Achieving high-efficient photocatalytic persulfate-activated degradation of tetracycline via carbon dots modified MIL-101(Fe)octahedrons

The synergistic reaction of photocatalysis and advanced oxidation is a valid strategy for the degradation of harmful antibiotic wastewater.Herein,carbon dots(CDs)modified MIL-101(Fe)octahedrons to form CDs/MIL-101(Fe)composite photocatalyst was synthesized for visible light-driven photocatalytic/persulfate(PS)-activated tetracycline(TC)degradation.The electron spin resonance(ESR)spectra,scavenging experiment and electrochemical analysis were carried out to reveal that the high visible light-driven photocatalytic degradation activity of TC over CDs/MIL-101(Fe)photocatalysts is not only ascribed to the production of free active radicals in the CDs/MIL-101(Fe)/PS system(·OH,·SO_(4-),^(1)O_(2),h^(+)and·O_(2)^(-))but also attributed to the consumption of electrons caused by the PS,which can suppress the recombination of photo-generated carriers as well as strong light scattering and electron trapping effects of CDs.Finally,the possible degradation pathways were proposed by analyzing intermediates via liquid chromatography-mass spectrometry technique.This research presents a rational design conception to construct a CDs/PS-based photocatalysis/advanced oxidation technology with high-efficient degradation activity for the remediation of organic antibiotic pollutant wastewater and for the improvement of carrier transport kinetics of photocatalysts.

Carbon-doped CuFe_(2)O_(4) with C-O-M channels for enhanced Fenton-like degradation of tetracycline hydrochloride: From construction to mechanism

Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.

Development of a Simple Extraction Method for Tetracycline Analogues from Bovine Milk

Tetracycline and analogues are among the most used antibiotics in the dairy industry. Besides the therapeutic uses, tetracyclines are often incorporated into livestock feed as growth promoters. A considerable amount of antibiotics is released unaltered through milk from dairy animals. The presence of antibiotic residues in milk and their subsequent consumption can lead to potential health impacts, including cancer, hypersensitivity reactions, and the development of antibiotic resistance. Thus, it is important to monitor residual levels of tetracyclines in milk. The purpose of this study is to develop a quick and simple method for simultaneously extracting five tetracycline analogues from bovine milk. Specifically, five tetracycline analogues: Chlortetracycline (CTC), demeclocycline (DEM), doxycycline (DC), minocycline (MC), and tetracycline (TC) were simultaneously extracted from milk using trifluoroacetic acid. Subsequently, the extracted analogues were separated by reverse-phase high-performance liquid chromatography (RP-HPLC) and detected at 355 nm using UV/Vis. Calibration curves for all five tetracycline analogues show excellent linearity (r2 value > 0.99). Percent recovery for MC, TC, DEM, CTC, and DC were: 31.88%, 96.91%, 151.29, 99.20%, and 85.58% respectively. The developed extraction method has good precision (RSD < 9.9% for 4 of the 5 analogues). The developed method with minimal sample preparation and pretreatment has the potential to serve as an initial screening test.

Efficacy and safety of low-dose tetracycline,amoxicillin quadruple therapy in Helicobacter pylori infection:A retrospective single center study

BACKGROUND Helicobacter pylori(H.pylori)eradication rates have declined with the rise of antibiotic-resistant strains in recent years.Although highly effective with a low prevalence of resistance,standard dose tetracycline is associated with frequent adverse events.The efficacy and safety of low-dose tetracycline as part of tetra-cycline and amoxicillin-containing bismuth quadruple therapy are not well described.AIM To compare the efficacy and safety of low-dose compared to standard dose tetracycline with combined amoxicillin-containing bismuth quadruple therapy in patients with H.pylori infection.METHODS Consecutive patients with H.pylori infection receiving tetracycline,amoxicillin,proton pump inhibitor,and bismuth for 14 days at Sir Run Run Shaw Hospital(1/2022-6/2023)were evaluated.The low-dose tetracycline group received tetracycline 500 mg twice daily(bid)while the standard dose group received 750 mg bid or 500 mg three times daily(tid).Primary endpoints were H.pylori eradication rate and treatment-related adverse events.

