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1.
Small ; : e2401387, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38773909

RESUMO

Bulk hexagonal boron nitride (h-BN) ceramics with structural integrity, high-temperature resistance and low expansion rate are expected for multifunctional applications in extreme conditions. However, due to its sluggish self-diffusion and intrinsic inertness, it remains a great challenge to overcome high-energy barrier for h-BN powder sintering. Herein, a cross-linking and pressureless-welding strategy is reported to produce bulk boron nitride nanosheets (BNNSs) ceramics with well-crystalized and dense B-N covalent-welding frameworks. The essence of this synthesis strategy lies in the construction of >B─O─H2C─H2C─H2N:→B< bond bridge connection structure among hydroxyl functionalized BNNSs (BNNSs-OH) using bifunctional monoethanolamine (MEA) as cross-linker through esterification and intermolecular-coordination reactions. The prepared BNNSs-interlaced ceramics have densities not less than 1.2 g cm-3, and exhibit exceptional mechanical robustness and resiliency, excellent thermomechanical stability, ultra-low linear thermal expansion coefficient of 0.06 ppm °C-1, and high thermal diffusion coefficient of 4.76 mm2 s-1 at 25 °C and 3.72 mm2 s-1 at 450 °C. This research not only reduces the free energy barrier from h-BN particles to bulk ceramics through facile multi-step physicochemical reaction, but also stimulates further exploration of multifunctional applications for bulk h-BN ceramics over a wide temperature range.

2.
Chemosphere ; 345: 140530, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37890791

RESUMO

A template-free pyrolysis route has been developed using condensation-assembly precursors made of trimethoxyboroxane (TMB) and melamine (M) to cater the requirements of an industrial real-world environment. The precursors contain abundant B-N bonds and exhibit a high level of interconnectivity, resulting in 3D-PBN with enhanced mechanical properties and the ability to be easily customized in terms of shape. Moreover, 3D-PBN demonstrates rapid adsorption kinetics and excellent reusability, efficiently removing up to 270% of its own weight of fuel within 30 s and being readily regenerated through simple calcination. Even after undergoing 50 cycles, the mechanical properties remain at a remarkable 80%, while the adsorption performance exceed 95%. Furthermore, a comprehensive analysis of thermal behavior from precursor to 3D-PBN has been conducted, leading to the proposal of a molecular-scale evolution process comprising four major steps. This understanding enables us to control the phase reaction and regulate the composition of the products, which is crucial for determining the characteristics of the final product.


Assuntos
Compostos de Boro , Porosidade , Compostos de Boro/química
3.
ACS Omega ; 8(17): 15239-15248, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37151536

RESUMO

Microspheric BN materials have high application potential because they have better fluidity and dispersion ability to endow hexagonal boron nitride (h-BN) ceramics and h-BN/polymer composites with highly desired performance. In this work, a novel synthetic route to the BN microspheres has been developed by means of a controllable pyrolysis of polymerized spherical precursors. The precursor formation mechanism is proposed to be the F-127-induced self-assembling polymerization of a boric acid-melamine-formaldehyde (MF) colloid. It is found that ammonia-annealing of an air-pyrolysis (700 °C) intermediate causes higher BN phase transformation within final BN microspheres with more uniform diameter distribution compared to those of direct ammonia-pyrolysis of spherical precursors at the same temperatures of 1100 and 1500 °C. After ammonia-annealing and ammonia-pyrolyzed treatment at 1100 and 1500 °C, the obtained BN microspheres have a low specific surface area (SSA) property, but replacing part of melamine with dicyandiamide could increase their SSAs to more than 1000 m2/g. We believe that this new microspherical BN preparation with more facile and controllable operation would be well suited for industrialization.

