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An inverse sandwich structure has been computationally predicted for uranium boride and extended to the series of actinide elements (An) from Th to Cm. The electronic structure and chemical bonding of these novel compounds have been analyzed using density functional theory and multireference wave-function based methods. We report the trends in electronic structure and bonding for An2B8, and found that (d-π)π and (d-p)δ are the most important factors in the stability of An2B8. The (f-p)δ bond provides extra stabilization for Pa2B8 and U2B8, owing to the extensive interactions of An-B8-An, resulting in a short distance for the Pa-Pa and U-U bonds.
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This research aimed to clarify the effects of exogenously applied chitosan on the physiological characteristics, antioxidant activities, and Cd accumulation of wheat (Triticum aestivum L.) seedlings under cadmium (Cd) stress and to identify the key indicators based on the partial least squares model. The wheat variety studied was Bainong207 (BN207), and Cd-stress was achieved by growing seedlings in a hydroponic culture experiment with 10 and 25 µmol·L-1 Cd2+ added to the culture solution. It was found that both Cd-stress at 10 and 25 µmol·L-1 significantly inhibited the chlorophyll content, photosynthesis, and biomass accumulation of wheat seedlings. Seedling roots became shorter and thicker, and the lateral roots decreased under Cd-stress. The Cd-stress also increased H2O2 and MDA accumulation and the degree of cell membrane lipid peroxidation and affected the activities of antioxidant enzymes such as superoxide dismutase (SOD) and peroxidase (POD). Under Cd stress, exogenous chitosan decreased the Cd content in the aboveground and underground parts of wheat by 13.22 %-21.63 % and 7.92 %-28.32 % and reduced Cd accumulation in the aboveground and underground parts by 5.37 %-6.71 % and 1.91 %-4.09 %, respectively. Whereas exogenous chitosan application significantly reduced the content of H2O2 in roots and aboveground parts of wheat by 38.21 %-47.46 % and 45.81 %-55.73 % and MDA content by 37.65 %-48.12 % and 29.87 %-32.51 %, it increased the activities of SOD and POD in roots by 2.78 %-5.61 % and 13.81 %-18.33 %, respectively. In summary, exogenous chitosan can improve the photosynthetic characteristics and antioxidant enzyme activities of wheat seedlings under Cd stress, reduce the content and accumulation of Cd in the root and aboveground parts of wheat, and alleviate the damage of lipid peroxidation to the cell membrane. All of these results provide the basal data for the application of exogenous chitosan to alleviate Cd toxicity to wheat seedlings.
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Antioxidantes , Cadmio , Quitosano , Plantones , Triticum , Triticum/metabolismo , Triticum/efectos de los fármacos , Triticum/crecimiento & desarrollo , Cadmio/toxicidad , Cadmio/metabolismo , Quitosano/metabolismo , Quitosano/farmacología , Plantones/efectos de los fármacos , Plantones/metabolismo , Antioxidantes/metabolismo , Estrés Fisiológico/efectos de los fármacos , Superóxido Dismutasa/metabolismo , Contaminantes del Suelo/toxicidad , Contaminantes del Suelo/metabolismoRESUMEN
The deteriorated plasticity arising from the insoluble precipitates may lead to cracks during the rolling of FeCrAl alloys. The microstructure evolution and hot deformation behavior of an FeCrAl alloy were investigated in the temperature range of 750-1200 °C and strain rate range of 0.01-10 s-1. The flow stress of the FeCrAl alloy decreased with an increasing deformation temperature and decreased strain rate during hot working. The thermal deformation activation energy was determined to be 329.49 kJ/mol based on the compression test. Then, the optimal hot working range was given based on the established hot processing maps. The hot processing map revealed four small instability zones. The optimal working range for the material was identified as follows: at a true strain of 0.69, the deformation temperature should be 1050-1200 °C, and the strain rate should be 0.01-0.4 s-1. The observation of key samples of thermally simulated compression showed that discontinuous dynamic recrystallization started to occur with the temperate above 1000 °C, leading to bended grain boundaries. When the temperature was increased to 1150 °C, the dynamic recrystallization resulted in a microstructure composed of fine and equiaxed grains.