Mesoporous amorphous FeOOH-encapsulated BiO_(2–x) photocatalyst with harnessing broad spectrum toward activation of persulfate for tetracycline degradation

With the growing concern about the water environment,the advanced oxidation process of persulfate activation assisted by photocatalysis has attracted considerable attention to decompose dissolved organic micropollutants.In this work,to overcome the drawbacks of the photocatalytic activity reduction caused by the photo-corrosion of non-stoichiometric BiO_(2–x),a novel material with amorphous FeOOH in situ grown on layered BiO_(2–x) to form a core-shell structure similar to popcorn chicken-like morphology was produced in two simple and environmentally beneficial steps.Through a series of degradation activity tests of hybrid materials under different conditions,the as-prepared materials exhibited remarkable degradation activity and stability toward tetracycline in the FeOOH@BiO_(2–x)/Vis/PS system due to the synergism of photocatalysis and persulfate activation.The results of XRD,SEM,TEM,XPS,FTIR,and BET show that the loading of FeOOH increases the specific surface area and active sites appreciably;the heterogeneous structure formed by FeOOH and BiO_(2–x) is more favorable to the effective separation of photogenerated carriers.The optimal degradation conditions were at a catalyst addition of 0.7 g·L^(–1),a persulfate concentration of 1.0 g·L^(–1),and an initial pH of 4.5,at which the degradation rate could reach 94.7%after 90 min.The influence of typical inorganic anions on degradation was also examined.ESR studies and radical quenching experiments revealed that·OH,SO_(4)^(-)·,and·O_(2)^(-)were the principal active species generated during the degradation of tetracycline.The results of the 1,10-phenanthroline approach proved that the effect of dissolved iron ions on the tetracycline degradation was limited,and the interfacial reaction that occurs on the active sites on the material's surface was a critical factor.This work provides a novel method for producing efficient broad-spectrum Bismuth-based composite photocatalysts and photocatalytic-activated persulfate synergistic degradation of tetracycline.

Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

Preparation and characterization of ternary magnetic g-C_3N_4 composite photocatalysts for removal of tetracycline under visible light

A stable PNIPAM/Fe_3O_4/g-C_3N_4 composite photocatalyst was designed and prepared by a thermal photoinitiation technology.The structure and properties of the materials were characterized and the composite photocatalyst was found to show good stability for tetracycline degradation.The sample not only retained the magnetic properties of Fe_3O_4,allowing it to be recycled,but its photocatalytic properties could also be changed by controlling the temperature of the reaction system.The degradation intermediate products of tetracycline were further investigated by MS.This work provides a new facile strategy for the development of intelligent and recyclable photocatalytic materials.

Construction of a Tapetum-Specific and Tetracycline-Inducible System

A regulated gene expression system would offer the unique opportunity to study the gene physiological functions at different developmental stages. For realizing gene special expression in plant anther at given time, we constructed a new system that combined tetracycline- inducible elements with TA29 promoter, a tapetum-specific promoter of tobacco. The system was tested in transient GUS assay system by electroporation (gene gun) transformation of tobacco ( Nicotiana tabacum L. cv. Winsconsin 38) anther. In the absence of tetracycline as the inducer, no GUS activity was detected. However, strong GUS expression was observed in tapetum. tissue upon tetracycline induction, and little GUS activity was found outside the tapetum. Our results suggested that gene expression can be restricted to a specific tissue at the given time under the control of this new system, and this system would be a very useful tool for both basic plant biology research and biotechnological applications.

Electrochemically reduced graphene oxide with enhanced electrocatalytic activity toward tetracycline detection

An electrochemically reduced graphene oxide sample, ERGO_0.8v, was prepared by electrochemical reduction of graphene oxide （GO） at -0.8 V, which shows unique electrocatalytic activity toward tetracycline （TTC） detection compared to the ERGO-12v （GO applied to a negative potential of-1.2 V）, GO, chemically reduced GO （CRGO）-modified glassy carbon electrode （GC） and bare GC electrodes. The redox peaks of TTC on an ERGO-0.8v-modifled glass carbon electrode （GC/ERGO-0.8v） were within 0-0.5 V in a pH 3.0 buffer solution with the oxidation peak current correlating well with TTC concentration over a wide range from 0.1 to 160 mg/L Physical characterizations with Fourier transform infrared （FT-IR）, Raman, and X-ray photoelectron spectroscopies （XPS） demonstrated that the oxygen-containing functional groups on GO diminished after the electrochemical reduction at -0.8 V, yet still existed in large amounts, and the defect density changed as new sp2 domains were formed. These changes demonstrated that this adjustment in the number of oxygen-containing groups might be the main factor affecting the electrocatalytic behavior of ERGO. Additionally, the defect density and sp2 domains also exert a profound influence on this behavior. A possible mechanism for the TTC redox reaction at the GC/ERGO-0.8v electrode is also presented. This work suggests that the electrochemical reduction is an effective method to establish new catalytic activities of GO by setting appropriate parameters.

