The sirtuin 6 (SIRT6) participates in regulating glucose and lipid homeostasis. However, the function of SIRT6 in the process of cardiac pathogenesis caused by obesity-associated lipotoxicity remains ...to be unveiled. This study was designed to elucidate the role of SIRT6 in the pathogenesis of cardiac injury due to nutrition overload-induced obesity and explore the downstream signaling pathways affecting oxidative stress in the heart. In this study, we used
Sirt6 cardiac-specific
knockout murine models treated with a high-fat diet (HFD) feeding to explore the function and mechanism of SIRT6 in the heart tissue during HFD-induced obesity. We also took advantage of neonatal cardiomyocytes to study the role and downstream molecules of SIRT6 during HFD-induced injury in vitro, in which intracellular oxidative stress and mitochondrial content were assessed. We observed that during HFD-induced obesity,
Sirt6
loss-of-function aggravated cardiac injury including left ventricular hypertrophy and lipid accumulation. Our results evidenced that upon increased fatty acid uptake, SIRT6 positively regulated the expression of endonuclease G (ENDOG), which is a mitochondrial-resident molecule that plays an important role in mitochondrial biogenesis and redox homeostasis. Our results also showed that SIRT6 positively regulated superoxide dismutase 2 (SOD2) expression post-transcriptionally via ENDOG. Our study gives a new sight into SIRT6 beneficial role in mitochondrial biogenesis of cardiomyocytes. Our data also show that SIRT6 is required to reduce intracellular oxidative stress in the heart triggered by high-fat diet-induced obesity, involving the control of ENDOG/SOD2.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Skeletal muscle is responsible for the majority of glucose disposal in the body. Insulin resistance in the skeletal muscle accounts for 85-90% of the impairment of total glucose disposal in patients ...with type 2 diabetes (T2D). However, the mechanism remains controversial. The present study aims to investigate whether AKT2 deficiency causes deficits in skeletal muscle development and metabolism, we analyzed the expression of molecules related to skeletal muscle development, glucose uptake and metabolism in mice of 3- and 8-months old. We found that AMP-activated protein kinase (AMPK) phosphorylation and myocyte enhancer factor 2 (MEF2) A (MEF2A) expression were down-regulated in AKT2 knockout (KO) mice, which can be inverted by AMPK activation. We also observed reduced mitochondrial DNA (mtDNA) abundance and reduced expression of genes involved in mitochondrial biogenesis in the skeletal muscle of AKT2 KO mice, which was prevented by AMPK activation. Moreover, AKT2 KO mice exhibited impaired AMPK signaling in response to insulin stimulation compared with WT mice. Our study establishes a new and important function of AKT2 in regulating skeletal muscle development and glucose metabolism via AMPK-dependent signaling.
In this work, full‐color and stable white organic afterglow materials with outstanding water, organic solvents, and temperature resistances have been developed for the first time by embedding the ...selected polycyclic aromatic hydrocarbons into melamine‐formaldehyde polymer via solution polymerization. The afterglow quantum yields and lifetimes of the resulting polymer films were up to 22.7 % and 4.83 s, respectively, under ambient conditions. For the coronene‐doped sample, its afterglow color could be linearly tuned between yellow and blue by adjusting the temperature, and it could still emit an intense blue afterglow with a lifetime of 0.68 s at 440 K. Moreover, the films showed a bright and stable white afterglow at 370 K with a lifetime of 2.80 s and maintained an excellent afterglow performance after soaking in water and organic solvents for more than 150 days. In addition, the application potential of the polymer films in information encryption and anti‐counterfeiting was also demonstrated.
