Understanding the impact of climate variability and change is of great importance for developing adaptation and mitigation strategies. Coarse resolution data sets (such as climate reanalysis, numerical weather predictions, satellite products, and simulations of general circulation models) are important for reconstructing historical climate and predicting the future. However, scale discrepancy limits the coarse resolution data sets from being directly used for impact assessments and decision making. One solution for bridging this gap is to downscale coarse resolution data to the local scale (
By carrying out density functional theory calculations, we studied the CO oxidation promoted by cationic, neutral, and anionic Au trimers, which represent the prototypes of Au-cluster-based catalysts with different charge states. The reaction is explored along three possible pathways: one involves the reaction of the initial complexes between Au trimers and O2 with CO; another is related to O2 interacting with the complexes between Au trimers and CO; and the third refers to a self-promoting mechanism; that is, the second CO oxidation is promoted by a preadsorbed CO molecule. The theoretical results show that all three species may promote the reaction, as indicated by calculated low energy barriers and high exothermicities, supporting the fact that cationic, neutral, and anionic Au species were all observed to present catalytic activity toward CO oxidation. Along the reaction coordinates for all of the reactions, Au−carbonate species are not found to be the necessary intermediates, although they are calculated to be energetically very stable. In contrast, by performing atom-centered density matrix propagation molecular dynamics simulations, the formation of such highly stable species is attributed to the effective collision between Au−oxides and CO2 with the carbon atom of CO2 directly attacking the O atom in the oxides. The present results enrich our understanding of the catalytic oxidation of CO by Au-cluster-based catalysts.
Objectives
To evaluate the long‐term biosafety and efficacy of transplantation of human embryonic stem cells‐derived retinal pigment epithelial (hESC‐RPE) cells in early‐stage of Stargardt macular degeneration (STGD1).
Materials and methods
Seven patients participated in this prospective clinical study, where they underwent a single subretinal transplantation of 1 × 105 hESC‐RPE cells in one eye, whereas the fellow eye served as control. These patients were reassessed for a 60‐month follow‐up through systemic and ophthalmic examinations.
Results
None of the patients experienced adverse reactions systemically or locally, except for two who had transiently high intraocular pressure post‐operation. Functional assessments demonstrated that all of the seven operated eyes had transiently increased or stable visual function 1‐4 months after transplantation. At the last follow‐up visit, two of the seven eyes showed visual function loss than the baseline; however, one of them showed a stable visual acuity when compared with the change of fellow eye. Obvious small high reflective foci in the RPE layer were displayed after the transplantation, and maintained until the last visit. Interestingly, three categories of patients who were classified based on autofluorescence, exhibited distinctive patterns of morphological and functional change.
Conclusions
Subretinal transplantation of hESC‐RPE in early‐stage STGD1 is safe and tolerated in the long term. Further investigation is needed for choosing proper subjects according to the multi‐model image and function assessments.
Silk fibroin (SF) is a protein polymer derived from insects, which has unique mechanical properties and tunable biodegradation rate due to its variable structures. Here, the variability of structural, thermal, and mechanical properties of two domesticated silk films (Chinese and Thailand B. Mori) regenerated from formic acid solution, as well as their original fibers, were compared and investigated using dynamic mechanical analysis (DMA) and Fourier transform infrared spectrometry (FTIR). Four relaxation events appeared clearly during the temperature region of 25 °C to 280 °C in DMA curves, and their disorder degree (fdis) and glass transition temperature (Tg) were predicted using Group Interaction Modeling (GIM). Compared with Thai (Thailand) regenerated silks, Chin (Chinese) silks possess a lower Tg, higher fdis, and better elasticity and mechanical strength. As the calcium chloride content in the initial processing solvent increases (1%–6%), the Tg of the final SF samples gradually decrease, while their fdis increase. Besides, SF with more non-crystalline structures shows high plasticity. Two α- relaxations in the glass transition region of tan δ curve were identified due to the structural transition of silk protein. These findings provide a new perspective for the design of advanced protein biomaterials with different secondary structures, and facilitate a comprehensive understanding of the structure-property relationship of various biopolymers in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.