http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Germanium coating boosts lithium uptake in Si nanotube battery anodes
Haro, Marta,Song, Taeseup,Guerrero, Antonio,Bertoluzzi, Luca,Bisquert, Juan,Paik, Ungyu,Garcia-Belmonte, Germà The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.33
<P>Si nanotubes for reversible alloying reaction with lithium are able to accommodate large volume changes and offer improved cycle retention and reliable response when incorporated into battery anodes. However, Si nanotube electrodes exhibit poor rate capability because of their inherently low electron conductivity and Li ion diffusivity. Si/Ge double-layered nanotube electrodes show promise to improve structural stability and electrochemical kinetics, as compared to homogeneous Si nanotube arrays. The mechanism explaining the enhancement in the rate capabilities is revealed here by means of electrochemical impedance methods. The Ge shell efficiently provides electrons to the active materials, which increase the semiconductor conductivity thereby assisting Li<SUP>+</SUP> ion incorporation. The charge transfer resistance which accounts for the interfacial Li<SUP>+</SUP> ion intake from the electrolyte is reduced by two orders of magnitude, indicating the key role of the Ge layer as an electron supplier. Other resistive processes hindering the electrode charge–discharge process are observed to show comparable values for Si and Si/Ge array electrodes.</P> <P>Graphic Abstract</P><P>Interfacial charge transfer resistance accounting for Li intake extremely reduced by conductive germanium coating of Si nanotubes. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cp02377c'> </P>
Regulation of Hepatic Energy Metabolism and Gluconeogenesis by BAD
Gimenez-Cassina, A.,Garcia-Haro, L.,Choi, C.,Osundiji, Mayowa A.,Lane, E.A.,Huang, H.,Yildirim, Muhammed A.,Szlyk, B.,Fisher, Jill K.,Polak, K.,Patton, E.,Wiwczar, J.,Godes, M.,Lee, D.,Robertson, K.,K Cell Press 2014 Cell metabolism Vol.19 No.2
The homeostatic balance of hepatic glucose utilization, storage, and production is exquisitely controlled by hormonal signals and hepatic carbon metabolism during fed and fasted states. How the liver senses extracellular glucose to cue glucose utilization versus production is not fully understood. We show that the physiologic balance of hepatic glycolysis and gluconeogenesis is regulated by Bcl-2-associated agonist of cell death (BAD), a protein with roles in apoptosis and metabolism. BAD deficiency reprograms hepatic substrate and energy metabolism toward diminished glycolysis, excess fatty acid oxidation, and exaggerated glucose production that escapes suppression by insulin. Genetic and biochemical evidence suggests that BAD's suppression of gluconeogenesis is actuated by phosphorylation of its BCL-2 homology (BH)-3 domain and subsequent activation of glucokinase. The physiologic relevance of these findings is evident from the ability of a BAD phosphomimic variant to counteract unrestrained gluconeogenesis and improve glycemia in leptin-resistant and high-fat diet models of diabetes and insulin resistance.
An Accurate Radio Channel Model for Wireless Sensor Networks Simulation
Alejandro Martfnez-Sala,Jose-Maria Molina-Garcia-Pardo,Esteban Egea-Lopez,Javier Vales-Alonso,Leandro Juan-Llacer,Joan Garcia-Haro The Korea Institute of Information and Commucation 2005 Journal of communications and networks Vol.7 No.4
Simulations are currently an essential tool to develop and test wireless sensor networks (WSNs) protocols and to analyze future WSNs applications performance. Researchers often simulate their proposals rather than deploying high-cost test-beds or develop complex mathematical analysis. However, simulation results rely on physical layer assumptions, which are not usually accurate enough to capture the real behavior of a WSN. Such an issue can lead to mistaken or questionable results. Besides, most of the envisioned applications for WSNs consider the nodes to be at the ground level. However, there is a lack of radio propagation characterization and validation by measurements with nodes at ground level for actual sensor hardware. In this paper, we propose to use a low-computational cost, two slope, log-normal pathloss near ground outdoor channel model at 868 MHz in WSN simulations. The model is validated by extensive real hardware measurements obtained in different scenarios. In addition, accurate model parameters are provided. This model is compared with the well-known one slope path-loss model. We demonstrate that the two slope log-normal model provides more accurate WSN simulations at almost the same computational cost as the single slope one. It is also shown that the radio propagation characterization heavily depends on the adjusted model parameters for a target deployment scenario: The model parameters have a considerable impact on the average number of neighbors and on the network connectivity.
Park, Kang-Joon,Lim, Byung-Beom,Choi, Moon-Ho,Jung, Hun-Gi,Sun, Yang-Kook,Haro, Marta,Vicente, Nuria,Bisquert, Juan,Garcia-Belmonte, Germà The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.44
<P>To increase the reversible capacity of layered lithium nickel-cobalt-manganese oxide, a Li[Ni0.8Co0.06Mn0.14]O2positive electrode with a two-sloped full concentration gradient (TSFCG) was successfully synthesized<I>via</I>co-precipitation. The TSFCG maximizes the Ni concentration in the particle core and the Mn concentration on the particle surface. The TSFCG Li[Ni0.8Co0.06Mn0.14]O2positive electrode showed improved overall electrochemical properties (<I>i.e.</I>, reversible capacity, cycle life, and rate capability) and thermal stability compared to a conventional positive electrode (CC) Li[Ni0.8Co0.06Mn0.14]O2without a concentration gradient. Electrochemical impedance spectroscopy showed that the high stability of the outer surface composition of Li[Ni0.64Co0.06Mn0.30]O2is responsible for reduction in surface resistance and charge transfer resistance by decreasing the parasitic reaction with the electrolyte. These reduced resistances explain the superior rate capability of TSFCG positive electrodes.</P>
Moises Bustamante-Pozo,Israel Ramirez-Sanchez,Alejandra Garate-Carrillo,Bruce Ito,Viridiana Navarrete,Moises Haro,Ricardo Garcia,Nancy Carson,Guillermo Ceballos,Francisco Villarreal 한국식품영양과학회 2022 Journal of medicinal food Vol.25 No.8
One of the most abundant flavonoids present in cacao is (−)-epicatechin (Epi) and this flavanol has been linked to the cardiovascular health promoting actions of cocoa products. We previously demonstrated that Epi reduces infarct size in rodent models of ischemia/reperfusion and permanent coronary occlusion. Reduced infarct size was associated with decreased left ventricular (LV) oxidative stress (OS) and indicators of inflammation factors, which foster myocardial fibrosis. In this study, we examine the antifibrotic actions of Epi in an aging female rat model of pre-heart failure with preserved ejection fraction (pre-HFpEF) as well as its potential to mitigate plasma levels of OS, proinflammatory/profibrotic cytokines, and improve passive and active LV function. Epi treatment [1 mg/(kg·d)] was provided daily by gavage from 21 to 22 months of age, whereas controls received water. A Millar catheter was used to assess hemodynamic function. Subsequently, hearts were arrested in diastole, a balloon inserted into the LV and passive pressure–volume curves generated. Fixed LV sections were processed for collagen area fraction quantification using Sirius Red staining. Treatment with Epi did not lead to detectable changes in LV contractile function. However, passive LV pressure volume curves were significantly right shifted with Epi. Collagen area fraction values indicated that Epi treatment significantly reduces LV fibrosis. Epi also significantly reduced plasma OS markers and levels of profibrotic and proinflammatory cytokines. In conclusion, Epi reduces cardiac fibrosis in an aged, female rat model of pre-HFpEF, which correlates with significant reductions in OS and cytokine levels in the absence of changes in LV contractile function.