Disinfection Treatment Research Articles

Antibacterial Activity of Brass against Antibiotic-Resistant Bacteria following Repeated Exposure to Hydrogen Peroxide/Peracetic Acid and Quaternary Ammonium Compounds.

Copper-containing materials are attracting attention as self-disinfecting surfaces, suitable for helping healthcare settings in reducing healthcare-associated infections. However, the impact of repeated exposure to disinfectants frequently used in biocleaning protocols on their antibacterial activity remains insufficiently characterized. This study aimed at evaluating the antibacterial efficiency of copper (positive control), a brass alloy (AB+®) and stainless steel (negative control) after repeated exposure to a quaternary ammonium compound and/or a mix of peracetic acid/hydrogen peroxide routinely used in healthcare settings. A panel of six antibiotic-resistant strains (clinical isolates) was selected for this assessment. After a short (5 min) exposure time, the copper and brass materials retained significantly better antibacterial efficiencies than stainless steel, regardless of the bacterial strain or disinfectant treatment considered. Moreover, post treatment with both disinfectant products, copper-containing materials still reached similar levels of antibacterial efficiency to those obtained before treatment. Antibiotic resistance mechanisms such as efflux pump overexpression did not impair the antibacterial efficiency of copper-containing materials, nor did the presence of one or several genes related to copper homeostasis/resistance. In light of these results, surfaces made out of copper and brass remain interesting tools in the fight against the dissemination of antibiotic-resistant strains that might cause healthcare-associated infections.

Chlorine dioxide may be an alternative to acidification and chlorination for drinking water chemical disinfection in dairy beef bulls

Alternative water disinfectants to chlorination need to be identified because its effectiveness is limited by water pH and potentially carcinogen by−products resulted from chlorination and organic compound reaction. The first study aimed to evaluate the effect of different drinking water chemical disinfection treatments on water quality, its potential hazard effects on animal health, water and feed consumption, and apparent total tract digestibility in dairy beef bulls fed high-concentrate diets. For 224 days, 24 Holstein bulls (176 ± 16.3 kg BW, and 149 ± 5.8 days of age) were individually assigned to one of four treatments with different drinking water chemical disinfectants: without disinfection (CTR); acidification and chlorination (ACCHL; 0.65 mL/L H3PO4 and 0.14 mL/L NaClO 15%); hydrogen peroxide (PER; 0.15 mL/L); and chlorine dioxide (DIO; 2.50 mL/L). Data were analysed with a mixed-effects model. Treatments affected the chemical characteristics of the water: in ACCHL, pH was 6.60 and free residual chlorine was 0.75 mg/L; in PER, H2O2 was 10.6 mg/L; and in DIO, ClO2 was 0.52 mg/L. Water physicochemical quality parameters in all treatments were below maximal thresholds established for safe water consumption by the Water Safety Royal Decree (RD 140/2003). In addition, the total coliform count of treated waters was reduced (P = 0.01) compared with CTR; moreover, ACCHL and DIO treatments were more effective in reducing total coliform count than PER. Dry matter intake tended (P = 0.07) to increase in DIO compared with CTR. Treatments did not affect blood parameters nor apparent total tract digestibility. The second study aimed to evaluate the potential benefit on animal performance of two drinking water disinfectants under commercial conditions in dairy beef crossbred Holstein bulls fed high-concentrate diets. Ninety-six animals (307 ± 4.4 kg BW, and 224 ± 1.8 days of age) were allocated to six pens for 140 days and assigned to one of two treatments: ACCHL, most common water disinfectant, and DIO. Data were analysed with a mixed-effects model. Water total coliform count and water consumption were similar between treatments. Concentrate intake was greater (P = 0.02) in ACCHL for the last 14 study days. Growth performance and carcass quality were similar between treatments. In summary, acidification and chlorination, H2O2, and ClO2 as drinking water disinfectants in dairy beef bulls had good disinfecting activity without detrimental effects on health and nutrient digestibility, and performance.

