Relationship Between Atypical Symptoms of Degenerative Cervical Myelopathy and Segments of Spinal Cord Compression: Retrospective Observational Study.

BACKGROUND: Patients with degenerative cervical myelopathy (DCM) often present with atypical symptoms such as vertigo, headache, palpitations, tinnitus, blurred vision, memory loss, and abdominal discomfort. This study aims to investigate the relationship between atypical symptoms of DCM and the segments of spinal cord compression. METHODS: The 166 DCM patients with atypical symptoms admitted to our institution from 2019 to 2020 were divided into vertigo, headache, blurred vision, tinnitus, and palpitations groups according to their atypical symptoms, while the typical group was 214 DCM patients with typical symptoms only. Differences in segments of compression were compared among the groups. Results of more than 1-year of follow-up were further summarized for nonsurgical and surgical treatment of DCM patients with atypical symptoms. RESULTS: The incidence of vertigo, headache, blurred vision, tinnitus, and palpitations of all DCM patients was 37%, 18%, 15%, 11%, and 11%, respectively. Compared with the typical group, patients in the blurred vision and tinnitus group were older (P < 0.05) and the incidence of spinal cord compression at C3-5 in the vertigo group, C4-5 in the headache group, and C6-7 in the palpitation group was higher (P < 0.05). The scores of vertigo, headache, and palpitations decreased after surgical decompression (P < 0.05), whereas only vertigo and headache scores decreased after nonsurgical treatment (P < 0.05). CONCLUSIONS: Atypical symptoms were common in patients with DCM, and the segments of spinal cord compression might be associated with specific atypical symptoms. Surgical treatment is effective in relieving some of the atypical symptoms.

Site-related broadband sensitization in La3Ga5.5Nb0.5O14: Cr3+, Ln3+(Ln = Yb, Er) phosphors.

Yb3+ 1000 nm and Er3+ 1536 nm emission can be efficiently sensitized by broadband absorption of Cr3+ in almost the whole visible region in La3Ga5.5Nb0.5O14(LGNO): Cr3+, Ln3+ (Ln = Yb, Er) phosphor. Between the two kinds of Cr3+ sites, tetrahedral Cr(II) mainly behaves as the broadband sensitizer for Er3+ or Yb3+. Meanwhile octahedral Cr(I) may energy transfer (ET) to Cr(II), thereby influences the luminescence decay of Cr(II) as increasing Er3+ or Yb3+ content. This kind of site-related broadband sensitization may propose a strategy of designing tunable ET process between transition metal ions and rare earth ions.

Synthesis and luminescence properties of CaSnO3 :Bi3+ blue phosphor and the emission improvement by Li+ ion.

CaSnO3 :Bi3+ blue-emitting phosphor was synthesized using a high-temperature solid-state reaction method in air. The crystal structures and luminescence properties were investigated. A broad emission band peaking at ~448 nm upon excitation at 262 and 308 nm was observed in the range 330-680 nm at room temperature due to 3 P1  â†’ 1 S0 transition of the Bi3+ ion. The chromaticity coordinate was (0.1786, 0.1665). The optimal Bi3+ ion concentration was ~0.6 mol% in CaSnO3 :Bi3+ phosphor. The emission spectrum of CaSnO3 :Bi3+ phosphor showed a blue-shift with increasing temperature from 50 to 300 K due to the influence of temperature on the electron transition of the Bi3+ ion. The emission intensity of CaSnO3 :Bi3+ phosphor may be increased ~1.45 times by co-doping Li+ ions as a charge compensator and fluxing agent. The luminescence mechanism is explained by a configurational coordinate diagram of Bi3+ ion in CaSnO3 :Bi3+ phosphor.

Luminescence Properties and Synthesis of SrMgAl10O17:Mn4+ Red Phosphor for White Light-Emitting Diodes.

A series of Mn4+ doped SrMgAl10O17 phosphors are synthesized by a conventional solid-state reaction method in air, and their crystal structure, morphology, and fluorescence properties are investigated. The luminescence properties show clearly that SrMgAl10O17:Mn4+ phosphor can be excited by UV (200-380 nm), near UV (380-420 nm), and blue (420-480 nm) bands of LEDs chip, and emits red light in the range of 600 nm to 750 nm with satisfying CIE chromaticity coordinates (0.7207, 0.2793). The optimal doping concentration of Mn4+ ion is ~1 mol%, and its lifetime is ~1.15 ms. The possible luminous mechanism of Mn4+ ion is discussed by Tanabe-Sugano diagram. These experiment results indicate that Mn4+ doped SrMgAl10O17 phosphors can be a potential application as a red-emitting phosphor candidate in white LEDs.

