A stochastic model of the influence of buffer gas collisions on Mollow spectra

In this paper we consider the influence of collisional fluctuations on the Mollow spectra of resonance fluorescence (RF). The fluctuations are taken into account by a simple shift of the constant detuning, involved in a set of optical Bloch equations by collision frequency noise which is modelled by a two-step random telegraph signal (RTS). We consider in detail the Mollow spectra for RF in the case of an arbitrary detuning of the laser frequency, where the emitter is a member of a statistical ensemble in thermodynamic equilibrium with the buffer gas at temperature $T$ which is treated as a colored environment, and velocity $v$ is distributed with the Maxwell-Boltzmann density

A prediction of interfacial tension by using molecular dynamics simulation: A study on effects of cushion gas (CO2, N2 and CH4) for underground hydrogen storage

Carbon Dioxide (CO2) emissions from fossil fuel consumption have caused global warming and remain challenging problems for mitigation. Underground Hydrogen Storage (UHS) provides clean fuel and replaces traditional fossil fuels to reduce emissions of CO2. Geological formations such as depleted oil/gas reservoirs, deep saline aquifers and shale formations have been recognized as potential targets to inject and store H2 into the subsurface formations for large-scale implementation of CCS and UHS. However, the presence of H2 with cushion gas at different fractions under different geo-storage conditions, which can influence Hydrogen\u27s flow properties, was not investigated widely. Until now, studies of interfacial properties between water and a mixture of cushion gas (CO2, N2 or CH4) in the presence of H2 are very limited or unavailable data in experiments and simulations. In this study, many predictions by using molecular dynamics simulation were conducted to predict the interfacial tension ( ) for the systems of H2/CO2/H2O, H2/N2/H2O and H2/CH4/H2O at different pressures, temperatures, and fractions of cushion gases A comparison between the predicted γ results from the simulation and previous research were also made. The findings of this study indicated that γ of H2/CO2/H2O, H2/CH4/H2O, and H2/N2/H2O, as a function of pressure, temperature, and fraction of H2, decreased with increasing pressures and temperatures and increased with increasing H2% in the mixture. Additionally, an extending or new γ data in simulation for the CO2/H2/H2O, N2/H2/H2O and CH4/H2/H2O systems from this study were reported and support evaluating the stability and storage capacity of H2 combined with the cushion gas in geological formations. Furthermore, it can contribute to de-risking and proceeding safely and efficiently for the large-scale implementation of Underground Hydrogen Storage

Complete revascularization in coronary artery bypass grafting with coronary artery endarterectomy: updated findings from Vietnam

We examined the technique and early outcomes of coronary artery bypass graft surgery (CABG) with endarterectomy. In 2023, the single-center database identified 24 severe coronary disease patients undergoing CABG with coronary artery endarterectomy. The patients were in a selected cohort with a minimum of three grafts for the three main vessels. Patients’ mean age was 63.8 years. The mean number of grafts was 4.3. A coronary endarterectomy (CE) was performed on the right coronary artery in 45.8% of patients, the left anterior descending artery in 29.1%, the circumflex artery in 16.6%, and the diagonal artery in 29.1%. Aortic cross-clamp took 147.2 minutes, perfusion 180.9 minutes, mechanical ventilation 18.9 hours, and intensive care unit stay 4.8 days. Our in-hospital mortality rate was 8.3% with no technical complications. To achieve complete revascularization in patients with extensive coronary artery disease, CE should be considered an acceptable adjunct to CABG

Pulse propagation in an autoionization medium with double Fano profile

We discuss the propagation of a short laser pulse in an auto- ionizing (AI) medium with degenerate double Fano model. By solving numerically the coupled equations for atoms and fields we show that by the proper choice of Fano parameters involved in the problem (contrary to the case considered in (E. Paspalakis, N. J. Kylstra, and P. L. Knight, Phys. Rev. A60 (1999)) we have now two Fano asymmetry parameters) one can eliminate almost completely the absorption in the pulse propagation. It means that we have the transparency in the medium. From the connection between population trapping in short pulsed laser field and transparency in the propagation of the laser pulse which has been fixed by Paspalakis et al., Phys. Rev. A60 (1999) we conclude that this proper choice leads to the presence of the population trapping (or the existence of the “dark” states) in the atomic system. Moreover, instead of one value of the laser detuning for which the dark states exist in the case of one AI level, we find numerically two such values in the case of two AI levels

