1,196 research outputs found
Hepatopancreas is the extraovarian site of vitellogenin synthesis in black tiger shrimp, Penaeus monodon.
No full textPolymeric micelles and the Dy-166/Ho-166 generator: A study of the loading mechanism of Dy/Dy-166 and Ho-166 into PCL-b-PEO polymeric micelles for imaging and cancer treatment
No full textA radioisotope used in radionuclide therapy is Holmium-166 (Ho-166). The treatment effectiveness of Ho-166 could be improved by the use of a so called in vivo Dysprosium-166(Dy-166)/Ho-166 generator. The application of this generator is hindered by an effect called internal conversion (IC). This affect can arise after the decay of Dy-166 to Ho-166, which can cause separation of Ho-166 from its carrier.Polymeric micelles might form a solution in the application of the Dy-166/Ho-166 generator in radionuclide therapy. The main goal of this thesis was to investigate and understand the loading mechanism of metallic species and polymeric micelles with a focus on the loading of Dy/Dy-166 and Ho-166. It was found that it was not effective to load metallic species (Dy/Dy-166) as free ions or as solid precipitates. Loading metallic species as aqueous hydroxides showed to be crucial for achieving a good loading and high stability. The second goal was to study if polymeric micelles were able to retain Ho-166 inside their core under the effects of internal conversion. No additional losses of Ho-166 were found when Dy/Dy-166 and Ho-166 were loaded into the micelles. It was concluded that the PCL-PEO micelles prevented the loss of Ho-166 under internal conversion effects.Applied Science
Hepatopancreas and ovary are sites of vitellogenin synthesis as determined from partial cDNA encoding of vitellogenin in the marine shrimp, Penaeus vannamei.
No full textbeta-delayed proton decays and spin assignments for Tb-140, Dy-141 and Dy-143
No full textThe proton-rich isotopes Tb-140 and Dy-141 were produced via the fusion evaporation reaction Ca-40+ Cd-106. Their beta-delayed proton decays were studied by p-gamma coincidence in combination with a He-jet tape transport system, and half-lives, proton energy spectra, gamma-transitions following the proton emission, as well as beta-delayed proton branching ratios to the low-lying states in the grand-daughter nuclei were determined. Comparing the experimental data with statistical model calculations, the ground-state spins of Tb-140 and Dy-141 were found to be consistent with 7 and 9/2, respectively. The configuration-constrained nuclear potential energy surfaces (NPES) of Tb-140 and Dy-141 were calculated using the Woods-Saxon-Strutinsky method, which suggest the ground-state spins and parities of Tb-140 and Dy-141 to be 7(+) and 9/2(-), respectively. In addition, the configuration-constrained NPES of Dy-143 were calculated, which predict a 1/2(+) ground state and a 11/2(-) isomer with excitation energy of 198 keV. These findings are consistent with our previous experimental data on Dy-143 reported in Eur. Phys. J. A 16, 347 (2003).Physics, NuclearPhysics, Particles & FieldsSCI(E)3ARTICLE137-402
Direct numerical simulation of turbulent Couette-Poiseuille flow with zero skin friction
No full textThe near-wall scaling of mean velocity U(y) is addressed for the case of zero skin friction on one wall of a fully turbulent channel flow. The present DNS results can be added to the evidence in support of the conjecture that U is proportional to √yw in the region just above the wall at which the mean shear dU/dy = 0
Iron oxide nanoparticles as carriers for the Dy-166/Ho-166 in vivo generator: A study into the characteristics and retention of Dy and Ho in iron oxide nanoparticles
No full textBackground:Cancer is one of the leading causes of death worldwide. Targeted radionuclide therapy has become a important treatment, this is when a carrier molecule is attached to a radionuclide to deliver cytotoxic radiation levels to diseased cells. β− emitters are frequently used in RNT because they have a long penetration depth, such as the dysprosium-166/holmium-166 (166Dy/166Ho) in vivo generator. The 166Dy/166Ho in vivo generator shows great potential for large tumors because of the long half-life time of the mother nuclide 166Dy and the emission of high energy β− from the daughter nuclide 166Ho. Previous research shows the release of 72 % of the 166Ho when 166Ho is bound to conventional chelators due to internal conversion after the β− decay. The aim of this thesis is to synthesize an iron oxide nanoparticle as carrier for the 166Dy/166Ho in vivo generator. This iron oxide nanoparticles (SPIONs) should prevent internal