Chiral purity is becoming increasingly critical particularly for the pharmaceutical industry. Compared to the conventional techniques, membrane-based separation is promising as an easily scalable, ...efficient, continuous operation. Past studies have proven the efficacy of membranes for such separations, but the knowledge available on such processes remain limited. Since membrane fouling is well acknowledged to be one of the key impediments to more widespread implementation of membrane-filtration processes, this study was targeted at addressing the question of whether a relationship exists between the extents of membrane fouling and chiral purification. Another goal was to provide a more comprehensive understanding of the effect of various operating parameters (namely, chiral concentration, ratio of chiral selector to chiral concentrations, pH, feed medium and cross-flow velocity (CFV)) on the extent of chiral separation. The membrane was a non-chiral-selective polyethersulfone ultrafiltration membrane, the chiral selector was bovine serum albumin (BSA), while the chiral species was D,L-phenylalanine (Phe). Higher Phe concentrations decreased the separation factor and increased flux decline, while the highest separation factor was at an intermediate ratio of BSA to Phe concentration and an intermediate flux decline. Also, an intermediate pH of 9 gave the highest separation factor but extensive flux decline, and phosphate buffered saline (PBS) gave better separation and lesser flux decline than water as the feed medium. Regarding cross-flow velocity, the separation factor increased with CFV and decreased with flux decline. With respect to the relationship between the extents of chiral purification and flux decline, a poor correlation between the two existed, which suggests that improving membrane-based chiral separation requires means to improve the binding between the chiral selector and chiral species, rather than the conventional strategies to mitigate membrane fouling.
•Poor correlation between separation factor and flux decline.•Binding between BSA and L-Phe played important role to enhance chiral separation.•Separation factor increased with cross-flow velocity and decreased with flux decline.•Separation factor and flux decline decreased as Phe concentration increased.•Varying CFV and pH significantly enhanced chiral separation.
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Distant metastasis has been detected in approximately 50% of GIST patients at the first ...diagnosis. The surgical strategy for metastatic GIST with generalized progression (GP) after imatinib therapy remains unclear.
We recruited 15 patients with imatinib-resistant metastatic GIST. They received cytoreductive surgery (CRS) for tumor rupture, intestinal obstruction and gastrointestinal bleeding. We collected clinical, pathological and prognostic data for analyses.
OS and PFS after R0/1 CRS were 56.88 ± 3.47 and 26.7 ± 4.12 months, respectively, when compared with 26 ± 5.35 and 5 ± 2.78 months after R2 CRS (P = 0.002 and P < 0.001, respectively). The OS of patients from the initiation of imatinib in the R0/1 group was 133.90 ± 15.40 months when compared with 59.80 ± 10.98 months in the R2 CRS group. There were two significant grade III complications after 15 operations (13.3%). No patient underwent reoperation. In addition, no perioperative death occurred.
R0/1 CRS is highly probable to provide prognostic benefits for patients with metastatic GIST who experience GP following imatinib treatment. An aggressive surgical strategy for achieving R0/1 CRS can be deemed safe. If applicable, R0/1 CRS should be carefully considered in imatinib-treated patients with GP metastatic GIST.
DNA methylation affects gene expression and maintains genome integrity. The DNA-dependent RNA polymerase IV (Pol IV), together with the RNA-dependent RNA polymerase RDR2, produces double-stranded ...small interfering RNA precursors essential for establishing and maintaining DNA methylation in plants. We determined the cryo–electron microscopy structures of the Pol IV–RDR2 holoenzyme and the backtracked transcription elongation complex. These structures reveal that Pol IV and RDR2 form a complex with their active sites connected by an interpolymerase channel, through which the Pol IV–generated transcript is handed over to the RDR2 active site after being backtracked, where it is used as the template for double-stranded RNA (dsRNA) synthesis. Our results describe a ‘backtracking-triggered RNA channeling’ mechanism underlying dsRNA synthesis and also shed light on the evolutionary trajectory of eukaryotic RNA polymerases.
Understanding the electric double layer is essential for achieving efficient electrochemical energy storage technologies. A conventional solid–liquid electrode interface suffers from serious ...self‐discharge and a narrow voltage window, which makes the development of a solid–solid interface imperative. However, an in‐depth understanding of the electric double layer with a solid–solid interface is lacking. Here, a solid–solid interfacial electric double layer is proposed with excellent electrochemical performance. The solid layer is constructed by the electrochemical decomposition of lithium difluoro(oxalate)borate, which provides a desolvated environment for the establishment of a electric double layer. This makes a stronger interaction between the electrode surface and the ions. Based on this unique property, it is found that the solid–solid interfacial electric double layer has an increased capacitance, which suggests a way to develop high‐energy electrochemical capacitors.
A solid–solid interfacial electric double layer is proposed by a preliminary electrochemical coating. The desolvated environment within the solid–solid interface causes a stronger interaction between the electrode surface and the ions. Based on this unique property, it is found that the solid–solid interfacial electric double layer has an increased capacitance, which suggests a way to develop high‐energy electrochemical capacitors.
