An ambulatory dental treatment of a child with Rett syndrome and limited mouth opening under muscle relaxant-free general anesthesia: a case report.

BACKGROUND: Rett Syndrome (RTT) is a rare, severe, and progressive developmental disorder with intellectual disability. Anesthesia in RTT patients presents a range of challenges. We report a child with RTT who received dental treatment under muscle relaxant-free general anesthesia in our ambulatory center. CASE PRESENTATION: A 15-year-old girl with RTT was admitted to our dental clinic with multiple dental caries and residual roots. Dental treatment was scheduled under ambulatory general anesthesia. After anesthesia induction, a nasal tube was initiated under the guidance of a fiberoptic bronchoscope. Multimodal analgesia, body temperature monitoring, and postoperative nausea and vomiting prevention were applied. No muscle relaxants were used throughout the process. The endotracheal tube was successfully removed after the operation and the patient was discharged home the same day. CONCLUSION: An individualized anesthesia strategy enabled a quick and safe recovery for this RTT patient after dental treatment under muscle relaxant-free general anesthesia.

Preparation, Characterization and Antibacterial Property Analysis of Cellulose Nanocrystals (CNC) and Chitosan Nanoparticles Fine-Tuned Starch Film.

To improve the mechanical and antibacterial properties of traditional starch-based film, herein, cellulose nanocrystals (CNCs) and chitosan nanoparticles (CS NPs) were introduced to potato starch (PS, film-forming matrix) for the preparation of nanocomposite film without incorporation of additional antibacterial agents. CNCs with varied concentrations were added to PS and CS NPs composite system to evaluate the optimal film performance. The results showed that tensile strength (TS) of nanocomposite film with 0, 0.01, 0.05, and 0.1% (w/w) CNCs incorporation were 41, 46, 47 and 41 MPa, respectively. The elongation at break (EAB) reached 12.5, 10.2, 7.1 and 13.3%, respectively. Due to the reinforcing effect of CNCs, surface morphology and structural properties of nanocomposite film were altered. TGA analysis confirmed the existence of hydrogen bondings and electrostatic attractions between components in the film-forming matrix. The prepared nanocomposite films showed good antibacterial properties against both E. coli and S. aureus. The nanocomposite film, consist of three most abundant biodegradable polymers, could potentially serve as antibacterial packaging films with strong mechanical properties for food and allied industries.

Efficient Removal of Perfluorinated Chemicals from Contaminated Water Sources Using Magnetic Fluorinated Polymer Sorbents.

Efficient removal of per- and polyfluoroalkyl substances (PFAS) from contaminated waters is urgently needed to safeguard public and environmental health. In this work, novel magnetic fluorinated polymer sorbents were designed to allow efficient capture of PFAS and fast magnetic recovery of the sorbed material. The new sorbent has superior PFAS removal efficiency compared with the commercially available activated carbon and ion-exchange resins. The removal of the ammonium salt of hexafluoropropylene oxide dimer acid (GenX) reaches >99 % within 30 s, and the estimated sorption capacity was 219 mg g-1 based on the Langmuir model. Robust and efficient regeneration of the magnetic polymer sorbent was confirmed by the repeated sorption and desorption of GenX over four cycles. The sorption of multiple PFAS in two real contaminated water matrices at an environmentally relevant concentration (1 ppb) shows >95 % removal for the majority of PFAS tested in this study.

Reliability of 2 methods in maxillary transverse deficiency diagnosis.

