Gender-specific effects of HIV protease inhibitors on body mass in mice

Protease inhibitors, as part of highly active anti-retroviral therapy (HAART), have significantly increased the lifespan of human immunodeficiency virus (HIV) infected patients. Several deleterious side effects including dyslipidemia and lipodystrophy, however, have been observed with HAART. Women are at a higher risk of developing adipose tissue alterations and these alterations have different characteristics as compared to men. We have previously demonstrated that in mice the HIV protease inhibitor, ritonavir, caused a reduction in weight gain in females, but had no effect on male mice. In the present study, we examined the potential causes of this difference in weight gain. Low-density lipoprotein receptor (LDL-R) null mice or wild-type C57BL/6 mice, were administered 15 mug/ml ritonavir or vehicle (0.01% ethanol) in the drinking water for 6 weeks. The percent of total body weight gained during the treatment period was measured and confirmed that female LDL-R gained significantly less weight with ritonavir treatment than males. In wild type mice, however, there was no effect of ritonavir treatment in either sex. Despite the weight loss in LDL-R null mice, ritonavir increased food intake, but no difference was observed in gonadal fat weight. Serum leptin levels were significantly lower in females. Ritonavir further suppressed leptin levels in (p \u3c 0.05). Ritonavir did not alter serum adiponectin levels in either gender. To determine the source of these differences, female mice were ovariectomized remove the gonadal sex hormones. Ovariectomy prevented the weight loss induced by ritonavir (p \u3c 0.05). Furthermore, leptin levels were no longer suppressed by ritonavir (p \u3c 0.05). This study demonstrates that gonadal factors in females influence the hormonal control of weight gain changes induced by HIV protease inhibitors in an environment of elevated cholesterol

Phenomenological description of the nonlocal magnetization relaxation in magnonics, spintronics, and domain-wall dynamics

This is the final version of the article. Available from the American Physical Society via the DOI in this record.A phenomenological equation called the Landau-Lifshitz-Baryakhtar (LLBar) [Zh. Eksp. Teor. Fiz 87, 1501 (1984) [Sov. Phys. JETP 60, 863 (1984)]] equation, which could be viewed as the combination of the Landau-Lifshitz (LL) equation and an extra "exchange-damping" term, was derived by Baryakhtar using Onsager's relations. We interpret the origin of this exchange damping as nonlocal damping by linking it to the spin current pumping. The LLBar equation is investigated numerically and analytically for the spin-wave decay and domain-wall motion. Our results show that the lifetime and propagation length of short-wavelength magnons in the presence of nonlocal damping could be much smaller than those given by the LL equation. Furthermore, we find that both the domain-wall mobility and the Walker breakdown field are strongly influenced by the nonlocal damping.We acknowledge the financial support from EPSRC's DTC Grant No. EP/G03690X/1. W.W. thanks the China Scholarship Council for financial assistance. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement No. 247556 (NoWaPhen) and from the European Union's Horizon 2020 research and innovation program under Marie Skłodowska-Curie Grant Agreement No. 644348 (MagIC)

The x-ray microcalorimeter spectrometer onboard Athena

Trabajo presentado a la conferencia: "Space Telescopes and Instrumentation: Ultraviolet to Gamma Ray" celebrada en Amsterdam (Holanda) el 1 de julio de 2012.-- et al.One of the instruments on the Advanced Telescope for High-Energy Astrophysics (Athena) which was one of the three missions under study as one of the L-class missions of ESA, is the X-ray Microcalorimeter Spectrometer (XMS). This instrument, which will provide high-spectral resolution images, is based on X-ray micro-calorimeters with Transition Edge Sensor (TES) and absorbers that consist of metal and semi-metal layers and a multiplexed SQUID readout. The array (32 x 32 pixels) provides an energy resolution of < 3 eV. Due to the large collection area of the Athena optics, the XMS instrument must be capable of processing high counting rates, while maintaining the spectral resolution and a low deadtime. In addition, an anti-coincidence detector is required to suppress the particle-induced background. Compared to the requirements for the same instrument on IXO, the performance requirements have been relaxed to fit into the much more restricted boundary conditions of Athena. In this paper we illustrate some of the science achievable with the instrument. We describe the results of design studies for the focal plane assembly and the cooling systems. Also, the system and its required spacecraft resources will be given. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.Peer Reviewe

Impact of Kinetic Models on Methanol Synthesis Reactor Predictions: In Silico Assessment and Comparison with Industrial Data

The reactor is one of the most important equipment to be designed for optimal process operations. An appropriate reactor modeling leads to an efficient and optimal process conceptual design, simulation, and eventually construction. The key for success in this step is mainly related to kinetics. The present work is centered toward process simulation and aims at comparing three different kinetic models for methanol synthesis. The comparison shows how the refitted Graaf model, presented in a previous study, effectively predicts the performance of modern methanol synthesis loops. To pursue this objective, we simulated in Aspen HYSYS three methanol synthesis technologies (the most popular technologies in modern plants) and compared the results with industrial data. The proposed case study demonstrates that the refitted Graaf model is more accurate in output prediction than the well-established original Graaf and Vanden Bussche-Froment models, which are currently considered the industrial benchmark, thus showing how the refitted Graaf model is a potential candidate for future industrial applications

Process modeling and apparatus simulation for syngas production

Syngas is a versatile mixture containing H2, CO, and CO2. It is at the base of the industrial production of bulk chemicals such as ammonia, urea, methanol, synthetic fuel, and their derivatives. Syngas production still exploits natural gas, coal, and fossil fuels; however, alternatives are appearing for the next future. For instance, biomasses, solid fuels such as plastics and solid urban wastes are becoming more and more appealing. For industrial purposes, it is fundamental to properly model both reforming and gasification/pyrolysis processes so that to reliably predict the syngas mixture composition and quality. To do this, modeling and process simulation play a key role. In this chapter, the importance of the adopted mathematical tool will be proven showing that an appropriate selection is needed. For instance, ad-hoc numerical tools are developed to properly model both kinetic reactions and transport phenomena (i.e., mass and heat transfer) involved in gasification/pyrolysis processes. While, concerning the natural gas reforming, authors provide some hints in the mathematical modeling for the reforming furnace providing both complex models and simplified ones. The last part of the present chapter is devoted to the process simulation. Some examples are proposed and details on the implementation are provided. Finally, the authors report the digital twin (i.e., dynamic simulation) of a steam reforming furnace for biogas reforming proving the importance of a robust control loop and providing a reliable start-up procedure for the furnace unit

Smart implementation of bender equation of state

In this paper matrix and vector products are exploited to reformulate Bender Equation of State. Finally, the new formulation is used to generate results which has been compared with experimental data sets available in literature and the analogous findings coming from different thermodynamic packages commonly used in Aspen Hysys for Air Separation Unit

Century of Technology Trends in Methanol Synthesis: Any Need for Kinetics Refitting?

Recently, methanol has gained increasing attention thanks to the variety of feedstocks suitable for its production and its low environmental impact granting the molecule a key role in future economic roadmaps as in Olah’s development model. Nowadays, fossil sources are not the exclusive sources to produce syngas: biogas is a promising alternative, leading to less severe operating conditions and smaller plant scales. The most widespread kinetic models for methanol synthesis, namely, the Graaf and the Vanden Bussche–Froment models, will be proven not to be fully adequate in characterizing these conditions. A robust refit is shown to outperform predictions from conventional models and follow recent trends in process operations. The refitted Graaf model is more flexible on the operating conditions and feed compositions, removing also some infeasible discontinuities present in conventional models. The final result is a more generalized and accurate Graaf’s model for methanol synthesis on CZA catalysts