Caffeic acid accelerated the Fe(II) reinvention in Fe(III)/PMS system for bisphenol A degradation: Oxidation intermediates and inherent mechanism.

Fe(II)-catalyzed PMS process was widely used in the degradation of refractory pollutants in wastewater, while its performance was restricted by the slow regeneration efficiency of Fe(II). Herein, caffeic acid (CFA), a representative of hydroxycinnamic acids, was introduced into Fe(III)/PMS system to accelerate the transformation of Fe(III) to Fe(II) and promote the removal of bisphenol A (BPA). Under optimum condition of 0.1 mM CFA, 0.05 mM Fe(III), and 0.5 mM PMS, almost complete removal of BPA can be achieved within 20 min, which was roughly 6.2 times higher than that in Fe(III)/PMS system. As the addition of CFA into Fe(III)/PMS system, pH application range was widened from acidic to alkaline conditions. The reduction and chelation of CFA expedited the Fe(III)/Fe(II) cycle by forming CFA-Fe chelate, thereby facilitating the PMS activation. Based on LC-MS analysis and DFT calculation, the intermediate products of CFA were found to play a decisive role in boosting the regeneration of Fe(II), and the toxicity of these intermediates towards organisms was evaluated by ECOSAR. The alcohol-scavenging and chemical probe tests certified that hydroxyl radical (•OH), sulfate radical (SO4•-), and Fe(IV) coexisted in Fe(III)/CFA/PMS system, and the second-order reaction rate constants of •OH and SO4•- reacted with CFA were calculated to be 3.16✕109 and 2.30✕1010 M-1 s-1, respectively. Two major degradation pathways of BPA, •OH addition and SO4•- induced hydroxylation reaction, were proposed. This work presented a novel green phenolic compound that expedited the Fe(II)-catalyzed PMS activation process for the treatment of organic contaminants.

Internal electric field-assisted copper ions chelated polydopamine/titanium dioxide nano-thin film heterojunctions activate peroxymonosulfate under visible light to catalyze degradation of gatifloxacin: Theoretical calculations and biotoxicity analysis.

The combination of photocatalysis and peroxymonosulfate (PMS) activation is considered effective in treating organic pollutants in water; however, the photocatalysts currently used to activate PMS are primarily in powder form, which cause secondary contamination because they are difficult to recycle. In this study, copper-ion-chelated polydopamine/titanium dioxide (Cu-PDA/TiO2) nanofilm were prepared for PMS activation on fluorine-doped tin oxide substrates using hydrothermal and in-situ self-polymerization methods. The results showed that Cu-PDA/TiO2 + PMS + Vis degraded 94.8% of gatifloxacin (GAT) within 60 min, and the reaction rate constant reached 4.928 × 10-2 min-1, which was 6.25 and 4.04 folds higher than that of TiO2 + PMS + Vis (0.789 × 10-2 min-1) and PDA/TiO2 + PMS + Vis (1.219 × 10-2 min-1), respectively. The Cu-PDA/TiO2 nanofilm is easily recyclable and activates PMS to degrade GAT with no inferior performance, unlike the powder-based photocatalysts, and simultaneously maintains outstanding stability, which is highly suitable for applications in real aqueous environments. Biotoxicity experiments were conducted using E. coli, S. aureus, and mung bean sprouts as experimental subjects, and the results showed that the Cu-PDA/TiO2 + PMS + Vis system had excellent detoxification ability. In addition, a detailed investigation of the formation mechanism of step-scheme (S-scheme) Cu-PDA/TiO2 nanofilm heterojunctions was conducted by density functional theory (DFT) calculations and in-situ X-ray photoelectron spectroscopy (XPS). Finally, a specific process for activating PMS to degrade GAT was proposed, which provides a novel photocatalysts for practical applications in aqueous pollution.

Catalytic oxidation activation of peroxymonosulfate over Fe-Co bimetallic oxides for flurbiprofen degradation.