Topographic analysis of fiber posts after surface disinfection with different methods

Aims: This study aims to comprehensively examine the surface morphology of fiber posts after undergoing various disinfection methods, utilizing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Materials and Methods: Twenty-one fiber posts were randomly allocated into seven experimental groups, each consisting of three samples. The disinfection methods employed were as follows: GC - no disinfection treatment; GAL - immersion in 70% alcohol, following the manufacturer's recommended protocol; GHP - soaking in 2.5% sodium hypochlorite for a duration of 10 minutes; GCL - soaking in 2% chlorhexidine gluconate for a period of five minutes; GAC - 30-second etching with 35% phosphoric acid; GPH - soaking in 10% hydrogen peroxide for a duration of 20 minutes; and GSL - autoclave sterilization. Following the disinfection procedures, SEM was employed to scrutinize the surface topography of the posts, while EDX was utilized to identify the chemical elements present on the sample surfaces. Subsequently, a descriptive analysis was conducted on the SEM images and EDX data. Results: SEM analysis revealed that all groups exhibited regions with epoxy resin-coated fibers alongside sections with exposed glass fibers. Analysis of the EDX data indicated that there were no significant differences in the predominant chemical elements across the groups. Carbon (C) and oxygen (O) registered the highest peaks, followed by silicon (Si), zirconium (Zr), sodium (Na), aluminum (Al), and calcium (Ca). Conclusions: The disinfection methods under investigation did not induce substantial alterations in the surface morphology of the fiber posts.

Sewage Sludge Increased Lettuce Yields by Releasing Valuable Nutrients While Keeping Heavy Metals in Soil and Plants at Levels Well below International Legislative Limits

Sewage sludge can be used as an organic amendment as long as it is ensured that there is no risk of environmental contamination or risk to public health. In this study, sewage sludge from two wastewater treatment plants (WWTPs) subjected to two disinfection and stabilization treatments [40% (mass/mass), calcium oxide, and calcium hydroxide] and their respective untreated sewage sludge were used. Three control treatments were also added: conventional farmyard manure (FYM), a nitrogen (N) mineral fertilizer (ammonium nitrate 34.5% N) applied at a rate of 50 kg N ha−1 (N50) (the same rate of all organic amendments), and an unfertilized control (N0), totaling nine treatments. Lettuce (Lactuca sativa L.) was cultivated in pots for two growing cycles. The dry matter yield (DMY) was higher in the N50 treatment (13.5 and 10.6 g plant−1 in the first and second growing cycles, respectively), followed by sewage sludge (10.8 to 12.4 and 8.4 to 8.7 g plant−1), FYM (8.5 and 7.2 g plant−1), and the control (7.7 and 6.0 g plant−1). The DMY was related to the N provided by the different treatments, assessed by the N and nitrate concentrations in tissues, N uptake, and apparent N recovery (ANR). Sewage sludge, due to its high N concentration and low carbon (C)/N ratio, mineralized rapidly, providing a significant amount of N to plants, as well as other nutrients, such as phosphorus (P) and boron (B). FYM, with a higher C/N ratio, provided less N to plants, also due to the short duration of the lettuce growing cycle. Alkalized sewage sludge increased soil pH and calcium (Ca) availability for plants. Fertilizer treatments minimally influenced cationic micronutrients. Heavy metals in the initial sewage sludge were below the threshold values established in international legislation, and the levels in soil and lettuce tissues were generally not higher than those in other treatments. Both of the sewage sludges used in this study showed high fertilizing value and very reactive behavior, making nutrients available much more quickly than FYM. This information is relevant to consider in defining their agricultural use.

Optimization of anaerobic soil disinfestation against Verticillium wilt in strawberry cultivation using local agrowastes as amendments.