INTRODUCTION: The objective of this research was to evaluate the reliability of 2 methods (Andrews' Element III analysis and Yonsei transverse analysis) in maxillary transverse deficiency diagnosis. METHODS: Plaster casts and cone-beam computed tomography images of 80 outpatients with skeletal Class I malocclusion (29 males and 51 females, mean age, 20.16 ± 8.22 years) were selected. Maxillary and mandibular width were measured, respectively, and independently by 2 examiners at an interval of 2 weeks, using Andrews' Element III analysis and Yonsei transverse analysis. Intraclass correlation coefficients and Bland-Altman plots of intraexaminer and interexaminer reliability were evaluated. After diagnosis, Cohen's kappa statistics were calculated to evaluate the diagnostic agreement. RESULTS: The intraclass correlation coefficients were all above 0.85, indicating good to excellent reliability. Compared with Andrews' Element III analysis, Yonsei transverse analysis had higher intraexaminer and interexaminer reliability in both maxillary and mandibular width measurements. Thirty-one to 42 of the patients were diagnosed with maxillary transverse deficiency by 2 examiners using 2 methods. The intraexaminer and interexaminer Cohen's kappa values of Yonsei transverse analysis were all higher than those of Andrews' Element III analysis. CONCLUSIONS: Both Andrews' Element III analysis and Yonsei transverse analysis had good to excellent reliability and substantial diagnostic agreement. Yonsei transverse analysis had higher reliability in maxillary and mandibular width measurements and higher diagnostic agreement, compared with Andrews' Element III analysis.

Two Zn(II)-based Coordination Polymers: Fe3+ Ion and Prevention Activity Detection On Postpartum Hemorrhage By Regulating Anticoagulant Factor Activity.

Two new Zn(II)-based coordination polymers {[Zn3(L1)6(H2O)]∙(H2O)4}n (1, HL1 = 4-(tetrazol-5-yl)phenyl-4,2':6',4″-terpyridine) and [Zn2Cl2(L2)2H2O]n (2, HL2 = 4-([2,2':6',2″'-terpyridin]-4'-yl)benzoic acid) have been successfully prepared using two similar organic ligands with distinct donor groups under similar reaction conditions. The distinct structural features and donor atoms make the two complexes show different water stability, and the complex 1 with good water stability, which can be utilized as the sensor for Fe3+ ion detection in water. The value of Stern-Volmer quenching constant of 1 to the Fe3+ is 5.77 × 104 M- 1, which lies in the top region of the reported CP-based sensors. The mechanism investigation reveals that the energy transfer of resonance from the complex 1 to the Fe3+ ion can account for its fluorescent quenching behavior. The treatment activity of compounds 1 and 2 on the postpartum hemorrhage (PPH) was assessed. First, the cytotoxicity of compounds 1 and 2 on human umbilical vein endothelial cells was assessed with Cell Counting Kit-8 detection kit. Then, to evaluate the prevention of compounds 1 and 2 on the PPH, we conducted the Lowry method and detected the clotting factor IX and anticoagulant factor III contents after the indicated treatment. Finally, the inflammatory response in mice was determined by ELISA method, and the IL-6 and IL-8 levels were determined.

Low-Fouling Fluoropolymers for Bioconjugation and In†Vivo Tracking.

The conjugation of hydrophilic low-fouling polymers to therapeutic molecules and particles is an effective approach to improving their aqueous stability, solubility, and pharmacokinetics. Recent concerns over the immunogenicity of poly(ethylene glycol) has highlighted the importance of identifying alternative low fouling polymers. Now, a new class of synthetic water-soluble homo-fluoropolymers are reported with a sulfoxide side-chain structure. The incorporation of fluorine enables direct imaging of the homopolymer by 19 F MRI, negating the need for additional synthetic steps to attach an imaging moiety. These self-reporting fluoropolymers show outstanding imaging sensitivity and remarkable hydrophilicity, and as such are a new class of low-fouling polymer for bioconjugation and in vivo tracking.

Integrating Fluorinated Polymer and Manganese-Layered Double Hydroxide Nanoparticles as pH-activated 19 F MRI Agents for Specific and Sensitive Detection of Breast Cancer.

