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1.
Mater Horiz ; 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38868994

ABSTRACT

O3-type layered oxide cathodes are promising for practical sodium-ion batteries (SIBs) owing to their high theoretical capacity, facile synthesis, and sufficient Na+ storage. However, they face challenges such as rapid capacity loss and poor cycling stability, mainly attributed to irreversible phase transitions. To address these challenges, a novel cathode material, Li/Sn co-substituted O3-Na0.95Li0.07Sn0.01Ni0.22Fe0.2Mn0.5O2 (LSNFM), has been designed by regulating the electronic structure, in which Li+ activates more redox reactions of Ni2+/3+ and Fe3+/4+ above 2.5 V and suppresses the redox reactivity of Mn3+/4+ below 2.5 V, while Sn4+ can prevent the charge delocalization in the transition metal layer, contributing to structural stability. Due to this synergistic effect, the as-prepared LSNFM electrode with high structural reversibility displays a 27.2% capacity increase contributed by the high-voltage transition metal ion redox activity and exhibits excellent long-term cycling stability, an 84.0% capacity retention after 500 cycles at 1 C and an 84.7% capacity retention after 2000 cycles at 5 C. The fundamental mechanism is fully investigated using systematic in situ/ex situ characterization techniques and density functional theory computations. This work provides a paradigm for designing long-term cycle life cathode materials by synergistically regulating the electronic structure in practical SIBs.

2.
iScience ; 27(4): 109557, 2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38623342

ABSTRACT

Rechargeable lithium-ion batteries (LIBs) have prospered a rechargeable world, predominantly relying on various metal oxide cathode materials for their abilities to reversibly de-/intercalate lithium-ion, while also serving as lithium sources for batteries. Despite the success of metal oxide, issues including low energy density have raised doubts about their suitability for next-generation lithium batteries. This has sparked interest in metal chlorides, a neglected cathode material family. Metal chlorides show promise with factors like energy density, diffusion coefficient, and compressibility. Unfortunately, challenges like high solubility hamper their utilization. In this review, we highlight the opportunities for metal chlorides in the post-lithium-ion era. Subsequently, we summarize their dissolution challenges. Furthermore, we discuss recent advancements, encompassing liquid-state electrolyte engineering, solid-state electrolytes (SSEs) cooperation, and LiCl-based cathodes. Finally, we provide an outlook on future research directions of metal chlorides, emphasizing electrode fabrication, electrolyte design, the application of SSEs, and the exploration of conversion reactions.

3.
ACS Appl Mater Interfaces ; 15(22): 26691-26699, 2023 Jun 07.
Article in English | MEDLINE | ID: mdl-37246628

ABSTRACT

Sodium metal batteries are ideal candidates for next-generation grid-level energy storage systems. However, severe obstacles pertain with regard to the usage of metallic Na, including poor processability, dendrite growth, and violent side reactions. Herein, we design a "carbon in metal" anode (denoted as CiM) via a facile method by rolling a controllable amount of mesoporous carbon powder into the Na metal. The as-designed composite anode is endowed with dramatically lowered stickiness and increased hardness (3 times higher than that of pure Na metal) and strength along with improved processability, which can be fabricated into foils with varied patterns and limited thickness (down to 100 µm). Besides, nitrogen-doped mesoporous carbon, which can increase the sodiophilicity, is applied to fabricate N-doped carbon in the metal anode (denoted as N-CiM), which can effectively facilitate the diffusion of Na+ ions and decrease the depositing overpotential, consequently homogenizing the Na+-ion flow and rendering a dense and flat Na deposition. Therefore, the N-CiM anode offers enhanced cycling stability for 800 h at 1 mAh cm-2 in symmetric cells and 1000 cycles with a high average Coulomb efficiency (CE) (99.8%) in full cells based on the conventional carbonate electrolyte.

