Browsing by Subject "Stability"

Now showing 1 - 15 of 15
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    A physicochemical, thermodynamical, structural and computational evaluation of kynurenic acid/cyclodextrin complexes
    (Elsevier, 2021-03-23) Matencio Durán, Adrián; Caldera, Fabrizio; Rubin Pedrazzo, Alberto; Monfared, Yousef Khazaei; Dhakar, Nilesh K.; Trotta, Francesco; Bioquímica y Biología Molecular A; Facultad de Biología
    In this work, the interaction between Kynurenic acid (KYNA) and several natural and modified cyclodextrins (CDs) is carried out. Among all the CD tested, HPβ-CD showed the strongest complexation constant (KF), with a value of 270.94 ± 29.80 M−1. Between natural (α- and β-) CDs, the complex of KYNA with β-CD was the most efficient. The inclusion complex of KYNA with CDs showed a strong influence of pH and temperature. The KF value decreased at high pH values, when the pKa was passed. Moreover, an increase of the temperature caused a decrease in the KF values. The thermodynamic parameters of the complexation (ΔH°, ΔS° and ΔG°) were studied with negative entropy, enthalpy and spontaneity of the process at 25 °C. Moreover, the inclusion complex was also characterized using FTIR and TGA. Finally, molecular docking calculations provided different interactions and their influence in the complexation constant.
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    Alteraciones en la presión plantar posterior a un protocolo de fatiga neuromuscular en máquina isoinercial
    (Universidad de Murcia, Servicio de publicaciones, 2021) Rodríguez Perdomo, Leonardo; Rincón Yepes, Camilo Andrés; Vargas Santiago, Miller Esneyder
    El objetivo del presente estudio fue establecer las diferencias que se presentan en la huella plantar tras aplicar un protocolo de fatiga neuromuscular. Un total de 10 deportistas varones sanos con una edad aproximada de 21 años fueron evaluados para el componente morfológico, con el equipo Tanita BC585F® (variables: kg de peso, kg de grasa, kg de músculo y kg de hueso). En el protocolo de fatiga se utilizó el equipo isoinercial Squat RSP®. Para la prueba de baropodometría, tanto en el pre-test como en el post-test, se utilizó el equipo EcoWalk. Se tomaron variables de presión R-Type® para ambos pies, como presión media, superficie de contacto, distribución anterior, posterior, lateral derecha y lateral izquierda. No se encontraron diferencias significativas en el pre y post test de la prueba de baropodometría con una p>0.05. Se encontraron correlaciones significativas entre el componente morfológico y la baropodometría con una p<0.05.
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    Bioceramic versus traditional biomaterials for endodontic sealers according to the ideal properties
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2024) Ortega, Miguel A.; Rios, Laura; Fraile Martínez, Oscar; Liviu Boaru, Diego; Leon Oliva, Diego De; Barrena Blázquez, Silvestra; Pereda Cerquella, Claude; Garrido Gil, Maria J.; Manteca, Luis; Buján, Julia; García Honduvilla, Natalio; Garcia Montero, Cielo; Rios Parra, Antonio
    Odontology, as a scientific discipline, continuously collaborates with biomaterials engineering to enhance treatment characteristics and patients' satisfaction. Endodontics, a specialized field of dentistry, focuses on the study, diagnosis, prevention, and treatment of dental disorders affecting the dental pulp, root, and surrounding tissues. A critical aspect of endodontic treatment involves the careful selection of an appropriate endodontic sealer for clinical use, as it significantly influences treatment outcomes. Traditional sealers, such as zinc oxide-eugenol, fatty acid, salicylate, epoxy resin, silicone, and methacrylate resin systems, have been extensively used for decades. However, advancements in endodontics have given rise to bioceramic-based sealers, offering improved properties and addressing new challenges in endodontic therapy. In this review, a classification of these materials and their ideal properties are presented to provide evidence-based guidance to clinicians. Physicochemical properties, including sealing ability, stability over time and space, as well as biological properties such as biocompatibility and antibacterial characteristics, along with costeffectiveness, are essential factors influencing clinicians' decisions based on individual patient evaluations.
