On C0 and C1 continuity of envelopes of rotational solids and its application to 5-axis CNC machining

We study the smoothness of envelopes generated by motions of rotational rigid bodies in the context of 5-axis Computer Numerically Controlled (CNC) machining. A moving cutting tool, conceptualized as a rotational solid, forms a surface, called envelope, that delimits a part of 3D space where the tool engages the material block. The smoothness of the resulting envelope depends both on the smoothness of the motion and smoothness of the tool. While the motions of the tool are typically required to be at least C2, the tools are frequently only C0 continuous, which results in discontinuous envelopes. In this work, we classify a family of instantaneous motions that, in spite of only C0 continuous shape of the tool, result in C0 continuous envelopes. We show that such motions are flexible enough to follow a free-form surface, preserving tangential contact between the tool and surface along two points, therefore having applications in shape slot milling or in a semi-finishing stage of 5-axis flank machining. We also show that C1 tools and motions still can generate smooth envelopes.Juan de la Cierva - Formation [grant number FJC2019-039804-I] Ram\ón y Cajal fellowship RYC-2017-22649

Salmonella enterica biofilm-mediated dispersal by nitric oxide donors in association with cellulose nanocrystal hydrogels

Protected by extracellular polymers, microbes within biofilms are significantly more resistant to disinfectants. Current research has been instrumental in identifying nitric oxide donors and hydrogels as potential disinfectant additives. Nitric oxide (NO) donors are considered a very promising molecule as biofilm dispersal agents and hydrogels have recently attracted a lot of interest due to their biocompatible properties and ability to form stable thin films. When the NO donor MAHMA NONOate was dissolved in phosphate saline buffer, it was able to reduce the biomass of well-established biofilms up to 15% for at least 24 h of contact time. Encapsulation of MAHMA NONOate and molsidomine within a hydrogel composed of cellulose nanocrystals (CNC) has shown a synergistic effect in dispersing well-established biofilms: after 2 h of exposure, moderate but significant dispersion was measured. After 6 h of exposure, the number of cells transitioning from the biofilm to the planktonic state was up to 0.6 log higher when compared with non-treated biofilms. To further explore the transport processes of NO donors within hydrogels, we measured the nitric oxide flux from gels, at 25°C for a composite of 0.1 µM MAHMA NONOate–CNC. Nitric oxide diffuses up to 500 µm from the hydrogel surface, with flux decreasing according to Fick’s law. 60% of NO was released from the hydrogel composite during the first 23 min. These data suggest that the combined treatments with nitric oxide donor and hydrogels may allow for new sustainable cleaning strategies

Functional, immunological and three-dimensional analysis of chemically synthesisedsporozoite peptides as components of a fully-effective antimalarial vaccine

Our ongoing search for a fully-effective vaccine against the Plasmodium falciparum parasite (causing the most lethal form ofhuman malaria) has been focused on identifying and characterising proteins' amino acid sequences (high activity binding peptides orHABPs) involved in parasite invasion of red blood cells (RBC) by the merozoite and hepatocytes by the sporozoite. Many such merozoiteHABPs have been recognised and molecularly and structurally characterised; however, native HABPs are immunologically silentsince they do not induce any immune response or protection against P. falciparum malaria infection and they have to be structurallymodified to allow them to fit perfectly into immune system molecules.A deeply structural analysis of these conserved merozoite HABPs and their modified analogues has led to rules or principles becomingrecognised for constructing a logical and rational methodology for a minimal subunit-based, multi-epitope, multi-stage, chemicallysynthesisedvaccine. The same in-depth analysis of the most relevant sporozoite proteins involved in sporozoite cell-traversal and hepatocyteinvasion as well as the hepatic stage is shown here.Specifically modifying these HABPs has resulted in a new set of potential pre-erythrocyte targets which are able to induce high, longlastingantibody titres in Aotus monkeys, against their corresponding recombinant proteins and the complete parasite native molecules.This review shows how these rules may be applied against the first stage of parasite invasion (i.e. the sporozoite) to mount the first line ofdefence against the malarial parasite, which may indeed be the most effective one. Our results strongly support including some of thesemodified sporozoite HABPs in combination with the previously-described modified merozoite HABPs for obtaining the aforementionedfully-protective, multiepitope, multi-stage, minimal subunit-based, chemically-synthesized, antimalarial vaccine. © 2011 Bentham Science Publishers