4.
Folia Neuropathol ; 61(1): 97-104, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37114965

RESUMO

INTRODUCTION: The aim of the study was to explore the analgesic mechanism of effects of intrathecally administered interferon a (IFN-a) on chronic constriction injury (CCI) model rats. MATERIAL AND METHODS: 24 rats were divided into 6 groups, with 4 rats in each group, including the negative control group (Group N, no operation or treatment), the sham operation group (Group S, only the left sciatic nerve of the rats was exposed without ligation, 0.9% NaCl was intrathecally administered), and four experimental groups (CCI model was established first and then different drugs were intrathecally administered respectively), including 0.9% NaCl (Group C), IFN-a (Group CI), morphine (Group CM), and IFN-a combined with morphine (Group CIM). The mRNA levels of G proteins in both the spinal cord and dorsal root ganglia (DRG), as well as the content of amino acid and chemokine (C-X-C motif) ligand 6 (CXCL-6) in the cerebrospinal fluid were measured and analysed in each group. RESULTS: Intrathecal administration of IFN-a increased the mechanical pain threshold in CCI rats (33.32 ±1.36 vs. 21.08 ±1.59, p < 0.001), achieving the effect comparable to that of morphine (33.32 ±1.36 vs. 32.44 ±3.18, p > 0.05), increased the mRNA expression level of Gi protein (0.62 ±0.04 vs. 0.49 ±0.05, p = 0.006), and decreased the mRNA expression level of Gs protein in the spinal cord (1.80 ±0.16 vs. 2.06 ±0.15, p = 0.035) and DRG (2.11 ±0.10 vs. 2.79 ±0.13, p < 0.001). The intrathecal administration of both IFN-a and morphine can reduce the glutamate content in the cerebrospinal fluid (261.55 ±38.12 vs. 347.70 ±40.69, p = 0.012), but without any statistically significant difference in the content of CXCL-6 across all groups ( p > 0.05). CONCLUSIONS: Intrathecal injection of IFN-a improved the mechanical pain threshold in CCI rats, so we inferred that intrathecal administration of IFN-a had analgesic effects on neuropathic pain, possibly related to the activation of G-proteincoupled µ receptors in the spinal cord and the inhibition of glutamate release.


Assuntos
Interferon-alfa , Limiar da Dor , Ratos , Animais , Ratos Sprague-Dawley , Interferon-alfa/farmacologia , Interferon-alfa/metabolismo , Constrição , Solução Salina/metabolismo , Solução Salina/farmacologia , Proteínas de Ligação ao GTP/metabolismo , Proteínas de Ligação ao GTP/farmacologia , RNA Mensageiro/metabolismo , Medula Espinal/metabolismo , Derivados da Morfina/metabolismo , Derivados da Morfina/farmacologia
5.
ACS Appl Mater Interfaces ; 15(4): 5760-5773, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36649561

RESUMO

Although this kind of hexagonal boron nitride (h-BN)-filled polydimethylsiloxane (PDMS) multifunctional composite foam has been greatly expected, its development is still relatively slow as a result of the limitation of synthetic challenge. In this work, a new foaming process of BNNSs-PDMS, alcohol, and water three-phase emulsion system is employed to synthesize a series of high-quality BNNSs/PDMS composite foams (BSFs) filled with highly functional and uniformly distributed BNNSs. As a result of well-bonded interfaces between the BNNSs and PDMS, enhanced multiple functions of BSFs appeared. The BSFs can show complete resilience at a compressive strain of 90% and only 3.99% irreversible deformation after 100,000 compressing-releasing hyperelastic cycles at a strain of 60%. On the basis of their outstanding shape-memory properties, the maximum voltage value of compression-driven piezo-triboelectric (CDPT) responses of the BSFs is up to ∼20 V. Depending on the remarkable super-elastic and CDPT performances, the BSFs can be used for sensitive sensing of temperature difference and electromechanical responses. Also, in the range of 12-40 GHz, the BSF materials display ultralow dielectric constants between 1.1 and 1.4 with proper dielectric loss tangent values of <0.3 and exhibit an enhanced and broadened sound adsorption capacity ranging from 500 to 6500 Hz. Although BSFs have high porosities of >65%, their thermal conductivities can still reach up to 0.407 ± 0.039 W m-1 K-1. Moreover, the BSF materials display favorable thermal stability, obviously reduced coefficient of thermal expansion, and good flame retardancy. All of these properties render the BSFs as a new category of excellent multifunctional material.