The study explores anaerobic soil disinfection as an alternative to soil fumigants for controlling Verticillium wilt in strawberry crops. For this purpose, two agrowastes close to the strawberry-growing areas of Huelva province were tested as potential amendments for the control of Verticillium wilt: rice bran and residual strawberry extrudate. Furthermore, two application rates were evaluated: 13.50 and 20.00 t/ha for the rice bran and 16.89 and 25.02 t/ha for residual strawberry extrudate. Amended and anaerobically disinfested soils were compared with a non-amended soil under anaerobic conditions, a soil treated with the chemical fungicide metam sodium and an untreated soil. One week before the start of disinfection treatment, these soils were artificially inoculated with 250 microsclerotia/g dry soil of Verticillium dahliae. After disinfestation treatments, pathogens were quantified, and strawberry plants were cropped in a growth chamber to further evaluate Verticillium wilt severity, which was measured with a symptom scale in the same potting soils. Measurements of the anaerobic condition, pH and microbial population densities were performed, and the results showed significant differences between the different amendments. In addition, the treatment with rice bran at 20 t/ha recorded the lowest population density of V. dahliae. Likewise, it was possible to achieve a reduction in foliar disease severity in all amended treatments in similar percentage to those obtained by chemical treatment. These results suggest potential application of this technique for the control of Verticillium wilt in the strawberry-growing area of Huelva, reducing the use of chemical fumigants.

Spraying zinc oxide nanoparticles on pistachios (Pistacia vera L.) for preservation in cold storage

ABSTRACT The ability of zinc oxide nanoparticles to extend the shelf life of fresh pistachios in polyethylene packages in cold storage was evaluated. Independent variables were the type and concentration of the disinfectant (0.5%, 1%, 1.5%, and 2% nano-ZnO and 2% peracetic acid) and storage time (at harvest, 25, 50 and 75 days after harvest). Aflatoxin was not detected in the kernels of the disinfectant treatments after storage. A decrease occurred in firmness, chlorophylls and carotenoids in hulls and kernels over time. Phenolics and flavonoids of kernels decreased, parallel to a decrease in weight. Nano-ZnO (2%) prevented this reduction well. In hulls and kernels, nano-ZnO (2%) revealed the highest anthocyanin. Antioxidant activity in kernels remained stable or even increased in response to ZnO (1.5%) on day 75. All ZnO treatments prevented ion leakage while limiting hydrogen peroxide and malondialdehyde production in hulls. Peracetic acid reduced polyphenol oxidase activity on 75th day. ZnO (1% and 1.5%) and peracetic acid increased phenylalanine ammonia lyase activity. On 75th day, ZnO-treated samples had higher peroxidase activity. All ZnO treatments, especially 1.5% and 2%, prevented the loss of quality in hulls, shells, taste, and aroma. Nano-ZnO (2%) can be recommended for fresh pistachio preservation in cold storage.

A Photonic Immunosensor Detection Method for Viable and Non-Viable E. coli in Water Samples.

Detection and enumeration of coliform bacteria using traditional methods and current molecular techniques against E. coli usually involve long processes with less sensitivity and specificity to distinguish between viable and non-viable bacteria for microbiological water analysis. This approach involves developing and validating an immunosensor comprising ring resonators functionalized with specific antibodies surrounded by a network of microchannels as an alternative method for detecting and indirectly enumerating Escherichia coli in samples of water for consumption. Different ELISA assays were conducted to characterize monoclonal and polyclonal antibodies selected as detection probes for specific B-galactosidase enzymes and membrane LPS antigens of E. coli. An immobilization control study was performed on silicon nitride surfaces used in the immunosensor, immobilized with the selected antibodies from the ELISA assays. The specificity of this method was confirmed by detecting as few as 10 CFU/mL of E. coli from viable and non-viable target bacteria after applying various disinfection methods to water samples intended for human consumption. The 100% detection rate and a 100 CFU/mL Limit of Quantification of the proposed method were validated through a comprehensive assessment of the immunosensor-coupled microfluidic system, involving at least 50 replicates with a concentration range of 10 to 106 CFU/mL of the target bacteria and 50 real samples contaminated with and without disinfection treatment. The correlation coefficient of around one calculated for each calibration curve obtained from the results demonstrated sensitive and rapid detection capabilities suitable for application in water resources intended for human consumption within the food industry. The biosensor was shown to provide results in less than 4 h, allowing for rapid identification of microbial contamination crucial for ensuring water monitoring related to food safety or environmental diagnosis and allowing for timely interventions to mitigate contamination risks. Indeed, the achieved setup facilitates the in situ execution of laboratory processes, allowing for the detection of both viable and non-viable bacteria, and it implies future developments of simultaneous detection of pathogens in the same contaminated sample.

