Disinfectant Agents Research Articles

Chlorine Decay Simulation in Real Water Distribution System Using Epanet Program

Abstract Deterioration of treated drinking water intended for consumption during distribution may be due to physical, chemical or microbiological changes that occur in the water. In addition, the type of pipe material and disintegration of a disinfectant agent can affect the quality of the water supplied. Therefore, the research approach is to simulate the decay residual Cl2 through potable water distribution networks produced by a desalination plant of Oran city in western Algeria. EPANET 2.0 software was used for estimating and predicting Cl2 concentration at different water network points. The value of bulk flow decay coefficient (Kb) is set to −1,99 day−1 for a 50-year-old steel pipe, value for the wall decay coefficient (Kw) was determined using a trial-and-error procedure and assumed to be −1,2 day−1. An efficient model with an extended simulations period of 72 h can plot spatial and temporal variations of residual Cl2 concentrations at all links and nodes. Cl2 is injected at the El Mactaa desalination plant, with a concentration of 0.6 mg/l permanently. As well, it was observed that 51.33% of the Cl2 loss is due to pipe wall reaction, while 42.34 and 6.33% represent the bulk and tank reactions respectively. The results show that the range of residual Cl2 (0.11-0,45 mg/l) and most of the measured values are less than are below the minimum authorized threshold (0.2 – 0.5 mg/l) WHO standard. Therefore, it is recommended to rehabilitate the old water transfer pipes and re-chlorination stations were necessary to add into network. Statistical analysis shows that the calculated results correspond well to the observed data. EPANET can follow the Cl2 concentration in the drinking water network produced by El Mactaa desalination plant. It is a research tool to improve our understanding of water movement in the distribution system.

Biofilm formation and desiccation survival of Listeria monocytogenes with microbiota on mushroom processing surfaces and the effect of cleaning and disinfection

Microbial multispecies communities consisting of background microbiota and Listeria monocytogenes could be established on materials used in food processing environments. The presence, abundance and diversity of the strains within these microbial multispecies communities may be affected by mutual interactions and differences in resistance towards regular cleaning and disinfection (C&D) procedures. Therefore, this study aimed to characterize the growth and diversity of a L. monocytogenes strain cocktail (n = 6) during biofilm formation on polyvinyl chloride (PVC) and stainless steel (SS) without and with the presence of a diverse set of background microbiota (n = 18). L. monocytogenes and background microbiota strains were isolated from mushroom processing environments and experiments were conducted in simulated mushroom processing environmental conditions using mushroom extract as growth medium and ambient temperature (20 °C) as culturing temperature. The L. monocytogenes strains applied during monospecies biofilm incubation formed biofilms on both PVC and SS coupons, and four cycles of C&D treatment were applied with a chlorinated alkaline cleaning agent and a disinfection agent based on peracetic acid and hydrogen peroxide. After each C&D treatment, the coupons were re-incubated for two days during an incubation period for 8 days in total, and C&D resulted in effective removal of biofilms from SS (reduction of 4.5 log CFU/cm2 or less, resulting in counts below detection limit of 1.5 log CFU/cm2 after every C&D treatment), while C&D treatments on biofilms formed on PVC resulted in limited reductions (reductions between 1.2 and 2.4 log CFU/cm2, which equals a reduction of 93.7 % and 99.6 %, respectively). Incubation of the L. monocytogenes strains with the microbiota during multispecies biofilm incubation led to the establishment of L. monocytogenes in the biofilm after 48 h incubation with corresponding high L. monocytogenes strain diversity in the multispecies biofilm on SS and PVC. C&D treatments removed L. monocytogenes from multispecies biofilm communities on SS (reduction of 3.5 log CFU/cm2 or less, resulting in counts below detection limit of 1.5 log CFU/cm2 after every C&D treatment), with varying dominance of microbiota species during different C&D cycles. However, C&D treatments of multispecies biofilm on PVC resulted in lower reductions of L. monocytogenes (between 0.2 and 2.4 log CFU/cm2) compared to single species biofilm, and subsequent regrowth of L. monocytogenes and stable dominance of Enterobacteriaceae and Pseudomonas. In addition, planktonic cultures of L. monocytogenes were deposited and desiccated on dry surfaces without and with the presence of planktonic background microbiota cultures. The observed decline of desiccated cell counts over time was faster on SS compared to PVC. However, the application of C&D resulted in counts below the detection limit of 1.7 log CFU/coupon on both surfaces (reduction of 5.9 log CFU/coupon or less). This study shows that L. monocytogenes is able to form single and multispecies biofilms on PVC with high strain diversity following C&D treatments. This highlights the need to apply more stringent C&D regime treatments for especially PVC and similar surfaces to efficiently remove biofilm cells from food processing surfaces.

