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1.
J Nanosci Nanotechnol ; 20(6): 3348-3355, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31748026

RESUMO

In marine environment, alkaline phosphatase (ALP) is a nonspecific phosphatase with metal ions as its active site. Metal ions have different effects on ALP activity. Therefore, a probe that specifically detects ALP needs to be developed. In this paper, to eliminate the interference of acid phosphatase, we designed and synthesized a highly selective fluorescent probe CyP based on pH to detect ALP activity. The response mechanism of detecting ALP was explained. The photophysical properties, enzyme kinetics, stability, selectivity, and potential quantitative ability of the probe under different pH values were investigated. The effects of metal ions on the ALP activity of marine Chlorella vulgaris and Escherichia coli were also analyzed. Excessive metal ions such as Zn2+, Cu2+, Hg2+, Pb2+, and Cd2+ inhibit while Mn2+, Co2+, and alkaline-earth metal ions promote the ALP activity of Chlorella and E. coli.

2.
Food Chem ; 308: 125599, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31648098

RESUMO

In this work, sequential electrospinning was utilized to fabricate a multilayer film with ethylcellulose nanofibers as the outer layer and curcumin-loaded gelatin nanofibers as the inner layer. Field-emission scanning electronic microscopy observations showed that the outer and inner layers had a smooth surface and clear boundary. The hydrophobic outer layers decreased the water vapor permeability and improved the water contact resistance of the hydrophilic inner layer, and the intimate interactions of hydrogen bonds between two adjacent layers enhanced the thermal stability. The multilayer film exhibited a sustained release manner of the encapsulated curcumin for 96 h, compared to the burst release within 30 min from the gelatin film. In addition, the antioxidant activities of the released curcumin from the multilayer film were well retained within 96 h. These results suggested that the multilayer nanofibrous film fabricated by sequential electrospinning has potential applications in bioactive encapsulation and controlled release.

3.
Food Microbiol ; 86: 103340, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31703864

RESUMO

Red sufu is a traditional food produced by the fermentation of soybean. In this study, sufu samples were periodically collected during the whole fermentation to investigate the dynamic changes of fungal and bacterial communities using high-throughput sequencing technology. The overall process can be divided into pre- and post-fermentation. During post-fermentation, the pH value showed a gradual decrease over time while the amino nitrogen content increased. Trichosporon, Actinomucor and Cryptococcus were the main genera in pre-fermentation while Monascus and Aspergillus were dominant in post-fermentation. This huge shift in fungal composition was caused by process procedure of pouring dressing mixture. However, the bacterial composition was not greatly changed after pouring dressing mixture, the Acinetobacter and Enterobacter were the predominant genera throughout the whole process. Furthermore, Bacillus species were first detected after adding dressing mixture, but declined abruptly to a very low level (0.07%) by the end of the fermentation. Our work demonstrates the dynamic changes of physicochemical properties and microbial composition in every fermentation stage, the knowledge of which could potentially serve as a foundation for improving the safety and quality of sufu in the future.

4.
Mater Sci Eng C Mater Biol Appl ; 107: 110269, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761213

RESUMO

It is a dilemma that both strength and biocompatibility are requirements for an ideal scaffold in tissue engineering. The normal strategy is mixing or coating another material to improve the biocompatibility. Could we solve this dilemma by simply adjusting the scaffold structure? Here, a novel multi-scale scaffold was designed, in which thick fibers provide sufficient strength for mechanical support while the thin fibers provide a cell-favorable microenvironment to facilitate cell adhesion. Moreover, we developed a promising multi-scale direct writing system (MSDWS) for printing the multi-scale scaffolds. By switching the electrostatic field, scaffolds with fiber diameters from 3 µm to 600 µm were fabricated using one nozzle. Using this method, we proved that PCL scaffolds could also have excellent biocompatibility. BMSCs seeded on the scaffolds readily adhered to the thin fibers and maintained a high proliferation rate. Moreover, the cells bridged across the pores to form a cell sheet and gradually migrated to the thick fibers to cover the entire scaffold. We further combined the scaffolds with hydrogel for 3D cell culture and found that the fibers enhanced the strength and induced cell migration. We believe that the multi-scale scaffolds fabricated by an innovative 3D printing system have great potential for tissue engineering.

