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INTRODUCTION: Excess salt intake is not only an independent risk factor for heart failure, but also one of the most important dietary factors associated with cardiovascular disease worldwide. Metabolic reprogramming in cardiomyocytes is an early event provoking cardiac hypertrophy that leads to subsequent cardiovascular events upon high salt loading. Although SGLT2 inhibitors, such as canagliflozin, displayed impressive cardiovascular health benefits, whether SGLT2 inhibitors protect against cardiac hypertrophy-related metabolic reprogramming upon salt loading remain elusive. OBJECTIVES: To investigate whether canagliflozin can improve salt-induced cardiac hypertrophy and the underlying mechanisms. METHODS: Dahl salt-sensitive rats developed cardiac hypertrophy by feeding them an 8% high-salt diet, and some rats were treated with canagliflozin. Cardiac function and structure as well as mitochondrial function were examined. Cardiac proteomics, targeted metabolomics and SIRT3 cardiac-specific knockout mice were used to uncover the underlying mechanisms. RESULTS: In Dahl salt-sensitive rats, canagliflozin showed a potent therapeutic effect on salt-induced cardiac hypertrophy, accompanied by lowered glucose uptake, reduced accumulation of glycolytic end-products and improved cardiac mitochondrial function, which was associated with the recovery of cardiac expression of SIRT3, a key mitochondrial metabolic regulator. Cardiac-specific knockout of SIRT3 not only exacerbated salt-induced cardiac hypertrophy but also abolished the therapeutic effect of canagliflozin. Mechanistically, high salt intake repressed cardiac SIRT3 expression through a calcium-dependent epigenetic modifications, which could be blocked by canagliflozin by inhibiting SGLT1-mediated calcium uptake. SIRT3 improved myocardial metabolic reprogramming by deacetylating MPC1 in cardiomyocytes exposed to pro-hypertrophic stimuli. Similar to canagliflozin, the SIRT3 activator honokiol also exerted therapeutic effects on cardiac hypertrophy. CONCLUSION: Cardiac mitochondrial dysfunction caused by SIRT3 repression is a critical promotional determinant of metabolic pattern switching underlying salt-induced cardiac hypertrophy. Improving SIRT3-mediated mitochondrial function by SGLT2 inhibitors-mediated calcium handling would represent a therapeutic strategy against salt-related cardiovascular events.
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BACKGROUND: The renal proximal tubule (RPT) plays a pivotal role in regulating sodium reabsorption and thus blood pressure (BP). Transient receptor potential ankyrin 1 (TRPA1) has been reported to protect against renal injury by modulating mitochondrial function. We hypothesize that the activation of TRPA1 by its agonist cinnamaldehyde may mitigate high-salt intake-induced hypertension by inhibiting urinary sodium reabsorption through restoration of renal tubular epithelial mitochondrial function. METHODS: Trpa1-deficient (Trpa1-/-) mice and wild-type (WT) mice were fed standard laboratory chow [normal diet (ND) group, 0.4% salt], standard laboratory chow with 8% salt [high-salt diet (HS) group], or standard laboratory chow with 8% salt plus 0.015% cinnamaldehyde [high-salt plus cinnamaldehyde diet (HSC) group] for 6 months. Urinary sodium excretion, reactive oxygen species (ROS) production, mitochondrial function, and the expression of sodium hydrogen exchanger isoform 3 (NHE3) and Na+/K+-ATPase of RPTs were determined. RESULTS: Chronic dietary cinnamaldehyde supplementation reduced tail systolic BP and 24-hour ambulatory arterial pressure in HS-fed WT mice. Compared with the mice fed HS, cinnamaldehyde supplementation significantly increased urinary sodium excretion, inhibited excess ROS production, and alleviated mitochondrial dysfunction of RPTs in WT mice. However, these effects of cinnamaldehyde were absent in Trpa1-/- mice. Furthermore, chronic dietary cinnamaldehyde supplementation blunted HS-induced upregulation of NHE3 and Na+/K+-ATPase in WT mice but not Trpa1-/- mice. CONCLUSIONS: The present study demonstrated that chronic activation of Trpa1 attenuates HS-induced hypertension by inhibiting urinary sodium reabsorption through restoring renal tubular epithelial mitochondrial function. Renal TRPA1 may be a potential target for the management of excessive dietary salt intake-associated hypertension.