4.
ACS Appl Mater Interfaces ; 15(12): 15235-15249, 2023 Mar 29.
Article in English | MEDLINE | ID: mdl-36926829

ABSTRACT

Two major issues are currently hindering the clinical practice of titanium dental implants for the lack of biological activities: immediate/early loading risks and peri-implantitis. To solve these issues, it is urgent to develop multifunctional implants modified with effective osteogenic and antibacterial properties. Zinc oxide nanoparticles (ZnO NPs) possess superior antibacterial activity; however, they can rapidly release Zn2+, causing cytotoxicity. In this study, a potential dental implant modification was creatively developed as ZnO nanoparticle-loaded mesoporous TiO2 coatings (nZnO/MTC-Ti) via the evaporation-induced self-assembly method (EISA) and one-step spin coating. The mesoporous TiO2 coatings (MTCs) regulated the synthesis and loading of ZnO NPs inside the nanosized pores. The synergistic effects of MTC and ZnO NPs on nZnO/MTC-Ti not only controlled the long-term steady-state release of Zn2+ but also optimized the charge distribution on the surface. Therefore, the cytotoxicity of ZnO NPs was resolved without triggering excessive reactive oxygen species (ROS). The increased extracellular Zn2+ further promoted a favorable intracellular zinc ion microenvironment through the modulation of zinc transporters (ZIP1 and ZnT1). Owing to that, the adhesion, proliferation, and osteogenic activity of bone mesenchymal stem cells (BMSCs) were improved. Additionally, nZnO/MTC-Ti inhibited the proliferation of oral pathogens (Pg and Aa) by inducing bacterial ROS production. For in vivo experiments, different implants were implanted into the alveolar fossa of Sprague-Dawley rats immediately after tooth extraction. The nZnO/MTC-Ti implants were found to possess a higher capability for enhancing bone regeneration, antibiosis, and osseointegration in vivo. These findings suggested the outstanding performance of nZnO/MTC-Ti implants in accelerating osseointegration and inhibiting bacterial infection, indicating a huge potential for solving immediate/early loading risks and peri-implantitis of dental implants.


Subject(s)
Dental Implants , Peri-Implantitis , Zinc Oxide , Rats , Animals , Zinc Oxide/pharmacology , Titanium/pharmacology , Reactive Oxygen Species/pharmacology , Rats, Sprague-Dawley , Osteogenesis , Zinc/pharmacology , Anti-Bacterial Agents/pharmacology , Surface Properties , Coated Materials, Biocompatible/pharmacology
5.
Am J Clin Exp Urol ; 11(1): 12-26, 2023.
Article in English | MEDLINE | ID: mdl-36923722

ABSTRACT

Benign prostatic hyperplasia (BPH) is a non-neoplastic proliferative disease producing lower urinary tract symptoms related to the resulting enlarged prostate. BPH is pathologically characterized by hyperplastic growth in both epithelial and stromal compartments. Androgen signaling is essential for prostate function and androgen blockade is the second-line medical therapy to relieve symptoms of BPH. Here we examined the prostates of probasin promoter-driven prolactin (Pb-PRL) transgenic mice, a robust model of BPH that spontaneously develops prostate enlargement, to investigate prostate regression in response to surgical castration. Serial ultrasound imaging demonstrated very uniform self-limited growth of Pb-PRL prostate volume that is consistent with the benign, limited cellular proliferation characteristic of BPH and that contrasts with the highly variable, exponential growth of murine prostate cancer models. Castration elicited only a partial reduction in prostate volume, relative to castration-induced regression of the normal prostate gland. The anti-androgen finasteride induced a diminished reduction of Pb-PRL prostate volume versus castration. The limited extent of Pb-PRL mouse prostate volume regression correlated with the initial volume of the stromal compartment, suggesting a differential sensitivity of the epithelial and stromal compartments to androgen withdrawal. Indeed, two-dimensional morphometric analyses revealed a distinctly reduced rate of regression for the stromal compartment in Pb-PRL mice. The myofibroblast component of the Pb-PRL prostate stroma appeared normal, but the stromal compartment contained more fibroblasts and extracellular collagen deposition. Like normal prostate, the rate of regression of the Pb-PRL prostate was partially dependent on TGFß and TNF signaling, but unlike the normal prostate, the extent of castration-induced regression was not affected by TGFß or TNF blockade. Our studies show that androgen deprivation can effectively reduce the overall volume of hyperplastic prostate, but the stromal compartment is relatively resistant, suggesting additional therapies might be required to offer an effective treatment for the clinical manifestations of BPH.