5.
Chemosphere ; 240: 124977, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726600

RESUMO

In this study, Fe3O4 and microwave (MW) were combined to activate persulfate (PS) for the removal of organic matter, resulting in the enhanced degradation of p-nitrophenol (PNP) in solution. During the preparation of Fe3O4, the effect of sodium acetate was examined, and the results showed that the concentration of sodium acetate had little effect on the catalytic activity of the Fe3O4/PS/MW system but did have an effect on the Fe3O4 yield. In addition, with regards to the representative environmental factors, the degradation experiment showed that humic acid and the co-existing anions of chloride, sulfate, nitrate, and phosphate had little effects on p-nitrophenol removal; however, carbonate had a negative effect. In addition, the Fe3O4/PS/MW system performed well in the initial pH range of 3.0-9.0. According to the quenching experiment and electron paramagnetic resonance (EPR) detection, sulfate radicals and a minority of hydroxyl radicals play dominant roles in the degradation process. In addition, the role of Fe3O4 was confirmed to take part in the degradation process by X-ray photoelectron spectroscopy (XPS) analysis. Because of the good performance observed in the water matrices of tap water and the Songhua River, these results demonstrate the potential application of the Fe3O4/PS/MW system for wastewater treatment.

6.
J Theor Biol ; 484: 110006, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31539529

RESUMO

Quantitative predictions of FtsZ protein polymerization are essential for understanding the self-regulating mechanisms in biochemical systems. Due to structural complexity and parametric uncertainty, existing kinetic models remain incomplete and their predictions error-prone. To address such challenges, we perform probabilistic uncertainty quantification and global sensitivity analysis of the concentrations of various protein species predicted with a recent FtsZ protein polymerization model. Our results yield a ranked list of modeling shortcomings that can be improved in order to develop more accurate predictions and more realistic representations of key mechanisms of such biochemical systems and their response to changes in internal or external conditions. Our conclusions and improvement recommendations can be extended to other kinetics models.

7.
Theriogenology ; 141: 142-145, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31541783

RESUMO

The safety of assisted reproductive technology (ART) is of frequent concern. Unfortunately, animal models for studying the safety of intracytoplasmic sperm injection (ICSI) have limitations in mimicking human ICSI manipulations. As reported herein, we invented a modified holding pipette for mouse oocyte injection that resulted in the delivery of live pups. A modified holding pipette was prepared for mouse oocyte injection and was compared with the conventional pipette for human use and a trumpet-shaped pipette. After ICSI, the oocytes were cultured to cleavage embryos until fallopian transfer. The use of the trumpet-shaped holding pipette and the new modified holding pipette for mouse oocyte injection achieved comparable and satisfactory oocyte survival rates (83.44% and 85.71%, respectively) and embryo cleavage rates (41.98% and 42.42%, respectively), which were significantly higher than those obtained with the human egg-holding pipette (oocyte survival rate: 65.85%; embryo cleavage rate: 27.78%). After 13 embryos were transferred using each type of pipette, three live pups were produced with the new modified holding pipette, one was produced with the holding pipette for human use, and none were produced with the trumpet-shaped holding pipette. The modified holding pipette for oocyte injection is effective and very easy to prepare. Moreover, using this new method, we produced live pups, which will contribute to a useful animal model for safety studies of ICSI in the future.

8.
Opt Express ; 27(19): 27039-27045, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31674572

RESUMO

In this paper, a nematic liquid crystal (NLC)-based tunable terahertz (THz) plasmonic metamaterials (MMs) with large modulation depth (MD) and low insertion loss (IL) is designed and experimentally verified at THz frequencies. The proposed structure includes two-layered MM that is immersed in LC. The metal MM is used directly as electrode. The tunable device with a 46×46 array of sub-wavelength circular air loops was fabricated on a quartz glass substrate, with 2×2 cm2 area and 220 µm thickness. The obtained results show that the amplitude MD and IL for normally incident electromagnetic (EM) waves are about 96% and 1.19 dB at 421.2 GHz, respectively, when the bias voltage applied to the NLC layer varies from 0 to 16 V. Meanwhile, the transmission peak frequency gradually decreases from 421.2 to 381.8 GHz, and the frequency tunability (FT) of the proposed structure is greater than 9.35%. This study provides a potential solution for THz modulators, filters, and switches.

