Top-Seeded Solution Crystal Growth and Functional Properties of Polar LiFeP₂O₇

Large single crystals of LiFeP₂O₇, a multifunctional polar material, were successfully grown by using a top-seeded solution growth (tssg) technique. The morphologies of the single crystals with different rotation speeds are described. Functional properties such as second-harmonic generation (SHG), piezoelectricity, pyroelectricity, and ferroelectricity were measured. LiFeP₂O₇ is SHG active, with an SHG efficiency of approximately 200 × α-SiO₂ using 1064 nm radiation. The material is piezoelectric, with a <i>d</i>₂₂ value of 1.2 pC/N, and pyroelectric, with pyroelectric coefficients of 9.25 μC/m²K (1 kHz) and 10.6 μC/m²K (50 Hz) at 60 °C. Although polar, LiFeP₂O₇ is not ferroelectric; that is, the polarization is not “switchable”. Optical spectra indicate that the absorption edge is approximately 480 nm, with transmission up to 4.3 μm

Large Birefringent Materials, Na₆Te₄W₆O₂₉ and Na₂TeW₂O₉: Synthesis, Structure, Crystal Growth, and Characterization

A new d⁰ transition metal tellurite, Na₆Te₄W₆O₂₉, was synthesized by solid-state methods. The material crystallizes in monoclinic space group <i>P</i>2₁/<i>c</i> (No. 14) with the following values: <i>a</i> = 7.3297(3) Å, <i>b</i> = 21.9057(9) Å, <i>c</i> = 10.2871(3) Å, β = 133.490(2)°, and <i>Z</i> = 2. Additionally, large crystals of Na₆Te₄W₆O₂₉ (13 mm × 11 mm × 10 mm) and Na₂TeW₂O₉ (23 mm × 5 mm × 3 mm) were grown by the top seeded solution growth method. In addition to the crystal growth, refractive indices were measured, and the Sellmeier equations were fitted by using the minimum deviation technique. Interestingly, the two reported compounds exhibit relatively large birefringences: Δ<i>n</i>₃ = <i>n</i>_<i>z</i> – <i>n</i>_<i>x</i> = 0.0828–0.1248 from 1062.6 to 450.2 nm for Na₆Te₄W₆O₂₉, and Δ<i>n</i>₃ = <i>n</i>_<i>z</i> <i>– n</i>_<i>x</i> = 0.1471–0.2069 from 1062.6 to 450.2 nm for Na₂TeW₂O₉. The results indicate that Na₆Te₄W₆O₂₉ and Na₂TeW₂O₉ may have uses in applications involving birefrigent materials

Morphological response of MSCs to flow with aligned nanofibers at multiple angles.

<p>A: Cytoskeletal and nuclei morphology of rMSCs cultured in microfluidic-nanofiber device for 24 h. The flow direction coinciding with the fiber direction was defined as 0°. Green = f-actin. Blue = nuclei. Scale bar: 50 µm. B: Variation of shape index (SI) under each condition. C: Variation of nuclear aspect ratio (NAR) under each condition. Data are presented as mean ± SD of n = 30 cell bodies and nuclei measured for three different batches of devices for each condition. *<i>p</i><0.01 vs. 0°. ^#<i>p</i><0.01 vs. static.</p

Sequences of primers used in real-time RT-PCR.

<p>Sequences of primers used in real-time RT-PCR.</p

ROCK is involved in fibrochondrogenesis of MSCs.

<p>A: Immunofluorescence staining for f-acin (green) and DAPI (blue) after MSCs treated (ii) or untreated (i) with the ROCK inhibitor Y27632 under perpendicular flow stimulus for 6 h. Scale bar: 20 µm. B–F: Fibrochondrogenesis-related gene expression of Sox9 (B), Runx2 (C), collagen I (D), collagen II (E), and aggrecan (F) was analyzed after 4 weeks of differentiation under perpendicular flow with a peak shear stress of 1 dyne/cm². Data were presented as mean ± SEM. *<i>p</i><0.01, cell treated with Y27632 vs. untreated with Y27632.^†<i>p</i><0.05 perpendicular flow vs. static for Y27632-untreated group. ^#<i>p</i><0.05, perpendicular flow vs. static for Y27632-treated group.</p

The expression of fibrochondrogenic markers after 4 weeks of induced differentiation of MSCs under flow stimulus at different angles with aligned nanofibers.

<p>A: Immunofluorescence staining for collagen I (red) and DAPI (blue). B: Immunofluorescence staining for collagen II (green) and DAPI (blue). C: Alcian blue staining for proteoglycans. Scale bar: 50 µm.</p

Fibrochondrogenesis-related gene expression in MSCs.

<p>Sox9, Runx2, collagen I, collagen II, and aggrecan gene expression was analyzed after 4 weeks of differentiation under perpendicular flow (90°) or parallel flow (0°) with a shear stress of 1 dyne/cm². Data are presented as mean ± SEM. *<i>p</i><0.05, flow vs. static condition. ^#<i>p</i><0.05, perpendicular flow vs. parallel flow.</p

YAP/TAZ is involved in fibrochondrogenesis of MSCs.

<p>A: MSCs were transfected with siYAP and siTAZ, and efficient knockdown of the endogenous proteins were analyzed by Western blot analysis. B–F: Fibrochondrogenesis-related gene expression of Sox9 (B), Runx2 (C), collagen I (D), collagen II (E), and aggrecan (F) was analyzed after 4 weeks of differentiation under perpendicular flow with a peak shear stress of 1 dyne/cm². Data were presented as mean ± SEM. *<i>p</i><0.01, siYAP/TAZ vs. sicontrol. ^†<i>p</i><0.05 perpendicular flow vs. static for sicontrol group. ^#<i>p</i><0.05, perpendicular flow vs. static for siYAP/TAZ group.</p

Characterization of PLGA meshes with aligned electrospun nanofibers.

<p>A: SEM image of PLGA nanofibers. Scale bar: 10 µm. B and C: The microscope images of PLGA nanofibers embedded in the perfusion microchambers of the microfluidic device. Scale bar: 50 µm. D: Graph depicting the percentage of aligned fibers in the meshes. Data are presented as mean ± SD.</p

Characterization of MSCs.

<p>A: Flow cytometry analysis showed that the cells were positive for i) CD90 (99.18%±1.02%) and iii) CD29 (99.17%±1.07%), negative for the hematopoietic marker ii) CD45 (0.76%±0.25%). B: Cells at passage 2 exhibited spindle-shaped morphology and homogeneous phenotype. C: Oil red O staining showed intracellular lipid droplets after induction of adipogenic differentiation. D: Alkaline phosphatase was detected in the cytoplasm after induction of osteogenic differentiation. Scale bar: 100 µm.</p