Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 382
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Chem Commun (Camb) ; 55(85): 12801-12804, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31595277

RESUMO

Herein, for the first time, we find that the surface mass transport properties of catalysts play critical roles in determining the electrocatalytic NRR selectivity over the competitive HER in aqueous media on metallic Cu. In particular, by controlling the monolayer thickness of Cu nanoparticles with a minimum mass transport barrier, the faradaic efficiency (FE) of the NRR can be dramatically enhanced to 33% in the H-type cell test and even to 59% in a new-type Zn-N2 aqueous battery.

2.
Hereditas ; 156: 31, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31548836

RESUMO

Background: Cleidocranial dysplasia (CCD) is a rare autosomal dominant disorder mainly characterized by hypoplastic or absent clavicles, delayed closure of the fontanelles, multiple dental abnormalities, and short stature. Runt-related transcription factor 2 (RUNX2) gene variants can cause CCD, but are not identified in all CCD patients. Methods: In this study, we detected genetic variants in seven unrelated children with CCD by targeted high-throughput DNA sequencing or Sanger sequencing. Results: All patients carried a RUNX2 variant, totally including three novel pathogenic variants (c.722_725delTGTT, p.Leu241Serfs*8; c.231_232delTG, Ala78Glyfs*82; c.909C > G, p.Tyr303*), three reported pathogenic variants (c.577C > T, p.Arg193*; c.574G > A, p.Gly192Arg; c.673 C > T, p.Arg225Trp), one likely pathogenic variant (c.668G > T, p.Gly223Val). The analysis of the variant source showed that all variants were de novo except the two variants (c.909C > G, p.Tyr303*; c.668G > T, p.Gly223Val) inherited from the patient's father and mother with CCD respectively. Further bioinformatics analysis indicated that these variants could influence the structure of RUNX2 protein by changing the number of H-bonds or amino acids. The experimental result showed that the Gly223Val mutation made RUNX2 protein unable to quantitatively accumulate in the nucleus. Conclusions: The present study expands the pathogenic variant spectrum of RUNX2 gene, which will contribute to the diagnosis of CCD and better genetic counseling in the future.


Assuntos
Displasia Cleidocraniana/genética , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Núcleo Celular , Criança , Pré-Escolar , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Masculino , Mutação , Linhagem
3.
Anal Chem ; 91(20): 12611-12614, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31558016

RESUMO

Lysosomal ß-N-acetylhexosaminidase (Hex) has been reported to possess unique physiological performances. Detection and visualization of Hex in lysosome will be favorable to reveal the basis of its functions. However, Hex-specific fluorescent probes are rarely reported. In this study, we reported the first lysosome-targeting Hex-lighting-up aggregation-induced emission (AIE)-active fluorescent probe (GlcNAc-TPE) with remarkably large Stokes shift and high sensitivity and selectivity. GlcNAc-TPE can selectively locate in lysosome and visualize endogenous Hex in live HCT116 cells and in live mice with high stability and good biocompatibility, providing a useful AIE probe for real-time visualization of Hex in live samples.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31557385

RESUMO

Pathogen infections and cancer are two major human health problems. Herein, we report the synthesis of an organic salt photosensitizer (PS), called 4TPA-BQ, by a one-step reaction. 4TPA-BQ presents aggregation-induced emission features. Owing to the aggregation-induced reactive oxygen species generated and a sufficiently small ΔEST , 4TPA-BQ shows a satisfactorily high 1 O2 generation efficiency of 97.8 %. In vitro and in vivo experiments confirmed that 4TPA-BQ exhibited potent photodynamic antibacterial performance against ampicillin-resistant Escherichia coli with good biocompatibility in a short time (15 minutes). When the incubation duration persisted long enough (12 hours), cancer cells were ablated efficiently, leaving normal cells essentially unaffected. This is the first reported time-dependent fluorescence-guided photodynamic therapy in one individual PS, which achieves ordered and multiple targeting simply by varying the external conditions. 4TPA-BQ reveals new design principles for the implementation of efficient PSs in clinical applications.

