Simultaneous determination of three strong polarity herbicides in tea by ion chromatography-triple quadrupole mass spectrometry.

Due to lack of chromogenic groups and fluorescence groups, high boiling point, high polarity, low volatility, and small molecular weight of glyphosate, glufosinate and bentazone, the detection of three analyses were limited in all kinds of food. Herein, a method for the simultaneous determination of glyphosate, glufosinate and bentazone in tea by ion chromatography tandem triple quadrupole mass spectrometry (IC-MS) was developed, which is without organic solvent and complex derivatization. The recoveries of three compounds in different teas (black tea, green tea, white tea) ranged from 80.40 % to 107.00 %, and the intraday precision (n = 6) ranged from 0.57 % to 9.90 %, the daytime precision ranged from 1.00 % to 5.30 %, the quantitative limit (LOQ) ranged from 0.36 to 1.30 µg/L, and the detection limit (LOD) ranged from 0.11 to 0.39 µg/L. Furthermore, the detection limit and quantitative limit of glyphosate, glufosinate and bentazone by this method are lower than other methods in real samples. Meanwhile, the established method was successfully applied to determine the terminal residues of the three analytes in twelve tea samples from commercial market. Therefore, this method can provide reliable technical support for the study of residue status in vegetables and fruits.

Distribution characteristics of green tides and its impact on environment in the Yellow Sea.

Large-scale outbreaks of green tides in the Yellow Sea affect the development of local tourism and aquaculture and significantly damage the coastal ecological environment. To study the distribution characteristics of green tides and to explore their impact on the environment, a coupled physical-ecological model (LTRANS-GT) based on the Lagrangian TRANSport model (LTRANS) was constructed in this paper to simulate the growth and dissipation process of Ulva prolifera and to obtain its drift trajectory and biomass. The results show that the tracks of the green tide are mainly divided into three categories, namely, northwestward, northward, and eastward. The green tide biomass showed a single-peak with seasonal variation in most years (entering a rapid proliferation period in May-June, reaching a peak biomass after developing for approximately 30 days, then dying out rapidly and basically disappearing by August), and showed a double-peak only in a few years due to extreme weather effects. In 2017, the biomass of U. prolifera was the lowest, with a maximum wet weight of only 24600 tons, while the largest biomass occurred in 2013, with a maximum wet weight of more than 560,000 tons. The interannual difference in the biomass of U. prolifera was mainly due to its initial biomass and the difference in nutrient concentration in the area where it was located. The year in which U. prolifera absorbed the most dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) was 2013, with absorption values of 3973 tons and 114 tons, respectively; and the year in which U. prolifera absorbed the least DIN and DIP was 2017, with absorption values of 172 tons and 5 tons, respectively. During the period of U. prolifera outbreak, the consumption of DIN and DIP in the sea area where it occurred accounted for approximately 43.65% and 0.6% of the total discharge of the rivers, and 26.86% and 6.1% of the atmospheric deposition, respectively. The impact of green tide outbreaks on the annual nitrogen and phosphorus nutrient budget of the entire Yellow Sea was relatively small, but the impact on the area where U. prolifera grows and decays can not be ignored. In dissipation period, the decay of U. prolifera may make DON and DOP double near Shandong coast.

Weak electro-stimulation promotes microbial uranium removal: Efficacy and mechanisms.

Removal and recovery of uranium from uranium-mine wastewater is beneficial to environmental protection and resource preservation. Reduction of soluble hexavalent U (U(VI)) to insoluble tetravalent uranium (U(IV)) by microbes is a plausible approach for this purpose, but its practical implementation has long been restricted by its intrinsic drawbacks. The electro-stimulated microbial process offers promise in overcoming these drawbacks. However, its applicability in real wastewater has not been evaluated yet, and its U(VI) removal mechanisms remain poorly understood. Herein, we report that introducing a weak electro-stimulation considerably boosted microbial U(VI) removal activities in both synthetic and real wastewater. The U(VI) removal has proceeded via U(VI)-to-U(IV) reduction in the biocathode, and the electrochemical characterization demonstrates the crucial role of the electroactive biofilm. Microbial community analysis shows that the broad biodiversity of the cathode biofilm is capable of U(VI) reduction, and the molecular ecological network indicates that synthetic metabolisms among electroactive and metal-reducing bacteria play major roles in electro-microbial-mediated uranium removal. Metagenomic sequencing elucidates that the electro-stimulated U(VI) bioreduction may proceed via e-pili, extracellular electron shuttles, periplasmic and outer membrane cytochrome, and thioredoxin pathways. These findings reveal the potential and mechanism of the electro-stimulated U(VI) bioreduction system for the treatment of U-bearing wastewater.

