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Well-dispersed MIL-100(Fe) nanoparticles were synthesized under mild conditions and used to construct a photo-Fenton system (VMH system) with the assistance of visible-light irradiation and hydrogen peroxide. In such a VMH system, the MIL-100(Fe) has a high specific surface area and provides numerous Fe3+ active sites, thus accelerating the reaction of Fe3+ with photo-generated electrons under visible-light irradiation and generates Fe2+, and then the acquired Fe2+ can activate H2O2 to generate ⋅OH, accompanying with the oxidation of Fe2+ to Fe3+. Hence, the in-situ recycling of Fe2+/Fe3+ promotes the generation of ·OH, thus making the VMH system exhibits promising photocatalytic activity. The removal rate of ciprofloxacin in the VMH system is as high as 95.2% within 120 min photo-Fenton reaction, which is about 26 times higher than that of the Visible light/MIL-100(Fe) system. Moreover, the VMH system also exhibits strong degradation ability to other typical antibiotics, such as tetracycline, norfloxacin and cephalexin, and maintains high cyclic stability, revealing great practical application potential in the purification of antibiotic wastewater. [ABSTRACT FROM AUTHOR]

In this research, graphene oxide (GO) as an adsorbent was used to remove norfloxacin and ceftriaxone antibiotics from aqueous solutions. All environmental factors affecting removal (e.g., pH, adsorbent mass, contact time, and concentration) were optimized in a discontinuous system. The design of experiments and the optimization of variables were carried out using the response surface method (RSM). The results of the analysis of variance (ANOVA) and the regression coefficients of the quadratic terms indicated that the responses were significantly affected by all the studied variables (P < 0.05). Also, the quadratic polynomial model results corresponded to empirical data with a high coefficient of determination (i.e., R² > 0.99 for both antibiotics). Besides, the adjusted R² (R²-adj >0.98 for both antibiotics) was close to R² values, indicating a good and acceptable statistical model. According to the results, the optimal removal of antibiotics by GO occurs in conditions of pH of 8, 0.034 g of the adsorbent mass, a sonication time of 20 min, and a concentration of 25 mg L-1. In these conditions, the maximum removal efficiencies of ceftriaxone and norfloxacin were equal to 95.87% and 98.64%, respectively. GO was recovered in five adsorption/desorption processes, and the removal efficiency declined very slightly after using the adsorbent for five cycles. Therefore, it is concluded that GO is an efficient and acceptable adsorbent for removing ceftriaxone and norfloxacin from aqueous environments. [ABSTRACT FROM AUTHOR]

Hydrochar from waste biomass is a promising material for removing emerging contaminants (e.g., antibiotics) in water/soil environment. Abundant small-sized hydrochar particles (HPs) with a high content of reactive functional groups and high mobility are easily released into ecosystems through hydrochar applications. However, the photodegradation ability and corresponding structures of HPs are largely unknown, which hinder accurate estimation of the remediation effect of hydrochar in ecosystems. Herein, photodegradation performance of HP towards targeted norfloxacin (NOR, a typical antibiotic) under light irradiation (visible and UV light) were investigated after adsorption processes upon release into soil/water, and its reactive species and photoactive structures were clarified and compared with those of residual bulk hydrochar (BH) comprehensively. The results showed that: (1) photodegradation percentages of HPs were 4.02 and 4.48 times higher than those of BHs under UV and visible light, in which reactive species of both HPs and BHs were ·OH and ·O2−; (2) density functional theory (DFT) results identified that the main photoactive structure of graphitic-N decreased the energy gap (Eg) of HPs, and C=O, COOH groups improved electron donating ability of BHs; (3) well-developed graphitization structure of HP resulted from higher polymerization reaction was an significant photoactive structure involving its superior photodegradation ability relative to that of BH. The distinct heterogeneities of photodegradation ability in HP and BH and underlying photoactive structures provide an in-depth understanding of hydrochar application for removing emerging contaminants in soil/water environment. Identifying photoactive structures is helpful to predict photodegradation ability of hydrochar according to their abundance. Highlights: Photodegradation percentage of HP from hydrochar application was ~4 times superior to that of BH in degradation of NOR. Major reactive species of HPs and BHs (·OH and ·O2−) were generated from graphitic-N and C=O/COOH groups, respectively. Photoactivity of HPs superior to BHs was mainly generated from well-developed graphitization structure of former. [ABSTRACT FROM AUTHOR]

Fe2O3/g-C3N4 nano-heterostructures for photocatalytic degradation of NOR (norfloxacin) were successfully prepared by combining co-precipitation and calcination methods. The g-C3N4, Fe2O3, and different composite ratios of Fe2O3/g-C3N4 (FeCNs) were characterized by XRD, SEM, XPS, UV-vis DRS, PL, and electrochemical tests, and the mechanism of photocatalytic degradation of NOR was analyzed. The results indicated that the semiconductor was attached to the surface of g-C3N4 in the form of α-Fe2O3 crystal with good crystalline structure. The composite of Fe2O3 with g-C3N4 increased the specific surface area of the material, effectively reduced the band gap, strengthened the photogenerated e−/h+ pair separation, and improved the photocatalytic performance of the composite. The photocatalytic degradation of NOR was consistent with the quasi-primary reaction kinetic model. Among them, FeCN-25wt% showed the optimal photocatalytic degradation of NOR (72.3%) with the largest degradation rate (k = 0.00900 min−1). The Fe2O3/g-C3N4 composite structure is inferred to be a Z-type heterojunction. [ABSTRACT FROM AUTHOR]

In this paper, BiVO4/CeVO4 composites were synthesized by hydrothermal method for photodegradation of norfloxacin (NFX) under visible light irradiation. The structure, morphologies, and optical properties of as-prepared samples were studied with XRD, SEM, BET, DRS, PL, XPS, EIS, and TPR. The results of the photocatalytic experiments demonstrated that the BiVO4/CeVO4 composites had more degradation performance of NFX compared with pure BiVO4 or CeVO4, which was attributed to the increased absorbance intensity of visible light, the reduced carrier coincidence rate, and the improved charge separation efficiency. Furthermore, the possible mechanism of the NFX degradation on BiVO4/CeVO4 composites under visible light irradiation was proposed according to the photocatalytic activity and free radicals trapping experiments. [ABSTRACT FROM AUTHOR]

Norfloxacin (NOX), a broad spectrum fluoroquinolone (FQ) antibiotic, is commonly detected in environmental residues, potentially contributing to biological drug resistance. In this paper, an aptamer recognition probe has been used to develop a label-free liquid crystal-based biosensor for simple and robust optical detection of NOX in aqueous solutions. Stimuli-receptive liquid crystals (LCs) have been employed to report aptamer–target binding events at the LC–aqueous interface. The homeotropic alignment of LCs at the aqueous–LC interface is due to the self-assembly of the cationic surfactant cetyltrimethylammonium bromide (CTAB). In the presence of the negatively charged NOX aptamer, the ordering changes to planar/tilted. On addition of NOX, the aptamer–NOX binding causes redistribution of CTAB at the LC–aqueous interface and the homeotropic orientation is restored. This results in a bright-to-dark optical transition under a polarized optical microscope (POM). This optical transition serves as a visual indicator to mark the presence of NOX. The devised aptasensor demonstrates high specificity with a minimum detection limit of 5 nM (1.596 ppb). Moreover, the application of the developed aptasensor for the detection of NOX in freshwater and soil samples underscores its practical utility in environmental monitoring. This proposed LC-based method offers several advantages over conventional detection techniques for a rapid, feasible and convenient way to detect norfloxacin. [ABSTRACT FROM AUTHOR]

