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1.
Sci Rep ; 13(1): 12657, 2023 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-37542076

RESUMO

The neutron capture cross section of [Formula: see text]Ta is relevant to s-process of nuclear astrophysics, extraterrestrial samples analysis in planetary geology and new generation nuclear energy system design. The [Formula: see text]Ta([Formula: see text]) cross section had been measured between 1 eV and 800 keV at the back-streaming white neutron facility (Back-n) of China spallation neutron source(CSNS) using the time-of-flight (TOF) technique and [Formula: see text] liquid scintillator detectors. The experimental results are compared with the data of several evaluated libraries and previous experiments in the resolved and unresolved resonance region. Resonance parameters are extracted using the R-Matrix code SAMMY in the 1-700 eV region. The astrophysical Maxwell average cross section(MACS) from kT = 5 to 100 keV is calculated over a sufficiently wide range of neutron energies. For the characteristic thermal energy of an astrophysical site, at kT = 30keV the MACS value of [Formula: see text]Ta is 834 ± 75 mb, which shows an obvious discrepancy with the Karlsruhe Astrophysical Database of Nucleosynthesis in Stars (KADoNiS) recommended value 766 ± 15 mb. The new measurements strongly constrain the MACS of [Formula: see text]Ta([Formula: see text]) reaction in the stellar s-process temperatures.

2.
Zhen Ci Yan Jiu ; 48(4): 347-52, 2023 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-37186198

RESUMO

OBJECTIVE: To observe the effect of moxibustion on the expressions of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in ankle synovial tissue of rats with adjuvant arthritis(AA), so as to explore the mechanism of moxibustion in inhibiting synovial angiogenesis and improving joint symptoms of rheumatoid arthritis. METHODS: Sixty healthy male SD rats were randomly divided into normal group, model group, moxibustion group and medication group, with 15 rats in each group. AA rat model was established by subcutaneous injection of Freund's complete adjuvant into the right hind paw. Rats in the moxibustion group were treated with "Zusanli" (ST36), "Guanyuan" (CV4) and "Ashi" point moxibustion, 20 min each time, once a day, for consecutive 3 weeks. Rats in the medication group were given methotrexate (0.35 mg/kg) intragastric administration, twice a week, for consecutive 3 weeks. Foot plantar volume of rats was measured by toe volume mea-suring instrument. HE staining was used to observe the histopathology of ankle synovium. The protein expressions of HIF-1α and VEGF in ankle synovial tissue were detected by immunohistochemistry and Western blot. RESULTS: Compared with the normal group, the foot plantar volume and the protein expressions of HIF-1α and VEGF in synovial tissue of ankle joint were significantly increased (P<0.01) in the model group, the synovial tissue showed obvious hyperplasia and a large number of neovasculogenesis. Following the interventions, the foot plantar volume and the protein expressions of HIF-1α and VEGF in synovial tissue of ankle joint were significantly decreased (P<0.05, P<0.01) in both moxibustion and medication groups in contrast to the model group, and there was no obvious proliferation of synovial tissue, and only a few neovascularization was observed. Compared with the medication group, the foot plantar volume was decreased (P<0.05) in the moxibustion group. CONCLUSION: Moxibustion can improve joint swelling and inhibit synovial angiogenesis in AA rats, and its mechanism may be related to down-regulating of HIF-1α and VEGF protein expressions.


Assuntos
Artrite Experimental , Moxibustão , Animais , Masculino , Ratos , Tornozelo , Articulação do Tornozelo/metabolismo , Artrite Experimental/genética , Artrite Experimental/terapia , Hipóxia/metabolismo , Ratos Sprague-Dawley , Membrana Sinovial/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética
3.
Proc Natl Acad Sci U S A ; 118(37)2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34493662