Alloy-free amorphous Pt–B–P/C electrocatalyst for enhanced methanol electro-oxidation

This study reports the first known demonstration of amorphous Pt–B–P/C achieved via electroless reduction without the need for additional unstable transition metals. The amorphous structure was induced by simultaneous dual doping of both B and P by electroless reduction of Pt ion solution using a simple and facile process at ambient conditions. Amorphous Pt–B–P/C exhibited superior specific, mass activity compared to both commercial PtRu/C and crystalline Pt–B–P/C. Durability and CO poisoning resistance were also found to be better. XPS and annealing results suggest that synergistic effect of both doping and amorphous structure of Pt–B–P/C led to its overall enhanced catalytic performance.Ministry of Education (MOE)Nanyang Technological UniversityThis work is supported by the Singapore Ministry of Education [MOE2017-T2-2-067] and NTUitive [NGF-2018-05-017]

p-Coumaric Acid Enhances Hypothalamic Leptin Signaling and Glucose Homeostasis in Mice via Differential Effects on AMPK Activation

AMP-activated protein kinase (AMPK) plays a crucial role in the regulation of energy homeostasis in both peripheral metabolic organs and the central nervous system. Recent studies indicated that p-Coumaric acid (CA), a hydroxycinnamic phenolic acid, potentially activated the peripheral AMPK pathway to exert beneficial effects on glucose metabolism in vitro. However, CA’s actions on central AMPK activity and whole-body glucose homeostasis have not yet been investigated. Here, we reported that CA exhibited different effects on peripheral and central AMPK activation both in vitro and in vivo. Specifically, while CA treatment promoted hepatic AMPK activation, it showed an inhibitory effect on hypothalamic AMPK activity possibly by activating the S6 kinase. Furthermore, CA treatment enhanced hypothalamic leptin sensitivity, resulting in increased proopiomelanocortin (POMC) expression, decreased agouti-related peptide (AgRP) expression, and reduced daily food intake. Overall, CA treatment improved blood glucose control, glucose tolerance, and insulin sensitivity. Together, these results suggested that CA treatment enhanced hypothalamic leptin signaling and whole-body glucose homeostasis, possibly via its differential effects on AMPK activation

<i>p</i>-Coumaric Acid Enhances Hypothalamic Leptin Signaling and Glucose Homeostasis in Mice via Differential Effects on AMPK Activation

AMP-activated protein kinase (AMPK) plays a crucial role in the regulation of energy homeostasis in both peripheral metabolic organs and the central nervous system. Recent studies indicated that p-Coumaric acid (CA), a hydroxycinnamic phenolic acid, potentially activated the peripheral AMPK pathway to exert beneficial effects on glucose metabolism in vitro. However, CA’s actions on central AMPK activity and whole-body glucose homeostasis have not yet been investigated. Here, we reported that CA exhibited different effects on peripheral and central AMPK activation both in vitro and in vivo. Specifically, while CA treatment promoted hepatic AMPK activation, it showed an inhibitory effect on hypothalamic AMPK activity possibly by activating the S6 kinase. Furthermore, CA treatment enhanced hypothalamic leptin sensitivity, resulting in increased proopiomelanocortin (POMC) expression, decreased agouti-related peptide (AgRP) expression, and reduced daily food intake. Overall, CA treatment improved blood glucose control, glucose tolerance, and insulin sensitivity. Together, these results suggested that CA treatment enhanced hypothalamic leptin signaling and whole-body glucose homeostasis, possibly via its differential effects on AMPK activation