In this study, magnetic coconut shell biochar loaded with spherical Fe3O4 and γ-Fe2O3 particles was successfully synthesized using a chemical coprecipitation method. The magnetic biochar exhibited a good magnetic separability and environmental security. The maximum sulfadiazine (SDZ) and norfloxacin (NOR) removal efficiencies were 94.8% and 92.3% at pH 4 and 25 °C with adsorbent dosage of 2.5 g/L, respectively. When antibiotic concentrations ranged from 5 to 50 mg/L, the theoretical maximum adsorption capacities of SDZ and NOR were 16.7 mg/g and 25.8 mg/g, respectively. The Langmuir isotherm and pseudo-second-order kinetic models could better describe the adsorption process of both antibiotics, implying the monolayer chemical adsorption. The thermodynamic analysis indicated that the adsorption process was spontaneous and endothermic. The ionic strength had no significant effect on the adsorption behavior of either antibiotic. Combined with BET, FTIR, and XPS results, the dominant mechanisms for SDZ and NOR adsorption were pore filling, π-π electron-donor–acceptor interaction, hydrogen bonds and surface complexation. Moreover, Lewis acid–base interaction also contributed to SDZ adsorption. [ABSTRACT FROM AUTHOR]

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The detection of quinolone antibiotics is an important research hotspot for protecting human health. Herein, a three‐dimensional metal–organic framework with the formula of {[Co5(TPT)2(BPDC)3(μ3‐O)2(H2O)4]·8MeCN·3DMF}n (NS‐3, TPT = tris(4‐pyridyl)‐1,3,5‐triazin, H2BPDC = 1,4‐benzenedicarboxylic acid) has been successfully prepared through solvothermal method. Single‐crystal X‐ray diffraction analysis revealed that three‐dimensional NS‐3 can be viewed as an eight‐connected sqc4 net with pentanuclear [Co5(μ3‐O)2]6+ cluster as metal nodes. Importantly, when norfloxacin, ofloxacin, and enrofloxacin were added in NS‐3 ethanol suspension, the luminescence intensity of NS‐3 at 333 nm was obviously decreased while new emission peaks clearly emerged, indicating that NS‐3 can be a potential rare fluorescent detection to recognize quinolone antibiotics in ethanol. Additionally, NS‐3 exhibits high sensitivity to norfloxacin, ofloxacin, and enrofloxacin with a limit of detection of 43, 34, and 139 nM, respectively, which is superior to most of the reported metal–organic frameworks. [ABSTRACT FROM AUTHOR]

The direct equalizing ray method was employed to design three groups of mixtures of oxytetracycline(OTC) and norfloxacin(NOR) with varying proportions(Group R1 had a higher proportion of OTC, while R2 had similar concentrations of both antibiotics, and R3 had a higher proportion of NOR).The effects of these mixtures on the content and properties of extracellular polymeric substances (EPS) in the biological denitrification process were investigated using an sequencing batch reactor activated sludge reactor (SBR). The results revealed that the removal rates of ammonia nitrogen(NH 3 -N) decreased in all three groups with the addition of antibiotics. As the antibiotic concentration increased, the EPS content decreased by 68.46%, 55.53%, and 65.03% in R1, R2, and R3, respectively. To understand the interaction mechanism of mixed antibiotics on EPS in activated sludge, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) techniques were employed. The findings demonstrated significant effects of mixed antibiotics on functional groups such as C-O, C O, and C-O-C. Specifically, hydrogen bonding was found to be the primary influencing factor in the R1 ratio, while Π-Π conjugation played a major role in the R3 ratio. [Display omitted] • High-concentration mixture of OTC and NOR inhibitory nitrogen removal performance of SBR. • High-concentration mixture of OTC and NOR reduced the production of extracellular polymeric substances. • High proportion of OTC, the EPS characteristics are mainly affected by hydrogen bonding interactions. • High proportion of NOR, the EPS characteristics are mainly affected by hydrogen bonding interactions and π-π conjugation. [ABSTRACT FROM AUTHOR]

[Display omitted] • N -doped C-coated Cu0/NC3-600 catalyst was prepared by pyrolysis of modified Cu-MOF. • Cu0/NC3-600 can fulfill effective degradation of NOR in the range of pH 3–11. • At pH 9, the removal of 20 mg/L NOR by 1 g/L Cu0/NC3-600 reached 98.34 % after 60 min. • In Cu0/NC3-600/air system, •O 2 – is the main active specie in acidic conditions. • Cu3+ and •O 2 – act together under alkaline conditions to destroy NOR. The Fenton-like activated molecular oxygen technology demonstrates significant potential in the treatment of refractory organic pollutants in wastewater, offering promising development prospects. We prepared a N -doped C -coated copper-based catalyst Cu0/NC3-600 through the pyrolysis of Mel-modified Cu-based metal–organic framework (MOF). The results indicate that the degradation of 20 mg/L norfloxacin (NOR) was achieved using 1.0 g/L Cu0/NC3-600 across a wide pH range, with a removal rate exceeding 95 % and total organic carbon (TOC) removals approaching 70 % after 60 min at pH 5–11. The nitrogen doping enhances the electronic structure of the carbon material, facilitating the adsorption of molecular oxygen. Additionally, the formed carbon layer effectively prevent copper leaching,contributing to increased stability to a certain extent. Subsequently, we propose the catalytic reaction mechanism for the Cu0/NC/air system. Under acidic conditions, Cu0/NC3-600 activates molecular oxygen to produce the •O 2 –, which serves as the primary active species for NOR degradation. While in alkaline conditions, the high-valent copper species Cu3+ is generated in conjunction with •O 2 –, both working simultaneously for NOR degradation. Furthermore, based on the LC-MS results, we deduced four possible degradation pathways. This work offers a novel perspective on expanding the pH range of copper-based catalysts with excellent ability to activate molecular oxygen for environmental water treatment. [ABSTRACT FROM AUTHOR]

Using red mud from alumina industry waste and edible fungus industry waste fungus rod as raw materials, red mud/waste fungus magnetic biochar (RMMBC) was prepared by co-pyrolysis method, and its morphological characteristics, pore structure and surface functional group changes were analyzed, its adsorption effect on norfloxacin(NOR) in water was explored, and its adsorption mechanism was explored by adsorption kinetics and isothermal adsorption characteristics, and tested in actual wastewater. The results showed that the optimal preparation conditions were raw material ratio (red mud, waste bacterial residue, urea) 1: 2.5: 0.5, calcination time 1 h, calcination temperature 700 °C. The maximum removal rate of NOR was 96.3% when a NOR concentration was 10 mg/L and 0.25 g RMMBC was added. The results showed that RMMBC had a large specific surface area(59.295 m²/g), pore volume (20.157 cm³/g) and saturation magnetic susceptibility(16.735 emu/g). The quasi-secondary kinetics of RMMBC and the Fre- undlich isothermal model can accurately describe the adsorption process of NOR on RMMBC, indicating that chemisorption may be the main mechanism of NOR adsorption on RMMBC, mainly including IT-IT interaction, surface complexation, hydrophobicity, hydrogen bonding and electrostatic interaction. The use of red mud and waste bacterial residue to prepare magnetic biochar adsorption effect is remarkable, which has the advantage of easy separation from the water body to avoid secondary pollution to the environment, which not only provides new ideas for low-cost treatment of antibiotic wastewater, but also helps to realize the stability, harmlessness and resource utilization of red mud and waste bacterial residue, and achieves the environmental protection goal of "waste treatment". [ABSTRACT FROM AUTHOR]

