The ACTH test in the diagnosis of hirsutism

The ACTH test has been used to confirm the diagnosis of adrenal insufficiency and the classic and the non-classic adrenal hyperplasia due to the 3-HSD, 21 OH e 110H deficiencies. This article reviews the historical aspects of the use of ACTH in the diagnosis of hirsutism and points out its mains indications. In spite of new biological molecular advances in the diagnosis of adrenal enzymatic deficiencies, the use of the ACTH test can help the physician to predict both genothipus and fenothipus in populations with hyperandrogenic manifestations due to non-classical or late-onset congenital adrenal hyperplasia.     

Characterization of the surface redox process of adsorbed morin at glassy carbon electrodes

The thermodynamic and kinetics of the adsorption of morin (MOR) on glassy carbon (GC) electrodes in 0.2 mol dm⁻³ phosphate buffer solutions (PBS, pH 7.00) was studied by both cyclic (CV) and square wave (SWV) voltammetries. The Frumkin adsorption isotherm was the best to describe the specific interaction of MOR with GC electrodes. The SWV allowed to characterize the thermodynamic and kinetics of surface quasi-reversible redox couple of MOR, using the combination of the “quasi-reversible maximum” and the “splitting of SW net peaks” methods. Average values obtained for the formal potential and the anodic transfer coefficient were (0.27 ± 0.02) V and (0.59 ± 0.09), respectively. Moreover, a value of formal rate constant (k_s) of 87 s⁻¹ for the overall two-electron redox process was calculated. The SWV was also employed to generate calibration curves, which were linear in the range MOR bulk concentration from 1.27 × 10⁻⁷ to 2.50 × 10⁻⁵ mol dm⁻³. The lowest concentration experimentally measured for a signal to noise ratio of 3:1 was 1.25 × 10⁻⁸ mol dm⁻³ (3 ppb).     

Potential options to reduce GHG emissions in Venezuela

This paper presents a summary of the technologies and practices that could be implemented in Venezuela in order to contribute to both climate change mitigation and national development efforts. The mitigation analysis concentrates on options to reduce CO₂ emissions generated from the energy sector and land-use change.

From the mitigation options analyzed for the energy sector it was determined that the most effective are those in the transportation sector (switching to larger capacity vehicles, reduced private vehicle share, and switching fuels for public transportation from gasoline to natural gas), both in terms of contribution to emissions reduction and costs. Regarding the options for industry, boilers conversion from liquids to natural gas shows negative cost, but to a considerably lower extent that for the transportation sector. Efficiency improvements of natural gas boilers, which presents close to zero cost, is more effective in reducing emissions than boiler conversion. Increase in hydro power generation is the alternative with the highest total cost but it is very effective in reducing emissions.

From the mitigation options analyzed for land-use change, it was established that the forest sector has a considerable potential for reducing CO₂ emissions through the adoption of sustainable forest practices, especially by slowing the rate of forest loss and degradation. Maintenance of already existing biomass in natural forests should be the first priority of forest measures to reduce the amount of carbon released to the atmosphere. Forest protection and management of native forest represent the two options with the highest carbon conservation potential and the lowest carbon unit cost. Expansion of the forest cover through the development of intensive forest plantations also presents a high potential to offset carbon emissions in Venezuela.

An analysis of the barriers to mitigation options implementation shows that in the energy sector, low energy prices represent the main barrier to any mitigation program. Another important limitation to mitigation strategies implementation is the lack of institutional capacity and legal instruments for developing the mitigation measures. In the forest sector the primary causes of forest clearing in the country are not related to forest activities, so the definition of feasible mitigation options will depend upon a good understanding of other economic sectors and how they account for land-use change. Land tenure, rural poverty, political interests, and weak implementation of land-use planning instruments and environmental laws are considered to be the key limitations to any effort dealing with forest conservation. Land tenure, economic factors, and lack of incentives represent some of the most important barriers to the development of forest plantations and agroforestry systems in the country.     

Activity coefficient acquisition with thermodynamics-informed active learning for phase diagram construction

This work explores the use of thermodynamics-informed Gaussian processes (GPs) and active learning (AL) to model activity coefficients and construct phase diagrams. Relying on synthetic data generated from an excess Gibbs energy model, GPs were found to accurately describe the activity coefficients of several binary mixtures across large composition and temperature ranges. Moreover, GPs could estimate their own uncertainty and identify composition/temperature regions where activity coefficient data provide the most information to the models. This was leveraged to build AL algorithms targeted at modeling phase equilibria. In many cases, a single active-learning-acquired data point was sufficient to describe the phase diagrams studied. Finally, the ability of AL to greatly reduce the amount of data needed to obtain accurate models was further verified on experimental case studies, namely individual ion activity coefficients, the solid–liquid and vapor–liquid equilibrium of deep eutectic solvents, and phase equilibria in ternary mixtures.