaded OPO derived by Q-switched Nd:YLF laser could provide high peak power pulsed laser emission in mid-infrared band.

The atomic arrangement of iimoriite-(Y), Y2(SiO4)(CO3)

USGS Publications Warehouse

Hughes, J.M.; Foord, E.E.; Jai-Nhuknan, J.; Bell, J.M.

1996-01-01

Iimoriite-(Y) from Bokan Mountain, Prince of Wales Island, Alaska has been studied using single-crystal X-ray-diffraction techniques. The mineral, ideally Y2(SiO4)(CO3), crystallizes in space group P1, with a 6.5495(13), b 6.6291(14), c 6.4395(11)A??, ?? 116.364(15), ?? 92.556(15) and ?? 95.506(17)??. The atomic arrangement has been solved and refined to an R value of 0.019. The arrangement of atoms consists of alternating (011) slabs of orthosilicate groups and carbonate groups, with no sharing of oxygen atoms between anionic complexes in adjacent slabs. Y1 atoms separate adjacent tetrahedra along [100] within the orthosilicate slab, and Y2 atoms separate adjacent carbonate groups along [100] within the carbonate slab. Adjacent orthosilicate and carbonate slabs are linked in (100) by bonding Y atoms from each slab to oxygen atoms of adjacent slabs, in the form of YO8 polyhedra. The Y1 atoms exist in Y12O14 dimers in the orthosilicate slab, and the Y2 atoms exist in continuous [011] ribbons of edge-sharing Y2O8 polyhedra in the carbonate slab.

Swift heavy ion-beam induced amorphization and recrystallization of yttrium iron garnet.

PubMed

Costantini, Jean-Marc; Miro, Sandrine; Beuneu, François; Toulemonde, Marcel

2015-12-16

Pure and (Ca and Si)-substituted yttrium iron garnet (Y3Fe5O12 or YIG) epitaxial layers and amorphous films on gadolinium gallium garnet (Gd3Ga5O12, or GGG) single crystal substrates were irradiated by 50 MeV (32)Si and 50 MeV (or 60 MeV) (63)Cu ions for electronic stopping powers larger than the threshold value (~4 MeV μm(-1)) for amorphous track formation in YIG crystals. Conductivity data of crystalline samples in a broad ion fluence range (10(11)-10(16) cm(-2)) are modeled with a set of rate equations corresponding to the amorphization and recrystallization induced in ion tracks by electronic excitations. The data for amorphous layers confirm that a recrystallization process takes place above ~10(14) cm(-2). Cross sections for both processes deduced from this analysis are discussed in comparison to previous determinations with reference to the inelastic thermal-spike model of track formation. Micro-Raman spectroscopy was also used to follow the related structural modifications. Raman spectra show the progressive vanishing and randomization of crystal phonon modes in relation to the ion-induced damage. For crystalline samples irradiated at high fluences (⩾10(14) cm(-2)), only two prominent broad bands remain like for amorphous films, thereby reflecting the phonon density of states of the disordered solid, regardless of samples and irradiation conditions. The main band peaked at ~660 cm(-1) is assigned to vibration modes of randomized bonds in tetrahedral (FeO4) units.

Propagation of magnetostatic spin waves in an yttrium iron garnet film for out-of-plane magnetic fields

NASA Astrophysics Data System (ADS)

Bang, Wonbae; Lim, Jinho; Trossman, Jonathan; Tsai, C. C.; Ketterson, John B.

2018-06-01

We have observed the propagation of spin waves across a thin yttrium iron garnet film on (1 1 1) gadolinium gallium garnet for magnetic fields inclined with respect to the film plane. Two principle planes were studied: that for H in the plane defined by the wave vector k and the plane normal, n, with limiting forms corresponding to the Backward Volume and Forward Volume modes, and that for H in the plane perpendicular to k, with limiting forms corresponding to the Damon-Eshbach and Forward Volume modes. By exciting the wave at one edge of the film and observing the field dependence of the phase of the received signal at the opposing edge we determined the frequency vs. wavevector relation, ω = ω (k), of various propagating modes in the film. Avoided crossings are observed in the Damon-Eshbach and Forward Volume regimes when the propagating mode intersects the higher, exchange split, volume modes, leading to an extinction of the propagating mode; analysis of the resulting behavior allows a determination of the exchange parameter. The experimental results are compared with theoretical simulations.

Growth and luminescent properties of Lu 2SiO 5:Ce and (Lu 1- xGd x) 2SiO 5:Ce single crystalline films

NASA Astrophysics Data System (ADS)

Zorenko, Yu.; Gorbenko, V.; Savchyn, V.; Voznyak, T.; Grinyov, B.; Sidletskiy, O.; Kurtsev, D.; Fedorov, A.; Baumer, V.; Nikl, M.; Mares, J. A.; Beitlerova, A.; Prusa, P.; Kucera, M.

2011-12-01

Single crystalline films (SCF) of Lu 2SiO 5:Ce (LSO:Ce), (Lu 1- xGd x) 2SiO 5:Ce (LGSO:Ce) and LGSO:Ce,Tb orthosilicates with thickness of 2.5-21 μm were crystallized by liquid phase epitaxy method onto undoped LSO substrates from melt-solution based on PbO-B 2O 3 flux. The concentration of Gd was varied in the range of x=0.2-0.7 formula units (f.u.). In the case of LGSO:Ce SCF growth we do not use any additional doping for reducing the misfit between the SCF and substrate lattices. The luminescence and scintillation properties of LSO:Ce, LGSO:Ce and LGSO:Ce,Tb SCFs were mutually compared and confronted with the performance of reference LSO:Ce and LYSO:Ce crystals. With increasing Gd content the luminescence spectrum of LGSO:Ce SCF is gradually red-shifted with respect to that of LSO:Ce SCF. The LY of (Lu 1- xGd x)SO:Ce SCF becomes lower in comparison with that for LSO:Ce SC at increasing Gd content in the range of x=0.2-0.7 f.u. The peculiarities of luminescence properties of LSO:Ce and LGSO:Ce SCFs in comparison with crystal analogs are explained by the different distribution of Ce 3+ over Lu1 and Lu2 positions of LSO host and by the influence of Pb 2+ contamination coming from the flux used for the film growth.

Surface-Directed Synthesis of Erbium-Doped Yttrium Oxide Nanoparticles within Organosilane Zeptoliter Containers

PubMed Central

2015-01-01

We introduce an approach to synthesize rare earth oxide nanoparticles using high temperature without aggregation of the nanoparticles. The dispersity of the nanoparticles is controlled at the nanoscale by using small organosilane molds as reaction containers. Zeptoliter reaction vessels prepared from organosilane self-assembled monolayers (SAMs) were used for the surface-directed synthesis of rare earth oxide (REO) nanoparticles. Nanopores of octadecyltrichlorosilane were prepared on Si(111) using particle lithography with immersion steps. The nanopores were filled with a precursor solution of erbium and yttrium salts to confine the crystallization step to occur within individual zeptoliter-sized organosilane reaction vessels. Areas between the nanopores were separated by a matrix film of octadecyltrichlorosilane. With heating, the organosilane template was removed by calcination to generate a surface array of erbium-doped yttria nanoparticles. Nanoparticles synthesized by the surface-directed approach retain the periodic arrangement of the nanopores formed from mesoparticle masks. While bulk rare earth oxides can be readily prepared by solid state methods at high temperature (>900 °C), approaches for preparing REO nanoparticles are limited. Conventional wet chemistry methods are limited to low temperatures according to the boiling points of the solvents used for synthesis. To achieve crystallinity of REO nanoparticles requires steps for high-temperature processing of samples, which can cause self-aggregation and dispersity in sample diameters. The facile steps for particle lithography address the problems of aggregation and the requirement for high-temperature synthesis. PMID:25163977

Metabolic profiling of plasma in overweight/obese and lean men using ultra performance liquid chromatography and Q-TOF mass spectrometry (UPLC-Q-TOF MS).

PubMed

Kim, Ji Young; Park, Ju Yeon; Kim, Oh Yoen; Ham, Bo Mi; Kim, Hyun-Jin; Kwon, Dae Young; Jang, Yangsoo; Lee, Jong Ho

2010-09-03

Obesity is currently epidemic in many countries worldwide and is strongly related to diabetes and cardiovascular disease. This study investigated the differences in metabolomic profiling between overweight/obese and normal-weight men. Overweight/obese (n=30) and age-matched, normal-weight men (n=30) were included. Anthropometric parameters, conventional metabolites, and biomarkers were measured. Metabolomic profiling was analyzed with UPLC-Q-TOF MS. Overweight/obese men showed higher levels of HOMA-IR, triglycerides, total cholesterol, and LDL-cholesterol, and lower levels of HDL-cholesterol and adiponectin than lean men. Overweight/obese men showed higher proportion of stearic acid and lower proportion of oleic acid in serum phospholipids. Additionally, overweight/obese individuals showed higher fat intake and lower ratio of polyunsaturated fatty acids to saturated fatty acids. We identified three lyso-phosphatidylcholine (lysoPC) as potential plasma markers and confirmed eight known metabolites for overweight/obesity men. Especially, overweight/obese subjects showed higher levels of lysoPC C14:0 and lysoPC C18:0 and lower levels of lysoPC C18:1 than lean subjects. Results confirmed abnormal metabolism of two branched-chain amino acids, two aromatic amino acids, and fatty acid synthesis and oxidation in overweight/obese men. Additionally, the amount of dietary saturated fat may influence the proportion of saturated fatty acids in serum phospholipids and the degree of saturation of the constituent acyl group of plasma lysoPC.

Serum Metabonomics of Articular Cartilage Destruction Induced by T-2 Toxin in Wistar Rats.

PubMed

Zhu, Lei; Zhao, Zhi Jun; Ren, Xiao Bin; Li, Qiang; Ding, Hua; Sun, Zhou; Kao, Qing Jun; Wang, Li Hua

2018-01-01

The molecular pathogenesis of T-2 toxin-induced cartilage destruction has not been fully unraveled yet. The aim of this study was to detect changes in serum metabolites in a rat anomaly model with articular cartilage destruction. Thirty healthy male Wistar rats were fed a diet containing T-2 toxin (300 ng/kg chow) for 3 months. Histopathological changes in femorotibial cartilage were characterized in terms of chondrocyte degeneration/necrosis and superficial cartilage defect, and the endogenous metabolite profile of serum was determined by UPLC/Q-TOF MS. Treated rats showed extensive areas of chondrocyte necrosis and superficial cartilage defect in the articular cartilage. In addition, 8 metabolites were found to change significantly in these rats compared to the control group, including lysoPE (18:0/0:0), lysoPC(14:0), lysoPC[18:4 (6Z,9Z,12Z,15Z)], lysoPC[(16:1(9Z)], lysoPC(16:0), L-valine, hippuric acid, and asparaginyl-glycine. These 8 metabolites associated with cartilage injury are mainly involved in phospholipid and amino acid metabolic pathways. Copyright © 2018 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

A defect in the inflammation-primed macrophage-activation cascade in osteopetrotic rats.

PubMed

Yamamoto, N; Lindsay, D D; Naraparaju, V R; Ireland, R A; Popoff, S N

1994-05-15

Macrophages were activated by administration of lysophosphatidylcholine (lyso-Pc) or dodecylglycerol (DDG) to wild-type rats but not in osteopetrotic (op) mutant rats. In vitro treatment of wild-type rat peritoneal cells with lyso-Pc or DDG efficiently activated macrophages whereas treatment of op mutant rat peritoneal cells with lyso-Pc or DDG did not activate macrophages. The inflammation-primed macrophage activation cascade in rats requires participation of B lymphocytes and vitamin D binding protein (DBP). Lyso-Pc-inducible beta-galactosidase of wild-type rat B lymphocytes can convert DBP to the macrophage-activating factor (MAF), whereas B lymphocytes of the op mutant rats were shown to be deficient in lyso-Pc-inducible beta-galactosidase. DBP is conserved among mammalian species. Treatment of human DBP (Gc1 protein) with commercial glycosidases yields an extremely high titrated MAF as assayed on mouse and rat macrophages. Because the enzymatically generated MAF (GcMAF) bypasses the role of lymphocytes in macrophage activation, the op mutant rat macrophages were efficiently activated by administration of a small quantity (100 pg/rat) of GcMAF. Likewise, in vitro treatment of op rat peritoneal cells with as little as 40 pg GcMAF/ml activated macrophages.

State of the art timing in TOF-PET detectors with LuAG, GAGG and L(Y)SO scintillators of various sizes coupled to FBK-SiPMs

NASA Astrophysics Data System (ADS)

Gundacker, S.; Acerbi, F.; Auffray, E.; Ferri, A.; Gola, A.; Nemallapudi, M. V.; Paternoster, G.; Piemonte, C.; Lecoq, P.

2016-08-01

Time of flight (TOF) in positron emission tomography (PET) has experienced a revival of interest after its first introduction in the eighties. This is due to a significant progress in solid state photodetectors (SiPMs) and newly developed scintillators (LSO and its derivatives). Latest developments at Fondazione Bruno Kessler (FBK) lead to the NUV-HD SiPM with a very high photon detection efficiency of around 55%. Despite the large area of 4×4 mm2 it achieves a good single photon time resolution (SPTR) of 180±5ps FWHM. Coincidence time resolution (CTR) measurements using LSO:Ce codoped with Ca scintillators yield best values of 73±2ps FWHM for 2×2×3 mm3 and 117±3ps for 2×2×20 mm3 crystal sizes. Increasing the crystal cross-section from 2×2 mm2 to 3×3 mm2 a non negligible CTR deterioration of approximately 7ps FWHM is observed. Measurements with LSO:Ce codoped Ca and LYSO:Ce scintillators with various cross-sections (1×1 mm2 - 4×4 mm2) and lengths (3mm - 30mm) will be a basis for discussing on how the crystal geometry affects timing in TOF-PET. Special attention is given to SiPM parameters, e.g. SPTR and optical crosstalk, and their measured dependency on the crystal cross-section. Additionally, CTR measurements with LuAG:Ce, LuAG:Pr and GGAG:Ce samples are presented and the results are interpreted in terms of their scintillation properties, e.g. rise time, decay time, light yield and emission spectra.

Materials and fabrication technology of modules intended for irradiation tests of blanket tritium-breeding zones in Russian fusion reactor projects

NASA Astrophysics Data System (ADS)

Kapychev, V.; Davydov, D.; Gorokhov, V.; Ioltukhovskiy, A.; Kazennov, Yu; Tebus, V.; Frolov, V.; Shikov, A.; Shishkov, N.; Kovalenko, V.; Shishkin, N.; Strebkov, Yu

2000-12-01

This paper surveys the modules and materials of blanket tritium-breeding zones developed in the Russian Federation for fusion reactors. Synthesis of lithium orthosilicate, metasilicate and aluminate, fabrication of ceramic pellets and pebbles and experimental reactor units are described. Results of tritium extraction kinetics under irradiation in a water-graphite reactor at a thermal neutron flux of 5×10 13 neutron/(s cm2) are considered. At the present time, development and fabrication of lithium orthosilicate-beryllium modules of the tritium-breeding zone (TBZ), have been carried out within the framework of the ITER and DEMO projects. Two modules containing orthosilicate pellets, porous beryllium and beryllium pebbles are suggested for irradiation tests in the temperature range of 350-700°C. Technical problems associated with manufacturing of the modules are discussed.

Enhancement of Er optical efficiency through bismuth sensitization in yttrium oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarangella, Adriana; Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 64, 95123 Catania; Reitano, Riccardo

2015-07-27

The process of energy transfer (ET) between optically active ions has been widely studied to improve the optical efficiency of a system for different applications, from lighting and photovoltaics to silicon microphotonics. In this work, we report the influence of Bi on the Er optical emission in erbium-yttrium oxide thin films synthesized by magnetron co-sputtering. We demonstrate that this host permits to well dissolve Er and Bi ions, avoiding their clustering, and thus to stabilize the optically active Er{sup 3+} and Bi{sup 3+} valence states. In addition, we establish the ET occurrence from Bi{sup 3+} to Er{sup 3+} by themore » observed Bi{sup 3+} PL emission decrease and the simultaneous Er{sup 3+} photoluminescence (PL) emission increase. This was further confirmed by the coincidence of the Er{sup 3+} and Bi{sup 3+} excitation bands, analyzed by PL excitation spectroscopy. By increasing the Bi content of two orders of magnitude inside the host, though the occurrence of Bi-Bi interactions becomes deleterious for Bi{sup 3+} optical efficiency, the ET process between Bi{sup 3+} and Er{sup 3+} is still prevalent. We estimate ET efficiency of 70% for the optimized Bi:Er ratio equal to 1:3. Moreover, we have demonstrated to enhance the Er{sup 3+} effective excitation cross section by more than three orders of magnitude with respect to the direct one, estimating a value of 5.3 × 10{sup −18} cm{sup 2}, similar to the expected Bi{sup 3+} excitation cross section. This value is one of the highest obtained for Er in Si compatible hosts. These results make this material very promising as an efficient emitter for Si-compatible photonics devices.« less

Fast simulation of yttrium-90 bremsstrahlung photons with GATE.

PubMed

Rault, Erwann; Staelens, Steven; Van Holen, Roel; De Beenhouwer, Jan; Vandenberghe, Stefaan

2010-06-01

Multiple investigators have recently reported the use of yttrium-90 (90Y) bremsstrahlung single photon emission computed tomography (SPECT) imaging for the dosimetry of targeted radionuclide therapies. Because Monte Carlo (MC) simulations are useful for studying SPECT imaging, this study investigates the MC simulation of 90Y bremsstrahlung photons in SPECT. To overcome the computationally expensive simulation of electrons, the authors propose a fast way to simulate the emission of 90Y bremsstrahlung photons based on prerecorded bremsstrahlung photon probability density functions (PDFs). The accuracy of bremsstrahlung photon simulation is evaluated in two steps. First, the validity of the fast bremsstrahlung photon generator is checked. To that end, fast and analog simulations of photons emitted from a 90Y point source in a water phantom are compared. The same setup is then used to verify the accuracy of the bremsstrahlung photon simulations, comparing the results obtained with PDFs generated from both simulated and measured data to measurements. In both cases, the energy spectra and point spread functions of the photons detected in a scintillation camera are used. Results show that the fast simulation method is responsible for a 5% overestimation of the low-energy fluence (below 75 keV) of the bremsstrahlung photons detected using a scintillation camera. The spatial distribution of the detected photons is, however, accurately reproduced with the fast method and a computational acceleration of approximately 17-fold is achieved. When measured PDFs are used in the simulations, the simulated energy spectrum of photons emitted from a point source of 90Y in a water phantom and detected in a scintillation camera closely approximates the measured spectrum. The PSF of the photons imaged in the 50-300 keV energy window is also accurately estimated with a 12.4% underestimation of the full width at half maximum and 4.5% underestimation of the full width at tenth maximum

Refractory open-angle glaucoma after neodymium-yttrium-aluminum-garnet laser lysis of vitreous floaters.

PubMed

Cowan, Lisa A; Khine, Kay T; Chopra, Vikas; Fazio, Doreen T; Francis, Brian A

2015-01-01

To illustrate 3 cases of chronic open-angle glaucoma secondary to the neodymium-yttrium-aluminum-garnet (Nd:YAG) laser vitreolysis procedure for symptomatic vitreous floaters. Observational case series. Location of the study was the Doheny Eye Institute. Three eyes of 2 patients who developed chronic open-angle glaucoma after Nd:YAG vitreolysis for symptomatic floaters presenting with very high intraocular pressure (IOP >40 mm Hg) were selected. The time from the laser treatment to the onset of elevated pressure ranges from 1 week to 8 months. There was no associated inflammation, steroid use, or other identifiable cause of chronic IOP elevation. All eyes were treated initially with glaucoma medication, followed by selective laser trabeculoplasty (SLT) and eventually glaucoma surgery (Trabectome) in 2 eyes for disease management. In all eyes, intraocular pressures were eventually stabilized within a normal pressure range from 18 to 38 months following Nd:YAG vitreolysis. At the latest follow-up post surgery, all eyes had intraocular pressures of 22 mm Hg or less with or without medications. Secondary open-angle glaucoma is a complication of Nd:YAG vitreolysis for symptomatic floaters that may present with an increase in intraocular pressure immediately, or many months after the surgery. Furthermore this complication may be permanent and require chronic medical therapy or glaucoma surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

Far-infrared spectra of yttrium-doped gold clusters Au(n)Y (n=1-9).

PubMed

Lin, Ling; Claes, Pieterjan; Gruene, Philipp; Meijer, Gerard; Fielicke, André; Nguyen, Minh Tho; Lievens, Peter

2010-06-21

The geometric, spectroscopic, and electronic properties of neutral yttrium-doped gold clusters Au(n)Y (n=1-9) are studied by far-infrared multiple photon dissociation (FIR-MPD) spectroscopy and quantum chemical calculations. Comparison of the observed and calculated vibrational spectra allows the structures of the isomers present in the molecular beam to be determined. Most of the isomers for which the IR spectra agree best with experiment are calculated to be the energetically most stable ones. Attachment of xenon to the Au(n)Y cluster can cause changes in the IR spectra, which involve band shifts and band splittings. In some cases symmetry changes, as a result of the attachment of xenon atoms, were also observed. All the Au(n)Y clusters considered prefer a low spin state. In contrast to pure gold clusters, which exhibit exclusively planar lowest-energy structures for small sizes, several of the studied species are three-dimensional. This is particularly the case for Au(4)Y and Au(9)Y, while for some other sizes (n=5, 8) the 3D structures have an energy similar to that of their 2D counterparts. Several of the lowest-energy structures are quasi-2D, that is, slightly distorted from planar shapes. For all the studied species the Y atom prefers high coordination, which is different from other metal dopants in gold clusters.

Structure-substitution limit correlation study on Cr{sup 3+} substituted polycrystalline yttrium iron garnet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Modi, K. B.; Saija, K. G.; Sharma, P. U.

2016-05-06

Polycrystalline samples of Cr{sup 3+} - substituted yttrium iron garnet (Y{sub 3}Fe{sub 5}O{sub 12}) system with general chemical formula, Y{sub 3}Fe{sub 5-x}Cr{sub x}O{sub 12}, x = 0.0, 0.2, 0.4 and 0.6 were synthesized by double sintering ceramic technique and characterized by X-ray powder diffractometry. The Rietveld fitted X-ray diffraction patterns analysis revealed mono phase formation for x = 0.0 - 0.4 compositions while x = 0.6 composition possesses mixed phase character. The observed substitution limit has been discussed in the light of ionic size of substituent, electrostatic energy, electronic configuration and synthesis parameters. These observations strongly suggest that the electronicmore » configuration of Cr{sup 3+}, which is favorable to the formation of d2sp3 (octahedral) type bonds, must be important. In the case of Cr{sup 3+}, the substitution does not appear to proceed well for x much greater than 0.5, this limitation probably is a consequence of the strong preference of a smaller ion Cr{sup 3+}, for a larger octahedral site which quickly leads to a condition not comparable with the requirement of the structure. The distribution of cations, mean ionic radii and theoretical lattice constant values have been determined.« less

Yttrium Iron Garnet Thin Films with Very Low Damping Obtained by Recrystallization of Amorphous Material

PubMed Central

Hauser, Christoph; Richter, Tim; Homonnay, Nico; Eisenschmidt, Christian; Qaid, Mohammad; Deniz, Hakan; Hesse, Dietrich; Sawicki, Maciej; Ebbinghaus, Stefan G.; Schmidt, Georg

2016-01-01

We have investigated recrystallization of amorphous Yttrium Iron Garnet (YIG) by annealing in oxygen atmosphere. Our findings show that well below the melting temperature the material transforms into a fully epitaxial layer with exceptional quality, both structural and magnetic. In ferromagnetic resonance (FMR) ultra low damping and extremely narrow linewidth can be observed. For a 56 nm thick layer a damping constant of α = (6.15 ± 1.50) · 10−5 is found and the linewidth at 9.6 GHz is as small as 1.30 ± 0.05 Oe which are the lowest values for PLD grown thin films reported so far. Even for a 20 nm thick layer a damping constant of α = (7.35 ± 1.40) · 10−5 is found which is the lowest value for ultrathin films published so far. The FMR linewidth in this case is 3.49 ± 0.10 Oe at 9.6 GHz. Our results not only present a method of depositing thin film YIG of unprecedented quality but also open up new options for the fabrication of thin film complex oxides or even other crystalline materials. PMID:26860816

Dynamic photopatterning of cells in situ by Q-switched neodymium-doped yttrium ortho-vanadate laser.

PubMed

Deka, Gitanjal; Okano, Kazunori; Kao, Fu-Jen

2014-01-01

Cellular micropattering has been increasingly adopted in quantitative biological experiments. A Q-switched pulsed neodymium-doped yttrium ortho-vanadate (Nd∶YVO4) laser directed in-situ microfabrication technique for cell patterning is presented. A platform is designed uniquely to achieve laser ablation. The platform is comprised of thin gold coating over a glass surface that functions as a thermal transducer and is over-layered by a cell repellant polymer layer. Micropatterns are engraved on the platform, subsequently exposing specific cell adhesive micro-domains by ablating the gold-polymer coating photothermally. Experimental results indicate that the proposed approach is applicable under culture conditions, viable toward cells, and has a higher engraving speed. Possible uses in arraying isolated single cells on the platform are also shown. Additionally, based on those micro-patterns, dynamic cellular morphological changes and migrational speed in response to geometrical barriers are studied to demonstrate the potential applications of the proposed approach. Our results further demonstrate that cells in narrower geometry had elongated shapes and higher migrational speed than those in wider geometry. Importantly, the proposed approach will provide a valuable reference for efforts to study single cell dynamics and cellular migration related processes for areas such as cell division, wound healing, and cancer invasion.

Observation of electromagnetically induced transparency and absorption in Yttrium Iron Garnet loaded split ring resonator

NASA Astrophysics Data System (ADS)

Tay, Z. J.; Soh, W. T.; Ong, C. K.

2018-04-01

In this paper, we propose a new method of controlling microwave transmission from Electromagnetically Induced Absorption (EIA) to Electromagnetically Induced Transparency (EIT). EIA describes the state where the system strongly absorbs microwaves, whereas EIT describes the state in which the system is transparent to microwaves. Control is achieved via coupling of the 3 GHz photon mode of a metamaterial Split Ring Resonator (SRR) to the spin wave magnon modes of a Yttrium Iron Garnet (YIG) bulk. The system is described by a 2-body interaction matrix with an additional fitting parameter τ which takes into account the fact that the microstrip feed line could excite the SRR as well as the YIG. The parameter τ reveals the effect of geometry and shielding on the coupling behaviour and gives rise to unique physics. In low τ (τ ⩽ 2) configurations, only EIT is reported. However, in high τ (τ ≈ 10) configurations, EIA is reported. Furthermore, we report that the system can be easily changed from a low τ to high τ configuration by shielding the SRR from the microstrip with a thin metal piece. Varying the τ parameter through shielding is thus proposed as a new method of controlling the microwave transmission at the coupling region.

Shape-Controlled Synthesis of Isotopic Yttrium-90-Labeled Rare Earth Fluoride Nanocrystals for Multimodal Imaging.

PubMed

Paik, Taejong; Chacko, Ann-Marie; Mikitsh, John L; Friedberg, Joseph S; Pryma, Daniel A; Murray, Christopher B

2015-09-22

Isotopically labeled nanomaterials have recently attracted much attention in biomedical research, environmental health studies, and clinical medicine because radioactive probes allow the elucidation of in vitro and in vivo cellular transport mechanisms, as well as the unambiguous distribution and localization of nanomaterials in vivo. In addition, nanocrystal-based inorganic materials have a unique capability of customizing size, shape, and composition; with the potential to be designed as multimodal imaging probes. Size and shape of nanocrystals can directly influence interactions with biological systems, hence it is important to develop synthetic methods to design radiolabeled nanocrystals with precise control of size and shape. Here, we report size- and shape-controlled synthesis of rare earth fluoride nanocrystals doped with the β-emitting radioisotope yttrium-90 ((90)Y). Size and shape of nanocrystals are tailored via tight control of reaction parameters and the type of rare earth hosts (e.g., Gd or Y) employed. Radiolabeled nanocrystals are synthesized in high radiochemical yield and purity as well as excellent radiolabel stability in the face of surface modification with different polymeric ligands. We demonstrate the Cerenkov radioluminescence imaging and magnetic resonance imaging capabilities of (90)Y-doped GdF3 nanoplates, which offer unique opportunities as a promising platform for multimodal imaging and targeted therapy.