6.
ACS Appl Mater Interfaces ; 14(43): 48558-48569, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36263683

RESUMO

Lithium-sulfur (Li-S) batteries with high theoretical energy density are considered as the most promising devices for rechargeable energy-storage systems. However, their actual applications are rather limited by the shuttle effect of lithium polysulfides (LiPSs) and the sluggish redox kinetics. Here, the boron nitride nanosheets are homodispersedly embedded into N-doping porous carbon fibers (BNNSs/CHFs) by an electrospinning technique and a subsequent in situ pyrolysis process. The hybridized BNNSs/CHFs can be smartly designed as a multifunctional separation coating onto the commercial PP membrane to enhance the electrochemical performance of Li-S batteries. As a result, the Li-S batteries with extra BNNSs/CHF modification deliver a highly reversible discharge capacity of 830.4 mA h g-1 at a current density of 1 C. Even under 4 C, the discharge specific capacity can reach up to 609.9 mA h g-1 and maintain at 553.9 mA h g-1 after 500 cycles, showing a low capacity decay of 0.01836% per cycle. It is considered that the excellent performance is attributed to the synergistic effect of adsorption and catalysis of the BNNSs/CHF coating used. First, this coating can efficiently reduce the charge transfer resistance and enhance Li-ion diffusion, due to increased catalytic activity from strong electronic interactions between BNNSs and N-doping CHFs. Second, the combination of polar BNNSs and abundant pore structures within the hybridized BNNSs/CHF networks can highly facilitate an adsorption for LiPSs. Here, we believed that this work would provide a promising strategy to increase the Li-S batteries' performance by introducing hybridized BNNSs/N-doping carbon networks, which could efficiently suppress the LiPSs' shuttle effect and improve the electrochemical kinetics of Li-S batteries.

7.
J Am Chem Soc ; 144(13): 5930-5936, 2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35316601

RESUMO

Boron nitride (BN) has been widely studied as an efficient catalyst for oxidative propane dehydrogenation (OPDH). Oxygen-containing boron species (e.g., BO·, B(OH)xO3-x) are generally considered as the active centers in BN for OPDH. Here, we show an effective progressive substitution strategy toward the development of boron-oxygen-nitrogen nanotubes (BONNTs) enriched with O-O species as a highly active, selective, and stable catalyst for OPDH. At 525 °C, an olefin yield of 48.6% is achieved over BONNTs with a propane conversion of 64.4%, 2.8 times that of boron nitrogen nanotubes (BNNTs). Even after reaction for 150 h (475 °C), BONNTs exhibit good olefin yield. Both the B(OH)xO3-x and O-O species that coexist in the BONNT catalyst are demonstrated as active centers, which differs from the B(OH)xO3-x one in BNNTs. Based on catalytic results, propane and oxygen alternate treatment experiments, and theoretical calculations, the O-O center is more favorable for producing both propylene (C3=) and ethylene (C2=), which experiences a dehydration pathway and two possible reaction paths with a lower energy barrier to yield olefins, while B(OH)xO3-x is mainly responsible for producing few C3=.