Comparative Studies of Changes in Cotton Fabrics and Fibers under the Influence of Disinfection, Sterilization, and DNA Degradation Agents

The purpose of this study was to detect changes in the structure and chemical composition of undyed and dyed cotton fabrics under the influence of six popular agents for disinfection, sterilization, and DNA degradation with different chemical compositions. The original and exposed fabrics and their constituent fibers were subjected to comparative analysis using various optical microscopy methods, infrared spectroscopy, and UV–Vis microspectrophotometry in order to differentiate the exanimated material due to the agents applied. Differences in color, from a slight change to complete discoloration, and in the structure of the tested fabrics, which became more rigid, brittle, or, for example, compact, were noticed. With the use of ATR FTIR, it was possible to identify the presence in the exposed fabrics of residues of these agents that contained quaternary ammonium salts. Bright-field microscopy made it possible to show, above all, changes or lack thereof in the fluorescence properties of single exposed fibers in relation to control ones. With the use of UV–Vis microspectrophotometry, changes in colored fibers following the action of a specific agent on the examined fabrics were monitored. A case study was presented as an application aspect of the research, in which the use of concrete disinfectants was recognized based on changes observed in cotton clothing.

A comprehensive survey and analysis of international drinking water regulations for inorganic chemicals with comparisons to the World Health Organization's drinking-water guidelines.

The World Health Organization (WHO) has published criteria for determining the quality of drinking water since 1958. Since 1984, these criteria were termed "guidelines" to emphasize that they are not national standards, but rather guidelines for nations to develop their own national standards, which may take into account local environmental, social, economic, and cultural conditions. When calculating guideline values (GVs), the WHO reviews the toxicological literature, calculates a health-based value (HBV), and determines whether the HBV should be adopted as a GV. The WHO also considers aesthetic aspects of drinking water quality, such as taste and the staining of plumbing fixtures, and additionally supplies aesthetic values (AVs) for certain drinking water contaminants. There is no central registry for national drinking water standards, so the degree of variation of national drinking water standards is not known. We examined standards, guidelines, and background documents for all inorganic contaminants published by the WHO from 1958-2022. We also searched for national drinking water standards for all independent countries. We found the WHO currently has 16 GVs, six HBVs without GVs, and six AVs without HBVs or GVs for inorganic drinking water contaminants, excluding disinfection agents and their byproducts. More than half of the point of departure studies used to support these values were published in 2005 or earlier. Ninety-eight percent of the world's population lives in jurisdictions with drinking water standards, and 14 countries directly link their national standards to the current WHO's drinking water guidelines. Lack of transparency (standards available only through purchase) and typographical errors are common problems, especially for resource-limited countries. The WHO drinking water guidelines are crucially important for drinking water safety; they are used for guidance or as official standards throughout the world. It is crucial that they be based on the best available science.

Unveiling Fresh-Cut Lettuce Processing in Argentine Industries: Evaluating Salmonella Levels Using Predictive Microbiology Models

A survey was performed to gather information on the processing steps, conditions, and practices employed by industries processing ready-to-eat (RTE) leafy vegetables in Argentina. A total of seven industries participated in the survey. A cluster analysis of the data obtained was performed to identify homogeneous groups among the participating industries. The data collected were used as inputs of two predictive microbiology models to estimate Salmonella concentrations after chlorine washing, during storage and distribution of final products, and to rank the different practices according to the final estimated Salmonella levels. Six different clusters were identified by evaluating the parameters, methods, and controls applied in each processing step, evidencing a great variability among industries. The disinfectant agent applied by all participating industries was sodium hypochlorite, though concentrations and application times differed among industries from 50 to 200 ppm for 30 to 110 s. Simulations using predictive models indicated that the reductions in Salmonella in RTE leafy vegetables would vary in the range of 1.70–2.95 log CFU/g during chlorine-washing depending on chlorine concentrations applied, washing times, and vegetable cutting size, which varied from 9 to 16 cm2 among industries. Moreover, Salmonella would be able to grow in RTE leafy vegetables during storage and distribution, achieving levels of up to 2 log CFU/g, considering the storage and transportation temperatures and times reported by the industries, which vary from 4 to 14 °C and from 18 to 30 h. These results could be used to prioritize risk-based sampling programs by Food Official Control or determine more adequate process parameters to mitigate Salmonella in RTE leafy vegetables. Additionally, the information gathered in this study is useful for microbiological risk assessments.