Hanford isotope project strategic business analysis yttrium-90 (Y-90)

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-10-01

The purpose of this analysis is to address the short-term direction for the Hanford yttrium-90 (Y-90) project. Hanford is the sole DOE producer of Y-90, and is the largest repository for its source in this country. The production of Y-90 is part of the DOE Isotope Production and Distribution (IP and D) mission. The Y-90 is ``milked`` from strontium-90 (Sr-90), a byproduct of the previous Hanford missions. The use of Sr-90 to produce Y-90 could help reduce the amount of waste material processed and the related costs incurred by the clean-up mission, while providing medical and economic benefits. The costmore » of producing Y-90 is being subsidized by DOE-IP and D due to its use for research, and resultant low production level. It is possible that the sales of Y-90 could produce full cost recovery within two to three years, at two curies per week. Preliminary projections place the demand at between 20,000 and 50,000 curies per year within the next ten years, assuming FDA approval of one or more of the current therapies now in clinical trials. This level of production would incentivize private firms to commercialize the operation, and allow the government to recover some of its sunk costs. There are a number of potential barriers to the success of the Y-90 project, outside the control of the Hanford Site. The key issues include: efficacy, Food and Drug Administration (FDA) approval and medical community acceptance. There are at least three other sources for Y-90 available to the US users, but they appear to have limited resources to produce the isotope. Several companies have communicated interest in entering into agreements with Hanford for the processing and distribution of Y-90, including some of the major pharmaceutical firms in this country.« less

Quantitative and Qualitative Assessment of Yttrium-90 PET/CT Imaging

PubMed Central

Büsing, Karen-Anett; Schönberg, Stefan O.; Bailey, Dale L.; Willowson, Kathy; Glatting, Gerhard

2014-01-01

Yttrium-90 is known to have a low positron emission decay of 32 ppm that may allow for personalized dosimetry of liver cancer therapy with 90Y labeled microspheres. The aim of this work was to image and quantify 90Y so that accurate predictions of the absorbed dose can be made. The measurements were performed within the QUEST study (University of Sydney, and Sirtex Medical, Australia). A NEMA IEC body phantom containing 6 fillable spheres (10–37 mm ∅) was used to measure the 90Y distribution with a Biograph mCT PET/CT (Siemens, Erlangen, Germany) with time-of-flight (TOF) acquisition. A sphere to background ratio of 8∶1, with a total 90Y activity of 3 GBq was used. Measurements were performed for one week (0, 3, 5 and 7 d). he acquisition protocol consisted of 30 min-2 bed positions and 120 min-single bed position. mages were reconstructed with 3D ordered subset expectation maximization (OSEM) and point spread function (PSF) for iteration numbers of 1–12 with 21 (TOF) and 24 (non-TOF) subsets and CT based attenuation and scatter correction. Convergence of algorithms and activity recovery was assessed based on regions-of-interest (ROI) analysis of the background (100 voxels), spheres (4 voxels) and the central low density insert (25 voxels). For the largest sphere, the recovery coefficient (RC) values for the 30 min –2-bed position, 30 min-single bed and 120 min-single bed were 1.12±0.20, 1.14±0.13, 0.97±0.07 respectively. For the smaller diameter spheres, the PSF algorithm with TOF and single bed acquisition provided a comparatively better activity recovery. Quantification of Y-90 using Biograph mCT PET/CT is possible with a reasonable accuracy, the limitations being the size of the lesion and the activity concentration present. At this stage, based on our study, it seems advantageous to use different protocols depending on the size of the lesion. PMID:25369020

Multi-directional emission and detection of spin waves propagating in yttrium iron garnet with wavelengths down to about 100 nm

NASA Astrophysics Data System (ADS)

Maendl, Stefan; Grundler, Dirk

2018-05-01

We performed broadband spin-wave spectroscopy on 200 nm thick yttrium iron garnet containing arrays of partially embedded magnetic nanodisks. Using integrated coplanar waveguides (CPWs), we studied the excitation and transmission of spin waves depending on the presence of nanomagnet arrays of different lateral extensions. By means of the grating coupler effect, we excited spin waves propagating in multiple lateral directions with wavelengths down to 111 nm. They exhibited group velocities of up to 1 km/s. Detection of such short-wavelength spin waves was possible only in symmetrically designed emitter/detector configurations, not with a bare CPW. We report spin waves propagating between grating couplers under oblique angles exhibiting a wave vector component parallel to the CPW. The effective propagation distance amounted to about 80 μm. Such transmission signals were not addressed before and substantiate the versatility of the grating coupler effect for implementing nanomagnonic circuits.

[Contralateral hepatic hypertrophy following unilateral yttrium-90 radioembolization : Implications for liver surgery].

PubMed

Garlipp, B; Seidensticker, M; Jechorek, D; Ptok, H; Bruns, C J; Ricke, J

2016-05-01

Preservation of an adequate future liver remnant (FLR) is the principal limitation to liver surgery in patients with primary or secondary liver malignancies. Hence, methods to increase the volume of the FLR in preparation for liver resection are gaining in importance. In addition to the traditional methods for induction of FLR hypertrophy, such as portal vein embolization (PVE) or portal vein ligation (PVL) with or without parenchymal dissection (ALPPS, in situ split), radioembolization (RE) using yttrium-90 microspheres also leads to a volume increase of non-embolized liver parenchyma. This review outlines its potential role as an alternative procedure for induction of liver hypertrophy. Synopsis and critical discussion of the available literature on the mechanisms of induction of liver hypertrophy, the advantages and drawbacks of the traditional methods, and current research on volume changes associated with RE as well as their implications for possible clinical use in preparation for liver surgery. Both PVE and PVL can achieve a substantial contralateral volume gain of up to 70 %. The development of contralateral hypertrophy can be accelerated by dissecting the liver parenchyma along the intended plane of resection in addition to PVL (in situ split). Compared to these methods, RE achieves less contralateral liver hypertrophy; however, this effect should not be disregarded as RE provides effective treatment of ipsilateral liver tumors along with induction of hypertrophy and may be associated with a reduced risk of tumor progression compared to PVE and PVL. The available data suggest that RE can complement the armamentarium of methods for induction of FLR hypertrophy in specific situations. Further studies are needed to establish its definitive role for this indication and are in preparation.

Comparison of the partitioning behaviours of yttrium, rare earth elements, and titanium between hydrogenetic marine ferromanganese crusts and seawater

USGS Publications Warehouse

Bau, M.; Koschinsky, A.; Dulski, P.; Hein, J.R.

1996-01-01

In order to evaluate details of the partitioning behaviours of Y, rare earth elements (REEs), and Ti between inorganic metal oxide surfaces and seawater, we studied the distribution of these elements in hydrogenetic marine ferromanganese (Fe-Mn) crusts from the Central Pacific Ocean. Nonphosphatized Fe-Mn crusts display shale-normalized rare earths and yttrium (REYSN) patterns (Y inserted between Dy and Ho) that are depleted in light REEs (LREEs) and which show negative anomalies for YSN, and positive anomalies for LaSN, EuSN, GdSN, and in most cases, CeSN. They show considerably smaller Y/ Ho ratios than seawater or common igneous and clastic rocks, indicating that Y and Ho are fractionated in the marine environment. Compared to P-poor crusts, REYSN patterns of phosphatized Fe-Mn crusts are similar, but yield pronounced positive YSN anomalies, stronger positive LaSN anomalies, and enrichment of the HREEs relative to the MREEs. The data suggest modification of REY during phosphatization and indicate that studies requiring primary REY distributions or isotopic ratios should be restricted to nonphosphatized (layers of) Fe-Mn crusts. Apparent bulk coefficients, KMD, describing trace metal partitioning between nonphosphatized hydrogenetic Fe-Mn crusts and seawater, are similar for Pr to Eu and decrease for Eu to Yb. Exceptionally high values of KCeD, which are similar to those of Ti, result from oxidative scavenging of Ce and support previous suggestions that Ce(IV) is a hydroxide-dominated element in seawater. Yttrium and Gd show lower KD values than their respective neighbours in the REY series. Results of modelling the exchange equilibrium between REY dissolved in seawater and REY sorbed on hydrous Fe-Mn oxides corroborate previous studies that suggested the surface complexation of REY can be approximated by their first hydroxide binding constant. Negative "anomalies" occur for stabilities of bulk surface complexes of Gd, La, and particularly Y. The differences in

Spectral characterization and white light generation by yttrium silicate nanopowders undoped and doped with Ytterbium(III) at different concentrations when excited by a laser diode at 975 nm

NASA Astrophysics Data System (ADS)

Cinkaya, Hatun; Eryurek, Gonul; Bilir, Gokhan; Collins, John; Di Bartolo, Baldassare

2017-01-01

We have studied nanophosphors of yttrium silicate (YSO) undoped and doped with different concentration of ytterbium (Yb3+) synthesized by using the sol-gel method. Structural and luminescence properties of the nanophosphors were studied experimentally by using different analytical techniques. For the structural analysis, we performed X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectrometry (EDS) measurements. Upconversion (UC) and the white light (WL) emission properties were investigated by using the near infrared cw laser excitation of 975 nm. The spectral properties have been found to depend on several physical parameters.

Mass Spectrometry Analysis of Wild-Type and Knock-in Q140/Q140 Huntington's Disease Mouse Brains Reveals Changes in Glycerophospholipids Including Alterations in Phosphatidic Acid and Lyso-Phosphatidic Acid.

PubMed

Vodicka, Petr; Mo, Shunyan; Tousley, Adelaide; Green, Karin M; Sapp, Ellen; Iuliano, Maria; Sadri-Vakili, Ghazaleh; Shaffer, Scott A; Aronin, Neil; DiFiglia, Marian; Kegel-Gleason, Kimberly B

2015-01-01

Huntington's disease (HD) is a neurodegenerative disease caused by a CAG expansion in the HD gene, which encodes the protein Huntingtin. Huntingtin associates with membranes and can interact directly with glycerophospholipids in membranes. We analyzed glycerophospholipid profiles from brains of 11 month old wild-type (WT) and Q140/Q140 HD knock-in mice to assess potential changes in glycerophospholipid metabolism. Polar lipids from cerebellum, cortex, and striatum were extracted and analyzed by liquid chromatography and negative ion electrospray tandem mass spectrometry analysis (LC-MS/MS). Gene products involved in polar lipid metabolism were studied using western blotting, immuno-electron microscopy and qPCR. Significant changes in numerous species of glycerophosphate (phosphatidic acid, PA) were found in striatum, cerebellum and cortex from Q140/Q140 HD mice compared to WT mice at 11 months. Changes in specific species could also be detected for other glycerophospholipids. Increases in species of lyso-PA (LPA) were measured in striatum of Q140/Q140 HD mice compared to WT. Protein levels for c-terminal binding protein 1 (CtBP1), a regulator of PA biosynthesis, were reduced in striatal synaptosomes from HD mice compared to wild-type at 6 and 12 months. Immunoreactivity for CtBP1 was detected on membranes of synaptic vesicles in striatal axon terminals in the globus pallidus. These novel results identify a potential site of molecular pathology caused by mutant Huntingtin that may impart early changes in HD.

Yttrium-90 radioembolization as a bridge to liver transplantation: a single-institution experience.

PubMed

Tohme, Samer; Sukato, Daniel; Chen, Hui-Wei; Amesur, Nikhil; Zajko, Albert B; Humar, Abhinav; Geller, David A; Marsh, James W; Tsung, Allan

2013-11-01

To evaluate our experience with the use of yttrium-90 ((90)Y) radioembolization in maintaining potential candidacy and, in some instances, downstaging hepatocellular carcinoma (HCC) that does not meet Milan criteria for liver transplantation. A retrospective review of 20 consecutive patients with HCC who were listed to receive a liver transplant and were treated with (90)Y radioembolization as a sole modality for locoregional "bridge" therapy was performed. Demographics, radiographic and pathologic response, survival, and recurrences were examined. Twenty-two (90)Y treatments were performed in 20 patients before transplantation. Median time from first treatment to transplantation was 3.5 months. HCC in 14 patients met the Milan criteria at the time of the first (90)Y treatment, and HCC in six did not. All cases that originally met the Milan criteria remained within the criteria before transplantation, and two of six patients whose disease did not meet the criteria (33%) had their disease successfully downstaged to meet the criteria. Overall, nine patients (45%) had complete or partial radiologic response to (90)Y radioembolization according to modified Response Evaluation Criteria In Solid Tumors. Complete necrosis of tumor with no evidence of viable tumor on pathologic examination was observed in five patients (36%) whose disease met the Milan criteria. Particularly in regions with long wait list times, (90)Y treatment is effective in maintaining tumor size in potential liver transplantation candidates with HCC. In addition, it can also be considered as a downstaging therapy in select patients before transplantation. © SIR, 2013.

Treating and Downstaging Hepatocellular Carcinoma in the Caudate Lobe with Yttrium-90 Radioembolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibrahim, Saad M.; Kulik, Laura; Baker, Talia

2012-10-15

Purpose: This study was designed to determine the technical feasibility, safety, efficacy, and potential to downstage patients to within transplantation criteria when treating patients with hepatocellular carcinoma (HCC) of the caudate lobe using Y90 radioembolization. Methods: During a 4-year period, 8 of 291 patients treated with radioembolization for unresectable HCC had disease involving the caudate lobe. All patients were followed for treatment-related clinical/biochemical toxicities, serum tumor marker response, and treatment response. Imaging response was assessed with the World Health Organization (WHO) and European Association for the Study of the Liver (EASL) classification schemes. Pathologic response was reported as percent necrosismore » at explantation. Results: Caudate lobe radioembolization was successfully performed in all eight patients. All patients presented with both cirrhosis and portal hypertension. Half were United Network for Organ Sharing (UNOS) stage T3 (n = 4, 50%). Fatigue was reported in half of the patients (n = 4, 50%). One (13%) grade 3/4 bilirubin toxicity was reported. One patient (13%) showed complete tumor response by WHO criteria, and three patients (38%) showed complete response using EASL guidelines. Serum AFP decreased by more than 50% in most patients (n = 6, 75%). Four patients (50%) were UNOS downstaged from T3 to T2, three of who underwent transplantation. One specimen showed histopathologic evidence of 100% complete necrosis, and two specimens demonstrated greater than 50% necrosis. Conclusions: Radioembolization with yttrium-90 appears to be a feasible, safe, and effective treatment option for patients with unresectable caudate lobe HCC. It has the potential to downstage patients to transplantation.« less

Spin Seebeck effect and ballistic transport of quasi-acoustic magnons in room-temperature yttrium iron garnet films

NASA Astrophysics Data System (ADS)

Noack, Timo B.; Musiienko-Shmarova, Halyna Yu; Langner, Thomas; Heussner, Frank; Lauer, Viktor; Heinz, Björn; Bozhko, Dmytro A.; Vasyuchka, Vitaliy I.; Pomyalov, Anna; L’vov, Victor S.; Hillebrands, Burkard; Serga, Alexander A.

2018-06-01

We studied the transient behavior of the spin current generated by the longitudinal spin Seebeck effect (LSSE) in a set of platinum-coated yttrium iron garnet (YIG) films of different thicknesses. The LSSE was induced by means of pulsed microwave heating of the Pt layer and the spin currents were measured electrically using the inverse spin Hall effect in the same layer. We demonstrate that the time evolution of the LSSE is determined by the evolution of the thermal gradient triggering the flux of thermal magnons in the vicinity of the YIG/Pt interface. These magnons move ballistically within the YIG film with a constant group velocity, while their number decays exponentially within an effective propagation length. The ballistic flight of the magnons with energies above 20 K is a result of their almost linear dispersion law, similar to that of acoustic phonons. By fitting the time-dependent LSSE signal for different film thicknesses varying by almost an order of magnitude, we found that the effective propagation length is practically independent of the YIG film thickness. We consider this fact as strong support of a ballistic transport scenario—the ballistic propagation of quasi-acoustic magnons in room temperature YIG.

Preparation and Characterization of Chromium(III)-Activated Yttrium Aluminum Borate: A New Thermographic Phosphor for Optical Sensing and Imaging at Ambient Temperatures

PubMed Central

2010-01-01

A new thermographic phosphor based on chromium(III)-doped yttrium aluminum borate (YAB) is obtained as single crystals by high temperature flux growth and as a microcrystalline powder via solution combustion synthesis. The phosphor is excitable both in the blue (λmax 422 nm) and in the red part of the spectrum (λmax 600 nm) and shows bright NIR emission. The brightness of the phosphor is comparable to that of a well-known lamp phosphor Mn(IV)-doped magnesium fluorogermanate. At ambient temperatures, the Cr(III)-doped YAB shows high temperature dependence of the luminescence decay time, which approaches 1% per deg. The material shows no decrease in luminescence intensity at higher temperatures. The new phosphor is particularly promising for applications in temperature-compensated optical chemosensors (including those based on NIR-emitting indicators) and in pressure-sensitive paints. PMID:20473368

Observation of yttrium oxide nanoparticles in cabbage (Brassica oleracea) through dual energy K-edge subtraction imaging

DOE PAGES

Chen, Yunyun; Sanchez, Carlos; Yue, Yuan; ...

2016-03-25

Background: The potential transfer of engineered nanoparticles (ENPs) from plants into the food chain has raised widespread concerns. In order to investigate the effects of ENPs on plants, young cabbage plants (Brassica oleracea) were exposed to a hydroponic system containing yttrium oxide (yttria) ENPs. The objective of this study was to reveal the impacts of NPs on plants by using K-edge subtraction imaging technique. Results: Using synchrotron dual-e nergy X-ray micro-tomography with K-edge subtraction technique, we studied the uptake, accumulation, distribution and concentration mapping of yttria ENPs in cabbage plants. It was found that yttria ENPs were uptaken by themore » cabbage roots but did not effectively transferred and mobilized through the cabbage stem and leaves. This could be due to the accumulation of yttria ENPs blocked at primary-lateral-root junction. Instead, non-yttria minerals were found in the xylem vessels of roots and stem. Conclusions: Synchrotron dual-energy X-ray micro-tomography is an effective method to observe yttria NPs inside the cabbage plants in both whole body and microscale level. Furthermore, the blockage of a plant's roots by nanoparticles is likely the first and potentially fatal environmental effect of such type of nanoparticles.« less

Nonlocal magnon spin transport in yttrium iron garnet with tantalum and platinum spin injection/detection electrodes

NASA Astrophysics Data System (ADS)

Liu, J.; Cornelissen, L. J.; Shan, J.; van Wees, B. J.; Kuschel, T.

2018-06-01

We study the magnon spin transport in the magnetic insulator yttrium iron garnet (YIG) in a nonlocal experiment and compare the magnon spin excitation and detection for the heavy metal paramagnetic electrodes platinum (Pt|YIG|Pt) and tantalum (Ta|YIG|Ta). The electrical injection and detection processes rely on the (inverse) spin Hall effect in the heavy metals and the conversion between the electron spin and magnon spin at the heavy metal|YIG interface. Pt and Ta possess opposite signs of the spin Hall angle. Furthermore, their heterostructures with YIG have different interface properties, i.e. spin mixing conductances. By varying the distance between injector and detector, the magnon spin transport is studied. Using a circuit model based on the diffusion-relaxation transport theory, a similar magnon relaxation length of  ∼10 μm was extracted from both Pt and Ta devices. By changing the injector and detector material from Pt to Ta, the influence of interface properties on the magnon spin transport has been observed. For Ta devices on YIG the spin mixing conductance is reduced compared with Pt devices, which is quantitatively consistent when comparing the dependence of the nonlocal signal on the injector-detector distance with the prediction from the circuit model.

Novel technique for generating macrophage foam cells for in vitro reverse cholesterol transport studies[S

PubMed Central

Sengupta, Bhaswati; Narasimhulu, Chandrakala Aluganti; Parthasarathy, Sampath

2013-01-01

Generation of foam cells, an essential step for reverse cholesterol transport studies, uses the technique of receptor-dependent macrophage loading with radiolabeled acetylated LDL. In this study, we used the ability of a biologically relevant detergent molecule, lysophosphatidylcholine (lyso-PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabeled cholesterol/lyso-PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4°C and retained the solubilized cholesterol during one month of storage. Macrophages incubated with cholesterol or CE (unlabeled, fluorescently labeled, or radiolabeled)/lyso-PtdCho mixed micelles accumulated CE as documented by microscopy, lipid staining, labeled oleate incorporation, and by TLC. Such foam cells unloaded cholesterol when incubated with HDL but not with oxidized HDL. We propose that stable cholesterol or CE/lyso-PtdCho micelles would offer advantages over existing methods. PMID:24115226

Ce and La single- and double-substitutional defects in yttrium aluminum garnet: first-principles study.

PubMed

Muñoz-García, Ana Belén; Seijo, Luis

2011-02-10

The atomistic structure, energetics, and electronic structure of single-substitutional Ce and La defects and double-substitutional Ce-La defects in Ce,La-codoped yttrium aluminum garnet (YAG) Y(3)Al(5)O(12) have been studied by means of first-principles periodic boundary conditions density functional theory calculations. Single substitution of Y by Ce or by La produces atomistic expansions around the impurities, which are significantly smaller than the ionic radii mismatches and the overall lattice distortions are found to be confined within their second coordination spheres. In double-substitutional defects, the impurities tend to be as close as possible. La-codoping Ce:YAG provokes an anisotropic expansion around Ce defects. The Ce impurity introduces 4f occupied states in the 5.0 eV computed gap of YAG, peaking 0.25 eV above the top of the valence band, and empty 4f, 5d, and 6s states starting at 3.8 eV in the gap and spreading over the conduction band. La-codoping produces very small effects on the electronic structure of Ce:YAG, the most visible one being the decrease in covalent bonding with one of the oxygen atoms, which shifts 0.05 Å away from Ce and gets 0.04 Å closer to La in the most stable Ce-La double-substitutional defect.

Patient Selection and Activity Planning Guide for Selective Internal Radiotherapy With Yttrium-90 Resin Microspheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lau, Wan-Yee, E-mail: josephlau@surgery.cuhk.edu.hk; Kennedy, Andrew S.; Department of Biomedical Engineering, North Carolina State University, Raleigh, NC

Purpose: Selective internal radiotherapy (SIRT) with yttrium-90 ({sup 90}Y) resin microspheres can improve the clinical outcomes for selected patients with inoperable liver cancer. This technique involves intra-arterial delivery of {beta}-emitting microspheres into hepatocellular carcinomas or liver metastases while sparing uninvolved structures. Its unique mode of action, including both {sup 90}Y brachytherapy and embolization of neoplastic microvasculature, necessitates activity planning methods specific to SIRT. Methods and Materials: A panel of clinicians experienced in {sup 90}Y resin microsphere SIRT was convened to integrate clinical experience with the published data to propose an activity planning pathway for radioembolization. Results: Accurate planning is essentialmore » to minimize potentially fatal sequelae such as radiation-induced liver disease while delivering tumoricidal {sup 90}Y activity. Planning methods have included empiric dosing according to degree of tumor involvement, empiric dosing adjusted for the body surface area, and partition model calculations using Medical Internal Radiation Dose principles. It has been recommended that at least two of these methods be compared when calculating the microsphere activity for each patient. Conclusions: Many factors inform {sup 90}Y resin microsphere SIRT activity planning, including the therapeutic intent, tissue and vasculature imaging, tumor and uninvolved liver characteristics, previous therapies, and localization of the microsphere infusion. The influence of each of these factors has been discussed.« less

Clonorchis sinensis lysophospholipase A upregulates IL-25 expression in macrophages as a potential pathway to liver fibrosis.

PubMed

Zhou, Lina; Shi, Mengchen; Zhao, Lu; Lin, Zhipeng; Tang, Zeli; Sun, Hengchang; Chen, Tingjin; Lv, Zhiyue; Xu, Jin; Huang, Yan; Yu, Xinbing

2017-06-17

Liver fibrosis is an excessive wound-healing reaction that requires the participation of inflammatory cells and hepatic stellate cells (HSCs). The pathogenesis of liver fibrosis caused by viruses and alcohol has been well characterized, but the molecular mechanisms underlying liver fibrosis induced by the liver fluke Clonorchis sinensis are poorly understood. Lysophospholipase A (LysoPLA), which deacylates lysophospholipids, plays a critical role in mediating the virulence and pathogenesis of parasites and fungi; however, the roles of C. sinensis lysophospholipase A (CsLysoPLA) in C. sinensis-induced liver fibrosis remain unknown. A mouse macrophage cell line (RAW264.7) was cultured and treated with CsLysoPLA. IL-25 and members of its associated signaling pathway were detected by performing quantitative real-time PCR, Western blotting and immunofluorescent staining. A human hepatic stellate cell line (LX-2) was cultured and exposed to IL-25. LX-2 cell activation markers were examined via quantitative real-time PCR, Western blotting and immunofluorescent staining. Migration was analyzed in transwell plates. Treating RAW264.7 cells with CsLysoPLA significantly induced IL-25 expression. Elevated PKA, B-Raf, and ERK1/2 mRNA levels and phosphorylated B-Raf and ERK1/2 were detected in CsLysoPLA-stimulated RAW264.7 cells. The PKA inhibitor H-89 weakened B-Raf and ERK1/2 phosphorylation whereas the AKT activator SC79 attenuated ERK1/2 phosphorylation in RAW264.7 cells. Both H-89 and SC79 inhibited CsLysoPLA-induced IL-25 upregulation. In addition, stimulation of LX-2 cells with IL-25 upregulated the expression of mesenchymal cell markers, including α-smooth muscle actin (α-SMA) and collagen type I (Collagen-I), and promoted cell migration. CsLysoPLA activates HSCs by upregulating IL-25 in macrophages through the PKA-dependent B-Raf/ERK1/2 pathway and potentially promotes hepatic fibrosis during C. sinensis infection.

Temperature-dependent relaxation of dipole-exchange magnons in yttrium iron garnet films

NASA Astrophysics Data System (ADS)

Mihalceanu, Laura; Vasyuchka, Vitaliy I.; Bozhko, Dmytro A.; Langner, Thomas; Nechiporuk, Alexey Yu.; Romanyuk, Vladyslav F.; Hillebrands, Burkard; Serga, Alexander A.

2018-06-01

Low-energy consumption enabled by charge-free information transport, which is free from Joule heating, and the ability to process phase-encoded data through the use of nanometer-sized interference devices operating at GHz and THz frequencies are just a few benefits of spin-wave-based technologies. Moreover, when approaching cryogenic temperatures, quantum phenomena in spin-wave systems pave the path towards quantum information processing. In view of these applications, the lifetime of magnons—spin-wave quanta—is of high relevance for the fields of magnonics, magnon spintronics, and quantum computing. Here, the relaxation behavior of parametrically excited magnons having wave numbers from zero up to 6 ×105rad cm-1 was experimentally investigated in the temperature range from 20 to 340 K in single-crystal yttrium iron garnet (YIG) films of different thickness epitaxially grown on gallium gadolinium garnet (GGG) substrates as well as in a bulk YIG crystal—the magnonic materials featuring the lowest magnetic damping thus far known. Due to magnon-magnon interactions, the relaxation rate of the parametric magnons increases with an increase of their wave numbers. In the thinner samples, this increase is less pronounced, which can be associated with a stronger quantization of their magnon spectra. For the YIG films, we have found a significant increase in the magnon relaxation rate below 150 K—up to eight times the reference value at 340 K—in the entire range of probed wave numbers, which is in direct opposition to that in ultrapure YIG crystals. This increase is related to rare-earth impurities contaminating the YIG samples with a slight contribution caused by the coupling of spin waves to the spin system of the paramagnetic GGG substrate at the lowest temperatures.

Measurements of long-wavelength spin waves for the magnetic field in the Damon-Eshbach, backward-volume and forward-volume geometries of an yttrium iron garnet film

DOE PAGES

Bang, Wonbae; Lim, Jinho; Trossman, Jonathan; ...

2018-03-23

In this paper, we report systematic measurements of the dispersion of long wavelength spin waves for a wide range of wave vectors for the magnetic field along the three principal directions defining the forward volume, backward volume and Damon-Eshbach modes of a 9.72 μm thick film of an yttrium iron garnet obtained using lithographically patterned, multi-element, spatially resonant, antennas. Overall good agreement is found between the experimental data for the backward volume and Damon-Eshbach modes and the magnetostatic theory of Damon and Eshbach. Also, good agreement is found between the experimental data for the forward volume mode and the theorymore » of Damon and van de Vaart.« less

Measurements of long-wavelength spin waves for the magnetic field in the Damon-Eshbach, backward-volume and forward-volume geometries of an yttrium iron garnet film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Wonbae; Lim, Jinho; Trossman, Jonathan

In this paper, we report systematic measurements of the dispersion of long wavelength spin waves for a wide range of wave vectors for the magnetic field along the three principal directions defining the forward volume, backward volume and Damon-Eshbach modes of a 9.72 μm thick film of an yttrium iron garnet obtained using lithographically patterned, multi-element, spatially resonant, antennas. Overall good agreement is found between the experimental data for the backward volume and Damon-Eshbach modes and the magnetostatic theory of Damon and Eshbach. Also, good agreement is found between the experimental data for the forward volume mode and the theorymore » of Damon and van de Vaart.« less

Evaluation of Liver Biomarkers as Prognostic Factors for Outcomes to Yttrium-90 Radioembolization of Primary and Secondary Liver Malignancies.

