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1.
Int J Biol Macromol ; 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31593715

RESUMO

Osteoinductive bone filling biomaterials are in high demand for effective bone defect reconstruction. In this study, we aimed to design both organic and inorganic substances containing strontium-doped hydroxyapatite/silk fibroin (SrHA/SF) biocomposite nanospheres as an osteoinductive bone defect-filling biomaterial. SrHA/SF nanospheres were prepared with different concentration of Sr using ultrasonic coprecipitation method. The nanospheres were characterized using XRD, FTIR, SEM, TEM, ICP-AES and TGA. Solid and dense SrHA/SF nanospheres with 500-700 nm size and rough surfaces were synthesized successfully. Higher crystallinity and HA/SF phase were observed with the increase in Sr-concentration. The doping of different concentration of Sr did not affect the size and surface characteristics of the nanospheres. ICP-AES data showed that Sr/Ca ratio in SrHA/SF is very close to the nominal value. Nanospheres with higher concentration of Sr did not negatively affect the biocompatibility, but enhanced viability of mesenchymal stem cells (MSCs). Moreover, SrHA/SF nanospheres showed higher osteogenic differentiation potential compared to HA/SF nanospheres as indicated by the results from ALP staining, ALP activity, and Runx2, Alp, Col-1 and Opn gene expression assay in MSCs culture. Our findings suggest this novel design of biocompatible and osteoinductive SrHA/SF biocomposite nanospheres as a potential bone defect-filling biomaterial for bone regenerative applications.

2.
Biofactors ; 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31580525

RESUMO

Tumor energy metabolism and angiogenesis play significant roles in tumor genesis and development, while the effect of the tumor microenvironment (TME), which tumors rely on, is always ignored. In this research, we cocultured bladder cancer (BC) T24 cells with tumor-associated human umbilical vein endothelial cells (HUVECs) under normoxic and hypoxic conditions and detected proliferation, migration, oxidative phosphorylation (OXPHOS) and glycolysis to reveal the energy metabolism characteristics and their effect on cell biological behaviors (CBBs) in the TME. Compared with single-cultured cells, both cocultured T24 cells and HUVECs showed poor proliferation and migration in hypoxic environment, and OXPHOS was activated in cocultured T24 cells but weakened in cocultured HUVECs. However, in normoxic environment, cocultured T24 cells grew much faster while cocultured HUVECs grew slower compared with single-cultured cells. Additionally, glycolysis played a crucial role in energy metabolism and was inhibited in cocultured T24 cells but activated in cocultured HUVECs. In normoxic TME, OXPHOS take main responsibility of energy metabolism. T24 cells exhibited increased proliferation and migration with HUVECs support. In hypoxic TME, glycolysis may be the primary energy supply pathway. T24 cells then exhibit suppressed proliferation and migration, while HUVECs tend to promote angiogenesis to adapt to the harsh TME.

3.
Viruses ; 11(10)2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31569752

RESUMO

Influenza viruses are important pathogens causing respiratory disease in humans and animals. In contrast to influenza A virus (IAV) that can infect a wide range of animal species, other influenza viruses, including influenza B virus (IBV), influenza C virus (ICV), and influenza D virus (IDV) have a limited host range. Swine can be infected with all four different genera of influenza viruses. IAV infection of pigs causes the well-known swine influenza that poses significant threats to human and animal health. However, influenza virus infection of pigs with IBV, ICV, and IDV are not well-characterized. Herein, we compared pathogenicity of IBV and IDV using intratracheal and intranasal infection of pigs, which are IAV seropositive, and commingled naïve pigs with the infected animals to determine their transmissibility. Both viruses caused fever and some lung lesions, replicated in the lungs of infected pigs, but only IDV transmitted to the contact animals. Although IBV and IDV displayed differing levels of replication in the respiratory tract of infected pigs, no significant differences in pathogenicity of both viruses were observed. These results indicate that both IBV and IDV can replicate, and are pathogenic in pigs.

