pH Fluctuations Research Articles

Meta-analysis Driven Strain Design for Mitigating Oxidative Stresses Important in Biomanufacturing.

As the availability of data sets increases, meta-analysis leveraging aggregated and interoperable data types is proving valuable. This study leveraged a meta-analysis workflow to identify mutations that could improve robustness to reactive oxygen species (ROS) stresses using an industrially important melatonin production strain as an example. ROS stresses often occur during cultivation and negatively affect strain performance. Cellular response to ROS is also linked to the SOS response and resistance to pH fluctuations, which is important to strain robustness in large-scale biomanufacturing. This work integrated more than 7000 E. coli adaptive laboratory evolution (ALE) mutations across 59 experiments to statistically associate mutated genes to 2 ROS tolerance ALE conditions from 72 unique conditions. Mutant oxyR, fur, iscR, and ygfZ were significantly associated and hypothesized to contribute fitness in ROS stress. Across these genes, 259 total mutations were inspected in conjunction with transcriptomics from 46 iModulon experiments. Ten mutations were chosen for reintroduction based on mutation clustering and coinciding transcriptional changes as evidence of fitness impact. Strains with mutations reintroduced into oxyR, fur, iscR, and ygfZ exhibited increased tolerance to H2O2 and acid stress and reduced SOS response, all of which are related to ROS. Additionally, new evidence was generated toward understanding the function of ygfZ, an uncharacterized gene. This meta-analysis approach utilized aggregated and interoperable multiomics data sets to identify mutations conferring industrially relevant phenotypes with the least drawbacks, describing an approach for data-driven strain engineering to optimize microbial cell factories.

The effect of free and encapsulated probiotic bacteria on some physicochemical, microbiological, and textural properties of apricot leather (pestil) during storage.

Pestil, also known as fruit leather, has emerged as a promising non-dairy carrier for probiotics, utilizing apricots and incorporating probiotics into its formulation. This study aimed to develop a healthy snack bar by incorporating three distinct strains of probiotic bacteria, both in free and encapsulated forms, into the recipe of apricot leather. The physicochemical, bioactive, microbiological, and textural attributes of the resulting apricot pestils were evaluated over a 120-day storage period. Fluctuations in pH (4.74-4.97) were observed during storage, whereas water activity (0.31-0.45) and moisture content (8.05%-13.40%) exhibited a decreasing trend over time. Incorporating free or encapsulated bacteria resulted in a darker surface, attributed to the intermolecular interactions between probiotics and the pestil matrix. The initial total phenolic content was highest and declined significantly during storage (52.13-291.73mg gallic acid equivalent/100g) (p<0.05). Viability was found to be higher in the encapsulated forms of bacteria at the conclusion of the storage period. Overall, apricot pestil emerged as a promising matrix for viable probiotics, facilitating their delivery and hosting in both free and encapsulated forms during storage.

Treatment of real carwash wastewater using high-efficiency and energy-saving electrocoagulation technique

This study focused on the treatment of actual wastewater from a car wash facility using electrocoagulation. The primary objective was to decrease chemical oxygen demand (COD) and eliminate turbidity by employing various electrodes such as Stainless Steel (SS) 304, Galvanized Iron (GI), and aluminum foil (α-Al) in a batch configuration. Several factors including contact time, current density, initial pH, and electrode material were examined to optimize process efficiency. The sludge generated during electrocoagulation was analyzed using Scanning Electron Microscopy/Energy-Dispersive X-ray Spectrometry (SEM-EDS). The results indicated that COD removal efficiency initially decreased between 30 and 60 min before improving. The data for COD, turbidity, and total phosphate reduction aligned well with the pseudo-first-order kinetic model, with R2 values of 0.275, 0.898, and 0.522, respectively. Minor variations were observed in pH, Total Dissolved Solids (TDS), Electrical Conductivity (EC), and alkalinity, while the temperature increased from 12 to 18.6 °C. Optimal removal efficiency for turbidity, total phosphate, and COD was achieved at pH = 6. The study demonstrated that higher current density resulted in enhanced COD reduction and turbidity removal. Chloride levels decreased with increasing applied current. The α-Al electrode exhibited superior performance compared to SS 304 and GI electrodes, with notable pH fluctuations during the process. UV–visible absorption spectra indicated differences in treated wastewater patterns based on the electrode utilized. SEM analysis revealed distinct characteristics of sludge produced by different electrodes. Energy and electrode consumption varied among the electrodes, with SS 304 displaying the lowest values.