PubMed

Henrie, Adam M; Wittstrom, Kristina; Delu, Adam; Deming, Paulina

2015-09-01

The objective of this study was to examine indicators of liver function and inflammation for prognostic value in predicting outcomes to yttrium-90 radioembolization (RE). In a retrospective analysis, markers of liver function and inflammation, biomarkers required to stage liver function and inflammation, and data regarding survival, tumor response, and progression after RE were recorded. Univariate regression models were used to investigate the prognostic value of liver biomarkers in predicting outcome to RE as measured by survival, tumor progression, and radiographic and biochemical tumor response. Markers from all malignancy types were analyzed together. A subgroup analysis was performed on markers from patients with metastatic colorectal cancer. A total of 31 patients received RE from 2004 to 2014. Median survival after RE for all malignancies combined was 13.6 months (95% CI: 6.7-17.6 months). Results from an exploratory analysis of patient data suggest that liver biomarkers, including albumin concentrations, international normalized ratio, bilirubin concentrations, and the model for end-stage liver disease score, possess prognostic value in predicting outcomes to RE.

Complex upper arm reconstruction using an antero-lateral thigh free flap after an extravasation of Yttrium-90-ibritumomab Tiuxetan: A case report and literature review.

PubMed

Baus, A; Keilani, C; Bich, C-S; Entine, F; Brachet, M; Duhamel, P; Amabile, J-C; Malfuson, J V; Bey, E

2018-04-01

Yttrium-90-Ibritumomab Tiuxetan (Zevalin ® ) is used in the treatment of non- Hodgkin's lymphoma. Extravasation is an iatrogenic complication that is fortunately rare. However, the treatment of this complication is often complex due to the risk of extensive skin necrosis and unpredictable evolution of localized irradiation. This vesicant drug requires emergency management when extravasation occured. Radiations burns have specificities. Therefore, wound coverage involves specific plastic surgical techniques. Here, we report the case of a man presenting a chronic and extensive skin necrosis of upper arm treated with an antero-lateral thigh free flap. Moreover, we compare our experience of Zevalin ® extravasation management to other past publications and propose recommendations to prevent this unacceptable complication. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Revised calibration of the Sm:SrB{sub 4}O{sub 7} pressure sensor using the Sm-doped yttrium-aluminum garnet primary pressure scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rashchenko, Sergey V., E-mail: rashchenko@igm.nsc.ru; Litasov, Konstantin D.; Novosibirsk State University, 630090 Novosibirsk

2015-04-14

The pressure-induced shift of Sm:SrB{sub 4}O{sub 7} fluorescence was calibrated in a quasi-hydrostatic helium medium up to 60 GPa using the recent Sm-doped yttrium-aluminum garnet primary pressure scale as a reference. The resulting calibration can be written as P = −2836/14.3 [(1 + Δλ/685.51){sup −14.3 }− 1]. Previous calibrations based on the internally inconsistent primary scales are revised, and, after appropriate correction, found to agree with the proposed one. The calibration extended to 120 GPa was also performed using corrected previous data and can be written as P = 4.20 Δλ (1 + 0.020 Δλ)/(1 + 0.036 Δλ)

Impact of 4-epi-oxytetracycline on the gut microbiota and blood metabolomics of Wistar rats

PubMed Central

Han, Hongxing; Xiao, Hailong; Zhang, Kai; Lu, Zhenmei

2016-01-01

The impact of 4-epi-oxytetracycline (4-EOTC), one of the main oxytetracycline (OTC) metabolites, on the gut microbiota and physiological metabolism of Wistar rats was analyzed to explore the dynamic alterations apparent after repeated oral exposure (0.5, 5.0 or 50.0 mg/kg bw) for 15 days as shown by 16S rRNA pyrosequencing and UPLC-Q-TOF/MS analysis. Both principal component analysis and cluster analysis showed consistently altered patterns with distinct differences in the treated groups versus the control groups. 4-EOTC treatment at 5.0 or 50.0 mg/kg increased the relative abundance of the Actinobacteria, specifically Bifidobacteriaceae, and improved the synthesis of lysophosphatidylcholine (LysoPC), as shown by the lipid biomarkers LysoPC(16:0), LysoPC(18:3), LysoPC(20:3), and LysoPC(20:4). The metabolomic analysis of urine samples also identified four other decreased metabolites: diacylglycerol, sphingomyelin, triacylglycerol, and phosphatidylglycerol. Notably, the significant changes observed in these biomarkers demonstrated the ongoing disorder induced by 4-EOTC. Blood and urine analysis revealed that residual 4-EOTC accumulated in the rats, even two weeks after oral 4-EOTC administration, ceased. Thus, through thorough analysis, it can be concluded that the alteration of the gut microbiota and disorders in blood metabolomics are correlated with 4-EOTC treatment. PMID:26976662

Impact of 4-epi-oxytetracycline on the gut microbiota and blood metabolomics of Wistar rats.

PubMed

Han, Hongxing; Xiao, Hailong; Zhang, Kai; Lu, Zhenmei

2016-03-15

The impact of 4-epi-oxytetracycline (4-EOTC), one of the main oxytetracycline (OTC) metabolites, on the gut microbiota and physiological metabolism of Wistar rats was analyzed to explore the dynamic alterations apparent after repeated oral exposure (0.5, 5.0 or 50.0 mg/kg bw) for 15 days as shown by 16S rRNA pyrosequencing and UPLC-Q-TOF/MS analysis. Both principal component analysis and cluster analysis showed consistently altered patterns with distinct differences in the treated groups versus the control groups. 4-EOTC treatment at 5.0 or 50.0 mg/kg increased the relative abundance of the Actinobacteria, specifically Bifidobacteriaceae, and improved the synthesis of lysophosphatidylcholine (LysoPC), as shown by the lipid biomarkers LysoPC(16:0), LysoPC(18:3), LysoPC(20:3), and LysoPC(20:4). The metabolomic analysis of urine samples also identified four other decreased metabolites: diacylglycerol, sphingomyelin, triacylglycerol, and phosphatidylglycerol. Notably, the significant changes observed in these biomarkers demonstrated the ongoing disorder induced by 4-EOTC. Blood and urine analysis revealed that residual 4-EOTC accumulated in the rats, even two weeks after oral 4-EOTC administration, ceased. Thus, through thorough analysis, it can be concluded that the alteration of the gut microbiota and disorders in blood metabolomics are correlated with 4-EOTC treatment.

Fast Determination of Yttrium and Rare Earth Elements in Seawater by Inductively Coupled Plasma-Mass Spectrometry after Online Flow Injection Pretreatment.

PubMed

Zhu, Zuhao; Zheng, Airong

2018-02-23

A method for daily monitoring of yttrium and rare earth elements (YREEs) in seawater using a cheap flow injection system online coupled to inductively coupled plasma-mass spectrometry is reported. Toyopearl AF Chelate 650M ® resin permits separation and concentration of YREEs using a simple external calibration. A running cycle consumed 6 mL sample and took 5.3 min, providing a throughput of 11 samples per hour. Linear ranges were up to 200 ng kg -1 except Tm (100 ng kg -1 ). The precision of the method was <6% (RSDs, n = 5), and recoveries ranged from 93% to 106%. Limits of detection (LODs) were in the range 0.002 ng kg -1 (Tm) to 0.078 ng kg -1 (Ce). Good agreement between YREEs concentrations in CASS-4 and SLEW-3 obtained in this work and results from other studies was observed. The proposed method was applied to the determination of YREEs in seawater from the Jiulong River Estuary and the Taiwan Strait.

Clinical and Histopathologic Assessment of Facial Melasma After Low-Fluence Q-Switched Neodymium-Doped Yttrium Aluminium Garnet Laser.

PubMed

Hofbauer Parra, Camila Anna; Careta, Mariana Figueroa; Valente, Neusa Yuriko Sakai; de Sanches Osório, Nuno Eduardo Guimaraes; Torezan, Luis Antonio Ribeiro

2016-04-01

Melasma is a frequent and difficult to treat skin disorder. Results of laser therapy are inconsistent. To determine the safety and efficacy of low-fluence Q-switched neodymium-doped yttrium aluminum garnet (QS Nd:YAG) laser for melasma treatment and assess recurrence rates and histopathologic findings before and after treatment. Twenty patients were treated with 10 weekly sessions of low-fluence 1064-nm QS Nd:YAG laser at 1-week intervals. The modified Melasma Area and Severity Index (mMASI) score was evaluated at baseline; 1 week; and 1, 3, and 6 months after treatment. Epidermal melanin quantification was performed on 10 biopsy samples and compared before and after treatment. All patients showed improvement by mMASI scores, range (21%-75%) compared with that at baseline. No permanent side effects occurred. The recurrence rate was 81%. By histopathology, a slight, nonsignificant (p = .305) decrease in melanin deposition was seen in all layers of the epidermis 1 week after the laser treatments ended. The results confirm the safety and effectiveness of low-fluence QS Nd:YAG laser for treating melasma; however, the high recurrence suggests poor long-term results when the laser is used as a monotherapy.

Two-photon imaging of formaldehyde in live cells and animals utilizing a lysosome-targetable and acidic pH-activatable fluorescent probe.

PubMed

Xie, Xilei; Tang, Fuyan; Shangguan, Xiaoyan; Che, Shiyi; Niu, Jinye; Xiao, Yongsheng; Wang, Xu; Tang, Bo

2017-06-13

Lyso-TPFP presents lysosomal targetability and an acidic pH-activatable response toward formaldehyde. Thus, it exclusively visualizes lysosomal formaldehyde and is immune against it in neutral cytosol and other organelles. In addition, two-photon fluorescence imaging endows Lyso-TPFP with the capability of in situ tracking formaldehyde in live cells and animals.

Light desorption from an yttrium neutralizer for Rb and Fr magneto-optical trap loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coppolaro, V.; Papi, N.; Khanbekyan, A.

2014-10-07

We present here the first evidence of photodesorption induced by low-intensity non-resonant light from an yttrium thin foil, which works as a neutralizer for Rb and Fr ions beam. Neutral atoms are suddenly ejected from the metal surface in a pulsed regime upon illumination with a broadband flash light and then released in the free volume of a pyrex cells. Here atoms are captured by a Magneto-Optical Trap (MOT), which is effectively loaded by the photodesorption. Loading times of the order of the flash rise time are measured. Desorption is also obtained in the continuous regime, by exploiting CW visiblemore » illumination of the metallic neutralizer surface. We demonstrate that at lower CW light intensities vacuum conditions are not perturbed by the photodesorption and hence the MOT dynamics remains unaffected, while the trap population increases thanks to the incoming desorbed atoms flux. Even with the Y foil at room temperature and hence with no trapped atoms, upon visible illumination, the number of trapped atoms reaches 10{sup 5}. The experimental data are then analyzed by means of an analytical rate equation model, which allows the analysis of this phenomenon and its dynamics and allows the determination of critical experimental parameters and the test of the procedure in the framework of radioactive Francium trapping. In this view, together with an extensive investigation of the phenomenon with {sup 85}Rb, the first demonstration of the photodesorption-aided loading of a {sup 210}Fr MOT is shown.« less

Recovery of Rare Earth Elements and Yttrium from Passive-Remediation Systems of Acid Mine Drainage.

PubMed

Ayora, Carlos; Macías, Francisco; Torres, Ester; Lozano, Alba; Carrero, Sergio; Nieto, José-Miguel; Pérez-López, Rafael; Fernández-Martínez, Alejandro; Castillo-Michel, Hiram

2016-08-02

Rare earth elements and yttrium (REY) are raw materials of increasing importance for modern technologies, and finding new sources has become a pressing need. Acid mine drainage (AMD) is commonly considered an environmental pollution issue. However, REY concentrations in AMD can be several orders of magnitude higher than in naturally occurring water bodies. With respect to shale standards, the REY distribution pattern in AMD is enriched in intermediate and valuable REY, such as Tb and Dy. The objective of the present work is to study the behavior of REY in AMD passive-remediation systems. Traditional AMD passive remediation systems are based on the reaction of AMD with calcite-based permeable substrates followed by decantation ponds. Experiments with two columns simulating AMD treatment demonstrate that schwertmannite does not accumulate REY, which, instead, are retained in the basaluminite residue. The same observation is made in two field-scale treatments from the Iberian Pyrite Belt (IPB, southwest Spain). On the basis of the amplitude of this process and on the extent of the IPB, our findings suggest that the proposed AMD remediation process can represent a modest but suitable REY source. In this sense, the IPB could function as a giant heap-leaching process of regional scale in which rain and oxygen act as natural driving forces with no energy investment. In addition to having environmental benefits of its treatment, AMD is expected to last for hundreds of years, and therefore, the total reserves are practically unlimited.

Study on the activated laser welding of ferritic stainless steel with rare earth elements yttrium

NASA Astrophysics Data System (ADS)

Wang, Yonghui; Hu, Shengsun; Shen, Junqi

2015-10-01

The ferritic stainless steel SUS430 was used in this work. Based on a multi-component activating flux, composed of 50% ZrO2, 12.09 % CaCO3, 10.43 % CaO, and 27.49 % MgO, a series of modified activating fluxes with 0.5%, 1%, 2%, 5%, 10%, 15%, and 20% of rare earth (RE) element yttrium (Y) respectively were produced, and their effects on the weld penetration (WP) and corrosion resistant (CR) property were studied. Results showed that RE element Y hardly had any effects on increasing the WP. In the FeCl3 spot corrosion experiment, the corrosion rates of almost all the samples cut from welded joints turned out to be greater than the parent metal (23.51 g/m2 h). However, there was an exception that the corrosion rate of the sample with 5% Y was only 21.96 g/m2 h, which was even better than parent metal. The further Energy Dispersive Spectrometer (EDS) test showed the existence of elements Zr, Ca, O, and Y in the molten slag near the weld seam while none of them were found in the weld metal, indicating the direct transition of element from activating fluxes to the welding seam did not exist. It was known that certain composition of activating fluxes effectively restrain the loss of Cr element in the process of laser welding, and as a result, the CR of welded joints was improved.

Activation of photodynamic therapy in vitro with Cerenkov luminescence generated from Yttrium-90 (Conference Presentation)

NASA Astrophysics Data System (ADS)

Hartl, Brad A.; Hirschberg, Henry; Marcu, Laura; Cherry, Simon R.

2016-03-01

Translation of photodynamic therapy to the clinical setting has primarily been limited to easily accessible and/or superficial diseases where traditional light delivery can be performed noninvasively. Cerenkov luminescence, as generated from medically relevant radionuclides, has been suggested as a means to deliver light to deeper tissues noninvasively in order to overcome this depth limitation. We report on the use of Cerenkov luminescence generated from Yttrium-90 as a means to active the photodynamic therapy process in monolayer tumor cell cultures. The current study investigates the utility of Cerenkov luminescence for activating both the clinically relevant aminolevulinic acid at 1.0 mM and also the more efficient photosensitizer TPPS2a at 1.2 µM. Cells were incubated with aminolevulinic acid for 6 hours prior to radionuclide addition, as well as additional daily treatments for three days. TPPS2a was delivered as a single treatment with an 18 hour incubation time before radionuclide addition. Experiments were completed for both C6 glioma cells and MDA-MB-231 breast tumor cells. Although aminolevulinic acid proved ineffective for generating a therapeutic effect at any activity for either cell line, TPPS2a produced at least a 20% therapeutic effect at activities ranging from 6 to 60 µCi/well for the C6 cell line. Current results demonstrate that it may be possible to generate a therapeutic effect in vivo using Cerenkov luminescence to activate the photodynamic therapy process with clinically relevant photosensitizers.

Crystal structure and phase transformations of calcium yttrium orthophosphate, Ca 3Y(PO 4) 3

NASA Astrophysics Data System (ADS)

Fukuda, Koichiro; Iwata, Tomoyuki; Niwa, Takahiro

2006-11-01

Crystal structure and phase transformations of calcium yttrium orthophosphate Ca 3Y(PO 4) 3 were investigated by X-ray powder diffraction, selected-area electron diffraction, transmission electron microscopy and optical microscopy. The high-temperature phase is isostructural with eulytite, cubic (space group I4¯3d) with a=0.983320(5) nm, V=0.950790(8) nm 3, Z=4 and D x=3.45 Mg m -3. The crystal structure was refined with a split-atom model, in which the oxygen atoms are distributed over two partially occupied sites. Below the stable temperature range of eulytite, the crystal underwent a martensitic transformation, which is accompanied by the formation of platelike surface reliefs. The inverted crystal is triclinic (space group P1) with a=1.5726(1) nm, b=0.84267(9) nm, c=0.81244(8) nm, α=109.739(4)°, β=90.119(5)°, γ=89.908(7)°, V=1.0134(1) nm 3, Z=4 and D x=3.24 Mg m -3. The crystal grains were composed of pseudo-merohedral twins. The adjacent twin domains were related by the pseudo-symmetry mirror planes parallel to {101¯} with the composition surface {101¯}. When the eulytite was cooled relatively slowly from the stable temperature range, the decomposition reaction of Ca 3Y(PO 4) 3→ β-Ca 3(PO 4) 2+YPO 4 occurred.

Treatment of café-au-lait macules with a high-fluenced 1064-nm Q-switched neodymium:yttrium aluminum garnet laser.

PubMed

Kim, Jiehoon; Hur, Hoon; Kim, Yu Ri; Cho, Sung Bin

2018-02-01

Café-au-lait macules (CALMs) are light to dark brown macules or patches of increased melanin concentration found along the dermoepidermal junction. Although many attempts to treat CALMs using various kinds of laser/light-based devices have been reported, CALMs remain refractory thereto with high recurrence rates. In this case series, we describe four patients with idiopathic CALMs that were effectively and safely treated with a non-ablative, high-fluenced, Q-switched (QS), 1064-nm neodymium:yttrium aluminum garnet (Nd:YAG) laser. The typical laser parameters for treating CALMs, including a spot size of 7-7.5 mm, a fluence of 2.4-2.5 J/cm 2 , and one to two passes until the appearance of mild erythema, but not petechiae, were utilized in this study over 12-24 treatment sessions at 2-week intervals. We suggest that high-fluenced QS 1064-nm Nd:YAG laser treatment can be used as an effective and alternative treatment modality for CALMs with minimal risk of side effects.

NBD-labelled phospholipid accelerates apolipoprotein C-II amyloid fibril formation but is not incorporated into mature fibrils

PubMed Central

Ryan, Timothy M.; Griffin, Michael D. W.; Bailey, Michael F.; Schuck, Peter; Howlett, Geoffrey J.

2014-01-01

Human apolipoprotein (apo) C-II is one of several lipid-binding proteins that self-assemble into fibrils and accumulate in disease-related amyloid deposits. A general characteristic of these amyloid deposits is the presence of lipids, known to modulate individual steps in amyloid fibril formation. ApoC-II fibril formation is activated by sub-micellar phospholipids but inhibited by micellar lipids. We examined the mechanism for the activation by sub-micellar lipids using the fluorescently-labelled, short-chain phospholipid, 1-dodecyl-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]-2-hydroxy-glycero-3-phosphocholine (NBD-lyso-12-PC). Addition of submicellar NBD-lyso-12-PC increased the rate of fibril formation by apoC-II approximately two-fold. Stopped flow kinetic analysis using fluorescence detection and low, non-fibril forming concentrations of apoC-II indicated NBD-Lyso-12-PC binds rapidly, in the millisecond timescale, followed by the slower formation of discrete apoC-II tetramers. Sedimentation velocity analysis showed NBD-Lyso-12-PC binds to both apoC-II monomers and tetramers at approximately 5 sites per monomer with an average dissociation constant of approximately 10 μM. Mature apoC-II fibrils formed in the presence of NBD-Lyso-12-PC were devoid of lipid indicating a purely catalytic role for sub-micellar lipids in the activation of apoC-II fibril formation. These studies demonstrate the catalytic potential of small amphiphilic molecules to control protein folding and fibril assembly pathways. PMID:21985034

Development of a High Precision Axial 3-D PET for Brain Imaging

NASA Astrophysics Data System (ADS)

Bolle, E.; Braem, A.; Casella, C.; Chesi, E.; Clinthorne, N.; Cochran, E.; De Leo, R.; Dissertori, G.; Djambazov, L.; Honscheid, K.; Huh, S.; Johnson, I.; Joram, C.; Kagan, H.; Lacasta, C.; Lustermann, W.; Meddi, F.; Nappi, E.; Nessi-Tedaldi, F.; Oliver, J. F.; Pauss, F.; Rafecas, M.; Renker, D.; Rudge, A.; Schinzel, D.; Schneider, T.; Séguinot, J.; Smith, S.; Solevi, P.; Stapnes, S.; Vilardi, I.; Weilhammer, P.

2009-12-01

We describe a PET device based on a novel method to extract the coordinates of the interaction point of the 511keV γ rays from 100 mm long and thin LYSO (Lutetium Yttrium OxyorthoSilicate) scintillator bars, positioned axially in the tomograph. The coordinate along the hit crystal is measured by using a hodoscope of Wave Length Shifting (WLS) plastic strips mounted perpendicularly to each plane of scintillators. As photodetectors, new Geiger mode Avalanche PhotoDetectors (G-APDs) with integrated electronics are being used to detect both the hit crystal in a block (x and y coordinates) and the interaction point in the crystal (z coordinate) through the light escaping from the crystal and transmitted to the WLS strips. In this way, the γ interaction point can be determined with a spatial resolution of few cubic millimeters down to a minimum deposited energy of about 50 keV, resulting in a volumetric precision very close to the limits imposed by the physics of the positron annihilation. The method allows to increase the detection efficiency without affecting the spatial resolution by adding scintillator planes in the radial direction. A demonstrator scanner, based on two matrices of 8 × 6 LYS crystals and 312 WLS strips, slotted in between the crystals, is under construction. Preliminary results from the feasibility studies of the various components will be presented.

Stress development in thin yttrium films on hard substrates during hydrogen loading

NASA Astrophysics Data System (ADS)

Dornheim, M.; Pundt, A.; Kirchheim, R.; Molen, S. J. v. d.; Kooij, E. S.; Kerssemakers, J.; Griessen, R.; Harms, H.; Geyer, U.

2003-06-01

Polycrystalline (0002)-textured yttrium (Y) films of 50-500 nm thickness on sapphire substrates were loaded electrolytically with hydrogen (H). The stresses which build up in these films were measured in situ using curvature measurements. The results are compared to the behavior of bulk Y-H. A linear elastic model is used to predict the behavior of clamped thin films. Basic properties of the bulk Y-H phase diagram and elastic constants resemble the measured values of the thin films. Compressive stress builds up during H-loading in the α-Y phase and in the (α-Y+β-YH2) two-phase field, showing an initial stress increase of -1.3 GPa per hydrogen concentration XH (compressive stress). While bulk Y-H samples are known to show a contraction in the β-YH2 phase during H loading, thin films show no evidence for such a contraction during the first loading cycle of the film. The stress remains constant in the bulk β-phase concentration range (ΔXH=0.1 H/Y). This is attributed to the narrow β-phase field (ΔXH=0.02 H/Y) of the thin film during the first loading. Only samples which have been kept at a hydrogen concentration of about 1.5 H/Y for weeks show tensile stress in the concentration range of the bulk β phase. Amazingly a stress increase of about +0.5 GPa/XH (tensile stress) is measured in the β+γ two-phase field. This is attributed to the smaller in-plane nearest-neighbor distance in the γ phase compared to the β phase. In the γ-phase field compressive stress is built up again, compensating the tensile stress. It increases by -1.3 GPa/XH. In total, the net stress in Y-H films remains comparably small. This could be a reason for the good mechanical stability of such Y-H switchable mirrors during H cycling.

Strong excitation of surface and bulk spin waves in yttrium iron garnet placed in a split ring resonator

NASA Astrophysics Data System (ADS)

Tay, Z. J.; Soh, W. T.; Ong, C. K.

2018-02-01

This paper presents an experimental study of the inverse spin Hall effect (ISHE) in a bilayer consisting of a yttrium iron garnet (YIG) and platinum (Pt) loaded on a metamaterial split ring resonator (SRR). The system is excited by a microstrip feed line which generates both surface and bulk spin waves in the YIG. The spin waves subsequently undergo spin pumping from the YIG film to an adjacent Pt layer, and is converted into a charge current via the ISHE. It is found that the presence of the SRR causes a significant enhancement of the mangetic field near the resonance frequency of the SRR, resulting in a significant increase in the ISHE signal. Furthermore, the type of spin wave generated in the system can be controlled by changing the external applied magnetic field angle (θH ). When the external applied magnetic field is near parallel to the microstrip line (θH = 0 ), magnetostatic surface spin waves are predominantly excited. On the other hand, when the external applied magnetic field is perpendicular to the microstrip line (θH = π/2 ), backward volume magnetostatic spin waves are predominantly excited. Hence, it can be seen that the SRR structure is a promising method of achieving spin-charge conversion, which has many advantages over a coaxial probe.

Microstructure and Texture Evolution in a Yttrium-Containing ZM31 Alloy: Effect of Pre- and Post-deformation Annealing

NASA Astrophysics Data System (ADS)

Tahreen, N.; Zhang, D. F.; Pan, F. S.; Jiang, X. Q.; Li, D. Y.; Chen, D. L.

2016-12-01

Microstructure and texture evolution of as-extruded ZM31 magnesium alloys with different amounts of yttrium (Y) during pre- and post-deformation annealing were examined with special attention given to the effect of Y on recrystallization. It was observed that the extruded ZM31 alloys exhibited a basal texture with the basal planes parallel to the extrusion direction (ED). The compression of the extruded alloys in the ED to a strain amount of 10 pct resulted in c-axes of hcp unit cells rotating toward the anti-compression direction due to the occurrence of extension twinning. Annealing of the extruded alloys altered the microstructure and texture, and the subsequent compression after annealing showed a relatively weak texture and a lower degree of twinning. A reverse procedure of pre-compression and subsequent annealing was found to further weaken the texture with a more scattered distribution of orientations and to lead to the vanishing of the original basal texture. With increasing Y content, both the extent of extension twinning during compression and the fraction of recrystallization during annealing decreased due to the role of Y present in the substitutional solid solution and in the second-phase particles, leading to a significant increase in the compressive yield strength.

Cyclometalation and coupling of a rigid 4,5-bis(imino)acridanide pincer ligand on yttrium.

PubMed

Wong, Edwin W Y; Emslie, David J H

2015-07-07

An extremely rigid NNN-donor proligand, 4,5-bis{(diphenylmethylene)amino}-2,7,9,9-tetramethylacridan, H[AIm2] was prepared in five steps starting from 5-methyl-2-aminobenzoic acid and 4-bromotoluene. Reaction of intensely orange H[AIm2] with LiCH2SiMe3 formed deep blue Li(x)[AIm2]x (x = 2 in the solid state), while reaction with [Y(CH2SiMe3)3(THF)2] (0.5 equiv.) afforded deep blue [Y(AIm2)(AIm)] (1; AIm = an AIm2 ligand cyclometalated at the ortho-position of one of the phenyl rings). Compound 1 slowly isomerizes to form green-brown 2, which contains a single trianionic, hexadentate ligand that features one amine, two imine, and three amido donors. The acridanide backbone and one imine group in each of the original AIm2 ligands is intact, but the two acridanide backbones are now linked by an isoindoline heterocycle. Yttrium in 2 is coordinated to six nitrogen donors and the ortho carbon of an isoindoline phenyl substituent. The intense colours of H[AIm2], Li(x)[AIm2]x and 1 were shown by TD-DFT calculations to arise from charge transfer transitions from the HOMO, which is localized on the acridanide ligand backbone, to the LUMO and LUMO+1, which are localized on the imine substituents. The conversion of 1 to 2 was studied by UV-Visible absorption spectroscopy and is first-order with a half-life of 7.8 hours at room temperature.

Study of the effects of adding Yttrium oxide particles in some physical, thermal, and mechanical properties of heat-curing acrylic resin

NASA Astrophysics Data System (ADS)

Khalil, Bassam I.; Gharkan, Mohammed R.; Ali, Ahmed H.

2018-05-01

Extensively use of hot-curing acrylic in prosthetic dentistry field, increase the needed to modifying its mechanical, thermal, and physical properties. In this work Yttrium oxide had added with different weight fractions, (5%, 10%, 15% and 20%), as reinforcement phase on purpose of developing these properties. Tensile strength, hardness, density, water adsorption, and thermal conductivity had been investigated for prepared composite specimens. The results show that the maximum tensile strength was at (10) % wt. of Y2O3 addition, (19) %more than that of plain acrylic, maximum hardness was at (15) % wt. of Y2O3 addition, (8.5) % more than that of plain acrylic, maximum density was at (20) % wt. of Y2O3 addition, (18.2) % more than that of plain acrylic, maximum decrease in water absorption was at (10) % wt. of Y2O3 addition, (29) % less than that of plain acrylic. Finally the maximum thermal conductivity was at (20) % wt. of Y2O3 addition, (16) % more than that of plain acrylic.

Effect of ultrasound treatment on the morpho-structural and luminescent characteristics of cerium doped yttrium silicate phosphors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muresan, L.E., E-mail: laura_muresan2003@yahoo.com; Cadis, A.I.; Perhaita, I.