In this research, FeCo2O4 nanomaterial was successfully synthesized by a typical sol-gel method and conducted as an effective agent for peroxymonosulfate (PMS) activation to eliminate antibiotics flurbiprofen (FLU), a strong nonsteroidal drug. FeCo2O4 nanomaterial was characterized by XRD, TEM, SEM, and XPS. Various characterization results proved that FeCo2O4 held stable spinel structure. The interfering factors including initial pH, PMS concentration, catalyst dosage, inorganic anions, and humic acid on FLU removal were also discussed. The conclusion was that the removal efficiency of FLU reached 98.2% within 120 min after adding FeCo2O4 (0.4 g L-1) and PMS (3 mM). The optimal pH for FLU degradation was the initial pH of 6.5; too acidic or alkaline was not conductive to the degradation. The existence of HA and Cl- restrained the degradation of FLU, and HCO3- promoted the removal, while the influence of NO3- and SO42- could not be considered. The radical scavenging experiment confirmed that •OH, O2•-, and SO4•- participated in FLU removal and SO4•- functioned a leading role. FeCo2O4 showed high efficiency for PMS activation in pH range of 3.0 to 10.0. After the fourth cycle operation, the FLU removal rate exceeded 76.9%, and the Co leaching rate was low during the catalytic reaction. This study shows that FeCo2O4 nanomaterial is an efficient and environment-friendly catalyst, which can be applied for PMS activation to remove organic pollutants in water.

Degradation of antiviral drug acyclovir by thermal activated persulfate process: Kinetics study and modeling.

Pharmaceutical and personal care products (PPCPs) pose a great threat to water environment security. In this study, acyclovir (ACV) was efficiently degraded by thermally activated persulfate (TAP) system. The ACV degradation increased with rising reaction temperature and persulfate dosage. With the existence of inorganic anions and humic acid, ACV removal was retarded to varying degrees. Under strong alkaline condition, it was observed that the degradation of ACV was significantly inhibited. In addition, Kintecus software was employed to simulate ACV removal and achieved a good fit with the experimental results. The contribution rates of main reactive radicals under acidic, neutral, and alkaline conditions were investigated, and the contribution of hydroxyl radical (⋅OH) increased significantly under alkaline condition. The main active species were identified as sulfate radical (SO4⋅-) and ⋅OH through quenching experiment, and the second-order reaction rate constants of SO4⋅- and ∙OH reacted with ACV were calculated to be 9.17 × 109 M-1 s-1 and 2.74 × 109 M-1 s-1, respectively. The main degradation pathways included addition of free radicals, oxidation of branch chain and ring opening. The acute and chronic toxicity of intermediates to organisms predicted by ECOSAR were significantly reduced compared with that of ACV.

Colorectal cancer occurrence and treatment based on changes in intestinal flora.

Colorectal cancer (CRC) is the most common cancer in the world, and its incidence has been increasing in recent years. The occurrence of CRC is believed to be related to a variety of factors. Epidemiological data indicate that CRC is mainly affected by environmental factors, eating habits, physical activity and genetic factors. As a newly recognized functional component, the intestinal microbiota plays important roles in preventing CRC formation and maintaining intestinal immunity. In this review, we summarize the mechanisms by which the gut microbiota causes CRC through alterations to immune function, focusing on the mechanisms by which intestinal microbial dysfunction promotes CRC. Furthermore, we describe the changes in the intestinal flora observed in CRC and their potential for CRC treatment with the goal of facilitating future research on the roles of the intestinal flora.

IGF2-AS knockdown inhibits glycolysis and accelerates apoptosis of gastric cancer cells through targeting miR-195/CREB1 axis.

Dysregulation of long non-coding RNA (lncRNA) insulin growth factor 2 antisense (IGF2-AS) is being found to have relevance to tumorigenesis, including gastric cancer (GC). The purpose of this study was to further explore the detailed role and molecular mechanism of IGF2-AS in GC progression. The expression levels of IGF2-AS, miR-195 and cAMP responsive element binding protein 1 (CREB1) mRNA were assessed by qRT-PCR. Glucose consumption and lactate production were determined using a corresponding Commercial Assay Kit. Hexokinase 2 (HK2) and CREB1 protein levels were detected using western blot. Cell apoptosis was determined by flow cytometry. The targeted interaction between miR-195 and IGF2-AS or CREB1 was validated using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Our data revealed that IGF2-AS was upregulated in GC tissues and predicted poor prognosis. IGF2-AS knockdown hampered glycolysis and accelerated apoptosis of GC cells. Moreover, IGF2-AS acted as a sponge of miR-195 and CREB1 was a direct target of miR-195. MiR-195 mediated the regulatory effect of IGF2-AS knockdown on GC cell glycolysis and apoptosis. MiR-195 exerted its regulatory effect on GC cell glycolysis and apoptosis by CREB1. Furthermore, IGF2-AS regulated CREB1 expression via sponging miR-195. In conclusion, our study suggested that IGF2-AS knockdown suppressed glycolysis and facilitated apoptosis in GC cells at least partly through sponging miR-195 and modulating CREB1 expression, highlighting a novel therapeutic strategy for GC treatment.

