Metabolomics reveals high fructose-1,6-bisphosphate from fluoride-resistant Streptococcus mutans.

BACKGROUND: Fluoride-resistant Streptococcus mutans (S. mutans) strains have developed due to the wide use of fluoride in dental caries prevention. However, the metabolomics of fluoride-resistant S. mutans remains unclear. OBJECTIVE: This study aimed to identify metabolites that discriminate fluoride-resistant from wild-type S. mutans. MATERIALS AND METHODS: Cell supernatants from fluoride-resistant and wild-type S. mutans were collected and analyzed by liquid chromatography-mass spectrometry. Principal components analysis and partial least-squares discriminant analysis were performed for the statistical analysis by variable influence on projection (VIP > 2.0) and p value (Mann-Whitney test, p < 0.05). Metabolites were assessed qualitatively using the Human Metabolome Database version 2.0 ( http://www.hmdb.ca ), or Kyoto Encyclopedia of Genes and Genomes ( http://www.kegg.jp ), and Metaboanalyst 6.0 ( https://www.metaboanalyst.ca ). RESULTS: Fourteen metabolites differed significantly between fluoride-resistant and wild-type strains in the early log phase. Among these metabolites, 5 were identified. There were 32 differential metabolites between the two strains in the stationary phase, 13 of which were identified. The pyrimidine metabolism for S. mutans FR was matched with the metabolic pathway. CONCLUSIONS: The fructose-1,6-bisphosphate concentration increased in fluoride-resistant strains under acidic conditions, suggesting enhanced acidogenicity and acid tolerance. This metabolite may be a promising target for elucidating the cariogenic and fluoride resistant mechanisms of S. mutans.

Interplay Between Minerals in Bottled Water and Fluoride Toothpaste and Caries Lesion Remineralization.

OBJECTIVES: he aim of this in vitro study was to evaluate the effects of some bottled waters on fluoride toothpaste efficacy in enhancing caries lesion remineralization. METHODS: Early caries lesions were created in bovine enamel specimens and stratified into treatment groups based on Vickers surface microhardness (VHN). The present study followed a two (fluoride and fluoride-free toothpaste) by five (four bottled waters and tap water) factorial design. The treatment groups were bottled water with the following attributes: (a) 309.9 ppm Ca/1.20 ppm F; (b) 118.4 ppm Ca/0.16 ppm F; (c) 1.00 ppm Ca/1.01 ppm F; and (d) 0.1 ppm Ca/0.04 ppm F and tap water (48.7 ppm Ca/0.7 ppm F). The five water groups were paired either with 1100 ppm fluoride or fluoride-free toothpaste, yielding 10 groups. Specimens were pH-cycled for 10 days with the daily regimen comprised of twice daily toothpaste slurry, with four exposures to water in between. VHN was measured again and the difference was calculated (ΔVHN). Data were analyzed using two-way ANOVA at a 5% significance level. RESULTS: The two-way interaction between water and toothpaste was significant (p<0.001). All groups except fluoride-free toothpaste/bottled water with 0.1 ppm Ca/0.04 ppm F (p=0.411) had significant increases in VHN after pH cycling (p≤0.023). Fluoridated toothpaste resulted in a higher rate of remineralization compared to fluoride-free toothpaste (all p<0.001). Bottled water with 1.20 ppm F/309.9 ppm Ca exhibited the greatest extent of remineralization within fluoride toothpaste groups (p<0.001) and higher remineralization than lower fluoride water in fluoride-free toothpaste groups (p≤0.006). Within the fluoridated toothpaste group, tap water exhibited significantly less remineralization than all bottled waters (all p<0.001). CONCLUSION: Within the limitation of this study, bottled water with higher fluoride and calcium concentrations might improve fluoridated toothpaste efficacy by enhancing remineralization of early enamel caries-like lesions.

Progress in research on the role of fluoride in immune damage.