Novel Antibacterial and Biocompatible Nanostructured Gels Based on One-step Synthesis as a Potential Disinfectant for Endodontic Infection Control

AimThe objective of this study was to develop nanostructured gels as biocompatible intracanal disinfectants by one-step microwave radiation-assisted synthesis. MethodsPolyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) were used as a support network, and polyethylene glycol (PEG) was used as a reducing agent. The gels were characterized by measuring the swelling ratio (SR) and rheological properties and by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The antibacterial effects of each gel were evaluated against the endodontic clinical strain Enterococcus faecalis. Then, the viability of the 21-day mature multispecies bacterial biofilm was assessed using confocal microscopy in an ex vivo model, where the biofilm was exposed to the mix of nanogels. The cell proliferation, viability, and morphology of human periodontal ligament (HPDL) cells were quantified using a real-time IncuCyte® S3 Live-Cell System. Viability was measured by confocal microscopy using an ex vivo model exposing a 21-day mature multispecies bacterial biofilm to the mix of nanogels. ResultsThe antibacterial activity of the gels coincided with the superficial characterization and the solubility of the gel in the growth medium. Gels with higher viscosity (327.85-980.58 Pa s), higher dissolution (42-70%SR), and lower porosity (no porosity and 611.63 nm) showed excellent antibacterial activity against E. faecalis. Despite their physicochemical characteristics, CuNPs gels showed greater effectiveness against E. faecalis.These nanostructured gels with high PVA concentrations promote HPDL cells proliferation while still exerting antibacterial properties. Mix of nanogels showed an increase non-viable cells biomass from at of application. ConclusionsThe use of biocompatible polymers influences the physicochemical, bactericidal, and cytotoxic response, making these materials potential disinfectant agents against resistant bacteria with good biocompatibility and improved HPDL cells proliferation.

In the View of Electrons Transfer and Energy Conversion: The Antimicrobial Activity and Cytotoxicity of Metal-Based Nanomaterials and Their Applications.

The global pandemic and excessive use of antibiotics have raised concerns about environmental health, and efforts are being made to develop alternative bactericidal agents for disinfection. Metal-based nanomaterials and their derivatives have emerged as promising candidates for antibacterial agents due to their broad-spectrum antibacterial activity, environmental friendliness, and excellent biocompatibility. However, the reported antibacterial mechanisms of these materials are complex and lack a comprehensive understanding from a coherent perspective. To address this issue, a new perspective is proposed in this review to demonstrate the toxic mechanisms and antibacterial activities of metal-based nanomaterials in terms of energy conversion and electron transfer. First, the antimicrobial mechanisms of different metal-based nanomaterials are discussed, and advanced research progresses are summarized. Then, the biological intelligence applications of these materials, such as biomedical implants, stimuli-responsive electronic devices, and biological monitoring, are concluded based on trappable electrical signals from electron transfer. Finally, current improvement strategies, future challenges, and possible resolutions are outlined to provide new insights into understanding the antimicrobial behaviors of metal-based materials and offer valuable inspiration and instructional suggestions for building future intelligent environmental health.