4.
J Agric Food Chem ; 67(38): 10660-10666, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31479263

RESUMO

Two new indolyl diketopiperazines, gartryprostatins A and B (1 and 2), with an unusual 2,3-furan-fused pyrano[2,3-g]pyrrolo[1″,2″:4',5']pyrazino[1',2':1,5]pyrrolo[2,3-b]indole nucleus, along with a new naturally occurring compound (gartryprostatin C, 3) were isolated from the solid culture of Aspergillus sp. GZWMJZ-258, an endophyte from Garcinia multiflora (Guttiferae). The structures of compounds 1-3 were determined by nuclear magnetic resonance, mass spectrometry, Marfey's analysis of amino acids, and chemical calculation. Compounds 1-3 displayed selective inhibition on human FLT3-ITD mutant AML cell line, MV4-11, with IC50 values of 7.2, 10.0, and 0.22 µM, respectively.


Assuntos
Aspergillus/química , Dicetopiperazinas/farmacologia , Endófitos/química , Garcinia/microbiologia , Plantas Medicinais/microbiologia , Aspergillus/genética , Aspergillus/isolamento & purificação , Aspergillus/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dicetopiperazinas/química , Dicetopiperazinas/metabolismo , Endófitos/genética , Endófitos/isolamento & purificação , Endófitos/metabolismo , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular
5.
J Physiol ; 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31506936

RESUMO

KEY POINTS: There is a close relationship between skeletal muscle physiology and Ca2+ /calmodulin (CaM) signalling. Despite the effects of Ca2+ /CaM signalling on immune and inflammatory responses having been extensively explored, few studies have investigated the role of CaM pathway activation on the post-injury muscle inflammatory response. In this study, we investigated the role of CaM-dependent signalling in muscle inflammation in cardiotoxin induced myoinjuries in mice. The Ca2+ /calmodulin-dependent protein kinase II (CaMII), Ca2+ /calmodulin-dependent protein kinase IV (CaMKIV), and nuclear factor of activated T cells (NFAT) pathways are likely to be simultaneously activated in muscle cells and in infiltrating lymphocytes and to regulate the immune behaviours of myofibres in an inflammatory environment, and these pathways ultimately affect the outcome of muscle inflammation. ABSTRACT: Calcium/calmodulin (Ca2+ /CaM) signalling is essential for immune and inflammatory responses in tissues. However, it is unclear if Ca2+ /CaM signalling interferes with muscle inflammation. Here we investigated the roles of CaM-dependent signalling in muscle inflammation in mice that had acute myoinjuries in the tibialis anterior muscle induced by intramuscular cardiotoxin (CTX) injections and received intraperitoneal injections of either the CaM inhibitor calmidazolium chloride (CCL) or CaM agonist calcium-like peptide 1 (CALP1). Multiple inflammatory parameters, including muscle autoantigens and toll-like receptors, mononuclear cell infiltration, cytokines and chemokines associated with peripheral muscle inflammation, were examined after the injury and treatment. CALP1 treatment enhanced intramuscular infiltration of monocytes/macrophages into the damaged tibialis anterior muscle and up-regulated mRNA and protein levels of muscle autoantigens (Mi-2, HARS and Ku70) and Toll-like receptor 3 (TLR3), and mRNA levels of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), Monocyte chemoattractant protein-1 (MCP1), Monocyte chemoattractant protein-3 (MCP3) and Macrophage inflammatory protein-1(MIP-1α) in damaged muscle. In contrast, CCL treatment decreased the intramuscular cell infiltration and mRNA levels of the inflammatory mediators. After CALP1 treatment, a substantial up-regulation in Ca2+ /calmodulin-dependent protein kinase II (CaMKII), Ca2+ /calmodulin-dependent protein kinase IV (CaMKIV) and nuclear factor of activated T cells (NFAT) activity was detected in CD45+ cells isolated from the damaged muscle. More pro-inflammatory F4/80+ Ly-6C+ cells were detected in CD45-gated cells after CALP1 treatment than in those after CCL treatment or no treatment. Consistently, in interferon-γ-stimulated cultured myoblasts and myotubes, CALP1 treatment up-regulated the activities of CaMKII, CaMKIV and NFAT, and levels of class I/II major histocompatibility complexes (MHC-I/II) and TLR3. Our findings demonstrated that CaM-dependent signalling pathways mediate the injury-induced acute muscle inflammatory response.