Coupled sulfur and electrode-driven autotrophic denitrification for significantly enhanced nitrate removal.

Elemental sulfur (S0)-based autotrophic denitrification (SAD) has gained intensive attention in the treatment of secondary effluent for its low cost, high efficiency, and good stability. However, in practice, the supplementary addition of limestone is necessary to balance the alkalinity consumption during SAD operation, which increases water hardness and reduces the effective reaction volume. In this study, a coupled sulfur and electrode-driven autotrophic denitrification (SEAD) process was proposed with superior nitrate removal performance, less accumulation of sulfate, and self-balance of acidity-alkalinity capacity by regulating the applied voltage. The dual-channel electron supply from S0 and electrodes made the nitrate removal rate constant k in the SEAD process 3.7-5.1 and 1.4-3.5 times higher than that of the single electrode- and sulfur-driven systems, respectively. The S° contributed to 75.3%-83.1% of nitrate removal and the sulfate yield during SEAD (5.67-6.26 mg SO42-/mg NO3--N) was decreased by 17%-25% compared with SAD. The S0 particle and electrode both as active bio-carriers constructed collaborative denitrification communities and functional genes. Pseudomonas, Ralstonia and Brevundimonas were the dominant denitrifying genera in S0 particle biofilm, while Pseudomonas, Chryseobacterium, Pantoea and Comamonas became dominant denitrifying genera in the cathode biofilm. The narG/Z/H/Y/I/V, nxrA/B, napA/B, nirS/K, norB/C and nosZ were potential functional genes for efficient nitrate reduction during the SEAD process. Metagenomic sequencing indicated that S0 as an electron donor has greater potential for complete denitrification than the electrode. These findings revealed the potential of SEAD for acting as a highly efficient post denitrification process.

Electrochemical removal and recovery of uranium: Effects of operation conditions, mechanisms, and implications.

Removing and recovering uranium (U) from U-mining wastewater would be appealing, which simultaneously reduces the adverse environmental impact of U mining activities and mitigates the depletion of conventional U resources. In this study, we demonstrate the application of a constant-voltage electrochemical (CVE) method for the removal and recovery of U from U-mining wastewater, in an ambient atmosphere. The effects of operation conditions were elucidated in synthetic U-bearing water experiments, and the cell voltage and the ionic strength were found to play important roles in both the U extraction kinetics and the operation cost. The mechanistic studies show that, in synthetic U-bearing water, the CVE U extraction proceeds exclusively via a single-step one-electron reduction mechanism, where pentavalent U is the end product. In real U-mining wastewater, the interference of water matrices led to the disproportionation of the pentavalent U, resulting in the formation of tetravalent and hexavalent U in the extraction products. The U extraction efficacy of the CVE method was evaluated in real U-mining wastewater, and results show that the CVE U extraction method can be efficient with operation costs ranging from $0.55/kgU ~ $64.65/kgU, with varying cell voltages from 1.0 V to 4.0 V, implying its feasibility from the economic perspective.

Efficient removal of heavily oil-contaminated soil using a combination of fenton pre-oxidation with biostimulated iron and bioremediation.