Charge Polarization around Impurities in Strained Graphene

Introducing quasiparticle anisotropy in graphene via uniaxial strain has a profound effect on the polarization charge density induced by external impurities, both Coulomb and short-range. In particular the charge distribution induced by a Coulomb impurity exhibits a power law tail modulated by a strain-dependent admixture of angular harmonics. The appearance of distributed charge is in sharp contrast to the response in pristine/isotropic graphene, where for subcritical impurities the polarization charge is fully localized at the impurity position. It is also interesting to note that our results are obtained strictly at zero chemical potential, and the behavior is fundamentally distinct from the typical Friedel oscillations observed at finite chemical potential. For weak to moderate strain, the $d$-wave symmetry is dominant. The presence of Dirac cone tilt, relevant to some 2D materials beyond graphene, can also substantially affect the induced charge distribution. Finally we consider impurities with short range potentials, and study the effect of strain on the charge response. Our results were obtained in the continuum via perturbation theory valid for weak (subcritical) potentials, and supported by numerical lattice simulations based on density functional theory.Comment: 11 pages, 9 figure

Surgical Management of Cavernous Malformations Presenting with Drug-Resistant Epilepsy

Cerebral cavernous malformations (CMs) are dynamic lesions characterized by continuous size changes and repeated bleeding. When involving cortical tissue, CMs pose a significant risk for the development of drug-resistant epilepsy, which is thought to be result of an altered neuronal network caused by the lesion itself and its blood degradation products. Preoperative evaluation should comprise a complete seizure history, neurological examination, epilepsy-oriented MRI, EEG, video-EEG, completed with SPECT, PET, functional MRI, and/or invasive monitoring as needed. Radiosurgery shows variable rates of seizure freedom and a high incidence of complications, thus microsurgical resection remains the optimal treatment for CMs presenting with drug-resistant epilepsy. Two thirds of patients reach Engel I class at 3-year follow-up, regardless of lobar location. Those with secondarily generalized seizures, a higher seizure frequency, and generalized abnormalities on preoperative or postoperative EEG, show poorer outcomes, while factors such as gender, duration of epilepsy, lesion size, age, bleeding at the time of surgery, do not correlate consistently with seizure outcome. Electrocorticography and a meticulous removal of all cortical hemosiderin – beyond pure lesionectomy – reduce the risk of symptomatic recurrences

Spanish validation of the revised depression attitude questionnaire (R-daq)

Purpose: The aim of the study was to develop and validate a Spanish version of the Revised Depression Attitude Questionnaire (R-DAQ). Methods: The R-DAQ was used as a baseline for the study. It was translated and tested to ensure the instrument was appropriate for the target population. 537 Ecuadorian healthcare professionals completed the revised Spanish version of the R-DAQ (SR-DAQ). Statistical and exploratory factor analyses were performed to examine construct validity, internal consistency, readability and floor and ceiling effects. Results: Three factors were obtained: “Professional confidence in depression care”; “Therapeutic optimism about depression”; and “Generalist perspective about depression occurrence, recognition, and management”. The internal consistency of the SR-DAQ was determined by means of Cronbach’s α coefficient, with values ranging between 0.61–0.8. The correlations with the English version reflected adequate validity. The model explained 39% of the variance. Subsequent analysis with a sample restricted to those who had received training in depression produced a model that explained 42% of the variance. Conclusion: The SR-DAQ meets the psychometric requirements for measuring depression attitude in a Spanish-speaking population and shows adequate internal consistency and validity

Estudio comparativo de la raza nativa de cerdos (Zungo) con razas mejoradas.

PorciculturaMaestría en CienciasMaestrí