Highlights: • Y{sub 2}SiO{sub 5}:Ce is prepared by gel combustion in ultrasound conditions (US). • Morpho-structural characteristics are revealed based on FTIR, SEM, XRD, BET. • Incorporation of Ce{sup 3+} in X1/X2 type centers depends on preparative conditions. • US treatment increases the luminescent performances up to 151%. - Abstract: Cerium activated yttrium silicate (Y{sub 2}SiO{sub 5}:Ce) phosphors were prepared by gel-combustion, using yttrium–cerium nitrate as oxidizer, aspartic acid as fuel and TEOS as source of silicon. Two modalities for samples preparation were approached namely: the classical gel-combustion and sonication gel-combustion. The ultrasound treatment during the gelling stage has amore » positive effect on the structural and luminescent characteristics of the final product. Therefore, a well crystallized single X2–Y{sub 2}SiO{sub 5} phase phosphor was obtained at 1200 °C. Based on FT-IR and XRD investigations, conversion of X1 to X2–Y{sub 2}SiO{sub 5} phases is observed as the firing temperature is varied (1100 °C, 1200 °C, 1300 °C 1400 °C). The ultrasound treatment leads to smaller particle size and enhances the luminescent performances up to 151% in comparison with samples prepared by classical way.« less

Picosecond 532-nm neodymium-doped yttrium aluminium garnet laser-a novel and promising modality for the treatment of café-au-lait macules.

PubMed

Artzi, Ofir; Mehrabi, Joseph N; Koren, Amir; Niv, Roni; Lapidoth, Moshe; Levi, Assi

2018-05-01

Café-au-lait macules (CALMs) present as benign hyperpigmented, well-circumscribed spots on the skin for which many patients seek treatment for aesthetic reasons. The objective of this study is to report our experience in treating CALMs using a picosecond 532-nm neodymium-doped yttrium aluminium garnet (PS 532 nm) laser. This is a retrospective case series of 16 patients with CALMs who were treated by a PS 532-nm laser (1-4 treatments, 4-8 weeks apart). Response as seen on clinical photographs was assessed by two independent dermatologists and graded on a scale of 0 (exacerbation) to 5 (95-100% improvement). Patient satisfaction and tolerance were documented at final visit. The results of 15 patients demonstrated significant improvement (average 3.43), and their satisfaction and tolerance levels were high. One patient had no response whatsoever to treatment. The PS 532-nm laser is a promising novel modality for the treatment of CALMs.

Altered activity of lysophospholipase D, which produces bioactive lysophosphatidic acid and choline, in serum from women with pathological pregnancy.

PubMed

Tokumura, A; Kume, T; Taira, S; Yasuda, K; Kanzaki, H

2009-05-01

Altered lipid metabolism is associated with human abnormal pregnancy, such as pre-eclampsia and preterm labor, and potentially leads to fetus loss. A causative factor for the onset and progress of the systemic multifactorial syndromes associated with the pathological pregnancy is oxidized low-density lipoprotein, an active identity of which was postulated to be lysophosphatidic acid (LPA). We previously found that LPA is produced extracellularly by plasma lysophospholipase D (lysoPLD) activity of autotaxin, a tumor cell motility-stimulating protein. In this study, a convenient assay based on the choline released from endogenous substrate or exogenous lysophosphatidylcholine (LPC) was used for comparison of serum lysoPLD activity among patients with normal and abnormal pregnancy. The serum choline-producing activity was found to be mainly due to autotaxin, and dependent on its dilution rate. There was some association between low dilution dependency of serum lysoPLD activity toward an exogenous LPC and high lysoPLD activity toward endogenous substrates in cases of patients with preterm labor and pre-eclampsia. However, there was no difference in the serum level of LPC between women with normal pregnancy and those with pathological pregnancy. These results indicate that production of bioactive LPA by lysoPLD activity is elevated by an unknown mechanism that may be related to increased availability of endogenous substrates LPC, but not its concentration in human serum. If the level of LPA in blood circulation is elevated in the pathological pregnancies in vivo, it may play a role in induction and/or progression of systemic vascular dysfunction seen patients with preterm labor or pre-eclampsia.

Consequences of a global enzyme shortage of agalsidase beta in adult Dutch Fabry patients.

PubMed

Smid, Bouwien E; Rombach, Saskia M; Aerts, Johannes M F G; Kuiper, Symen; Mirzaian, Mina; Overkleeft, Hermen S; Poorthuis, Ben J H M; Hollak, Carla E M; Groener, Johanna E M; Linthorst, Gabor E

2011-10-31

Enzyme replacement therapy is currently the only approved therapy for Fabry disease. From June 2009 on, viral contamination of Genzyme's production facility resulted in a worldwide shortage of agalsidase beta leading to involuntary dose reductions (approved dose 1 mg/kg/eow, reduced dose 0.5 mg/kg/m), or switch to agalsidase alpha (administered dose 0.2 mg/kg/eow). An assessment report from the European Medicines Agency (EMA) raised serious concerns about an increase in adverse events at lower dosages of agalsidase beta. We determined the influence of the shortage on clinical event incidence and the most sensitive biochemical marker (lysoGb3) in Dutch Fabry patients. The incidence of clinical events per person per year was calculated from start of agalsidase beta treatment until the shortage, and was compared to the incidence of clinical events during the shortage period. In addition, plasma lysoGb3, eGFR, quality of life (SF-36) and brief pain inventory (BPI) questionnaires were analysed. All thirty-five Dutch Fabry patients using agalsidase beta (17 males) were included. Mean clinical event incidence was unchanged: 0.15 events per person per year before versus 0.15 during the shortage (p = 0.68). In total 28 clinical events occurred in 14 patients during 4.6 treatment years, compared to 7 events in 6 patients during the 1.3 year shortage period. eGFR and BPI scores were not significantly altered. Two SF-36 subscales were significantly but minimally reduced in females. In males, lysoGb3 increased with a median of 8.1 nM (range 2.5-29.2) after 1 year of shortage (p = 0.001). Increases in lysoGb3 were found in both patients switching to agalsidase alpha and on a reduced agalsidase beta dose. Antibody status, treatment duration or clinical event incidence showed no clear correlation to lysoGb3 increases. No increase in clinical event incidence was found in the adult Dutch Fabry cohort during the agalsidase beta shortage. Increases in lysoGb3, however, suggest

Highly transparent and lower resistivity of yttrium doped ZnO thin films grown on quartz glass by sol-gel method

NASA Astrophysics Data System (ADS)

Kaur, Narinder; Sharma, Sanjeev K.; Kim, Deuk Young; Singh, Narinder

2016-11-01

We prepared highly transparent yttrium-doped ZnO (YZO) thin films on quartz glass by a sol-gel method, and then annealed them at 600 °C in vacuum. All samples showed hexagonal wurtzite structure with a preferential orientation along the (002) direction. We observed the average grain size of Y: 2 at% thin film to be in the range of 15-20 nm. We observed blue shift in the optical bandgap (3.29 eV→3.32 eV) by increasing the Y concentration (0-2 at%), due to increasing the number of electrons, and replacing the di-valent (Zn2+) with tri-valent (Y3+) dopants. Replacing the higher ionic radii (Y3+) with smaller ionic radii (Zn2+) expanded the local volume of the lattice, which reduced the lattice defects, and increased the intensity ratio of NBE/DLE emission (INBE/IDLE). We also observed the lowest (172 meV) Urbach energy of Y: 2 at% thin film, and confirmed the high structural quality. Incorporation of the appropriate Y concentration (2 at%) improved the crystallinity of YZO thin films, which led to less carrier scattering and lower resistivity.

Higher Temperature Thermal Barrier Coatings with the Combined Use of Yttrium Aluminum Garnet and the Solution Precursor Plasma Spray Process

NASA Astrophysics Data System (ADS)

Gell, Maurice; Wang, Jiwen; Kumar, Rishi; Roth, Jeffery; Jiang, Chen; Jordan, Eric H.

2018-04-01

Gas-turbine engines are widely used in transportation, energy and defense industries. The increasing demand for more efficient gas turbines requires higher turbine operating temperatures. For more than 40 years, yttria-stabilized zirconia (YSZ) has been the dominant thermal barrier coating (TBC) due to its outstanding material properties. However, the practical use of YSZ-based TBCs is limited to approximately 1200 °C. Developing new, higher temperature TBCs has proven challenging to satisfy the multiple property requirements of a durable TBC. In this study, an advanced TBC has been developed by using the solution precursor plasma spray (SPPS) process that generates unique engineered microstructures with the higher temperature yttrium aluminum garnet (YAG) to produce a TBC that can meet and exceed the major performance standards of state-of-the-art air plasma sprayed YSZ, including: phase stability, sintering resistance, CMAS resistance, thermal cycle durability, thermal conductivity and erosion resistance. The temperature improvement for hot section gas turbine materials (superalloys & TBCs) has been at the rate of about 50 °C per decade over the last 50 years. In contrast, SPPS YAG TBCs offer the near-term potential of a > 200 °C improvement in temperature capability.

Long-Pulsed 532-Nm Neodymium-Doped Yttrium Aluminium Garnet Laser for Treatment of Facial Plane Warts in 160 Yemeni Patients.

PubMed

Alshami, Mohammad Ali; Mohana, Mona Jameel; Alshami, Ahlam Mohammad

2016-11-01

Warts in general and plane warts in particular pose a therapeutic challenge for dermatologists. Many treatment modalities exist, with variable success rates, side effect profiles, and precautions. The long-pulsed 532-nm neodymium-doped yttrium aluminium garnet (LP Nd:YAG) laser has not been previously used for this indication. This study was conducted to assess the efficacy and safety of the LP Nd:YAG laser for treating facial plane warts. A total of 160 Yemeni patients (62 women, 98 men; age range, 5-55 years) were exposed to 1 laser treatment session with the following parameters: wavelength, 532 nm; pulse duration, 20 millisecond; spot size, 2 to 3 mm; and fluence, 25 J/cm. The end point was graying or whitening of the lesion. Color photographs were taken before and immediately after treatment and at follow-up visits 1, 4, and 16 weeks after the laser session. An overall clearance rate of 92% after only one session was achieved, with minimal and transient side effects. The LP Nd:YAG laser is safe and effective for treating facial plane warts, with a success rate of 92% after only one session.

[Determination of trace lead and iron in nickel chloride and manganese sulfate by flame atomic absorption spectrometry after coprecipitation with yttrium phosphate].

PubMed

Su, Yao-Dong; Zhu, Wen-Ying; Ma, Hong-Mei; Chen, Long-Wu

2006-09-01

Using yttrium phosphate as the coprecipitation collector for the separation and preconcentration of trace lead and iron in nickel chloride and manganese sulfate, flame atomic absorption spectrometric (FAAS) determination was described in the present paper. Coprecipitation parameters including the pH of the solution, and the amounts of YCl3 and H3 PO4 were discussed. It was found that lead and iron in nickel chloride could be coprecipitated quantitatively in the range of pH 3.0-4.0, and so could be lead in manganese sulfate. The detection limits (3sigma) of lead and iron in 20 mL solution were 1.63 x 10(-2) mg x L(-1) and 4.58 x 10(-2) mg x L(-1) respectively. In NiCl2 solution the standard addition recoveries for lead and iron were 100.91% and 99.73% respectively, and in MnSO4 solution the standard addition recoveries were 99.45% and 98.98% respectively. The method has eliminated the interference of matrix, and the result is satisfied.

Erbium-yttrium-aluminum-garnet laser irradiation ameliorates skin permeation and follicular delivery of antialopecia drugs.

PubMed

Lee, Woan-Ruoh; Shen, Shing-Chuan; Aljuffali, Ibrahim A; Li, Yi-Ching; Fang, Jia-You

2014-11-01

Alopecia usually cannot be cured because of the available drug therapy being unsatisfactory. To improve the efficiency of treatment, erbium-yttrium-aluminum-garnet (Er-YAG) laser treatment was conducted to facilitate skin permeation of antialopecia drugs such as minoxidil (MXD), diphencyprone (DPCP), and peptide. In vitro and in vivo percutaneous absorption experiments were carried out by using nude mouse skin and porcine skin as permeation barriers. Fluorescence and confocal microscopies were used to visualize distribution of permeants within the skin. Laser ablation at a depth of 6 and 10 μm enhanced MXD skin accumulation twofold to ninefold depending on the skin barriers selected. DPCP absorption showed less enhancement by laser irradiation as compared with MXD. An ablation depth of 10 μm could increase the peptide flux from zero to 4.99 and 0.33 μg cm(-2) h(-1) for nude mouse skin and porcine skin, respectively. The laser treatment also promoted drug uptake in the hair follicles, with DPCP demonstrating the greatest enhancement (sixfold compared with the control). The imaging of skin examined by microscopies provided evidence of follicular and intercellular delivery assisted by the Er-YAG laser. Besides the ablative effect of removing the stratum corneum, the laser may interact with sebum to break up the barrier function, increasing the skin delivery of antialopecia drugs. The minimally invasive, well-controlled approach of laser-mediated drug permeation offers a potential way to treat alopecia. This study's findings provide the basis for the first report on laser-assisted delivery of antialopecia drugs. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Fractional versus ablative erbium:yttrium-aluminum-garnet laser resurfacing for facial rejuvenation: an objective evaluation.

PubMed

El-Domyati, Moetaz; Abd-El-Raheem, Talal; Abdel-Wahab, Hossam; Medhat, Walid; Hosam, Wael; El-Fakahany, Hasan; Al Anwer, Mustafa

2013-01-01

Laser is one of the main tools for skin resurfacing. Erbium:yttrium-aluminum-garnet (Er:YAG) was the second ablative laser, after carbon dioxide, emitting wavelength of 2940 nm. Fractional laser resurfacing has been developed to overcome the drawbacks of ablative lasers. We aimed to objectively evaluate the histopathological and immunohistochemical effects of Er:YAG 2940-nm laser for facial rejuvenation (multiple sessions of fractional vs single session of ablative Er:YAG laser). Facial resurfacing with single-session ablative Er:YAG laser was performed on 6 volunteers. Another 6 were resurfaced using fractional Er:YAG laser (4 sessions). Histopathological (hematoxylin-eosin, orcein, Masson trichrome, and picrosirius red stains) and immunohistochemical assessment for skin biopsy specimens were done before laser resurfacing and after 1 and 6 months. Histometry for epidermal thickness and quantitative assessment for neocollagen formation; collagen I, III, and VII; elastin; and tropoelastin were done for all skin biopsy specimens. Both lasers resulted in increased epidermal thickness. Dermal collagen showed increased neocollagen formation with increased concentration of collagen types I, III, and VII. Dermal elastic tissue studies revealed decreased elastin whereas tropoelastin concentration increased after laser resurfacing. Neither laser showed significant difference between their effects clinically and on dermal collagen. Changes in epidermal thickness, elastin, and tropoelastin were significantly more marked after ablative laser. The small number of patients is a limitation, yet the results show significant improvement. Multiple sessions of fractional laser have comparable effects to a single session of ablative Er:YAG laser on dermal collagen but ablative laser has more effect on elastic tissue and epidermis. Copyright © 2012 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Effect of neodymium:yttrium-aluminum-garnet laser and fluoride on the acid demineralization of enamel.

PubMed

Braga, Sheila Regina Maia; de Oliveira, Elisabeth; Sobral, Maria Angela Pita

2017-02-01

The aim of the present study was to evaluate the protective effect of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser and acidic phosphate fluoride (APF) on enamel erosion caused by hydrochloric acid. Fifty human enamel specimens were distributed according to the following treatments (n = 10): untreated (control), APF (1.23%) 4 min, Nd:YAG laser (100 mJ, 1 W, 10 Hz, 141.5 J/cm 2 ), APF + Nd:YAG laser, and Nd:YAG laser + APF. For 14 days the specimens were submitted to erosive challenge: 5 min in 3 mL hydrochloric acid (0.01 M, pH 2.2), rinsed with distilled water, and stored in artificial saliva for 3 h. This cycle was repeated four times per day. The calcium (Ca) loss was determined in demineralizing solution by atomic emission spectroscopy, and superficial roughness (Ra) was measured before and after the erosive challenge. The mean Ca loss was (mg/L, ± standard deviation): control 12.74 ± 3.33, APF 1.71 ± 0.11, laser 1.64 ± 0.08, APF + laser 1.38 ± 0.08, and laser + APF 1.48 ± 0.07. Kruskal-Wallis test showed a significant difference between the control and other groups. APF + laser showed minor loss of Ca. After the erosive challenge, the APF + laser group showed Ra alteration. A significant reduction in tooth dissolution was observed after fluoride application combined with Nd:YAG irradiation. © 2015 Wiley Publishing Asia Pty Ltd.

Yttrium orthoaluminate nanoperovskite doped with Tm3+ ions as upconversion optical temperature sensor in the near-infrared region.

PubMed

Hernández-Rodriguez, M A; Lozano-Gorrín, A D; Lavín, V; Rodríguez-Mendoza, U R; Martín, I R

2017-10-30

The thermal sensing capability of the Tm 3+ -doped yttrium orthoaluminate nanoperovskite in the infrared range, synthetized by a sol-gel method, was studied. The temperature dependence of the infrared upconverted emission bands located at around 705 nm ( 3 F 2,3 → 3 H 6 ) and 800 nm ( 3 H 4 → 3 H 6 ) of YAP: Tm 3+ nanoperovskite under excitation at 1210 nm was analyzed from RT up to 425 K. Calibration of the optical sensor has been made using the fluorescence intensity ratio technique, showing a high sensitivity in the near-infrared compared to other trivalent rare-earth based optical sensors working in the same range. In addition, a second calibration procedure of the YAP: Tm 3+ optical sensor was performed by using the FIR technique on the emission band associated to the 3 H 4 → 3 H 6 transition in the physiological temperature range (293-333 K), showing a very high relative sensitivity compared with other rare-earth based optical temperature sensors working in the physiological range. Moreover, the main advantage compared with other optical sensors is that the excitation source and the upconverted emissions do not overlap, since they lie in different biological windows, thus allowing its potential use as an optical temperature probe in the near-infrared range for biological applications.

In-situ diagnostics for metalorganic chemical vapor deposition of yttrium barium copper oxide

NASA Astrophysics Data System (ADS)

Tripathi, Ashok Burton

A new stagnation flow MOCVD research reactor is described that is designed to serve as a testbed to develop tools for "intelligent" thin film deposition, such as in-situ sensors and diagnostics, control algorithms, and thin film growth models. The reactor is designed in particular for the deposition of epitaxial YBa2Cu3O 7-delta on MgO, although with minor modifications it would be suitable for deposition of any metal-oxide thin films. The reactor is specifically designed to permit closed-loop thermal and stoichiometric control of the film growth process. Closed-loop control of precursor flow rates is accomplished by using ultraviolet absorption spectroscopy on each precursor line. Also integrated into the design is a Fourier Transform Infrared (FTIR) spectroscopy system which collects real-time, in-situ infrared polarized reflectance spectra of the film as it grows. Numerical simulation was used extensively to optimize the fluid dynamics and heat transfer to provide uniform fluxes to the substrate. As a result, thickness uniformity across the substrate is typically within 3% from the center to the edge of the substrate. Experimental studies of thin films grown in the Y/Ba/Cu/O system have been carried out. The films have been characterized by Rutherford Backscattering Spectrometry and X-ray Diffraction. Results indicate c-axis oriented grains with pure 1:2:3 phase YBCO, good spatial uniformity, and a low degree of c-axis wobble. Experimental growth data is used in a gas phase and surface chemistry model to calculate sticking coefficients for yttrium oxide, barium oxide, and copper oxide on YBCO. In-situ FTIR and Coherent Gradient Sensing (CGS) analysis of growing films has been performed, yielding accurate substrate temperature, film thickness monitoring, and full-field, real-time curvature maps of the films. In addition, we have implemented CGS to obtain full-field in-situ images of local curvature during oxygenation and deoxygenation of YBCO films. An analysis

Infrared spectroscopy and upconversion luminescence behaviour of erbium doped yttrium (III) oxide phosphor

NASA Astrophysics Data System (ADS)

Dubey, Vikas; Tiwari, Ratnesh; Tamrakar, Raunak Kumar; Rathore, Gajendra Singh; Sharma, Chitrakant; Tiwari, Neha

2014-11-01

The paper reports upconversion luminescence behaviour and infra-red spectroscopic pattern of erbium doped yttrium (III) oxide phosphor. Sample was synthesized by solid state reaction method with variable concentration or erbium (0.5-2.5 mol%). The conventional solid state method is suitable for large scale production and eco-friendly method. The prepared sample was characterized by X-ray diffraction (XRD) technique. From structural analysis by XRD technique shows cubic structure of prepared sample with variable concentration of erbium and no impurity phase were found when increase the concentration of Er3+. Particle size was calculated by Scherer's formula and it varies from 67 nm to 120 nm. The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM) technique. The surface morphology of the sample shows good connectivity with grains as well as some agglomerates formation occurs in sample. The functional group analysis was done by Fourier transform infra-red technique (FTIR) analysis which confirm the formation of Y2O3:Er3+ phosphor was prepared. The results indicated that the Y2O3:Er3+ phosphors might have high upconversion efficiency because of their low vibrational energy. Under 980 nm laser excitation sample shows intense green emission at 555 nm and orange emission at 590 nm wavelength. For green emission transition occurs 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 for upconversion emissions. Excited state absorption and energy transfer process were discussed as possible upconversion mechanisms. The near infrared luminescence spectra was recorded. The upconversion luminescence intensity increase with increasing the concentration or erbium up to 2 mol% after that luminescence intensity decreases due to concentration quenching occurs. Spectrophotometric determinations of peaks are evaluated by Commission Internationale de I'Eclairage (CIE) technique. From CIE technique the dominant peak of from PL spectra shows

Fractional erbium-doped yttrium aluminum garnet laser-assisted drug delivery of hydroquinone in the treatment of melasma

PubMed Central

Badawi, Ashraf M; Osman, Mai Abdelraouf

2018-01-01

Background Melasma is a difficult-to-treat hyperpigmentary disorder. Ablative fractional laser (AFL)-assisted delivery of topically applied drugs to varied targets in the skin has been an area of ongoing study and research. Objective The objective of this study was to evaluate the efficacy and safety of fractional erbium-doped yttrium aluminum garnet (Er:YAG) laser as an assisted drug delivery for enhancing topical hydroquinone (HQ) permeation into the skin of melasma patients. Patients and methods Thirty female patients with bilateral melasma were randomly treated in a split-face controlled manner with a fractional Er:YAG laser followed by 4% HQ cream on one side and 4% HQ cream alone on the other side. All patients received six laser sessions with a 2-week interval. The efficacy of treatments was determined through photographs, dermoscopic photomicrographs and Melasma Area Severity Index (MASI) score, all performed at baseline and at 12 weeks of starting therapy. The patient’s level of satisfaction was also recorded. Results Er:YAG laser + HQ showed significantly better results (p<0.005) with regard to decrease in the degree of pigmentation as assessed on the 4-point scale than HQ alone. There was a significant decrease in MASI scores on Er:YAG laser + HQ side vs HQ side. Minor reversible side effects were observed on both sides. Conclusion AFL-assisted delivery of HQ is a safe and effective method for the treatment of melasma. PMID:29379308

Rapid resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry-based metabolomics approach to study the effects of jieduquyuziyin prescription on systemic lupus erythematosus.

PubMed

Ding, Xinghong; Hu, Jinbo; Wen, Chengping; Ding, Zhishan; Yao, Li; Fan, Yongsheng

2014-01-01

Jieduquyuziyin prescription (JP), a traditional Chinese medicine (TCM) prescription, has been widely used for the clinical treatment of systemic lupus erythematosus (SLE). However, the complex chemical constituents of JP and the multifactorial pathogenesis of SLE make research on the therapeutic mechanism of JP in SLE challenging. In this paper, a serum metabolomics approach based on rapid resolution liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (RRLC-Q-TOF/MS) was employed to acquire the metabolic characteristics of serum samples obtained from mice in the SLE model group, JP-treated group, prednisone acetate (PA)-treated group and control group. The orthogonal partial least squares (OPLS) was applied to recognize metabolic patterns, and an obvious separation of groups was obtained. Thirteen metabolites, namely, phosphatidylethanolamine (PE 20:3), hepoxilin B3, lyso- phosphatidylethanolamine (lyso-PE 22:6), 12S-hydroxypentaenoic acid (12S-HEPE), traumatic acid, serotonin, platelet-activating factor (PAF), phosphatidylcholine (PC 20:5),eicosapentaenoic acid (EPA), 12(S)-hydroxyei- cosatetraenoic acid (12S-HETE), 14-hydroxy docosahexaenoic acid (14-HDOHE), lyso-phosphatidylcholine (lyso-PC 20:4), and indole acetaldehyde, were identified and characterized as differential metabolites involved in the pathogenesis of SLE. After treatment with JP, the relative content of 12(S)-HETE, PAF, 12(S)-HEPE, EPA, PE (20:3), Lyso-PE(22:6), and 14-HDOHE were effectively regulated, which suggested that the therapeutic effects of JP on SLE may involve regulating disturbances to the metabolism of unsaturated fatty acid, tryptophan and phospholipid. This research also demonstrated that metabolomics is a powerful tool for researching complex disease mechanisms and evaluating the mechanism of action of TCM.

Interaction of the minocycline with extracelluar protein and intracellular protein by multi-spectral techniques and molecular docking

NASA Astrophysics Data System (ADS)

Fang, Qing; Wang, Yirun; Hu, Taoying; Liu, Ying

2017-02-01

The interaction of minocyeline (MNC) with extracelluar protein (lysozyme, LYSO) or intracellular protein (bovine hemoglobin, BHb) was investigated using multi-spectral techniques and molecular docking in vitro. Fluorescence studies suggested that MNC quenched LYSO/BHb fluorescence in a static mode with binding constants of 2.01 and 0.26 × 104 L•mol-1 at 298 K, respectively. The LYZO-MNC system was more easily influenced by temperature (298 and 310 K) than the BHb-MNC system. The thermodynamic parameters demonstrated that hydrogen bonds and van der Waals forces played the major role in the binding process. Based on the Förster theory of nonradiative energy transfer, the binding distances between MNC and the inner tryptophan residues of LYSO and BHb were calculated to be 4.34 and 3.49 nm, respectively. Furthermore, circular dichroism spectra (CD), Fourier transforms infrared (FTIR), UV-vis, and three-dimensional fluorescence spectra results indicated the secondary structures of LYSO and BHb were partially destroyed by MNC with the α-helix percentage of LYZO-MNC increased (17.8-28.6%) while that of BHb-MNC was decreased (41.6-39.6%). UV-vis spectral results showed these binding interactions could cause conformational and some micro-environmental changes of LYSO and BHb. In accordance with the results of molecular docking, In LYZO-MNC system, MNC was mainly bound in the active site hinge region where Trp-62 and Trp-63 are located, and in MNC-BHb system, MNC was close to the subunit α 1 of BHb, molecular docking analysis supported the thermodynamic results well. The work contributes to clarify the mechanism of MNC with two proteins at molecular level.

Lipidomics comparing DCD and DBD liver allografts uncovers lysophospholipids elevated in recipients undergoing early allograft dysfunction.

PubMed

Xu, Jin; Casas-Ferreira, Ana M; Ma, Yun; Sen, Arundhuti; Kim, Min; Proitsi, Petroula; Shkodra, Maltina; Tena, Maria; Srinivasan, Parthi; Heaton, Nigel; Jassem, Wayel; Legido-Quigley, Cristina

2015-12-04

Finding specific biomarkers of liver damage in clinical evaluations could increase the pool of available organs for transplantation. Lipids are key regulators in cell necrosis and hence this study hypothesised that lipid levels could be altered in organs suffering severe ischemia. Matched pre- and post-transplant biopsies from donation after circulatory death (DCD, n = 36, mean warm ischemia time = 2 min) and donation after brain death (DBD, n = 76, warm ischemia time = none) were collected. Lipidomic discovery and multivariate analysis (MVA) were applied. Afterwards, univariate analysis and clinical associations were conducted for selected lipids differentiating between these two groups. MVA grouped DCD vs. DBD (p = 6.20 × 10(-12)) and 12 phospholipids were selected for intact lipid measurements. Two lysophosphatidylcholines, LysoPC (16:0) and LysoPC (18:0), showed higher levels in DCD at pre-transplantation (q < 0.01). Lysophosphatidylcholines were associated with aspartate aminotransferase (AST) 14-day post-transplantation (q < 0.05) and were more abundant in recipients undergoing early allograft dysfunction (EAD) (p < 0.05). A receiver-operating characteristics (ROC) curve combining both lipid levels predicted EAD with 82% accuracy. These findings suggest that LysoPC (16:0) and LysoPC (18:0) might have a role in signalling liver tissue damage due to warm ischemia before transplantation.

Activation of PAF-synthesizing enzymes in rat brain stem slices after LTP induction in the medial vestibular nuclei.