6.
Water Res ; 235: 119842, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36921357

ABSTRACT

Advanced oxidation processes (AOPs) have been widely used in water and wastewater treatment and have shown excellent performance in remediating contaminated water. However, their oxidation byproducts, including halogenated organics, have recently attracted increasing attention. Alkyl halides are among the most important environmental pollutants in nature. Here, we report a Fenton-like reaction in which alkyl halides can form during the photodegradation of aliphatic carboxylic acids in the presence of Fe(III) and halides. Chloromethane, chloroethane, and 1-chloropropane were produced from the degradation of acetic acid, propionic acid and n-butyric acid, respectively. CH3Cl, CH2Cl2 and CHCl3 were all identified as the products of acetic acid with the yields of approximately 5.1%, 0.2% and 0.005%, respectively. It was demonstrated that hydroxyl radicals, halogen radicals and alkyl radicals were involved in the formation of alkyl halides. A possible mechanism of chloromethane formation was proposed based on the results. In real samples of saline water, the addition of carboxylic acid and Fe(III) significantly promoted the generation of CH3Cl under xenon lamp irradiation. The results indicated that the coexistence of Fe(III), halides and carboxylic acids enhanced the photochemical release of alkyl halides. The reactions described in this paper may contribute to knowledge on the mechanism of halogenated byproduct formation during AOPs.


Subject(s)
Methyl Chloride , Water Pollutants, Chemical , Carboxylic Acids , Ferric Compounds , Oxidation-Reduction , Hydroxyl Radical , Hydrogen Peroxide
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 4453-4456, 2022 07.
Article in English | MEDLINE | ID: mdl-36086600

ABSTRACT

Recently there has seen promising results on auto-matic stage scoring by extracting spatio-temporal features from electroencephalogram (EEG). Such methods entail laborious manual feature engineering and domain knowledge. In this study, we propose an adaptive scheme to probabilistically encode, filter and accumulate the input signals and weight the resultant features by the half-Gaussian probabilities of signal intensities. The adaptive representations are subsequently fed into a transformer model to automatically mine the relevance between features and corresponding stages. Extensive exper-iments on the largest public dataset against state-of-the-art methods validate the effectiveness of our proposed method and reveal promising future directions.


Subject(s)
Electroencephalography , Sleep Stages , Electroencephalography/methods , Normal Distribution , Probability , Research Design
8.
Article in English | MEDLINE | ID: mdl-35951569

ABSTRACT

A hardware-friendly bisection neural network (BNN) topology is proposed in this work for approximately implementing massive pieces of complex functions in arbitrary on-chip configurations. Instead of the conventional reconfigurable fully connected neural network (FC-NN) circuit topology, the proposed hardware-friendly topology performs NN behaviors in a bisection structure, in which each neuron includes two constant synapse connections for both inputs and outputs. Compared with the FC-NN one, the reconfiguration of the BNN circuit topology eliminates the remarkable amount of dummy synapse connections in hardware. As the main target application, this work aims at building a general-purpose BNN circuit topology that offers a great amount of NN regressions. To achieve this target, we prove that the NN behaviors of the FC-NN circuit topologies can be migrated to the BNN circuit topologies equivalently. We introduce two approaches including the refining training algorithm and the inverted-pyramidal strategy to further reduce the number of neurons and synapses. Finally, we conduct the inaccuracy tolerance analysis to suggest the guideline for ultra-efficient hardware implementations. Compared with the state-of-the-art FC-NN circuit topology-based TrueNorth baseline, the proposed design can achieve 17.8-22.2 × hardware reduction and less than 1% inaccuracy.