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    Characterisation of the interaction among oil-in-water nanocapsules and mucin
    (MDPI, 2020-07-28) Collado-González, Mar; Kaur, Gurmeet; González-Espinosa, Yadira; Brooks, Rebecca; Goycoolea Valencia, Francisco Martín; Biología Celular e Histología
    Mucins are glycoproteins present in all mucosal surfaces and in secretions such as saliva. Mucins are involved in the mucoadhesion of nanodevices carrying bioactive molecules to their target sites in vivo. Oil-in-water nanocapsules (NCs) have been synthesised for carrying N,N0-(di-m-methylphenyl)urea (DMTU), a quorum-sensing inhibitor, to the oral cavity. DMTU-loaded NCs constitute an alternative for the treatment of plaque (bacterial biofilm). In this work, the stability of the NCs after their interaction with mucin is analysed. Mucin type III from Sigma-Aldrich has been used as the mucin model. Mucin and NCs were characterised by the multi-detection symmetrical flow field-flow fractionation technique (AF4). Dynamic light scattering (DLS) and z-potential analyses were carried out to characterise the interaction between mucin and NCs. According to the results, loading DMTU changes the conformation of the NC. It was also found that the synergistic interaction between mucin and NCs was favoured within a specific range of the mucin:NC ratio within the first 24 h. Studies on the release of DMTU in vitro and the microbial activity of such NCs are ongoing in our lab.
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    Complex polysaccharide-based nanocomposites for 2 oral insulin delivery
    (MDPI (Basel, Switzerland), 2020-01-15) Collado-González, Mar; Freitas, Alessandra R.; Santos, Ana Claudia; Ferreira, Nuno F.; Ferreri, Maria Cristina; Sequeira, Joana A.D.; Díaz Baños, F. Guillermo; Víllora Cano, Gloria; Veiga, Francisco; Ribeiro, Antonio; Carissimi, Guzmán; Química Física
    Polyelectrolyte nanocomposites rarely reach a stable state and aggregation often occurs. Here, we report the synthesis of nanocomposites for the oral delivery of insulin composed of alginate, dextran sulfate, poly-(ethyleneglycol) 4000, Poloxamer 188®, chitosan, and BSA. Chitosan seems to be essential for the final size of the nanocomposites. When the chitosan concentration used in the synthesis is 10-4 gcm-3, nanocomposites, microcomposites and milimetric composites are obtained. Reducing the chitosan concentration to 10-5 or 10-7 gcm-3 yields nanocomposites of 400-600 nm or 800-900 nm hydrodynamic diameter, respectively, measured by DLS. According to our results, the molecular weight of chitosan has little influence on the size of the composites. The enhanced stability of the newest nanocomposites synthesized was assessed with LUMiSizer®. The rounded shapes of the nanocomposites were confirmed by scanning electron microscopy. Analysis by HPLC revealed that, after loaded with insulin, about 80% of the drug was released from our nanocomposites.
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    Evaluation of juice and milk “food models” fortified with oxyresveratrol and β-Cyclodextrin
    (Elsevier, 2019-07-25) Navarro Orcajada, Silvia; Muñoz Sánchez, Iván; Laveda Cano, Lorena; Cano Yelo, Desiré; Matencio Durán, Adrián; Conesa Valverde, Irene; López Nicolás, José Manuel; García Carmona, Francisco; Bioquímica y Biología Molecular A
    Despite being saturated, a huge quantity of “novel” functional food products reaches the food market every day and companies are looking for new products to catch consumers’ attention. In the present study, the inclusion complexes of oxyresveratrol with α-, β- and γ-CD are characterized using DSC, TGA, SEM and molecular docking and their complexing capacities arecompared. As β-CD showed the best results, i) 0.2mM oxyresveratrol alone, ii) 0.2mM oxyresveratrol complexed with 8mM β-CD and iii) 4mM oxyresveratrol solubilized with 8mM β-CD were used to fortify, juice and milk food models, and kept in typical storage conditions (darkness and/or refrigerated) conditions for one month. The results showed that CD supplementation leads to a higher oxyresveratrol concentration and antioxidant capacity than when not used. Oxyresveratrol/β-CD food models were stable for five weeks. The most typical variables measured were compared. In vitro digestion pointed to similar bioaccessibility. The bacteriostatic effect was also studied and the greater effectiveness of oversaturated solutions was demostrated. These results should be useful for the food industry for designing hydrophilic products containing oxyresveratrol.