Coefficient Test of Antimicrobial Phenol Combination of Eichhornia crassipes and Pistia stratiotes Extract In Vitro as Alternative Disinfection Candidates

Eichhornia crassipes and Pistia stratiotes are weeds that often pollute water areas. These two contain various active compounds that act as antimicrobials, which have the potential as disinfection agents to prevent the transmission of pathogenic bacteria and fungi. An antimicrobial substance is said to be effective as a good disinfectant if it has a phenol coefficient value equal to or more than the 5% phenol comparison substance. The aim of this research was to test the effectiveness of a combination of Eichhornia crassipes and Pistia stratiotes extracts as a disinfection candidate through the phenol coefficient test. This in vitro experimental study was carried out using a dilution technique. The combination treatment of Eichhornia crassipes and Pistia stratiotes extracts and 5% phenol was tested against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and also Candida albicans yeast. Observations on the test media suspension tubes that were clear or did not show the growth of the test microbes for a period of 5, 10, and 15 minutes. The phenol coefficient value of the combination treatment of Eichhornia crassipes and Pistia stratiotes extracts was ≥1 with 5% phenol as comparison. Higher coefficient values were obtained for Staphylococcus aureus, equivalent values of 5% phenol were found for E.coli, P.aeruginosa, and C.albicans; whereas in S.typhi the value is <1. The combination treatment of E.crassipes and P.stratiotes extracts resulted in a phenol coefficient value equivalent to that of 5% phenol comparator, for several tested bacteria and yeasts. So it has effectiveness as a preparation for disinfection. The combination of Eichhornia crassipes and Pistia stratiotes extracts has antimicrobial effectiveness and can be developed as an alternative disinfection candidate.

Стратегия развития института дезинфектологии на современном этапе

Today, the Disinfectology Institute within the Federal Scientific Center of Hygiene named after F.F. Erisman of Rospotrebnadzor is taking on new forms, combining innovative development and preserving established traditions. Emphasizing the scientific direction of activity, great attention is paid to solving problems in the practical sphere, expert and educational areas. Updated research work, intra- and inter-sectoral interaction between scientific and practical institutions, formation of operational tools in the conditions of licensing of disinfection, disinsection and deratization services allow to implement at the modern level and maintain the status of scientific and methodological center in the field of disinfectology in the Russian Federation and in the post-Soviet territory. Keywords: development strategy, research work, practical aid, expertise of disinfection agents, экспертиза дезинфекционных средств, licensing of disinfection, disinsection, and deratization services, educational activities

Implication of Sodium Hypochlorite as a Sanitizer in Ready-to-Eat Salad Processing and Advantages of the Use of Alternative Rapid Bacterial Detection Methods.

The use of disinfection agents in the washing processing of ready-to-eat (RTE) vegetables, especially sodium hypochlorite, is a common industrial practice performed to enhance microbiological quality. However, some studies have reported a restart of bacterial growth and a substantial increase in bacterial load during early storage associated with the use of disinfection agents, which might represent a risk for consumers. We evaluated the effect of sodium hypochlorite on bacterial growth trends during the shelf-life in Lactuca sativa, simulating the industrial procedures for RTE vegetable packaging. Immediately after sodium hypochlorite treatment, an effective abatement of the bacterial load was observed, followed by a restart of growth throughout storage. After 5 days, the bacterial load was close to that reached by the control samples, indicating that the net increase in bacterial load was significantly higher in the treated samples. This might be ascribed to the reduction in competitive microflora and/or to the induction of adaptive responses by resting bacteria, which might select disinfectant-resistant bacteria. These findings elicit some concerns about the actual duration of the shelf-life; products might decrease their microbiological quality earlier during storage, pointing out the need to better clarify the impact of sodium hypochlorite as a sanitizer to closer consider its use in RTE vegetable processing. Furthermore, due to the importance of the rapid estimation of bacterial load and the early detection of foodborne pathogens throughout the food chain, the accuracy of the rapid bacteria detection method, the Micro Biological Survey (MBS), and its effectiveness for microbiological analyses of RTE vegetables were evaluated.

Effectiveness of a combined UV-C and ozone treatment in reducing healthcare-associated infections in hospital facilities

Hospital-acquired infections pose an ongoing threat to patient safety due to the presence of multi-drug-resistant organisms (MDROs) and other pathogens such as Clostridioides difficile which are dependent on thorough and effective cleaning and disinfection by personnel. This study evaluated the influence of UV-C air treatment: the air in the room was sanitized by UV-C and redirected into the room. In addition, ozone was released into the room to treat actual surfaces in low-risk areas such as hospital gyms, and high- to medium-risk areas such as hospital rooms. To this aim, a portable device designed for treating the environment air was tested against nine bacterial strains including Aspergillus spp. and Clostridioides spp. The use of UV-C air treatment during daily operations and ozone treatment achieved at least a 2-log10 pathogen reduction except for Clostridioides spp. Effective prevention of C.difficile normally requires the use of combined approaches that include chemical compounds and disinfection agents whose toxicity can be harmful not only to patients but also to healthcare personnel. Thus, the proposed no-touch device may be evaluated in future research to assess the needed requirements for its possible and full implementation in hospitals.

