Insight into BDD electrochemical oxidation of florfenicol in water: Kinetics, reaction mechanism, and toxicity.

Antibiotics in the environment provoke serious consequences on living beings and can be effectively remediated by prominent advanced oxidation process. In this study, electrochemical advanced oxidation treatment in a lab-scale reactor for the degradation of florfenicol (FLO) was studied with the aid of boron-doped diamond anode (BDD). The results exhibited that the FLO degradation follows pseudo-first-order kinetics. As the current intensity rose from 60 mA to 250 mA, the FLO removal efficiency increased and the corresponding reaction rate constant increased from 0.0213 to 0.0343 min-1, which was likely due to the more efficient participation of free hydroxyl radical (•OH) generated at the BDD anode. Faster degradation and higher mineralization of electrolyzed FLO solution were achieved at higher current intensity as well as in higher SO42- concentration medium, as a consequence of catalytic participation of oxidants (free •OH as well as sulfate radical (SO4•-) and persulfate (S2O82-)). The increase in FLO concentration from 30 to 50 mg L-1 resulted in a reaction rate constant decrease (from 0.0235 to 0.0178 min-1). Eight transformation by-products (m/z = 372.99, 359.8, 338.0, 324.04, 199.00, 185.02, 168.99 and 78.989) and three inorganic ions (NO3-, Cl- and F-) were analyzed by UPLC‒Q‒TOF‒MS/MS and Ion‒chromatography, respectively. The Vibrio fischeri bioluminescence inhibition revealed an increase of toxicity during the electrochemical oxidation that could be attributed mostly to the generated organic chlorinated by-products (m/z = 372.99, 359.8) and inorganic species (ClO2- and ClO3-).

Unsupervised Feature Selection via Orthogonal Basis Clustering and Local Structure Preserving.

Due to the "curse of dimensionality" issue, how to discard redundant features and select informative features in high-dimensional data has become a critical problem, hence there are many research studies dedicated to solving this problem. Unsupervised feature selection technique, which does not require any prior category information to conduct with, has gained a prominent place in preprocessing high-dimensional data among all feature selection techniques, and it has been applied to many neural networks and learning systems related applications, e.g., pattern classification. In this article, we propose an efficient method for unsupervised feature selection via orthogonal basis clustering and reliable local structure preserving, which is referred to as OCLSP briefly. Our OCLSP method consists of an orthogonal basis clustering together with an adaptive graph regularization, which realizes the functionality of simultaneously achieving excellent cluster separation and preserving the local information of data. Besides, we exploit an efficient alternative optimization algorithm to solve the challenging optimization problem of our proposed OCLSP method, and we perform a theoretical analysis of its computational complexity and convergence. Eventually, we conduct comprehensive experiments on nine real-world datasets to test the validity of our proposed OCLSP method, and the experimental results demonstrate that our proposed OCLSP method outperforms many state-of-the-art unsupervised feature selection methods in terms of clustering accuracy and normalized mutual information, which indicates that our proposed OCLSP method has a strong ability in identifying more important features.

Study on removal of phosphorus as struvite from synthetic wastewater using a pilot-scale electrodialysis system with magnesium anode.

Struvite precipitation may become ineffective in removing phosphorus due to the low concentration of phosphate in the liquid. In this study, electrolysis with a magnesium anode was applied to recovering phosphorus and ammonia as struvite from wastewater. A novel electrodialysis process (ED) with a magnesium anode was developed, and its feasibility to treat synthetic wastewater with low phosphate concentration was demonstrated in a pilot-scale experimental system. To achieve high phosphate removal efficiency in the product stream, the optimal initial pH and flow rate were found to be 8.8 and 200 L h-1, respectively, for the ED system at a constant current of 0.1 A. The pilot-scale ED system under the consecutive batch mode removed 65% phosphate from the synthetic wastewater containning 10 mg L-1P, and the phosphate concentration in the product stream was kept at 30 mg L-1 after 280 min. The running cost of the ED system was estimated to be $31.27 kg-1 P for synthetic wastewater with 10 mg L-1 P, mainly resulting from the cost of the loss of the magnesium anode. The precipitates generated from the product stream were confirmed as struvite by XRD analysis.

Fast start-up strategies of MBBR for mariculture wastewater treatment.