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    Examen de Certificación de la Sociedad Argentina dePediatría. El desafío de la evaluación remota
    (Universidad de Murcia. Servicio de publicaciones, 2024) Pascual, Carolina; Martínez Valenti, Ana María; Pose, Mónica Nancy; Yulitta, Horacio
    Introducción. La Sociedad Argentina de Pediatría (SAP) es una entidad certificante dePediatría y 21 Especialidades Pediátricas. El examen de certificación constituye una evaluaciónvoluntaria, independiente y desprovista de conflicto de interés. La herramienta utilizada para estaevaluación implica un desarrollo que comienza mucho antes de ejecutarla, con la elaboración de losinstrumentos a utilizar, y finaliza luego de su ejecución, con el análisis de los resultados y lavaloración de su funcionamiento. Objetivo. Presentar el proceso que el Consejo de EvaluaciónProfesional (CEP) de la SAP lleva a cabo para la certificación en Pediatría y EspecialidadesPediátricas y su transformación hacia un examen completamente remoto. Método. Descripción delas estrategias implementadas por el CEP para la elaboración de los exámenes de certificación y latransformación de estos a la modalidad remota. Se detallan los procesos de elaboración depreguntas de opción múltiple para el examen escrito y de casos semiestructurados para el oral, asícomo la implementación de un examen informatizado y remoto utilizando la plataforma Zoom y elnavegador seguro SEB (Safe Exam Browser). Resultados. Se implementó el examen de certificacióncompletamente remoto a 1586 profesionales, 752 correspondientes a certificación en pediatría y 834a especialidades pediátricas, entre los años 2020 y 2023. Se presentaron eventos catastróficos queincluyeron la interrupción de la conexión de internet y dificultades en la velocidad de circulación delas preguntas del examen de opción múltiple para los cuales se desarrollaron oportunamenteestrategias que permitieron salvar los incidentes referidos. Se tomaron encuestas a postulantes yjurados. Conclusión. La reorganización de la estrategiade ejecución del examen en una modalidadremota, con la implementación de tácticas específicas para salvar posibles situaciones catastróficas,permitió lograr un examen seguro, estable, con adecuada fluidez en su desarrollo y con altosíndices de aceptabilidad tanto para los que rinden como para los que toman exámenes deCertificación de la Sociedad Argentina de Pediatría
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    Highly selective biocatalytic synthesis of monoacylglycerides in sponge-like ionic liquids
    (RSC, 2017) Gómez, Celia; Sánchez-Gómez, Gregorio; García-Verdugo, Eduardo; Luis, Santiago V.; Lozano Rodríguez, Pedro; Nieto Cerón, Susana; Bioquímica y Biología Molecular B e Inmunología
    The biocatalytic synthesis of monoacylglycerides (MAGs) was carried out by the direct esterification of fatty acids (i.e. oleic, palmitic, myristic and lauric acids, respectively) with glycerol in different ionic liquids (ILs) based on cations with long alkyl side-chains (i.e. 1-hexadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C16mim][NTf2], 1-dodecyl-3-methylimidazolium tetrafluoroborate [C12mim][BF4]). Although all ILs have been shown as suitable reaction media for Novozym 435-catalyzed esterification of glycerol with free fatty acid, a highly selective selectivity of MAGs was only observed for the [C12mim][BF4] case (i.e up to 99% selectivity and yield for the monolaurin case). Furthermore, as these ILs are temperature switchable ionic liquid/solid phases that behave as sponge-like system, a straightforward protocol for IL-free MSGs recovery, based on iterative centrifugations at controlled temperature, has been developed.