Unlocking Novel Anticancer Strategies: Bioactive Hydrogels for Local Delivery of Plasma-Derived Oxidants in an In Ovo Cancer Model.

Cold atmospheric plasma (CAP) is a tool with the ability to generate reactive oxygen and nitrogen species (RONS), which can induce therapeutic effects like disinfection, wound healing, and cancer treatment. In the plasma oncology field, CAP-treated hydrogels (PTHs) are being explored for the local administration of CAP-derived RONS as a novel anticancer approach. PTHs have shown anticancer effects in vitro, however, they have not yet been studied in more relevant cancer models. In this context, the present study explores for the first time the therapeutic potential of PTHs using an advanced in ovo cancer model. PTHs composed of alginate (Alg), gelatin (Gel), Alg/Gel combination, or Alg/hyaluronic acid (HA) combination are investigated. All embryos survived the PTHs treatment, suggesting that the in ovo model could become a time- and cost-effective tool for developing hydrogel-based anticancer approaches. Results revealed a notable reduction in CD44+ cell population and their proliferative state for the CAP-treated Alg-HA condition. Moreover, the CAP-treated Alg-HA formulation alters the extracellular matrix composition, which may help combat drug-resistance. In conclusion, the present study validates the utility of in ovo cancer model for PTHs exploration and highlights the promising potential of Alg-based PTHs containing HA and CAP-derived RONS for cancer treatment.

Culture protocols of the Metallic Shiner for ornamental aquaculture

AbstractObjectiveWhile North American fishes are often overlooked by the ornamental fish industry, there is growing interest in fishes native to the southeastern USA, a hot spot for fish diversity. The Metallic Shiner Pteronotropis metallicus, a small‐bodied leuciscid native to Florida and Georgia, is sometimes available in the ornamental fish trade through wild collection and limited captive production. This species exhibits a distinctive color pattern straddling the lateral line: a dorsal pink to red line, fading to a black to blue stripe. This group of minnows is largely unknown to ornamental aquaculture and lacks defined culture protocols. Our objective was to develop culture protocols for the Metallic Shiner.MethodsFollowing collection of wild broodstock, we used routine culture methods to experimentally determine substrate preference, egg incubation, egg disinfection, larval feeding, and larval development.ResultMetallic Shiner spawning was more successful on yarn mops compared with other media, with average output of >50 embryos per tank per day. Hatching success was similar for static incubators (24%) and upwelling incubators (20%) and was also similar among egg disinfection treatments (iodine, hydrogen peroxide, and formalin). Larval feeding regimes altered survival, with Otohime A1 exhibiting higher survival (44%) over 14 days posthatch (dph) and better growth than other feeding regimes. During the developmental trial with water temperature at a relatively constant 25°C, length increased from 5 mm notochord length (4 dph) to 8.7 mm standard length (45 dph), with significant milestones occurring at 4 dph (swim bladder inflation), 16 dph (flexion), and 23 dph (hypural plate formation).ConclusionThese data provide basic culture information for the Metallic Shiner while also providing a place of reference to begin investigating culture protocols for related species, including species of conservation concern.