Composting emerges as an effective strategy to eliminate antibiotics and antibiotic resistance genes (ARGs) in animal manure. In this study, chicken manure with the addition of wheat straw and sawdust was used as composting raw materials, and different concentrations of norfloxacin were added to investigate its effects on physicochemical properties, bacterial community, and ARGs during the composting process. Results show that the presence of norfloxacin has obvious effects on the composting physicochemical properties and germination index (GI). A high concentration of norfloxacin influences the succession direction of the bacterial community and promotes the transfers of gyrA, gyrB, parC, qepA, and qnrB. The composting physicochemical properties alter bacterial communities and further influence the fate of ARGs. These results suggest that meticulous management of antibiotic usage and compost conditions are vital strategies for mitigating the influx of antibiotics and ARGs into the environment, both at the source and on the path. [ABSTRACT FROM AUTHOR]

• Doxycycline was more toxic, than norfloxacin on tested aquatic organisms: plants and crustaceans. • The effect concentration (EC 20) of doxycycline reduced by 20 % growth of L. minor was more than twice lower than for norfloxacin. • The leaf chlorophyll content was an early and sensitive indicator of the phytoxic effects of doxycycline in L. minor , before morphological changes were observed. • The effect concentration (EC 20 in 180. min) of doxycycline immobilizing of daphnia by 20 % was almost twice lower as for norfloxacin. The main reason for the appearance of pharmaceutical compounds in the aquatic environment is their regular excretion by humans and animals in an unchanged form or slightly metabolized. Pharmaceuticals limit the habitable living environment for aquatic organisms, because they can be toxic not only to bacteria but also to non-target organisms. Plants of the Lemnoideae subfamily and crustaceans Daphniindae family are widely used as bioindicators in freshwater environmental risk assessments. This study aimed to use biotests (Lemna test and Daphtoxkit) to determine the effect of two pharmaceuticals: antibiotic – Doxycycline (DOX) and semi-synthetic chemotherapeutic drug – Norfloxacin (NOR) on plants Lemna minor and crustaceans Daphnia magna. Standard Lemna test was extended to include pharmaceutical effects on plant chlorophyll content (LCC) and fluorescence (Fo, Fm, and Fv/Fm), and the confirmation of drug toxicity was the biotest Daphtoxkit assessing the immobilization (IM) of organisms. Studies have shown that DOX was more toxic than NOR on tested aquatic organisms: plants and crustaceans. The lowest observed effect concentration (EC 20) of DOX and NOR reduced by 20 % LCC and Iy of L. minor was 2.14 and 8.11 mg × L −1, respectively. The LCC was an early and sensitive indicator of the phytotoxic effects of DOX in L. minor before morphological changes were observed. Confirmation of drug toxicity was the Daphtoxkit. The EC 20 (180. min) of DOX and NOR, IM of daphnia by 20 % was 117.18 and 215.42 mg × L −1, respectively. In conclusion, DOX and NOR in aquatic environments may have significant implications for tested organisms and their ecosystems. [ABSTRACT FROM AUTHOR]

The application of hydrochar as a cost-effective solution has received much attention for the remediation of contaminated water. An economical and environmental approach to enhancing the physicochemical and adsorption performance of hydrochar is essential. In this study, the green technology of ball-milling was firstly employed to improve the adsorption capacity of hydrochar for the typical antibiotics norfloxacin. Aqueous batch adsorption experiment using both pristine and ball milled hydrochar derived from water hyacinth, prepared by hydrothermal carbonization at three temperatures (180, 200, 220 °C) was conducted. The results showed that ball-milling decreased the specific surface area of hydrochar, but still greatly enhanced their performance on the adsorption of norfloxacin. Surface functional groups, aromatization degree, and hydrophobicity of hydrochar were increased after ball-milling, as evidenced by measurements of Boehm titration, Raman spectra, and contact angle, respectively. With these changes, all the ball-milled water hyacinth hydrochar exhibited a better performance on the adsorption of norfloxacin than pristine hydrochar. Ball-milled 220 °C water hyacinth hydrochar showed the greatest norfloxacin adsorption (68.53 mg g−1) compared to unmilled hydrochar (24.29 mg g−1), and the enhancement was effective in a wide pH range (5–9) in aqueous solutions. The thermodynamics study indicated that the norfloxacin adsorption on ball-milled hydrochar was both physically spontaneous and exothermic. Combined physicochemical characterization of hydrochar and batch experiment results suggest that the enhanced adsorption capacity was owing to boosting H-bonds, π-π electron-donor–acceptor, and hydrophobic interaction. This study suggested that ball-milling can be served as a facile, green, and cost-effective method to obtain modified hydrochar for the removal of pollutants in water. Highlights: • Surface functional groups and hydrophobicity of hydrochar were increased after ball-milling. • Ball-milling was firstly used to modify hydrochar (BMHC) to remove antibiotics. • BMHC had a high adsorption capacity of 68.53 mg g-1 for norfloxacin (NOR). • NOR adsorption on BMHC was enhanced by increased H-bonds, π-π EDA, and hydrophobic interaction. [ABSTRACT FROM AUTHOR]

Abstract Hydrochar from waste biomass is a promising material for removing emerging contaminants (e.g., antibiotics) in water/soil environment. Abundant small-sized hydrochar particles (HPs) with a high content of reactive functional groups and high mobility are easily released into ecosystems through hydrochar applications. However, the photodegradation ability and corresponding structures of HPs are largely unknown, which hinder accurate estimation of the remediation effect of hydrochar in ecosystems. Herein, photodegradation performance of HP towards targeted norfloxacin (NOR, a typical antibiotic) under light irradiation (visible and UV light) were investigated after adsorption processes upon release into soil/water, and its reactive species and photoactive structures were clarified and compared with those of residual bulk hydrochar (BH) comprehensively. The results showed that: (1) photodegradation percentages of HPs were 4.02 and 4.48 times higher than those of BHs under UV and visible light, in which reactive species of both HPs and BHs were ·OH and ·O2 −; (2) density functional theory (DFT) results identified that the main photoactive structure of graphitic-N decreased the energy gap (Eg) of HPs, and C=O, COOH groups improved electron donating ability of BHs; (3) well-developed graphitization structure of HP resulted from higher polymerization reaction was an significant photoactive structure involving its superior photodegradation ability relative to that of BH. The distinct heterogeneities of photodegradation ability in HP and BH and underlying photoactive structures provide an in-depth understanding of hydrochar application for removing emerging contaminants in soil/water environment. Identifying photoactive structures is helpful to predict photodegradation ability of hydrochar according to their abundance. Graphical Abstract

Abstract The application of hydrochar as a cost-effective solution has received much attention for the remediation of contaminated water. An economical and environmental approach to enhancing the physicochemical and adsorption performance of hydrochar is essential. In this study, the green technology of ball-milling was firstly employed to improve the adsorption capacity of hydrochar for the typical antibiotics norfloxacin. Aqueous batch adsorption experiment using both pristine and ball milled hydrochar derived from water hyacinth, prepared by hydrothermal carbonization at three temperatures (180, 200, 220 °C) was conducted. The results showed that ball-milling decreased the specific surface area of hydrochar, but still greatly enhanced their performance on the adsorption of norfloxacin. Surface functional groups, aromatization degree, and hydrophobicity of hydrochar were increased after ball-milling, as evidenced by measurements of Boehm titration, Raman spectra, and contact angle, respectively. With these changes, all the ball-milled water hyacinth hydrochar exhibited a better performance on the adsorption of norfloxacin than pristine hydrochar. Ball-milled 220 °C water hyacinth hydrochar showed the greatest norfloxacin adsorption (68.53 mg g−1) compared to unmilled hydrochar (24.29 mg g−1), and the enhancement was effective in a wide pH range (5–9) in aqueous solutions. The thermodynamics study indicated that the norfloxacin adsorption on ball-milled hydrochar was both physically spontaneous and exothermic. Combined physicochemical characterization of hydrochar and batch experiment results suggest that the enhanced adsorption capacity was owing to boosting H-bonds, π-π electron-donor–acceptor, and hydrophobic interaction. This study suggested that ball-milling can be served as a facile, green, and cost-effective method to obtain modified hydrochar for the removal of pollutants in water.

