Ferrate (Fe(VI): HFeO4- /FeO42-), a potent oxidant, has been investigated as an alternative chemical disinfectant in water treatment due to its reduced production of disinfection by-products. In this study, we assessed the disinfecting ability of potassium ferrate against a variety of microorganisms, including waterborne pathogens, under varying pH and water temperature conditions. We presented CT values, a metric of ferrate concentrations (C) and contact time (T), to quantify microbial inactivation rates. Among the tested microorganisms, human adenovirus was the least resistant to ferrate, followed by waterborne bacteria such as Escherichia coli and Vibrio cholerae, and finally, the protozoan parasite Giardia duodenalis. We further investigated the impact of two pH values (7 and 8) and two temperatures (5 and 25 °C) on microbial inactivation rates, observing that inactivation rates increased with lower pH and higher temperature. In addition to showcasing ferrate\'s capacity to effectively inactivate a range of the tested microorganisms, we offer a ferrate CT table to facilitate the comparison of the effectiveness of various disinfection methods.

BACKGROUND: The World Health Organization recommended the use of chemical-based disinfectants as an effective prevention of the COVID-19 pandemic. However, calls for poisoning were reported in several medical centers. The widespread use of chemical-based disinfectants as a preventive measure during the COVID-19 pandemic has underscored potential gaps in community awareness and performance, posing health risks. This study evaluates and compares levels of awareness and performance regarding the safe use of disinfectants in Jordan and UAE.
METHODS: The study was conducted between October 2022 and June 2023 via an online questionnaire. Data of respondents from Jordan (n = 828) and UAE (n = 619) were analyzed using SPSS. ANOVA, Mann-Whitney, and Kruskal-Wallis tests evaluated significant differences in awareness and performance levels across different demographic groups in Jordan/UAE and between them. Spearman\'s correlation test examined the correlation between awareness and performance among respondents. Multinomial logistic regression analysis explored associations between various variables and awareness/performance levels within each population.
RESULTS: Findings reveal weak awareness (72.4% and 9.03% in UAE and Jordan, respectively) and moderate performance level (98.8% in UAE and Jordan), with a weak correlation (UAE, rho = 0.093; Jordan, rho = 0.164) observed between the two countries (P < 0.05). Multinomial logistic regression analysis indicates gender-related associations with awareness levels and education-related associations with performance levels.
CONCLUSIONS: The study emphasizes the urgent need for awareness campaigns and workshops to promote safer disinfectant practices to develop effective interventions aligning with sustainable development goals.

BACKGROUND: Ensuring the safety of dental unit waterlines (DUWLs) has become a pivotal issue in dental care practices, focusing on the health implications for both patients and healthcare providers. The inherent structure and usage conditions of DUWLs contribute to the risk of biofilm formation and bacterial growth, highlighting the need for effective disinfection solutions.The quest for a disinfection method that is both safe for clinical use and effective against pathogens such as Staphylococcus aureus and Escherichia coli in DUWLs underscores the urgency of this research.
METHODS: Chlorine dioxide disinfectants at concentrations of 5, 20, and 80 mg/L were used to treat biofilms of S. aureus and E. coli cultured in DUWLs. The disinfection effectiveness was assessed through bacterial counts and culturing. Simultaneously, human skin fibroblast cells were treated with the disinfectant to observe changes in cell morphology and cytotoxicity. Additionally, the study included corrosion tests on various metals (carbon steel, brass, stainless steel, aluminum, etc.).
RESULTS: Experimental results showed that chlorine dioxide disinfectants at concentrations of 20 mg/L and 80 mg/L significantly reduced the bacterial count of S. aureus and E. coli, indicating effective disinfection. In terms of cytotoxicity, higher concentrations were more harmful to cellular safety, but even at 80 mg/L, the cytotoxicity of chlorine dioxide remained within controllable limits. Corrosion tests revealed that chlorine dioxide disinfectants had a certain corrosive effect on carbon steel and brass, and the degree of corrosion increased with the concentration of the disinfectant.
CONCLUSIONS: After thorough research, we recommend using chlorine dioxide disinfectant at a concentration of 20 mg/L for significantly reducing bacterial biofilms in dental unit waterlines (DUWLs). This concentration also ensures satisfactory cell safety and metal corrosion resistance.

