220 research outputs found
System dynamics modelling in systems biology and applications in pharmacology
El modelado matemático de sistemas biológicos complejos es uno de los temas clave en la Biología de Sistemas y varios métodos computacionales basados en la simulación computarizada han sido aplicados hasta ahora para determinar el comportamiento de los sistemas no lineales. La Dinamica de Sistemas es una metodología de modelado intuitivo basada en el razonamiento cualitativo por el cual un modelo conceptual se puede describir como un conjunto de relaciones de causa y efecto entre las variables de un sistema. A partir de esta estructura, es posible obtener un conjunto de ecuaciones dinámicas que describan cuantitativamente el comportamiento del sistema. Centrándose en los sistemas farmacológicos, el modelado compartimental a menudo se utiliza para resolver un amplio espectro de problemas relacionados con la distribución de materiales en los sistemas vivos en la investigación, el diagnóstico y la terapia en todo el cuerpo, los órganos y los niveles celulares.
En este artículo presentamos la metodología de modelado de Dinámica del Sistema y su aplicación al modelado de un modelo compartimental farmacocinético-farmacodinámico del efecto de profundidad anestésica en pacientes sometidos a intervenciones quirúrgicas, derivando un modelo de simulación en el entorno de simulación orientada a objetos OpenModelica. La Dinamica de Sistemas se puede ver como una herramienta educativa poderosa y fácil de usar y en la enseñanza de Biología de Sistemas.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Post-synthetic ligand exchange as a route to improve the affinity of ZIF-67 towards CO2
The Zeolitic Imidazolate Framework 67 (ZIF-67) is a highly promising material owing to its exceptional thermal stability, large specific surface area, costeffectiveness,
and versatile applications. One of the potential applications of ZIF-67 is gas separation processes, among which the separation of CO2/CH4 mixtures
has attracted great interest nowadays in the biogas sector. However, when it comes to CO2/CH4 separation, ZIF-67 falls short as it lacks the desired selectivity
despite its high adsorption capacity. This limitation arises from its relatively low affinity towards CO2. In this study, we have addressed this issue by partially
exchanging the ligand of ZIF-67, specifically replacing 2-methylimidazole with 1,2,4 (1H) triazole, which introduces an additional nitrogen atom. This modification
resulted in ZIF-67 showing significantly enhanced affinity towards CO2 and, as a result, greater selectivity towards CO2 over CH4. The modified materials underwent
thorough characterization using various techniques, and their adsorption capacity was evaluated through high-pressure adsorption isotherms. Furthermore, their
separation performance was assessed using the Ideal Solution Adsorption Theory, which provided valuable insights into their potential for efficient gas separation
Four-channel self-compensating single-slope ADC for space environments
A multichannel high-resolution single-slope analogue-to-digital converter (SS ADC) is presented that automatically compensates for process, voltage and temperature variations, as well as for radiation effects, in order to be used in extreme environmental conditions. The design combines an efficient implementation by using a feedback loop that ensures an inherently monotonic and very accurate ramp generation, with high levels of configurability in terms of resolution and conversion rate, as well as input voltage range. The SS ADC was designed in a standard 0.35 μm CMOS technology. Experimental measurements of the performance and stability against radiation and temperature are presented to verify the proposed approach
A Front-End ASIC for a 3-D Magnetometer for Space Applications by Using Anisotropic Magnetoresistors
This paper presents an application-specific integrated circuit (ASIC) aimed for an alternative design of a digital 3-D magnetometer for space applications, with a significant reduction in mass and volume while maintaining a high sensitivity. The proposed system uses magnetic field sensors based on anisotropic magnetoresistances and a rad-hard mixed-signal ASIC designed in a standard 0.35 μm CMOS technology. The ASIC performs sensor-signal conditioning and analogue-to-digital conversion, and handles calibration tasks, system configuration, and communication with the outside. The proposed system provides high sensitivity to low magnetic fields, down to 3 nT, while offering a small and reliable solution under extreme environmental conditions in terms of radiation and temperature.Ministerio de Ciencia e Innovación AYA2011-29967-C05-05, AYA2009-14212-C05-04, AYA2008-06420-C04-0
Volcanic eruption of Cumbre Vieja, La Palma, Spain: a first insight to the particulate matter injected in the troposphere
The volcanic eruption of Cumbre Vieja (La Palma Island, Spain), started on 19 September 2021 and was declared terminated on 25 December 2021. A complete set of aerosol measurements were deployed around the volcano within the first month of the eruptive activity. This paper describes
the results of the observations made at Tazacorte on the west bank of the island where a polarized micro-pulse lidar was deployed. The analyzed two-and-a-half months (16 October–31 December) reveal that the peak height of the lowermost and strongest volcanic plume did not exceed 3 km (the
mean of the hourly values is 1.43 0.45 km over the whole period) and was highly variable. The peak height of the lowermost volcanic plume steadily increased until week 11 after the eruption started (and 3 weeks before its end) and started decreasing afterward. The ash mass concentration was
assessed with a method based on the polarization capability of the instrument. Two days with a high ash load were selected: The ash backscatter coefficient, aerosol optical depth, and the volume and
particle depolarization ratios were, respectively, 3.6 (2.4) Mm.