Abstract Purpose In this study, first, second, third, and fourth-order derivative spectrophotometric methods utilizing the peak—zero (P—O) and peak-peak (P—P) techniques of measurement were developed for the determination of levofloxacin, norfloxacin, and moxifloxacin. These methods were applied to their combined pharmaceutical dosage form or individually for levofloxacin, norfloxacin, and moxifloxacin. Methods Linearity was established in the concentration range of 2–20 µg/mL. The procedures are simple, quick, and precise. The developed methods are sensitive, accurate, and cost-effective, demonstrating excellent correlation coefficients (R2 = 0.9998) and mean recovery values ranging from 99.20% to 100.08%, indicating a high level of precision. Results The developed approach was effectively employed to determine the levofloxacin, norfloxacin, and moxifloxacin content in commercially available pharmaceutical dosages. Conclusions Statistical analysis and recovery tests confirmed the method's linearity and accuracy. The results suggest that this method can be utilized for routine analysis in both bulk and commercial formulations. The simplicity, accuracy, and cost-effectiveness of the developed methods make them valuable for pharmaceutical analysis.

Purpose: In this study, first, second, third, and fourth-order derivative spectrophotometric methods utilizing the peak—zero (P—O) and peak-peak (P—P) techniques of measurement were developed for the determination of levofloxacin, norfloxacin, and moxifloxacin. These methods were applied to their combined pharmaceutical dosage form or individually for levofloxacin, norfloxacin, and moxifloxacin. Methods: Linearity was established in the concentration range of 2–20 µg/mL. The procedures are simple, quick, and precise. The developed methods are sensitive, accurate, and cost-effective, demonstrating excellent correlation coefficients (R2 = 0.9998) and mean recovery values ranging from 99.20% to 100.08%, indicating a high level of precision. Results: The developed approach was effectively employed to determine the levofloxacin, norfloxacin, and moxifloxacin content in commercially available pharmaceutical dosages. Conclusions: Statistical analysis and recovery tests confirmed the method's linearity and accuracy. The results suggest that this method can be utilized for routine analysis in both bulk and commercial formulations. The simplicity, accuracy, and cost-effectiveness of the developed methods make them valuable for pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

The transition metals (Cu, Co and Mn) were used to dope nanozero-valent iron (nZ-VI), and iron-based bimetallic nZVI/Cu, nZVI/Co and nZVI/Mn catalysts were prepared for the activation o£ PMS to achieve the efficient degradation o£ norfloxacin (NOR). The effects of different transition metals, catalytic systems and transition metal doping mass ratios on the catalytic degradation performance of NOR were investigated. The results showed that the nZVI/Co-5%/PMS activated system achieved 84.4% NOR removal within 120 min when the doping amount of Co was 5%. The excellent activated degradation performance was mainly attributed to the introduetion of transition metal Co to inhibit the passivation and agglomeration of nZVL. [ABSTRACT FROM AUTHOR]

Quinolone antibiotics are a common class of antibiotics in the environment and have received considerable attention. In this study, three groups of mixed degradation strains targeting mixed quinolone antibiotics, norfloxacin (NOR), and enrofloxacin (ENR) were selected through screening, enrichment, and microbial diversity detection experiments. The strains screened in this study are divided into two categories through degradation efficiency experiments, community composition detection and functional enrichment analysis. In groups mix and ENR, the resistant bacteria are the main microorganisms and the degrading bacteria are the secondary ones, while in group NOR, the strains with degradation effects are the main ones, and the strains with resistance effects are the secondary ones. What's more, that carbon sources have little effect on the community composition of the quinolone antibiotic degrading and tolerant bacteria, the difference between groups is mainly controlled by the type of antibiotics. On this basis, we found the key to NOR degradation is the cleavage of carbon nitrogen bonds on the piperazine ring, followed by oxygenation and deethylation. Preliminary studies have confirmed that the optimal degradation conditions for NOR degrading strains, and also found that environmental factors did not significantly affect the degradation efficiency of the Mix and NOR degrading strains, which indicating that the mixed bacteria can degrade NOR in different real environments effectively such as tap water, seawater, river water, and lake water. This manuscript is the first report on a mixed strain of quinolone antibiotic microbial degradation, and it is also the study with the highest NOR degradation efficiency among known reports. It has great research value for the co-metabolism and biodegradation of quinolone antibiotics in the environment. [ABSTRACT FROM AUTHOR]

The effect of silver nanoparticles and surfactant micelles on their joint presence on the intensity of the sensitized fluorescence of the norfloxacin complex with the Tb3+ ion is studied. It is shown that the intensity of the intrinsic fluorescence of norfloxacin and its complex with Tb3+ ions in the presence of silver nanoparticles decreases slightly. It is found that, in the presence of dodecyl sulfate micelles, a modification of the surface of silver nanoparticles occurs, which is accompanied by a change in the ζ-potential of the nanoclusters. Additions of surfactant-modified silver nanoparticles to aqueous solutions of terbium chelate contribute to an 11-fold increase in the intensity of the sensitized fluorescence. An increase in the efficiency of intramolecular energy transfer in the Tb3+ complex with norfloxacin in the presence of silver nanoparticles and dodecyl sulfate micelles made it possible to propose a method for the fluorimetric determination of the antibiotic in natural water in the concentration range 2 × 10–7−1 × 10–5 M. The equation of the calibration graph is y = 1.0 × 107x − 1.0, R2 = 0.991, the limit of detection is 5 × 10–8 M (3σ). [ABSTRACT FROM AUTHOR]

One-step carbonization was explored to prepare biochar using the residue of a traditional Chinese herbal medicine, Atropa belladonna L. (ABL), as the raw material. The resulting biochar, known as ABLB4, was evaluated for its potential as a sustainable material for norfloxacin (NOR) adsorption in water. Subsequently, a comprehensive analysis of adsorption isotherms, kinetics, and thermodynamics was conducted through batch adsorption experiments. The maximum calculated NOR adsorption capacity was 252.0 mg/g at 298 K, and the spontaneous and exothermic adsorption of NOR on ABLB4 could be better suited to a pseudo-first-order kinetic model and Langmuir model. The adsorption process observed is influenced by pore diffusion, π–π interaction, electrostatic interaction, and hydrogen bonding between ABLB4 and NOR molecules. Moreover, the utilization of response surface modeling (RSM) facilitated the optimization of the removal efficiency of NOR, yielding a maximum removal rate of 97.4% at a temperature of 304.8 K, an initial concentration of 67.1 mg/L, and a pH of 7.4. Furthermore, the biochar demonstrated favorable economic advantages, with a payback of 852.5 USD/t. More importantly, even after undergoing five cycles, ABLB4 exhibited a consistently high NOR removal rate, indicating its significant potential for application in NOR adsorption. [ABSTRACT FROM AUTHOR]

