Analgesic interpatient variability of remifentanil assessed through pupillary dilation reflex

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Pupillary pain index correlates with postoperative pain scores in neurosurgical patients

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Optimal dynamic control of laminated adaptive structures using a higher order model and a genetic algorithm

This paper deals with a finite element formulation based on the classical laminated plate theory, for active control of thin plate laminated structures with integrated piezoelectric layers, acting as sensors and actuators. The control is initialized through a previous optimization of the core of the laminated structure, in order to minimize the vibration amplitude. Also the optimization of the patches position is performed to maximize the piezoelectric actuator efficiency. The genetic algorithm is used for these purposes. The finite element model is a single layer triangular plate/shell element with 24 degrees of freedom for the generalized displacements, and one electrical potential degree of freedom for each piezoelectric element layer, which can be surface bonded or embedded on the laminate. To achieve a mechanism of active control of the structure dynamic response, a feedback control algorithm is used, coupling the sensor and active piezoelectric layers. To calculate the dynamic response of the laminated structures the Newmark method is considered. The model is applied in the solution of an illustrative case and the results are presented and discussed

High-Cycle Fatigue Behaviour of Polyetheretherketone (PEEK) Produced by Additive Manufacturing

Publisher Copyright: © 2023 by the authors.Polyetheretherketone (PEEK) is the leading high-performance thermoplastic biomaterial that can be processed through material extrusion (ME) additive manufacturing (AM), also known as three-dimensional (3D) printing, for patient-specific load-bearing implant manufacture. Considering the importance of cyclic loading for load-bearing implant design, this work addresses the high-cycle fatigue behaviour of 3D-printed PEEK. In this work, printed PEEK specimens are cyclically loaded under stress-controlled tension–tension using different stress levels between 75% and 95% of printed PEEK’s tensile strength. The experimental results are used to document 3D-printed PEEK’s fatigue behaviour using Basquin’s power law, which was compared with previous fatigue research on bulk PEEK and other 3D-printing materials. As a pioneering study on its fatigue behaviour, the results from this work show that 3D-printed PEEK exhibits an above-average fatigue strength of 65 MPa, corresponding to about 75% of its tensile strength. Fracture surface analysis suggests that a transition can occur from ductile to brittle fracture with maximum stresses between 85% and 95% of the tensile strength. Evidence of crack propagation features on fracture surfaces under scanning electron microscope (SEM) observation suggests crack initiation in void defects created by printing deposition that propagates longitudinally through line bonding interfaces along layers. Considering this, 3D-printed PEEK’s fatigue behaviour can be strongly related to printing conditions. Further research on the fatigue behaviour of 3D-printed PEEK is necessary to support its use in load-bearing implant applications.publishersversionpublishe

Improvement of tensile and flexural properties of 3D printed PEEK through the increase of interfacial adhesion

The authors acknowledge Fundação para a Ciência e a Tecnologia (FCT, I.P.) for its financial support through the PhD scholarship UI/BD/151082/2021 and through UNIDEMI, project UIDB/00667/2020. The authors would also like to thank João O. Cardoso for the support provided with the DSC analysis equipment.Polyetheretherketone (PEEK) is the leading high-performance biocompatible thermoplastic for the replacement of metals in orthopaedic applications. PEEK processing using material extrusion (ME) Additive Manufacturing (AM) techniques such as Fused Filament Fabrication (FFF) highlight its potential for the manufacture of patient-specific load-bearing implantable medical devices. As a high temperature semi-crystalline polymer, the mechanical properties of PEEK 3D printed samples are significantly influenced by printing parameters, particularly the crystallinity and interfacial adhesion of 3D printed parts. Given these challenges, the printing parameters of nozzle temperature, zone heater temperature, layer height and extruder multiplier were selected and studied for their effects in the interfacial adhesion and thus consequent mechanical performance of PEEK 3D prints. Design of Experiment (DoE) studies were conducted where the Taguchi and ANOVA analysis were used to determine the optimal parameter combinations and respective contributions. Additionally, different infill configurations were used with the optimal parameters to lower the samples' void volume and increase interface bonding. Reductions of up to 65 % in void volume were obtained with an interlayer translation of the infill lines and the tested configurations yielded improvements in both the tensile and flexural properties of 3D printed PEEK. Furthermore, high-temperature annealing treatments produced further increases in the strength, stiffness and crystallinity of PEEK samples. With this, significant improvements in both the void volume and the tensile and flexural properties of PEEK prints were achieved in support of the use of 3D printed PEEK in the manufacture of custom-made and high performance implantable medical devices.publishersversionpublishe

Insights into the accessory genome of two pseudomonas aeruginosa clinical isolates using comparative genomics