Meta-analysis:Is combination of tetracycline and amoxicillin suitable for Helicobacter pylori infection?

AIM:To access the efficacy of combination with amoxicillin and tetracycline for eradication of Helicobacter pylori(H.pylori),thus providing clinical practice guidelines.METHODS:Pub Med,EMBASE,Cochrane Central Register of Controlled Trials,Science Citation Index,China National Knowledge Infrastructure,Wanfang,and Chinese Biomedical Literature databases and abstract books of major European,American,and Asian gastroenterological meetings were searched.All clinical trials that examined the efficacy of H.pylori eradication therapies and included both tetracycline and amoxicillin in one study arm were selected for this systematic review and meta-analysis.Statistical analysis was performed with Comprehensive Meta-Analysis Software(Version 2).Subgroup,meta-regression,and sensitivity analyses were also carried out.RESULTS:Thirty-three studies met the inclusion criteria.The pooled odds ratio(OR)was 0.90(95%CI:0.42-1.78)for quadruple therapy with amoxicillin and tetracycline vs other quadruple regimens,and total eradication rates were 78.1%by intention-to-treat(ITT)and 84.5%by per-protocol(PP)analyses in the experimental groups.The pooled eradication rates of 14-d quadruple regimens with a combination of amoxicillin and tetracycline were 82.3%by ITT and89.0%by PP,and those of 10-d regimens were 84.6%by ITT and 93.7%by PP.The OR by ITT were 1.21(95%CI:0.64-2.28)for triple regimens with amoxicillin and tetracycline vs other regimens and 1.81(95%CI:1.37-2.41)for sequential treatment with amoxicillin and tetracycline vs other regimens,respectively.CONCLUSION:The effectiveness of regimens employing amoxicillin and tetracycline for H.pylori eradication may be not inferior to other regimens,but further study should be necessary.

Determination of fluoroquinolones, sulfonamides, and tetracyclines multiresidues simultaneously in porcine tissue by MSPD and HPLC-DAD

An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD) and high performance liquid chromatography (HPLC) with diode array detection (DAD) is developed to effectively determine two fiuoroquinolones (enoxacin and lomefioxacin), two sulfonamides (sulfanilamide and sulfamethoxazole) and one tetracycline (tetracycline) simultaneously in porcine tissues. In the process, MSPD methodology was used to treat samples, washed by n-hexane to remove lipid, eluted the analytes with acetonitrile–dichloromethane (1:1, v/v). Solvent acetonitrile and solvent acetic acid (0.1%) were combined in a gradient. HPLC–DAD analysis of the tissue samples was performed within 15 min at a fiow rate of 1.0 mL/min. The results showed that a recovery at 0.1, 0.5 and 1.0 mg/g fortification levels ranged from 80.6% to 99.2% with satisfactory relative standard deviations (RSDs) (below 6.1%, nfi3) and the limits of quantitation (LOQ) ranged from 7 mg/kg to 34 mg/kg in porcine tissues. Utilization of the method in successfully simultaneous analysis of porcine tissue incurred with veterinary drug multiresidues is described.

Detection and sequencing of plasmid encoded tetracycline resistance determinants(tetA and tetB) from food-borne Bacillus cereus isolates

Objective:To investigate the detection and sequencing of plasmid encoded tetracycline resistance genes(tet A and tet B) from food-borne and standard strains of Bacillus cereus(B. cereus).Methods:PCR was carried out to detect the tetracycline resistance genes(tet A and tet B) in food-borne B.cereus strains and the amplified products were sequenced.Results:The phenotypic resistance against tetracycline was observed in 39 of the 118 food-borne isolates and two reference strains(MTCC 430 and MTCC 1307) of B.cereus.Among the phenotypically resistant isolates,tet A was detected in 36 food-borne isolates and two reference strains(MTCC 430 and MTCC 1307).whereas,tel B was detected in 12 food-bome isolates and MTCC 1307 strain. Conclusions:A close association was therefore found between phenotypic resistance against tetracycline and presence of tetracycline resistance genes.The tet A and tet B gene fragments were amplified,purified and sequenced.The gene sequences of the isolates studied herein were found similar to tetA and tetB gene sequences of other bacteria available in NCBI.The occurrence of tetA and tetB genes in B.cereus indicate the horizontal transfer of antibiotic resistance determinants from other bacteria into B.cereus.The transfer of these resistant determinants to other potentially pathogenic bacteria may be a matter of great concern.