Antibiotics are commonly used to prevent and control aquaculture diseases. However, long-term overuse of antibiotics not only leaves residues but also leads to changes in the nitrogen cycle in water, which threatens the survival of aquaculture organisms. The current results showed that sulfamethoxazole had no significant effect on the nitrogen cycle process in the actual aquaculture concentration. The inhibitory effect of 1.05 mg/L norfloxacin on ammonia-oxidizing bacteria was significantly greater than that on ammonia-oxidizing archaea, and the gene abundance of AOB amoA on the 14th day increased by 2.48 times compared with the 7th day. Under the influence of 3.9 mg/L oxytetracycline, the gene abundance of AOB amoA decreased significantly, while the number of AOA amoA genes increased, suggesting that there may be functional redundancy between AOA and AOB. At the genus level in the norfloxacin group, the relative abundance of Sva0485 increased by 14.0% on the 7th day compared with the control group but decreased 12.77% in the addition group. The relative abundance of Firmicutes, another dominant species in the oxytetracycline group, was 25.9%. This study shows that the addition of antibiotics may have a negative effect on the nitrogen-cycling microorganisms in aquaculture water. [ABSTRACT FROM AUTHOR]

Biochar, as a potential adsorbent, has been widely employed to remove pollutants from sewage. In this study, a lignin-based biochar (CB-800) was prepared by a simple high-temperature pyrolysis using urban green waste (Cinnamomum camphora leaves) as a feedstock to remove norfloxacin (NOR) from water. Batch adsorption test results indicated that CB-800 had a strong removal capacity for NOR at a wide range of pH values. The maximum adsorption achieved in the study was 50.90 ± 0.64 mg/g at 298 K. The pseudo-first and second-order kinetic models and the Dubinin-Radushkevich isotherm fitted the experimental data well, indicating that NOR adsorption by CB-800 was a complex process involving both physi-sorption and chemi-sorption. The physical properties of CB-800 were characterized by SEM and BET. The mesoporous structures were formed hierarchically on the surface of CB-800 (with an average pore size of 2.760 nm), and the spatial structure of NOR molecules was more easily adsorbed by mesoporous structures. Combined with Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis, it was showed that the main NOR adsorption mechanisms by CB-800 included ion exchange, π-electron coordination, hydrogen bonding, and electrostatic adsorption. Meanwhile, the reduction of C = O and pyridine nitrogen, and the presence of C-F2, also indicated the occurrence of substitution, addition, and redox. This study not only determined the reaction mechanism between biochar and NOR, but also provides guidance to waste managers for the removal of NOR from water by biochar. It is envisaged that the results will broaden the utilization of urban green waste. [ABSTRACT FROM AUTHOR]

Background: Staphylococcus aureus is an adaptive and versatile microorganism that can cause a wide range of ailments, from intense and short-lived infections to persistent infections that are difficult to cure. Even though S. aureus infections could once be treated with ordinary antibiotics, the rise of drug-resistant organisms is currently a major issue. Numerous antibiotics were used to treat Staphylococcus aureus infections, but over time, the bacteria eventually developed resistance to multiple drugs. Since then, Methicillin-resistant Staphylococcus aureus (MRSA) strain-related nosocomial infections have increased in frequency. Recent advances in bioinformatics and silico screening have boosted our rate and chances of discovering medicinal metabolites. Objectives: In this study, we understand and analyse the binding efficiency of Staphylococcus aureus C0673 with three existing antibiotics employing molecular docking studies. Materials and Methods: The genomic sequence of Staphylococcus aureus C0673 is retrieved from the Ensemble bacteria database (GCA_00 0638495) and docked with three currently prescribed antibiotics, i.e., Gentamicin, Linezolid and Norfloxacin using HDOCK server. Results and Discussion: In the present study Gentamicin, Linezolid and Norfloxacin effectively bind with Staphylococcus aureus C0673. Based on the docking score, the efficiency of the compound against the bacterial protein was assessed. Gentamicin shows higher binding affinity when compared to the other two compounds. Hence, Gentamicin can be considered an eligible candidate by combining with novel medicines to treat the Multi-Drug Resistant protein of Staphylococcus aureus. Conclusion: From this research investigation, we conclude that multidrug resistant antibiotics efficiently bind with Staphylococcus aureus C0673. The results obtained from this study play a major role in the field of current bacterial informatics studies. [ABSTRACT FROM AUTHOR]

Antibiotics cannot be effectively removed by traditional wastewater treatment processes, and have become widespread pollutants in various environments. In this study, a Z-type heterojunction photo-catalyst Pg-C3N4 (PCN)/Nitrogen doped biochar (N-Biochar)/BiVO4 (NCBN) for the degradation of norfloxacin (NOR) was prepared by the hydrothermal method. The specific surface area of the NCBN (42.88 m2/g) was further improved compared to BiVO4 (4.528 m2/g). The photo-catalytic performance of the catalyst was investigated, and the N-Biochar acted as a charge transfer channel to promote carrier separation and form Z-type heterojunctions. Moreover, the NCBN exhibited excellent performance (92.5%) in removing NOR, which maintained 70% degradation after four cycles. The main active substance of the NCBN was •O2−, and the possible degradation pathways are provided. This work will provide a theoretical basis for the construction of heterojunction photo-catalysts. [ABSTRACT FROM AUTHOR]

In recent years, increasing interest has been accorded to polyester-based polymer microstructures, driven by their promising potential as advanced drug delivery systems. This study presents the preparation and characterization of new polymeric microparticles based on poly(ethylene brassylate-co-squaric acid) loaded with norfloxacin, a broad-spectrum antibiotic. Polymacrolactone was synthesised in mild conditions through the emulsion polymerization of bio-based and renewable monomers, ethylene brassylate, and squaric acid. The microparticles were obtained using the precipitation technique and subsequently subjected to comprehensive characterization. The impact of the copolymer/drug ratio on various properties of the new system was systematically evaluated, confirming the structure of the copolymer and the encapsulation of norfloxacin. The microspheres are approximately spherical and predominantly homogeneously distributed. The average hydrodynamic diameter of the microparticles falls between 400 and 2000 nm, a decrease that is observed with the increase in norfloxacin content. All samples showed good encapsulation efficiency and drug loading capacity, with the highest values obtained for microparticles synthesised using an equal ratio of copolymer and drug. In vitro drug release results disclose that norfloxacin molecules are released in a sustained biphasic manner for up to 24 h. Antimicrobial activity was also studied, with samples showing very good activity against E. coli and moderate activity against S. aureus and E. faecalis. In addition, HDFA human fibroblast cell cultures demonstrated the cytocompatibility of the microparticles. [ABSTRACT FROM AUTHOR]

Present photocatalysts for the synchronous cleanup of pharmaceuticals and heavy metals have several drawbacks, including inadequate reactive sites, inefficient electron-hole disassociation, and insufficient oxidation and reduction power. In this research, we sought to address these issues by using a facile solvothermal-photoreduction route to develop an innovative plasmonic S-scheme heterojunction, Au/MIL-101(Fe)/BiOBr. The screened-out Au/MIL-101(Fe)/BiOBr (AMB-2) works in a durable and high-performance manner for both Cr(VI) and norfloxacin (NOR) eradication under visible light, manifesting up to 53.3 and 2 times greater Cr(VI) and NOR abatement rates, respectively, than BiOBr. Remarkably, AMB-2's ability to remove Cr(VI) in a Cr(VI)-NOR coexistence system is appreciably better than in a sole-Cr(VI) environment; the synergy among Cr(VI), NOR, and AMB-2 results in the better utilization of photo-induced carriers, yielding a desirable capacity for decontaminating Cr(VI) and NOR synchronously. The integration of MOF-based S-scheme heterojunctions and a plasmonic effect contributes to markedly reinforced photocatalytic ability by increasing the number of active sites, augmenting the visible-light absorbance, boosting the efficient disassociation and redistribution of powerful photo-carriers, and elevating the generation of reactive substances. We provide details of the photocatalytic mechanism, NOR decomposition process, and bio-toxicity of the intermediates. This synergistic strategy of modifying S-scheme heterojunctions with a noble metal opens new horizons for devising excellent MOF-based photosystems with a plasmonic effect for environment purification. [ABSTRACT FROM AUTHOR]