So far, about 130 disinfection by-products (DBPs) and several DBPs-groups have had their potential endocrine-disrupting effects tested on some endocrine endpoints. However, it is still not clear which specific DBPs, DBPs-groups/subgroups may be the most toxic substances or groups/subgroups for any given endocrine endpoint. In this study, we attempt to address this issue. First, a list of relevant DBPs was updated, and 1187 DBPs belonging to 4 main-groups (aliphatic, aromatic, alicyclic, heterocyclic) and 84 subgroups were described. Then, the high-priority endocrine endpoints, DBPs-groups/subgroups, and specific DBPs were determined from 18 endpoints, 4 main-groups, 84 subgroups, and 1187 specific DBPs by a virtual-screening method. The results demonstrate that most of DBPs could not disturb the endocrine endpoints in question because the proportion of active compounds associated with the endocrine endpoints ranged from 0 (human thyroid receptor beta) to 32% (human transthyretin (hTTR)). All the endpoints with a proportion of active compounds greater than 10% belonged to the thyroid system, highlighting that the potential disrupting effects of DBPs on the thyroid system should be given more attention. The aromatic and alicyclic DBPs may have higher priority than that of aliphatic and heterocyclic DBPs by considering the activity rate and potential for disrupting effects. There were 2 (halophenols and estrogen DBPs), 12, and 24 subgroups that belonged to high, moderate, and low priority classes, respectively. For individual DBPs, there were 23 (2%), 193 (16%), and 971 (82%) DBPs belonging to the high, moderate, and low priority groups, respectively. Lastly, the hTTR binding affinity of 4 DBPs was determined by an in vitro assay and all the tested DBPs exhibited dose-dependent binding potency with hTTR, which was consistent with the predicted result. Thus, more efforts should be performed to reveal the potential endocrine disruption of those high research-priority main-groups, subgroups, and individual DBPs.

Disinfection by-products (DBPs) are prevalent contaminants in drinking water and are primarily linked to issues regarding water quality. These contaminants have been associated with various adverse health effects. Among different treatment processes, nanofiltration (NF) has demonstrated superior performance in effectively reducing the levels of DBPs compared to conventional processes and ozone-biological activated carbon (O3-BAC) processes. In this experiment, we systematically investigated the performance of three advanced membrane filtration treatment schemes, namely \"sand filter + nanofiltration\" (SF + NF), \"sand filter + ozone-biological activated carbon + nanofiltration\" (SF + O3-BAC + NF), and \"ultrafiltration + nanofiltration\" (UF + NF), in terms of their ability to control disinfection by-product (DBP) formation in treated water, analyzed the source and fate of DBP precursors during chlorination, and elucidated the role of precursor molecular weight distribution during membrane filtration in relation to DBP formation potential (DBPFP). The results indicated that each treatment process reduced DBPFP, as measured by trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP), with the SF + O3-BAC + NF process being the most effective (14.27 μg/L and 14.88 μg/L), followed by the SF + NF process (21.04 μg/L and 16.29 μg/L) and the UF + NF process (26.26 μg/L and 21.75 μg/L). Tyrosine, tryptophan, and soluble microbial products were identified as the major DBP precursors during chlorination, with their fluorescence intensity decreasing gradually as water treatment progressed. Additionally, while large molecular weight organics (60-100,000 KDa) played a minor role in DBPFP, small molecular weight organics (0.2-5 KDa) were highlighted as key contributors to DBPFP, and medium molecular weight organics (5-60 KDa) could adhere to the membrane surface and reduce DBPFP. Based on these findings, the combined NF process can be reasonably selected for controlling DBP formation, with potential long-term benefits for human health.

BACKGROUND: Smartphones in medical settings pose infection risks due to harbouring pathogenic bacteria.
OBJECTIVE: This pilot study assessed the effectiveness duration of sanitization methods, focusing on 70% isopropyl alcohol wipes and ultraviolet-C (UVC) boxes, aiming to obtain preliminary data on the reduction in total bacterial load 3 h post-sanitization.
METHODS: A randomized monocentric trial with two intervention arms (wipes and UVC boxes) was designed. As participants, healthcare workers from three wards at Fondazione Policlinico Universitario \'A. Gemelli\' IRCCS Hospital were recruited, stratified by ward, and block randomized within each ward to control confounders.
RESULTS: Seventy-one healthcare workers, mostly nurses (62%) were included in the study. Initial bacterial load reduction was significant with both disinfection techniques, but after 3 h both methods showed increased bacterial levels, with wipes displaying potentially higher residual efficacy (P=0.056). To adequately size a trial (89% power, significance level 0.05) for assessing the residual efficacy of alcohol-impregnated wipes compared with UVC boxes at 3 h post-sanitization, 503 professionals per group were required.
CONCLUSIONS: This study highlights the necessity for guidelines on hospital smartphone sanitization and educational initiatives for healthcare workers and patients. Further studies, adequately sized, are necessary to determine optimal sanitization intervals and assess pathogen transmission risks.

In this study, we investigated the effects of various disinfectants used to prevent infectious diseases on medical images and medical equipment. First, we investigated the effect of residual disinfectant on medical images in CT, mammography (MMG), and general imaging systems. Acrylic discs with various disinfectants attached were photographed using each imaging device, and visual evaluation and changes in image signal values were evaluated. We also conducted a questionnaire survey of each manufacturer regarding cleaning methods for medical devices. With CT/MMG, residual disinfectant could be visually confirmed on the image. Although this could not be confirmed with the general imaging system, a significant difference was confirmed in the image signal values of the general imaging system through statistical analysis. This is thought to be largely due to the influence of nonlinearity in the short-time imaging range of general imaging equipment. In addition, from the responses to a questionnaire survey of each medical device manufacturer, we were able to understand detailed cleaning methods that are not covered in medical device instruction manuals.

