Search

The CF2H group can act as a hydrogen bond donor, serving as a potential surrogate for OH or SH groups but with a weaker hydrogen bond donation ability. Here, we describe a series of CF2H group-containing moieties that facilitate hydrogen bond interactions. We survey hydrogen bond donation ability using several established methods, including 1H NMR-based hydrogen bond acidity determination, UV–vis spectroscopy titration with Reichardt's dye, and 1H NMR titration using tri-n-butylphosphine oxide as a hydrogen bond acceptor. Our experiments reveal that the direct attachment of the CF2H group to cationic aromatic systems significantly enhances its hydrogen bond donation ability, a result consistent with theoretical calculations. We anticipate that this chemistry will be valuable for designing functional molecules for chemical biology and medicinal chemistry applications.

Abstract Chemically engineered extracts represent a promising source of new bioactive semi-synthetic molecules. Prepared through direct derivatization of natural extracts, they can include constituents enriched with elements and sub-structures that are less common in natural products compared to drugs. Fourteen such extracts were prepared through sequential reactions with hydrazine and a fluorinating reagent, and their α-glucosidase inhibition properties were compared. For the most bioactive mixture, a chemically modified propolis extract, enzyme inhibition increased 22 times due to the reaction sequence. Bio-guided fractionation led to the isolation of a new fluorinated pyrazole produced within the extract by chemical transformation of the flavonoid chrysin. The inhibitor results from the action of the two reagents used on four common functional groups present in natural products (carbonyl, phenol, aromatic carbon, and a double bond). The reactions led to the opening of a 6-member oxygenated heterocycle to produce a 5-member nitrogenated one, as well as the dehydroxylation and fluorination in two different positions of one of the aromatic rings of the natural starting material, all within a complex mixture of natural products. Overall, these transformations led to an approximately 20-fold increase in the α-glucosidase inhibition by the isolated inhibitor compared to its natural precursor. Graphical Abstract

Abstract Background Colorectal cancer (CRC) is a globally prevalent malignancy, primarily affecting the colon and rectum, characterized by uncontrolled cellular changes in the intestinal wall lining. Recent evidence underlines the significant role of the CXCL12/CXCR4 axis in the development of CRC, suggesting that inhibiting this pathway could be a promising therapeutic approach. This study focuses on investigating the potential of N, N''-thiocarbonylbis (N'-(3,4-dimethyl phenyl)-2,2,2-trifluoroacetimidamide) (A1), a novel fluorinated CXCR4 inhibitor, through a comprehensive analysis encompassing in silico, in vitro, and in vivo studies. Methods The molecular dynamic simulation method was employed to compute A1 binding affinity and energy for the CXCR4 receptor compared to AMD3100. In vitro experiments utilized the CT-26 mouse CRC cell line to compare the inhibitory effects of A1 and AMD3100 on tumor cell proliferation and migration. Following the development of the CRC animal model in BALB/c mice, immune system responses within the tumor microenvironment (TME) were evaluated. Flow cytometry and real-time PCR (RT-PCR) were used to measure the effects of AMD3100 and A1 on regulatory T-cell (Treg) infiltration and the expression of CXCR4, vascular endothelial growth factor (VEGF), fibroblast growth factors (FGF), interleukin-10 (IL-10), and tumor growth factor-beta (TGF-β) genes in tumor tissue. Additionally, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) techniques were employed to assess VEGF, IL-10, and TGF-β tissue levels at the protein level. Results Molecular dynamic simulation studies with molecular mechanics Poisson-Boltsman surface area (MM-PBSA) analysis revealed that A1 exhibits significantly lower binding energy for the CXCR4 receptor than AMD3100. A1 effectively inhibited the proliferation of CT-26 cells, significantly reduced tumor cell migration, attenuated Treg infiltration, and suppressed IL-10 and TGF-β expression at both mRNA and protein levels in vivo. Notably, A1 outperformed AMD3100 in reducing tumor size and increasing survival rate in treated animals, with minimal side effects. Conclusion These findings emphasize the potential of A1 as a favorable anti-tumor small molecule in CRC. Further validation through rigorous preclinical and clinical studies may position A1 as a promising alternative to AMD3100 in human cancers.

The article presents the results of the study of the effect of fluoride on the morphometric and physiological parameters of higher plants. The test culture was the seeds of oat Avena sativa L. Phytotesting was carried out according to standard methods in eluate and contact versions. Four different levels (0.09, 0.9, 9 and 90 mgF/L) of NaF solution for eluate phytotesting and five levels (10, 100, 500, 1000 and 2000 mgF⸱kg−1 dry soil) for contact phytotesting were applied. The decrease in root length, plant height and biomass at the maximum pollution level (90 mgF/L and 2000 mgF⸱kg−1 dry soil, respectively) relative to the control was 35.5, 23.86 and 62.47%, respectively. Statistical data processing was conducted. In addition, using a portable mini-spectrometer for leaves CI-710S, indices characterizing changes in chlorophyll content in plants were determined: Chlorophyll Content Index, Green Chlorophyll Index, Red-Edge Chlorophyll Index, Leaf Chlorophyll Index, Soil–Plant Analysis Development. The decrease in CCI, CI Green, CI Red, LCI, and SPAD indices at the maximum pollution level (2000 mgF⸱kg−1 dry soil) relative to the control was 86.2, 42.0, 57.9, 32.8 and 70.4%, respectively. Correlation analysis using the Pearson coefficient made it possible to establish a significant relationship between individual morphometric and physiological indicators. It was found that high levels of soil fluoride contamination cause significant changes in the morphometric and physiological parameters of Avena sativa L. The results of the study may have implications for agriculture or environmental protection in areas exposed to fluoride.

The gram-scale synthesis of 6,6-difluorobicyclo[3.2.0]heptane-derived building blocks (i.e., primary amine and carboxylic acid) was performed via the deoxofluorination of the corresponding bicyclic keto ester with diethylaminosulfur trifluride (DAST). Physicochemical properties of the compounds obtained (i.e., pKa) or their model benzamide / anilide derivatives (i.e., LogP) were determined experimentally and compared to those of monocyclic and non-fluorinated bicyclic counterparts. It was found that gem-difluorination expectedly decreased the pKa values by 0.3 - 0.5 units, whereas the LogP values were decreased by 0.54 - 0.55 units. Meanwhile, the bicyclic system itself had a negligible impact on the compounds’ acidity and lipophilicity compared to the monocyclic counterparts.

Dysobinin is a naturally occurred limonoid, which is a specific form of triterpenoid, mostly found in certain plants, particularly the Meliaceae family. Overall, it has been found that limonoids have a wide range of biological functions. Typically, the compound comprises anticancer, antimicrobial, and anti-inflammatory properties. Even though dysobinin has shown some effectiveness, its potential in pharmacology, so far, is found limited. This study, therefore, aims to enhance the pharmacological properties of dysobinin through the addition of fluorine. To do this, a one-pot, two-step reaction comprising C-H borylation and selectfluor was used to turn dysobinin into two new compounds: 1,2-dihydro-6?-acetoxyazadirone (5) and 1?-fluorodysobinin (6). After the transformation, various spectroscopic methods, including UV (Ultraviolet), IR (infrared), MS (mass spectra), as well as NMR (1D and 2D) were applied to figure out the structures of the new compounds. Accordingly, of the derived compounds, 1?-fluorodysobinin showed significantly higher cytotoxicity against A549 lung cancer cells when compared to dysobinin.