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    Impact of stability on the performance of Persian Gulf Pro League football clubs
    (Murcia: Servicio de publicaciones de la Universidad de Murcia, 2020) Hosseini Keshtan, Misaq; Fazel Bakhsheshi, Mahmoud; Zareian, Hossein; Reihani, Mohammad
    The objective of this study was to determine the impact of sta-bility/instability on the performance of Persian Gulf Pro League football clubs. All the clubs that had participated in more than 3 seasons of the last 17 seasons (2001-2019) of the Persian Gulf Pro League were analyzed in this study (n=26). The performance of each team (improvement or worse-ning in ranking) and their stability were analyzed year after year in the pe-riod 2001-2019. The stability was divided in four components: CEO, head coach, players and club. The statistical analysis was performed with the software SPSS. Stability significantly (p<0.05) increased performance and instability significantly (p<0.05) decreased performance of the clubs in the four components studied: CEO, head coach, players and club. Therefore, it is expected that the results of this study encourage Iranian football clubs to increase their stability
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    Mutation stability in primary and metastatic melanoma: what we know and what we don’t
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2015) Varada, Sowmya; Mahalingam, Meera
    Despite the efficacy and success of targeted therapies, a significant number of patients with melanoma exhibit either intrinsic or acquired resistance to these drugs. Numerous mechanisms for the development of resistance have been postulated, but the precise reason for this is not known. In this review, we examine the incidence of mutations in select genes (BRAF, NRAS, C-KIT, and GNAQ) known to occur in melanoma, specifically in primary tumors and their paired metastases, to understand the significance of intratumoral heterogeneity by assessing how changes in mutation status alters the process of metastatic spread. Our data revealed a small yet consistent degree of discordance of mutations in the MAPK pathway commonly occurring in melanoma indicating that failed targeted therapy may be a consequence of this.
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    Polymeric Inclusion Membranes Based on Ionic Liquids for Selective Separation of Metal Ions
    (MDPI, 2023) Hernández-Fernández, Adrián; Iniesta-López, Eduardo; Ginestá-Anzola, Anahí; Garrido, Yolanda; Pérez de los Ríos, Antonia; Quesada-Medina, Joaquín; Hernández-Fernández, Francisco José; Ingeniería Química
    In this work, poly(vinyl chloride)-based polymeric ionic liquid inclusion membranes were used in the selective separation of Fe(III), Zn(II), Cd(II), and Cu(II) from hydrochloride aqueous solutions. The ionic liquids under study were 1-octyl-3-methylimidazolium hexafluorophosphate, [omim+][PF6-] and methyl trioctyl ammonium chloride, [MTOA+][Cl-]. For this purpose, stability studies of different IL/base polymer compositions against aqueous phases were carried out. Among all polymer inclusion membranes studied, [omim+][PF6-]/PVC membranes at a ratio of 30/70 and [MTOA+][Cl-]/PVC membranes at a ratio of 70/30 were able to retain up to 82% and 48% of the weight of the initial ionic liquid, respectively, after being exposed to a solution of metal ions in 1 M HCl for 2048 h (85 days). It was found that polymer inclusion membranes based on the ionic liquid methyl trioctyl ammonium chloride allowed the selective separation of Zn(II)/Cu(II) and Zn(II)/Fe(III) mixtures with separation factors of 1996, 606 and, to a lesser extent but also satisfactorily, Cd(II)/Cu(II) mixtures, with a separation factor of 112. Therefore, selecting the appropriate ionic liquid/base polymer mixture makes it possible to create polymeric inclusion membranes capable of selectively separating target metal ions.