Long non-coding RNA Malat1 activated autophagy, hence promoting cell proliferation and inhibiting apoptosis by sponging miR-101 in colorectal cancer.

BACKGROUND: Long non-coding RNA Malat1 has been widely identified as an oncogene which shows a significant relationship with tumorigenesis in colorectal cancer (CRC). Nonetheless, whether Malat1 participates in the autophagy of colorectal cancer remains unclear. MATERIALS AND METHODS: First, the expression level of Malat1 in 96 pairs of colorectal cancer tissues and four cell lines was detected by qRT-PCR. Subsequently, the autophagy activity in colorectal cancer tissues and cell lines was detected by western blot. Furthermore, the CCK-8 assay and flow cytometry (FCM) were performed to detect the role of autophagy activated by Malat1 in colorectal cancer cell lines. RESULTS: In this study, significantly increased Malat1 expression and autophagy activity were found in colorectal cancer tissues compared with the adjacent normal tissues. Also, the Malat1 level was positively correlated with the expression of LC3-II mRNA in vivo. Moreover, autophagy activation and cell proliferation were significantly facilitated by Malat1 in colorectal cancer cells, while apoptosis decreased. Above all, the inhibition of autophagy by 3-MA not only relieved the Malat1-induced cell proliferation but also promoted the Malat1-induced cell apoptosis. In addition, Malat1 was found to act as an endogenous sponge by directly binding to miR-101 to reduce miR-101. Furthermore, the suppressive effects of miR-101 on the autophagy, proliferation, and apoptosis of CRC were abolished by Malat1. CONCLUSION: Long non-coding RNA Malat1 activated autophagy and promoted cell proliferation, yet inhibited apoptosis by sponging miR-101 in colorectal cancer cells.

[Aspartic Acid Generated in the Process of Chlorination Disinfection By-product Dichloroacetonitrile].

In this study, a method was developed for the determination of dichloroacetonitrile (DCAN) in drinking water by liquid- liquid micro-extraction and gas chromatography/mass spectrometry ( LLE-GC/MS), which used 1,2-dibromopropane as the internal standard and methyl tertiary butyl ether (MTBE) as the extractant for high accuracy. The aspartic acid was used as the precursor of the DCAN formation during chlorination and the influencing factors were evaluated. The formation mechanism of DCAN was also discussed. The results showed that the DCAN amount increased with the increase of pH value under the neutral and acidic conditions, however, the amount of DCAN decreased with the increase of pH value under the alkali condition. And the final amount of DCAN under the alkali condition was much less than that under the neutral and acidic conditions. It was also found that the DCAN amount increased with the increase of chlorine addition, while the temperature in the range of 10-30°C had little influence on the DCAN formation. The formation process of the DCAN from aspartic acid by chlorination included seven steps, such as substitution, decarboxylation, oxidation, etc and ultimately formed DCAN.

[Performance Study of Bromochloracetonitrile Degradation in Drinking Water by Fe/Cu Catalytic Reduction].

The paper used the method of iron copper catalyst reduction to degrade low concentrations of bromochloracetonitrile (BCAN) to lighten the damage to human being, which is a kind of disinfection by-products (DBPs) produced during the chlorination process of drinking water. The removal efficiency of BCAN and its influencing factors were investigated. The mechanism of degradation and kinetics were also explored. The results indicated that iron copper had a greater degradation ability towards BCAN, and the degradation rate of iron copper (mass ratio of 10:1) was 1.5 times that of the zero-valent iron. The removal of BCAN increased obviously with the increase of Fe/Cu dosage. When the initial concentration was set at 20 microg x L(-1), after a reaction time of 150 min, removal of BCAN was improved from 51.1% to 89.5% with the increase of iron copper (mass ratio of 10:1) dosage from 5 g x L(-1) to 10 g x L(-1). The temperature also had great impact on BCAN removal and the removal increased with the increase of temperature. However, BCAN removal did not change a lot with the variation of the initial concentration of BCAN when it was at a low level. The BCAN degradation by iron copper catalytic-reduction followed the first-order kinetics model.

[Formation Mechanism of the Disinfection By-product 1, 1-Dichloroacetone in Drinking Water].