1 sr. 1 , 0.52 (0.19), 0.13 (0.07) and 0.23
(0.13) on 18 October (15 November). Considering the limitation of current remote sensing techniques to detect large-to-giant particles, the ash mass concentration on the day with the highest ash load
(18 October) was estimated to have peaked in the range of 800–3200 g m.
3
in the lowermost layer
below 2.5 km.This research was funded by the Spanish Ministry of Science and Innovation (PID2020-
118793GA-I00, PID2019-104205GB-C21, EQC2018-004686-P and PID2019-103886RB-I00), the H2020
program from the European Union (GA no. 19ENV04, 654109, 778349, 871115 and 101008004), and
the Unit of Excellence “María de Maeztu” (MDM-2017-0737) financed by the Spanish State Research
Agency (AEI)
OWLs: A mixed-signal ASIC for optical wire-less links in space instruments
This paper describes the design of a mixed-signal ASIC for space application and the techniques employed for radiation hardening and temperature effects compensation. The work is part of a planned long-term effort and collaboration between "Instituto de Microelectrónica de Sevilla (IMSE)", "Universidad de Sevilla (US)", and "Instituto Nacional de Técnica Aeroespacial (INTA)" aimed to consolidate a group of experienced mixed-signal space-ASIC designers. The initiative is partially funded by the Spanish National Research Program. The ASIC performs the function of an optical digital transceiver for diffuse-light intra-satellite optical communications. It has been designed in a 0.35μm CMOS technology from austriamicrosystems (ams). The chip has been manufactured and verified from a functional perspective. Radiation characterization is planned for the third quarter of 2012. Power- and temperature-stress tests, as well as life-tests are also planned for this next quarter, and will be carried out by Alter Technology TÜV Nord S.A.U. Given the previous characterization of the technology [1] and the hardening techniques employed in the design and layout, radiation is not expected to be a problem. The specified environmental limits are a pedestal hard limit of 50KRads with the goal of maximizing TID tolerance, SEU and SET LET-thresholds above 70MeV/(mg/cm2), and latchup free behavior up to the same LET limit. Concerning temperature, the specified operation range is from -90 to +125ºC, while the non-operating temperature range is from -135 to +150ºC.Ministerio de Ciencia e Innovación (MICINN) MEIGA AYA2009-14212-C05-04, AYA2008-06420-C04-0
Impact of a home telehealth program after a hospitalized COPD exacerbation: a propensity score analysis
[Abstract] Introduction: Currently there is lack of data regarding the impact of a home telehealth program on readmissions and mortality rate after a COPD exacerbation-related hospitalization.
Objective: To demonstrate if a tele-monitoring system after a COPD exacerbation admission could have a favorable effect in 1-year readmissions and mortality in a real-world setting.
Methods: This is an observational study where we compared an intervention group of COPD patients treated after hospitalization that conveyed a telehealth program with a followance period of 1 year with a control group of patients evaluated during one year before the intervention began. A propensity-score analyses was developed to control for confounders. The main clinical outcome was 1-year all-cause mortality or COPD-related readmission.