9.
J Colloid Interface Sci ; 610: 527-537, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34863545

RESUMO

The polysulfides shuttling and slow redox kinetics of sulfur-based cathodes have severely hindered the commercialization of lithium-sulfur (Li-S) batteries. Herein, distinctive three-dimensional microspheres composed of boron nitride (BN) nanosheets and reduced graphene oxide (rGO) were applied to act as efficient sulfur cathode hosts for the first time using in a spray-drying process. Using this construction, the robust microsphere structure could shorten ion diffusion pathways and supply sufficient spaces to alleviate the volumetric expansion of sulfur during lithiation. Besides, the synergistic effect between BN and rGO significantly enhanced polysulfides adsorption capability and accelerated their conversion, verified by the density functional theory (DFT) calculations and adsorption experiments. Consequently, the S-BN@rGO cathode could manifest the high initial capacity (1137 mAh g-1 at 0.2 C) and remarkable cycling/stability performance (572 mAh g-1 at 1 C after 500 cycles). These results shed light on a design concept of high-performance sulfur cathode host materials.

10.
ACS Appl Mater Interfaces ; 13(2): 2853-2867, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33412856

RESUMO

In the development of hexagonal boron nitride (h-BN)-based polymeric composites with high thermal conductivity, it is always challenging to achieve a dense filling of h-BN fillers to form a desired high-density thermal transfer network. Here, a series of boron nitride nanosheets (BNNSs)/epoxy resin (EP) bulk composites filled with ultrahigh BNNSs content (65-95 wt %) is successfully constructed through a well-designed mechanical-balling prereaction combined with a general pressure molding method. By means of this method, the highly filled BNNSs fillers are uniformly dispersed and strongly bonded with EP within the composites. As a result, the densely BNNSs-filled composites can exhibit multiple performances. They have excellent mechanical properties, and their maximum compression strength is 30-97 MPa. For a BNNSs/EP composite with filling ultrahigh BNNSs fraction up to 90 wt %, its highly in-plane thermal conductivities (TC) are 6.7 ± 0.1 W m-1 K-1 (at 25 °C) to 8.7 ± 0.2 W m-1 K-1 (200 °C), respectively. In addition, the minimum coefficient of thermal expansion of BNNSs/EP composites is 4.5 ± 1.3 ppm/°C (only ∼4% of that of the neat EP), while their dielectric constants are basically located between 3-4 along with their dielectric loss tangent values exceptionally <0.3 in the ultrahigh frequency range of 12-40 GHz. Additionally, these BNNSs/EP composites exhibit remarkable cycle stability in heat transfer during heating and cooling processes because of their structural robustness. Thus, this type of densely BNNSs-filled BNNSs/EP composite would have great potential for further practical thermal management fields.

11.
Chemistry ; 26(72): 17567-17573, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-32965742

RESUMO

Lithium-sulfur (Li-S) batteries are one of the most promising high-energy-density storage systems. However, serious capacity attenuation and poor cycling stability induced by the shuttle effect of polysulfide intermediates can impede the practical application of Li-S batteries. Herein we report a novel sulfur cathode by intertwining multi-walled carbon nanotubes (CNTs) and porous boron nitride fibers (BNFs) for the subsequent loading of sulfur. This structural design enables trapping of active sulfur and serves to localize the soluble polysulfide within the cathode region, leading to low active material loss. Compared with CNTs/S, CNTs/BNFs/S cathodes deliver a high initial capacity of 1222 mAh g-1 at 0.1 C. Upon increasing the current density to 4 C, the cell retained a capacity of 482 mAh g-1 after 500 cycles with a capacity decay of only 0.044 % per cycle. The design of CNTs/BNFs/S gives new insight on how to optimize cathodes for Li-S batteries.

12.
Inorg Chem ; 59(2): 1234-1241, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31880926

RESUMO

All-inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have great potential for various applications due to their excellent photoluminescence properties. However, poor stability under long-term storage hinders their applications. Herein we report the utilization of porous boron nitride nanofibers (BNNFs) as a promising carrier for anchoring of CsPbBr3 QDs. Due to the good dispersion and immobilization of CsPbBr3 QDs, the resulting CsPbBr3/BNNF composites show excellent photostability and superior long-term storage stability in an air environment. Moreover, the CsPbBr3/BNNF composites exhibit an interesting ammonia-responsive behavior: i.e., a distinct decrease in photoluminescence intensity upon exposure to ammonia gas and the subsequent photoluminescence recovery after post-treatment in nitrogen gas. Even after treatment with ammonia gas for 3 h, the composites can still be recovered under nitrogen gas treatment. The fast response, reversibility, and stability of CsPbBr3/BNNF composites in the presence of ammonia gas could inspire a broader range of applications.