PubMed

Francescangeli, Ermelinda; Grassi, Silvarosa; Pettorossi, Vito E; Goracci, Gianfrancesco

2002-11-01

LysoPAF acetyltransferase (lysoPAF-AT) and PAF-synthesizing phosphocholinetransferase (PAF-PCT) are the two enzymes which catalyze the final reactions for the synthesis of PAF. Their activities, assayed in the homogenate of rat brain stem slices and under their optimal conditions, increased 5 min after high frequency stimulation of vestibular afferents, inducing LTP in the medial vestibular nuclei. The activity of phosphatidylcholine-synthesizing phosphocholinetransferase, was not affected. Sixty minutes from the induction of LTP, PAF-PCT activity, but not that of lysoPAF-AT, was still significantly higher with respect to 5 min test stimulated control. We used AP-5 to verify whether this increase was strictly dependent upon LTP induction, which requires NMDA receptor activation. In AP-5 treated slices, lysoPAF-acetyltransferase and PAF-synthesizing phosphocholinetransferase activities increased, but they were reduced after high frequency stimulation under AP-5. In conclusion, we have demonstrated that the activities of PAF-synthesizing enzymes are activated soon after the induction of LTP and that this effect is linked to the activation of NMDA-receptors. We suggest that the enzyme activation by AP-5, preventing LTP, might be due to glutamate enhancement but, in neurons showing LTP and under normal conditions, the activation of potentiation mechanisms is critical for the enhancement of enzyme activities.

Update on lasers in urology 2014: current assessment on holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripter settings and laser fibers.

PubMed

Kronenberg, Peter; Traxer, Olivier

2015-04-01

The purpose of the study was to review the existing literature on holmium:yttrium-aluminum-garnet laser lithotripsy regarding lithotripter settings and laser fibers. An online search of current and past peer-reviewed literature on holmium laser lithotripsy was performed on several databases, including PubMed, SciElo, and Google Scholar. Relevant studies and original articles about lithotripter settings and laser fibers were examined, and the most important information is summarized and presented here. We examine how the choice of lithotripter settings and laser fibers influences the performance of holmium laser lithotripsy. Traditional laser lithotripter settings are analyzed, including pulse energy, pulse frequency, and power levels, as well as newly developed long-pulse modes. The impact of these settings on ablation volume, fragment size, and retropulsion is also examined. Advantages of small- and large-diameter laser fibers are discussed, and controversies are highlighted. Additionally, the influence of the laser fiber is examined, specifically the fiber tip preparation and the lithotripter settings' influence on tip degradation. Many technical factors influence the performance of holmium laser lithotripsy. Knowing and understanding these controllable parameters allows the urologist to perform a laser lithotripsy procedure safely, efficiently, and with few complications.

Hydrophilic interaction liquid chromatography-mass spectrometry of (lyso)phosphatidic acids, (lyso)phosphatidylserines and other lipid classes.

PubMed

Cífková, Eva; Hájek, Roman; Lísa, Miroslav; HolĿapek, Michal

2016-03-25

The goal of this work is a systematic optimization of hydrophilic interaction liquid chromatography (HILIC) separation of acidic lipid classes (namely phosphatidic acids-PA, lysophosphatidic acids-LPA, phosphatidylserines-PS and lysophosphatidylserines-LPS) and other lipid classes under mass spectrometry (MS) compatible conditions. The main parameters included in this optimization are the type of stationary phases used in HILIC, pH of the mobile phase, the type and concentration of mobile phase additives. Nine HILIC columns with different chemistries (unmodified silica, modified silica using diol, 2-picolylamine, diethylamine and 1-aminoanthracene and hydride silica) are compared with the emphasis on peak shapes of acidic lipid classes. The optimization of pH is correlated with the theoretical calculation of acidobasic equilibria of studied lipid classes. The final method using the hydride column, pH 4 adjusted by formic acid and the gradient of acetonitrile and 40 mmol/L of aqueous ammonium formate provides good peak shapes for all analyzed lipid classes including acidic lipids. This method is applied for the identification of lipids in real samples of porcine brain and kidney extracts. Copyright © 2016 Elsevier B.V. All rights reserved.

Internal photopumping of Nd3+ (2H9/2, 4F5/2) states in yttrium aluminum garnet by excitation transfer from oxygen deficiency centers and Fe3+ continuum emission

NASA Astrophysics Data System (ADS)

Hewitt, J. D.; Spinka, T. M.; Senin, A. A.; Eden, J. G.

2011-07-01

Photoexcitation of Nd3+ (2H9/2, 4F5/2) states by the broad (˜70 nm FWHM), near-infrared continuum provided by Fe3+ has been observed at 300 K in bulk yttrium aluminum garnet (YAG) crystals doped with trace concentrations (<50 ppm) of Fe, Cr, and Eu. Irradiation of YAG at 248 nm with a KrF laser, which excites the oxygen deficiency center (ODC) in YAG having peak absorption at ˜240 nm, culminates in ODC→Fe3+ excitation transfer and subsequent Fe3+ emission. This internal optical pumping mechanism for rare earth ions is unencumbered by the requirement for donor-acceptor proximity that constrains conventional Förster-Dexter excitation transfer in co-doped crystals.

The Effect of Neodymium: Yttrium Aluminum Garnet and Fractional Carbon Dioxide Lasers on Alopecia Areata: A Prospective Controlled Clinical Trial.

PubMed

Yalici-Armagan, Basak; Elcin, Gonca

2016-04-01

Effective treatment options for alopecia areata (AA) are missing. Whether lasers might be effective is a topic of debate. We aimed to evaluate whether neodymium: yttrium aluminum garnet (Nd:YAG) or fractional carbon dioxide lasers might stimulate the development of new hair. Thirty-two patients who had long-standing and treatment refractory diseases were recruited for the study. Three different patches on the scalp were selected, 1 of which served as control. The mean outcome measure was the hair count, which was calculated with the digital phototrichogram. Response was defined as at least 25% increase in the mean hair count at the treated patch compared with the control patch. At the end of the study, there was no statistically significant difference in the mean hair count for the 3 patches. In 7 of 32 patients (22%), an increase in the mean hair count was observed on the whole scalp including the control patch, which resulted in an improved Severity of Alopecia Tool (SALT) score. We have observed that Nd:YAG or fractional carbon dioxide lasers did not increase the mean hair count on the treated AA patches when compared with the control patch. However, an SALT score improvement in 22% of the patients suggested spontaneous remission.

Safety of Radioembolization with {sup 90}Yttrium Resin Microspheres Depending on Coiling or No-Coiling of Aberrant/High-Risk Vessels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paprottka, P. M., E-mail: philipp.paprottka@med.lmu.de, E-mail: philipp.paprottka@med.uni-muenchen.de; Paprottka, K. J., E-mail: karolin.paprottka@med.lmu.de; Walter, A., E-mail: alexandra.Walter@campus.lmu.de

2015-08-15

PurposeTo evaluate the safety of radioembolization (RE) with {sup 90}Yttrium ({sup 90}Y) resin microspheres depending on coiling or no-coiling of aberrant/high-risk vessels.Materials and MethodsEarly and late toxicity after 566 RE procedures were analyzed retrospectively in accordance with the National Cancer Institute’s Common Terminology Criteria for Adverse Events (CTCAE v3.0). For optimal safety, aberrant vessels were either coil embolized (n = 240/566, coiling group) or a more peripheral position of the catheter tip was chosen to treat right or left liver lobes (n = 326/566, no-coiling group).ResultsClinically relevant late toxicities (≥Grade 3) were observed in 1 % of our overall cohort. The no-coiling group had significantlymore » less “any” (P = 0.0001) or “clinically relevant” (P = 0.0003) early toxicity. There was no significant difference (P > 0.05) in delayed toxicity in the coiling versus the no-coiling group. No RE-induced liver disease was noted after all 566 procedures.ConclusionRE with {sup 90}Y resin microspheres is a safe and effective treatment option. Performing RE without coil embolization of aberrant vessels prior to treatment could be an alternative for experienced centers.« less

Oriented 1,2-dimyristoyl-sn-glycero-3-phosphorylcholine/ganglioside membranes: a Fourier transform infrared attenuated total reflection spectroscopic study. Band assignments; orientational, hydrational, and phase behavior; and effects of Ca2+ binding.

PubMed

Müller, E; Giehl, A; Schwarzmann, G; Sandhoff, K; Blume, A

1996-09-01

Fourier transform infrared (FTIR) attenuated total reflection (ATR) spectroscopy was used to elucidate the hydration behavior and molecular order of phospholipid/ganglioside bilayers. We examined dry and hydrated films of the gangliosides GM1, deacetyl-GM1, lyso-GM1, deacetyllyso-GM1, and GM3 and oriented mixed films of these gangliosides with 1,2-dimyristoyl-sn-glycero-3-phosphorylcholine (DMPC) using polarized light. Analysis of the amide I frequencies reveals that the amide groups are involved in intermolecular interactions via hydrogen bonds of varying strengths. The tilt angle of the acyl chains of the lipids in mixed films was determined as a function of ganglioside structure. Deacetylation of the sialic acid in the headgroup has a stronger influence on the tilt angle than the removal of the ganglioside fatty acid. The phase behavior was examined by FTIR ATR spectroscopy and by differential scanning calorimetry (DSC) measurements on lipid suspensions. At the same molar concentration, lyso-gangliosides have less effect on changes of transition temperature compared to the double-chain analogs. Distinct differences in the amide band shapes were observed between mixtures with lyso-gangliosides and normal double-chain gangliosides. Determined from the dicroic ratio RATR, the orientation of the COO- group in all DMPC/ganglioside mixtures was found to be relatively fixed with respect to the membrane normal. In 4:1 mixtures of DMPC with GM1 and deacetyl-GM1, the binding of Ca2+ leads to a slight decrease in chain tilt in the gel phase, probably caused by a dehydration of the membrane-water interface. In mixtures of DMPC with GM3 and deacetyl-lyso-GM1, a slight increase in chain tilt is observed. The chain tilt in DMPC/lyso-GM1 mixtures is unchanged. Analysis of the COO- band reveals that Ca2+ does not bind to the carboxylate group of the sialic acid of GM1 and deacetyl-GM1, the mixtures in which a decrease in chain tilt was observed. Binding to the sialic acid was

Analog electro-optical readout of SiPMs achieves fast timing required for time-of-flight PET/MR

PubMed Central

Bieniosek, MF

2015-01-01

The design of combined positron emission tomography/magnetic resonance (PET/MR) systems presents a number of challenges to engineers, as it forces the PET system to acquire data in space constrained environment that is sensitive to electro-magnetic interference and contains high static, radio frequency (RF) and gradient fields. In this work we validate fast timing performance of a PET scintillation detector using a potentially very compact, very low power, and MR compatible readout method in which analog silicon photomultipliers (SiPM) signals are transmitted optically away from the MR bore with little or even no additional readout electronics. This analog ‘electro-optial’ method could reduce the entire PET readout in the MR bore to two compact, low power components (SiPMs and lasers). Our experiments show fast timing performance from analog electro-optical readout with and without pre-amplification. With 3mm × 3mm × 20mm lutetium-yttrium oxyorthosilicate (LYSO) crystals and Excelitas SiPMs the best two-sided fwhm coincident timing resolution achieved was 220 +/- 3ps in electrical mode, 230 +/- 2ps in electro-optical with preamp mode, and 253 +/- 2ps in electro-optical without preamp mode. Timing measurements were also performed with Hamamatsu SiPMs and 3mm × 3mm × 5mm crystals. In the future the timing degradation seen can be further reduced with lower laser noise or improvements SiPM rise time or gain. PMID:25905626

Robust diamond-like Fe-Si network in the zero-strain Na xFeSiO 4 cathode

DOE PAGES

Ye, Zhuo; Zhao, Xin; Li, Shouding; ...

2016-07-14

Sodium orthosilicates Na 2 MSiO 4 ( M denotes transition metals) have attracted much attention due to the possibility of exchanging two electrons per formula unit. In this work, we report a group of sodium iron orthosilicates Na 2FeSiO 4. Their crystal structures are characterized by a diamond-like Fe-Si network. The Fe-Si network is quite robust against the charge/discharge process, which explains the high structural stability observed in experiment. Furthermore, using the density functional theory within the GGA + U framework and X-ray diffraction studies, the crystal structures and structural stabilities during the sodium extraction/re-insertion process are systematically investigated.

Consequences of a global enzyme shortage of agalsidase beta in adult Dutch Fabry patients

PubMed Central

2011-01-01

Background Enzyme replacement therapy is currently the only approved therapy for Fabry disease. From June 2009 on, viral contamination of Genzyme's production facility resulted in a worldwide shortage of agalsidase beta leading to involuntary dose reductions (approved dose 1 mg/kg/eow, reduced dose 0.5 mg/kg/m), or switch to agalsidase alpha (administered dose 0.2 mg/kg/eow). An assessment report from the European Medicines Agency (EMA) raised serious concerns about an increase in adverse events at lower dosages of agalsidase beta. We determined the influence of the shortage on clinical event incidence and the most sensitive biochemical marker (lysoGb3) in Dutch Fabry patients. Methods The incidence of clinical events per person per year was calculated from start of agalsidase beta treatment until the shortage, and was compared to the incidence of clinical events during the shortage period. In addition, plasma lysoGb3, eGFR, quality of life (SF-36) and brief pain inventory (BPI) questionnaires were analysed. Results All thirty-five Dutch Fabry patients using agalsidase beta (17 males) were included. Mean clinical event incidence was unchanged: 0.15 events per person per year before versus 0.15 during the shortage (p = 0.68). In total 28 clinical events occurred in 14 patients during 4.6 treatment years, compared to 7 events in 6 patients during the 1.3 year shortage period. eGFR and BPI scores were not significantly altered. Two SF-36 subscales were significantly but minimally reduced in females. In males, lysoGb3 increased with a median of 8.1 nM (range 2.5 - 29.2) after 1 year of shortage (p = 0.001). Increases in lysoGb3 were found in both patients switching to agalsidase alpha and on a reduced agalsidase beta dose. Antibody status, treatment duration or clinical event incidence showed no clear correlation to lysoGb3 increases. Conclusions No increase in clinical event incidence was found in the adult Dutch Fabry cohort during the agalsidase beta shortage

Electric field tuning of magnetism in heterostructure of yttrium iron garnet film/lead magnesium niobate-lead zirconate titanate ceramic

NASA Astrophysics Data System (ADS)

Lian, Jianyun; Ponchel, Freddy; Tiercelin, Nicolas; Chen, Ying; Rémiens, Denis; Lasri, Tuami; Wang, Genshui; Pernod, Philippe; Zhang, Wenbin; Dong, Xianlin

2018-04-01

In this paper, the converse magnetoelectric (CME) effect by electric field tuning of magnetization in an original heterostructure composed of a polycrystalline yttrium iron garnet (YIG) film and a lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramic is presented. The magnetic performances of the YIG films with different thicknesses under a DC electric field applied to the PMN-PZT ceramics and a bias magnetic field are investigated. All the magnetization-electric field curves are found to be in good agreement with the butterfly like strain curve of the PMN-PZT ceramic. Both the sharp deformation of about 2.5‰ of PMN-PZT and the easy magnetization switching of YIG are proposed to be the reasons for the strongest CME interaction in the composite at the small electric coercive field of PMN-PZT (4.1 kV/cm) and the small magnetic coercive field of YIG (20 Oe) where the magnetic susceptibility reaches its maximum value. A remarkable CME coefficient of 3.1 × 10-7 s/m is obtained in the system with a 600 nm-thick YIG film. This heterostructure combining multiferroics and partially magnetized ferrite concepts is able to operate under a small or even in the absence of an external bias magnetic field and is more compact and power efficient than the traditional magnetoelectric devices.

Pulmonary involvement in Fabry disease: effect of plasma globotriaosylsphingosine and time to initiation of enzyme replacement therapy.

PubMed

Franzen, Daniel; Haile, Sarah R; Kasper, David C; Mechtler, Thomas P; Flammer, Andreas J; Krayenbühl, Pierre A; Nowak, Albina

2018-01-01

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by mutations of GLA gene leading to reduced α-galactosidase activity and resulting in a progressive accumulation of globotriaosylceramide (Gb3) and its deacylated derivative, globotriaosyl-sphingosine (Lyso-Gb3). Plasma Lyso-Gb3 levels serve as a disease severity and treatment monitoring marker during enzyme replacement therapy (ERT). Adult patients with AFD who had yearly pulmonary function tests between 1999 and 2015 were eligible for this observational study. Primary outcome measures were the change in z-score of forced expiratory volume in the first second (FEV 1 ) and FEV 1 /FVC over time. Plasma Lyso-Gb3 levels and the age of ERT initiation were investigated for their association with lung function decline. Fifty-three patients (42% male, median (range) age at diagnosis of AFD 34 (6-61) years in men, 34 (13-67) in women) were included. The greatest decrease of FEV 1 /FVC z-scores was observed in Classic men (-0.048 per year, 95% CI -0.081 to -0.014), compared with the Later-Onset men (+0.013,95% CI -0.055 to 0.082), Classic women (-0.008, 95% CI -0.035 to +0.020) and Later-Onset women (-0.013, 95% CI -0.084 to +0.058). Cigarette smoking (P=0.022) and late ERT initiation (P=0.041) were independently associated with faster FEV 1 decline. FEV 1 /FVC z-score decrease was significantly reduced after initiation of ERT initiation (-0.045 compared with -0.015, P=0.014). Furthermore, there was a trend towards a relevant influence of Lyso-Gb3 (P=0.098) on airflow limitation with age. Early ERT initiation seems to preserve pulmonary function. Plasma Lyso-Gb3 is maybe a useful predictor for airflow limitation. Classic men need a closer monitoring of the lung function.

Placental MFSD2a transporter is related to decreased DHA in cord blood of women with treated gestational diabetes.

PubMed

Prieto-Sánchez, María T; Ruiz-Palacios, María; Blanco-Carnero, José E; Pagan, Ana; Hellmuth, Christian; Uhl, Olaf; Peissner, Wolfgang; Ruiz-Alcaraz, Antonio J; Parrilla, Juan J; Koletzko, Berthold; Larqué, Elvira

2017-04-01

Maternal-fetal transfer of docosahexaenoic acid (DHA) is impaired by gestational diabetes mellitus (GDM), but the underlying mechanisms are still unknown. MFSD2a was recently recognized as a lyso-phospholipid (lyso-PL) transporter that facilitates DHA accretion in brain. The role of this transporter in placenta is uncertain. We evaluated effects of GDM and its treatment (diet or insulin) on phospholipid species, fatty acid profile in women, cord blood and placental fatty acid carriers. Prospective observational study of pregnant women recruited in the third trimester (25 controls, 23 GDM-diet, 20 GDM-insulin). Fetal ultrasound was performed at gestational week 38. At delivery, maternal and neonatal anthropometry was performed, and fatty acids in total lipids and phospholipid species were analyzed in placenta, maternal and venous cord blood. Western-blot analyses were performed for placental fatty acid carriers. Fetal abdominal circumference z-score at 38 weeks tended to higher values in GDM (P = 0.071), pointing toward higher fetal fat accretion in these babies. DHA percentage in cord serum total lipids (P = 0.029) and lyso-PL (P = 0.169) were reduced in GDM. Placental MFSD2a was reduced in both GDM groups and was positively correlated to DHA values in cord serum total lipids (r = 0.388, P = 0.003). Among established placental lipid carriers, only FATP4 was correlated to DHA concentration in placental lyso-PL. In all compartments, DHA percentage was inversely correlated to fetal abdominal circumference. In offspring of women with GDM treated either with diet or insulin, higher fetal fat accretion and lower placental MFSD2a contribute to reduce DHA availability. Lyso-PL appear to contribute to materno-fetal DHA transport. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Expression of orphan G-protein coupled receptor GPR174 in CHO cells induced morphological changes and proliferation delay via increasing intracellular cAMP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugita, Kazuya; Yamamura, Chiaki; Tabata, Ken-ichi

2013-01-04

Highlights: Black-Right-Pointing-Pointer Expression of GPR174 in CHO cells induces morphological changes and proliferation delay. Black-Right-Pointing-Pointer These are due to increase in intracellular cAMP concentration. Black-Right-Pointing-Pointer Lysophosphatidylserine was identified to stimulate GPR174 leading to activate ACase. Black-Right-Pointing-Pointer The potencies of fatty acid moiety on LysoPS were oleoyl Greater-Than-Or-Slanted-Equal-To stearoyl > palmitoyl. Black-Right-Pointing-Pointer We propose that GPR174 is a lysophosphatidylserine receptor. -- Abstract: We established cell lines that stably express orphan GPCR GPR174 using CHO cells, and studied physiological and pharmacological features of the receptor. GPR174-expressing cells showed cell-cell adhesion with localization of actin filaments to cell membrane, and revealed significant delaymore » of cell proliferation. Since the morphological changes of GPR174-cells were very similar to mock CHO cells treated with cholera toxin, we measured the concentration of intracellular cAMP. The results showed the concentration was significantly elevated in GPR174-cells. By measuring intracellular cAMP concentration in GPR174-cells, we screened lipids and nucleotides to identify ligands for GPR174. We found that lysophosphatidylserine (LysoPS) stimulated increase in intracellular cAMP in a dose-dependent manner. Moreover, phosphorylation of Erk was elevated by LysoPS in GPR174 cells. These LysoPS responses were inhibited by NF449, an inhibitor of G{alpha}{sub s} protein. These results suggested that GPR174 was a putative LysoPS receptor conjugating with G{alpha}{sub s}, and its expression induced morphological changes in CHO cells by constitutively activating adenylyl cycles accompanied with cell conjunctions and delay of proliferation.« less

Inhibitory effects of palmitoylcarnitine and lysophosphatidylcholine on the sodium current of cardiac ventricular cells.

PubMed

Sato, T; Kiyosue, T; Arita, M

1992-01-01

We investigated the effects of ischemia-related amphipathic compounds, palmitoylcarnitine (PamCar, 0.5-50 microM) and lysophosphatidylcholine (lysoPtdCho, 5-50 microM) on sodium current (INa) of guinea-pig ventricular myocytes. The cells were perfused with low-Na+ (60 mM) Tyrode's solution, and Ca2+ and K+ currents were blocked by external Co2+ (3 mM) and internal Cs+ (140 mM), respectively. INa was elicited by depolarizing voltage steps from a holding potential of -100 mV at a temperature of 33 degrees C. PamCar (5 microM) decreased the peak INa (attained at -20 mV or -30 mV) from 6.1 +/- 2.1 nA to 3.9 +/- 1.4 nA (n = 11), or by 36.1% within 2 min, and shifted the curve of steady-state INa inactivation by 5.4 mV in the positive direction (from -76.3 +/- 4.6 mV, control to -70.9 +/- 4.0 mV, in PamCar, n = 4). Partial restoration of the amplitude and the shift of the steady-state inactivation curve of INa was attained after washout of PamCar. In contrast, lysoPtdCho at concentrations over 10 microM irreversibly depressed the INa within 0.5-3 min and the reduction of INa was followed by cell contracture or cell death (n = 9). The survival time, defined as a period from the start of lysoPtdCho application to the time of the last successful recording of the INa (before evolution of sudden changes in the holding current), depended on the concentrations of lysoPtdCho. Both PamCar and lysoPtdCho retarded the time course of activation and inactivation of INa.(ABSTRACT TRUNCATED AT 250 WORDS)

Does ErbiumiYttrium-Aluminum-Garnet Laser to Enamel improve the Performance of Etch-and-rinse and Universal Adhesives?

PubMed

De Jesus Tavarez, Rudys R; Rodrigues, Lorrany Lc; Diniz, Ana C; Lage, Lucas M; Torres, Carlos Rg; Bandeca, Matheus C; Firoozmand, Leily M

2018-03-01

This study aims to evaluate the effect of erbium: Yttrium-aluminum-garnet (Er:YAG) laser irradiation on the enamel microshear bond strength (μSBS), followed by the utilization of etch-and-rinse and universal adhesive systems. A total of 32 molars were sectioned in the mesiodistal direction producing 64 samples that were randomized into two groups (n = 32): single bond 2 (SB2) (etch-and-rinse system; 3M), SB universal (SBU) (universal etching system; The SB2 and SBU groups were then divided into two subgroups (n = 16): (i) enamel was irradiated with an Er:YAG laser (λ = 2.94 μm, 60 mJ, 10 Hz), and (ii) enamel served as a control. The samples were restored with TPH3 (Dentsply), stored in artificial saliva for 24 hours, and subjected to a micro-shear test. Kruskal-Wallis (p < 0.05) and Mann-Whitney U tests indicated no significant differences in uSBS between the groups, and the fractures were predominately at the resin-enamel interface. The previous irradiation of enamel with Er:YAG laser does not interfere with the performance of simplified two-step etch-and-rinse and universal adhesive systems. The increasing use of Er:YAG laser is important to evaluate the influence of this irradiation on the adhesion of restorative materials. Thus, to obtain the longevity of the restorative procedures, it is necessary to know the result of the association of the present adhesive systems to the irradiated substrate.

Efficacy and safety of erbium-doped yttrium aluminium garnet fractional resurfacing laser for treatment of facial acne scars.

PubMed

Nirmal, Balakrishnan; Pai, Sathish B; Sripathi, Handattu; Rao, Raghavendra; Prabhu, Smitha; Kudur, Mohan H; Nayak, Sudhir U K

2013-01-01

Treatment of acne scars with ablative fractional laser resurfacing has given good improvement. But, data on Indian skin are limited. A study comparing qualitative, quantitative, and subjective assessments is also lacking. Our aim was to assess the improvement of facial acne scars with Erbium-doped Yttrium Aluminium Garnet (Er:YAG) 2940 nm fractional laser resurfacing and its adverse effects in 25 patients at a tertiary care teaching hospital. All 25 patients received four treatment sessions with Er:YAG fractional laser at 1-month interval. The laser parameters were kept constant for each of the four sittings in all patients. Qualitative and quantitative assessments were done using Goodman and Barron grading. Subjective assessment in percentage of improvement was also documented 1 month after each session. Photographs were taken before each treatment session and 1 month after the final session. Two unbiased dermatologists performed independent clinical assessments by comparing the photographs. The kappa statistics was used to monitor the agreement between the dermatologists and patients. Most patients (96%) showed atleast fair improvement. Rolling and superficial box scars showed higher significant improvement when compared with ice pick and deep box scars. Patient's satisfaction of improvement was higher when compared to physician's observations. No serious adverse effects were noted with exacerbation of acne lesions forming the majority. Ablative fractional photothermolysis is both effective and safe treatment for atrophic acne scars in Indian skin.Precise evaluation of acne scar treatment can be done by taking consistent digital photographs.

Long-pulsed 1064-nm neodymium:yttrium-aluminum-garnet laser treatment for refractory warts on hands and feet.

PubMed

Kimura, Utako; Takeuchi, Kaori; Kinoshita, Ayako; Takamori, Kenji; Suga, Yasushi

2014-03-01

Common warts (verruca vulgaris) are the most commonly seen benign cutaneous tumors. However, warts in the hands and feet regions often respond poorly to treatment, some are resistant to more than 6 months of treatment with currently available modalities, including cryotherapy, being defined as refractory warts. We investigated the usefulness of long-pulsed neodymium:yttrium-aluminum-garnet (LP-Nd:YAG) treatment for refractory warts. The clinical trial was conducted on 20 subjects (11 male, nine female) with a total of 34 lesions (periungual/subungual areas, plantar areas, fingers and/or toes). All the subjects suffered from refractory warts despite conventional treatments for more than 6 months. The patients were administrated up to six sessions of treatment, at intervals of 4 weeks between sessions, with an LP-Nd:YAG at a spot size of 5 mm, pulse duration of 15 msec and fluence of 150-185 J/cm(2) . Evaluation of the treatment results at 24 weeks after the initial treatment showed complete clearance of the refractory warts in 56% of the patients. Histological evaluation showed separation of the dermis and epidermis at the basement membrane with coagulated necrosis of the wart tissue in the lower epidermis, as well as coagulation and destruction of the blood vessels in the papillary dermis following the laser irradiation. No scarring, post-hyperpigmentary changes or serious adverse events were documented. Our preliminary results show that LP-Nd:YAG treatments are safe and effective for refractory warts of hands and feet, causing minimal discomfort, and is a viable treatment alternative. © 2014 Japanese Dermatological Association.

The group separation of the rare-earth elements and yttrium from geologic materials by cation-exchange chromatography

USGS Publications Warehouse

Crock, J.G.; Lichte, F.E.; Wildeman, T.R.

1984-01-01

Demand is increasing for the determination of the rare-earth elements (REE) and yttrium in geologic materials. Due to their low natural abundance in many materials and the interferences that occur in many methods of determination, a separation procedure utilizing gradient strong-acid cation-exchange chromatography is often used to preconcentrate and isolate these elements from the host-rock matrix. Two separate gradient strong-acid cation-exchange procedures were characterized and the major elements as well as those elements thought to provide the greatest interference for the determination of the REE in geologic materials were tested for separation from the REE. Simultaneous inductively coupled argon plasma-atomic emission spectroscopy (ICAP-AES) measurements were used to construct the chromatograms for the elution studies, allowing the elution patterns of all the elements of interest to be determined in a single fraction of eluent. As a rock matrix, U.S. Geological Survey standard reference BCR-1 basalt was digested using both an acid decomposition procedure and a lithium metaborate fusion. Hydrochloric and nitric acids were tested as eluents and chromatograms were plotted using the ICAP-AES data; and we observed substantial differences in the elution patterns of the REE and as well as in the solution patterns of Ba, Ca, Fe and Sr. The nitric acid elution required substantially less eluent to elute the REE and Y as a group when compared to the hydrochloric acid elution, and provided a clearer separation of the REE from interfering and matrix elements. ?? 1984.

