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The rheological and viscoelastic properties of hybrid formulations composed of vehicles designed for cutaneous topical application and loaded with ultradeformable liposomes (UDL) were assessed. UDL were selected for their established ability to transport both lipophilic and hydrophilic compounds through the skin, and are applicable in pharmaceuticals and cosmetics. Formulations underwent flow analysis and were fitted to the Herschel-Bulkley model due to their prevalent non-Newtonian behavior in most cases. Linear viscoelastic regions (LVR) were identified, and G' and G″ moduli were determined via frequency sweep steps, considering the impact of temperature and aging. The formulations exhibited non-Newtonian behavior with pseudoplastic traits in most cases, with UDL incorporation inducing rheological changes. LVR and frequency sweep tests indicated predominantly elastic solid behavior, with G' higher than G″, at different temperatures and post-production times. Tan δ values also illustrated a predominant solid-like behavior over liquid. This study provides pivotal insights into the rheological and viscoelastic features of topical formulations, emphasizing the crucial role of meticulous vehicle and formulation selection when incorporating UDL or analogous liposomal drug delivery systems.

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RESUMEN Introducción: Las fracturas abiertas del tercio distal de tibia o pilón son poco frecuentes, en nuestro medio se producen por traumas de alta energía como los accidentes de tránsito, y pueden ser de distintos grados según su envergadura. Entre las complicaciones frecuentes están la seudoartrosis, deformidades y artritis postraumática. Cuando el dolor es refractario a los analgésicos están indicadas las artrodesis. Objetivo: Presentar los resultados del tratamiento realizado en un paciente con seudoartrosis distal de tibia y artritis postraumática del tobillo, dolorosa, con gran lesión de partes blandas, por lo que fue imposible realizar los procedimientos quirúrgicos habituales. Presentación del caso: Se realizó artrodesis de las articulaciones tibio-peronea-astragalina-calcánea, mediante un injerto libre del peroné autólogo, compresión, y estabilización con un fijador externo RALCA®; se asoció un campo electromagnético pulsátil para acelerar la formación del callo óseo y disminuir el dolor posquirúrgico. Durante dos años se le hizo seguimiento. Conclusiones: Se logró el objetivo del tratamiento al fusionar la articulación tibiotarsiana, comenzar el apoyo precoz y su capacidad funcional. Los resultados demuestran además los beneficios de la compresión realizada con los fijadores externos en las artrodesis; el uso del campo electromagnético asociado aceleró la osteogénesis, se consiguió la consolidación ósea, la estabilización, disminuyó el edema y el dolor, además la reincorporación del paciente a la sociedad. No se encontró en la bibliografía revisada otra técnica quirúrgica similar(AU)

ABSTRACT Introduction: Open fractures of the distal third of the tibia or pilon are rare, in our environment they are caused by high-energy traumas such as traffic accidents, and can be of different degrees depending on their size. Common complications include nonunion, deformities, and post-traumatic arthritis. When pain is refractory to analgesics, arthrodesis is indicated. Objective: To report the results of the treatment carried out in a patient with distal tibial pseudoarthrosis and post-traumatic arthritis of the ankle, painful, with a large soft tissue injury, which made it impossible to perform the usual surgical procedures. Case report: Arthrodesis of the tibiofibular-talar-calcaneal joints was performed, using a free graft of the autologous fibula, compression, and stabilization with a RALCA® external fixator. A pulsatile electromagnetic field was associated to accelerate bone callus formation and reduce postoperative pain. This patient was followed up for two years. Conclusions: The treatment objective was achieved by fusing the tibiotarsal joint, by starting early support and functional capacity. The results also prove the benefits of compression performed with external fixators in arthrodesis. The use of the associated electromagnetic field accelerated osteogenesis, bone consolidation and stabilization were achieved, edema and pain decreased, as well as the patient's reincorporation into society. No other similar surgical technique was found in the reviewed literature(AU)

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Graph-theoretic matrix representations constitute the most popular and significant source of topological molecular descriptors (MDs). Recently, we have introduced a novel matrix representation, named the duplex relations frequency matrix, F, derived from the generalization of an incidence matrix whose row entries are connected subgraphs of a given molecular graph G. Using this matrix, a series of information indices (IFIs) were proposed. In this report, an extension of F is presented, introducing for the first time the concept of a hypermatrix in graph-theoretic chemistry. The hypermatrix representation explores the n-tuple participation frequencies of vertices in a set of connected subgraphs of G. In this study we, however, focus on triple and quadruple participation frequencies, generating triple and quadruple relations frequency matrices, respectively. The introduction of hypermatrices allows us to redefine the recently proposed MDs, that is, the mutual, conditional, and joint entropy-based IFIs, in a generalized way. These IFIs are implemented in GT-STAF (acronym for Graph Theoretical Thermodynamic STAte Functions), a new module of the TOMOCOMD-CARDD program. Information theoretic-based variability analysis of the proposed IFIs suggests that the use of hypermatrices enhances the entropy and, hence, the variability of the previously proposed IFIs, especially the conditional and mutual entropy based IFIs. The predictive capacity of the proposed IFIs was evaluated by the analysis of the regression models, obtained for physico-chemical properties the partition coefficient (Log P) and the specific rate constant (Log K) of 34 derivatives of 2-furylethylene. The statistical parameters, for the best models obtained for these properties, were compared to those reported in the literature depicting better performance. This result suggests that the use of the hypermatrix-based approach, in the redefinition of the previously proposed IFIs, avails yet other valuable tools beneficial in QSPR studies and diversity analysis.

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