13.
Nanomicro Lett ; 10(4): 75, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30464940

RESUMO

The hydrogen evolution reaction (HER) is a half-cell reaction in water electrolysis for producing hydrogen gas. In industrial water electrolysis, the HER is often conducted in alkaline media to achieve higher stability of the electrode materials. However, the kinetics of the HER in alkaline medium is slow relative to that in acid because of the low concentration of protons in the former. Under the latter conditions, the entire HER process will require additional effort to obtain protons by water dissociation near or on the catalyst surface. Heterostructured catalysts, with fascinating synergistic effects derived from their heterogeneous interfaces, can provide multiple functional sites for the overall reaction process. At present, the activity of the most active known heterostructured catalysts surpasses (platinum-based heterostructures) or approaches (noble-metal-free heterostructures) that of the commercial Pt/C catalyst under alkaline conditions, demonstrating an infusive potential to break through the bottlenecks. This review summarizes the most representative and recent heterostructured HER catalysts for alkaline medium. The basics and principles of the HER under alkaline conditions are first introduced, followed by a discussion of the latest advances in heterostructured catalysts with/without noble-metal-based heterostructures. Special focus is placed on approaches for enhancing the reaction rate by accelerating the Volmer step. This review aims to provide an overview of the current developments in alkaline HER catalysts, as well as the design principles for the future development of heterostructured nano- or micro-sized electrocatalysts.

14.
ACS Appl Mater Interfaces ; 10(43): 37046-37056, 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-30295458

RESUMO

Heteroatom-doped three-dimensional (3D) carbon fiber networks have attracted immense interest because of their extensive applications in energy-storage devices. However, their practical production and usage remain a great challenge because of the costly and complex synthetic procedures. In this work, flexible B, N, and O heteroatom-doped 3D interconnected carbon microfiber networks (BNOCs) with controllable pore sizes and elemental contents were successfully synthesized via a facile one-step "chemical vapor etching and doping" method using cellulose-made paper, the most abundant and cost-effective biomass, as an original network-frame precursor. Under a rational design, the BNOCs exhibited interconnected microfiber-network structure as expressways for electron transport, spacious accessible surface area for charge accumulation, abundant mesopores and macropores for rapid inner-pore ion diffusion, and lots of functional groups for additional pseudocapacitance. Being applied as binder-free electrodes for supercapacitors, BNOC-based supercapacitors not only revealed a high specific capacitance of 357 F g-1, a high capacitance retention of 150 F g-1 at 200 A g-1, a high energy density of 12.4 W h kg-1, and a maximum power density of 300.6 kW kg-1 with an aqueous electrolyte in two-electrode configuration but also exhibited a high specific capacitance of up to 242.4 F g-1 in an all-solid-state supercapacitor.