Plasma Electrolytes Response in Mud Catfish, Clarias gariepinus (Burchell 1822) exposed to Different Regimes of Salinity and pH

Introduction: Aquatic organisms, especially fish, are highly sensitive to environmental changes that can profoundly affect their physiological processes essential for survival. Physico-chemical factors such as salinity and pH exert significant influences on osmoregulation and ion balance, which are critical for maintaining cellular homeostasis in fish. Aims: This study aims to explore how varying levels of salinity and pH affect plasma electrolyte concentrations in Clarias gariepinus, focusing on potassium (K+), sodium (Na+), chloride (Cl−), and bicarbonate (HCO3−) ions. The objective is to understand the physiological responses of C. gariepinus to these environmental factors and their potential as biomarkers for assessing aquatic ecosystem health. Materials and Methods: Juvenile C. gariepinus was exposed to different salinity levels (4 ‰, 6 ‰, 8 ‰) and pH levels (4, 6, 8) over 21 days. Plasma electrolyte concentrations were measured using an SFRI ISE 6000 Electrolyte Analyser. Statistical analysis included ANOVA and DMRT to identify significant differences (p &lt; 0.05) among experimental groups. Results: The study found significant variations in K+, Cl−, Na+, and HCO3- concentrations in C. gariepinus across different salinity and pH conditions. K+ levels decreased with increasing salinity, indicating stress-induced responses, while pH variations had less pronounced effects on K+ regulation. Cl− concentrations increased with higher salinity levels, suggesting adaptive osmoregulatory strategies. Na+ levels showed significant fluctuations across salinity and pH conditions, whereas HCO3− levels responded uniquely to changes in these parameters, demonstrating adaptive mechanisms in acid-base balance. Conclusion: This research underscores the adaptive responses of C. gariepinus to fluctuations in salinity and pH, highlighting their ability to maintain plasma electrolyte balance under varying environmental conditions. These findings contribute to understanding the ecophysiological adaptations of C. gariepinus and suggest the potential utility of plasma electrolytes as biomarkers for assessing the health of aquatic ecosystems.

Development of a novel ratiometric fluorescent probe for real-time monitoring of acidic pH and its applications in food samples and biosystem

In this research, a high-efficiency ratiometric fluorescent probe TZTF for sensitive detecting the fluctuations of acidic pH was synthesized. The fluorescent color changed from bright blue to orange in the pH values range from 8.0 to 1.0 with the pKa value of 5.41. Meanwhile, the probe demonstrated excellent selectivity, good anti-interference ability, prominent reversibility, outstanding photostability, and low cytotoxicity. The detection mechanism of TZTF towards acidic pH was verified through 1H NMR analysis and DFT calculation. Additionally, probe TZTF was also applied to evaluate the freshness of meat samples, as the pH value of meat samples may decrease if they are not stored properly, and the subsequent acid-catalyzed denaturation of proteins may pose a threat to human health through the food chain. More importantly, fluorescence imaging experiments confirmed that TZTF is appropriate for real-time tracking of pH variations in living cells and living zebrafish.

Contrast in larval sensitivity to low pH in sea urchins from neighbouring seagrass meadows at Inhaca Island, Mozambique

Ocean acidification presents a major threat to marine life, and a large body of evidence has documented its negative effects on various marine species and ecosystems. Recent meta-analyses highlight the key role of local adaptation and have linked species’ sensitivity to extremes of the present range of pH variability. More specifically, ‘physiological tipping points’ can be correlated with the lowest experienced pH where the organisms live. We verified this hypothesis by comparing the responses of larvae of the collector urchin Tripneustes gratilla originating from two neighbouring seagrass meadows at Inhaca Island in southern Mozambique. The two seagrass meadows experience different conditions: the site at the Inhaca Marine Biology Research Station (Estação de Biologia Marítima de Inhaca, EBMI) is subtidal, and the site at Banguá is intertidal. Larvae of adults collected from the two sites were cultured in the laboratory under four different target pH treatments (8.04, 7.67, 7.46 and 7.29) for 7 days. The results showed an overall negative effect of lower pH on survival and growth as well as on an index of symmetry. Larvae originating from the intertidal seagrass habitat at Banguá which experiences large pH fluctuations were more sensitive to a lower pH than those from the subtidal seagrass habitat at EBMI. This finding suggests that different mechanisms for pH tolerance and local adaptation may apply in subtidal versus intertidal environments. Consequently, the unifying principle that physiological tipping points are correlated with the extreme low pH in the present range of variability, may reach its limit in increasingly extreme environments under natural conditions.