Moving bed biofilm reactor (MBBR) is widely used for ammonia removal in saline recirculating aquaculture systems but often faces a slow start-up problem. The aim of this study was to develop a strategy for the rapid start-up of MBBR treating synthetic mariculture wastewater. Changes in nitrification performance, biofilm characteristics and bacterial community were assessed in response to various start-up strategies: R1 as the control; R2 with step-decrease of inlet NH4+-N; R3 with step-increase of inlet salinity; R4 added with particulate organic matter (POM) and R5 inoculated with nitrifying bacteria. Results show that nitrification was completed on day 63 for R3, 16-18 days faster than the other strategies. The highest protein (28.2 ±â€¯5.1 mg/g·VS) and polysaccharide (59.4 ±â€¯0.4 mg/g·VS) contents were observed in R3, likely linked to the faster biofilm formation. Fourier Transform infrared spectroscopy (FTIR) analysis confirmed the typical constituents of carbohydrates, proteins, lipids and DNA in biofilms. Moreover, along with the biofilm development in R3, the intensity of the peak at 1400 cm-1 (assigned to specific amides) decreased. Pyrosequencing of 16s rRNA revealed that Gammaproteobacteria was the predominating microbial community at class level (35.6%) in R3. qPCR analysis further verified the significantly higher gene copies of amoA (1.57 × 104 copies/µL) and nxrB (5.51 × 103 copies/µL) in R3. Results obtained make the elevated salinity strategy a promising alternative for the rapid nitrification start-up of saline wastewater.

Performance and membrane fouling of a step-fed submerged membrane sequencing batch reactor treating swine biogas digestion slurry.

To identify the performance of step-fed submerged membrane sequencing batch reactor (SMSBR) treating swine biogas digestion slurry and to explore the correlation between microbial metabolites and membrane fouling within this novel reactor, a lab-scale step-fed SMSBR was operated under nitrogen loading rate of 0.026, 0.052 and 0.062 g NH4+-N (gVSS·d)-1. Results show that the total removal efficiencies for NH4+-N, total nitrogen and chemical oxygen demand in the reactor (>94%, >89% and >97%, respectively) were high during the whole experiment. However, the cycle removal efficiency of NH4+-N decreased significantly when the nitrogen loading rate was increased to 0.062 g NH4+-N (gVSS·d)-1. The total removal efficiency of total phosphorus in the step-fed SMSBR was generally higher than 75%, though large fluctuations were observed during the experiments. In addition, the concentrations of microbial metabolites, i.e., soluble microbial products (SMP) and extracellular polymeric substances (EPS) from activated sludge increased as nitrogen loading rate increased, both showing quadratic equation correlations with viscosity of the mixed liquid in the step-fed SMSBR (both R2 > 0.90). EPS content was higher than SMP content, while protein (PN) was detected as the main component in both SMP and EPS. EPS PN was found to be well correlated with transmembrane pressure, membrane flux and the total membrane fouling resistance. Furthermore, the three-dimensional excitation-emission matrix fluorescence spectroscopy results suggested the tryptophan-like protein as one of the main contributors to the membrane fouling. Overall, this study showed that the step-fed SMSBR could be used to treat swine digestion slurry at nitrogen loading rate of 0.052 g NH4+-N (gVSS·d)-1, and the control strategy of membrane fouling should be developed based on reducing the tryptophan-like PN in EPS.

Pi (Spleen)-deficiency syndrome in tumor microenvironment is the pivotal pathogenesis of colorectal cancer immune escape.

Cancer immunoediting consists of three sequential phases: elimination, equilibrium, and escape. For colorectal adenoma-carcinoma sequence, the adenoma dysplastic progression may represent an equilibrium phase and the cancer stage as escape phase. Immune system eliminates transformed enterocytes by destroying them at first, sculpts them at the same time and selects the variants subsequently that are no longer recognized and insensitive to immune effectors, and finally induces immunosuppressive state within the tumor microenvironment that facilitates immune escape and tumor outgrowth. Immunosuppression and inflammation are the two crucial features of Pi (Spleen)-deficiency. Classic quotations, immune evidence and clinical observations suggest that Spleen (but not other organs) deficiency is the key pathogenesis of colorectal cancer (CRC) microenvironment. Weakness of old age, immunosuppressive cytokines from chronic inflammation, tumor-derived immunosuppressive factors and surrendered immune cells-regulatory T cells, myeloid-derived suppressor cells and tumor associated macrophages (TAMs) constitutes CRC microenvironment of Pi-deficiency. Furthermore, excess in superficiality, such as phlegm stagnation, blood stasis and toxin accumulation are induced by chronic inflammation on the basis of asthenia in origin, an immunosuppressive state. Great masters of Chinese medicine emphasize that strengthen Pi is the chief therapeutic principle for CRC which receives good therapeutic effects. So, Pi-deficiency based syndrome is the pivotal pathogenesis of tumor microenvironment. The immunosuppressive microenvironment facilitates immune escape which play an important role in the transition from adenoma to adenocarcinoma. There are some signs that strengthen Pi based treatment has potential capacity to ameliorate tumor environment. It might be a novel starting point to explore the mechanism of strengthen Pi based therapy in the prevention and treatment of CRC through regulation of tumor environment and immunoediting.

