Oxyfluoride glasses containing Ag species and rare earth (RE) ions (Dy(3+), Sm(3+), Tb(3+)) were prepared by melt-quenching technique. The type of luminescent species of novel excitation band (230-300 nm peaked at 255 nm) and emission band (300-600 nm peaked at 350 nm) were investigated by absorption, excitation, emission spectra, as well as decay lifetime measurements and can be ascribed to isolated Ag(+) ions. Owing to energy transfer from Ag(+) to RE ions, significant enhancements of RE ions emission (76 times for Sm(3+), 41 times for Dy(3+)) were observed for non-resonant UV excitation (255 nm). Our research may extend the understanding of interactions between RE ions and Ag species.
Luminescent properties of (Cu+)2, Eu3+ single-doped and codoped sodium silicate glasses were systematically investigated by excitation spectra, emission spectra, and decay curves. Due to the efficient energy transfer from (Cu+)2 pairs to Eu3+, varied hues from green to yellowish white and eventually to orange were generated by tuning the content of Eu3+. A perfect white-light emission with CIE coordinates (X=0.336,Y=0.346) was realized in (Cu+)2, Eu3+ and Ce3+ codoped samples. Our research indicates the potential application of (Cu+)2, Eu3+ codoped sodium silicate glasses for converting phosphors for UV LED chips to generate white LEDs.
Luminescent properties of Sb(3+)/Mn(2+) co-doped borosilicate glasses containing no rare earth ions were systematically investigated through absorption, excitation, emission spectra, and decay curves. Upon 250-340 nm light excitation, the glasses exhibit broad blue emission at 400 nm (Sb(3+)) and red emission at 615 nm (Mn(2+)). The varied emitted color from blue through white and eventually to red can be obtained by properly tuning the content of Mn(2+) ions due to energy transfer from Sb(3+) to Mn(2+). Our investigation shows that Sb(3+)/Mn(2+) co-doped glasses may provide a new platform to design and fabricate luminescent materials for UV LED chips in the future.
Novel Eu3+‐doped transparent oxyfluoride glass‐ceramics containing BaLuF5 nanocrystals were successfully fabricated by melt‐quenching technique for the first time. Analyses of XRD patterns prove that the new precipitated glass‐ceramics are crystallized in cubic BaLuF5 based on isostructural BaGdF5. Intense red emissions observed in glass ceramics are attributed to the enrichment of Eu3+ ions into BaLuF5 nanocrystals. Besides, obvious stark splitting emissions, low forced electric dipole 5D0→7F2 transition, and long decay lifetimes of Eu3+ ions also evidence the partition of Eu3+ ions into BaLuF5 nanocrystals with low phonon energy. Such transparent material may find applications in photonics.
Novel Ho3+ doped highly transparent NaYbF4 glass‐ceramics were successfully fabricated by melt‐quenching technique. Their structural and luminescent properties were systemically investigated by XRD, TEM, absorption spectra, upconversion spectra, and lifetime measurements. Excited by 980‐nm laser, samples exhibit characteristic emissions of Ho3+. Impressively, the luminescent color can be tuned easily from red for precursor glass to green for glass‐ceramics. Such novel phenomenon was elaborately investigated and is owing to the reduced multiphonon nonradiative relaxation and enhanced cross‐relaxation of Ho3+ in NaYbF4 nanocrystals after crystallization. Our results indicate that NaYbF4 transparent glass‐ceramics is an excellent host for upconversion.
Objective
The aim of this review was to evaluate and summarize the results of published studies exploring the effects of expiratory muscle strength training on swallowing and cough functions in patients with neurological diseases.
Data Sources
The study used Embase, PubMed, and the Cochrane Library as data sources.
Review Methods
Randomized controlled trials or pretest/posttest studies of adults with neurological diseases were included. The data included basic population characteristics, penetration-aspiration scores, peak expiratory flow rate, cough volume acceleration, and maximum expiratory pressure.
Results
Ten studies were included in this meta-analysis. Compared with the control groups, expiratory muscle strength training in patients with neurological diseases significantly reduced the penetration-aspiration scores (risk ratio = −0.94, 95% confidence interval = 1.27 to −0.61, P < 0.01) but did not increase the voluntary cough peak expiratory flow rate (risk ratio = 0.57, 95% confidence interval = 0.62 to 1.77, P = 0.35), cough volume acceleration (risk ratio = 33.87, 95% confidence interval = 57.11 to 124.85, P = 0.47), or maximum expiratory pressure (risk ratio = 14.78, 95% confidence interval = 16.98 to 46.54, P = 0.36).
Conclusions
Expiratory muscle strength training might improve swallowing function in patients with neurological diseases. However, conclusive evidence supporting the use of this approach in isolation for improving cough function is unavailable. Additional multicenter, randomized clinical trials performed using reliable and valid cough function outcome measures are required to explore the effects of expiratory muscle strength training on cough function.
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