Fluctuations in equine cutaneous pH and transepidermal water loss with time of day and ambient conditions

Cutaneous pH and transepidermal water loss (TEWL) are commonly utilized measures in dermatological research as they provide information concerning barrier function. The importance of dermal health has become more evident in recent years. Accordingly, the aim of this work was to identify natural fluctuations in the biophysical parameters of healthy equine skin. Cutaneous pH and TEWL was collected on nine mares at 6:00 AM, 12:00 PM, and 6:00 PM daily for five days on the nose, withers, girth area, mid-back, and base of tail. Ambient temperature and humidity were measured at each collection. Statistical analysis was completed using SAS On Demand. Tests included repeated measures, ANOVA, and regression analysis. Mean cutaneous pH significantly differed by day (P = 0.0052) and time (P = 0.0073) but was unaffected by anatomical location (P = 0.2841). Interestingly, cutaneous pH had a significant interaction of day and location (P = 0.0004). Mean TEWL measures significantly differed by day (P < 0.0001), time (P < 0.0001), and anatomical location (P = 0.0231). Interaction of day and time had a significant effect on TEWL (P < 0.0001) and also resulted in a three-way interaction of day, time, and location (P = 0.0167). There were no significant associations of pH with temperature and humidity. All measures of TEWL across all locations were significantly correlated with temperature and humidity (P < 0.0001). Cutaneous pH and TEWL measures are affected by environmental conditions which should be considered in future models and work using dermal characteristics of horses.

PH-dependent mechanisms of sulfadiazine degradation by natural pyrite-driven heterogeneous Fenton-like reactions

The development of a natural pyrite/peroxymonosulfate (PMS) system for the removal of antibiotic contamination from water represented an economic and green sustainable strategy. Yet, a noteworthy knowledge gap remained considering the underlying reaction mechanism of the system, particularly in relation to its pH sensitivity. Herein, this paper investigated the impacts of critical reaction parameters and initial pH levels on the degradation of sulfadiazine (SDZ, 3 mg/L) in the pyrite/PMS system, and elucidated the pH dependence of the reaction mechanism. Results showed that under optimal conditions, SDZ could be completely degraded within 5 min at a broad pH range of 3.0–9.0, with a pseudo-first-order reaction rate of >1.0 min−1. The low or high PMS doses could lower degradation rates of SDZ through the decreased levels of active species, while the amount of pyrite was positively correlated with the removal rate of SDZ. The diminutive concentrations of anions exerted minor impacts on the decomposition of SDZ within the pyrite PMS system. Mechanistic results demonstrated that the augmentation of pH levels facilitated the transition from the non-radical to the radical pathway within the natural pyrite/PMS system, while concurrently amplifying the role of •OH in the degradation process of SDZ. This could be attributed to the change in interface electrostatic repulsion induced by pH fluctuations, as well as the mutual transformation between active species. The stable presence of the relative content of Fe(II) in the used pyrite was ensured owing to the reduced sulfur species acting as electron donors, providing the pyrite/PMS system excellent reusability. This paper sheds light on the mechanism regulation of efficient removal of organic pollutants through pyrite PMS systems, contributing to practical application.

Efficient removal of nanoplastics from industrial wastewater through synergetic electrophoretic deposition and particle-stabilized foam formation

Microplastic particles have been discovered in virtually all ecosystems worldwide, yet they may only represent the surface of a much larger issue. Nanoplastics, with dimensions well below 1 µm, pose an even greater environmental concern. Due to their size, they can infiltrate and disrupt individual cells within organisms, potentially exacerbating ecological impacts. Moreover, their minute dimensions present several hurdles for removal, setting them apart from microplastics. Here, we describe a process to remove colloidally stable nanoplastics from wastewater, which synergistically combines electrophoretic deposition and the formation of particle-stabilized foam. This approach capitalizes on localized changes in particle hydrophilicity induced by pH fluctuations resulting from water electrolysis at the electrode surface. By leveraging these pH shifts to enhance particle attachment to nascent bubbles proximal to the electrode, separation of colloidal particles from aqueous dispersions is achieved. Using poly(methyl methacrylate) (PMMA) colloidal particles as a model, we gain insights into the separation mechanisms, which are subsequently applied to alternative model systems with varying surface properties and materials, as well as to real-world industrial wastewaters from dispersion paints and PMMA fabrication processes. Our investigations demonstrate removal efficiencies surpassing 90%.

Tunicate cellulose nanocrystals strengthened injectable stretchable hydrogel as multi-responsive enhanced antibacterial wound dressing for promoting diabetic wound healing

The intricate microenvironment of diabetic wounds characterized by hyperglycemia, intense oxidative stress, persistent bacterial infection and complex pH fluctuations hinders the healing process. Herein, an injectable multifunctional hydrogel (QPTx) was developed, which exhibited excellent mechanical performance and triple responsiveness to pH, temperature, and glucose due to dynamic covalent cross-linking involving dynamic Schiff base bonds and phenylboronate esters with phenylboronic-modified quaternized chitosan (QCS-PBA), polydopamine coated tunicate cellulose crystals (PDAn@TCNCs) and polyvinyl alcohol (PVA). Furthermore, the hydrogels can incorporate insulin (INS) drugs to adapt to the complex and variable wound environment in diabetic patients for on-demand drug release that promote diabetic wound healing. Based on various excellent properties of the colloidal materials, the hydrogels were evaluated for self-healing, rheological and mechanical properties, in vitro insulin response to pH/temperature/glucose release, antibacterial, antioxidant, tissue adhesion, coagulation, hemostasis in vivo and in vitro, and biocompatibility and biodegradability. By introducing PDAn@TCNCs particles, the hydrogel has photothermal antibacterial activity, enhanced adhesion and oxidation resistance. We further demonstrated that these hydrogel dressings significantly improved the healing process compared to commercial dressings (Tegaderm™) in full-layer skin defect models. All indicated that the glucose-responsive QPTx hydrogel platform has great potential for treating diabetic wounds.

Comparison of sea buckthorn fruit oil nanoemulsions stabilized by protein-polysaccharide conjugates prepared using β-glucan from various sources

To understand the influence of β-glucans structure on the emulsifying properties of protein-polysaccharide conjugates, sodium caseinate (NaCas) was utilized to form glycosylation conjugates with varying degrees of glycosylation (10.68–17.50%) using three β-glucans from bacteria, yeast, and oats. This process induced alterations in the secondary structure of protein. The nanoemulsions prepared with the glycosylated conjugates exhibited superior stability compared to those formulated solely with NaCas, particularly under conditions of drastic pH fluctuations and extended storage periods. The nanoemulsion prepared with the NaCas-Salecan conjugate demonstrated exceptional stability at pH 4 and 6, or storage for 20 days. Additionally, it significantly attenuated the oxidation of unsaturated fatty acids and exhibited the lowest levels of aggregation, flocculation, and free fatty acid release rate during in vitro digestion. This study suggested the potential of the NaCas-Salecan conjugates in enhancing the stability of nanoemulsions and facilitating the colorectal-targeted delivery of sea buckthorn fruit oil.

Smart bilayer film: Quality monitoring for freshness of fish and minced pork delights

Global concern over food spoilage and the pressing need for efficient spoilage detection methods have far-reaching implications for the well-being of millions of people worldwide. So, the emergence of systems capable of providing early detection and visible evidence of food spoilage has gained recognition as an essential tool in the fight against food spoilage. A smart bilayer label (SBL) was developed, which exhibits distinctive qualities, encompassing robust antioxidant and antimicrobial characteristics, responsive color alteration triggered by minor pH fluctuations, and the capability to exhibit color changes upon exposure to acetic acid and ammonia gas. The SBL shows robustness regarding mechanical, thermal, and barrier properties, including water and oxygen resistance and overall hydrophilicity. The ability of SBL to detect the freshness of fresh fish and minced pork at 6 °C was determined. Over time, for both fish and pork, an increase in pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and total viable counts (TVC) were detected. Notably, SBL changed to green on days 8 and 10 for fish and minced pork, respectively, corresponding to pH ranges of 7, indicating spoilage. This study validates the SBL as an effective freshness indicator, with a color change discernible to the naked eye (ΔE > 12), and highlights its potential for monitoring the quality of protein-rich products. Strong positive correlations between pH, TVB-N, TVC, and storage time underscore their interdependence (P < 0.01). The SBL’s ΔE positively correlates with pH, TVB-N, and TVC, affirming its effectiveness as a visual freshness indicator. These insights advance our understanding of the evolution of meat quality and endorse the SBL's role in real-time monitoring and enhancing meat industry practices.

A Universal Coulombic Efficiency Compensation Strategy for Zinc-Based Flow Batteries.

Alkaline zinc-iron flow batteries (AZIFBs) are well suited for energy storage because of their good safety, high cell voltage, and low cost. However, the occurrence of irreversible anodic parasitic reactions results in a diminished coulombic efficiency (CE), unbalanced charge state of catholyte/anolyte and subsequently, a poor cycling performance. Here, a universal CE compensation strategy centered around the oxygen evolution reaction (OER) on the cathodic side, is reported. This strategy aims to equalize the charge state of the [Fe(CN)6]3-/4--based catholyte and counteract pH fluctuations. The OER process can be implemented either directly on the electrode through electrochemical reaction or in an external catalytic reactor column via a redox-mediated process. This innovative approach effectively mitigates the gradual accumulation of [Fe(CN)6]3- in discharged catholyte and [Zn(OH)4]2- in charged anolyte by consuming the extra OH- during a continuous cycling process. As a result, AZIFBs demonstrate exceptional cycling performance with an extremely low capacity fading rate of 0.0128%/day (or 0.0005%/cycle) over 600 cycles at 80% state of charge (SOC). The proposed CE compensation strategy not only provides an effective way to address the CE loss issue for AZIFBs, but also can be applied to diverse battery technologies encountering CE loss caused by water/oxygen-induced parasitic reactions.

Prototype of pH and Water Temperature Control System in Discus Fish Farming Using IoT-based Sugeno Fuzzy

Challenges in cultivating discus fish often arise from abrupt pH and temperature fluctuations attributed to manual and sluggish intervention. An IoT-based prototype for automatic pH and water temperature regulation was developed to address this. The study aimed to evaluate the efficacy of the prototype in controlling pH levels and water temperature and to explore the application of IoT-based fuzzy logic in discus fish cultivation. Test data from the implemented tools and sensors revealed an error comparison value of 0.0132% and an accuracy level of 99.986% for pH measurement. In comparison, temperature sensing yielded an error value of 0% with 100% accuracy. The IoT-based fuzzy Sugeno system demonstrated regular and effective operation in regulating pH and water temperature in discus fish cultivation, showcasing superiority over manual handling systems in mitigating sudden environmental changes.

Temporal and Spatial Dynamics of Vibrio harveyi: An Environmental Parameter Correlation Investigation in a 4-Metre-Deep Dicentrarchus labrax Aquaculture Tank.

Nowadays, European seabass (Dicentrarchus labrax) aquaculture is undergoing a significant expansion. Nevertheless, the aquaculture industry is plagued by vibriosis. The spatial and temporal dynamics of Vibrio harveyi were studied on a European seabass farm in northern France during seven months of 2022. Concrete specimens were suspended and water was pumped from different depths (0.3 m, 2.15 m and 4 m deep), providing insights into the biofilm and planktonic V. harveyi dynamics. The abundances of V. harveyi, in the biofilm and free-living forms, were positively correlated. The water parameters revealed seasonal fluctuations in temperature, pH, and salinity, with no significant differences observed across the water column. Quantification of V. harveyi revealed no significant differences between depths, but seasonality, with peak abundances observed in August, correlated with temperature increases. Principal component analysis identified temperature as a primary driver, but also additional parameters, such as salinity and pH. Vibriosis occurred during the sampling period, providing valuable insights into the conditions before, during, and after the outbreaks. This study underscores the importance of understanding V. harveyi behaviour in aquaculture, particularly in the context of global warming, for effective disease management and sustainable practices.

Antibacterial, cytotoxic and mechanical properties of a orthodontic cement with phosphate nano-sized and phosphorylated chitosan: An in vitro study

ObjectivesEvaluate, in vitro, the effect of incorporating nano-sized sodium trimetaphosphate (TMPnano) and phosphorylated chitosan (Chi-Ph) into resin-modified glass ionomer cement (RMGIC) used for orthodontic bracket cementation, on mechanical, fluoride release, antimicrobial and cytotoxic properties. MethodsRMGIC was combined with Chi-Ph (0.25%/0.5%) and/or TMPnano (14%). The diametral compressive/tensile strength (DCS/TS), surface hardness (SH) and degree of conversion (%DC) were determined. For fluoride (F) release, samples were immersed in des/remineralizing solutions. Antimicrobial/antibiofilm activity was evaluated by the agar diffusion test and biofilm metabolism (XTT). Cytotoxicity in fibroblasts was assessed with the resazurin method. ResultsAfter 24 h, the RMGIC-14%TMPnano group showed a lower TS value (p < 0.001); after 7 days the RMGIC-14%TMPnano-0.25%Chi-Ph group showed the highest value (p < 0.001). For DCS, the RMGIC group (24 h) showed the highest value (p < 0.001); after 7 days, the highest value was observed for the RMGIC-14%TMPnano-0.25%Chi-Ph (p < 0.001). RMGIC-14%TMPnano, RMGIC-14%TMPnano-0.25%Chi-Ph, RMGIC-14%TMPnano-0.5%Chi-Ph showed higher and similar release of F (p > 0.001). In the SH, the RMGIC-0.25%Chi-Ph; RMGIC-0.5%Chi-Ph; RMGIC-14%TMPnano-0.5%Chi-Ph groups showed similar results after 7 days (p > 0.001). The RMGIC-14%TMPnano-0.25%Chi-Ph group showed a better effect on microbial/antibiofilm growth, and the highest efficacy on cell viability (p < 0.001). After 72 h, only the RMGIC-14%TMPnano-0.25%Chi-Ph group showed cell viability (p < 0.001). ConclusionThe RMGIC-14%TMPnano-0.25%Chi-Ph did not alter the physical-mechanical properties, was not toxic to fibroblasts and reduced the viability and metabolism of S. mutans. Clinical relevanceThe addition of phosphorylated chitosan and organic phosphate to RMGIC could provide an antibiofilm and remineralizing effect on the tooth enamel of orthodontic patients, who are prone to a high cariogenic challenge due to fluctuations in oral pH and progression of carious lesions.

SntB Affects Growth to Regulate Infecting Potential in Penicillium italicum.

Penicillium italicum, a major postharvest pathogen, causes blue mold rot in citrus fruits through the deployment of various virulence factors. Recent studies highlight the role of the epigenetic reader, SntB, in modulating the pathogenicity of phytopathogenic fungi. Our research revealed that the deletion of the SntB gene in P. italicum led to significant phenotypic alterations, including delayed mycelial growth, reduced spore production, and decreased utilization of sucrose. Additionally, the mutant strain exhibited increased sensitivity to pH fluctuations and elevated iron and calcium ion stress, culminating in reduced virulence on Gannan Novel oranges. Ultrastructural analyses disclosed notable disruptions in cell membrane integrity, disorganization within the cellular matrix, and signs of autophagy. Transcriptomic data further indicated a pronounced upregulation of hydrolytic enzymes, oxidoreductases, and transport proteins, suggesting a heightened energy demand. The observed phenomena were consistent with a carbon starvation response potentially triggering apoptotic pathways, including iron-dependent cell death. These findings collectively underscored the pivotal role of SntB in maintaining the pathogenic traits of P. italicum, proposing that targeting PiSntB could offer a new avenue for controlling citrus fungal infections and subsequent fruit decay.

Intelligent Magnetic Microrobots with Fluorescent Internal Memory for Monitoring Intragastric Acidity

AbstractThis study investigates the dynamic fluctuations of pH caused by gastric acid secretion, a process of both biological and clinical significance, with microrobots. Abnormal patterns of acidity often indicate gastrointestinal diseases, underlying the importance of precise intragastric pH monitoring. Traditional methods using fluorescent probes face challenges due to their faint solid‐state fluorescence, limited target specificity, and accuracy. To overcome these obstacles, pH‐responsive fluorescent organic microparticles decorated with magnetite (Fe3O4) nanoparticles are engineered. These microrobots exhibit a unique fluorescence switching capability at a critical pH, enabling the monitoring of gastric acidity. The magnetic part of these microrobots ensures magnetic maneuverability to enable targeted navigation. The microrobots’ fluorescence switching mechanism is elucidated through comprehensive spectroscopy, microscopy, and X‐ray diffraction analyses, revealing molecular‐level structural transformations upon interaction with gastric acid and antacids. These transformations, specifically protonation and deprotonation of the microrobots’ fluorescent components, prompt a distinct fluorescence response correlating with pH shifts. In vitro and ex vivo experiments, simulating stomach conditions, confirm the microrobots’ efficacy in pH‐responsive imaging. The results showcase the promising diagnostic potential of microrobots for gastrointestinal tract diseases, marking a significant advancement in imaging‐based medical diagnostics at targeted locations.

Exploring Endogenous Processes in Water Supply Systems: Insights from Statistical Methods and δ18O Analysis

Water used for water supply undergoes numerous changes that affect its composition prior to entering the water supply system (WSS). Once it enters the WSS, it is subject to numerous influences altering its physical and chemical composition, redox potential, and microbial quality. Observations of water quality parameters at different locations within the WSS indicate that it is justified to assume that these processes take place from the source to the end user. In this study, we used the results of routine everyday analyses (EC, T, pH, ORP, chloride, nitrate, nitrite, ammonium, and bacteria) supplemented by experimental data from a one-year sampling campaign assessing the main cations and anions and stable isotopes δ2H and δ18O. Through these data, the statistical significance of the differences between the concentrations of the basic water quality parameters among different WSS locations was determined, together with the water retention time in the system. The results indicate minor changes in water chemical composition within the observed WSS, remaining below the prescribed Maximum Contaminant Level (MCL) for human consumption. However, factors such as water retention time, CaCO3 deposition, pH fluctuations, and bacterial growth may influence its suitability, which necessitates further investigation into potential risks affecting water quality.

The legal norms of the European Union regarding the prevention of foodborne listeriosis, consumer risk assessment, diagnostic methods, and identification of Listeria spp.

Listeria monocytogenes is a common bacterium due to its high adaptability. The pathogen can survive in adverse conditions, making monitoring very difficult. Listeria monocytogenes belongs to the Gram-positive group of bacteria that are relatively anaerobic and exhibit a characteristic tipping movement. There are 6 species in the genus Listeria, but only one – Listeria monocytogenes, under favorable conditions, can cause a disease called listeriosis in humans. The pathogen can grow in aerobic and anaerobic conditions at 0 to 40 °C temperatures. Can survive in adverse conditions, for example, low or high temperature, with a wide range of pH fluctuations or high salinity of the product. Thus, refrigeration conditions (0–4 °C), where we often store manufactured food or raw materials necessary for production, can be ideal for developing Listeria monocytogenes. The pathogen is transmitted through water, soil, infected plants, food, feed, sewage (feces), and meat from farmed or wild animals. To prevent the spread of Listeria monocytogenes. Food manufacturers must comply with national and European Union legal norms regarding producing and selling microbiologically safe food products. Commission Regulation (EC) No. 2073/2005 defines in detail the criteria for limiting the number of Listeria monocytogenes, which must meet the maximum permissible standards according to the type and consumer purpose of the food product. Adherence to the rules of correct hygiene steps in agrarian firms guarantees that products and raw materials of animal and plant origin will be of proper quality with excellent sanitary and hygienic indicators. The mandatory introduction of the HACCP system is an effective tool for analyzing the risks associated with the processing and production of food products, which makes it possible to guarantee freshness, quality, and safety. HACCP must be applied throughout the entire production chain up to the final consumption and is based primarily not on the control of the final product, but on the prevention of risks.