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Background: DHEA is a steroid hormone produced by the gonads, adrenal cortex, brain, and gastrointestinal tract. While the anti-obesity, anti-atherosclerosis, anti-cancer, and memory-enhancing effects of DHEA have been substantiated through cell experiments, animal studies, and human trials, the precise mechanisms underlying these effects remain unclear. Altered mitochondrial dynamics can lead to mitochondrial dysfunction, which is closely related to many human diseases, especially cancer and aging. This study was to investigate whether DHEA inhibits lung adenocarcinoma through the mitochondrial pathway and its molecular mechanism. Methods: Through animal experiments and cell experiments, the effect of DHEA on tumor inhibition was determined. The correlation between FASTKD2 expression and DHEA was analyzed by Western blot, Reverse transcription-quantitative PCR, Immunohistochemistry, and TCGA database. Results: In this study, DHEA supplementation in the diet can inhibit the tumor size of mice, and the effect of adding DHEA one week before the experiment is the best. DHEA limits the glycolysis process by inhibiting G6PDH activity, increases the accumulation of reactive oxygen species, and initiates apoptosis in the mitochondrial pathway of cancer cells. Conclusion: DHEA suppresses mitochondrial fission and promotes mitochondrial fusion by downregulating the expression of FASTKD2, thereby inhibiting tumor growth and prolonging the overall survival of lung adenocarcinoma patients, which also provides a new target for the prevention and treatment of lung adenocarcinoma.
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This research aimed to clarify the mitigative effect of exogenously applied rare earth element cerium ï¼Ceï¼ on the growthï¼ zinc ï¼Znï¼ accumulationï¼ and physiological characteristics of wheat ï¼Triticum aestivum L.ï¼ seedlings under Zn stress. The wheat variety studied was Bainong307 ï¼BN307ï¼ï¼ and Zn stress was achieved by growing seedlings in a hydroponic culture experiment with 500 µmol·L-1 Zn2 + added to the culture solution. It was found that Zn stress at 500 µmol·L-1 significantly inhibited the chlorophyll contentï¼ photosynthesisï¼ and biomass accumulation of wheat seedlings. Seedling roots became shorter and thickerï¼ and the lateral roots decreased under Zn stress. The Zn stress also increased MDA accumulation and the degree of cell membrane lipid peroxidation and reduced soluble protein contents and the activities of antioxidant enzymes such as superoxide dismutase ï¼SODï¼ï¼ catalase ï¼CATï¼ï¼ and ascorbate peroxidase ï¼APXï¼. On the contraryï¼ exogenous Ce decreased the adsorption and transport of Zn by the root system and alleviated the damage of Zn stress to wheat seedlings. Specificallyï¼ the increase in chlorophyll content ï¼chlorophyll aï¼ chlorophyll bï¼ and total chlorophyllï¼ and photosynthetic parametersï¼ the enhancement of antioxidant enzymes activities and soluble protein levelsï¼ and the reduction in MDA content and the damage of lipid peroxidation to the cell membrane were all driven by exogenous Ceï¼ which ultimately led to the increase in dry matter biomass of the root system and shoot. In summaryï¼ these results provide basic data for the application of exogenous Ce to alleviate Zn toxicity to plants.