The development of emerging fluorinated groups is an active field of research in recent years. In particular, the fusion of fluorinated moieties with chalcogens has attracted considerable interest. This has led to a strong demand for the development of new efficient reagents to perform various direct trifluoromethylchalcogenations. Herein, we present an overview of the results obtained in our laboratory in Lyon, which has actively contributed to this quest during the last 15 years.

Thanks to their ability to absorb large amounts of trace elements from the atmosphere, lichens are widely used as bioaccumulators and bioindicators of air pollution. Among air pollutants, heavy metals represented by lead are the most important contributors to the deterioration of ecosystems. Fluorine is prevalent in a wide range of environmental matrices, even in trace amounts, and is one of the most phytotoxic halogens to plants. When lichens are exposed to air pollution, they frequently undergo structural, morphological and physiological alterations, and exhibit several coping strategies to combat and tolerate stressful situations. This manuscript presents general information about lichens, fluorine, and lead as well as the toxic effect of these two air pollutants on lichens, and the means of combat used by lichens to respond to fluorine and lead-induced stress.

Two racemic anti-4,6-diphenyl-5,5-difluoro-1,3-dioxanes were prepared and the corresponding enantiomers were evaluated as potential new chiral dopants for liquid-crystal compositions.

Trifluoromethoxylated molecules and selenylated compounds find a wide range of interesting applications, but separately. In order to combine the potential of these two motifs and to propose a new class of compounds, we have developed an electrophilic phenylseleno trifluoromethoxylation of alkenes, which leads to β-selenylated trifluoromethoxylated compounds or, upon subsequent reduction, to the trifluoromethoxylated ones.

We describe herein a facile method to access 2,3-epoxyesters with fluorine-containing substituents at their 3-position starting from the corresponding enoates by utilization of the low-costed and easy-to-handle reagent, NaOCl·5H2O. Because very little has been disclosed about the reactivity of such 2,3-epoxyesters, their epoxy ring opening by a variety of nucleophiles was carried out and we succeeded in clarifying these chemo- as well as regioselective processes proceeding via the SN2 mechanism to mainly afford 2-substituted 3-hydroxyesters usually in a highly anti selective manner.

Objective: To evaluate the effect of an educational comic book on indirectly supervised tooth brushing practices in early childhood education. Material and Methods: This is a quantitative action research aimed at evaluating the effect of a comic book on the necessary knowledge for indirectly supervised tooth brushing practices in early childhood education. Thirty-eight teachers from three daycare centers in the city of Porto Real, Brazil, participated in the year 2021, being carried out in three stages: 1: teachers answered a questionnaire for the identification of their sociodemographic and professional profile, in addition to prior knowledge about oral health. They also sent a photo of the toothbrush after applying the amount of toothpaste they used during the indirect supervised tooth brushing at the daycare center; 2: reception and 30 days to read the comic book; 3: answer to a new instrument on knowledge about oral health. Sending a new photo of the toothbrush with the toothpaste. Results: The amount of paste applied to toothbrushes decreased after reading the comic book from 58.1% to 27.8% of tufts, on average (p

Tea plant can enrich a large amount of fluorine (F) in the cell wall of its mature leaves, thus posing the risk of excessive intake of F for tea consumers. This study investigated the effect of foliar calcium (Ca) application (0.05-1 mM) on F accumulation in tea plant leaves by analyzing the association of F with cell wall materials, pectin methylesterification structure, and cell wall genes. Ca spray could effectively reduce the F level, the content of wall carbohydrates (excluding the chelate pectin fraction) and the pectin methylesterification degree in tea plant leaves. Correlation analysis further revealed that the tea leaf F content was positively correlated with most of the cell wall materials. Transcriptomics analysis indicated that the key genes involved in reorganization of cell wall polysaccharides (such as CslE6, XTH32, PG, PGIP, PME18, PMEU1, and PMEI9) were associated with the variations in F content and cell wall components. All the results suggest that Ca may lessen the tea leaf F level by reducing the accumulation of cell wall materials and intervening the cell wall structure and gene expression. This study provided useful information for reducing the F level and solving the F safety problem in tea plant.

In investigating sustainable methodologies for removing recalcitrant organic pollutants from wastewater, visible-light-responsive photocatalysis has drawn considerable interest. Therefore, intentionally engineered photocatalysts with enhanced solar-light-absorption capacity and boosted charge carrier’s separation are highly demanded. In the present attempt, pure cobalt ferrite (CoFe2O4) and its fluorine-doped counterpart (F-CoFe2O4) were fabricated via co-precipitation. The fluorine-doped material was integrated into the 2D MXene to design the composite (F-CoFe2O4@MXene) by the ultrasonication method. The structure, surface morphology, chemical composition, and optical properties of the as-prepared catalysts were characterized by various techniques, including powder XRD, FTIR, SEM, EDS, UV–vis absorption, and photoluminescence spectroscopy. The photocatalytic potential was estimated by degrading crystal violet (CV) dye and benzoic acid (BA), which were selected as model pollutants. The composite material showcases significantly enhanced catalytic efficiency relative to the pure and doped materials. Under solar light exposure for 140 min, 91 % (0.0138 min−1) and 87 % (0.0133 min−1) of CV and BA degradation were achieved, respectively. The remarkable catalytic potential of the composite material corresponds to the fluorine doping and integration to the 2D MXene, which has enhanced its visible-light absorption and lowered the rapid recombination rate of the separated charges (e-/h+). Systematic studies, including reaction kinetics, dominating catalytic species in photodegradation, and stability of the catalyst, were followed through to disclose the photocatalytic potential of the designed F-CoFe2O4@MXene. Furthermore, the real-time applicability of the catalyst has been explored.

The efficiency of hydrogen negative ion production in negative ion sources depends on the work function of the molybdenum surface. Deposition of cesium (Cs) atoms on the Mo surface reduces the work function from over 4.0 eV to about 1.50–1.80 eV. However, the Fermi level remains below the affinity level (−0.75 eV) of hydrogen negative ions. To explore further reduction methods, the work function of Cs co-adsorbed with fluorine on the Mo (001) surface was studied using DFT calculations. The results show that at 4/16 θ Cs coverage, adding fluorine can reduce the work function, achieving the lowest value of 1.40 eV at 8/16 θ F coverage. Analysis reveals a significant vacuum-inward dipole moment with fluorine-Cs co-adsorption, favorably reducing the work function. However, fluorine’s strong electronegativity also creates a surface-directed dipole moment, increasing the work function. Introducing fluorine is beneficial only at 4/16 θ Cs coverage, indicating that precise control of Cs coverage is necessary to achieve lower work functions.