As membrane technology becomes more popular for separation and purification in the aqueous phase, the advantages have increasingly attracted attention for organic solvent filtration applications. ...However, although the knowledge base on the inevitable membrane fouling in water is rich by now, the understanding for organic solvents is limited. Accordingly, this study was targeted at providing insights on the fouling behavior of the same colloidal foulant (namely, silica) and microfiltration membrane (namely, Anopore) in four different solvents (namely, DI water, ethanol, hexane and formamide). The direct observation through the membrane (DOTM) technique was used to characterize critical flux (Jcrit), which affirmed the distinctly different values in the four solvents at various Reynolds numbers. The shear-induced diffusion model predicted well for water and formamide only, indicating the model has to be enhanced to account for solvent effects. To quantify the interfacial interactions, the Derjaguin-Landau-Verwey-Overbeek (DLVO) and extended (XDLVO) models were used. Both models agreed in that silica-membrane and silica-silica interactions were the most attractive in hexane, which underlies the immediate membrane fouling and extensive clumping, respectively. For the other three solvents, the relative DLVO interaction energies agreed with the relative Jcrit values at fixed Re, indicating the greater relevance of the DLVO (rather than XDLVO) model and Re (rather than crossflow velocity). Because the greatest silica-silica repulsion in ethanol was mis-predicted by both DLVO and XDLVO models, the solvation film effect was additionally harnessed to provide an explanation. The understanding gained from this study on membrane fouling in organic solvents are expected to be beneficial in the design and operation of such emerging membrane filtration systems.
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•Different critical fluxes of silica in water, ethanol, hexane and formamide.•Shear-induced diffusion models mis-predicted for ethanol and hexane.•Both DLVO and XDLVO models predicted well the severe fouling and clumping in hexane.•Relative DLVO interaction energies agreed with relative Jcrit values at fixed Re.•Solvation film effect provided explanation for increased dispersity in ethanol.
The excitonic relaxation dynamics of perovskite adsorbed on mesoporous thin films of Al2O3 and NiO upon excitation at 450 nm were investigated with femtosecond optical gating of photoluminescence ...(PL) via up‐conversion. The temporal profiles of emission observed in spectral region 670–810 nm were described satisfactorily with a composite consecutive kinetic model and three transient components representing one hot and two cold excitonic relaxations. All observed relaxation dynamics depend on the emission wavelength, showing a systematic time–amplitude correlation for all three components. When the NiO film was employed, we observed an extent of relaxation proceeding through the non‐emissive surface state larger than through the direct electronic relaxation channel, which quenches the PL intensity more effectively than on the Al2O3 film. We conclude that perovskite is an effective hole carrier in a p‐type electrode for NiO‐based perovskite solar cells showing great performance.
Femtosecond optical gating (FOG) technique was employed to investigate the excitonic relaxation mechanism in a NiO‐supported p‐type perovskite. The effect of photoluminescence quenching and the excellent photovoltaic performance were rationalized based on this measurement.
•Reservoir computing models are proposed to predict seven stock market indices.•Random, small-world, and scale-free network topologies are studied.•Proposed models achieve competitive results ...compared to other deep learning models.
Prediction of the financial market price is critical for financial decision-making and market policy-making. Recently, various machine learning and deep learning methods have been adopted to predict financial markets’ movements using historical time series of prices. However, accurate prediction of financial prices is still a long-standing challenge that always calls for new approaches. In this study, a novel machine learning model of reservoir computing is developed to predict stock market indices. The performance of the proposed new model is systematically evaluated using the time series of daily closing prices of seven major international stock market indices including S&P500 Index, New York Stock Exchange Composite, Dow Jones Industrial Average, Nasdaq Composite Index, Financial Times Stock Exchange 100 Index, Nikkei 225 Index, and Shanghai Stock Exchange Index between January 4, 2010, and December 31, 2018 covering 2,272 trading days. The results show that our model outperforms the widely used deep learning methods of long short-term memory and recurrent neural network in most cases. To further evaluate the predictive capability of our model, we compare our model to the other two newly reported deep learning methods in recent studies. Comparative results also show that our model is competitive to those deep learning methods in predicting stock market indices. Our study contributes to the literature by developing novel reservoir computing models for financial market predictions. Meanwhile, our results also provide practical implications for financial practitioners of potential financial applications of reservoir computing in financial time series analysis and predictions.
Fatty liver has become a main problem that causes huge economic losses in many aquaculture modes. It is a common physiological or pathological phenomenon in aquaculture, but the causes and occurring ...mechanism are remaining enigmatic.
Each three liver samples from the control group of allogynogenetic gibel carp with normal liver and the overfeeding group with fatty liver were collected randomly for the detailed comparison of histological structure, lipid accumulation, transcriptomic profile, latent pathway identification analysis (LPIA), marker gene expression, and hepatocyte mitochondria analyses.
Compared to normal liver, larger hepatocytes and more lipid accumulation were observed in fatty liver. Transcriptomic analysis between fatty liver and normal liver showed a totally different transcriptional trajectory. GO terms and KEGG pathways analyses revealed several enriched pathways in fatty liver, such as lipid biosynthesis, degradation accumulation, peroxidation, or metabolism and redox balance activities. LPIA identified an activated ferroptosis pathway in the fatty liver. qPCR analysis confirmed that gpx4, a negative regulator of ferroptosis, was significantly downregulated while the other three positively regulated marker genes, such as acsl4, tfr1 and gcl, were upregulated in fatty liver. Moreover, the hepatocytes of fatty liver had more condensed mitochondria and some of their outer membranes were almost ruptured.
We reveal an association between ferroptosis and fish fatty liver for the first time, suggesting that ferroptosis might be activated in liver fatty. Therefore, the current study provides a clue for future studies on fish fatty liver problems.
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