conversion and thus the loss of the daughter nuclide 166Ho.Results:The dysprosium doped iron oxide nanoparticles were synthesized successfully with an average diameter of 6.1 ± 1.5 nm, measured with TEM. The DLS and TEM results showed that the SPIONs were aggregating. The labeling efficiency represents how much Dy is retained in the Dy doped SPIONs, for the non-radioactive Dy this was measured with the ICP/OES. The labelling efficiency was 3.21 ± 0.8 %. The 166Dy doped iron oxide nanoparticles were also synthesized successfully with a radiolabelling efficiency of 3.12 ± 2.2 %, measured with a 2480 Wizard 2 Gamma counter. The retention of 166Dy + 166Ho was 79.2 ± 1.8 % after 96 h.Conclusion:The retention of 166Dy + 166Ho in iron oxide nanoparticles was 79.2±1.8 % after 96 hours. This is much higher than the retention of 28% by conventional chelators. This means that the iron oxide nanoparticls is a safer carrier for the 166Dy/166Ho in vivo generator than the conventional chelator.Applied Physic
Carrier recombination processes and divalent lanthanide spectroscopy in YPO4:Ce3+;L3+ (L=Sm,Dy,Tm)
No full textWe studied charge carrier trapping, detrapping, and recombination phenomena in Ce3+ doped YPO4, codoped with Sm3+, Dy3+, or Tm3+. Ce ions trap the holes and Sm, Dy, and Tm trap electrons created during x-ray irradiation. By means of red to infrared stimulation, the trapped electrons can be back transferred to Ce leading to shorter wavelength Ce3+?5d-4f luminescence. Excitation spectra for this recombination luminescence were recorded from 10 K to room temperature. It provides information on the excited state energies of divalent Sm, Dy, and Tm with respect to the lanthanide ground state energy and with respect to the mobility edge energy of YPO4. From the temperature dependence, insight is obtained on the carrier recombination pathways. We will identify temperature independent tunneling recombination, recombination by thermal excitation to the conduction band, and phonon-assisted delocalization of electrons from impurity states within the conduction band.QN/Quantum NanoscienceApplied Science
Study on Superdeformed Bands of Dy-152 and Its Neighboring Nuclei
No full textDy-152 is the first observed superdeformed nucleus, whose band structure reflects the typical distribution of high j low Omega orbitals of superdeformed nuclei in A similar to 150 mass region. The particle-number conserving treatment of the cranked shell model with monopole and quadrupole paring interactions is adopted to investigate the observed six superdeformed bands in Dy-152. The pi[523]7/2 orbital is emphasized for the first time to interpret the microscopic structure of band 2 and 3 of Dy-152. A new comprehension is proposed on the basis of ever existing experimental and theoretical results, and the reliability is illustrated by several superdeformed bands of neighboring nuclei.Physics, Fluids & PlasmasSCI(E)EI中国科学引文数据库(CSCD)05408-4111
Microstructure and Wear Properties of the Quasi-Rapidly Solidified NiAl/Cr(Mo,Dy) Hypoeutectic Alloy
No full textThe NiAl/Cr(Mo,Dy) hypoeutectic alloy was prepared by quasi-rapid solidification to investigate its microstructure and wear behavior. The results revealed that the quasi-rapid solidification refined the eutectic cell and NiAl/Cr(Mo) eutectic structure obviously. The alloy was composed of primary NiAl, fine NiAl/Cr(Mo) eutectic lamella and Ni (5) Dy phase. Compression test showed that the quasi-rapid solidification improved the mechanical properties of the alloy obviously. Wear test exhibited that alloy possessed excellent wear properties at about 1073 K, which should be ascribed to the lubricant film formed by amorphous and Cr (2) O (3) and Al (2) O (3) nanoparticles. The alloy also exhibited relative good wear properties at 673 K, which should be attributed to its high strength.SCI(E)EICPCI-S(ISTP)[email protected]
Magnetic properties of quadruple perovskites Ba4LnRu3O12 (Ln=La, Nd, Sm-Gd, Dy-Lu)
Full text linkQuadruple perovskites Ba4LnRu3O12 (Ln=La, Nd, Sm-Gd, Dy-Lu) were prepared and their magnetic properties were investigated. They adopt the 12L-perovskite-type structure consisting of Ru3O12 trimers and LnO6 octahedra. All of these compounds show an antiferromagnetic transition at 2.5-30 K. For Ba4NdRu3O12, ferrimagnetic ordering has been observed at 11.5 K. The observed magnetic transition is due to the magnetic behavior of the Ru^[4.33+]3O12 trimer with S=1/2. Magnetic properties of Ba4LnRu3O12 were compared with those of triple perovskites Ba3LnRu2O9 and double perovskites Ba2LnRuO6
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