The introduction of fluorine in compounds plays a crucial role in drug development as it greatly influences their final pharmacokinetic and dynamic properties. Due to the prevalence of fluorine in FDA-approved drugs in recent years, identifying the mechanisms driving their chemical transformations has become crucial in the drug discovery landscape. 19F NMR spectroscopy is a powerful analytical technique that allows for the examination of fluorine-containing compounds, offering valuable information about their structure, dynamics, and reactivity. NMR spectra can be interpreted through the leveraging of Density Functional Theory (DFT). However, the screening of compounds and discovery of feasible drug candidates is limited due to its computational cost. Here, we present a machine learning approach to accelerate the prediction of DFT-calculated 19F NMR chemical shifts. The fluorine atoms’ features in the models were derived from their local three-dimensional environments, representing their neighboring atoms within a radius of n Å away from the given fluorine atom in the compound. A comparative analysis of thirteen regression models was conducted using features extracted from 501 fluorinated compounds in our laboratory’s chemical inventory. Among the models, Gradient Boosting Regression (GBR) exhibited the highest performance, achieving a mean absolute error of 3.31 ppm with a local environment radius of 3 Å. This demonstrates a comparable accuracy to DFT calculations while reducing computational time from several hundred seconds to milliseconds. 3 Å was also found to be the most optimal radius across all models when encoding features for local atomic environments.

The aluminium smelter in Žiar nad Hronom has operated since 1953. As a result, the surrounding area is now one of the most polluted regions in Slovakia. Since the implementation of new production and filtration technologies in 1996, the amount of emissions has significantly decreased. Our aim was to evaluate the long-term restoration of an environment that has been damaged by fluorine-based air pollutants. We analysed the contamination of forest ecosystems in three beech stands at various distances from the emission source (2, 7, and 18 km). Signs of restoration in adult beech trees were observed through a decrease in defoliation and a reduction in the necrotic disease of the bark in tree crowns. However, the impacts of air pollution on ectomycorrhizal associations persist. In the reduced number of ectomycorrhizal fungal species (16 species in the polluted stand compared to 38 species in the control stand), the low representation of sensitive fungal orders (Cantharellales, Gomphales, and Boletales), and the indices of species richness and heterogeneity (Hill, Margalef, Simpson, and Shannon–Weaver). In some respects, the findings indicate that the beech ecosystem is capable of revitalization within 25 years after a reduction in air pollution. However, much more sensitive indicators of successful restoration, compared to the characteristics of the trees, are the communities of macromycetes.

Abstract Settling the structure stacking of graphene (G) nanosheets to maintain the high dispersity has been an intense issue to facilitate their practical application in the microelectronics‐related devices. Herein, the co‐doping of the highest electronegative fluorine (F) and large atomic radius chlorine (Cl) into G via a one‐step electrochemical exfoliation protocol is engineered to actualize the ultralong cycling stability for flexible micro‐supercapacitors (MSCs). Density functional theoretical calculations unveiled that the F into G can form the “ionic” C─F bond to increase the repulsive force between nanosheets, and the introduction of Cl can enlarge the layer spacing of G as well as increase active sites by accumulating the charge on pore defects. The co‐doping of F and Cl generates the strong synergy to achieve high reversible capacitance and sturdy structure stability for G. The as‐constructed aqueous gel‐based MSC exhibited the superb cycling stability for 500,000 cycles with no capacitance loss and structure stacking. Furthermore, the ionic liquid gel‐based MSC demonstrated a high energy density of 113.9 mW h cm−3 under high voltage of up to 3.5 V. The current work enlightens deep insights into the design and scalable preparation of high‐performance co‐doped G electrode candidate in the field of flexible microelectronics.

Fluorine (F) and Cadmium (Cd) have given rise to public concern regarding their adverse impacts on the environment and human beings. Yet, the toxic interplay between F and Cd on the intestine is still vague. Aiming to investigate the role of F on Cd-damaged intestine, a total of five groups of 30 SD rats were picked at random to be gavaged for 90 days: Control group (Ultra-pure water), Cd (Cd 1 mg/kg), Cd+LF (Cd 1 mg/kg+F 15 mg/kg), Cd+MF (Cd 1 mg/kg+F 45 mg/kg), and Cd+HF (Cd 1 mg/kg+F 75 mg/kg). It demonstrated that Cd enriched in the intestine and disordered intestinal barrier of rats. Interestingly, two side effects of F were observed resisting to the Cd toxicity. The Cd levels in colon contents were attenuated by 45.45 %, 28.11 %, and 19.54 % by F supplement, respectively. In the Cd+LF group, SOD, GSH-Px, and CAT activities elevated by 0.93, 1.76, and 1.78 times, respectively, and the MDA content reduced 0.67 times; the expressions of NQO1, SOD2, and GSH-Px mRNA markedly enhanced, as well as the Keap1 mRNA significantly decreased. Nevertheless, all indexes above in the Cd+HF group showed the opposite trends. Furthermore, LPS levels decreased by 45.93 % for the Cd+LF group and increased by 12.70 % in that the Cd+HF group. The ZO-1 expression in the Cd+LF group increased, whereas the Cd+HF group's expressions of Claudin-1, Occludin, and ZO-1 were all diminished by 35.46 %, 27.23 %, and 16.32 %, respectively. Moreover, the levels of TNF-α, IL-1β and TLR-4 decreased and IL-10 level promoted, while all showed opposite trends in the Cd+HF group. Collectively, it indicated there is a twofold interplay between F and Cd on intestinal damage and mainly depends on F dosages.

In order to find new potential fungicides and anticancer agents, a series of new coumarin amide derivatives bearing fluorine were synthesized and characterized spectroscopically. Compounds A6, B11, C2 and C7 were confirmed by X-ray diffraction further. The antifungal bioassays against five typical pathogenic fungi showed that compound C5 exhibited more remarkable fungicidal activities against Alternaria alternata (EC50 = 11.5 μg/mL), Colletotrichum gloeosporioides (EC50 = 18.0 μg/mL), Pyricularia grisea (EC50 = 33.8 μg/mL), surpassing kresoxim-methyl. Molecular docking result indicated that C5 displayed high binding affinity to chitinase, which plays crucial role in degradation and remodeling of fungal cell walls. In addition, the anticancer bioassays against three cancer cells demonstrated that compound A4 displayed excellent growth inhibitory effect against Hela cells with IC50 value of 8.13 μM, and low cytotoxicity against human normal cells BEAS-2B. Flow cytometric analysis further demonstrated that A4 significantly arrested cell cycle at the S phase and trigger apoptosis. With the above interesting biological profile, these coumarin derivatives could be used as anfungicides and anticancer candidates.

In the title compound, C21H27BF2N2O4, a highly fluorescent boron–dipyrromethene dye, the methylpropionate moieties have different conformations. In the crystal, weak C—H...F and C—H...O interactions link the molecules. Some optical properties are presented.