Background: The present study was undertaken to study the percentage of pathogenic bacteria present in different fruit and vegetable samples available in the market in and around Kalaburagi, Karnataka, South India. Methods: A total of 940 different samples were collected from Kalaburagi, out of which 390 (23.84%) were fruits and 550 (35.27%) were vegetables. The pathogenic bacteria were isolated, by enrichment culture method using peptone water. The bacterial isolates were identified by convention microbial identification procedures. Result: Antibiotic resistant testing by disc diffusion method performed for E. coli, Salmonella and Shigella. Among the pathogens, E. coli (86.50%) of the isolates were resistant to Nalidixic acid while Imipenem and Trimethoprim-Sulfamethoxazole has the lowest resistance (19.84%), Salmonella (86.66%) isolates were resistant to Ciprofloxacin while Norfloxacin has the lowest resistance (4.76%) and Shigella (80.35%) isolates were resistant to Vancomycin while Amoxicillin has the lowest resistant (3.57%). Multiple drug resistance (MDR) was seen in E. coli at (38.88%), Salmonella at (26.66%) and Shigella at (10.71%) accordingly. The study therefore shown that E.coli, Salmonella and Shigella occur in Fruits and vegetables which collected from market place in Kalaburagi, Karnataka India, As per the results, adequate precaution should be taken while handles these fruits and vegetables. The antimicrobial resistance pattern shown by the isolates is an indication that adequate measurement needs to be taken to regulate the drug use in both humans and animals in order to minimize the risk of increasing antimicrobial resistance. [ABSTRACT FROM AUTHOR]

This study investigated the effects of levofloxacin (LEV) and norfloxacin (NOR) on Skeletonema costatum, focusing on cell growth, chlorophyll a (Chla) content, maximal quantum yield of PSII (Fv/Fm), protein content, enzyme activities of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GSH-PX), and the membrane lipid peroxidation product malondialdehyde (MDA) content were conducted to analyze the responses of S. costatum under LEV and NOR exposure. Cell growth, Chla content, Fv/Fm, protein content, enzyme activities, and MDA content were assessed to elucidate physiological changes. Both LEV and NOR inhibited S. costatum growth, except for 10 mg/L NOR, which promoted growth. Algal cells exhibited higher sensitivity to LEV, with 96h-IC50 values of 14.770 mg/L for LEV and 44.250 mg/L for NOR. Low NOR concentration (10 mg/L) increased Chla content, while high antibiotic concentrations (>20 mg/L for LEV, >100 mg/L for NOR) decreased Chla content and Fv/Fm, indicating an impact on photosynthesis. Elevated LEV and NOR levels reduced protein and MDA content but increased GR, SOD, and GSH activities, indicating induced oxidative stress. The study provides a comprehensive analysis of LEV and NOR effects on marine microalgae growth and underlying physiologicalmechanisms, shedding light on potential ecological risks posed by antibiotics inmarine ecosystems. [ABSTRACT FROM AUTHOR]

Background: Multi-Drug-ResistantKlebsiella pneumoniae (MDR K. pneumoniae) is considered as an important opportunistic pathogen, which causes life threatening infections. K. pneumoniae is known to causes life-threatening infections. Objective: The objective of this study is to detect some β-lactamase genes in Klebsiella pneumoniae. Methods: Thirty-five K. pneumoniae isolates were obtained from some hospitals in Baghdad City between October 2022 and February 2023. The identification of K. pneumoniae isolates was done phenotypically by the automated VITEK II system and genotypically by amplification of the rpob gene. The antibiotic susceptibility and detection of some β-lactamase genes were tested for all isolates. Results: The results showed that the K. pneumoniae isolates were resistant to most antibiotics used. A high percentage of K. pneumoniae isolates were resistant to cefixime, cefpodoxime, norfloxacin and doxycycline as 100% followed by ceftriaxone, ceftazidime, ticarcillin/clavulanate, ticarcillin, ceftazidime, tobramycin, and moxifloxacin (97.2%, 91.7%, 91.7%, 94.4%, 94.4%, and 94.4%, respectively). Furthermore, approximately 94.4% of the isolates were MDR. In addition, the molecular methods only detected the blaNDM and blaTEM genes as 33.3% and 75.6% of in the K. pneumoniae isolates, respectively, while the blaVIM, blaCTX−M, and blaKPC genes were not observed in K. pneumoniae isolates. Conclusions: β-lactam antibiotics, including carbapenems, are widely used to treat bacterial infections; however, an increase in antibiotic resistance due to β-lactamases limits the effectiveness of these antibiotics. Therefore, alternative treatment methods are required to control these resistant isolates. [ABSTRACT FROM AUTHOR]

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the title salt [systematic name: 4-(3-carboxy-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinolin-7-yl)piperazin-1-ium nitrate], C16H19FN3O3+·NO3−, proton transfer from nitric acid to the N atom of the piperazine ring of norfloxacin has occurred to form a molecular salt. In the extended structure, N—H...O hydrogen bonds link alternating cations and anions into [100] chains, which are reinforced by aromatic π–π stacking interactions between the quinoline moieties of the norfloxacinium cations.

BackgroundThe problem of medicine expiration presents a notable obstacle, resulting in considerable financial losses. Nevertheless, there is currently limited data indicating that certain medications do not experience a significant decrease in effectiveness after their expiration date. Therefore, the aim of the study was to assess the physico-chemical quality of expired fluoroquinolone antibiotics.MethodsThe expired samples of fluoroquinolone antibiotics were purposively collected from public hospitals in the Jimma zone of the Oromia regional state, Ethiopia. A World Health Organization quality evaluation sampling strategy was employed. Then, simple random sampling techniques were utilized for the selection of tablets for the laboratory quality control test. The assay, identification, and dissolution were performed in accordance with the United States Pharmacopeia (USP) guidelines, as well as failure mode and effect analysis (FMEA) techniques.ResultsThe finding revealed that about 100% (7/7) expired samples passed pharmacopeia quality specifications for identity and assay tests. However, of the seven expired brands, about 14.3% (1/7) of the sample (Code-002) was unable to release its API content within the USP criteria of 30 min. The risk-based quality evaluation revealed that assay was the most critical quality attributed to ciprofloxacin tablets (RPN = 189), followed by identity (RPN = 100). Assay was also the most critical quality attribute (RPN = 378), followed by identity (RPN = 100) for Norfloxacin tablets. The risk-based desirability function approach showed that 75% (3/4) of ciprofloxacin products were of good quality, and 25% (1) were found to be of acceptable quality, while the desirability function of norfloxacin tablets was found to be excellent 1 (33.3%), good 1 (33.3%), and acceptable 1 (33.3%).ConclusionThe study revealed that medications can maintain their quality beyond their labeled expiration date. By combining pharmacopeial standards with risk-based approaches like failure mode and effect analysis (FMEA), the study provides a comprehensive evaluation framework. This approach not only confirms the continued effectiveness of expired fluoroquinolone antibiotics but also underscores the potential waste reduction and cost-saving benefits. This could significantly contribute to addressing healthcare challenges in low-resource settings, promoting more efficient pharmaceutical resource utilization.

