[en] A series of new glasses of 70TeO₂-(20-x) ZnO-xWO₃-5La₂O₃-2.5K₂O-2.5Na₂O (mol %) doped with Yb³⁺ is presented. Thermal stability and spectroscopic properties of Yb³⁺ ions have been measured. It found that 70TeO₂-15WO₃-5ZnO-5La₂O₃-2.5K₂O-2.5Na₂O composition glass had better thermal stability ((T_x-T_g)>160 deg. C) than 75TeO₂-20ZnO-5Na₂O glass, high-stimulated emission cross-section of 1.32 pm² for the ²F_5/2→²F_7/2 transition and existed measured fluorescence lifetime of 0.93 ms and the broad fluorescence effective linewidth of 74.5 nm. Evaluated from the good potential laser parameters, this system glass is promising for miniature solid fiber lasers or high-peak power and high-average power lasers, also for wave-guides or tunable lasers

[en] Er³⁺-doped heavy metal oxyfluoride germanate glass suitable for developing potential optical amplifiers and upconversion lasers has been fabricated and characterized. Under 975 nm excitation, intense and broad 1533 nm infrared fluorescence and visible upconversion fluorescence were observed. For 1533 nm emission band, the full width at half maximum (FWHM) is 57 nm, the fluorescence lifetime is 5.7 ms, and the quantum efficiency is ∼100%. Efficient 529, 551, and 657 nm upconversion emissions correspond to the transitions ²H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2, and ⁴F_9/2→⁴I_15/2, respectively. Raman spectrum indicates the important role of fluoride ions in the formation of glass network. The dependence of upconversion intensities on excitation power involves two-photon absorption processes for the three emission bands. The possible upconversion mechanisms are discussed based on the energy matching conditions and the quadratic dependence on excitation power

[en] The upconversion properties and mechanism of Er³⁺ ions have been studied for lead oxyfluorosilicate glasses containing Er₂O₃ concentrations from 0.2 to 2 mol%. Under 975 nm excitation, four emission bands centered at 411, 525, 543, and 655 nm corresponding to the ²H_9/2→⁴I_15/2, ²H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2, and ⁴F_9/2→⁴I_15/2 transitions of Er³⁺ ions, respectively, were simultaneously observed at room temperature. The bright green and red emissions are due to a two-photon upconversion process while the weak blue emission is determined by a three-photon upconversion process. Raman spectrum indicates that fluoride ions in the formation of glass network have important influence on upconversion luminescence of Er³⁺ in lead oxyfluorosilicate glasses. The intense upconversion luminescence of Er³⁺-doped lead oxyfluorosilicate glasses may be a potentially useful material for developing upconversion optical devices

[en] A series of new glasses of 70TeO₂-(20-x) ZnO-xGeO₂-5La₂O₃-2.5K₂O-2.5Na₂O (mol%) doped with Yb³⁺ is presented. Thermal analysis, spectra and laser properties of Yb³⁺ ions have been measured. It is found that 70TeO₂-20GeO₂-5La₂O₃-2.5K₂O-2.5Na₂O composition glass had better thermal stability than 75TeO₂-20ZnO-5Na₂O glass, higher stimulated emission cross-section of 1.23 pm² for the ²F_5/2→²F_7/2 transition close to PN glass, lower minimum pump intensity of 0.98 KW/cm², long fluorescence lifetime of 0.92 ms and the broad fluorescence effective line width of 77 nm. Evaluated from the good potential laser parameters, this system glass is a promising host of miniature solid lasers such as short pulse generation in diode pumped lasers, short pulse generation tunable lasers, high-peak power and high-average power lasers, etc

[en] The green and red upconversion luminescence of Er³⁺ in lead chloride tellurite glasses excited at 980 nm is investigated. Three intense emission bands centered at 530, 545, and 658 nm corresponding to the transitions ⁴S_3/2→⁴I_15/2, ²H_11/2→⁴I_15/2 and ⁴F_9/2→⁴I_15/2, respectively, were simultaneously observed at room temperature. With increasing PbCl₂ content, the intensity of green (530 nm) emissions increase slightly, while the green (545 nm) and red (658 nm) emissions increase significantly. The results indicate that PbCl₂ has more influence on the green (545 nm) and red (658 nm) emissions than the green (530 nm) emission. The dependence of upconversion intensities on excitation power and possible upconversion mechanisms are discussed and evaluated

