Synthesis of Cyclopropyl Inhibitors of Invertebrate Sterol Metabolism

Marine sterols are of great research interest due to their diverse structural properties. Although these sterols have been isolated and characterized, little is known about their biological importance. Cholesterol is an important lipid in animals. Many invertebrates such as insects cannot synthesize cholesterol, however, they can transform plant sterols from their diet into cholesterol through a series of biochemical reactions that result in dealkylation at C-24. Petrosterol is a cyclopropyl sterol found in Petrosia ficiformis, a marine sponge.Recent studies have shown that petrosterol inhibits the dealkylation. Inhibiting the formation of cholesterol would have a negative impact on the health, growth and reproduction of copepods. The cyclopropyl group is known to lead to mechanism-based irreversible enzyme inhibition through the formation of cyclopropylcarbinyl cations and radical intermediates. This study focused on the synthesis of simplified analogs of petrosterol and its possible enzymatic products. Synthesis of simplified petrosterol analogs was completed following literature procedures and the structures of the compounds synthesized were determined by 1H, 13C, COSY, HMBC and HSQC NMR spectroscopy. Successful synthesis of 3 out of 4 simplified analogs was achieved and verified through NMR spectroscopy. Future work includes successful synthesis of the fourth analog and synthesis of these compounds with 13C labeling at the C-22 position. The 13C labeled sterols will be fed to invertebrates and tracked to better understand their mechanisms of action

Análisis de la influencia de las variables poblacionales en la evolución de los estudios de Informática

Fortich Giner, LJ. (2011). Análisis de la influencia de las variables poblacionales en la evolución de los estudios de Informática. http://hdl.handle.net/10251/11214.Archivo delegad

Refrigerant charge prediction fluctuations in the scop campaign of a brine-water heat pump

The refrigerant amount reduction is a matter of increasing importance because of the rise in prices of current hydrofluorocarbons and the safety reasons of the leading natural alternatives. There is no space for the refrigerant deposit in vapour compression cycles with refrigerant charge optimised; consequently, it is essential to know which refrigerant charge will make the vapour compression cycle work with the best performance during a year. In this work, a simulation of the different tests of the seasonal COP campaign for a brine-water heat pump is performed using the software IMST-ART. With the results, it can be possible to understand the different behaviour of the heat pump during the year and guess the best criteria to establish the optimum refrigerant charge.The authors are grateful to the Programa de Ayudas de Investigacion y Desarrollo (PAID-01- 17) to partially finance this research. As well, this publication has been carried out in the framework of the project “DECARBONIZACIÓN DE EDIFICIOS E INDUSTRIAS CON SISTEMAS HÍBRIDOS DE BOMBA DE CALOR”, funded by the Spanish “Ministerio de Ciencia e Innovación (MCIN) with code number PID2020- 115665RB-I00

Comparative study of the performance of a heat pump for heating with R410A and R32 as refrigerant, using the software IMST-ART

[EN] According to the European Commission, at this moment, heating and cooling in buildings account for half of the energy consumption, while only a 16% of the energy used in this issue is obtained employing renewable sources. One of the possible solutions to improve the current situation is the use of heat pumps for the air conditioning of buildings. However, the refrigerants used at this moment are hydrofluorocarbons (HFCs) and they have a global warming potential (GWP) elevated so that new refrigerants which can substitute the current ones are being searched. The most used refrigerant for heating applications is the R410A, which is a mixture of HFCs. Its immediate retrofit is one of its components, the R32, due to the compatibility of both refrigerants with the materials and its similar performance. Furthermore, the R32 has a value of GWP approximately of a third of the R410 s value. The objective of this work is to evaluate the main differences between the results obtained with both refrigerants and to find out the main changes to be done to obtain at least the same performance. In this work, a model of IMST-ART of an air-water heat pump is presented using both refrigerants. In the model, both refrigerants are evaluated for different conditions of heating at low temperature. Lately, a summary of changes is proposed in order to cover the same functions, or more, than the original heat pump.Luis Sánchez-Moreno-Giner acknowledges the Research and Development Aid Program (PAID01-17) of the Universitat Politècnica de València for receiving the Research Fellowship FPIUPV-2017.Sánchez-Moreno-Giner, L.; López-Juárez, E.; Gonzálvez-Maciá, J. (2019). Comparative study of the performance of a heat pump for heating with R410A and R32 as refrigerant, using the software IMST-ART. Universidad de Castilla-La Mancha José Antonio Almendros Ibáñez. 1135-1143. http://hdl.handle.net/10251/180704S1135114

Multilayer structures based on annealed electrospun biopolymer coatings of interest in water and aroma barrier fiber-based food packaging applications

In this research work, for the first time, a fiber-based packaging material was coated by annealed electrospun ultrathin fibers of poly(3-hydroxybutyrate), poly(vinyl alcohol), and polylactide. The resultant mono- and multilayer structures self-adhered to the paper substrate and were characterized in terms of morphology, optical, and barrier properties. Additionally, the use of a static flat plate and rotating mandrel collector as well as the application of different electrospinning deposition times were analyzed. The thermally treated electrospun biopolymers yielded totally transparent films while, due to the opaque nature of the uncoated paper substrate, the developed packaging materials were also opaque but with a glossier surface finish provided by the bioplastic coating. The annealed films obtained from random electrospun fibers, that is, the mats of ultrathin fibers collected on the static plate, presented higher transparency and thickness and also enhanced barrier performance. On the overall, the developed annealed electrospun biopolymer coatings resulted in a significant improvement of the paper barrier properties to water and limonene vapors, being the paper/poly(vinyl alcohol)/poly(3-hydroxybutyrate) film the best performing multilayer packaging structure

Thermodynamic assessment of ultra-low-global warming potential refrigerants for space and water heaters