Background: Spontaneous Bacterial Peritonitis (SBP) is a bacterial infection of ascitic fluid occurring in patients suffering from cirrhosis and ascites exhibiting high short-term mortality rate and poor long-term prognosis. Aim and Objectives: Diagnosis based on ascitic fluid polymorphonuclear neutrophil count and culture was carried out. Norfloxacin is the current first-line prophylactic antibiotic treatment for SBP. The study aimed to compare the efficacy of norfloxacin and rifaximin in preventing SBP in patients with cirrhosis and ascites. Material and Methods: Total 66 patients were included, with 33 patients in each group. Patients in first group were administered 400 mg norfloxacin twice daily per orally, while other group was administered rifaximin 400 mg twice daily per orally for 3 months. The patients were followed up every month for three months to evaluate the signs and symptoms of SBP and other complications related to cirrhosis. Results: Mean age of all patients was 48.48 ± 10.44 years with majority being male. The most reported symptoms were decreased appetite and generalized weakness, while the most common sign detected was abdominal distention. Alcoholic liver disease was the most common etiology among patients with SBP. Hematological and biochemical parameters differed less significantly between two treatment groups, except for international normalized ratio values. At first, second and third follow-ups, more patients from norfloxacin administered group reported hepatic encephalopathy, gastrointestinal bleed, hepatorenal syndrome and SBP episodes than from rifaximin administered group. Conclusion: Overall, the study highlights effectiveness of rifaximin over norfloxacin in reducing the risk of complications in cirrhosis patients with ascites and Child Pugh Score > 9.

The dog was an essential source of Salmonella (S.) transmission. One hundred sixty-five rectal swabs were taken from apparently healthy dogs (90) and diarrheal dogs (75) in Baghdad province, Iraq. The Salmonella species was found using standard bacterial culture, biochemical tests, an analytical profile index (API-20), the VITEK2 compact system, and serotyping. Salmonella isolates were screened using the disc diffusion technique for susceptibility to ten antimicrobials. Findings indicated that the Salmonella species prevalence rate was 6.06% from dogs’ fecal samples, with three species identified; the most common serovar was S. Typhimurium, S. Enteritidis, and S. Muenchen, which was isolated for the first time from dogs in Iraq. Statistically significant risk factors concerning the diarrheal state, breed, feeding, and body condition were found. High occurrences were in diarrheal dogs (10.66%) compared to non-diarrheic dogs (2.22%); the large dog breed had a higher isolate rate of Salmonella than the small breed. Thin body condition dogs were more at risk than fatty dogs, and the dogs consuming uncooked feed had a higher percentage of Salmonella isolates and were more at risk than those consuming mixed food. Non-significant differences were found according to the gender, age, and educational status of dog owners. Salmonella isolates exhibited high resistance to cefotaxime, ampicillin, azithromycin, gentamycin, and tetracycline but were sensitive to norfloxacin. All the isolates were multidrug-resistant (MDR) except S. Muenchen. In conclusion, diarrheal and apparently healthy dogs carry and shed resistant Salmonella spp., a potential public health risk.

In this study, a zero‐gap flow‐through microfluidic reactor was constructed for the degradation of tetracycline and norfloxacin in water using a porous Ti/RuO2‐IrO2@Pt electrode as the anode and porous titanium plate as the cathode. The operation parameters included electrolyte type, electrolyte concentration, current density, initial concentration of pollutants and pH, were investigated. The degradation efficiency and energy consumption were calculated and compared with traditional electrolyzer. In the zero‐gap flow‐through microfluidic reactor, 100 % of both tetracycline and norfloxacin can be decomposed in 15 min, and high mineralization rate were achieved under the optimized reaction condition. And the reaction was consistent with pseudo‐first‐order kinetics with k value of 0.492 cm−1 and 1.010 cm−1, for tetracycline and norfloxacin, respectively. In addition, the energy consumption was 28.33 kWh ⋅ kg−1 TC and 8.36 kWh ⋅ kg−1 NOR, for tetracycline and norfloxacin, respectively, which was much lower than that of traditional electrolyzer. The LC–MS results showed that tetracycline underwent a series of demethylation, dehydration and deamination reactions, and the norfloxacin went through ring opening reaction, decarboxylation and hydroxylation reaction, and finally both produced CO2 and H2O. [ABSTRACT FROM AUTHOR]

In addition to the discovery of new (modified) potent antibiotics to combat antibiotic resistance, there is a critical need to develop novel strategies that would restrict their off‐target effects and unnecessary exposure to bacteria in our body and environment. We report a set of new photoswitchable arylazopyrazole‐modified norfloxacin antibiotics that present a high degree of bidirectional photoisomerization, impressive fatigue resistance and reasonably high cis half‐lives. The irradiated isomers of most compounds were found to exhibit nearly equal or higher antibacterial activity than norfloxacin against Gram‐positive bacteria. Notably, against norfloxacin‐resistant S. aureus bacteria, the visible‐light‐responsive p‐SMe‐substituted derivative showed remarkably high antimicrobial potency (MIC of 0.25 μg/mL) in the irradiated state, while the potency was reduced by 24‐fold in case of its non‐irradiated state. The activity was estimated to be retained for more than 7 hours. This is the first report to demonstrate direct photochemical control of the growth of antibiotic‐resistant bacteria and to show the highest activity difference between irradiated and non‐irradiated states of a photoswitchable antibiotic. Additionally, both isomers were found to be non‐harmful to human cells. Molecular modellings were performed to identify the underlying reason behind the high‐affinity binding of the irradiated isomer to topoisomerase IV enzyme. [ABSTRACT FROM AUTHOR]

The present study was conducted during August 2021 at Buffalo Research Station, Venkatarammanagudem of West Godavari District, Andhra Pradesh, India and was aimed to detect the presence of extended-spectrum beta-lactamases (ESBL) producing P. aeruginosa from sub-clinical mastitis that are apparently healthy Murrah buffaloes. Inflammation of the udder by microbial infection is one of the leading economic disease in the dairy sector. Most of the pathogens especially Pseudomonas aeruginosa are refractory to the antibiotic theraphy. Nowadays, the antimicrobial resistance owed by the bacteria is at an alarming rate. Pseudomonas aeruginosa, a multi drug resistant pathogen carry the extended spectrum beta lactamase genes in its plasmids and thus become resistant to antibiotic therapy. A total of 276 milk samples were collected from 69 milch animals in the month of August, 2021 comprising from all the four quarters of each buffalo. Nine (n=9) (3.26%) P. aeruginosa isolates were identified from the sub-clinical mastitis milk samples from the total 276 samples collected in the study. The isolates on morphological analysis were typical to P. aeruginosa. Seven isolates were positive for phenotypical beta-lactamases production. A total of 1 and 2 isolates were found reactive of the blaSHV and blaOXA genes, and two isolates harboured both blaSHV and blaOXA genes, respectively on PCR assay. No blaTEM gene was found in the isolates. Antibiogram of the ESBL producing P. aeruginosa isolates (n=7) possessed 100% resistance against most of the commonly used antimicrobials like ampicillin, amoxycillin, clindamycin, co-trimoxazole oxytetracycline, streptomycin and ceftriaxone (85%). The P. aeruginosa isolates were sensitive to amikacin (100%), ciprofloxacin (87.4%), gentamicin (84%), norfloxacin (84.8%) and enrofloxacin (82%). [ABSTRACT FROM AUTHOR]

Lead-based perovskites are highly susceptible to environmental influences, and their application in analytical chemistry, especially in aqueous solution, has been reported rarely. All-inorganic lead-free metal halide perovskites have been considered as a substitute for lead-based perovskites. Herein, a Cs2RbTbCl6 perovskite microcrystal (PMCs), which emits strong yellow-green fluorescence with a maximum emission wavelength at 547 nm, was for the first time synthesized and characterized. The Cs2RbTbCl6 PMCs could be well dispersed in N,N-dimethylacetamide (DMF), and its fluorescence could be significantly enhanced by the addition of norfloxacin (NOR) in the aqueous solution. We found that the Cs2RbTbCl6 PMCs can be used as fluorescent probes (excitation, 365 nm; emission, 547 nm) to selectively detect NOR in a concentration range from 10.0 to 200.0 μM with the limit of detection (LOD) being 0.04 μM. The Cs2RbTbCl6 PMCs could also be adsorbed on filter paper to fabricate as a fluorescent test paper for visual detection of NOR under 365-nm ultraviolet (UV) lamp irradiation. The proposed method has the potential to establish a new analytical method to visualize the detection of NOR in aqueous environments and also promotes the application of all-inorganic lead-free perovskites for analytical detection in aqueous environments. [ABSTRACT FROM AUTHOR]