Efficacy of disinfectants and heat treatments against green mould in casing soil and button mushroom (Agaricus bisporus) yield

Button mushroom (Agaricus bisporus) is the predominant mushroom species cultivated around the world. In the button mushroom cultivation, casing soil is one of the main substrate inducing emergence of mushrooms but presence of Trichoderma aggressivum f. aggressivum (causal agent of green mould disease) in casing soil causes devastating yield losses. However, little is known about management of the green mould in button mushroom cultivation. The aim of this study was to examine efficacy of several disinfectants and heat treatments against T. aggressivum f. aggressivum in casing soil and mushroom yield. In this respect, by considering yield (total amount of sporophores) values, in vivo experiments were separately set up according to randomized block design with three replications. As a result, compared to controls, disinfectants [hydrogen peroxide (H202), formaldehyde (CH2O), sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl)] and heat treatments (60, 90 and 120 °C) significantly (P˂0.01) increased mushroom yields up to 18.74 and 24.06% in the treated plots, respectively. Biological efficiency values ranged from 87.16 to 105.72% in the disinfectant treatments, while they varied from 93.15 to 95.68% in the heat treatments. However, applications of the disinfectants at high doses had negative influence on growth of A. bisporus. The overall results suggest that the tested disinfectants and heat treatments may significantly increase button mushroom yield by suppressing development of T. aggressivum f. aggressivum in casing soil. The present study not only reveals management practices that can be used against the green mould in the in vivo but also presents new knowledge for mushroom industry.

Effective of different industrial disinfection in subzero cold-chain environment

Effective disinfection methods are crucial in the cold chain transportation process of food due to the specificity of temperature and the diversity of contaminated flora. The objective of this study was to investigate the sanitizing effect of different disinfectants on various fungi at – 20 °C to achieve accurate disinfection of diverse bacterial populations. Peracetic acid, hydrogen peroxide, and potassium bisulfate were selected as low-temperature disinfectants and were combined with antifreeze. The sanitizing effect of these cryogenic disinfectants on pathogens such as Bacillus subtilis black variant spores (ATCC9372), Staphylococcus aureus (ATCC 6538), Candida albicans (ATCC 10231), Escherichia coli (8099), and poliovirus (PV-1) was sequentially verified by bactericidal and virus inactivation experiments. After a specified time of disinfection, a neutralizing agent was used to halt the sanitizing process. The study demonstrates that different disinfectants exhibit selective effects during the low-temperature disinfection process. Peracetic acid, hydrogen peroxide, and potassium monopersulfate are suitable for the low-temperature environmental disinfection of bacterial propagules, viruses, and fungal contaminants. However, for microorganisms with strong resistance to spores, a low-temperature disinfectant based on peracetic acid should be chosen for effective disinfection treatment. Our results provide a valuable reference for selecting appropriate disinfectants to sanitize various potential pathogens in the future.

Laser-induced 2D/0D graphene-nanoceria freestanding paper-based films for on-site hydrogen peroxide monitoring in no-touch disinfection treatments

A one-shot CO2 laser-based strategy to generate conductive reduced graphene oxide (rGO) decorated with nanoceria (nCe) is proposed. The 2D/0D rGO-nCe films, integrated as catalytic sensing layers in paper-based sensors, were employed for on-site monitoring of indoor fogging treatments against Listeria monocytogenes (Lm), a ubiquitous pathogenic bacterium. The rGO-nCe laser-assisted synthesis was optimized to preserve the rGO film morphological and electron-transfer features and simultaneously integrate catalytic nCe. The films were characterized by microscopical (SEM), spectroscopical (EDX, Raman, and FTIR), and electrochemical techniques. The most performing film was integrated into a nitrocellulose substrate, and the complete sensor was assembled via a combination of xurography and stencil printing. The rGO-nCe sensor's catalytic activity was proved toward the detection of H2O2, obtaining sensitive determination (LOD = 0.3 µM) and an extended linear range (0.5–1500 µM). Eventually, the rGO-nCe sensor was challenged for the real-time continuous monitoring of hydrogen peroxide aerosol during no-touch fogging treatment conducted following the EU’s recommendation for biocidal product use. Treatment effectiveness was proved toward three Lm strains characterized by different origins, i.e., type strain ATCC 7644, clinical strain 338, and food strain 641/6II. The sensor allows for discrimination and quantification treatments at different environmental biocidal amounts and fogging times, and correlates with the microbiological inhibition, promoting the proposed sensor as a useful tool to modulate and monitor no-touch treatments.Graphical

