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摘要： A graphical abstract is available for this content

关键词： Nanoparticle   Renal clearance   Targeted drug delivery   Chronic kidney disease   Acute kidney disease  

摘要： Kidney-targeted nanoparticles have become of recent interest due to their potential to deliver drugs directly to diseased tissue, decrease off-target adverse effects, and increase overall tolerability to patients with chronic kidney disease that require lifelong drug exposure. Given the physicochemical properties of nanoparticles can drastically affect their ability to extravasate past cellular and biological barriers and access the kidneys, we surveyed the literature from the past decade and analyzed how nanoparticle size, charge, shape, and material density affects passage and interaction with the kidneys. Specifically, we found that nanoparticle size impacted the mechanism of nanoparticle entry into the kidneys such as glomerular filtration or tubular secretion. In addition, we found charge, aspect ratio, and material density influences nanoparticle renal retention and provide insights for designing nanoparticles for passive kidney targeting. Finally, we conclude by highlighting active targeting strategies that bolster kidney retention and discuss the clinical status of nanomedicine for kidney diseases.

关键词： MOFs   ozone oxidation   stability   structure evolution   postsynthesis  

摘要： Metal-organic frameworks (MOFs) are highly promising in many areas. Their application and postsynthesis under strong oxidative environments are emerging. However, the stability, physicochemical property evolution, and possible postmodification and postsynthesis of MOFs in strong oxidative solutions are largely unknown. In this paper, the behaviors of a series of MOFs in bubbled aqueous ozone (O-3) solutions are studied. The chosen MOFs are categorized into trimesic type including MIL-101(Fe) and MIL-96(Al);terephthalic type including MOF-74(Co), UiO-66(Zr), MIL-53(AI), and MIL-101(Cr);and imidazole type including ZIF-67(Co) and ZIF-8(Zn), based on the ligand structure. The intrinsic stability and evolution of the physicochemical properties of these MOFs during aqueous O-3 treatment are elucidated using structural, morphological, textural, thermal, and spectroscopic analyses. Several stable, metastable, and instable MOFs are identified. The critical parameters that determine the stability and capability for postsynthesis of these MOFs in aqueous 03 solutions are discussed. The stability follows the general order of trimesic-type > terephthalic-type >> imidazole-type MOFs because of the distinct antioxidation capability of the ligands. The effects of the ligand, metal cation, and their coordination number on stability are discussed. MIL-100(Fe), MIL-96(AI), and MOF-74(Co) are stable in aqueous O-3. UiO-66(Zr), MIL53(Al), and MIL-101(Cr) are metastable that their porosity, particle size, and crystallinity can be postmodified. ZIF-67(Co) and ZIF-S(Zn) are instable and can be gradually and completely disassembled. Their particle size and morphology and surface groups can be tuned by controlling the treatment time. Postsynthesis of metal hydroxides from ZIF-67(Co) and gradual release of dissolved zinc ion from ZIF-8(Zn) are achievable. The stable MIL-96(AI) shows promising performance in catalytic ozonation for degrading 4-nitrophenol, and the alpha-Co(OH)(2) derived from

关键词： Chemical Education Research   Upper-Division Undergraduate   Physical Chemistry   Professional Development  

摘要： Students' negative perceptions of physical chemistry courses are wellk-nown and are likely impacting their learning and performance in this upper-division course for majors. The syllabus can be the first interaction students have with a course and instructor and can be central to the expectations student set for the learning experience. While syllabi are not necessarily evidence of enacted classroom practice, their focus may be related to the enacted course design and instructional practices. Additionally, developing and modifying the document gives an instructor an opportunity to reflect on those same enacted practices, potentially facilitating a more learning-centered experience for students. In this study, we collected physical chemistry syllabi from across the United States and evaluated the learning-centeredness of this document using the Measuring the Promise syllabus rubric. Physical chemistry syllabi from 2017 to 2019 were largely content-focused. Analysis of the specific components of syllabi revealed potential improvements that may shift the focus of physical chemistry syllabi toward the learning end of the learning-centeredness spectrum. These include communicating learning goals and objectives across a wide range of dimensions, introducing transparency about the alignment of assessments with objectives, and creating supportive classroom climates via the syllabus.

