Browsing by Author "Caicedo, Carolina"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Bio- energía trabajo muscular y respiración en la córnea(Informador Técnico, 2018) del Castillo, Luis F.; Ramírez-Calderón, Juanibeth G.; Caicedo, Carolina; Ávila-Torres, Yenny; Caicedo-Cano, Diego F.; Compañ, VicenteResumen En este artículo de revisión se presentan dos casos del área de bioenergía en relación con la producción de energía vía descomposición del trifosfato de adenosina (ATP). El primero, es el trabajo que realiza el cuerpo humano debido a la contracción del músculo esquelético y el segundo el proceso de difusión de oxígeno en la córnea. Se exponen los antecedentes químico-físicos de la producción y utilización de la molécula energética por excelencia del ATP. Se analizan desde el punto de vista termodinámico, la generación de moléculas bioenergéticas tanto en la respiración aeróbica como en glicólisis anaeróbico. En este sentido, se presentan los procesos de biosíntesis para la utilización de la energía que almacenan las moléculas de ATP y se describe el transporte activo de moléculas en contra de gradientes de concentración. El transporte vesicular de proteínas, la permeabilidad de iones a través de las membranas envolventes a las paredes celulares por medio de las denominadas bombas de sodio-potasio. Posteriormente, se establecen algunos detalles acerca de los mecanismos por medio de los cuales se da la contracción muscular, haciendo referencia a la estructura de las fibras musculares. En el segundo caso, se muestra el estudio de la fisiología de la córnea, donde también se genera trabajo químico para mantener su transparencia a la luz, proveniente del exterior del ojo. Lo que conlleva a la conservación de la estructura adecuada de las células del endotelio, estroma y epitelio. Así mismo, se ilustra el requerimiento de trabajo osmótico para mantener el balance del pH en la córnea, cuando se encuentra con una deficiencia de oxígeno. En tal circunstancia se genera un flujo contra osmótico desde el humor acuoso hacia el estroma que tiende a contrarrestar el aumento de acidez.Item Design, theoretical study and correlation of the electronic and optical properties of diethynylphenylthiophene as photovoltaic materials(Elsevier B.V., 2019-09-26) Suarez, Melissa; Caicedo, Carolina; Morales, Jimmy; Flórez López, Edwin; Ávila Torres, YennyIn this work the authors reported the design of molecules with low molecular weight, which can be used in environmental applications. The systems are derived of diethynylphenylthiophene (LMWOM) coupled to phenyldiamine as spacer, forming hyper conjugated macrocycles (p-PDT, m-PDT, o-PDT, p-ZnPDT, m -ZnPDT and o-ZnPDT). Similar structures are used as sensitized materials in photovoltaic cells. The optical, geometric, electronic and photovoltaic properties was estimate using DFT, base B3LYP 6–31g (d, 2p) in Gaussian 09, software of quantum chemistry. The experimental correlation was calculated thorough of electrochemical analyses for HOMO, LUMO and GAP parameters. The results obtained to allow a rationalization or explanation of the experimental data. On the other hand, the acid Lewis effect was considered incorporating zinc(II) to lineal and macrocycle structures. The best photovoltaic parameters were described for the p-PDT molecule with PCE 26.18%, Jsc = 14.79 mA cm2 and ΔE = 2.66 eV. Also, they were also observed electronic effects in the stabilization of macrocycle, influenced by the isomer spacer. The metal ion presented three effects between lineal and macrocycle structures: To improve the electronic distribution between donor and acceptor, provides rigidity to the system favoring the optical and electronic properties and decreases GAP value. Finally, the authors correlate experimentally the method used theoretically, and it are proposed molecules with competitive properties in relationship to organic systems used as photosensitized materials, currently.Item Rheological, thermal, superficial, and morphological properties of thermoplastic achira starch modified with lactic acid and oleic acid(MDPI AG, 2019-12-04) Caicedo, Carolina; Aguirre Loredo, Rocío Yaneli; Fonseca García, Abril; Hernán Ossa, Omar; Vázquez Arce, Aldo; Calambás Pulgarin, Heidy Lorena; Ávila Torres, YennyThe modification of achira starch a thermoplastic biopolymer is shown. Glycerol and sorbitol, common plasticizers, were used in the molten state with organic acids such as oleic acid and lactic acid obtaining thermodynamically more stable products. The proportion of starch:plasticizer was 70:30, and the acid agent was added in portions from 3%, 6%, and 9% by weight. These mixtures were obtained in a torque rheometer for 10 min at 130 °C. The lactic acid managed to efficiently promote the gelatinization process by increasing the available polar sites towards the surface of the material; as a result, there were lower values in the contact angle, these results were corroborated with the analysis performed by differential scanning calorimetry and X-ray diffraction. The results derived from oscillatory rheological analysis had a viscous behavior in the thermoplastic starch samples and with the presence of acids; this behavior favors the transitions from viscous to elastic. The mixture of sorbitol or glycerol with lactic acid promoted lower values of the loss module, the storage module, and the complex viscosity, which means lower residual energy in the transition of the viscous state to the elastic state; this allows the compounds to be scaled to conventional polymer transformation processes.