9.
Nat Commun ; 13(1): 2133, 2022 04 19.
Article in English | MEDLINE | ID: mdl-35440548

ABSTRACT

Autoimmune (AI) diseases can affect many organs; however, the prostate has not been considered to be a primary target of these systemic inflammatory processes. Here, we utilize medical record data, patient samples, and in vivo models to evaluate the impact of inflammation, as seen in AI diseases, on prostate tissue. Human and mouse tissues are used to examine whether systemic targeting of inflammation limits prostatic inflammation and hyperplasia. Evaluation of 112,152 medical records indicates that benign prostatic hyperplasia (BPH) prevalence is significantly higher among patients with AI diseases. Furthermore, treating these patients with tumor necrosis factor (TNF)-antagonists significantly decreases BPH incidence. Single-cell RNA-seq and in vitro assays suggest that macrophage-derived TNF stimulates BPH-derived fibroblast proliferation. TNF blockade significantly reduces epithelial hyperplasia, NFκB activation, and macrophage-mediated inflammation within prostate tissues. Together, these studies show that patients with AI diseases have a heightened susceptibility to BPH and that reducing inflammation with a therapeutic agent can suppress BPH.


Subject(s)
Autoimmune Diseases , Prostatic Hyperplasia , Prostatitis , Animals , Autoimmune Diseases/drug therapy , Cell Line , Humans , Hyperplasia , Inflammation/drug therapy , Male , Mice , Prostatic Hyperplasia/drug therapy , Prostatic Hyperplasia/pathology
10.
J Exp Clin Cancer Res ; 40(1): 254, 2021 Aug 12.
Article in English | MEDLINE | ID: mdl-34384473

ABSTRACT

The incidence of renal cell carcinoma (RCC) is increasing worldwide with an approximate 20% mortality rate. The challenge in RCC is the therapy-resistance. Cancer resistance to treatment employs multiple mechanisms due to cancer heterogeneity with multiple genetic and epigenetic alterations. These changes include aberrant overexpression of (1) anticancer cell death proteins (e.g., survivin/BIRC5), (2) DNA repair regulators (e.g., ERCC6) and (3) efflux pump proteins (e.g., ABCG2/BCRP); mutations and/or deregulation of key (4) oncogenes (e.g., MDM2, KRAS) and/or (5) tumor suppressor genes (e.g., TP5/p53); and (6) deregulation of redox-sensitive regulators (e.g., HIF, NRF2). Foci of tumor cells that have these genetic alterations and/or deregulation possess survival advantages and are selected for survival during treatment. We will review the significance of survivin (BIRC5), XIAP, MCL-1, HIF1α, HIF2α, NRF2, MDM2, MDM4, TP5/p53, KRAS and AKT in treatment resistance as the potential therapeutic biomarkers and/or targets in RCC in parallel with our analized RCC-relevant TCGA genetic results from each of these gene/protein molecules. We then present our data to show the anticancer drug FL118 modulation of these protein targets and RCC cell/tumor growth. Finally, we include additional data to show a promising FL118 analogue (FL496) for treating the specialized type 2 papillary RCC.


Subject(s)
Biomarkers, Tumor/metabolism , Carcinoma, Renal Cell/diagnosis , Carcinoma, Renal Cell/therapy , Kidney Neoplasms/diagnosis , Kidney Neoplasms/therapy , Carcinoma, Renal Cell/pathology , Humans , Kidney Neoplasms/pathology
11.
ACS Cent Sci ; 6(2): 232-240, 2020 Feb 26.
Article in English | MEDLINE | ID: mdl-32123741

ABSTRACT

Sodium layered transition metal oxides have been considered as promising cathode materials for sodium ion batteries due to their large capacity and high operating voltage. However, mechanism investigations of chemical evolution and capacity failure at high voltage are inadequate. As a representative cathode, Na2/3Ni1/3Mn2/3O2, the capacity contribution at a 4.2 V plateau has long been assigned to the redox of the Ni3+/Ni4+ couple, while at the same time it suffers large irreversible capacity loss during the initial discharging process. In this work, we prove that the capacity at the 4.2 V plateau is contributed to the irreversible O2-/O2 n-/O2 evolution based on in situ differential electrochemical mass spectrometry and density functional theory calculation results. Besides, a phenomenon of oxygen release and subsequent surface lattice densification is observed, which is responsible for the large irreversible capacity loss during the initial cycle. Furthermore, the oxygen release is successfully suppressed by Fe substitution due to the formation of a unique Fe-(O-O) species, which effectively stabilizes the reversibility of the O2-/O2 n- redox at high operating voltage. Our findings provide a new understanding of the chemical evolution in layered transition metal oxides at high operating voltage. Increasing the covalency of the TM-O bond has been proven to be effective in suppressing the oxygen release and hence improving the electrochemical performance.