Effects of sterilization and disinfection methods on digitally designed surgical implant guide accuracy: An in vitro study.

Surgical guides are commonly used to assist with dental implant placement. This study investigated the effects of five sterilization and disinfection methods on the accuracy of implant guides. Thirty surgical guides (five in each group) were designed and printed (with digital light processing technology) using different sterilization or disinfection methods categorized into six groups: hydrogen peroxide sterilization (group one); glutaraldehyde sterilization (group two); autoclaving (group three); plasma sterilization (group four); iodophor disinfection (group five); and blank group (group six). Verification was determined using three methods: distance and angle between the cross-shaped marks, deformation after superimposing the guides, and displacement and axial changes in the virtual implant. After disinfection and sterilization, the guides in the autoclaving and iodophor groups showed a more pronounced color change and the guidein the autoclaving group had visible cracks. More significant changes were observed in the H2O2, glutaraldehyde, autoclaving, and iodophor groups regarding deformation after superimposing the guides and the distance and angle between the cross-shaped marks. The average labial deformation values (mm) of the first through fifth groups of guides were 0.283, 0.172, 0.289, 0.153, and 0.188, respectively. All groups were statistically different from the blank group for displacement and axial changes of the virtual implant (p < 0.05). The sizes of almost all surgical guides changed after sterilization and disinfection treatments, with between-group differences. Plasma sterilization was more suitable for surgical guide sterilization because of the smaller deformations after treatment.

Long-term disinfectant exposure on intestinal immunity and microbiome variation of grass carp

The gut microbiome is crucial in maintaining fish health homeostasis. Disinfectants can kill important pathogens and disinfect fish eggs, yet their effect on the immune pathways and intestinal microbiome in healthy fish remains unknown. In this study, we investigated the effects of two disinfectants on the transcriptome profiles, immunological response, and gut microbiota dynamics of grass carp over a four-week trial. In particular, aquatic water was disinfected with 80 μg/L glutaraldehyde or 50 μg/L povidone-iodine. We found that glutaraldehyde and povidone-iodine induced gut antioxidant system and depressed the function of grass carp digestive enzymes. The results of the 16S rDNA high-throughput sequencing identified a reduction in the diversity of grass carp gut microbiota following the disinfectant treatment. Moreover, transcriptome profiling revealed that disinfectant exposure altered the immune-related pathways of grass carp and inhibited the expression of inflammation and tight junction related genes. Finally, the histopathological observation and apoptosis detection results suggested that the long-term diet of disinfectant destroyed intestinal structural integrity and promoted apoptosis. In conclusion, long-term exposure to disinfectants was observed to reduce oxidation resistance, suppress the immune response, dysbiosis of the intestinal flora, and resulted in increasing the apoptosis in intestinal of grass carp.

Assessing the effectiveness and mechanisms of Fe/PS, Fe/H2O2, and O3 treatment for water disinfection: Spotlight on VBNC bacteria

