The spatial structure and temporal evolution of the sea surface temperature (SST) anomaly (SSTA) associated with the passage of tropical cyclones (TCs), as well as their sensitivity to TC ...characteristics (including TC intensity and translation speed) and oceanic climatological conditions (represented here by latitude), are thoroughly examined by means of composite analysis using satellite-derived SST data. The magnitude of the TC-generated SSTA is larger for more intense, slower-moving, and higher-latitude TCs, and it occurs earlier in time for faster-moving and higher-latitude storms. The location of maximum SSTA is farther off the TC track for faster-moving storms, and it moves toward the track with time after the TC passage. The spatial extension of the cold wake is greater for more intense and for slower-moving storms, but its shape is quite independent of TC characteristics. Consistent with previous studies, the calculations show that the mean SSTA over a TC-centered box nearly linearly correlates with the wind speed for TCs below category 3 intensity while for stronger TCs the SSTA levels off, both for tropical and subtropical regions. While the linear behavior is expected on the basis of the more vigorous mixing induced by stronger winds and is derived from a simple mixed-layer model, the level-off for intense TCs is discussed in terms of the dependence of the maximum amplitude of the area-mean SSTA on TC translation speed and depth of the prestorm mixed layer. Finally, the decay time scale of the TC-induced SSTA is shown to be dominated by environmental conditions and has no clear dependence on its initial magnitude and on TC characteristics.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hydroxyapatite (HA) reinforced collagen fibrils serve as the basic building blocks of natural bone and dentin. Mineralization of collagen fibrils play an essential role in ensuring the structural and ...mechanical functionalities of hard tissues such as bone and dentin. Biomineralization of collagen can be divided into intrafibrillar and extrafibrillar mineralization in terms of HA distribution relative to collagen fibrils. Intrafibrillar mineralization is termed when HA minerals are incorporated within the gap zone of collagen fibrils, while extrafibrillar mineralization refers to the minerals that are formed on the surface of collagen fibrils. However, the mechanisms resulting in these two types of mineralization still remain debatable. In this review, the evolution of both classical and non-classical biomineralization theories is summarized. Different intrafibrillar mineralization mechanisms, including polymer induced liquid precursor (PILP), capillary action, electrostatic attraction, size exclusion, Gibbs-Donnan equilibrium, and interfacial energy guided theories, are discussed. Exemplary strategies to induce biomimetic intrafibrillar mineralization using non-collagenous proteins (NCPs), polymer analogs, small molecules, and fluidic shear stress are discussed, and recent applications of mineralized collagen fibers for bone regeneration and dentin repair are included. Finally, conclusions are drawn on these proposed mechanisms, and the future trend of collagen-based materials for bone regeneration and tooth repair is speculated.
Dichotomy between local spins and conjugated electrons spawns various exotic physical phenomena, however, it has mostly been reported in three-dimensional (3D) inorganic systems. We show, for the ...first time, that a rare 2D metal-organic framework exhibits intriguing dichotomy behavior, which can be directly identified through scanning tunneling microscopy/spectroscopy (STM/STS). In a newly synthesized Cu-hexaiminobenzene Cu3(HAB)2, on the one hand, the Cu2+ ions form an ideal S - 1/2 antiferromagnetic (AFM) kagome lattice; on the other hand, the conjugated-electrons from the organic ligands produce a frustrated πx,y model on a honeycomb lattice, giving rise to completely dispersionless energy bands around the Fermi level that favour the ferromagnetic (FM) state. Remarkably, the frustrated local spins and conjugated electrons interact through a strong FM Hund's coupling, giving rise to a wide range of intriguing quantum phases. Furthermore, we propose that this dichotomy can be directly characterized through STM/STS measurements due to its special 2D nature, which provides a unique exciting platform to investigate the dichotomy of frustrated spins and electrons in a single lattice.
Multidimensional fabrication of metal–organic frameworks (MOFs) into multilevel channel integrated devices are in high demanded for Li‐S separators. Such separators have advantages in ...pore‐engineering that might fulfill requirements such as intercepting the diffusing polysulfides and improving the Li+/electrolyte transfer in Li‐S batteries. However, most reported works focus on the roles of MOFs as ionic sieves for polysulfides while offering limited investigation on the tuning of Li+ transfer across the separators. A photoinduced heat‐assisted processing strategy is proposed to fabricate MOFs into multidimensional devices (e.g., hollow/Janus fibers, double‐or triple‐layer membranes). For the first time, a triple‐layer separator with stepped‐channels has been designed and demonstrated as a powerful separator with outstanding specific capacity (1365.0 mAh g−1) and cycling performance (0.03 % fading per cycle from 100th to 700th cycle), which is superior to single/double‐layer and commercial separators. The findings may expedite the development of MOF‐based membranes and extend the scope of MOFs in energy‐storage technologies.
A two‐step photoinduced heat‐assisted processing (PHAP) method is proposed to fabricate a kind of metal–organic framework (MOF)‐based triple‐layer membrane with stepped channels. The membrane can be applied as a high performance separator in a lithium–sulfur battery.
We show that a suitable combination of geometric frustration, ferromagnetism, and spin-orbit interactions can give rise to nearly flatbands with a large band gap and nonzero Chern number. Partial ...filling of the flatband can give rise to fractional quantum Hall states at high temperatures (maybe even room temperature). While the identification of material candidates with suitable parameters remains open, our work indicates intriguing directions for exploration and synthesis.