9.
Opt Lett ; 44(21): 5370-5373, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31675009

RESUMO

An all-fiber orbital angular momentum (OAM) generator enabling direct turning of the fundamental mode (${{\rm HE}_{11}}$HE11) to the second OAM modes (${ l} = {\pm 2}$l=±2) with an efficiency of $\sim90\% $∼90% has been proposed and experimentally demonstrated, which is realized based on utilization of a second-order helical fiber grating written in a few-mode fiber. This is the first time, to the best of our knowledge, that an all-fiber second-order OAM has been achieved with using only one component, i.e., the helical long-period fiber grating. The proposed method opens a new way to efficiently generate an all-fiber higher-order OAM using a conventional multimode fiber.

10.
Water Res ; 169: 115205, 2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31670086

RESUMO

The release of silver nanomaterials (AgNMs) from extensive use poses potential risks to human health and ecological environments. Although previous studies have reported the negative effects of AgNMs on various microorganisms, little is known about the response of bacteria under the exposure of AgNMs at the cellular level. Here, we report the multiple responses of Pseudomonas aeruginosa PAO1 (PAO1) under the exposure of two types of AgNMs, including spherical silver nanoparticles (AgNPs) and fibrous silver nanorods (AgNRs), by physiological experiments, microscopy, synchrotron-based X-ray Absorption Spectroscopy (XAS), flow cytometry and genome-wide RNA sequencing. Our results demonstrated that the exposure to both types of AgNMs could inhibit the growth of PAO1, accompanied by the overproduction of oxidative stress and inducing cell membrane damage. Transmission electron microscopy revealed the roughened cell membrane under both AgNMs treatment. In addition, both AgNMs repressed the expression of quorum sensing and metal efflux-related genes in PAO1, but stimulated denitrification, glycerol and amino acid metabolisms, SOS response and pyocin overproduction of PAO1. Compared to AgNRs, AgNPs exposure showed a much lower threshold concentration to trigger the inhibitory effect and induced greater transcriptional responses of PAO1. This study suggested that AgNMs could cause multiple effects on the proliferation, metabolism, virulence and pathogenesis of PAO1, which might further affect the corresponding environmental microbial communities. Overall, our findings offer insights into the interactions between AgNMs and bacteria at the molecular level.

12.
Anal Chem ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31718156

RESUMO

The matrix plays a prominent role in expanding the ability of matrix assisted laser desorption/ionization mass spectrometry (MALDI MS). However, on account of the unclarity of necessary properties of the matrix in MALDI MS, development of a new matrix is still in the exploratory stage and lacks systematic theoretical guidance. Meanwhile, most of the existing matrices are unable to simultaneously detect various high-molecular-weight (high-MW) lipids including (poly-)phosphoinositides, cardiolipins, and gangliosides. In this study, we have successfully screened and optimized the application of commercially available IR-780 as a novel matrix for simultaneously profiling and imaging high-MW lipids in brain tissues by MALDI MS for the first time. The properties of IR-780 related to the matrix of MALDI MS, mainly including the optical properties (UV absorption, fluorescence emission, and photothermal efficiency), proton affinity, collision cross-sections (CCSs), salt-tolerance ability, and homogeneity, were comprehensively characterized, which demonstrated that high photothermal ability and large CCSs might guarantee the superior performance of IR-780 as matrix for the analysis of high-MW lipids in biological samples. This work provided some references for the development of a novel matrix, and especially, the concept of CCS was first introduced as a parameter for the development of a matrix. In addition, the simultaneous identification and imaging of endogenous high-MW lipids in rat brain tissues subjected to traumatic brain injury were successfully performed.

13.
Sci Rep ; 9(1): 16924, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31729455

RESUMO

Roots account for a major part of plant biomass in Tibetan alpine meadows. Understanding root decomposition with global change is key to predict carbon (C) and nutrient dynamics on the Qinghai-Tibet Plateau. Yet, few experiments have carefully examined root decomposition as influenced by global change. We conducted a field study to investigate the effects of nitrogen (N) addition, air warming, precipitation change, and the presence/absence of living roots on root decomposition in a Tibetan alpine meadow. Our results showed that N addition increased the mass and C remaining, and induced N accumulation in the litter. Increased precipitation significantly amplified the positive effect of N addition on litter mass remaining. The presence of alive roots in the litterbags decreased root litter C remaining but significantly increased N and phosphorus remaining of the litter. However, we did not find any significant effects of air warming on the litter decomposition. In the Qinghai-Tibet Plateau, N deposition is predicted to increase and precipitation regime is predicted to change. Our results suggest that the interaction between increased N and precipitation may reduce root decomposition in the Qinghai-Tibet Plateau in the future, and that the large stock of living roots exert a dominant impact on nutrient dynamics of root decomposition in the Tibetan alpine systems.

