[en] Full density Nb₂O₅-BaO-Na₂O-SiO₂ Glass-ceramics, which could be used as the dielectric energy-storage materials to fabricate high energy density devices, were prepared by means of rapid quenching and succeeding annealing under different temperature. DTA and X-ray diffraction analysis showed that NaBa₂Nb₅O₁₅ with tungsten bronze structure and NaNbO₃ with perovskite structure were formed as the dielectric phases from the glass matrix at above 750 deg. C. Dielectric constant of the crystallized glass-ceramics were measured at the frequency from 100 Hz to 100 kHz under the testing temperature from -40 to 150 deg. C. The results indicated that theoretical energy storage density of the material crystallized at 800 deg. C could reach up to 1.87x10⁶J/m³, which would be suitable to be used as the innoxious dielectric media for high-energy storage capacitors.

[en] Large-sized (Pb, Sr)Nb₂O₆-NaNbO₃-SiO₂ glass ceramic plate was fabricated via melt-quenching followed by controlled crystallization. Its dielectric properties and charge-discharge properties were investigated. The results show that the dielectric constant is about 340 and has good temperature and voltage stability. The output pulse width of glass-ceramic pulse forming line is about 89 ns, and shows good flatness and steep front edge. The charge-discharge lifetime of pulse forming line is larger than one million times under the charge voltage of 19 kV, discharge current of 4 kA and operating frequency of 1 kHz. (authors)

[en] Bulk Na₂O-BaO-PbO-Nb₂O₅-SiO₂ glass-ceramic dielectrics in considerable size (about 200x100x5mm³) were prepared via controlled-crystallization route. The dielectric properties (including the permittivity and the loss tangent) of the bulk dielectrics were investigated. The results show that the capability of charge or energy storage in the bulk dielectrics is relatively lower than that of anticipation based on thinner and smaller specimen, due to the serious breakdown strength (BDS) drop of the bulk dielectrics. Several electrode structures were designed and applied in the measurement circuit to enhance the BDS of the bulk dielectrics. Among which, a bowl-like electrode structure was proved to reduce electrode edge effect most effectively in the BDS measurement.

[en] Nanoparticular MRI contrast agents are rapidly becoming suitable for use in clinical diagnosis. An ideal nanoparticular contrast agent should be endowed with high relaxivity, biocompatibility, proper plasma retention time, and tissue-specific or tumor-targeting imaging. Herein we introduce PEGylated KMnF₃ nanoparticles as a new type of T₁ contrast agent. Studies showed that the nanoparticular contrast agent revealed high bio-stability with bovine serum albumin in PBS buffer solution, and presented excellent biocompatibility (low cytotoxicity, undetectable hemolysis and hemagglutination). Meanwhile the new contrast agent possessed proper plasma retention time (circulation half-life t_1/2 is approximately 2 h) in the body of the administrated mice. It can be delivered into brain vessels and maintained there for hours, and is mostly cleared from the body within 48 h, as demonstrated by time-resolved MRI and Mn-biodistribution analysis. Those distinguishing features make it suitable to obtain contrast-enhanced brain magnetic resonance angiography. Moreover, through the process of passive targeting delivery, the T₁ contrast agent clearly illuminates a brain tumor (glioma) with high contrast image and defined shape. This study demonstrates that PEGylated KMnF₃ nanoparticles represent a promising biocompatible vascular contrast agent for magnetic resonance angiography and can potentially be further developed into an active targeted tumor MRI contrast agent. (paper)

[en] Degradation is the long-existing toxic issue of metal-containing inorganic medicine. In this paper, we fully investigated the degradation of dextran-coated KMnF_3 nanocube in the in vitro and in vivo surroundings. Different from the general decomposing and ion releasing events, this special agent is resistant to acidic environment, as well as ion exchange. Non-degradability was proved by simulated and real cellular experiments. Moreover, it can be engulfed in the macrophage cells and kept stable in the lysosome. Due to its stability and highly selective phagocytosis, implanted liver cancer can be clearly visualized after administration

