Accurate detection and analysis of traces of persistent organic pollutants in water is important in many areas, including environmental monitoring and food quality control, due to their long environmental stability and potential bioaccumulation. While conventional analysis of organic pollutants requires expensive equipment, surface enhanced Raman spectroscopy (SERS) has demonstrated great potential for accurate detection of these contaminants. However, SERS analytical difficulties, such as spectral preprocessing, denoising, and substrate-based spectral variation, have hindered widespread use of the technique. Here, we demonstrate an approach for predicting the concentration of sample pollutants from messy, unprocessed Raman data using machine learning. Frequency domain transform methods, including the Fourier and Walsh Hadamard transforms, are applied to sets of Raman spectra of three model micropollutants in water (rhodamine 6G, chlorpyrifos, and triclosan), which are then used to train machine learning algorithms. Using standard machine learning models, the concentration of sample pollutants are predicted with more than 80 percent cross-validation accuracy from raw Raman data. cross-validation accuracy of 85 percent was achieved using deep learning for a moderately sized dataset (100 spectra), and 70 to 80 percent cross-validation accuracy was achieved even for very small datasets (50 spectra). Additionally, standard models were shown to accurately identify characteristic peaks via analysis of their importance scores. The approach shown here has the potential to be applied to facilitate accurate detection and analysis of persistent organic pollutants by surface-enhanced Raman spectroscopy.
Understanding the microwettability of anisotropic molybdenum disulfide crystal is critically important in separation and processing of this material in liquid. In this work, static microwetting properties of MoS2 face (MF) and MoS2 edge (ME) surfaces in water are revealed by the morphology of femtoliter interfacial droplets. The oil droplets with different size distribution were produced from heterogeneous nucleation and growth of nanodroplets during the solvent exchange under controlled flow and solution conditions, and were polymerized for droplet morphology characterization to reveal the relative wettability of the droplets on surfaces. We first demonstrate that the shape of the nanodroplets is responsive to the surface charges on a model pH sensitive substrate of gold coated with a self-assembled monolayer of two types of thiol. The experimental results on MoS2 substrates indicate that (1) oil contact angle of the droplets on ME surface is much larger than that on MF surface at pH 3.0, suggesting that the ME surface is more hydrophilic than MF; (2) the droplets are pinned by the layered nanostructure on MoS2 edge. The fundamental understanding of microwettability elucidated in this study may allow for an improved control of the interaction between anisotropic MoS2 surfaces and the surrounding liquid environment, which is critically important for many industrial applications such as flotation and catalysis systems.
Ein einfacher Weg zu Siliciumoxidfilmen mit senkrechten Mesokanälen: Das Substrat wird in eine Stöber-Lösung getaucht, in der die Siliciumoxidvorstufen hydrolysiert, mit Ammoniak als Katalysator vernetzt und mithilfe eines Tensids auf dem Substrat zu hexagonalen Mesostrukturen zusammengefügt werden, die senkrecht zur Substratoberfläche angeordnet sind. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.
Liquid transport in a confined space can be enhanced via propelling microdroplets. These microdroplets form spontaneously from localized liquid–liquid phase separation as a ternary mixture is diluted by a diffusing poor solvent.
Solvent exchange is a simple process to form oil nanodroplets at solid-liquid interfaces with well-defined location and morphology. In this process, a good solvent of the oil is displaced by a poor solvent, leading to the nucleation and growth of oil droplets from a transient oversaturation at the mixing front. Our recent work has shown that the final volume of the droplets is related to the flow conditions. In this work, we investigate the effects of the type and the composition of solvents on the droplet formation under the same flow conditions. Water nanodroplets were produced by ethanol/cyclohexane (solution A) and cyclohexane (solution B) on a hydrophilic substrate. We found that the droplet size increases first and then decreases with an increase of the initial ethanol concentration in solution A. This is attributed to the phase separation of ethanol-cyclohexane-water; in particular, the composition of solution A on the phase boundary above the Ouzo region. The same reason also contributes to the lower efficiency in droplet formation for a longer alkane. The important implication from this work is that the maximal droplet volume is limited by the phase separation of the solvents used in the solvent exchange.
