Search Results (232)

Background: Airborne transmission of bacteria, viruses, and fungal spores poses a major threat in enclosed settings, particularly nursing homes where residents are highly vulnerable. Compressive Heating Air Sterilization Technology (CHAST) applies compressive heating to inactivate microorganisms without reliance on filtration or chemicals. Methods: CHAST efficacy was evaluated in laboratory and deployed for a feasibility and performance validation study of air sterilization in a nursing home environment. Laboratory studies tested prototypes (300–5000 CFM; 220–247 °C) against aerosolized surrogates including Bacillus globigii (Bg), B. stearothermophilus (Bst), B. thuringiensis (Bt), Escherichia coli, and MS2 bacteriophage. Viral inactivation thresholds were further assessed by exposing MS2 to progressively lower treatment temperatures (64.5–143 °C). Feasibility and performance validation evaluation involved continuous operation of two CHAST units in a nursing home, with pre- and post-treatment air samples analyzed for bacterial and fungal burden. Results: Laboratory testing demonstrated consistent microbial inactivation, with most prototypes achieving > 6-log (99.9999%) reductions across bacterial spores, vegetative bacteria, and viruses. A 5000 CFM prototype achieved > 7-log (99.99999%) elimination of B. globigii. MS2 was completely inactivated at 240 °C, with modeling suggesting a threshold for total viral elimination near 170 °C. In the feasibility study, baseline sampling revealed bacterial (35 CFU/m³) and fungal (17 CFU/m³) contamination, dominated by Bacillus, Staphylococcus, Cladosporium, and Penicillium. After 72 h of CHAST operation, discharge air contained no detectable viable organisms, and fungal spore counts showed a 93% reduction relative to baseline return air. Units maintained stable operation (464 °F ± 2 °F; 329–335 CFM) throughout deployment. Conclusion: CHAST reproducibly and scalably inactivated airborne bacteria, viruses, and fungi under laboratory and feasibility field studies, supporting its potential as a chemical-free strategy to improve infection control and indoor air quality in healthcare facilities. Full article

Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) are E. coli pathovars of particular relevance to infant health. While the intestinal tract of humans and animals constitutes their primary habitat, these bacteria can also persist in natural environments such as sand. The aim of this study was to evaluate the persistence of STEC and EPEC strains in sand microcosms under controlled conditions of heat and desiccation in order to estimate their viability in this matrix and provide evidence regarding the potential risks associated with the use of sandboxes in public spaces. The study included STEC strains belonging to clinically important serotypes (O26:H11, O103:H2, O111:H8, O121:H19, O145:NM, O157:H7 and O174:H28), animal-derived EPEC strains, and a non-pathogenic E. coli strain (NCTC 12900). The strains were inoculated into sterile sand microcosms and maintained at 37 °C. Death curves, persistence in the matrix, presence of virulence genes, and ability to produce biofilm were evaluated. The death and persistence curves varied by serotype; some strains remained viable in the viable but non-culturable state for extended periods. All strains retained their virulence-associated genetic markers throughout the assays. None of the STEC strains was classified as a biofilm producer under the experimental conditions, whereas the two EPEC strains were identified as weak and moderate biofilm producers. However, no association was found between biofilm formation and persistence in the matrix. The findings provide an initial approach and provide relevant evidence of the capacity of STEC and EPEC strains to survive in sand, which could represent a potential risk in recreational environments. Full article

The most significant barrier against biopolymers’ commercialization is their sensitivity to external factors and poor material properties. In recent years, significant progress has been made to enhance these materials so that they are able to provide their unique physiological benefits while maintaining acceptable material performance. As these materials have developed, so too has their application in the food and medical industry, which often requires them to undergo sterilization. Sterilization is a process in which all microbial life and spores are removed from the surface and within materials and is a regulatory requirement for some food packaging products and all medical applications. Sterilization is carried out primarily using radiation, chemical, and heat treatment, which are all effective in disrupting cell regulation and causing cell death. These processes are known to induce structural and/or chemical changes in materials as well as potential migratory or leaching effects. This review aims to provide a comprehensive evaluation of these sterilization processes and the effects they have on polysaccharides, while established data is discussed that provides insight into their market viability post-sterilization and the importance of further characterization using sterilization. Full article