Synthesis and Optical Properties of Eu3+ Doped NaYF4 and KYF4 Micro/Nanocrystals.

Through a hydrothermal method, 1 mol% Eu3+ doped NaYF4 and KYF4 micro/nanocrystals have been synthesized. The materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM) images, room temperature photoluminescence (PL) excitation and emission spectra, and luminescent dynamic decay curves. The XRD analysis suggested the crystalline structures of the obtained samples. The FE-SEM images indicated the morphology and size of the obtained samples. The PL spectra illustrate the optical properties of Eu3+ in the two samples. Since it is sensitive to the local environment of the ion, the Eu3+ presents different optical properties in the NaYF4 and KYF4 materials.

Synthesis, energy transfer and tunable emission properties of SrSb2O6:Eu(3+), Bi(3+) phosphor.

Host SrSb2O6, SrSb2O6:Bi(3+), SrSb2O6:Eu(3+), and SrSb2O6:Eu(3+), Bi(3+) phosphors are synthesized by solid state reaction method in air. Host SrSb2O6 with excitation 254nm shows weak green-yellow emission in the range of 320-780nm due to Sb(5+)→O(2-) transition. SrSb2O6:Bi(3+) phosphor with excitation 365nm emits green light within the range 400-650nm owing to the (3)P1→(1)S0 transition of Bi(3+) ion. SrSb2O6:Eu(3+) phosphor with excitation 254nm exhibits a systematically varied hue from green to orange-red light by increasing Eu(3+) concentration from 0 to 7mol%, and that with excitation 394nm only shows orange-red light. The optimal Eu(3+) concentration is ~4mol% in SrSb2O6:Eu(3+) phosphor. SrSb2O6:Eu(3+), Bi(3+) phosphor with excitation 254 and 394nm emits orange-red light. Emission intensity of SrSb2O6:Eu(3+) phosphor may be enhanced >2 times by co-doping Bi(3+) ion because of the fluxing agent and energy transfer roles of Bi(3+) ion in SrSb2O6:Eu(3+), Bi(3+) phosphor. The luminous mechanism of SrSb2O6:Eu(3+), Bi(3+) phosphor is analyzed and explained by the simplified energy level diagrams of Sb2O6(2-) group, Bi(3+) and Eu(3+) ions, and energy transfer processes between them.

Tunable emission, energy transfer and charge compensation in SrMoO4:Sm(3+),Tb(3+),Na(+) phosphor.

A series of SrMoO4:Sm(3+),Tb(3+),Na(+) phosphors was synthesized using a high-temperature solid-state reaction method in air. On excitation at 290 nm, SrMoO4:Sm(3+),Tb(3+) phosphor emitted light that varied systematically from green to reddish-orange on changing the Sm(3+) and Tb(3+) ion concentrations. The emission intensities of SrMoO4:Sm(3+) and SrMoO4:Sm(3+),Tb(3+) phosphors were increased two to four times due to charge compensation when Na(+) was added as a charge compensator. The luminescence mechanism and energy transfer could be explained using energy-level diagrams of the MoO4(2-) group, Sm(3+) and Tb(3+) ions. SrMoO4:Sm(3+),Tb(3+),Na(+) could be used as reddish-orange phosphor in white light-emitting diodes (LEDs) based on an ~ 405 nm near-UV LED chip. This research is helpful in adjusting and improving the luminescence properties of other phosphors.

Tunable emission, energy transfer and charge compensation in Sr3(VO4)2:Sm(3+),P(5+),Na(+) phosphor.