Determination of Tetracyclines and Their Epimers in Agricultural Soil Fertilized with Swine Manure by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry

A rapid, sensitive and specific ultra-high-performance liquid chromatography tandem mass spectrometry （UPLC-MS） method was developed for the analysis of tetracycline antibiotics, including tetracycline （TC）, oxytetracycline （OTC）, chlortetracycline （CTC） and their 4-epimers （4-epiTCs） in agricultural soil fertilized with swine manure. Soil samples were extracted and cleaned-up with 10 mL EDTA-McIlvaine buffer solution （pH 4.0）, then cleaned-up and pre-concentrated using the Oasis MAX cartridge and then eluted with 1 mL solution by mixing formic acid, methanol and water at a ratio of 2：15：83 （v/v/v）. The purified samples were separated by an ACQUITY UPLC BEH C18 column using acetonitrile and water containing 0.1% formic acid mobile phase and detected by a single quadrupole MS. The limits of detection for the soil extraction method （LODsoil） ranged from 0.6-2.5 lag kg-~ with recoveries from 23.3-159.2%. Finally, the method was applied to an agricultural field in an area with intensive pig-fattening farming. Tetracyclines were detected in soil from 2.8 to 42.4 μg kg-1 soil. These results demonstrate that soil from swine farms can become severely contaminated with tetracycline antibiotics and their metabolites.

Survey of Tetracyclines, Sulfonamides, Sulfamethazine, and Quinolones in UHT Milk in China Market

This study surveyed 180 samples of ultra high temperature （UHT） milk of four top Chinese dairy brands collected in the 25 cities in China in June 2011, and assessed their contamination with antibiotics, using the ELISA method. The percentages of tetracyclines, sulfonamides, sulfamethazine, and quinolones detected in the samples were 0, 16.7, 40.6, and 100%, respectively. The maximum concentrations of the tetracyclines, sulfonamides, sulfamethazine and quinolones in UHT milk samples were 〈1.5, 26.2, 22.6, and 58.8 μg kg-1, respectively. None of the samples exceeded the maximum residue levels （MRLs） for these four veterinary drugs, according to the regulations set by China, the European Union （EU） and the Codex Alimentarius Commission （CAC）.

Green Synthesis of Magnetic Adsorbent Using Groundwater Treatment Sludge for Tetracycline Adsorption

Groundwater treatment sludge is an industrial waste that is massively produced from groundwater treatment plants.Conventional methods for treatment of this sludge,such as discharge into deep wells or the sea,or disposal at landfills,are not environmentally sustainable.Here,we demonstrate an alternative strategy to recycle the sludge by preparing a magnetic maghemite adsorbent via a one-step hydrothermal method with NaOH solution as the only solvent.With this method,the weakly magnetized sludge,which contained 33.2%iron(Fe)and other impurities(e.g.,silicon(Si),aluminum(Al),and manganese(Mn)),was converted to magnetic adsorbent(MA)with the dissolution of Si/Al oxides(e.g.,quartz and albite)into the liquid fraction.At a NaOH concentration of 2 mol L^-1,approximately 18.1%of the ferrihydrite in the Fe oxides of the sludge was converted into 11.2%maghemite and 6.9%hematite after the hydrothermal treatment.MA2(i.e.,MA produced by a 2 mol L^-1 NaOH concentration)exhibited a good magnetic response of 8.2 emu g^-1(1 emu=10^-3 A m^2),and a desirable surface site concentration of 0.75 mmol g^-1.The synthesized MA2 was used to adsorb the cationic pollutant tetracycline(TC).The adsorption kinetics of TC onto MA2 fitted well with a pseudo-second-order model,and the adsorption isotherms complied well with the Langmuir model.The maximum adsorption capacity of MA2 for TC was 362.3 mg g^-1,and the main mechanism for TC adsorption was cationic exchange.This study is the first to demonstrate the preparation of an MA from recycled sludge without a reductant and/or exogenous Fe source.The prepared adsorbent can be used as a low-cost adsorbent with high capacity for TC sorption in the treatment of TC-containing wastewater.

Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization

High selective molecularly imprinted polymers （MIPs） for tetracycline have been prepared by precipitation polymerization. Effects of monomer and solvent, the ratio of monomer and template and the characterization of the polymer were investigated by frontal chromatography and selectivity experiment. The results clearly indicated that the polymer, which had the highest molecular recognition abilities for tetracycline antibiotics, had been received.