Instrument fracture during endodontic treatment significantly compromises treatment outcomes, with sodium hypochlorite (NaOCl) and other irrigants potentially affecting the cyclic fatigue resistance of nickel–titanium (NiTi) rotary files. This systematic review evaluated the impact of endodontic irrigants on NiTi instrument durability. A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, Embase, Cochrane Library, and WorldCat databases through June 2025, following PRISMA guidelines. Studies investigating cyclic fatigue resistance of NiTi rotary instruments exposed to various irrigants were included. Twenty-seven in vitro studies met the inclusion criteria, involving instruments across multiple file systems and irrigant solutions. The review revealed that NaOCl, particularly at concentrations ≥5% and elevated temperatures, significantly reduced cyclic fatigue resistance in most studies, with scanning electron microscopy confirming surface corrosion and microcrack formation. Heat-treated NiTi alloys demonstrated superior fatigue resistance compared to conventional austenitic alloys. Short-term NaOCl exposure (1–5 min) showed minimal impact, while prolonged exposure combined with autoclave sterilization produced cumulative weakening effects. Alternative irrigants such as EDTA and chlorhexidine showed more neutral effects on instrument integrity. These findings suggest that irrigant selection and exposure protocols significantly influence NiTi instrument longevity, with implications for clinical endodontic practice and instrument safety protocols. Full article

Lactic acid bacteria are beneficial for food biopreservation by inhibiting not only bacteria but also fungi. However, reports on the control of fungi, especially yeasts, by lactic acid bacteria are limited. In this study, strain 3121M0s derived from Mongolian traditional fermented milk, airag, was selected with relatively high antiyeast activity among 236 strains, and identified as Lactiplantibacillus plantarum. The activity was exhibited under acidic conditions and remained stable after heating. It was also highly resistant to catalase and proteases, indicating that the primary antiyeast substances of 3121M0s were neither H₂O₂ nor peptides. Then, organic acids (lactic acid, acetic acid, 4-hydroxyphenyllactic acid, 4-hydroxybenzoic acid, and 3-phenyllactic acid) were detected and quantified in the ethyl acetate extract of the 3121M0s culture supernatant. Among them, only acetic acid showed antiyeast activity on its own, and the activity was enhanced by lactic acid or 3-phenyllactic acid. Compared to the type strain of L. plantarum, the production of lactic acid from 3121M0s was almost equal, but acetic acid and 3-phenyllactic acid were about 1.5 times higher. These results suggest that strain 3121M0s would be useful as a biopreservative starter for fermented foods susceptible to yeast contamination due to being produced in open environments without final sterilization. Full article

Surgical procedures have significantly contributed to the increased life expectancy of the global population. The surgical procedures are carried out in specialised rooms within a healthcare facility normally designated as operating rooms or operating theatres. These rooms require meticulously designed heating, ventilating, and air conditioning systems to ensure optimal thermal comfort, strict sterility, and effective removal of airborne contaminants and anaesthetic gases. The performance of the system directly affects the risk of surgical site infections and associated post-operative complications. This study presents a computational fluid dynamics analysis of disturbance on airflow and particulate distribution within a representative operating room by the surgical staff and lighting fixtures concerning supply air velocity. The removal of the maximum possible particulate matter, precise control of air temperature and humidity, and unidirectional airflow in the surgical field were incorporated as key design strategies. The species transport model simulations revealed that while laminar airflow offers superior protection in terms of surgical site sterility, its performance is sensitive to disruptions caused by surgical lighting configurations and variations in supply air velocity. The findings highlight the complexities involved in maintaining optimal airflow conditions and underscore the need for integrative air conditioning design approaches that account for optimal design of surgical lighting and operational setups. Full article