[en] The effect of Al(PO₃)₃ content on physical, chemical and optical properties of fluorophosphate glasses for 2 μm application, such as thermal stability, chemical durability, surface hardness, absorption spectra and emission spectra, is investigated. With the increment of Al(PO₃)₃ content, the thermal stability characterized by the gap of T_g and T_x increases first and then decreases, and reaches the maximum level containing 5 mol% Al(PO₃)₃ content. The density and chemical durability decrease monotonously with the introduction of Al(PO₃)₃ content increasing, while the refractive index and surface hardness increase. Above properties of fluorophosphate glasses are also compared with fluoride glasses and phosphate glasses. The Judd-Ofelt parameters, absorption and emission cross sections are discussed based on the absorption spectra of Tm-doped glasses. The emission spectra are also measured and the 1.8 μm fluorescence of the sample is obvious indicating that it is suitable to 2 μm application

[en] Highlights: • Morphine tolerance increases TCF7L2 expression in mice spinal cord. • Chronic morphine treatment upregulates TCF7L2 expression and inflammation. • Chronic morphine treatment activates TLR4/NF-κB/NLRP3 signaling pathway. • TCF7L2 regulates chronic morphine-induced microglia activation. • TCF7L2 regulates TLR4 expression via transcriptional activation. Morphine is an opioid agonist and a nonselective mu, kappa and delta receptor agonist. It is a commonly used analgesic drug for the treatment of acute and chronic pain as well as cancer pain. Morphine is particularly important to address the problem of morphine tolerance. Tcf7l2, known as a risk gene for schizophrenia and autism, encodes a member of the LEF1/TCF transcription factor family. TCF7L2 is an important transcription factor that is upregulated in neuropathic pain models. However, the relationship between TCF7L2 and morphine tolerance has not been reported. In this study, we found that morphine tolerance led to the upregulation of TCF7L2 in the spinal cord, and also led to the upregulation of TCF7L2 expression in glial cells, which promoted inflammation related signal, and activated TLR4 / NF-κB/NLRP3 pathway. In addition, TCF7L2 regulated microglial cell activation induced by chronic morphine treatment. Mechanically, we found that TCF7L2 transcriptionally regulated TLR4 expression, and the depletion of TCF7L2 alleviated morphine tolerance induced by chronic morphine treatment, and further alleviated pain hypersensitivity induced by chronic morphine treatment. We therefore suggested that TCF7L2 regulates the activation of TLR4/ NF-κB/NLRP3 pathway in microglia, and is involved in the formation of morphine tolerance. Our results provide a new idea for the regulation mechanism of morphine tolerance.

[en] Effect of the substitutions of chloride for fluoride on the chemical and physical properties and the crystallization behavior in heavy metal fluoride glasses has been investigated. The characteristic temperature of the glass does not changed obviously when the fluoride was taken place by chloride. Compared with samples of being free of ErF₃, the doping samples are more inclined to be surface crystallization. Optical basicity in the glass system increases with increasing the negative charge provided by the chloride atoms and the absorption peak red shifted is observed in absorption spectra. XRD measurements show that not a single crystalline phase appears in the heated glass samples, which indicate the substitutions of chloride for fluoride with a variety of crystalline precipitation trends

[en] Tellurite glass is proposed as a host for broadband erbium-doped fiber amplifiers because of their excellent optical and chemical properties. A single-mode Er³⁺-doped tellurite glass fiber with D-shape cladding was fabricated in this work. The characterization of amplified spontaneous emission (ASE) from this newly fabricated Er³⁺-doped tellurite fibers are exhibited. When pumped at 980 nm, a very broad erbium ASE nearly 150 nm around 1.53 μm is observed. The changes in ASE with regard to fiber lengths and pumping power were measured and discussed. The output of 2 mW from Er³⁺-doped tellurite fiber ASE source was obtained under the pump power of 660 mW. The broad 1.53 μm emission of Er³⁺ in tellurite glass fiber can be used as host material for potential broadband optical amplifier and tunable fiber lasers

[en] The effects of F^- ions in zinc-tungsten-tellurite glass system on the spectral and potential laser properties of the Yb³⁺ are investigated. The absorption spectra, lifetimes, the emission cross-sections and the minimum pump intensities of the glass system with and without F^- ions have been measured and calculated, respectively. The results show that the fluorescence lifetime and the minimum pump intensity of Yb³⁺ ions increase evidently which indicate that zinc-tungsten-oxyfluoride tellurite glass is a promising laser host matrix for high power generation. FT-IR spectra were used to analyze the effect of F^- ions on OH^- groups in this glass system. Analysis demonstrates that addition of fluoride in this tellurite glass removes the OH^- groups and results in improvement of fluorescence lifetime of Yb³⁺