Excessive fluoride intake from residential environments may affect multiple tissues and organs; however, the specific pathogenic mechanisms are unclear. Researchers have recently focused on the damaging effects of fluoride on the immune system. Damage to immune function seriously affects the quality of life of fluoride-exposed populations and increases the incidence of infections and malignant tumors. Probing the mechanism of damage to immune function caused by fluoride helps identify effective drugs and methods to prevent and treat fluorosis and improve people's living standards in fluorosis-affected areas. Here, the recent literature on the effects of fluoride on the immune system is reviewed, and research on fluoride damage to the immune system is summarized in terms of three perspectives: immune organs, immune cells, and immune-active substances. We reviewed that excessive fluoride can damage immune organs, lead to immune cells dysfunction and interfere with the expression of immune-active substances. This review aimed to provide a potential direction for future fluorosis research from the perspective of fluoride-induced immune function impairment. In order to seek the key regulatory indicators of fluoride on immune homeostasis in the future.

Synthesis of novel magnetic hydroxyapatite-biomass nanocomposite for arsenic and fluoride adsorption.

A magnetic nanocomposite of hydroxyapatite and biomass (HAp-CM) was synthesized through a combined ultrasonic and hydrothermal method, aiming for efficient adsorption of arsenic (As) and fluoride (F-) from drinking water in natural environments. The characterization of HAp-CM was carried out using TG, FTIR, XRD, SEM, SEM-EDS, and TEM techniques, along with the determination of pHpzc charge. FTIR analysis suggested that coordinating links are the main interactions that allow the formation of the nanocomposite. XRD data indicated that the crystalline structure of the constituent materials remained unaffected during the formation of HAp-CM. SEM-EDS analysis revelated a Ca/P molar ratio of 1.78. Adsorption assays conducted in batches demonstrated that As and F- followed a PSO kinetic model. Furthermore, As adsorption fitting well to the Langmuir model, while F- adsorption could be explained by both Langmuir and Freundlich models. The maximum adsorption capacity of HAp-CM was found to be 5.0 mg g-1 for As and 10.2 mg g-1 for F-. The influence of sorbent dosage, pH, and the presence of coexisting species on adsorption capacity was explored. The pH significantly affected the nanocomposite's efficiency in removing both pollutants. The presence of various coexisting species had different effects on F- removal efficiency, while As adsorption efficiency was generally enhanced, except in the case of PO43-. The competitive adsorption between F- and As on HAp-CM was also examined. The achieved results demonstrate that HAp-CM has great potential for use in a natural environment, particularly in groundwater remediation as a preliminary treatment for water consumption.

Mediation of mitochondrial DNA copy number and oxidative stress in fluoride-related bone mineral density alteration in Chinese farmers.

Excessive fluoride can adversely affect bone mineral density (BMD). Oxidative stress and mitochondrial dysfunction are crucial mechanisms of health damage induced by fluoride. Here, a cross-sectional survey involving 907 Chinese farmers (aged 18-60) was carried out in Tongxu County in 2017, aiming to investigate the significance of mitochondrial DNA copy number (mtDNAcn) and oxidative stress in fluoride-related BMD change. Concentrations of urinary fluoride (UF), serum oxidative stress biomarkers, including total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA), as well as relative mtDNAcn in peripheral blood were determined. The multivariable linear model and mediation analysis were performed to assess associations between UF, oxidative stress, and relative mtDNAcn with BMD. Results showed that GSH-Px levels increased by 6.98 U/mL [95% confidence interval (CI) 3.41-10.56)] with each 1.0 mg/L increment of UF. After stratification, the T-AOC, relative mtDNAcn, and BMD decreased by 0.04 mmol/L (-0.08 ~ -0.01), 0.29-unit (-0.55 ~ -0.04), and 0.18-unit (-0.33 ~ -0.03) with every 1.0 mg/L elevation of UF in the excessive fluoride group (EFG, adults with UF > 1.6 mg/L), respectively. Furthermore, T-AOC and relative mtDNAcn were favorably related to the BMD in the EFG (ß = 0.82, 95%CI 0.16-1.48 for T-AOC; ß = 0.11, 95%CI 0.02-0.19 for relative mtDNAcn). Mediation analysis showed that relative mtDNAcn and T-AOC mediated 15.4% and 17.1% of the connection between excessive fluoride and reduced BMD, respectively. Findings suggested that excessive fluoride was related to lower BMD in adults, and the decrement of T-AOC and relative mtDNAcn partially mediate this relationship.