[en] Highlights: • Nanoflake Nd-metal-organic framework has been synthesized for the first time via a simple hydrothermal method. • It presents an active material for the rapid and reliable electrochemical detection of Rhodamine B. • This method provides a new strategy for Rhodamine B detection using MOF materials. A novel neodymium-based metal-organic framework (Nd-MOF) {[Nd₂(Hpdc)₃(H₂O)₆]·3H₂O}_n (H₃pdc​=​1H-pyrazole-3,5-dicarboxylic acid) was synthesized by a simple hydrothermal method and structurally characterized. By dropped onto glassy carbon electrodes (GCE), the prepared Nd-MOF was applied to construct an efficient electrochemical sensor for the rapid and reliable electrochemical detection of Rhodamine B (RhB). This proposed Nd-MOF/GCE sensor exhibited strong accumulation ability and high electrocatalytic activity for RhB. Electrochemical oxidation signal of RhB at the Nd-MOF/GCE was greatly enhanced as compared to that at the bare GCE. The effective factors such as pH of buffer solution, amount of Nd-MOF suspension and accumulation time were optimized for the quantitative detection of RhB. Under optimum conditions, the fabricated sensor showed two wide linear ranges of 0.08–2.0 and 2.0–40​μM with a low detection limit of 3.6​nM, which was ascribed to the advantages of Nd-MOF such as large specific surface area, multiple active sites, strong accumulation ability. Moreover, the developed Nd-MOF/GCE sensor displayed good selectivity and accuracy towards RhB detection in the actual samples. Thus, this simple and efficient approach for RhB detection has good prospective for application in environmental monitoring.

[en] We report a new type of dual modal nanoprobe to combine optical and magnetic resonance bioimaging. A simple reverse microemulsion method and coating process was introduced to synthesize silica-coated Gd₂(CO₃)₃:Tb nanoparticles, and the particles, with an average diameter of 16 nm, can be dispersed in water. As in vitro cell imaging of the nanoprobe shows, the nanoprobe accomplishes delivery to gastric SGC7901 cancer cells successfully in a short time, as well as NCI-H460 lung cancer cells. Furthermore, it presents no evidence of cell toxicity or adverse affect on kidney cell growth under high dose, which makes the nanoprobe’s optical bioimaging modality available. The possibility of using the nanoprobe for magnetic resonance imaging is also demonstrated, and the nanoprobe displays a clear T₁-weighted effect and could potentially serve as a bimodal T₁-positive contrast agent. Therefore, the new nanoprobe formed from carbonate nanoprobe doped with rare earth ions provides the dual modality of optical and magnetic resonance imaging. (paper)

[en] Multidrug resistance (MDR) is a major reason for failure of chemotherapy in a variety of human tumors. For instance, paclitaxel (PTX) has been widely used as a first-line anticancer drug, but resistance to PTX is becoming increasingly serious. Herein, we propose a strategy of combined therapy to overcome MDR of PTX by introducing a hybrid paclitaxel-loaded gadolinium arsenite nanoparticle (HPAN), where PTX was conjugated with rod-shaped gadolinium arsenite (GdAsO_x) nanoparticle (NP). Triggered by endogenous inorganic phosphate (Pi), the hybrid nanoparticles readily collapse, thereby releasing PTX and arsenic trioxide (ATO). An MTT assay indicated IC50 values for HPAN one order of magnitude lower than for a simple equivalent mixture of PTX and ATO against PTX-resistant human colon cancer cells (HCT 166), indicating remarkable synergistic effect. Species type-dependent cellular uptake, induced apoptosis, and cell cycle modulation were also evaluated. Cellular uptake tests indicate that the HPAN presents higher PTX intracellular loading for the PTX-resistant cells and longer intracellular retention time, displaying resistance to drug efflux from the cancer cell than pristine PTX or the equivalent mixture of PTX and ATO. Cell cycle and apoptosis tests consistently proved that addition of HPAN resulted in higher G2/M and apoptosis in PTX-resistant cells. In vivo anticancer experiments evidenced that HPAN had better therapeutic effect on the resistant tumor in the murine xenograft model than pristine PTX or a mixture of PTX and ATO. Our results suggest that HPAN might enhance the therapeutic index and overcome PTX resistance and also demonstrate that the combined therapy is not only related to the species of combined agents but also their physiochemical states.

