Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
ACS Nano ; 2020 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-32203660

RESUMO

Efficient removal of deadly toxicants by blood purification remains predominant in poisoning treatment. Current strategies mainly rely on absorptive scavengers that normally have no selectivity to the adsorbates, which could result poor clinical outcomes to certain toxic species due to the passivity and inaccuracy of the detoxification procedure. Herein, a positive, accurate, and customized detoxification strategy was proposed. Based on the sophisticated molecule design and thoughtful structure analysis of the aimed toxicant paraquat, a supramolecular hunter stationed on red blood cells (RBC) is developed to continuously track paraquat in the blood. In this construct, a Janus dendrimer amphiphile (JDA) molecule was synthesized with the aim of facilely anchoring onto RBC membranes while bridging to load the antidote WP6 that could precisely recognize paraquat. In vitro and in vivo results demonstrate the effective toxicant-hunting and harm-neutralizing capability of the system through a guest-exchange reaction. This strategy provides a different insight in designing scavengers that can actively, precisely, and continuously hunt toxicants through a supramolecular approach.

2.
J Mech Behav Biomed Mater ; 104: 103665, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32174423

RESUMO

Osteochondral (OC) defects usually involve the damage of both the cartilage and its underneath subchondral bone. In recent years, tissue engineering (TE) has become the most promising method that combines scaffolds, growth factors, and cells for the repair of OC defects. An ideal OC scaffold should have a gradient structure to match the hierarchical mechanical properties of natural OC tissue. To satisfy such requirements, 3D printing, e.g., direct ink writing (DIW), has emerged as a technology for precise and customized scaffold fabrication with optimized structures and mechanical properties. In this study, finite element simulations were applied to investigate the effects of pore geometry on the mechanical properties of 3D printed scaffolds. Scaffold specimens with different lay-down angles, filament diameters, inter-filament spacing, and layer overlaps were simulated in compressive loading conditions. The results showed that Young's moduli of scaffolds decreased linearly with increasing scaffold porosity. The orthotropic characteristics increased as the lay-down angle decreased from 90° to 15°. Moreover, gradient transitions within a wide range of strain magnitudes were achieved in a single construct by assembling layers with different lay-down angles. The results provide quantitative relationships between pore geometry and mechanical properties of lattice scaffolds, and demonstrate that the hierarchical mechanical properties of natural OC tissue can be mimicked by tuning the porosity and local lay-down angles in 3D printed scaffolds.

3.
J Control Release ; 321: 483-496, 2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32061623

RESUMO

Chelating Cu from tumors has been verified as an effective and promising strategy for cancer therapy through antiangiogenesis. However, systematic removal Cu by injecting with Cu chelators will result unavoidable side effects, since Cu is indispensable to the body. In this work, a micelle targeting to tumors' newborn vessels based on a polypeptide was developed to co-load DOX and Probe X, which can go through an "OFF-to-ON" procedure to report the Cu+-capture events in vivo in a real-time way by giving near infrared (NIR) fluorescence and photoacoustic signal. By co-delivering antiangiogenesis and chemotherapeutic reagents, the tumor can be significantly suppressed, meanwhile with a low systematic toxicity. Hopefully, this work can offer new insights in designing sophisticated antitumor strategy.

4.
Artigo em Inglês | MEDLINE | ID: mdl-32059595

RESUMO

Taiwan has actively promoted the concept of "successful aging" in recent years. The Executive Yuan drafted the White Paper for Aged Society, which set the primary goal to enable seniors to deal with daily life more independently. Although 'third places' enable seniors to live independently, the third places that Taiwanese seniors like are not well understood. Consequently, by investigating third places, this study will investigate the environment of achieving successful aging and happiness among seniors. This study uses the questionnaire survey, and the data of this study were collected from October to November 2018 in Taichung City Central District. A questionnaire survey was conducted in several administrative agencies and participants were selected by random sampling among the over-55-year-old citizens who were already retired. An estimate of 90% confidence limits with 5% marginal error gave us a sample size of 257. This study finally received 200 efficient samples. The women's top five choices of third places are the traditional market, supermarket, restaurant, daily necessities shop, and coffee shop. The men's top five choices of third places are the traditional market, supermarket, daily necessities shop, restaurant, and a friend's house. For seniors familiar with the concept of third places, the more often they go to third places, the higher happiness they achieve. This result investigates the importance of having awareness of third places for seniors. Therefore, we should encourage them to go to third places and engage in social activities frequently to achieve successful aging.