Crude oil contamination severely deteriorates soils quality. Bioremediation utilizing soil indigenous organisms could be employed to decompose petroleum hydrocarbons thanks to its low cost and minor environmental disturbance. However, slow kinetics limit the successful application of this biotechnique. Pretreating oil-contaminated soils with Fenton pre-oxidation could accelerate the subsequent bioremediation process. This study was to explore the mechanisms behind the rapid propagation of indigenous petroleum-degrading bacteria (IPDB) and the efficient degradation of total petroleum hydrocarbons (TPH) in soil after Fenton pre-oxidation with biostimulated iron. Biostimulated iron and non-biostimulated iron were used in the experiments, where Fenton pre-oxidation was combined with the bioremediation of oil-contaminated soil (TPH = 13221 mg/kg). Although the amount of Fenton pre-oxidized TPH (3331-3775 mg/kg) was similar with biostimulated and non-biostimulated irons, the biodegradation of TPH after Fenton pre-oxidation with biostimulated iron (5840 mg/kg) was much higher than that with non-biostimulated iron (3034-4034 mg/kg). Moreover, abundant nutrients and a high population of residual IPDB were found after Fenton pre-oxidation with biostimulated iron, which benefited stable consumption of NH3-N and dissolved organic carbon (DOC) by IPDB during the subsequent bioremediation. However, Fenton pre-oxidation with non-biostimulated iron either resulted in greater damage to IPDB or produced fewer nutrients, thereby failing to ensure the continuous propagation of IPDB during the subsequent bioremediation. Therefore, we propose that Fenton pre-oxidation with biostimulated iron should be applied to heavily oil-contaminated soils prior to bioremediation.

Enhancement of growth, antioxidative status, nonspecific immunity, and disease resistance in gibel carp (Carassius auratus) in response to dietary Flos populi extract.

This study investigated the effects of dietary Flos populi extract (FPE) on the growth, antioxidation capability, innate immune response, and disease resistance in gibel carp. A total of 480 fish were fed with five different diets containing 0, 0.5, 1.0, 1.5, or 2.0 g kg-1 FPE (designated as control, D0.5, D1.0, D1.5, or D2.0 groups) for 45 days. The fish were challenged with A. hydrophila after the feeding trial. Compared with the control, the feed efficiency (FE), weight gain (WG), final body weight (FBW), and specific growth rate (SGR) were significantly improved in groups D1.0 and D1.5. Dietary FPE significantly increased serum superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities, as well as glutathione (GSH) content. The contents of protein carbonyl (PCC) and malondialdehyde (MDA) in serum decreased significantly. Additionally, FPE supplementation in diets resulted in significant improvement in serum lysozyme (LZM) and myeloperoxidase (MPO) activities, as well as immunoglobulin M (IgM) and complement 3 (C3) concentrations. The hepatic antioxidant enzymes (CAT and SOD) activities increased, whereas content of MDA decreased in fish treated with dietary FPE than those of control both pre- and post-challenged. After 12 h-challenge, an obvious downregulation of hepatic Kelch-like-ECH-associated protein 1 (Keap1), splenic tumor necrosis factor-α (TNF-α), interleukin (IL)-8, IL-1ß, and toll-like receptor 2 (TLR2) mRNA levels was observed in fish treated with dietary FPE, whereas hepatic Nrf2 transcription level was upregulated compared to the control. Furthermore, compared to group D0.5, higher relative percent survival (RPS) was observed in gibel carp fed dietary 1.0-2.0 g/kg FPE. Our results reveal that FPE supplemented diet has a stimulatory effect on antioxidant capacity and nonspecific immune response, along with improved growth performance and enhanced resistance against A. hydrophila infection in juvenile gibel carp.

Paeoniflorin Alleviates Abnormalities in Rats with Functional Dyspepsia by Stimulating the Release of Acetylcholine.