Preparation and Properties of CdS/Spherical g-C3N4 n-n Heterojunction as a Visible-Light-Driven Photocatalyst for Tetracycline Degradation

The CdS/spherical g-C3N4 n-n heterojunction photocatalyst was fabricated via a solvothermal method.The tetracycline was used to characterize the photocatalytic properties of the as-developed hybrids.The photocatalytic degradation mechanism of the as-developed heterojunction photocatalyst was also analyzed.Research results show that CdS nanoparticles are well dispersed in the surface layer of spherical g-C3N4.Moreover,the mass ratio of CdS to spherical g-C3N4 will influence the photocatalytic activity of the asdeveloped composites,which shows the trend of first increasing and then decreasing as it increased.When the mass ratio is 7:1,in 25 min,the as-developed heterojunction shows 93.2%of the maximum photocatalytic efficiency and still exhibits 83.6%after 5 times cycle testing.Moreover,the as-developed hybrids can accelerate the electron transport and improve the separation efficiency of photo-generated carriers compared with pure samples.In addition,the holes and superoxide radicals are dominating active species during the photocatalytic degradation process.

Electrochemical Aptasensor Based on Prussian Blue-Chitosan-Glutaraldehyde for the Sensitive Determination of Tetracycline

In this paper, a novel and sensitive electrochemical aptasensor for detecting tetracycline(TET)with prussian blue(PB) as the label-free signal was fabricated. A PB-chitosan-glutaraldehyde(PB-CS-GA)system acting as the signal indicator was developed to improve the sensitivity of the electrochemical aptasensor.Firstly, the PB-CS-GA was fixed onto the glass carbon electrode surface. Then, colloidal gold nanoparticles(Au NPs) were droped onto the electrode to immobilize the anti-TET aptamer for preparation of the aptasensor.The stepwise assembly process of the aptasensor was characterized by cyclic voltammetry(C-V) and scanning electron microscope(SEM). The target TET captured onto the electrode induced the current response of the electrode due to the non-conducting biomoleculars. Under the optimum operating conditions, the response of differential pulse voltammetry(DPV) was used for detecting the concentration of TET. The proposed aptasensor showed a high sensitivity and a wide linear range of 109-～ 105-M and 105-～ 102-M with the correlation coefficients of 0.994 and 0.992, respectively. The detection limit was 3.2×1010-M(RSD 4.12%). Due to its rapidity, sensitivity and low cost, the proposed aptasensor could be used as a pre-scanning method in TET determination for the analysis of livestock products.

Significant role of carbonate radicals in tetracycline hydrochloride degradation based on solar light-driven TiO2-seashell composites:Removal and transformation pathways

TiO2-seashell composites prepared via a sol-gel method were used to generate carbonate radicals(·CO3–) under solar light irradiation. ·CO3–, a selective radical, was employed to degrade the target tetracycline hydrochloride contaminant. A series of characterizations was carried out to study the structure and composition of the synthesized TiO2-seashell composite. This material exhibits excellent solar light-driven photochemical activity in the decomposition of tetracycline hydrochloride. The possible pathway and mechanism for the photodegradation process were proposed on the basis of high-resolution electrospray ionization time-of-flight mass spectrometry experiments. Finally, we investigated the reusability of the TiO2-seashell composite. This study is expected to provide a new facile pathway for the application of ·CO3– radicals to degrade special organic pollutants in water.

Application and Mechanism of ZnSb2O4 and ZnSb2O6 in the Photocatalytic Degradation of Tetracycline Hydrochloride

The photocatalytic performances in the photocatalytic degradation of tetracycline hydrochloride(TC) of ZnSb2O4 and ZnSb2O6 synthesized by hydrothermal method were explored.The effects of synthesis conditions including reaction temperature, reaction time, precursor solution pH, and the amount of hydrazine hydrate on the photocatalytic activity were discussed.The ZnSb2O4 and ZnSb2O6 photocatalysts prepared under optimal conditions exhibited similar photocatalytic activities for the degradation of TC. However, the areal photoctalytic activity of ZnSb2O4 was 12 times higher than that of ZnSb2O6 because of their different electronic and geometric structures. The photocatalytic degradation mechanisms of TC over ZnSb2O4 and ZnSb2O6 were proposed. Our work will facilitate the development of composite oxides consisting of p-block metal ions as new semiconductor photocatalysts.