Advanced oxidation processes (AOPs) exhibit significant potential for water disinfection due to their generation of large quantities of highly oxidizing free radicals. However, the neglect of viable but nonculturable (VBNC) cells obscures their true disinfection efficacy and potential environmental health risks. Therefore, the study evaluated the disinfection effectiveness and mechanisms of typical AOPs, including Fe/H2O2, Fe/persulfate (PS), and O3, from the perspective of the production of VBNC bacteria. The results indicate that Fe/PS exhibits the strongest bacterial inactivation rate (99.94%), and the cells lose their ability to reactivate. Fe/H2O2 and O3 induce more cells to enter the VBNC state compared to Fe/PS. Moreover, different AOPs result in varying levels of free radical production and utilization efficiency, with SO4•− and O3 exhibiting greater selectivity in deactivating bacteria compared to HO•. The inhibition of VBNC bacteria production by Fe/PS treatment may be attributed to the combined action of HO• and SO4•− on microorganisms, leading to oxidative stress and metabolic disruption in bacteria through the inhibition of biofilm formation and aminoacyl-tRNA biosynthesis (p < 0.05), thereby causing direct bacterial death rather than entry into the VBNC state. In contrast, Fe/H2O2 and O3 result in the upregulation of the metabolism of alanine, aspartate, and glutamate, as well as styrene degradation capacity by the bacteria, leading to the production of more VBNC bacteria. Overall, the study offers insights into mitigating potential biological risks in water disinfection and developing environmentally friendly and efficient disinfection technologies.

Evaluation of combined disinfection methods of infectious myonecrosis virus (IMNV) in seawater using Pacific white shrimp (Penaeus vannamei)

The global spread of infectious myonecrosis virus (IMNV) poses a serious threat to the shrimp aquaculture industry and urgent actions are needed to control its transmission and prevalence. Aquaculture water serves as an important route of IMN transmission, and disinfection of aquaculture water is crucial to ensure the health and stable production of shrimp. In this study, we introduced the purified IMNV into seawater and then subjected the seawater to different disinfection treatments (PMS, PMS + PVP-I and ClO2 + PVP-I) before culturing shrimp. By performing RT-qPCR tests on both the seawater and Pacific white shrimp (Penaeus vannamei) samples, we evaluated the effectiveness of the different disinfection methods in eradicating IMNV from the seawater. The results showed that peroxymonosulfate (PMS) could effectively reduce the viral load of IMNV in seawater samples. The combined disinfection approach (10 ppm) of PMS disinfection (combined with povidone‑iodine) followed by a standing time of at least 2 days, or 10 ppm chlorine dioxide disinfection (combined with povidone‑iodine) followed by a standing time of at least 4 days, were found to be successful in the efficient disinfection of IMNV. This research provides a method to effectively remove IMNV from marine aquaculture water, thereby contributing to reducing the risk of IMN disease transmission and providing a sound basis for the sustainable and healthy development of the shrimp aquaculture industry.

Determination of the possibility of the synthesis of Zn-Al layered double hydroxides, intercalated with peroxyanions, as a perspective solid disinfectant

Infectious diseases in the modern world pose a significant threat to humanity in the form of epidemics and pandemics. To prevent and combat them, it is necessary to carry out antiseptic and disinfectant treatments of various environments, household and industrial surfaces, as well as wounds of various origins. Double-layer hydroxides intercalated with peroxyanions as active oxygen compounds are promising materials for this. In order to determine the possibility of obtaining Zn-Al double-layer hydroxide intercalated with peroxylactic acid anions, samples were synthesized by the method of chemical co-precipitation in the presence of peroxylactic acid at controlled pH (8, 10) and t=20 ℃. The properties of the synthesized samples were investigated. The content of active oxygen (in terms of H2O2) was determined by the method of iodometric titration with the calculation of the percentage of hydrogen peroxide that was intercalated in double layered hydroxides, remained in the mother solution or was lost. The crystal structure was studied by X-ray phase analysis, the yield of samples was determined gravimetrically, and sedimentation was determined by measuring and normalizing the thickness of the sediment layer. It was found that the samples synthesized at pH=8 and 10 are biphasic and consist of an oxide phase and a double-layer hydroxide phase. The determined content of active oxygen (in terms of H2O2) in the samples synthesized at pH=8 (0.533 %) and at pH=10 (0.876 %) confirms the success of the synthesis of Zn-Al-peroxylactate double layered hydroxides. Synthesis at elevated pH is promising. A low percentage of H2O2 intercalation was revealed – 4.03–6.54 %, the majority of hydrogen peroxide (82.36-94.44 %) remains in the mother solution. The yield of the synthesized samples was determined to be 61.9 % and 79.5 % at synthesis pH of 10 and 8, respectively. The sedimentation properties of the samples were studied and their improvement was shown when the pH of the synthesis was increased