Coupling ozone with microbubbles (OMB) water for food disinfection: Effects on microbiological safety, physicochemical quality, and reducing pink discoloration of jumbo squid (Dosidicus gigas)

Jumbo squid (Dosidicus gigas) is one of the most important squid species worldwide. However, it is highly perishable due to microbial spoilage. Here, we demonstrated a soaking treatment using ozone-microbubble (OMB) water as an alternative disinfection platform for squid decontamination prior to refrigerated storage. Compared with the control treatment (soaking squids with reverse osmosis water for 5 min [RO5]), soaking squids with OMB for 3 min (OMB3) was revealed to optimally reducing the growth of microbiological contaminants (e.g., TPC and coliform) and maintaining the squid qualities (e.g., TVBN, ammonia, and color). Unlike RO5-treated squids, the microstructure of OMB3-treated squids was intact and uniform in size, which is similar to the general structure of the raw ones'. OMB3 also retarded the pink discoloration caused by pigments released from squid chromatophores. Moreover, OMB3 was able to delay the chromatophore damage in squid skin, consequently retarding pigment release and color change throughout storage periods. Overall, this study demonstrated the effectiveness of OMB as a potential disinfection agent and preventative measure for squids without severely affecting their qualities.

Prevention of internal bacterial colonization of dental implants: A comparative longitudinal observational study.

Previous studies have indicated a progressive internal bacterial colonization of implants and possible implications for peri-implant bone loss. The aim of this study was to evaluate a decontamination protocol, two disinfectants, and a sealant for their ability to prevent such a colonization. Bacterial samples were harvested from the peri-implant sulcus (external) and following abutment removal from the implant cavity (internal) during routine supportive peri-implant care in 30 edentulous patients 2 years after they had obtained two implants. In a split-mouth design, implants were randomly assigned to receive either internal decontamination alone (10% H2 O2 , brush) or additional placement of either sealant (GS), disinfectant agent (CHX-varnish) or disinfectant gel (1% CHX-gel), in the internal cavity before remounting of abutment/suprastructure. Twelve months later, internal and external sampling was repeated. Total bacterial counts (TBCs) were determined using real-time PCR in a total of 240 samples (eight per patient). Total bacterial counts in the internal cavity significantly reduced overall treatment modalities 1 year after the treatments (4.0 [2.3-6.9]-fold reduction; p = .000). No significant differences between the four treatment types were found (p = .348). Comparison of internal and external sampling points revealed significant correlation (R2 = .366; p = .000) with systematically higher TBC counts in external samples. Within the limitations of the present study, it can be concluded that the use of disinfectant agents or a sealant did not show an additional benefit in the prevention of internal bacterial colonization of implants compared to a decontamination protocol alone.

Comparative Bioactivity Study of some Organotin (IV) 2-Chlorobenzoate compounds as Disinfectant agent

This research was carried out to study the bioactivitytest as disinfectant of two derivatives of organotin(IV) carboxylate compounds; diphenyltin(IV) di-2-chlorobenzoate (DPT2-CBz) (2) and triphenyltin(IV) 2-chlorobenzoate (TPT2-CBz) (4), against two pathogenic bacteria. Compounds 2 and 3 were successfully prepared by reactingdiphenyltin(IV) oxide (DPTO) (1) and triphenyltin(IV) hydroxide (TPTOH) (3) with 2-chlorobenzoic acid(2-HCBz)with yieldsof 87.71% and 88.73%, respectively. The characterization of the synthesized compounds was performed with several spectroscopy techniques such as UV, IR, 1HNMR, 13CNMR, and microelemental analyzer. The optical density (OD) test for both compounds measured using UV-Vis at 600 nm showeda goodbioactivity against two bacteria, Gram-negative Salmonella sp. and Gram-positive Staphylococcus aureus. The data revealed that compound 4 has bigger bioactivity than compound 2 and the positive control ofcommercial disinfectant (2.5% pine oil). The bioactivity of compound 4was optimum at concentration of 5x10-4 M and contact timeof 15 minutes.These data corresponding to the decrease of absorbance from 0.6640 to 0.0955 for Salmonella sp., and 0.6565 to 0.1295 for S. aureus, whereas although compound 2reached the optimum activityat the same concentration and contact time with compound 4, but the decrease of absorbance was less namely 0.6640 to 0.1305 for Salmonella sp., and 0.6565 to 0.196 for S. aureus. The decrease of absorbance in the measurement of OD implies that both compounds are potential to be used as disinfectant agent.