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Cerio , Zinc , Zinc/metabolismo , Antioxidantes/metabolismo , Plantones , Triticum , Cerio/metabolismo , Cerio/farmacología , Clorofila A , Superóxido Dismutasa/metabolismo , Clorofila , Estrés OxidativoRESUMEN
To explore the effects of different concentrations of zinc ï¼Znï¼ on the growth and root architecture classification of maize seedlings under cadmium ï¼Cdï¼ stressï¼ a hydroponic experiment was conducted to study the effects of different concentrations of Zn ï¼0ï¼ 10ï¼ 25ï¼ 50ï¼ 100ï¼ 200ï¼ and 400 µmol·L-1ï¼ on the growthï¼ root architecture and classification characteristicsï¼ Cd contentï¼ root Cd uptake capacityï¼ and photosynthetic system of maize seedlings under Cd stress ï¼50 µmol·L-1ï¼ by using Zhengdan 958 as the experimental material. Principal component analysis and the membership function method were used for comprehensive evaluation. The results showed that the 50 µmol·L-1 Cd stress had a significant toxic effect on maize seedlingsï¼ which significantly reduced chlorophyll content and photosynthetic parameters. The main root lengthï¼ plant heightï¼ biomassï¼ root forksï¼ and root tipsï¼ including the root length and root surface area of the grade â -â ¢ diameter range and the root volume of the grade â -â ¡ diameter rangeï¼ decreased significantlyï¼ which hindered the normal growth and development of maize seedlings. Compared with that under no Zn applicationï¼ 100 µmol·L-1 and 200 µmol·L-1 Zn application reduced the uptake of Cd by maize seedlingsï¼ significantly reduced the Cd content in shoots and roots and the Cd uptake efficiency. The toxic effect on maize seedlings was alleviatedï¼ and the fresh weightï¼ dry weightï¼ tolerance indexï¼ and root forks of shoots and roots were significantly increased. The photosynthesis of maize seedlings was significantly enhancedï¼ and the photosynthetic rate and the total chlorophyll content was significantly increased. The RLï¼ SAï¼ and RV in the â -â ¡ diameter range reached the maximum at 100 µmol·L-1 Znï¼ and the RLï¼ SAï¼ and RV in the â ¢ diameter range reached the maximum at 200 µmol·L-1 Znï¼ which were significantly higher than those without Zn treatment. The comprehensive evaluation of the growth tolerance of maize seedlings showed that 100 µmol·L-1 and 200 µmol·L-1 Zn had better effects on alleviating Cd toxicity. Comprehensive analysis showed that the application of appropriate concentration of Zn could reduce the Cd content in maize seedlingsï¼ the Cd uptake capacityï¼ and Cd uptake efficiency of rootsï¼ increase the biomass accumulation of maize seedlingsï¼ reduce the effect of Cd toxicity on root architectureï¼ reduce the effect on the light and systemï¼ and improve the tolerance of maize seedlings to Cd.
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Plantones , Contaminantes del Suelo , Zinc , Cadmio , Zea mays , Raíces de Plantas , ClorofilaRESUMEN
The 18O enrichment (Δ18O) of cellulose (Δ18OCel) is recognized as a unique archive of past climate and plant function. However, there is still uncertainty regarding the proportion of oxygen in cellulose (pex) that exchanges post-photosynthetically with medium water of cellulose synthesis. Particularly, recent research with C3 grasses demonstrated that the Δ18O of leaf sucrose (Δ18OSuc, the parent substrate for cellulose synthesis) can be much higher than predicted from daytime Δ18O of leaf water (Δ18OLW), which could alter conclusions on photosynthetic versus post-photosynthetic effects on Δ18OCel via pex. Here, we assessed pex in leaves of perennial ryegrass (Lolium perenne) grown at different atmospheric relative humidity (RH) and CO2 levels, by determinations of Δ18OCel in leaves, Δ18OLGDZW (the Δ18O of water in the leaf growth-and-differentiation zone) and both Δ18OSuc and Δ18OLW (adjusted for εbio, the biosynthetic fractionation between water and carbohydrates) as alternative proxies for the substrate for cellulose synthesis. Δ18OLGDZW was always close to irrigation water, and pex was similar (0.53 ± 0.02 SE) across environments when determinations were based on Δ18OSuc. Conversely, pex was erroneously and variably underestimated (range 0.02-0.44) when based on Δ18OLW. The photosynthetic signal fraction in Δ18OCel is much more constant than hitherto assumed, encouraging leaf physiological reconstructions.
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Dióxido de Carbono , Celulosa , Humedad , Isótopos de Oxígeno , Hojas de la Planta , Sacarosa , Hojas de la Planta/metabolismo , Celulosa/metabolismo , Dióxido de Carbono/metabolismo , Sacarosa/metabolismo , Isótopos de Oxígeno/metabolismo , Lolium/metabolismo , Lolium/crecimiento & desarrollo , Lolium/fisiología , Atmósfera , Fotosíntesis , Agua/metabolismoRESUMEN
Guaico Culex virus (GCXV) is a newly identified segmented Jingmenvirus from Culex spp. mosquitoes in Central and South America. The genome of GCXV is composed of four or five single-stranded positive RNA segments. However, the infection kinetics and transmission capability of GCXV in mosquitoes remain unknown. In this study, we used reverse genetics to rescue two GCXVs (4S and 5S) that contained four and five RNA segments, respectively, in C6/36 âcells. Further in vitro characterization revealed that the two GCXVs exhibited comparable replication kinetics, protein expression and viral titers. Importantly, GCXV RNAs were detected in the bodies, salivary glands, midguts and ovaries of Culex quinquefasciatus at 4-10 days after oral infection. In addition, two GCXVs can colonize Cx. quinquefasciatus eggs, resulting in positive rates of 15%-35% for the second gonotrophic cycle. In conclusion, our results demonstrated that GCXVs with four or five RNA segments can be detected in Cx. quinquefasciatus eggs during the first and second gonotrophic cycles after oral infection.