[en] To assess the association of ectopic fat deposition in the liver and pancreas quantified by Dixon magnetic resonance imaging (MRI) with insulin sensitivity and β-cell function in patients with central obesity. A cross-sectional study of 143 patients with central obesity with normal glucose tolerance (NGT), prediabetes (PreD), and untreated type 2 diabetes mellitus (T2DM) was conducted between December 2019 and March 2022. All participants underwent routine medical history taking, anthropometric measurements, and laboratory tests, including a standard glucose tolerance test to quantify insulin sensitivity and β-cell function. The fat content in the liver and pancreas was measured with MRI using the six-point Dixon technique. Patients with T2DM and PreD had a higher liver fat fraction (LFF) than those with NGT, while those with T2DM had a higher pancreatic fat fraction (PFF) than those with PreD and NGT. LFF was positively correlated with homeostatic model assessment of insulin resistance (HOMA-IR), while PFF was negatively correlated with homeostatic model assessment of insulin secretion (HOMA-β). Furthermore, using a structured equation model, we found LFF and PFF to be positively associated with glycosylated hemoglobin via HOMA-IR and HOMA-β, respectively. In patients with central obesity, the effects of LFF and PFF on glucose metabolism. were associated with HOMA-IR and HOMA-β, respectively. Ectopic fat storage in the liver and pancreas quantified by MR Dixon imaging potentially plays a notable role in the onset ofT2DM. We highlight the potential role of ectopic fat deposition in the liver and pancreas in the development of type 2 diabetes in patients with central obesity, providing valuable insights into the pathogenesis of the disease and potential targets for intervention.

[en] A series of lanthanide-organic complexes based on polyoxometalates (POMs) [Ln₂(DNBA)₄(DMF)₈][W₆O₁₉] (Ln=La(1), Ce(2), Sm(3), Eu(4), Gd(5); DNBA=3,5-dinitrobenzoate; DMF=N,N-dimethylformamide) has been synthesized. These complexes consist of [W₆O₁₉]²⁻ and dimeric [Ln₂(DNBA)₄(DMF)₈]²⁺ cations. The luminescence properties of 4 are measured in solid state and different solutions, respectively. Notably, the emission intensity increases gradually with the increase of solvent permittivity, and this solvent effect can be directly observed by electrospray mass spectrometry (ESI-MS). The analyses of ESI-MS show that the eight coordinated solvent DMF units of dimeric cation are active. They can move away from dimeric cations and exchange with solvent molecules. Although the POM anions escape from 3D supramolecular network, the dimeric state structure of [Ln₂(DNBA)₄]²⁺ remains unchanged in solution. The conservation of red luminescence is attributed to the maintenance of the aggregated state structures of dimeric cations. - Graphical abstract: 3D POMs-based lanthanide-organic complexes performed the solvent effect on the luminescence property. The origin of such solvent effect can be understood and explained on the basis of the existence of coordinated active sites by the studies of ESI-MS. Highlights: ► The solvent effect on the luminescence property of POMs-based lanthanide-organic complexes. ► ESI-MS analyses illuminate the correlation between the structure and luminescence property. ► The dimeric cations have eight active sites of solvent coordination. ► The aggregated state structure of dimer cation remains unchanged in solution. ► Luminescence associating with ESI-MS is a new method for investigating the interaction of complex and solvent.