A series of Sr3(VO4)2:Sm(3+),P(5+),Na(+) phosphors are synthesized by using solid-state reaction method in air. The strongest emission band peaking at ∼600 nm is assigned to the (4)G5/2→(6)H7/2 transition of Sm(3+) ion, and the strong excitation peak at ∼402 nm due to (6)H5/2→(4)F7/2 transition indicates that these phosphors can be excited by near ultraviolet light emitting diode chip. Energy transfer (ET) between VO4(3-) group and Sm(3+) ion can be observed. Sr3(VO4)2:Sm(3+) phosphor with excitation 320 nm exhibits a systematically varied hues from green to yellow by changing Sm(3+) ion concentration from 0 to 6 mol%. The luminous mechanism of Sr3(VO4)2:Sm(3+) phosphor is explained by using the energy level diagrams of VO4(3-) group and Sm(3+) ion. The luminescence properties of Sr3(VO4)2:Sm(3+) phosphor can be improved and tuned by codoping the P(5+) and Na(+) ions due to ET and charge compensation. Lifetimes of Sr2.925Sm0.05(VO4)2, Sr2.925Sm0.05(V0.9P0.1O4)2, and Sr2.9Na0.05Sm0.05(V0.9P0.1O4)2 phosphors are 1.208, 1.219, and 0.796 ms, respectively. The experiment results are helpful to adjust the luminescence properties of Sm(3+)-doped other phosphors.

Energy transfer and luminescence properties of Sr[1-3(x+y)/2]Al2B2O7:xEu³âº, yBi³âº phosphor.

Sr[1-3(x+y)/2]Al2B2O7:xEu(3+), yBi(3+) (x=0-5 mol% and y=0-5 mol%) phosphors are synthesized by a solid-state reaction method in air, and their crystal structure, fluorescence lifetime, and luminescence properties are investigated. The optimal composition is determined to be (Sr0.94Eu0.03Bi0.01)Al2B2O7. The PLE band peaks within the range 200-550 nm are due to O(2-)→Eu(3+) charge transfer band, (7)F0→(5)H3, (5)D4, (5)L7, (5)L6, (5)D3, (5)D2, and (5)D1 transitions, respectively. The strongest PL band peak under excitation 394 nm light is at ∼615 nm owing to (5)D0→(7)F2 transition of Eu(3+) ion. The PL intensity of Eu(3+), Bi(3+) co-doped SrAl2B2O7 phosphor is 1.3 times that of Eu(3+) doped SrAl2B2O7 phosphor due to the energy transfer between Eu(3+) and Bi(3+) ions, which is explained by the energy level diagrams of Bi(3+) and Eu(3+) ions. The CIE chromaticity coordinates of Sr0.955Al2B2O7:0.03Eu(3+) and Sr0.94Al2B2O7:0.03Eu(3+), 0.01Bi(3+) phosphors under excitation 394 nm light are (x=0.6292, y=0.3702) and (x=0.6284, y=0.3711), respectively. These phosphors will be used as reddish orange emitting phosphor candidate for white LED with ∼394 nm near ultraviolet LED chip.

Tunable photoluminescence properties of Sr(1-y)CayMoO4:Sm3+ phosphors (0 ≤ y < 1).

A series of Sr(1-x-y)CayMoO4:xSm(3+) (0 ≤ x ≤ 7 mol% and 0 ≤ y < 1) phosphors was synthesized by a conventional solid-state reaction method in air, and their structural and spectroscopic properties were investigated. The optimal doping concentration of Sm(3+) in SrMoO4:Sm(3+) phosphor is 5 mol%. Under excitation with 275 nm, in Sr(1-x-y)CayMoO4:xSm(3+) (0 ≤ x ≤ 7 mol% and 0 ≤ y < 1) phosphors, the emission band of the host was found to overlap with the excitation bands peaking at ~ 500 nm of Sm(3+) ion, and the energy transfer from MoO4 (2-) group to Sm(3+) ion can also be observed. The International Commission on Illumination (CIE) chromaticity coordinates of Sr(0.95-y)CayMoO4:0.05Sm(3+) phosphors with excitation 275 nm varied systematically from an orange (0.4961, 0.3761) (y = 0) to a white color (0.33, 0.3442) (y = 0.95) with increasing calcium oxide (CaO) concentration. However, Sr(0.95-y)CayMoO4:0.05Sm(3+) phosphors with excitation at 404 nm only showed red emission and the energy transfer between MoO4(2-) group to Sm(3+) ion was not observed. The complex mechanisms of luminescence and energy transfer are discussed by energy level diagrams of MoO4(2-) group and Sm(3+) ion.