5.
Appl Opt ; 58(25): 6891-6898, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31503659

RESUMO

Modal decomposition (MD) plays an increasingly important role in characterizing fiber beams. Several promising MD techniques have been proposed in literature, all of which are based on a common hypothesis that the modal field is coherently superposed by transverse modes. However, the partially coherent conditions have to be expected in general. In order to take account of this ordinary case, a novel MD scheme employing the Wigner distribution function (WDF) is introduced, which allows the decomposition of fiber beams without any restrictions regarding their degree of coherence. The four-dimensional (4D) WDF (two spatial and two spatial frequency dimensions) of the 2D fiber beam is reconstructed using the coded aperture technique. Based on the measured WDF and orthogonal property of transverse modes, the modal coefficients as well as the mutual modal degree of coherence will be determined unambiguously. The validity and reliability of the proposed approach are illustrated with numerical examples.

6.
J Genet Genomics ; 46(8): 397-404, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31471211

RESUMO

Understanding how gene expression is translated to phenotype is central to modern molecular biology, and the success is contingent on the intrinsic tractability of the specific traits under examination. However, an a priori estimate of trait tractability from the perspective of gene expression is unavailable. Motivated by the concept of entropy in a thermodynamic system, we here propose such an estimate (ST) by gauging the number (N) of expression states that underlie the same trait abnormality, with large ST corresponding to large N. By analyzing over 200 yeast morphological traits, we show that ST predicts the tractability of an expression-trait relationship. We further show that ST is ultimately determined by natural selection, which builds co-regulated gene modules to minimize possible expression states.

7.
Anal Biochem ; 585: 113403, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31465752

RESUMO

A new tetraphenylethylene derivative based fluorescenct probe (probe 2) was synthesized in a simple two-step process for selectively switch on and reversible detection of Hg2+ in aqueous solution based on aggregation-induced emission phenomenon. Probe 2 exhibited weak emission in aqueous solution due to the fast non-radiative decay of the excited singlet state facilitated by the free rotation of four phenyl rotors. While after coordination with Hg2+, the Hg2+-promoted aggregation formation will occur and restrict the intramolecular rotation, which blocks the non-radiative pathways and opens up the emission channel, resulting in the switch on response of probe 2 toward Hg2+. Probe 2 exhibited high sensitivity and good selectivity toward Hg2+ with a detection limit of 45.4 nM. Moreover, the detection can be reversible by subsequent addition of S2- into the detection system, which may be applied in the removal of toxic Hg2+ from water. Elsevier B.V. All rights reserved.

8.
Artigo em Inglês | MEDLINE | ID: mdl-31401083

RESUMO

To identify the effects of poplar secondary metabolites on Lymantria dispar, six poplar secondary metabolites (i.e., caffeic acid, salicin, rutin, quercetin, flavone, and catechol) and three mixtures containing characteristic secondary metabolites in poplar were selected. Mixture 1 contained flavone and salicin, mixture 2 contained salicin, caffeic acid, and catechol, and mixture 3 contained flavone, catechol, and caffeic acid. Mixtures were added to artificial diets used to feed 2nd instar L. dispar larvae. The effects of different secondary metabolites on larval growth and development, antifeedant activity, nutrient utilization, and detoxifying enzymatic activity were investigated. Results revealed that there were different influences on L. dispar larvae. The maximum antifeedant rate of flavone was 87.58%. Larvae treated with mixture 2 had a significantly longer development time of 5.61 d with a survival rate of 38.75% for 15 d, which is lower than a single secondary metabolite. No L. dispar larvae survived on feeding diets containing flavone for 7 d. An increase in GST and P450 activities in larvae was significantly induced during the 72 h feeding on artificial diets containing experimental secondary metabolites. After treatment containing salicin and flavone for 24-72 h, P450 activity increased at first then decreased. These results provide a foundation for further investigation on the host selection and underlying adaptation mechanisms in L. dispar.