[EN] The current paper studies the most suitable ultra-low-global warming potential (GWP) (GWP < 30) candidates in the market, considering also its grade of flammability and toxicity, for heat pumps employed for different space heating and domestic hot water (DHW) applications. A pre-design thermodynamic model has been developed to evaluate the performance and size limits for any subcritical or transcritical heat pump under certain working conditions. This generic model is based on the pinch point approach, so it does not depend on a certain type of heat exchangers, it only depends on the external working conditions. The results showed that all subcritical ultra-low-GWP, nonflammable, and nontoxic refrigerants considered have either lower coefficient of performance (COP) or volumetric heating capacity (VHC) compared with the reference high-GWP refrigerants R-410A and R-134a. Additionally, the only refrigerants with higher COP, such as R-717 (ammonia) or R-290 (propane), are either extremely flammable or toxic. For the applications need of high water-side temperature lift, the transcritical refrigerants R-744 (CO2) and R-170 (ethane) showed the best performance, regarding both COP and VHC values, of all the refrigerants studied. The refrigerants R-161, R-1270 (propylene), and R-1234yf presented a balanced performance in both space heating and DHW applications. This makes them potential candidates to be employed in subcritical multi-temperature levels heat pumps.This work was partially supported by the Research and Development Aid Program (PAID-01-17) of the Universitat Politecnica de Valencia for receiving the Research Fellowship FPI-UPV-2017. The authors also would like to acknowledge the financial support provided by the Ministerio de Ciencia, Innovacion y Universidades de Espana for the project "Maximizacion de la eficiencia y minimizacion del impacto ambiental de bombas de calor para la descarbonizacion de la calefaccion/acs en los edificios de consumo casi nulo" (ENE2017-83665-C2-1-P).Sánchez-Moreno-Giner, L.; López-Juárez, E.; Gonzálvez-Maciá, J.; Hassan, A. (2020). Thermodynamic assessment of ultra-low-global warming potential refrigerants for space and water heaters. Heat Transfer Research. 51(14):1317-1335. https://doi.org/10.1615/HeatTransRes.2020035317S13171335511

Experimental and Theoretical Analysis of Refrigerant Charge Extraction Methods

According to the European Commission, heating, cooling and domestic hot water (DHW) production implies 79% of the total energy consumed in households. Moreover, as 84% of this energy is still generated from fossil fuels, it is required taking measures in order to improve the current situation. One way to increase the decarbonization in households is the use of heat pumps powered by renewable energy sources. Additionally, the energy captured by heat pumps is considered renewable when a certain efficiency value is achieved (2009/28/CE directive). Nowadays, refrigerants used by heat pumps are mainly hydrofluorocarbons (HFCs) which have a high global warming potential (GWP) and have a clear deadline defined at F-Gas EU Regulation 517/2014. For this reason, natural refrigerants will play an important role within heating, cooling and DHW production at the household sector. However, most of the natural refrigerants with acceptable thermodynamic properties are at least slightly flammable or toxic, and its use has an associated risk due to this condition. That is the cause that the amount of refrigerant charge must comply with the maximum refrigerant charge limited by regulations, and the prediction of the nominal refrigerant charge amount inside a heat pump has become an important matter within the design process of a heat pump. There already exist prediction models of refrigerant charge but, under certain conditions, they do not fit the reality. The current prediction methods which use simulation models may be improved by knowing the actual distribution of the refrigerant inside the different components of a real heat pump. In order to empirically determine the refrigerant charge amount inside each part of the heat pump, several methods can be used, but the most employed one is the “remove and weight” technique. This technique consists in extracting the refrigerant charge of each element of the heat pump in a sample cylinder in order to weight it, after isolating each component from another. A similar but less precise approach of this method is employed when recovering refrigerant in maintenance or decommissioning tasks. In this contribution, a theoretical and experimental study of different charge extraction methods is presented. In the study, every method has been analyzed according to different factors: percentage of refrigerant extracted, security measures employed, the time needed until stability is reached and cost of the technique. The results of this study will help in the selection of best extraction method according to the precision of the results needed, the available resources and the training of the staff which in the end will be performing the experiments

V Congreso Internacional de Derechos Humanos y Derecho Procesal

El V Congreso Internacional de Derechos Humanos y Derecho Procesal que se ha desarrollado del 22 al 24 de marzo de 2011 en el Paraninfo de la Universidad de Murcia, se inició con el objetivo de aportar rigor científico a los temas más candentes del Derecho y, se ocupó en su dos primeras jornadas de los Derechos Humanos y en la última, de Derecho procesal. Con más de trescientos asistentes y numerosas personalidades del mundo político, social y cultural, entre las que destacan el Presidente de la Cámara de Comercio de Murcia, el Presidente de la Audiencia Provincial, el Jefe de la Policía Local de Murcia, el Coronel Jefe de la 5a zona de la Guardia Civil, el Teniente Coronel de la Academia General del Aire de San Javier, la Concejala de Seguridad Ciudadana del Ayuntamiento de Murcia y el Secretario General del Congreso y Presidente de la Asociación Colegial de Criminólogos de la Región de Murcia, Juan José Nicolas Guardiola

Development of formal dynamic models with Microsoft Excel for greenhouse climate control.

Simple climate models performed with a widespread computer tool (Microsoft® Excel) could be useful for researchers or even greenhouse growers. A model of this type was used in three independent studies (heating, ventilation and cooling). The error in the calculation of temperature was lower than 2.5 ºC, and the error in the calculation of relative humidity was lower than 9%, in the validation of the model. The main advantage of the method of modelling is the possibility of fitting the coefficients with the tool SOLVER of Microsoft® Excel in each greenhouse, an easy method for both scientist and growers