6.
Artigo em Inglês | MEDLINE | ID: mdl-31535447

RESUMO

The electrocatalytic urea oxidation reaction (UOR) provides more economic electrons than water oxidation for various renewable energy-related systems owing to its lower thermodynamic barriers. However, it is limited by sluggish reaction kinetics, especially by CO2 desorption steps, masking its energetic advantage compared with water oxidation. Now, a lattice-oxygen-involved UOR mechanism on Ni4+ active sites is reported that has significantly faster reaction kinetics than the conventional UOR mechanisms. Combined DFT, 18 O isotope-labeling mass spectrometry, and in situ IR spectroscopy show that lattice oxygen is directly involved in transforming *CO to CO2 and accelerating the UOR rate. The resultant Ni4+ catalyst on a glassy carbon electrode exhibits a high current density (264 mA cm-2 at 1.6 V versus RHE), outperforming the state-of-the-art catalysts, and the turnover frequency of Ni4+ active sites towards UOR is 5 times higher than that of Ni3+ active sites.

7.
Dalton Trans ; 48(36): 13589-13598, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31478049

RESUMO

Silver corrolates are attractive compounds from both practical and theoretical points of view. Indeed, they play a key role in peripheral functionalization reactions occurring at the macrocycle, enabling high-yield and regioselective group insertions useful to further elaborate the molecular skeleton. In parallel, the Janus innocent or noninnocent behavior of the corrole ligand in these complexes makes their description particularly challenging. Herein, we report properties for a series of silver 3,17-disubstituted triarylcorrole complexes with various functionalities (halogens or different phenylethynyl units) that deeply affect the electron density in the macrocyclic ligand, with obvious repercussions on the observed spectral characteristics. The compounds were obtained in yields of 54-92% by applying the Stille coupling reaction with the appropriate tributylethynyl stannane. Among the complexes prepared was a derivative bearing two terminal acetylenic units which opens the way to "click" reactions for new corrole-based architectures. This corrole was structurally characterized by single crystal X-ray crystallography. The addition of substituted ethynyl groups resulted in red-shifts of the electronic absorption spectra, the largest of which was observed for the compound with two ß-NO2-Ph-C[triple bond, length as m-dash]C substituents. The remarkable influence of the NO2 groups on the electron density of this macrocycle was further demonstrated by electrochemical measurements, where an easier reduction of this complex derivative was observed as compared to the others. DFT calculations showed full delocalization over the entire p-nitrophenylethynyl unit of 5, largely affecting orbital distributions and the corresponding electronic absorptions. Although a variation of the ß-substituents dramatically modifies the Soret- and Q-band positions towards lower energies for all the examined complexes, the saddling of the macrocycle resulting from functionalization is only moderate. The collected results suggest the description of these compounds as AgIII-corrolate3-, a metallocorrole with an innocent macrocyclic ligand.

