Rapid and Efficient Removal of Perfluorooctanoic Acid from Water with Fluorine-Rich Calixarene-Based Porous Polymers

On account of its nonbiodegradable nature and persistence in the environment, perfluorooctanoic acid (PFOA) accumulates in water resources and poses serious environmental issues in many parts of the world. Here, we present the development of two fluorine-rich calix[4]arene-based porous polymers, FCX4-P and FCX4-BP, and demonstrate their utility for the efficient removal of PFOA from water. These materials featured Brunauer–Emmett–Teller (BET) surface areas of up to 450 m^{2} g^{-1}, which is slightly lower than their nonfluorinated counterparts (up to 596 m^{2} g^{-1}). FCX4-P removes PFOA at environmentally relevant concentrations with a high rate constant of 3.80 g mg^{-1} h^{-1} and reached an exceptional maximum PFOA uptake capacity of 188.7 mg g^{-1}. In addition, it could be regenerated by simple methanol wash and reused without a significant decrease in performance

Blunted angiogenesis and hypertrophy are associated with increased fatigue resistance and unchanged aerobic capacity in old overloaded mouse muscle.

We hypothesize that the attenuated hypertrophic response in old mouse muscle is (1) partly due to a reduced capillarization and angiogenesis, which is (2) accompanied by a reduced oxidative capacity and fatigue resistance in old control and overloaded muscles, that (3) can be rescued by the antioxidant resveratrol. To investigate this, the hypertrophic response, capillarization, oxidative capacity, and fatigue resistance of m. plantaris were compared in 9- and 25-month-old non-treated and 25-month-old resveratrol-treated mice. Overload increased the local capillary-to-fiber ratio less in old (15 %) than in adult (59 %) muscle (P < 0.05). Although muscles of old mice had a higher succinate dehydrogenase (SDH) activity (P < 0.05) and a slower fiber type profile (P < 0.05), the isometric fatigue resistance was similar in 9- and 25-month-old mice. In both age groups, the fatigue resistance was increased to the same extent after overload (P < 0.01), without a significant change in SDH activity, but an increased capillary density (P < 0.05). Attenuated angiogenesis during overload may contribute to the attenuated hypertrophic response in old age. Neither was rescued by resveratrol supplementation. Changes in fatigue resistance with overload and aging were dissociated from changes in SDH activity, but paralleled those in capillarization. This suggests that capillarization plays a more important role in fatigue resistance than oxidative capacity

Calix[4]arene-Based Porous Organic Nanosheets

Copyright © 2018 American Chemical Society. Calixarenes are a common motif in supramolecular chemistry but have rarely been incorporated in structurally well-defined covalent 2D materials. Such a task is challenging, especially without a template, because of the nonplanar configuration and conformational flexibility of the calixarene ring. Here, we report the first-of-a-kind solvothermal synthesis of a calix[4]arene-based 2D polymer (CX4-NS) that is porous, covalent, and isolated as few-layer thick (3.52 nm) nanosheets. Experimental and theoretical characterization of the nanosheets is presented. Atomic force microscopy and transmission electron microscopy results are consistent with the calculated lowest energy state of the polymer. In the lowest energy state, parallel layers are tightly packed, and the calixarenes adopt the 1,2-alternate conformation, which gives rise to a two-dimensional pattern and a rhombic unit cell. We tested the material's ability to adsorb I2 vapor and observed a maximum capacity of 114 wt %. Molecular simulations extended to model I2 capture showed excellent agreement with experiments. Furthermore, the material was easily regenerated by mild ethanol washings and could be reused with minimal loss of efficiency