AIM: To explore the effects of high D-glucose on the mRNA and protein expression of lectin-like oxidized LDL receptor-1 (LOX-1) in endothelial cells and to study the possible mechanism by which diabetes is easily accompanied by vascular diseases. METHODS: Cell morphology was observed with inverted phasecontrast microscope. LOX-1 mRNA was detected by quantitative reverse transcription polymerase chain reaction in vascular epithelial cells cultured with different concentration D-glucose (7 5, 15 or 30 mmol/L) or with the same concentration D-glucose (15 mmol/L) in different time (0, 12, 24, 48, 72 or 96 h), LOX-1 protein expression was also examined by immunohistochemisty. RESULTS: Cells, exposed to high concentration D-glucose, were crude with clear profiles and bright granules in the plasma. Different high concentration D-glucose could induce LOX-1 mRNA expression and the effect of 30 mmol/L glucose on LOX-1 mRNA was the most significant (P0 01). LOX-1 mRNA expression increased with time prolonging and reached its peak at 48 h (P0 01), then decreased. As immunohistochemisty showed, brown granules were located in the cell plasma and the cell membrane even in dendritic structure and there was significant difference between the high glucose and the control. CONCLUSION: High concentration D-glucose induces LOX-1 mRNA expression in a time-and dose-dependent manner. Induced protein exists in the cell plasma and the cell membrane. The effect of D-glucose on LOX-1 may be one of reasons why diabetes is easily accompanied by vascular diseases.
This study aimed to investigate the efficacy of combination of rapamycin, an mammalian target of rapamycin (mTOR) inhibitor for treating rejection after organ transplantation, and oxaliplatin, a third-generation of platinum drug usually used to treat chemoresistant or progressive ovarian cancer, in cisplatin-resistant ovarian carcinoma cells A2780cis.Expressions of mTOR and its target molecules p70S6K and 4E-BP1 were determined in cisplatin-sensitive and -resistant cells A2780 and A2780cis, respectively, using Western blotting. Proliferation of A2780cis exposure to oxaliplatin or oxaliplatin plus rapamycin was examined using MTT assay in vitro as well as a nude mice model in vivo. Cell apoptosis and proapoptosis proteins including caspase-8 and -3 and PARP were determined using flow cytometry and Western blotting.We found that A2780cis cells had partial cross-resistance between cisplatin and oxaliplatin. The levels of phosphorylated mTOR (p-mTOR), p70S6K, and 4E-BP1 were significantly increased in A2780cis cells compared to A2780 cells, which might be implicated in cisplatin-induced chemoresistance. Rapamycin obviously enhanced the inhibitory effect of oxaliplatin on the growth of A2780cis both in vitro and in vivo. Rapamycin slightly induced cell apoptosis but significantly enhanced the effect of oxaliplatin in soliciting apoptosis of A2780cis cells, which might be ascribed to its ability in further increasing the levels of cleaved caspase-8 and -3 and PARP induced by oxaliplatin.These results suggested that combination of oxaliplatin and rapamycin enhanced the antitumour efficacy of oxaliplatin in A2780cis cells and therefore might have a role in treating cisplatin-resistant ovarian carcinoma.
Marine gravity field information has a great significance for the resource, environment and military affairs. As a new way to get marine gravity data, the satellite altimetry technique makes up for what ship measuring means lack. The paper carries out the researches on how altimeter data applied for calculating marine gravity anomaly based on inverse Stokes formula. In the article, the editing of 14-track Jason-1 data over South China Sea for 7 years is for collinear processing and cross-point adjustment. The inverse Stokes formula and fast Flourier transform technique are applied to calculate marine gravity anomaly of the region (0°∼23°N, 103°∼120°E), and to draw gravity anomaly map. Compared with the gravity anomaly by ship observation, RMS is 12.6mGal, and single altimetry satellite has a good precision.
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