Complex drug kenocox against <i>Eimeria</i> spp. oocysts in turkeys

The purpose of the researchis to test the efficacy of different concentrations of composite Kenocox againstEimeriaspp. oocysts in turkeys in a laboratory experiment and under production conditions.Materials and methods. The anti-Eimeria activity of the new composite disinfection agent Kenocox was tested as compared with phenol in two stages. The first laboratory stage used 2, 4 and 6% Kenocox and 4% phenol as the base drug. The second stage used a bioassay with artificial infection of the young turkeys, and a production test was conducted on a poultry farm.Results and discussion. The conducted studies showed 92.96% intense-effectiveness of 2% Kenocox. 4 and 6% Kenocox showed 100% efficacy against sporulatedEimeriaspp. oocysts, and the base 4 % phenol provided 74.98% efficacy. During the production test of 4% Kenocox on the turkey farm, 91.7% intense-effectiveness was detected.

Eco-friendly and effective antimicrobial Melaleuca alternifolia essential oil Pickering emulsions stabilized with cellulose nanofibrils against bacteria and SARS-CoV-2

Melaleuca alternifolia essential oil (MaEO) is a green antimicrobial agent suitable for confection eco-friendly disinfectants to substitute conventional chemical disinfectants commonly formulated with toxic substances that cause dangerous environmental impacts. In this contribution, MaEO-in-water Pickering emulsions were successfully stabilized with cellulose nanofibrils (CNFs) by a simple mixing procedure. MaEO and the emulsions presented antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Moreover, MaEO deactivated the SARS-CoV-2 virions immediately. FT-Raman and FTIR spectroscopies indicate that the CNF stabilizes the MaEO droplets in water by the dipole-induced-dipole interactions and hydrogen bonds. The factorial design of experiments (DoE) indicates that CNF content and mixing time have significant effects on preventing the MaEO droplets' coalescence during 30-day shelf life. The bacteria inhibition zone assays show that the most stable emulsions showed antimicrobial activity comparable to commercial disinfectant agents such as hypochlorite. The MaEO/water stabilized-CNF emulsion is a promissory natural disinfectant with antibacterial activity against these bacteria strains, including the capability to damage the spike proteins at the SARS-CoV-2 particle surface after 15 min of direct contact when the MaEO concentration is 30 % v/v.

P101: Feasibility Study of the Percutaneous Access Device for Long-Term LVAS Application

Background: Driveline infection (DLI) is a major chronic adverse event requiring re-hospitalization after durable left ventricular assist system (LVAS) implantation. The risk of DLI continues to rise over time and is associated with long-term mortality. Percutaneous access device (PAD) may be a potential technology to prevent DLI by the mechanical barrier interfaced with epidermal tissue. Methods: A prototype PAD was fabricated for the LVAS driveline and evaluated with two mini pigs for up to 69 days at the GLP facility. Test articles were implanted at the subcutaneous position on the left and right abdominal walls. After implant surgery, antibiotics were administered intravenously for three days for prophylactic purposes and discontinued unless there was any sign of infection. Skin and implanted PAD are showered weekly with warm water without any other disinfectant agent. Animals received humane care without restraints in the cage and were checked for general physical condition daily. The blood sample was collected at baseline, POD 7, 14, 28, and 69. Test Animals were euthanized, and articles and surrounding tissue samples were explanted en bloc for histopathology assessment. Results: Postoperative recovery was uneventful, and no remarkable organ dysfunction and no sign of infection were identified. A normal inflammatory response was observed on the skin a few days post-op but normalized within a week. Good tissue integrity was confirmed (no visible gap) around the interface between the test article and the skin without evidence of epidermal down growth and infection. Rich fibromatous tissue with keratin formation was confirmed. Conclusion: Initial feasibility of PAD for LVAS driveline was verified. Further design optimization will be required to finalize the clinical prototype before the pre-clinical GLP study.Figure 1. Upper left: Percutaneous access device tested (implanted to the test animal) Upper right: Close-up view of the skin interface Lower center: Histopathology of test article at subcutaneous tissue