High nighttime temperature (HNT) due to asymmetric diurnal warming threatens wheat productivity. This study evaluated the effect of HNT on wheat phenology, physiology, and yield through field and controlled environment experiments in Central Queensland, Australia. Two wheat genotypes, Faraday and AVT#6, were assessed under three sowing dates—1 May (Early), 15 June (Mid), and 1 August (Late)—within the recommended sowing window for the region. In a parallel growth chamber study, the plants were exposed to two nighttime temperature regimes, of 15 °C (normal) and 20 °C (high), with consistent daytime conditions from booting to maturity. Late sowing resulted in shortened vegetative growth and grain filling periods and increased exposure to HNT during the reproductive phase. This resulted in elevated floret sterility, lower grain weight, and up to 40% yield loss. AVT#6 exhibited greater sensitivity to HNT despite maturing earlier. Leaf gas exchange analysis revealed increased nighttime respiration (Rn) and reduced assimilation (A), resulting in higher Rn/A ratio for late-sown crops. The results from controlled environment chambers resembled trends of the field experiment, producing lower grain yield and biomass under HNT. Cumulative nighttime hours above 20 °C correlated more strongly with yield losses than daytime heat. These findings highlight the need for HNT-tolerant genotypes and optimized sowing schedules under future climate scenarios. Full article

This study aimed to evaluate and optimize the effects of three auxin types—indole-3-butyric acid (IBA), naphthaleneacetic acid (NAA), and indole-3-acetic acid (IAA)—applied at four concentrations (1000, 3000, 5000, and 8000 ppm) on the rooting performance of Photinia × fraseri Dress. stem cuttings. The experiment was conducted under controlled greenhouse conditions using a sterile perlite medium. Rooting trays were placed on bottom-heated propagation benches maintained at a set temperature of 25 ± 2 °C to stimulate root formation. However, the actual rooting medium temperature—measured manually every four days from the perlite zone using a calibrated thermometer—ranged between 18 °C and 22 °C, with an overall average of approximately 20 ± 2 °C. The average values of these root-zone temperatures were used in the statistical analyses. Rooting percentage, root number, root length, callus formation, and mortality rate were recorded after 120 days. In addition to classical one-way ANOVA, response surface methodology (RSM) was employed to model and optimize the interactions between auxin type, concentration, and temperature. The results revealed that 5000 ppm IBA significantly enhanced rooting performance, yielding the highest rooting percentage (85%), average root number (5.80), and root length (6.30 cm). RSM-based regression models demonstrated strong predictive power, with the model for rooting percentage explaining up to 92.79% of the total variance. Temperature and auxin concentration were identified as the most influential linear factors, while second-order and interaction terms—particularly T·ppm—contributed substantially to root length variation. These findings validate IBA as the most effective exogenous auxin for the vegetative propagation of Photinia × fraseri Dress. and provide practical recommendations for optimizing hormone treatments. Moreover, the study offers a robust statistical modeling framework that can be applied to similar propagation systems in woody ornamental plants. Full article

This study analyzes the thermal degradation of PVA and PVA/glycerol films in air under varying heating rates. Thermogravimetric analysis (TGA) of pure PVA in both air and inert atmospheres confirmed that oxidative conditions significantly influence degradation, particularly at lower heating rates. For PVA/glycerol films in air, deconvolution of the differential thermogravimetry (DTG) curves during the main degradation stage revealed distinct peaks attributable to the degradation of glycerol, PVA/glycerol complexes, and PVA itself. Isoconversional methods showed that, for pure PVA in air, the apparent activation energy (Ea) increased with conversion, suggesting the simultaneous occurrence of multiple degradation mechanisms, including oxidative reactions, whose contribution changes over the course of the degradation process. In contrast, under an inert atmosphere, Ea remained nearly constant, consistent with degradation proceeding through a single dominant mechanism, or through multiple steps with similar kinetic parameters. For glycerol-plasticized films in air, Ea exhibited reduced dependence on conversion compared with that of pure PVA in air, with values similar to those of pure PVA under inert conditions. These results indicate that glycerol influences the oxidative degradation pathways in PVA films. These findings are relevant to high-temperature processing of PVA-based materials and to the design of thermal treatments—such as sterilization or pyrolysis—where control over degradation mechanisms is essential. Full article