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    Saliva chromogranin A in growing pigs: a study of circadian patterns during daytime and stability under different storage conditions
    (Elsevier, 2014-01-17) Escribano Tortosa, Damián; Gutiérrez Montes, Ana María; Fuentes Rubio, María; Cerón Madrigal, José Joaquín; Producción Animal
    Salivary chromogranin A (CgA) is considered to be a biomarker of activation of the sympatho-adrenome- dullary system, and has recently been proposed as a useful indicator of the acute stress response in pigs. The aim of the present study was to determinate whether salivary CgA concentrations in healthy growing pigs exhibits any circadian pattern during the daytime, and to evaluate its stability under different stor- age conditions. A total of 80 pigs (40 in spring and another 40 in autumn) of two different ages and gen- ders were used. To establish the circadian pattern, saliva samples were collected at 07.00, 11.00, 15.00 and 19.00 h on two consecutive days. Pooled samples were used for the stability study and were mea- sured on the day of sampling and periodically for up to 360 days later. Samples were stored at 4 °C, 20 °C or 80 °C and the effect of repeated freezing and thawing was also evaluated. No circadian pattern was detected for salivary CgA in either season and there were no significant effects of gender or age. However, mean salivary CgA concentrations were significantly higher (P < 0.0001) in the pigs sampled in autumn, compared to those sampled in the spring. Short term storage at 4 °C is recom- mended for up to 2 days, whereas frozen samples can be stored for 1 year at 20 °C or 80 °C, without substantial reduction in CgA values. In addition, samples can be frozen and thawed up to seven times without significant loss of the biomarker.
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    The state of the art in post-mortem redistribution and stability of new psychoactive substances in fatal cases: a review of the literature
    (MDPI, 2024-12-04) Menéndez-Quintanal, Luis Manuel; Matey, José Manuel; Fresno González, Violeta del; Bravo Serrano, Begoña; Hernández-Díaz, Francisco Javier; Montalvo, Gemma; García-Ruiz, Carmen; Zapata Arráez, Félix; Química Analítica; Facultad de Química
    In post-mortem (PM) investigations, forensic toxicologists attempt to identify legal or illegal substances present before death and determine how they contributed to the cause of death. A critical challenge is ensuring that PM sample concentrations accurately reflect those at the time of death, as postmortem redistribution (PMR) can alter these levels due to anatomical and physiological changes. The PMR phenomenon is called a ‘toxicological nightmare’. PMR significantly affects post-mortem drug concentrations, particularly for lipophilic drugs and those with a high volume of distribution. The emergence of new psychoactive substances (NPSs) has led to a growing recognition of their role as a significant public health concern, frequently associated with fatalities related to polydrug use. These substances are renowned for their ability to induce intoxication at low doses, which has led to the continuous updating of toxicological and forensic methods to improve detection and adopt new analytical standards. The comprehensive detection of NPS metabolites, some of which are still undiscovered, presents an additional analytical challenge, as do their metabolic pathways. This complicates their identification in fatal cases using standard analytical methods, potentially leading to an underestimation of their actual prevalence in toxicological results. Furthermore, the interpretation of analytical results is hindered by the absence of data on PM blood levels and the specific contributions of NPS to causes of death, exacerbated by the lack of knowledge of whether the PMR phenomenon influences them. This paper presents a comprehensive review of the literature on post-mortem cases involving various NPS, categorized according to classifications by the United Nations Office on Drugs and Crime (UNODC) and the European Union Drugs Agency (EUDA). These categories include cathinones, phenylethylamines, arylalkylamines, phencyclidine-type substances, phenmetrazines, piperazines, phenidates, aminoindanes, LSD-like NPSs, tryptamines, fentanyl analogs, designer benzodiazepines, synthetic cannabinoids, and nitazenes. This review covers not only postmortem blood levels but also the stability of the substances studied, the methods of analysis, and attempts to shed some light on the PMR phenomenon. This review used various key terms, such as PMR, NPS, and the names of previously categorized substances and drug analyses across multiple peer-reviewed journals and databases, including Scopus, Google Schoolar, Springer, PubMed, and Wiley Online Library. In addition, references from retrieved articles were examined to identify additional relevant research. Interpreting post-mortem toxicological results is complex and lacks definitive guidelines, requiring a nuanced understanding of its challenges and potential pitfalls. As a result, post-mortem toxicology is often regarded as an art. The primary aim of this review is to provide forensic toxicologists with a comprehensive framework to assist in the evaluation and interpretation of NPS analysis. This guide is intended to complement the existing knowledge and practices applied in forensic laboratories within the toxicological analysis of post-mortem cases.