A Comparative Histological Study of Bone Healing in Rat Calvarial Defect Using the Erbium-Doped Yttrium Aluminum Garnet Laser and Rotary Instruments

NASA Astrophysics Data System (ADS)

Jung, Mi-Kyung; Kim, Su-Gwan; Oh, Ji-Su; Jin, Seung-Chan; Lee, Sook-Young; Jang, Eun-Sook; Piao, Zheng-Gang; Lim, Sung-Chul; Jeong, Mi-Ae

2012-01-01

Erbium-doped yttrium aluminum garnet (Er:YAG) lasers have been used in dentistry for cutting bone and removal of caries. The purpose of this study was to evaluate the bone healing in a skull defect prepared in rats using various instruments including Er:YAG laser. The 7 mm calvarial defects were created in 45 rats and 45 rats were divided into three groups (n = 15): a high-speed rotation engine with carbide round bur (2-mm diameter), a low-speed rotation engine with carbide round bur (2-mm diameter), and an Er:YAG laser. Specimens obtained after 3 days or 4 or 8 weeks were submitted for histological analysis. Three days after surgery, no bone formation had occurred in any of the groups. Four weeks after surgery, 90 ±8.16% new bone formation was observed in the high-speed group, and 8 weeks after surgery, 100 ±0% new bone formation was observed in the low- and high-speed groups. There were significant differences among the periods after surgery, but no significant differences were observed among final results with in different device groups.

Optimization of Sm3+ fluorescence in Sm-doped yttrium aluminum garnet: Application to pressure calibration in diamond-anvil cell at high temperature

NASA Astrophysics Data System (ADS)

Sanchez-Valle, Carmen; Daniel, Isabelle; Reynard, Bruno; Abraham, Robert; Goutaudier, Christelle

2002-10-01

Sm3+ concentration in Sm-doped yttrium aluminum garnet (Sm3+):YAG has been optimized for fluorescence yield and synthesis procedure for the production of strain-free small grain-size powder established. Concentration of 0.5 wt % Sm3+ displays an optimal fluorescence signal, three to five times stronger than the generally proposed concentration (4 wt %). The fluorescence of the samples has been studied as a function of temperature (300-873 K) and pressure (0-15 GPa). A comparison with standard pressure scales shows that the pressure evolution of Sm3+:YAG fluorescence is insensitive to the doping rate, and that temperature has only a limited effect on the pressure scale established at 300 K. The present results indicate that pressure can be determined from the Y1 line of 0.5 wt % Sm-doped YAG, with temperature correction for pi at room pressure and constant pressure shift, within the 300-873 K and 10-4-15 GPa pressure-temperature range, through the linear relation: P (GPa)=0.127 x([pi0-0.018 xDelta]T)-[pi] where pi0 corresponds to the Y1 frequency value at ambient conditions (16 185 cm-1).

Renal metabolic profiling of early renal injury and renoprotective effects of Poria cocos epidermis using UPLC Q-TOF/HSMS/MSE.

PubMed

Zhao, Ying-Yong; Lei, Ping; Chen, Dan-Qian; Feng, Ya-Long; Bai, Xu

2013-01-01

Poria cocos epidermis is one of ancient traditional Chinese medicines (TCMs), which is usually used for the treatment of chronic kidney disease (CKD) for thousands of years in China. A metabonomic approach based on ultra performance liquid chromatography coupled with quadrupole time-of-flight high-sensitivity mass spectrometry (UPLC Q-TOF/HSMS) and a mass spectrometry(Elevated Energy) (MS(E)) data collection technique was developed to obtained a systematic view of the development and progression of CKD and biochemistry mechanism of therapeutic effects of P. cocos epidermis (Fu-Ling-Pi, FLP). By partial least squares-discriminate analysis, 19 metabolites were identified as potential biomarkers of CKD. Among the 19 biomarkers, 10 biomarkers including eicosapentaenoic acid, docosahexaenoic acid, lysoPC(20:4), lysoPC(18:2), lysoPC(15:0), lysoPE(20:0/0:0), indoxyl sulfate, hippuric acid, p-cresol sulfate and allantoin were reversed to the control level in FLP-treated groups. The study indicates that FLP treatment can ameliorate CKD by intervening in some dominating metabolic pathways, such as fatty acid metabolism, phospholipid metabolism, purine metabolism and tryptophan metabolism. This work was for the first time to investigate the FLP therapeutic effect based on metabonomics technology, which is a potentially powerful tool to study the TCMs. Copyright © 2013 Elsevier B.V. All rights reserved.

Determinants of holmium:yttrium-aluminum-garnet laser time and energy during ureteroscopic laser lithotripsy.

PubMed

Molina, Wilson R; Marchini, Giovanni S; Pompeo, Alexandre; Sehrt, David; Kim, Fernando J; Monga, Manoj

2014-04-01

To evaluate the association of preoperative noncontrast computed tomography stone characteristics, laser settings, and stone composition with cumulative holmium:yttrium-aluminum-garnet (Ho:YAG) laser time/energy. We retrospectively reviewed patients who underwent semirigid/flexible ureteroscopy and Ho:YAG laser lithotripsy (200 or 365 μm laser fiber; 0.8-1.0 J energy; and 8-10 Hz rate) at 2 tertiary care centers (April 2010-May 2012). Studied parameters were as follows: patient's characteristics; stone characteristics (location, burden, hardness, and composition); total laser time and energy; and surgical outcomes. One hundred patients met our inclusion criteria. Mean stone size was 1.01 ± 0.42 cm and volume 0.33 ± 0.04 cm(3). Mean stone radiodensity was 990 ± 296 HU, and Hounsfield units density 13.8 ± 6.0 HU/mm. All patients were considered stone free. Stone size and volume had a significant positive correlation with laser energy (R = 0.516, P <.001; R = 0.621, P <.001) and laser time (R = 0.477, P <.001; R = 0.567, P <.001). When controlling for stone size, only the correlation between HU and laser time was significant (R = 0.262, P = .011). In the multivariate analysis, with exception of stone composition (P = .103), all parameters significantly increased laser energy (R(2) = 0.524). Multivariate analysis revealed a positive significant association of laser time with stone volume (P <.001) and Hounsfield units density (P <.001; R(2) = 0.512). In multivariate analysis for laser energy, only calcium phosphate stones required less energy to fragment compared with uric acid stones. No significant differences were found in the multivariate laser time model. Ho:YAG laser cumulative energy and total time are significantly affected by stone dimensions, hardness location, fiber size, and power. Kidney location, laser fiber size, and laser power have more influence on the final laser energy than on the total laser time. Calcium phosphate stones require less laser

Biodistribution of Yttrium-90-Labeled Anti-CD45 Antibody in a Nonhuman Primate Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemecek, Eneida; Hamlin, Donald K.; Fisher, Darrell R.

2005-01-15

Radioimmunotherapy may improve the outcome of hematopoietic cell transplantation for hematologic malignancies by delivering targeted radiation to hematopoietic organs while relatively sparing nontarget organs. We evaluated the organ localization of yttrium-90-labeled anti-CD45 (90Y-anti-CD45) antibody in macaques, a model that had previously predicted iodine-131-labeled anti-CD-45 (131I-anti-CD45) antibody biodistribution in humans. Experimental Design: Twelve Macaca nemestrina primates received anti-CD45 antibody labeled with 1 to 2 mCi of 90Y followed by serial blood sampling and marrow and lymph node biopsies, and necropsy. The content of 90Y per gram of tissue was determined by liquid scintillation spectrometry. Time-activity curves were constructed using average isotopemore » concentrations in each tissue at measured time points to yield the fractional residence time and estimate radiation absorbed doses for each organ per unit of administered activity. The biodistribution of 90Y-anti-CD45 antibody was then compared with that previously obtained with 131I-anti-CD45 antibody in macaques. Results: The spleen received 2,120, marrow 1,060, and lymph nodes 315 cGy/mCi of 90Y injected. The liver and lungs were the nontarget organs receiving the highest radiation absorbed doses (440 and 285 cGy/mCi, respectively). Ytrrium-90-labeled anti-CD45 antibody delivered 2.5- and 3.7-fold more radiation to marrow than to liver and lungs, respectively. The ratios previously observed with 131I-antiCD45 antibody were 2.5-and 2.2-fold more radiation to marrow than to liver and lungs, respectively. Conclusions: This study shows that 90Y-anti-CD45 antibody can deliver relatively selective radiation to hematopoietic tissues, with similar ratios of radiation delivered to target versus nontarget organs, as compared with the 131I immunoconjugate in the same animal model.« less

Immune activation underlies a sustained clinical response to Yttrium-90 radioembolisation in hepatocellular carcinoma.

PubMed

Chew, Valerie; Lee, Yun Hua; Pan, Lu; Nasir, Nurul J M; Lim, Chun Jye; Chua, Camillus; Lai, Liyun; Hazirah, Sharifah Nur; Lim, Tony Kiat Hon; Goh, Brian K P; Chung, Alexander; Lo, Richard H G; Ng, David; Filarca, Rene L F; Albani, Salvatore; Chow, Pierce K H

2018-02-13

Yttrium-90 (Y90)-radioembolisation (RE) significantly regresses locally advanced hepatocellular carcinoma and delays disease progression. The current study is designed to deeply interrogate the immunological impact of Y90-RE, which elicits a sustained therapeutic response. Time-of-flight mass cytometry and next-generation sequencing (NGS) were used to analyse the immune landscapes of tumour-infiltrating leucocytes (TILs), tumour tissues and peripheral blood mononuclear cells (PBMCs) at different time points before and after Y90-RE. TILs isolated after Y90-RE exhibited signs of local immune activation: higher expression of granzyme B (GB) and infiltration of CD8 + T cells, CD56 + NK cells and CD8 + CD56 + NKT cells. NGS confirmed the upregulation of genes involved in innate and adaptive immune activation in Y90-RE-treated tumours. Chemotactic pathways involving CCL5 and CXCL16 correlated with the recruitment of activated GB + CD8 + T cells to the Y90-RE-treated tumours. When comparing PBMCs before and after Y90-RE, we observed an increase in tumour necrosis factor-α on both the CD8 + and CD4 + T cells as well as an increase in percentage of antigen-presenting cells after Y90-RE, implying a systemic immune activation. Interestingly, a high percentage of PD-1 + /Tim-3 + CD8 + T cells coexpressing the homing receptors CCR5 and CXCR6 denoted Y90-RE responders. A prediction model was also built to identify sustained responders to Y90-RE based on the immune profiles from pretreatment PBMCs. High-dimensional analysis of tumour and systemic immune landscapes identified local and systemic immune activation that corresponded to the sustained response to Y90-RE. Potential biomarkers associated with a positive clinical response were identified and a prediction model was built to identify sustained responders prior to treatment. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is

Phosphatase-Resistant Analogues of Lysophosphatidic Acid

PubMed Central

Prestwich, Glenn D.; Gajewiak, Joanna; Zhang, Honglu; Xu, Xiaoyu; Yang, Guanghui; Serban, Monica

2008-01-01

Isoform-selective agonists and antagonists of the lysophosphatidic acid (LPA) G protein coupled receptors (GPCRs) have important potential applications in cell biology and therapy. LPA GPCRs regulate cancer cell proliferation, invasion, angiogenesis, and also biochemical resistance to chemotherapy- and radiotherapy-induced apoptosis. LPA and its analogues also are feedback inhibitors of the enzyme lysophospholipase D (lysoPLD, a.k.a., autotaxin, ATX), a central regulator of invasion and metastasis. For cancer therapy, the optimal therapeutic profile would be a metabolically stabilized, pan-LPA receptor antagonist that also inhibited lysoPLD. For protection of gastrointestinal mucosa and lymphocytes, LPA agonists would be desirable to minimize or reverse radiation or chemical-induced injury. Analogues of lysophosphatidic acid (LPA) that are chemically modified to be less susceptible to phospholipases and phosphatases show activity as long-lived receptor-specific agonists and antagonists for LPA receptors, as well as inhibitors for the lysoPLD activity of ATX. PMID:18454946

In situ probing of temperature in radio frequency thermal plasma using Yttrium ion emission lines during synthesis of yttria nanoparticles

NASA Astrophysics Data System (ADS)

Dhamale, G. D.; Tiwari, N.; Mathe, V. L.; Bhoraskar, S. V.; Ghorui, S.

2017-07-01

Particle feeding is used in the most important applications of radio frequency (r.f.) thermal plasmas like synthesis of nanoparticles and particle spheroidization. The study reports an in-situ investigation of radial distribution of temperature in such devices using yttrium ion emission lines under different rates of particle loading during synthesis of yttria nanoparticles. A number of interesting facts about the response of r.f. plasma to the rate of particle loading, hitherto unknown, are revealed. Observed phenomena are supported with experimental data from fast photographic experiments and actual synthesis results. The use of the Abel inversion technique together with simultaneous multi-track acquisition of emission spectra from different spatial locations using a CCD based spectrometer allowed us to extract accurate distribution of temperature inside the plasma in the presence of inherent instabilities. The temperature profiles of this type of plasma have been measured possibly for the first time while particles are being fed into the plasma. Observed changes in the temperature profiles as the particle feed rate increases are very significant. Reaction forces resulting from particle evaporation, and increased skin depth owing to the decrease in electrical conductivity in the edge region are proposed as the two different mechanisms to account for the observed changes in the temperature profile as the powder feed rate is increased. Quantitative analyses supporting the proposed mechanisms are presented.

Model-Based Radiation Dose Correction for Yttrium-90 Microsphere Treatment of Liver Tumors With Central Necrosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ching-Sheng; Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Lin, Ko-Han

Purpose: The objectives of this study were to model and calculate the absorbed fraction {phi} of energy emitted from yttrium-90 ({sup 90}Y) microsphere treatment of necrotic liver tumors. Methods and Materials: The tumor necrosis model was proposed for the calculation of {phi} over the spherical shell region. Two approaches, the semianalytic method and the probabilistic method, were adopted. In the former method, the range--energy relationship and the sampling of electron paths were applied to calculate the energy deposition within the target region, using the straight-ahead and continuous-slowing-down approximation (CSDA) method. In the latter method, the Monte Carlo PENELOPE code wasmore » used to verify results from the first method. Results: The fraction of energy, {phi}, absorbed from {sup 90}Y by 1-cm thickness of tumor shell from microsphere distribution by CSDA with complete beta spectrum was 0.832 {+-} 0.001 and 0.833 {+-} 0.001 for smaller (r{sub T} = 5 cm) and larger (r{sub T} = 10 cm) tumors (where r is the radii of the tumor [T] and necrosis [N]). The fraction absorbed depended mainly on the thickness of the tumor necrosis configuration, rather than on tumor necrosis size. The maximal absorbed fraction {phi} that occurred in tumors without central necrosis for each size of tumor was different: 0.950 {+-} 0.000, and 0.975 {+-} 0.000 for smaller (r{sub T} = 5 cm) and larger (r{sub T} = 10 cm) tumors, respectively (p < 0.0001). Conclusions: The tumor necrosis model was developed for dose calculation of {sup 90}Y microsphere treatment of hepatic tumors with central necrosis. With this model, important information is provided regarding the absorbed fraction applicable to clinical {sup 90}Y microsphere treatment.« less

Manufacturing Technology of Ceramic Pebbles for Breeding Blanket

PubMed Central

Stefanelli, Eleonora; Del Serra, Daniele; Malquori, Stefano

2018-01-01

An open issue for the fusion power reactor is the choice of breeding blanket material. The possible use of Helium-Cooled Pebble Breeder ceramic material in the form of pebble beds is of great interest worldwide as demonstrated by the numerous studies and research on this subject. Lithium orthosilicate (Li4SiO4) is a promising breeding material investigated in this present study because the neutron capture of Li-6 allows the production of tritium, 6Li (n, t) 4He. Furthermore, lithium orthosilicate has the advantages of low activation characteristics, low thermal expansion coefficient, high thermal conductivity, high density and stability. Even if they are far from the industrial standard, a variety of industrial processes have been proposed for making orthosilicate pebbles with diameters of 0.1–1 mm. However, some manufacturing problems have been observed, such as in the chemical stability (agglomeration phenomena). The aim of this study is to provide a new methodology for the production of pebbles based on the drip casting method, which was jointly developed by the DICI-University of Pisa and Industrie Bitossi. Using this new (and alternative) manufacturing technology, in the field of fusion reactors, appropriately sized ceramic pebbles could be produced for use as tritium breeders. PMID:29724071

Manufacturing Technology of Ceramic Pebbles for Breeding Blanket.

PubMed

Lo Frano, Rosa; Puccini, Monica; Stefanelli, Eleonora; Del Serra, Daniele; Malquori, Stefano

2018-05-02

An open issue for the fusion power reactor is the choice of breeding blanket material. The possible use of Helium-Cooled Pebble Breeder ceramic material in the form of pebble beds is of great interest worldwide as demonstrated by the numerous studies and research on this subject. Lithium orthosilicate (Li₄SiO₄) is a promising breeding material investigated in this present study because the neutron capture of Li-6 allows the production of tritium, 6Li (n, t) 4He. Furthermore, lithium orthosilicate has the advantages of low activation characteristics, low thermal expansion coefficient, high thermal conductivity, high density and stability. Even if they are far from the industrial standard, a variety of industrial processes have been proposed for making orthosilicate pebbles with diameters of 0.1⁻1 mm. However, some manufacturing problems have been observed, such as in the chemical stability (agglomeration phenomena). The aim of this study is to provide a new methodology for the production of pebbles based on the drip casting method, which was jointly developed by the DICI-University of Pisa and Industrie Bitossi. Using this new (and alternative) manufacturing technology, in the field of fusion reactors, appropriately sized ceramic pebbles could be produced for use as tritium breeders.

Application of reflectance confocal microscopy to evaluate skin damage after irradiation with an yttrium-scandium-gallium-garnet (YSGG) laser.

PubMed

Yue, Xueping; Wang, Hongwei; Li, Qing; Li, Linfeng

2017-02-01

The objective of this study was to observe the characteristics of the skin after irradiation with a 2790-nm yttrium-scandium-gallium-garnet (YSGG) laser using reflectance confocal microscopy (RCM). A 2790-nm YSGG laser was used to irradiate fresh foreskin (four doses, at spot density 3) in vitro. The characteristics of microscopic ablative columns (MAC), thermal coagulation zone (TCZ), and microscopic treatment zones (MTZ) were observed immediately after irradiation using digital microscope and RCM. The characteristics of MAC, TCZ, and MTZ with variations in pulse energy were comparatively analyzed. After irradiation, MAC, TCZ, and MTZ characteristics and undamaged skin between MTZs can be observed by RCM. The depth and width of MTZ obviously increased with the increase in pulse energy. At 80, 120, and 160 mJ/microbeam (MB), the MTZ actual area and proportion were about two times that of the theoretical value and three times at 200 mJ/MB. With increases in depth, the single MAC gradually decreased in a fingertip-shaped model, with TCZ slowly increasing, and MTZ slightly decreasing in a columnar shape. RCM was able to determine the characteristics of thermal injury on the skin after the 2790-nm YSGG laser irradiation with different pulse energies. Pulse energy higher than 200 mJ/MB may have much larger thermal injury and side effect. RCM could be used in the clinic in future.

Use of Chelex-100 for selectively removing Y-90 from its parent Sr-90

DOEpatents

Huntley, Mark W.

1996-01-01

A method for selectively removing yttrium-90 from its parent strontium-90 contained in an environmental sample includes loading the sample onto a column containing a chelating ion-exchange resin capable of retaining yttrium-90; washing the column with a solution capable of removing strontium, calcium, and other contaminants from the yttrium-90 fraction retained on the column; removing excess acetate salts from the column; eluting yttrium-90 solution from the column and adjusting the pH of this solution to about 2.7; filtering the yttrium-90 solution and weighing this solution for gravimetric yield; and, counting the yttrium-90 containing solution with a radiological counter for a time sufficient to achieve the statistical accuracy desired. It is preferred that the chelating ion-exchange resin is a bidente ligand having the chemical name iminodiacetic acid mounted on a divinyl benzene substrate, converted from sodium form to ammonia form.

Use of Chelex-100 for selectively removing Y-90 from its parent Sr-90

DOEpatents

Huntley, M.W.

1996-02-27

A method for selectively removing yttrium-90 from its parent strontium-90 contained in an environmental sample includes loading the sample onto a column containing a chelating ion-exchange resin capable of retaining yttrium-90; washing the column with a solution capable of removing strontium, calcium, and other contaminants from the yttrium-90 fraction retained on the column; removing excess acetate salts from the column; eluting yttrium-90 solution from the column and adjusting the pH of this solution to about 2.7; filtering the yttrium-90 solution and weighing this solution for gravimetric yield; and, counting the yttrium-90 containing solution with a radiological counter for a time sufficient to achieve the statistical accuracy desired. It is preferred that the chelating ion-exchange resin is a ligand having the chemical name iminodiacetic acid mounted on a divinyl benzene substrate, converted from sodium form to ammonia form.

Three-year clinical follow-up after strontium-90/yttrium-90 beta-irradiation for the treatment of in-stent coronary restenosis.

PubMed

Baierl, Verena; Baumgartner, Simone; Pöllinger, Barbara; Leibig, Marcus; Rieber, Johannes; König, Andreas; Krötz, Florian; Sohn, Hae-Young; Siebert, Uwe; Haimerl, Wolfgang; Dühmke, Eckhart; Theisen, Karl; Klauss, Volker; Schiele, Thomas M

2005-11-15

Because late vessel failure has been speculated as a possible limitation of vascular brachytherapy, we conducted a prospective clinical evaluation at 6, 12, 24, and 36 months of follow-up after irradiation with strontium-90/yttrium-90 for in-stent restenosis, regardless of the patient's symptomatic status. We report complete 3-year follow-up data for 106 consecutive patients. The cumulative rate of death at 6, 12, 24, and 36 months was 0.9%, 0.9%, 0.9%, and 1.9% respectively. The corresponding rates for acute ST-elevation myocardial infarction were 2.8%, 4.7%, 4.7%, and 4.7%, respectively. The cumulative rate of late thrombotic occlusion at 6, 12, 24, and 36 months was 3.8%, 4.7%, 4.7%, and 4.7%, respectively. The corresponding rates of target lesion revascularization and target vessel revascularization were 8.5% and 12.3% (p = 0.046), 14.2% (p = 0.157) and 18.0% (p = 0.046), 12.3% and 18.9% (p = 0.008), and 21.7% (p = 0.083) and 29.2% (p = 0.005), respectively. The cumulative rate of all major adverse cardiovascular events at 6, 12, 24, and 36 months was 16.1%, 24.5% (p = 0.003), 27.4% (p = 0.083), and 35.8% (p = 0.003), respectively. In conclusion, these results indicate a delayed and, even in the third year after the index procedure, continued restenotic process after beta irradiation of in-stent restenotic lesions.

Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Suresh de, E-mail: suresh.desilva@unsw.edu.au; Mackie, Simon; Aslan, Peter

BackgroundIntra-arterial brachytherapy with yttrium-90 ({sup 90}Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of {sup 90}Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with {sup 90}Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extentmore » of tissue necrosis from {sup 90}Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with {sup 90}Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the {sup 90}Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10{sup 6}) of bland microspheres.ConclusionThis study showed that radioembolization with {sup 90}Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of {sup 90}Y resin microspheres for the localized treatment of kidney tumors.« less

Evaluation of critical distances for energy transfer between Pr3+ and Ce3+ in yttrium aluminium garnet

NASA Astrophysics Data System (ADS)

Zeng, Peng; Wei, Xiantao; Zhou, Shaoshuai; Yin, Min; Chen, Yonghu

2016-09-01

A series of Pr3+/Ce3+ doped yttrium aluminium garnet (Y3Al5O12 or simply YAG) phosphors were synthesized to investigate the energy transfer between Pr3+ and Ce3+ for their potential application in a white light-emitting diode and quantum information storage and processing. The excitation and emission spectra of YAG:Pr3+/Ce3+ were measured and analyzed, and it revealed that the reabsorption between Pr3+ and Ce3+ was so weak that it can be ignored, and the energy transfer from Pr3+ (5d) to Ce3+ (5d) and Ce3+ (5d) to Pr3+ (1D2) did occur. By analyzing the excitation and the emission spectra, the energy transfer from Pr3+ (5d) to Ce3+ (5d) and Ce3+ (5d) to Pr3+ (1D2) was examined in detail with an original strategy deduced from fluorescence dynamics and the Dexter energy transfer theory, and the critical distances of energy transfer were derived to be 7.9 Å and 4.0 Å for Pr3+ (5d) to Ce3+ (5d) and Ce3+ (5d) to Pr3+ (1D2), respectively. The energy transfer rates of the two processes of various concentrations were discussed and evaluated. Furthermore, for the purpose of sensing a single Pr3+ state with a Ce3+ ion, the optimal distance of Ce3+ from Pr3+ was evaluated as 5.60 Å, where the probability of success reaches its maximum value of 78.66%, and meanwhile the probabilities were evaluated for a series of Y3+ sites in a YAG lattice. These results will be of valuable reference for achievement of the optimal energy transfer efficiency in Pr3+/Ce3+ doped YAG and other similar systems.

PKU-PET-II: A novel SiPM-based PET imaging system for small animals

NASA Astrophysics Data System (ADS)

Xie, Zhaoheng; Li, Suying; Zhou, Kun; Vuletic, Ivan; Meng, Xiangxi; Zhu, Sihao; Xu, Huan; Yang, Kun; Xu, Baixuan; Zhang, Jinming; Ren, Qiushi

2018-01-01

The objective of this study was to introduce, describe, and validate the performance of a novel preclinical silicon photomultiplier (SiPM)-based PET system (PKU-PET-II). Briefly, the detector assembly consisted of cerium-doped lutetium-yttrium oxyorthosilicate (LYSO) crystals, with dimensions of 2 ×2 ×15 mm3, that offered a 60 mm transaxial field of view (FOV) and 32 mm axial FOV, respectively. The compact front-end electronics readout and digital controller implemented architecture in the FPGA were noteworthy improvements in PKU-PET-II over its predecessor (PKU-PET-I). Based on the National Electrical Manufacturers Association (NEMA) NU 04-2008 standards, the design of the PKU-PET-II system was validated by a phantom experiment. The results presented spatial resolution (evaluated as full width at half maximum) with a system range from 1.68 ±0.07 to 2.31 ±0.03 mm at the FOV center and from 1.43 ±0.02 to 2.10 ±0.10 mm at the 1/4th axial FOV, respectively. The system's absolute sensitivity at the center position was 1.35% with the coincidence window of 6 ns and energy window of 300-700 keV. In addition, the NEMA image quality phantom and an animal study results validated the system imaging performance in preclinical imaging application. In conclusion, this SiPM-based, small-animal PET system (PKU-PET-II) provided higher-resolution, adequate sensitivity, and excellent image quality and has potential as a useful tool for real-time imaging of disease progression and development in vivo.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leggett, Rich

The transition metal yttrium (Y, atomic number 39) is chemically similar to elements in the lanthanide family (atomic numbers 57-71, lanthanum through lutetium) and is always present with the lanthanides in rare earth ores. Yttrium and the lanthanide holmium are particularly close chemical and physical analogues and are referred to as geochemical twins because they typically show little fractionation in geological material. Extensive measurements on rocks, soils, and meteorites indicate that the Y/Ho mass concentration ratio rarely falls far from the “chondritic” or “solar system” ratio of ~26. Our paper presents a new biokinetic model for yttrium in adult humansmore » and examines whether yttrium and holmium may be biological as well as geochemical twins. Collected data on yttrium and holmium in plants and human tissues do not allow precise derivations of Y/Ho concentration ratios but with occasional exceptions yield ratios that are reasonably consistent with chondritic values. Predictions of the time-dependent behavior of yttrium in adult humans based on the yttrium model presented here closely approximate predictions of the behavior of holmium based on a previously developed model for holmium. We know that yttrium and holmium are close biological analogues, but the available comparative data are too limited and imprecise to reveal whether there are any significant differences in their biological behavior.« less

Lysophosphatidylcholine Regulates Sexual Stage Differentiation in the Human Malaria Parasite Plasmodium falciparum.

PubMed

Brancucci, Nicolas M B; Gerdt, Joseph P; Wang, ChengQi; De Niz, Mariana; Philip, Nisha; Adapa, Swamy R; Zhang, Min; Hitz, Eva; Niederwieser, Igor; Boltryk, Sylwia D; Laffitte, Marie-Claude; Clark, Martha A; Grüring, Christof; Ravel, Deepali; Blancke Soares, Alexandra; Demas, Allison; Bopp, Selina; Rubio-Ruiz, Belén; Conejo-Garcia, Ana; Wirth, Dyann F; Gendaszewska-Darmach, Edyta; Duraisingh, Manoj T; Adams, John H; Voss, Till S; Waters, Andrew P; Jiang, Rays H Y; Clardy, Jon; Marti, Matthias

2017-12-14

Transmission represents a population bottleneck in the Plasmodium life cycle and a key intervention target of ongoing efforts to eradicate malaria. Sexual differentiation is essential for this process, as only sexual parasites, called gametocytes, are infective to the mosquito vector. Gametocyte production rates vary depending on environmental conditions, but external stimuli remain obscure. Here, we show that the host-derived lipid lysophosphatidylcholine (LysoPC) controls P. falciparum cell fate by repressing parasite sexual differentiation. We demonstrate that exogenous LysoPC drives biosynthesis of the essential membrane component phosphatidylcholine. LysoPC restriction induces a compensatory response, linking parasite metabolism to the activation of sexual-stage-specific transcription and gametocyte formation. Our results reveal that malaria parasites can sense and process host-derived physiological signals to regulate differentiation. These data close a critical knowledge gap in parasite biology and introduce a major component of the sexual differentiation pathway in Plasmodium that may provide new approaches for blocking malaria transmission. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

A composite material based on nanoparticles of yttrium (III) oxide for the selective and sensitive electrochemical determination of acetaminophen.