关键词： Ionic liquids  

摘要： Ionic liquids (ILs) have gained a lot of attention as alternative solvents in many fields of science in the last two decades. It is known that the type of anion has a significant influence on the macroscopic properties of the IL. To gain insights into the molecular mechanisms responsible for these effects it is important to characterize these systems at the microscopic level. Such information can be obtained from nuclear spin-relaxation studies which for compounds with natural isotope abundance are typically performed using direct H-1 or C-13 measurements. Here we used direct N-15 measurements to characterize spin relaxation of non-protonated nitrogens in imidazolium-based ILs which are liquid at ambient temperature. We report heteronuclear H-1-N-15 scalar coupling constants ((n)J(HN)) and N-15 relaxation parameters for non-protonated nitrogens in ten 1-ethyl-3-methylimidazolium ([C2C1IM](+))-based ILs containing a broad range of anions. The N-15 relaxation rates and steady-state heteronuclear N-15-{H-1} NOEs were measured using direct N-15 detection at 293.2 K and two magnetic field strengths, 9.4 T and 16.4 T. The experimental data were analyzed to determine hydrodynamic characteristics of ILs and to assess the contributions to N-15 relaxation from N-15 chemical shift anisotropy and from H-1-N-15 dipolar interactions with non-bonded protons. We found that the rotational correlation times of the [C2C1IM](+) cation determined from N-15 relaxation measurements at room temperature correlate linearly with the macroscopic viscosity of the ILs. Depending on the selected anion, the N-15 relaxation characteristics of [C2C1IM](+) differ considerably reflecting the influence of the anion on the physicochemical properties of the IL.

关键词： Chitosan  

摘要： Given the intertwined physicochemical effects exerted in vivo by both natural and synthetic (e.g., biomaterial) interfaces on adhering cells, the evaluation of structure-function relationships governing cellular response to micro-engineered surfaces for applications in neuronal tissue engineering requires the use of in vitro testing platforms which consist of a clinically translatable material with tunable physiochemical properties. In this work, we micro-engineered chitosan substrates with arrays of parallel channels with variable width (20 and 60 mu m). A citric acid (CA)-based crosslinking approach was used to provide an additional level of synergistic cueing on adhering cells by regulating the chitosan substrate's stiffness. Morphological and physicochemical characterization was conducted to unveil the structure-function relationships which govern the activity of rat dorsal root ganglion neurons (DRGs) and human mesenchymal stem cells (hMSCs), ultimately singling out the key role of microtopography, roughness and substrate's stiffness. While substrate's stiffness predominantly affected hMSC spreading, the modulation of the channels' design affected the neuronal architecture's complexity and guided the morphological transition of hMSCs. Finally, the combined analysis of tubulin expression and cell morphology allowed us to cast new light on the predominant role of the microtopography over substrate's stiffness in the process of hMSCs neurogenic differentiation.

关键词： Cementitious composite   Graphene nanoplate   Graphite plate   Physicochemical property   Piezoresistivity   Microstructure  

摘要： Graphene nanoplate (GNP) and graphite plate (GP) are promising functional nanofillers for smart self sensing cementitious composites. The effects of GNP and GP on physicochemical, mechanical and piezoresistive properties of cementitious composite were investigated in this paper. The results show that cement hydration was accelerated with the increased amounts of GNP and GP because of nucleation effect. The electrical resistivity of GNP-cementitious composites was always lower than the counterpart with GP with the same concentration. On the other hand, percolation occurred for the GNP/cementitious composites at the dosages from 2 to 3% (by weight), while it never happens for the GP/cementitious composites. Moreover, the GNP/cementitious composites reached the maximum mechanical strength when the GNP content was 1.0%, while for the GP/cementitious composites, only minor strength improvement was obtained with a dosage of 0.5% GP. As for the piezoresistivity, the cementitious composites with GNP exhibited higher fractional changes of resistivity. Irreversible resistivity happened for 2-3% GP/cementitious composites subjected to cyclic compression, due to the poor and loose microstructures. The outcomes are expected to provide an insight into the application of GNP/cementitious and GP/cement composites as cement-based sensors for the future structural health monitoring. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Asphalt   Aqueous solutions   Morphology   Structure   Components  