19 F magnetic resonance imaging (19 F MRI) agents capable of being activated upon interactions with cancer triggers are attracting increasing attention, although challenges still remain for precise and specific detection of cancer tissues. In this study, a novel hybrid 19 F MRI agent for pH-sensitive detection of breast cancer tissues is reported, a composite system designed by conjugating a perfluoropolyether onto the surface of manganese-incorporated layered double hydroxide (Mn-LDH@PFPE) nanoparticles. The 19 F NMR/MRI signals from aqueous solutions of Mn-LDH@PFPE nanoparticles are quenched at pH 7.4, but "turned on" following a reduction in pH to below 6.5. This is due to partial dissolution of Mn2+ from the Mn-LDH nanoparticles and subsequent reduction in the effect of paramagnetic relaxation. Significantly, in vivo experiments reveal that an intense 19 F MR signal can be detected only in the breast tumor tissue after intravenous injection of Mn-LDH@PFPE nanoparticles due to such a specific activation. Thus pH-activated Mn-LDH@PFPE nanoparticles are a potential "smart" 19 F MRI agent for precise and specific detection of cancer diseases.

Fluorinated Glycopolymers as Reduction-responsive 19F MRI Agents for Targeted Imaging of Cancer.

Imaging agents that can be targeted to specific diseases and respond to the microenvironment of the diseased tissue are of considerable interest due to their potential in diagnosing and managing diseases. Here we report a new class of branched fluorinated glycopolymers as 19F MRI contrast agents that respond to a reductive environment, for targeted imaging of cancer. The fluorinated glycopolymers can be readily prepared by a one-pot RAFT polymerization of glucose- and fluorine-containing monomers in the presence of a disulfide-containing cross-linking monomer. The incorporation of glucose units along the polymer chain enables these fluorinated glycopolymers to effectively target cancer cells due to interactions with the overexpressed sugar transporters present on the cell surface. In addition, the polymers exhibit an enhanced 19F MRI signal in response to a reductive environment, one of the unique hallmarks of many cancer cells, demonstrating their potential as promising candidates for targeted imaging of cancer.

Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater.

Nanometer zero-valent iron (nZVI) has been widely used in the treatment of heavy metals such as hexavalent chromium (Cr(VI)). A novel composite of bead string-structured nZVI on modified activated carbon (nZVI-MAC) is prepared here, using polyethylene glycol as the stable dispersant rather than traditional ethanol during the loading process. The microstructure characterization shows that nZVI particles are loaded on MAC with a bead string structure in large quantity and stably due to the addition of hydroxyl functional groups on the surface by polyethylene glycol. Experiments on the treatment of Cr(VI) in wastewater show that the reaction process requires only 20 min to achieve equilibrium. The removal rate of Cr(VI) with a low concentration (80-100 mg/L) is over 99% and the maximum saturation removal capacity is up to 66 mg/g. The system converts Cr(VI) to trivalent chromium (Cr(III)) through an oxidation-reduction effect and forms an insoluble material with iron ions by coprecipitation, which is then adsorbed on the surface of the nZVI-MAC. The process conforms to the quasi-second order adsorption kinetics equation (mainly chemical adsorption process).

[Chemical Constituents from Macaranga denticulata Root].

OBJECTIVE: To study the chemical constituents from Macaranga denticulata Root. METHODS: The chemical constituents were isolated and purified by silica-gel column chromatography and recrystallization, and their structures were identified by physicochemical properties and spectral data. RESULTS: Nine compounds were isolated and identified as: gheddic acid (1), aleuritolic acid-3-acetate (2), ß-sitosterol (3), stigmast-4-en-6ß-ol-3 -one (4), 2α-hydroxyaleuritolic acid 3-p-hydroxybenzoate (5), scopoletin (6), daucosterol (7), 2, 6-dimethoxy-1,4-benzoquinone (8) and maslinic acid(9). CONCLUSION: Compounds 1-9 are obtained from this plant for the first time.

Integration of metal organic framework nanoparticles into sodium alginate biopolymer-based three-dimensional membrane capsules for the efficient removal of toxic metal cations from water and real sewage.

