Peroxydisulfate-Driven Reductive Dechlorination as Affected by Soil Constituents: Free Radical Formation and Conversion.

We report a previously unrecognized but efficient reductive degradation pathway in peroxydisulfate (PDS)-driven soil remediation. With supplements of naturally occurring low-molecular-weight organic acids (LMWOAs) in anaerobic biochar-activated PDS systems, degradation rates of 12 γ-hexachlorocyclohexanes (HCH)-spiked soils boosted from 40% without LMWOAs to a maximum of 99% with 1 mM malic acid. Structural analysis revealed that an increase in α-hydroxyl groups and a diminution in pKa1 values of LMWOAs facilitated the formation of reductive carboxyl anion radicals (COO•-) via electrophilic attack by SO4•-/•OH. Furthermore, degradation kinetics were strongly correlated with soil organic matter (SOM) contents than iron minerals. Combining a newly developed in situ fluorescence detector of reductive radicals with quenching experiments, we showed that for soils with high, medium, and low SOM contents, dominant reactive species switched from singlet oxygen/semiquinone radicals to SO4•-/•OH and then to COO•- (contribution increased from 30.8 to 66.7%), yielding superior HCH degradation. Validation experiments using SOM model compounds highlighted critical roles of redox-active moieties, such as phenolic - OH and quinones, in radical formation and conversion. Our study provides insights into environmental behaviors related to radical activation of persulfate in a broader soil horizon and inspiration for more advanced reduction technologies.

How to achieve adequate quenching for DBP analysis in drinking water?

Quenching is an important step to terminate disinfection during preparation of disinfected water samples for the analysis of disinfection byproducts (DBPs). However, an incomplete quenching might result in continued reactions of residual chlorine, whereas an excessive quenching might decompose target DBPs. Therefore, an adequate quenching to achieve simultaneous disinfection termination and DBP preservation is of particular importance. In this study, the two-stage reaction kinetics of chlorine and three commonly used quenching agents (i.e., ascorbic acid, sodium thiosulfate, and sodium sulfite) were determined. Stopping quenching during the first stage prevented interactions of residual chlorine with natural organic matter. Complete quenching was achieved by minimizing the quenching time for ascorbic acid and sodium sulfite, while limiting the quenching time to less than 3 min for sodium thiosulfate. At the optimized quenching times, the molar ratios (MRs) of quenching agent to chlorine were 1.05, 1.10, and 0.75 for ascorbic acid, sodium sulfite, and sodium thiosulfate, respectively. The destructive effects of the three quenching agents on total organic halogen (TOX) followed the rank order of ascorbic acid (33.7-64.8 %) < sodium sulfite (41.6-72.8 %) < sodium thiosulfate (43.3-73.2 %), and the destructive effects on aliphatic DBPs also followed the rank order of ascorbic acid (29.5-44.5 %) < sodium sulfite (34.9-51.9 %) < sodium thiosulfate (46.9-53.2 %). For total organic chlorine (TOCl) and aliphatic DBPs, the quenching behavior itself had more significant destructive effect than the quenching agent type/dose and quenching time, but for total organic bromine (TOBr), the destructive effect caused by quenching agent type/dose and quenching time was more significant. High-dose, long-duration quenching enhanced the reduction of TOX, but had little effect on aliphatic DBPs. Additionally, the three quenching agents reduced the levels of halophenols (except for tribromophenol), while maintained or increased the levels of tribromophenol, halobenzoic/salicylic acids, and halobenzaldehydes/salicylaldehydes. To achieve adequate quenching for overall DBP analysis in chlorinated water samples, it is recommended to use ascorbic acid at a quenching agent-to-chlorine MR of 1.0 for a quenching time of < 0.5 h.

Construction of surface-rich MoS2 nanoflowers decorated on 2D layered MXene nanohybrid heterostructure for highly efficient and rapid degradation of oxytetracycline.

In this study, we successfully developed a hybrid architecture referred to as MoS2@MX, involving the integration of MoS2 layered onto MXene using a straightforward co-precipitation method. This innovative hybrid photocatalyst exhibited remarkable efficiency in removing oxytetracycline (OTC) molecules from aqueous solutions under visible-light irradiation. During the photocatalytic process, both MoS2 and MX played distinct yet complementary roles. MoS2 facilitated efficient electron transfer, while MX contributed to the generation of radicals. This unique collaboration resulted in a noteworthy 99 % oxidation efficiency for OTC degradation within a brief 60 min of visible light exposure in an aqueous environment. The radicals 1O2 and •OH were identified as the principal drivers behind OTC degradation, underscoring the vital role of the hybrid material. Mechanistically, the degradation of OTC involved several key steps, including C-H bond cleavage, de-carboxylation, C-N bond oxidation, and de-chlorination. Importantly, the MoS2@MX hybrid composite demonstrated remarkable stability, maintaining a noteworthy photocatalytic efficiency of 89 % for targeted OTC removal after undergoing five consecutive cycles. In conclusion, this study emphasizes the potential of the MoS2@MX hybrid material as an effective agent for degrading organic OTC compounds within aquatic environments. The hybrid's multifaceted roles and exceptional performance suggest promising applications in sustainable water treatment.

Network Toxicology Prediction and Molecular Docking-based Strategy to Explore the Potential Toxicity Mechanism of Metformin Chlorination Byproducts in Drinking Water.

BACKGROUND: Metformin (MET), a worldwide used drug for treating type 2 diabetes but not metabolized by humans, has been found with the largest amount in the aquatic environment. Two MET chlorination byproducts, including Y and C, were transformed into drinking water during chlorination. However, the potential toxicity of the byproducts in hepatotoxicity and reproduction toxicity remains unclear. METHODS: The TOPKAT database predicted the toxicological properties of metformin disinfection by-products. The targets of metformin disinfection by-products were mainly obtained from the PharmMapper database, and then the targets of hepatotoxicity and reproductive toxicity were screened from GeneCards. The overlapping targets of toxic component targets and the hepatotoxicity or reproduction toxicity targets were regarded as the key targets. Then, the STRING database analyzed the key target to construct a protein-protein interaction network (PPI) and GO, and KEGG analysis was performed by the DAVID platform. Meanwhile, the PPI network and compound- target network were constructed by Cytoscape 3.9.1. Finally, Discovery Studio 2019 software was used for molecular docking verification of the two toxic compounds and the core genes. RESULTS: Y and C exhibited hepatotoxicity, carcinogenicity, and mutagenicity evaluated by TOPKAT. There were 22 potential targets relating to compound Y and hepatotoxicity and reproduction toxicity and 14 potential targets relating to compound C and hepatotoxicity and reproduction toxicity. PPI network analysis showed that SRC, MAPK14, F2, PTPN1, IL2, MMP3, HRAS, and RARA might be the key targets; the KEGG analysis indicated that compounds Y and C caused hepatotoxicity through Hepatitis B, Pathways in cancer, Chemical carcinogenesis-reactive oxygen species, Epstein-Barr virus infection; compound Y and C caused reproduction toxicity through GnRH signaling pathway, Endocrine resistance, Prostate cancer, Progesterone-mediated oocyte maturation. Molecular docking results showed that 2 compounds could fit in the binding pocket of the 7 hub genes. CONCLUSION: This study preliminarily revealed the potential toxicity and possible toxicity mechanism of metformin disinfection by-products and provided a new idea for follow-up research.

Unveiling the Halogenation-Induced Formation of Hg3Se2X2 (X = Cl, Br, and I) Compounds for Multiphase Mercury Cycling.

The interaction between mercury (Hg) and inorganic compounds, including selenium (Se), sulfur (S), and halogens (X = Cl, Br, or I), plays a critical role in the global mercury cycle. However, most previously reported mercury compounds are susceptible to reduction, leading to the release of elemental mercury (Hg0) and causing secondary pollution. In this study, we unveil a groundbreaking discovery that underscores the vital role of halogenation in creating exceptionally stable Hg3Se2X2 compounds. Through the dynamic interplay of Hg, Se, and halogens, an intermediary stage denoted [HgSe]m[HgX2]n emerges, and this transformative process significantly elevates the stabilization of mercury. Remarkably, halogen ions strategically occupy pores at the periphery of HgSe clusters, engendering a more densely packed atomic arrangement of Hg, Se, and halogen components. A marked enhancement in both thermal and acid stability is observed, wherein temperatures ascend from 130 to 300 °C (transitioning from HgSe to Hg3Se2Cl2). This sequence of escalating stability follows the order HgSe < Hg3Se2I2 < Hg3Se2Br2 < Hg3Se2Cl2 for thermal resilience, complemented by virtually absent acid leaching. This innovative compound formation fundamentally alters the transformation pathways of gaseous Hg0 and ionic mercury (Hg2+), resulting in highly efficient in situ removal of both Hg0 and Hg2+ ions. These findings pave the way for groundbreaking advancements in mercury stabilization and environmental remediation strategies, offering a comprehensive solution through the creation of chemically stable precipitates.

Efficacy and safety of iodized lecithin tablets versus spironolactone in alleviating central serous retinopathy among Chinese patients with uncontrolled diabetes.

To compare the effectiveness and safety of spironolactone versus lecithin-bound iodine in patients with central serous retinopathy (CSR). Chinese diabetes patients aged>18 years with CSR with persistent increased level of subretinal fluid (SRF) were enrolled. Subjects were randomized to receive either oral lecithin-bound iodine (390µg/kg/day) or oral spironolactone (50mg/day) for 6 months. A total of 200 patients were randomized and completed the study. Compared to spironolactone group, patients treated with lecithin-bound iodine had greater proportion of eye with complete resolution (87% vs 81%, p>0.005). Higher improvement in height of SRF was observed in lecithin-bound iodine-treated patients as compared with Spironolactone-treated patients (91.2[87.5] vs 142.5 [121.1]; p>0.005). However, no statistically significant difference was observed on none of comparisons. Compared to Spironolactone, the patients treated with lecithin-bound iodine had greater improvement in lesion size, central macular thickness and best-corrected visual acuity. However, no statistically significant difference was observed in any of parameter assessed. (p>0.005). The results of the present study suggested that the lecithin-bound iodine was found more effective (nnumerically) than spironolactone in Chinese diabetes patients with CSR.

A gold-complex initiated functionalization of biologically active polyphenols applied to a 18F-labeled chemical probe.

(-)-Epigallocatechin gallate (EGCG), a key component of green tea, exerts therapeutic anticancer and antiallergic properties through its binding to the 67 kDa laminin receptor. The functionalization of EGCG is a promising strategy for creating new drug candidates and chemical probes. In our study, we developed a method for effectively modifying the A ring of EGCG through an electrophilic aromatic substitution with amidomethyl 2-alkynylbenzoates initiated with a gold complex. The 2-alkynylbenzoates treated with (Ph3P)AuOTf under neutral conditions yielded N-acylimines. A further electrophilic aromatic substitution resulted in a mixture of EGCG substituted with acylaminomethyl groups at the 6 and 8 positions with a significant amount noted at the 6 position. We then explored the synthesis of 18F-labeled EGCG with a neopentyl labeling group, an effective labeling group for radiohalogens of not only fluorine-18 but also of astatine-211. To achieve this, we prepared precursors that possessed acid-sensitive protecting groups and base-unstable leaving groups using our established method. Substitution of EGCG with a neopentyl labeling group at either the C6 or C8 position did not affect its anticancer efficacy in U266 cells. Finally, we investigated the preparation of 18F-labeled EGCG. The 18F-fluorination of a mixture of 6- and 8-substituted precursors yielded the corresponding 18F-labeled compounds in 4.5% and 3.0% radiochemical yields (RCYs), respectively. Under acidic conditions, the 18F-labeled 8-substituted compound produced 18F-labeled EGCG in 37% RCY, which heralds the potential of our functionalization approach.

A multiway spectral analysis model to monitor the kinetic chlorination reaction of caffeine and determine its content in commercial liquid and solid drinks.

A multiway data analysis model, namely parallel factor analysis (PARAFAC) was proposed to decompose a three-way array of second-order kinetic UV measurements, for the chlorination reaction of caffeine with NaOCl, into a set of the spectra, time, and concentration matrices. The multiway resolution provided the simultaneous estimation of spectral, kinetic, and quantitative analysis of caffeine. The ability of the PARAFAC tool was checked by analyzing the validation samples in the presence of interferences. The added recovery and relative standard deviations for caffeine in the spiked samples were calculated as 99.1%-99.5% and 0.52%-1.34% for Iced Coffee Black liquid coffee (ICB), 99.5%-103.0% and 0.42%-1.03% for Jacobs Monarch Gold 100% Instant Coffee (JMG) and 99.5%-101.4% and 0.11%-0.13% for Çaykur Black Filter (Süzen) Bag Tea (BTB). Caffeine in commercial drinks was analyzed using the concentration matrices of the PARAFAC application. The PARAFAC results were statistically compared to those obtained by the developed UPLC method.

Effective removal of ammonia from aqueous solution through struvite synthesis and breakpoint chlorination: Insights into the synergistic effects of the hybrid system.

The ever-growing contamination of surface water due to various catchment activities poses threats and stress to downstream water treatment entities. Specifically, the presence of ammonia, microbial contaminants, organic matter, and heavy metals has been an issue of paramount concern to water treatment entities since stringent regulatory frameworks require these pollutants to be removed prior to water consumption. Herein, a hybrid approach that integrates struvite crystallization (precipitation) and breakpoint chlorination (stripping) for the removal of ammonia from aqueous solution was evaluated. To fulfil the goals of this study, batch experimental studies were pursued through the adoption of the well-known one-factor-at-a-time (AFAAT) method, specifically the effects of time, concentration/dosage, and mixing speed. The fate of chemical species was underpinned using the state-of-the-art analytical instruments and accredited standard methods. Cryptocrystalline magnesium oxide nanoparticles (MgO-NPs) were used as the magnesium source while the high-test hypochlorite (HTH) was used as the source of chlorine. From the experimental results, the optimum conditions were observed to be, i.e., Stage 1 - struvite synthesis, 110 mg/L of Mg and P dosage (concentration), 150 rpm of mixing speed, 60 min of contact time, and lastly, 120 min of sedimentation while optimum condition for the breakpoint chlorination (Stage 2) were 30 min of mixing and 8:1 Cl2:NH3 weight ratio. Specifically, in Stage 1, i.e., MgO-NPs, the pH increased from 6.7 to ≥9.6, while the turbidity was reduced from 9.1 to ≤1.3 NTU. Mn removal efficacy attained ≥97.70% (reduced from 174 µg/L to 4 µg/L) and Fe attained ≥96.64% (reduced from 11 mg/L to 0.37 mg/L). Elevated pH also led to the deactivation of bacteria. In Stage 2, i.e. breakpoint chlorination, the product water was further polished by eliminating residual ammonia and TPC at 8:1 Cl2-NH3 weight ratio. Interestingly, ammonia was reduced from 6.51 to 2.1 mg/L in Stage 1 (67.74% removal) and then from 2.1 to 0.002 mg/L post breakpoint chlorination (99.96% removal), i.e., stage 2. Overall, synergistic and complementary effects of integrating struvite synthesis and breakpoint chlorination hold great promise for the removal of ammonia from aqueous solutions thus confirming that this technology could potentially be used to curtail the effects of ammonia in the receiving environments and drinking water.

Fluorination Enhances NIR-II Emission and Photothermal Conversion Efficiency of Phototheranostic Agents for Imaging-Guided Cancer Therapy.

Phototheranostics with second near-infrared (NIR-II) imaging and photothermal effect have become a burgeoning biotechnology for tumor diagnosis and precise treatment. As important parameters of phototheranostic agents (PTAs), fluorescence quantum yield (QY) and photothermal conversion efficiency (PCE) are usually considered as a pair of contradictions that is difficult to be simultaneously enhanced. Herein, a fluorination strategy for designing A-D-A type PTAs with synchronously improved QY and PCE is proposed. Experimental results show that the molar extinction coefficient (ε), NIR-II QY, and PCE of all fluorinated PTAs nanoparticles (NPs) are definitely improved compared with the chlorinated counterparts. Theoretical calculation results demonstrate that fluorination can maximize the electrostatic potential difference by virtue of the high electronegativity of fluorine, which may increase intra/intermolecular D-A interactions, tighten molecule packing, and further promote the increase of ε, ultimately leading to simultaneously enhanced QY and PCE. In these PTA NPs, FY6-NPs display NIR-II emission extended to 1400 nm with the highest NIR-II QY (4.2%) and PCE (80%). These features make FY6-NPs perform well in high-resolution imaging of vasculature and NIR-II imaging-guided photothermal therapy (PTT) of tumors. This study develops a valuable guideline for constructing NIR-II organic PTAs with high performance.

Effects of the chlorination on organic matter removal and microbial communities during soil aquifer treatment for wastewater reclamation.

Soil aquifer treatment (SAT) has been widely applied for wastewater reclamation, which cooperates secondary treatment (i.e. A2O process) and disinfection treatment (chlorination) in wastewater treatment plants (WWTPs), to remove organic matter. This study compared dissolved organic carbon (DOC) characteristics, substrate utilisation patterns, and microbial communities between pre-chlorination SAT and SAT columns, and effective removals of DOC were observed in the pre-chlorination SAT and SAT columns. However, the composition of HiA in SAT columns without chlorination was less than in pre-chlorination SAT columns for DOC fraction. In comparison to A2O effluent, different metabolic patterns and the composition of the microbial community were demonstrated by the top layer of SAT column and pre-chlorination SAT column. Furthermore, deeper layers showed similarities in the metabolic pattern and composition of the microbial community. Overall, pre-chlorination minimised the change of the microbial communities from A2O effluent in the top layer of SAT except for deeper layers, and DOC concentrations decreased in pre-chlorination SAT column. Thus, the cooperation of SAT and wastewater treatments could be suitable for wastewater reclamation.

The Iodine Rush: Over- or Under-Iodination Risk in the Prophylactic Use of Iodine for Thyroid Blocking in the Event of a Nuclear Disaster.

Iodine is an essential element for the production of thyroid hormones (THs). Both deficient and excess iodine intakes may precipitate in adverse thyroidal events. Radioactive iodine (RI) is a common byproduct of nuclear fission processes. During nuclear emergencies RI may be released in a plume, or cloud, contaminating the environment. If inhaled or ingested, it may lead to internal radiation exposure and the uptake of RI mainly by the thyroid gland that absorbs stable iodine (SI) and RI in the same way. A dose of radiation delivered to the thyroid gland is a main risk factor for the thyroid cancer development. The SI prophylaxis helps prevent childhood thyroid cancer. The thyroid gland saturation with prophylactic SI ingestion, reduces the internal exposure of the thyroid by blocking the uptake of RI and inhibiting iodide organification. However, negative impact of inadequate SI intake must be considered. We provide an overview on the recommended iodine intake and the impact of SI and RI on thyroid in children and adolescents, discussing the benefits and adverse effects of the prophylactic SI for thyroid blocking during a nuclear accident. The use of SI for protection against RI may be recommended in cases of radiological or nuclear emergencies, moreover the administration of iodine for prophylactic purposes should be cautious. Benefits and risks should also be considered according to age. Adverse effects from iodine administration cannot be excluded. Precise indications are mandatory to use the iodine for thyroid blocking. Due to this natural adaption mechanism it's possible to tolerate large doses of iodine without clinical effects, however, a prolonged assumption of the iodine when not needed can be dangerous and may precipitate in severe thyroidal and non-thyroidal negative effects.

Treatment of synthetic dye containing textile raw wastewater effluent using UV/Chlorine/Br photolysis process followed by activated carbon adsorption.

This study investigated the efficiency and feasibility of ultraviolet (UV)-assisted photolysis of synthetic dye containing textile raw wastewater effluent. For a said purpose, in-house developed UV/Chlorine/Br process was followed in the presence of activated carbon (AC) which additionally facilitate the dye adsorption. In UV/Chlorine process Cl•, Cl2•-, and HO• are generated in the solution and destroyed compounds that cannot be oxidized by the conventional oxidant. In this process, free bromine is formed and photolyzed by UV radiation and generate Br• and Br2•- that can enhance the rate of pollutant degradation. In the present study, the dye removal efficiency was contributed by dark bromide (7.18%), UV irradiation (26.8%), dark chlorination (78.67%), and UV/Chlorine/Br (87.01%), respectively. With increasing pH from 3.0 to 8.30, the dye removal efficiency was enhanced but decreased by further increasing pH values. In addition, magnetized activated carbon from pomegranate husk using dual-stage chemical activation was used for post-adsorption of the residual dye and its degradation byproducts. The adsorption of the dye residues by AC followed the second-order kinetics with the rate constant of 1.7 × 10-3. The phytotoxicity of the treated textile wastewater by UV irradiation, dark chlorination, and UV/Chlorine/Br was assessed by seed germination of Lepidium sativum seeds. The highest inhibition effect on seed germination was related to treated wastewater by UV irradiation (more than 90% inhibition) that alleviated to less than 10% when this effluent diluted to 5% v/v. The highest germination was observed when the seeds were irrigated by the effluent of the UV/Chlorine/Br process. The significant reduction in the toxicity of the treated wastewater revealed that the UV/Chlorine/Br process has a considerable potential to effectively detoxify textile wastewater. Graphical abstract.

Are Disinfection Byproducts (DBPs) Formed in My Cup of Tea? Regulated, Priority, and Unknown DBPs.

Globally, tea is the second most consumed nonalcoholic beverage next to drinking water and is an important pathway of disinfection byproduct (DBP) exposure. When boiled tap water is used to brew tea, residual chlorine can produce DBPs by the reaction of chlorine with tea compounds. In this study, 60 regulated and priority DBPs were measured in Twinings green tea, Earl Grey tea, and Lipton tea that was brewed using tap water or simulated tap water (nanopure water with chlorine). In many cases, measured DBP levels in tea were lower than in the tap water itself due to volatilization and sorption onto tea leaves. DBPs formed by the reaction of residual chlorine with tea precursors contributed ∼12% of total DBPs in real tap water brewed tea, with the remaining 88% introduced by the tap water itself. Of that 12%, dichloroacetic acid, trichloroacetic acid, and chloroform were the only contributing DBPs. Total organic halogen in tea nearly doubled relative to tap water, with 96% of the halogenated DBPs unknown. Much of this unknown total organic halogen (TOX) may be high-molecular-weight haloaromatic compounds, formed by the reaction of chlorine with polyphenols present in tea leaves. The identification of 15 haloaromatic DBPs using gas chromatography-high-resolution mass spectrometry indicates that this may be the case. Further studies on the identity and formation of these aromatic DBPs should be conducted since haloaromatic DBPs can have significant toxicity.

Palm oil supply chain factors impacting chlorinated precursors of 3-MCPD esters.

Chlorinated compounds such as sphingolipid-based organochlorine compounds are precursors for the formation of 3-monochlororopanediol (3-MCPD) esters in palm oil. This study evaluates the effects of several factors within the palm oil supply chain on the levels of sphingolipid-based organochlorine, which in turn may influence the formation of 3-MCPD esters during refining. These factors include application of inorganic chlorinated fertiliser in the oil palm plantation, bruising and degradation of oil palm fruits after harvest, recycling of steriliser condensate as water for dilution of crude oil during oil palm milling, water washing of palm oil and different refining conditions. It was observed that bruised and degraded oil palm fruits showed higher content of sphingolipid-based organochlorine than control. In addition, recycling steriliser condensate during milling resulted in elevated content of sphingolipid-based organochlorine in palm oil. However, the content of sphingolipid-based organochlorine compounds was reduced by neutralisation, degumming and bleaching steps during refining. Although water washing of crude palm oils (CPO) prior to refining did not reduce the content of sphingolipid-based organochlorine, it did reduce the formation of 3-MCPD esters through the removal of water-soluble chlorinated compounds. It was found that the use of inorganic chlorinated fertiliser in plantations did not increase the content of chlorinated compounds in oil palm fruits and extracted oil, and hence chlorinated fertiliser does not seem to play a role in the formation of 3-MCPD esters in palm oil. Overall, this study concluded that lack of freshness and damage to the fruits during transport to mills, combined with water and oil recycling in mills are the major contributors of chlorinated precursor for 3-MCPD esters formation in palm oil.

Potassium permanganate as a promising pre-oxidant to treat low-viability cyanobacteria and associated removal of cyanotoxins and extracellular organic matters.

Cell-viability of cyanobacteria declines from development to decay stage during a successive bloom. Potassium permanganate (KMnO4) has demonstrated to be a superior pre-oxidant to treat high-viability cyanobacteria compared to other common oxidants (e.g., chlorine), but whether it is feasible to treat low-viability cyanobacteria is unknown. Here, effects of KMnO4 on membrane integrity, cyanotoxin fate and extracellular organic matters (EOMs) removal of high- and low-viability cyanobacteria were compared. Results showed that cell-viability of cyanobacteria could affect oxidant decay (kdecay), membrane damage (kloss), and cyanotoxins release (ki) and degradation (ke) during KMnO4 oxidation, similar to chlorination. However, unlike chlorination, initial low dosages of KMnO4 (0.5 and 1 mg L-1) minimized membrane damage for low-viability cyanobacteria (< 27%), and continuously decrease extracellular cyanotoxins, extracellular organic matters (EOMs), and aromatic compounds to some degrees (P<0.05). High dosages of KMnO4 (> 2 mg L-1) caused severe membrane destruction (> 89%) for low-viability cyanobacteria, leading to a fast increase of extracellular cyanotoxins within 1 h. However, total/extracellular cyanotoxins were oxidized to below the safety guideline of 1 µg L-1 after being dosed with sufficient oxidant exposure. EOMs and aromatic compounds were also reduced by 5-18% (P<0.05). Additionally, KMnO4-assisted coagulation significantly improved the removal of low-viability cyanobacteria (2-5 fold). Consequently, KMnO4 could be a promising pre-oxidant to treat low-viability cyanobacteria at decay stage of a successive bloom.

Anti-Inflammatory Comparison of Melatonin and Its Bromobenzoylamide Derivatives in Lipopolysaccharide (LPS)-Induced RAW 264.7 Cells and Croton Oil-Induced Mice Ear Edema.

The pineal gland is a neuroendocrine organ that plays an important role in anti-inflammation through the hormone melatonin. The anti-inflammatory effects of melatonin and its derivatives have been reported in both in vitro and in vivo models. Our previous study reported the potent antioxidant and neuroprotective activities of bromobenzoylamide substituted melatonin. In silico analysis successfully predicted that melatonin bromobenzoylamid derivatives were protected from metabolism by CYP2A1, which is a key enzyme of the melatonin metabolism process. Therefore, the anti-inflammatory activities of melatonin and its bromobenzoylamide derivatives BBM and EBM were investigated in LPS-induced RAW 264.7 macrophages and croton oil-induced ear edema in mice. The experiments showed that BBM and EBM significantly reduced production of the inflammatory mediators interleukin-6 (IL-6), prostaglandin E2 (PGE2), and nitric oxide (NO) in a dose-dependent manner, but only slightly affected TNF-α in LPS-induced RAW 264.7 macrophages. This suggests that modifying melatonin at either the N1-position or the N-acetyl side chain affected production of NO, PGE2 and IL-6 in in vitro model. In the croton oil-induced mouse ear edema model, BBM, significantly decreased ear edema thickness at 2-4 h. It leads to conclude that bromobenzoylamide derivatives of melatonin may be one of the potential candidates for a new type of anti-inflammatory agent.

Identification of chloramination disinfection by-products from phenylalanine in tap drinking water.

Phenylalanine (Phe) is widely present in natural water and serves as a precursor of disinfection by-products (DBPs). We reported the identification of chloramination DBPs from Phe in drinking water using ultra-high performance liquid chromatography (UHPLC) coupled with complementary high-resolution quadrupole time-of-flight (QTOF) and triple quadrupole (tQ) tandem mass spectrometry (MS/MS). In the chloraminated Phe water solution, sixteen new DBPs in a total of seventeen were identified based on their accurate mass, MS/MS spectra and 35Cl/37Cl isotopic patterns. Three of these DBPs were verified as benzamide, phenylacetamide, and p-hydroxyphenylacetamide with their standards, while the others were chlorinated derivatives of Phe, hydrazone, amidine, amide and peroxide, in which the unique structures of these DBPs were rarely reported. Their stability and formation process were investigated as well. Furthermore, a method consisting of solid phase extraction (SPE) and UHPLC-MS/MS using dynamic multiple reaction monitoring (dMRM) was developed to investigate these DBPs in authentic waters. Phe, benzamide, phenylacetamide, and N-Cl-2-phenylacetimidamide were detected in chlorinated tap water. Compared with the other identified DBPs, these three DBPs were exceptionally stable and could be formed in wide formation conditions. Our work not only provided ideas for the identification of new chloramination DBPs, but also demonstrated that some DBPs usually generated in the chloramination disinfection process could also be found in the chlorinated drinking water.

Application of the GC-HRMS based method for monitoring of short- and medium-chain chlorinated paraffins in vegetable oils and fish.

The aim of this study was to develop methods for the determination of short- and medium-chain chlorinated paraffins (SCCPs; MCCPs) in vegetable oils and fish employing gas chromatography coupled with high-resolution mass spectrometry because of a lack of information on the presence of chlorinated paraffins in food consumed in Europe. For isolation of CPs from fish, an ethyl acetate extraction followed by a clean-up of the extract by gel permeation chromatography was performed. The same purification step was used for the isolation of CPs from the vegetable oils. The concentration range for SCCPs was <10-389 ng/g lipid weight (lw, mean 36 ng/g lw for the oils and 28 ng/g lw for the fish) and that for MCCPs was <20-543 ng/g lw (mean 55 ng/g lw for the oils and 59 ng/g lw for the fish). There was found a high variability in concentrations of CPs influenced by area of origin.

Nitric Oxide Gas in Carbon Nanohorn/Fluorinated Dendrimer/Fluorinated Poly(ethylene glycol)-Based Hierarchical Nanocomposites as Therapeutic Nanocarriers.

Nitric oxide (NO) gas nanocarrier materials were prepared via a hierarchical assembly of poly(amido amine) dendrimers with fluorocarbon binding sites (DEN-F) and fluorinated poly(ethylene glycol) (F-PEG) on nitrogen-doped carbon nanohorns (NCNHs). The loading abilities of NO gas in these nanocarrier materials increased with the nitrogen doping of CNH and hierarchies formed by DEN-F and F-PEG. Especially, the ability of CNH-based nanocomposite materials was better than that of graphene-based materials. The loading of NO gas arose an infrared absorption band at 1387 cm-1 and increased the intensity ratio of D and G bands in Raman spectra, although these phenomena diminished after the degas treatment. The antimicrobial effects on bacteria (Escherichia coli and Staphylococcus aureus) increased depending on the loading amount of NO gas. It was confirmed from these results that NO gas weakly interacts with nitrogen-doped CNH and is trapped in the void volumes of DEN-F and F-PEG hierarchies. Thus, the concentric hierarchy is preferable for slow release of NO gas due to the void volumes in DEN-F, F-PEG, and CNH hierarchical organization. This sustained release of NO gas is advantageous with regards to the potential biomedical gas therapy against bacteria and other parasites.