INTRODUCTION: Paeoniflorin is a main active component in traditional Chinese medicine. Paeoniae alba radix is widely used as a spasmolytic and pain-relieving agent for abdominal spasmodic pain. Functional dyspepsia (FD) is characterized by pain or burning in the epigastrium, fullness, bloating and nausea. However, limited information is available about the effect of paeoniflorin on FD. MATERIALS AND METHODS: In this study, iodoacetamide or clonidine-induced FD rat models were established to investigate the impacts of paeoniflorin on FD induced by different pathophysiologic disturbances. RESULTS: We found the therapeutic effect of paeoniflorin through assessing the gastric emptying, gastric accommodation and visceral hypersensitivity. This function of paeoniflorin was related to the release of acetylcholine (ACh), which was accompanied by reduced acetylcholinesterase (AchE) activity in stomach and hypothalamus. Paeoniflorin administration inhibited the cyclo-oxygenase-2 (COX-2) expression and increased the level of ghrelin in the stomach. Besides, the levels of occludin and ZO-1 were elevated in the duodenum from paeoniflorin-treated rats, suggesting the impaired duodenal barrier was ameliorated. DISCUSSION: These results indicate that paeoniflorin possesses the ability to alleviate functional dyspepsia.

Effect of Aging on the Stability of Microbially Reduced Uranium in Natural Sediment.

Reductive immobilization of uranium has been explored as a remediation strategy for the U-contaminated subsurface. Via the in situ biostimulation of microbial processes, hexavalent U is reduced to less soluble tetravalent species, which are immobilized within the sediment. Although the mineral uraninite (UO2) was initially considered the dominant product of biological reduction, non-crystalline U(IV) species (NCU(IV)) are found to be abundant in the environment despite their greater susceptibility to oxidation and remobilization. However, it has been recently proposed that, through aging, NCU(IV) might transform into UO2, which would potentially enhance the stability of the reduced U pool. In this study, we performed column experiments to produce NCU(IV) species in natural sediment mimicking the environmental conditions during bioremediation. Bioreduced sediment retrieved from the columns and harboring NCU(IV) was incubated in static microcosms under anoxic conditions to allow the systematic monitoring of U coordination by X-ray absorption spectroscopy (XAS) over 12 months. XAS revealed that, under the investigated conditions, the speciation of U(IV) does not change over time. Thus, because NCU(IV) is the dominant species in the sediment, bioreduced U(IV) species remain vulnerable to oxidation and remobilization in the aqueous phase even after a 12-month aging period.

Oxygen-independent combined photothermal/photodynamic therapy delivered by tumor acidity-responsive polymeric micelles.

Tumor hypoxia strikingly restricts photodynamic therapy (PDT) efficacy and limits its clinical applications in cancer therapy. The ideal strategy to address this issue is to develop oxygen-independent PDT systems. Herein, the rationally designed tumor pH-responsive polymeric micelles are devised to realize oxygen-independent combined PDT and photothermal therapy (PTT) under near-infrared light (NIR) irradiation. The triblock copolymer, poly(ethylene glycol)-b-poly(ε-caprolactone)-b-poly(2-(piperidin-1-yl)ethyl methacrylate) (PEG-b-PCL-b- PPEMA), was prepared to co-encapsulate cypate and singlet oxygen donor (diphenylanthracene endoperoxide, DPAE) via self-assembly to obtain the micellar delivery system (C/O@N-Micelle). C/O@N-Micelle showed remarkable tumor accumulation and improved cellular internalization (2.1 times) as the pH value was changed from 7.4 during blood circulation to 6.8 in tumor tissues. The micelles could produce a potent hyperthermia for PTT of cypate under 808 nm NIR irradiation, which simultaneously induced thermal cycloreversion of DPAE generating abundant singlet oxygen for PDT without participation of tumor oxygen. Finally, the photothermally triggered PDT and PTT combination achieved efficient tumor ablation without remarkable systemic toxicity in an oxygen-independent manner. This work represents an efficient strategy for oxygen-independent combined PDT and PTT of cancers under NIR irradiation through co-encapsulation of cypate and DPAE into tumor pH-responsive polymeric micelles.

Insights into the Roles of Midazolam in Cancer Therapy.

With its high worldwide mortality and morbidity, cancer has gained increasing attention and novel anticancer drugs have become the focus for cancer research. Recently, studies have shown that most anesthetic agents can influence the activity of tumor cells. Midazolam is a γ-aminobutyric acid A (GABAA) receptor agonist, used widely for preoperative sedation and as an adjuvant during neuraxial blockade. Some studies have indicated the potential for midazolam as a novel therapeutic cancer drug; however, the mechanism by which midazolam affects cancer cells needs to be clarified. This systematic review aims to summarize the progress in assessing the molecular mechanism of midazolam as an anticancer agent.