15.
ACS Nano ; 11(1): 558-568, 2017 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-27959509

RESUMO

Construction of cellular architectures has been expected to enhance materials' mechanical tolerance and to stimulate and broaden their efficient utilizations in many potential fields. However, hitherto, there have been rather scarce developments in boron nitride (BN)-type cellular architectures because of well-known difficulties in the syntheses of BN-based structures. Herein, cellular-network multifunctional foams made of interconnective nanotubular hexagonal BN (h-BN) architectures are developed using carbothermal reduction-assisted in situ chemical vapor deposition conversion from N-doped tubular graphitic cellular foams. These ultralight, chemically inert, thermally stable, and robust-integrity (supporting about 25,000 times of their own weight) three-dimensional-BN foams exhibit a 98.5% porosity, remarkable shape recovery (even after cycling compressions with 90% deformations), excellent resistance to water intrusion, thermal diffusion stability, and high strength and stiffness. They remarkably reduce the coefficient of thermal expansion and dielectric constant of polymeric poly(methyl methacrylate) composites, greatly contribute to their thermal conductivity improvement, and effectively limit polymeric composite softening at elevated temperatures. The foams also demonstrate high-capacity adsorption-separation and removal ability for a wide range of oils and organic chemicals in oil/water systems and reliable recovery under their cycling usage as organic adsorbers. These created multifunctional foams should be valuable in many high-end practical applications.

16.
Adv Mater ; 29(6)2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27911034

RESUMO

A novel carbon structure, highly branched homogeneous-N-doped graphitic (BNG) tubular foam, is designed via a novel N, N-dimethylformamide (DMF)-mediated chemical vapor deposition method. More structural defects are found at the branched portions as compared with the flat tube domains providing abundant active sites and spacious reservoirs for Li+ storage. An individual BNG branch nanobattery is constructed and tested using in situ transmission electron microscopy and the lithiation process is directly visualized in real time.

17.
Int J Mol Sci ; 17(4): 531, 2016 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-27070592

RESUMO

Although dasatinib is effective in most imatinib mesylate (IMT)-resistant chronic myeloid leukemia (CML) patients, the underlying mechanism of its effectiveness in eliminating imatinib-resistant cells is only partially understood. This study investigated the effects of dasatinib on signaling mechanisms driving-resistance in imatinib-resistant CML cell line K562 (K562R(IMT)). Compared with K562 control cells, exsomal release, the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/ mammalian target of rapamycin (mTOR) signaling and autophagic activity were increased significantly in K562R(IMT) cells and mTOR-independent beclin-1/Vps34 signaling was shown to be involved in exosomal release in these cells. We found that Notch1 activation-mediated reduction of phosphatase and tensin homolog (PTEN) was responsible for the increased Akt/mTOR activities in K562R(IMT) cells and treatment with Notch1 γ-secretase inhibitor prevented activation of Akt/mTOR. In addition, suppression of mTOR activity by rapamycin decreased the level of activity of p70S6K, induced upregulation of p53 and caspase 3, and led to increase of apoptosis in K562R(IMT) cells. Inhibition of autophagy by spautin-1 or beclin-1 knockdown decreased exosomal release, but did not affect apoptosis in K562R(IMT) cells. In summary, in K562R(IMT) cells dasatinib promoted apoptosis through downregulation of Akt/mTOR activities, while preventing exosomal release and inhibiting autophagy by downregulating expression of beclin-1 and Vps34. Our findings reveal distinct dasatinib-induced mechanisms of apoptotic response and exosomal release in imatinib-resistant CML cells.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Dasatinibe/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Exossomos/efeitos dos fármacos , Mesilato de Imatinib/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Autofagia/efeitos dos fármacos , Linhagem Celular Tumoral , Exossomos/metabolismo , Exossomos/patologia , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo
18.
Nanomedicine (Lond) ; 11(5): 447-63, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26891593

RESUMO

AIM: To evaluate the response of cells to boron nitride nanotubes (BNNTs) carrying fluorescent probes or drugs in their inner channel by assessment of the cellular localization of the fluorescent cargo, evaluation of the in vitro release and biological activity of a drug (curcumin) loaded in BNNTs. METHODS: Cells treated with curcumin-loaded BNNTs and stimulated with lipopolysaccharide were assessed for nitric oxide release and stimulation of IL-6 and TNF-α. The cellular trafficking of two cell-permeant dyes and a non-cell-permeant dye loaded within BNNTs was imaged. RESULTS: BNNTs loaded with up to 13 wt% fluorophores were internalized by cells and controlled release of curcumin triggered cellular pathways associated with the known anti-inflammatory effects of the drug. CONCLUSION: The overall findings indicate that BNNTs can function as nanocarriers of biologically relevant probes/drugs allowing one to examine/control their local intracellular localization and biochemical effects, leading the way to applications as intracellular nanosensors.