9.
J Am Chem Soc ; 141(38): 15111-15120, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31436971

RESUMO

Acrylonitriles with aggregation-induced emission (AIE) characteristics have been found to show promising applications in two-photon biomedical imaging. Generally, elaborate synthetic efforts are required to achieve different acrylonitriles with distinct functionalities. In this work, we first reported the synthesis of two different group-functionalized AIE-active acrylonitriles (TPAT-AN-XF and 2TPAT-AN) obtained simply by mixing the same reactants at different temperatures using a facile and transition metal-free synthetic method. These two AIE luminogens (AIEgens) exhibit unique properties such as bright red emission in the solid state, large Stokes shift, and large two-photon absorption cross section. Water-soluble nanoparticles (NPs) of 2TPAT-AN were prepared by a nanoprecipitation method. In vitro imaging data show that 2TPAT-AN NPs can selectively stain lysosome in live cells. Besides one-photon imaging, remarkable two-photon imaging of live tumor tissues can be achieved with high resolution and deep tissue penetration. 2TPAT-AN NPs show high biocompatibility and are successfully utilized in in vivo long-term imaging of mouse tumors with a high signal-to-noise ratio. Thus, the present work is anticipated to shed light on the preparation of a library of AIE-active functionalized acrylonitriles with intriguing properties for biomedical applications.

10.
Chemosphere ; 236: 124319, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31310981

RESUMO

Thermally enhanced remediation of n-alkanes-contaminated silty soil mixed with coarse quartz sands was demonstrated in a laboratory cylindrical tank with diameter of 40 cm and depth of 30 cm. The removal kinetics of semi-volatile n-alkanes (C10, C11, C13-16) under three pulsed heating operations of soil vapor extraction (SVE) was investigated. CMG-STARS software was adopted to simulate the dynamics of heat transfer within the soil column. The results indicated the dramatic increase of air permeability of soil and acceleration of heat transfer after introduction of sand, with the result of achieving rapid soil remediation. Gas-phase transfer of n-alkanes mainly occurred when average soil temperature was ≥100 °C. At the end of remediation with soil subjected to heating for 30.8 h (total running time), the average soil concentration of total n-alkanes was reduced from initial 3106.5 to 202.4 mg/kg, corresponding to 93.4% of mass removal. The residual n-alkanes of C10, C11, C13 and C14 in all collected soil samples were declined to levels of lower than 10 mg/kg. Most of the soil concentration-gradient curves for n-alkanes tested almost coincided with their isothermal contours, indicating the key impact of thermal drive force on contaminant transfer.

11.
Rev Sci Instrum ; 90(6): 065112, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31254982

RESUMO

Signal detection and processing have become an important way to diagnose mechanical faults. The classical bistable stochastic resonance (CBSR) method for signal detection can become saturated, where the amplitude of the output signal gradually stabilizes at a relatively low level instead of increasing with further increases of the input signal amplitude. This leads to difficulty in extracting the weak signals from strong background noise. We studied a new mechanism based on unsaturated piecewise linear stochastic resonance (PLSR). The piecewise linear potential model has a unique structure, which can independently adjust the barrier height and potential wall inclination, so the piecewise linear potential model has a rich potential structure. The rich potential structure makes the potential model unsaturated, thus ensuring that the output signals increase as the input signals increase. In addition, according to the piecewise linear model, the output signal-to-noise ratio (SNR) of the system is deducted. Analysis of the influence of signal strength, potential parameters, and angular frequency on the SNR shows that the optimal SNR can be obtained by adjusting the potential parameters. We propose a weak signal detection method for bearing fault diagnosis. This method can effectively extract the weak fault signals from rolling bearings in a strong noise background. The simulated and experimental bearing fault signals verify that the proposed PLSR method is superior to the CBSR method.