BACKGROUND: Various methods, chemical and physical, disinfect dental impressions. Common chemicals include 1% Sodium Hypochlorite and 2% glutaraldehyde, while UV radiation is a prevalent physical method. Few studies compare their effects on dimensional stability in polyether impressions. This study aims to assess such stability using different disinfection methods. Therefore, this study was planned to evaluate the dimensional stability of polyether impression material using different disinfection methods.
METHODS: This in vitro study compared the effects of chemical disinfectants (1% Sodium Hypochlorite and 2% glutaraldehyde) and UV irradiation on the dimensional stability of polyether impression material. Groups A, B, C, and D, each with ten samples (N = 10), were studied. Group A was untreated (control). Group B was treated with 2% glutaraldehyde for 20 min, Group C with 1% Sodium Hypochlorite for 20 min, and Group D with UV rays for 20 min. A pilot milling machine drill was used to make four parallel holes labeled A, B, C, and D in the anterior and premolar regions from right to left. After sequential drilling, four implant analogs were positioned using a surveyor for accuracy. Ten open-tray polyether impressions were made and treated as described in the groups, followed by pouring the corresponding casts. Distortion values for each disinfection method were measured using a coordinate measuring machine capable of recording on the X- and Y-axes.
RESULTS: A comprehensive analysis was conducted using the one-way ANOVA test for distinct groups labeled A, B, C, and D, revealing significant differences in the mean distances for X1, X2, X4, X5, and X6 among the groups, with p-values ranging from 0.001 to 0.000. However, no significant differences were observed in X3. Notably, mean distances for the Y variables exhibited substantial differences among the groups, emphasizing parameter variations, with p-values ranging from 0.000 to 0.033. The results compared the four groups using the one-way ANOVA test, revealing statistically significant distance differences for most X and Y variables, except for X3 and Y4. Similarly, post-hoc Tukey\'s tests provided specific pairwise comparisons, underlining the distinctions between group C and the others in the mean and deviation distances for various variables on both the X- and Y-axes.
CONCLUSIONS: This study found that disinfection with 1% sodium hypochlorite or UV rays for 20 min maintained dimensional stability in polyether impressions.

BACKGROUND: Disinfection byproducts (DBPs) have been shown to impair thyroid function in experimental models. However, epidemiological evidence is scarce.
METHODS: This study included 1190 women undergoing assisted reproductive technology (ART) treatment from the Tongji Reproductive and Environmental (TREE) cohort from December 2018 to August 2021. Serum thyrotropin (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were measured as indicators of thyroid function. FT4/FT3 and TSH/FT4 ratios were calculated as markers of thyroid hormone homeostasis. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two most abundant HAAs, in urine were detected to assess individual DBP exposures.
RESULTS: After adjusting for relevant covariates, positive associations were observed between urinary TCAA concentrations and serum TSH and TSH/FT4 levels (e.g., percent change = 5.82 %, 95 % CI: 0.70 %, 11.21 % for TSH), whereas inverse associations were found for serum FT3 and FT4 (e.g., percent change = -1.29 %, 95 % CI: -2.49 %, -0.07 % for FT3). There also was a negative association between urinary DCAA concentration and serum FT4/FT3 (percent change = -2.49 %, 95 % CI: -4.71 %, -0.23 %). These associations were further confirmed in the restricted cubic spline and generalized additive models with linear or U-shaped dose-response relationships.
CONCLUSIONS: Urinary HAAs were associated with altered thyroid hormone homeostasis among women undergoing ART treatment.

BACKGROUND: During the COVID-19 pandemic, increased hand hygiene practices were implemented. Impaired skin health on the hands among healthcare workers has been reported previously. Knowledge of how worker in other occupations have been affected is scarce.
OBJECTIVE: To investigate self-reported hand water-, and soap exposure and use of hand disinfectants, and hand eczema (HE) in frontline workers outside the hospital setting and in IT personnel during the COVID-19 pandemic.
METHODS: In this cross-sectional study, a questionnaire was sent out between 1 March and 30 April in 2021, to 6060 randomly selected individuals representing six occupational groups.
RESULTS: A significant increase in water exposure and hand disinfectant use was shown: Relative position (RP) 19; 95% confidence interval (CI) 0.17-0.21 and RP = 0.38: 95% CI 0.36-0.41, respectively. Newly debuted HE was reported by 7.4% of the population, more frequently among frontline workers (8.6%) compared to IT personnel (4.9%).
CONCLUSIONS: Water and soap exposure and use of hand disinfectants increased during COVID-19 pandemic, which may increase the risk of hand eczema. This highlights the importance of communication and implementation of preventive measures to protect the skin barrier also in occupations other than healthcare workers.