Diatom is an important group of marine algae and contributes to around 20% of the global photosynthetic carbon fixation. Photosystem I (PSI) of diatoms is associated with a large number of fucoxanthin-chlorophyll a/c proteins (FCPIs). We report the structure of PSI-FCPI from a diatom Chaetoceros gracilis at 2.38 Å resolution by single-particle cryo-electron microscopy. PSI-FCPI is a monomeric supercomplex consisting of 12 core and 24 antenna subunits (FCPIs), and 326 chlorophylls a, 34 chlorophylls c, 102 fucoxanthins, 35 diadinoxanthins, 18 β-carotenes and some electron transfer cofactors. Two subunits designated PsaR and PsaS were found in the core, whereas several subunits were lost. The large number of pigments constitute a unique and huge network ensuring efficient energy harvesting, transfer and dissipation. These results provide a firm structural basis for unraveling the mechanisms of light-energy harvesting, transfer and quenching in the diatom PSI-FCPI, and also important clues to evolutionary changes of PSI-LHCI.
Layered 2D perovskites have been extensively investigated by scientists with photovoltaics (PV) expertise due to their good environmental stability. However, a random phase distribution in the perovskite film could affect both the performance and stability of the devices. To overcome this problem, we propose multifunctional interface engineering of 2D GA 2 MA 4 Pb 5 I 16 perovskite by employing guanidinium bromide (GABr) on top of it to optimize the secondary crystallization process. It is found that GABr treatment can facilitate to form a shiny and smooth surface of the 2D GA 2 MA 4 Pb 5 I 16 film with excellent optoelectronic properties. Thus, we realize efficient and stable 2D perovskite solar cells (PSCs) with a champion power conversion efficiency (PCE) of 19.3% under AM 1.5G illumination. Additionally, the optimized device without encapsulation could retain 94% of the initial PCE for more than 3000 h after being stored under ambient conditions.
In nano-confinements, aqueous solutions can be found to remain in a liquid state at subfreezing temperatures. The finding provides a means of entering into previously inaccessible temperature regions for studying the dynamics and structure of bulk liquid. Here we show that studying biomolecular structures in nano-confinements improves the accuracy of cryostructures and provides better insight into the relationship between hydration water and biomolecules. Synthetic prion protein peptides are studied in two experimental conditions: (i) in confined nanochannels within mesoporous materials, and (ii) in vitrified bulk solvents, with a temperature range of 50-275 K, using cw/pulse ESR techniques. A large inhomogeneous lineshape broadening is only observed for the spectra from the vitrified bulk solvent below 70 K, suggesting a possible peptide clustering in the solution. The spin-counting and distance measurements by DEER-ESR provide further evidence that peptides are dispersed homogeneously in mesopores but heterogeneously in vitrified solvents wherein the biomolecular structure is disturbed due to heterogeneity in the bulk solvent structure. Our study demonstrates that the nanospace within mesoporous materials provides an amorphous environment that is better than vitrified bulk solvent for studying biostructures at cryogenic temperatures.
Abstract-Limited studies have examined the effects of nonsteroidal anti-inflammatory drug (NSAID) use on the risk of chronic kidney disease (CKD), especially in subjects with hypertension. Using National Health Insurance claims data in Taiwan, we conducted a propensity score-matched cohort study to investigate the relationship between NSAID use and CKD in subjects with hypertension. A total of 31 976 subjects were included in this study: subjects not taking any NSAIDs in 2007 (n=10 782); subjects taking NSAIDs for 1 to 89 days in 2007 (n=10 605); and subjects taking NSAIDs for ≥90 days in 2007 (n=10 589). We performed multivariable proportional hazard models to determine the relationship between NSAID use and CKD. The results showed that NSAID use was associated with a 1.18-fold increased risk of CKD in subjects taking NSAIDs for 1 to 89 days; and a 1.32-fold increased risk of CKD in hypertension subjects taking NSAIDs for ≥90 days, compared with subjects not taking any NSAIDs, after controlling for the confounding factors. In subgroup analyses, subjects taking NSAIDs for ≥90 days, >1 defined daily dose per day or taking NSAIDs >15 cumulative defined daily doses had a greater risk of CKD than subjects not taking any NSAID, but not for congestive heart failure, stroke, cancer, osteoarthritis, or rheumatoid arthritis. These results provide supportive evidence that NSAID use is associated with increased risk of CKD in subjects with hypertension. It is important to closely monitor the effects of NSAID use, particularly in patients with hypertension, a susceptible population for CKD.
The results demonstrated an increased risk of VTE among subjects with current antipsychotic use. Antipsychotic drugs should be prescribed with caution and attention to the increased risk of VTE. The underlying mechanisms related to the effect of antipsychotics on VTE development warrant further investigation.
Sinonasal SH is a rare diagnosis characterized by a polypoid lesion with a haphazard proliferation of seromucinous glands. The rhinologists should consider it in the differential diagnosis of a polypoid lesion in the nasal cavity.
Nanochannels of mesoporous silica materials were previously found useful for reducing the tumbling motion of encapsulated biomolecules while leaving the biomolecular structure undisturbed. Here we show that experiments of cw-ESR distance measurement in nano-confinement can benefit immediately from the above mentioned features of sufficiently slow molecular tumbling, enabling more accurate determination of interspin distances throughout the temperature range, from 200 to 300 K. A 26-residue prion protein peptide, which can fold into either a helical or hairpin structure, as well as its variants, are studied by using ESR. By comparing the spectra obtained in vitrified bulk solutions vs. mesopores, the spectra from the latter display typical slow-motional lineshapes, thereby enabling dipolar anisotropy to be unambiguously revealed throughout the temperature range, whereas the spectra from the former are dominated by the disordering of the side chain and the rotational tumbling of the peptide. The spectral changes regarding the two secondary structures in nano-confinement are found to show a strong correlation with the dynamic properties of the backbones. The effect of viscosity agent perturbation on the motion of an R1 nitroxide side chain, a commonly employed probe, could be substantial in a bulk solution condition, though it is absolutely absent in nanochannels. Under nano-confinement, the probe is proven sufficiently sensitive to the backbone motions. Overall, the distance distributions determined from the mesopore studies not only describe the conformational structures (by average distances), but also the backbone dynamics (by distribution widths) of the spin-labeled peptides.
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