12.
Anal Chem ; 91(15): 9388-9392, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31315395

RESUMO

Carbon monoxide (CO) is a significant gasotransmitter that naturally modulates inflammatory responses. Visualization of CO in situ would help to reveal its physiological/pathological functions. Unfortunately, most existing CO fluorescent probes show aggregation-caused quenching (ACQ) properties. Herein, we report the reaction-based fluorescent probe (BTCV-CO) with aggregation-induced emission (AIE) characteristics for CO detection and imaging. This ratiometric AIE probe showed excellent stability, high sensitivity (detection limit of 30.8 nM), and superior selectivity. More importantly, this CO-responsive AIE probe could be facilely designed and easily obtained by two-step synthesis with high yield, providing an easy-to-handle AIE toolbox for real-time visualization of CO in a living system.

13.
Int Immunopharmacol ; 74: 105727, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31284229

RESUMO

The existence of association between the subpopulation of iNKT cells with different functions and nonalcoholic fatty liver disease has not been confirmed. To investigative the role of iNKT cells in the pathogenesis of nonalcoholic fatty liver disease, we established a non-alcoholic fatty liver model by feeding C57BL/6J mice for 12 weeks with a high-fat diet and injecting α-GalCer through different routes to activate hepatic iNKT cells. The liver of the mice fed a high-fat diet (HFD) had severe hepatic steatosis appearance, elevated pro-inflammatory cytokines and reduced anti-inflammatory cytokines in the liver, and high serum levels of TC, LDL, HDL, and ALT. Our results showed that the percentage of iNKT cells in the liver of the HFD-fed mice was lower than that of the control mice. The expression levels of the related transcription factor of T-bet increased but that of GATA-3 decreased in the HFD-fed mice. The administration of α-GalCer by intraperitoneal injection resulted in increasing of hepatic iNKT and iNKT2 cells but decreasing of hepatic iNKT1 cells, and the expression of GATA-3 and anti-inflammatory cytokine (IL-4) was increased in the liver, and hepatic steatosis was ameliorated in the HFD-fed mice. The administration of α-GalCer by subcutaneous injection resulted in a decrease in hepatic iNKT and iNKT2 and an augmentation of hepatic iNKT1 cells. However, hepatic steatosis was not significantly improved. We concluded that the intraperitoneal injection with α-GalCer effectively improved hepatic steatosis, according to increasing the number of hepatic iNKT2 cells. The precise mechanism requires further exploration.

16.
J Trace Elem Med Biol ; 55: 15-19, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31345353

RESUMO

The trace element strontium has a significant impact on cartilage metabolism. However, the direct effects of strontium on alkaline phosphatase (ALP), a marker of bone growth, and bone morphogenetic protein-4 (BMP-4), which plays a key role in the regulation of bone and cartilage development, are not entirely clear. In order to understand the mechanisms involved in these processes, the chondrocytes were isolated from Wistar rat articular cartilage by enzymatic digestion and cultured under standard conditions. They were then treated with strontium at 0.5, 1.0, 2.0, 5.0, 20.0 and 100.0 µg/mL for 72 h. The mRNA abundance and protein expression levels of ALP and BMP-4 were measured using real-time polymerase chain reaction (real-time PCR) and Western blot analysis. The results showed that the levels of expression of ALP and BMP-4 in chondrocytes increased as the concentration of strontium increased relative to the control group, and the difference became significant at 1.0 µg/mL strontium (P<0.05). These results indicated that strontium could be involved in cartilage development via regulating ALP and BMP-4 expression.

17.
Am J Physiol Cell Physiol ; 317(3): C525-C533, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31291142

RESUMO

p38-Regulated/activated protein kinase (PRAK) plays a critical role in modulating cellular survival and biological function. However, the function of PRAK in the regulation of myocardial ischemic injury remains unknown. This study is aimed at determining the function of PRAK in modulating myocardial ischemia-reperfusion injury and myocardial remodeling following myocardial infarction. Hearts were isolated from adult male homozygous PRAK-/- and wild-type mice and subjected to global ischemia-reperfusion injury in Langendorff isolated heart perfusion. PRAK-/- mice mitigated postischemic ventricular functional recovery and decreased coronary effluent. Moreover, the infarct size in the perfused heart was significantly increased by deletion of PRAK. Western blot showed that deletion of PRAK decreased the phosphorylation of ERK1/2. Furthermore, the effect of deletion of PRAK on myocardial function and remodeling was also examined on infarcted mice in which the left anterior descending artery was ligated. Echocardiography indicated that PRAK-/- mice had accelerated left ventricular systolic dysfunction, which was associated with increased hypertrophy in the infarcted area. Deletion of PRAK augmented interstitial fibrosis and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL)-positive myocytes. Furthermore, immunostaining analysis shows that CD31-postive vascular density and α-smooth muscle actin capillary staining decreased significantly in PRAK-/- mice. These results indicate that deletion of PRAK enhances susceptibility to myocardial ischemia-reperfusion injury, attenuates cardiac performance and angiogenesis, and increases interstitial fibrosis and apoptosis in the infarcted hearts.