Sodium alginate (SA) biopolymer has been recognized as an efficient adsorbent material owing to their unique characteristics, including biodegradability, non-toxic nature, and presence of abundant hydrophilic functional groups. Accordingly, in the current research work, UiO-66-OH and UiO-66-(OH)2 metal organic framework (MOF) nanoparticles (NPs) have been integrated into SA biopolymer-based three-dimensional (3-D) membrane capsules (MCs) via a simple and facile approach to remove toxic metal cations (Cu2+ and Cd2+) from water and real sewage. The newly configured capsules were characterized by FTIR, SEM, XRD, EDX and XPS analyses techniques. Exceptional sorption properties of the as-developed capsules were ensured by evaluation of the pertinent operational parameters, i.e., contents of MOF-NPs (1-100 wt%), adsorbent dosage (0.001-0.05 g), content time (0-360 h), pH (1-8), initial concentration of metal cations (5-1000 mg/L) and reaction temperature (298.15-333.15 K) on the eradication of Cu2+ and Cd2+ metal cations. It was found that hydrophilic functional groups (-OH and -COOH) have performed an imperative role in the smooth loading of MOF-NPs into 3-D membrane capsules via intra/inter-molecular hydrogen bonding and van der waals potencies. The maximum monolayer uptake capacities (as calculated by the Langmuir isotherm model) of Cd2+ and Cu2+ by 3-D SGMMCs-OH were 940 and 1150 mg/g, respectively, and by 3-D SGMMCs-(OH)2 were 1375 and 1575 mg/g, respectively, under optimum conditions. The as-developed capsules have demonstrated superior selectivity against targeted metal cations under designated pH and maintained >80 % removal efficiency up to six consecutive treatment cycles. Removal mechanisms of metal cations by the 3-D SGMMCs-OH/(OH)2 was proposed, and electrostatic interaction, ion-exchange, inner-sphere coordination bonds/interactions, and aromatic ligands exchange were observed to be the key removal mechanisms. Notably, FTIR and XPS analysis indicated that hydroxyl groups of Zr-OH and BDC-OH/(OH)2 aromatic linkers played vital roles in Cu2+ and Cd2+ adsorption by participating in inner-sphere coordination interactions and aromatic ligands exchange mechanisms. The as-prepared capsules indicated >70 % removal efficiency of Cu2+ from real electroplating wastewater in the manifestation of other competitive metal ions and pollutants under selected experimental conditions. Thus, it was observed that newly configured 3-D SGMMCs-OH/(OH)2 have offered a valuable discernment into the development of MOFs-based water decontamination 3-D capsules for industrial applications.

Lipid sulfoxide polymers as potential inhalable drug delivery platforms with differential albumin binding affinity.

Inhalable nanomedicines are increasingly being developed to optimise the pharmaceutical treatment of respiratory diseases. Large lipid-based nanosystems at the forefront of the inhalable nanomedicines development pipeline, though, have a number of limitations. The objective of this study was, therefore, to investigate the utility of novel small lipidated sulfoxide polymers based on poly(2-(methylsulfinyl)ethyl acrylate) (PMSEA) as inhalable drug delivery platforms with tuneable membrane permeability imparted by differential albumin binding kinetics. Linear PMSEA (5 kDa) was used as a hydrophilic polymer backbone with excellent anti-fouling and stealth properties compared to poly(ethylene glycol). Terminal lipids comprising single (1C2, 1C12) or double (2C12) chain diglycerides were installed to provide differing affinities for albumin and, by extension, albumin trafficking pathways in the lungs. Albumin binding kinetics, cytotoxicity, lung mucus penetration and cellular uptake and permeability through key cellular barriers in the lungs were examined in vitro. The polymers showed good mucus penetration and no cytotoxicity over 24 h at up to 1 mg ml-1. While 1C2-showed no interaction with albumin, 1C12-PMSEA and 2C12-PMSEA bound albumin with KD values of approximately 76 and 10 µM, respectively. Despite binding to albumin, 2C12-PMSEA showed reduced cell uptake and membrane permeability compared to the smaller polymers and the presence of albumin had little effect on cell uptake and membrane permeability. While PMSEA strongly shielded these lipids from albumin, the data suggest that there is scope to tune the lipid component of these systems to control membrane permeability and cellular interactions in the lungs to tailor drug disposition in the lungs.