Efficacy of seventh generation bonding agents as desensitizers in patients with dentin hypersensitivity: a randomized clinical trial.

BACKGROUND: Dentin hypersensitivity (DH) is one of the most challenging and persistent dental complaints characterized by transient, intense pain triggered by various stimuli. It affects a significant portion of the global population, predominantly those aged 20-40. This study aims to evaluate the desensitizing efficacy of seventh-generation dentin bonding agents (Single Bond Universal by 3 M ESPE and Xeno-V + by Dentsply) against a control group using Bifluorid 12 by Voco in mitigating DH within a month of the follow-up period. METHODS: This was a single-center, parallel-group, double-blind, controlled randomized clinical trial conducted at Dow University of Health Sciences, Karachi, Pakistan. A total of 105 patients with DH were allocated into three groups for this study. The patients were divided into three groups (Single Bond Universal by 3 M ESPE and Xeno-V + by Dentsply) and the control group containing fluoride varnish (Bifluorid 12 by Voco). Discomfort Interval Scale scores and Schiff Cold Air Sensitivity Scale scores were recorded at baseline, immediately after the intervention, after 01 weeks, and after 01 month. RESULTS: All the materials demonstrated a statistically significant reduction in discomfort and sensitivity (DIS scores p-value 0.01) immediately after 01 week and over a period of 01 month after treatment compared with the baseline scores before application, with no single material proving superior over the one-month observation period. The study also provided insights into dental hygiene practices, with a significant majority using a toothbrush and sensitivity patterns, with cold stimuli being the most common cause of sensitivity. CONCLUSION: The study demonstrates that Single Bond Universal, Xeno V+, and Bifluorid 12 are equally effective in reducing dentin hypersensitivity, with no distinct superiority observed over a one-month period. The findings highlight the potential of fluoride varnishes as a less technique-sensitive and cost-effective option for treating DH, offering valuable insights for future research and clinical practice. TRIAL REGISTRATION: NCT04225247 ( https://clinicaltrials.gov/study/NCT04225247 ), Date of Registration: 13/01/2020. (Retrospectively registered).

Lanthanide Inorganic Nanoparticles Enhance Semiconducting Polymer Nanoparticles Afterglow Luminescence for In Vivo Afterglow/Magnetic Resonance Imaging.

Dual/multimodal imaging strategies are increasingly recognized for their potential to provide comprehensive diagnostic insights in cancer imaging by harnessing complementary data. This study presents an innovative probe that capitalizes on the synergistic benefits of afterglow luminescence and magnetic resonance imaging (MRI), effectively eliminating autofluorescence interference and delivering a superior signal-to-noise ratio. Additionally, it facilitates deep tissue penetration and enables noninvasive imaging. Despite the advantages, only a limited number of probes have demonstrated the capability to simultaneously enhance afterglow luminescence and achieve high-resolution MRI and afterglow imaging. Herein, we introduce a cutting-edge imaging platform based on semiconducting polymer nanoparticles (PFODBT) integrated with NaYF4@NaGdF4 (Y@Gd@PFO-SPNs), which can directly amplify afterglow luminescence and generate MRI and afterglow signals in tumor tissues. The proposed mechanism involves lanthanide nanoparticles producing singlet oxygen (1O2) upon white light irradiation, which subsequently oxidizes PFODBT, thereby intensifying afterglow luminescence. This innovative platform paves the way for the development of high signal-to-background ratio imaging modalities, promising noninvasive diagnostics for cancer.

MiRNA-seq and mRNA-seq revealed the mechanism of fluoride-induced cauda epididymal injury.

