Formation Mechanism of Crystalline Phase during Corrosion of Aluminum Phosphate Glasses

The formation mechanism of crystalline phases within the corrosion layer of glasses has attracted considerable attention, but research on the microscopic chemical process of their formation has rarely been studied. This study focuses on investigating potassium aluminum phosphate glass with a nominal molar composition of 41.6K2O–16.7Al2O3–41.7P2O5. Liquid- and solid-state nuclear magnetic resonance (NMR) techniques are employed to investigate the evolution of the aluminum species and phosphorus units of the corroded glasses, leachates, and sediments derived from immersing the glass for various durations. Our findings provide compelling evidence that the formation of the crystalline phases during the phosphate glass immersion process is a result of leached glass elements saturating in the solution and subsequently precipitation onto the glass surface. Furthermore, we have identified two distinct dissolution modes in this process, which include the overall dissolution of large molecular units presented in the initial stage and the continuous dissolution of small molecular units that persists throughout the entire corrosion process. The coexistence of these two dissolution modes leads to the formation of crystalline phases on the glass surface even before both the glass and the solution have fully reached dissolution saturation. This study sheds light on the glass corrosion mechanism at the molecular level, providing new insight into comprehending the corrosion process of glass

Supplementary document for Er-doped Silicate Fiber Amplifiers in the L band with Flat Gian and High Gain per Unit length - 6784838.pdf

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Remission for Loss of Odontogenic Potential in a New Micromilieu <i>In Vitro</i>

<div><p>During embryonic organogenesis, the odontogenic potential resides in dental mesenchyme from the bud stage until birth. Mouse dental mesenchymal cells (mDMCs) isolated from the inductive dental mesenchyme of developing molars are frequently used in the context of tooth development and regeneration. We wondered if and how the odontogenic potential could be retained when mDMCs were cultured <i>in vitro</i>. In the present study, we undertook to test the odontogenic potential of cultured mDMCs and attempted to maintain the potential during culturing. We found that cultured mDMCs could retain the odontogenic potential for 24 h with a ratio of 60% for tooth formation, but mDMCs were incapable of supporting tooth formation after more than 24 h in culture. This loss of odontogenic potential was accompanied by widespread transcriptomic alteration and, specifically, the downregulation of some dental mesenchyme-specific genes, such as <i>Pax9</i>, <i>Msx1</i>, and <i>Pdgfrα</i>. To prolong the odontogenic potential of mDMCs <i>in vitro</i>, we then cultured mDMCs in a serum-free medium with Knockout Serum Replacement (KSR) and growth factors (fibroblastic growth factor 2 and epidermal growth factor). In this new micromilieu, mDMCs could maintain the odontogenic potential for 48 h with tooth formation ratio of 50%. Moreover, mDMCs cultured in KSR-supplemented medium gave rise to tooth-like structures when recombined with non-dental second-arch epithelium. Among the supplements, KSR is essential for the survival and adhesion of mDMCs, and both Egf and Fgf2 induced the expression of certain dental mesenchyme-related genes. Taken together, our results demonstrated that the transcriptomic changes responded to the alteration of odontogenic potential in cultured mDMCs and a new micromilieu partly retained this potential <i>in vitro</i>, providing insight into the long-term maintenance of odontogenic potential in mDMCs.</p></div

KSR, Fgf2 and Egf facilitate the maintenance of odontogenic potential in cultured mDMCs.

<p><b>(A)</b> The relational network was constructed based on the strength of correlation between pairs of samples, showing the relationship of mDMCs to normal neural crest cell types. <b>(B)</b> mDMCs proliferated at a significantly higher rate in KSR-supplemented medium (M-KSR) than FBS-supplemented medium (M-FBS). <b>(C)</b> The mRNA levels of some dental mesenchyme-related genes in mDMCs cultured in medium with KSR. <b>(D)</b> Immunofluorescence analysis of Msx1, Pax9, and Pdgfrα in mDMCs cultured in medium with KSR or FBS. <b>(E)</b> Recombinants with mDMCs cultured for 24 h and 48h in KSR-supplemented medium developed into teeth after subrenal culture for 3 weeks. R, ratio of tooth formation. <b>(F)</b> Recombinants of epithelium from E10.5 mouse second-arch (mse) and cultured mDMCs developed into tooth-like structures. *<i>p</i> < 0.05 compared with the freshly isolated cells. Scale bar: D = 100 μm; E, F = 500 μm.</p

Primers for quantitative real-time PCR.

<p>Primers for quantitative real-time PCR.</p

Design of the study.

<p>Dental mesenchyme tissues from embryonic day 14.5 (E14.5) mice were digested with trypsin. Freshly isolated mouse dental mesenchymal cells (mDMCs) were divided into three groups: One group was recombined with embryonic dental epithelial and cultured in kidney; the second was submitted for RNA-seq; the third was cultured <i>in vitro</i> and harvested at indicated time points.</p

Impaired odontogenic potential in cultured mDMCs.

<p><b>(A)</b> mDMCs possess a fibroblast-like or elliptic morphology. Cell density increased significantly and the morphological alteration was visible from 24 h to 96 h. <b>(B)</b> Cells continued to proliferate in culture and cell quantity doubled in 48 h. <b>(C)</b> Recombinants with freshly isolated mDMCs and cells cultured for 24 h formed tooth after subrenal culture, but recombinants with cells cultured for 48 h formed cysts. Recombinants with E14.5 dental mesenchyme (Tis) were used as positive control. H&E staining showed the presence of tooth structure or eosinophilic amorphous matrix. D, dentin; PD, predentin; DP, dental pulp; OD, odontoblast. Scale bar: A, B = 50 μm; C = 500 μm.</p

Phenotypic alteration of cultured mDMCs.

<p><b>(A)</b> Heat map showed the decreased expression of dental mesenchyme-related genes in cultured mDMCs. <b>(B)</b> The mRNA levels of some dental mesenchyme-related genes. <b>(C)</b> Decreased expression of Msx1, Pax9, P75, and Pdgfrα in cultured mDMCs was examined by immunofluorescence assays. *<i>p</i> < 0.05 compared with the D0 cells. Scale bar: 100 μm.</p

The effects of KSR, Fgf2, and Egf on cultured mDMCs.

<p><b>(A)</b> Images of cells cultured in the medium with Egf/Fgf2, KSR/Egf, KSR/Fgf2, and KSR/Egf/Fgf2. Scale bar: 50 μm. (B) The mRNA levels of some dental mesenchyme-related genes in freshly isolated (D0) mDMCs and mDMCs cultured in KSR-, KSR/Fgf2-, KSR/Egf-, and KSR/Egf/Fgf2-supplemented medium. *<i>p</i> < 0.05 compared with the D0 cells.</p

Global transcriptome profiles of mDMCs.

<p><b>(A)</b> Hierarchical clustering analysis of dental mesenchymal tissue or cell samples. Tis, dental mesenchymal tissues. <b>(B)</b> Principal components analysis (PCA) showed the distances between various cell populations. Variation between two adjacent cell populations was reduced with time. <b>(C)</b> The number of differentially expressed genes between every two cell populations was listed. The red bracket indicates the number of upregulated genes and the blue indicates the downregulated genes. <b>(D)</b> Differentially expressed genes were divided into eight clusters according to their temporal patterns. Functional annotation analysis of genes in each cluster was performed, and the biological processes were reconstructed. The red bracket indicates processes involving the upregulated genes in the given time interval and the blue bracket indicates those involving the downregulated genes. * indicated the biological processes associated with tooth development.</p