12.
ACS Appl Mater Interfaces ; 12(13): 15220-15227, 2020 Apr 01.
Article in English | MEDLINE | ID: mdl-32162902

ABSTRACT

Most of sodium-layered oxide cathodes are unstable under moisture conditions. As a unique water-stable cathode, Na2/3Ni1/3Mn2/3O2 (NNM) usually becomes vulnerable to water molecules after element substitution treatment to suppress the Na+ vacancy ordering arrangement, which causes limited Na+ diffusion kinetics. Herein, we show that these issues can be addressed simultaneously by rational designing the transition-metal (TM) layer to achieve both water-stable and Na+ vacancy disordering structures. Density functional theory calculations reveal that the water-stability of the layered oxide cathode can be correlated to the surface adsorption energy of H2O molecules. In the TM layer, the Co/Mn and Fe/Mn units exhibit a much lower adsorption energy than that of the Li/Mn unit, and hence the H2O molecule prefers to be absorbed on Co/Mn and Fe/Mn units rather than Li/Mn. Moreover, the Li/Mn unit in the TM layer can suppress the Na+ vacancy ordering structure in NNM to improve the Na+ diffusion kinetics. As a consequence, the well-designed Na2/3Li1/9Ni5/18Mn2/3O2 cathode can not only maintain its original crystal structure and electrochemical property after water soaking treatment but also exhibit high rate capability (78% capacity retention at 20 C) and excellent cycling stability (87% capacity retention after 1000 cycles).

13.
Front Chem ; 7: 335, 2019.
Article in English | MEDLINE | ID: mdl-31157208

ABSTRACT

Sodium-ion batteries are considered to be the most promising alternative to lithium-ion batteries for large-scale stationary energy storage applications due to the abundant sodium resource in the Earth' crust and as a result, relatively low cost. Sodium layered transition metal oxides (Na x TMO2) are proper Na-ion cathode materials because of low cost and high theoretical capacity. Currently most researchers focus on the improvement of electrochemical performance such as high rate capability and long cycling stability. However, for Na x TMO2, the structure stability against humid atmosphere is essentially important since most of them are instable in air, which is not favorable for practical application. Here we provide a comprehensive review of recent progresses on air-stable Na x TMO2 oxides. Several effective strategies are discussed, and further investigations on the air-stable cathodes are prospected.

14.
Nanotechnology ; 30(17): 175101, 2019 Apr 26.
Article in English | MEDLINE | ID: mdl-30654348

ABSTRACT

Arsenic trioxide (ATO), an FDA-approved drug for acute promyelocytic leukemia, also has great potential for treatment of solid tumors. Drug delivery powered by recent advances in nanotechnology has boosted the efficacy of many drugs, which is enlightening for applications of ATO in treating solid tumors. Herein, we reported arsenite-loaded multifunctional nanoparticles that are capable of pH-responsive ATO release for treating hepatocellular carcinoma (HCC) and real-time monitoring via magnetic resonance imaging. We fabricated these nanoparticles (designated as magnetic large-pore mesoporous silica nanoparticle (M-LPMSN)-NiAsO x ) by loading nanoparticulate ATO prodrugs (NiAsO x ) into the pores of large-pore mesoporous silica nanoparticles (LPMSNs) that contain magnetic iron oxide nanoparticles in the center. The surface of these nanodrugs was modified with a targeting ligand folic acid (FA) to further enhance the drug efficacy. Releasing profiles manifest the responsive discharging of arsenite in acidic environment. In vitro experiments with SMMC-7721 cells reveal that M-LPMSN-NiAsO x -FA nanodrugs have significantly higher cytotoxicity than traditional free ATO and induce more cell apoptosis. In vivo experiments with mice bearing H22 tumors further confirm the superior antitumor efficacy of M-LPMSN-NiAsO x -FA over traditional free ATO and demonstrate the outstanding imaging ability of M-LPMSN-NiAsO x -FA for real-time tumor monitoring. These targeted arsenite-loaded magnetic mesoporous silica nanoparticles integrating imaging and therapy hold great promise for treatment of HCC, indicating the auspicious potential of LPMSN-based nanoplatforms.