Products of in Situ Corrosion of Depleted Uranium Ammunition in Bosnia and Herzegovina Soils.

Hundreds of tons of depleted uranium (DU) ammunition were used in previous armed conflicts in Iraq, Bosnia and Herzegovina, and Serbia/Kosovo. The majority (>90%) of DU penetrators miss their target and, if left in the environment, corrode in these postconflict zones. Thus, the best way to understand the fate of bulk DU material in the environment is to characterize the corrosion products of intact DU penetrators under field conditions for extended periods of time. However, such studies are scarce. To fill this knowledge gap, we characterized corrosion products formed from two intact DU penetrators that remained in soils in Bosnia and Herzegovina for over seven years. We used a combination of X-ray powder diffraction, electron microscopy, and X-ray absorption spectroscopy. The results show that metaschoepite (UO3(H2O)2) was a main component of the two DU corrosion products. Moreover, studtite ((UO2)O2(H2O)2·2(H2O)) and becquerelite (Ca(UO2)6O4(OH)6·8(H2O)) were also identified in the corrosion products. Their formation through transformation of metaschoepite was a result of the geochemical conditions under which the penetrators corroded. Moreover, we propose that the transformation of metaschoepite to becquerelite or studtite in the DU corrosion products would decrease the potential for mobilization of U from corroded DU penetrators exposed to similar environments in postconflict areas.

Uranium isotopes fingerprint biotic reduction.

Knowledge of paleo-redox conditions in the Earth's history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth's crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. Additionally, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.

Geochemical control on uranium(IV) mobility in a mining-impacted wetland.

Wetlands often act as sinks for uranium and other trace elements. Our previous work at a mining-impacted wetland in France showed that a labile noncrystalline U(IV) species consisting of U(IV) bound to Al-P-Fe-Si aggregates was predominant in the soil at locations exhibiting a U-containing clay-rich layer within the top 30 cm. Additionally, in the porewater, the association of U(IV) with Fe(II) and organic matter colloids significantly increased U(IV) mobility in the wetland. In the present study, within the same wetland, we further demonstrate that the speciation of U at a location not impacted by the clay-rich layer is a different noncrystalline U(IV) species, consisting of U(IV) bound to organic matter in soil. We also show that the clay-poor location includes an abundant sulfate supply and active microbial sulfate reduction that induce substantial pyrite (FeS2) precipitation. As a result, Fe(II) concentrations in the porewater are much lower than those at clay-impacted zones. U porewater concentrations (0.02-0.26 µM) are also considerably lower than those at the clay-impacted locations (0.21-3.4 µM) resulting in minimal U mobility. In both cases, soil-associated U represents more than 99% of U in the wetland. We conclude that the low U mobility reported at clay-poor locations is due to the limited association of Fe(II) with organic matter colloids in porewater and/or higher stability of the noncrystalline U(IV) species in soil at those locations.

[Clinical study and electron microscope observation of tapeworm scolices on 548 cases of taeniasis treated with Binlang Chengqi Decoction].

OBJECTIVE: To observe the effect and mechanism of Chinese herbs in the treatment of taeniasis. METHODS: Five hundred and forty-eight cases of taeniasis were treated with Binlang Chengqi Decoction (BLCQD). The tapeworm scolices of ten cases were observed by electron microscope (EM). RESULTS: Among the 548 cases, 521 cases were cured and 27 cases were improved. The total effective rate was 100%. Foam-like secretion in the sucker of the tapeworm scolices and erosion of the epithelium in the cervical part were observed by scanning electron microscope. Observed by transmission electron microscope, the cortex was seriously damaged. The microvilli were exfoliated. The cells in the muscle layer and parenchyma layer were injured in various degrees. The mitochondria were tumefied or caved. And the nerve cord was damaged. CONCLUSION: BLCQD can not only paralyze the tapeworm scolex, but also injury the cells of the tapeworm scolex.