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Acroleína , Hipertensão , Camundongos Knockout , Mitocôndrias , Cloreto de Sódio na Dieta , Canal de Cátion TRPA1 , Animais , Canal de Cátion TRPA1/metabolismo , Canal de Cátion TRPA1/genética , Acroleína/análogos & derivados , Acroleína/farmacologia , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , ATPase Trocadora de Sódio-Potássio/metabolismo , Modelos Animais de Doenças , Espécies Reativas de Oxigênio/metabolismo , Trocador 3 de Sódio-Hidrogênio/metabolismo , Trocador 3 de Sódio-Hidrogênio/genética , Túbulos Renais Proximais/metabolismo , Túbulos Renais Proximais/efeitos dos fármacos , Camundongos , Pressão Sanguínea/efeitos dos fármacosRESUMO
BACKGROUND: Roux-en-Y gastric bypass (RYGB) surgery is an effective metabolic surgery against diabetes and obesity. Clinical evidence indicates that patients with severe obesity have a poor curative effect in losing weight if they suffer from leptin or its receptor deficiency, but the underlying mechanism remains elusive. Here, we investigated the effect of leptin receptor deficiency on metabolic dysfunction in db/db mice treated by RYGB surgery. METHODS: The db/db mice and their heterozygote control db/m mice were subjected to RYGB or sham surgery. Body weight, blood glucose, food intake and glucose tolerance were evaluated. Micro-PET/CT and histological analysis were performed to examine the glucose uptake of tissues and the fat changes in mice. The key factors in glucose and fatty acid metabolism were detected by western blot analysis. RESULTS: Compared with the sham group, the db/db mice in the RYGB group showed more significant weight regain after surgical recovery and improvement in hyperinsulinemia and glucose tolerance. However, the total body fat and multiple organ lipid deposition of RYGB-treated db/db mice was increased. The underlying mechanism studies suggested that the activation of AMPK regulated GLUT4 to increase glucose uptake, but AMPK could not promote fatty acid oxidation through the JAK2/STAT3 pathway under leptin receptor deficiency in db/db mice. CONCLUSION: We conclude that leptin receptor deficiency impedes the AMPK activation-mediated fat catabolism but does not affect AMPK-related glucose utilization after metabolic surgery in db/db mice. This result helps select surgical indications for patients with obesity and diabetes.
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OBJECTIVE: Metabolic reprogramming is a main feature of proinflammatory macrophage polarization, a process that leads to inflammation in dysfunctional adipose tissue. Therefore, the study aim was to explore whether sirtuin 3 (SIRT3), a mitochondrial deacetylase, participates in this pathophysiological process. METHODS: Macrophage-specific Sirt3 knockout (Sirt3-MKO) mice and wild-type littermates were treated with a high-fat diet. Body weight, glucose tolerance, and inflammation were evaluated. Bone marrow-derived macrophages and RAW264.7 cells were treated with palmitic acid to explore the mechanism of SIRT3 on inflammation. RESULTS: The expression of SIRT3 was significantly repressed in both bone marrow-derived macrophages and adipose tissue macrophages in mice fed with a high-fat diet. Sirt3-MKO mice exhibited accelerated body weight and severe inflammation, accompanied with reduced energy expenditure and worsened glucose metabolism. In vitro experiments showed that SIRT3 inhibition or knockdown exacerbated palmitic acid-induced proinflammatory macrophage polarization, whereas SIRT3 restoration displayed opposite effects. Mechanistically, SIRT3 deficiency resulted in hyperacetylation of succinate dehydrogenase that led to succinate accumulation, which suppressed the transcription of Kruppel-like factor 4 via increasing histone methylation on its promoter, thus evoking proinflammatory macrophages. CONCLUSIONS: This study emphasizes an important preventive role of SIRT3 in macrophage polarization and implies that SIRT3 is a promising therapeutic target for obesity.