PubMed

Baytak, Aysegul Kutluay; Teker, Tugce; Duzmen, Sehriban; Aslanoglu, Mehmet

2016-09-01

An electrochemical sensor was prepared by modifying a glassy carbon electrode (GCE) with a composite of yttrium (III) oxide nanoparticles (Y2O3NPs) and carbon nanotubes (CNTs) for the determination of acetaminophen (ACT). Compared with a bare GCE and CNTs/GCE, the Y2O3NPs/CNTs/GCE exhibited a well-defined redox couple for ACT and highly enhanced the current response. The separations in the anodic and cathodic peak potentials (ΔEp) for ACT were 552mV, 24mV and 10mV at ba4re GCE, CNTs/GCE and Y2O3NPs/CNTs/GCE, respectively. The observation of only 10mV of ΔEp for ACT at Y2O3NPs/CNTs/GCE was a clear indication of a great acceleration of the electrode process compared to bare GCE and GCE modified with CNTs. Also, l-ascorbic acid (l-AA) and l-tyrosine (l-TRY) did not interfere with the selective determination of ACT. Square wave voltammetry (SWV) was performed for the quantification of ACT. A linear plot was obtained for current responses versus the concentrations of ACT over the range from 1.0×10(-10) to 1.8×10(-8)M with a detection limit of 3.0×10(-11)M (based on 3Sb/m). The proposed composite material provided high electrocatalytic activity, improved voltammetric behavior, good selectivity and good reproducibility. The accurate quantification of ACT makes the proposed electrode of great interest for the public health. Copyright © 2016 Elsevier B.V. All rights reserved.

Embolisation of the Gastroduodenal Artery is Not Necessary in the Presence of Reversed Flow Before Yttrium-90 Radioembolisation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daghir, Ahmed A., E-mail: ahmeddaghir@doctors.net.uk; Gungor, Hatice; Haydar, Ali A.

2012-08-15

Introduction: The gastroduodenal artery (GDA) is usually embolised to avoid nontarget dispersal before yttrium-90 (Y{sup 90}) radioembolisation to treat liver metastases. In a minority of patients, there is retrograde flow in the GDA. The purpose of this study was to determine if there is any increased risk from maintaining a patent GDA in patients with reversed flow. Materials and Methods: A retrospective review was performed of all patients undergoing Y{sup 90} radioembolisation at our institution. The incidence of toxicities arising from nontarget radioembolisation by way of the GDA (gastric/duodenal ulceration, gastric/duodenal bleeding, and pancreatitis) and death occurring within 2 monthsmore » of treatment were compared between the reversed and the antegrade GDA groups. Results: Ninety-two patients underwent preliminary angiography. Reversed GDA flow was found on angiography in 14.1% of cases; the GDA was not embolised in these patients. The GDA was coiled in 55.7% of patients with antegrade GDA flow to prevent inadvertent dispersal of radioembolic material. There was no increased toxicity related to nontarget dispersal by way of the GDA, or increased early mortality, in patients with reversed GDA flow (P > 0.05). Conclusion: In patients with reversed GDA flow, maintenance of a patent GDA before administration of Y{sup 90} radioembolisation does not increase the risk of toxicity from nontarget dispersal. Therapeutic injection, with careful monitoring to identify early vascular stasis, may be safely performed beyond the origin of the patent GDA. A patent GDA with reversed flow provides forward drive for infused particles and may allow alternative access to the hepatic circulation.« less

Performance evaluation of neuro-PET using silicon photomultipliers

NASA Astrophysics Data System (ADS)

Jung, Jiwoong; Choi, Yong; Jung, Jin Ho; Kim, Sangsu; Im, Ki Chun

2016-05-01

Recently, we have developed the second prototype Silicon photomultiplier (SiPM) based positron emission tomography (PET) scanner for human brain imaging. The PET system was comprised of detector block which consisted of 4×4 SiPMs and 4×4 Lutetium Yttrium Orthosilicate arrays, charge signal transmission method, high density position decoder circuit and FPGA-embedded ADC boards. The purpose of this study was to evaluate the performance of the newly developed neuro-PET system. The energy resolution, timing resolution, spatial resolution, sensitivity, stability of the photo-peak position and count rate performance were measured. Tomographic image of 3D Hoffman brain phantom was also acquired to evaluate imaging capability of the neuro-PET. The average energy and timing resolutions measured for 511 keV gamma rays were 17±0.1% and 3±0.3 ns, respectively. Spatial resolution and sensitivity at the center of field of view (FOV) were 3.1 mm and 0.8%, respectively. The average scatter fraction was 0.4 with an energy window of 350-650 keV. The maximum true count rate and maximum NECR were measured as 43.3 kcps and 6.5 kcps at an activity concentration of 16.7 kBq/ml and 5.5 kBq/ml, respectively. Long-term stability results show that there was no significant change in the photo-peak position, energy resolution and count rate for 60 days. Phantom imaging studies were performed and they demonstrated the feasibility for high quality brain imaging. The performance tests and imaging results indicate that the newly developed PET is useful for brain imaging studies, if the axial FOV is extended to improve the system sensitivity.

Progress Towards Left-Handed Electromagnetic Waves in Rare-Earth Doped Crystals

NASA Astrophysics Data System (ADS)

Brewer, Nicholas Riley

In 1968 Victor Veselago determined that a material with both a negative permittivity and negative permeability would have some extraordinary properties. The index of refraction of this material would be negative and light propagating inside would be 'left-handed'. This research went relatively unnoticed until the year 2000 when John Pendry discovered that a lens with an index of refraction of n = -1 could, in principle, have infinite resolution. Since 2000, research into negative index materials has exploded. The challenging part of this research is to get a material to respond to magnetic fields at optical frequencies. Artificially created metamaterials are able to achieve this and have been the focus of most negative index research. The long term goal of our project is to produce left-handed light in an atomic system. In order to do this, an atomic transition needs to be utilized that is magnetic dipole in character. Pure magnetic dipole transitions in the optical regime are more rare and fundamentally much weaker than the electric dipole transitions typically used in atomic physics experiments. They can be found, however, in the complex atomic structure of rare-earth elements. The 7F0 → 5D 1 transition in europium doped yttrium orthosilicate (Eu3+:Y 2SiO5) has a wavelength of 527.5 nm and is a pure magnetic dipole transition. We measured its dipole moment to be (0.063 +/- 0.005)mu B via Rabi oscillations, inferring a magnetization on the order of 10 -2 A/m. Demonstrating this large magnetic response at an optical frequency is a major first step in realizing left-handed light in atomic systems.

Biomarkers of Morbid Obesity and Prediabetes by Metabolomic Profiling of Human Discordant Phenotypes.

PubMed

Tulipani, Sara; Palau-Rodriguez, Magali; Miñarro Alonso, Antonio; Cardona, Fernando; Marco-Ramell, Anna; Zonja, Bozo; Lopez de Alda, Miren; Muñoz-Garach, Araceli; Sanchez-Pla, Alejandro; Tinahones, Francisco J; Andres-Lacueva, Cristina

2016-12-01

Metabolomic studies aimed to dissect the connection between the development of type 2 diabetes and obesity are still scarce. In the present study, fasting serum from sixty-four adult individuals classified into four sex-matched groups by their BMI [non-obese versus morbid obese] and the increased risk of developing diabetes [prediabetic insulin resistant state versus non-prediabetic non-insulin resistant] was analyzed by LC- and FIA-ESI-MS/MS-driven metabolomic approaches. Altered levels of [lyso]glycerophospholipids was the most specific metabolic trait associated to morbid obesity, particularly lysophosphatidylcholines acylated with margaric, oleic and linoleic acids [lysoPC C17:0: R=-0.56, p=0.0003; lysoPC C18:1: R=-0.61, p=0.0001; lysoPC C18:2 R=-0.64, p<0.0001]. Several amino acids were biomarkers of risk of diabetes onset associated to obesity. For instance, glutamate significantly associated with fasting insulin [R=0.5, p=0.0019] and HOMA-IR [R=0.46, p=0.0072], while glycine showed negative associations [fasting insulin: R=-0.51, p=0.0017; HOMA-IR: R=-0.49, p=0.0033], and the branched chain amino acid valine associated to prediabetes and insulin resistance in a BMI-independent manner [fasting insulin: R=0.37, p=0.0479; HOMA-IR: R=0.37, p=0.0468]. Minority sphingolipids including specific [dihydro]ceramides and sphingomyelins also associated with the prediabetic insulin resistant state, hence deserving attention as potential targets for early diagnosis or therapeutic intervention. Copyright © 2016 Elsevier B.V. All rights reserved.

Alteration in metabolic signature and lipid metabolism in patients with angina pectoris and myocardial infarction.

PubMed

Park, Ju Yeon; Lee, Sang-Hak; Shin, Min-Jeong; Hwang, Geum-Sook

2015-01-01

Lipid metabolites are indispensable regulators of physiological and pathological processes, including atherosclerosis and coronary artery disease (CAD). However, the complex changes in lipid metabolites and metabolism that occur in patients with these conditions are incompletely understood. We performed lipid profiling to identify alterations in lipid metabolism in patients with angina and myocardial infarction (MI). Global lipid profiling was applied to serum samples from patients with CAD (angina and MI) and age-, sex-, and body mass index-matched healthy subjects using ultra-performance liquid chromatography/quadruple time-of-flight mass spectrometry and multivariate statistical analysis. A multivariate analysis showed a clear separation between the patients with CAD and normal controls. Lysophosphatidylcholine (lysoPC) and lysophosphatidylethanolamine (lysoPE) species containing unsaturated fatty acids and free fatty acids were associated with an increased risk of CAD, whereas species of lysoPC and lyso-alkyl PC containing saturated fatty acids were associated with a decreased risk. Additionally, PC species containing palmitic acid, diacylglycerol, sphingomyelin, and ceramide were associated with an increased risk of MI, whereas PE-plasmalogen and phosphatidylinositol species were associated with a decreased risk. In MI patients, we found strong positive correlation between lipid metabolites related to the sphingolipid pathway, sphingomyelin, and ceramide and acute inflammatory markers (high-sensitivity C-reactive protein). The results of this study demonstrate altered signatures in lipid metabolism in patients with angina or MI. Lipidomic profiling could provide the information to identity the specific lipid metabolites under the presence of disturbed metabolic pathways in patients with CAD.

Novel enzymatic method for assaying Lp-PLA2 in serum.

PubMed

Yamaura, Saki; Sakasegawa, Shin-Ichi; Koguma, Emisa; Ueda, Shigeru; Kayamori, Yuzo; Sugimori, Daisuke; Karasawa, Ken

2018-06-01

Measurement of lipoprotein-associated phospholipase A 2 (Lp-PLA 2 ) can be used as an adjunct to traditional cardiovascular risk factors for identifying individuals at higher risk of cardiovascular events. This can be performed by quantification of the protein concentration using an ELISA platform or by measuring Lp-PLA 2 activity using platelet-activating factor (PAF) analog as substrate. Here, an enzymatic Lp-PLA 2 activity assay method using 1-O-Hexadecyl-2-acetyl-rac-glycero-3-phosphocholine (rac C 16 PAF) was developed. The newly revealed substrate specificity of lysoplasmalogen-specific phospholipase D (lysophospholipase D (LysoPLD)) was exploited. Lp-PLA 2 hydrolyzes 1-O-Hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (C 16 PAF) to 1-O-Hexadecyl-2-hydroxy-sn-glycero-3-phosphocholine (LysoPAF). LysoPLD acted on LysoPAF, and the hydrolytically released choline was detected by choline oxidase. Regression analysis of Lp-PLA 2 activity measured by the enzymatic Lp-PLA 2 activity assay vs. two chemical Lp-PLA 2 activity assays, i.e. LpPLA 2 FS and PLAC® test, and ELISA, gave the following correlation coefficients: 0.990, 0.893 and 0.785, respectively (n = 30). Advantages of this enzymatic Lp-PLA 2 activity assay compared with chemical Lp-PLA 2 methods include the following; (i) only requires two reagents enabling a simple two-point linear calibration method with one calibrator (ii) no need for inhibitors of esterase-like activity in serum. Copyright © 2018 Elsevier B.V. All rights reserved.

Nanometer-Thick Yttrium Iron Garnet Film Development and Spintronics-Related Study

NASA Astrophysics Data System (ADS)

Chang, Houchen

In the last decade, there has been a considerable interest in using yttrium iron garnet (Y3Fe5O12, YIG) materials for magnetic insulator-based spintronics studies. This interest derives from the fact that YIG materials have very low intrinsic damping. The development of YIG-based spintronics demands YIG films that have a thickness in the nanometer (nm) range and at the same time exhibit low damping similar to single-crystal YIG bulk materials. This dissertation reports comprehensive experimental studies on nm-thick YIG films by magnetron sputtering techniques. Optimization of sputtering control parameters and post-deposition annealing processes are discussed in detail. The feasibility of low-damping YIG nm-thick film growth via sputtering is demonstrated. A 22.3-nm-thick YIG film, for example, shows a Gilbert damping constant of less than 1.0 x 10-4. The demonstration is of great technological significance because sputtering is a thin film growth technique most widely used in industry. The spin Seebeck effect (SSE) refers to the generation of spin voltage in a ferromagnet (FM) due to a temperature gradient. The spin voltage can produce a pure spin current into a normal metal (NM) that is in contact with the FM. Various theoretical models have been proposed to interpret the SSE, although a complete understanding of the effect has not been realized yet. In this dissertation the study of the role of damping on the SSE in YIG thin films is conducted for the first time. With the thin film development method mentioned in the last paragraph, a series of YIG thin films showing very similar structural and static magnetic properties but rather different Gilbert damping values were prepared. A Pt capping layer was grown on each YIG film to probe the strength of the SSE. The experimental data show that the YIG films with a smaller intrinsic Gilbert damping shows a stronger SSE. The majority of the previous studies on YIG spintronics utilized YIG films that were grown on single

A low-fluence 1064-nm Q-switched neodymium-doped yttrium aluminium garnet laser for the treatment of café-au-lait macules.

PubMed

Kim, Hyeong-Rae; Ha, Jeong-Min; Park, Min-Soo; Lee, Young; Seo, Young-Joon; Kim, Chang-Deok; Lee, Jeung-Hoon; Im, Myung

2015-09-01

Café-au-lait macules (CALMs) are a common pigmentary disorder. Although a variety of laser modalities have been used to treat CALMs, their efficacies vary and dyspigmentation may develop. We evaluated the clinical efficacy and safety of a low-fluence 1064-nm Q-switched neodymium-doped yttrium aluminium garnet (Nd:YAG) laser for the treatment of CALMs. In a preliminary investigation, 6 patients underwent a split-lesion comparative study with 532- and 1064-nm Q-switched Nd:YAG laser treatment. In total, 32 patients with 39 CALMs were enrolled in a subsequent prospective trial to evaluate the treatment with a low-fluence 1064-nm Q-switched Nd:YAG laser. In the preliminary study, the 1064-nm treatment group had a more favorable response and a shorter recovery time. In a subsequent prospective trial of a 1064-nm laser, 74.4% of the lesions showed a clinical response with clearance of ≥50.0%. The treatment regimen was well tolerated; 15.4% of patients experienced adverse events. The study participants were followed for 6 months, and there were no relevant treatment controls in the prospective trial group. Low-fluence 1064-nm Q-switched Nd:YAG laser therapy afforded good clinical improvement for treating CALMs. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

Erbium:Yttrium Aluminum Garnet Laser-Activated Sodium Hypochlorite Irrigation: A Promising Procedure for Minimally Invasive Endodontics.

PubMed

Cheng, Xiaogang; Tian, Tiantian; Tian, Yu; Xiang, Doudou; Qiu, Jun; Liu, Xiaohua; Yu, Qing

2017-12-01

This study was to evaluate the potential of Erbium:Yttrium Aluminum Garnet laser-activated sodium hypochlorite irrigation (Er:YAG + NaOCl) for minimally invasive endodontics (MIE). Er:YAG laser irradiation can dramatically enhance the penetration of NaOCl, which may be a promising protocol for MIE. Extracted human teeth were contaminated with Enterococcus faecalis for 4 weeks. The infected canals were then shaped to different apical terminal working widths (ATWW, 15#/0.04, 20#/0.04, 25#/0.04, 30#/0.04, and 40#/0.04) and treated with either Er:YAG + NaOCl (0.3 W, 20 sec) or NaOCl alone. Then, the ATWW were fixed at 15#/0.04, and the canals were treated with Er:YAG + NaOCl at 0.3 W for 40 and 60 sec, or at 0.5 and 1.0 W for 20 sec. Finally, bacterial reductions were evaluated using the cell count method. Er:YAG + NaOCl showed a higher disinfection efficacy at each ATWW compared with NaOCl alone (p < 0.001). The maximum bacterial reduction was 99.9% for the 40#/Er:YAG + NaOCl group and 93.6% for the 40#/NaOCl group. To achieve similar disinfection efficacy, the Er:YAG + NaOCl group needed a smaller ATWW than the NaOCl group. At a fixed ATWW, increasing the output power of the Er:YAG laser was more effective than increasing the radiation time to improve the disinfection efficacy of Er:YAG + NaOCl. The 15#/Er:YAG + NaOCl group reached the maximum bacterial reduction of 99.2% when the Er:YAG laser was activated at 1.0 W for 20 sec. The 15#/Er:YAG + NaOCl with the Er:YAG laser irradiation at 1.0 W for 20 sec may be considered a promising procedure for MIE.

Comparison of TOF-PET and Bremsstrahlung SPECT Images of Yttrium-90: A Monte Carlo Simulation Study.

PubMed

Takahashi, Akihiko; Himuro, Kazuhiko; Baba, Shingo; Yamashita, Yasuo; Sasaki, Masayuki

2018-01-01

Yttrium-90 ( 90 Y) is a beta particle nuclide used in targeted radionuclide therapy which is available to both single-photon emission computed tomography (SPECT) and time-of-flight (TOF) positron emission tomography (PET) imaging. The purpose of this study was to assess the image quality of PET and Bremsstrahlung SPECT by simulating PET and SPECT images of 90 Y using Monte Carlo simulation codes under the same conditions and to compare them. In-house Monte Carlo codes, MCEP-PET and MCEP-SPECT, were employed to simulate images. The phantom was a torso-shaped phantom containing six hot spheres of various sizes. The background concentrations of 90 Y were set to 50, 100, 150, and 200 kBq/mL, and the concentrations of the hot spheres were 10, 20, and 40 times of those of the background concentrations. The acquisition time was set to 30 min, and the simulated sinogram data were reconstructed using the ordered subset expectation maximization method. The contrast recovery coefficient (CRC) and contrast-to-noise ratio (CNR) were employed to evaluate the image qualities. The CRC values of SPECT images were less than 40%, while those of PET images were more than 40% when the hot sphere was larger than 20 mm in diameter. The CNR values of PET images of hot spheres of diameter smaller than 20 mm were larger than those of SPECT images. The CNR values mostly exceeded 4, which is a criterion to evaluate the discernibility of hot areas. In the case of SPECT, hot spheres of diameter smaller than 20 mm were not discernable. On the contrary, the CNR values of PET images decreased to the level of SPECT, in the case of low concentration. In almost all the cases examined in this investigation, the quantitative indexes of TOF-PET 90 Y images were better than those of Bremsstrahlung SPECT images. However, the superiority of PET image became critical in the case of low activity concentrations.

Pulmonary Laser Metastasectomy by 1318-nm Neodymium-Doped Yttrium-Aluminum Garnet Laser: A Retrospective Study About Laser Metastasectomy of the Lung.

PubMed

Porrello, Calogero; Gullo, Roberto; Vaglica, Antonino; Scerrino, Gregorio; Salamone, Giuseppe; Licari, Leo; Raspanti, Cristina; Gulotta, Eliana; Gulotta, Gaspare; Cocorullo, Gianfranco

2018-04-01

The lungs are among the first organ affected by remote metastases from many primary tumors. The surgical resection of isolated pulmonary metastases represents an important and effective element of therapy. This is a retrospective study about our entire experience with pulmonary resection for metastatic cancer using 1318-nm neodymium-doped yttrium-aluminum garnet laser. In this single-institution study, we retrospectively analyzed a group of 209 patients previously treated for primary malignant solid tumors. We excluded 103 patients. The number and location of lesions in the lungs was determined using chest computed tomography and positron emission tomography-computed tomography. Disseminated malignancy was excluded. All pulmonary laser resections are performed via an anteroaxillary muscle-sparing thoracotomy. All lesions were routinely removed by laser with a small (5-10 mm) margin of the healthy lung. Patients received systematic lymph node sampling with intraoperative smear cytology of sampled lymph nodes. Mortality at 2 years from the first surgery is around 20% (10% annually). This value increases to 45% in the third year. The estimated median survival for patients who underwent the first surgery is reported to be approximately 42 months. Our results show that laser resection of lung metastases can achieve good result, in terms of radical resection and survival, as conventional surgical metastasectomy. The great advantage is the possibility of limiting the damage to the lung. Stapler resection of a high number of metastases would mutilate the lung.

Beneficial Effect of Low Fluence 1,064 nm Q-Switched Neodymium:Yttrium-Aluminum-Garnet Laser in the Treatment of Senile Lentigo

PubMed Central

Nam, Jae-Hui; Kim, Han-Saem; Lee, Ga-Young

2017-01-01

Background Low fluence 1,064 nm Q-switched (QS) Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) laser treatment, also known as laser toning, is widely used for pigmentary disorders. There has been no reliable evaluation of the effect of low fluence 1,064 nm QS Nd:YAG laser for senile lentigo. Objective To investigate the beneficial effect of low fluence 1,064 nm QS Nd:YAG laser in the treatment of senile lentigo on the face. Methods A retrospective review was conducted on patients treated only with repetitive low fluence 1,064 nm QS Nd:YAG laser. Among them, 12 patients with multiple senile lentigines before treatment were included. All side effects were recorded to assess the safety of the modality. Results Mean age was 56.1±7.8 years old and male-to-female ratio was 1:11. Mean treatment fluence was 1.62±0.16 J/cm2 and mean total treatment session was 8.8±2.6. Mean interval period between each session was 28.0±11.4 days and mean treatment session to reach marked and near total improvement was 8.7±2.8. At the final visit, seven of 12 (58.3%) patients reached marked and near total improvement, and three of 12 (25.0%) reached moderate improvement. No side effects occurred. Conclusion Repetitive low fluence 1,064 nm QS Nd:YAG laser treatment may be an effective and safe optional modality for senile lentigo. PMID:28761290

Aging Effects on the Structural and Magnetic Properties of Terbium-Aluminium Co-doping of Yttrium Iron Garnet Films Prepared Using the Sol-Gel Method

NASA Astrophysics Data System (ADS)

Aldbea, Ftema W.; Yusrianto, Efil; Ibrahim, N. B.

2018-06-01

The terbium-aluminium co-doped yttrium iron garnet (Tb0.2Y2.8Al1Fe4O12) nanoparticles films, prepared via a sol-gel method, were aged variously for 2 days, 3 days, 4 days and 5 days. The films were deposited on quartz substrates using a spin coating technique then annealed at 900°C in air for 2 h. The microstructural and magnetic properties of the films were measured using an x-ray diffractometer (XRD), a field emission scanning electron microscope and a vibrating sample magnetometer. The XRD results showed that all the resultant films were a single phase regardless of aging time. A change in the lattice parameter's behavior was observed at the longer aging times. At an aging time of 5 days, the films became highly agglomerated and exhibited the greatest thickness value of 458.9 nm. The saturation magnetization, M s, of the films decreased from 31 kA/m to 6 kA/m as the aging time was increased from 2 days to 5 days, due to the increasing Fe-O bond length resulting from larger grain sizes. The increase in aging time to 5 days caused a reduction in the coercivity, H c, of films due to the multi-domain formation.

Low Thermal Conductivity Yttrium Aluminum Garnet Thermal Barrier Coatings Made by the Solution Precursor Plasma Spray: Part II—Planar Pore Formation and CMAS Resistance

NASA Astrophysics Data System (ADS)

Kumar, Rishi; Jiang, Chen; Wang, Jiwen; Cietek, Drew; Roth, Jeffery; Gell, Maurice; Jordan, Eric H.

2018-06-01

Low thermal conductivity in yttrium aluminum garnet (YAG)-based thermal barrier coatings (TBCs) made by solution precursor plasma spray (SPPS) can be achieved by creating planar arrays of porosity called inter-pass boundaries (IPBs) as shown in Part I. In the current work, the mechanism of IPBs formation is studied through analysis of precursor entrainment and collection of single/raster step deposition patterns. It is concluded that the IPBs are formed by trapping precursor that under/over penetrates the plasma jet. CMAS interaction tests on SPPS YAG TBCs with heavy IPBs show an improvement of 123X and 15X over APS YSZ and SPPS YAG-light IPBs TBCs, respectively. It is demonstrated that the exceptional coating performance is because of the engineered heavy IPBs which branch out from the vertical cracks and run parallel to the surface. The CMAS melt gets drawn in the IPBs due to the capillary forces, leading to a shallow infiltration depth. The IPBs have a porosity of 70%, thus act as reservoirs for CMAS. Based on the favorable results, an alternate CMAS mitigation strategy is proposed that solely relies on microstructural features instead of the conventional approach where a vigorous reaction between CMAS-TBCs is desirable to form secondary phases.

Carbon footprint assessment of recycling technologies for rare earth elements: A case study of recycling yttrium and europium from phosphor.

PubMed

Hu, Allen H; Kuo, Chien-Hung; Huang, Lance H; Su, Chao-Chin

2017-02-01

Rare earth elements are key raw materials in high-technology industries. Mining activities and manufacturing processes of such industries have caused considerable environmental impacts, such as soil erosion, vegetation destruction, and various forms of pollution. Sustaining the long-term supply of rare earth elements is difficult because of the global shortage of rare earth resources. The diminishing supply of rare earth elements has attracted considerable concern because many industrialized countries regarded such elements as important strategic resources for economic growth. This study aims to explore the carbon footprints of yttrium and europium recovery techniques from phosphor. Two extraction recovery methods, namely, acid extraction and solvent extraction, were selected for the analysis and comparison of carbon footprints. The two following functional units were used: (1) the same phosphor amounts for specific Y and Eu recovery concentrations, and (2) the same phosphor amounts for extraction. For acid extraction method, two acidic solutions (H 2 SO 4 and HCl) were used at two different temperatures (60 and 90°C). For solvent extraction method, acid leaching was performed followed by ionic liquid extraction. Carbon footprints from acid and solvent extraction methods were estimated to be 10.1 and 10.6kgCO 2 eq, respectively. Comparison of the carbon emissions of the two extraction methods shows that the solvent extraction method has significantly higher extraction efficiency, even though acid extraction method has a lower carbon footprint. These results may be used to develop strategies for life cycle management of rare earth resources to realize sustainable usage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Yttrium-90 Resin Microsphere Radioembolization Using an Antireflux Catheter: An Alternative to Traditional Coil Embolization for Nontarget Protection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morshedi, Maud M., E-mail: maud.morshedi@my.rfums.org; Bauman, Michael, E-mail: mbauman@ucsd.edu; Rose, Steven C., E-mail: scrose@ucsd.edu

2015-04-15

PurposeSerious complications can result from nontarget embolization during yttrium-90 (Y-90) transarterial radioembolization. Hepatoenteric artery coil embolization has been traditionally performed to prevent nontarget radioembolization. The U.S. Food and Drug Administration–approved Surefire Infusion System (SIS) catheter, designed to prevent reflux, is an alternative to coils. The hypothesis that quantifiable SIS procedural parameters are comparable to coil embolization was tested.MethodsFourteen patients aged 36–79 years with colorectal, neuroendocrine, hepatocellular, and other predominantly bilobar hepatic tumors who underwent resin microsphere Y-90 radioembolization using only the SIS catheter (n = 7) versus only detachable coils (n = 7) for nontarget protection were reviewed retrospectively. Procedure time, fluoroscopy time, contrast dose,more » radiation dose, and cost were evaluated.ResultsMultivariate analysis identified significant cohort differences in the procedural parameters evaluated (F(10, 3) = 10.39, p = 0.04). Between-group comparisons of the pretreatment planning procedure in the SIS catheter group compared to the coil embolization group demonstrated a significant reduction in procedure time (102.6 vs. 192.1 min, respectively, p = 0.0004), fluoroscopy time (14.3 vs. 49.7 min, respectively, p = 0.0016), and contrast material dose (mean dose of 174.3 vs. 265.0 mL, respectively, p = 0.0098). Procedural parameters were not significantly different between the two groups during subsequent dose delivery procedures. Overall cost of combined first-time radioembolization procedures was significantly less in the SIS group ($4252) compared to retrievable coil embolization ($11,123; p = 0.001).ConclusionThe SIS catheter results in a reduction in procedure time, fluoroscopy time, and contrast material dose and may be an attractive cost-effective alternative to detachable coil embolization for prevention of nontarget radioembolization.« less

Thulium-yttrium-aluminium-garnet (Tm:YAG) laser treatment of penile cancer: oncological results, functional outcomes, and quality of life.