14.
J Environ Manage ; 255: 109846, 2019 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-31747628

RESUMO

This study evaluates the applicability of using long-term satellite rainfall estimate (SRE) precipitation products in drought monitoring over mainland China under global warming conditions. Two widely used drought indices, the self-calibrating Palmer Drought Severity Index (scPDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI), were selected as study cases; both indices consider global warming but based on different mechanisms. Two popular long-term SREs were selected to calculate the indices: the Precipitation Estimation from Remotely Sensed Information using the Artificial Neural Networks-Climate Data Record (PERSIANN-CDR), and the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS). A ground-based gridded observation dataset known as the China monthly Precipitation Analysis Product (CPAP) was used as a reference for the evaluation. Research results showed that on a grid cell scale, the SPEI based on both SREs was consistent with observations in eastern China (correlation coefficient over 0.9), while the scPDSI was much less accurate (correlation coefficient of only 0.5) and its accuracy patterns were highly spatially heterogeneous. However, on a regional scale, after spatial errors were offset by spatial averaging, the performance of the SRE-based scPDSI improved, and it showed the same ability as the SPEI in temporally detecting the timing, intensity, and magnitude of drought. The self-calibrating procedure of the scPDSI was determined as the most probable cause of its poorer performance and high heterogeneity, which would increase instability and enlarge the uncertainty of the SREs. It is thus considered that the SPEI should be the first choice for use in monitoring global-warming related drought, primarily because of the high uncertainty and instability of the scPDSI.

15.
Mol Ther Nucleic Acids ; 18: 903-915, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31760375

RESUMO

miR-29a-3p has been shown to be associated with cardiovascular diseases; however, the effect of miR-29a-3p on endothelial dysfunction is unclear. This study aimed to reveal the effects and mechanisms of miR-29a-3p on endothelial dysfunction. The levels of vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and E-selectin were determined by real-time PCR and immunofluorescence staining to reveal the degree of tumor necrosis factor alpha (TNFα)-induced endothelial dysfunction. A luciferase activity assay and cell transfection with a miR-29a-3p mimic or an inhibitor were used to reveal the underlying mechanisms of miR-29a-3p action. Furthermore, the effects of miR-29a-3p on endothelial dysfunction were assessed in C57BL/6 mice injected with TNFα and/or a miR-29a-3p agomir. The results showed that the expression of TNFα-induced adhesion molecules in vascular endothelial cells (EA.hy926 cells, human aortic endothelial cells [HAECs], and primary human umbilical vein endothelial cells [pHUVECs]) and smooth muscle cells (human umbilical vein smooth muscle cells [HUVSMCs]) was significantly decreased following transfection with miR-29a-3p. This effect was reversed by cotransfection with a miR-29a-3p inhibitor. As a key target of miR-29a-3p, tumor necrosis factor receptor 1 mediated the effect of miR-29a-3p. Moreover, miR-29a-3p decreased the plasma levels of TNFα-induced VCAM-1 (32.62%), ICAM-1 (38.22%), and E-selectin (39.32%) in vivo. These data indicate that miR-29a-3p plays a protective role in TNFα-induced endothelial dysfunction, suggesting that miR-29a-3p is a novel target for the prevention and treatment of atherosclerosis.