Full‐color and stable white organic afterglow materials have been developed by embedding the selected polycyclic aromatic hydrocarbons into a melamine‐formaldehyde polymer by solution polymerization. Their afterglow quantum yields and lifetimes were up to 22.7 % and 4.83 s, respectively. Moreover, the resulting polymer films showed a color‐tunable dual‐mode organic afterglow and outstanding water, organic solvents, and temperature resistances.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Bioimaging at a subcellular resolution to label cytoplasm and nucleus in living cell by just one photoluminescent nanoparticle has great application potential in bioresearch, preclinical diagnosis, ...screening, and image-guided therapy of life-threatening diseases. Herein, we report a novel arginine (Arg) functionalized ultra-small lanthanide oxyfluoride nanocrystals (LaOF) for simultaneously targeted imaging cell cytoplasm and nucleus. As-prepared Arg-modified PAA capped LaOF: 45%Ce, 15%Tb nanocrystals (LaOF:Ce,Tb@PAA@Arg) possessed high water dispersibility, ultra-small size (∼5.7 nm) and double emissions (green and red) with high quantum yield (40%). Such functionalized nanocrystals presented high cellular biocompatibility and were successfully used to label living cells with very high contrast. These functionalized nanocrystals also exhibited significantly higher photostability and brightness as compared to commercial dyes. Such the ultra-small size, high photostability and intensity, double emissions, excellent biocompatibility and targeted ability, make as-prepared functionalized nanocrystals particularly promising for cellular and subcellular bioimaging applications.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
The railway station is a representative kind of large space building, whose air-conditioning system design has always been paid a lot of attentions. At present, the air-conditioning system at a train ...station is mainly a stratified air conditioning mode with spout air supply outlets, which has a significant thermal stratification and energy waste in winter. In this paper, a large space waiting room of one railway station in Wuhan is taken as the analysis example, and the CFD method is used to simulate the airflow and temperature distribution under different air-conditioning terminal devices in winter and summer. The airflow organization models of the waiting hall under three typical air-conditioning systems have been established including stratified air conditioning system, air handling unit special for large space system and floor radiation system. The temperature and velocity distributions of the large space in the waiting hall are comparatively simulated under each system. The temperature stratification, the amount of cooling and heating requirements are obtained for three types of air conditioning systems. According to minimum amount of the annual cooling and heating loads, a terminal device form of air-conditioning system which is suitable for large space is provided. The results can provide a reference for the design of air-conditioning systems for similar large space buildings.
In this work, an efficient polymer‐based organic afterglow system, which shows reversible photochromism, switchable ultralong organic phosphorescence (UOP), and prominent water and chemical ...resistance simultaneously, has been developed for the first time. By doping phenoxazine (PXZ) and 10‐ethyl‐10H‐phenoxazine (PXZEt) into epoxy polymers, the resulting PXZ@EP‐0.25 % and PXZEt@EP‐0.25 % films show unique photoactivated UOP properties, with phosphorescence quantum yields and lifetimes up to 10.8 % and 845 ms, respectively. It is found that the steady‐state luminescence and UOP of PXZ@EP‐0.25 % are switchable by light irradiation and thermal annealing. Moreover, the doped films can still produce conspicuous UOP after soaking in water, strong acid and base, and organic solvents for more than two weeks, exhibiting outstanding water and chemical resistance. Inspired by these exciting results, the PXZ@EP‐0.25 % has been successfully exploited as an erasable transparent film for light printing.
A series of efficient phosphorescence materials were developed by embedding phenothiazine, phenoxazine, and 10‐ethyl‐10H‐phenoxazine into epoxy polymers. It is found that the polymer film involving phenoxazine shows reversible photochromism, switchable ultralong organic phosphorescence, and prominent water and chemical resistance simultaneously. In addition, its potential application in erasable light printing has also been demonstrated.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Unlike most Precambrian cratons that have thick sub-continental lithospheric roots,the Archean lithosphere beneath the North China Craton is thin （reduced from 200 km to about 80 km）,and has been ...replaced by a geochemically juvenile lithospheric mantle.This is a unique regional geological event,which has attracted worldwide attention.In the North China Block,Late Mesozoic extensional tectonics is evident by low-angle detachment faults,syntectonic plutons bounded by ductile faults,metamorphic core complexes （MCC） and widespread Jurassic to Cretaceous half-grabens filled by continental terrigenous deposits and volcanic rocks.At a regional scale,these structures share the same NW-SE extensional direction,while maintaining their own individual kinematics.In other words,the MCC feature a top-to-the-NW sense of shear,and syntectonic plutons are typified by a top-to-the-SE shearing deformations.Geochronological results indicate that the extensional structures were formed between 130-120 Ma.These extensional events lead to magmatic rock emplacement,distributed at the footwall of the detachment faults.Two different exhumation stages can be identified based on regional structural and magmatic interpretation：a Jurassic slow or negligible exhumation and a Cretaceous fast one assisted by normal faulting.These two cooling stages correspond to distinct geodynamic processes that occurred during the Jurassic and Cretaceous.Extensional tectonics appear to have been insignificant before the Early Cretaceous,and the process may be demonstrated by partial melting of the crust.The second stage,dominated by an extensional regime,developed after ca 120 Ma,and is tentatively correlated with crustal extension caused by lithospheric removal of the North China Craton.