Viologen-Based Conjugated Covalent Organic Networks via Zincke Reaction

Morphology influences the functionality of covalent organic networks and determines potential applications. Here, we report for the first time the use of Zincke reaction to fabricate, under either solvothermal or microwave conditions, a viologen-linked covalent organic network in the form of hollow particles or nanosheets. The synthesized materials are stable in acidic, neutral, and basic aqueous solutions. Under basic conditions, the neutral network assumes radical cationic character without decomposing or changing structure. Solvent polarity and heating method determine product morphology. Depending upon solvent polarity, the resulting polymeric network forms either uniform self-templated hollow spheres (HS) or hollow tubes (HT). The spheres develop via an inside-out Ostwald ripening mechanism. Interestingly, microwave conditions and certain solvent polarities result in the formation of a robust covalent organic gel framework (COGF) that is organized in nanosheets stacked several layers thick. In the gel phase, the nanosheets are crystalline and form honeycomb lattices. The use of the Zincke reaction has previously been limited to the synthesis of small viologen molecules and conjugated viologen oligomers. Its application here expands the repertoire of tools for the fabrication of covalent organic networks (which are usually prepared by dynamic covalent chemistry) and for the synthesis of viologen-based materials. All three materials - HT, HS, and COGF - serve as efficient adsorbents of iodine due to the presence of the cationic viologen linker and, in the cases of HT and HS, permanent porosity.The research described here was sponsored by New York University Abu Dhabi (NYUAD), UAE. G.D., T.S., S.K.S., R.J., and A.T. thank NYUAD for its generous support of the research program at NYUAD

Viologen-Based Conjugated Covalent Organic Networks via Zincke Reaction

Morphology influences the functionality of covalent organic networks and determines potential applications. Here, we report for the first time the use of Zincke reaction to fabricate, under either solvothermal or microwave conditions, a viologen-linked covalent organic network in the form of hollow particles or nanosheets. The synthesized materials are stable in acidic, neutral, and basic aqueous solutions. Under basic conditions, the neutral network assumes radical cationic character without decomposing or changing structure. Solvent polarity and heating method determine product morphology. Depending upon solvent polarity, the resulting polymeric network forms either uniform self-templated hollow spheres (<b>HS</b>) or hollow tubes (<b>HT</b>). The spheres develop via an inside-out Ostwald ripening mechanism. Interestingly, microwave conditions and certain solvent polarities result in the formation of a robust covalent organic gel framework (<b>COGF</b>) that is organized in nanosheets stacked several layers thick. In the gel phase, the nanosheets are crystalline and form honeycomb lattices. The use of the Zincke reaction has previously been limited to the synthesis of small viologen molecules and conjugated viologen oligomers. Its application here expands the repertoire of tools for the fabrication of covalent organic networks (which are usually prepared by dynamic covalent chemistry) and for the synthesis of viologen-based materials. All three materials<b>HT</b>, <b>HS</b>, and <b>COGF</b>serve as efficient adsorbents of iodine due to the presence of the cationic viologen linker and, in the cases of <b>HT</b> and <b>HS</b>, permanent porosity

Improved skeletal muscle oxidative enzyme activity and restoration of PGC-1α and PPARß/δ gene expression upon rosiglitazone treatment in obese patients with type 2 diabetes mellitus

Objective: To examine whether rosiglitazone alters gene expression of some key genes involved in mitochondrial biogenesis and oxidative capacity in skeletal muscle of type 2 diabetic patients, and whether this is associated with alterations in skeletal muscle oxidative capacity and lipid content.Design: Skeletal muscle gene expression, mitochondrial protein content, oxidative capacity and lipid accumulation were measured in muscle biopsies obtained from diabetic patients, before and after 8 weeks of rosiglitazone treatment, and matched controls. Furthermore, whole-body insulin sensitivity and substrate utilization were assessed.Subjects: Ten obese type 2 diabetic patients and 10 obese normoglycemic controls matched for age and BMI.Methods: Gene expression and mitochondrial protein content of complexes I&ndash;V of the respiratory chain were measured by quantitative polymerase chain reaction and Western blotting, respectively. Histochemical staining was used to quantify lipid accumulation and complex II succinate dehydrogenase (SDH) activity. Insulin sensitivity and substrate utilization were measured during a hyperinsulinemic&ndash;euglycemic clamp with indirect calorimetry.Results: Skeletal-muscle mRNA of PGC-1a and PPARb/d &ndash; but not of other genes involved in glucose, fat and oxidative metabolism &ndash; was significantly lower in diabetic patients (Po0.01). Rosiglitazone significantly increased PGC-1a (B2.2-fold, Po0.01) and PPARb/d (B2.6-fold, Po0.01), in parallel with an increase in insulin sensitivity, SDH activity and metabolic flexibility (Po0.01). Surprisingly, none of the measured mitochondrial proteins was reduced in type 2 diabetic patients, nor affected by rosiglitazone treatment. No alterations were seen in muscular fat accumulation upon treatment. Conclusion: These results suggest that the insulin-sensitizing effect of rosiglitazone may involve an effect on muscular oxidative capacity, via PGC-1a and PPARb/d, independent of mitochondrial protein content and/or changes in intramyocellular lipid.<br /