8.
Nan Fang Yi Ke Da Xue Xue Bao ; 39(8): 944-949, 2019 Aug 30.
Artigo em Chinês | MEDLINE | ID: mdl-31511215

RESUMO

OBJECTIVE: To verify whether dexmedetomidine hydrochloride (Dex) alleviates renal ischemia-reperfusion (IR) injury in diabetic rats by increasing the expression of hypoxia inducible factor-1α (HIF-1α). METHODS: A rat model of type 2 diabetes mellitus was established by high-fat diet and streptozotocin injection. The rats were subjected to daily intragastric administration of 0.05 mg/kg digoxin for 7 consecutive days and intraperitoneal injection of Dex 2 h before renal IR injury induced by ligation of the bilateral renal arteries for 60 min followed by reperfusion for 120 min. After reperfusion, blood samples were taken for detection of serum creatinine (Scr) and urea nitrogen (BUN) levels. Western blotting was used to detect the expression of HIF-1α, cleaved caspase-3, Bcl-2, and Bax in the renal tissues; the expression of the HIF-1α, p-eNOS, and eNOS were detected using ELISA. The percentage of apoptotic glomerular cells was assessed using TUNEL assay. RESULTS: The levels of Scr, BUN, HIF-1α, p-eNOS, and eNOS and the percentage of apoptotic cells in both normal and diabetic rats increased significantly after renal IR injury (P < 0.05). The expressions of Scr, BUN, p-eNOS, and eNOS decreased while HIF-1α expression increased significantly in Dex-treated rats with renal IR injury (P < 0.05). Compared with the non-diabetic rats, the diabetic rats showed more obvious increase in the expressions of Scr, BUN, p-eNOS, and eNOS following renal IR injury. In the diabetic rats with renal IR injury, Dex treatment prior to the injury significantly lowered the expressions of Scr, BUN, p-eNOS, eNOS, cleaved caspase-3, and Bax, decreased the percentage of apoptotic cells, and increased the levels of HIF-1a and Bcl-2 (P < 0.05). Digoxin treatment significantly antagonized the effects of Dex in the diabetic rats with renal IR injury by increasing the expressions of cleaved caspase-3 and Bax, promoting glomerular cell apoptosis, and decreasing renal expressions of HIF-1 and Bcl-2 (P < 0.05). CONCLUSIONS: Dex alleviates renal IR injury in diabetic rats probably by inhibiting renal expression of HIF-1α and glomerular cell apoptosis.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Traumatismo por Reperfusão , Animais , Dexmedetomidina , Hipóxia , Subunidade alfa do Fator 1 Induzível por Hipóxia , Rim , Ratos , Ratos Sprague-Dawley
9.
Chemosphere ; 235: 1089-1096, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561299

RESUMO

WWTPs may be one of the important ways for MPs to enter surface water. In the present study, the influent and effluent from eleven WWTPs in Changzhou were collected and analyzed. At the same time, the abundance, size, color, and shape of MPs in influent and effluent were investigated. The average abundance of MPs in the influent and effluent were 196.00 ±â€¯11.89 n/L and 9.04 ±â€¯1.12 n/L respectively, and the MPs removal efficiency of eleven WWTPs was almost over 90% in which it could be up to 97.15%. MPs were divided into four particle size based on abundance changes, and the size of MPs with the highest abundant was mainly concentrated at 0.1-0.5 mm. Among these MPs, fibers were the main shape in wastewater, followed by fragments, flakes, spheres and films. The colors of MPs in wastewater were various and 14 types of plastics were detected from wastewater using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Moreover, Rayon and PET were the dominant polymer types in eleven WWTPs. The research results provided basic data for the research and supervision of MPs pollution in WWTPs.

10.
PLoS One ; 14(9): e0223228, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31557269

RESUMO

Chloroplast plays an important role in the plant life cycle. However, the details of its development remain elusive in rice. In this study, we report the fine-mapping of a novel rice gene wpb1 (white panicle branch 1), which affects chloroplast biogenesis, from a tropical japonica variety that results in an albino panicle branches at and after the heading stage. The wpb1 variety was crossed with Nipponbare to generate the F2 and BC1F2 populations. Green and white panicle branch phenotypes with a 3:1 segregation ratio was observed in the F2 population. Bulked segregant analysis (BSA) based on whole genome resequencing was conducted to determine the wpb1 locus. A candidate interval spanning from 11.35 to 23.79M (physical position) on chromosome 1 was identified. The results of BSA analysis were verified by a 40K rice SNP-array using the BC1F2 population. A large-scale F2 population was used to pinpoint wpb1, and the locus was further narrowed down to a 95-kb interval. Furthermore, our results showed that the expression levels of the majority of the genes involved in Chl biosynthesis, photosynthesis and chloroplast development were remarkably affected in wpb1 variety and in F2 plants with a white panicle branch phenotype. In line with the results mentioned above, anatomical structural examination and chlorophyll (Chl) content measurement suggested that wpb1 might play an important role in the regulation of chloroplast development. Further cloning and functional characterization of the wpb1 gene will shed light on the molecular mechanism underlying chloroplast development in rice.