Shenling Baizhu San supresses colitis associated colorectal cancer through inhibition of epithelial-mesenchymal transition and myeloid-derived suppressor infiltration.

BACKGROUND: Shenling Baizhu San (SBS) is a well-known and classical Chinese medicine formula. It has been used for treatment of gastrointestinal disorders for about nine hundred years. Recent reports showed that it was effective in curing colitis and ameliorating the major manifestations of postoperational colorectal cancer (CRC). This study was to evaluate the effects of SBS on azoxymethane (AOM) and dextran sodium sulfate (DSS) induced colitis associated CRC (caCRC) and to analyze the underlying mechanism of SBS in preventing CRC. METHODS: The colon tissue of mice in different group was determined by immunohistochemistry and western blot. TGF-ß1 in serum was measured by ELISA. Myeloid-derived suppressor cells (MDSCs) were identified by flow cytometry and immunohistochemistry. RESULTS: The formed neoplasms phenotypically resembled human caCRC with upregulated ß-catenin, p53 and proliferating cell nuclear antigen (PCNA). SBS treatment reduced the death rate of mice and decreased the incidence and multiplicity of colonic neoplasms. SBS decreased the number of MDSCs and the level of transforming growth factor ß1 (TGF-ß1). SBS alleviated epithelial mesenchymal transition (EMT) through downregulating N-cadherin (N-cad), Vimentin, Fibronectin, Snail, and upregulating E-cadherin (E-cad). It reduced the activation of Wnt5a and EMT induced by TGF-ß1. CONCLUSIONS: SBS reduced the death rate through decreasing the incidence and multiplicity of colonic tumors. SBS lowered MDSCs infiltration and inhibited TGF-ß1 induced EMT to exert its anti-caCRC effects.

ShaoYao decoction ameliorates colitis-associated colorectal cancer by downregulating proinflammatory cytokines and promoting epithelial-mesenchymal transition.

BACKGROUND: Shaoyao decoction (SYD) is a traditional Chinese medicine prescription formulated by Liu Wan-Su, a master of traditional Chinese medicine in Jin-Yuan Dynasty. SYD is effective in treating ulcerative colitis. Paeonol, a component of SYD, inhibits colorectal cancer (CRC) cell proliferation and induces CRC cell apoptosis. In this study, azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colitis-associated CRC (caCRC) model and CRC cell lines were used to examine the effects of SYD on CRC in vivo and in vitro. METHODS: A translational medicine strategy based on phytomics quality control was adopted. Liquid chromatography was employed for the chemical characterization and chemical fingerprinting of SYD. Protein expression and macrophage existence were determined by immunohistochemistry and western blot. Serum cytokines were quantified by Luminex assay. RESULTS: AOM/DSS-induced caCRC phenotypically resembled human caCRC. SYD significantly increased the survival rate of the mice, ameliorated the general well-being of the mice, and reduced the incidence and multiplicity of colonic neoplasms. SYD inhibited epithelial-mesenchymal transition (EMT), as indicated by upregulated epithelia cadherin and downregulated neuronal cadherin, fibronectin, vimentin, and transcription factor Snail. SYD reduced the expression levels of serum interleukin 1ß, interleukin-6, tumor necrosis factor α, tumor-associated macrophages, and p65. These results showed that SYD can attenuate proinflammatory cytokines and inhibit EMT. CONCLUSIONS: SYD ameliorates caCRC by suppressing inflammation and inhibiting EMT. SYD might be an alternative therapy for caCRC.