Subject(s)
Antineoplastic Agents/administration & dosage , Arsenites/administration & dosage , Carcinoma, Hepatocellular/drug therapy , Drug Carriers , Liver Neoplasms/drug therapy , Magnetite Nanoparticles/chemistry , Animals , Antineoplastic Agents/pharmacokinetics , Arsenites/chemistry , Arsenites/pharmacokinetics , Cell Line, Tumor , Drug Carriers/administration & dosage , Drug Carriers/chemistry , Female , Humans , Magnetite Nanoparticles/administration & dosage , Mice, Inbred BALB C
15.
Adv Mater ; 30(17): e1705630, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29513368

ABSTRACT

Novel carbon nanomaterials have aroused significant interest owing to their prospects in various technological applications. The recently developed on-surface synthesis strategy provides a route toward atomically precise fabrication of nanostructures, which paves the way to functional molecular nanostructures in a controlled fashion. A plethora of low-dimensional nanostructures, challenging to traditional solution chemistry, have been recently fabricated. Within the last few decades, an increasing interest and flourishing studies on the fabrication of novel low-dimensional carbon nanostructures using on-surface synthesis strategies have been witnessed. In particular, carbon materials, including fullerene, carbon nanotubes, and graphene nanoribbons, are synthesized with atomic precision by such bottom-up methods. Herein, starting from the basic concepts and progress made in the field of on-surface synthesis, the recent developments of atomically precise fabrication of low-dimensional carbon nanostructures are reviewed.

16.
Sensors (Basel) ; 17(6)2017 Jun 17.
Article in English | MEDLINE | ID: mdl-28629140

ABSTRACT

In this paper, a new millimeter wave 3D imaging radar is proposed. The user just needs to move the radar along a circular track, and high resolution 3D imaging can be generated. The proposed radar uses the movement of itself to synthesize a large aperture in both the azimuth and elevation directions. It can utilize inverse Radon transform to resolve 3D imaging. To improve the sensing result, the compressed sensing approach is further investigated. The simulation and experimental result further illustrated the design. Because a single transceiver circuit is needed, a light, affordable and high resolution 3D mmWave imaging radar is illustrated in the paper.

17.
Sci Rep ; 6: 20769, 2016 Feb 12.
Article in English | MEDLINE | ID: mdl-26868049

ABSTRACT

Ultrahigh surface area single-crystals of periodic mesoporous organosilica (PMOs) with uniform cubic or truncated-cubic morphology and organic/inorganic components homogeneously distributed over the whole frameworks have successfully been prepared by a sol-gel surfactant-templating method. By tuning the porous feature and polymerization degree, the surface areas of the obtained PMO nanocubes can reach as high as 2370 m(2)/g, which is the highest for silica-based mesoporous materials. The ultrahigh surface area of the obtained PMO single crystals is mainly resulted from abundant micropores in the mesoporous frameworks. Furthermore, the diameter of the nanocubes can also be well controlled from 150 to 600 nm. The materials show ultrahigh CO2 adsorption capacity (up to 1.42 mmol/g at 273 K) which is much higher than other porous silica materials and comparable to some carbonaceous materials. The adsorption of CO2 into the PMO nanocubes is mainly in physical interaction, therefore the adsorption-desorption process is highly reversible and the adsorption capacity is much dependent on the surface area of the materials. Moreover, the selectivity is also very high (~11 times to N2) towards CO2 adsorption.