11.
Proc Natl Acad Sci U S A ; 116(40): 20151-20157, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31481617

RESUMO

The sense of one's own body is a pillar of self-consciousness and could be investigated by inducing human illusions of artificial objects as part of the self. Here, we present a nonhuman primate version of a rubber-hand illusion that allowed us to determine its computational and neuronal mechanisms. We implemented a video-based system in a reaching task in monkeys and combined a casual inference model to establish an objective and quantitative signature for the monkey's body representation. Similar to humans, monkeys were more likely to perceive an external object as part of the self when the dynamics (spatial disparity) and the features (shape and structure) of visual (V) input was closer to proprioceptive (P) signals. Neural signals in the monkey's premotor cortex reflected the strength of illusion and the likelihood of misattributing the illusory hand to oneself, thus, revealing a cortical representation of body ownership.

12.
Org Lett ; 21(19): 8075-8079, 2019 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-31550167

RESUMO

A bioinspired, Me2AlSEt-promoted domino Dieckmann cyclization via an 8-membered ring intermediate to construct bicyclo[3.3.1]nonanes was developed, and the divergent syntheses of nine complex polycyclic polyprenylated acylphloroglucinols were achieved. This novel domino cyclization tolerates a series of congested substrates, providing a very efficient way to construct diverse polycyclic structures. The selectivity and the advantages of the domino cyclization were studied. Moreover, the structure-activity relationship study leads to the identification of three simplified potent antitumor agents.

13.
Aging (Albany NY) ; 11(18): 7847-7858, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31548436

RESUMO

Klotho beta (KLB) mediates binding of fibroblast growth factor (FGF) 21 to the FGF receptor (FGFR). FGF21-KLB-FGFR signaling regulates multiple metabolic systems in the liver, and we hypothesized that FGF21, KLB and FGFR single-nucleotide polymorphisms (SNPs) are involved in hepatic lipid accumulation. The SNPs were detected in 1688 individuals divided into four groups: non-obese without non-alcoholic fatty liver disease (NAFLD), obese without NAFLD, non-obese with NAFLD, and obese with NAFLD. The A-allele of KLB SNP rs7670903 correlated with higher body mass index (P = 0.0005), and the A-allele frequency was higher in the obese than non-obese group (P = 0.003). The G-allele frequency of KLB rs7674434 and T-allele frequency of rs12152703 were higher in the obese with NAFLD than obese without NAFLD group (P = 0.004 and P = 0.006), but the genotype distribution between two non-obese groups did not differ. KLB rs7674434 and rs12152703 had associations with alanine aminotransferase (ALT) (P = 0.03 and P = 0.04, respectively) and gamma-glutamyltransferase (P = 0.03 and P = 0.02, respectively) levels in all subjects, but the associations were especially strong with ALT in the NAFLD group (P = 0.005 and P = 0.008, respectively). These findings suggest that KLB SNPs are related to obesity and hepatic inflammation and that they may be involved in the pathogenesis of NAFLD.