6.
J Cell Mol Med ; 24(4): 2531-2541, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31930692

RESUMO

Recent research has revealed that cardiac telocytes (CTs) play an important role in cardiac physiopathology and the regeneration of injured myocardium. Recently, we reported that the adult Xenopus tropicalis heart can regenerate perfectly in a nearly scar-free manner after injury via apical resection. However, whether telocytes exist in the X tropicalis heart and are affected in the regeneration of injured X tropicalis myocardium is still unknown. The present ultrastructural and immunofluorescent double staining results clearly showed that CTs exist in the X tropicalis myocardium. CTs in the X tropicalis myocardium were mainly twined around the surface of cardiomyocyte trabeculae and linked via nanocontacts between the ends of the telopodes, forming a three-dimensional network. CTs might play a role in the regeneration of injured myocardium.

7.
ANZ J Surg ; 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31743951

RESUMO

BACKGROUND: Acute cholecystitis (AC) is a surgical condition that is usually managed by emergency surgery. The presence of common bile duct stones (CBDS) in this setting mandates definitive treatment to avoid complications such as cholangitis. The incidence of CBDS in the setting of AC is poorly defined. METHODS: A systematic English literature search was conducted in PubMed, MEDLINE and Embase to determine the incidence of CBDS in patients presenting with AC. Outlier studies identified by funnel plot analysis were excluded and the incidence of CBDS was identified. The mean CBD diameter and liver function test values of patients with AC and CBDS were calculated. RESULTS: Data were extracted from 19 studies representing a total 4057 patients with AC. Routine biliary imaging was not performed in all studies. The pooled incidence of CBDS was 13.7% (95% confidence interval 11.8-15.9). The incidence of unsuspected retained CBDS was 1.1%. Histologically confirmed cases of AC had a similar rate of CBDS compared to those diagnosed clinically. The mean CBD diameter of patients with AC and CBDS was 7.2 mm compared to 5.8 mm without. Liver function test values in the presence of CBDS were more likely to be deranged, with gamma-glutamyltransferase the most sensitive and specific marker for CBDS in the setting of AC. CONCLUSION: CBDS is present in a significant proportion of patients presenting with AC. Routine biliary imaging is advised in all patients presenting with AC where possible.

8.
J Cell Mol Med ; 23(12): 8328-8342, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31612566

RESUMO

Thus far, the cellular and molecular mechanisms related to early (especially within 24 hours after acute myocardial infarct (MI)) exercise-mediated beneficial effects on MI have not yet been thoroughly established. In the present study, we demonstrated that acute MI rats that underwent early moderate exercise training beginning one day after MI showed no increase in mortality and displayed significant improvements in MI healing and ventricular remodelling, including an improvement in cardiac function, a decrease in infarct size, cardiomyocyte apoptosis, cardiac fibrosis and cardiomyocyte hypertrophy, and an increase in myocardial angiogenesis, left ventricular wall thickness and the number of cardiac telocytes in the border zone. Integrated miRNA-mRNA profiling analysis performed by the ingenuity pathway analysis system revealed that the inhibition of the TGFB1 regulatory network, activation of leucocytes and migration of leucocytes into the infarct zone comprise the molecular mechanism underlying early moderate exercise-mediated improvements in cardiac fibrosis and the pathological inflammatory response. The findings of the present study demonstrate that early moderate exercise training beginning one day after MI is safe and leads to significantly enhanced MI healing and ventricular remodelling. Understanding the mechanism behind the positive effects of this early training protocol will help us to further tailor suitable cardiac rehabilitation programmes for humans.

9.
Chemosphere ; 237: 124493, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31398611

RESUMO

Aluminum-based metal-organic framework/sodium alginate-chitosan (Al-MOF/SA-CS) composite beads were synthesized and employed as an adsorbent for the removal of bisphenol A (BPA). Several methods, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), nitrogen adsorption-desorption isotherms and X-ray photoelectron spectroscopy (XPS), were used to characterize the prepared adsorbents. Results demonstrated that the introduction of CS could change the porosity of the beads and the obtained Al-MOF/SA-CS composite beads possessed higher surface area and total pore volume comparing with the beads without CS. Batch experiments were carried out to explore the adsorption performance and the results displayed that the enhanced adsorption capacity was achieved by Al-MOF/SA-CS beads compared to the Al-MOF/SA ones. It is also found from the fitting results that the adsorption process fitted well with the pseudo-second-order kinetics model and followed the Freundlich isotherm model. Importantly, the composite beads could be easily recycled and regenerated by methanol and the adsorption efficiency still maintained as high as 96% even after five cycles. Furthermore, it can be inferred from the experimental results that the π-π stacking, hydrogen bonding and cation-π interaction could be the primary adsorption mechanisms. Considering the high adsorption properties, good water stability, especially easy separation, and excellent recyclability, Al-MOF/SA-CS composite beads could be a promising adsorbent for the removal of BPA from contaminated water.