Assuntos
Curcumina/administração & dosagem , Sistemas de Liberação de Medicamentos , Inflamação/tratamento farmacológico , Nanotubos/química , Compostos de Boro/administração & dosagem , Compostos de Boro/química , Curcumina/química , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Fluorescência , Humanos , Inflamação/patologia , Interleucina-6/biossíntese , Óxido Nítrico/biossíntese , Fator de Necrose Tumoral alfa/biossíntese
19.
Nanoscale ; 7(45): 18992-7, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26511400

RESUMO

How to concentrate target molecules on the surface of a SERS substrate is a key problem in the practical application of SERS. Herein, we designed for the first time a pollutant capturing surface enhanced Raman spectroscopy (SERS) substrate, namely porous BN microfibers uniformly decorated with Ag nanoparticles, in which the BN microfibers adsorb pollutants, while the Ag nanoparticles provide SERS activity. This SERS substrate captures pollutants from an aqueous solution completely and accumulates them all on its surface without introducing noise signals. The pores of BN protect the silver particles from aggregation which makes BN/Ag a stable and recyclable SERS substrate. What's more, while the dyes are thoroughly concentrated from a diluted solution, the SERS detection limit is easily enhanced, from 10(-6) M to 10(-9) M.


Assuntos
Compostos de Boro/química , Poluentes Ambientais/análise , Nanopartículas Metálicas/química , Prata/química , Análise Espectral Raman/métodos , Adsorção , Porosidade
20.
Mol Med Rep ; 12(3): 4462-4468, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26081986

RESUMO

The high-mobility group box 1 (HMGB1) protein is a DNA-binding nuclear protein, which is overexpressed in leukemia cells. Cordycepin is characterized by strong antileukemic properties and is regarded as an effective natural compound for leukemia therapy. The aim of the present study was to investigate the impact of HMGB1 knockdown and cordycepin treatment on proliferation, apoptosis, reactive oxygen species (ROS) levels and adhesion of K562 human chronic myeloid leukemia cells. The Cell Counting kit­8 assay was used to determine the proliferation of K562 cells. The cell cycle and apoptosis of K562 cells was determined using flow cytometric analysis. In addition, a cell adhesion assay was performed. Western blotting was used to determine the protein expression of cyclooxygenase 2, Bax, receptor for advanced glycation end-products and Bcl­2. The data collected demonstrated that HMGB1 knockdown combined with cordycepin treatment had significant anti­proliferative and pro­apoptotic effects. In addition, it increased the ROS levels and reduced the adhesion of K562 cells. It was also identified that HMGB1 knockdown had synergistic effects with cordycepin, which aided in accelerating apoptosis, and inhibiting proliferation and adhesion in chronic myeloid leukemia cells. These results indicated that HMGB1 may be used as a potential therapeutic target, with cordycepin having potential as an auxiliary drug. Therefore, it is suggested that HMGB1 knockdown and corycepin treatement may present a promising therapeutic strategy for leukemia.


Assuntos
Antineoplásicos/farmacologia , Desoxiadenosinas/farmacologia , Proteína HMGB1/genética , Apoptose , Adesão Celular/efeitos dos fármacos , Proliferação de Células , Terapia Combinada , Ciclo-Oxigenase 2/metabolismo , Técnicas de Silenciamento de Genes , Células HEK293 , Proteína HMGB1/metabolismo , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/terapia , RNA Interferente Pequeno/genética , Espécies Reativas de Oxigênio/metabolismo , Receptor para Produtos Finais de Glicação Avançada/metabolismo
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