Objective Yishu fault zone geothermal field and central Shandong uplift geothermal field are typical geothermal fields in south central Shandong Province. In order to investigated the distribution characteristics and mechanisms of fluorine enrichment in the geothermal water of the this area, Methods hydrochemical diagrams, geochemical simulations and principal component analysis were employed. Results The results show that the geothermal water in the study area is mainly Na-Ca-Cl-, Na-Ca-SO4-Cl- and Na-Cl-SO4-type water, dominated by weakly alkaline water. The predominant cation is the sodium ion, with fluorine concentration between 0.38 and 4.5 mg/L. Sodium-rich and weakly alkaline environments are faciliated to the enrichment of fluorine in the geothermal water. The fluorine concentration has significant positive correlations with the Na+, Cl- and TDS concentrations in the geothermal water. In addition, it has significant positive correlations with K+ and SO42- concentrations and significant negative correlations with Mg2+ and HCO3- concentrations in the geothermal water in the Yishu fault zone. The cation exchange effect in the geothermal water of the central Shandong uplift zone is stronger than that in the Yishu fault zone, and the reaction strength of Na+ is significantly stronger than that of Mg2+. The geothermal field of the central Shandong uplift and Yishu fault zones are both fracturing types. The thermal storage lithologies are limestone, limestone in the thermal alteration zone and ansanite in the broken belt, with strong water-rock interactions. The provenance of fluorine in the geothermal water is the dissolution reprecipitation of fluorine-containing minerals, and the fluorine concentration in the geothermal water is further increased by cation exchange and other water-rock interactions. High temperature and sodium-rich have a great influence on fluorine enrichment. Conclusion This research provides a reference for the exploitation and utilization of geothermal resources.

The impact of varying F content from 4 wt% to 10 wt% on the structure and properties of non-reactive mold slag for high-Mn high-Al steel was investigated in this study. Employing a combination of techniques including a rotary viscometer, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Raman spectroscopy, the viscosity and structure of mold slag were analyzed. The findings revealed that increasing F content led to a gradual reduction in viscosity, activation energy for viscous flow, and the internal friction within the mold fluxes, consequently enhancing its fluidity. The Al–O–Al structure remained stable throughout the experimental range. The decrease in QAl2 content indicated a continuous depolymerization process, leading to the formation of free [Al2OF6] and [AlO6] structures as F content increased. At the same time, the replaced O2− ions were assimilated by [AlO4] tetrahedron, facilitating the formation [AlO6] octahedron. Consequently, the slag structure was simplified, resulting in a reduction in the degree of polymerization and viscosity.

The pH of Mount Ijen crater water is 0-2, resulting in water that is acidic and sulfurous. A fault near the Mount Ijen Crater causes seepage so that acidic water flows into the Banyupait River. Chemical elements and heavy metals originating from the river pollute groundwater and plants. As a result, people around the river consume heavy metals. This research aims to determine the quality of river water and groundwater, as well as determine community factors that are susceptible to dental fluorosis. The methodology used is field mapping and laboratory analysis. For water samples, the Atomic Absorption Spectrophotometer (AAS) method is used. The pH of river water at the research location exceeds the quality standard, namely pH 4-5.5. Meanwhile, groundwater fluorine and sulfate elements exceed quality standards, namely fluorine of 0.6171 mg/L and 0.6870 mg/L, and sulfate ranging from 325-683 mg/L. These two elements cause symptoms of dental fluorosis. Meanwhile, the community factors most susceptible to dental fluorosis are people in the adult age category, and the last level of education is elementary school. This is because the Banyupait River water and groundwater are exposed to fluorine and sulfate water originating from seepage from the Mount Ijen Crater. HIGHLIGHTS Mount Ijen crater water exhibits extreme acidity, containing sulfurous compounds, leading to the acidification of the Banyupait River.; Pollution of groundwater and plants occurs at the Banyupait River, posing health risks to nearby communities.; Groundwater quality parameters, notably fluorine and sulfate levels are identified as contributors to dental fluorosis symptoms.;

A carboranylporphyrin of A3B-type bearing a single pentafluorophenyl ring was prepared through the regioselective nucleophilic aromatic substitution reaction of the p-fluorine atoms in 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with 9-mercapto-m-carborane. The reaction of this porphyrin with sodium azide led to the selective substitution of the p-fluorine atom in the pentafluorophenyl substituent with an azide functionality which upon reduction with SnCl2 resulted in the formation of the corresponding porphyrin with an amino group. Pentafluorophenyl-substituted A3B-porphyrins were studied and transformed to thiol and amino-substituted compounds allowing for the preparation of porphyrins with different reactive groups such as hydroxy and amino derivatives capable for further functionalization and conjugation of these porphyrins to other substrates. In addition, conjugates containing maleimide or biotin entities in the structure of carborane A3B-porphyrin were also synthesized based on the amino-substituted A3B-porphyrin. The structures of the prepared carboranylporphyrins were determined by UV–vis, IR, 1H, 19F, 11B NMR spectroscopic data and MALDI mass spectrometry.

Abstract Immune checkpoint inhibitor (ICI)-derived evolution offers a versatile means of developing novel immunotherapies that targets programmed death-ligand 1 (PD-L1)/programmed death-1 (PD-1) axis. However, one major challenge is T cell exhaustion, which contributes to low response rates in "cold" tumors. Herein, we introduce a fluorinated assembly system of LFNPs/siTOX complexes consisting of fluorinated EGCG (FEGCG), fluorinated aminolauric acid (LA), and fluorinated polyethylene glycol (PEG) to efficiently deliver small interfering RNA anti-TOX (thymus high mobility group box protein, TOX) for synergistic tumor cells and exhausted T cells regulation. Using a microfluidic approach, a library of LFNPs/siTOX complexes were prepared by altering the placement of the hydrophobe (LA), the surface PEGylation density, and the siTOX ratio. Among the different formulations tested, the lead formulation, LFNPs3-3/siTOX complexes, demonstrated enhanced siRNA complexation, sensitive drug release, improved stability and delivery efficacy, and acceptable biosafety. Upon administration by the intravenous injection, this formulation was able to evoke a robust immune response by inhibiting PD-L1 expression and mitigating T cell exhaustion. Overall, this study provides valuable insights into the fluorinated assembly and concomitant optimization of the EGCG-based delivery system. Furthermore, it offers a promising strategy for cancer immunotherapy, highlighting its potential in improving response rates in ‘‘cold’’ tumors. Graphical Abstract

Abstract Dental fluorosis (DF) is a prevalent developmental defect of tooth enamel caused by exposure to excessive fluoride, with the severity dependent on various factors. This study aimed to investigate the association between DF and a specific genetic polymorphism (rs412777) in the COL1A2 gene among a Tunisian population. A case-control study was conducted from July to November 2022, involving a total of 95 participants including 51 cases and 44 controls. Dental examinations and genetic analysis were performed to assess the relationship between the COL1A2 gene polymorphism and DF. The results of allelic distribution revealed that A allele carriers were significantly protected against (DF) when compared to those with the C allele (C vs. A, p = 0.001; OR = 0.375 (0.207–0.672)). This suggests a strong correlation between the presence of the C allele and the risk of developing DF. Additionally, significant association between the CC genotype of rs412777 and an increased risk of DF was found under both codominant and dominant genetic models (P = 0.002 and P

High-fluorine groundwater is a potential threat to ecological environment and human health. The source and distribution of fluoride in groundwater in urbanized areas are complicated due to the double influence of geological background and human activities. It is of great significance to identify the characteristics of fluorine in groundwater to ensure the safety of groundwater.This study analyzed the environmental characteristics and main hydrogeochemical processes of high-fluorine groundwater in different urban functional areas of Lanzhou city, the largest industrial city in the arid region of Northwest China, based on the mathematical statistics, ion ratios and saturation index analysis. Then the influence of human activities on the migration and enrichment of fluoride was revealed. The results show that the ρ(F−) in the groundwater in the study area ranges from 0 to 4.8 mg/L, and 13 high-fluoride water samples exceeded the standard of groundwater quality Class III (1.0 mg/L), with an excess rate of 20.3%. Under the influence of intensity of human activity and sources of human input, the distribution characteristics of fluorine in groundwater in different urban functional areas are prominently different. The fluorine content of groundwater in the Xigu Petrochemical Industrial Zone is the highest, with the 47.4% of high-fluorine groundwater. While in commercial residential areas and new urban areas the fluorine content is relatively low, with the 7.1% and 9.7% of high-fluorine groundwater, respectively. The high-fluorine groundwater in the study area is mainly SO4•Cl—Na and Cl•SO4—Na type water, which is low in calcium, rich in sodium and weak in alkalinity. The dissolution of fluorinated minerals, precipitation/dissolution of calcite and dolomite, cation exchange between calcium and sodium on the surface of clay minerals, strong evaporation and salt effect are the main hydrogeochemical processes of fluoride enrichment in groundwater in the study area. Urbanization and industrialization lead to the further deterioration of natural high fluorine water, the industrial wastewater leakage from petrochemical leads to the further dissolution of fluoride in the formation, which is an important driving force for the enrichment of high fluorine groundwater in the Xigu Industrial Zone. The study provides basic information for the fluoride migration and enrichment in the high fluoride background area with human activities.

The emission and adsorption of mineral elements to dust from geogenic and anthropogenic sources are health challenges in residential areas. This study investigated, for the first time to the best of our knowledge, the presence of potentially toxic elements (PTEs), rare earth elements (REE) and fluorine (F) in collected dust samples from central Iran. Their associated health risks were estimated based on the Monte Carlo simulation. Results show that the morphology of the collected dust was uniform spherical particles and the predominant elements were Si and Ca. The highest concentration of PTEs was for Ca (mean: 36574 mg/kg) and Fe (mean: 30189 mg/kg) and the mean concentrations of As, Ni, Pb, Mn and Zn exceeded World Health Organization (WHO) guidelines, likely due to the anthropogenic activities such as metal melt factories. Fluorine averaged 159.4 mg/kg, and some detected elements originated from industrial and natural sources. The 5th, 50th, and 95th percentiles of the estimated Hazard Index (HI) were 0.13, 0.43, and 0.77, respectively, in adults and 1.00, 3.03, and 5.99, respectively, in children. The carcinogenic risk (LTCR) for adults and children exceeded the safety range (1 × 10−4), and their highest percentile was calculated at about 2.03 × 10−4 and 1.83 × 10−4, respectively. Furthermore, Ni was the most effective elements in LTCR. As a consequence, findings suggest a high potential carcinogenic risk due to the emission of dust in central Iran, especially for children, and the controlling of possible sources would benefit public health.

Fluoride-resistant Streptococcus mutans (S. mutans) might affect the ecological balance of biofilms in the presence of fluoride. We used a S. mutans and Candida albicans (C. albicans) cross-kingdom biofilm model to investigate whether fluoride-resistant S. mutans in biofilms would support C. albicans growth under fluoride stress and attenuate the in vitro anti-caries effect of fluorine. The impact of fluoride-resistant S. mutans on formation of cross-kingdom biofilms by S. mutans and C. albicans in the presence of fluoride was investigated in vitro using the crystal violet staining assay. Biofilm constitution was determined using colony-forming unit (CFU) counts and fluorescent in situ hybridization (FISH). Extracellular polysaccharide (EPS) generation in biofilms was determined by EPS/bacterial dying and water-insoluble polysaccharide detection. Acid production and demineralization were monitored using pH, lactic acid content, and transversal microradiography (TMR). The gene expression of microorganisms in the cross-kingdom biofilm was measured using qRT-PCR. Our results showed that both C. albicans and fluoride-resistant S. mutans grew vigorously, forming robust cross-kingdom biofilms, even in the presence of sodium fluoride (NaF). Moreover, fluoride-resistant S. mutans-containing cross-kingdom biofilms had considerable cariogenic potential for EPS synthesis, acid production, and demineralization ability in the presence of NaF than fluoride-sensitive S. mutans-containing biofilms. Furthermore, the gene expression of microorganisms in the two cross-kingdom biofilms changed dissimilarly in the presence of NaF. In summary, fluoride-resistant S. mutans in cross-kingdom biofilms supported C. albicans growth under fluoride and might attenuate the anti-caries potential of fluorine by maintaining robust cross-kingdom biofilm formation and cariogenic virulence expression in vitro in the presence of NaF.

Fluorine-19 (19F) is a nucleus of great importance in the field of Nuclear Magnetic Resonance (NMR) spectroscopy due to its high receptivity and wide chemical shift dispersion. 19F NMR plays crucial roles in both organic synthesis and biomedicine. Herein, a machine learning-based comprehensive 19F NMR chemical shift prediction model was established based on the experimental 19F NMR dataset from the book by Dolbier and the open NMR database nmrshiftdb2. Fluorine radical SMILES (Fr-SMILES) that reflected the fluorine chemical equivalence, was designed as the representation of fluorine in the molecule. Model trained with the graph convolution network (GCN) algorithm gave a low mean absolute error (MAE) of 3.636 ppm on the testing set. This model exhibits broad applicability and can effectively predict 19F NMR shifts for a wide range of organic fluorine molecules. We believe that the current work will provide a powerful tool for not only predicting 19F NMR shifts but also aiding in the analysis and identification of these shifts in diverse organic fluorine compounds. An online prediction platform was constructed based on the current model, which can be found at https://fluobase.cstspace.cn/fnmr.

This study developed a soft candy with peptide-zinc chelates using low-fluorine protein hydrolysates derived from Antarctic krill powder. To achieve this, the enzymatic hydrolysis conditions of the protein isolates were optimized through single-factor experiments. Protein hydrolysates were used to produce Antarctic krill peptides (AKP) through ceramic membrane microfiltration at various pressure levels. AKP-zinc chelates (AKP-Zn) were prepared by mixing AKP and zinc sulfate, subsequent to characterized the resulting complex. Finally, we examined the tolerance of AKP-Zn and soft candy containing AKP-Zn (SC-AKP-Zn) to simulated gastrointestinal digestion in vitro. The optimal enzyme mix was a 1:1 ratio of alkaline and flavored protease, with 4000 U/g enzymes, pH 7.5 and 3 h, and the ceramic membrane microfiltration increased the protein content in AKP by approximately 85.34 ± 3.54 %. Characterization showed that AKP effectively interacts zinc ions through bonding with oxygen and nitrogen atoms, helps the strength of AKP-Zn in various pH levels and simulated digestive systems. AKP-Zn and SC-AKP-Zn showed higher bioavailability compared to zinc sulfate and zinc gluconate. These results provide a solid theoretical foundation for creating ready-to-eat food products with AKP-Zn and offer new insights into the potential applications of Antarctic krill proteins.

To better understand the growth mechanism of diamond films via low-temperature chemical vapor deposition in a C-H-F atmosphere, this paper employed density functional theory based on first principle. It calculated the adsorption energy, reaction heat, and reaction energy barrier of H and F atoms undergoing extraction reactions on the hydrogen-terminated diamond surface. Additionally, the analysis included the adsorption of CF3, CF2, and CF growth groups on the active site substrate. The results show that compared with H atoms, F atoms are more likely to extract H from the surface of hydrogen terminated diamond and desorb it in the form of HF. This process is advantageous for generating more active sites at low temperatures in a C-H-F atmosphere. Both the structure and the absolute value of the adsorption energy of CF3, CF2, and CF groups are more favorable for the generation of the diamond phase after adsorption. Increasing the concentration of CF3, CF2, and CF growth groups appropriately can facilitate the growth of diamond phase at a higher rate.

Introduction: Fluoride is known to affect the nervous system, kidneys, liver, and gastrointestinal system, in addition to teeth and bones, when consumed in amounts exceeding 1 ppm per day over a prolonged period. YSR Kadapa district has been identified as one of the districts with endemic fluoride areas in Andhra Pradesh, India, by the Central Groundwater Board of India. Aim: To assess the toxic effects of fluoride on liver function in individuals affected and unaffected by dental fluorosis, who consume high levels of fluoride in water, in the endemic fluoride rural areas of YSR Kadapa district. Materials and Methods: A cross-sectional study was conducted in six villages of YSR Kadapa district, where the drinking water has elevated fluoride content. A total of 320 subjects were selected as study participants. The subjects were divided into two groups based on age and dental fluorosis: Group A, aged between 21 and 40 years, and Group B, aged between 41 and 60 years. Subjects of each group were further sub-grouped according to presence or absence of fluorosis. The selected subjects were screened for dental fluorosis, and Groups A and B were further divided into subgroups based on the presence or absence of dental fluorosis. Blood samples were collected from the participants to assess liver function using serum levels of liver function markers such as total bilirubin (direct and indirect), Serum Glutamic Oxaloacetic Transaminase (SGOT), Serum Glutamate Pyruvate Transaminase (SGPT), and Alkaline Phosphatase (ALP). Water and urine samples were also tested for fluoride levels using a fluoride ion meter. Statistical significance was determined using the t-test. Results: The mean fluoride levels in the water samples from the study areas ranged from 1.55±0.30 mg/L to 4.10±0.20 mg/L, and the urinary fluoride levels in the urine samples ranged from 0.54±0.46 mg/L to 2.13±0.845 mg/L. Among the study subjects, 60.6% (194) were affected by dental fluorosis, with 58.66% (88) belonging to Group A and 62.35% (106) belonging to Group B. There was no statistically significant difference in liver function markers in the serum between subjects with dental fluorosis and those without dental fluorosis in both groups (p>0.05), and the levels were within the normal reference range. Conclusion: This study found no impaired or altered liver function in adults affected by dental fluorosis and adults unaffected by dental fluorosis who consumed water with high levels of fluoride in the YSR Kadapa district.

Aerospace fasteners are a ubiquitous component within the aerospace, air-frame, and aero-engine industries due to the essential role they play in structural integrity. Ti-6Al-4V is a common material for fasteners to be manufactured from, owing to the excellent strength-to-density ratio the material possesses, allowing for weight-saving in an application where weight is penalised by loss of fuel efficiency. The manufacture of aerospace pins sees a solid-state lubricant applied over the surface of the bar stock, at the titanium manufacturers, which aids forging processing; however, this lubricant layer must be fully removed post-forging to allow for solution heat treatment operations to achieve the desired mechanical properties. Whilst the exact composition of the lubricant is proprietary to the titanium producers, this can make understanding the removal via salt bath processing difficult. As such, the lubricant has been analysed and characterised to understand the primary chemical composition of the lubricant. Furthermore, the salt bath process has been studied to understand the efficacy of the cleaning process and the impact that variation in the salt bath hold time has or that adding some method of agitation to the molten salt in the bath as it cleans the surface lubricant off the Ti-6Al-4V fastener has. The salt bath cleaning process can cause a bottleneck to the full manufacturing route for the aerospace fasteners. Results suggest that there is some margin to reduce the hold time, or that by adding in a dipping process to increase agitation, it can also allow for lower hold times.

Freshwater, vital for life and ecosystems, accounts for only 2.5% of Earth’s water, and is primarily located in polar caps, underground reservoirs, and surface water. Its quality varies due to environmental interactions, especially in groundwater. Tenerife, located in the Canary Islands, Spain, relies mainly on underground aquifers and tunnels capturing 51.6 cubic hectometers annually. Ensuring safe drinking water is a global challenge due to health risks from poor water quality, including diseases and cancer. Fluoride, sodium, and potassium are essential for health, and are mainly derived from groundwater as fluoride ions (F−) and sodium and potassium cations (Na+, K+). However, excessive F−, Na+, and K+ in drinking water is harmful. The World Health Organization limits F− to 1.5 mg/L, Na+ to 8.70 meq/L, and K+ to 0.31 meq/L. Geological, climatic, and human factors control the presence and transport of F−, Na+, and K+ in groundwater. Seismic events can impact water quality, with long-term effects linked to aquifer structure and transient effects from gas and fluid expansion during earthquakes. This study was motivated by a 3.8 mbLg earthquake in Tenerife in 2012, which allowed its impact on groundwater quality, specifically F−, Na+, and K− concentrations, to be examined. Post-earthquake, F− levels alarmingly increased to 8.367 meq/L, while Na+ and K+ showed no significant changes. This research quantifies the influence of earthquakes on increasing F− levels and evaluates F− reduction during low seismic activity, emphasizing the importance of water management on volcanic islands.

Novel tetrafluoro-λ6-sulfanyl-containing oligomers prepared by visible light-promoted addition of 1,4-(bis-chlorotetrafluoro-λ6-sulfanyl) benzene or 1,3-(bis-chlorotetrafluoro-λ6-sulfanyl) benzene to either 1,4-diethynyl benzene or the 1,3-diethynyl isomers form hard, stress resistant thin films on spin casting. The isomeric oligomers were utilized to establish a structure-function relationship for the mechanical properties of films prepared from the oligomers. The Young’s moduli of 145-nm-thick cured films could reach 60 GPa. The measured hardnesses, between 1.57 and 2.77 GPa, were more than double those of polymethyl methacrylate (PMMA) films. Curing of the tetrafluoro-λ6-sulfanyl-containing polymer films by UV irradiation resulted in coatings that exhibited remarkable hardness and modulus with good surface adhesion to silicon.

A series of compounds containing heterocyclic cores and gem-difluorocycloalkyl substituents was obtained under conditions of the parallel synthesis (i.e., simultaneous performance of reaction procedures, treatment of the reaction mixture, and product isolation for a number of similar transformations) using the reductive amination – the “Nitrogen deletion” reaction sequence. The synthesis of the target compounds commenced from heteroaromatic aldehydes and the corresponding gem-difluorocycloalkyl or (gem-difluorocycloalkyl)methyl amines and included the NaBH3CN-mediated reductive amination and “Nitrogen deletion” upon the action of Levin’s anomeric amide. It has been shown that the method can be used to obtain compounds with the aforementioned structural fragments separated by one or two methylene units. The developed protocol allowed for the preparation of a 12-member compound library (67 % synthetic efficiency). Therefore, this novel synthetic methodology is suitable for decorating heterocyclic cores with sp3-enriched substituents that are attractive for medicinal chemistry.

Abstract Despite the attractive properties of tetrafluorosulfanyl (SF4) compounds in drug discovery, medicinal research on SF4 molecules is hindered by the scarcity of suitable synthetic methodologies. Drawing inspiration from the well‐established Sonogashira cross‐coupling of terminal alkynes under Pd‐catalysis, it is envisioned that SF4‐alkynes can serve as effective coupling partners. To overcome the challenges associated with the electron‐deficient nature of SF4‐alkynes and the lability of the SF4 unit under transition‐metal catalysis, an aryl radical mediated Csp–Csp3 cross‐coupling reaction is successfully developed under Cu catalysis. This methodology facilitates the coupling of SF4‐alkynes with alkyl iodides, leading to the immediate synthesis of SF4‐attached drug‐like molecules. These findings highlight the potential impact of SF4‐containing molecules in the drug industry, paving the way for further research in this emerging field.

The title compound, C16H12FN3OS, a fluorinated dithiocarbazate imine derivative, was synthesized by the one-pot, multi-component condensation reaction of hydrazine hydrate, carbon disulfide, 4-fluorobenzyl chloride and isatin. The compound demonstrates near-planarity across much of the molecule in the solid state and a Z configuration for the azomethine C=N bond. The Z form is further stabilized by the presence of an intramolecular N—H...O hydrogen bond. In the extended structure, molecules are linked into dimers by N—H...O hydrogen bonds and further connected into chains along either [2\overline{1}0] or [100] by weak C—H...S and C—H...F hydrogen bonds, which further link into corrugated sheets and in combination form the overall three-dimensional network.

The results of modeling the properties of graphene modified with fluorine atoms are presented. The creation of modern semiconductor devices requires the introduction of new materials. Graphene is one of them that is of interest to researchers. The addition of fluorine, hydrogen, and other chemical elements to graphene makes it possible to create its modifications. On this basis, it is possible to develop semiconductor devices and devices with improved output characteristics. The basic characteristics of graphene modification with the use of fluorine atoms, namely, the band diagram, the dependences of the density of state (DOS parameter) of electrons and holes on the energy value, were obtained by first-principles modeling. The dependences of charge carrier mobility on temperature are determined for the iterative solution of the Boltzmann transport equation The dependences and parameters obtained for fluorinated graphene can serve as a basis for creating new heterostructural devices containing layers of modified graphene and other semiconductor materials.

Objective The South-to-North Water Transfer Project (SNWTP) has improved water use in northern China and further reduced deep groundwater extraction in the North China Plain. However, its impact on the evolution of regional groundwater hydrochemistry is still unknown. Methods In this paper, Cangzhou, which has experienced severe land subsidence due to groundwater overexploitation and has received water resources from the SNWTP since 2015, was selected as the study area to investigate the effects of the SNWTP on groundwater chemistry. In 2017 and 2021, groundwater samples from Ⅲ and Ⅳ confined aquifers were collected to determine the hydrochemical characteristics. Moreover, the average annual land subsidence of the regional layer was further evaluated by using SBAS-InSAR to identify the correlation between variations in land deformation and changes in groundwater chemistry. Results The results showed that in comparison with those before the SNWTP, the groundwater fluoride concentration was slightly decreased, and the area of the high value zone was reduced after the SNWTP. The groundwater environment characterized by high pH, TDS and HCO3- concentrations and low Ca2+ concentrations favors fluoride enrichment in groundwater. The water chemistry type did not change, and the salinity concentrations in groundwater increased after the SNWTP. Groundwater receives more dissolution of halite and fluorite. Meanwhile, the amount and rate of land subsidence slowed after the SNWTP. A small degree of land uplift was even observed in the southeastern part of the region. The inhibition of land subsidence constrains clay compaction and the release of high fluoride porewater trapped in the clay layer. As a result, aquifers Ⅲ and Ⅳ received more effective lateral recharge, thereby causing a slight decrease in groundwater fluoride. However, it needs to be noted that the longer hydraulic residence time and stronger water-rock interaction after the SNWTP interaction promote the dissolution of sediment evaporites into groundwater, leading to an increase in groundwater salinity. Conclusion The results of the study provide scientific support for drinking water safety and water resource management in Cangzhou.

The content of photosynthetic pigments in silver birch leaves (Betula pendula Roth.) is studied in areas with technogenic load and in baseline conditions. The research is performed in a forb type of birch forest in the suburbs of Krasnoyarsk. The wood stands exposed to a high level of technogenic pressure are located to the east of the city in the prevailing direction of air mass movement. The reference stands are under the least technogenic pollution and grow in western and northern areas of the city. The photosynthetic pigments are determined in ethanol extracts, calculated per 1 g of absolute dry mass (a.d.m.) of the leaves. A level of dust deposition on leaf surfaces is evaluated according to the method of J. Detrie (1973). The amounts of zinc, lead, aluminum, and fluorine ions are estimated in the washed leaves. It is found that the content of chlorophyll a inside the birch leaves from a relatively clean environment is slightly lower compared to the concentration in the leaves with the technogenic load. The chlorophyll b concentration is 2.5–3 times less than chlorophyll a and is close to the amount of carotenoids. The total chlorophyll content in birch leaves from different locations ranges from 5.4 to 7.3 mg/g a.d.m., the ratio of chlorophyll forms varies from 2.5 to 3, the proportion of net chlorophyll to carotenoids is between 3.4 and 3.8. As the level of dust increases, the content of the total photosynthetic pigments also rises. The accumulation of zinc ions in the birch leaf cells has a negative effect on pigment content, especially chlorophyll a, but doesn’t correlate with the ratio of the pigments. There has not been any correlation found between the lead and the photosynthetic pigments. It is noted that the rise in the concentration of aluminum significantly affects the contents of the chlorophylls and the carotenoids, while no relationship has been discovered between the concentration of aluminum and the proportion of the pigments. The relationship between fluorine and different forms of chlorophyll is absent as well. The results indicate the adaptive response of the photosynthetic system to the presence of pollutants in concentrations below the threshold values that are indicated in the literature. For citation: Stasova V.V., Skripal’shchikova L.N., Astrakhantseva N.V., Barchenkov A.P. Photosynthetic Pigments in Silver Birch Leaves (Betula pendula Roth.) with Technogenic Load. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 35–47. (In Russ.). https:// doi.org/10.37482/0536-1036-2023-3-35-47

Aim. To synthesize cyclobutane-derived amines and carboxylic acids bearing CH2F or CHF2 groups in the α position; to determine the regularities of the effect of fluoroalkyl substituents on the acid-base properties of the title compounds. Results and discussion. Synthetic approaches to 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanamines, 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanecarboxylic acids have been developed. It has been found that the pKa (pKa(H)) values measured for the title compounds, as well as for their non-substituted and CF3-substituted analogues, are consistent with the electron-withdrawing effect of the corresponding fluoroalkyl substituents. Experimental part. The synthesis of the title compounds commenced from the known ethyl 1-(hydroxymethyl)cyclobutanecarboxylate or the product of its Swern oxidation (the corresponding aldehyde) and included fluorination, alkaline ester hydrolysis (for carboxylic acids), and modified Curtius rearrangement (for amines). The pKa value was determined from the pre-equivalence point part of the titration curve using the standard acid-base titration. Conclusions. A newly developed synthetic approach to 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanamines, 1-(fluoromethyl)- and 1-(difluoromethyl)cyclobutanecarboxylic acids allows to obtain the title compounds in multigram quantities (up to 97 g). With a single exception, the acid-base properties of these products, as well as their parent non-substituted and CF3-substituted analogues, change in a monotonous manner in accordance with inductive electronic effect of the fluorine atom(s).

The approved anthelmintic salicylanilide drug niclosamide has shown promising anticancer and antimicrobial activities. In this study, new niclosamide derivatives with trifluoromethyl, trifluoromethylsulfanyl, and pentafluorosulfanyl substituents replacing the nitro group of niclosamide were prepared (including the ethanolamine salts of two promising salicylanilides) and tested for their anticancer activities against esophageal adenocarcinoma (EAC) cells. In addition, antifungal activity against a panel of Madurella mycetomatis strains, the most abundant causative agent of the neglected tropical disease eumycetoma, was evaluated. The new compounds revealed higher activities against EAC and fungal cells than the parent compound niclosamide. The ethanolamine salt 3a was the most active compound against EAC cells (IC50 = 0.8–1.0 µM), and its anticancer effects were mediated by the downregulation of anti-apoptotic proteins (BCL2 and MCL1) and by decreasing levels of β-catenin and the phosphorylation of STAT3. The plausibility of binding to the latter factors was confirmed by molecular docking. The compounds 2a and 2b showed high in vitro antifungal activity against M. mycetomatis (IC50 = 0.2–0.3 µM) and were not toxic to Galleria mellonella larvae. Slight improvements in the survival rate of G. mellonella larvae infected with M. mycetomatis were observed. Thus, salicylanilides such as 2a and 3a can become new anticancer and antifungal drugs.

Per- and polyfluoroalkyl substances (PFAS) are a group of fluorinated synthetic chemicals that are highly recalcitrant, toxic, and bio-accumulative and have been detected in biosolids worldwide, posing potential risks to humans and the environment. Recent studies suggest that the organic C-F bond in PFAS can be destructed and potentially mineralised into inorganic fluorides during thermal treatment. This study focuses on thermodynamic equilibrium investigations and the fate of fluorine compounds post-PFAS destruction during biosolid thermal treatment. The results indicate that gas-phase fluorine compounds are mainly hydrogen fluoride (HF) and alkali fluorides, whereas solid-phase fluorine compounds include alkaline earth fluorides and their spinels. High moisture and oxygen content in the volatiles increased the concentration of HF in the gas phase. However, adding minerals reduced the emission of HF in the gas phase significantly and enhanced the capture of fluorine as CaF2 spinel in the solid phase. This study also investigates the effect of feedstock composition on the fate of fluorine. High ash content and low volatile matter in the feedstock reduced HF gas emissions and increased fluorine capture in the solid product. The findings of this work are useful in designing thermal systems with optimised operating conditions for minimising the release of fluorinated species during the thermal treatment of PFAS-containing biosolids.

The kinetics of the F2 reaction with thiirane (C2H4S) was studied for the first time in a flow reactor combined with mass spectrometry at a total helium pressure of 2 Torr and in the temperature range of 220 to 800 K. The rate constant of the title reaction was determined under pseudo-first-order conditions, either monitoring the kinetics of F2 or C2H4S consumption in excess of thiirane or of F2, respectively: k1 = (5.79 ± 0.17) × 10−12 exp(−(16 ± 10)/T) cm3 molecule−1 s−1 (the uncertainties represent precision of the fit at the 2σ level, with the total 2σ relative uncertainty, including statistical and systematic errors on the rate constant being 15% at all temperatures). HF and CH2CHSF were identified as primary products of the title reaction. The yield of HF was measured to be 100% (with an accuracy of 10%) across the entire temperature range of the study. Quantum computations revealed reaction enthalpies ranging from −409.9 to −509.1 kJ mol−1 for all the isomers/conformers of the products, indicating a strong exothermicity. Boltzmann relative populations were then established for different temperatures.

Background: Amelogenesis imperfecta is a hereditary disorder affecting dental enamel. Among its phenotypes, hypocalcified AI is characterized by mineral deficiency, leading to tissue wear and, consequently, dental sensitivity. Excessive fluoride intake (through drinking water, fluoride supplements, toothpaste, or by ingesting products such as pesticides or insecticides) can lead to a condition known as dental fluorosis, which manifests as stains and teeth discoloration affecting their structure. Our recent studies have shown that extracts from Colombian native plants, Ilex guayusa and Piper marginatum, deposit mineral ions such as phosphate and orthophosphate into the dental enamel structure; however, it is unknown whether these extracts produce toxic effects on the dental pulp. Objective: To assess cytotoxicity effects on human dental pulp stem cells (hDPSCs) exposed to extracts isolated from I. guayusa and P. marginatum and, hence, their safety for clinical use. Methods: Raman spectroscopy, fluorescence microscopy, and flow cytometry techniques were employed. For Raman spectroscopy, hDPSCs were seeded onto nanobiochips designed to provide surface-enhanced Raman spectroscopy (SERS effect), which enhances their Raman signal by several orders of magnitude. After eight days in culture, I. guayusa and P. marginatum extracts at different concentrations (10, 50, and 100 ppm) were added. Raman measurements were performed at 0, 12, and 24 h following extract application. Fluorescence microscopy was conducted using an OLIMPUS fv1000 microscope, a live–dead assay was performed using a kit employing a BD FACS Canto TM II flow cytometer, and data analysis was determined using a FlowJo program. Results: The Raman spectroscopy results showed spectra consistent with viable cells. These findings were corroborated using fluorescence microscopy and flow cytometry techniques, confirming high cellular viability. Conclusions: The analyzed extracts exhibited low cytotoxicity, suggesting that they could be safely applied on enamel for remineralization purposes. The use of nanobiochips for SERS effect improved the cell viability assessment.

The impact of cadmium (Cd) and fluorine (F) on plant and human health has provoked significant public concern; however, their combined effects on plant and soil bacterial communities have yet to be determined. Here, a pot experiment was conducted to evaluate the effects of exogenous F, Cd, and their combination (FCd) on lettuce growth and soil bacterial communities. The results revealed that F and Cd concentrations in lettuce ranged from 63.69 to 219.45 mg kg−1 and 1.85 to 33.08 mg kg−1, respectively, presenting lower values in shoots than in the roots. Moreover, low contamination levels had no discernable influence on lettuce growth, but showed a synergistic negative on plant biomass when exogenous F and Cd exceeds 300 and 1.0 mg kg−1, respectively. The results of 16S rRNA gene sequencing indicated that the most abundant bacterial community at the phylum level was Proteobacteria, with the relative abundance ranging from 33.42% to 44.10% across all the treatments. The contaminants had little effect on bacterial richness but impacted the structure of bacterial communities. The PCoA showed that compartment and contaminants were the primary contributors to the largest source of community variation, while the VPA indicated that F and Cd synergistically affected the bacterial communities. In turn, lettuce plants could enhance the resistance to the combined stress by increasing the relative abundance of Oxyphotobacteria, Subgroup 6, Thermoleophilia, and TK10 classes in the rhizosphere.