18.
ACS Appl Mater Interfaces ; 7(31): 17450-9, 2015 Aug 12.
Article in English | MEDLINE | ID: mdl-26192924

ABSTRACT

Immobilization of highly monodispersed palladium nanoparticles in colloidal mesoporous silica supports has been successfully achieved. The Pd nanoparticles with a uniform small size of ∼1.2 nm can be homogeneously distributed in individual mesopore channels of amino group-functionalized three-dimensional dendritic mesoporous silica nanospheres (3D-dendritic MSNSs) with a Pd content of ∼2.8%. The 3D-dendritic MSNSs-based nanoreactors show high activity in Suzuki-Miyaura cross-coupling reactions of bromobenzene with phenylboronic acid, obtaining a yield over 99% with 0.075 mol % Pd catalyst at room temperature in the dark within 12 h. More importantly, the excellent catalytic performance can be maintained with a negligible decrease lasting at least six cycles. It further reveals that the mesoporous frameworks of the colloidal silica supports can be well-preserved after four catalytic runs; meanwhile, the Pd nanoparticles in the mesopore channels also can remain the sizes of 1.5±0.3 nm without significant transfer and aggregation. The unique mesostructure of the 3D-dendritic MSNSs with mesopore channels of short length and large diameter is supposed to be the key role in immobilization of active and robust heterogeneous catalysts, and it would have more hopeful prospects in catalytic applications.

19.
Adv Mater ; 26(39): 6749-55, 2014 Oct 22.
Article in English | MEDLINE | ID: mdl-25164312

ABSTRACT

A magnesiothermic reduction approach is designed to synthesize mesoporous Si/C nanocomposites with ultrasmall, uniform silicon nanoparticles (ca. 3 nm) embedded in a rigid mesoporous carbon framework. The resultant mesoporous Si/C nanocomposites present excellent performance with high reversible capacity, good Coulombic efficiency and rate capability, and outstanding cycling stability in lithium-ion battery applications.

20.
Nano Lett ; 14(2): 923-32, 2014 Feb 12.
Article in English | MEDLINE | ID: mdl-24467566

ABSTRACT

A kind of novel uniform monodispersed three-dimensional dendritic mesoporous silica nanospheres (3D-dendritic MSNSs) has been successfully synthesized for the first time. The 3D-dendritic MSNSs can have hierarchical mesostructure with multigenerational, tunable center-radial, and dendritic mesopore channels. The synthesis was carried out in the heterogeneous oil-water biphase stratification reaction system, which allowed the self-assembly of reactants taking place in the oil-water interface for one-pot continuous interfacial growth. The average pore size of each generation for the 3D-dendritic MSNSs can be adjusted from 2.8 to 13 nm independently, which can be controlled by the varied hydrophobic solvents and concentration of silica source in the upper oil phase. The thickness of each generation can be tuned from ∼ 5 to 180 nm as desired, which can be controlled by the reaction time and amount of silica source. The biphase stratification approach can also be used to prepare other core-shell and functional mesoporous materials such as Au nanoparticle@3D-dendritic MSNS and Ag nanocube@3D-dendritic MSNS composites. The 3D-dendritic MSNSs show their unique advantage for protein loading and releasing due to their tunable large pore sizes and smart hierarchical mesostructures. The maximum loading capacity of bovine ß-lactoglobulin with 3D-dendritic MSNSs can reach as high as 62.1 wt % due to their large pore volume, and the simulated protein releasing process can be tuned from 24 to 96 h by flexible mesostructures. More importantly, the releasing rates are partly dependent on the hierarchical biodegradation, because the 3D-dendritic MSNSs with larger pore sizes have faster simulated biodegradation rates in simulated body fluid. The most rapid simulated biodegradation can be finished entirely in 24 h, which has been greatly shortened than two weeks for the mesoporous silica reported previously. As the inorganic mesoporous materials, 3D-dendritic MSNSs show excellent biocompatibility, and it would have a hopeful prospect in the clinical applications.


Subject(s)
Absorbable Implants , Drug Implants/chemical synthesis , Lactoglobulins/chemistry , Nanocapsules/chemistry , Nanospheres/chemistry , Silicon Dioxide/chemistry , Body Fluids/chemistry , Diffusion , Lactoglobulins/administration & dosage , Materials Testing , Nanocapsules/ultrastructure , Nanopores/ultrastructure , Nanospheres/ultrastructure , Particle Size , Phase Transition , Porosity , Surface Properties
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