Assuntos
Alumínio/química , Compostos Benzidrílicos/análise , Fenóis/análise , Poluentes Químicos da Água/análise , Adsorção , Alginatos/química , Quitosana/química , Ligações de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Água , Difração de Raios X
10.
Zhen Ci Yan Jiu ; 44(5): 319-23, 2019 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-31155862

RESUMO

OBJECTIVE: To observe the effect of acupuncture at "Shenshu"(BL23)-"Taixi"(KI3)on the levels of serum uric acid (SUA) and expression of renal urate-anion transporter 1 (URAT1) and organic anion transporter 1 (OAT1) proteins in hyperuricemia (HUA) rats, so as to explore its underlying mechanisms in improving HUA. METHODS: A total of 25 male Wistar rats were divided into 4 groups: control (n=6), HUA model (n=7), BL23-KI3 (n=6) and Ganshu (BL18)-Taichong (LR3, BL18-LR3 in short, n=6). The HUA model was established by gavage of Oteracil Potassium (2 g/kg), once daily for 10 days, then once every other day. For rats of the BL23-KI3 group, BL23 and KI3 were stimulated with filiform needles which were rotated for 10 s at a frequency about 100 r/min, and for rats of the BL18-LR3 group, BL18 and LR3 were stimulated with the same methods to those of the BL23-KI3 group. The treatment of both acupuncture groups was conducted once daily, 6 times a week (except Sundays) for 3 weeks. The contents of SUA and serum creatinine (SCr) were assayed by using an automatic biochemical analyzer. The pathological changes of the right kidney tissue were observed under light microscope after hematoxylin eosin (H.E.) staining, the immunoactivity of URAT1 and OAT1 of the right kidney tissue was determined by immunohistochemistry, and the expression of URAT1 and OAT1 proteins of the left kidney tissue detected by Western blot (WB). RESULTS: After modeling, the content of SUA and the expression of renal URAT1 protein (shown by both immunoactivity and WB) were significantly increased (P<0.01), but that of renal OAT1 protein was obviously decreased in the model group compared with the control group (P<0.01). There was no notably change in the level of SCr in the model group relevant to the control group (P>0.05). Following acupuncture intervention, the SUA content and URAT1 expression in both BL18-LR3 and BL23-KI3 groups were considerably down-regulated (P<0.05, P<0.01), and the expression of OAT1 protein in the BL23-KI3 group (not the BL18-LR3 group) were obviously up-regulated relevant to the model group (P<0.01). The effects of BL23-KI3 were significant superior to those of BL18-LR3 in down-regulating the expression of URAT1 and up-regulating OAT1 protein (P<0.01, P<0.05). CONCLUSION: Acupuncture of "BL23" and "KI3" can effectively down-regulate SUA level in HUA rats, which may be related to its effects in down-regulating the expression of URAT1 and up-regulating the expression of OAT1 in the kidney tissue.


Assuntos
Terapia por Acupuntura , Hiperuricemia , Animais , Ânions , Masculino , Proteína 1 Transportadora de Ânions Orgânicos , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Ácido Úrico
11.
Adv Mater ; 31(6): e1806518, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30549105

RESUMO

Thermal conductivity is a very basic property that determines how fast a material conducts heat, which plays an important and sometimes a dominant role in many fields. However, because materials with phase transitions have been widely used recently, understanding and measuring temperature-dependent thermal conductivity during phase transitions are important and sometimes even questionable. Here, the thermal transport equation is corrected by including heat absorption due to phase transitions to reveal how a phase transition affects the measured thermal conductivity. In addition to the enhanced heat capacity that is well known, it is found that thermal diffusivity can be abnormally lowered from the true value, which is also dependent on the speed of phase transitions. The extraction of the true thermal conductivity requires removing the contributions from both altered heat capacity and thermal diffusivity during phase transitions, which is well demonstrated in four selected kinds of phase transition materials (Cu2 Se, Cu2 S, Ag2 S, and Ag2 Se) in experiment. This study also explains the lowered abnormal thermal diffusivity during phase transitions in other materials and thus provides a novel strategy to engineer thermal conductivity for various applications.