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Resistência à Insulina , Sirtuína 3 , Camundongos , Animais , Sirtuína 3/genética , Sirtuína 3/metabolismo , Sirtuína 3/farmacologia , Ácido Palmítico/farmacologia , Obesidade/metabolismo , Inflamação/metabolismo , Dieta Hiperlipídica/efeitos adversos , Peso Corporal , Camundongos Knockout , Macrófagos/metabolismo , Mitocôndrias/metabolismo , Camundongos Endogâmicos C57BLRESUMO
Metabolic reprogramming of macrophages initiates the polarization of pro-inflammatory macrophages that exacerbates adipocyte dysfunction and obesity. The imbalance of mitochondrial Ca2+ homeostasis impairs mitochondrial function and promotes inflammation. Connexin 43 (Cx43), a ubiquitous gap junction protein, has been demonstrated to regulate intracellular Ca2+ homeostasis. Here we explored whether macrophage Cx43 affects the obesity process by regulating the polarization of macrophage. HFD treatment induced obesity and exacerbated macrophages infiltration with upregulation of macrophages Cx43. Macrophage-specific knockout of Cx43 reduced HFD-induced obesity by alleviating inflammation in adipose tissue, with less pro-inflammatory M1 macrophage infiltration. Consistently, inhibition or knockdown of Cx43 improved palmitic acid (PA) induced mitochondrial dysfunction, as indicated by improved oxidative phosphorylation (OXPHOS), reduced formation of mitochondria-associated membranes (MAM) and mitochondrial Ca2+ overload. Mechanistically, Cx43 interacted with the mitochondrial Ca2+ uniporter (MCU) and knockdown of Cx43 alleviated PA-induced succinate dehydrogenase (SDH) oxidation by lowering MCU-mediated mitochondrial Ca2+ uptake, which then, promoting the polarization of pro-inflammatory M1 macrophages. Thus, this study identified Cx43 as a mitochondrial Ca2+ regulator that aggravates obesity via promoting macrophages polarized to M1 pro-inflammatory phenotype and suggests that Cx43 might be a promising therapeutic target antagonizing obesity.
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Cálcio , Conexina 43 , Humanos , Cálcio/metabolismo , Conexina 43/metabolismo , Tecido Adiposo/metabolismo , Macrófagos/metabolismo , Obesidade/metabolismo , Inflamação/metabolismo , Mitocôndrias/metabolismoRESUMO
Background Salt-sensitive hypertension is highly prevalent and associated with cardiorenal damage. Large clinical trials have demonstrated that SGLT2 (sodium-glucose cotransporter 2) inhibitors exert hypotensive effect and cardiorenal protective benefits in patients with hypertension with and without diabetes. However, the underlying mechanism remains elusive. Methods and Results Dahl salt-sensitive rats and salt-insensitive controls were fed with 8% high-salt diet and some of them were treated with canagliflozin. The blood pressure, urinary sodium excretion, and vascular function were detected. Transient receptor potential channel 3 (TRPC3) knockout mice were used to explain the mechanism. Canagliflozin treatment significantly reduced high-salt-induced hypertension and this effect was not totally dependent on urinary sodium excretion in salt-sensitive hypertensive rats. Assay of vascular function and proteomics showed that canagliflozin significantly inhibited vascular cytoplasmic calcium increase and vasoconstriction in response to high-salt diet. High salt intake increased vascular expression of TRPC3 in salt-sensitive rats, which could be alleviated by canagliflozin treatment. Overexpression of TRPC3 mimicked salt-induced vascular cytosolic calcium increase in vitro and knockout of TRPC3 erased the antihypertensive effect of canagliflozin. Mechanistically, high-salt-induced activation of NCX1 (sodium-calcium exchanger 1) reverse mode increased cytoplasmic calcium level and vasoconstriction, which required TRPC3, and this process could be blocked by canagliflozin. Conclusions We define a previously unrecognized role of TRPC3/NCX1 mediated vascular calcium dysfunction in the development of high-salt-induced hypertension, which can be improved by canagliflozin treatment. This pathway is potentially a novel therapeutic target to antagonize salt-sensitive hypertension.