PubMed

Musi, Gennaro; Russo, Andrea; Conti, Andrea; Mistretta, Francesco A; Di Trapani, Ettore; Luzzago, Stefano; Bianchi, Roberto; Renne, Giuseppe; Ramoni, Stefano; Ferro, Matteo; Matei, Deliu Victor; Cusini, Marco; Carmignani, Luca; de Cobelli, Ottavio

2018-02-01

To evaluate the oncological and functional outcomes of patients diagnosed with penile cancer undergoing conservative treatment through thulium-yttrium-aluminium-garnet (Tm:YAG) laser ablation. Twenty-six patients with a penile lesion underwent ablation with a RevoLix 200 W continuous-wave laser. The procedure was carried out with a pen-like laser hand piece, using a 360 μm laser fiber and 15-20 W of power. Median (IQR) follow-up time was 24 (15-30) months. Recurrence rate and post-operative sexual function were assessed. Median age at surgery was 61 years. Median (inter quartile range) size of the lesions was 15 [10-20] mm. Overall, 11 (47.8%) and 12 (52.2%) at the final pathology presented in situ and invasive squamous cell carcinoma (SCC), respectively. The final pathological stage was pTis, pT1a, pT2, and pT3 in 11 (47.8%), 7 (30.4%), 3 (13.0%), and 2 (8.7%) patients, respectively. Moreover, four (17.4%) patients had a recurrence of which three (13.0%) and one (4.3%) patients developed an invasive or in situ recurrence, respectively. After treatment 6 (26.1%) patients reported a conserved penile sensitivity, while 13 (56.5%) and 4 (17.4%) patients experienced a better or worse sensitivity after ablation, respectively. Post-treatment sexual activity was achieved within the first month after laser ablation in 82.6% of the patients. Early stage penile carcinomas can be effectively treated with an organ preservation strategy. Tm:YAG conservative laser treatment is easy, safe and offers good functional outcome, with a minor impact on patient's quality of life.

Factors associated with increased incidence of severe toxicities following yttrium-90 resin microspheres in the treatment of hepatic malignancies.

PubMed

Roberson Ii, John D; McDonald, Andrew M; Baden, Craig J; Lin, Chee Paul; Jacob, Rojymon; Burnett Iii, Omer L

2016-03-14

To further define variables associated with increased incidences of severe toxicities following administration of yttrium-90 ((90)Y) microspheres. Fifty-eight patients undergoing 79 treatments were retrospectively assessed for development of clinical and laboratory toxicity incidence following (90)Y administration. Severe toxicity events were defined using Common Terminology Criteria for Adverse Events version 4.03 and defined as grade ≥ 3. Univariate logistic regression analyses were used to evaluate the effect of different factors on the incidence of severe toxicity events. Multicollinearity was assessed for all factors with P < 0.1 using Pearson correlation matrices. All factors not excluded due to multicollinearity were included in a multivariate logistic regression model for each measurement of severe toxicity. Severe (grade ≥ 3) toxicities occurred following 21.5% of the 79 treatments included in our analysis. The most common severe laboratory toxicities were severe alkaline phosphatase (17.7%), albumin (12.7%), and total bilirubin (10.1%) toxicities. Decreased pre-treatment albumin (OR = 26.2, P = 0.010) and increased pre-treatment international normalized ratio (INR) (OR = 17.7, P = 0.048) were associated with development of severe hepatic toxicity. Increased pre-treatment aspartate aminotransferase (AST; OR = 7.4, P = 0.025) and decreased pre-treatment hemoglobin (OR = 12.5, P = 0.025) were associated with severe albumin toxicity. Increasing pre-treatment model for end-stage liver disease (MELD) score (OR = 1.8, P = 0.033) was associated with severe total bilirubin toxicity. Colorectal adenocarcinoma histology was associated with severe alkaline phosphatase toxicity (OR = 5.4, P = 0.043). Clinicians should carefully consider pre-treatment albumin, INR, AST, hemoglobin, MELD, and colorectal histology when choosing appropriate candidates for (90)Y microsphere therapy.

Process for removing carbon from uranium

DOEpatents

Powell, George L.; Holcombe, Jr., Cressie E.

1976-01-01

Carbon contamination is removed from uranium and uranium alloys by heating in inert atmosphere to 700.degree.-1900.degree.C in effective contact with yttrium to cause carbon in the uranium to react with the yttrium. The yttrium is either in direct contact with the contaminated uranium or in indirect contact by means of an intermediate transport medium.

Development and performance test of an online blood sampling system for determination of the arterial input function in rats.

PubMed

Roehrbacher, Friedrich; Bankstahl, Jens P; Bankstahl, Marion; Wanek, Thomas; Stanek, Johann; Sauberer, Michael; Muellauer, Julia; Schroettner, Thales; Langer, Oliver; Kuntner, Claudia

2015-12-01

For positron emission tomography (PET) kinetic modelling, an accurate determination of the arterial input function is required. In this study, a blood sampling system was developed and tested using different radiotracers in rats. The detector consists of pairs of lutetium yttrium oxyorthosilicate (LYSO) detectors, photomultiplier tubes and lead shield assembled within a steel casing working in coincidence mode. Rats were cannulated with microtubes in the femoral artery and vein for arterial blood sampling as well as administration of the PET tracers. Connected PTFE microtubes were centred between the LYSO crystals using a special holder. To enhance sensitivity, three layers with two coils were used. A flexible tube pump was used to ensure a constant blood flow. Performance of the detector was assessed with [(18)F]fludeoxyglucose (FDG), [(18)F]ciprofloxacin, (R)-[(11)C]verapamil, [(11)C]tariquidar, [(11)C]mephobarbital and [(11)C]MC113. Obtained input function curves were compared with manual samples drawn every 5 s during the first 3 min and further on at 5, 10, 20, 30, 40, 50 and 60 min after radiotracer injection. After manual sampling, an arterio/venous shunt was established. Shape and area-under-the-curve (AUC; Bq/μl*h) of the input functions were evaluated. The developed detector system provided an absolute sensitivity of 6.5%. Maximum peak values agreed well between manual samples and the detector with a mean difference of -0.4% ± 7.0% (max 12.0%, min -9.9%). AUC values also exhibited an excellent correlation (R = 0.996) between manual sampling and detector measurements with a mean difference of 9.3% ± 9.7% (max 24.1%, min -3.2%). The system was able to measure peak blood activity concentration levels of 110 to 2,000 Bq/μl which corresponds to injected activities from 5.5 to 100 MBq depending on the used radiotracer, applied volume and weight of the animal. This study demonstrates that the developed blood sampling system can be used for

Dietary Components Affect the Plasma and Tissue Levels of Lutein in Aged Rats with Lutein Deficiency--A Repeated Gavage and Dietary Study.

PubMed

Sheshappa, Mamatha Bangera; Ranganathan, Arunkumar; Bhatiwada, Nidhi; Talahalli, Ramprasad Ravichandra; Vallikannan, Baskaran

2015-10-01

The aim of this study was to find out the influence of selected dietary components on plasma and tissue response of repeated micellar and dietary lutein in aged rats with lutein deficiency. In repeated (16 d) gavage study, micellar lutein was co-ingested with either phosphatidylcholine (PC), lyso-phosphatidylcholine (lysoPC), β-carotene, dietary fiber or vegetable fat (3% soybean oil). In dietary study, rats were fed (4 wk) semi-synthetic diet either with lutein + PC, lutein + dietary fiber or B. alba (lutein source) + PC. The post-prandial plasma and tissue response of lutein was measured by HPLC. Results showed that micellar fat, PC and lysoPC significantly (P ≤ 0.05) increased the lutein levels in plasma (31.1%, 26.8%, and 34.9%), liver (27.4%, 29.5%, and 8.6%), and eyes (63.5%, 90.2%, and 86%) compared to the control group (group gavaged micelles with no dietary components studied). Similarly, dietary study showed an enhanced plasma, liver, and eye lutein levels by 44.8%, 24.1%, and 42.0% (lutein + PC group) and 51.7%, 39.8%, and 31.7% (B.alba + PC group), respectively compared to control. The activity of antioxidant enzymes in plasma and liver of both the studies were also affected compared to control. Result reveals, that PC enhance the intestinal absorption of both micellar and dietary lutein which is either in free or bound form with food matrices in aged rats with lutein deficiency. Hence, PC at a concentration used in this study can be considered to improve the lutein bioavailability in lutein deficiency. Lutein and zeaxanthin are macular pigments acquired mostly from greens, that play an significant role in protecting vision from Age related macular degeneration (AMD). However, their biological availability is poor and affected by dietary components. This study demonstrates the positive influence of dietary PC and lyso PC in improving intestinal uptake of lutein. Our previous and present finding shows there is a possibility of developing functional

A DOI Detector With Crystal Scatter Identification Capability for High Sensitivity and High Spatial Resolution PET Imaging.

PubMed

Gu, Z; Prout, D L; Silverman, R W; Herman, H; Dooraghi, A; Chatziioannou, A F

2015-06-01

A new phoswich detector is being developed at the Crump Institute, aiming to provide improvements in sensitivity, and spatial resolution for PET. The detector configuration is comprised of two layers of pixelated scintillator crystal arrays, a glass light guide and a light detector. The annihilation photon entrance (top) layer is a 48 × 48 array of 1.01 × 1.01 × 7 mm 3 LYSO crystals. The bottom layer is a 32 × 32 array of 1.55 × 1.55 × 9 mm 3 BGO crystals. A tapered, multiple-element glass lightguide is used to couple the exit end of the BGO crystal array (52 × 52 mm 2 ) to the photosensitive area of the Position Sensitive Photomultiplier Tube (46 × 46 mm 2 ), allowing the creation of flat panel detectors without gaps between the detector modules. Both simulations and measurements were performed to evaluate the characteristics and benefits of the proposed design. The GATE Monte Carlo simulation indicated that the total fraction of the cross layer crystal scatter (CLCS) events in singles detection mode for this detector geometry is 13.2%. The large majority of these CLCS events (10.1% out of 13.2%) deposit most of their energy in a scintillator layer other than the layer of first interaction. Identification of those CLCS events for rejection or correction may lead to improvements in data quality and imaging performance. Physical measurements with the prototype detector showed that the LYSO, BGO and CLCS events were successfully identified using the delayed charge integration (DCI) technique, with more than 95% of the LYSO and BGO crystal elements clearly resolved. The measured peak-to-valley ratios (PVR) in the flood histograms were 3.5 for LYSO and 2.0 for BGO. For LYSO, the energy resolution ranged from 9.7% to 37.0% full width at half maximum (FWHM), with a mean of 13.4 ± 4.8%. For BGO the energy resolution ranged from 16.0% to 33.9% FWHM, with a mean of 18.6 ± 3.2%. In conclusion, these results demonstrate that the proposed detector is feasible and can

A DOI Detector With Crystal Scatter Identification Capability for High Sensitivity and High Spatial Resolution PET Imaging

PubMed Central

Gu, Z.; Prout, D. L.; Silverman, R. W.; Herman, H.; Dooraghi, A.; Chatziioannou, A. F.

2015-01-01

A new phoswich detector is being developed at the Crump Institute, aiming to provide improvements in sensitivity, and spatial resolution for PET. The detector configuration is comprised of two layers of pixelated scintillator crystal arrays, a glass light guide and a light detector. The annihilation photon entrance (top) layer is a 48 × 48 array of 1.01 × 1.01 × 7 mm3 LYSO crystals. The bottom layer is a 32 × 32 array of 1.55 × 1.55 × 9 mm3 BGO crystals. A tapered, multiple-element glass lightguide is used to couple the exit end of the BGO crystal array (52 × 52 mm2) to the photosensitive area of the Position Sensitive Photomultiplier Tube (46 × 46 mm2), allowing the creation of flat panel detectors without gaps between the detector modules. Both simulations and measurements were performed to evaluate the characteristics and benefits of the proposed design. The GATE Monte Carlo simulation indicated that the total fraction of the cross layer crystal scatter (CLCS) events in singles detection mode for this detector geometry is 13.2%. The large majority of these CLCS events (10.1% out of 13.2%) deposit most of their energy in a scintillator layer other than the layer of first interaction. Identification of those CLCS events for rejection or correction may lead to improvements in data quality and imaging performance. Physical measurements with the prototype detector showed that the LYSO, BGO and CLCS events were successfully identified using the delayed charge integration (DCI) technique, with more than 95% of the LYSO and BGO crystal elements clearly resolved. The measured peak-to-valley ratios (PVR) in the flood histograms were 3.5 for LYSO and 2.0 for BGO. For LYSO, the energy resolution ranged from 9.7% to 37.0% full width at half maximum (FWHM), with a mean of 13.4 ± 4.8%. For BGO the energy resolution ranged from 16.0% to 33.9% FWHM, with a mean of 18.6 ± 3.2%. In conclusion, these results demonstrate that the proposed detector is feasible and can

A DOI Detector With Crystal Scatter Identification Capability for High Sensitivity and High Spatial Resolution PET Imaging

NASA Astrophysics Data System (ADS)

Gu, Z.; Prout, D. L.; Silverman, R. W.; Herman, H.; Dooraghi, A.; Chatziioannou, A. F.

2015-06-01

A new phoswich detector is being developed at the Crump Institute, aiming to provide improvements in sensitivity, and spatial resolution for PET. The detector configuration is comprised of two layers of pixelated scintillator crystal arrays, a glass lightguide and a light detector. The annihilation photon entrance (top) layer is a 48×48 array of 1.01 × 1.01 × 7 mm3 LYSO crystals. The bottom layer is a 32 × 32 array of 1.55 × 1.55 × 9 mm3 BGO crystals. A tapered, multiple-element glass lightguide is used to couple the exit end of the BGO crystal array (52 × 52 mm2) to the photosensitive area of the Position Sensitive Photomultiplier Tube (46 × 46 mm2), allowing the creation of flat panel detectors without gaps between the detector modules. Both simulations and measurements were performed to evaluate the characteristics and benefits of the proposed design. The GATE Monte Carlo simulation indicated that the total fraction of the cross layer crystal scatter (CLCS) events in singles detection mode for this detector geometry is 13.2%. The large majority of these CLCS events (10.1% out of 13.2%) deposit most of their energy in a scintillator layer other than the layer of first interaction. Identification of those CLCS events for rejection or correction may lead to improvements in data quality and imaging performance. Physical measurements with the prototype detector showed that the LYSO, BGO and CLCS events were successfully identified using the delayed charge integration (DCI) technique, with more than 95% of the LYSO and BGO crystal elements clearly resolved. The measured peak-to-valley ratios (PVR) in the flood histograms were 3.5 for LYSO and 2.0 for BGO. For LYSO, the energy resolution ranged from 9.7% to 37.0% full width at half maximum (FWHM), with a mean of 13.4 ± 4.8%. For BGO the energy resolution ranged from 16.0% to 33.9% FWHM, with a mean of 18.6 ± 3.2%. In conclusion, these results demonstrate that the proposed detector is feasible and can

Optimized anion exchange column isolation of zirconium-89 (89Zr) from yttrium cyclotron target: Method development and implementation on an automated fluidic platform.

PubMed

O'Hara, Matthew J; Murray, Nathaniel J; Carter, Jennifer C; Morrison, Samuel S

2018-04-13

Zirconium-89 ( 89 Zr), produced by the (p, n) reaction from naturally monoisotopic yttrium ( nat Y), is a promising positron emitting isotope for immunoPET imaging. Its long half-life of 78.4 h is sufficient for evaluating slow physiological processes. A prototype automated fluidic system, coupled to on-line and in-line detectors, has been constructed to facilitate development of new 89 Zr purification methodologies. The highly reproducible reagent delivery platform and near-real time monitoring of column effluents allows for efficient method optimization. The separation of Zr from dissolved Y metal targets was evaluated using several anion exchange resins. Each resin was evaluated against its ability to quantitatively capture Zr from a load solution high in dissolved Y. The most appropriate anion exchange resin for this application was identified, and the separation method was optimized. The method is capable of a high Y decontamination factor (>10 5 ) and has been shown to remove Fe, an abundant contaminant in Y foils, from the 89 Zr elution fraction. Finally, the method was evaluated using cyclotron bombarded Y foil targets; the method was shown to achieve >95% recovery of the 89 Zr present in the foils. The anion exchange column method described here is intended to be the first 89 Zr isolation stage in a dual-column purification process. Copyright © 2018 Elsevier B.V. All rights reserved.

Optimized anion exchange column isolation of zirconium-89 ( 89Zr) from yttrium cyclotron target: Method development and implementation on an automated fluidic platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

O’Hara, Matthew J.; Murray, Nathaniel J.; Carter, Jennifer C.

Zirconium-89 ( 89Zr), produced by the (p, n) reaction from naturally monoisotopic yttrium ( natY), is a promising positron emitting isotope for immunoPET imaging. Its long half-life of 78.4 h is sufficient for evaluating slow physiological processes. A prototype automated fluidic system, coupled to on-line and in-line detectors, has been constructed to facilitate development of new 89Zr purification methodologies. The highly reproducible reagent delivery platform and near-real time monitoring of column effluents allows for efficient method optimization. The separation of Zr from dissolved Y metal targets was evaluated using several anion exchange resins. Each resin was evaluated against its abilitymore » to quantitatively capture Zr from a load solution high in dissolved Y. The most appropriate anion exchange resin for this application was identified, and the separation method was optimized. The method is capable of a high Y decontamination factor (>10 5) and has been shown to remove Fe, an abundant contaminant in Y foils, from the 89Zr elution fraction. Finally, the method was evaluated using cyclotron bombarded Y foil targets; the method was shown to achieve >95% recovery of the 89Zr present in the foils. The anion exchange column method described here is intended to be the first 89Zr isolation stage in a dual-column purification process.« less

Optimized anion exchange column isolation of zirconium-89 ( 89Zr) from yttrium cyclotron target: Method development and implementation on an automated fluidic platform

DOE PAGES

O’Hara, Matthew J.; Murray, Nathaniel J.; Carter, Jennifer C.; ...

2018-02-24

Zirconium-89 ( 89Zr), produced by the (p, n) reaction from naturally monoisotopic yttrium ( natY), is a promising positron emitting isotope for immunoPET imaging. Its long half-life of 78.4 h is sufficient for evaluating slow physiological processes. A prototype automated fluidic system, coupled to on-line and in-line detectors, has been constructed to facilitate development of new 89Zr purification methodologies. The highly reproducible reagent delivery platform and near-real time monitoring of column effluents allows for efficient method optimization. The separation of Zr from dissolved Y metal targets was evaluated using several anion exchange resins. Each resin was evaluated against its abilitymore » to quantitatively capture Zr from a load solution high in dissolved Y. The most appropriate anion exchange resin for this application was identified, and the separation method was optimized. The method is capable of a high Y decontamination factor (>10 5) and has been shown to remove Fe, an abundant contaminant in Y foils, from the 89Zr elution fraction. Finally, the method was evaluated using cyclotron bombarded Y foil targets; the method was shown to achieve >95% recovery of the 89Zr present in the foils. The anion exchange column method described here is intended to be the first 89Zr isolation stage in a dual-column purification process.« less

Partial synthesis of ganglioside and lysoganglioside lipoforms as internal standards for MS quantification.

PubMed

Gantner, Martin; Schwarzmann, Günter; Sandhoff, Konrad; Kolter, Thomas

2014-12-01

Within recent years, ganglioside patterns have been increasingly analyzed by MS. However, internal standards for calibration are only available for gangliosides GM1, GM2, and GM3. For this reason, we prepared homologous internal standards bearing nonnatural fatty acids of the major mammalian brain gangliosides GM1, GD1a, GD1b, GT1b, and GQ1b, and of the tumor-associated gangliosides GM2 and GD2. The fatty acid moieties were incorporated after selective chemical or enzymatic deacylation of bovine brain gangliosides. For modification of the sphingoid bases, we developed a new synthetic method based on olefin cross metathesis. This method was used for the preparation of a lyso-GM1 and a lyso-GM2 standard. The total yield of this method was 8.7% for the synthesis of d17:1-lyso-GM1 from d20:1/18:0-GM1 in four steps. The title compounds are currently used as calibration substances for MS quantification and are also suitable for functional studies. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

Comparative evaluation of photoablative efficacy of erbium: yttrium-aluminium-garnet and diode laser for the treatment of gingival hyperpigmentation. A randomized split-mouth clinical trial.

PubMed

Giannelli, Marco; Formigli, Lucia; Bani, Daniele

2014-04-01

The use of lasers in periodontology is a matter of debate, mainly because of the lack of consensual therapeutic protocols. In this randomized, split-mouth trial, the clinical efficacy of two different photoablative dental lasers, erbium:yttrium-aluminum-garnet (Er:YAG) and diode, for the treatment of gingival hyperpigmentation is compared. Twenty-one patients requiring treatment for mild-to-severe gingival hyperpigmentation were enrolled. Maxillary or mandibular left or right quadrants were randomly subjected to photoablative deepithelialization with either Er:YAG or diode laser. Masked clinical assessments of each laser quadrant were made at admission and days 7, 30, and 180 postoperatively by an independent observer. Histologic examination was performed before and soon after treatment and 6 months after irradiation. Patients also compiled a subjective evaluation questionnaire. Both diode and Er:YAG lasers gave excellent results in gingival hyperpigmentation. However, Er:YAG laser induced deeper gingival tissue injury than diode laser, as judged by bleeding at surgery, delayed healing, and histopathologic analysis. The use of diode laser showed additional advantages compared to Er:YAG in terms of less postoperative discomfort and pain. This study highlights the efficacy of diode laser for photoablative deepithelialization of hyperpigmented gingiva. It is suggested that this laser can represent an effective and safe therapeutic option for gingival photoablation.

Short-pulse neodymium:yttrium-aluminium garnet (Nd:YAG 1064nm) laser irradiation photobiomodulates mitochondria activity and cellular multiplication of Paramecium primaurelia (Protozoa).

PubMed

Amaroli, Andrea; Benedicenti, Alberico; Ravera, Silvia; Parker, Steven; Selting, Wayne; Panfoli, Isabella; Benedicenti, Stefano

2017-10-01

Few studies exist to explore the potential photobiomodulation (PBM) effect of neodymium:yttrium-aluminium garnet (Nd:YAG) laser irradiation using a flat-top handpiece delivery system. In this study, we explored the photobiomodulation effect of that laser, on Paramecium primaurelia. The parameters for the different study groups were: 0.50W, 10Hz, 100msp, 30J/cm 2 ; 0.75W, 10Hz, 100msp, 45J/cm 2 ; 1.00W, 10Hz, 100msp, 60J/cm 2 ; 1.25W, 10Hz, 100msp, 75J/cm 2 and 1.50W, 10Hz, 100msp, 90J/cm 2 . Our results suggest that only the parameter 0.5W, 10Hz, 100msp, 30J/cm 2 positively photobiomodulates the Paramecium cells inducing an increment in oxygen consumption, endogenous ATP synthesis and fission rate rhythm. Applying the laser energy with parameters of 1.25W, 10Hz, 100msp, 75J/cm 2 and 1.50W, 10Hz, 100msp, 90J/cm 2 , induce adverse effect on the Paramecium cells, which protect themselves through the increase in Heat Shock Protein-70 (HSP70). The data presented in our work support our assumption that, when using appropriate parameters of irradiation, the 1064nm Nd:YAG laser with flat-top handpiece could be a valuable aid for effective clinical application of PBM. Copyright © 2017 Elsevier GmbH. All rights reserved.

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications.

PubMed

Verma, Mahesh; Kumari, Pooja; Gupta, Rekha; Gill, Shubhra; Gupta, Ankur

2015-01-01

Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique. Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3-0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine. The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer. Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength. Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

The role of yttrium and titanium during the development of ODS ferritic steels obtained through the STARS route: TEM and XAS study

NASA Astrophysics Data System (ADS)

Ordás, Nerea; Gil, Emma; Cintins, Arturs; de Castro, Vanessa; Leguey, Teresa; Iturriza, Iñigo; Purans, Juris; Anspoks, Andris; Kuzmin, Alexei; Kalinko, Alexandr

2018-06-01

Oxide Dispersion Strengthened Ferritic Steels (ODS FS) are candidate materials for structural components in future fusion reactors. Their high strength and creep resistance at elevated temperatures and their good resistance to neutron radiation damage is obtained through extremely fine microstructures containing a high density of nanometric precipitates, generally yttrium and titanium oxides. This work shows transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) characterization of Fe-14Cr-2W-0.3Ti-0.24Y ODS FS obtained by the STARS route (Surface Treatment of gas Atomized powder followed by Reactive Synthesis), an alternative method to obtain ODS alloys that avoids the mechanical alloying to introduce Y2O3 powder particles. In this route, FS powders already containing Ti and Y, precursors of the nanometric oxides, are obtained by gas atomization. Then, a metastable Cr- and Fe-rich oxide layer is formed on the surface of the powder particles. During consolidation by HIP at elevated temperatures, and post-HIP heat treatments above the HIP temperature, this oxide layer at Prior Particle Boundaries (PPBs) dissociates, the oxygen diffuses, and Y-Ti-O nano-oxides precipitate in the ferritic matrix. TEM characterization combined with XAFS and XANES analyses have proven to be suitable tools to follow the evolution of the nature of the different oxides present in the material during the whole processing route and select appropriate HIP and post-HIP parameters to promote profuse and fine Y-Ti-O nanometric precipitates.

Effect of annealing temperature on surface morphology and ultralow ferromagnetic resonance linewidth of yttrium iron garnet thin film grown by rf sputtering

NASA Astrophysics Data System (ADS)

Cao Van, Phuoc; Surabhi, Srivathsava; Dongquoc, Viet; Kuchi, Rambabu; Yoon, Soon-Gil; Jeong, Jong-Ryul

2018-03-01

We report high-quality yttrium-iron-garnet (YIG; Y3Fe5O12) ultrathin films grown on {111} gadolinium-gallium-garnet (GGG; Gd3Ga5O12) substrates using RF sputtering deposition on an off-stoichiometric target and optimized thermal treatments. We measured a narrow peak-to-peak ferromagnetic resonance linewidth (ΔH) whose minimum value was 1.9 Oe at 9.43 GHz for a 60-nm-thick YIG film. This value is comparable to the most recently published value for a YIG thin film grown by pulsed laser deposition. The temperature dependence of the ΔH was investigated systematically, the optimal annealing condition for our growing condition was 875 °C. Structural analysis revealed that surface roughness and crystallinity played an important role in the observed ΔH broadening. Furthermore, the thickness dependence of the ΔH, which indicated that 60 nm thickness was optimal to obtain narrow ΔH YIG films, was also investigated. The thickness dependence of ΔH was understood on the basis of contributions of surface-associated magnon scattering and magnetic inhomogeneities to the ΔH broadening. Other techniques such as transmission electron microscopy, scanning electron microscopy, and X-ray diffraction were used to study the crystalline structure of the YIG films. The high quality of the films in terms of their magnetic properties was expressed through a very low coercivity and high saturation magnetization measured using a vibration sample magnetometer.

Early Dose Response to Yttrium-90 Microsphere Treatment of Metastatic Liver Cancer by a Patient-Specific Method Using Single Photon Emission Computed Tomography and Positron Emission Tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Janice M.; Department of Radiation Oncology, Wayne State University, Detroit, MI; Wong, C. Oliver

2009-05-01

Purpose: To evaluate a patient-specific single photon emission computed tomography (SPECT)-based method of dose calculation for treatment planning of yttrium-90 ({sup 90}Y) microsphere selective internal radiotherapy (SIRT). Methods and Materials: Fourteen consecutive {sup 90}Y SIRTs for colorectal liver metastasis were retrospectively analyzed. Absorbed dose to tumor and normal liver tissue was calculated by partition methods with two different tumor/normal liver vascularity ratios: an average 3:1 and a patient-specific ratio derived from pretreatment technetium-99m macroaggregated albumin SPECT. Tumor response was quantitatively evaluated from fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography scans. Results: Positron emission tomography showed a significant decrease in total tumor standardizedmore » uptake value (average, 52%). There was a significant difference in the tumor absorbed dose between the average and specific methods (p = 0.009). Response vs. dose curves fit by linear and linear-quadratic modeling showed similar results. Linear fit r values increased for all tumor response parameters with the specific method (+0.20 for mean standardized uptake value). Conclusion: Tumor dose calculated with the patient-specific method was more predictive of response in liver-directed {sup 90}Y SIRT.« less