Luminescence properties of red-emission Mg4 Nb2 O9:Eu3+ phosphor.

Red-emitting Mg4 Nb2 O9 :Eu(3+) phosphor is synthesized via a solid-state reaction method in air, and its crystal structure and luminescence are investigated. The phosphor can be excited efficiently by ~ 395 nm light, coupled well with a ~ 395 nm near-ultraviolet chip and emits red light at ~ 613 nm with sharp spectra due to (5) D0 → (7) F2 transition of the Eu(3+) ion. Mg4 Nb2 O9 :Eu(3+) phosphor sintered at 1350 ºC shows Commission international de I'Eclairage (CIE) chromaticity coordinates of x = 0.6354, y = 0.3592, and is a potential red-emitting phosphor candidate for white light-emitting diodes (W-LEDs) under ~ 395 nm near-ultraviolet LED chip excitation.

Synthesis, phase evolution and optical properties of Tb(3+)-doped KF-YbF3 system materials.

KF-YbF3 system materials have been synthesized by a hydrothermal method without any surfactant or template. By controlling the reactant ratios of KF:Yb(3+), the hydrothermal temperature and the pH of the prepared solutions, the final products can evolve among the orthorhombic phase of YbF3, the cubic phase of KYb3F10 and the cubic phase of KYbF4. The X-ray diffraction (XRD) patterns of the samples prove the phase evolution of the final products. The morphologies of the samples were characterized using field emission scanning electron microscopy (FE-SEM) images and the evolution of the morphology is consistent with that of the crystalline phases. The optical properties of Tb(3+) in the samples were characterized by PL excitation and emission spectra, as well as luminescent decay curves.

Synthesis, optical properties, and energy transfer of Ce(3+)/Tb(3+) co-doped MyGdFx (M=Li, Na, K).

Through a solid-state reaction method, the Ce(3+)/Tb(3+) co-doped MyGdFx (M=Li, Na, K; x=3, 4, 6; y=0, 1, 3) system samples have been synthesized by controlling the annealing temperatures and the ratios of raw materials. The samples were characterized by X-ray diffraction (XRD) patterns, photoluminescence (PL) excitation and emission spectra as well as luminescent dynamic decay curves. The experimental results suggest that the LiF is more difficult to react with the prepared material compared that of NaF or KF under similar reaction conditions. The samples crystallized in different crystalline phases. The energy transfer from Ce(3+) to Tb(3+) or Ce(3+) to Gd(3+) to Tb(3+) has been observed in all the samples. The Ce(3+) and Tb(3+) present different optical properties for they are sensitive to the local environment. In addition, the deduced lifetime of Tb(3+)(5)D4→(7)F5 transition decreases in the same system samples with the annealing temperature increasing. The deduced lifetime of Tb(3+)(5)D4→(7)F5 also decreases with the increase of the KF concentration in the KF system samples.

Near-infrared emission Ba3(PO4)2:Mn5+ phosphor and potential application in vivo fluorescence imaging.

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1350 nm) is attracting attention due to negligible tissue scattering and lower tissue autofluorescence, etc. Here, Ba3(PO4)2:Mn(5+) phosphor is prepared via solid state reaction method in air, and NIR emission band peaking at ∼1191 nm in the NIR-II region is observed. According to experiment results, Ba3(PO4)2:Mn(5+) phosphor has a great potential for the study of the NIR-II fluorescence imaging in vivo.

Enhanced luminescence in SrMgAl(x)O(17±Î´):yMn4+ composite phosphors.

Red-emitting SrMgAlxO17±Î´:yMn(4+) composite phosphors (x=10-100; y=0.05-4.0 mol%) are synthesized by solid-state reaction method in air. Addition of Al2O3 leads to the formation of two concomitant phases, i.e., SrMgAl10O17 and Al2O3 phases in the composite phosphor. Red emission from Mn(4+) ions in the composite phosphors is greatly enhanced due to multiple scattering and absorption of excitation light between SrMgAl10O17 and Al2O3 phases. SrMgAlxO17±Î´:yMn(4+) composite phosphors would be a promising candidate as red phosphor in the application of a 397 nm near UV-based W-LED.