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Canagliflozina , Hipertensão , Inibidores do Transportador 2 de Sódio-Glicose , Animais , Pressão Sanguínea , Cálcio/metabolismo , Canagliflozina/farmacologia , Canagliflozina/uso terapêutico , Glucose/farmacologia , Hipertensão/induzido quimicamente , Hipertensão/tratamento farmacológico , Hipertensão/metabolismo , Camundongos , Ratos , Ratos Endogâmicos Dahl , Sódio/metabolismo , Cloreto de Sódio na Dieta/metabolismo , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Canais de Cátion TRPC/genéticaRESUMO
Transient receptor potential channel 5 (TRPC5) is predominantly distributed in the brain, especially in the central amygdala (CeA), which is closely associated with pain and addiction. Although mounting evidence indicates that the CeA is related to energy homeostasis, the possible regulatory effect of TRPC5 in the CeA on metabolism remains unclear. Here, we reported that the expression of TRPC5 in the CeA of mice was increased under a high-fat diet (HFD). Specifically, the deleted TRPC5 protein in the CeA of mice using adeno-associated virus resisted HFD-induced weight gain, accompanied by increased food intake. Furthermore, the energy expenditure of CeA-specific TRPC5 deletion mice (TRPC5 KO) was elevated due to augmented white adipose tissue (WAT) browning and brown adipose tissue (BAT) activity. Mechanistically, deficiency of TRPC5 in the CeA boosted nonshivering thermogenesis under cold stimulation by stimulating sympathetic nerves, as the ß3-adrenoceptor (Adrb3) antagonist SR59230A blocked the effect of TRPC5 KO on this process. In summary, TRPC5 deletion in the CeA alleviated the metabolic deterioration of mice fed a HFD, and these phenotypic improvements were correlated with the increased sympathetic distribution and activity of adipose tissue.
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Núcleo Central da Amígdala , Dieta Hiperlipídica , Obesidade , Canais de Cátion TRPC , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Núcleo Central da Amígdala/metabolismo , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/genética , Obesidade/metabolismo , Canais de Cátion TRPC/genética , Canais de Cátion TRPC/metabolismo , TermogêneseRESUMO
BACKGROUND: Altered adipokine secretion in dysfunctional adipose tissue facilitates the development of atherosclerotic diseases including lower extremity peripheral artery disease (PAD). Asprosin is a recently identified adipokine and displays potent regulatory role in metabolism, but the relationship between asprosin and lower extremity PAD remains uninvestigated. METHODS: 33 type 2 diabetes mellitus (T2DM) patients (DM), 51 T2DM patients with PAD (DM + PAD) and 30 healthy normal control (NC) volunteers were recruited and the blood samples were collected for detecting the circulatory asprosin level and metabolomic screening. RNA sequencing was performed using the aorta tissues from the type 2 diabetic db/db mice and human umbilical vein endothelial cells (HUVECs) were treated with asprosin to determine its impact on the endothelial-to-mesenchymal transition (EndMT). RESULTS: The circulating levels of asprosin in DM + PAD group were significantly higher than that of NC group and the DM group. Circulating asprosin level was remarkably negatively correlated with ankle-brachial index (ABI), even after adjusting for age, sex, body mass index (BMI) and other traditional risk factors of PAD. Logistic regression analysis revealed that asprosin is an independent risk factor for PAD and receiver-operator characteristic (ROC) curve determined a good sensitivity (74.5%) and specificity (74.6%) of asprosin to distinguish PAD. Data from metabolomics displayed a typical characteristics of de novo amino acid synthesis in collagen protein production by myofibroblasts in patients with PAD and activation of TGF-ß signaling pathway appeared in the aortic tissue of db/db mice. Asprosin directly induces EndMT in HUVECs in a TGF-ß-dependent manner as TGF-ß signaling pathway inhibitor SB431542 erased the promotional effect of asprosin on EndMT. CONCLUSIONS: Elevated circulatory asprosin level is an independent risk factor of lower extremity PAD and might serve as a diagnostic marker. Mechanistically, asprosin directly induces EndMT that participates in vascular injury via activation of TGF-ß signaling pathway. Trial registration This trial was registered at clinicaltrials.gov as NCT05068895.
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Diabetes Mellitus Tipo 2 , Doença Arterial Periférica , Animais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Endotélio Vascular , Células Endoteliais da Veia Umbilical Humana , Humanos , Extremidade Inferior , Camundongos , Doença Arterial Periférica/diagnósticoRESUMO
The combination of obesity and hypertension is associated with high morbidity and mortality; however, the mechanism underlying obesity-induced hypertension remains unclear. In this study, we detected the possible effects of TRPV1, a previously identified antihypertensive calcium (Ca2+) channel in adipose tissue, on the occurrence of obesity and hypertension in mice lacking UCP1, a spontaneously genetically manipulated obesity model, by generating TRPV1 and UCP1 double knockout mice. In these mice, obesity and hypertension appeared earlier and were more severe than in mice with the knockout of UCP1 or TRPV1 alone. The knockout of TRPV1 in UCP1 knockout mice further reduced functional brown adipose tissue (BAT) generation; decreased resting oxygen consumption, heat production, and locomotor activities; and was accompanied by severe mitochondrial respiratory dysfunction in BAT. Mechanistically, TRPV1, UCP1, and LETM1 acted as a complex to maintain an appropriate mitochondrial Ca2+ level, and TRPV1 knockout caused a compensatory increase in mitochondrial Ca2+ uptake via LETM1 activation. However, the compensatory response was blocked in UCP1-/- mice, resulting in dramatically reduced mitochondrial Ca2+ uptake and higher production of ATP and oxidative stress. This study provides in vivo evidence for the critical role of BAT mitochondrial Ca2+ homeostasis in obesity-associated hypertension and indicates that the TRPV1/UCP1/LETM1 complex may be an alternative intervention target.
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Tecido Adiposo Marrom , Hipertensão , Tecido Adiposo Marrom/metabolismo , Animais , Cálcio/metabolismo , Homeostase , Hipertensão/etiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/complicações , Canais de Cátion TRPV/genéticaRESUMO
A facile method, cool microcontact printing (cool µCP), of fabricating microgel patterns under ambient conditions is developed. By using spontaneously condensed water on the surface of cold items and the phase transition of polymer microgels below the lower critical solution temperature (LCST), a cool poly(dimethylsiloxane) (PDMS) stamp can be easily decorated with a thin layer of water ink and its pattern can substantially transfer to a substrate that is assembled with microgels. As a proof of concept, one kind of thermosensitive microgel (i.e., poly(N-isopropylacrylamide) (pNIPAM)) is selected to demonstrate our method. A series of pNIPAM microgel patterns with various geometries can be easily generated by featured PDMS stamps through a cool µCP method. The results of control experiment using room-temperature PDMS stamps or patterning the pNIPAM microgel-incorporated fluorescent probe reveal that condensed cold water on a cool PDMS stamp plays an important role when microgel particles are lifted off. In addition, it is also observed that both humidity and contact pressure have effects on the shapes of the pattern fabricated by cool µCP, and more precise or sophisticate patterns can be obtained by adjusting the conditions. It is envisioned that this practically available method, as a good extension to µCP, can facilitate the design of complex patterns, affording great convenience for many inherent applications ranging from photonics to chemical sensing to biotechnology.
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Polímeros/química , Impressão , Resinas Acrílicas/química , Dimetilpolisiloxanos/química , Nylons/química , Fotoquímica/métodosRESUMO
OBJECTIVE: Obesity is a prominent component of metabolic syndrome and a major risk factor for renal disease. The aim of this study was to explore the effect of cross-talk between peroxisome proliferator-activated receptor (PPAR)δ and p38 mitogen-activated protein kinase (p38 MAPK) on obesity-related glomerulopathy. DESIGN AND METHODS: Male Wistar rats were randomly assigned to standard laboratory chow or a high-fat diet for 32 weeks. Glomerular mesangial cells HBZY-1 and mature differentiation 3T3-L1 cells were cocultured and were transfected with PPARδ-expressing vectors or treated with agonist or inhibitor of PPARδ or p38 MAPK. RESULTS: Rats on a high-fat diet showed typical characteristics of metabolic syndrome including obesity, dyslipidemia, insulin resistance, and hypertension. Rats on a high-fat diet also had significant glomerular hypertrophy and extracellular matrix accumulation, which were accompanied by increased p38 MAPK phosphorylation and decreased PPARδ expression in the kidney tissue. The roles of p38 MAPK and PPARδ in a coculture system of mesangial cells and mature differentiation 3T3-L1 cells were further explored. PPARδ suppression promoted laminin and type IV collagen secretion through p38 MAPK phosphorylation in mesangial cells, whereas PPARδ overexpression or PPARδ agonist attenuated phosphorylation of p38 MAPK and laminin and type IV collagen secretion. CONCLUSIONS: The characteristics of obesity-related glomerulopathy, which might be partly caused by PPARδ suppression-induced p38 MAPK activation and laminin and type IV collagen secretion was demonstrated.