Formation potential of disinfection byproducts during chlorination of petroleum hydrocarbon-contaminated drinking water

Recent leaks of underground fuel storage tanks in the Pearl Harbor region have led to direct release of un-weathered petroleum hydrocarbons (PHCs) into drinking water sources, which then directly underwent chlorination disinfection treatment. Since the control of disinfection byproducts (DBPs) traditionally focuses natural organic matters (NOM) from source water and little is known about the interactions between free chlorine and un-weathered PHCs, laboratory chlorination experiments in batch reactors were conducted to determine the formation potential of DBPs during chlorination of PHC-contaminated drinking water. Quantitative analysis of regulated DBPs showed that significant quantities of THM4 (average 3,498 μg/L) and HAA5 (average 355.4 μg/L) compounds were formed as the result of chlorination of un-weathered PHCs. Amongst the regulated DBPs, THM4, which were comprised primarily of chloroform and bromodichloromethane, were more abundant than HAA5. Numerous unregulated DBPs and a large diversity of unidentified potentially halogenated organic compounds were also produced, with the most abundant being 1,1-dichloroacetone, 1,2-dibromo-3-chloropropane, chloropicrin, dichloroacetonitrile, and trichloracetonitrile. Together, the results demonstrated the DBP formation potential when PHC-contaminated water undergoes chlorination treatment. Further studies are needed to confirm the regulated DBP production and health risks under field relevant conditions.

Bioinspired Structures Made of Silicone Nanofilaments for Upcycling Waste Masks to Reusable N95 Respirators.

The increasing demand for personal protective equipment such as single-use masks has led to large amounts of nondegradable plastic waste, aggravating economic and environmental burdens. This study reports a simple and scalable approach for upcycling waste masks via a chemical vapor deposition technique, realizing a trichome-like biomimetic (TLB) N95 respirator with superhydrophobicity (water contact angle ≥150°), N95-level protection, and reusability. The TLB N95 respirator comprising templated silicone nanofilaments with an average diameter of ∼150 nm offers N95-level protection and breathability comparable to those of commercial N95 respirators. The TLB N95 respirator can still maintain its N95-level protection against particulate matter and viruses after 10 disinfection treatment cycles (i.e., ultraviolet irradiation, microwave irradiation, dry heating, and autoclaving), demonstrating durable reusability. The proposed strategy provides new insight into upcycle waste masks, breaking the existing design and preparation concept of reusable masks.

Pyro-catalysis for refrigerator disinfection via ubiquitous temperature fluctuation

Bacteria breeding in refrigerators can greatly compromise the quality and shelf life of stored food, posing a serious concern. The utilization of disinfection treatments, including ultraviolet irradiation, ozone, and precious metal ions, in refrigerators is constrained by the risk of secondary contamination and the associated high costs. To tackle this matter, we developed a pyro-catalytic disinfection technology that takes advantage of ubiquitous temperature fluctuations to trigger the generation of highly cytotoxic reactive oxygen species for antibacterial. By subjecting the synthesized Ba0.68Sr0.32TiO3 (BST) nanowires or composite patches (BST@C) to temperature fluctuations ranging from 5 to 25 °C for 40 cycles, the survival rates of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were found to be below 5%. More importantly, the survival rates of S. aureus and E. coli were reduced to 19% and 34%, respectively, after only 80 refrigerator opening-closing cycles. This effective demonstration highlights the potential of the safety pyro-catalytic disinfection technology, which does not require additional energy consumption, and exhibits great compatibility with refrigerators.