In vivo biocompatibility of two PEG/PAA interpenetrating polymer networks as corneal inlays following deep stromal pocket implantation.

This study compared the effects of implanting two interpenetrating polymer networks (IPNs) into rabbit corneas. The first (Implant 1) was based on PEG-diacrylate, the second (Implant 2) was based on PEG-diacrylamide. There were inserted into deep stromal pockets created using a manual surgical technique for either 3 or 6 months. The implanted corneas were compared with normal and sham-operated corneas through slit lamp observation, anterior segment optical coherence tomography, in vivo confocal scanning and histological examination. Corneas with Implant 1 (based on PEG-diacrylate) developed diffuse haze, ulcers and opacities within 3 months, while corneas with Implant 2 (based on PEG-diacrylamide) remained clear at 6 months. They also exhibited normal numbers of epithelial cell layers, without any immune cell infiltration, inflammation, oedema or neovascularisation at post-operative 6 month. Morphological studies showed transient epithelial layer thinning over the hydrogel inserted area and elevated keratocyte activity at 3 months; however, the epithelium thickness and keratocyte morphology were improved at 6 months. Implant 2 exhibited superior in vivo biocompatibility and higher optical clarity than Implant 1. PEG-diacrylamide-based IPN hydrogel is therefore a potential candidate for corneal inlays to correct refractive error.

A novel drug-phospholipid complex loaded micelle for baohuoside I enhanced oral absorption: in vivo and in vivo evaluations.

Baohuoside I is an effective anti-cancer drug currently used for a variety of cancers in vitro. Unfortunately, baohuoside I has a very poor solubility in both water and in organic solvents. Besides that, it is subject to significant efflux. This work therefore aimed at evaluating the ability of mixed micelles to solubilize baohuoside I, increase permeability and inhibit efflux of baohuoside I to promote oral absorption. A novel (TPGS-baohuoside I-phospholipid complex) mixed micelles was formed by phospholipid complex and TPGS to increase the solubility, enhance permeability, and inhibit efflux of baohuoside I. Micelle formation was confirmed by differential scanning calorimetry and transmission electron microscopy. The average diameters and efflux ratio of mixed micelles decreased as the ratio of TPGS increased with a respective increase in solubility of baohuoside I. Nevertheless, a slow release of baohuoside I from loaded micelles was noted. The results showed that at a 1:9 ratio for baohuoside I-phospholipid complex: TPGS in mixed micelles, solubility of baohuoside I increased up to 88 fold while the efflux ratio decreased by 85%. Their smaller size and higher zeta potential values indicated that mixed micelles would be easily absorbed and more stable. The relative bioavailability of the micelles (AUC(0-∞)) compared with baohuoside I (AUC(0-∞)) was 533%, demonstrating great potential for clinical application. Hence, the novel micelles formed with phospholipid complex and TPGS considerably increased drug concentration in the media and enhanced absorption.

Innovations in the Development of Promising Adsorbents for the Remediation of Microplastics and Nanoplastics - A Critical Review.

Microplastics and nanoplastics are being assumed as emerging toxic pollutants owing to their unique persistent physicochemical attributes, chemical stability, and nonbiodegradable nature. Owing to their possible toxicological impacts (not only on aquatic biota but also on humans), scientific communities are developing innovative technologies to remove microplastics and nanoplastics from polluted waters. Various technologies, including adsorption, coagulation, photocatalysis, bioremediation, and filtration, have been developed and employed to eliminate microplastics and nanoplastics. Recently, adsorption technology has been getting great interest in capturing microplastics and nanoplastics and achieving excellent removal performance. Therefore, this review is designed to discuss recent innovations in developing promising adsorbents for the remediation of microplastics and nanoplastics from wastewater and natural water. The developed adsorbents have been classified into four main classes: sponge/aerogel-based, metal-based, biochar-based, and other developed adsorbents, and their performance efficiencies have been critically examined. Further, the influence of various pertinent factors, including adsorbents' characteristics, microplastics/nanoplastics' characteristics, solution pH, reaction temperature, natural organic matter, and co-existing/interfering ions on the removal performance of advanced adsorbents, have been critically assessed. Importantly, the particle application of the developed adsorbents in removing microplastics and nanoplastics from natural water has been elucidated. In addition, barriers to market penetration of the developed adsorbents are briefly discussed to help experts transfer adsorption-based technology from laboratory-scale to commercial applications. Finally, the current knowledge gaps and future recommendations are highlighted to assist scientific communal for improving adsorption-based technologies to battle against microplastics and nanoplastics pollution.