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Nefropatias/patologia , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Obesidade/fisiopatologia , PPAR delta/metabolismo , Células 3T3-L1 , Animais , Western Blotting , Diferenciação Celular , Colágeno/antagonistas & inibidores , Colágeno/metabolismo , Dieta Hiperlipídica , Mesângio Glomerular/citologia , Mesângio Glomerular/patologia , Imuno-Histoquímica , Rim/metabolismo , Rim/patologia , Nefropatias/etiologia , Laminina/antagonistas & inibidores , Laminina/metabolismo , Sistema de Sinalização das MAP Quinases , Masculino , Células Mesangiais/metabolismo , Células Mesangiais/patologia , Síndrome Metabólica/complicações , Síndrome Metabólica/fisiopatologia , Camundongos , Proteína Quinase 14 Ativada por Mitógeno/genética , Obesidade/complicações , PPAR delta/genética , Fosforilação , Ratos , Ratos WistarRESUMO
Polymer electrets are one of the most important series of electrets, which are widely used both in academic research and industrial applications. The effect of trapped charges on dielectric properties of the polymer electret is critical for more intelligent utilization of these materials. Herein we report the charge-induced polymer relaxation reflected by the local dewetting of the polymer electrets with charge patterns. Because the difference in charge-induced relaxation results in selective dewetting of thin polymer films, polymers in the charged areas are preferentially dewetted from the substrate compared with the neutral areas under heating or solvent annealing, leading to the appearance of hole arrays. Therefore, the effect of trapped charges on relaxation was also studied via monitoring the relaxation behaviours of homo-polymer and block copolymer films as well as measuring the mechanical properties of homo-polymers with charge patterns. These results demonstrate that the charge trapped in polymer electrets could accelerate relaxation and drive the dewetting process of thin polymer films.
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There is great interest in utilization of silicon-containing nanostructures as anode materials for lithium-ion batteries but usually limited by manufacturing cost, their intrinsic low electric conductivity, and large volume changes during cycling. Here we present a facile process to fabricate graphene-wrapped silicon nanowires (GNS@Si NWs) directed by electrostatic self-assembly. The highly conductive and mechanical flexible graphene could partially accommodate the large volume change associated with the conversion reaction and also contributed to the enhanced electronic conductivity. The as-prepared GNS@Si NWs delivered a reversible capacity of 1648 mAh·g(-1) with an initial Coulombic efficiency as high as 80%. Moreover, capacity remained 1335 mAh·g(-1) after 80 cycles at a current of 200 mA·g(-1), showing significantly improved electrochemical performance in terms of rate capability and cycling performance.
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The recent discovery of superconductivity with a transition temperature (T(c)) at 18â K in K(x)picene has extended the possibility of high-T(c) superconductors in organic materials. Previous experience based on similar hydrocarbons, like alkali-metal doped phenanthrene, suggested that even higher transition temperatures might be achieved in alkali-metals or alkali-earth-metals doped such polycyclic-aromatic-hydrocarbons (PAHs), a large family of molecules composed of fused benzene rings. Here we report the discovery of high-T(c) superconductivity at 33â K in K-doped 1,2:8,9-dibenzopentacene (C(30)H(18)). To our best knowledge, it is higher than any T(c) reported previously for an organic superconductor under ambient pressure. This finding provides an indication that superconductivity at much higher temperature may be possible in such PAHs system and is worthy of further exploration.
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Here we report the successful synthesis of superconducting potassium-doped few-layer graphene (K-doped FLG) with a transition temperature of 4.5 K, which is 1 order of magnitude higher than that observed in the bulk potassium graphite intercalation compound (GIC) KC(8) (T(c) = 0.39 K). The realization of superconductivity in K-doped FLG shows the potential for the development of new superconducting electronic devices using two-dimensional (2D) graphene as a basis material.
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The exploration of new methods and techniques for application in diverse fields, such as photonics, microfluidics, biotechnology and flexible electronics is of increasing scientific and technical interest for multiple uses over distance of 10-100 nm. This article discusses edge transfer printing--a series of unconventional methods derived from soft lithography for nanofabrication. It possesses the advantages of easy fabrication, low-cost and great serviceability. In this paper, we show how to produce exposed edges and use various materials for edge transfer printing, while nanoskiving, nanotransfer edge printing and tunable cracking for nanogaps are introduced. Besides this, different functional materials, such as metals, inorganic semiconductors and polymers, as well as localised heating and charge patterning, are described here as unconventional "inks" for printing. Edge transfer printing, which can effectively produce sub-100 nm scale ultra-fine structures, has broad applications, including metallic nanowires as nanoelectrodes, semiconductor nanowires for chemical sensors, heterostructures of organic semiconductors, plasmonic devices and so forth.
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Cristalização/métodos , Impressão Molecular/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Substâncias Macromoleculares/química , Conformação Molecular , Tamanho da Partícula , Propriedades de SuperfícieRESUMO
Impaired aerobic exercise capacity and skeletal muscle dysfunction are associated with cardiometabolic diseases. Acute administration of capsaicin enhances exercise endurance in rodents, but the long-term effect of dietary capsaicin is unknown. The capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1) cation channel has been detected in skeletal muscle, the role of which remains unclear. Here we report the function of TRPV1 in cultured C2C12 myocytes and the effect of TRPV1 activation by dietary capsaicin on energy metabolism and exercise endurance of skeletal muscles in mice. In vitro, capsaicin increased cytosolic free calcium and peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression in C2C12 myotubes through activating TRPV1. In vivo, PGC-1α in skeletal muscle was upregulated by capsaicin-induced TRPV1 activation or genetic overexpression of TRPV1 in mice. TRPV1 activation increased the expression of genes involved in fatty acid oxidation and mitochondrial respiration, promoted mitochondrial biogenesis, increased oxidative fibers, enhanced exercise endurance and prevented high-fat diet-induced metabolic disorders. Importantly, these effects of capsaicin were absent in TRPV1-deficient mice. We conclude that TRPV1 activation by dietary capsaicin improves energy metabolism and exercise endurance by upregulating PGC-1α in skeletal muscles. The present results indicate a novel therapeutic strategy for managing metabolic diseases and improving exercise endurance.
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Metabolismo Energético , Condicionamento Físico Animal/fisiologia , Resistência Física/fisiologia , Canais de Cátion TRPV/metabolismo , Transativadores/metabolismo , Regulação para Cima , Animais , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Canais de Cátion TRPV/deficiência , Canais de Cátion TRPV/genética , Fatores de TranscriçãoRESUMO
Vascular endothelial dysfunction has been demonstrated in metabolic syndrome (MS). Chronic administration of rosiglitazone ameliorates endothelial dysfunction through PPARγ-mediated metabolic improvements. Recently, studies suggested that single dose of rosiglitazone also has direct vascular effects, but the mechanisms remain uncertain. Here we established a diet-induced rat model of MS. The impaired vasorelaxation in MS rats was improved by incubating arteries with rosiglitazone for one hour. Importantly, this effect was blocked by either inhibition of PPARγ or PPARδ. In cultured endothelial cells, acute treatment with rosiglitazone increased the phosphorylation of Akt and eNOS and the production of NO. These effects were also abolished by inhibition of PPARγ, PPARδ, or PI3K. In conclusion, rosiglitazone improved endothelial function through both PPARγ- and PPARδ-mediated phosphorylation of Akt and eNOS, which might help to reconsider the complex effects and clinical applications of rosiglitazone.
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You crack me up: A topographically patterned PDMS stamp was coated with thin metal film and swelled under organic vapor to induce the tunable cracking of the brittle film into metallic nanostructures (see SEM images, scale bars 1â µm). UV/Vis spectra, OLED efficiency, and SERS spectra demonstrate the fine controllability of the metallic nanostructures, the well-ordered and highly regulable surface plasmons, and the facile fabrication process.