16.
Exp Lung Res ; 45(9-10): 288-296, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31762326

RESUMO

Objective: This study aimed to explore the differentially expressed genes (DEGs) of pulmonary macrophages in human idiopathic pulmonary fibrosis (IPF) by bioinformatics, and elaborate on IPF on the gene level. Methods: The gene expression profile GSE49072 was downloaded from the gene expression omnibus (GEO) database. Genes of alveolar macrophages between normal volunteers and patients diagnosed as IPF were analyzed by GEO2R tools. Gene ontology (GO) and pathway enrichment analyses of genes were performed in the database for annotation, visualization and integrated discovery (DAVID) database, followed by functional annotation and protein-protein interaction (PPI) network construction in String website. Finally, the results were analyzed in a comprehensive way. Results: A total of 551 DEGs, including 205 down-regulated and 346 up-regulated were identified. The expression of 209875_s_at (secreted phosphoprotein 1, SPP1) and 214146_s_at (pro-platelet basic protein, PPBP) genes are the most significant in upregulated genes. DEGs in the MAPK(mitogen-activated protein kinase) signaling pathway and chemokine signaling pathway play important roles in the development of IPF. Conclusions: The up-regulation of genes such as SPP1 and PPBP affect the secretion of alveolar macrophages, thereby speeding up the process of fibrosis.

17.
Nanoscale ; 11(45): 22025-22032, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31714556

RESUMO

Studies have concentrated on the physicochemical properties of graphene-based membranes that can replace polymeric membranes for use in forward osmosis (FO) systems. However, recent research studies have focused on mixtures of two or more different materials (e.g., graphene oxide and polymers) due to the need to reinforce underwater stability. Alternatives include reduced forms such as reduced graphene oxide to improve the stability and size-based selectivity, which have resulted in a narrow nanochannel that restricts water permeability. Herein, we propose the use of a novel nitrogen-doped graphene (NG) membrane to solve a trade-off between permeability and selectivity, investigating the nanostructure via N-doping reaction time. In an FO process, NG membranes achieved an outstanding specific salt flux of 0.18 g L-1, compared to commercial membranes (0.55 g L-1). The pyridinic-N bonding structure improved the permeability and selectivity under a similar nanochannel size because of its negatively polarized hole defects with the moderate energy barrier enabling water passage while blocking ions. Our results confirm the possibility of fabricating novel graphene-based FO membranes by tailoring the nitrogen-bonding structure, which will significantly help develop a process for improving the scalability of membrane materials.

18.
Sci Rep ; 9(1): 16973, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31740721

RESUMO

Kinesin-3 and kinesin-1 molecular motors are two families of the kinesin superfamily. It has been experimentally revealed that in monomeric state kinesin-3 is inactive in motility and cargo-mediated dimerization results in superprocessive motion, with an average run length being more than 10-fold longer than that of kinesin-1. In contrast to kinesin-1 showing normally single-exponential distribution of run lengths, dimerized kinesin-3 shows puzzlingly Gaussian distribution of run lengths. Here, based on our proposed model, we studied computationally the dynamics of kinesin-3 and compared with that of kinesin-1, explaining quantitatively the available experimental data and revealing the origin of superprocessivity and Gaussian run length distribution of kinesin-3. Moreover, predicted results are provided on ATP-concentration dependence of run length distribution and force dependence of mean run length and dissociation rate of kinesin-3.

19.
Nat Commun ; 10(1): 5344, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31745076

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

20.
Aging (Albany NY) ; 112019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31754082

RESUMO

There have been an increasing number of functional magnetic resonance imaging (fMRI) reports on brain abnormalities in mild traumatic brain injury (mTBI) at different phases. However, the neural bases and cognitive impairment after acute mTBI are unclear. This study aimed to identify brain functional hubs and connectivity abnormalities in acute mTBI patients and their correlations with deficits in cognitive performance. Within seven days after brain injury, mTBI patients (n=55) and age-, sex-, and educational -matched healthy controls (HCs) (n=41) underwent resting-state fMRI scans and cognitive assessments. We derived functional connectivity (FC) strength of the whole-brain network using degree centrality (DC) and performed Granger causality analysis (GCA) to analyze causal connectivity patterns in acute mTBI. Compared with HCs, acute mTBI patients had significantly decreased network centrality in the left middle frontal gyrus (MFG). Additionally, acute mTBI showed decreased inflows from the left MFG to bilateral middle temporal gyrus (MTG), left medial superior frontal gyrus (mSFG), and left anterior cingulate cortex (ACC). Correlation analyses revealed that changes in network centrality and causal connectivity were associated with deficits in cognitive performance in mTBI. Our findings may help to provide a new perspective for understanding the neuropathophysiological mechanism of acute cognitive impairment after mTBI.

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