RESUMO

Mitochondria form a complex, interconnected reticulum that is maintained through coordination among biogenesis, dynamic fission, and fusion and mitophagy, which are initiated in response to various cues to maintain energetic homeostasis. These cellular events, which make up mitochondrial quality control, act with remarkable spatial precision, but what governs such spatial specificity is poorly understood. Herein, we demonstrate that specific isoforms of the cellular bioenergetic sensor, 5' AMP-activated protein kinase (AMPKα1/α2/ß2/γ1), are localized on the outer mitochondrial membrane, referred to as mitoAMPK, in various tissues in mice and humans. Activation of mitoAMPK varies across the reticulum in response to energetic stress, and inhibition of mitoAMPK activity attenuates exercise-induced mitophagy in skeletal muscle in vivo. Discovery of a mitochondrial pool of AMPK and its local importance for mitochondrial quality control underscores the complexity of sensing cellular energetics in vivo that has implications for targeting mitochondrial energetics for disease treatment.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Metabolismo Energético , Mitocôndrias/patologia , Mitofagia , Condicionamento Físico Animal , Proteínas Quinases Ativadas por AMP/genética , Animais , Humanos , Masculino , Camundongos , Mitocôndrias/metabolismo
4.
Diabetes Metab Syndr Obes ; 13: 4209-4219, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33192083

RESUMO

OBJECTIVE: Ketogenic diet (KD) and high-intensity interval training (HIIT) have preclinical benefits for type 2 diabetes (Db). However, the health risks of long-term KD use in diabetes should be ascertained and prevented. We hypothesized that KD-induced liver fibrosis in type 2 diabetic mice could be ameliorated by HIIT. METHODS: Streptozotocin-induced type 2 diabetic mice were divided into high-fat diet (HFD) control (Db+HFD+Sed), KD control (Db+KD+Sed), HFD coupled with HIIT (Db+HFD+HIIT), and KD coupled with HIIT (Db+KD+HIIT) groups (n=6, per group). Control mice were kept in sedentary (Sed), while HIIT group mice underwent 40-minute high-intensity interval training three alternate days per week. After 8-week intervention, the indicators of body weight and insulin resistance, oxidative stress markers, hepatic fibrosis, genetic and protein expression of related pathways were tested. RESULTS: We found that fasting blood glucose level was reduced in the Db+HFD+HIIT, Db+KD+Sed, and Db+KD+HIIT groups. Insulin sensitivity was increased in diabetic mice of these groups, whereas ROS levels were decreased in mice that underwent HIIT. The immunohistochemical staining of liver, serum index, and hepatic parameters of diabetic mice in the KD group revealed liver fibrosis, which was significantly attenuated by HIIT. Besides, these effects of HIIT were the outcome of hepatic stellate cell's inactivation, reduced protein expression of matrix metalloproteinases and tissue inhibitor of metalloproteinases, and the inhibition of TGF-ß1/Smad signaling. CONCLUSION: KD had a profound fibrotic effect on the liver of type 2 diabetic mice, whereas HIIT ameliorated this effect. KD did not show any apparent benefit as far as glucose tolerance and homeostasis were concerned. Concisely, our results demonstrated that KD should be coupled with HIIT for the prevention and preclinical mitigation of type 2 diabetes.

5.
ACS Appl Mater Interfaces ; 11(15): 14418-14426, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30896146

RESUMO

Improving the thermal transport across interfaces is a necessary consideration for micro- and nanoelectronic devices and necessitates accurate measurement of the thermal boundary conductance (TBC) and understanding of transport mechanisms. Two-dimensional transition-metal dichalcogenides (TMDs) have been studied extensively for their electrical properties, including the metal-TMD electrical contact resistance, but the thermal properties of these interfaces are significantly less explored irrespective of their high importance in their electronic devices. We isolate individual islands of MoSe2 grown by chemical vapor deposition using photolithography and correlate the 2D variation of TBC with optical microscope images of the MoSe2 islands. We measure the 2D spatial variation of the TBC at metal-MoSe2-SiO2 interfaces using a modified time-domain thermoreflectance (TDTR) technique, which requires much less time than full TDTR scans. The thermoreflectance signal at a single probe delay time is compared with a correlation curve, which enables us to estimate the change in the signal with respect to the TBC at the metal-MoSe2-SiO2 interface as opposed to recording the decay of the thermoreflectance signal over delay times of several nanoseconds. The results show a higher TBC across the Ti-MoSe2-SiO2 interface compared to Al-MoSe2-SiO2. An image-clustering method is developed to differentiate the TBC for different numbers of MoSe2 layers, which reveals that the TBC in single-layer regions is higher than that in the bilayer. We perform traditional TDTR measurements over a range of delay times and verify that TBC is higher at the Ti-MoSe2-SiO2 interface compared to Al-MoSe2-SiO2, highlighting the importance of the choice of metal for heat dissipation at electrical contacts in TMD devices.