Evaluation of Copper Levels in Dental Calculus of OSF Patients with Chewing Dried Areca-Nut Quids in Hunan Province of Mainland China.

Dental calculus is a potential material that can be used for assessing chronic exposure to trace heavy metals in oral cavity as it is a long-term reservoir. The aim of this study was to investigate the correlation between dental calculus copper levels and risk of oral submucous fibrosis (OSF) due to chewing dried areca-nut quids in Mainland China. This study included 34 OSF (grade 1) sufferers with dried areca-nut quids chewing as the patient group and 23 healthy individuals without areca-nut chewing as the control group. The dental calculus sample was obtained from all 57 participants and evaluated by inductively coupled plasma mass spectrometry (ICP-MS) for dental calculus level of copper. This work revealed that the mean copper level of dental calculus was significantly higher in OSF (grade 1) sufferers with areca-nut chewing than those in healthy individuals without areca-nut chewing (p < 0.001). This work provided an evidence to support that there may be a positive correlation between elevated levels of copper in dental calculus caused by chewing dried areca-nut quids and an increased risk of developing OSF in Mainland China.

Osteo-odonto keratoprosthesis: systematic review of surgical outcomes and complication rates.

Case series on osteo-odonto keratoprosthesis (OOKP) published in English from 1950-June 2010 were identified in Medline/PubMed. Indications for surgery, visual acuity, anatomical survival, complication and repeat surgery rates were compared among the different studies. Our own case series is a retrospective review of all OOKP surgeries performed in our center from February 2004-July 2011. Eight case series including our own were systematically reviewed. Sample sizes ranged from 4-181 eyes. The most common indications for surgery were severe cases of Stevens-Johnson syndrome and thermal and chemical burns that were unamenable to other forms of surgery or had had previous surgical failure. Anatomical survival rate in all the studies was 87.8% (range 67-100%) at 5 years, and three studies showed survival rates of 81.0% (range 65-98%) at 20 years. Visual acuity was more than 6/18 in 52% (range 46-72%) of the eyes with OOKP surgery. The most common intraoperative complication was vitreous hemorrhage (0-52%) and the most common long-term blinding complication was glaucoma (7-47%). Endophthalmitis rates ranged from 2-8%. The most common repeat surgical procedure was mucosal trimming due to mucosal overgrowth at the optical cylinder and mucosal grafting for extrusion of the OOKP or mucosal ulceration. Of the available biological and synthetic keratoprosthesis, OOKP appears to be an excellent option for the treatment of end-stage corneal diseases.

In vivo evaluation of titanium oxide and hydroxyapatite as an artificial cornea skirt.

Keratoprosthetic devices are subject to chronic inflammatory, pathological processes and the external environment that affect their stability and biocompatibility with the ocular surface and adjacent ocular tissues. We compared the corrosion resistance property and tissue-implant reaction of titanium oxide (TiO(2)) with hydroxyapatite (HA) in artificial tear fluid and a rabbit skin implantation model. The dissolution properties of the implant surfaces were evaluated with scanning electronic microscope (SEM) and atomic force microscope (AFM). Tissue inflammatory reactions were evaluated by Hematoxylin & Eosin staining, avidin biotin peroxidase complex (ABC) immunoassay and immunofluorescence. SEM and AFM images showed that there was less pitting corrosion on the surface of TiO(2) implants compared with HA. TiO(2) and HA exhibited a similar pattern of foreign body capsule formation and inflammatory cellular responses. The Collagen I/Collagen III ratio of the TiO(2) capsule was higher than that of the HA capsule. TiO(2) implants possess a high corrosion resistance property both in vitro and in vivo and the inflammatory cellular response to TiO(2) is similar to HA. With regards to corrosion resistance and inflammatory tissue responses, TiO(2) appears to be a promising material for keratoprosthetic skirt devices.