A novel method using methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of the disinfection by-producs 1,1-dichloroacetone (DCAce) by gas chromatography mass spectrometry (GC-MS) was described. The formation process of DCAce and its influencing factors were discussed with L-leucine as the precursor during the chloramination process. The results indicated that the DCAce production increased with the increase of chloramine dosage when the chloramine addition was in the range of 5-30 mg · L(-1). The DCAce amount produced under alkaline condition was higher than those produced under the neutral and acidic conditions, and the DCAce amount reduced with the increase of pH value. Temperature was another important factor that affected the DCAce formation from methylamine especially in the range of 15-35°C , and the higher the temperature, the more the DCAce produced. The formation process of DCAce from L-leucine by chloramine consisted of a series of complicated reactions, including substitution, oxidation, bond breaking, amino diazotization, reduction and so on, and eventually DCAce was formed.

Effect of Helicobacter pylori on cyclooxygenase-2 and inducible nitric oxide synthase in patients with gastric precancerous lesions and its clinical significance.

The aim of this study was to investigate the effect of Helicobacter pylori (Hp) on cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) levels in patients with gastric precancerous lesions and its clinical significance. A total of 114 patients with gastric precancerous lesions, 57 whom were positive for Hp (observation group) and 57 of whom were negative for Hp (control group), were selected for the study. The mRNA levels of COX-2 and iNOS in the gastric precancerous lesion tissue from the two groups of patients were analyzed through the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The protein expression levels of COX-2 and iNOS were analyzed using western blotting and an iNOS kit, respectively. In addition, normal human gastric mucosal GES-1 cells were cultured in vitro and stimulated by Hp for 3, 6, 9 and 12 h. The variations in the mRNA and protein levels of COX-2 and iNOS were then analyzed via RT-qPCR and western blotting. Compared with the control group, the mRNA levels of COX-2 and iNOS in the gastric tissue from the observation group were significantly increased (P<0.05). Furthermore, the expression level of COX-2 and iNOS protein in the gastric tissue from the observation group was significantly higher than that in the tissue from the control group (P<0.05). In vitro analysis showed that the COX-2 and iNOS mRNA and protein levels were significantly increased in the Hp-stimulated normal human gastric mucosal GES-1 cells compared with those in the unstimulated cells. Furthermore, the effect was time-dependent (P<0.05). In conclusion, COX-2 and iNOS are the main inflammatory markers. Hp can induce high expression levels of COX-2 and iNOS in gastric precancerous lesion tissue, which may be associated with the occurrence and development of gastric precancerous lesions.

MicroRNA-137 Contributes to Dampened Tumorigenesis in Human Gastric Cancer by Targeting AKT2.

MiRNAs play important roles in tumorigenesis. This study focused on exploring the effects and regulation mechanism of miRNA-137 on the biological behaviors of gastric cancer. Total RNA was extracted from tissues of 100 patients with gastric cancer and from four gastric cancer cell lines. Expression of miR-137 was detected by real-time PCR from 100 patients. The effects of miR-137 overexpression on gastric cancer cells' proliferation, apoptosis, migration and invasion ability were investigated in vitro and in vivo. The target gene of miR-137 was predicted by Targetscan on line software, screened by dual luciferase reporter gene assay and demonstrated by western blot. As a result, the expression of miR-137 was significant reduced in gastric cancer cell line HGC-27, HGC-803, SGC-7901 and MKN-45 as well as in gastric cancer tissues compared with GES-1 cell or matched adjacent non-neoplastic tissues (p<0.001). The re-introduction of miR-137 into gastric cancer cells was able to inhibit cell proliferation, migration and invasion. The in vivo experiments demonstrated that the miR-137 overexpression can reduce the gastric cancer cell proliferation and metastasis. Bioinformatic and western blot analysis indicated that the miR-137 acted as tumor suppressor roles on gastric cancer cells through targeting AKT2 and further affecting the Bad and GSK-3ß. In conclusion, the miR-137 which is frequently down-regulated in gastric cancer is potentially involved in gastric cancer tumorigenesis and metastasis by regulating AKT2 related signal pathways.

[Formation process of nitrogenous disinfection byproduct trichloronitromethane in drinking water and its influencing factors].