Yellow-to-orange emission from B2+-doped RF2 (R = Ca and Sr) phosphors.

RF2:Bi (R = Ca and Sr) phosphors were synthesized by solid state reaction method in air and their luminescence properties were investigated. Broad yellow-to-orange emissions peaking at ~550 nm (CaF2:Bi) and ~600 nm (SrF2:Bi) were observed under ~260 nm excitation. The emission centers inRF2:Bi (R = Ca and Sr) phosphors are Bi2+ ions, and the excitation and emission bands of RF2:Bi (R = Ca and Sr) phosphors can be attributed to 2P 1/2 → 2S 1/2 and 2P 3/2(1) → 2P 1/2 transitions of Bi2+ ions, respectively. The phosphors are promising for application in lighting due to broad yellow-to-orange emission.

Near-infrared to mid-infrared photoluminescence of Bi2O3-GeO2 binary glasses: comment.

We discuss the origin of near- to mid-infrared emissions in Bi-doped oxide glasses recently reported [Opt. Lett.37, 4260 (2012)]. Our detailed analysis indicates that the near- to mid-infrared emissions in the range of 1200-3000 nm peaking at ~2500, 2650, and 2700 nm do not result from Bi active centers in the oxide matrix but are due to the selective atmospheric absorption of thermal radiation induced by laser irradiation.

Photoluminescence of Bi(2+)-doped BaSO4 as a red phosphor for white LEDs.

Bi(2+)-doped BaSO(4) phosphor was synthesized in air via solid state reaction method. Three excitation bands and one emission band were observed at 260 nm ((2)P(1/2) → (2)S(1/2)), 452 nm ((2)P(1/2) → (2)P(3/2)(2)), 592 nm ((2)P(1/2) → (2)P(3/2)(1)), and 627 nm ((2)P(3/2)(1) → (2)P(1/2)), respectively. W-LEDs were demonstrated by using a blend composition of BaSO(4):Bi(2+) and YAG:Ce(3+) hosphors pumped with a 455 nm blue LEDs chip. The results indicate that BaSO(4):Bi(2+) phosphor is suitable as potential red phosphor for application in W-LEDs excited with blue LEDs chip.

Broadband NIR luminescence from a new bismuth doped Ba2B5O9Cl crystal: evidence for the Bi0 model.

A new type of bismuth doped Ba(2)B(5)O(9)Cl crystal is reported to exhibit broadband near infrared (NIR) photoluminescence at room temperature, which has been identified here originating from elementary bismuth atom. Rietveld refining, static and dynamic spectroscopic properties reveal two types of Bi(0) centers in the doped compound due to the successful substitution for two different nine-coordinated barium lattice sites. These centers can be created only in a reducing condition, and when treated in air and N(2)/H(2) flow in turn, they can be removed and restored reversely. As the dwelling time is prolonged in N(2)/H(2) at high temperature, conversion from Bi(2+) to Bi(0), as reflected by changes of their relative emission intensities, is witnessed in the crystal of Ba(2)B(5)O(9)Cl:Bi. The lifetime of the NIR luminescence was observed in a magnitude of ~30 µs, rather different from bismuth doped either glasses or crystals reported previously.

Superbroad near to mid infrared luminescence from closo-deltahedral Bi5(3+) cluster in Bi5(GaCl4)3.

Closo-deltahedral Bi(5)(3+) cluster in Bi(5)(GaCl(4))(3), which can be synthesized in benzene by oxidizing bismuth metal either with BiCl(3) or GaCl(3), respectively, can absorb ultraviolet, visible and infrared lights, and luminesce superbroadly in near to mid infrared (NMIR) spectral range from 1 to 3µm at room temperature. Slight geometry change of the cluster can lead to the redshift of emission peak. These observations may initialize the development of Bi-based NMIR light sources with superbroad emission spectrum, where Bi(5)(3+) or similar polycationic species act as activators. Disputable crystal structure of Bi(5)(GaCl(4))(3) was redefined by classic Rietveld refining analysis. Consistent with crystallographic data, excitation, emission, temporal decay and time-resolved infrared emission spectra all reveal only one type of luminescent centers, viz. Bi(5)(3+), in the compound. And a new absorption of Bi(5)(3+) was found at ~1100nm.