6.
Artigo em Inglês | MEDLINE | ID: mdl-25019834

RESUMO

Although Gibrat's law and its generalized versions have been widely used, the organizing principle behind its phenomenological theory has been poorly studied for network-structured systems. More important, its fluctuation behavior, which contradicts the prediction of the preferential attachment (PA), indicates a nontrivial mechanism that goes beyond our present knowledge based on the traditional mean-field approach. Here, we take advantage of the rich data of the Internet and aim to identify the origin of Gibrat's law by studying the empirical fluctuation behavior. We show how the correlation between the fluctuations of the node degree increment affects the dynamics of the network. Specifically, if the distribution of the correlation is symmetric, the network evolves as the classical PA, while if such symmetry breaks, the fluctuation becomes macroscopically positively correlated and contributes to the emergence of Gibrat's law. These results indicate a local collective increase in the actual network evolution, which provides a new paradigm and understanding of the related microcosmic dynamics.


Assuntos
Armazenamento e Recuperação da Informação/estatística & dados numéricos , Internet/estatística & dados numéricos , Modelos Estatísticos , Simulação por Computador , Estatística como Assunto
7.
Chemosphere ; 93(4): 590-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23800595

RESUMO

Both grate and fluidized bed incinerators are widely used for MSW incineration in China. CaO addition for removing hazardous emissions from MSWI flue gas changes the characteristics of fly ash and affects the thermal behavior of heavy metals when the ash is reheated. In the present work, two types of MSWI fly ashes, sampled from both grate and fluidized bed incinerators respectively, were thermal treated at 1023-1323 K and the fate of heavy metals was observed. The results show that both of the fly ashes were rich in Ca and Ca-compounds were the main alkaline matter which strongly affected the leaching behavior of heavy metals. Ca was mostly in the forms of Ca(OH)2 and CaCO3 in the fly ash from grate incinerator in which nascent fly ash particles were covered by Ca-compounds. In contrast, the content of Ca was lower in the fly ash from fluidized bed incinerator and Ca was mostly in the form of CaSO4. Chemical reactions among Ca-compounds caused particle agglomeration in thermal treated fly ash from grate incinerator, restraining the heavy metals volatilization. In thermal treated fly ash from fluidized bed incinerator, Ca was converted into aluminosilicates especially at 1323 K which enhanced heavy metals immobilization, decreasing their volatile fractions as well as leaching concentrations. Particle agglomeration hardly affected the leaching behavior of heavy metals. However, it suppressed the leachable-CaCrO4 formation and lowered Cr leaching concentration.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Cálcio/química , Cinza de Carvão/análise , Incineração/métodos , Metais Pesados/análise , Óxidos/química , Eliminação de Resíduos/métodos , Volatilização
9.
Macromol Rapid Commun ; 31(16): 1444-8, 2010 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-21567549

RESUMO

The bifunctional role of hydrazine as a potent nucleophile and antioxidant was investigated for the rapid aminolysis of RAFT polymers within minutes in air with effective suppression of the formation of disulfides. Using both dithioesters and trithiocarbonates as model compounds, we showed that hydrazine exhibited a significantly improved aminolysis rate when compared with a commonly used primary alkyl amine. On the basis of the exellent results with CTAs, we further studied the aminolysis of RAFT polymers prepared with either dithioesters or trithiocarbonates. In accord with the aminolysis results on CTAs, hydrazine aminolyzed RAFT polymers in an impressively short time and, more importantly, it significantly suppressed the formation of disulfides as comfirmed with GPC.

10.
Phys Rev E Stat Nonlin Soft Matter Phys ; 71(6 Pt 1): 062901, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16089796

RESUMO

The radial compression properties of single DNA molecules have been studied using vibrating scanning polarization force microscopy. By imaging DNA molecules at different vibration amplitude set-point values, we obtain the correlations between radially applied force and DNA compression, from which the radial compressive elasticity can be deduced. The estimated elastic modulus is approximately 20-70 MPa under small external forces (<0.4 nN) and increases to approximately 100-200 MPa for large loads.


Assuntos
DNA/química , DNA/ultraestrutura , Micromanipulação/métodos , Microscopia de Força Atômica/métodos , Microscopia de Polarização/métodos , Modelos Químicos , Modelos Moleculares , Força Compressiva , Simulação por Computador , DNA/análise , Elasticidade , Interpretação de Imagem Assistida por Computador/métodos , Conformação de Ácido Nucleico , Estresse Mecânico , Vibração
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