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Culex , Mosquitos Vectores , ARN Viral , Replicación Viral , Animales , Culex/virología , Mosquitos Vectores/virología , ARN Viral/genética , Femenino , Línea Celular , Flavivirus/genética , Flavivirus/fisiología , Flavivirus/aislamiento & purificación , Cinética , Carga Viral , Genoma Viral , Glándulas Salivales/virologíaRESUMEN
Global-minimum optimizations combined with relativistic quantum chemistry calculations have been performed to characterize the ground-state stable structures of four titled compounds and to analyze the bonding properties. Th2C8 was identified as being a ThC4-Th(C2)2 structure, U2C8 has been found to favor the U-U(C8) structure, and both Th3C8 and U3C8 adopt the (AnC3)2-(AnC2) structure. Then, the wave function analyses reveal that the interactions between the Th 7s-based orbital and the σg molecular orbital of the C2 unit compensate for the excitation energy of 7s16d1 â 6d2 and lead to the stabilization of two Th(IV)s in the ThC4-Th(C2)2 structure. It also reveals that the U species exhibit magnetic exchange coupling behavior in UxC8, for instance, as seen in the direct interaction of U2C8 and the superexchange pathway of U3C8, which effectively stabilizes their low-spin states. This interpretation indicates that the geometric and electronic structures of AnxC8 species are largely influenced by the local magnetic moment and spin correlation.
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A pair of new chromone derivative enantiomers, (+)-xylarichromone A (1a) and (-)-xylarichromone A (1b), were isolated from the solid fermentation of Xylaria nigripes. The planar structure of 1 was determined by extensive NMR spectroscopic data, and its absolute configuration was assigned by comparison the ECD spectra with the known chromone derivatives. Compound 1 was the first chromone derivative reported from this medicinal fungus. The neuroprotective effects of 1 against oxygen and glucose deprivation (OGD) induced pheochromocytoma-12 cells (PC12) injury was investigated.
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Ascomicetos , Cromonas , Cromonas/farmacología , Cromonas/química , Estructura Molecular , Espectroscopía de Resonancia MagnéticaRESUMEN
OBJECTIVE: To quantify the results of superficial parotidectomy (SP) and partial SP (PSP) for benign parotid tumours using a systematic evaluation method. METHODS: A systematic search of English and Chinese databases (PubMed, Web of Science, Cochrane Library, China Knowledge Network, Wanfang and Vipshop) was conducted to include studies comparing the treatment outcomes of SP with PSP. RESULTS: Twenty-three qualified, high-quality studies involving 2844 patients were included in this study. The results of this study showed that compared to the SP surgical approach, the PSP surgical approach reduced the occurrence of temporary facial palsy (OR = 0.33; 95% confidence interval [CI] 0.26-0.41), permanent facial palsy (OR = 0.28; 95% CI 0.16-0.52) and Frey syndrome (OR = 0.36; 95% CI 0.23-0.56) in patients after surgery, and the surgery operative time was reduced by approximately 27.35 min (95% CI - 39.66, - 15.04). However, the effects of PSP versus SP on salivary fistula (OR = 0.70; 95% CI 0.40-1.24), sialocele (OR = 1.48; 95% CI 0.78-2.83), haematoma (OR = 0.34; 95% CI 0.11-1.01) and tumour recurrence rate (OR = 1.41; 95% CI 0.48-4.20) were not statistically significant. CONCLUSION: Compared with SP, PSP has a lower postoperative complication rate and significantly shorter operative time, suggesting that it could be used as an alternative to SP in the treatment of benign parotid tumours with the right indications.