A novel method is described in this paper, which uses methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of nitrogenous disinfection byproduct trichloronitromethane (TCNM) by gas chromatography mass spectrometry (GC-MS). The formation process of TCNM and its influencing factors were evaluated with methylamine as the precursor during chlorination. The results indicated that the TCNM amount produced under alkaline condition was higher than those produced under the neutral and acidic conditions, and the TCNM amount increased with the increase of pH value. It was found that the TCNM amount increased with the increase of chlorine addition when the chlorine dosage was in the range of 2-8 mmol x L(-1). However, the TCNM amount was reduced when the chlorine dosage was enhanced from 8 mmol x L(-1) to 12 mmol x L(-1), under which conditions the concentration of free chlorine was higher and methylamine was turned into nitriles and aldehydes through other reactions. It was also found that the TCNM amount increased with the increase of methylamine addition when the methylamine dosage was in the range of 0.5-4 mmol x L(-1). Temperature was another important factor that affected the TCNM formation from methylamine especially in the range of 10-30 degrees C and the higher the temperature, the more the TCNM amount produced. The formation process of TCNM from methylamine by chlorination was in accordance with the mechanism of an electrophilic reaction, in which HClO and ClO(-) could be used as the electrophilic reagents to attack methylamine and then to form TCNM.

[Analysis of CgGPD gene promoter from Candida glycerinogenes by fluorescent protein].

UNLABELLED: OBJECTIVE; We cloned the promoter of glycerol-3-phosphate dehydrogenase gene(CgGPD) from the Candida glycerinogenes, and studied its functional regulation under high osmotic stress condition. METHODS: We amplified the 950 bp promoter of CgGPD from C. glycerinogenes and the green fluorescent protein gene (gfp) from pCAMBIA1302 vector by PCR and introduced them into a modified vector pYX212-zeocin simultaneously. The recombinant plasmid pYX212-zeocin harboring both the promoter of CgGPD and gene gfp was transformed into S. cerevisiae W303-1A by electroporation. In the medium containing glucose with different concentrations for culturing the recombinant strain S. cerevisiae W303-1A-GFP the green fluorescence was detected by fluorescent microscopy. RESULTS: The gene gfp was functionally expressed under the control of the promoter of CgGPD in S. cerevisiae. Furthermore, the expression of the gene gfp at different level was conducted by the different osmotic stress for the recombinant strain. The green fluorescence was less intensive when the concentration of glucose was low for culturing the recombinant strain, but it became much more intensive when the concentration of glucose increased. CONCLUSION: The promoter of CgGPD is an inducible promoter that can be induced significantly by the high concentration of glucose. The promoter will facilitate further studies on the mechanism of glycerol synthesis from C. glycerinogenes WL2002-5 under osmotic stress conditions.

[Influencing factors on the paranitrobenzoic acid wastewater treatment by chlorine dioxide and activated carbon catalysis-oxidation technology].

The effect of activated carbon dosage, chlorine dioxide dosage, pH value and reaction time on the paranitrobenzoic acid wastewater treatment on chlorine dioxide (ClO2 ) and activated carbon (AC) catalysis-oxidation technology were analyzed, and the efficiencies of the process to remove COD and increase biodegradation capacity (BOD5/COD ratio) were also examined under the optimum conditions as the pretreatment method for paranitrobenzoic acid wastewater with high-concentration. The result showed that the COD removal efficiency of the ClO2/AC catalysis-oxidation system was 10% higher than that of the system with only ClO2 when the COD concentration of paranitrobenzoic acid wastewater was 10 960 mg/L. It was also found that the COD removal was decreased by 35% with the concentration of 7 100 mg/L under the conditions of pH value 4.1, AC dosage 200 g/L, reaction time 30 min and ClO2 dosage 300 mg/L. In addition, the BOD, concentration was increased to 1 810 mg/L and the biodegradability was improved greatly with the BOD5/COD ratio increased from 0.10 to 0.25. In a word, the chlorine dioxide (ClO2) and activated carbon (AC) catalysis-oxidation process is an effective pretreatment method for paranitrobenzoic acid wastewater treatment.

[The affect of the skin stretch on the biomechanical changes of skin].

OBJECTIVE: To investigate the biomechanical changes in skin after employing the skin stretch. METHODS: Skin samples were took from the test group which was stretched for 7 days and control group without stretch respectively in the end of 1, 2, 3, 4, 6, 8 week. The biomechanical index were measured by tensiometer. RESULTS: The mean destroy stress, breaking load, stretch rate of the test group decreased obviously in the first week (the breaking load was increasing at the beginning) and the three index increased subsequently, they reached the climax during the fourth week and turned to normal subsequently to the level of some higher than control group and normal value in the sixth week. The stiffness of the test group reached the climax at the first week and than decreased gradually to the level of some higher than normal value and control group. The biomechanical changes of te control group was not evident by comparing with the test gropu. CONCLUSIONS: Skin stretch may injured the biomechanical property during the early time and turned to normal soon afterwards. The stiffness of the skin was increased and its elasticity was decreased after performing skin stretch.