On the Lab. II building site

425 special CDSs in PCN033 (XLSX 29 kb

Spherical Indicatrices of a Bertrand Curve in Three Lie Groups

In this paper, new representations of a Bertrand curve pair in three dimensional Lie groups with bi-invariant metric are given. Besides, the spherical indicatrices of a Bertrand curve pair are obtain and the relations between the spherical indicatrices and new representations of Bertrand curve pair are shown.Comment: 12 page

Additional file 1 of Exploring barriers to and facilitators of the implementation of home rehabilitation care for older adults with disabilities using the Consolidated Framework for Implementation Research (CFIR)

Additional file 1. CFIR Guide

Metformin Contamination in Global Waters: Biotic and Abiotic Transformation, Byproduct Generation and Toxicity, and Evaluation as a Pharmaceutical Indicator

Metformin is the first-line antidiabetic drug and one of the most prescribed medications worldwide. Because of its ubiquitous occurrence in global waters and demonstrated ecotoxicity, metformin, as with other pharmaceuticals, has become a concerning emerging contaminant. Metformin is subject to transformation, producing numerous problematic transformation byproducts (TPs). The occurrence, removal, and toxicity of metformin have been continually reviewed; yet, a comprehensive analysis of its transformation pathways, byproduct generation, and the associated change in adverse effects is lacking. In this review, we provide a critical overview of the transformation fate of metformin during water treatments and natural processes and compile the 32 organic TPs generated from biotic and abiotic pathways. These TPs occur in aquatic systems worldwide along with metformin. Enhanced toxicity of several TPs compared to metformin has been demonstrated through organism tests and necessitates the development of complete mineralization techniques for metformin and more attention on TP monitoring. We also assess the potential of metformin to indicate overall contamination of pharmaceuticals in aquatic environments, and compared to the previously acknowledged ones, metformin is found to be a more robust or comparable indicator of such overall pharmaceutical contamination. In addition, we provide insightful avenues for future research on metformin

Density Functional Theory Calculations Decipher Complex Reaction Pathways of 6:2 Fluorotelomer Sulfonate to Perfluoroalkyl Carboxylates Initiated by Hydroxyl Radical

6:2 Fluorotelomer sulfonate (6:2 FTSA) is a ubiquitous environmental contaminant belonging to the family of per- and polyfluoroalkyl substances. Previous studies showed that hydroxyl radical (•OH) efficiently transforms 6:2 FTSA into perfluoroalkyl carboxylates (PFCAs) of different chain lengths (C2–C7), yet the reaction mechanisms were not elucidated. This study used density functional theory (DFT) calculations to map the entire reaction path of 6:2 FTSA initiated by •OH and experimentally verified the theoretical results. Optimal reaction pathways were obtained by comparing the rate constants calculated from the transition-state theory. We found that 6:2 FTSA was first transformed to C7 PFCA and C6F13•; C6F13• was then further reacted to C2–C6 PFCAs. The parallel addition of •OH and O2 to CnF2n+1• was essential to producing C2–C6 PFCAs. The critical step is the generation of alkoxyl radicals, which withdraw electrons from the adjacent C–C groups to result in chain cleavage. The validity of the calculated optimal reaction pathways was further confirmed by the consistency with our experimental data in the aspects of O2 involvement, identified intermediates, and the final PFCA profile. This study provides valuable insight into the transformation of polyfluoroalkyl substances containing aliphatic carbons in •OH-based oxidation processes

Density Functional Theory Calculations Decipher Complex Reaction Pathways of 6:2 Fluorotelomer Sulfonate to Perfluoroalkyl Carboxylates Initiated by Hydroxyl Radical

6:2 Fluorotelomer sulfonate (6:2 FTSA) is a ubiquitous environmental contaminant belonging to the family of per- and polyfluoroalkyl substances. Previous studies showed that hydroxyl radical (•OH) efficiently transforms 6:2 FTSA into perfluoroalkyl carboxylates (PFCAs) of different chain lengths (C2–C7), yet the reaction mechanisms were not elucidated. This study used density functional theory (DFT) calculations to map the entire reaction path of 6:2 FTSA initiated by •OH and experimentally verified the theoretical results. Optimal reaction pathways were obtained by comparing the rate constants calculated from the transition-state theory. We found that 6:2 FTSA was first transformed to C7 PFCA and C6F13•; C6F13• was then further reacted to C2–C6 PFCAs. The parallel addition of •OH and O2 to CnF2n+1• was essential to producing C2–C6 PFCAs. The critical step is the generation of alkoxyl radicals, which withdraw electrons from the adjacent C–C groups to result in chain cleavage. The validity of the calculated optimal reaction pathways was further confirmed by the consistency with our experimental data in the aspects of O2 involvement, identified intermediates, and the final PFCA profile. This study provides valuable insight into the transformation of polyfluoroalkyl substances containing aliphatic carbons in •OH-based oxidation processes

Data_Sheet_1_Building High Power Density of Sodium-Ion Batteries: Importance of Multidimensional Diffusion Pathways in Cathode Materials.PDF

Emerging sodium-ion batteries (SIBs) devices hold the promise to leapfrog over existing lithium-ion batteries technologies with respect to desirable power/energy densities and the abundant sodium sources on the earth. To this end, the discoveries on novel cathode materials with outstanding rate capabilities are being given high priority in the quest to achieve high power density SIBs devices, and the multi-dimensional Na+ migration pathways with low diffusion energy barriers are crucial. In light of this, the recent development of Prussian blue analogs and sodium superionic conductor (NASICON)-type materials with 3D Na+ diffusion pathways for building high power density NIBs are provided in this perspective. Ultimately, the future research directions to realize them for real applications are also discussed.</p

Bioaccessibility of PAHs in Fuel Soot Assessed by an in Vitro Digestive Model with Absorptive Sink: Effect of Food Ingestion

We investigated the effects of changing physiological conditions in the digestive tract expected with food ingestion on the apparent bioaccessibility (<i>B</i>_app) of 11 polycyclic aromatic hydrocarbons (PAHs) in a fuel soot. A previously established in vitro digestive model was applied that included silicone sheet as a third-phase absorptive sink simulating passive transfer of PAHs to intestinal epithelium in the small intestine stage. The <i>B</i>_app is defined as the fraction found in the digestive fluid plus sheet after digestion. We determined that <i>B</i>_app was independent of gastric pH and addition of nonlipid milk representing dietary proteins and carbohydrates, whereas it increased with bile acids concentration (2.0–10 g/L), small intestinal pH (5.00–7.35), and addition of soybean oil representing dietary lipid (100% and 200% of the mean daily ingestion by 2–5 year olds in the U.S.). <i>B</i>_app of PAHs increases with small intestinal pH due to the combined effects of mass transfer promotion from nonlabile to labile sorbed states in the soot, weaker sorption of the labile state, and increasingly favorable partitioning from the digestive fluid to the silicone sink. Under fed conditions, <i>B</i>_app increases with inclusion of lipids due to the combined effects of mass transfer promotion from nonlabile to labile states, and increasingly favorable partitioning into bile acid micelles. Our results indicate significant variability in soot PAH bioaccessibility within the range of physiological conditions experienced by humans, and suggest that bioaccessibility will increase with coconsumption of food, especially food with high fat content