18.
J Hazard Mater ; 378: 120751, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31220648

RESUMO

Electrospun nanofibers have a wide range of applications due to their unique miniature size and accompanying ultra-high specific surface area. Polyvinyl alcohol(PVA) is a kind of hydrophilic materials, and hence its nanofiber morphology prepared by electrospinning disappeared after solution immersing. In the present work, crosslinked PVA nanofibers were prepared by electrospinning and then employing glutaraldehyde vapor crosslinking to improve their water resistance and mechanical properties. As an application, these nanofibers were used to adsorb Cu2+ and Pb2+ according to varying crosslinking time and different concentrations of ionic solution. It was observed the crosslinked PVA nanofiber films maintained good fiber morphology after adsorption, while the nanofiber morphology of uncrosslinked samples was lost. The stability of the crosslinked nanofiber films in water was improved, the adsorption equilibrium time of Pb2+ decreased from 30 h to 10 h while the equilibrium adsorption time of Cu2+ decreased from 15 h to 5 h, and the tensile strength of the nanofiber films with crosslinking time of 20 h was 7.99 MPa, which was 240% higher than that of the nanofiber with crosslinking time of 1 h, indicating higher efficiency.

19.
J Am Chem Soc ; 141(25): 9803-9807, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31204478

RESUMO

Many aggregation-induced emission (AIE) materials are featured by the diphenylethene (DPE) moiety which exhibits rich photophysical and photochemical activities. The understanding of these activities behind AIE is essential to guide the design of fluorescent materials with improved performance. Herein by fusing a flexible DPE with a rigid spiro scaffold, we report a class of novel deep-blue material with solid-state fluorescent quantum yield (ΦF) up to 99.8%. Along with the AIE phenomenon, we identified a reversible photocyclization (PC) on DPE with visible chromism, which is, on the contrary, popularized in solutions but blocked by aggregation. We studied the steric and electronic effects of structural perturbation and concluded that the PC is a key process behind the RIMs (restriction of intramolecular motions) mechanism for these materials. Mitigation of the PC leads to enhanced fluorescence in solutions and loss of the AIE characteristics.

20.
Phys Chem Chem Phys ; 21(24): 12895-12904, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31157340

RESUMO

Brittle porous materials offer a wide variety of promising applications due to their high surface-area-to-volume ratios and controllable porous structures. Getting comprehensive knowledge of the structural stability is of great significance for avoiding the irreversible destruction of these materials. Based on interpenetrating bicontinuous structures, we innovatively adopted a sequential mesoscopic simulation strategy to show the pore size effect on the mechanical stability, which involves structural evolution by the mesoscale dynamic density functional method and mechanical behavior by the highly efficient lattice spring model. Simulation results show that specific surface areas, Young's moduli and fracture strains decrease with the increase of pore widths on the premise of the same porosity. More uniform stress/strain distributions are observed in structures with smaller pore sizes or more uniform defect distributions. From the local stress distribution analysis, the effective stress transfer occurs in the solid phase, which runs through the simulation box along the tensile direction, and the mechanical disparity among systems with different pore sizes is due to different volume fractions and microstructures of the solid phase. Larger pore sizes result in lower Weibull moduli due to the increased heterogeneity and a less predictable failure behavior, and the concentrated defects usually result in mechanical anisotropy.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA