Discrimination and Identification of Aroma Profiles and Characterized Odorants in Citrus Blend Black Tea with Different Citrus Species

Citrus blend black teas are popular worldwide, due to its unique flavor and remarkable health benefits. However, the aroma characteristics, aroma profiles and key odorants of it remain to be distinguished and cognized. In this study, the aroma profiles of 12 representative samples with three different cultivars including citrus (Citrus reticulata), bergamot (Citrus bergamia), and lemon (Citrus limon) were determined by a novel approach combined head space-solid phase microextraction (HS-SPME) with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS). A total of 348 volatile compounds, among which comprised esters (60), alkenes (55), aldehydes (45), ketones (45), alcohols (37), aromatic hydrocarbons (20), and some others were ultimately identified. The further partial least squares discrimination analysis (PLS-DA) certified obvious differences existed among the three groups with a screening result of 30 significant differential key volatile compounds. A total of 61 aroma-active compounds that mostly presented green, fresh, fruity, and sweet odors were determined in three groups with gas chromatography-olfactometry/mass spectrometry (GC-O/MS) assisted analysis. Heptanal, limonene, linalool, and trans-β-ionone were considered the fundamental odorants associated with the flavors of these teas. Comprehensive analysis showed that limonene, ethyl octanoate, copaene, ethyl butyrate (citrus), benzyl acetate, nerol (bergamot) and furfural (lemon) were determined as the characterized odorants for each type.

Levels of Perfluoroalkyl Acids (PFAAs) in Human Serum, Hair and Nails in Guangdong Province, China: Implications for Exploring the Ideal Bio-Indicator

The widespread human exposure to perfluoroalkyl acids (PFAAs) has led to increasing public concern. In this study, we present a comprehensive measurement of total fluorine (TF), extractable organic fluorine (EOF), identified organic fluorine (IOF, total concentration of identified PFAAs quantified as fluorine) and 11 target PFAAs in human serum (n = 60), hair (n = 49) and nails (n = 39) collected from non-occupation exposed volunteers in 10 cities of Guangdong Province, China. The results indicated that EOF was the major form of fluorine in serum, accounting for 70-80% of TF. The levels of IOF contributed less than 10% of EOF. Perfluorooctane sulfonic acid (PFOS) was found to be the dominant PFAA with mean concentration of 23 ng·mL^-1 in serum, 35 ng·g^-1 in hair and 33 ng·g^-1 in nail, respectively. Short-chain PFAAs (C ≤ 10) were the predominant PFAAs in three matrices. Levels of PFOS, perfluorohexane sulfonic acid (PFHxS), perfluoroundecanoic acid (PFUdA) and perfluorotridecanoic acid (PFTrDA) in males are significantly higher than those in females (p < 0.01). Significant positive correlations were observed between nail and serum for PFOS (p < 0.01), perfluorooctanoic acid (PFOA) (p < 0.05) and PFHxS (p < 0.01), suggesting that human nails, a noninvasive sample, are a promising bio-indicator for PFAA risk assessment.

Fabrication of hydrolytically stable magnetic core-shell aminosilane nanocomposite for the adsorption of PFOS and PFOA

Aminosilane materials, with their low cost and ease of modification, have exhibited great potential for the adsorption of perfluorinated compounds (PFCs) from water. However, this kind of material may be facing two drawbacks during its application: low resistance to hydrolysis and difficulties in separation from the water matrix. This work proposed a strategy of grafting N-(2-aminoethyl) aminopropyltrimethoxysilane (AE-APTMS) on the surface of magnetic γ-Fe₂O₃ nanoparticles by full utilization of the sorption sites provided by the aminosilane and the magnetism by γ-Fe₂O₃. The FTIR and XRD results verified the formation of the magnetic AE-APTMS nanocomposite. The core-shell nanocomposite showed a superparamagnetic property and an isoelectric point at pH = 8.2. Particularly, compared to the aminopropyltriethoxysilane (APTES) nanocomposite, the AE-APTMS nanocomposite exhibited improved hydrolytic stability with 60% less loss of the amine groups during the 48 h adsorption process, as the longer alkyl chain hindered the aminosilane detachment. The AE-APTMS nanocomposite exhibited a rapid adsorption with the removal efficiency of 78% for perfluorooctane sulfonate (PFOS) and 65% for perfluorooctanoate (PFOA) due to the electrostatic interaction and hydrophobic interaction. The regeneration and reuse of the magnetic AE-APTMS nanocomposite were conveniently realized with the removal efficiency higher than 70% for both PFOS and PFOA even after 15 adsorption-desorption cycles. The stable magnetic aminosilane nanocomposite with the ease of separation may provide a new strategy to achieve the economical and effective removal of typical PFCs from water.

Hydrophobic ion pairing of a GLP-1 analogue for incorporating into lipid nanocarriers designed for oral delivery

The lipophilic character of peptides can be tremendously improved by hydrophobic ion pairing (HIP) with counterions to be efficiently incorporated into lipid-based nanocarriers (NCs). Herein, HIPs of exenatide with the cationic surfactant tetraheptylammonium bromide (THA) and the anionic surfactant sodium docusate (DOC) were formed to increase its lipophilicity. These HIPs were incorporated into lipid based NCs comprising 41% Capmul MCM, 15% Captex 355, 40% Cremophor RH and 4% propylene glycol. Exenatide-THA NCs showed a log Dlipophilic phase (LPh)/release medium (RM) of 2.29 and 1.92, whereas the log DLPh/RM of exenatide-DOC was 1.2 and -0.9 in simulated intestinal fluid and Hanks' balanced salts buffer (HBSS), respectively. No significant hemolytic activity was induced at a concentration of 0.25% (m/v) of both blank and loaded NCs. Exenatide-THA NCs and exenatide-DOC NCs showed a 10-fold and 3-fold enhancement in intestinal apparent membrane permeability compared to free exenatide, respectively. Furthermore, orally administered exenatide-THA and exenatide-DOC NCs in healthy rats resulted in a relative bioavailability of 27.96 ± 5.24% and 16.29 ± 6.63%, respectively, confirming the comparatively higher potential of the cationic surfactant over the anionic surfactant. Findings of this work highlight the potential of the type of counterion used for HIP as key to successful design of lipid-based NCs for oral exenatide delivery.

Intratumoral Administration of a Novel Cytotoxic Formulation with Strong Tissue Dispersive Properties Regresses Tumor Growth and Elicits Systemic Adaptive Immunity in In Vivo Models

The recent development of immune-based therapies has improved the outcome for cancer patients; however, adjuvant therapies remain an important line of treatment for several cancer types. To maximize efficacy, checkpoint inhibitors are often combined with cytotoxic agents. While this approach often leads to increased tumor regression, higher off target toxicity often results in certain patients. This report describes a novel formulation comprising a unique amphiphilic molecule, 8-((2-hydroxybenzoyl)amino)octanoate (SHAO), that non-covalently interacts with payloads to increase drug dispersion and diffusion when dosed intratumorally (IT) into solid tumors. SHAO is co-formulated with cisplatin and vinblastine (referred to as INT230-6). IT dosing of the novel formulation achieved greater tumor growth inhibition and improved survival in in vivo tumor models compared to the same drugs without enhancer given intravenously or IT. INT230-6 treatment increased immune infiltrating cells in injected tumors with 10% to 20% of the animals having complete responses and developing systemic immunity to the cancer. INT230-6 was also shown to be synergistic with programmed cell death protein 1 (PD-1) antibodies at improving survival and increasing complete responses. INT230-6 induced significant tumor necrosis potentially releasing antigens to induce the systemic immune-based anti-cancer attack. This research demonstrates a novel, local treatment approach for cancer that minimizes systemic toxicity while stimulating adaptive immunity.

Discerning the inefficacy of hydroxyl radicals during perfluorooctanoic acid degradation

Perfluorooctanoic acid (PFOA) is a recalcitrant contaminant of emerging concern, and there is growing interest in advanced oxidation processes to degrade it. However, there is ambiguity in the literature about the efficacy of hydroxyl radicals (OH) for degrading PFOA. Here, we resolve this controversy by comparing PFOA degradation by UV photolysis (254 nm, 6 × 10^-6 E/L.s) versus UV + H₂O₂, which produces OH. We optimized OH production in a UV + H₂O₂ system using nitrobenzene (NB) as a OH probe, but even under optimized conditions (i.e., 5 g/L H₂O₂), no significant difference occurred in PFOA removal by UV photolysis (21.1 ± 0.4%) versus UV + H₂O₂ (19.7 ± 0.7%) after 1-day treatment. Both treatments also resulted in similar daughter by-product concentrations and defluorination efficiencies (9.5 ± 1.7% for UV photolysis and 6.8 ± 1.0% for UV + H₂O₂), which indicates that OH is ineffective towards PFOA degradation and infers that other degradation mechanisms that are independent of OH production should be explored.

Development and In Vitro and In Vivo Evaluation of Microspheres Containing Sodium N-[8-(2-hydroxybenzoyl)amino]caprylate for the Oral Delivery of Berberine Hydrochloride

Microspheres containing absorption enhancer (sodium N-[8-(2-hydroxybenzoyl)amino]caprylate, SNAC) were developed to enhance the oral bioavailability of berberine hydrochloride (BER) with poor intestinal membrane permeability. Microspheres were prepared and characterized by particle size measurements, scanning electron microscopy, differential scanning calorimetry, BER payload and release, Caco-2 cell monolayer transport, and rat pharmacokinetics. The microspheres were spherical and had uniform size, high encapsulation efficiency and high loading capacity. In vitro release studies showed that BER-loaded microspheres had good sustained release characteristics. The Caco-2 cell monolayer transport study proved that SNAC could significantly enhance permeability of BER 2–3-fold. Pharmacokinetic studies demonstrated a 9.87-fold increase in area under the curve (AUC) of BER mixed with SNAC and a 14.14-fold increase in AUC of microspheres compared with BER alone. These findings indicate that SNAC is a promising absorption enhancer for oral delivery of BER in the form of both solution and microspheres.

The oxidation of cysteine-containing peptides caused by perfluoroalkane sulfonyl fluorides

Perfluorooctane sulfonyl fluoride (PFOSF) is the precursor of many fluorochemicals that are ubiquitous in the environment. However, its distribution and toxicology are rarely studied. In this work, the oxidability of PFOSF was found. PFOSF can accelerate oxidation of glutathione (GSH) to its oxidized form GSSG, and itself is reduced to a sulfinic acid. The yielded sulfinic acid was prepared and identified with high resolution mass spectrometry and NMR. Similar redox reactions were observed for PFOSF's short chain alternatives. The reduction potentials of perfluoroalkane sulfonyl fluorides (PFASFs) were determined to be -2.13 V vs. SCE with cyclic voltammetry, further demonstrating their oxidability. The peptide mixtures of GSH plus another cysteine-containing peptide were also oxidized by PFASFs to GSSG and an asymmetric disulfide GS-S-PEP. A single short-sequence PEP-SH could be oxidized to the symmetric disulfide PEP-S-S-PEP as the final product. In vitro experiments were carried out by adding PFASFs into rat liver S9 fractions. The turnover ratio of PFASFs were calculated to be about 4-10% by quantification of sulfinic acid with LC-MS/MS. Our work illustrates one of the potential metabolic pathways of PFASFs and demonstrates the oxidation of PEP-SHs by PFASFs, thus providing a preliminary exploration in the toxicology of these fluorochemicals.

Sorption behaviour of per- and polyfluoroalkyl substances (PFASs) in tropical soils

The sorption behaviour of three perfluoroalkyl substances (PFASs), namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonic acid (PFHxS), was determined on 28 tropical soils. Tropical soils are often highly weathered, richer in sesquioxides than temperate soils and may contain variable charge minerals. There are little data on sorption of PFASs in tropical soils. The highest K_d values were found for PFOS with mean values ranging from 0 to 31.6 L/kg. The K_d values for PFOA and PFHxS ranged from 0 to 4.9 L/kg and from 0 to 5.6 L/kg, respectively. While these values are in the range of literature sorption data, the average K_d values for PFOS and PFOA from the literature were 3.7 times and 3.6 times higher, respectively, than those measured in this study. Stepwise regression analysis did explain some of the variance, but with different explanatory variables for the different PFASs. The main soil properties explaining sorption for PFOS and PFOA were oxalate-extractable Al and pH, and for PFHxS was pH.

Visible and UV photocatalysis of aqueous perfluorooctanoic acid by TiO2 and peroxymonosulfate: Process kinetics and mechanistic insights

The global occurrence and adverse environmental impacts of perfluorooctanoic acid (PFOA) have attracted wide attention. This study focused on the PFOA photodegradation by using photocatalyst TiO₂ with peroxymonosulfate (PMS) activation. Aqueous PFOA (50 mg L^-1) at the pH 3 was treated by TiO2/PMS under 300 W visible light (400-770 nm) or 32 W UV light (254 nm and 185 nm). The addition of PMS induced a significant degradation of PFOA under powerful visible light compared with sole TiO₂. Under visible light, 0.25 g L^-1 TiO₂ and 0.75 g L^-1 PMS in the solution with the initial pH 3 provided optimum condition which achieved 100% PFOA removal within 8 h. Under UV light irradiation at 254 nm and 185 nm wavelength, TiO₂/PMS presented excellent performance of almost 100% removal of PFOA within 1.5 h, attributed to the high UV absorbance by the photocatalyst. The intermediates analysis showed that PFOA was degraded from a long carbon chain PFOA to shorter chain intermediates in a stepwise manner. Furthermore, scavenger experiments indicated that SO₄^•-radicals from PMS and photogenerated holes from TiO₂ played an essential role in degrading PFOA. The presence of organic compounds in real wastewater reduced the degradation efficacy of PFOA by 18-35% in visible/TiO₂/PMS system. In general, TiO₂/PMS could be an ideal and effective photocatalysis system for the degradation of PFOA from wastewater using either visible or UV light source.

Removing PFOA and nitrate by quaternary ammonium compounds modified carbon and its mechanisms analysis: Effect of base, acid or oxidant pretreatment

Acid/base/oxidant pretreatment influenced subsequent quaternary ammonium epoxide compounds modified carbon (QAE-AC) and hence PFOA and nitrate removal. This work discerned that the most favorable QAE-AC protocol for PFOA removal was achieved when the wood carbon pretreated with HNO3 to adjust the carbon's slurry pH to 4.77, and tailored with the QUAB188. For nitrate removal, the most favorable when the carbon was pretreated with NaOH to raise the carbon's slurry pH to 9.34, and then loaded with the QUAB360. Based on experimentally results and molecular model, we found that pore volume, phenolic groups and the surface charge were the main factors affecting the PFOA removal, while the only factor affecting nitrate removal was surface charge. The QUAB's epoxide functionalities have cross-linked with phenolics along the activated carbon's graphene edge sites. QAE is preferentially reacted with the phenolic in the micropores and mesopores of carbon, and some QAE molecules form new "pore-like structures" outside the pores with the graphene planes or other QAE molecules. This pore-like structure hosted adsorption capacity by the quaternary ammonium. The favorable PFOA adsorption sites were in smaller mesopores via both hydrophobic interaction and electrostatic interaction; and nitrate sorption was occurring in the smaller micropores via anion exchange. Therefore, it can be considered that QAE-AC can simultaneously adsorb PFOA and nitrate in water.

Investigating isomers/enantiomers of perfluorooctanoic acid in river water by gas chromatography-mass spectrometry with chiral derivatization

Perfluorooctanoic acid (PFOA) in environmental media contains numerous isomers/enantiomers because of the PFOA manufacturing process and biological degradation of PFOA precursors. Few methods for analyzing PFOA enantiomers have been described. A simple derivatization method using (S)-1-phenethyl chloride that was developed to allow PFOA isomers/enantiomers to be separated by gas chromatography and analyzed by electron-capture negative ionization mass spectrometry is described here. PFOA standards were analyzed, and enantiomers of the chiral isomers perfluoro-3-methyl-heptanoic acid, perfluoro-4-methyl-heptanoic acid, and perfluoro-3,5-dimethyl-hexanoic acid were separated using an HP-5MS column. Linear PFOA and perfluoro-6-methyl-heptanoic acid were chromatographically separated from these enantiomers. The linear ranges (giving correlation coefficients r > 0.997) of the calibration curves for the isomers were 0.010-3.00 ng/mL. PFOA isomer/enantiomer concentrations in river water were determined using the method. The method separated the enantiomers of perfluoro-3-methyl-heptanoic acid and perfluoro-4-methyl-heptanoic acid, the isomers of perfluoro-6-methyl-heptanoic acid, and linear PFOA in river water. No significant differences were found between the PFOA enantiomer/isomer compositions of the sample and technical PFOA. Enantiomer ratios can provide information about the sources and transport of pollutant isomers/enantiomers in the environment. Enantiomeric separation requires effective separation techniques. Our method achieved chiral separation using a non-chiral GC column that is often used in general analytical laboratories. The method could be used to investigate the sources and fates of PFOA and the isomers/enantiomers of other potentially toxic persistent pollutants in the environment and the risks posed to humans.

Improved photocatalysis of perfluorooctanoic acid in water and wastewater by Ga2O3/UV system assisted by peroxymonosulfate

Perfluorooctanoic acid (PFOA) has attracted considerable attention worldwide due to its widespread occurrence and environmental impacts. This research focused on the photocatalytic process for the treatment of PFOA in water and wastewater. Gallium oxide (Ga₂O₃) and peroxymonosulfate (PMS) were mixed directly in PFOA solution, which was irradiated under different light sources. The treatment system showed excellent performance that 100% PFOA was degraded within 90 min and 60 min under 254 nm and 185 nm UV irradiation, respectively. Moreover, the degradation efficacy was unaffected by initial PFOA concentration from 50 ng L^-1 to 50 mg L^-1. Acidic solution (pH 3) improved the degradation process. The quantum yield in the PMS/Ga₂O₃ system under UV light (254 nm) was estimated to be 0.009 mol E^-1. Scavengers such as tert-butanol (t-BuOH), disodium ethylenediaminetetraacetate (EDTA-Na₂) and benzoquinone (BQ) were added into PFOA solution to prove that sulfate radicals (SO₄^•-), superoxide radical (O₂^•-) and photogenerated electrons (e^-) were the main active species with strong redox ability for PFOA degradation in PMS/Ga₂O₃/UV system. Combined with the intermediates analysis, PFOA was degraded stepwise from long chain compound to shorter chain intermediates. In addition, PFOA in real wastewater exhibited similar degradation efficiency, together with 75-85% TOC removal by Ga₂O₃/PMS under 254 nm UV irradiation. Therefore, Ga₂O₃/PMS system was highly effective for PFOA photodegradation under UV irradiation, which has potential to be applied for the perfluoroalkyl substances (PFAS) treatment in water and wastewater.

Investigations on the phytotoxicity of perfluorooctanoic acid in Arabidopsis thaliana

Environmental contamination by perfluorooctanoic acid (PFOA) has raised concerns for years. Yet, little information on its phytotoxic effects and underlying mechanisms in higher plants is available. To this end, comparative analyses of the responses to PFOA exposure between shoots and roots in the model plant species Arabidopsis thaliana were performed at the physiological and molecular levels. Our results showed that PFOA exposure reduced Arabidopsis biomass in a dose-related manner, and shoot growth was more sensitive to PFOA than root growth. Consistently, PFOA accumulation and the levels of several metal elements, including Zn, Ca, Cu, and K, in addition to Fe, were more substantially affected in the shoots than in the roots. Transcriptomic analysis further showed that the shoot transcriptional profile was distinguishable from that of roots upon PFOA exposure. Nevertheless, some overlapping genes were present between the shoots and roots, mainly including transporter genes, Fe-deficiency-responsive genes, and oxidative stress-related genes. More importantly, a comparative analysis of ROS-associated genes in combination with other oxidative stress assays pointed out that PFOA triggered certain oxidative stress-associated events more strongly in shoots than in roots. Overall, the results demonstrated that PFOA exposure caused alterations in PFOA distribution, metal element balance, reconfiguration of transcriptomes, and induction of oxidative stress in a tissue-dependent manner in Arabidopsis thaliana.

Hyfraxinic Acid, a Phytotoxic Tetrasubstituted Octanoic Acid, Produced by the Ash (Fraxinus excelsior L.) Pathogen Hymenoscyphus fraxineus Together with Viridiol and Some of Its Analogues

A new tetrasubstituted octanoic acid, named hyfraxinic acid (1), was isolated together with known 1-deoxyviridiol (2), viridiol (3), nodulisporiviridin M (4), and demethoxyviridiol (5) from the organic extract of Hymenoscyphus fraxineus responsible for ash (Fraxinus excelsior L.) dieback in Europe. Hyfraxinic acid (1) was characterized, using spectroscopic methods, as 2,4-dihydroxy-7-methyl-6-methyleneoctanoic acid. Furthermore, the advanced Mosher method was used to determine the absolute configuration (3R) of 1-deoxyviridiol. Nodulisporiviridin M (4) was isolated for the first time from H. fraxineus. The phytotoxicity of each compound was tested by a leaf puncture assay on Celtis australis L., Quercus suber L., Hedera elix L., Juglans regia L., and Fraxinus angustifolia L. leaves. Compounds 1, 3, and 5 exhibited remarkable phytotoxicity on all plants tested, inducing necrotic lesions at concentrations of 1.0 and 0.5 mg/mL, while compounds 2 and 4 were found to be inactive in this bioassay. These results could contribute to a deeper understanding of the pathogenicity of H. fraxineus.

Development of a Tumor-Responsive Nanopolyplex Targeting Pancreatic Cancer Cells and Stroma

Desmoplasia plays a pivotal role in promoting pancreatic cancer progression and is associated with poor clinical outcome. Targeting the desmoplastic tumor microenvironment in combination with chemotherapy is therefore a promising strategy for pancreatic cancer therapy. Here, we report a novel biodegradable copolymer to codeliver LY2109761 (a TGF-β receptor I/II inhibitor) and CPI-613 (a novel chemotherapy agent) to desmoplastic stroma and tumor cells, respectively, in the tumor microenvironment. Hydrophobic CPI-613 is conjugated to the hydrophilic copolymer via a newly designed MMP-2-responsive linker to form a trigger-responsive nanopolyplex. LY2109761 is hydrophobic and encapsulated into the hydrophobic core of the nanopolyplex. The resulting nanopolyplex is modified with a plectin-1-targeting peptide to enhance the accumulation of the nanopolyplex in pancreatic tumors. The nanopolyplex aims to normalize the stroma by blocking the interaction between tumor cells and pancreatic stellate cells to inhibit the activation of pancreatic stellate cells and subsequently reduce the dense extracellular matrix. Normalized stroma increases the penetration of the nanopolyplex into the tumor. The nanopolyplex shows enhanced accumulation in xenograft pancreatic tumors in a biodistribution study. Moreover, the targeted nanopolyplex markedly inhibits tumor growth in an orthotopic pancreatic cancer mouse model by dual-targeting tumor cells and stroma. Overall, the multifunctional nanopolyplex is a promising platform for pancreatic cancer therapy.

Immobilisation of β-galactosidase within a lipid sponge phase: structure, stability and kinetics characterisation

In the formulation of an active enzyme enclosed in a matrix for controlled delivery, it is a challenge to achieve a high protein load and to ensure high activity of the protein. For the first time to our knowledge, we report the use of a highly swollen lipid sponge (L₃) phase for encapsulation of the large active enzyme, β-galactosidase (β-gal, 238 kDa). This enzyme has large relevance for applications in, e.g. the production of lactose free milk products. The formulation consisted of diglycerol monooleate (DGMO), and a mixture of mono-, di- and triglycerides (Capmul GMO-50) stabilised by polysorbate 80 (P80). The advantage of this type of matrix is that it can be produced on a large scale with a fairly simple and mild process as the system is in practice self-dispersing, yet it has a well-defined internal nano-structure. Minor effects on the sponge phase structure due to the inclusion of the enzyme were observed using small angle X-ray scattering (SAXS). The effect of encapsulation on the enzymatic activity and kinetic characteristics of β-galactosidase activity was also investigated and can be related to the enzyme stability and confinement within the lipid matrix. The encapsulated β-galactosidase maintained its activity for a significantly longer time when compared to the free solution at the same temperature. Differences in the particle size and charge of sponge-like nanoparticles (L₃-NPs) with and without the enzyme were analysed by dynamic light scattering (DLS) and zeta-potential measurements. Moreover, all the initial β-galactosidase was encapsulated within L₃-NPs as revealed by size exclusion chromatography.

Perfluorooctanoate in Aqueous Urea Solutions: Micelle Formation, Structure, and Microenvironment

Fluorinated surfactants are used in a wide range of applications that involve aqueous solvents incorporating various additives. The presence of organic compounds such as urea is expected to affect the self-assembly of fluorinated surfactants, however, very little is known about this. We investigated the effect of urea on the micellization in water of the common fluorinated surfactant ammonium perfluorooctanoate (APFO), and on the structure and microenvironment of the micelles that APFO forms. Addition of urea to aqueous APFO solution decreased the critical micellization concentration (CMC) and increased the counterion dissociation. The observed increase in surface area per APFO headgroup and decrease in packing density at the micelle surface suggest the localization of urea at the micelle surface in a manner that reduces headgroup repulsions. Micropolarity data further support this picture. The results presented here indicate that significant differences exist between urea effects on fluorinated surfactant and on hydrocarbon surfactant micellization in aqueous solution. For example, the CMC of sodium dodecyl sulfate (SDS) increased with urea addition, while the increase in surface area per headgroup and packing density of SDS with urea addition are much lower than those observed for APFO. This study informs fluorinated surfactant fate and transport in the environment, and also applications involving aqueous media in which urea or similar additives are present.

Vertical transport and sinks of perfluoroalkyl substances in the global open ocean

The ubiquitous occurrence of perfluoroalkyl substances (PFAS) in the open ocean has been previously documented, but their vertical transport and oceanic sinks have not been comprehensively characterized and quantified at the oceanic scale. During the Malaspina 2010 circumnavigation expedition, 21 PFAS were measured at the surface and at the deep chlorophyll maximum (DCM) in the Atlantic, Indian and Pacific oceans. In this work, we report an extended data set of PFAS dissolved phase concentrations at the DCM. ∑PFAS at the DCM varied from 130 to 11 000 pg L^-1, with a global average value of 500 pg L^-1. Perfluorooctanesulfonate (PFOS) abundance contributed 39% of ∑PFAS, followed by perfluorodecanoate (PFDA, 17%), and perfluorohexanoate (PFHxA, 12%). The relative contribution of the remaining compounds was below 10%, with perfluorooctanoate (PFOA) contributing only 5% to PFAS measured at the DCM. Estimates of vertical diffusivity, derived from microstructure turbulence observations in the upper (<300 m) water column, allowed the derivation of PFAS eddy diffusive fluxes from concurrent field measurements of eddy diffusivity and PFAS concentrations. The PFAS concentrations at the DCM predicted from an eddy diffusivity model were lower than field-measured concentrations, suggesting a relevant role of other vertical transport mechanisms. Settling fluxes of organic matter bound PFAS (biological pump), oceanic circulation and potential, yet un-reported, biological transformations are discussed.

Application of surfactant modified montmorillonite with different conformation for photo-treatment of perfluorooctanoic acid by hydrated electrons

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a class of highly persistent contaminants with high bioaccumulation and toxicity. Our previous studies showed that perfluorooctanoic acid (PFOA) can be completely defluorinated under UV irradiation in organo-montmorillonite/indole acetic acid (IAA) system. However, there is still lack of information for the degradation mechanism and the test for wastewater treatment. Here, we systematically investigated the defluorination reaction in the presence of different organo-montmorillonites and found that the degradation process was apparently controlled by the configuration of surfactants. In hexadecyltrimethyl ammonium (HDTMA)-modified montmorillonite, HDTMA exists as a tilt conformation and isolated clay interlayer from the aqueous solution, protecting hydrated electrons generated by photo-irradiation of IAA from quenching by oxygen. Defluorination hydrogenation process was the dominant degradation pathway. While in poly-4-vinylpyridine-co-styrene (PVPcoS)-modified montmorillonite, due to the multiple charges of PVPcoS, a flat conformation parallel to clay surface was expected. Hydroxyl radicals, which were generated by the reaction of hydrated electrons with oxygen molecules diffused into clay interlayer, are also involved in the degradation process. Our results further demonstrate that mixture modified montmorillonite could combine the advantages of both modifications, thus showing superior reactivity even for actual industrial wastewater without any pretreatment. This technique would have great potential for treatment of actual wastewater.

Photocatalytic defluorination of perfluorooctanoic acid by surface defective BiOCl: Fast microwave solvothermal synthesis and photocatalytic mechanisms

There is an urgent need for developing cost-effective methods for the treatment of perfluorooctanoic acid (PFOA) due to its global emergence and potential risks. In this study, taking surface-defective BiOCl as an example, a strategy of surface oxygen vacancy modulation was used to promote the photocatalytic defluorination efficiency of PFOA under simulated sunlight irradiation. The defective BiOCl was fabricated by a fast microwave solvothermal method, which was found to induce more surface oxygen vacancies than conventional solvothermal and precipitation methods. As a result, the as-prepared BiOCl showed significantly enhanced defluorination efficiency, which was 2.7 and 33.8 times higher than that of BiOCl fabricated by conventional solvothermal and precipitation methods, respectively. Mechanistic studies indicated that the defluorination of PFOA follows a direct hole (h⁺) oxidation pathway with the aid of •OH, while the oxygen vacancies not only promote charge separation but also facilitate the intimate contact between the photocatalyst surface and PFOA by coordinating with its terminal carboxylate group in a bidentate or bridging mode. This work will provide a general strategy of oxygen vacancy modulation by microwave-assisted methods for efficient photocatalytic defluorination of PFOA in the environment using sunlight as the energy source.

A phase inversion based nanoemulsion fabrication process to encapsulate vitamin D3 for food applications

A phase inversion based nanoemulsion fabrication process was developed to encapsulate vitamin D₃ by blending caprylic-/capric triglyceride (CCTG), Leciva S70, Kolliphor® HS 15, vitamin D₃ and aqueous phase (sodium chloride solution). In order to find out nanoparticle formation zone (NFZ), a ternary diagram was plotted with 41 possible combinations of three components CCTG, Kolliphor® HS 15 and aqueous phase. Out of forty one, only twelve combinations resulted in formation of stable nanoemulsion where the composition varied between 10%-40% (v/v), 10%-25% (v/v) and 35%-80% (v/v) for Kolliphor, CCTG and water respectively. Further, these 12 nanoemulsions were investigated for their particle size, zeta potential, emulsion stability, encapsulation efficiency and release kinetics (simulated digestion) of vitamin D. The nanoemulsion (NE-20) fabricated with 30% (v/v) Kolliphor, 20% (v/v) CCTG and 50% (v/v) aqueous phase was found to be the most suitable with respected to zeta potential, emulsion stability and encapsulation efficiency and also demonstrated high bioavailability of vitamin D as compared to other combinations and hence was selected for further physiochemical studies. The selected nanoemulsion was also investigated for particle size and zeta potential and stability of vitamin D₃ retention under different environmental stress conditions (i) temperature and humidity: (a) accelerated condition: 45 ± 2 °C and RH 75 ± 5%, (b) ambient condition: 25 ± 3 °C and RH 65 ± 5% and (c) refrigerated condition: 6 ± 2 °C and RH 55 ± 5% (ii) pH (3-7) under refrigerated condition and (iii) ionic strength: NaCl concentration (0 mM, 250 mM, 500 mM and 750 mM) under crefrigerated condition. Fourier transform infrared spectroscopy and High Perfomance Liquid Chromatograpy technique were used to study physico-chemical stability of encapsulated vitamin D₃ in the developed nanoemulsion. The sensory evaluation also indicated the acceptability of the selected nanoemulsion the purpose of fortification for beverages.

Pt(IV) Bifunctional Prodrug Containing 2-(2-Propynyl)octanoato Axial Ligand: Induction of Immunogenic Cell Death on Colon Cancer

The synthesis, characterization, and in vitro activity of a cyclohexane-1 R,2 R-diamine-based Pt(IV) derivative containing the histone deacetylase inhibitor rac-2-(2-propynyl)octanoato, namely, ( OC-6-44)-acetatodichlorido(cyclohexane-1 R,2 R-diamine)( rac-2-(2-propynyl)octanoato)platinum(IV), are reported together with those of its isomers containing enantiomerically enriched axial ligands. These Pt(IV) complexes showed comparable activity, of 2 orders of magnitude higher than reference drug oxaliplatin on three human (HCT 116, SW480, and HT-29) and one mouse (CT26) colon cancer cell lines. In vivo experiments were carried out on immunocompetent BALB/c mice bearing the same syngeneic tumor. The complex ( OC-6-44)-acetatodichlorido(cyclohexane-1 R,2 R-diamine)( rac-2-(2-propynyl)octanoato)platinum(IV) showed higher tumor mass Pt accumulation than oxaliplatin, due to its higher lipophilicity, with negligible nephro- and hepatotoxicities when administered intravenously. A remarkable tumor mass invasion by cytotoxic CD8+ T lymphocytes, following the Pt(IV) treatment, indicated a strong induction of immunogenic cell death.

The PFOA substitute GenX detected in the environment near a fluoropolymer manufacturing plant in the Netherlands

The ban on perfluorooctanoic acid (PFOA) has led to the production and use of alternative fluorinated compounds such as GenX. Limited information is available on the occurrence of this PFOA substitute. In this pilot study, we investigated the presence of GenX in/on grass and leaf samples collected near a fluoropolymer manufacturing plant in the Netherlands and in drinking water produced from surface and surface-water influenced groundwater intake points within 25 km from the plant. GenX was detected in/on all grass and leaf samples collected within 3 km north-east from the plant, with levels ranging from 1 to 27 ng/g wet weight (ww) and 4.3-86 ng/g ww, respectively. The PFOA levels in/on grass and leaves were lower, ranging from 0.7 to 11 ng/g ww and 0.9-28 ng/g ww, respectively. A declining concentration gradient of GenX and PFOA with increasing distance from the plant was observed, which suggests that the plant is a point source of GenX and was a point source for PFOA in the past. In all drinking water samples, GenX and PFOA were detected with levels ranging from 1.4 to 8.0 ng/L and 1.9-7.1 ng/L, respectively. The detection of GenX, which is only used since 2012, in/on grass and leaves and in drinking water indicates that GenX is now distributed through the environment. The presence of GenX and PFOA in/on grass and leaves within 3 km north-east of the plant also suggests that these chemicals could also be present on the locally grown food in gardens around the factory.

Renal function and isomers of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS): Isomers of C8 Health Project in China

Perfluoroalkyl substances (PFASs) are widely-utilized synthetic chemicals commonly found in industrial and consumer products. Previous studies have examined associations between PFASs and renal function, yet the results are mixed. Moreover, evidence on the associations of isomers of PFASs with renal function in population from high polluted areas is scant. To help to address this data gap, we used high performance liquid chromatography-mass spectrometry to measure serum isomers of perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), and other PFASs from 1612 adults residing in Shenyang, China, and characterized their associations with estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD). Results showed that after adjusted for multiple confounding factors, most of the higher fluorinated PFASs, except for PFOA and PFDA, were negatively associated with eGFR and positively associated with CKD. Compared with linear PFOS (n-PFOS), branched PFOS isomers (Br-PFOS) were more strongly associated with eGFR (Br-PFOS; β = -1.22, 95%CI: 2.02, -0.42; p = 0.003 vs. n-PFOS; β = -0.16, 95%CI: 0.98, 0.65; p = 0.691) and CKD (Br-PFOS; OR = 1.27; 95% CI: 1.02, 1.58; p = 0.037 vs. n-PFOS; OR = 0.98; 95% CI: 0.80, 1.20; p = 0.834). In conclusion, branched PFOS isomers were negatively associated with renal function whereas their linear counterparts were not. Given widespread exposure to PFASs, potential nephrotoxic effects are of great public health concern, Furthermore, longitudinal research on the potential nephrotoxic effects of PFASs isomers will be necessary to more definitively assess the risk.