12.
Adv Mater ; 31(4): e1804919, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30422346

RESUMO

Phase transition is a fundamental physical phenomenon that has been widely studied both theoretically and experimentally. According to the Landau theory, the coexistence of high- and low-temperature phases is thermodynamically impossible during a second-order phase transition in a bulk single crystal. Here, the coexistence of two (α and ß) phases in wedge-shaped nanosized single-crystal Cu2 Se over a large temperature range are demonstrated. By considering the surface free-energy difference between the two phases and the shape effect, a thermodynamic model is established, which explicitly explains their coexistence. Intriguingly, it is found that with a precise control of the heating temperature, the phase boundary can be manipulated at atomic level. These discoveries extend the understanding of phase transitions to the nanoscale and shed light on rational manipulation of phase transitions in nanomaterials.

13.
Nat Commun ; 9(1): 2910, 2018 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-30046101

RESUMO

Many superionic mixed ionic-electronic conductors with a liquid-like sublattice have been identified as high efficiency thermoelectric materials, but their applications are limited due to the possibility of decomposition when subjected to high electronic currents and large temperature gradients. Here, through systematically investigating electromigration in copper sulfide/selenide thermoelectric materials, we reveal the mechanism for atom migration and deposition based on a critical chemical potential difference. Then, a strategy for stable use is proposed: constructing a series of electronically conducting, but ion-blocking barriers to reset the chemical potential of such conductors to keep it below the threshold for decomposition, even if it is used with high electric currents and/or large temperature differences. This strategy not only opens the possibility of using such conductors in thermoelectric applications, but may also provide approaches to engineer perovskite photovoltaic materials and the experimental methods may be applicable to understanding dendrite growth in lithium ion batteries.

14.
Bioorg Med Chem ; 26(14): 3866-3874, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-30049586

RESUMO

Acetyl-CoA carboxylase (ACC) catalyzes the rate-determining step in de novo lipogenesis and plays an important role in the regulation of fatty acid oxidation. Therefore, ACC inhibition offers a promising option for intervention in nonalcoholic fatty liver disease (NAFLD), type 2 diabetes (T2DM) and cancer. In this paper, a series of spiropentacylamide derivatives were synthesized and evaluated for their ACC1/2 inhibitory activities and anti-proliferation effects on A549, H1975, HCT116, SW620 and Caco-2 cell lines in vitro. Compound 6o displayed potent ACC1/2 inhibitory activity (ACC1 IC50 = 0.527 µM, ACC2 IC50 = 0.397 µM) and the most potent anti-proliferation activities against A549, H1975, HCT116, SW620 and Caco-2 cell lines, with IC50 values of 1.92 µM, 0.38 µM, 1.22 µM, 2.05 µM and 5.42 µM respectively. Further molecular docking studies revealed that compound 6o maintained hydrogen bonds between the two carbonyls and protein backbone NHs (Glu-B2026 and Gly-B1958). These results indicate that compound 6o is a promising ACC1/2 inhibitor for the potent treatment of cancer.


Assuntos
Acetil-CoA Carboxilase/antagonistas & inibidores , Amidas/farmacologia , Antineoplásicos/farmacologia , Desenho de Drogas , Inibidores Enzimáticos/farmacologia , Compostos de Espiro/farmacologia , Acetil-CoA Carboxilase/metabolismo , Amidas/síntese química , Amidas/química , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Compostos de Espiro/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas
15.
Nat Mater ; 17(7): 652, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29849172

RESUMO

In the version of this Article originally published, the x-axis numbers of Fig. 3d were incorrect; the range should have been 0 to 12 instead of 1 to 13. This has now been corrected.

16.
Opt Express ; 26(10): 12948-12958, 2018 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-29801328

RESUMO

The singular value decomposition ghost imaging (SVDGI) is proposed to enhance the fidelity of computational ghost imaging (GI) by constructing a measurement matrix using singular value decomposition (SVD) transform. After SVD transform on a random matrix, the non-zero elements of singular value matrix are all made equal to 1.0, then the measurement matrix is acquired by inverse SVD transform. Eventually, the original objects can be reconstructed by multiplying the transposition of the matrix by a series of collected intensity. SVDGI enables the reconstruction of an N-pixel image using much less than N measurements, and perfectly reconstructs original object with N measurements. Both the simulated and the optical experimental results show that SVDGI always costs less time to accomplish better works. Firstly, it is at least ten times faster than GI and differential ghost imaging (DGI), and several orders of magnitude faster than pseudo-inverse ghost imaging (PGI). Secondly, in comparison with GI, the clarity of SVDGI can get sharply improved, and it is more robust than the other three methods so that it yields a clearer image in the noisy environment.