Results: The analysis comprised 351 telemonitoring patients and 495 patients in the control group. The intervention resulted in less mortality or readmission after 12 months (35.2% vs. 45.2%; hazard ratio [HR] 0.71 [95% CI=0.56-0.91] 0.71 [95% CI=0.56-0.91; p=0.007). This benefit was maintained after the propensity score analysis (HR=0.66 [95% CI=0.51-0.84]). This benefit, which was seen from the first month of the study and during its whole duration, is maintained when mortality (HR=0.54; 95% CI=[0.36-0.82]) or readmission (subdistribution hazard ratio [SHR] 0.66; 95% CI=[0.50-0.86]) are analyzed separately.
Conclusion: Telemonitoring after a severe COPD exacerbation is associated with less mortality or readmissions at 12 months in a real world clinical setting
Meliaceae (Sapindales): riqueza y distribución en el estado de Tabasco, México
Background and Aims: In order to update the checklist of Meliaceae that occur in the state of Tabasco under the current classification system, a taxonomic review of the family was conducted, contributing to the “Flora de Tabasco” project.Methods: A revision of specimens belonging to Meliaceae was performed in both state and national herbaria. Field work was carried out between 2015 and 2017 sampling a wide array of of natural and secondary vegetation types in Tabasco. The collected material was identified with the use of taxonomic keys and compared with reliably identified herbarium material. Type specimens available in JSTOR Global Plants were also consulted. We provide an identification key for the species of the family in Tabasco. We also performed an analysis of the distribution of the species based on vegetation type and ecological data. Finally, we provide a list of common names and images of several species.Key results: The Meliaceae are represented by 11 species and four native genera; there are also two alien genera (each represented by a single species). Two species constitute new records for the flora of Tabasco. Trichilia is represented by seven species, whereas Guarea has two. The municipalities with the highest number of species are Centro and Teapa with eight species each and Balancán with seven species. Conclusions: The Meliaceae species reported for the study area represent 45.83% of the 24 native species of this family known in Mexico. They are mostly distributed in areas of secondary vegetation and remnants of tropical rain forest close to the borders with Chiapas and Guatemala.Antecedentes y Objetivos: Con la finalidad de actualizar el listado de especies de Meliaceae en el estado de Tabasco bajo el sistema de clasificación actual, se completó una revisión taxonómica de la familia, como contribución al proyecto “Flora de Tabasco”. Métodos: Se llevó a cabo una revisión en herbarios estatales y nacionales de los ejemplares de las especies de la familia Meliaceae y se realizaron colectas en campo de 2015 a 2017 en vegetación secundaria y primaria del estado. El material colectado fue identificado por medio de claves taxonómicas y cotejado con material de herbario. También se consultaron los ejemplares tipo disponibles en JSTOR Global Plants. Se hizo una clave de identificación para las especies de la familia en Tabasco y un análisis de distribución por tipo de vegetación y datos ecológicos; así mismo se registran nombres comunes y se ilustran algunas de las especies. Resultados clave: La familia Meliaceae está representada por 11 especies en cuatro géneros nativos y dos especies en dos géneros introducidos. Se registran por primera vez dos especies para el estado. El género Trichilia es representado por siete especies, seguido de Guarea con dos. Los municipios con el mayor número de especies son Centro y Teapa con ocho especies cada uno y Balancán con siete. Conclusiones: Las Meliáceas nativas presentes en la zona de estudio representan 45.83% de las 24 especies nativas estimadas para la familia en México y están distribuidas principalmente en áreas de vegetación secundaria y manchones de selva en municipios serranos fronterizos con Chiapas y Guatemala
Alternative Eco-Friendly Methods in the Control of Post-Harvest Decay of Tropical and Subtropical Fruits
The effectiveness on several fruits by the application of alternative methods against fungi is summarized in the present chapter. Several investigations have reported the efficacy of these technologies for controlling fungal infections. Currently, high post-harvest loses have been reported due to several factors such as inefficient management, lack of training for farmers, and problems with appropriate conditions for storage of fruits and vegetables. Even now, in many countries, post-harvest disease control is led by the application of chemical fungicides. However, in this time, awareness about fungi resistance, environmental, and health issues has led to the research of eco-friendly and effective alternatives for disease management. The pathogen establishment on fruits can be affected by the application of GRAS compounds like chitosan, essential oils, salts, among others; besides, their efficacy can be enhanced by their combination with other technologies like ultrasound. Thus, the applications of these alternatives are suitable approaches for post-harvest management of fruits
- …