摘要： Aqueous solution is one of the main factors of asphalt pavement disease. However, the physicochemical changes of asphalt are ambiguous during immersion in different aqueous solutions. This study evaluated the physicochemical properties of asphalt under the action of different aqueous solutions to further understand the mechanism of moisture erosion. The morphology, chemical structure and four components of asphalt were observed after immersion, while the pH value, total organic carbon (TOC) and characteristic functional groups of residual solutions were monitored. The test results showed that aqueous solution could change the bee structure on the asphalt surface and increased the mean roughness. The carbonyl index (I-C=O) and sulfoxide index (I-S=O) of asphalt increased with immersion time. And the asphaltenes of asphalt fluctuated and eventually increased during immersion. Solute could accelerate the erosion on asphalt through interaction, the degree of which increased in the order, Na2SO4 saline < NaCl saline < pH 3 acid < pH 11 alkali. (C) 2021 The Authors. Published by Elsevier Ltd.

关键词： biodegradable   biomaterials   degradation   proteins  

摘要： In this research, a novel pH and temperature-sensitive biodegradable oligomer serin-b-poly(lactide)-b-poly (ethylene glycol)-b-poly(lactide)-b- oligomer serin (OS-PLA-PEG-PLA-OS) pentablock copolymer was synthesized with modification of serine to sulfonamide group. The properties of the different pentablock copolymer structures were detail characterized. The copolymer solution easily flowed at high pH and changed to gel state at physiological conditions (37 degrees C, pH 7.4). The sol to gel behavior of these block copolymer solutions were controllable by tuning the length of PEG segment, PLA/PEG block ratio, the molecular weight and the concentration of the pentablock copolymer. The in vivo gelation of the copolymer solution was investigated. The stable gel was formed after injection into the back of the adult male Mus musculus Swiss Albino mice. The degradation process was observed after 6 weeks and showed that the hydrogel depot was bioresorbable without any detection of inflammation sign. The results in this study suggest that the OS-PLA-PEG-PLA-OS pentablock copolymer has the potential application as an injectable delivery vehicle for therapeutic drugs that easily denatured at low-pH condition.

关键词： Core-shell tecto dendrimers   Characterization   NMR techniques   Diffusion NMR  

摘要： Core-shell tecto dendrimers (CSTDs) are a class of superstructured dendrimeric nanoconstructs with similar structural characteristics and biomedical performances to the high-generation dendrimers that can be decorated with zwitterions to be availed of good antifouling properties for different biomedical applications. Characterization of the CSTD-based dendrimeric derivatives remains to be a great challenge. Here, we attempted to utilize nuclear magnetic resonance (NMR) technologies to investigate the structure and hydrodynamic size of CSTDs functionalized with zwitterionic carboxybetaine acrylamide (CBAA) and confirmed their antifouling property through protein resistance assay. In this study, we initially prepared CSTDs by supramolecular assembly of betacyclodextrin (beta-CD)-modified generation 5 (G5) poly(amidoamine) (PAMAM) dendrimers as cores and adamantane (Ad)-decorated G3 PAMAM dendrimers as shells, and then partially modified the CSTD terminal amines with CBAA. The dendrimeric products were thoroughly characterized. Our results show that the obtained CSTDs display strong correlation signals between the Ad and beta-CD protons in the two-dimensional NMR spectrum, indicating the strong host-guest interaction existing between G3-Ad and G5-CD in the structure of CSTDs. Diffusion NMR measurements reveal that the hydrodynamic diameter of CSTDs is smaller after partial CBAA surface modification, possibly due to the tightened molecular volume after zwitterionic modification. Lastly, the CBAA-modified CSTDs were demonstrated to have good antifouling property through protein resistance assay. Our findings provide a new strategy to study the framework of the developed CSTDs and CBAA-modified CSTDs, facilitating their further design and surface modification for various biomedical applications.