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Extensive organic-matter （OM） rich facies （black shales） occur in the Ordo-Silurian boundary successions in the Yangtze area, South China. To investigate the redox changes of the Yangtze Sea during ...the Ordo-Silurian transition, two OM sections （Wangjiawan in Yichang, Hubei Province, and Sanjiaguan in Zhangjiajie, Hunan Province） straddling the Ordo-Silurian boundary are studied. The measurements finished in this study include contents of the total organic carbon （TOC）, pyrite sulphur, and different species of Fe, including dithionite-extractable Fe （FED）, pyrite Fe （FeP）, HCl-extractable Fe （FeH）, and total Fe （FeT）, in black shales, as well as other redox proxies, such as the SIC ratio, the ratio between highly reactive Fe （FeHR = FeD ＋ FeP） and FeT, and the FeP/（FeP ＋ FeH） ratio, known as the degree of pyritization （DOP）. In the Wangjiawan section, the Middle Ashgill sediments have high FeHR/FeT ratios （0.20-0.77; avg. 0.45）, high DOP values （0.21-0.72; avg. 0.54）, and a relatively constant sulfur content independent of the organic carbon content. By the contrast, the mid-early Hirnantian deposits generally have low FeHR/FeT ratios （0.10-0.35; avg. 0.21）, low DOP values （0.11- 0.40; avg. 0.28）, and SIC values are clustering on the normal marine value （SIC = 0.36）. The late Hirnantian and early Rhuddanian deposits, similar to those of the Middle Ashgill deposits, are characterized by high FeHR/FeT ratios （0.32-0.49; avg. 0.41）, high DOP values （0.46-0.68; avg. 0.53） and fairly constant sulfur contents. These data suggest the occurrences of marine anoxia on the Yangtze Sea shelf during intervals of the Mid Ashgill, Late Hirnantian and Early Rhuddanian, and ventilated and oxygenated marine conditions during the mid-early Hirnantian time. The mid-early Hirnantian ventilated event was concomitant with the global glacial period, likely resulted from the glacio-eustatic sea-level fall and subsequent circulation of cold, dense oxygenated waters upon the shelf seabed. Accordingly, the abrupt change from oxygenated to anoxic marine waters from the late Hirnantian and the early Rhuddanian were resulted from the post-glacial rise of eustatic sea level. Combined with the data from Sanjiaguan section near the subemergent highland, salinity stratification of water columns are strongly evidenced by very low S/C ratios （ 0.00-0.08, avg. 0.02）, low FeHR/FeT ratios （0.10-0.37, avg. 0.27）, low DOP values （0.01-0.27, avg. 0.10）, and TOC contents （0.72%-4.27%, avg. 2.55%）. Under this circumstance, the anoxic water columns could have formed beneath the halocline, above which desalinized waters formed. In the Wangjiawan section, TOC contents are generally high （0.94- 9.32%, avg. 4.44%）, but low （0.35%-2.12%, avg. 1.29%） in the mid-early Hirnantian that is coincident with the oceanic oxic stage, together with relation of the organic contents to the stratal thickness, suggesting that the accumulation of the organic matter was mainly controlled by the oxygen levels of the water columns; on the other hand, productivity and depositional rate may also have played a role in the organic accumulation and preservation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Based on the data at~40°N at different longitudes during different stratospheric sudden warming（SSW）events,the responses of zonal winds in the stratosphere,mesosphere and lower thermosphere to SSWs ...are studied in this paper.The variations of zonal wind over Langfang,China（39.4°N,116.7°E）by MF radar and the modern era retrospective-analysis for research and applications（MERRA）wind data during 2010 and 2013 SSW and over Fort Collins,USA（41°N,105°W）by lidar and MERRA wind data during 2009 SSW are compared.Results show that the zonal wind at~40°N indeed respond to the SSWs while different specifics are found in different SSW events or at different locations.The zonal wind has significant anomalies during the SSWs.Over Langfang,before the onset of 2010 and 2013 SSW,the zonal wind reverses from eastward to westward below about 60–70 km and accelerates above this region,while westward wind prevails from 30 to 100 km after the onset of2010 SSW,and westward wind prevails in 30–60 and 85–100 km and eastward wind prevails in 60–85 km after the onset of2013 SSW.Over Fort Collins during 2009 SSW,eastward wind reverses to westward in 20–30 km before the onset while westward wind prevails in 20–30 and 60–97 km and eastward wind prevails in 30–60 and in 97–100 km after the onset.Moreover,simulations by the specified dynamics version of the whole atmosphere community climate model（SD-WACCM）are taken to explain different responding specifics of zonal wind to SSW events.It is found that the modulation of planetary wave（PW）plays the main role.Different phases of PWs would lead to the different zonal wind along with longitudes and the different amplitudes and phases in different SSW events can lead to the different zonal wind responses.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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