A Novel Kinematic Model of the Tibiofemoral Joint Based on a Parallel Mechanism.

This paper presents a complete kinematic model of the tibiofemoral joint (TFJ) based on a RRPP + 4-SPS parallel mechanism, where R, P, and S stand for revolute, prismatic, and spherical joints, respectively. The model accounts for the contact between tibia and femur, and the four major ligaments: anterior cruciate, posterior cruciate, medial collateral, and lateral collateral, with anatomical significance in their length variations. An experimental flexion passive motion task is performed, and the kinematic model is tested to determine its capability to reproduce the workspace of the motion task. In addition, an optimization process is performed to simulate prescribed ligament length variations during the motion task. The proposed kinematic model is capable to reproduce with high accuracy an experimental three-dimensional workspace, and at the same time, to simulate prescribed ligament length variation during the spatial flexion task. Prescribed ligament length variations are achieved through an optimization process of the ligament insertion points. This model can be used to improve the multibody kinematic optimization (MKO) process during gait analysis, and also in the design of rehabilitation devices as well as trajectories to accelerate the recovery of injured ligaments. The model shows potential to predict ligament length variations during different motion tasks, and can serve as a basis to develop complex models for kinetostatic and dynamic analyses without dealing with computationally expensive models.

Membrane-mediated neuroprotection by curcumin from amyloid-ß-peptide-induced toxicity.

Amyloid-ß peptide (Aß)-membrane interactions have been implicated in the formation of toxic oligomers that permeabilize membranes, allowing an influx of calcium ions and triggering cell death in the pathogenesis of Alzheimer's disease (AD). Curcumin, a small dietary polyphenolic molecule, has been shown to reduce Aß-induced toxicity and AD pathology. We investigate here the effect of curcumin on Aß40-induced toxicity in cultured human neuroblastoma SH-SY5Y cells and test a novel neuroprotection mechanism in which curcumin reduces Aß-membrane interactions and attenuates Aß-induced membrane disruptions. Predominantly monomeric Aß40 exerts toxicity toward SH-SY5Y cells and has been shown to insert spontaneously into anionic lipid monolayers at the air/water interface, resulting in the misfolding and assembly of Aß into ß-sheet-enriched oligomers. Concomitantly, membrane morphology and lipid packing are disrupted. Curcumin dose-dependently ameliorates Aß-induced neurotoxicity and reduces either the rate or extent of Aß insertion into anionic lipid monolayers. Moreover, curcumin reduces Aß-induced dye leakage from lipid-bilayer-covered, dye-loaded, porous silica microspheres. Because curcumin neither affects the inherent surface activity of Aß nor modifies the membrane properties, it reduces Aß insertion by directly attenuating Aß-membrane interactions and reducing Aß-induced membrane disruption. Although the exact molecular mechanism of curcumin's membrane protective effect remains unclear, this effect could in part contribute to curcumin's neuroprotective effect with respect to Aß-induced toxicity. Our work reveals a novel molecular mechanism by which curcumin reduces Aß-related pathology and toxicity and suggests a therapeutic strategy for preventing or treating AD by targeting the inhibition of Aß-induced membrane disruption.

Clinical outcomes associated with Mu variant infection during the third epidemic peak of COVID-19 in Colombia.

BACKGROUND: The higher number of cases and deaths caused by COVID-19 in Colombia occurred during the third epidemic peak, where the Mu variant was associated with 50% of the cases. OBJECTIVE: To evaluate the association between the clinical outcome of COVID-19 with health conditions and SARS-CoV-2 lineages. METHODS: In this study, clinical metadata and SARS-CoV-2 lineages from 535 patients with different degrees of COVID-19 severity were obtained after the SARS-CoV-2 genomic surveillance in Colombia. Then, the associations between these variables were determined using a multidimensional unfolding analysis. RESULTS: Asymptomatic, symptomatic, severe, and deceased outcomes represented 15.2%, 29.7%, 7.3%, and 47.8% of the cases, respectively. Males tend to develop more serious COVID-19, and severe or fatal outcomes were typically observed in patients aged >60 years with comorbidities, including chronic obstructive pulmonary disease, heart disease, kidney disease, obesity, asthma, and smoking history. The SARS-CoV-2 Mu and Gamma variants dominated the third epidemic peak and accounted for most fatal cases with odd ratio values of 128.2 (CI 53.0-310.1) and 18.6 (CI 8.294-41.917). CONCLUSION: This study shows the high impact of SARS-CoV-2 lineages with higher prevalence on public health and the importance of monitoring COVID-19 risk factors to control the associated mortality.

Monkeypox virus genome sequence from an imported human case in Colombia. / Secuencia genómica del virus de la viruela símica de un caso importado en Colombia

INTRODUCTION: Monkeypox virus (MPXV) is an enveloped double-stranded DNA virus with a genome of approximately 197.209 bp. The current classification divides MPXV into three clades: Clade I (Central African or Congo Basin clade) and clades IIa and IIb (West African clades). OBJECTIVE: To report the complete genome and phylogenetic analysis of a human monkeypox case detected in Colombia. MATERIALS AND METHODS: Exudate from vesicular lesions was obtained from a male patient with recent travel history to Spain. A direct genomic approach was implemented in which total DNA from the sample was purified through a column-based method, followed by sequencing on the Nanopore GridION. Reads were aligned against the MPXV reference genome using minimap2 v.2.24 and phylogenetic inference was performed using maximum likelihood estimation. RESULTS: A total of 11.951 reads mapped directly to a reference genome with 96.8% of coverage (190.898 bp). CONCLUSION: Phylogenetic analysis of the MPXV circulating in Colombia demonstrated its close relationship to clade IIb responsible for the multi-country outbreak in 2022.

Introducción. El virus de la viruela del mono (MPXV) está compuesto por un genoma de ADN bicatenario, aproximadamente, de 197.209 pb. La clasificación actual agrupa el MPXV en tres clados: clado I (de la cuenca del Congo en África central), y clados IIa y IIb (de África occidental). Objetivo. Reportar el genoma completo y el análisis filogenético de un caso humano de viruela símica detectado en Colombia. Materiales y métodos. Se obtuvo exudado de lesiones vesiculares de un paciente varón con el antecedente de un viaje reciente a España. Se implementó un enfoque directo, en el cual se purificó el ADN total de la muestra mediante un método basado en columnas, seguido de la secuenciación directa en la plataforma Nanopore GridION. Las lecturas se alinearon con el genoma de referencia del MPXV, utilizando minimap2, v.2.24, y la inferencia filogenética fue realizada mediante la estimación por máxima verosimilitud. Resultados. Un total de 11.951 lecturas se alinearon directamente con el genoma de referencia con una cobertura del 96,8 % (190.898 pb). Conclusión. El análisis filogenético del MPXV circulante en Colombia demostró su estrecha relación con el clado de África occidental (clado IIb) responsable del brote en múltiples países en el 2022.

ROAD: domestic assistant and rehabilitation robot.

This study introduces the concept design and analysis of a robotic system for the assistance and rehabilitation of disabled people. Based on the statistical data of the most common types of disabilities in Spain and other industrialized countries, the different tasks that the device must be able to perform have been determined. In this study, different robots for rehabilitation and assistance previously introduced have been reviewed. This survey is focused on those robots that assist with gait, balance and standing up. The structure of the ROAD robot presents various advantages over these robots, we discuss some of them. The performance of the proposed architecture is analyzed when it performs the sit to stand activity.