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 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.
Polymeric micelle systems for drug delivery, monitor and chemotherapy have gained significant attention, and reductive polymeric micelle systems have become particularly attractive due to their ...controlled release behavior without additional assistance. However, there are challenges in accurately controlling drug and probe release from the nanoparticles and determining the loading content of drug and probe. To address these issues, we have developed a reduction-responsive Pt(IV) prodrug-based polymeric delivery system that can be dynamically monitored using aggregation-induced emission luminogens (AIE) based bioprobes. These polymeric micelle can self-assemble into nanoparticles and release both bio-active Pt(II) drug and bio-probe upon reduction activation. TPE molecules released in the inner endo/lysosomal microenvironment aggregate and fluoresce upon irradiation, thus allowing real-time tracking of drug biodistribution without additional contrast agents. Advantages of this system include position-specific chemical bond cleavage, control of platinum content, and monitoring of drug reduction and biodistribution.
This study used the two-step floating catchment area method and potential model to calculate facility accessibility and potential service scope of public health infrastructure distribution, and to ...evaluate its spatial equity. We applied the Gini coefficient to measure the spatial equilibrium at each level of public health infrastructure in Doumen District, Guangdong, China, from different perspectives. The following results were obtained: (1) Significant spatial differences were observed in the accessibility of public health facilities among different levels; the higher the health facility level, the greater the difference in spatial accessibility. Spatial differences in the accessibility of public health infrastructure at the primary level and higher were distributed in a block-like pattern, while spatial differences in the accessibility of rural health stations were distributed in a circular pattern. Administrative villages tended to have the highest and lowest accessibility of tertiary and secondary hospitals, but not of primary hospitals and rural health stations. The frequencies for administrative villages with the highest and lowest accessibility were 32.8% and 49.6% of the total number of villages in the district, respectively, for tertiary hospitals; 39.2% and 48.8% for secondary hospitals; 19.2% and 24.8% for primary hospitals; 16.8% and 21.6% for rural health stations. (2) The potential service scope was spatially dissociative for tertiary hospitals, and differed more significantly in terms of space for secondary hospitals; the potential service scope of the two overlapped. The potential service scope of primary hospitals was relatively balanced, with strong spatial continuity, while that of rural health service centers was spatially fragmented. The service scope of rural health service centers was mostly consistent with their respective village-level administrative divisions. (3) The higher the level of public health infrastructure, the less balanced its spatial layout. Conversely, the lower the level of public health infrastructure, the more balanced its spatial layout.
•Design of MEMS heart sound sensor based on bionics.•An acoustic packaging method of bionic MEMS heart sound sensor based on acoustic impedance matching.•A bionic MEMS heart sound sensor with high ...sensitivity, wide working bandwidth and linearity.
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Based on the sound pickup mechanism of the three-dimensional ciliary bundle structure of human ear hair cells, this paper proposed a bionic MEMS heart sound sensor. First, the acoustic sensing principle of the bionic microstructure is analyzed and optimized by theoretical analysis and finite element simulation methods. Then the prepared sensor was acoustically encapsulated and experimentally tested. Finally, the dynamic periodic characteristics of the measured heart sound signal were obtained through data analysis, and the validity of the measured heart sound signal was verified. The results show that the optimized bionic MEMS heart sound sensor features high sensitivity, wide working bandwidth, good low frequency characteristics and small size, and can effectively suppress the interference of environmental noise on the sensor. The sensitivity of the sensor reaches − 189.5 dB@500 Hz, the working bandwidth is 10–800 Hz, and the signal-to-noise ratio is 29.08 dB. The sensor can be applied to the field of heart sound auscultation, and is of great significance for the effective acquisition of heart sound signals and the non-destructive diagnosis of cardiovascular diseases.
Aroma, berry firmness and berry shape are three main quality traits in table grape production, and also the important target traits in grapevine breeding. However, the information about their genetic ...mechanisms is limited, which results in low accuracy and efficiency of quality breeding in grapevine. Mapping and isolation of quantitative trait locus (QTLs) based on the construction of genetic linkage map is a powerful approach to decipher the genetic determinants of complex quantitative traits.
In the present work, a final integrated map consisting of 3411 SLAF markers on 19 linkage groups (LGs) with an average distance of 0.98 cM between adjacent markers was generated using the specific length amplified fragment sequencing (SLAF-seq) technique. A total of 9 significant stable QTLs for Muscat flavor, berry firmness and berry shape were identified on two linkage groups among the hybrids analyzed over three consecutive years from 2016 to 2018. Notably, new stable QTLs for berry firmness and berry shape were found on LG 8 respectively for the first time. Based on biological function and expression profiles of candidate genes in the major QTL regions, 3 genes (VIT_08s0007g00440, VIT_08s0040g02740 and VIT_08s0040g02350) related to berry firmness and 3 genes (VIT_08s0032g01110, VIT_08s0032g01150 and VIT_08s0105g00200) linked to berry shape were highlighted. Overexpression of VIT_08s0032g01110 in transgenic Arabidopsis plants caused the change of pod shape.
A new high-density genetic map with total 3411 markers was constructed with SLAF-seq technique, and thus enabled the detection of narrow interval QTLs for relevant traits in grapevine. VIT_08s0007g00440, VIT_08s0040g02740 and VIT_08s0040g02350 were found to be related to berry firmness, while VIT_08s0032g01110, VIT_08s0032g01150 and VIT_08s0105g00200 were linked to berry shape.
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