Warm‐temperate evergreen (WTE) forest represents the typical vegetation type of subtropical China, but how its component species responded to past environmental change remains largely unknown. Here, ...we reconstruct the evolutionary history of Tetrastigma hemsleyanum, an herbaceous climber restricted to the WTE forest. Twenty populations were genotyped using chloroplast DNA sequences and nuclear microsatellite loci to assess population structure and diversity, supplemented by phylogenetic dating, ancestral area reconstructions and ecological niche modeling (ENM) of the species distributions during the Last Glacial Maximum (LGM) and at present. Lineages in Southwest vs Central‐South‐East China diverged through climate/tectonic‐induced vicariance of an ancestral southern range during the early Pliocene. Long‐term stability in the Southwest contrasts with latitudinal range shifts in the Central‐South‐East region during the early‐to‐mid‐Pleistocene. Genetic and ENM data strongly suggest refugial persistence in situ at the LGM. Pre‐Quaternary environmental changes appear to have had a persistent influence on the population genetic structure of this subtropical WTE forest species. Our findings suggest relative demographic stability of this biome in China over the last glacial–interglacial cycle, in contrast with palaeobiome reconstructions showing that this forest biome retreated to areas of today's tropical South China during the LGM.
Cadmium (Cd) is a widespread environmental pollutant that accumulates in living systems and represents a significant global health hazard. Cd poses a toxicity threat to both human and animal health, ...including that of birds. Further knowledge of Cd toxicology pathways will allow for a better understanding of Cd-induced nephrotoxicity. To evaluate Cd-induced nephrotoxicity through potential oxidative damage, male chickens were treated with 0 mg/kg, 35 mg/kg or 70 mg/kg CdCl2 in diet for 90 days. Markedly, histopathology indicated renal tubular epithelial cell swelling, renal function CREA content abnormalities, biochemical and morphologic indices indicative of Cd-induced kidney injury. Cd toxicity induced the up-regulation of Nrf2 and downstream target genes that relieve oxidative stress. Meanwhile, Cd disrupted the homeostasis of trace elements and promoted oxidative damage. Cd interfered with mitochondrial unfolded protein response (UPRmt)-related factors (SIRT1, SIRT3, PGC-1α, TFAM, Nrf1, and HTRA2) and disrupted the homeostasis of mitochondrial dynamics (OPA1, MFN1, MFN2, Fis1 and MFF), thereby exacerbating mitochondrial structural damage and mitochondrial dysfunction. In conclusion, our study demonstrated that the nephrotoxicity of Cd exposure results in oxidative stress and mitochondrial dysfunction by activating the Nrf2 signaling pathway and inhibiting UPRmt in the kidneys.
Cadmium (Cd) is a widespread environmental pollutant that accumulates in living systems and exerts significant global health hazards. Cd enters the kidney through cell membranes and disrupts the metabolic system, ultimately resulting in nephrotoxicity. Our findings provide new evidence that Cd exposure affects the regulation of the UPRmt and the Nrf2-mediated antioxidant response in the kidney. Display omitted
•Cadmium exposure caused nephrotoxicity.•Cadmium disturbed the homeostasis of trace elements in kidney.•Cadmium induced oxidative stress via affecting Nrf2 mediated antioxidant defense.•Cadmium induced mitochondrial injury via inhibition of mitochondrial UPR.
Sequencing of DNase I hypersensitive sites (DNase-seq) is a powerful technique for identifying cis-regulatory elements across the genome. We studied the key experimental parameters to optimize ...performance of DNase-seq. Sequencing short fragments of 50-100 base pairs (bp) that accumulate in long internucleosome linker regions was more efficient for identifying transcription factor binding sites compared to sequencing longer fragments. We also assessed the potential of DNase-seq to predict transcription factor occupancy via generation of nucleotide-resolution transcription factor footprints. In modeling the sequence-specific DNase I cutting bias, we found a strong effect that varied over more than two orders of magnitude. This indicates that the nucleotide-resolution cleavage patterns at many transcription factor binding sites are derived from intrinsic DNase I cleavage bias rather than from specific protein-DNA interactions. In contrast, quantitative comparison of DNase I hypersensitivity between states can predict transcription factor occupancy associated with particular biological perturbations.
Cadmium (Cd) is a toxic pollutant with high nephrotoxicity in the agricultural environment. Resveratrol has been found to have a renoprotective effect but the underlying mechanisms of this have not ...yet been fully elucidated. The aim of this study is to illustrate the antagonism of resveratrol against Cd-induced nephrotoxicity. A total of 80 birds were divided randomly into 4 groups and treated via diet for 90 days as follows: control group (Con); 400 mg kg-1 resveratrol group (Resv); 140 mg kg-1 Cd group (Cd 140); and 140 mg kg-1 Cd + 400 mg kg-1 resveratrol group (Cd + Resv). It was observed that resveratrol treatment dramatically alleviated Cd-induced histopathological lesions of the kidney. Simultaneously, resveratrol mitigated Cd-induced oxidative stress by reducing MDA and H2O2 production, alleviating GSH depletion and restoring the activity of antioxidant enzymes (T-SOD, Cu-Zn SOD, CAT, GST and GSH-Px). Resveratrol activated NXRs (CAR/PXR/AHR/Nrf2) signaling pathways and exerted antidotal roles by enhancing the phase I and II detoxification systems to relieve oxidative damage. Moreover, resveratrol ameliorated Cd-induced ultrastructural abnormality and mitochondria dysfunction by recovering mitochondrial function-related factors VDAC1, Cyt C and Sirt3 upregulation and Sirt1, PGC-1α, Nrf1 and TFAM transcription restrictions. Resveratrol attenuated Cd-induced excessive mitochondrial fission and promoted mitochondrial fusion, which reversed PINK1/Parkin-mediated mitophagy initiation. Collectively, our findings explicate the potential protection against Cd-induced nephrotoxicity and mitochondria damage.
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