Exposure dose and temperature of chlorine on deterioration of thin-film composite membranes for reverse osmosis and nanofiltration

In this study, the effect of chlorine, which is used as a chemical cleaning agent or disinfection agent on membrane deterioration, was analyzed under various conditions during the membrane process. Reverse osmosis (RO: ESPA2-LD and RE4040-BE) and nanofiltration (NF: NE4040-70) membranes made of polyamide (PA) thin film composite (TFC) were used for evaluation. Chlorine exposure was performed at doses ranging from 1000 ppm h to 10,000 ppm h using 10 ppm and 100 ppm, and temperatures from 10 °C to 30 °C. Raw water containing NaCl, MgSO4, and dextrose was used to compare the filtration performance after exposure to each of the conditions studied. Reduction in removal performance and enhancement in permeability were observed as chlorine exposure increased. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscope (SEM) were employed to determine the surface characteristics of the decomposed membranes. ATR-FTIR was used to compare the intensity of the peaks related to the TFC membrane. Based on the analysis, the state of membrane degradation was elucidated. SEM was used to confirm visual degradation of the membrane surface. Permeability and correlation analyses were performed on CnT as an index for determining membrane lifetime in order to investigate the power coefficient. The relative influence of the exposure concentration and time on membrane degradation was explored by comparing the power efficiency according to the exposure dose and temperature.

Synergistic effects of Bi2O3 and Ta2O5 for efficient electrochemical production of H2O2

Electrochemical oxygen reduction reaction (ORR) through a two-electron pathway has been provided a green route for on-site hydrogen peroxide (H2O2) production. Developing high-selective electrocatalysts for H2O2 production are urgently sought. Herein, a m-Bi2O3/Ta2O5 electrocatalyst (m: “Bi” mass contents) has been successfully synthesized by simple physical mixing associated with an outstanding selectivity towards H2O2 (94.7%), over 10% higher than Ta2O5 (80.9%) and Bi2O3 (81.7%). 10-Bi2O3/Ta2O5 also exhibits 471 mmol/(gcat·h) H2O2 yield with 91.8% Faraday Efficiency. The in-situ generated H2O2 can function as disinfection agent for efficiently deactivating model bacteria (e.g., Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli) within 30 min. In-situ Raman and DFT proposed the synergistic effects of Bi2O3 and Ta2O5 in boosting 2e- ORR performance. In this work, it not only presents a high-selective electrocatalyst for 2e- ORR, but also provides a new idea for electrocatalyst design from the perspective of reaction process.

Enhancing gallic acid antimicrobial activity against Escherichia coli by ultraviolet-C light irradiation

This study aimed to evaluate the UV-C light effect on enhancing the antimicrobial activity of gallic acid (GA) against Escherichia coli at different initial microbial loads. The highest microbial reduction (3.08 ± 0.09 log) was attained at low microbial load after 10-min contact with irradiated GA (IGA). Increasing the initial microbial load (6–7 × 107 CFU/mL) reduces the IGA effect. Application of the IGA (0.015 M) in combination with UV-C light (15 min) caused lethal injury in E. coli at a low microbial load. Furthermore, at a low microbial load, a contact time of 5 min and 0.15 M was enough to reach >5-log reductions, whereas, at high microbial concentrations, the maximum GA concentration (0.25 M) was necessary to achieve the same inactivation. Increasing GA concentration, irreversible microbial damage was observed, with no microbial growth in samples treated for 10 min with IGA at 0.10–0.25 stored at 22 °C. Industrial relevanceGA is a phenolic compound with limited antimicrobial activity. However, the UV-C light treatment enhances its antimicrobial activity, increasing its application as a disinfectant of surfaces, instruments, and fresh food products, among other applications currently demanded by the consumers and food industry. In this sense, IGA can be used as a disinfectant agent for fruit and vegetables, in combination with novel or traditional technologies as a combined methodology to reduce the microbial load, or even as a preservative to maintain the microbial load during storage.