14.
Colloids Surf B Biointerfaces ; 183: 110385, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31408781

RESUMO

Polypeptide carriers have a good cell compatibility, rich functionality, and facile synthesis and modification, make them promising materials as siRNA vectors. Phenylalanine dipeptide (FF) has been previously assessed as an siRNA vector and showed to have two major drawbacks, namely poor water solubility and poor serum stability. Herein, the FF backbone was modified by ligating a PEG-Arg-Ala (PEG-RA) sequence at the N-terminus to increase its hydrophilicity and serum stability. Arg is a typical amino acid in the cell penetrating peptide, which can increase the efficiency of cell internalization. Ala acts as a spacer to avoid steric hindrance. The target sequence PEG-RAFF was synthesized by a solid phase peptide synthesis. The morphology, particle size, and siRNA ratio were assessed by SEM, TEM, DLS, and gel electrophoresis. Further, MCF-7 cells were used as a model and survivin-siRNA as a passenger to assess cell internalization, inhibition of gene expression rate, and apoptosis rate using confocal microscopy, real-time PCR, and flow cytometry. At a concentration of 1 mg/mL, PEG-RAFF took the form of nanovesicles with a diameter of 154.74 ±â€¯14.36 nm. The optimal PEG-RAFF to siRNA ratio was N/P = 100:1. Compared with the control group, the red fluorescence of TAMRA(Carboxytetramethylrhodamine, Red fluorescence)-siRNA transfected into cells was clearly visible in the confocal microscope image. The inhibition rate of survivin was 67.99 ±â€¯10.31%, and the apoptotic rate was 16.07%. Therefore, PEG-RAFF has potential as an siRNA carrier in cancer treatment.

15.
Dalton Trans ; 48(34): 13064-13073, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31410436

RESUMO

Conductive graphene accelerates localized corrosion at exposed coating-metal interfaces as a cathode, which impedes its applications in metal protection. Nevertheless, graphene-polymer coatings are still the best option due to the original impermeability and chemical stability once the galvanic coupling is cut. However, it is difficult to guarantee the miscibility when graphene is employed as the nanofiller. Herein, a bi-layered nanocomposite coating with self-healing capability at the functional level that ensures strong interfacial interaction is reported in this work. Unlike previous nanofiller coatings, the coating with the benzotriazole-loaded nanoreservoir intermediate layer structure and poly (vinyl butyral-co-vinyl alcohol-co-vinyl acetate) topcoat was fabricated via the dip-coating and spin-coating technique, respectively. An efficient nanoreservoir with a thickness of 35 nm for corrosion inhibitor delivery was synthesized by a combination of the oil-water stratification method and vacuum loading. Semiempirical models, which have scarcely been reported on corrosion inhibitor release, were blazed to predict the diffusion mechanism. The corrosion resistance was evaluated by electrochemical characterization. With a nanoreservoir loading of 0.25 g/(20 mL ethanol), the bilayer nanocomposite coating not only improved the barrier properties, but also showed self-healing ability for long-term protection. This strategy provides a candidate for the development of graphene-based anticorrosion coatings.

16.
Nanomedicine (Lond) ; 14(16): 2105-2119, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31397219

RESUMO

Aim: To improve the drug delivery to the brain with borneol (Bo)-modified solid lipid nanoparticles (SLNs) of pueraria flavones (PTF) via intranasal administration. Materials & methods: PTF-loaded SLNs were modified with Bo by physical and chemical methods to synthesize PTF-Bo-SA-SLNs and PTF-Bo-SLNs. The prepared SLNs were characterized and their brain delivery effects were evaluated in vitro and in vivo. Results: There was a more pronounced accumulation of PTF-Bo-SA-SLNs in Caco-2 cells. Following intranasal administration, more coumarin-6 was found in the rat brain carried by Bo-SA-SLNs. Brain area under the curve and Cmax of PTF-Bo-SA-SLN were 7.31- and 7.29-times higher than those of PTF-SLN, respectively. Conclusion: PTF-Bo-SA-SLNs are a promising therapeutic carrier for brain disease after intranasal administration.

