MicroRNAs (miRNAs) are implicated in the progression of ischemic stroke (IS) and bone marrow-derived mesenchymal stem cells (BMSCs)-derived exosomes play a role in IS therapy. Herein we hypothesized ...that the BMSCs-derived exosomes containing overexpressed miR-138-5p could protect the astrocytes following IS involved with lipocalin 2 (LCN2).
The differentially expressed gene related to IS was initially identified by bioinformatics analysis. miR-138-5p was predicted to regulate LCN2. The expression of miR-138-5p and LCN2 was altered in the oxygen-glucose deprivation (OGD)-induced astrocytes. Furthermore, the cell behaviors and inflammatory responses were evaluated both in astrocytes alone and astrocytes co-cultured with exosomes derived from BMSCs overexpressing miR-138-5p to explore the involvement of miR-138-5p and LCN2 in IS. Besides, middle cerebral artery occlusion (MCAO) mouse model was established to explore the effect of BMSCs-derived exosomal miR-138-5p in IS in vivo.
LCN2 was highly expressed in IS. Besides, LCN2 was a target gene of miR-138-5p. BMSCs-derived exosomes could be endocytosed by astrocytes via co-culture. Overexpression of miR-138-5p promoted the proliferation and inhibited apoptosis of astrocytes injured by OGD, accompanied by the reduced expression of inflammatory factors, which was achieved by down-regulating LCN2. More importantly, BMSCs delivered miR-138-5p to the astrocytes via exosomes and BMSCs-derived exosomal miR-138-5p alleviated neuron injury in IS mice.
BMSCs-derived exosomal miR-138-5p reduces neurological impairment by promoting proliferation and inhibiting inflammatory responses of astrocytes following IS by targeting LCN2, which may provide a novel target for IS treatment.
Organic/inorganic hybrid membranes for separation applications have been widely studied. However, achieving a uniform dispersion of inorganic fillers in the polymer matrix is a primary challenge in ...the advancement of mixed-matrix membranes (MMMs). In the present study, a method for in situ assembly enhanced by sonication was developed to prepare hydrophobic polydimethylsiloxane (PDMS)/nanoparticle hybrid membranes. Results from scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrometry, and atomic force microscopy (AFM) suggest that through ultrasonic cavitation during assembly of the hybrid membrane, this method could effectively avoid nanoscale agglomeration and in turn uniformly disperse inorganic particles within the polymer matrix. This method thus enabled the preparation of an organophilic membrane with higher hydrophobicity and higher performance. For example, the contact angle (CA) of SiO2/PDMS hybrid membrane increased from 135.5° to 146.3°, and the separation factor for the pervaporation of 5% ethanol/water mixture increased from 7.3 to 12.5. Furthermore, the method was used to prepare a zeolite imidazolate framework-8 (ZIF-8)-filled PDMS membrane. The ZIF-8/PDMS hybrid membrane showed high performance in the pervaporation of alcohol/water mixtures. These results further suggest that in situ assembly via sonication is a promising approach to improve the dispersion of inorganic fillers and thus the membrane performance.
•Sonication-enhanced in situ assembly of organic/inorganic hybrid membranes.•Ιmprovement of the dispersion of inorganic filler in polymeric matrix in the nanoscale range.•An increase in pervaporation performance by in situ sonication-enhanced strategy.
This paper is aimed at researching and designing LDOs without off-chip capacitors. Whether the LDO can stabilize the output voltage when there is no external capacitor is studied. Based on this, a ...new type of high-stability LDO structure with no off-chip capacitor is studied to apply power to the internal circuit module in the DC-DC converter. The poles of the LDO are adjustd by adjusting the internal op amp structure and Miller compensation of the op amp. The simulation results show that the structure has high stability and can output a stable voltage.
This is a retrospective observational study conducted in one of the largest clinical center of neurosurgery in China. Our aim was to determine the epidemiological characteristics of ...carbapenem-resistant Enterobacteriaceae (CRE) related meningitis/encephalitis and to elucidate the risk factors for CRE neurosurgical infections.
We performed a retrospective study between January 2012 and December 2017 of patients who underwent neurosurgery. The medical records of each patient were reviewed, and 20 clinical variables on risk factors were extracted and evaluated by Multivariate logistic analysis for CRE-meningitis/encephalitis.
In 2012–2017, the positive rate of neurosurgical meningitis/encephalitis was 7.9% (2947/29605), Enterobacteriaceae accounted for 6.3% (185/2947) of all bacterial infections. Totally, 133 Enterobacteriaceae include 26 CRE isolates were available in this study. Of them, Univariate analysis showed that the risk factors of CRE meningitis were ventilator, bacteremia, Intensive Care Unit (ICU) admission, hospital acquired pneumonia and mortality attribute to infection. Multivariate logistic analysis showed that hospital acquired pneumonia and mortality attribute to infection were independent risk factors for CRE meningitis.
CRE is one of the most serious drug-resistant bacteria published by World Health Organization (WHO) in 2016, and meningitis/encephalitis caused by CRE is an important sign of the failure of the neurosurgery, which demands the physician's immediate attention.
In wire electrical discharge machining, due to the random distribution of the insulating SiC particles, frequent wire rupture, low machining efficiency and surface quality when the common brass wire ...electrode (BWE) is used to process high-volume content SiCp/Al composite often appears. To address this issue, this paper proposes a new preparation method of zinc coating and surface microstructure on wire electrodes (ZCSMWE). The preparation process of ZCSMWE includes casting, coating, annealing and plastic processing. The experimental results show that, compared with BWE, ZCSMWE can increase material removal rate (MRR) by 16.67%, reduce surface roughness (Ra) by 21.18% and reduce wire rupture under the same discharge parameters. The analysis of workpiece surface topography shows that ZCSMWE can significantly decrease the recast layer and microcrack on the machined surface. The improvement mechanism of ZCSMWE main includes: The low work function zinc can promote the forming of the discharge channel. The vaporization of low boiling temperature zinc can reduce the temperature of the discharge gap and promote the ejecting of workpiece material. In addition, the surface microstructure on ZCSMWE can make the discharge spark more uniformly distributed and increase the proportion of the effective discharge, which contributes to making the discharge crater on the workpiece and wire electrode shallower and more uniform. The surface microstructure on ZCSMWE can also effectively improve the dielectric circulation, which can promote discharge debris to be expelled out and reduce the temperature in the discharge gap. Then, the wire rupture and microcracks on the workpiece surface can be reduced.
The early diagnosis of prostate cancer is very vital for the improvement of patient survival chances. The content of prostate specific antigen (PSA) in serum is closely related to the status of the ...prostate cancer. We report a fluorescence bioassay, capable of detecting PSA in a non-enzymatic and label-free manner. PSA gives rise to the structural change of a hairpin, consequently triggering the hybridization chain reaction and forming a long-nicked double-helix, which is not adsorbed by graphene oxide. GelRed, as the signal indicator, then binds with dsDNA molecule, thereby producing the fluorescence. The established bioassay has the merits of simple operation, favorable cost-to-benefit ratios, good stability, and specificity. Moreover, the detection limit of this assay is as low as 10 pg/mL, and the linearity range is wide-from 100 pg/mL to 200 ng/mL. At the same time, this bioassay can realize the detection of PSA in biological samples (human serum, saliva, and urine). Therefore, the bioassay provides a potential means for the early diagnosis of prostate cancer.
PDF