17.
Angew Chem Int Ed Engl ; 57(27): 8037-8042, 2018 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-29736959

RESUMO

Conventional syntheses of polymer-inorganic composite thermoelectric materials suffer major problems such as inhomogeneity, large particle size, and oxidation that result in ineffective loading. Now a one-step synthesis can be used to fabricate high-quality small-sized anions codoped poly(3,4-ethylenedioxythiophene):dodecylbenzenesulfonate/Cl-tellurium (PEDOT:DBSA/Cl-Te) composite films using a series of novel TeIV -based oxidants. The synchronized production of PEDOT and Te results in thick and homogeneous films containing evenly distributed and well-protected Te quantum dots. Owing to the heavily doped crystalline polymer matrix as well as the <5 nm unoxidized Te quantum dot loading, at low Te concentrations as 2.1-5.8 wt %, the films exhibits high power factors of about 100 µW m-1 K-2 , which is 50 % higher compared to a pure PEDOT:DBSA film.

18.
Nat Mater ; 17(5): 421-426, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29632407

RESUMO

Ductility is common in metals and metal-based alloys, but is rarely observed in inorganic semiconductors and ceramic insulators. In particular, room-temperature ductile inorganic semiconductors were not known until now. Here, we report an inorganic α-Ag2S semiconductor that exhibits extraordinary metal-like ductility with high plastic deformation strains at room temperature. Analysis of the chemical bonding reveals systems of planes with relatively weak atomic interactions in the crystal structure. In combination with irregularly distributed silver-silver and sulfur-silver bonds due to the silver diffusion, they suppress the cleavage of the material, and thus result in unprecedented ductility. This work opens up the possibility of searching for ductile inorganic semiconductors/ceramics for flexible electronic devices.

19.
ACS Appl Mater Interfaces ; 10(12): 10123-10131, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29498257

RESUMO

A novel quaternary Cu2MnSnSe4 diamondlike thermoelectric material was discovered recently based on the pseudocubic structure engineering. In this study, we show that introducing off-stoichiometry in Cu2MnSnSe4 effectively enhances its thermoelectric performance by simultaneously optimizing the carrier concentrations and suppressing the lattice thermal conductivity. A series of nonstoichiometric Cu2+δMn1-δSnSe4 (δ = 0, 0.025, 0.05, 0.075, and 0.1) samples has been prepared by the melting-annealing method. The X-ray analysis and the scanning electron microscopy measurement show that all nonstoichiometric samples are phase pure. The Rietveld refinement demonstrates that substituting part of Mn by Cu well maintains the structure distortion parameter η close to 1, but it induces obvious local distortions inside the anion-centered tetrahedrons. Significantly improved carrier concentrations are observed in these nonstoichiometric Cu2+δMn1-δSnSe4 samples, pushing the power factors to the theoretical maximal value predicted by the single parabolic model. Substituting part of Mn by Cu also reduces the lattice thermal conductivity, which is well interpreted by the Callaway model. Finally, a maximal thermoelectric dimensionless figure-of-merit zT around 0.60 at 800 K has been obtained in Cu2.1Mn0.9SnSe4, which is about 33% higher than that in the Cu2MnSnSe4 matrix compound.

20.
Water Sci Technol ; 76(9-10): 2427-2433, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29144300

RESUMO

The enhancement of sludge dewaterability is of great importance for facilitating the sludge disposal during the operation of wastewater treatment plants. In this study, a novel oxidative conditioning approach was applied to enhance the dewaterability of waste activated sludge by the combination of zero-valent iron (ZVI) and peroxymonosulfate (PMS). It was found that the dewaterability of sludge was significantly improved after the addition of ZVI (0-4 g/g TSS) (TSS: total suspended solids) and PMS (0-1 g/g TSS). The optimal addition amount of ZVI and PMS was 0.25 g/g TSS and 0.1 g/g TSS, respectively, under which the capillary suction time of the sludge was reduced by approximately 50%. The decomposition of sludge flocs could contribute to the improved sludge dewaterability. Economic analysis demonstrated that the proposed conditioning process with ZVI and PMS was more economical than the ZVI + peroxydisulfate and the traditional Fenton conditioning processes.


Assuntos
Ferro/química , Peróxidos/química , Esgotos/química , Águas Residuárias/química , Purificação da Água/métodos , Oxirredução , Eliminação de Resíduos Líquidos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA