Coxsackievirus B3 HFMD animal models in Syrian hamster and rhesus monkey.

Coxsackievirus B3 (CVB3) is the pathogen causing hand, foot and mouth disease (HFMD), which manifests across a spectrum of clinical severity from mild to severe. However, CVB3-infected mouse models mainly demonstrate viral myocarditis and pancreatitis, failing to replicate human HFMD symptoms. Although several enteroviruses have been evaluated in Syrian hamsters and rhesus monkeys, there is no comprehensive data on CVB3. In this study, we have first tested the susceptibility of Syrian hamsters to CVB3 infection via different routes. The results showed that Syrian hamsters were successfully infected with CVB3 by intraperitoneal injection or nasal drip, leading to nasopharyngeal colonization, acute severe pathological injury, and typical HFMD symptoms. Notably, the nasal drip group exhibited a longer viral excretion cycle and more severe pathological damage. In the subsequent study, rhesus monkeys infected with CVB3 through nasal drips also presented signs of HFMD symptoms, viral excretion, serum antibody conversion, viral nucleic acids and antigens, and the specific organ damages, particularly in the heart. Surprisingly, there were no significant differences in myocardial enzyme levels, and the clinical symptoms resembled those often associated with common, mild infections. In summary, the study successfully developed severe Syrian hamsters and mild rhesus monkey models for CVB3-induced HFMD. These models could serve as a basis for understanding the disease pathogenesis, conducting pre-trial prevention and evaluation, and implementing post-exposure intervention.

Designing step-scheme AgI decorated Ta2O5-x heterojunctions for boosted photodegradation of organic pollutants.

Step-scheme (S-scheme) AgI decorated Ta2O5-x heterojunctions have been designed and synthesized via a combination of solvothermal and chemical deposition methods for enhanced visible-light harvesting and high-performance photocatalysis. The AgI nanoparticles showed great influences on the visible-light absorption and charge separation between AgI and Ta2O5-x microspheres. The experimental results indicated that the as-prepare AgI/Ta2O5-x composites achieved enhanced photocatalytic performance towards tetracycline degradation under visible light, and the AgI/Ta2O5-x-11 sample displayed the highest photocatalytic performance and the maximum rate constant of approximately 0.09483 min-1, which was 7.22 times that of Ta2O5-x microspheres and 2.56 times that of AgI, respectively. The highly enhanced photocatalytic performance was mainly attributed to the construction of S-scheme heterostructure and formation of oxygen vacancies in Ta2O5-x microspheres. In addition, the trapping experimental and DMPO spin-trapping ESR spectra confirmed the ⸱O2- and ⸱OH species as the main radicals during tetracycline degradation. Current work indicates an S-scheme tantalum-based composites for high-performance environmental photocatalysis.

Microbial community, pathogenic bacteria and high-risk anti-biotic resistance genes at two tropical coastal beaches adjacent to villages in Hainan, China.

OBJECTIVE: The aim of the study was to explore the correlation between characteristics of microbial community, pathogenic bacteria and high-risk antibiotic-resistant genes, between coastal beaches and a multi-warm-blooded host, as well as to determine potential species biomarkers for faecal source contamination on tropical coastal beaches in China. MATERIAL AND METHODS: The 'One-Health' approach was used in a microbiological study of beaches and warm-blooded hosts. The microbial.community was analyzed using 16S rRNA gene amplicons and shotgun metagenomics on Illumina NovaSeq. RESULTS: The Chao, Simpson, Shannon, and ACE indices of non-salt beach were greater than those of salt beaches at the genus and OTU levels (P < 0.001). Bacteroidota, Halanaerobiaeota, Cyanobacteria, and Firmicutes were abundant on salt beaches (P<0.01). Human-sourced microorganisms were more abundant on salt beaches, which accounted for 0.57%. Faecalibacterium prausnitzii and Eubacterium hallii were considered as reliable indicators for the contamination of human faeces. High-risk carbapenem-resistant Klebsiella pneumoniae and the genotypes KPC-14 and KPC-24 were observed on salt beaches. Tet(X3)/tet(X4) genes and four types of MCR genes co-occurred on beaches and humans; MCR9.1 accounted for the majority. Tet(X4) found among Cyanobacteria. Although rarely reported at Chinese beaches, pathogens, such as Vibrio vulnificus, Legionella pneumophila, and Helicobacter pylori, were observed. CONCLUSIONS: The low microbial community diversity, however, did not indicate a reduced risk. The transfer of high-risk ARGs to extreme coastal environments should be given sufficient attention.

A Compact Stacked RF Energy Harvester with Multi-Condition Adaptive Energy Management Circuits.

This paper presents a compact stacked RF energy harvester operating in the WiFi band with multi-condition adaptive energy management circuits (MCA-EMCs). The harvester is divided into antennas, impedance matching networks, rectifiers, and MCA-EMCs. The antenna is based on a polytetrafluoroethylene (PTFE) substrate using the microstrip antenna structure and a ring slot in the ground plane to reduce the antenna area by 13.7%. The rectifier, impedance matching network, and MCA-EMC are made on a single FR4 substrate. The rectifier has a maximum conversion efficiency of 33.8% at 5 dBm input. The MCA-EMC has two operating modes to adapt to multiple operating conditions, in which Mode 1 outputs 1.5 V and has a higher energy conversion efficiency of up to 93.56%, and Mode 2 supports a minimum starting input voltage of 0.33 V and multiple output voltages of 2.85-2.45 V and 1.5 V. The proposed RF energy harvester is integrated by multiple-layer stacking with a total size of 53 mm × 43.5 mm × 5.9 mm. The test results show that the proposed RF energy harvester can drive a wall clock (30 cm in diameter) at 10 cm distance and a hygrometer at 122 cm distance with a home router as the transmitting source.

A Compact RF Energy Harvesting Wireless Sensor Node with an Energy Intensity Adaptive Management Algorithm.

This paper presents a compact RF energy harvesting wireless sensor node with the antenna, rectifier, energy management circuits, and load integrated on a single printed circuit board and a total size of 53 mm × 59.77 mm × 4.5 mm. By etching rectangular slots in the radiation patch, the antenna area is reduced by 13.9%. The antenna is tested to have an S11 of -24.9 dB at 2.437 GHz and a maximum gain of 4.8 dBi. The rectifier has a maximum RF-to-DC conversion efficiency of 52.53% at 7 dBm input energy. The proposed WSN can achieve self-powered operation at a distance of 13.4 m from the transmitter source. To enhance the conversion efficiency under different input energy densities, this paper establishes an energy model for two operating modes and proposes an energy-intensity adaptive management algorithm. The experiments demonstrated that the proposed WSN can effectively distinguish between the two operating modes based on input energy intensity and realize efficient energy management.

Differences in the degradation behavior of disinfection by-products in UV/PDS and UV/H2O2 processes and the effect of their chemical properties.

In this work, sixteen typical chlorinated and brominated aromatic disinfection by-products (DBPs) were selected as examples to investigate their different degradation mechanisms initiated by HO• and SO4•-. Addition reactions were the main mode of degradation of DBPs by HO•, while SO4•- dominated H-abstraction reactions and single electron transfer reactions. Chlorinated compounds had higher reactivity than brominated compounds. Furthermore, substituents with stronger electron-donating effects promoted the electrophilic reaction of DBPs with the two radicals. In addition, we developed a model based on the chemical properties LUMO, fmax-, and hardness for predicting the average reaction energy barriers for the initial reactions of DBPs with HO• and SO4•-. The model had good predictive performance for the difficulty of degradation of different DPBs by HO• and SO4•-, with R2 values of 0.85 and 0.87, respectively. Through the degradation efficiency simulation, we found that longer reaction times, higher oxidant concentrations and lower pollutant concentrations were more favorable for the removal of DBPs. The UV/PDS process showed better degradation of DBPs than the UV/H2O2 process. In addition, most degradation products of DBPs exhibited less toxicity to aquatic organisms than their parent compounds. This study provided theoretical guidance for the degradation and removal of other aromatic DBPs at the molecular level.

Homogeneous and heterogeneous atmospheric ozonolysis of chlorobenzene:Mechanism, kinetics and ecotoxicity assessment.

The reactions between chlorobenzene(CB) and ozone have been studied comprehensively in this paper. Chlorobenzene is a commonly found chlorinated aromatic volatile organic compound(VOC), and its emission into the atmosphere can cause harm to the ecosystem and human health. The frequent occurrence of mineral particles from sandstorms exerts a significant influence on the atmospheric chemistry of the troposphere. Mineral particles are abundant in SiO2 and Al2O3 content. Therefore, we investigated the homogeneous and heterogeneous reaction processes of CB and ozone in the atmosphere by using density functional theory (DFT) method at the M06-2X/6-311++g(3df,2p)//M06-2X/6-31+g(d,p) level. The atmospheric fate, reaction rate and toxicity evaluation of CB ozonation were studied in the gas-phase section. Toxicity evaluation results showed that ozonation of CB could effectively reduce its toxicity. For the heterogeneous process, we simulated three types of SiO2 clusters and nine types of (Al2O3)n clusters, and studied the configurations of CB adsorbed on the cluster surfaces. We found that adsorption of CB on the SiO2 clusters was achieved through hydrogen bonding, while adsorption of CB on the Al2O3 clusters was achieved through both hydrogen bonding and metal bonding. The energy for CB adsorption on the (Al2O3)n cluster surface was higher than that for the SixOy(OH)z cluster surface, and both types of clusters exhibited efficient adsorption of CB. As the SixOy(OH)z clusters grew larger, the rates for the reactions between O3 and CB increased. CB travelled long distances along the Al2O3 clusters, leading to an extended influence range.

The regulatory mechanisms and inhibitors of isocitrate dehydrogenase 1 in cancer.

Reprogramming of energy metabolism is one of the basic characteristics of cancer and has been proved to be an important cancer treatment strategy. Isocitrate dehydrogenases (IDHs) are a class of key proteins in energy metabolism, including IDH1, IDH2, and IDH3, which are involved in the oxidative decarboxylation of isocitrate to yield α-ketoglutarate (α-KG). Mutants of IDH1 or IDH2 can produce d-2-hydroxyglutarate (D-2HG) with α-KG as the substrate, and then mediate the occurrence and development of cancer. At present, no IDH3 mutation has been reported. The results of pan-cancer research showed that IDH1 has a higher mutation frequency and involves more cancer types than IDH2, implying IDH1 as a promising anti-cancer target. Therefore, in this review, we summarized the regulatory mechanisms of IDH1 on cancer from four aspects: metabolic reprogramming, epigenetics, immune microenvironment, and phenotypic changes, which will provide guidance for the understanding of IDH1 and exploring leading-edge targeted treatment strategies. In addition, we also reviewed available IDH1 inhibitors so far. The detailed clinical trial results and diverse structures of preclinical candidates illustrated here will provide a deep insight into the research for the treatment of IDH1-related cancers.

Olmesartan alleviates SARS-CoV-2 envelope protein induced renal fibrosis by regulating HMGB1 release and autophagic degradation of TGF-ß1.

Background and aims: Renal damage in severe coronavirus disease 2019 (COVID-19) is highly associated with mortality. Finding relevant therapeutic candidates that can alleviate it is crucial. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin-receptor blockers (ARBs) have been shown to be harmless to COVID-19 patients, but it remains elusive whether ACEIs/ARBs have protective benefits to them. We wished to determine if ACEIs/ARBs had a protective effect on the renal damage associated with COVID-19, and to investigate the mechanism. Methods: We used the envelope (E) protein of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) to induce COVID-19-like multiple organ damage and observed renal fibrosis. We induced the epithelial-mesenchymal transformation of HK-2 cells with E protein, and found that olmesartan could alleviate it significantly. The protective effects of olmesartan on E protein-induced renal fibrosis were evaluated by renal-function assessment, pathologic alterations, inflammation, and the TGF-ß1/Smad2/3 signaling pathway. The distribution of high-mobility group box (HMGB)1 was examined after stimulation with E protein and olmesartan administration. Results: E protein stimulated HMGB1 release, which triggered the immune response and promoted activation of TGF-ß1/Smad2/3 signaling: both could lead to renal fibrosis. Olmesartan regulated the distribution of HMGB1 under E protein stimulation. Olmesartan inhibited the release of HMGB1, and reduced the inflammatory response and activation of TGF-ß1/Smad2/3 signaling. Olmesartan increased the cytoplasmic level of HMGB1 to promote the autophagic degradation of TGF-ß1, thereby alleviating fibrosis further. Conclusion: Olmesartan alleviates E protein-induced renal fibrosis by regulating the release of HMGB1 and its mediated autophagic degradation of TGF-ß1.

Plasmon-Mediated Photoelectrochemical Hot-Hole Oxidation Coupling Reactions of Adenine on Nanostructured Silver Electrodes.

Surface-enhanced Raman spectroscopy (SERS) has been widely applied in the identification and characterization of DNA structures with high efficiency. Especially, the SERS signals of the adenine group have exhibited high detection sensitivity in several biomolecular systems. However, there is still no unanimous conclusion regarding the interpretation of some special kinds of SERS signals of adenine and its derivatives on silver colloids and electrodes. This Letter presents a new photochemical azo coupling reaction for adenyl residues, in which the adenine is selectively oxidized to (E)-1,2-di(7H-purin-6-yl) diazene (azopurine) in the presence of silver ions, silver colloids, and electrodes of nanostructures under visible light irradiation. The product, azopurine, is first found to be responsible for the SERS signals. This photoelectrochemical oxidative coupling reaction of adenine and its derivatives is promoted by plasmon-mediated hot holes and is regulated by positive potentials and pH of solutions, which opens up new avenues for studying azo coupling in the photoelectrochemistry of adenine-containing biomolecules on electrode surfaces of plasmonic metal nanostructures.

Efficient removal of Cl-DBPs by direct-indirect continuous hydrodechlorination reduction reaction on Ti3C2X2 surface: A theoretical calculation.

Degradation of Chlorine-containing disinfection by-products(Cl-DBPs) on surface by electrocatalytic hydrodechlorination (EHDC) is considered a promising advanced water treatment method. Cl-DBPs have ecological toxicity and health risks so that it is urgent to degrade DBPs. We designed and verified the degradation performance of the EHDC of 18 kinds of DBPs (TAAs, TANs, TALs, TNMs, TAcAms, THMs) with different substituents led by the Ti3C2X2(X = O/OH) system by the first-principles. On the surface of Ti3C2(OH)2, DBPs react with atomic hydrogen (*H) by a direct-indirect continuous reduction mechanism to eliminate the Cl atom in turn. Dissociative adsorption of DBPs on the surface of Ti3C2(OH)2 simultaneously realizes the first electron transfer step and forms H vacancy, which makes its electrocatalytic activity superior to that of Ti3C2O2. Removing the six types of DBPs only needs to add -0.1 V of applied potential. In addition, we investigated the impact of substituents and chlorination degree on the reactivity of DBPs removal. The strong electron-withdrawing group is more conducive to the dechlorination reaction. Dehalogenation is much favorable in thermodynamics as the increase in chlorination degree. This study provides important insights and efficient catalysts for the degradation of DBPs and shows the potential of MXenes in eliminating chloride in water.

Relationship between BUN/Cr and Prognosis of HF Across the Full Spectrum of Ejection Fraction. / Relação entre a Razão Nitrogênio Ureico/Creatinina e Prognóstico de Insuficiência Cardíaca em Todo o Espectro da Fração de Ejeção.

BACKGROUND: In patients with heart failure (HF), due to the relative deficiency of blood volume, neurohormone system activation leads to renal vasoconstriction, which affects the content of blood urea nitrogen (BUN) and creatinine (Cr) in the body, while BUN and Cr are easily affected by other factors. Therefore, BUN/Cr can be used as another marker for the prognosis of HF. OBJECTIVE: Explore the prognosis of adverse outcome of HF in the high BUN/Cr group compared with the low BUN/Cr group across the full spectrum of ejection fraction. METHODS: From 2014 to 2016, symptomatic hospitalized HF patients were recruited and followed up to observe adverse cardiovascular outcomes. Logistic analysis and COX analysis were performed to determine significance. p-values <0.05 were considered statistically significant. RESULTS: In the univariate logistic regression analysis, the high BUN/Cr group had a higher risk of adverse outcome in heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF). Multivariate logistic regression analysis showed that the risk of cardiac death in the HFrEF group was higher than that in the low BUN/Cr group, while the risk of all-cause death was significant only in 3 months (p<0.05) (Central Illustration). The risk of all-cause death in the high BUN/Cr in the HFpEF group was significantly higher than that in the low BUN/Cr group at two years. CONCLUSION: The high BUN/Cr group is related to the risk of poor prognosis of HFpEF, and is not lower than the predictive value of left ventricular ejection fraction (LVEF).

FUNDAMENTO: Em pacientes com insuficiência cardíaca (IC), devido à relativa deficiência do volume sanguíneo, a ativação do sistema neuro-hormonal leva à vasoconstrição renal, que afeta o teor de nitrogênio ureico (NU) e creatinina (C) no organismo, sendo que NU e C são facilmente afetados por outros fatores. Portanto, a razão NU/C pode ser utilizada como mais um marcador para o prognóstico da IC. OBJETIVO: Explorar o prognóstico do desfecho adverso da IC no grupo NU/C alta em comparação com o grupo NU/C baixa em todo o espectro da fração de ejeção. MÉTODOS: De 2014 a 2016, pacientes sintomáticos hospitalizados com IC foram recrutados e acompanhados para observar desfechos cardiovasculares adversos. Foram realizadas análise logística e a análise COX para determinar a significância. Valores de p<0,05 foram considerados estatisticamente significativos. RESULTADOS: Na análise de regressão logística univariada, o grupo NU/C alta apresentou maior risco de desfecho adverso na insuficiência cardíaca com fração de ejeção reduzida (ICFEr) e insuficiência cardíaca com fração de ejeção preservada (ICFEp). A análise de regressão logística multivariada mostrou que o risco de morte cardíaca no grupo ICFEr foi maior do que no grupo NU/C baixa, enquanto o risco de morte por todas as causas foi significativo apenas em 3 meses (p<0,05) (Ilustração Central). O risco de morte por todas as causas no grupo NU/C alta no grupo ICFEP foi significativamente maior do que no grupo NU/C baixa em dois anos. CONCLUSÃO: O grupo NU/C alta está relacionado ao risco de mau prognóstico da ICFEP, não sendo inferior ao valor preditivo da fração de ejeção do ventrículo esquerdo (FEVE).

Hydroxylation of some emerging disinfection byproducts (DBPs) in water environment: Halogenation induced strong pH-dependency.

In this work, the hydroxylation mechanisms and kinetics of some emerging disinfection byproducts (DBPs) have been systematically investigated through theoretical calculation methods. Five chlorophenols and eleven halogenated pyridinols were chosen as the model compounds to study their pH-dependent reaction laws in UV/H2O2 system. For the reactions of HO• with 37 different dissociation forms, radical adduct formation (RAF) was the main reaction pathway, and the reactivity decreased with the increase of halogenation degree. The kapp values (at 298 K) increased with the increase of pH from 0 to 10, and decreased with the increase of pH from 10 to 14. Compared with phenol, the larger the chlorination degree in chlorophenols was, the stronger the pH sensitivity of the kapp values; compared with chlorophenols, the pH sensitivity in halogenated pyridinols was further enhanced. As the pH increased from 2 to 10.5, the degradation efficiency increased at first and then decreased. With the increase of halogenation degree, the degradation efficiency range increased, the pH sensitivity increased, the optimal degradation efficiency slightly increased, and the optimal degradation pH value decreased. The ecotoxicity and bioaccumulation of most hydroxylated products were lower than their parental compounds. These findings provided meaningful insights into the strong pH-dependent hydroxylation of emerging DBPs on molecular level.

The aomogeneous and heterogeneous oxidation of organophosphate esters (OPEs) in the atmosphere: Take diphenyl phosphate (DPhP) as an example.

Organophosphate esters (OPEs) are widely detected in the atmosphere. However, the atmospheric oxidative degradation mechanism of OPEs has not been closely examined. This work took density functional theory (DFT) to investigate the tropospheric ozonolysis of organophosphates, represented by diphenyl phosphate (DPhP), including adsorption mechanisms on the surface of titanium dioxide (TiO2) mineral aerosols and oxidation reaction of hydroxyl groups (·OH) after photolysis. Besides, the reaction mechanism, reaction kinetics, adsorption mechanism, and ecotoxicity evaluation of the transformation products were also studied. At 298 K, the total reaction rate constants kO3, kOH, kTiO2-O3, and kTiO2-OH are 5.72 × 10-15 cm3 molecule-1 s-1, 1.68 × 10-13 cm3 molecule-1 s-1, 1.91 × 10-23 cm3 molecule-1 s-1, and 2.30 × 10-10 cm3 molecule-1 s-1. The atmospheric lifetime of DPhP ozonolysis in the near-surface troposphere is 4 min, much lower than that of hydroxyl radicals (·OH). Besides, the lower the altitude is, the stronger the oxidation is. The TiO2 clusters carry DPhP promoting ·OH oxidation but inhibiting ozonolysis of DPhP. Finally, the main transformation products of this process are glyoxal, malealdehyde, aromatic aldehydes, etc., which are still ecotoxic. The findings shed new light on the atmospheric governance of OPEs.

Effect of different blood pressure levels on short-term outcomes in hospitalized heart failure patients.

Background: To investigate the influence of blood pressure (BP) level on short-term prognosis of heart failure (HF), the effect of the BP level on clinical end point events 3 months after discharge was observed. Methods: A retrospective cohort study was performed on 1492 hospitalized HF patients. All patients were divided according to systolic blood pressure (SBP) per 20 mmHg and diastolic blood pressure (DBP) per 10 mmHg. Logistic regression analysis was used to analyze the relationship between BP level and heart failure rehospitalization, cardiac death, all-cause death and a composite end point of heart failure rehospitalization/all-cause death at 3 month follow-up after discharge. Results: After multivariable adjustment, the relationship between SBP and DBP levels and outcomes followed an inverted J curve relationship. Compared with the reference group (110 < SBP≤130 mmHg), the risk of all end point events significantly increased in the SBP≤90 mmHg group included heart failure rehospitalization (OR 8.16, 95%CI 2.88-23.11, P < 0.001), cardiac death (OR 5.43, 95%CI 1.97-14.96, P = 0.001), all-cause death (OR 4.85, 95%CI 1.76-13.36, P = 0.002), and composite end point (OR 2.76, 95%CI 1.03-7.41, P = 0.044). SBP>150 mmHg significantly increased the risk of heart failure rehospitalization (OR 2.67, 95%CI 1.15-6.18, P = 0.022). Compared with.the reference group (65 < DBP≤75 mmHg), cardiac death (OR 2.64, 95%CI 1.15-6.05, P = 0.022) and all-cause death (OR 2.67, 95%CI 1.20-5.93, P = 0.016) was significantly increased in DBP≤55 mmHg group. There was no significant difference among subgroups according to left ventricular ejection fraction (P > 0.05). Conclusions: There is a significant difference in the short-term prognosis 3 months after discharge in HF patients with different BP levels at discharge. There was an inverted J curve relationship between BP levels and prognosis.

SARS-CoV-2 E protein: Pathogenesis and potential therapeutic development.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a devastating global pandemic, which has seriously affected human health worldwide. The discovery of therapeutic agents is extremely urgent, and the viral structural proteins are particularly important as potential drug targets. SARS-CoV-2 envelope (E) protein is one of the main structural proteins of the virus, which is involved in multiple processes of the virus life cycle and is directly related to pathogenesis process. In this review, we present the amino acid sequence of the E protein and compare it with other two human coronaviruses. We then explored the role of E protein in the viral life cycle and discussed the pathogenic mechanisms that E protein may be involved in. Next, we summarize the potential drugs against E protein discovered in the current studies. Finally, we described the possible effects of E protein mutation on virus and host. This established a knowledge system of E protein to date, aiming to provide theoretical insights for mitigating the current COVID-19 pandemic and potential future coronavirus outbreaks.

Repeated fluctuation of Cu2+ concentration during photocatalytic purification of SMZ-Cu2+ combined pollution: Behavior, mechanism and application.

Although the effect of Cu2+ on antibiotic removal during photocatalytic reaction has been studied in depth, there is less known about the effect of antibiotics on Cu2+ removal. In this study, we report for the first time that, during the photocatalytic purification of sulfamerazine (SMZ) and Cu2+ combined pollution, Cu2+ concentration showed an obvious five-stage fluctuation, which was completely different from the simple promotion or inhibition reported in previous studies. By employing HPLC-MS analysis and density functional theory (DFT) calculation, the repeated fluctuation of Cu2+ concentration was found to be closely related to the SMZ degradation process, mainly resulting from solution pH drop and formation of Cu-containing intermediates which acted as sacrificial agents for Cu2+ reduction. In addition, compared with the SMZ-free system, the presence of SMZ can greatly enhance the deep removal of Cu2+ (minimum Cu2+ concentration was only 0.17 mg/L vs. 1.28 mg/L without SMZ), and there was a wide time interval to ensure the efficient recovery of Cu metal. More interestingly, the in-situ obtained Cu-decorated TiO2 photocatalyst performed well in water splitting, nitrogen fixation and bacterial sterilization. Results of this study confirmed the great potential of photocatalytic technology in purifying antibiotic-heavy metal combined pollution.

Comparison of ribavirin degradation in the UV/H2O2 and UV/PDS systems: Reaction mechanism, operational parameter and toxicity evaluation.

Residues in surface water of ribavirin, which used extensively during the COVID-19 pandemic, have become an emerging issue due to its adverse impact on the environment and human health. UV/H2O2 and UV/peroxydisulfate (PDS) have different degradation effects on ribavirin, and the same operational parameter have different effects on the two processes. In this study, the reaction mechanism and degradation efficiency for ribavirin were studied to compare the differences under UV/H2O2 and UV/PDS processes. We calculated the total rate constants of ribavirin with HO• and SO4 •- in the liquid phase as 2.73 × 108 and 9.39 × 105 M-1s-1. The density functional theory (DFT) calculation results showed that HO• and SO4 •- react more readily with ribavirin via H-abstraction (HAA). The nitrogen-containing heterocyclic ring is difficult to undergo ring-opening degradation. The UV/PDS process was more stable and performed better than the UV/H2O2 for the ribavirin degradation when the same molar oxidant dosage was applied. HO• plays an extremely important role in the degradation of ribavirin by UV/PDS. The reason for this phenomenon is the combination of the higher yield of HO• produced in the UV/PDS process and the faster reaction rate of ribavirin with HO•. The UV/H2O2 process is more sensitive to pH than UV/PDS. Alkaline condition can significantly inhibit the ribavirin degradation. The effects of natural organic matter (NOM) and ribavirin concentration were also compared. Eventually, the toxicity prediction of the product showed that the opening-ring products were more toxic than the parent compound.

The multiple roles of phenols in the degradation of aniline contaminants by sulfate radicals: A combined study of DFT calculations and experiments.

Recent research revealed inhibition or enhancement of dissolved organic matter (DOM) to the degradation of trace organic contaminants (TrOC) in natural and engineered water systems. Phenols containing acetyl, carboxyl, formyl, hydroxy, and methoxy groups were selected as the model DOM to quantitatively study their roles in the degradation of simple anilines, sulfonamide antibiotics, phenylurea pesticides by sulfate radicals (SO4•-). Experimental results found that p-methoxyphenol inhibited aniline and sulfamethoxazole degradation by thermally activated peroxydisulfate (TAP), while p-acetylphenol slightly promoted aniline degradation. Quantum chemical calculations were applied to study the microscopic mechanism and kinetics of phenols affecting the degradation of aniline pollutants (AN) in three ways: competitively reacting with SO4•-, repairing aniline cationic radicals (AN•+) and phenylaminyl radicals (AN(-H)•), and generating phenoxy radicals to degrade anilines. Generally, the degradation of sulfonamides and phenylureas prefer to be inhibited by hydroxy- and methoxy-phenols with low oxidation potential (Eox), due to their diffusion-limiting reaction with SO4•- and rapid back-reduction AN•+ with the calculated rate constants of (0.02 - 6.38) × 109 M-1 s-1. Phenols repairing AN(-H)• through H abstraction reaction is speculated to possibly dominate the joint degradation of phenols and anilines by TAP, which has a poor correlation with Eox. This study provides mechanistic insight into the chemical behavior of complex and heterogeneous DOM in complex aqueous environments.

Ozone mechanism, kinetics, and toxicity studies of halophenols: Theoretical calculation combined with toxicity experiment.

Aromatic disinfection by-products (DBPs), which are generally more toxic than aliphatic DBPs, have attracted increasing attention. The toxicity of 13 typical halophenols on Scenedesmus obliquus was experimentally investigated, and the ozonation mechanism and kinetics of representative halophenols were further studied by quantum chemical calculations. The results showed that the EC50 values of halophenols ranged from 2.74 to 60.23 mg/L, and their toxicity ranked as follows: di-halogenated phenols > mono-halogenated phenols, mixed halogen-substituted phenols > single halogen-substituted phenols, and iodophenols > bromophenols > chlorophenols. The toxicity of halophenols was well described by the electronegativity index (ω) as lg(EC50)-1 = 6.228ω - 3.869, indicating halophenols capturing electrons as their potential toxicity mechanism. The reactions of O3 with halophenolate anions were dominated by three mechanisms: 1,3-dipolar cycloaddition, oxygen addition, and single electron transfer. The kinetic calculation indicated that O3 oxidized aqueous halophenols by reacting with halophenolate anions with the reaction rate constants as high as (0.91-3.47) × 1010 M-1 s-1. The number of halogen substituents affected the kO3, cal values of halophenolate anions, which are in the order of 2,4-dihalophenolate anions >4-halophenolate anions > 2,4,6-trihalophenolate anions. During the ozonation of 2,4,6-tribromophenol (246TBP), the toxic products (dimers and brominated benzoquinones) could be synergistically degraded by O3 and HO•. Thus, ozonation is feasible as a strategy to degrade aromatic DBPs.