17.
J Am Chem Soc ; 141(32): 12673-12681, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31381313

RESUMO

Cell surface receptors play a critical role in modulating intracellular signal transduction, making them important drug targets. However, it remains challenging to develop a selective and efficient strategy for regulating receptor function. Herein, we develop a strategy, called bispecific aptamer induced artificial protein-pairing, to selectively regulate receptor function. In this strategy, bispecific aptamer probes act as molecular mediators to bind to both a target receptor protein and a paired protein, which brings the two proteins into close proximity on the living cell membrane. Importantly, the paired proteins work not only as a cancer biomarker for enhancing cell selectivity but also as a blocking assistant to inhibit target receptor function via strong steric hindrance effect. Compared with single-aptamer-mediated regulation, the proposed bispecific aptamer probes afford substantial improvement in selective and efficient regulation of receptor function and downstream signaling pathways. This work offers a versatile methodology to design molecular mediators that can modulate receptor function, thereby providing a new way for developing novel therapeutic drugs.

18.
Artigo em Inglês | MEDLINE | ID: mdl-31403388

RESUMO

A CuO/ZnO nanocomposite for use as photocatalyst was successfully prepared by co-precipitation method. Its chemical and physical properties were evaluated by X-ray diffractometry, scanning electron microscopy, EDS, UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The average particle size of CuO/ZnO composite was found to be around 80 nm. The degradation of oxytetracycline hydrochloride pollutants in marine aquaculture wastewater using ZnO and CuO/ZnO was compared. CuO/ZnO nanocomposite was found to be more efficient than ZnO. The effects of external factors on the photocatalytic efficiency of the nanocomposite were investigated under visible light. Moreover, conditions for the degradation of oxytetracycline hydrochloride using CuO/ZnO nanocomposite were optimized. Based on both, the ability and efficiency of degradation, 10:1 molar ratio of Zn2+/Cu2+ and 0.4 g L-1 nanocomposite, were found to be optimal, using which the average photocatalytic degradation rate of oxytetracycline hydrochloride reached 90%.

19.
J Hazard Mater ; 381: 121019, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31442687

RESUMO

Novel N-doped carbon dots (CDs) were obtained through pyrolysis of ammonium citrate at 180 °C for 1, 2 and 3 h, and their corrosion inhibition effect on Q235 steel in 1 M HCl solution were evaluated through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (Tafel), scanning vibrating electrode technique (SVET) analysis. The changes of corrosion current density and impedance modulus of Q235 steel in inhibitor solutions showed that the as-prepared carbon dots presented a valid protective effect on steel in 1 M HCl solution. Meanwhile, the inhibition efficiency of three carbon dots exceeded 90% at 200 mg/L and the highest inhibitive efficiency was found for the carbon dots prepared at the reaction time of 2 h. The adsorption mechanism of all as-prepared carbon dots complied with the Langmuir adsorption model, containing chemical and physical adsorptions, which was also confirmed by X-ray photoelectronic spectroscopy (XPS) analysis.

20.
J Hazard Mater ; 381: 120956, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445472

RESUMO

Z-scheme heterojunction can efficiently suppress the electron-holes recombination and promote the charges transfer rate, which result in the high photocatalytic performance. Herein, a flower-flake-sphere like CuBi2O4/WO3 hybrid photocatalyst was fabricated via a precursor-guided hydrothermal method. The morphology, structure, composition, chemical and electronic properties of the as-prepared samples were systematically investigated by multiple techniques (XRD, FT-IR, SEM, TEM, XPS, UV-vis, BET, PL, ESR. etc.). Particularly, the 60 wt% CuBi2O4/WO3 nanocomposite exhibited the highest photocatalytic activity for tetracycline (20 mg/L) degradation under simulated solar light irradiation. The rate constant was 0.0179 min-1, which was almost 8 times and 4.5 times higher than that of bulk WO3 and CuBi2O4, respectively. The experimental results confirmed that CuBi2O4 made a direct Z-scheme heterojunction by band alignment with WO3, which are conducive to the efficient charges separation and prolonged carriers lifetime. According to the quenching experiments, •OH and •O2- were testified to be the predominant active species. The electrons accumulated in the CuBi2O4 negative CB and the holes in the WO3 positive VB made significant contribution to the strong redox ability of the CuBi2O4/WO3 nanocomposite. This work provides some deep insights into the design of band-alignment-based Z-scheme heterostuctures, which is also applicable to other catalytic system.

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