Solid-state fermentation (SSF) involves the growth of microorganisms on solid substrates, mimicking natural environments of many species. Due to sustainability concerns, transforming agro-industrial by-products into value-added products through SSF has been increasingly studied. Brewer’s spent grain (BSG), the main by-product of beer production, mostly consists of barley grain husks, making BSG a great support for microorganism cultivation. Although autoclaving remains the standard sterilization and pretreatment method of substrates, electric field technologies and their attendant ohmic heating (OH) have great potential as an alternative technology. In the present work, pretreatment of BSG by OH was explored in SSF with Aspergillus niger to produce commercially valuable enzymes. OH favored the solubilization of phenolic compounds, total protein, and reducing sugars significantly higher than autoclaving. SSF of treated BSG led to the production of lignocellulosic enzymes, with xylanases being the most active, reaching 540 U/g, a 1.5-fold increase in activity compared to autoclaved BSG. Protease activity was also improved 1.6-fold by OH, resulting in 49 U/g. Our findings suggest that OH treatment is an effective alternative to autoclaving and that its integration with SSF is a sustainable strategy to enhance by-product valorization through enzyme production with many industrial applications, according to circular economy guidelines. Full article

The global energy sector is aiming to substantially reduce CO₂ emissions to meet the UN climate goals. Among the proposed strategies, underground storage solutions such as radioactive disposal, CO₂, NH₃, and underground H₂ storage (UHS) have emerged as promising options for mitigating anthropogenic emissions. These approaches require rigorous research and development (R&D), often involving laboratory-scale experiments to establish their feasibility before being scaled up to pilot plant operations. Microorganisms, which are ubiquitous in laboratory environments, can significantly influence geochemical reactions under variable experimental conditions of porous media and a salt cavern. We have selected a consortium composed of Bacillus sp., Enterobacter sp., and Cronobacter sp. bacteria, which are typically present in the laboratory environment. These microorganisms can contaminate the rock sample and develop experimental artifacts in UHS experiments. Hence, it is pivotal to sterilize the rock prior to conduct experimental research related to effects of microorganisms in the porous media and the salt cavern for the investigation of UHS. This study investigated the efficacy of various disinfection and sterilization methods, including ultraviolet irradiation, autoclaving, oven heating, ethanol treatments, and gamma irradiation, in removing the microorganisms from silica sand. Additionally, the consideration of their effects on mineral properties are reviewed. A total of 567 vials, each filled with 9 mL of acid-producing bacteria (APB) media were used to test killing efficacy of the cleaning methods. We conducted serial dilutions up to 10⁻⁸ and repeated them three times to determine whether any deviation occurred. Our findings revealed that gamma irradiation and autoclaving were the most effective techniques for eradicating microbial contaminants, achieving sterilization without significantly altering the mineral characteristics. These findings underscore the necessity of robust cleaning protocols in hydrogeochemical research to ensure reliable, reproducible data, particularly in future studies where microbial contamination could induce artifacts in laboratory research. Full article

Forage legumes often show poor growth, the cause of which is not always immediately apparent to the farmer. The aim of the present study was the development of a diagnostic tool to identify possible causes for unexplained forage legume decline. A modified diagnostic test was carried out under a controlled environment using red clover (Trifolium pratense L.) as a test plant. Soil samples from three organic farms in Germany showing decline in productivity of forage legumes were tested using (i) an untreated control, (ii) application of a nutrient solution to investigate nutrient deficiencies, (iii) amendment with activated charcoal to immobilize toxic compounds, and (iv) heat sterilization to eliminate detrimental organisms. In addition, plant and soil samples from the three study sites were analyzed for pathogens and nutrient levels in the laboratory. At all the sites, plants growing in the sterilized soil showed an improvement in growth, indicating the presence of pathogens in the soil as the main cause for red clover decline. Hints at nutrient deficiency and a minor effect of phytotoxic compounds were found in addition to detrimental organisms at one studied site, indicating an interaction of abiotic and biotic factors as the cause of clover decline. The fertilization with a nutrient solution led to stunted growth at one site, which could be associated with a negative effect of nitrogen application on red clover and nutrient imbalances. The results of the bioassay were corroborated by the plant screening for pathogens and nutrient levels analyses. The diagnostic test proved to be a reliable tool for identifying possible causes of red clover decline, such as harmful organisms or, to a lesser extent, nutrient deficiencies. Full article

For the calculation of thermal processes of canned food, the original formula method of Ball is still widely used for its accuracy and safety. However, it requires the consultation of tables that Ball prepared and the relative interpolation of the data. This is due to the exponential integral function (Ei) resulting after the integration of the thermo-bacteriological and heat transfer differential equations. Mathematical modelling that replaces the Ball tables is useful for speeding up the thermal process calculations and for being prospectively implemented in process control systems. Stoforos had already proposed a simple and accurate mathematical model based on the regression of the table data. However, Stoforos’ equations do not contain the influence of the temperature difference between the steam and the cold water (m+g) when this is different from the two values of the tables (180 and 130 °F). This approximation leads, in some cases, to over-sterilization with a consequent loss of quality. To overcome these limitations, in this work a nonlinear regression of the values of the exponential integral function (Ei) has been developed. However, this is performed by using the regression on the ratio between the function and its derivative and replacing the hyperbola of the initial cooling imposed by Ball with an appropriate exponential function. The overall mean relative error, MRE, compared to Ball’s tables was less than 1%. Full article

Background/Objectives: Alternative therapies for urinary tract infections (UTIs) have been explored, but their efficacy remains inconsistent. With rising antibiotic resistance, this study aimed to evaluate simplified postbiotic formulations derived from heat-killed probiotics for long-term protection against primary and recurrent UTIs in a murine model. Methods: We compared a multi-strain (seven-strain) versus a single-strain postbiotic in preventing Escherichia coli-induced UTIs and recurrent polymicrobial UTIs, assessed protection persistence after treatment discontinuation, and established a novel sustained UTI model via intravesical co-inoculation of three uropathogens. Mice were allocated to three experimental groups: a placebo group (PBS), Postbiotic I group (a seven-strain heat-killed probiotic formulation), and Postbiotic II group (a single-strain heat-killed probiotic). After two weeks of treatment, mice were challenged with uropathogenic E. coli (UPEC) and treated for seven days. Following a 14-day washout and bacterial clearance, they were rechallenged with multidrug-resistant UPEC, Klebsiella pneumoniae, and Staphylococcus pseudintermedius. Results: Both postbiotics significantly accelerated bacterial clearance in primary UTIs (p < 0.05). In recurrent UTIs, placebo-treated mice exhibited persistent bacteriuria, while Postbiotic I maintained a significantly higher sterile urine rate (50–80%, p < 0.01) post-treatment. Histopathological analysis confirmed reduced bladder and kidney inflammation (p < 0.05) with Postbiotic I. Conclusions: These findings demonstrate the superior efficacy of Postbiotic I in mitigating UTIs, with sustained protection post-treatment, supporting its potential as a long-term, non-antibiotic strategy. Additionally, our reproducible chronic UTI model, achieved through the co-inoculation of three uropathogens, provides a valuable tool for future research on chronic UTI pathogenesis and treatment. Full article

Background: Pharmaceutical compounding remains a predominantly manual process with limited innovation, particularly in non-sterile applications. This study explores the implementation of an automated compounding platform based on 3D printing to enhance precision, efficiency, and adaptability in pediatric corticosteroid formulations. Methods: Personalized hydrocortisone dosage forms were prepared in a hospital pharmacy setting using a proprietary excipient base and standardized procedures, including automated dosing and syringe heating when required. Three dosage forms—3.2 mg gel tablets, 2.8 mg water-free troches, and 1.2 mg orodispersible films (ODFs)—were selected to demonstrate the platform’s versatility and to address pediatric needs for varying strengths and dosage types. All products were prepared using a reproducible semi-solid extrusion (SSE)-based workflow with the consistent API-excipient blending and automated deposition. Results: Analytical testing confirmed that all formulations met pharmacopeial criteria for mass and content uniformity. The ODF and troche forms achieved rapid drug release, exceeding 75% within 5 min, while the gel tablet showed a slower release profile, reaching 86% by 60 min. Additionally, in-process homogeneity testing across syringe printing cycles confirmed the consistent API distribution. Conclusions: The results support the feasibility of integrating automated compounding technologies into pharmacy workflows. Such systems can improve accuracy, minimize variability, and streamline the production of customized pediatric medications, particularly for drugs with poor palatability or narrow therapeutic windows. Overall, this study highlights the potential of automation to modernize non-sterile compounding, and to better support individualized therapy. Full article