Recently, we have set a collaboration with Hospital de Braga, located in the North of Portugal, that handles over 600 P. aeruginosa isolates per year, aiming to rouse a holistic research approach to provide relevant information and tools to the clinicians to circumvent the multi-resistance phenomena in P. aeruginosa. Since then, we have set procedures aiming a systematic phenotypic characterization of the clinical isolates and developed strategies for the identification of pathogenicity islands and SNPs among the clinical isolates via comparative genomics. In this context, we have determined the full genome sequence of two clinical isolates using the high-throughput system Illumina Genome Analyzer IIx. These two clinical isolates, named 138244 and 152504, are representatives of allelic sequence types ST175 (widely disseminated and associated with multidrug-resistance) and ST560 (rare allele), respectively. Importantly, under standardized experimental procedures, isolate 138244 did not produce pigments and evidenced an antibiotic pan-resistant phenotype whereas 152504 produced a high amount of pyocyanin pigment and was susceptible to all antibiotics tested. A comparative genomic analysis using the genome sequences of both isolates and of all P. aeruginosa strains deposited in Genbank so far, allowed the identification of the accessory genome content of both isolates. Apparently, isolate 152504 harbors in its genome 254 unique genes, often clustered together in the same locus. Based on the genome annotation information, the pool of unique genes mainly encode several virulence factors, chemical stress resistance systems as well as 183 hypothetical proteins, 45 of which predicted members of the secretome of P. aeruginosa 152504. The accessory genome of 138244 mainly includes genes associated with mobile elements (phages, transposases, integrons) and genes encoding for 160 hypothetical proteins. Currently, research approaches are focused on the functional elucidation of sets of genes encoding hypothetical proteins of both isolates and in the description and characterization of their secretomes.Fundação para a Ciência e a Tecnologia (FCT

Comparing the effects of glazing and chitosan-based coating applied on frozen salmon on its organoleptic and physicochemical characteristics over six-months storage

The perishable nature of fish, with an increase in fish consumption in recent years, led to the improvement of fish preservation techniques. Chitosan coatings adds to the traditional water glazing. The effect of a chitosan solution of 1.5% on the sensory properties of Atlantic salmon (Salmo salar) was studied over six months of storage. The sensory properties of the salmon were assessed through the use of a texturometer and a trained panel of judges. Microbiological parameters were studied in the form of Total Volatile Base Nitrogen (TVB-N) and Total Viable Count (TVC) tests. Microbiological analysis showed that chitosan had an anti-microbiological effect on the salmon samples, reducing the number of microorganisms present, while TVB-N values were maitained stable during experiment. Textural Profile Analysis (TPA) was performed and the results showed no significant differences between different coatings regarding texture. Sensory analysis by a trained panel showed that chitosan was a better choice in frozen samples, while in thawed and cooked samples no significant differences existed between chitosan-coated and glazed samples. Flavor diffusion from the chitosan coating was assessed, and analysis of the results showed no correlation between coating type and sample flavor, indicating that no flavor diffusion had occurred.The contribution of VANIBRU, Lda. regarding the PhD scholarship of Nuno Soares and the use of industrial facilities are gratefully acknowledged

Comparative genomics of two pseudomonas aeruginosa clinical isolates to elucidate the composition of their mobilomes

Recently, we have set a collaboration with Hospital de Braga, located in the North of Portugal, that handles over 600 P. aeruginosa isolates per year, aiming to rouse a holistic research approach to provide relevant information and tools to the clinicians to circumvent the multi-resistance phenomena in P. aeruginosa. Since then, we have set procedures aiming a systematic phenotypic characterization of the clinical isolates and developed strategies for the identification of pathogenicity islands and SNPs among the clinical isolates via comparative genomics. In this context, we have determined the full genome sequence of two clinical isolates using the high-throughput system Illumina Genome Analyzer IIx. These two clinical isolates, named 138244 and 152504, are representatives of allelic sequence types ST175 (widely disseminated and associated with multidrug-resistance) and ST560 (rare allele), respectively. Importantly, under standardized experimental procedures, isolate 138244 did not produce pigments and evidenced an antibiotic pan-resistant phenotype whereas 152504 produced a high amount of pyocyanin pigment and was susceptible to all antibiotics tested. A comparative genomic analysis using the genome sequences of both isolates and of all P. aeruginosa strains deposited in Genbank so far, allowed the identification of the accessory genome content of both isolates. Apparently, isolate 152504 harbors in its genome 243 unique genes, often clustered together in the same locus. Based on the genome annotation information, the pool of unique genes mainly encode several virulence factors, chemical stress resistance systems as well as 106 hypothetical proteins, some of which predicted members of the secretome of P. aeruginosa 152504. The accessory genome of 138244 mainly includes genes associated with mobile elements (phages, transposases, integrons) and genes encoding for 190 hypothetical proteins. Currently, research approaches are focused on the functional elucidation of sets of genes encoding hypothetical proteins of both isolates and in the description and characterization of their secretomes.Fundação para a Ciência e a Tecnologia (FCT

Coffee Diterpene Derivatives as Anti-angiogenesis Agent

Among the several compounds present in coffee, the coffee-specific diterpenes have been identified as important chemoprotective agents which possess anti-carcinogenic properties.info:eu-repo/semantics/publishedVersio