The high frequency of infectious diseases has spurred research into effective tactics to combat microorganisms that are resistant to several drugs. The overproduction of the transmembrane efflux pump protein NorA, which may export hydrophilic fluoroquinolones, is a common mechanism of resistance in S. aureus strains. This work evaluated the antimicrobial activity of the ethanolic extract from the leaves of Croton heliotropiifolius (EECH) against different bacterial and fungal strains, as well as investigating its modulating effect on the resistance to norfloxacin in a Staphylococcus aureus SA1199B overproducing the NorA efflux pump. Microdilution assays were used to assess the EECH's antibacterial efficacy. The MIC of norfloxacin or ethidium bromide (EtBr) against the SA1199B strain was determined in the presence or absence of the EECH in order to assess the modifying influence on drug resistance. The EECH showed no activity against the Gram-positive and Gram-negative bacterial strains tested. The EECH also showed no antifungal activity against Candida albicans ATCC 10231. On the other hand, the extract reduced the MIC values for norfloxacin against SA1199B at subinhibitory concentrations. In addition, the EECH also reduced the MIC values of EtBr at subinhibitory concentrations, suggesting the occurrence of phytochemicals that inhibit efflux pumps. Molecular docking showed that retusin, a flavonoid found in the extract, could compete with norfloxacin at the orthosteric site of the NorA, indicating that it could be a potential efflux pump inhibitor. However, isolated retusin did not enhance the activity of norfloxacin or EtBr and it did not inhibit the EtBr efflux, showing that it is not a NorA inhibitor. Even though C. heliotropiifolius is a source of phytochemicals that function as adjuvants for norfloxacin, isolated retusin cannot be used in conjunction with norfloxacin to treat infections brought on by S. aureus that overproduces NorA. [ABSTRACT FROM AUTHOR]

g-C3N4/ZnxCd(1-x)S composites were synthesized by a simple hydrothermal method. The composites were characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, infrared spectroscopy, and electron micro-projective microscopy. According to the performance of ZnxCd(1-x)S for the photocatalytic degradation of norfloxacin under visible light in water, the best stoichiometric number of x was 0.5. The best photolytic norfloxacin degradation rate of g-C3N4/ZnxCd(1-x)S composites was 89.8%, which was obtained when the dosage ratio of g-C3N4 to ZnxCd(1-x)S was 1:1. The experiment was conducted to investigate the effect of pH on the catalyst to obtain the optimal NORF degradation environment pH in the range of 7 ± 0.3; by simulating the anions that may be contained in the actual environmental water, the results showed that the catalyst has a certain effect on the degradation of NORF when the water contains NO3−, Cl− and HCO3−. In addition, this study also obtained that the main active substances produced by the catalyst during degradation were electron–hole pairs by adding different trapping agents in the NORF removal experiments; and the catalyst was able to achieve a degradation rate of 86.1% after four cycles of the experiments, which proved that it had good stability. [ABSTRACT FROM AUTHOR]

The treatment of wastewater through the use of photocatalytic materials over semiconducting metal oxide has gained widespread interest as a promising new green and cheap technology. For the first time norfloxacin (NOR) antibiotic and methylene blue (MB) dye degradation was achieved by a simpler, cheaper, and faster technique for the preparation of NiO/ZnO heterostructure via NiO and its combined forms with ZnO catalysts under hydrothermal process. X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and X-ray photoelectron (XPS) spectroscopy were the techniques that were used to analyze the structure, morphology, and elemental contents, respectively. The Tauc plot using absorption spectra was used to determine the band energy value of pure NiO, ZnO, and NiO–ZnO catalysts. The results showed that the energy band gap of these materials was 3.15, 3.38, and 2.93 eV, respectively. All photocatalysts performed good efficiency within 50 min of irradiation, among these NiO/ZnO having superior activity (30 mg of catalyst, and 10 µM of dye and antibiotic). Under these conditions, the photocatalytic degradation efficiency of the produced NiO/ZnO materials for the NOR and MB dye was achieved at 96.73% and 97.38%, respectively. Inhibition of the recombination of electron-hole pairs by charge transfer processes may account for the high activity of the p-n-type NiO/ZnO heterostructures for the degradation of NOR and MB. Because of their strong photocatalytic activity, heterostructures based on semiconducting composites, such as NiO/ZnO, have great promise for use in future manufacturing processes aimed at cleaning our surroundings of harmful organic pollutants. [ABSTRACT FROM AUTHOR]

Paper-based test strips with on-site visual detection have become a hot spot in the field of target detection. Yet, low specific surface area and uneven deposition limit the further application of test strips. Herein, a novel "turn-on" ratio of molecularly imprinted membranes (Eu@CDs-MIMs) was successfully prepared based on a Eu complex-doped polyvinylidene fluoride membrane for the selective, rapid and on-site visual detection of norfloxacin (NOR). The formation of surface-imprinted polymer-containing carbon dots (CDs) improves the roughness and hydrophilicity of Eu@CDs-MIMs. Fluorescence lifetimes and UV absorption spectra verified that the fluorescence enhancement of CDs is based on the synergistic effect of charge transfer and hydrogen bonding between CDs and NOR. The fluorescent test strip showed a linear fluorescent response within the concentration range of 5–50 nM with a limit of detection of 1.35 nM and a short response time of 1 min. In comparison with filter paper-based test strips, Eu@CDs-MIMs exhibit a brighter and more uniform fluorescent color change from red to blue that is visible to the naked eye. Additionally, the applied ratio fluorescent test strip was combined with a smartphone to translate RGB values into concentrations for the visual and quantitative detection of NOR and verified the detection results using high-performance liquid chromatography. The portable fluorescent test strip provides a reliable approach for the rapid, visual, and on-site detection of NOR and quinolones. [ABSTRACT FROM AUTHOR]

The synthesis and antiplasmodial evaluation of new hybrids combining the pharmacophore structures of artemisinin, ciprofloxacin or norfloxacin, and 7-chloroquinoline are reported in this study. The first step for all of the syntheses is the obtainment of key piperazine esters intermediates bearing the drugs ciprofloxacin and norfloxacin. Using these platforms, 18 final compounds were synthesized through a multistep procedure with overall yields ranging between 8 and 20%. All compounds were screened for their antiplasmodial activity against the chloroquine-resistant Plasmodium falciparum FcB1 strain. Compounds 20, 21, 22, and 28, bearing an artesunate fragment with ciprofloxacin, exhibited IC50 values in the range of 3.5–5.4 nM and excellent selectivity indices. Among the compounds bearing the artesunate moiety on the norfloxacin, two of them, 23 and 24, afforded IC50 values of 1.5 nM and 1.9 nM, respectively. They also showed excellent selectivity indices. The most potent compounds were also evaluated against the CQ-resistant Dd2 strain of Plasmodium falciparum, demonstrating that those compounds incorporating the artesunate fragment were the most potent. Finally, the combination of artesunate with either ciprofloxacin or norfloxacin moieties in a single molecular entity proved to substantially enhance the activity and selectivity when compared to the administration of the unconjugated counterparts artesunate/ciprofloxacin and artesunate/norfloxacin. [ABSTRACT FROM AUTHOR]