0000000000344019
AUTHOR
M. Vega
Synthesis and optical characterization of Er-doped bismuth titanate nanoparticles grown by sol-gel hydrothermal method
Abstract The Er 3+ -doped bismuth titanate (Bi 4 Ti 3 O 12 , BIT) nanoparticles were synthesized by a combined sol–gel and hydrothermal method under a partial oxygen pressure of 30 bar. The composition and morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering. They showed pure and homogeneous spherical BIT nanoparticles with a size below the 30 nm. The incorporation of Er ions showed a strong decrease in the lattice parameters, as well as averaged particle size. The photoluminescence up-conversion (excitation wavelength =1480 nm) showed an enhancement of the infrared emission (980 nm) as Er concentration increased, achieving a maxi…
Modification of longitudinal relaxation time (T1) as a biomarker of patellar cartilage degeneration
Abstract Objectives To study the viability of longitudinal relaxation time ( T1 ) of patellar cartilage as a biomarker of the degree of degeneration. Material and methods We included 15 subjects classified into three groups according to clinical criteria (pain, functional limitation, and duration of symptoms) and imaging criteria as follows: (a) normal (3 men, 2 women; age 30 ± 14 years), (b) with initial degeneration of the patellar cartilage (3 men, 2 women; age 30 ± 6 years), or (c) with advanced degeneration (3 men, 2 women; age 57 ± 10 years). All underwent MRI examination using special echo-gradient sequences to segment the cartilage and calculate the T1 maps. We selected the entire c…