The widespread presence of fluoride in water, food, and the environment continues to exacerbate the impact of fluoride on the male reproductive health. However, as a critical component of the male reproductive system, the intrinsic mechanism of fluoride-induced cauda epididymis damage and the role of miRNAs in this process are still unclear. This study established a mouse fluorosis model and employed miRNA and mRNA sequencing; Evans blue staining, Oil Red O staining, TEM, immunofluorescence, western blotting, and other technologies to investigate the mechanism of miRNA in fluoride-induced cauda epididymal damage. The results showed that fluoride exposure increased the fluoride concentration in the hard tissue and cauda epididymis, altered the morphology and ultrastructure of the cauda epididymis, and reduced the motility rate, normal morphology rate, and hypo-osmotic swelling index of the sperm in the cauda epididymis. Furthermore, sequencing results revealed that fluoride exposure resulted in differential expression of 17 miRNAs and 4725 mRNAs, which were primarily enriched in the biological processes of tight junctions, inflammatory response, and lipid metabolism, with miR-742-3p, miR-141-5p, miR-878-3p, and miR-143-5p serving as key regulators. Further verification found that fluoride damaged tight junctions, raised oxidative stress, induced an inflammatory response, increased lipid synthesis, and reduced lipid decomposition and transport in the cauda epididymis. This study provided a theoretical basis for developing miRNA as potential diagnostic markers and therapeutic target drugs for this injury.

An investigation of the corrosion behavior of zinc-coated stainless steel orthodontic wires: the effect of physical vapor deposition method.

BACKGROUND: Releasing of metal ions might implicate in allergic reaction as a negative subsequent of the corrosion of Stainless Steel (SS304) orthodontic wires. The aim of this study was to evaluate the corrosion resistance of zinc-coated (Zn-coated) SS orthodontic wires. METHODS: Zinc coating was applied on SS wires by PVD method. Electrochemical impedance spectroscopy (EIS), Potentiodynamic polarization tests and Tafel analysis methods were used to predict the corrosion behavior of Zn-coated and uncoated SS wires in both neutral and acidic environments. RESULTS: The values of Ecorr ,icorr and Rct ,which were the electrochemical corrosion characteristics, reported better corrosion behavior of Zn-coated SS wires against uncoated ones in both artificial saliva and fluoride-containing environments. Experimental results of the Tafel plot analyses were consistent with that of electrochemical impedance spectroscopy analyses for both biological solutions. CONCLUSION: Applying Zn coating on bare SS orthodontic wire by PVD method might increase the corrosion resistance of the underlying stainless-steel substrate.

Process Intensification for Enhanced Fluoride Removal and Recovery as Calcium Fluoride Using a Fluidized Bed Reactor.

This study explored the feasibility of fluoride removal from simulated semiconductor industry wastewater and its recovery as calcium fluoride using fluidized bed crystallization. The continuous reactor showed the best performance (>90% fluoride removal and >95% crystallization efficiency) at a calcium-to-fluoride ratio of 0.6 within the first 40 days of continuous operation. The resulting particle size increased by more than double during this time, along with a 36% increase in the seed bed height, indicating the deposition of CaF2 onto the silica seed. The SEM-EDX analysis showed the size and shape of the crystals formed, along with the presence of a high amount of Ca-F ions. The purity of the CaF2 crystals was determined to be 91.1% though ICP-OES analysis. Following the continuous experiment, different process improvement strategies were explored. The addition of an excess amount of calcium resulted in the removal of an additional 6% of the fluoride; however, compared to this single-stage process, a two-stage approach was found to be a better strategy to achieve a low effluent concentration of fluoride. The fluoride removal reached 94% with this two-stage approach under the optimum conditions of 4 + 1 h HRT combinations and a [Ca2+]/[F-] ratio of 0.55 and 0.7 for the two reactors, respectively. CFD simulation showed the impact of the inlet diameter, bottom-angle shape, and width-to-height ratio of the reactor on the mixing inside the reactor and the possibility of further improvement in the reactor performance by optimizing the FBR configuration.

Rapid detection of microalgae cells based on upconversion nanoprobes.

The quantification of microalgae cells is crucial for the treatment of ships' ballast water. However, achieving rapid detection of microalgae cells remains a substantial challenge. Here, we develop a new method for rapid and effective detection of microalgae concentration by utilizing upconversion nanoprobes (UCNPs) of NaYF4:Er3+,Tm3+. Three ligands, carboxylated methoxypolyethylene glycols with 5000 and 2000 molecular weights (mPEG-COOH-5, mPEG-COOH-2) and D-gluconic acid sodium salt (DGAS), were used to convert hydrophobic UCNPs into a hydrophilic state through modification. The results show that the mPEG-COOH-5 modified UCNPs present the highest stability in an aqueous solution. Fourier Transform Infrared Spectroscopy (FTIR) measurements reveal the presence of a significant number of -COOH functional groups on UCNPs after the mPEG-COOH-5 modification. These -COOH groups enhance the hydrophilicity and biocompatibility of UCNPs. The soluble UCNPs were directly mixed with microalgae, and the upconversion luminescence (UCL) spectra of the UCNPs were recorded immediately after thorough shaking. This greatly reduces the measurement time and could realize rapid onboard detection. In this sensing procedure, the UCNPs with red UCL functioned as energy donors, while microalgae with red absorption served as an energy acceptor. The UCL gradually diminishes with an increase in microalgae concentration based on the inner filter effect, thus establishing a relationship between UCL and microalgae concentration. The accuracy of the detection is further validated through the traditional microscope counting method. These findings pave the way for a novel rapid strategy to assess microalgae concentration using UCNPs.

Water Fluoridation and Birth Outcomes in California.

BACKGROUND: There is a lack of research on the relationship between water fluoridation and pregnancy outcomes. OBJECTIVES: We assessed whether hypothetical interventions to reduce fluoride levels would improve birth outcomes in California. METHODS: We linked California birth records from 2000 to 2018 to annual average fluoride levels by community water system. Fluoride levels were collected from consumer confidence reports using publicly available data and public record requests. We estimated the effects of a hypothetical intervention reducing water fluoride levels to 0.7 ppm (the current level recommended by the US Department of Health and Human Services) and 0.5 ppm (below the current recommendation) on birth weight, birth-weight-for-gestational age z-scores, gestational age, preterm birth, small-for-gestational age, large-for-gestational age, and macrosomia using linear regression with natural cubic splines and G-computation. Inference was calculated using a clustered bootstrap with Wald-type confidence intervals. We evaluated race/ethnicity, health insurance type, fetal sex, and arsenic levels as potential effect modifiers. RESULTS: Fluoride levels ranged from 0 to 2.5 ppm, with a median of 0.51 ppm. There was a small negative association on birth weight with the hypothetical intervention to reduce fluoride levels to 0.7 ppm [-2.2g; 95% confidence interval (CI): -4.4, 0.0] and to 0.5 ppm (-5.8g; 95% CI: -10.0, -1.6). There were small negative associations with birth-weight-for-gestational-age z-scores for both hypothetical interventions (0.7 ppm: -0.004; 95% CI: -0.007, 0.000 and 0.5 ppm: -0.006; 95% CI: -0.013, 0.000). We also observed small negative associations for risk of large-for-gestational age for both the hypothetical interventions to 0.7 ppm [risk difference (RD)=-0.001; 95% CI: -0.002, 0.000 and 0.5 ppm (-0.001; 95% CI: -0.003, 0.000)]. We did not observe any associations with preterm birth or with being small for gestational age for either hypothetical intervention. We did not observe any associations with risk of preterm birth or small-for-gestational age for either hypothetical intervention. CONCLUSION: We estimated that a reduction in water fluoride levels would modestly decrease birth weight and birth-weight-for-gestational-age z-scores in California. https://doi.org/10.1289/EHP13732.

Mineralization of SF6 and NF3 fluorinated compounds for greenhouse gas abatement by oxalates.

Fluorinated compounds (FCs) such as sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3) have garnered attention due to their environmental impact. This study investigates the mineralization and removal of two potent FCs: SF6 and NF3. The results confirm that utilizing various oxalate salts leads to the formation of corresponding metallic fluorides: lithium fluoride (LiF), sodium fluoride (NaF), and potassium fluoride (KF), validating the occurrence of mineralization reactions. Among the oxalate salts, sodium oxalate demonstrates the highest mineralization efficiency in both SF6 and NF3 removal. Real-time Fourier transform infrared spectroscopy (FT-IR) gas-phase analysis confirms rapid and complete gas removal within a short reaction time using the selected oxalate salts. Meticulous mass balance calculations revealed that oxalates (LiF, NaF, and KF) yielded sulfur (S) at rates of 92.09%, 91.85%, and 84.98% following SF6 mineralization. Additionally, the conversion rates of oxalates to the corresponding metallic fluorides (LiF, NaF, and KF) after SF6 mineralization were 98.18%, 95.82%, and 95.21%, respectively. Similarly, after NF3 mineralization, these conversion rates stood at 92.18%, 90.67%, and 90.02%, respectively. The removal efficiencies for SF6 (1000 ppm) were 4.98, 12.01, and 7.23 L/g, while those for NF3 (1000 ppm) were 14.1, 12.6, and 11.7 L/g, respectively. Notably, sodium oxalate exhibits superior effectiveness, achieving 100% SF6 conversion within 30 min and 100% NF3 conversion within 50 min. This work underscores the potential of oxalate mineralization as a promising strategy for efficient and rapid removal of potent fluorinated compounds, paving the way for environmentally benign FC remediation techniques with broader implications for sustainable gas treatment technologies.

Changes in Metabolism and Content of Chlorophyll in Common Duckweed (Lemna minor L.) Caused by Environmental Contamination with Fluorides.

The impact of fluorine on plants remains poorly understood. We examined duckweed growth in extracts of soil contaminated with fluorine leached from chicken manure. Additionally, fluorine levels were analyzed in fresh manure, outdoor-stored manure, and soil samples at varying distances from the manure pile. Fresh manure contained 37-48 mg F- × kg-1, while soil extracts contained 2.1 to 4.9 mg F- × kg-1. We evaluated the physiological effects of fluorine on duckweed cultured on soil extracts or in 50% Murashige-Skoog (MS) medium supplemented with fluorine concentrations matching those in soil samples (2.1 to 4.9 mg F- × L-1), as well as at 0, 4, and 210 mg × L-1. Duckweed exposed to fluorine displayed similar toxicity symptoms whether in soil extracts or supplemented medium. Fluoride at concentrations of 2.1 to 4.9 mg F- × L-1 reduced the intact chlorophyll content, binding the porphyrin ring at position 32 without affecting Mg2+. This reaction resulted in chlorophyll a absorption peak shifted towards shorter wavelengths and formation of a new band of the F--chlorophyll a complex at λ = 421 nm. Moreover, plants exposed to low concentrations of fluorine exhibited increased activities of aminolevulinic acid dehydratase and chlorophyllase, whereas the activities of both enzymes sharply declined when the fluoride concentration exceeded 4.9 mg × L-1. Consequently, fluorine damages chlorophyll a, disrupts the activity of chlorophyll-metabolizing enzymes, and diminishes the plant growth rate, even when the effects of these disruptions are too subtle to be discerned by the naked human eye.

Investigating the Mechanism of Aluminum Fluoride Chelation.

Aluminum fluoride (AlF) complexes have been used over the past decade to incorporate [18F]fluoride into large biomolecules in a highly selective fashion by using relatively facile conditions. However, despite their widespread usage, there are a large number of variations in the reaction conditions, without a definitive discussion provided on the mechanism to understand how these changes would alter the end result. Herein, we report a detailed mechanistic investigation of the reaction, using a mixture of theoretical studies, fluorine-19 and fluorine-18 chemistry, and the consequences it has on the efficient clinical translation of AlF-containing imaging agents.

The fluoride exporter (CsFEX) regulates fluoride uptake/accumulation in Camellia sinensis under different pH.

Fluoride (F) can be absorbed from the environment and hyperaccumulate in leaves of Camellia sinensis without exhibiting any toxic symptoms. Fluoride exporter in C. sinensis (CsFEX) could transport F to extracellular environment to alleviate F accumulation and F toxicity, but its functional mechanism remains unclear. Here, combining with pH condition of C. sinensis growth, the characteristics of CsFEX and mechanism of F detoxification were further explored. The results showed that F accumulation was influenced by various pH, and pH 4.5 and 6.5 had a greater impact on the F accumulation of C. sinensis. Through Non-invasive Micro-test Technology (NMT) detection, it was found that F uptake/accumulation of C. sinensis and Arabidopsis thaliana might be affected by pH through changing the transmembrane electrochemical proton gradient of roots. Furthermore, diverse expression patterns of CsFEX were induced by F treatment under different pH, which was basically up-regulated in response to high F accumulation, indicating that CsFEX was likely to participate in the process of F accumulation in C. sinensis and this process might be regulated by pH. Additionally, CsFEX functioned in the mitigation of F sensitivity and accumulation strengthened by lower pH in Escherichia coli and A. thaliana. Moreover, the changes of H+ flux and potential gradient caused by F were relieved as well in transgenic lines, also suggesting that CsFEX might play an important role in the process of F accumulation. Above all, F uptake/accumulation were alleviated in E. coli and A. thaliana by CsFEX through exporting F-, especially at lower pH, implying that CsFEX might regulate F accumulation in C. sinensis.

Groundwater vulnerability to fluoride pollution and health risk assessment in the western part of Odisha, India.

The fluoride dynamics of the Dharmagarh Block of Kalahandi District, Odisha, India, and associated health risk assessment have been studied. Complex data matrices were evaluated using groundwater quality index, fluoride pollution index, and principal component analysis to understand the geological evolution and identify potential sources for fluoride pollution. The study region comprises granite, granitic gneiss, and khondalite of hard and compact rock of Precambrian Eon, which supplies mostly the fluoride-bearing minerals. Altogether thirty-four (34) groundwater samples across the entire study area were collected and subjected to various physico-chemical analyses. The majority of the groundwater in the proposed region is hard to very hard type with Mg-HCO3 and Na-HCO3 being the two dominant facies. Groundwater contains fluoride in concentrations ranging from 0.21 to 2.26 mg/L. The statistical analysis of the quality parameters reveals the moderate positive correlation of fluoride with sodium (0.392) and pH (0.313) and week positive correlation with EC, TDS, TH, TA, Mg2+, and HCO3-, which directly depicts the initiation of fluoride problem within the study area. Based on the water quality index, 23.53% samples are good, 73.53% are poor, and 2.94% are very poor in nature. With respect to fluoride pollution index, 5.88% samples show high pollution, 55.88% samples show medium pollution, and 38.24% of samples show low pollution index. Human health risk assessment has also been carried out using the hazard quotient of fluoride. Altogether 70.59% of samples show Total Hazard Index (THI) values < 1 suggesting low risk of cancer and within the permissible range, whereas 29.41% of samples show THI > 1 suggesting the non-carcinogenic risk of pollutants, which exceeds the allowable limit for all the classes of male, female and children.

A V-shaped bis-coumarin based fluorescence probe for F- detection in tea infusions and potable water and bioimaging applications in living systems.

Fluorine (F) is a pivotal element in the formation of human dental and skeletal tissues, and the consumption of water and tea constitutes a significant source of fluoride intake. However, prolonged ingestion of water and tea with excessive fluoride content can lead to fluorosis, which poses a serious health hazard. In this manuscript, a novel turn-on fluorescent probe DCF synthesized by bis-coumarin and tert-butyldiphenylsilane (TBDPS) was introduced for detecting F- in potable water and tea infusions. By leveraging the unique chemical affinity between fluoride and silicon, F- triggers the silicon-oxygen bond cleavage in DCF, culminating in a conspicuous emission of yellow fluorescence. Validated through a succession of optical tests, this probe exhibits remarkable advantages in terms of superior selectivity, a low detection limit, a large Stokes shift, and robust interference resistance when detecting inorganic fluoride. Moreover, it can serve as portable test strips for on-site real-time identification and quantitative analysis of F-. Furthermore, the application of DCF for in-situ monitoring and imaging of F- in zebrafish and soybean root tissues proved its significant value for F- detection in both animal and plant systems. This probe potentially functions as an efficient instrument for delving into the toxic mechanisms of fluoride in physiological processes.