Accumulation of chiral pharmaceuticals (ofloxacin or levofloxacin) onto polyethylene microplastics from aqueous solutions.

Drug chirality is attracting increasing attention because the enantiomers of the same chiral pharmaceutical usually exhibit different biological activities, metabolic pathways, and toxicities. The ubiquitous presence of microplastics (MPs) can enrich organic pollutants commonly found in the environment. However, knowledge about the enrichment of pharmaceutical enantiomers to MPs is relatively limited. We investigated the occurrence of enantioselectivity of ofloxacin (OFL) and levofloxacin (LEV) in the adsorption processes on polyethylene (PE) and the interactions influenced by environmental factors. The results showed that the adsorption efficiency of OFL was generally 3-5% (p < 0.05) higher than that of LEV, indicating the different affinities of the enantiomers to PE, but the adsorption process of OFL and LEV on PE was both well described by pseudo-first-order kinetics and liner isotherm models. The chirality of OFL and LEV was not affected by sizes of PE particles and solution salinity due to the identical physicochemical properties. An examination of pH effect indicated that OFL showed better acid-base adaptability than LEV. Moreover, the differences in enantiomeric enrichment between OFL and LEV on PE were promoted with increasing UV light exposure time and natural organic matter (NOM) concentrations. Using Fourier transform infrared spectroscopy (FTIR), we demonstrated that the constituents of the functional groups in chiral NOM were greatly related to the enantiomer stereoselectivity of OFL, subsequently affecting their adsorption in a chiral environment. The excitation-emission matrix (EEM) spectra confirmed the enantioselective behaviors of chiral pharmaceuticals under UV light due to the different optical activity and humic acid-like and fulvic acid-like molecular structure of the enantiomers. These findings imply that the enantioselectivity of drug enantiomers should be considered in presence of microplastics, leading to a more accurate environmental fate and risks assessments of chiral pharmaceuticals.

Elucidating the Impact of Hydrophilic Segments on 19F MRI Sensitivity of Fluorinated Block Copolymers.

A major challenge in the preparation of polymeric 19F magnetic resonance imaging (MRI) contrast agents (CAs) is signal attenuation caused by reduced segmental mobility of partly fluorinated polymers possessing large numbers of fluorine atoms. Previous studies have thus mainly focused on the development of fluorinated segments for improved 19F MRI; however, detailed investigations of the role of hydrophilic segments on imaging performance remain scarce. In this study, three hydrophilic and biocompatible monomers, i.e., 2-(methylsulfinyl)ethyl acrylate (MSEA), oligo(ethylene glycol) methyl ether acrylate (OEGA), and oligo(2-methyl-2-oxazoline) acrylate (OMOXA), were used to prepare perfluoropolyether (PFPE)-containing amphiphilic block polymers through reversible addition-fragmentation chain-transfer (RAFT) polymerization. The effect of the different hydrophilic segments on 19F imaging performance was explored. The three polymers could be readily dissolved in aqueous solutions, forming assemblies with the hydrophobic PFPE as the core and the hydrophilic chains as the shell. Molecular dynamics simulations demonstrate that the POMOXA chains adopt a rigid, extended conformation, leading to a relatively short 19F NMR spin-spin relaxation time (T2), lower NMR detectable 19F spins (i.e., visibility), and the least intense 19F MRI signal. In contrast, although PMSEA-PFPE has a shorter 19F NMR T2 than POEGA-PFPE, the much higher 19F spin visibility enhances its MRI signal intensity. The result confirms the importance of maintaining both high fluorine visibility and long T2 relaxation time to prepare effective CAs and highlight the key role of the nonfluorinated hydrophilic segments in determining these parameters.