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    Valor pronóstico de la densidad ósea y de la movilidad en el éxito implantológico
    (Sociedad Española de Cirugía Oral y Maxilofacial (SECOM), 2017) Moya Villaescusa, María José; Sánchez Pérez, Arturo Joaquín; Dermatología, Estomatología, Radiología y Medicina Física
    Objetivos: Evaluar el valor pronóstico de la movilidad primaria (momento de inserción del implante) y secundaria (fase protésica), así como el de la densidad ósea en el resultado de éxito o fracaso del implante durante un seguimiento continuado al año, a los 5 años y a los 10 años. Material y métodos: Se realizó un estudio longitudinal prospectivo con un seguimiento a 10 años en el que se incluyeron 151 implantes colocados en 71 pacientes, no fumadores, durante los años 2005 y 2006. A cada uno de los implantes se les midió las estabilidades primaria y secundaria a través de un valor Periotest® (VPT) y se anotó la densidad ósea presente en el momento de la implantación. De los 151 implantes colocados inicialmente, completaron el estudio 109. Resultados: No se observaron diferencias estadísticamente significativas respecto a la movilidad del implante en el momento de inserción o en la fase protésica y el éxito o fracaso del mismo al año, a los 5 años, o transcurridos 10 años desde su inserción. Sí encontramos diferencias estadísticamente significativas con relación al tipo de densidad ósea donde se colocó el implante a los 5 y 10 años (p < 0,05). Conclusiones: La movilidad primaria o secundaria del implante carece de valor pronóstico significativo sobre el éxito del mismo transcurridos 10 años desde su inserción. Por el contrario, la densidad de hueso inicial tiene una clara influencia en el éxito del implante a los 10 años, siendo más proclives al fracaso los huesos de alta densidad ósea. ----------------
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    Vida útil y beneficios de los nutracéuticos como alternativas al óxido de zinc
    (Universidad de Murcia. Servicio de publicaciones, 2024) Torralbo Martín, Andrea; Serrano Jara, Daniel; Cubero Pablo, María José; Jordán Bueso, María José; Martínez Conesa, Cristina; Rivera Gomis, Jorge
    El destete es una de las etapas más críticas en la producción porcina, con frecuentes diarreas. Se ha utilizado ampliamente el óxido de Zinc (ZnO), hasta su prohibición en Europa en 2022. Los compuestos bioactivos del orégano y el ajo morado fueron investigados por sus propiedades medicinales, y podrían ser alternativas al ZnO y a los antibióticos. Se compararon siete tratamientos dietéticos: un grupo control negativo (dieta basal), un grupo control positivo con ZnO (2500 mg/kg de alimento), dos grupos con aceite esencial de orégano al 0.4% y al 1.2% res-pectivamente, dos grupos con moltura de ajo morado al 0.4% y al 2% respectivamente, y un grupo con aceite esencial de orégano al 1.2% combinado con moltura de ajo morado al 2%. Los tratamientos se realizaron tras el destete a los 21 días, durante 2 semanas en el pre- estárter y durante 5 semanas en el estárter. Al finalizar las 10 semanas, los lechones se pesaron y se realizó la necropsia para tomar muestras de yeyuno e íleon y evaluar su morfometría. Hemos estudiado el impacto de la degradación de los nutracéuticos durante su almacenamiento en los silos, así como su repercusión sobre la morfometría del yeyuno e íleon y su influencia en la ganancia media diaria y el índice de conversión.Al evaluar la degradación de los compuestos bioactivos en los piensos, almacenados durante 5 semanas, se identificó una pérdida del 30% tanto en el orégano como en el ajo morado. No obstante, no hubo diferencias significativas en el rendimiento productivo y la morfometría intestinal entre el tratamiento con ZnO y el com-binado de moltura de ajo morado al 2% y el aceite esencial de orégano al 1.2%. En conclusión, estas dosis son una buena alternativa como promotores del crecimiento y para la prevención de la diarrea post- destete.