ABSTRACT
In the present paper, the upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2- 50PbF2 glass ceramic (GC) were studied. The GC has the following composition (in mol%): 50SiO2-50PbF2-1YbF3-0. 5HoF3. The mixtures of about 10 g were placed in a corundum crucible and melted at 1000 degrees C for 15 min in a SiC electric furnace in air and then poured on a brass plate. The GCs were obtained just by heat treatment at 450 degrees C. The X-ray diffraction pattern of the GC indicates that very small size crystals were precipitated in the precursor glass by heat treatment. The GCs have as high transmittance as glasses. The GCs have higher absorption cross section and narrower absorption peaks compared to the corresponding glasses, indicating that fluoride is doped with Ho ions. The Judd-Ofelt intensity parameters were determined from the absorption spectrum and Judd-Ofelt theory. The omega2 value is 0.17 x 10(-20) cm2 lower than that of fluoride glass ZBLA (2.28 x 10(-20) cm2), because of Ho3+ doping in PbF2 microcrystal. The intense green upconversion light was observed in Ho3+/Yb3+ co-doped 50SiO2-50PbF2 GCs excited by 980 nm laser diode. A main emission band centered around 540 nm (green), and three week emission bands centered around 420 nm(violet), 480 nm (blue), and 650 nm (red) which correspond to the Ho3+ : ((5)F4-->(5)I8) ((5)G-->(5)I8), ((8)K3--(5)I8) and ((5)F5-->(5)I8) transitions, respectively, were simultaneously observed in GCs. Compared with the glass sample, GCs have significantly intension in the green and blue upconversion fluorescence, and not significant change in the red upconversion fluorescence. Those changes are because that Ho ion in GCs locates in lower phonon energy environment than in glasses. Lower phonon energy can make the nonradiative relaxation rate reduce, which improves the green light upconversion efficiency, at the same time reduces the population of the intermediate energy level ((5)I7) of the red light radiation. The 2.9 microm mid-infrared light was observed in GC sample, but not in glass precursor excited by 980 nm laser diode.
ABSTRACT
The microstructure and spectral properties of Er3+ doped transparent oxyfluoride glass ceramics with high fluorine content were reported. Two samples with the same initial contents (50SiO2-45PbF2-5PbO-1ErF3) were prepared under the different preparation parameters. The final fluorine contents were detected by a fluoride ion selective electrode. The results shows that the final fluorine contents increase by covering crucibles with corundum lid during melt. The samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), absorption spectra and upconversion luminescence spectra. The results show that PbF2 crystals were precipitated in the sample with high fluorine content before heat treatment. And the PbF2 crystals precipitated inside the glass matrix are spherical with diameters of approximately 10-15 nm in size from the high resolution TEM micrograph. The absorption spectra, J-O parameters and the upconversion spectra show that the Er3+ ions were located in crystalline and vitreous mixed states. It is different from the sample with low fluorine content which is completely amorphous. After heat treatment, Er3+ ions that remain in the glassy phase entered into fluoride nanocrystals in the sample with high fluorine content. The fluorine environment decreases non-radiative transfer which eases the upconversion processes. Hence, the upconversion luminescence intensity of Er3+ ions in the high fluorine content sample after heat treatment is much stronger than that in the precursor sample.
ABSTRACT
OBJECTIVE: To investigate the effects of manipulative reduction on pain and clinical curative effect in patients with lumbar intervertebral disc herniation. METHODS: Eleven thousands one hundred and twenty-eight patients with lumbar intervertebral disc herniation from our hospital were enrolled from November 1986 to June 2007. They were randomly divided into control group and treatment group. Patients of the control group received lumbar traction and various physiotherapies. Patients of the treatment group received manipulative reduction, besides the treatment in the control group. The treatment was performed once a day,ten times as a course. Curative effects were assessed three courses later. Pain was evaluated by visual analogue scale before and after the treatment. RESULTS: No significant difference in the score of visual analogue scale was found before the treatment in the two groups (P > 0.05). As compared with the score before treatment,it was decreased by 4.73 points after treatment in the control group, and decreased by 6.37 points in the treatment group. The decrease was more significant in the treatment group than the control group (P < 0.01). The healing rate was 47.28% and total effective rate was 96.37% in the control group; The healing rate was 73.44% and total effective rate was 98.61% in the treatment group (P < 0.01). CONCLUSION: Manipulative reduction for lumbar intervertebral disc herniation can remarkably relieve lumbar pain and improve clinical curative effect.
Subject(s)
Intervertebral Disc Displacement/therapy , Lumbar Vertebrae , Manipulation, Spinal/methods , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Pain MeasurementABSTRACT
Er(3+)-Doped Germanium Bismuthate Glass was fabricated and characterized. The absorption spectrum and up-conversion spectrum of glass were studied. The Judd-Oflet intensity parameters omega(t) (t = 2, 4, 6), determined based on Judd-Ofelt theory, were found to be omega2 = 3.35 x 10(-20) cm2, omega4 = 1.34 x 10(-20) cm2, omega6 = 0.67 x 10(-20) cm2. Frequency up-conversion of Er(3+)-doped germanium bismuthate glass has been investigated. The up-conversion mechanisms are discussed under 808 nm and 980 nm excitation. Stimulated emission cross-section of 4I(13/2) --> 4I(15/2) transition was calculated by McCumber theory. Compared to other host glasses, the emission property of Er(3+)-doped germanium bismuthate glasses has advantage over those of silicate, phosphate and germinate glasses. Er(3+)-doped germanium bismuth glasses are promising upconversion optical and optic-communication materials.
ABSTRACT
In the present the authors are trying to work out how the quantum efficiency depends on the nanocrystalline size. Cubic nanocrystalline Y2O3 : Eu3+ samples were prepared by chemical self-combustion. The bulk Y2O3 : Eu3+ was obtained by annealing the nanocrystalline at 1 000 degrees C for 2 h. The emission spectra, XRD and fluorescence decay showed that the emission intensities are increased and fluorescence decay becomes slow with an increase in particle diameter of the samples. Two routes were used to estimate the quantum efficiency of the 5D0 level of Eu3+ at C2 site. The quantum efficiencies of 5D0 level of Eu3+ at C2 site in the samples depend on the nanocrystalline sizes. Finally, a detailed discussion about these two approaches for estimating the quantum efficiencies was made.
ABSTRACT
The purpose of this study is to explore the clinical significance of RBC blood group serological test in nonmyeloablative allogeneic peripheral blood stem cell transplantation (NAPBSCT) of ABO group incompatibility in 4 patients with acute leukemia. ABO and MN blood group of donors and recipients were determined by hemagglutination test and Rh blood group by Diana Gel phenotype Rh card. The changes of blood group in recipients were observed and implant of donor cells was monitored by short tandem repeat-PCR method. The results showed that in 2 cases of 4 recipients the marrow cells appeared mixed chimera of donor and recipient cells, and blood group changed to donor type in 1 of the 2 cases on 100 days after transplantation. In another 2 cases, the marrow cells appeared mixed chimera without blood group chimera on 154 days after transplantation, and rejection of the transplant occurred in 1 of the 2 cases. The determination of hemagglutinin titer showed that the implant rate of donor cells was lower in the recipients with higher hemagglutinin titer and blood group chimera did not appear, conversely, the implant rate was higher in the recipients with lower titer and blood group chimera appeared early. It is concluded that examination of RBC blood group in NAPB SCT can indirectly reflect effectiveness of transplantation, contribute to decide the intensity of conditioning protocol and immunosuppressive therapy after transplantation, estimate prognosis and guide blood transfusion during transplantation.
