5 research outputs found

    Structured Assemblages of Single-Walled 3d Transition Metal Silicate Nanotubes as Precursors for Composition-Tailorable Catalysts

    No full text
    Copper silicate has so far been the only transition metal silicate that can be synthesized into a single-walled nanotubular structure. In addition to making single-walled copper silicate nanotubes (CuSiNT) as hollow spherical or bundle-like assemblages, herein, we developed a general method to synthesize a series of new single-walled silicate nanotubes containing other 3d transition metal elements (M = Mn, Fe, Co, Ni, and Zn). After the controllable synthesis of CuSiNT, up to 80% of Cu in the CuSiNT can be replaced with dopant metals (M) through complex-assisted ion exchange, while the original tubular structure remains intact. These metal silicate nanotubes can serve as solid precursors for design-made nanocatalysts; enhanced catalytic performance has been demonstrated using CO<sub>2</sub> hydrogenation as a model reaction

    Monodisperse Aluminosilicate Spheres with Tunable Al/Si Ratio and Hierarchical Macro-Meso-Microporous Structure

    No full text
    While tremendous success has been seen in the development of ordered mesoporous silica by soft-templated methods, synthesis of hierarchical structures with controllable multiscale pore networks has remained a challenging topic. On the other hand, introduction of heteroatoms as an effective method of chemically functionalizing silica leads to difficulties in morphological control of the product, and multistep synthesis has been necessary for functionalized silica particles with hierarchical pore structure and uniform size. The present work demonstrates that the conflict between morphological control and heteroatom incorporation can be resolved in a CTAB-stabilized toluene–water–ethanol microemulsion system. For the first time, monodisperse macro-meso-microporous aluminosilicate spheres (MASS) are synthesized in one step at room temperature. Simultaneous tuning of Al/Si ratio (0–0.35) and the hierarchical pore structure is realized by Hofmeister anion effects of the Al source itself, [Al­(OH)<sub>4</sub>]<sup>−</sup>, which change the geometry of CTAB micelles and giant vesicles. The Al is incorporated purely in a tetrahedrally coordinated status, and preliminary results from catalytic experiments show improved acidity of MASS as a catalyst support

    sj-doc-1-cnr-10.1177_10547738231194099 – Supplemental material for Implementation of Tunneled Peripherally Inserted Central Catheters Placement in Cancer Patients: A Randomized Multicenter Study

    No full text
    Supplemental material, sj-doc-1-cnr-10.1177_10547738231194099 for Implementation of Tunneled Peripherally Inserted Central Catheters Placement in Cancer Patients: A Randomized Multicenter Study by Yuan Sheng, Li-Hong Yang, Yan Wu, Wei Gao and Sheng-Yi Dongye in Clinical Nursing Research</p

    Acid-Sensitive Peptide-Conjugated Doxorubicin Mediates the Lysosomal Pathway of Apoptosis and Reverses Drug Resistance in Breast Cancer

    No full text
    The extended use of doxorubicin (DOX) could be limited because of the emergence of drug resistance associated with its treatment. To reverse the drug resistance, two thiol-modified peptide sequences HAIYPRHGGC and THRPPMW­SPVWPGGC were, respectively, conjugated to DOXO-EMCH, forming a maleimide bridge in this study (i.e., T10-DOX and T15-DOX). The structures and properties of peptide–DOX conjugates were characterized using <sup>1</sup>H NMR, <sup>13</sup>C NMR, mass spectrometry, and high-performance liquid chromatography. Their stability was also evaluated. By using MCF-7/ADR cells as an <i>in vitro</i> model system and nude mice bearing MCF-7/ADR xenografts as an <i>in vivo</i> model, the ability of these novel peptide–DOX conjugates to reverse drug resistance was accessed as compared with free DOX. As a result, the IC<sub>50</sub> values for T10-DOX and T15-DOX significantly decreased (31.6 ± 1.6 μM and 27.2 ± 0.8 μM), whereas the percentage of apoptotic cell population increased (35.4% and 39.3%). The <i>in vivo</i> extent of inhibition was more evident in the mice groups treated with peptide–DOX conjugates (59.6 ± 8.99% and 46.4 ± 6.63%), which had DOX primarily accumulated in tumor. These conjugates also showed a longer half-life in plasma and cleared much more slowly from the body. Furthermore, T10-DOX may be more effective than T15-DOX with a higher efficacy and a lower side effect. Most importantly, evidence was provided to support the enhanced intracellular drug accumulation and the induction of lysosomal pathway of apoptosis underlying the drug resistance. As an endosomal/lysosomal marker, cathepsin D permealized the destabilized organelle membrane and was detected in the cytoplasm, leading to the activation of the effector caspase-3 in cell apoptosis. This report is among the first to demonstrate that peptide–DOX-like conjugates promote apoptosis through the initiation of the lysosomal pathway

    Simultaneous Quantification of Protein Phosphorylation Sites using Liquid Chromatography–Tandem Mass Spectrometry-Based Targeted Proteomics: A Linear Algebra Approach for Isobaric Phosphopeptides

    No full text
    As one of the most studied post-translational modifications (PTM), protein phosphorylation plays an essential role in almost all cellular processes. Current methods are able to predict and determine thousands of phosphorylation sites, whereas stoichiometric quantification of these sites is still challenging. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS)-based targeted proteomics is emerging as a promising technique for site-specific quantification of protein phosphorylation using proteolytic peptides as surrogates of proteins. However, several issues may limit its application, one of which relates to the phosphopeptides with different phosphorylation sites and the same mass (i.e., isobaric phosphopeptides). While employment of site-specific product ions allows for these isobaric phosphopeptides to be distinguished and quantified, site-specific product ions are often absent or weak in tandem mass spectra. In this study, linear algebra algorithms were employed as an add-on to targeted proteomics to retrieve information on individual phosphopeptides from their common spectra. To achieve this simultaneous quantification, a LC–MS/MS-based targeted proteomics assay was first developed and validated for each phosphopeptide. Given the slope and intercept of calibration curves of phosphopeptides in each transition, linear algebraic equations were developed. Using a series of mock mixtures prepared with varying concentrations of each phosphopeptide, the reliability of the approach to quantify isobaric phosphopeptides containing multiple phosphorylation sites (≥2) was discussed. Finally, we applied this approach to determine the phosphorylation stoichiometry of heat shock protein 27 (HSP27) at Ser78 and Ser82 in breast cancer cells and tissue samples
    corecore